Applied Sciences

12 pages, 1415 KiB

Open AccessArticle

Identification of Traditional She Medicine Shi-Liang Tea Species and Closely Related Species Using the ITS2 Barcode

by Shuangjiao Ma¹, Qundan Lv^2,3, Hong Zhou¹, Jie Fang², Wenliang Cheng², Chengxi Jiang⁴, Kejun Cheng^2,4,* and Hui Yao^1,*

¹ Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China

² Chemical Biology Center, Lishui Institute of Agricultural Sciences, Lishui 323000, Zhejiang, China

³ Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China

⁴ School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China

Appl. Sci. 2017, 7(3), 195; https://doi.org/10.3390/app7030195 - 23 Feb 2017

Cited by 12 | Viewed by 6128

Abstract

Traditional She medicine is part of China’s cultural heritage and has become remarkably popular worldwide. The Shi-Liang tea is made from the processed leaves of Chimonanthus salicifolius S. Y. Hu and Chimonanthus zhejiangensis M. C. Liu. To ensure the safety and efficacy of [...] Read more.

Traditional She medicine is part of China’s cultural heritage and has become remarkably popular worldwide. The Shi-Liang tea is made from the processed leaves of Chimonanthus salicifolius S. Y. Hu and Chimonanthus zhejiangensis M. C. Liu. To ensure the safety and efficacy of Shi-Liang tea, we used DNA barcoding based on the internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA to distinguish the original plant sources of Shi-Liang tea from closely related species. All 71 ITS2 sequences were aligned by Clustal-W, and genetic distances were computed using MEGA 6.0 according to the Kimura 2-parameter model. The results indicated that the sequence lengths of ITS2 regions of the original plants of Shi-Liang tea and closely related species ranged from 256 bp to 260 bp. Interspecific genetic distances ranged from 0 to 0.078. The neighbor-joining (NJ) tree showed that the original plants of Shi-Liang tea species can be easily differentiated from closely related species. Distinct molecular differences were found between the secondary structures of ITS2 sequences from Shi-Liang tea and closely related species. The results in the present investigation suggested that the ITS2 could be an effective DNA marker to identify the original plants of Shi-Liang tea and their closely related species. These DNA barcodes can greatly benefit the supervision of the commercial circulation of She medicine. Full article

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11 pages, 929 KiB

Open AccessArticle

Tuning Guidelines for an Adaptive-Gain Parabolic Sliding Mode Filter

by Shanhai Jin¹

, Xiaodan Wang¹, Yonggao Jin¹ and Xiaogang Xiong^2,*

¹ School of Engineering, Yanbian University, Yanji 133002, China

² School of Mechanical Engineering and Automation, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, China

Appl. Sci. 2017, 7(3), 209; https://doi.org/10.3390/app7030209 - 23 Feb 2017

Cited by 3 | Viewed by 3936

Abstract

This paper quantitatively evaluates the performance of an adaptive-gain parabolic sliding mode filter (AG-PSMF), which is for removing noise in feedback control of mechatronic systems under different parameter values and noise intensities. The evaluation results show that, due to the nonlinearity of AG-PSMF, [...] Read more.

This paper quantitatively evaluates the performance of an adaptive-gain parabolic sliding mode filter (AG-PSMF), which is for removing noise in feedback control of mechatronic systems under different parameter values and noise intensities. The evaluation results show that, due to the nonlinearity of AG-PSMF, four performance measurements, i.e., transient time, overshoot magnitude, tracking error and computational time, vary widely under different conditions. Based on the evaluation results, the paper provides practical tuning guidelines for AG-PSMF to balance the tradeoff among the four measurements. The effectiveness of the guidelines is validated through numerical examples. Full article

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15 pages, 5047 KiB

Open AccessArticle

DeepGait: A Learning Deep Convolutional Representation for View-Invariant Gait Recognition Using Joint Bayesian

by Chao Li^1,*

, Xin Min¹, Shouqian Sun¹, Wenqian Lin¹ and Zhichuan Tang²

¹ College of Computer Science and Technology, Zhejiang University, Hangzhou 310027, China

² Industrial Design Institute, Zhejiang University of Technology, Hangzhou 310023, China

Appl. Sci. 2017, 7(3), 210; https://doi.org/10.3390/app7030210 - 23 Feb 2017

Cited by 89 | Viewed by 8447

Abstract

Human gait, as a soft biometric, helps to recognize people through their walking. To further improve the recognition performance, we propose a novel video sensor-based gait representation, DeepGait, using deep convolutional features and introduce Joint Bayesian to model view variance. DeepGait is generated [...] Read more.

Human gait, as a soft biometric, helps to recognize people through their walking. To further improve the recognition performance, we propose a novel video sensor-based gait representation, DeepGait, using deep convolutional features and introduce Joint Bayesian to model view variance. DeepGait is generated by using a pre-trained “very deep” network “D-Net” (VGG-D) without any fine-tuning. For non-view setting, DeepGait outperforms hand-crafted representations (e.g., Gait Energy Image, Frequency-Domain Feature and Gait Flow Image, etc.). Furthermore, for cross-view setting, 256-dimensional DeepGait after PCA significantly outperforms the state-of-the-art methods on the OU-ISR large population (OULP) dataset. The OULP dataset, which includes 4007 subjects, makes our result reliable in a statistically reliable way. Full article

(This article belongs to the Special Issue Human Activity Recognition)

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9 pages, 2270 KiB

Open AccessArticle

A Nondestructive Real-Time Detection Method of Total Viable Count in Pork by Hyperspectral Imaging Technique

by Xiaochun Zheng

, Yankun Peng^* and Wenxiu Wang

College of Engineering, China Agricultural University, 17 Qinghua East Road, Haidian, Beijing 100083, China

Appl. Sci. 2017, 7(3), 213; https://doi.org/10.3390/app7030213 - 23 Feb 2017

Cited by 29 | Viewed by 6112

Abstract

A nondestructive method was developed for assessing total viable count (TVC) in pork during refrigerated storage by using hyperspectral imaging technique in this study. The hyperspectral images in the visible/near-infrared (VIS/NIR) region of 400–1100 nm were acquired for fifty pork samples, and their [...] Read more.

A nondestructive method was developed for assessing total viable count (TVC) in pork during refrigerated storage by using hyperspectral imaging technique in this study. The hyperspectral images in the visible/near-infrared (VIS/NIR) region of 400–1100 nm were acquired for fifty pork samples, and their VIS/NIR diffuse reflectance spectra were extracted from the images. The reference values of TVC in pork samples were determined by classical microbiological plating method. Both partial least square regression (PLSR) model and support vector machine regression model (SVR) of TVC were built for comparative analysis to achieve better results. Different transformation methods and filtering methods were applied to improve the models. The results show that both the optimized PLSR model and SVR model can predict the TVC very well, while the SVR model based on second derivation was better, which achieved with R_P (correlation coefficient of prediction set) = 0.94 and SEP (standard error of prediction set) = 0.4570 log CFU/g in the prediction set. An image processing algorithm was then developed to transfer the prediction model to every pixel of the image of the entire sample; the visualizing map of TVC would be displayed in real-time during the detection process due to the simplicity of the model. The results demonstrated that hyperspectral imaging is a potential reliable approach for non-destructive and real-time prediction of TVC in pork. Full article

(This article belongs to the Special Issue Applications of Hyperspectral Imaging for Food and Agriculture)

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10 pages, 5706 KiB

Open AccessArticle

Dielectric and Impedance Analysis on the Electrical Response of Lead-Free Ba_1−xCa_xTi_0.9Zr_0.1O₃ Ceramics at High Temperature Range

by Armando Reyes-Montero¹, Paola Ramos-Alvarez¹

, Amador M. González²

, Rigoberto López-Juárez³ and María Elena Villafuerte-Castrejón^1,*

¹ Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior S/N, A.P. 70-360 CDMX, Mexico

² Grupo POEMMA, ETSIS Telecomunicación, Campus Sur, Universidad Politécnica de Madrid, Ctra. Valencia Km 7, 28031 Madrid, Spain

³ Unidad Morelia del Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex Hacienda de San José de la Huerta, C.P. 58190 Morelia, Mexico

Appl. Sci. 2017, 7(3), 214; https://doi.org/10.3390/app7030214 - 23 Feb 2017

Cited by 23 | Viewed by 6500

Abstract

Ba_1−xCa_xTi_0.9Zr_0.1O₃ (x = 0.10, 0.15, 0.18) solid solutions were synthesized by the conventional solid-state method. A perovskite-type structure was determined using the X-ray diffraction (XRD) technique. The addition of Ca²⁺ reduced [...] Read more.

Ba_1−xCa_xTi_0.9Zr_0.1O₃ (x = 0.10, 0.15, 0.18) solid solutions were synthesized by the conventional solid-state method. A perovskite-type structure was determined using the X-ray diffraction (XRD) technique. The addition of Ca²⁺ reduced the grain size (22.6, 17.9 and 13.3 μm, respectively) for all well-sintered ceramics (≈98%). Moreover, the stability temperature ranges for the tetragonal phase were promoted by displacing the ferroelectric-ferroelectric phase’s transition temperatures while T_C was maintained (86 °C). The electrical performance of the material improved as the stoichiometric composition was positioned near the morphotropic phase boundary (x = 0.15): ε_r ≈ 16,500 (T_C) at 1 kHz. For T > T_C, a thermally activated relaxation process occurred. In addition, the bulk and grain boundary processes were responsible for the conduction mechanisms. The composition x = 0.15 showed an activation energy of Ea = 1.49 eV with a maximum conductivity of σ_max = 2.48 × 10⁻² S·cm⁻¹ at 580 °C. Systematic studies at high temperature for dielectric properties were accomplished for analyzing electrical inhomogeneities associated with the grain, grain boundaries or surfaces, which are important for device design and a fundamental electrical characterization. Full article

(This article belongs to the Special Issue A Perspective on the Design of Lead-Free Piezoceramics)

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17 pages, 6250 KiB

Open AccessArticle

A Novel Denoising Method for an Acoustic-Based System through Empirical Mode Decomposition and an Improved Fruit Fly Optimization Algorithm

by Jing Xu¹, Zhongbin Wang^1,*, Chao Tan¹, Lei Si¹

and Xinhua Liu^1,2

¹ School of Mechatronic Engineering, China University of Mining & Technology, No. 1 Daxue Road, Xuzhou 221116, China

² Institute of Sound and Vibration Research, University of Southampton, Highfield, Southampton SO17 1BJ, UK

Appl. Sci. 2017, 7(3), 215; https://doi.org/10.3390/app7030215 - 23 Feb 2017

Cited by 25 | Viewed by 5446

Abstract

Generally, the sound signal produced by transmission unit or cutting unit contains abundant information about the working state of a machine. The acoustic-based diagnosis system presents some distinct advantages in some severe conditions particularly due to its unique non-contact measurement and unlimited use [...] Read more.

Generally, the sound signal produced by transmission unit or cutting unit contains abundant information about the working state of a machine. The acoustic-based diagnosis system presents some distinct advantages in some severe conditions particularly due to its unique non-contact measurement and unlimited use at the installation site. However, the original acoustic signal collected from manufacture process is always polluted by various background noises. In order to eliminate noise components from machinery sound effectively, an empirical mode decomposition (EMD) threshold denoising method optimized by an improved fruit fly optimization algorithm (IFOA) is launched in this paper. The acoustic signal was first decomposed by the adaptive EMD to obtain a series of intrinsic mode functions (IMFs). Then, the soft threshold function was applied to shrink the IMF coefficients. While the threshold of each IMF was determined by statistical estimation and empirical value for traditional EMD denoising, the denoising effect was often not desired and time-consuming. To solve these disadvantages, fruit fly optimization algorithm (FOA) was introduced to search global optimal threshold of each IMF. Moreover, to enhance the group diversity during production of the next generation of fruit flies and balance the local and global searching ability, a variation coefficient and a disturbance coefficient was introduced to the basic FOA. Then, a piece of simulated acoustic signal produced by the train was applied to validate the proposed EMD and IFOA threshold denoising (EMD-IFOA). The simulation results, which decreased 35.40% and 18.92% in mean squared error (MSE) and percent root mean square difference (PRD) respectively, and increased 40.36% in signal-to-noise ratio improvement (SNR_imp) compared with basic EMD denoising scheme at SNR = 5 dB, illustrated the effectiveness and superiority of the proposed approach. Finally, the proposed EMD-IFOA was conducted on an actual acoustic-based diagnosis system for cutting state recognition of the coal mining shearer to demonstrate the practical effect. Full article

(This article belongs to the Section Acoustics and Vibrations)

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11 pages, 1979 KiB

Open AccessArticle

Thermal and Fatigue Evaluation of Asphalt Mixtures Containing RAP Treated with a Bio-Agent

by Karol J. Kowalski^1,*

, Jan B. Król¹

, Wojciech Bańkowski²

, Piotr Radziszewski¹

and Michał Sarnowski¹

¹ Faculty of Civil Engineering, Warsaw University of Technology, Warsaw 00-637, Poland

² The Road and Bridge Research Institute, Warsaw 03-302, Poland

Appl. Sci. 2017, 7(3), 216; https://doi.org/10.3390/app7030216 - 23 Feb 2017

Cited by 56 | Viewed by 6828

Abstract

Environment conservation and diminishing natural resources caused an increase in popularity of the application of renewable bio-origin resources for the construction of road pavement. Currently, there are known additions of bio-origin materials for bitumen modification. Such material is also used as a flux [...] Read more.

Environment conservation and diminishing natural resources caused an increase in popularity of the application of renewable bio-origin resources for the construction of road pavement. Currently, there are known additions of bio-origin materials for bitumen modification. Such material is also used as a flux additive for bitumen or as a rejuvenator once working with reclaimed asphalt pavement (RAP). This paper presents research dealing with asphalt mixtures with RAP modified with a bio-agent of rapeseed origin. The main idea of the conducted research was to apply more RAP content directly to the batch mix plant without extra RAP heating. The RAP used in this study was milled from a base asphalt layer; the addition of RAP stiffens new asphalt mixtures. A bio-agent, due to its fluxing action, was used to support the asphalt mixing process and to decrease the over-stiffening of the mixture caused by RAP addition. This research includes bitumen and mixture tests. For the bitumen study, three different bitumens (35/50, 50/70, and 70/100) were tested in a dynamic shear rheometer (DSR) for complex modulus G* and for phase angle |δ| in the temperature range 0–100 °C. The reference mixture and mixtures with 2.5% bio-agent were tested to assess the influence of RAP and the bio-agent addition on the asphalt mixture properties. Low temperature behavior (TSRST), stiffness, and fatigue resistance (4PB) were tested. Based on the bitumen test, it was determined that even a low rate of bio-agent (2.5%) beneficially changes bitumen properties at a low temperature; moreover, polymerization processes occurring in the second stage of the process improves bitumen properties at a high operational temperature. The research with these asphalt mixtures demonstrates that the bio-origin flux acts as a rejuvenator and allows for an application of 30% cold RAP. Thermal cracking resistance of the mixture with RAP and 2.5% bio-agent improved. The bio-agent removes unfavorable stiffening of RAP and increases the fatigue resistance of the asphalt mixture. Full article

(This article belongs to the Special Issue Advanced Asphalt Materials and Paving Technologies)

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14 pages, 958 KiB

Open AccessArticle

Time Series Prediction Based on Adaptive Weight Online Sequential Extreme Learning Machine

by Junjie Lu

, Jinquan Huang^* and Feng Lu

Jiangsu Province Key Laboratory of Aerospace Power Systems, College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

Appl. Sci. 2017, 7(3), 217; https://doi.org/10.3390/app7030217 - 2 Mar 2017

Cited by 12 | Viewed by 4483

Abstract

A novel adaptive weight online sequential extreme learning machine (AWOS-ELM) is proposed for predicting time series problems based on an online sequential extreme learning machine (OS-ELM) in this paper. In real-world online applications, the sequentially coming data chunk usually possesses varying confidence coefficients, [...] Read more.

A novel adaptive weight online sequential extreme learning machine (AWOS-ELM) is proposed for predicting time series problems based on an online sequential extreme learning machine (OS-ELM) in this paper. In real-world online applications, the sequentially coming data chunk usually possesses varying confidence coefficients, and the data chunk with a low confidence coefficient tends to mislead the subsequent training process. The proposed AWOS-ELM can improve the training process by accessing the confidence coefficient adaptively and determining the training weight accordingly. Experiments on six time series prediction data sets have verified that the AWOS-ELM algorithm performs better in generalization performance, stability, and prediction ability than the OS-ELM algorithm. In addition, a real-world mechanical system identification problem is considered to test the feasibility and efficacy of the AWOS-ELM algorithm. Full article

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21 pages, 918 KiB

Open AccessArticle

Modeling and Solving the Three Seaside Operational Problems Using an Object-Oriented and Timed Predicate/Transition Net

by Hsien-Pin Hsu^1,*

, Chia-Nan Wang^2,3,*

, Chien-Chang Chou⁴, Ying Lee¹ and Yuan-Feng Wen¹

¹ Department of Supply Chain Management, National Kaohsiung Marine University, 81157 Kaohsiung, Taiwan

² Department of Industrial Engineering and Management, National Kaohsiung University of Applied Sciences, 80778 Kaohsiung, Taiwan

³ Department of Industrial Engineering and Management, Fotune Institute of Technology, 83158 Kaohsiung, Taiwan

⁴ Department of Shipping Technology, National Kaohsiung Marine University, 81157 Kaohsiung, Taiwan

Appl. Sci. 2017, 7(3), 218; https://doi.org/10.3390/app7030218 - 24 Feb 2017

Cited by 12 | Viewed by 4535

Abstract

Container terminals (CTs) play an essential role in the global transportation system. To deal with growing container shipments, a CT needs to better solve the three essential seaside operational problems; berth allocation problem (BAP), quay crane assignment problem (QCAP), and quay crane scheduling [...] Read more.

Container terminals (CTs) play an essential role in the global transportation system. To deal with growing container shipments, a CT needs to better solve the three essential seaside operational problems; berth allocation problem (BAP), quay crane assignment problem (QCAP), and quay crane scheduling problem (QCSP), which affect the performance of a CT considerably. In past studies, the three seaside operational problems have often been solved individually or partially, which is likely to result in poor overall system performance. However, solving the three seaside operational problems simultaneously is in fact a very complicated task. In this research, we dealt with the three seaside operational problems at the same time by using a novel high-level Petri net, termed an Object-Oriented and Timed Predicate/Transition Net (OOTPr/Tr net). After defining the three seaside operational problems formally, we integrated them as a three-level framework that was further transformed into an OOTPr/Tr net model. Then, using the Prolog programming language, we implemented this model as a simulation tool to find the best solution based on the various combinations of heuristic rules used. Full article

(This article belongs to the Special Issue Modeling, Simulation, Operation and Control of Discrete Event Systems)

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29 pages, 1324 KiB

Open AccessArticle

Robust Backstepping Control of Wing Rock Using Disturbance Observer

by Dawei Wu

, Mou Chen^*

, Huajun Gong and Qingxian Wu

College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

Appl. Sci. 2017, 7(3), 219; https://doi.org/10.3390/app7030219 - 24 Feb 2017

Cited by 16 | Viewed by 4415

Abstract

Wing rock is a highly nonlinear phenomenon when the aircraft suffers undesired roll-dominated oscillatory at high angle of attack (AOA). Considering the strong nonlinear and unsteady aerodynamic characteristics, an uncertain multi-input and multi-output (MIMO) nonlinear wing rock model is studied, and system uncertainties, [...] Read more.

Wing rock is a highly nonlinear phenomenon when the aircraft suffers undesired roll-dominated oscillatory at high angle of attack (AOA). Considering the strong nonlinear and unsteady aerodynamic characteristics, an uncertain multi-input and multi-output (MIMO) nonlinear wing rock model is studied, and system uncertainties, unsteady aerodynamic disturbances and externaldisturbancesareconsideredinthedesignofwingrockcontrollaw. Tohandletheproblemof multipledisturbances,arobustcontrolschemeisproposedbasedontheextendedstateobserver(ESO) and the radial basis function neural network (RBFNN) technique. Considering that the effectiveness of actuators are greatly decreased at high AOA, the input saturation problem is also handled by constructing a corresponding auxiliary system. Based on the improved ESO and the auxiliary system, a robust backstepping control law is proposed for the wing rock control. In addition, the dynamic surface control (DSC) technique is introduced to avoid the tedious computations of time derivatives for the virtual control laws in the backstepping method. The stability of the closed-loop system is guaranteed via rigorously Lyapunov analysis. Finally, simulation results are presented to illustrate the effectiveness of the ESO and the proposed wing rock control approach. Full article

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17 pages, 2416 KiB

Open AccessArticle

Extended Backstepping Sliding Controller Design for Chattering Attenuation and Its Application for Servo Motor Control

by Li-Hsin Chen and Chao-Chung Peng^*

Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan

Appl. Sci. 2017, 7(3), 220; https://doi.org/10.3390/app7030220 - 27 Feb 2017

Cited by 22 | Viewed by 5525

Abstract

This paper presents a robust backstepping design for motion control in the presence of model uncertainties and exogenous disturbances. The main difficulty in dealing with motion control is to reduce the effect of friction, which exists in the moving mechanism and induces nonlinear [...] Read more.

This paper presents a robust backstepping design for motion control in the presence of model uncertainties and exogenous disturbances. The main difficulty in dealing with motion control is to reduce the effect of friction, which exists in the moving mechanism and induces nonlinear behavior. In this study, the friction dynamic is considered as the external disturbance, and the proposed backstepping control algorithm is integrated with the sliding mode control, so that the effect of matching disturbances can be eliminated. The proposed approach guarantees the system asymptotic stability, globally, without significant chatter. Therefore, the developed algorithm can be realized for practical manufacturing motion control stages. Experiments including positioning and tracking controls are conducted to demonstrate the feasibility of the proposed method. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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16 pages, 1147 KiB

Open AccessArticle

Performance Comparison of Time-Frequency Distributions for Estimation of Instantaneous Frequency of Heart Rate Variability Signals

by Nabeel Ali Khan^1,*

, Peter Jönsson²

and Maria Sandsten³

¹ Department of Electrical Engineering, Foundation University, Islamabad 44000, Pakistan

² School of Education and Environment, Centre for Psychology, Kristianstad University, Kristianstad 291 88, Sweden

³ Mathematical Statistics, Centre for Mathematical Sciences, Lund University, Lund 221 00, Sweden

Appl. Sci. 2017, 7(3), 221; https://doi.org/10.3390/app7030221 - 27 Feb 2017

Cited by 22 | Viewed by 6888

Abstract

The instantaneous frequency (IF) of a non-stationary signal is usually estimated from a time-frequency distribution (TFD). The IF of heart rate variability (HRV) is an important parameter because the power in a frequency band around the IF can be used for the interpretation [...] Read more.

The instantaneous frequency (IF) of a non-stationary signal is usually estimated from a time-frequency distribution (TFD). The IF of heart rate variability (HRV) is an important parameter because the power in a frequency band around the IF can be used for the interpretation and analysis of the respiratory rate but also for a more accurate analysis of heart rate (HR) signals. In this study, we compare the performance of five states of the art kernel-based time-frequency distributions (TFDs) in terms of their ability to accurately estimate the IF of HR signals. The selected TFDs include three widely used fixed kernel methods: the modified B distribution, the S-method and the spectrogram; and two adaptive kernel methods: the adaptive optimal kernel TFD and the recently developed adaptive directional TFD. The IF of the respiratory signal, which is usually easier to estimate as the respiratory signal is a mono-component with small amplitude variations with time, is used as a reference to examine the accuracy of the HRV IF estimates. Experimental results indicate that the most reliable estimates are obtained using the adaptive directional TFD in comparison to other commonly used methods such as the adaptive optimal kernel TFD and the modified B distribution. Full article

(This article belongs to the Special Issue Application of Signal Processing Methods for Systematic Analysis of Physiological Health)

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14 pages, 1394 KiB

Open AccessArticle

Adsorption of Chromium (VI) on Calcium Phosphate: Mechanisms and Stability Constants of Surface Complexes

by Ahmed Elyahyaoui^1,*, Kawtar Ellouzi¹, Hamzeh Al Zabadi²

, Brahim Razzouki³, Saidati Bouhlassa¹, Khalil Azzaoui⁴

, El Miloud Mejdoubi⁴, Othman Hamed⁵, Shehdeh Jodeh^5,*

and Abdellatif Lamhamdi^4,6

¹ Laboratory of Radiochemistry, Department of Chemistry, Faculty of Sciences, Mohamed V-Agdal, B.P 1014 Rabat, Morocco

² Public Health Department, An-Najah National University, P.O. Box 7, Nablus 44830, Palestine

³ Laboratory of Spectroscopy, Molecular Modeling, Materials and Environment, Department of Chemistry, Faculty of Sciences, Mohamed V, B.P 1014 Rabat, Morocco

⁴ Laboratory LMSAC, Faculty of Sciences, Mohamed 1st University, P.O. Box 717, Oujda 60000, Morocco

⁵ Department of Chemistry, An-Najah National University, P.O. Box 7, Nablus 44830, Palestine

⁶ National School of Applied Sciences Al Hoceima, Mohamed 1st University, P.O. Box 717, Oujda 60000, Morocco

Appl. Sci. 2017, 7(3), 222; https://doi.org/10.3390/app7030222 - 28 Feb 2017

Cited by 28 | Viewed by 6640

Abstract

The adsorption of chromate on octacalcium phosphate (OCP) was investigated as a function of contact time, surface coverage, and solution pH [...] Full article

(This article belongs to the Special Issue Wastewater Treatment and Reuse Technologies)

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10 pages, 642 KiB

Open AccessArticle

Existence, Stability and Dynamics of Nonlinear Modes in a 2D PartiallyPT Symmetric Potential

by Jennie D’Ambroise^1,* and Panayotis G. Kevrekidis²

¹ Department of Mathematics, Computer & Information Science, State University of New York (SUNY) College at Old Westbury, Westbury, NY 11568, USA

² Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003, USA

Appl. Sci. 2017, 7(3), 223; https://doi.org/10.3390/app7030223 - 27 Feb 2017

Cited by 1 | Viewed by 4055

Abstract

It is known that multidimensional complex potentials obeying parity-time(PT)symmetry may possess all real spectra and continuous families of solitons. Recently, it was shown that for multi-dimensional systems, these features can persist when the parity symmetry condition is relaxed so that the potential is [...] Read more.

It is known that multidimensional complex potentials obeying parity-time(PT)symmetry may possess all real spectra and continuous families of solitons. Recently, it was shown that for multi-dimensional systems, these features can persist when the parity symmetry condition is relaxed so that the potential is invariant under reﬂection in only a single spatial direction. We examine the existence, stability and dynamical properties of localized modes within the cubic nonlinear Schrödinger equation in such a scenario of partiallyPT-symmetric potential. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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23 pages, 4748 KiB

Open AccessFeature PaperArticle

Effects of the Distance from a Diffusive Surface on the Objective and Perceptual Evaluation of the Sound Field in a Small Simulated Variable-Acoustics Hall

by Louena Shtrepi^*

, Arianna Astolfi

, Giuseppina Emma Puglisi and Marco Carlo Masoero

Energy Department, Politecnico di Torino, Corso Duca Degli Abruzzi 24, Torino 10129, Italy

Appl. Sci. 2017, 7(3), 224; https://doi.org/10.3390/app7030224 - 28 Feb 2017

Cited by 39 | Viewed by 6389

Abstract

Simulations of the acoustic effects that diffusive surfaces have on the objective acoustic parameters and on sound perception have not yet been fully understood. To this end, acoustic simulations have been performed in Odeon in the model of a variable-acoustic concert hall. This [...] Read more.

Simulations of the acoustic effects that diffusive surfaces have on the objective acoustic parameters and on sound perception have not yet been fully understood. To this end, acoustic simulations have been performed in Odeon in the model of a variable-acoustic concert hall. This paper is presented as a follow-up study to a previous paper that dealt with in-field measurements only. As in measurements, a diffusive and a reflective condition of one of the lateral walls have been considered in the room models. Two modeling alternatives of the diffusive condition, that is, (a) a flat surface with high scattering coefficient applied; and (b) a triangular relief modeled including edge diffraction, have been investigated. Objective acoustic parameters, such as early decay time (EDT), reverberation time (T₃₀), clarity (C₈₀), definition (D₅₀), and interaural cross correlation (IACC), have been compared between the two conditions. Moreover, an auditory experiment has been performed to determine the maximum distance from a diffusive surface at which the simulated acoustic scattering effects are still audible. Although the simulated objective results showed a good match with measured values, the subjective results showed that the differences between the diffuse and reflective conditions become significant when model (b) is used. Full article

(This article belongs to the Special Issue Noise and Vibration Control in the Built Environment)

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16 pages, 4981 KiB

Open AccessArticle

Enhanced Agarose and Xylan Degradation for Production of Polyhydroxyalkanoates by Co-Culture of Marine Bacterium, Saccharophagus degradans and Its Contaminant, Bacillus cereus

by Shailesh S. Sawant¹

, Bipinchandra K. Salunke¹, Larry E. Taylor² and Beom Soo Kim^1,*

¹ Department of Chemical Engineering, Chungbuk National University, Cheongju, Chungbuk 28644, Korea

² Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA

Appl. Sci. 2017, 7(3), 225; https://doi.org/10.3390/app7030225 - 28 Feb 2017

Cited by 33 | Viewed by 7872

Abstract

Over reliance on energy or petroleum products has raised concerns both in regards to the depletion of their associated natural resources as well as their increasing costs. Bioplastics derived from microbes are emerging as promising alternatives to fossil fuel derived petroleum plastics. The [...] Read more.

Over reliance on energy or petroleum products has raised concerns both in regards to the depletion of their associated natural resources as well as their increasing costs. Bioplastics derived from microbes are emerging as promising alternatives to fossil fuel derived petroleum plastics. The development of a simple and eco-friendly strategy for bioplastic production with high productivity and yield, which is produced in a cost effective manner utilising abundantly available renewable carbon sources, would have the potential to result in an inexhaustible global energy source. Here we report the biosynthesis of bioplastic polyhydroxyalkanoates (PHAs) in pure cultures of marine bacterium, Saccharophagus degradans 2-40 (Sde 2-40), its contaminant, Bacillus cereus, and a co-culture of these bacteria (Sde 2-40 and B. cereus) degrading plant and algae derived complex polysaccharides. Sde 2-40 degraded the complex polysaccharides agarose and xylan as sole carbon sources for biosynthesis of PHAs. The ability of Sde 2-40 to degrade agarose increased after co-culturing with B. cereus. The association of Sde 2-40 with B. cereus resulted in increased cell growth and higher PHA production (34.5% of dry cell weight) from xylan as a carbon source in comparison to Sde 2-40 alone (22.7% of dry cell weight). The present study offers an innovative prototype for production of PHA through consolidated bioprocessing of complex carbon sources by pure and co-culture of microorganisms. Full article

(This article belongs to the Special Issue Polyhydroxyalkanoates and Their Applications)

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14 pages, 3045 KiB

Open AccessArticle

Optical Beam Deflection Based AFM with Integrated Hardware and Software Platform for an Undergraduate Engineering Laboratory

by Siu Hong Loh^*

and Wei Jie Cheah

Department of Electronic Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, 31900 Kampar, Perak, Malaysia

Appl. Sci. 2017, 7(3), 226; https://doi.org/10.3390/app7030226 - 28 Feb 2017

Cited by 8 | Viewed by 8087

Abstract

Atomic force microscopy (AFM) has been used extensively in nanoscience research since its invention. Recently, many teaching laboratories in colleges, undergraduate institutions, and even high schools incorporate AFM as an effective teaching tool for nanoscience education. This paper presents an optical beam deflection [...] Read more.

Atomic force microscopy (AFM) has been used extensively in nanoscience research since its invention. Recently, many teaching laboratories in colleges, undergraduate institutions, and even high schools incorporate AFM as an effective teaching tool for nanoscience education. This paper presents an optical beam deflection (OBD) based atomic force microscope, designed specifically for the undergraduate engineering laboratory as a teaching instrument. An electronic module for signal conditioning was built with components that are commonly available in an undergraduate electronic laboratory. In addition to off-the-shelf mechanical parts and optics, the design of custom-built mechanical parts waskept as simple as possible. Hence, the overall cost for the setup is greatly reduced. The AFM controller was developed using National Instruments Educational Laboratory Virtual Instrumentation Suite (NI ELVIS), an integrated hardware and software platform which can be programmed in LabVIEW. A simple yet effective control algorithm for scanning and feedback control was developed. Despite the use of an educational platform and low-cost components from the undergraduate laboratory, the developed AFM is capable of performing imaging in constant-force mode with submicron resolution and at reasonable scanning speed (approximately 18 min per image). Therefore, the AFM is suitable to be used as an educational tool for nanoscience. Moreover, the construction of the system can be a valuable educational experience for electronic and mechanical engineering students. Full article

(This article belongs to the Special Issue Dimensional Micro and Nanometrology)

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11 pages, 7166 KiB

Open AccessArticle

Microstructure and Mechanical Properties of Ti-6Al-4V Fabricated by Vertical Wire Feeding with Axisymmetric Multi-Laser Source

by Jie Fu¹, Lin Gong^1,*, Yifei Zhang², Qianru Wu¹, Xuezhi Shi¹, Junchao Chang² and Jiping Lu¹

¹ School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China

² Shenyang Siasun Robot Automation Co., Ltd., Shenyang 110168, China

Appl. Sci. 2017, 7(3), 227; https://doi.org/10.3390/app7030227 - 28 Feb 2017

Cited by 30 | Viewed by 8394

Abstract

Vertical wire feeding with an axisymmetric multi-laser source (feeding the wire vertically into the molten pool) has exhibited great advantages over LAM (laser additive manufacturing) with paraxial wire feeding, which has an anisotropic forming problem in different scanning directions. This paper investigates the [...] Read more.

Vertical wire feeding with an axisymmetric multi-laser source (feeding the wire vertically into the molten pool) has exhibited great advantages over LAM (laser additive manufacturing) with paraxial wire feeding, which has an anisotropic forming problem in different scanning directions. This paper investigates the forming ability of vertical wire feeding with an axisymmetric multi-laser source, and the microstructure and mechanical properties of the fabricated components. It has been found that vertical wire feeding with an axisymmetric multi-laser source has a strong forming ability with no anisotropic forming problem when fabricating the complex parts in a three-axis machine tool. Most of the grains in the samples are equiaxed grains, and a small amount of short columnar grains exist which are parallel to each other. The microstructure of the fabricated samples exhibits a fine basket-weave structure and martensite due to the fast cooling rate which was caused by the small size of the molten pool and the additional heat dissipation from the feeding wire. The static tensile test shows that the average ultimate tensile strength is 1140 MPa in the scanning direction and 1115 MPa in the building direction, and the average elongation is about 6% in both directions. Full article

(This article belongs to the Special Issue Materials for 3D Printing)

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24 pages, 8983 KiB

Open AccessArticle

Dynamic Response of a Simplified Turbine Blade Model with Under-Platform Dry Friction Dampers Considering Normal Load Variation

by Bingbing He¹

, Huajiang Ouyang^2,3,*, Xingmin Ren¹ and Shangwen He⁴

¹ School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xi′an 710072, China

² State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116023, China

³ School of Engineering, University of Liverpool, Liverpool L69 3GH, UK

⁴ School of Mechanics & Engineering Science, Zhengzhou University, Zhengzhou 450001, China

Appl. Sci. 2017, 7(3), 228; https://doi.org/10.3390/app7030228 - 1 Mar 2017

Cited by 30 | Viewed by 7242

Abstract

Dry friction dampers are widely used to reduce vibration. The forced vibration response of a simplified turbine blade with a new kind of under-platform dry friction dampers is studied in this paper. The model consists of a clamped blade as two rigidly connected [...] Read more.

Dry friction dampers are widely used to reduce vibration. The forced vibration response of a simplified turbine blade with a new kind of under-platform dry friction dampers is studied in this paper. The model consists of a clamped blade as two rigidly connected beams and two dampers in the form of masses which are allowed to slide along the blade platform in the horizontal direction and vibrate with the blade platform in the vertical direction. The horizontal and vertical vibrations of the two dampers, and the horizontal and transverse platform vibrations are coupled by friction at the contact interfaces which is assumed to follow the classical discontinuous Coulomb’s law of friction. The vertical motion of the dampers leads to time-varying contact forces and can cause horizontal stick-slip motion between the contact surfaces. Due to the relative horizontal motion between the dampers and the blade platform, the vertical contact forces and the resultant friction forces act as moving loads. The Finite Element (FE) method and Modal Superposition (MS) method are applied to solve the dynamic response, together with an algorithm that can capture nonsmooth transitions from stick to slip and slip to stick. Quasi-periodic vibration is found even under harmonic excitation. Full article

(This article belongs to the Special Issue Energy Dissipation and Vibration Control: Modeling, Algorithm and Devices)

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11 pages, 3041 KiB

Open AccessArticle

Influence of the Water-Cooled Heat Exchanger on the Performance of a Pulse Tube Refrigerator

by Wei Wang^1,2, Jianying Hu^1,*, Jingyuan Xu^1,2, Limin Zhang¹ and Ercang Luo¹

¹ TKey Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China

² The College of Materials Science and Opto-electronic Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

Appl. Sci. 2017, 7(3), 229; https://doi.org/10.3390/app7030229 - 28 Feb 2017

Cited by 6 | Viewed by 6351

Abstract

The water-cooled heat exchanger is one of the key components in a pulse tube refrigerator. Its heat exchange effectiveness directly influences the cooling performance of the refrigerator. However, effective heat exchange does not always result in a good performance, because excessively reinforced heat [...] Read more.

The water-cooled heat exchanger is one of the key components in a pulse tube refrigerator. Its heat exchange effectiveness directly influences the cooling performance of the refrigerator. However, effective heat exchange does not always result in a good performance, because excessively reinforced heat exchange can lead to additional flow loss. In this paper, seven different water-cooled heat exchangers were designed to explore the best configuration for a large-capacity pulse tube refrigerator. Results indicated that the heat exchanger invented by Hu always offered a better performance than that of finned and traditional shell-tube types. For a refrigerator with a working frequency of 50 Hz, the best hydraulic diameter is less than 1 mm. Full article

(This article belongs to the Special Issue Heat Transfer Processes in Oscillatory Flow Conditions)

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19 pages, 1216 KiB

Open AccessArticle

The Application of Homogenate and Filtrate from Baltic Seaweeds in Seedling Growth Tests

by Izabela Michalak^1,*

, Agnieszka Dmytryk¹, Grzegorz Schroeder² and Katarzyna Chojnacka¹

¹ Department of Advanced Material Technologies, Faculty of Chemistry, Wrocław University of Science and Technology, Smoluchowskiego 25, 50-372 Wrocław, Poland

² Faculty of Chemistry, Adam Mickiewicz University in Poznań, Umultowska 89b, 61-614 Poznań, Poland

Appl. Sci. 2017, 7(3), 230; https://doi.org/10.3390/app7030230 - 28 Feb 2017

Cited by 23 | Viewed by 4821

Abstract

Algal filtrate and homogenate, obtained from Baltic seaweeds, were applied in seedling growth tests. Radish seeds were used in order to assess algal products phytotoxicity and their biostimulant effect on growth and nutrient uptake. Algal filtrate, at concentrations ranging from 5.0% to 100% [...] Read more.

Algal filtrate and homogenate, obtained from Baltic seaweeds, were applied in seedling growth tests. Radish seeds were used in order to assess algal products phytotoxicity and their biostimulant effect on growth and nutrient uptake. Algal filtrate, at concentrations ranging from 5.0% to 100% was used for seed soaking and as a liquid biostimulant (soil and foliar application). Algal homogenate was developed for seed coating. Algal filtrate and homogenate were also enriched with Zn(II) ions in order to examine the influence on metal ion complexation. The optimal doses of algal filtrate and homogenate, as well as soaking time were established. Multi-elemental analyses of the raw biomass, filtrate, homogenate, and radish were also performed using ICP-OES (Inductively Coupled Plasma—Optical Emission Spectrometry). The best results in terms of seedlings’ length and weight were obtained using clear filtrate at a concentration of 50% applied to the soil and for homogenate applied at a dose of 50 mg/g of seeds. Clear filtrate at a concentration of 50% used for seed soaking for one hour showed the best results. The applied algal products increased the content of elements in seedlings. Among the tested products, a concentration of 50% algal filtrate is recommended for future pot and field experiments. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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13 pages, 7727 KiB

Open AccessArticle

Heat Flow Characteristics of a Newly-Designed Cooling System with Multi-Fans and Thermal Baffle in the Wheel Loader

by Yidai Liao¹, Jiwen Zhuo², Yinliang Zhang¹, Honger Guan², Heting Huang² and Huikun Cai^1,*

¹ Department of Mechanical and Electrical Engineering of Xiamen University, No. 422 Siming South Road, Xiamen 361005, Fujian, China

² Xiamen XGMA Machinery Co. Ltd., No. 668 Xiagong Machinery Industrial Park, Guankou Town, Xiamen 361023, Fujian, China

Appl. Sci. 2017, 7(3), 231; https://doi.org/10.3390/app7030231 - 1 Mar 2017

Cited by 7 | Viewed by 5880

Abstract

In the traditional cooling case, there is usually one fan in charge of heat transfer and airflow for all radiators. However, this seems to be inappropriate, or even insufficient, for modern construction machinery, as its overall heat flow density is increasing but thermal [...] Read more.

In the traditional cooling case, there is usually one fan in charge of heat transfer and airflow for all radiators. However, this seems to be inappropriate, or even insufficient, for modern construction machinery, as its overall heat flow density is increasing but thermal distribution is becoming uneven. In order to ensure that the machine works in a better condition, this paper employs a new cooling system with multiple fans and an independent cooling region. Based on the thermal flow and performance requirements, seven fans are divided into three groups. The independent cooling region is segregated from the engine region by a thermal baffle to avoid heat flowing into the engine region and inducing an overheat phenomenon. The experiment validates the efficiency of the new cooling system and accuracy of simulation. After validation, the simulation then analyzes heat transfer and flow characteristics of the cooling system, changing with different cross-sections in different axis directions, as well as different distances of the fan central axes. Finally, thermal baffles are set among the fan groups and provided a better cooling effect. The research realizes a multi-fan scheme with an independent cooling region in a wheel loader, which is a new, but high-efficiency, cooling system and will lead to a new change of various configurations and project designs in future construction machinery. Full article

(This article belongs to the Special Issue Advances in Thermal System Analysis and Optimization)

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12 pages, 2246 KiB

Open AccessArticle

Enhanced Radiation Therapy of Gold Nanoparticles in Liver Cancer

by Meili Guo¹, Yuanming Sun^2,* and Xiao-Dong Zhang^2,3,*

¹ Department of Physics, School of Science, Tianjin Chengjian University, Tianjin 300384, China

² Tianjin Key Laboratory of Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, China

³ Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, School of Science, Tianjin University, Tianjin 300350, China

Appl. Sci. 2017, 7(3), 232; https://doi.org/10.3390/app7030232 - 1 Mar 2017

Cited by 27 | Viewed by 8076

Abstract

Gold nanoparticles (GNPs) were widely used in X-ray imaging and radiation therapy due to strong photoelectric effects and secondary electrons under high energy irradiation. As liver cancer is one of the most common forms of cancer, the use of GNPs could enhance liver [...] Read more.

Gold nanoparticles (GNPs) were widely used in X-ray imaging and radiation therapy due to strong photoelectric effects and secondary electrons under high energy irradiation. As liver cancer is one of the most common forms of cancer, the use of GNPs could enhance liver cancer radiotherapy. We synthesized polyethylene glycol (PEG)-coated GNPs of two different sizes by chemical reduction reaction. Blood stability, cellular uptake, cytotoxicity and radiation therapy were investigated. A 3–5 nm red shift of SPR caused by interactions between PEG-coated GNPs and plasma indicated their good stability. Cellular uptake assay showed that PEG-coated GNPs would enhance an appreciable uptake. GNPs preferred to combine with blood proteins, and thus induced the formation of 30–50 nm Au-protein corona. GNPs were endocytosed by cytoplasmic vesicles, localized in intracellular region, and presented concentration dependent cell viability. Clonogenic assay illustrated that the PEG-coated GNPs could sensitize two liver cancer cell lines to irradiation. Full article

(This article belongs to the Special Issue Biomaterials and Scaffolds in Tissue Engineering Applications and Cancer Therapies)

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11 pages, 2644 KiB

Open AccessArticle

Numerical Analysis and Optimization on Piezoelectric Properties of 0–3 Type Piezoelectric Cement-Based Materials with Interdigitated Electrodes

by Jianlin Luo^1,2, Chenglin You¹, Shuai Zhang³, Kwok L. Chung^1,2

, Qiuyi Li^1,4, Dongshuai Hou^1,2 and Chunwei Zhang^1,2,*

¹ School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, China

² Collaborative Innovation Center of Engineering Construction and Safety, Shandong Blue Economic Zone, Qingdao 266033, China

³ Dongying Zhu Cheng Architectural Design Co. Ltd., Dongying257091, China

⁴ Shandong Engineering Research Center for Concrete Structure Durability, Qingdao University of Technology, Qingdao 266033, China

Appl. Sci. 2017, 7(3), 233; https://doi.org/10.3390/app7030233 - 1 Mar 2017

Cited by 4 | Viewed by 4804

Abstract

The health conditions of complicated concrete structures require intrinsic cement-based sensors with a fast sensing response and high accuracy. In this paper, static, modal, harmonic, and transient dynamic analyses for the 0–3 type piezoelectric cement-based material with interdigitated electrodes (IEPCM) wafer were investigated [...] Read more.

The health conditions of complicated concrete structures require intrinsic cement-based sensors with a fast sensing response and high accuracy. In this paper, static, modal, harmonic, and transient dynamic analyses for the 0–3 type piezoelectric cement-based material with interdigitated electrodes (IEPCM) wafer were investigated using the ANSYS finite element numerical approach. Optimal design of the IEPCM was further implemented with electrode distance (P), electrode width (W), and wafer density (H) as the main parameters. Analysis results show that the maximum stress and strain in the x-polarization direction of the IEPCM are 2.6 and 3.19 times higher than that in the y-direction, respectively; there exists no repetition frequency phenomenon for the IEPCM. These indicate 0–3 type IEPCM possesses good orthotropic features, and lateral driving capacity notwithstanding, a hysteresis effect exists. Allowing for the wafer width (W_p) of 1 mm, the optimal design of the IEPCM wafer arrives at the best physical values of H, W and P are 6.2, 0.73 and 1.02 mm respectively, whereas the corresponding optimal volume is 10.9 mm³. Full article

(This article belongs to the Special Issue Structural Health Monitoring (SHM) of Civil Structures)

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21 pages, 7010 KiB

Open AccessArticle

On the Impact of Particulate Matter Distribution on Pressure Drop of Wall-Flow Particulate Filters

by Vicente Bermúdez, José Ramón Serrano

, Pedro Piqueras^* and Enrique José Sanchis

CMT-Motores Térmicos, Universitat Politècnica de València, Camino de Vera s/n, Valencia 46022, Spain

Appl. Sci. 2017, 7(3), 234; https://doi.org/10.3390/app7030234 - 2 Mar 2017

Cited by 17 | Viewed by 6911

Abstract

Wall-flow particulate filters are a required exhaust aftertreatment system to abate particulate matter emissions and meet current and incoming regulations applying worldwide to new generations of diesel and gasoline internal combustion engines. Despite the high filtration efficiency covering the whole range of emitted [...] Read more.

Wall-flow particulate filters are a required exhaust aftertreatment system to abate particulate matter emissions and meet current and incoming regulations applying worldwide to new generations of diesel and gasoline internal combustion engines. Despite the high filtration efficiency covering the whole range of emitted particle sizes, the porous substrate constitutes a flow restriction especially relevant as particulate matter, both soot and ash, is collected. The dependence of the resulting pressure drop, and hence the fuel consumption penalty, on the particulate matter distribution along the inlet channels is discussed in this paper taking as reference experimental data obtained in water injection tests before the particulate filter. This technique is demonstrated to reduce the particulate filter pressure drop without negative effects on filtration performance. In order to justify these experimental data, the characteristics of the particulate layer are diagnosed applying modeling techniques. Different soot mass distributions along the inlet channels are analyzed combined with porosity change to assess the new properties after water injection. Their influence on the subsequent soot loading process and regeneration is assessed. The results evidence the main mechanisms of the water injection at the filter inlet to reduce pressure drop and boost the interest for control strategies able to force the re-entrainment of most of the particulate matter towards the inlet channels’ end. Full article

(This article belongs to the Special Issue Internal Combustion Engines (ICE) for Ground Transport)

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15 pages, 2283 KiB

Open AccessArticle

A Timed Colored Petri Net Simulation-Based Self-Adaptive Collaboration Method for Production-Logistics Systems

by Zhengang Guo¹

, Yingfeng Zhang^1,2,*, Xibin Zhao³ and Xiaoyu Song⁴

¹ Department of Industrial Engineering, Northwestern Polytechnical University, Xi’an 710072, China

² Research & Development Institute in Shenzhen, Northwestern Polytechnical University, Shenzhen 518057, China

³ School of Software, Tsinghua University, Beijing 100084, China

⁴ Department of Electrical and Computer Engineering, Portland State University, Portland, OR 97207, USA

Appl. Sci. 2017, 7(3), 235; https://doi.org/10.3390/app7030235 - 1 Mar 2017

Cited by 47 | Viewed by 8727

Abstract

Complex and customized manufacturing requires a high level of collaboration between production and logistics in a flexible production system. With the widespread use of Internet of Things technology in manufacturing, a great amount of real-time and multi-source manufacturing data and logistics data is [...] Read more.

Complex and customized manufacturing requires a high level of collaboration between production and logistics in a flexible production system. With the widespread use of Internet of Things technology in manufacturing, a great amount of real-time and multi-source manufacturing data and logistics data is created, that can be used to perform production-logistics collaboration. To solve the aforementioned problems, this paper proposes a timed colored Petri net simulation-based self-adaptive collaboration method for Internet of Things-enabled production-logistics systems. The method combines the schedule of token sequences in the timed colored Petri net with real-time status of key production and logistics equipment. The key equipment is made ‘smart’ to actively publish or request logistics tasks. An integrated framework based on a cloud service platform is introduced to provide the basis for self-adaptive collaboration of production-logistics systems. A simulation experiment is conducted by using colored Petri nets (CPN) Tools to validate the performance and applicability of the proposed method. Computational experiments demonstrate that the proposed method outperforms the event-driven method in terms of reductions of waiting time, makespan, and electricity consumption. This proposed method is also applicable to other manufacturing systems to implement production-logistics collaboration. Full article

(This article belongs to the Special Issue Modeling, Simulation, Operation and Control of Discrete Event Systems)

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28 pages, 19601 KiB

Open AccessArticle

Full-Field Optical Coherence Tomography as a Diagnosis Tool: Recent Progress with Multimodal Imaging

by Olivier Thouvenin¹, Clement Apelian^1,2, Amir Nahas¹, Mathias Fink¹ and Claude Boccara^1,2,*

¹ Institut Langevin, ESPCI Paris, PSL Research University, 1 rue Jussieu, Paris 75005, France

² LLTech SAS, Pépinière Paris Santé Cochin 29 rue du Faubourg Saint Jacques, Paris 75014, France

Appl. Sci. 2017, 7(3), 236; https://doi.org/10.3390/app7030236 - 2 Mar 2017

Cited by 39 | Viewed by 14800

Abstract

Full-field optical coherence tomography (FF-OCT) is a variant of OCT that is able to register 2D en face views of scattering samples at a given depth. Thanks to its superior resolution, it can quickly reveal information similar to histology without the need to [...] Read more.

Full-field optical coherence tomography (FF-OCT) is a variant of OCT that is able to register 2D en face views of scattering samples at a given depth. Thanks to its superior resolution, it can quickly reveal information similar to histology without the need to physically section the sample. Sensitivity and specificity levels of diagnosis performed with FF-OCT are 80% to 95% of the equivalent histological diagnosis performances and could therefore benefit from improvement. Therefore, multimodal systems have been designed to increase the diagnostic performance of FF-OCT. In this paper, we will discuss which contrasts can be measured with such multimodal systems in the context of ex vivo biological tissue examination. We will particularly emphasize three multimodal combinations to measure the tissue mechanics, dynamics, and molecular content respectively. Full article

(This article belongs to the Special Issue Development and Application of Optical Coherence Tomography (OCT))

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13 pages, 4690 KiB

Open AccessArticle

Development of a Prolonged-Release Drug Delivery System with Magnolol Loaded in Amino-Functionalized Mesoporous Silica

by Alina Stefanache¹, Maria Ignat^2,*

, Catalina A. Peptu³, Alina Diaconu⁴, Iulian Stoleriu⁵

and Lacramioara Ochiuz^1,*

¹ Faculty of Pharmacy, Grigore. T. Popa University of Medicine and Pharmacy, Iasi 700115, Romania

² Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, Iasi 700560, Romania

³ Faculty of Chemical Engineering and Protection of the Environment, Gheorghe Asachi Technical University of Iasi, Iasi 700050, Romania

⁴ Petru Poni Institute of Macromolecular Chemistry, Iasi 700487, Romania

⁵ Faculty of Mathematics, Alexandru Ioan Cuza University of Iasi, 11 Blvd. Carol I, Iasi 700506, Romania

Appl. Sci. 2017, 7(3), 237; https://doi.org/10.3390/app7030237 - 2 Mar 2017

Cited by 16 | Viewed by 5712

Abstract

Magnolol (MG) is a small-molecule neolignan polyphenolic compound isolated from the genus Magnolia. The anti-inflammatory, anti-oxidative, anti-diabetic, anti-tumorgenic, anti-neurodegenerative, anti-depressant and anti-microbial properties of MG are well documented in recent literature. These fascinating multiple biological activities of MG encourage research about the [...] Read more.

Magnolol (MG) is a small-molecule neolignan polyphenolic compound isolated from the genus Magnolia. The anti-inflammatory, anti-oxidative, anti-diabetic, anti-tumorgenic, anti-neurodegenerative, anti-depressant and anti-microbial properties of MG are well documented in recent literature. These fascinating multiple biological activities of MG encourage research about the development of new delivery and administration approaches able to maximize its potential benefits. This study describes the amino-functionalization of the SBA-15 (Santa Barbara Amorphous) mesoporous matrix by post-synthesis grafting using APTES (3-aminopropyltriethoxysilane) and the characterization of amino-functionalized mesoporous silica SBA-15 loaded with MG in order to achieve modified drug delivery systems. The amino-functionalization of silica SBA-15 was carried out by grafting by refluxing in dry toluene. The powders obtained were characterized texturally by Brunauer-Emmett-Teller (BET) surface area analysis measurements and morphologically by scanning electron microscopy. MG loading degree in the nanoporous matrix was determined by the HPLC method at λ = 290 nm. Results showed that by grafting the amino groups in the silica SBA-15, we obtained amino-functionalized silica SBA-15 with an ordered structure, with specific surfaces and pore sizes that differ from the original matrix, which was reflected in the amount of MG immobilized and release kinetics profile. Full article

(This article belongs to the Section Nanotechnology and Applied Nanosciences)

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10 pages, 708 KiB

Open AccessArticle

Prediction of Critical Currents for a Diluted Square Lattice Using Artificial Neural Networks

by Sajjad Ali Haider, Syed Rameez Naqvi^*, Tallha Akram

and Muhammad Kamran

Department of Electrical Engineering, COMSATS Institute of Information Technology, Wah Campus, Wah Cantonment 47040, Pakistan

Appl. Sci. 2017, 7(3), 238; https://doi.org/10.3390/app7030238 - 2 Mar 2017

Cited by 11 | Viewed by 3920

Abstract

Studying critical currents, critical temperatures, and critical fields carries substantial importance in the field of superconductivity. In this work, we study critical currents in the current–voltage characteristics of a diluted-square lattice on an Nb film. Our measurements are based on a commercially available [...] Read more.

Studying critical currents, critical temperatures, and critical fields carries substantial importance in the field of superconductivity. In this work, we study critical currents in the current–voltage characteristics of a diluted-square lattice on an Nb film. Our measurements are based on a commercially available Physical Properties Measurement System, which may prove time consuming and costly for repeated measurements for a wide range of parameters. We therefore propose a technique based on artificial neural networks to facilitate extrapolation of these curves for unforeseen values of temperature and magnetic fields. We demonstrate that our proposed algorithm predicts the curves with an immaculate precision and minimal overhead, which may as well be adopted for prediction in other types of regular and diluted lattices. In addition, we present a detailed comparison between three artificial neural networks architectures with respect to their prediction efficiency, computation time, and number of iterations to converge to an optimal solution. Full article

(This article belongs to the Section Materials Science and Engineering)

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10 pages, 1697 KiB

Open AccessReview

Damage Analysis and Evaluation of Light Steel Structures Exposed to Wind Hazards

by Na Yang^1,2,* and Fan Bai^1,2

¹ School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China

² Beijing’s Key Laboratory of Structural Wind Engineering and Urban Wind Environment, Beijing 100044, China

Appl. Sci. 2017, 7(3), 239; https://doi.org/10.3390/app7030239 - 2 Mar 2017

Cited by 18 | Viewed by 8367

Abstract

Compared to hot-rolled steel structures, cold-formed steel structures are susceptible to extreme winds because of the light weight of the building and its components. Many modern cold-formed steel structures have sustained significant structural damage ranging from loss of cladding to complete collapse in [...] Read more.

Compared to hot-rolled steel structures, cold-formed steel structures are susceptible to extreme winds because of the light weight of the building and its components. Many modern cold-formed steel structures have sustained significant structural damage ranging from loss of cladding to complete collapse in recent cyclones. This article first provides some real damage cases for light steel structures induced by the high winds. After that, the paper reviews research on the damage analysis and evaluation of light steel structures caused by strong winds, which include connection failure, fatigue failure, purlin buckling, and primary frame component instability problems. Moreover, this review will mention some applications of structure damage assessment methods in this area, such as vulnerability analysis and performance-based theory, etc. Full article

(This article belongs to the Special Issue Applications of Thin-Walled Structures)

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17 pages, 3348 KiB

Open AccessArticle

Active Vibration Suppression of a Motor-Driven Piezoelectric Smart Structure Using Adaptive Fuzzy Sliding Mode Control and Repetitive Control

by Chi-Ying Lin^*

and Hong-Wu Jheng

Department of Mechanical Engineering, National Taiwan University of Science and Technology, No. 43, Keelung Rd., Sec. 4, Taipei 106, Taiwan

Appl. Sci. 2017, 7(3), 240; https://doi.org/10.3390/app7030240 - 4 Mar 2017

Cited by 24 | Viewed by 6305

Abstract

In this paper, we report on the use of piezoelectric sensors and actuators for the active suppression of vibrations associated with the motor-driven rotation of thin flexible plate held vertically. Motor-driven flexible structures are multi-input multi-output systems. The design of active vibration-suppression controllers [...] Read more.

In this paper, we report on the use of piezoelectric sensors and actuators for the active suppression of vibrations associated with the motor-driven rotation of thin flexible plate held vertically. Motor-driven flexible structures are multi-input multi-output systems. The design of active vibration-suppression controllers for these systems is far more challenging than for flexible structures with a fixed end, due to the effects of coupling and nonlinear vibration behavior generated in structures with poor damping. To simplify the design of the controller and achieve satisfactory vibration suppression, we treated the coupling of vibrations caused by the rotary motion of the thin flexible plate as external disturbances and system uncertainties. We employed an adaptive fuzzy sliding mode control algorithm in the design of a single-input–single-output controller for the suppression of vibrations using piezoelectric sensors and actuators. We also used a repetitive control system to reduce periodic vibrations associated with the repetitive motions induced by the motor. Experimental results demonstrate that the hybrid intelligent control approach proposed in this study can suppress complex vibrations caused by modal excitation, coupling effects, and periodic external disturbances. Full article

(This article belongs to the Special Issue Energy Dissipation and Vibration Control: Modeling, Algorithm and Devices)

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11 pages, 1910 KiB

Open AccessArticle

Multi-Temporal Remotely Sensed Data for Degradation Dynamics in Linxia Rangeland, Northwest China

by Xinyang Yu^1,*, Changhe Lu² and Gengxing Zhao¹

¹ College of Resources and Environment, Shandong Agricultural University, Tai’an 271018, China

² Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

Appl. Sci. 2017, 7(3), 241; https://doi.org/10.3390/app7030241 - 3 Mar 2017

Viewed by 3290

Abstract

The importance of accurately monitoring rangeland degradation dynamics over decades is increasing in Linxia rangeland, the birthplace of the Yellow River in China. Since 2000, the Chinese government has implemented the “Grain for Green” program and enforced a grazing ban in Gansu province, [...] Read more.

The importance of accurately monitoring rangeland degradation dynamics over decades is increasing in Linxia rangeland, the birthplace of the Yellow River in China. Since 2000, the Chinese government has implemented the “Grain for Green” program and enforced a grazing ban in Gansu province, one of the most degraded provinces, to mitigate the problem of rangeland degradation. The effects of these policies are controversial and have become a topic of public concern. In this study, a grading system was established for the estimation of Linxia rangeland degradation. Degrees of rangeland degradation were interpreted and the spatio-temporal dynamics of the degraded rangeland through several study periods were mapped and monitored using the Linear Spectral Mixture Analysis method on Landsat Thematic Mapper (TM)/ETM+ (Enhanced Thematic Mapper Plus) images for the years of 1996, 2001, 2006, and 2011. The results demonstrated that the time around the year 2001 appeared to be a turning point of the rangeland degradation reversion course, as the rangeland degradation reversed significantly since 2001. From 1996 to 2001, the total degraded area in Linxia rangeland increased from 2922.01 km² to 3048.48 km² (+4.33%), and decreased by 4.54% to 2909.97 km² in 2011; the non-degraded rangeland gradually increased from 602.74 km² to 710.01 km², an increase of 17.80%. Degraded rangeland vegetation was restored significantly during 2001–2011: the area of slightly degraded rangeland increased by 3.71% and 3.83% annually during 2001–2006 and 2006–2011 intervals, respectively, and the area of moderately and severely degraded rangeland decreased annually by 4.77% and 2.41% from 2001 to 2006, and 4.58% and 0.81% during 2006–2011, respectively. These results indicated that the “Grain for Green” program and grazing ban policy, together with other ecological impacting factors, helped reverse the rangeland degradation and promote the rehabilitation of rangeland vegetation. Full article

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20 pages, 2974 KiB

Open AccessArticle

Synthesis and Physical Properties of Polyhydroxyalkanoate Polymers with Different Monomer Compositions by Recombinant Pseudomonas putida LS46 Expressing a Novel PHA SYNTHASE (PhaC1₁₆) Enzyme

by Parveen K. Sharma¹, Riffat I. Munir¹, Warren Blunt¹, Chris Dartiailh¹, Juijun Cheng², Trevor C. Charles²

and David B. Levin^1,*

¹ Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada

² Department of Biology and Centre for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada

Appl. Sci. 2017, 7(3), 242; https://doi.org/10.3390/app7030242 - 3 Mar 2017

Cited by 55 | Viewed by 10222

Abstract

A recombinant of Pseudomonas putida LS461 (deletion of the phaC1phaZphaC2 genes) was constructed by introducing cosmid JC123 carrying a novel phaC1₁₆ gene from a metagenomic clone. The resulting strain, P. putida LS46123, was able to synthesize polyhydroxyalkanoate (PHA) polymers with novel monomer [...] Read more.

A recombinant of Pseudomonas putida LS461 (deletion of the phaC1phaZphaC2 genes) was constructed by introducing cosmid JC123 carrying a novel phaC1₁₆ gene from a metagenomic clone. The resulting strain, P. putida LS46123, was able to synthesize polyhydroxyalkanoate (PHA) polymers with novel monomer compositions when cultured on glucose or free fatty acids, and accumulated PHAs from 9.24% to 27.09% of cell dry weight. The PHAs synthesized by P. putida LS46123 contained up to 50 mol % short chain length subunits (3-hydroxybutyrate and 3-hydroxyvalerate), with the remaining monomers consisting of various medium chain length subunits. The PhaC1₁₆ protein expressed by P. putida LS46123 had an amino acid sequence similarity of 45% with the PhaC1 protein of the parent strain, P. putida LS46. Predicted 3D structures of the PhaC1₁₆ proteins from P. putida LS46123 and P. putida LS46 revealed several differences in the numbers and locations of protein secondary structures. The physical and thermal properties of the novel polymers synthesized by P. putida LS46123 cultured with glucose or free fatty acids differed significantly from those produced by P. putida LS46 grown on the same substrates. PHA polymers with different subunit compositions, and hence different physical and thermal properties, can be tailor-made using novel PHA synthase for specific applications. Full article

(This article belongs to the Special Issue Polyhydroxyalkanoates and Their Applications)

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12 pages, 4886 KiB

Open AccessArticle

Reconstruction to Sensor Measurements Based on a Correlation Model of Monitoring Data

by Wei Lu^1,*, Jun Teng^1,2, Chao Li¹ and Yan Cui¹

¹ Department of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, China

² College of Civil Engineering, Fujian University of Technology, Fuzhou 350118, China

Appl. Sci. 2017, 7(3), 243; https://doi.org/10.3390/app7030243 - 3 Mar 2017

Cited by 27 | Viewed by 4386

Abstract

A sensor failure will lead to sensor measurement distortion, and may reduce the reliability of the whole structure analysis. This paper studies the method of monitoring information reconstruction based on the correlation degree. For the faulty sensor, the correlation degree of the normal [...] Read more.

A sensor failure will lead to sensor measurement distortion, and may reduce the reliability of the whole structure analysis. This paper studies the method of monitoring information reconstruction based on the correlation degree. For the faulty sensor, the correlation degree of the normal response of this sensor and the measurements of the other sensors is calculated, which is also called the correlation degree of reconstructed variables and response variables. By comparing the correlation degrees, the response variables, which are needed to establish the correlation model, are determined. The correlation model between the reconstructed variables and the response variables is established by the partial least square method. The value of the correlation degrees between the reconstructed variables and the response variables, the amount of the monitoring data which is used to determine the coefficients of the correlation model, and the number of the response variables are used to discuss the influence factors of the reconstruction error. The stress measurements of structural health monitoring system of Shenzhen Bay Stadium is taken as an example, and the effectiveness of the method is verified and the practicability of the method is illustrated. Full article

(This article belongs to the Special Issue Structural Health Monitoring (SHM) of Civil Structures)

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22 pages, 7508 KiB

Open AccessArticle

Electronically Tunable Current Controlled Current Conveyor Transconductance Amplifier-Based Mixed-Mode Biquadratic Filter with Resistorless and Grounded Capacitors

by Hua-Pin Chen^1,* and Wan-Shing Yang²

¹ Department of Electronic Engineering, Ming Chi University of Technology, New Taipei 24301, Taiwan

² Department of Computer and Communication Engineering, De Lin Institute of Technology, New Taipei 23654, Taiwan

Appl. Sci. 2017, 7(3), 244; https://doi.org/10.3390/app7030244 - 4 Mar 2017

Cited by 29 | Viewed by 5893

Abstract

A new electronically tunable mixed-mode biquadratic filter with three current controlled current conveyor transconductance amplifiers (CCCCTAs) and two grounded capacitors is proposed. With current input, the filter can realise lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP) responses in current [...] Read more.

A new electronically tunable mixed-mode biquadratic filter with three current controlled current conveyor transconductance amplifiers (CCCCTAs) and two grounded capacitors is proposed. With current input, the filter can realise lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP) responses in current mode and LP, BP and HP responses in transimpedance mode. With voltage input, the filter can realise LP, BP, HP, BS and AP responses in voltage and transadmittance modes. Other attractive features of the mixed-mode biquadratic filter are (1) the use of two grounded capacitors, which is ideal for integrated circuit implementation; (2) orthogonal control of the quality factor (Q) and resonance angular frequency (ω_o) for easy electronic tenability; (3) low input impedance and high output impedance for current signals; (4) high input impedance for voltage signal; (5) avoidance of need for component-matching conditions; (6) resistorless and electronically tunable structure; (7) low active and passive sensitivities; and (8) independent control of the voltage transfer gains without affecting the parameters ω_o and Q. Full article

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15 pages, 4303 KiB

Open AccessArticle

Development of a Staggered PCD End Mill for Carbon Fiber Reinforced Plastic

by Guangjun Liu¹, Xin Qian¹, Hongyuan Chen¹, Fei Gao² and Tao Chen^2,*

¹ School of Mechanical Engineering, Tongji University, Shanghai 201804, China

² School of Mechanical and Power Engineering, Harbin University of Science and Technology, Harbin 150080, Heilongjiang, China

Appl. Sci. 2017, 7(3), 245; https://doi.org/10.3390/app7030245 - 3 Mar 2017

Cited by 5 | Viewed by 6658

Abstract

This work presents a PCD (polycrystalline diamond) end mill with a new staggered structure for the milling of CFRP (carbon fiber reinforced plastic). The magnitude and direction of cutting force is decreased and changed by side-edge re-configuration of the structure. The flute and [...] Read more.

This work presents a PCD (polycrystalline diamond) end mill with a new staggered structure for the milling of CFRP (carbon fiber reinforced plastic). The magnitude and direction of cutting force is decreased and changed by side-edge re-configuration of the structure. The flute and insert pocket of the staggered PCD end mill are designed considering the tool’s stiffness and welding process. The milling process and machining defects of the staggered PCD end mill are analyzed, and the structural parameters of the staggered PCD end mill are determined. The staggered PCD end mill is fabricated by the process of wire cutting, NC (Numerical Control) machining, high-frequency induction brazing, welding, grinding and passivation. Milling tests of multidirectional CFRP with the staggered PCD end mill is conducted on CNC (Computerized Numerical Control) milling machine. The milling force is measured by a dynamometer. A range analysis of the numerical results of milling force is conducted after milling test, and the influence of milling parameters on milling force is analyzed. A regression model of the milling force is built and verified by experiment. The effects of fiber cutting angle on milling force are obtained through milling CFRP with different fiber orientation angles. Full article

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22 pages, 5024 KiB

Open AccessReview

Metal-Insulator-Metal Single Electron Transistors with Tunnel Barriers Prepared by Atomic Layer Deposition

by Golnaz Karbasian^1,3, Michael S. McConnell^1,*, Hubert George^1,4, Louisa C. Schneider^1,5, Matthew J. Filmer¹, Alexei O. Orlov¹, Alexei N. Nazarov² and Gregory L. Snider¹

¹ Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA

² Lashkaryov Institute of Semiconductor Physics, 03028 Kyiv, Ukraine

³ Present address: Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720-1770, USA

⁴ Present address: Intel Corp, 2501 NW 229th Ave., Hillsboro, OR 97124, USA

⁵ Present address: Cypress Semiconductor Corp, 2401 East 86th St., Bloomington, MN 55425, USA

Appl. Sci. 2017, 7(3), 246; https://doi.org/10.3390/app7030246 - 3 Mar 2017

Cited by 15 | Viewed by 7281

Abstract

Single electron transistors are nanoscale electron devices that require thin, high-quality tunnel barriers to operate and have potential applications in sensing, metrology and beyond-CMOS computing schemes. Given that atomic layer deposition is used to form CMOS gate stacks with low trap densities and [...] Read more.

Single electron transistors are nanoscale electron devices that require thin, high-quality tunnel barriers to operate and have potential applications in sensing, metrology and beyond-CMOS computing schemes. Given that atomic layer deposition is used to form CMOS gate stacks with low trap densities and excellent thickness control, it is well-suited as a technique to form a variety of tunnel barriers. This work is a review of our recent research on atomic layer deposition and post-fabrication treatments to fabricate metallic single electron transistors with a variety of metals and dielectrics. Full article

(This article belongs to the Special Issue Applied Single-Electron Transistors)

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13 pages, 2105 KiB

Open AccessArticle

Natural Convection Flow of Fractional Nanofluids Over an Isothermal Vertical Plate with Thermal Radiation

by Constantin Fetecau^1,*, Dumitru Vieru² and Waqas Ali Azhar³

¹ Academy of Romanian Scientists, Bucharest 050094, Romania

² Department of Theoretical Mechanics, Technical University of Iasi, Iasi 700050, Romania

³ Abdus Salam School of Mathematical Sciences, Government College University, Lahore 54000, Pakistan

Appl. Sci. 2017, 7(3), 247; https://doi.org/10.3390/app7030247 - 3 Mar 2017

Cited by 55 | Viewed by 5948

Abstract

The studies of classical nanofluids are restricted to models described by partial differential equations of integer order, and the memory effects are ignored. Fractional nanofluids, modeled by differential equations with Caputo time derivatives, are able to describe the influence of memory on the [...] Read more.

The studies of classical nanofluids are restricted to models described by partial differential equations of integer order, and the memory effects are ignored. Fractional nanofluids, modeled by differential equations with Caputo time derivatives, are able to describe the influence of memory on the nanofluid behavior. In the present paper, heat and mass transfer characteristics of two water-based fractional nanofluids, containing nanoparticles of CuO and Ag, over an infinite vertical plate with a uniform temperature and thermal radiation, are analytically and graphically studied. Closed form solutions are determined for the dimensionless temperature and velocity fields, and the corresponding Nusselt number and skin friction coefficient. These solutions, presented in equivalent forms in terms of the Wright function or its fractional derivatives, have also been reduced to the known solutions of ordinary nanofluids. The influence of the fractional parameter on the temperature, velocity, Nusselt number, and skin friction coefficient, is graphically underlined and discussed. The enhancement of heat transfer in the natural convection flows is lower for fractional nanofluids, in comparison to ordinary nanofluids. In both cases, the fluid temperature increases for increasing values of the nanoparticle volume fraction. Full article

(This article belongs to the Special Issue Recent Developments of Nanofluids)

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15 pages, 3659 KiB

Open AccessArticle

The Effects of Wet Compression by the Electronic Expansion Valve Opening on the Performance of a Heat Pump System

by Kyoungjin Seong¹, Daehui Lee^1,2 and Jinho Lee^1,*

¹ School of Mechanical Engineering, Yonsei University, 50 Yonsei-Ro, Seodaemun-Ku, Seoul 03722, Korea

² Center of Doowon heavy industrial Co., Ltd., 51 Gwaneumdang-Gil, Juksan-Myon, Anseong-Si, Gyeonggi-Do 17520, Korea

Appl. Sci. 2017, 7(3), 248; https://doi.org/10.3390/app7030248 - 3 Mar 2017

Cited by 9 | Viewed by 6571

Abstract

In this study, by controlling the Electronic Expansion Valve opening, the influence of wet compression on a heat pump system was experimentally investigated in different heating conditions. The results demonstrate that the discharge temperature decreased and the mass flow rate increased, due to [...] Read more.

In this study, by controlling the Electronic Expansion Valve opening, the influence of wet compression on a heat pump system was experimentally investigated in different heating conditions. The results demonstrate that the discharge temperature decreased and the mass flow rate increased, due to quality of the rising liquid droplets. It was also found that the heating capacity and power input of wet compression increased more than that of dry compression, with a superheat of 10 °C. The maximum COP (Coefficient of Performance) exists at a specific quality of ca. 0.94 to 0.90, as the power input in the region of wet compression is proportionally larger than the increase in the heating capacity, according to the decreasing quality. When the Entering Water Temperature of the Outdoor Heat Exchanger was 10 °C, 5 °C, and 0 °C, the COP increased by a maximum of ca. 12.4%, 10.6%, and 10.2%, respectively, in comparison to the superheat of 10 °C. In addition, the superheat at the discharge line is proposed as a proper controlling parameter to adjust the quality at the suction line, by varying the opening of the expansion valve during wet compression. Full article

(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)

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14 pages, 2426 KiB

Open AccessArticle

A Measure Based on Beamforming Power for Evaluation of Sound Field Reproduction Performance

by Ji-Ho Chang^1,* and Cheol-Ho Jeong²

¹ Center for Fluid Flow & Acoustics, Division of Physical Metrology, Korea Research Institute of Standards and Science, Daejeon 34113, Korea

² Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark

Appl. Sci. 2017, 7(3), 249; https://doi.org/10.3390/app7030249 - 3 Mar 2017

Cited by 4 | Viewed by 4172

Abstract

This paper proposes a measure to evaluate sound field reproduction systems with an array of loudspeakers. The spatially-averaged squared error of the sound pressure between the desired and the reproduced field, namely the spatial error, has been widely used, which has considerable problems [...] Read more.

This paper proposes a measure to evaluate sound field reproduction systems with an array of loudspeakers. The spatially-averaged squared error of the sound pressure between the desired and the reproduced field, namely the spatial error, has been widely used, which has considerable problems in two conditions. First, in non-anechoic conditions, room reflections substantially deteriorate the spatial error, although these room reflections affect human localization to a lesser degree. Second, for 2.5-dimensional reproduction of spherical waves, the spatial error increases consistently due to the difference in the amplitude decay rate, whereas the degradation of human localization performance is limited. The measure proposed in this study is based on the beamforming powers of the desired and the reproduced fields. Simulation and experimental results show that the proposed measure is less sensitive to room reflections and the amplitude decay than the spatial error, which is likely to agree better with the human perception of source localization. Full article

(This article belongs to the Special Issue Spatial Audio)

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9 pages, 1356 KiB

Open AccessFeature PaperArticle

Novel Composite Powders with Uniform TiB₂ Nano-Particle Distribution for 3D Printing

by Mengxing Chen¹, Xiaopeng Li^2,*, Gang Ji³, Yi Wu¹, Zhe Chen^1,*, Wouter Baekelant⁴, Kim Vanmeensel⁵, Haowei Wang¹ and Jean-Pierre Kruth²

¹ State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China

² Department of Mechanical Engineering, University of Leuven (KU Leuven), Leuven 3001, Belgium

³ Unité Matériaux et Transformations, CNRS UMR 8207, Université Lille 1, Villeneuve d’Ascq 59655, France

⁴ Department of Chemistry, University of Leuven (KU Leuven), Leuven 3000, Belgium

⁵ Department of Materials Engineering, University of Leuven (KU Leuven), Leuven 3000, Belgium

Appl. Sci. 2017, 7(3), 250; https://doi.org/10.3390/app7030250 - 6 Mar 2017

Cited by 55 | Viewed by 9205

Abstract

It is reported that the ductility and strength of a metal matrix composite could be concurrently improved if the reinforcing particles were of the size of nanometers and distributed uniformly. In this paper, we revealed that gas atomization solidification could effectively disperse TiB [...] Read more.

It is reported that the ductility and strength of a metal matrix composite could be concurrently improved if the reinforcing particles were of the size of nanometers and distributed uniformly. In this paper, we revealed that gas atomization solidification could effectively disperse TiB₂ nanoparticles in the Al alloy matrix due to its fast cooling rate and the coherent orientation relationship between TiB₂ particles and α-Al. Besides, nano-TiB₂ led to refined equiaxed grain structures. Furthermore, the composite powders with uniformly embedded nano-TiB₂ showed improved laser absorptivity. The novel composite powders are well suited for selective laser melting. Full article

(This article belongs to the Special Issue Materials for 3D Printing)

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21 pages, 6169 KiB

Open AccessArticle

Design and Testing of a Novel Building Integrated Cross Axis Wind Turbine

by Wen Tong Chong¹

, Mohammed Gwani^1,2, Chin Joo Tan^1,*

, Wan Khairul Muzammil^1,3, Sin Chew Poh¹ and Kok Hoe Wong¹

¹ Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia

² Department of Physics, Kebbi State University of Science and Technology, Aliero, Kebbi State 1144, Nigeria

³ Faculty of Engineering, Universiti Malaysia Sabah, Jalan UMS, Sabah 88400, Malaysia

Appl. Sci. 2017, 7(3), 251; https://doi.org/10.3390/app7030251 - 8 Mar 2017

Cited by 10 | Viewed by 8768

Abstract

The prospect of harnessing wind energy in urban areas is not promising owing to low wind speeds and the turbulence caused by surrounding obstacles. However, these challenges can be overcome through an improved design of wind turbine that can operate efficiently in an [...] Read more.

The prospect of harnessing wind energy in urban areas is not promising owing to low wind speeds and the turbulence caused by surrounding obstacles. However, these challenges can be overcome through an improved design of wind turbine that can operate efficiently in an urban environment. This paper presents a novel design of a building integrated cross axis wind turbine (CAWT) that can operate under dual wind direction, i.e., horizontal wind and vertical wind from the bottom of the turbine. The CAWT consists of six horizontal blades and three vertical blades for enhancing its self-starting behavior and overall performance. The study employed a mock-up building model with gable rooftop where both of the developed CAWT and the conventional straight-bladed vertical axis wind turbine (VAWT) are mounted and tested on the rooftop. The height of the CAWT and the VAWT above the rooftop was varied from 100 to 250 mm under the same experimental conditions. The results obtained from the experimental study showed that there is significant improvement in the coefficient of power (C_p) and self-starting behavior of the building integrated CAWT compared to the straight-bladed VAWT. At 100 mm height, the C_p,max value of the CAWT increased by 266%, i.e., from 0.0345 to 0.1263, at tip speed ratio (TSR) (λ) of 1.1 and at wind speed of 4.5 m/s. Similar improvements in performance are also observed for all condition of CAWT heights above the rooftop where the CAWT outperformed the straight-bladed VAWT by 196%, 136% and 71% at TSR of 1.16, 1.08, and 1.12 for Y = 150, 200, and 250 mm, respectively. Moreover, the CAWT performs better at 10° pitch angle of the horizontal blade compared to other pitch angles. Full article

(This article belongs to the Section Energy Science and Technology)

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12 pages, 1545 KiB

Open AccessFeature PaperArticle

Synthesis of Injectable Alginate Hydrogels with Muscle-Derived Stem Cells for Potential Myocardial Infarction Repair

by Rui Fang¹

, Weiming Tian² and Xiongbiao Chen^1,3,*

¹ Division of Biomedical Engineering, University of Saskatchewan, Saskatoon S7N 5A9, Canada

² Bio-X Center, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China

³ Department of Mechanical Engineering, University of Saskatchewan, Saskatoon S7N 5A9, Canada

Appl. Sci. 2017, 7(3), 252; https://doi.org/10.3390/app7030252 - 4 Mar 2017

Cited by 17 | Viewed by 7717

Abstract

Myocardial infarction (MI), caused by the occlusion of the left ventricular coronary artery, leads to the loss of cardiomyocytes and, potentially, heart failure. Cardiomyocytes in adult mammals proliferate at an extremely low rate and thus, a major challenge in MI treatment is supplementing [...] Read more.

Myocardial infarction (MI), caused by the occlusion of the left ventricular coronary artery, leads to the loss of cardiomyocytes and, potentially, heart failure. Cardiomyocytes in adult mammals proliferate at an extremely low rate and thus, a major challenge in MI treatment is supplementing exogenous cells and keeping them viable in MI areas. To address this challenge, injecting hydrogels encapsulating cells into MI areas, to compensate for the loss of cardiomyocytes, shows promise. This study synthesized two types of alginate hydrogels, based on self-crosslinking (SCL) and calcium ion crosslinking (Ca²⁺) in varying formulations. The hydrogels encapsulated living muscle-derived stem cells (MDSCs) and their performance was evaluated in terms of optimizing cell viability during the injection process, as well as the live/dead rate after long-term cultivation. The morphology of the hydrogel-encapsulated cells was characterized by scanning electronic microscopy (SEM) and live/dead cells were examined using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide staining) assay. The mechanical properties of the hydrogels were also determined via a rheometer, to identify their influence on cell viability during the injection process and with respect to long-term cultivation. The SCL hydrogel with a 0.8% alginate and 20% gelatin formulation resulted in the highest cell viability during the injection process, and the Ca²⁺ hydrogel composed of 1.1% alginate and 20% gelatin maintained the highest cell survival rate after two months in culture. Full article

(This article belongs to the Special Issue Biomaterials and Scaffolds in Tissue Engineering Applications and Cancer Therapies)

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19 pages, 3119 KiB

Open AccessArticle

Friction Factor Correlation for Regenerator Working in a Travelling-Wave Thermoacoustic System

by Fatimah A. Z. Mohd Saat¹ and Artur J. Jaworski^2,*

¹ Centre for Advanced Research on Energy, Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia

² Faculty of Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK

Appl. Sci. 2017, 7(3), 253; https://doi.org/10.3390/app7030253 - 5 Mar 2017

Cited by 12 | Viewed by 6744

Abstract

Regenerator is a porous solid structure which is important in the travelling-wave thermoacoustic system. It provides the necessary contact surface and thermal capacity for the working gas to undergo a thermodynamic cycle under acoustic oscillatory flow conditions. However, it also creates a pressure [...] Read more.

Regenerator is a porous solid structure which is important in the travelling-wave thermoacoustic system. It provides the necessary contact surface and thermal capacity for the working gas to undergo a thermodynamic cycle under acoustic oscillatory flow conditions. However, it also creates a pressure drop that could degrade the overall system performance. Ideally, in a travelling-wave system, the phase angle between oscillating pressure and velocity in the regenerator should be zero, or as close to zero as possible. In this study, the hydrodynamic condition of a regenerator has been investigated both experimentally (in a purpose-built rig providing a travelling-wave phasing) and numerically. A two-dimensional ANSYS FLUENT CFD model, capturing the important features of the experimental conditions, has been developed. The findings suggest that a steady-state correlation, commonly used in designing thermoacoustic systems, is applicable provided that the travelling-wave phase angle is maintained. However, for coarse mesh regenerators, the results show interesting “phase shifting” phenomena, which may limit the correlation validity. Current experimental and CFD studies are important for predicting the viscous losses in future models of thermoacoustic systems. Full article

(This article belongs to the Special Issue Heat Transfer Processes in Oscillatory Flow Conditions)

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13 pages, 2588 KiB

Open AccessArticle

A Visual Analytics Approach for Detecting and Understanding Anomalous Resident Behaviors in Smart Healthcare

by Zhifang Liao¹, Lingyuan Kong¹, Xiao Wang², Ying Zhao^3,*, Fangfang Zhou³, Zhining Liao⁴ and Xiaoping Fan^3,5,*

¹ School of Software Engineering, Central South University, Changsha 410075, China

² Data Center Consolidation (Beijing), Industrial and Commercial Bank of China, Beijing 100000, China

³ School of Information Science and Engineering, Central South University, Changsha 410075, China

⁴ Division of Health & Social Care Research, Faculty of Life Sciences &Medicine, King’s College London, London WC2R 2LS, UK

⁵ Information Management Department, Hunan University of Finance and Economics, Changsha 410083, China

Appl. Sci. 2017, 7(3), 254; https://doi.org/10.3390/app7030254 - 7 Mar 2017

Cited by 22 | Viewed by 5883

Abstract

With the development of science and technology, it is possible to analyze residents’ daily behaviors for the purpose of smart healthcare in the smart home environment. Many researchers have begun to detect residents’ anomalous behaviors and assess their physical condition, but these approaches [...] Read more.

With the development of science and technology, it is possible to analyze residents’ daily behaviors for the purpose of smart healthcare in the smart home environment. Many researchers have begun to detect residents’ anomalous behaviors and assess their physical condition, but these approaches used by the researchers are often caught in plight caused by a lack of ground truth, one-sided analysis of behavior, and difficulty of understanding behaviors. In this paper, we put forward a smart home visual analysis system (SHVis) to help analysts detect and comprehend unusual behaviors of residents, and predict the health information intelligently. Firstly, the system classifies daily activities recorded by sensor devices in smart home environment into different categories, and discovers unusual behavior patterns of residents living in this environment by using various characteristics extracted from those activities and appropriate unsupervised anomaly detection algorithm. Secondly, on the basis of figuring out the residents’ anomaly degree of every date, we explore the daily behavior patterns and details with the help of several visualization views, and compare and analyze residents’ activities of various dates to find the reasons why residents act unusually. In the case study of this paper, we analyze residents’ behaviors that happened over two months and find unusual indoor behaviors and give health advice to the residents. Full article

(This article belongs to the Special Issue Smart Healthcare)

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27 pages, 4351 KiB

Open AccessArticle

Performance of a Supercritical CO₂ Bottoming Cycle for Aero Applications

by Florian Jacob^1,*, Andrew Martin Rolt¹, Joshua Marius Sebastiampillai¹, Vishal Sethi¹, Mathieu Belmonte¹ and Pedro Cobas²

¹ Centre for Propulsion Engineering, Cranfield University, College Road, Cranfield, Bedfordshire MK43 0AL, UK

² Empresarios Agrupados Internacional, C/Magallanes, Madrid 28015, Spain

Appl. Sci. 2017, 7(3), 255; https://doi.org/10.3390/app7030255 - 6 Mar 2017

Cited by 41 | Viewed by 9086

Abstract

By 2050, the evolutionary approach to aero engine research may no longer provide meaningful returns on investment, whereas more radical approaches to improving thermal efficiency and reducing emissions might still prove cost effective. One such radical concept is the addition of a secondary [...] Read more.

By 2050, the evolutionary approach to aero engine research may no longer provide meaningful returns on investment, whereas more radical approaches to improving thermal efficiency and reducing emissions might still prove cost effective. One such radical concept is the addition of a secondary power cycle that utilizes the otherwise largely wasted residual heat in the core engine’s exhaust gases. This could provide additional shaft power. Supercritical carbon dioxide closed-circuit power cycles are currently being investigated primarily for stationary power applications, but their high power density and efficiency, even for modest peak cycle temperatures, makes them credible bottoming cycle options for aero engine applications. Through individual geometric design and performance studies for each of the bottoming cycle’s major components, it was determined that a simple combined cycle aero engine could offer a 1.9% mission fuel burn benefit over a state-of-the-art geared turbofan for the year 2050. However, the even greater potential of more complex systems demands further investigation. For example, adding inter-turbine reheat (ITR) to the combined cycle is predicted to significantly improve the fuel burn benefit. Full article

(This article belongs to the Special Issue Gas Turbines Propulsion and Power)

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9 pages, 1275 KiB

Open AccessArticle

Understanding Hydrothermal Dechlorination of PVC by Focusing on the Operating Conditions and Hydrochar Characteristics

by Tian Li¹

, Peitao Zhao^1,2,*

, Meng Lei³ and Zhaozhi Li¹

¹ School of Electrical and Power Engineering, China University of Mining and Technology, Xuzhou 221116, China

² National Engineering Research Center for Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, China

³ School of Information and Control Engineering, China University of Mining and Technology, Xuzhou 221116, China

Appl. Sci. 2017, 7(3), 256; https://doi.org/10.3390/app7030256 - 6 Mar 2017

Cited by 57 | Viewed by 9344

Abstract

To remove chlorine from chlorinated wastes efficiently, the hydrothermal treatment (HT) of PVC was investigated with a lower alkaline dosage in this work. Some typical operating conditions were investigated to find out the most important factor affecting the dechlorination efficiency (DE). The FTIR [...] Read more.

To remove chlorine from chlorinated wastes efficiently, the hydrothermal treatment (HT) of PVC was investigated with a lower alkaline dosage in this work. Some typical operating conditions were investigated to find out the most important factor affecting the dechlorination efficiency (DE). The FTIR technique was employed to detect the functional groups in PVC and hydrochars generated to reveal the possible pathways for chlorine removal. The results show that the HT temperature was a key parameter to control the dechlorination reaction rate. At a HT temperature of 240 °C, about 94.3% of chlorine could be removed from the PVC with 1% NaOH. The usage of NaOH was helpful for chlorine removal, while a higher dosage might also hinder this process because of the surface poisoning and coverage of free sites. To some extent, the DE was increased with the residence time. At a residence time of 30 min, the DE reached a maximum of 76.74%. A longer residence time could promote the generation of pores in hydrochar which is responsible for the reduction in DE because of the re-absorption of water-soluble chlorine. According to the FTIR results, the peak intensities of both C=CH and C=C stretching vibrations in hydrochar were increased, while the peak at around 3300 cm⁻¹ representing the –OH group was not obvious, indicating that the dehydrochlorination (elimination reaction) was a main route for chlorine removal under these conditions studied in this work. Full article

(This article belongs to the Section Energy Science and Technology)

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9 pages, 1105 KiB

Open AccessArticle

Global Synchronization of Multichannel EEG Based on Rényi Entropy in Children with Autism Spectrum Disorder

by Junxia Han^1,2, Yanzhu Li³, Jiannan Kang^4,5, Erjuan Cai³, Zhen Tong³, Gaoxiang Ouyang^1,2,*

and Xiaoli Li^1,2,*

¹ State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China

² Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing 100875, China

³ Institute of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China

⁴ College of Electronic & Information Engineering, Hebei University, Baoding 071002, China

⁵ Key Laboratory of Digital Medical Engineering of Hebei Province, Baoding 071002, China

Appl. Sci. 2017, 7(3), 257; https://doi.org/10.3390/app7030257 - 6 Mar 2017

Cited by 14 | Viewed by 5097

Abstract

Autism spectrum disorder (ASD) has been defined as a pervasive neurodevelopmental disorder, involving communication, social interaction and repetitive behaviors. Currently, it is still challenging to understand the differences of brain activity between ASD and healthy children. In this study, we propose calculating the [...] Read more.

Autism spectrum disorder (ASD) has been defined as a pervasive neurodevelopmental disorder, involving communication, social interaction and repetitive behaviors. Currently, it is still challenging to understand the differences of brain activity between ASD and healthy children. In this study, we propose calculating the Rényi entropy of the eigenvalues derived from the signal correlation matrix to measure the global synchronization in multichannel electroencephalograph (EEG) from 16 children with ASD (aged 8–12 years) and 16 age‐ and sex‐matched healthy controls at the resting state. The results indicate that there is a significantly diminished global synchronization from ASD to healthy control. The proposed method can help to reveal the intrinsic characteristics of multichannel EEG signals in children with ASD and aspects that distinguish them from healthy children. Full article

(This article belongs to the Special Issue Application of Signal Processing Methods for Systematic Analysis of Physiological Health)

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14 pages, 3663 KiB

Open AccessArticle

Interactive Rhythm Learning System by Combining Tablet Computers and Robots

by Chien-Hsing Chou^*

and Yung-Long Chu

Department of Electrical Engineering, Tamkang University, New Taipei City 25137, Taiwan

Appl. Sci. 2017, 7(3), 258; https://doi.org/10.3390/app7030258 - 7 Mar 2017

Cited by 5 | Viewed by 4603

Abstract

This study proposes a percussion learning device that combines tablet computers and robots. This device comprises two systems: a rhythm teaching system, in which users can compose and practice rhythms by using a tablet computer, and a robot performance system. First, teachers compose [...] Read more.

This study proposes a percussion learning device that combines tablet computers and robots. This device comprises two systems: a rhythm teaching system, in which users can compose and practice rhythms by using a tablet computer, and a robot performance system. First, teachers compose the rhythm training contents on the tablet computer. Then, the learners practice these percussion exercises by using the tablet computer and a small drum set. The teaching system provides a new and user-friendly score editing interface for composing a rhythm exercise. It also provides a rhythm rating function to facilitate percussion training for children and improve the stability of rhythmic beating. To encourage children to practice percussion exercises, a robotic performance system is used to interact with the children; this system can perform percussion exercises for students to listen to and then help them practice the exercise. This interaction enhances children’s interest and motivation to learn and practice rhythm exercises. The results of experimental course and field trials reveal that the proposed system not only increases students’ interest and efficiency in learning but also helps them in understanding musical rhythms through interaction and composing simple rhythms. Full article

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21 pages, 17790 KiB

Open AccessArticle

Coupled Effect of Expansion Ratio and Blade Loading on the Aerodynamics of a High-Pressure Gas Turbine

by Paolo Gaetani^*, Giacomo Persico

and Andrea Spinelli

Laboratorio di Fluidodinamica delle Macchine, Energy Department Politecnico di Milano, Via Lambruschini, 4, 20158 Milano, Italy

Appl. Sci. 2017, 7(3), 259; https://doi.org/10.3390/app7030259 - 7 Mar 2017

Cited by 25 | Viewed by 6060

Abstract

The need of a continuous improvement in gas turbine efficiency for propulsion and power generation, as well as the more demanding operating conditions and power control required to these machines, still ask for great efforts in the design and analysis of the high [...] Read more.

The need of a continuous improvement in gas turbine efficiency for propulsion and power generation, as well as the more demanding operating conditions and power control required to these machines, still ask for great efforts in the design and analysis of the high pressure section of the turbo-expander. To get detailed insights and improve the comprehension of the flow physics, a wide experimental campaign has been performed in the last ten years at Politecnico di Milano on the unsteady aerodynamics of a high-pressure turbine stage considering several operating conditions. This paper presents and discusses the experimental results obtained for the stage operating with different expansion ratios and rotor loading. The turbine stage under study is representative of a modern high-pressure turbine and can be operated in both subsonic and transonic conditions. The experimental tools applied for the current research represents the state of the art when unsteady investigations are foreseen. The detailed flow field, the blade–rows interaction and the overall performance are described and discussed; efforts have been devoted to the discussion of the various contribution to the overall stage efficiency. The direct effects of the expansion ratio, affecting the Reynolds and the Mach numbers, have been highlighted and quantified; similarly, the indirect effects, accounting for a change in the rotor loading, have been commented and quantified as well, thanks to a dedicated set of experiments where different rotor loadings at the same expansion ratio have been prescribed. Full article

(This article belongs to the Special Issue Gas Turbines Propulsion and Power)

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23 pages, 5645 KiB

Open AccessArticle

An IoT System for Remote Monitoring of Patients at Home

by KeeHyun Park^*, Joonsuu Park and JongWhi Lee

Computer Engineering Department, Keimyung University, Daegu, 42601, Korea

Appl. Sci. 2017, 7(3), 260; https://doi.org/10.3390/app7030260 - 8 Mar 2017

Cited by 54 | Viewed by 9855

Abstract

Application areas that utilize the concept of IoT can be broadened to healthcare or remote monitoring areas. In this paper, a remote monitoring system for patients at home in IoT environments is proposed, constructed, and evaluated through several experiments. To make it operable [...] Read more.

Application areas that utilize the concept of IoT can be broadened to healthcare or remote monitoring areas. In this paper, a remote monitoring system for patients at home in IoT environments is proposed, constructed, and evaluated through several experiments. To make it operable in IoT environments, a protocol conversion scheme between ISO/IEEE 11073 protocol and oneM2M protocol, and a Multiclass Q-learning scheduling algorithm based on the urgency of biomedical data delivery to medical staff are proposed. In addition, for the sake of patients’ privacy, two security schemes are proposed—the separate storage scheme of data in parts and the Buddy-ACK authorization scheme. The experiment on the constructed system showed that the system worked well and the Multiclass Q-learning scheduling algorithm performs better than the Multiclass Based Dynamic Priority scheduling algorithm. We also found that the throughputs of the Multiclass Q-learning scheduling algorithm increase almost linearly as the measurement time increases, whereas the throughputs of the Multiclass Based Dynamic Priority algorithm increase with decreases in the increasing ratio. Full article

(This article belongs to the Special Issue Smart Healthcare)

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14 pages, 6593 KiB

Open AccessArticle

The Effect of EN Ratio and Current on Microstructural and Mechanical Properties of Weld Joined by AC-GMAW on Square Groove Butt Joints

by Adeel Ikram and Hyun Chung^*

Department of Mechanical Engineering, KAIST 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Korea

Appl. Sci. 2017, 7(3), 261; https://doi.org/10.3390/app7030261 - 7 Mar 2017

Cited by 7 | Viewed by 8629

Abstract

In the present work, the effect of welding current and electrode negative (EN) ratio on microstructure and mechanical properties of square groove butt joint produced by alternating current gas metal arc welding (AC-GMAW) process has been investigated. The experiments were conducted using different [...] Read more.

In the present work, the effect of welding current and electrode negative (EN) ratio on microstructure and mechanical properties of square groove butt joint produced by alternating current gas metal arc welding (AC-GMAW) process has been investigated. The experiments were conducted using different combination of welding current ranging from 150 A to 250 A with three distinct EN ratios i.e., 0%, 30% and 50% on 5 mm thick steel plates at a constant joint gap of 1 mm and welding speed of 10 mm/s. The effect of current and EN ratio on welding soundness was evaluated through optical microscopy, tensile tests and micro-hardness mapping. The results revealed that, at higher values of currents, an increase in EN ratio resulted an increase in penetration depth. It was found that at a current of 250 A and a 50% EN ratio, the deep penetration was obtained. Tensile test results showed that the tensile strength properties improved with increasing current. Furthermore, the micro-hardness distribution was not strikingly affected by changing the EN ratio. Full article

(This article belongs to the Special Issue Gas Metal Arc Welding)

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13 pages, 7772 KiB

Open AccessArticle

Application of Electrical Resistivity Data Sets for the Evaluation of the Pollution Concentration Level within Landfill Subsoil

by Eugeniusz Koda¹

, Andrzej Tkaczyk², Mariusz Lech¹ and Piotr Osiński^1,*

¹ Faculty of Civil and Environmental Engineering, Warsaw University of Life Sciences, 02-787 Warsaw, Poland

² Division of Geophysical investigation, GEOTEKO Geotechnical Consultants Ltd., 02-739 Warsaw, Poland

Appl. Sci. 2017, 7(3), 262; https://doi.org/10.3390/app7030262 - 9 Mar 2017

Cited by 34 | Viewed by 7742

Abstract

The paper presents complex analyses of geophysical site investigation results. The electrical resistivity method was used to investigate the potential pollutant migration pathways within areas of existing and former landfill sites. For the purpose of the present study, there were four municipal waste [...] Read more.

The paper presents complex analyses of geophysical site investigation results. The electrical resistivity method was used to investigate the potential pollutant migration pathways within areas of existing and former landfill sites. For the purpose of the present study, there were four municipal waste landfills and one industrial landfill chosen for further comprehensive analyses. The landfill bottom was isolated using geomembrane liner. However, ground water monitoring results revealed that the base was not leakage-free. Another two landfills were established in the past, when no containment systems were legally required. The geoelectrical investigation was the final part of an overall analytical assessment of the contaminated sites. The study was aimed at pollution spatial migration analyses and the interpretation of results, for further design of the reclamation and restoration plans. A clear correlation between pollution indicators such as salt compounds and electrical resistivity, allow aerial analyses and the precise determination of contaminated zones. The research results presented in the paper have been recently obtained and concern a period from 2010 to 2015. Full article

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12 pages, 4941 KiB

Open AccessArticle

In Situ Measurement of Alkali Metals in an MSW Incinerator Using a Spontaneous Emission Spectrum

by Weijie Yan^1,*, Chun Lou^2,*

, Qiang Cheng², Peitao Zhao¹ and Xiangyu Zhang³

¹ School of Electrical and Power Engineering, China University of Mining and Technology, No. 1, Daxue Road, Xuzhou 221116, Jiangsu, China

² State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074, Hubei, China

³ National Engineering Research Center of Clean Coal Combustion, Xi’an Thermal Power Research Institute Co., Ltd, No. 136, Xingqing Road, Xi’an 710032, Shanxi, China

Appl. Sci. 2017, 7(3), 263; https://doi.org/10.3390/app7030263 - 9 Mar 2017

Cited by 35 | Viewed by 5788

Abstract

This paper presents experimental investigations of the in situ diagnosis of the alkali metals in the municipal solid waste (MSW) flame of an industrial grade incinerator using flame emission spectroscopy. The spectral radiation intensities of the MSW flame were obtained using a spectrometer. [...] Read more.

This paper presents experimental investigations of the in situ diagnosis of the alkali metals in the municipal solid waste (MSW) flame of an industrial grade incinerator using flame emission spectroscopy. The spectral radiation intensities of the MSW flame were obtained using a spectrometer. A linear polynomial fitting method is proposed to uncouple the continuous spectrum and the characteristic line. Based on spectra processing and a non-gray emissivity model, the flame temperature, emissivity, and intensities of the emission of alkali metals were calculated by means of measuring the spectral radiation intensities of the MSW flame. Experimental results indicate that the MSW flame contains alkali metals, including Na, K, and even Rb, and it demonstrates non-gray characteristics in a wavelength range from 500 nm to 900 nm. Peak intensities of the emission of the alkali metals were found to increase when the primary air was high, and the measured temperature varied in the same way as the primary air. The temperature and peak intensities of the lines of emission of the alkali metals may be used to adjust the primary airflow and to manage the feeding of the MSW to control the alkali metals in the MSW flame. It was found that the peak intensity of the K emission line had a linear relationship with the peak intensity of the Na emission line; this correlation may be attributed to their similar physicochemical characteristics in the MSW. The variation trend of the emissivity of the MSW flame and the oxygen content in the flue gas were almost opposite because the increased oxygen content suppressed soot formation and decreased soot emissivity. These results prove that the flame emission spectroscopy technique is feasible for monitoring combustion in the MSW incinerator in situ. Full article

(This article belongs to the Special Issue Optics and Spectroscopy for Fluid Characterization)

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10 pages, 370 KiB

Open AccessArticle

Determination of Boron, Phosphorus, and Molybdenum Content in Biosludge Samples by Microwave Plasma Atomic Emission Spectrometry (MP-AES)

by Sreenivasulu Vudagandla¹, Nadavala Siva Kumar^2,*

, Vummiti Dharmendra³, Mohammad Asif², Vysetti Balaram⁴, Haung Zhengxu¹ and Zhou Zhen¹

¹ Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, No. 601 West Huangpu Avenue, Guangzhou 510632, China

² Department of Chemical Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia

³ Agilent Technologies, CP-11, Sector-8, IMT, Manesar, Gurgaon 122 051, India

⁴ Council of Scientific and Industrial Research-National Geophysical Research Institute, Hyderabad 500007, India

Appl. Sci. 2017, 7(3), 264; https://doi.org/10.3390/app7030264 - 8 Mar 2017

Cited by 33 | Viewed by 11227

Abstract

A novel analytical method for accurate determination of boron (B), phosphorous (P), and molybdenum (Mo) content in biosludge samples based on a relatively recent analytical technique, microwave plasma atomic emission spectrometry (MP-AES), is developed in the present work. Microwave assisted acid digestion method [...] Read more.

A novel analytical method for accurate determination of boron (B), phosphorous (P), and molybdenum (Mo) content in biosludge samples based on a relatively recent analytical technique, microwave plasma atomic emission spectrometry (MP-AES), is developed in the present work. Microwave assisted acid digestion method is utilized to extract B, P, and Mo from biosludge. To demonstrate the reliability and accuracy of the present MP-AES method, its results are compared with those obtained using two well-established techniques, i.e., flame atomic absorption spectrometry (FAAS) and inductively coupled plasma optical emission spectrometry (ICP-OES). Matrix variation in the MP-AES technique is found to result in minimal changes. Precision and accuracy of the developed method are demonstrated using replicate analyses of certified sewage sludge reference material, EnviroMAT (BE-1). The limit of quantification and detection of B, P, and Mo in the extracts are determined; the linear regression coefficient was greater than 0.998 for all the three techniques. Analytical wavelengths are selected according to the sensitivity and interference effects. The results obtained in this work demonstrate the potential of MP-AES technique for the determination of B, P, and Mo content in biosludge, which achieved lower detection limits, higher accuracy, and better reproducibility as compared to other techniques. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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28 pages, 4202 KiB

Open AccessFeature PaperReview

Optical Parametric Amplification Techniques for the Generation of High-Energy Few-Optical-Cycles IR Pulses for Strong Field Applications

by Anna G. Ciriolo¹, Matteo Negro², Michele Devetta²

, Eugenio Cinquanta¹, Davide Faccialà¹, Aditya Pusala¹, Sandro De Silvestri^1,2, Salvatore Stagira^1,2

and Caterina Vozzi^2,*

¹ Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy

² Istituto di Fotonica e Nanotecnologie (IFN), CNR, Via Cineto Romano, 42, 00156 Roma, Italy

Appl. Sci. 2017, 7(3), 265; https://doi.org/10.3390/app7030265 - 8 Mar 2017

Cited by 47 | Viewed by 13941

Abstract

Over the last few decades, the investigation of ultrafast phenomena occurring in atoms, molecules and solid-state systems under a strong-field regime of light-matter interaction has attracted great attention. The increasing request for a suitable optical technology is significantly boosting the development of powerful [...] Read more.

Over the last few decades, the investigation of ultrafast phenomena occurring in atoms, molecules and solid-state systems under a strong-field regime of light-matter interaction has attracted great attention. The increasing request for a suitable optical technology is significantly boosting the development of powerful ultrafast laser sources. In this framework, Optical Parametric Amplification (OPA) is currently becoming a leading solution for applications in high-power ultra-broadband light burst generation. The main advantage provided by the OPA scheme consists of the possibility of exploring spectral ranges that are inaccessible by other laser technologies, as the InfraRed (IR) window. In this paper, we will give an overview on recent progress in the development of high-power few-optical-cycle parametric amplifiers in the near-IR and in the mid-IR spectral domain. In particular, the design of the most advanced OPA implementations is provided, containing a discussion on the key technical aspects. In addition, a review on their application to the study of strong-field ultrafast physical processes is reported. Full article

(This article belongs to the Special Issue Ultrashort Optical Pulses)

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17 pages, 2567 KiB

Open AccessArticle

Robust and Agile System against Fault and Anomaly Traffic in Software Defined Networks

by Mihui Kim¹

, Younghee Park^2,* and Rohit Kotalwar²

¹ Department of Computer Science & Engineering, Computer System Institute, Hankyong National University/327, Jungang-ro, Anseong-si, Gyeonggi-do 17579, Korea

² Computer Engineering Department, San Jose State University, One Washington Square, San Jose, CA 95192, USA

Appl. Sci. 2017, 7(3), 266; https://doi.org/10.3390/app7030266 - 8 Mar 2017

Cited by 9 | Viewed by 5001

Abstract

The main advantage of software defined networking (SDN) is that it allows intelligent control and management of networking though programmability in real time. It enables efficient utilization of network resources through traffic engineering, and offers potential attack defense methods when abnormalities arise. However, [...] Read more.

The main advantage of software defined networking (SDN) is that it allows intelligent control and management of networking though programmability in real time. It enables efficient utilization of network resources through traffic engineering, and offers potential attack defense methods when abnormalities arise. However, previous studies have only identified individual solutions for respective problems, instead of finding a more global solution in real time that is capable of addressing multiple situations in network status. To cover diverse network conditions, this paper presents a comprehensive reactive system for simultaneously monitoring failures, anomalies, and attacks for high availability and reliability. We design three main modules in the SDN controller for a robust and agile defense (RAD) system against network anomalies: a traffic analyzer, a traffic engineer, and a rule manager. RAD provides reactive flow rule generation to control traffic while detecting network failures, anomalies, high traffic volume (elephant flows), and attacks. The traffic analyzer identifies elephant flows, traffic anomalies, and attacks based on attack signatures and network monitoring. The traffic engineer module measures network utilization and delay in order to determine the best path for multi-dimensional routing and load balancing under any circumstances. Finally, the rule manager generates and installs a flow rule for the selected best path to control traffic. We implement the proposed RAD system based on Floodlight, an open source project for the SDN controller. We evaluate our system using simulation with and without the aforementioned RAD modules. Experimental results show that our approach is both practical and feasible, and can successfully augment an existing SDN controller in terms of agility, robustness, and efficiency, even in the face of link failures, attacks, and elephant flows. Full article

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13 pages, 4145 KiB

Open AccessArticle

Numerical and Experimental Study on Enhancing Performance of the Stand Fan

by Sheam-Chyun Lin^1,*

, Ming-Chiou Shen²

, Hao-Ru Tso¹, Hung-Cheng Yen³ and Yu-Cheng Chen¹

¹ Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan

² Department of Mechanical Engineering, Far East University, Tainan 74448, Taiwan

³ Industrial Technology Research Institute, Hsinchu 31040, Taiwan

Appl. Sci. 2017, 7(3), 267; https://doi.org/10.3390/app7030267 - 8 Mar 2017

Cited by 8 | Viewed by 8026

Abstract

To meet humans’ need of enhancing the quality of life, the high-performance stand fan has become an essential appliance in every family. On the other hand, energy saving can not only solve the problem of environment protection, but also can reduce the cost [...] Read more.

To meet humans’ need of enhancing the quality of life, the high-performance stand fan has become an essential appliance in every family. On the other hand, energy saving can not only solve the problem of environment protection, but also can reduce the cost of energy consumption. However, the aerodynamic performance and flow characteristics of the stand fan are rarely investigated and analyzed in a systematical manner. Therefore, this research intends to investigate the physical mechanism of the flow pattern and identify the design parameters of the stand fan by combining numerical and experimental methods. First of all, both the structure and performance of a commercial 14-inch stand fan are chosen for analysis and are set as the reference for the fan. The stand fan can be divided into the impeller and the protective cover. Clearly, the impeller blades have a great influence on the fan performance, so they are the first design target. In this work, CFD (computational fluid dynamics) software Fluent (version 14.5, ANSYS Inc., Canonsburg, PA, USA, 2012) is used to analyze and observe the corresponding influences on flow fields and aerodynamic performance by changing the design parameters such as the setting, twist, and inclination angles. Then, the protective cover is studied, improved and integrated with the designed impeller to further enhance the performance of the fan. The protective cover is modified by varying the spacing between the blade tip and cover, as well as varying the shape and angle of ribs to improve the fan’s flow field and performance. Finally, the optimal fan mockup is made via CNC (computer numerical control) technology. Also, its acoustics and performance have been measured to validate the accuracy and reliability of the numerical simulation. The testing results show that the optimally designed stand fan is better than the reference fan with a significant 54% increase in max flow rate. In addition, it has more uniform velocity distribution compared with the reference fan to achieve a comfortable feeling for the human body. In summary, this research successfully establishes a reliable and systematic scheme to design the stand fan. Also, the corresponding performance influences caused by those important parameters are analyzed and summarized to serve as the design reference for the stand fan. Full article

(This article belongs to the Special Issue Selected Papers from the International Multi-Conference on Engineering and Technology Innovation 2015 (IMETI2015))

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16 pages, 4573 KiB

Open AccessArticle

Hyperspectral Imaging as a Rapid Quality Control Method for Herbal Tea Blends

by Majolie Djokam¹, Maxleene Sandasi¹, Weiyang Chen¹, Alvaro Viljoen^1,2 and Ilze Vermaak^1,2,*

¹ Department of Pharmaceutical Sciences, Faculty of Science, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa

² SAMRC Herbal Drugs Research Unit, Faculty of Science, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa

Appl. Sci. 2017, 7(3), 268; https://doi.org/10.3390/app7030268 - 8 Mar 2017

Cited by 35 | Viewed by 8213

Abstract

In South Africa, indigenous herbal teas are enjoyed due to their distinct taste and aroma. The acclaimed health benefits of herbal teas include the management of chronic diseases such as hypertension and diabetes. Quality control of herbal teas has become important due to [...] Read more.

In South Africa, indigenous herbal teas are enjoyed due to their distinct taste and aroma. The acclaimed health benefits of herbal teas include the management of chronic diseases such as hypertension and diabetes. Quality control of herbal teas has become important due to the availability of different brands of varying quality and the production of tea blends. The potential of hyperspectral imaging as a rapid quality control method for herbal tea blends from rooibos (Aspalathus linearis), honeybush (Cyclopia intermedia), buchu (Agathosma Betulina) and cancerbush (Sutherlandia frutescens) was investigated. Hyperspectral images of raw materials and intact tea bags were acquired using a sisuChema shortwave infrared (SWIR) hyperspectral pushbroom imaging system (920–2514 nm). Principal component analysis (PCA) plots showed clear discrimination between raw materials. Partial least squares discriminant analysis (PLS-DA) models correctly predicted the raw material constituents of each blend and accurately determined the relative proportions. The results were corroborated independently using ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS). This study demonstrated the application of hyperspectral imaging coupled with chemometric modelling as a reliable, rapid and non-destructive quality control method for authenticating herbal tea blends and to determine relative proportions in a tea bag. Full article

(This article belongs to the Special Issue Applications of Hyperspectral Imaging for Food and Agriculture)

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19 pages, 1911 KiB

Open AccessArticle

Researching a Fuzzy- and Performance-Based Optimization Method for the Life-Cycle Cost of SRHPC Frame Structures

by Jie Zheng¹, Li-guo Dong², Shan-suo Zheng^2,*, Lei Zeng³, Ze-hui Xiang² and Wei He²

¹ Architectural Design Institute, Xi’an University of Architecture and Technology, Xi’an 710055, China

² School of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China

³ School of Urban Construction, Yangtze University, Jingzhou 434023, China

Appl. Sci. 2017, 7(3), 269; https://doi.org/10.3390/app7030269 - 8 Mar 2017

Cited by 6 | Viewed by 3976

Abstract

In order to solve two problems with the traditional optimization method of steel reinforced high strength high performance concrete (SRHPC) frame structures, a fuzzy mathematics and performance-based optimization method for the life-cycle cost of SRHPC frame structures is proposed. In the optimization program, [...] Read more.

In order to solve two problems with the traditional optimization method of steel reinforced high strength high performance concrete (SRHPC) frame structures, a fuzzy mathematics and performance-based optimization method for the life-cycle cost of SRHPC frame structures is proposed. In the optimization program, quantitative seismic performance indicators of SRHPC frame structures are determined according to the experimental results of SRHPC columns. Furthermore, by considering the fuzzy reliability of structures under each performance level, the life-cycle optimization model of SRHPC frame structures can be established. In order to solve the problem of too many variables and constraints in the optimization process, a two-step optimization method is proposed. Finally, an optimization example is carried out through the MATLAB program to demonstrate the feasibility of this model. Full article

(This article belongs to the Special Issue Structural Health Monitoring (SHM) of Civil Structures)

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20 pages, 2909 KiB

Open AccessArticle

Theory of Regions for Control Synthesis without Computing Reachability Graph

by Sadok Rezig^1,*

, Zied Achour¹ and Nidhal Rezg^1,2

¹ Laboratoire de Génie Industriel, de Production et de Maintenance (LGIPM), Université de Lorraine, UFR MIM, île du Saulcy–BP 50128, 57045 Metz, France

² ICN Business School, 54003 Metz-Nancy, France

Appl. Sci. 2017, 7(3), 270; https://doi.org/10.3390/app7030270 - 9 Mar 2017

Cited by 6 | Viewed by 4615

Abstract

This paper addresses the design of Petri net (PN) supervisor using the theory of regions for forbidden state problem with a set of general mutual exclusion constraints. In fact, as any method of supervisory control based on reachability graph, the theory of regions [...] Read more.

This paper addresses the design of Petri net (PN) supervisor using the theory of regions for forbidden state problem with a set of general mutual exclusion constraints. In fact, as any method of supervisory control based on reachability graph, the theory of regions suffers from a technical obstacle in control synthesis, which is the necessity of computing the graph at each iteration step. Moreover, based on the reachability graph, which may contain a large number of states, with respect to the structural size of the system, the computation of PN controllers becomes harder and even impossible. The main contribution of this paper, compared to previous works, is the development of a control synthesis method in order to decrease significantly the computation cost of the PN supervisor. Thus, based on PN properties and mathematical concepts, the proposed methodology provides an optimal PN supervisor for bounded Petri nets following the interpretation of the theory of regions. Finally, case studies are solved by CPLEX software to compare our new control policy with previous works which use the theory of regions for control synthesis. Full article

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25 pages, 762 KiB

Open AccessArticle

Magnetohydrodynamic Nanoliquid Thin Film Sprayed on a Stretching Cylinder with Heat Transfer

by Noor Saeed Khan¹

, Taza Gul^1,*

, Saeed Islam¹

, Ilyas Khan²

, Aisha M. Alqahtani³

and Ali Saleh Alshomrani⁴

¹ Department of Mathematics, Abdul Wali Khan University, Mardan 32300, Khyber Pakhtunkhwa, Pakistan

² Basic Engineering Sciences Department, College of Engineering, Majmaah University, Majmaah 11952, Saudi Arabia

³ Department of Mathematics, Princess Nourah bint Abdulrahman University, Riyadh 11564, Saudi Arabia

⁴ Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah, 21577, Saudi Arabia

Appl. Sci. 2017, 7(3), 271; https://doi.org/10.3390/app7030271 - 10 Mar 2017

Cited by 153 | Viewed by 7340

Abstract

The magnetohydrodynamic thin film nanofluid sprayed on a stretching cylinder with heat transfer is explored. The spray rate is a function of film size. Constant reference temperature is used for the motion past an expanding cylinder. The sundry behavior of the magnetic nano [...] Read more.

The magnetohydrodynamic thin film nanofluid sprayed on a stretching cylinder with heat transfer is explored. The spray rate is a function of film size. Constant reference temperature is used for the motion past an expanding cylinder. The sundry behavior of the magnetic nano liquid thin film is carefully noticed which results in to bring changes in the flow pattern and heat transfer. Water-based nanofluids like Al

_{2}

O

_{3}

-H

_{2}

O and CuO-H

_{2}

O are investigated under the consideration of thin film. The basic constitutive equations for the motion and transfer of heat of the nanofluid with the boundary conditions have been converted to nonlinear coupled differential equations with physical conditions by employing appropriate similarity transformations. The modeled equations have been computed by using HAM (Homotopy Analysis Method) and lead to detailed expressions for the velocity profile and temperature distribution. The pressure distribution and spray rate are also calculated. The comparison of HAM solution predicts the close agreement with the numerical method solution. The residual errors show the authentication of the present work. The CuO-H

_{2}

O nanofluid results from this study are compared with the experimental results reported in the literature showing high accuracy especially, in investigating skin friction coefficient and Nusselt number. The present work discusses the salient features of all the indispensable parameters of spray rate, velocity profile, temperature and pressure distributions which have been displayed graphically and illustrated. Full article

(This article belongs to the Special Issue Recent Developments of Nanofluids)

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19 pages, 1933 KiB

Open AccessArticle

Self-Fitting Algorithm for Digital Hearing Aid Based on Interactive Evolutionary Computation and Expert System

by Ruiyu Liang^1,2,*

, Ruxue Guo¹

, Ji Xi^1,3, Yue Xie¹ and Li Zhao¹

¹ School of Information Science and Engineering, Southeast University, Nanjing 210096, China

² School of Communication Engineering, Nanjing Institute of Technology, Nanjing 211167, China

³ School of Computer Information and Engineering, Changzhou Institute of Technology, Changzhou 213002, China

Appl. Sci. 2017, 7(3), 272; https://doi.org/10.3390/app7030272 - 9 Mar 2017

Cited by 17 | Viewed by 7180

Abstract

The traditional hearing aid fitting method, which mainly relies on the audiologist, is timeconsuming and messy. To improve this situation, a self-fitting algorithm based on an improved interactive evolutionary computation (IEC) algorithm and expert system, which enables the patients to fit the hearing [...] Read more.

The traditional hearing aid fitting method, which mainly relies on the audiologist, is timeconsuming and messy. To improve this situation, a self-fitting algorithm based on an improved interactive evolutionary computation (IEC) algorithm and expert system, which enables the patients to fit the hearing aid by themselves, is proposed. The algorithm takes the band gain as the fitting target and uses the patient’s subjective evaluation to iteratively update the algorithm parameters based on the improved IEC algorithm. In addition, a real-time updated expert system is constructed to assist in the optimization of the initial and iterative parameters of the fitting based on the patient’s audiogram and personal information. To verify the performance of the algorithm, a self-fitting software for the hearing aid is designed. Through this software, the test signal is generated for the patient to evaluate the audio quality on a five-level scale. Based on the evaluation results, the algorithm iteratively optimizes the algorithm parameters until the patient is satisfied with the generated audio. Compared with the fitting algorithm based on Gaussian processes algorithm or the interactive evolutionary algorithm, the average subjective speech recognition rate of the proposed algorithm increase at least 11%. The average recognition rate for environmental sound is also improved by at least 2.9%. In addition, the fitting time of the proposed algorithm is shortened by at least 10 min compared to others two algorithms. Full article

(This article belongs to the Section Acoustics and Vibrations)

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10 pages, 2210 KiB

Open AccessArticle

Aqueous-Organic Phase Transfer of Gold and Silver Nanoparticles Using Thiol-Modified Oleic Acid

by Alejandra López-Millán¹, Paul Zavala-Rivera²

, Reynaldo Esquivel¹, Roberto Carrillo¹

, Enrique Alvarez-Ramos¹, Ramón Moreno-Corral³, Roberto Guzmán-Zamudio⁴ and Armando Lucero-Acuña^2,*

¹ Nanotechnology Graduate Program, Department of Physics, University of Sonora, Hermosillo 83000, Sonora, Mexico

² Department of Chemical and Metallurgical Engineering, University of Sonora, Hermosillo 83000, Sonora, Mexico

³ Department of Polymers and Materials Research, University of Sonora, Hermosillo 83000, Sonora, Mexico

⁴ Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA

Appl. Sci. 2017, 7(3), 273; https://doi.org/10.3390/app7030273 - 9 Mar 2017

Cited by 20 | Viewed by 7658

Abstract

The handling of metallic nanoparticles often requires their dispersion into several polar and nonpolar solvents. Solid-phase stages or polymer-based ligands are commonly required to complete the transfer. The construction of a thiol ligand based in oleic acid, and its ability to efficiently assist [...] Read more.

The handling of metallic nanoparticles often requires their dispersion into several polar and nonpolar solvents. Solid-phase stages or polymer-based ligands are commonly required to complete the transfer. The construction of a thiol ligand based in oleic acid, and its ability to efficiently assist in gold and silver nanoparticle aqueous–organic phase transfer is reported. After the transfer, the particles are completely dispersed in an organic solvent, preserving their diameter and morphology, as confirmed by ultraviolet–visible spectroscopy and scanning transmission electron micrographs. Full article

(This article belongs to the Section Nanotechnology and Applied Nanosciences)

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10 pages, 1219 KiB

Open AccessArticle

Gear Wear Process Monitoring Using a Sideband Estimator Based on Modulation Signal Bispectrum

by Ruiliang Zhang¹, Xi Gu^2,*, Fengshou Gu^1,3

, Tie Wang¹

and Andrew D. Ball³

¹ School of Mechanical Engineering, Taiyuan University of Technology, Taiyuan 030024, China

² School of Electronic Engineering, Bangor College Changsha, Central South University of Forestry and Technology, Changsha 410004, China

³ Centre for Efficiency and Performance Engineering, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK

Appl. Sci. 2017, 7(3), 274; https://doi.org/10.3390/app7030274 - 10 Mar 2017

Cited by 37 | Viewed by 6366

Abstract

As one of the most common gear failure modes, tooth wear can produce nonlinear modulation sidebands in the vibration frequency spectrum. However, limited research has been reported in monitoring the gear wear based on vibration due to the lack of tools which can [...] Read more.

As one of the most common gear failure modes, tooth wear can produce nonlinear modulation sidebands in the vibration frequency spectrum. However, limited research has been reported in monitoring the gear wear based on vibration due to the lack of tools which can effectively extract the small sidebands. In order to accurately monitor gear wear progression in a timely fashion, this paper presents a gear wear condition monitoring approach based on vibration signal analysis using the modulation signal bispectrum-based sideband estimator (MSB-SE) method. The vibration signals are collected using a run-to-failure test of gearbox under an accelerated test process. MSB analysis was performed on the vibration signals to extract the sideband information. Using a combination of the peak value of MSB-SE and the coherence of MSB-SE, the overall information of gear transmission system can be obtained. Based on the amplitude of MSB-SE peaks, a dimensionless indicator is proposed to assess the effects of gear tooth wear. The results demonstrated that the proposed indicator can be used to accurately and reliably monitor gear tooth wear and evaluate the wear severity. Full article

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11 pages, 17980 KiB

Open AccessArticle

A Comparative Study of Additively Manufactured Thin Wall and Block Structure with Al-6.3%Cu Alloy Using Cold Metal Transfer Process

by Baoqiang Cong^1,2, Zewu Qi^1,2, Bojin Qi^1,2,*, Hongye Sun^1,2, Gang Zhao^1,2 and Jialuo Ding³

¹ School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China

² MIIT Key Laboratory of Aeronautics Intelligent Manufacturing, Beijing 100191, China

³ Welding Engineering and Laser Processing Centre, Cranfield University, Cranfield MK43 0AL, UK

Appl. Sci. 2017, 7(3), 275; https://doi.org/10.3390/app7030275 - 10 Mar 2017

Cited by 162 | Viewed by 12923

Abstract

In order to build a better understanding of the relationship between depositing mode and porosity, microstructure, and properties in wire + arc additive manufacturing (WAAM) 2319-Al components, several Al-6.3%Cu deposits were produced by WAAM technique with cold metal transfer (CMT) variants, pulsed CMT [...] Read more.

In order to build a better understanding of the relationship between depositing mode and porosity, microstructure, and properties in wire + arc additive manufacturing (WAAM) 2319-Al components, several Al-6.3%Cu deposits were produced by WAAM technique with cold metal transfer (CMT) variants, pulsed CMT (CMT-P) and advanced CMT (CMT-ADV). Thin walls and blocks were selected as the depositing paths to make WAAM samples. Porosity, microstructure and micro hardness of these WAAM samples were investigated. Compared with CMT-P and thin wall mode, CMT-ADV and block process can effectively reduce the pores in WAAM aluminum alloy. The microstructure varied with different depositing paths and CMT variants. The micro hardness value of thin wall samples was around 75 HV from the bottom to the middle, and gradually decreased toward the top. Meanwhile, the micro hardness value ranged around 72–77 HV, and varied periodically in block samples. The variation in micro hardness is consistent with standard microstructure characteristics. Full article

(This article belongs to the Special Issue Gas Metal Arc Welding)

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17 pages, 661 KiB

Open AccessReview

Cranioplasty and Craniofacial Reconstruction: A Review of Implant Material, Manufacturing Method and Infection Risk

by Jeremy Kwarcinski¹, Philip Boughton¹

, Andrew Ruys¹, Alessandra Doolan² and James Van Gelder^3,*

¹ Faculty of Engineering and IT, The University of Sydney, Sydney NSW 2006, Australia

² Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia

³ Sydney Spine Institute; Sydney NSW 1805, Australia

Appl. Sci. 2017, 7(3), 276; https://doi.org/10.3390/app7030276 - 10 Mar 2017

Cited by 61 | Viewed by 10659

Abstract

Analysis of current literature highlights a wide variation in reported infection risk for different materials in cranial repair. The purpose of these composite materials are to mimic natural bone and assist in restoring function (structurally and aesthetically) to the human skull. This review [...] Read more.

Analysis of current literature highlights a wide variation in reported infection risk for different materials in cranial repair. The purpose of these composite materials are to mimic natural bone and assist in restoring function (structurally and aesthetically) to the human skull. This review aims to examine the meta-data in order to provide an amalgamated overview of potential trends between implant material, manufacturing method and infection risk, in order to provide a core reference point for future studies surrounding emerging biomedical materials in the fields of cranioplasty by providing base point for understanding the capabilities and limitations of current technologies. Methods: A search for articles was conducted, with the following criteria seen as fundamental in providing an accurate picture of the current landscape: publication in the last decade, provision of a numerical value for both number of implants and infection cases, patient sample of 10+, adult patients, and cranioplasty/cranial repair. Results: A total of 41 articles were seen to meet the author’s inclusion criteria. Average infection rates per material ranged between 2.04% and 10.98%. The results indicate that there is variation between materials in regards to total infection risk, however, depending on the materials compared, this value may be insignificant. Alternative risk factors associated with infection, including surgical time, revisions and previous infection, have a greater impact on infection potential than material variation. Comparison of fabrication methods did highlight a notable effect on average infection rate. Trends can be observed showing that materials with greater levels of surface interaction and active support of tissue ingrowth presented greater infection resistance. Such characteristics are due to the physical structures of the implants. Conclusions: It can be said that the manufacturing methods can influence biomedical materials to assist in minimizing implant infection risk. Full article

(This article belongs to the Special Issue Bio-Inspired Applications of Composites)

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21 pages, 2196 KiB

Open AccessArticle

A Truly Second-Order and Unconditionally Stable Thermal Lattice Boltzmann Method

by Zhen Chen

, Chang Shu^*

and Danielle S. Tan

Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore

Appl. Sci. 2017, 7(3), 277; https://doi.org/10.3390/app7030277 - 11 Mar 2017

Cited by 20 | Viewed by 5137

Abstract

An unconditionally stable thermal lattice Boltzmann method (USTLBM) is proposed in this paper for simulating incompressible thermal flows. In USTLBM, solutions to the macroscopic governing equations that are recovered from lattice Boltzmann equation (LBE) through Chapman–Enskog (C-E) expansion analysis are resolved in a [...] Read more.

An unconditionally stable thermal lattice Boltzmann method (USTLBM) is proposed in this paper for simulating incompressible thermal flows. In USTLBM, solutions to the macroscopic governing equations that are recovered from lattice Boltzmann equation (LBE) through Chapman–Enskog (C-E) expansion analysis are resolved in a predictor–corrector scheme and reconstructed within lattice Boltzmann framework. The development of USTLBM is inspired by the recently proposed simplified thermal lattice Boltzmann method (STLBM). Comparing with STLBM which can only achieve the first-order of accuracy in time, the present USTLBM ensures the second-order of accuracy both in space and in time. Meanwhile, all merits of STLBM are maintained by USTLBM. Specifically, USTLBM directly updates macroscopic variables rather than distribution functions, which greatly saves virtual memories and facilitates implementation of physical boundary conditions. Through von Neumann stability analysis, it can be theoretically proven that USTLBM is unconditionally stable. It is also shown in numerical tests that, comparing to STLBM, lower numerical error can be expected in USTLBM at the same mesh resolution. Four typical numerical examples are presented to demonstrate the robustness of USTLBM and its flexibility on non-uniform and body-fitted meshes. Full article

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20 pages, 3304 KiB

Open AccessArticle

The Reduction of Vertical Interchannel Crosstalk: The Analysis of Localisation Thresholds for Natural Sound Sources

by Rory Wallis

and Hyunkook Lee^*

Applied Psychoacoustics Lab, University of Huddersfield, Huddersfield HD1 3DH, UK

Appl. Sci. 2017, 7(3), 278; https://doi.org/10.3390/app7030278 - 14 Mar 2017

Cited by 13 | Viewed by 6114

Abstract

In subjective listening tests, natural sound sources were presented to subjects as vertically-oriented phantom images from two layers of loudspeakers, ‘height’ and ‘main’. Subjects were required to reduce the amplitude of the height layer until the position of the resultant sound source matched [...] Read more.

In subjective listening tests, natural sound sources were presented to subjects as vertically-oriented phantom images from two layers of loudspeakers, ‘height’ and ‘main’. Subjects were required to reduce the amplitude of the height layer until the position of the resultant sound source matched that of the same source presented from the main layer only (the localisation threshold). Delays of 0, 1 and 10 ms were applied to the height layer with respect to the main, with vertical stereophonic and quadraphonic conditions being tested. The results of the study showed that the localisation thresholds obtained were not significantly affected by sound source or presentation method. Instead, the only variable whose effect was significant was interchannel time difference (ICTD). For ICTD of 0 ms, the median threshold was −9.5 dB, which was significantly lower than the −7 dB found for both 1 and 10 ms. The results of the study have implications both for the recording of sound sources for three-dimensional (3D) audio reproduction formats and also for the rendering of 3D images. Full article

(This article belongs to the Special Issue Spatial Audio)

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12 pages, 4236 KiB

Open AccessArticle

A Finite Element Investigation into the Impact Performance of an Open-Face Motorcycle Helmet with Ventilation Slots

by De-Shin Liu and Yao-Te Chen^*

Department of Mechanical Engineering, Advanced Institute of Manufacturing for High-tech Innovations, National Chung Cheng University, 168 University Rd., Minhsiung, Chiayi 62102, Taiwan

Appl. Sci. 2017, 7(3), 279; https://doi.org/10.3390/app7030279 - 16 Mar 2017

Cited by 12 | Viewed by 8392

Abstract

Motorcycle helmets are essential for reducing the risk of head injuries in the event of an impact. However, during the design of helmets, a compromise must be made between user safety and user comfort. Accordingly, the present study proposes a novel open-face helmet [...] Read more.

Motorcycle helmets are essential for reducing the risk of head injuries in the event of an impact. However, during the design of helmets, a compromise must be made between user safety and user comfort. Accordingly, the present study proposes a novel open-face helmet design, in which the helmet features three ventilation slots in the upper-head region. Finite element analysis (FEA) models were constructed for both a prototype helmet design, and three traditional helmet designs (full-face, open-face, and half-face helmets). In simulating the proposed open-face helmet, this study considered three different ventilation slot widths, namely 8, 14, and 18 mm. The simulation results showed that of all the helmet designs, the half-face helmet resulted in the greatest headform acceleration (303 G). The internal ventilation helmet achieved a lower peak acceleration than that of the full-face helmet. By contrast, the proposed open-face helmet with ventilation slots resulted in the lowest acceleration, irrespective of the ventilation slot width. The 8-mm ventilation slot width resulted in the optimal impact performance level (i.e., a peak headform acceleration of 160 G). Overall, the results suggest that the proposed open-face helmet design with ventilation slots provides a promising solution for ensuring both user protection and user comfort in warm climates. Full article

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18 pages, 658 KiB

Open AccessArticle

A New Engine Fault Diagnosis Method Based on Multi-Sensor Data Fusion

by Wen Jiang^*

, Weiwei Hu and Chunhe Xie

School of Electronics and Information, Northwestern Polytechnical University, Xi’an 710072, Shaanxi, China

Appl. Sci. 2017, 7(3), 280; https://doi.org/10.3390/app7030280 - 14 Mar 2017

Cited by 42 | Viewed by 5449

Abstract

Fault diagnosis is an important research direction in modern industry. In this paper, a new fault diagnosis method based on multi-sensor data fusion is proposed, in which the Dempster–Shafer (D–S) evidence theory is employed to model the uncertainty. Firstly, Gaussian types of fault [...] Read more.

Fault diagnosis is an important research direction in modern industry. In this paper, a new fault diagnosis method based on multi-sensor data fusion is proposed, in which the Dempster–Shafer (D–S) evidence theory is employed to model the uncertainty. Firstly, Gaussian types of fault models and test models are established by observations of sensors. After the models are determined, the intersection area between test model and fault models is transformed into a set of BPAs (basic probability assignments), and a weighted average combination method is used to combine the obtained BPAs. Finally, through some given decision making rules, diagnostic results can be obtained. The proposed method in this paper is tested by the Iris data set and actual measurement data of the motor rotor, which verifies the effectiveness of the proposed method. Full article

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10 pages, 1768 KiB

Open AccessArticle

Optimal Scheduling of Industrial Task-Continuous Load Management for Smart Power Utilization

by Jidong Wang^*

, Kaijie Fang, Jiaqiang Dai, Yuhao Yang and Yue Zhou

Key Laboratory of Smart Grid of Ministry of Education, Tianjin University, Tianjin 300072, China

Appl. Sci. 2017, 7(3), 281; https://doi.org/10.3390/app7030281 - 14 Mar 2017

Cited by 3 | Viewed by 5058

Abstract

In the context of climate change and energy crisis around the world, an increasing amount of attention has been paid to developing clean energy and improving energy efficiency. The penetration of distributed generation (DG) is increasing rapidly on the user’s side of an [...] Read more.

In the context of climate change and energy crisis around the world, an increasing amount of attention has been paid to developing clean energy and improving energy efficiency. The penetration of distributed generation (DG) is increasing rapidly on the user’s side of an increasingly intelligent power system. This paper proposes an optimization method for industrial task-continuous load management in which distributed generation (including photovoltaic systems and wind generation) and energy storage devices are both considered. To begin with, a model of distributed generation and an energy storage device are built. Then, subject to various constraints, an operation optimization problem is formulated to maximize user profit, renewable energy efficiency, and the local consumption of distributed generation. Finally, the effectiveness of the method is verified by comparing user profit under different power modes. Full article

(This article belongs to the Special Issue Advances in Integrated Energy Systems Design, Control and Optimization)

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19 pages, 8382 KiB

Open AccessArticle

Application of a High-Power Reversible Converter in a Hybrid Traction Power Supply System

by Gang Zhang^1,2,*, Jianglin Qian^1,2 and Xinyu Zhang^1,2

¹ School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China

² Beijing Electrical Engineering Technology Research Center, Beijing 100044, China

Appl. Sci. 2017, 7(3), 282; https://doi.org/10.3390/app7030282 - 14 Mar 2017

Cited by 19 | Viewed by 8828

Abstract

A high-power reversible converter can achieve a variety of functions, such as recovering regenerative braking energy, expanding traction power capacity, and improving an alternating current (AC) grid power factor. A new hybrid traction power supply scheme, which consists of a high-power reversible converter [...] Read more.

A high-power reversible converter can achieve a variety of functions, such as recovering regenerative braking energy, expanding traction power capacity, and improving an alternating current (AC) grid power factor. A new hybrid traction power supply scheme, which consists of a high-power reversible converter and two 12-pulse diode rectifiers, is proposed. A droop control method based on load current feed-forward is adopted to realize the load distribution between the reversible converter and the existing 12-pulse diode rectifiers. The direct current (DC) short-circuit characteristics of the reversible converter is studied, then the relationship between the peak fault current and the circuit parameters is obtained from theoretical calculations and validated by computer simulation. The first two sets of 2 MW reversible converters have been successfully applied in Beijing Metro Line 10, the proposed hybrid application scheme and coordinated control strategy are verified, and 11.15% of average energy-savings is reached. Full article

(This article belongs to the Special Issue Energy Saving)

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22 pages, 8637 KiB

Open AccessArticle

Development of a Preliminary Design Method for Subsonic Splittered Blades in Highly Loaded Axial-Flow Compressors

by Baojie Liu^1,2,3, Du Fu¹ and Xianjun Yu^1,2,3,*

¹ School of Energy and Power Engineering, Beihang University, Beijing 100191, China

² National Key Laboratory of Science & Technology on Aero-Engine Aero-Thermodynamics, Beihang University, Beijing 100191, China

³ Collaborative Innovation Center of Advanced Aero-Engine, Beihang University, Beijing 100191, China

Appl. Sci. 2017, 7(3), 283; https://doi.org/10.3390/app7030283 - 14 Mar 2017

Cited by 11 | Viewed by 8633

Abstract

This paper presents a model for predicting the reference minimum-loss incidence and deviation angles of a blade arrangement with splitter vanes, which is probably a solution for future ultra-highly loaded axial compressor designs. The motivation of the modeling is to guide the blading [...] Read more.

This paper presents a model for predicting the reference minimum-loss incidence and deviation angles of a blade arrangement with splitter vanes, which is probably a solution for future ultra-highly loaded axial compressor designs. The motivation of the modeling is to guide the blading design in splittered compressor design processes where the additional splitter vanes must be specially considered. The development of the model is based on a blade performance database from systematic numerical simulations. Basic correlations of the model are firstly proposed, which consider dominant blade geometry parameters related to blade loading, including camber angle and solidity. Secondly, geometric and aerodynamic corrections about orientation parameter, blade maximum thickness, inlet Mach number, and three-dimensional (3D) effects are empirically incorporated into the basic correlations. Eventually, a subsonic 3D splittered rotor is designed using the correlations coupled with the corrections obtained from the validation of the model. The results indicate that the model is able to achieve a good agreement within an error band of ±1.0° for the predictions of both reference minimum-loss incidence and deviation angles, and the rotor designed using the model accomplishes the desired work input and flow deflection. Full article

(This article belongs to the Special Issue Gas Turbines Propulsion and Power)

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13 pages, 1759 KiB

Open AccessArticle

Construction of Compact Finite Difference Schemes by Classic Differential Quadrature

by Fangzong Wang^*, Mingshuai Pan and Yong Wang

College of Electrical Engineering & New Energy, China Three Gorges University, Yichang 443002, China

Appl. Sci. 2017, 7(3), 284; https://doi.org/10.3390/app7030284 - 14 Mar 2017

Viewed by 4765

Abstract

Using classic differential quadrature formulae and uniform grids, this paper systematically constructs a variety of high-order finite difference schemes, and some of these schemes are consistent with the so-called boundary value methods. The derived difference schemes enjoy the same stability and accuracy properties [...] Read more.

Using classic differential quadrature formulae and uniform grids, this paper systematically constructs a variety of high-order finite difference schemes, and some of these schemes are consistent with the so-called boundary value methods. The derived difference schemes enjoy the same stability and accuracy properties with correspondent differential quadrature methods but have a simpler form of calculation; thus, they can be seen as a compact format of classic differential quadrature methods. Through systematic Fourier stability analysis, the characteristics such as the dissipation, dispersion and resolution of the different schemes were studied and compared. Full article

(This article belongs to the Special Issue Applications of Generalized Differential and Integral Quadrature Methods)

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15 pages, 4798 KiB

Open AccessArticle

Physics of Prestall Propagating Disturbances in Axial Compressors and Their Potential as a Stall Warning Indicator

by Mario Eck^1,*, Silvio Geist^1,2,* and Dieter Peitsch^1,*

¹ Institute of Aeronautics and Astronautics, Technische Universität Berlin, Marchstr. 12-14, Berlin D-10587, Germany

² Present address: Laboratory of Turbomachinery, Helmut Schmidt Universität, Holstenhofweg 85, Hamburg D-22043, Germany

Appl. Sci. 2017, 7(3), 285; https://doi.org/10.3390/app7030285 - 14 Mar 2017

Cited by 42 | Viewed by 7755

Abstract

Axial compressors in aero engines are prone to suffering a breakdown of orderly flow when operating at the peak of the pressure rise characteristic. The damaging potential of separated flows is why a safe distance has to be left between every possible operating [...] Read more.

Axial compressors in aero engines are prone to suffering a breakdown of orderly flow when operating at the peak of the pressure rise characteristic. The damaging potential of separated flows is why a safe distance has to be left between every possible operating point and an operating point at which stall occurs. During earlier investigations of stall inception mechanisms, a new type of prestall instability has been found. In this study, it could be demonstrated that the prestall instability characterised by discrete flow disturbances can be clearly assigned to the subject of “Rotating Instabilities”. Propagating disturbances are responsible for the rise in blade passing irregularity. If the mass flow is reduced successively, the level of irregularity increases until the prestall condition devolves into rotating stall. The primary objective of the current work is to highlight the basic physics behind these prestall disturbances by complementary experimental and numerical investigations. Before reaching the peak of the pressure rise characteristic flow, disturbances appear as small vortex tubes with one end attached to the casing and the other attached to the suction surface of the rotor blade. These vortex structures arise when the entire tip region is affected by blockage and at the same time the critical rotor incidence is not exceeded in this flow regime. Furthermore, a new stall indicator was developed by applying statistical methods to the unsteady pressure signal measured over the rotor blade tips, thus granting a better control of the safety margin. Full article

(This article belongs to the Special Issue Gas Turbines Propulsion and Power)

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21 pages, 1005 KiB

Open AccessReview

A Review of Flywheel Energy Storage System Technologies and Their Applications

by Mustafa E. Amiryar^*

and Keith R. Pullen^*

School of Mathematics, Computer Science and Engineering, University of London, London EC1V 0HB, UK

Appl. Sci. 2017, 7(3), 286; https://doi.org/10.3390/app7030286 - 16 Mar 2017

Cited by 435 | Viewed by 55558

Abstract

Energy storage systems (ESS) provide a means for improving the efficiency of electrical systems when there are imbalances between supply and demand. Additionally, they are a key element for improving the stability and quality of electrical networks. They add flexibility into the electrical [...] Read more.

Energy storage systems (ESS) provide a means for improving the efficiency of electrical systems when there are imbalances between supply and demand. Additionally, they are a key element for improving the stability and quality of electrical networks. They add flexibility into the electrical system by mitigating the supply intermittency, recently made worse by an increased penetration of renewable generation. One energy storage technology now arousing great interest is the flywheel energy storage systems (FESS), since this technology can offer many advantages as an energy storage solution over the alternatives. Flywheels have attributes of a high cycle life, long operational life, high round-trip efficiency, high power density, low environmental impact, and can store megajoule (MJ) levels of energy with no upper limit when configured in banks. This paper presents a critical review of FESS in regards to its main components and applications, an approach not captured in earlier reviews. Additionally, earlier reviews do not include the most recent literature in this fast-moving field. A description of the flywheel structure and its main components is provided, and different types of electric machines, power electronics converter topologies, and bearing systems for use in flywheel storage systems are discussed. The main applications of FESS are explained and commercially available flywheel prototypes for each application are described. The paper concludes with recommendations for future research. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

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9 pages, 1998 KiB

Open AccessArticle

Optical Coherence Tomography (OCT) for Time-Resolved Imaging of Alveolar Dynamics in Mechanically Ventilated Rats

by Christian Schnabel^1,*, Maria Gaertner^1,2 and Edmund Koch¹

¹ Department of Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring, Faculty of Medicine CGC, Technische Universität Dresden, Dresden 01307, Germany

² InfraTec GmbH, Gostritzer Straße 61-63, Dresden 01217, Germany

Appl. Sci. 2017, 7(3), 287; https://doi.org/10.3390/app7030287 - 15 Mar 2017

Cited by 4 | Viewed by 5535

Abstract

Though artificial ventilation is an essential life-saving treatment, the mechanical behavior of lung tissue at the alveolar level is still unknown. Therefore, we need to understand the tissue response during artificial ventilation at this microscale in order to develop new and more protective [...] Read more.

Though artificial ventilation is an essential life-saving treatment, the mechanical behavior of lung tissue at the alveolar level is still unknown. Therefore, we need to understand the tissue response during artificial ventilation at this microscale in order to develop new and more protective ventilation methods. Optical coherence tomography (OCT) combined with intravital microscopy (IVM) is a promising tool for visualizing lung tissue dynamics with a high spatial and temporal resolution in uninterruptedly ventilated rats. We present a measurement setup using a custom-made animal ventilator and a gating technique for data acquisition of time-resolved sequences. Full article

(This article belongs to the Special Issue Development and Application of Optical Coherence Tomography (OCT))

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20 pages, 10684 KiB

Open AccessReview

Enhancement of High-Intensity Focused Ultrasound Heating by Short-Pulse Generated Cavitation

by Shin Yoshizawa^1,*, Ryo Takagi¹ and Shin-ichiro Umemura²

¹ Department of Communications Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan

² Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579, Japan

Appl. Sci. 2017, 7(3), 288; https://doi.org/10.3390/app7030288 - 16 Mar 2017

Cited by 28 | Viewed by 10664

Abstract

A target tissue can be thermally coagulated in high-intensity focused ultrasound (HIFU) treatment noninvasively. HIFU thermal treatments have been clinically applied to various solid tumors. One of the problems in HIFU treatments is a long treatment time. Acoustically driven microbubbles can accelerate the [...] Read more.

A target tissue can be thermally coagulated in high-intensity focused ultrasound (HIFU) treatment noninvasively. HIFU thermal treatments have been clinically applied to various solid tumors. One of the problems in HIFU treatments is a long treatment time. Acoustically driven microbubbles can accelerate the ultrasonic heating, resulting in the significant reduction of the treatment time. In this paper, a method named “trigger HIFU exposure” which employs cavitation microbubbles is introduced and its results are reviewed. A trigger HIFU sequence consists of high-intensity short pulses followed by moderate-intensity long bursts. Cavitation bubbles induced in a multiple focal regions by rapidly scanning the focus of high-intensity pulses enhanced the temperature increase significantly and produced a large coagulation region with high efficiency. Full article

(This article belongs to the Special Issue Biomedical Ultrasound)

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18 pages, 801 KiB

Open AccessArticle

An Explicit Approach Toward Modeling Thermo-Coupled Deformation Behaviors of SMPs

by Hao Li, Xie-Fei Ding, Zheng-Nan Yin and Heng Xiao^*

Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Yanchang Road 149, Shanghai 200072, China

Appl. Sci. 2017, 7(3), 289; https://doi.org/10.3390/app7030289 - 16 Mar 2017

Cited by 1 | Viewed by 3927

Abstract

A new elastoplastic

J_{2}

-flow models with thermal effects is proposed toward simulating thermo-coupled finite deformation behaviors of shape memory polymers. In this new model, an elastic potential evolving with development of plastic flow is incorporated to characterize the stress-softening effect at [...] Read more.

A new elastoplastic

J_{2}

-flow models with thermal effects is proposed toward simulating thermo-coupled finite deformation behaviors of shape memory polymers. In this new model, an elastic potential evolving with development of plastic flow is incorporated to characterize the stress-softening effect at unloading and, moreover, thermo-induced plastic flow is introduced to represent the strain recovery effect at heating. It is shown that any given test data for both effects may be accurately simulated by means of direct and explicit procedures. Numerical examples for model predictions compare well with test data in literature. Full article

(This article belongs to the Section Materials Science and Engineering)

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18 pages, 3832 KiB

Open AccessFeature PaperArticle

Ultrasonic Techniques for Air Void Size Distribution and Property Evaluation in Both Early-Age and Hardened Concrete Samples

by Shuaicheng Guo¹, Qingli Dai^1,*, Xiao Sun¹, Ye Sun²

and Zhen Liu¹

¹ Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, MI 49931-1295, USA

² Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA

Appl. Sci. 2017, 7(3), 290; https://doi.org/10.3390/app7030290 - 16 Mar 2017

Cited by 24 | Viewed by 6983

Abstract

Entrained air voids can improve the freeze-thaw durability of concrete, and also affect its mechanical and transport properties. Therefore, it is important to measure the air void structure and understand its influence on concrete performance for quality control. This paper aims to measure [...] Read more.

Entrained air voids can improve the freeze-thaw durability of concrete, and also affect its mechanical and transport properties. Therefore, it is important to measure the air void structure and understand its influence on concrete performance for quality control. This paper aims to measure air void structure evolution at both early-age and hardened stages with the ultrasonic technique, and evaluates its influence on concrete properties. Three samples with different air entrainment agent content were specially prepared. The air void structure was determined with optimized inverse analysis by achieving the minimum error between experimental and theoretical attenuation. The early-age sample measurement showed that the air void content with the whole size range slightly decreases with curing time. The air void size distribution of hardened samples (at Day 28) was compared with American Society for Testing and Materials (ASTM) C457 test results. The air void size distribution with different amount of air entrainment agent was also favorably compared. In addition, the transport property, compressive strength, and dynamic modulus of concrete samples were also evaluated. The concrete transport decreased with the curing age, which is in accordance with the air void shrinkage. The correlation between the early-age strength development and hardened dynamic modulus with the ultrasonic parameters was also evaluated. The existence of clustered air voids in the Interfacial Transition Zone (ITZ) area was found to cause severe compressive strength loss. The results indicated that this developed ultrasonic technique has potential in air void size distribution measurement, and demonstrated the influence of air void structure evolution on concrete properties during both early-age and hardened stages. Full article

(This article belongs to the Special Issue Advanced Asphalt Materials and Paving Technologies)

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8 pages, 1256 KiB

Open AccessArticle

Surface Improvement of Halloysite Nanotubes

by Tayser Sumer Gaaz^1,2,*, Abu Bakar Sulong^1,*, Abdul Amir H. Kadhum³, Mohamed H. Nassir⁴ and Ahmed A. Al-Amiery⁵

¹ Department of Mechanical & Materials Engineering, Faculty of Engineering & Built Environment, University Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia

² Department of Machinery Equipment Engineering Techniques, Technical College Al-Musaib, Al-Furat Al-Awsat Technical University, Al-Musaib, Babil 51009, Iraq

³ Department of Chemical & Process Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia

⁴ Program of Chemical Engineering, Taylor’s University-Lakeside Campus, Subang Jaya 47500, Selangor, Malaysia

⁵ Environmental Research Center, University of Technology (UOT), Baghdad 10001, Iraq

Appl. Sci. 2017, 7(3), 291; https://doi.org/10.3390/app7030291 - 16 Mar 2017

Cited by 25 | Viewed by 6182

Abstract

A novel development on halloysite-polyvinyl alcohol (HNTs-PVA) nanocomposites has been conducted using malonic acid (MA) by crosslinking PVA and HNTs. PVA-MA crosslinking produces smooth surfaces, which play an important role in enhancing the properties of HNTs-PVA nanocomposite. The crystallographic structures of crosslinked HNTs-PVA [...] Read more.

A novel development on halloysite-polyvinyl alcohol (HNTs-PVA) nanocomposites has been conducted using malonic acid (MA) by crosslinking PVA and HNTs. PVA-MA crosslinking produces smooth surfaces, which play an important role in enhancing the properties of HNTs-PVA nanocomposite. The crystallographic structures of crosslinked HNTs-PVA show almost no change as depicted by the X-ray diffraction (XRD)-2θ-peak, suggesting that MA has no or little influence on the crystallographic structure of the HNTs-PVA. Images taken by field emission scanning electron microscope (FESEM) suggest possible effects of MA on the morphology and internal features of HNTs-PVA by reducing the agglomeration of HNTs, which is considered a decisive step in improving the surface qualities of HNTs. Investigating the samples using the Brunauer–Emmelt–Teller (BET) technique showed that the surface area was increased by about 10 times, reaching the second highest recorded results compared to the HNTs, which could be considered a breakthrough step in enhancing the properties of HNTs-PVA due to MA crosslinking. Full article

(This article belongs to the Special Issue Surface Modification of Halloysite Nanotubes)

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14 pages, 2390 KiB

Open AccessArticle

Birch Bark Dry Extract by Supercritical Fluid Technology: Extract Characterisation and Use for Stabilisation of Semisolid Systems

by Markus Armbruster¹, Mathias Mönckedieck², Regina Scherließ²

, Rolf Daniels¹ and Martin A. Wahl^1,*

¹ Department of Pharmaceutical Technology, Auf der Morgenstelle 8, 72076 Tübingen, Germany

² Department of Pharmaceutics and Biopharmaceutics, Grasweg 9a, 24118 Kiel, Germany

Appl. Sci. 2017, 7(3), 292; https://doi.org/10.3390/app7030292 - 16 Mar 2017

Cited by 12 | Viewed by 8844

Abstract

Triterpene compounds like betulin, betulinic acid, erythrodiol, oleanolic acid and lupeol are known for many pharmacological effects. All these substances are found in the outer bark of birch. Apart from its pharmacological effects, birch bark extract can be used to stabilise semisolid systems. [...] Read more.

Triterpene compounds like betulin, betulinic acid, erythrodiol, oleanolic acid and lupeol are known for many pharmacological effects. All these substances are found in the outer bark of birch. Apart from its pharmacological effects, birch bark extract can be used to stabilise semisolid systems. Normally, birch bark extract is produced for this purpose by extraction with organic solvents. Employing supercritical fluid technology, our aim was to develop a birch bark dry extract suitable for stabilisation of lipophilic gels with improved properties while avoiding the use of toxic solvents. With supercritical carbon dioxide, three different particle formation methods from supercritical solutions have been tested. First, particle deposition was performed from a supercritical solution in an expansion chamber. Second, the Rapid Expansion of Supercritical Solutions (RESS) method was used for particle generation. Third, a modified RESS-procedure, forming the particles directly into the thereby gelated liquid, was developed. All three methods gave yields from 1% to 5.8%, depending on the techniques employed. The triterpene composition of the three extracts was comparable: all three gave more stable oleogels compared to the use of an extract obtained by organic solvent extraction. Characterizing the rheological behaviour of these gels, a faster gelling effect was seen together with a lower concentration of the extract required for the gel formation with the supercritical fluid (SCF)-extracts. This confirms the superiority of the supercritical fluid produced extracts with regard to the oleogel forming properties. Full article

(This article belongs to the Special Issue The Applications of Supercritical Carbon Dioxide)

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15 pages, 1176 KiB

Open AccessReview

A Review of the Application of Zeolite Materials in Warm Mix Asphalt Technologies

by Agnieszka Woszuk^1,* and Wojciech Franus²

¹ Department of Roads and Bridges, Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland

² Department Geotechnical Engineering, Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland

Appl. Sci. 2017, 7(3), 293; https://doi.org/10.3390/app7030293 - 16 Mar 2017

Cited by 86 | Viewed by 7210

Abstract

Among warm mix asphalt (WMA) technologies, asphalt foaming techniques offer high potential in terms of decreasing production temperature. Reluctance of manufacturers to introduce this technology is connected with the concerns of a large investment costs. However, there are known additives which, through asphalt [...] Read more.

Among warm mix asphalt (WMA) technologies, asphalt foaming techniques offer high potential in terms of decreasing production temperature. Reluctance of manufacturers to introduce this technology is connected with the concerns of a large investment costs. However, there are known additives which, through asphalt foaming, allow a decrease in temperatures by approximately 30 °C; the use of these additives do not involve expensive investment in order to change the asphalt mix production method. These additives are zeolites, that is, minerals of the aluminosilicate group, the crystalline structure of which contains water bound in a specific way. Its release, at mix asphalt production temperatures, causes asphalt foaming. It is currently known that zeolites can be used in WMA, including natural and synthetic zeolites obtained using chemical reagents and waste. This review presents the results of studies of WMA technology, including the effects of zeolite addition on asphalt properties and mix asphalt, as well as related environmental, economic, and technological benefits. Full article

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14 pages, 375 KiB

Open AccessArticle

Two- and Three-Photon Partial Photoionization Cross Sections of Li⁺, Ne⁸⁺ and Ar¹⁶⁺ under XUV Radiation

by William Hanks, John T. Costello and Lampros A. A. Nikolopoulos^*

School of Physical Sciences, Dublin City University, Dublin 9, Ireland

Appl. Sci. 2017, 7(3), 294; https://doi.org/10.3390/app7030294 - 17 Mar 2017

Cited by 3 | Viewed by 6300

Abstract

In this work, we present the photon energy dependence of the two- and three-photon cross sections of the two-electron Li⁺, Ne⁸⁺ and Ar¹⁶⁺ ions, following photoionization from their ground state. The expressions for the cross sections are based on [...] Read more.

In this work, we present the photon energy dependence of the two- and three-photon cross sections of the two-electron Li⁺, Ne⁸⁺ and Ar¹⁶⁺ ions, following photoionization from their ground state. The expressions for the cross sections are based on the lowest-order (non-vanishing) perturbation theory for the electric field, while the calculations are made with the use of an ab initio configuration interaction method. The ionization cross section is dominated by pronounced single photon resonances in addition to peaks associated with doubly excited resonances. In the case of two-photon ionization, and in the non-resonant part of the cross section, we find that the ¹D ionization channel overwhelms the ¹S one. We also observe that, as one moves from the lowest atomic number ion, namely Li⁺, to the highest atomic number ion, namely Ar¹⁶⁺, the cross sections generally decrease. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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16 pages, 11424 KiB

Open AccessArticle

Selected Issues of the Indicating Measurements in a Spark Ignition Engine with an Additional Expansion Process

by Marcin Noga

Institute of Automobiles and Internal Combustion Engines, Division of Mechatronics, Cracow University of Technology, Al. Jana Pawla II 37, 31-864 Kraków, Poland

Appl. Sci. 2017, 7(3), 295; https://doi.org/10.3390/app7030295 - 17 Mar 2017

Cited by 12 | Viewed by 7099

Abstract

The paper presents the results of research on the turbocharged spark ignition engine with additional exhaust expansion in a separate cylinder, which is commonly known as the five-stroke engine. The research engine has been constructed based on the four cylinder engine in which [...] Read more.

The paper presents the results of research on the turbocharged spark ignition engine with additional exhaust expansion in a separate cylinder, which is commonly known as the five-stroke engine. The research engine has been constructed based on the four cylinder engine in which two outer cylinders work as the fired cylinders, while two internally connected inner cylinders constitute the volume of the additional expansion process. The engine represents a powertrain realizing an ultra-expansion cycle. The purpose of the study was to find an effective additional expansion process in the five-stroke engine. Cylinder-pressure indicating measurements were carried out for one of the fired cylinders and the additional expansion cylinder. The study was performed for over 20 different points on the engine operation map. This allowed us to determine a dependence between the pressure indicated in the fired cylinders and in the additional expansion cylinders. A function of the mean pressure indicated in the additional expansion cylinder versus a brake mean effective pressure was also presented. This showed a load threshold from which the work of the cylinders of additional expansion produced benefits for the output of the experimental engine. The issues of mechanical efficiency and effective efficiency of this engine were also discussed. Full article

(This article belongs to the Special Issue Internal Combustion Engines (ICE) for Ground Transport)

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17 pages, 3464 KiB

Open AccessArticle

Gait Planning Research for an Electrically Driven Large-Load-Ratio Six-Legged Robot

by Hong-Chao Zhuang^1,2,*

, Hai-Bo Gao^2,* and Zong-Quan Deng²

¹ College of Mechanical Engineering, Tianjin University of Technology and Education, Tianjin 300222, China

² State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, China

Appl. Sci. 2017, 7(3), 296; https://doi.org/10.3390/app7030296 - 18 Mar 2017

Cited by 18 | Viewed by 5830

Abstract

Gait planning is an important basis for the walking of a legged robot. To improve the walking stability of multi-legged robots and to reduce the impact force between the foot and the ground, gait planning strategies are presented for an electrically driven large-load-ratio [...] Read more.

Gait planning is an important basis for the walking of a legged robot. To improve the walking stability of multi-legged robots and to reduce the impact force between the foot and the ground, gait planning strategies are presented for an electrically driven large-load-ratio six-legged robot. First, the configuration and walking gait of the electrically driven large-load-ratio six-legged robot are designed. The higher-stable swing sequences of legs and typical walking modes are respectively obtained. Based on the Denavit–Hartenberg (D–H) method, the analyses of the forward and inverse kinematics are implemented. The mathematical models of the articulated rotation angles are respectively established. In view of the buffer device installed at the end of shin to decrease the impact force between the foot and the ground, an initial lift height of the leg is brought into gait planning when the support phase changes into the transfer phase. The mathematical models of foot trajectories are established. Finally, a prototype of the electrically driven large-load-ratio six-legged robot is developed. The experiments of the prototype are carried out regarding the aspects of the walking speed and surmounting obstacle. Then, the reasonableness of gait planning is verified based on the experimental results. The proposed strategies of gait planning lay the foundation for effectively reducing the foot–ground impact force and can provide a reference for other large-load-ratio multi-legged robots. Full article

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12 pages, 2055 KiB

Open AccessArticle

Effect of Fibers on Mixture Design of Stone Matrix Asphalt

by Yanping Sheng^1,*, Haibin Li², Ping Guo³, Guijuan Zhao², Huaxin Chen¹ and Rui Xiong¹

¹ School of Materials Science and Engineering, Chang’an University, Xi’an 710064, China

² School of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an 710054, China

³ Xi’an Highway Research Institute, Xi’an 710054, Shaanxi, China

Appl. Sci. 2017, 7(3), 297; https://doi.org/10.3390/app7030297 - 18 Mar 2017

Cited by 33 | Viewed by 7312

Abstract

Lignin fibers typically influence the mixture performance of stone matrix asphalt (SMA), such as strength, stability, durability, noise level, rutting resistance, fatigue life, and water sensitivity. However, limited studies were conducted to analyze the influence of fibers on the percent voids in mineral [...] Read more.

Lignin fibers typically influence the mixture performance of stone matrix asphalt (SMA), such as strength, stability, durability, noise level, rutting resistance, fatigue life, and water sensitivity. However, limited studies were conducted to analyze the influence of fibers on the percent voids in mineral aggregate in bituminous mixture (VMA) during the mixture design. This study analyzed the effect of different fibers and fiber contents on the VMA in SMA mixture design. A surface-dry condition method test and Marshall Stability test were applied on the SMA mixture with four different fibers (i.e., flocculent lignin fiber, mineral fiber, polyester fiber, blended fiber). The test results indicated that the bulk specific gravity of SMA mixtures and asphalt saturation decreased with the increasing fiber content, whilst the percent air voids in bituminous mixtures (VV), Marshall Stability and VMA increased. Mineral fiber had the most obvious impact on the bulk specific gravity of bituminous mixtures, while flocculent lignin fiber had a minimal impact. The mixture with mineral fiber and polyester fiber had significant effects on the volumetric properties, and, consequently, exhibited better VMA over the conventional SMA mixture with lignin fiber. Modified fiber content range was also provided, which will widen the utilization of mineral fiber and polyester fiber in the applications of SMA mixtures. The mixture evaluation suggested no statistically significant difference between lignin fiber and polyester fiber on the stability. The mineral fiber required a much larger fiber content to improve the mixture performance than other fibers. Overall, the results can be a reference to guide SMA mixture design. Full article

(This article belongs to the Special Issue Advanced Asphalt Materials and Paving Technologies)

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12 pages, 2670 KiB

Open AccessArticle

Modeling and Finite Element Analysis of Load-Carrying Performance of a Wind Turbine Considering the Influence of Assembly Factors

by Jianmei Wang^1,*, Ke Ning¹, Liang Tang¹, Reza Malekian²

, Yinan Liang¹ and Zhixiong Li^3,4,*

¹ School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China

² Department of Electrical, Electronic & Computer Engineering, University of Pretoria, Pretoria 0002, South Africa

³ School of Mechatronic Engineering, China University of Mining Technology, Xuzhou 221116, China

⁴ School of Manufacturing & Mechanical Engineering, UNSW, Sydney 2200, Australia

Appl. Sci. 2017, 7(3), 298; https://doi.org/10.3390/app7030298 - 18 Mar 2017

Cited by 9 | Viewed by 4997

Abstract

In this work, a wind turbine shrink disk is used as the research object to investigate load-carrying performance of a multi-layer interference fit, and the theoretical model and finite element model are constructed. According to those models, a MW-level turbine shrink disk is [...] Read more.

In this work, a wind turbine shrink disk is used as the research object to investigate load-carrying performance of a multi-layer interference fit, and the theoretical model and finite element model are constructed. According to those models, a MW-level turbine shrink disk is designed, and a test device is developed to apply torque to this turbine shrink disk by hydraulic jack. Then, the circumferential slip between the contact surfaces is monitored and the slip of all contact surfaces is zero. This conclusion verifies the reasonability of the proposed models. The effect of the key influencing factors, such as machining deviation, assembly clearance and propel stroke, were analyzed. The contact pressure and load torque of the mating surfaces were obtained by building typical models with different parameters using finite element analysis (FEA). The results show that the minimum assembly clearance and the machining deviation within the machining range have little influence on load-carrying performance of multi-layer interference fit, while having a greater influence on the maximum assembly clearance and the propel stroke. The results also show that the load-carrying performance of a multiple-layer interference fit can be ensured only if the key factors are set within a reasonable design range. To avoid the abnormal operation of equipment caused by insufficient load torque, the propel stroke during practical assembly should be at least 0.95 times the designed propel stroke, which is significant in guiding the design and assembly of the multi-layer interference fit. Full article

(This article belongs to the Section Energy Science and Technology)

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13 pages, 3102 KiB

Open AccessArticle

Quality Monitoring for Laser Welding Based on High-Speed Photography and Support Vector Machine

by Teng Wang^1,*, Juequan Chen¹, Xiangdong Gao² and Wei Li³

¹ School of Computer Science, South China Normal University, Guangzhou 510631, China

² School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510090, China

³ School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631, China

Appl. Sci. 2017, 7(3), 299; https://doi.org/10.3390/app7030299 - 20 Mar 2017

Cited by 18 | Viewed by 5882

Abstract

In order to improve the prediction ability of welding quality during high-power disk laser welding, a new approach was proposed and applied in the classification of the dynamic features of metal vapor plume. Six features were extracted through the color image processing method. [...] Read more.

In order to improve the prediction ability of welding quality during high-power disk laser welding, a new approach was proposed and applied in the classification of the dynamic features of metal vapor plume. Six features were extracted through the color image processing method. Three features, including the area of plume, number of spatters, and horizontal coordinate of plume centroid, were selected based on the classification accuracy rates and Pearson product-moment correlation coefficients. A support vector machine model was adopted to classify the welding quality status into two categories, good or poor. The results demonstrated that the support vector machine model established according to the selected features had satisfactory prediction and generalization ability. The classification accuracy rate was higher than 90%, and the model could be applied in the prediction of welding quality during high-power disk laser welding. Full article

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13 pages, 2824 KiB

Open AccessArticle

Experimental Study of Imbibition Characteristics of Silica Sol in Coal-Measure Mudstone Matrix

by Dongjiang Pan¹

, Nong Zhang^1,*, Changliang Han¹, Sen Yang^1,2

, Chenghao Zhang¹ and Zhengzheng Xie¹

¹ Key Laboratory of Deep Coal Resource Mining, Ministry of Education of China, China University of Mining and Technology, Xuzhou 221116, China

² Department of Energy and Mineral Engineering, G3 Center and Energy Institute, Pennsylvania State University, University Park, PA 16802, USA

Appl. Sci. 2017, 7(3), 300; https://doi.org/10.3390/app7030300 - 20 Mar 2017

Cited by 12 | Viewed by 5097

Abstract

Coal-measure mudstone is a typical dual-porosity media, and grouting in a matrix system is dominantly controlled by the imbibition effect for silica sol. This paper studies the imbibition effect using mudstone in the Huaibei mining area and silica sol as grouting material as [...] Read more.

Coal-measure mudstone is a typical dual-porosity media, and grouting in a matrix system is dominantly controlled by the imbibition effect for silica sol. This paper studies the imbibition effect using mudstone in the Huaibei mining area and silica sol as grouting material as an example. Groutability, driving force, and diffusion difficulty affecting the imbibition effect were tested by a mercury porosimeter, nanoparticle size analyzer, optical contact-angle measuring device, surface tension meter, and rotary viscosity meter. After finely grinding a mudstone sample, a pressureless imbibition process was conducted through nuclear magnetic resonance equipment for 216 h to study colloid spontaneous migration and phase characteristics. Results show that silica sol absorption rate follows a power function and that the spectrograms of T₂ are distributed in a triple peak pattern, with a tendency to move to the right of vertex time. The paper lays a theoretical and experimental foundation for field grouting in the coal mine. Full article

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11 pages, 2844 KiB

Open AccessFeature PaperArticle

Exergy Analysis of Air-Gap Membrane Distillation Systems for Water Purification Applications

by Daniel Woldemariam^1,2,*

, Andrew Martin¹ and Massimo Santarelli^1,2

¹ Energy Technology Department, KTH Royal Institute of Technology, Brinellvägen 68, SE-100 44 Stockholm, Sweden

² Department of Energy (DENERG), Politecnico di Torino, PoliTo, Corso Duca degli Abruzzi 24, 10129 Turin, Italy

Appl. Sci. 2017, 7(3), 301; https://doi.org/10.3390/app7030301 - 20 Mar 2017

Cited by 21 | Viewed by 6199

Abstract

Exergy analyses are essential tools for the performance evaluation of water desalination and other separation systems, including those featuring membrane distillation (MD). One of the challenges in the commercialization of MD technologies is its substantial heat demand, especially for large scale applications. Identifying [...] Read more.

Exergy analyses are essential tools for the performance evaluation of water desalination and other separation systems, including those featuring membrane distillation (MD). One of the challenges in the commercialization of MD technologies is its substantial heat demand, especially for large scale applications. Identifying such heat flows in the system plays a crucial role in pinpointing the heat loss and thermal integration potential by the help of exergy analysis. This study presents an exergetic evaluation of air-gap membrane distillation (AGMD) systems at a laboratory and pilot scale. A series of experiments were conducted to obtain thermodynamic data for the water streams included in the calculations. Exergy efficiency and destruction for two different types of flat-plate AGMD were analyzed for a range of feed and coolant temperatures. The bench scale AGMD system incorporating condensation plate with more favorable heat conductivity contributed to improved performance parameters including permeate flux, specific heat demand, and exergy efficiency. For both types of AGMD systems, the contributions of the major components involved in exergy destruction were identified. The result suggested that the MD modules caused the highest fraction of destructions followed by re-concentrating tanks. Full article

(This article belongs to the Special Issue Membrane Distillation)

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29 pages, 1193 KiB

Open AccessArticle

Question-Driven Methodology for Analyzing Emergency Room Processes Using Process Mining

by Eric Rojas^1,*

, Marcos Sepúlveda¹

, Jorge Munoz-Gama¹

, Daniel Capurro^2,3, Vicente Traver^4,5

and Carlos Fernandez-Llatas^4,5

¹ Computer Science Department, School of Engineering, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile

² Internal Medicine Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile

³ Department of Biomedical Informatics and Medical Education, School of Medicine, University of Washington, Seattle, WA 98109, USA

⁴ Instituto Universitario de las Tecnologías de la Información y de las Comunicaciones (ITACA), Universitat Politécnica de València, Valencia 46022, Spain

⁵ Unidad Mixta de Reingeniería de Procesos Sociosanitarios (eRPSS), Instituto de Investigación Sanitaria del Hospital Universitario y Politecnico La Fe, Bulevar Sur S/N, Valencia 46026, Spain

Appl. Sci. 2017, 7(3), 302; https://doi.org/10.3390/app7030302 - 21 Mar 2017

Cited by 59 | Viewed by 10602

Abstract

In order to improve the efficiency and effectiveness of Emergency Rooms (ER), it is important to provide answers to frequently-posed questions regarding all relevant processes executed therein. Process mining provides different techniques and tools that help to obtain insights into the analyzed processes [...] Read more.

In order to improve the efficiency and effectiveness of Emergency Rooms (ER), it is important to provide answers to frequently-posed questions regarding all relevant processes executed therein. Process mining provides different techniques and tools that help to obtain insights into the analyzed processes and help to answer these questions. However, ER experts require certain guidelines in order to carry out process mining effectively. This article proposes a number of solutions, including a classification of the frequently-posed questions about ER processes, a data reference model to guide the extraction of data from the information systems that support these processes and a question-driven methodology specific for ER. The applicability of the latter is illustrated by means of a case study of an ER service in Chile, in which ER experts were able to obtain a better understanding of how they were dealing with episodes related to specific pathologies, triage severity and patient discharge destinations. Full article

(This article belongs to the Special Issue Smart Healthcare)

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12 pages, 826 KiB

Open AccessArticle

Measurement of Heat Flow Transmitted through a Stacked-Screen Regenerator of Thermoacoustic Engine

by Shu Han Hsu^* and Tetsushi Biwa

Department of Mechanical Systems and Design, Tohoku University, Sendai 980-8579, Japan

Appl. Sci. 2017, 7(3), 303; https://doi.org/10.3390/app7030303 - 20 Mar 2017

Cited by 6 | Viewed by 7141

Abstract

A stacked-screen regenerator is a key component in a thermoacoustic Stirling engine. Therefore, the choice of suitable mesh screens is important in the engine design. To verify the applicability of four empirical equations used in the field of thermoacoustic engines and Stirling engines, [...] Read more.

A stacked-screen regenerator is a key component in a thermoacoustic Stirling engine. Therefore, the choice of suitable mesh screens is important in the engine design. To verify the applicability of four empirical equations used in the field of thermoacoustic engines and Stirling engines, this report describes the measurements of heat flow rates transmitted through the stacked screen regenerator inserted in an experimental setup filled with pressurized Argon gas having mean pressure of 0.45 MPa. Results show that the empirical equations reproduce the measured heat flow rates to a mutually similar degree, although their derivation processes differ. Additionally, results suggest that two effective pore radii would be necessary to account for the viscous and thermal behaviors of the gas oscillating in the stacked-screen regenerators. Full article

(This article belongs to the Special Issue Heat Transfer Processes in Oscillatory Flow Conditions)

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16 pages, 5272 KiB

Open AccessArticle

Low Temperature Performance Characteristics of Reclaimed Asphalt Pavement (RAP) Mortars with Virgin and Aged Soft Binders

by Feipeng Xiao^1,*, Ruoyu Li¹, Henglong Zhang² and Serji Amirkhanian^3,*

¹ Key Laboratory of Road and Traffic Engineering of Ministry of Education, Tongji University, Shanghai 201804, China

² School of Civil Engineering, Hunan University, Changsha 410082, China

³ State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China

Appl. Sci. 2017, 7(3), 304; https://doi.org/10.3390/app7030304 - 20 Mar 2017

Cited by 20 | Viewed by 5929

Abstract

Reclaimed asphalt pavement (RAP) has many advantages and is utilized to improve the high temperature properties of asphalt mixtures. Low temperature cracking is a predominant distress in asphalt pavements containing RAP materials. Thus, the evaluation of fracture resistance for asphalt mixtures containing RAP [...] Read more.

Reclaimed asphalt pavement (RAP) has many advantages and is utilized to improve the high temperature properties of asphalt mixtures. Low temperature cracking is a predominant distress in asphalt pavements containing RAP materials. Thus, the evaluation of fracture resistance for asphalt mixtures containing RAP is of interest. The objective of this research is to explore the low temperature performance characteristics of RAP mortars containing sieved RAP and soft binders at three aged states. The stiffness values and m-values from bending beam rheometer (BBR) tests at three test temperatures of −18 °C, −12 °C and −6 °C were obtained to conduct the minimum low temperature grades. RAP mortar with a higher aged binder content had a higher minimum low temperature regardless of RAP source. In addition, RAP mortars with virgin soft binder had the best low temperature resistance followed by the RAP mortars with rolling thin film oven (RTFO) and pressure-aged vessel (PAV) binders. Full article

(This article belongs to the Special Issue Advanced Asphalt Materials and Paving Technologies)

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17 pages, 2031 KiB

Open AccessArticle

Fatigue Life Prediction of High Modulus Asphalt Concrete Based on the Local Stress-Strain Method

by Mulian Zheng^1,*, Peng Li^1,*, Jiangang Yang², Hongyin Li³, Yangyang Qiu⁴ and Zhengliang Zhang⁵

¹ Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, South Erhuan Middle Section, Xi’an 710064, Shaanxi, China

² Civil Engineering Materials Laboratory, East China Jiaotong University, Shuang Gang East Street, Nanchang 330000, Jiangxi, China

³ Shandong Highway Administration Bureau, Shungeng Road of Jinan City, Jinan 250000, Shandong, China

⁴ Jinhua Traffic Planning and Design Institute, Songlian Road of Jin Dong District, Jinhua 321015, Zhejiang, China

⁵ Anhui Highway Administration Center, Da Bie Shan Road of Hefei City, Hefei 230088, Anhui, China

Appl. Sci. 2017, 7(3), 305; https://doi.org/10.3390/app7030305 - 20 Mar 2017

Cited by 20 | Viewed by 7461

Abstract

Previously published studies have proposed fatigue life prediction models for dense graded asphalt pavement based on flexural fatigue test. This study focused on the fatigue life prediction of High Modulus Asphalt Concrete (HMAC) pavement using the local strain-stress method and direct tension fatigue [...] Read more.

Previously published studies have proposed fatigue life prediction models for dense graded asphalt pavement based on flexural fatigue test. This study focused on the fatigue life prediction of High Modulus Asphalt Concrete (HMAC) pavement using the local strain-stress method and direct tension fatigue test. First, the direct tension fatigue test at various strain levels was conducted on HMAC prism samples cut from plate specimens. Afterwards, their true stress-strain loop curves were obtained and modified to develop the strain-fatigue life equation. Then the nominal strain of HMAC course determined using finite element method was converted into local strain using the Neuber method. Finally, based on the established fatigue equation and converted local strain, a method to predict the pavement fatigue crack initiation life was proposed and the fatigue life of a typical HMAC overlay pavement which runs a risk of bottom-up cracking was predicted and validated. Results show that the proposed method was able to produce satisfactory crack initiation life. Full article

(This article belongs to the Special Issue Advanced Asphalt Materials and Paving Technologies)

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15 pages, 3286 KiB

Open AccessArticle

Influence of Hard Segments on the Thermal, Phase-Separated Morphology, Mechanical, and Biological Properties of Polycarbonate Urethanes

by Rong Zhu^1,2, Xinyu Wang^1,2,*, Jing Yang³, Yiyu Wang^1,2, Zongrui Zhang^1,2, Yuanjing Hou^1,2, Fei Lin^1,2 and Yi Li⁴

¹ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China

² Biomedical Materials and Engineering Research Center of Hubei Province, Wuhan University of Technology, Wuhan 430070, China

³ School of Foreign Languages, Wuhan University of Technology, Wuhan 430070, China

⁴ Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China

Appl. Sci. 2017, 7(3), 306; https://doi.org/10.3390/app7030306 - 20 Mar 2017

Cited by 29 | Viewed by 8477

Abstract

Abstract: In this study, we have fabricated a series of polycarbonate polyurethanes using a two-step bulk reaction by the melting pre-polymer solution-casting method in order to synthesize biomedical polyurethane elastomers with good mechanical behavior and biostability. The polyurethanes were prepared using dibutyltin dilaurate [...] Read more.

Abstract: In this study, we have fabricated a series of polycarbonate polyurethanes using a two-step bulk reaction by the melting pre-polymer solution-casting method in order to synthesize biomedical polyurethane elastomers with good mechanical behavior and biostability. The polyurethanes were prepared using dibutyltin dilaurate as the catalyst, poly(1,6-hexanediol)carbonate microdiols (PCDL) as the soft segment, and the chain extender 1,4-butanediol (BDO) and aliphatic 1,6-hexamethylene diisocyanate (HDI) as the hard segments. The chemical structures and physical properties of the obtained films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimeter (DSC), and mechanical property tests. The surface properties and degrees of microphase separation were further analyzed by water droplet contact angle measurements (CA) and atomic force microscopy (AFM). The materials exhibited a moderate toxic effect on the tetrazolium (MTT) assay and good hemocompatibility through hemolytic tests, indicating a good biocompatibility of the fabricated membranes. The materials could be considered as potential and beneficial suitable materials for tissue engineering, especially in the fields of artificial blood-contacting implants or other biomedical applications. Full article

(This article belongs to the Special Issue Biomaterials and Scaffolds in Tissue Engineering Applications and Cancer Therapies)

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8 pages, 1843 KiB

Open AccessCommunication

Universal Voltage Conveyor and its Novel Dual-Output Fully-Cascadable VM APF Application

by Norbert Herencsar^*

, Jaroslav Koton and Pavel Hanak

Department of Telecommunications, Brno University of Technology, Technicka 3082/12,616 00 Brno, Czech Republic

Appl. Sci. 2017, 7(3), 307; https://doi.org/10.3390/app7030307 - 20 Mar 2017

Cited by 17 | Viewed by 4250

Abstract

This letter presents a novel realization of a voltage-mode (VM) first-order all-pass filter (APF) with attractive features. The proposed circuit employs a single readily available six-terminal active device called as universal voltage conveyor (UVC) and only grounded passive components, which predict its easy [...] Read more.

This letter presents a novel realization of a voltage-mode (VM) first-order all-pass filter (APF) with attractive features. The proposed circuit employs a single readily available six-terminal active device called as universal voltage conveyor (UVC) and only grounded passive components, which predict its easy monolithic integration with desired circuit simplicity. The auxiliary voltage input (W) and output (ZP, ZN) terminals of the device fully ensure easy cascadability of VM APF, since the input and output terminal impedances are theoretically infinitely high and zero, respectively. Moreover, thanks to mutually inverse outputs of the UVC, the proposed filter simultaneously provides both inverting and non-inverting outputs from the same configuration. All of these features make the UVC a unique active device currently available in the literature. The behavior of the filter was experimentally measured using the readily available UVC-N1C 0520 chip, which was produced in cooperation with ON Semiconductor Czech Republic, Ltd. Full article

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22 pages, 7836 KiB

Open AccessArticle

Use of the Genetic Algorithm-Based Fuzzy Logic Controller for Load-Frequency Control in a Two Area Interconnected Power System

by Ertugrul Cam¹, Goksu Gorel^2,*

and Hayati Mamur³

¹ Department of Electrical and Electronics Engineering, Kirikkale University, Kirikkale 71450, Turkey

² Department of Electrical and Energy, Cankiri Karatekin University, Cankiri 18100, Turkey

³ Department of Electrical and Electronics Engineering, Manisa Celal Bayar University, Manisa 45140, Turkey

Appl. Sci. 2017, 7(3), 308; https://doi.org/10.3390/app7030308 - 22 Mar 2017

Cited by 48 | Viewed by 10131

Abstract

The use of renewable energy resources has created some problems for power systems. One of the most important of these is load frequency control (LFC). In this study, in order to solve the LFC problem, modern control methods were applied to a two [...] Read more.

The use of renewable energy resources has created some problems for power systems. One of the most important of these is load frequency control (LFC). In this study, in order to solve the LFC problem, modern control methods were applied to a two area multi source interconnected power system. A photovoltaic solar power plant (PV-SPP) was also connected, in order to identify the harmful effects on the frequency of the system. A new Genetic-based Fuzzy Logic (GA-FL) controller was designed to control the frequency of the system. For comparison, conventional proportional-integral-derivative (PID), fuzzy logic (FL), and Genetic Algorithm (GA)-PID controllers were also designed. The new control method exhibited a better performance than the conventional and other modern control methods, because of the low overshoot and short settling time. All simulations were realized with the Matlab-Simulink program. Full article

(This article belongs to the Special Issue Distribution Power Systems)

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20 pages, 9864 KiB

Open AccessArticle

Experimental Identification and Vibration Control of A Piezoelectric Flexible Manipulator Using Optimal Multi-Poles Placement Control

by Junqiang Lou¹

, Jiangjiang Liao¹, Yanding Wei^2,*, Yiling Yang²

and Guoping Li¹

¹ College of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211, China

² China Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China

Appl. Sci. 2017, 7(3), 309; https://doi.org/10.3390/app7030309 - 21 Mar 2017

Cited by 15 | Viewed by 6131

Abstract

This paper presents experimental identification and vibration suppression of a flexible manipulator with piezoelectric actuators and strain sensors using optimal multi-poles placement control. To precisely identify the system model, a reduced order transfer function with relocated zeros is proposed, and a first-order inertia [...] Read more.

This paper presents experimental identification and vibration suppression of a flexible manipulator with piezoelectric actuators and strain sensors using optimal multi-poles placement control. To precisely identify the system model, a reduced order transfer function with relocated zeros is proposed, and a first-order inertia element is added to the model. Comparisons show the identified model match closely with the experimental results both in the time and frequency domains, and a fit of 97.2% is achieved. Based on the identified model, a full-state multi-poles placement controller is designed, and the optimal locations of the closed loop poles are determined where the move distance of the closed loop poles is the shortest. The feasibility of the proposed controller is validated by simulations. Moreover, the controller is tested for different locations of the closed loop poles, and an excellent performance of the optimal locations of the closed loop poles is shown. Finally, the effectiveness of the proposed controller is demonstrated by experiments. Results show that the vibrations of the expected modes are significantly diminished. Accordingly, multi-mode vibrations of the manipulator are well attenuated. Full article

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Appl. Sci., Volume 7, Issue 3 (March 2017) – 101 articles

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