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Appl. Sci., Volume 10, Issue 11 (June-1 2020) – 391 articles

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Cover Story (view full-size image) Traditional fault injection systems utilized an artificial trigger close to a target operation. [...] Read more.
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Open AccessArticle
Deep Learning-Based Wrapped Phase Denoising Method for Application in Digital Holographic Speckle Pattern Interferometry
Appl. Sci. 2020, 10(11), 4044; https://doi.org/10.3390/app10114044 - 12 Jun 2020
Viewed by 292
Abstract
This paper presents a new processing method for denoising interferograms obtained by digital holographic speckle pattern interferometry (DHSPI) to serve in the structural diagnosis of artworks. DHSPI is a non-destructive and non-contact imaging method that has been successfully applied to the structural diagnosis [...] Read more.
This paper presents a new processing method for denoising interferograms obtained by digital holographic speckle pattern interferometry (DHSPI) to serve in the structural diagnosis of artworks. DHSPI is a non-destructive and non-contact imaging method that has been successfully applied to the structural diagnosis of artworks by detecting hidden subsurface defects and quantifying the deformation directly from the surface illuminated by coherent light. The spatial information of structural defects is mostly delivered as local distortions interrupting the smooth distribution of intensity during the phase-shifted formation of fringe patterns. Distortions in fringe patterns are recorded and observed from the estimated wrapped phase map, but the inevitable electronic speckle noise directly affects the quality of the image and consequently the assessment of defects. An effective method for denoising DHSPI wrapped phase based on deep learning is presented in this paper. Although a related method applied to interferometry for reducing Gaussian noise has been introduced, it is not suitable for application in DHSPI to reduce speckle noise. Thus, the paper proposes a new method to remove speckle noise in the wrapped phase. Simulated data and experimental captured data from samples prove that the proposed method can effectively reduce the speckle noise of the DHSPI wrapped phase to extract the desired information. The proposed method is helpful for accurately detecting defects in complex defect topography maps and may help to accelerate defect detection and characterization procedures. Full article
(This article belongs to the Special Issue Intelligent Processing on Image and Optical Information, Volume II)
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Open AccessArticle
Numerical Analysis of the Influence of Empty Channels Design on Performance of Resin Flow in a Porous Plate
Appl. Sci. 2020, 10(11), 4054; https://doi.org/10.3390/app10114054 - 11 Jun 2020
Viewed by 361
Abstract
This numerical study aims to investigate the influence of I and T-shaped empty channels’ geometry on the filling time of resin in a rectangular porous enclosed mold, mimicking the main operating principle of a liquid resin infusion (LRI) process. Geometrical optimization was conducted [...] Read more.
This numerical study aims to investigate the influence of I and T-shaped empty channels’ geometry on the filling time of resin in a rectangular porous enclosed mold, mimicking the main operating principle of a liquid resin infusion (LRI) process. Geometrical optimization was conducted with the constructal design (CD) and exhaustive search (ES) methods. The problem was subjected to two constraints (areas of porous mold and empty channels). In addition, the I and T-shaped channels were subjected to one and three degrees of freedom (DOF), respectively. Conservation equations of mass and momentum for modeling of resin/air mixture flow were numerically solved with the finite volume method (FVM). Interaction between the phases was considered with the volume of fluid method (VOF), and the effect of porous medium resistance in the resin flow was calculated with Darcy’s law. For the studied conditions, the best T-shaped configuration resulted in a filling time nearly three times lower than that for optimal I-shaped geometry, showing that the complexity of the channels benefited the performance. Moreover, the best T-shaped configurations were achieved for long single and bifurcated branches, except for configurations with skinny channels, which saw the generation of permanent voids. Full article
(This article belongs to the Special Issue Composite Materials in Design Processes)
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Open AccessArticle
RRM Prediction of Erythrocyte Band3 Protein as Alternative Receptor for SARS-CoV-2 Virus
Appl. Sci. 2020, 10(11), 4053; https://doi.org/10.3390/app10114053 - 11 Jun 2020
Viewed by 373
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new coronavirus causing a worldwide pandemic. It is infecting respiratory organs and, in more severe cases, the lungs, where it is infecting the human cells through the angiotensin-converting enzyme 2 (ACE2) receptor. In severe [...] Read more.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new coronavirus causing a worldwide pandemic. It is infecting respiratory organs and, in more severe cases, the lungs, where it is infecting the human cells through the angiotensin-converting enzyme 2 (ACE2) receptor. In severe cases, it is characterized not only by difficulties in breathing through infected lungs, but also with disproportionally and, thus far, unexplained low levels of oxygen in the blood. Here, we propose that, besides the infection of respiratory organs through ACE2 receptors, there is an additional infection in the red blood cells (erythrocytes). There could be a possible for SARS-CoV-2 to pass through the alveoli membrane in the lungs and infect the red blood cells through another receptor. Using our own biophysical model, the Resonant Recognition Model, we propose that the red blood cell (RBC) Band3 protein on the surface of red blood cells is a possible entry point for the SARS-CoV-2 virus into red blood cells. Full article
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Open AccessArticle
Biostimulant Effect of Marine Macroalgae Bioextract on Pepper Grown in Greenhouse
Appl. Sci. 2020, 10(11), 4052; https://doi.org/10.3390/app10114052 - 11 Jun 2020
Viewed by 434
Abstract
Marine macroalgae are a vast source of raw materials and biologically active molecules used in the pharmaceutical, cosmetic, food and agricultural industries. The search for a food free of chemical residues by consumers has led producers to use environmentally friendly and economically viable [...] Read more.
Marine macroalgae are a vast source of raw materials and biologically active molecules used in the pharmaceutical, cosmetic, food and agricultural industries. The search for a food free of chemical residues by consumers has led producers to use environmentally friendly and economically viable products as they are a source of natural compounds, forming a new and promising area of study. In this context, concentrated marine algae extracts (CMAEs) are an important alternative in this production model. This work aimed to evaluate the effects of CMAEs as biostimulants in plant metabolism, promotion of growth, development and production of pepper (Capsicum annuum L.) cultivated in a greenhouse. This work was carried out from 24 June to 30 October 2019. The number of leaves, plant length, fresh and dry plant mass, root length, root fresh and dry mass, fruit production and the metabolic performance were evaluated. The results of the stomatal conductance of pepper plants, production and biofortification were related with the levels of nutrients absorbed by the plant, which reflected the effect of the applied biostimulant. The dose that showed the most promising results was the 0.5% concentration of CMAEs. Full article
(This article belongs to the Special Issue Algae as a Nutritional and Bioactive Biomass)
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Open AccessArticle
Overlap Avoidance of Mobility Models for Multi-UAVs Reconnaissance
Appl. Sci. 2020, 10(11), 4051; https://doi.org/10.3390/app10114051 - 11 Jun 2020
Viewed by 297
Abstract
As avionics technologies have advanced, it is possible to perform many aerial applications which demand cooperative work with multiple Unmanned Aerial Vehicles (UAVs). Since one of the basic applications is reconnaissance, we focus on efficient cooperative reconnaissance. While random mobility models are useful [...] Read more.
As avionics technologies have advanced, it is possible to perform many aerial applications which demand cooperative work with multiple Unmanned Aerial Vehicles (UAVs). Since one of the basic applications is reconnaissance, we focus on efficient cooperative reconnaissance. While random mobility models are useful for multi-UAVs reconnaissance, they suffer from overlapped reconnaissance problem that two or more UAVs reconnoiter a region at the same time. The overlapped reconnaissance also leads to imbalanced reconnaissance in which an area scanned by one UAV may be re-visited soon by the other UAV. Thus, we provide overlap avoidance schemes for the existing reconnaissance mobility models and enhance their performance. Throughout the simulations, we evaluate the effect of applying overlap avoidance in the existing models. The simulation results show that overlapped area is reduced by up to 20 times and 90%-coverage reaching time is improved by up to 19%. Full article
(This article belongs to the Section Aerospace Science and Engineering)
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Open AccessArticle
Elimination of Gear Clearance for the Rotary Table of Ultra Heavy Duty Vertical Milling Lathe Based on Dual Servo Motor Driving System
Appl. Sci. 2020, 10(11), 4050; https://doi.org/10.3390/app10114050 - 11 Jun 2020
Viewed by 253
Abstract
The effective way to improve the position accuracy of rotary table of ultra-heavy vertical milling lathe is to reduce or even eliminate the clearance of mechanical transmission structure. In this paper, a useful method for eliminating the gear clearance of C axis of [...] Read more.
The effective way to improve the position accuracy of rotary table of ultra-heavy vertical milling lathe is to reduce or even eliminate the clearance of mechanical transmission structure. In this paper, a useful method for eliminating the gear clearance of C axis of heavy duty machine tool is proposed based on dual servo motor driving system. The principle of double gear anti-backlash is explained and the process of clearance elimination is determined by adjusting the driving torques of the two motors. The dynamic model of the driving system of the dual servo motor is established, so as to find the non-linearity of the clearance, wear and tooth clearance in the drive system. According to the dynamic model and simulation results, the master-slave control parameters of the dual servo motor system are optimized in order to eliminate the clearance and improve the accuracy of the dual drive C-axis. Experiments are carried out to verify the validity of the proposed anti-backlash method. The experimental result also shows that the indexing accuracy of the table has been improved by more than 50% under different working conditions. Full article
(This article belongs to the Section Mechanical Engineering)
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Open AccessArticle
Examining User Perception of the Size of Multiple Objects in Virtual Reality
Appl. Sci. 2020, 10(11), 4049; https://doi.org/10.3390/app10114049 - 11 Jun 2020
Viewed by 294
Abstract
This article presents a user study into user perception of an object’s size when presented in virtual reality. Critical for users understanding of virtual worlds is their perception of the size of virtual objects. This article is concerned with virtual objects that are [...] Read more.
This article presents a user study into user perception of an object’s size when presented in virtual reality. Critical for users understanding of virtual worlds is their perception of the size of virtual objects. This article is concerned with virtual objects that are within arm’s reach of the user. Examples of such virtual objects could be virtual controls such as buttons, dials and levers that the users manipulate to control the virtual reality application. This article explores the issue of a user’s ability to judge the size of an object relative to a second object of a different colour. The results determined that the points of subjective equality for height and width judgement tasks ranging from 10 to 90 mm were all within an acceptable value. That is to say, participants were able to perceive height and width judgements very close to the target values. The results for height judgement task for just-noticeable difference were all less than 1.5 mm and for the width judgement task less than 2.3 mm. Full article
(This article belongs to the Special Issue Applications of Virtual, Augmented, and Mixed Reality)
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Open AccessArticle
Characterization of Demolition Construction Waste Containing Asbestos, and the Release of Fibrous Dust Particles
Appl. Sci. 2020, 10(11), 4048; https://doi.org/10.3390/app10114048 - 11 Jun 2020
Viewed by 260
Abstract
This paper focuses on the characterization of demolition construction waste containing asbestos fibers and the monitoring of fibrous dust released from asbestos–cement products (ACPs) during their removal from a three-story industrial building. Asbestos-containing products removal was carried out according to a demolition management [...] Read more.
This paper focuses on the characterization of demolition construction waste containing asbestos fibers and the monitoring of fibrous dust released from asbestos–cement products (ACPs) during their removal from a three-story industrial building. Asbestos-containing products removal was carried out according to a demolition management system in terms of protection of workers. The results of a chemical analysis, X-ray diffraction analysis, infrared analysis and scanning electron microscopy of demolition waste samples confirmed the same material quality of asbestos–cement (AC) elements used throughout the building. In addition, a MgO/SiO2 ratio corresponding to a serpentine silicate mineral of chrysotile was detected by means of X-ray fluorescence analysis. Also, crystalline phase calcium silicates and calcium carbonates from the cement matrix were identified in the AC waste. The relatively large differences in the elemental analysis between the sample area and the individual points found by energy-dispersive X-ray spectroscopic mapping are related to the composition heterogeneity. The highest content of magnesium occurs where asbestos fibers predominate in the cement matrix. The measured number concentrations of asbestos fibers before, during, and after asbestos–cement products removal were compared to outdoor concentrations. Indoor concentrations of asbestos fibers during the removal of AC materials did not exceed the permissible limit for a working environment (1000 fibers per one m3), except in three spots out of all the working sites inside the building. A relationship between the number and mass concentrations of asbestos dust is shown. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessReview
Optical Angle Sensor Technology Based on the Optical Frequency Comb Laser
Appl. Sci. 2020, 10(11), 4047; https://doi.org/10.3390/app10114047 - 11 Jun 2020
Viewed by 277
Abstract
A mode-locked femtosecond laser, which is often referred to as the optical frequency comb, has increasing applications in various industrial fields, including production engineering, in the last two decades. Many efforts have been made so far to apply the mode-locked femtosecond laser to [...] Read more.
A mode-locked femtosecond laser, which is often referred to as the optical frequency comb, has increasing applications in various industrial fields, including production engineering, in the last two decades. Many efforts have been made so far to apply the mode-locked femtosecond laser to the absolute distance measurement. In recent years, a mode-locked femtosecond laser has increasing application in angle measurement, where the unique characteristics of the mode-locked femtosecond laser such as the stable optical frequencies, equally-spaced modes in frequency domain, and the ultra-short pulse trains with a high peak power are utilized to achieve precision and stable angle measurement. In this review article, some of the optical angle sensor techniques based on the mode-locked femtosecond laser are introduced. First, the angle scale comb, which can be generated by combining the dispersive characteristic of a scale grating and the discretized modes in a mode-locked femtosecond laser, is introduced. Some of the mode-locked femtosecond laser autocollimators, which have been realized by combining the concept of the angle scale comb with the laser autocollimation, are also explained. Angle measurement techniques based on the absolute distance measurements, lateral chromatic aberration, and second harmonic generation (SHG) are also introduced. Full article
(This article belongs to the Special Issue Manufacturing Metrology)
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Open AccessArticle
Needle Transportable Semi-Automatic Hair Follicle Implanter and Image-Based Hair Density Estimation for Advanced Hair Transplantation Surgery
Appl. Sci. 2020, 10(11), 4046; https://doi.org/10.3390/app10114046 - 11 Jun 2020
Viewed by 289
Abstract
As the number of hair follicles transplanted in a patient is approximately 2000 or more, hair transplantation by a manual implanter requires a considerable amount of time and money and demands a great amount of patience and pain tolerance from both patients and [...] Read more.
As the number of hair follicles transplanted in a patient is approximately 2000 or more, hair transplantation by a manual implanter requires a considerable amount of time and money and demands a great amount of patience and pain tolerance from both patients and surgeons. In addition, many surgeons frequently experience musculoskeletal disorders owing to the numerous simple repetitive motions of the shoulder and wrist during the procedure. Moreover, the results of the surgery may vary depending on the skill of the surgeon. Although the hair follicle extraction technology has advanced in recent years, the hair follicle transplantation technology still uses a simple hand-held implanter owing to the difficulty of transplanting hair follicles and hair. In this study, a needle transportable semi-automatic hair follicle implanter that can continuously transplant hair follicles is introduced to alleviate the inconvenience of the existing manual implanter. In the developed semi-automatic implanter, a plurality of needles, into which the hair follicles are inserted, are sequentially supplied from the needle supply magazine to the implanter body by the guide groove. The hair follicles in the supplied needles are transplanted to the scalp through the forward and backward movement of the needle gripper and driving motors. The developed implanter can transplant several hair follicles without any replacement, which can shorten surgery time and reduce the fatigue experienced by patients and surgeons. The effectiveness of the proposed implanter was verified through the results of animal and clinical experiments. Full article
(This article belongs to the Special Issue Implantable Medical Device)
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Open AccessArticle
Investigations of the Energy Transfer in the Phycobilisome Antenna of Arthrospira platensis Using Femtosecond Spectroscopy
Appl. Sci. 2020, 10(11), 4045; https://doi.org/10.3390/app10114045 - 11 Jun 2020
Viewed by 264
Abstract
Understanding the energy transfer in phycobilisomes extracted from cyanobacteria can be used for building biomimetic hybrid systems for optimized solar energy collection and photocurrent amplification. In this paper, we applied time-resolved absorption and fluorescence spectroscopy to investigate the ultrafast dynamics in a hemidiscoidal [...] Read more.
Understanding the energy transfer in phycobilisomes extracted from cyanobacteria can be used for building biomimetic hybrid systems for optimized solar energy collection and photocurrent amplification. In this paper, we applied time-resolved absorption and fluorescence spectroscopy to investigate the ultrafast dynamics in a hemidiscoidal phycobilisome obtained from Arthrospira platensis. We obtained the steady-state and time-resolved optical properties and identified the possible pathways of the excitation energy transfer in the phycobilisome and its components, phycocyanin and allophycocyanin. The transient absorption data were studied using global analysis and revealed the existence of ultrafast kinetics down to 850 fs in the phycobilisome. The fluorescence lifetimes in the nanosecond time-scale assigned to the final emitters in each sample were obtained from the time-correlated single photon counting fluorescence experiments. Full article
(This article belongs to the Special Issue Ultrashort Pulses: Generation and Applications)
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Open AccessFeature PaperArticle
Climatology of the Linke and Unsworth–Monteith Turbidity Parameters for Greece: Introduction to the Notion of a Typical Atmospheric Turbidity Year
Appl. Sci. 2020, 10(11), 4043; https://doi.org/10.3390/app10114043 - 11 Jun 2020
Viewed by 289
Abstract
Solar rays are attenuated by the Earth’s atmosphere. This attenuation can be expressed by the turbidity parameters; two of them are the Linke turbidity factor (TL) and the Unsworth–Monteith turbidity coefficient (TUM). In this sudy, both parameters [...] Read more.
Solar rays are attenuated by the Earth’s atmosphere. This attenuation can be expressed by the turbidity parameters; two of them are the Linke turbidity factor (TL) and the Unsworth–Monteith turbidity coefficient (TUM). In this sudy, both parameters are estimated for 33 sites across Greece, and the notion of a Typical Atmospheric Turbidity Year (TATY) is also introduced. Use of the modified clearness index (kt) is made, while a suggestion for a modified diffuse fraction (kd) is given. The adoption of the four climatic zones in Greece for energy purposes is made, where the variation of TL and TUM is studied during a TATY under all and clear-sky conditions. The analysis shows maximum levels in both parameters in late winter–early spring in morning and evening hours, with minimum values at midday. The intra-annual variation of the parameters shows maximum values around March and August and minimum values in summertime and late winter. Maps of annual mean TL and TUM values over Greece show persistent minimum values over Peloponnese and maximum values over South Ionian Sea. Linear expressions of TUM vs. TL are derived for all sites under all and clear-sky conditions. Finally, linear expressions for kd vs. kt are given for all sites and sky conditions. Full article
(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)
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Open AccessArticle
Adaptive Sensor Array Error Calibration Based Impact Localization on Composite Structure
Appl. Sci. 2020, 10(11), 4042; https://doi.org/10.3390/app10114042 - 11 Jun 2020
Viewed by 278
Abstract
Gains and phases delay induced by sensor position error would significantly degrade the performance of high-resolution two-dimensional multiple signal classification (2D-MUSIC) algorithm, which resulting in low positioning estimation accuracy and poor imaging. In this study, adaptive piezoelectric sensor array calibration based method is [...] Read more.
Gains and phases delay induced by sensor position error would significantly degrade the performance of high-resolution two-dimensional multiple signal classification (2D-MUSIC) algorithm, which resulting in low positioning estimation accuracy and poor imaging. In this study, adaptive piezoelectric sensor array calibration based method is proposed for impact localization on composite structure. First, observed signal vector from the sensor array is represented by error calibration matrix with unknown gains and phases, and then it used to construct the cost function including sensor array parameters. Second, a 2D-MUSIC algorithm based on linear attenuation calibration is applied for estimating the initial estimate of impact location. Finally, substituting the initial estimate, the cost function is minimized by adaptive iterative to calculate the sensor array error parameters and the exact location of the impact source. Both finite element method (FEM) simulation and experimental results on carbon-fiber composite panel demonstrate the validity and effectiveness of the proposed method. Full article
(This article belongs to the Special Issue Structural Health Monitoring & Nondestructive Testing 2020)
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Open AccessArticle
Investigation of Roller-Tape Contact Pair Used in Precision Mechatronic System
Appl. Sci. 2020, 10(11), 4041; https://doi.org/10.3390/app10114041 - 11 Jun 2020
Viewed by 245
Abstract
Smoothness of tape movement and stability of the tape area where elements are generated are very important in precision mechatronic devices where precise elements are generated on a steel tape, controlling them in real time. During movement, deformations and vibrations form in the [...] Read more.
Smoothness of tape movement and stability of the tape area where elements are generated are very important in precision mechatronic devices where precise elements are generated on a steel tape, controlling them in real time. During movement, deformations and vibrations form in the steel tape area where elements are generated as a result of imperfections of movement equipment, contact between the roller surface and the tape, and errors arising in the movement process. This article is based on the need for a detailed theoretical and experimental research of the effects occurring during the movement of the precision steel tape used in measuring systems with precision elements generated on the tape, including an investigation of the roller-tape contact. The article also aims to develop a model of the system for measuring the displacement of the tape in a raster formation device, to investigate and assess possible effects of external and internal factors on steel tape parameters. The article presents experimental research conducted for determining dynamic variables forming during the movement of a steel tape, assessing the factors that may cause raster generation errors in dynamic mode. Full article
(This article belongs to the Special Issue Systems Engineering: Availability and Reliability)
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Open AccessArticle
Quantum Dilation and Erosion
Appl. Sci. 2020, 10(11), 4040; https://doi.org/10.3390/app10114040 - 11 Jun 2020
Viewed by 246
Abstract
The dilation and erosion operations are the first fundamental step in classical image processing. They are important in many image processing algorithms to extract basic image features, such as geometric shapes; such shapes are then fed to higher level algorithms for object identification [...] Read more.
The dilation and erosion operations are the first fundamental step in classical image processing. They are important in many image processing algorithms to extract basic image features, such as geometric shapes; such shapes are then fed to higher level algorithms for object identification and recognition. In this paper, we present an improved quantum method to realize dilation and erosion in imaging processing. Unlike in the classical way, in the quantum version of imaging processing, all of the information is stored in quantum bits (qubits). We use qubits to code the location and other information of each pixel of the images and apply quantum operators (or quantum gates) to accomplish specific functions. Because of quantum entanglement and other nonintuitive features in quantum mechanics, qubits have many advantages over classical bits, but their nature presents challenges in designing quantum algorithms. We first built the quantum circuit theoretically, and then ran it on the IBM Quantum Experience platform to test and process real images. With this algorithm, we are looking forward to more potential applications in quantum computation. Full article
(This article belongs to the Section Quantum Science and Technology)
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Open AccessFeature PaperArticle
Use of Response Surface Methodology to Investigate the Effects of Sodium Chloride Substitution with Potassium Chloride on Dough’s Rheological Properties
Appl. Sci. 2020, 10(11), 4039; https://doi.org/10.3390/app10114039 - 11 Jun 2020
Viewed by 272
Abstract
Bakery products are one of the main sources of dietary sodium intake of the world’s population. During the last decade, sodium intake has increased worldwide and nowadays the World Health Organization recommends reducing sodium intake by up to 2 g Na/day. KCl is [...] Read more.
Bakery products are one of the main sources of dietary sodium intake of the world’s population. During the last decade, sodium intake has increased worldwide and nowadays the World Health Organization recommends reducing sodium intake by up to 2 g Na/day. KCl is the leading substitute for reducing sodium in bakery products. Therefore, the main purpose of our study was to investigate the impact of sodium reduction on dough’s rheological properties by reformulating the dough recipe using two types of salts, namely NaCl and KCl, with different amounts added to wheat flour. In order to establish their combination for obtaining the optimum rheological properties of dough, the response surface methodology (RSM) by the Design Expert software was used. The effect of combined NaCl and KCl salts were made on mixing, viscometric and fermentation process by using Farinograph, Extensograph, Amylograph and Rheofermentometer devices. On dough’s rheological properties, KCl and NaCl presented a significant effect (p < 0.01) on water absorption, stability, energy, dough resistance to extension, falling number and all Rheofermentometer-analyzed values. Mathematical models were achieved between independent variables, the KCl and NaCl amounts, and the dependent ones, dough rheological values. The optimal values obtained through RSM for the KCl and NaCl salts were of 0.37 g KCl/100 g and 1.31 g NaCl/100 g wheat flour, which leads to a 22% replacement of NaCl in the dough recipe. Full article
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Open AccessArticle
Electro-Thermal and Aging Lithium-Ion Cell Modelling with Application to Optimal Battery Charging
Appl. Sci. 2020, 10(11), 4038; https://doi.org/10.3390/app10114038 - 11 Jun 2020
Viewed by 276
Abstract
This paper deals with optimal charging versus aging minimization for lithium-ion batteries. The optimal charging strategy proposed involves charging controllers whose design relies on a battery model. The model, especially designed for automotive battery management systems applications, is recalled in this paper. It [...] Read more.
This paper deals with optimal charging versus aging minimization for lithium-ion batteries. The optimal charging strategy proposed involves charging controllers whose design relies on a battery model. The model, especially designed for automotive battery management systems applications, is recalled in this paper. It provides the voltage response of a cell to an input current. It also models side reactions that produce degradation mechanisms and thus decrease battery performance. Side reaction modelling involves taking into account the temperature cell variations, which are thus also modelled. The association of the three above-mentioned sub-models leads to an electro-thermal battery aging model used to design an optimal charging strategy that simultaneously takes into account the minimization of charging time and maximization of battery lifetime. Thus, to achieve a charging controller that manages battery health, an appropriate charging trajectory was computed by solving an optimization problem minimizing aging. Then, a charge control loop was designed. The nonlinear behavior of the battery was taken into account through the linearization of the electro-thermal aging model in different operating conditions. To take into account the resulting linear model family, the CRONE design methodology was used. The principles of this methodology are recapped and the design of the charging control loop is explained. The efficiency of the resulting charge controller is illustrated by several simulations. Full article
(This article belongs to the Special Issue Control and Automation)
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Open AccessArticle
Verification of Optimized Real-time Hybrid Control System for Prediction of Nonlinear Materials Behavior with 3-DOF Dynamic Test
Appl. Sci. 2020, 10(11), 4037; https://doi.org/10.3390/app10114037 - 11 Jun 2020
Viewed by 255
Abstract
Real-time hybrid method is an economical and efficient test method to evaluate the dynamic behavior. The purpose of this study is to develop the computational algorithm and to prove the reliability of a real-time hybrid control system. For performing the multi-direction dynamic test, [...] Read more.
Real-time hybrid method is an economical and efficient test method to evaluate the dynamic behavior. The purpose of this study is to develop the computational algorithm and to prove the reliability of a real-time hybrid control system. For performing the multi-direction dynamic test, three dynamic actuators and the optimized real-time hybrid system with new hybrid simulation program (FEAPH) and a simplified inter-communication were optimized. To verify the reliability and applicability of the real-time hybrid control system, 3-DOF (3 Degrees of Freedom) non-linear dynamic tests with physical model were conducted on a steel and concrete frame structure. As a ground acceleration, El Centro and Northridge earthquake waves were applied. As a result, the maximum error of numerical analysis is 13% compared with the result of shaking table test. However, the result of real-time hybrid test shows good agreement with the shaking table test. The real-time hybrid test using FEAPH can make good progress on the total testing time and errors. Therefore, this test method using FEAPH can be effectively and cheaply used to evaluate the dynamic performance of the full-scale structure, instead of shaking table and full-scale test. Full article
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Open AccessArticle
Salespeople Performance Evaluation with Predictive Analytics in B2B
Appl. Sci. 2020, 10(11), 4036; https://doi.org/10.3390/app10114036 - 11 Jun 2020
Viewed by 271
Abstract
Performance Evaluation is a process that occurs multiple times per year on a company. During this process, the manager and the salesperson evaluate how the salesperson performed on numerous Key Performance Indicators (KPIs). To prepare the evaluation meeting, managers have to gather data [...] Read more.
Performance Evaluation is a process that occurs multiple times per year on a company. During this process, the manager and the salesperson evaluate how the salesperson performed on numerous Key Performance Indicators (KPIs). To prepare the evaluation meeting, managers have to gather data from Customer Relationship Management System, Financial Systems, Excel files, among others, leading to a very time-consuming process. The result of the Performance Evaluation is a classification followed by actions to improve the performance where it is needed. Nowadays, through predictive analytics technologies, it is possible to make classifications based on data. In this work, the authors applied a Naive Bayes model over a dataset that is composed by sales from 594 salespeople along 3 years from a global freight forwarding company, to classify salespeople into pre-defined categories provided by the business. The classification is done in 3 classes, being: Not Performing, Good, and Outstanding. The classification was achieved based on KPI’s like growth volume and percentage, sales variability along the year, opportunities created, customer base line, target achievement among others. The authors assessed the performance of the model with a confusion matrix and other techniques like True Positives, True Negatives, and F1 score. The results showed an accuracy of 92.50% for the whole model. Full article
(This article belongs to the Special Issue Applied Machine Learning)
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Open AccessArticle
Automated Chlorine Dosage in a Simulated Drinking Water Treatment Plant: A Real Case Study
Appl. Sci. 2020, 10(11), 4035; https://doi.org/10.3390/app10114035 - 11 Jun 2020
Viewed by 312
Abstract
In this paper, we present a simulator of a drinking water treatment plant. The model of the plant was based in hydraulic and matter transportation models. In order to not introduce more inaccuracies in the simulation, the control system was based in the [...] Read more.
In this paper, we present a simulator of a drinking water treatment plant. The model of the plant was based in hydraulic and matter transportation models. In order to not introduce more inaccuracies in the simulation, the control system was based in the real equipment deployed in the plant. This fact was the challenging part of the simulator, and an accurate design is presented in this research, wherein the sampling time had to be limited to interchange data between the SCADA in the plant and the simulator in real time. Due to the impossibility to stop the plant when testing the new control strategy, a simulator implemented the plant behavior under different extreme conditions. The validation of the simulator was performed with real data obtained from the plant. Full article
(This article belongs to the Special Issue Sustainable Environmental Solutions)
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Open AccessArticle
Pilot-Aided Frame Synchronization in Optical OFDM Systems
Appl. Sci. 2020, 10(11), 4034; https://doi.org/10.3390/app10114034 - 11 Jun 2020
Viewed by 304
Abstract
Efficient frame synchronization is essential for data recovery in communication systems. In this study, a single pilot sequence is used to achieve both frame synchronization and peak-to-average power ratio (PAPR) reduction. The two systems considered are direct-current biased optical orthogonal frequency division multiplexing [...] Read more.
Efficient frame synchronization is essential for data recovery in communication systems. In this study, a single pilot sequence is used to achieve both frame synchronization and peak-to-average power ratio (PAPR) reduction. The two systems considered are direct-current biased optical orthogonal frequency division multiplexing (DCO-OFDM) and asymmetrically clipped O-OFDM (ACO-OFDM). The pilot symbol is allocated to odd indexed subcarriers only. Thus, the synchronization algorithm leverages the mirror symmetric property of the pilot symbol within a frame to detect the start of the pilot signal at the receiver. This scheme has low complexity and gives precise frame synchronization at signal-to-noise ratios as low as 4 dB in an indoor visible light communication (VLC) channel. Full article
(This article belongs to the Special Issue Light Communication: Latest Advances and Prospects)
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Open AccessArticle
Evaluation of Two Extraction Methods for the Analysis of Hydrophilic Low Molecular Weight Compounds from Ganoderma lucidum Spores and Antiproliferative Activity on Human Cell Lines
Appl. Sci. 2020, 10(11), 4033; https://doi.org/10.3390/app10114033 - 11 Jun 2020
Viewed by 262
Abstract
Background: The genus Ganoderma includes about 80 species of mushrooms. Ganoderma lucidum is the best-known fungal species in mycotherapy and likely has the highest number of studies. Numerous bioactive compounds seem to be responsible for its beneficial effects; in particular, triterpenes, peptidoglycans and [...] Read more.
Background: The genus Ganoderma includes about 80 species of mushrooms. Ganoderma lucidum is the best-known fungal species in mycotherapy and likely has the highest number of studies. Numerous bioactive compounds seem to be responsible for its beneficial effects; in particular, triterpenes, peptidoglycans and polysaccharides are the main physiologically active constituents. The aim of the present work is to identify the main bioactive components in aqueous extracts of G. lucidum spores obtained by two different extraction processes. Methods: The spores were at first extracted by a Soxhlet apparatus with n-hexane and the aqueous solutions were submitted to two different procedures: hot water extraction (HWE) and rapid solid-liquid dynamic extraction (RSLDE) using the Naviglio extractor. The extracts were then dialyzed to separate the compounds with higher molecular weight from polar compounds with lower molecular weight. The aqueous extracts and dialyzed fractions were tested on two human cell lines: human colonic epithelial cells (Caco-2) and human colorectal carcinoma cells (HTC-116). Results: GC-MS and NMR data revealed the presence of a mixture of glucose and mannitol in ratio 3.7:1 in the most active fraction. Conclusions: The outside dialysis phase of RSLDE extract seems to be particularly cytotoxic for HTC-116 and, interestingly, solutions with different concentrations of pure mannitol showed cytotoxic activity against this cell line too, although to a lesser extent. Full article
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Open AccessArticle
Magnesium Oxybromides MOB-318 and MOB-518: Brominated Analogues of Magnesium Oxychlorides
Appl. Sci. 2020, 10(11), 4032; https://doi.org/10.3390/app10114032 - 11 Jun 2020
Viewed by 282
Abstract
The search for environmentally sustainable building materials is currently experiencing significant expansion. It is increasingly important to find new materials or reintroduce those that have been set aside to find a good replacement for Portland cement, which is widely used despite being environmentally [...] Read more.
The search for environmentally sustainable building materials is currently experiencing significant expansion. It is increasingly important to find new materials or reintroduce those that have been set aside to find a good replacement for Portland cement, which is widely used despite being environmentally insufficient and energy-intensive. Magnesium oxybromides, analogues to well-known magnesium oxychloride cements, fit both categories of new and reintroduced materials. In this contribution, two magnesium oxybromide phases were prepared and thoroughly analyzed. The stoichiometries of the prepared phases were 5Mg(OH)2∙MgBr2∙8H2O and 3Mg(OH)2∙MgBr2∙8H2O. The phase analysis was determined using X-ray diffraction. The morphology was analyzed with scanning and transmission electron microscopy. The chemical composition was studied using X-ray fluorescence and energy dispersive spectroscopy. Fourier transform infrared spectroscopy was also used. The thermal stability and the mechanism of the release of gasses linked to the heating process, such as water and hydrobromic acid evaporation, were analyzed using simultaneous thermal analysis combined with mass spectroscopy. The obtained results were compared with the data available for magnesium oxychlorides. Full article
(This article belongs to the Special Issue Progressive Cement and Glass-Based Composites and Structures)
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Open AccessArticle
Virtual Reality in Museums: Exploring the Experiences of Museum Professionals
Appl. Sci. 2020, 10(11), 4031; https://doi.org/10.3390/app10114031 - 11 Jun 2020
Viewed by 466
Abstract
The past few years have seen an increase in the use of virtual reality (VR) in museum environments in an attempt for museums to embrace technological innovations and adapt to the challenges of the digital era. While there are studies that examine the [...] Read more.
The past few years have seen an increase in the use of virtual reality (VR) in museum environments in an attempt for museums to embrace technological innovations and adapt to the challenges of the digital era. While there are studies that examine the advantages of VR in museums and visitors’ experiences with it, there are no studies examining the experiences of museum professionals who are responsible for a museum’s objects and narratives. The aim of this paper is to explore the practices, experiences, and perceptions of museum professionals on the use of VR technology in museums, their perceived advantages and challenges of such technologies, and their vision for the future of technology in museums. The paper provides an in-depth analysis of interviews with museum professionals from a number of countries around the world who worked with particular VR projects in their own institutions. The ultimate aim is to offer a more critical and holistic examination and assessment of the use of VR in museums and provide suggestions for designing and developing VR projects in the future. Full article
(This article belongs to the Special Issue Virtual Reality and Its Application in Cultural Heritage)
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Open AccessArticle
Analysis of the Possibility of Using Drill-Type Electrodes for Air Ionization
Appl. Sci. 2020, 10(11), 4030; https://doi.org/10.3390/app10114030 - 11 Jun 2020
Viewed by 278
Abstract
In this article, the authors present the results of the analysis of the ionization efficiency of drill-type needle electrodes in air. The analysis was carried out on the basis of experimental laboratory measurements, examined at alternating voltages. Drill-type electrode systems of different diameters [...] Read more.
In this article, the authors present the results of the analysis of the ionization efficiency of drill-type needle electrodes in air. The analysis was carried out on the basis of experimental laboratory measurements, examined at alternating voltages. Drill-type electrode systems of different diameters were adopted for the tests. The ionization efficiency for this type of electrode has been characterized by values of characteristic voltages, such as the initial voltage of the corona voltage and the sparking voltage. The obtained results were compared with the results of classical conical needle electrodes. The ionization efficiency of drill-type electrodes has been shown to be higher than that of classical conical needle electrodes. Full article
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Open AccessArticle
Reliability Analysis of Layered Soil Slopes Considering Different Spatial Autocorrelation Structures
Appl. Sci. 2020, 10(11), 4029; https://doi.org/10.3390/app10114029 - 11 Jun 2020
Viewed by 335
Abstract
It is widely recognized that different geological formations often vary differently in space. Therefore, soil properties from different layers should be modeled by different autocorrelation functions (ACFs) to reflect such soil heterogeneity. However, the same ACFs are frequently used for different soil layers [...] Read more.
It is widely recognized that different geological formations often vary differently in space. Therefore, soil properties from different layers should be modeled by different autocorrelation functions (ACFs) to reflect such soil heterogeneity. However, the same ACFs are frequently used for different soil layers in slope reliability analysis for simplicity purpose in the literature. The present work is a study on the effects of ACFs on the reliability analysis of layered soil slopes, where the soil properties of different layers are considered by different ACFs. Five commonly used classical ACFs and the non-classical Whittle–Matérn model were investigated in this study. Cholesky decomposition and Monte Carlo simulation were used to simulate the spatial variability of the soil properties and estimate the probability of failure (Pf) of slopes, respectively. Illustrative examples with various parametric studies show that when the soil properties from different layers are characterized by the same ACFs, the Pf of the studied slopes is comparable with that estimated using different ACFs for different soil layers. This indicates that the type of ACF has only a small impact on the slope reliability assessment. However, the Pf may be underestimated by the single exponential ACF and overestimated by the cosine exponential ACF. The scale of fluctuation of the soil properties influences the slope reliability more than the ACFs. In addition, the smoothness parameter in the non-classical model has a significant influence on the reliability of the slope, where Pf increases with the increase of the smoothness parameter. Full article
(This article belongs to the Section Earth Sciences and Geography)
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Open AccessArticle
Development of Classification Algorithms for the Detection of Postures Using Non-Marker-Based Motion Capture Systems
Appl. Sci. 2020, 10(11), 4028; https://doi.org/10.3390/app10114028 - 10 Jun 2020
Viewed by 418
Abstract
The rapid development of algorithms for skeletal postural detection with relatively inexpensive contactless systems and cameras opens up the possibility of monitoring and assessing the health and wellbeing of humans. However, the evaluation and confirmation of posture classifications are still needed. The purpose [...] Read more.
The rapid development of algorithms for skeletal postural detection with relatively inexpensive contactless systems and cameras opens up the possibility of monitoring and assessing the health and wellbeing of humans. However, the evaluation and confirmation of posture classifications are still needed. The purpose of this study was therefore to develop a simple algorithm for the automatic classification of human posture detection. The most affordable solution for this project was through using a Kinect V2, enabling the identification of 25 joints, so as to record movements and postures for data analysis. A total of 10 subjects volunteered for this study. Three algorithms were developed for the classification of different postures in Matlab. These were based on a total error of vector lengths, a total error of angles, multiplication of these two parameters and the simultaneous analysis of the first and second parameters. A base of 13 exercises was then created to test the recognition of postures by the algorithm and analyze subject performance. The best results for posture classification were shown by the second algorithm, with an accuracy of 94.9%. The average degree of correctness of the exercises among the 10 participants was 94.2% (SD1.8%). It was shown that the proposed algorithms provide the same accuracy as that obtained from machine learning-based algorithms and algorithms with neural networks, but have less computational complexity and do not need resources for training. The algorithms developed and evaluated in this study have demonstrated a reasonable level of accuracy, and could potentially form the basis for developing a low-cost system for the remote monitoring of humans. Full article
(This article belongs to the Special Issue Mathematics and Digital Signal Processing)
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Open AccessArticle
Topological Corner Modes in Graphene-Coated Nanowire Waveguide
Appl. Sci. 2020, 10(11), 4027; https://doi.org/10.3390/app10114027 - 10 Jun 2020
Viewed by 316
Abstract
We study the plasmonic second-order topological modes in nanowire waveguides which are covered by monolayer graphene. The waveguide arrays are arranged in the kagome lattice. In a triangle-shaped lattice, the topological modes are localized at the corner of the triangle by tuning the [...] Read more.
We study the plasmonic second-order topological modes in nanowire waveguides which are covered by monolayer graphene. The waveguide arrays are arranged in the kagome lattice. In a triangle-shaped lattice, the topological modes are localized at the corner of the triangle by tuning the spatial spacing between the different waveguides. The corner modes also depend on the corner shape, which only exist at one corner in a rhombic lattice. In addition to the corner modes, both structures also support the topological edge mode. We show that the corner modes experience a smaller modal wavelength, longer propagation distance, and smaller mode volume than the edge modes. The study may be utilized to explore the topological bound modes at the nanoscale. Full article
(This article belongs to the Section Nanotechnology and Applied Nanosciences)
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Open AccessEditorial
Drugs and Vaccines Will Be Necessary to Control Tuberculosis
Appl. Sci. 2020, 10(11), 4026; https://doi.org/10.3390/app10114026 - 10 Jun 2020
Viewed by 294
Abstract
For most infectious diseases, vaccines are used to prevent infection and drugs are used for acute therapy and eradication of established infections [...] Full article
(This article belongs to the Special Issue Tuberculosis Drug Discovery and Development 2019)
Open AccessEditorial
Natural Compounds: A Dynamic Field of Applications
Appl. Sci. 2020, 10(11), 4025; https://doi.org/10.3390/app10114025 - 10 Jun 2020
Viewed by 298
Abstract
Nature represents an amazing source of inspiration since it produces a great diversity of natural compounds selected by evolution, which exhibit multiple biological activities and applications. A large and very active research field is dedicated to identifying biosynthesized compounds, to improve/develop new methodologies [...] Read more.
Nature represents an amazing source of inspiration since it produces a great diversity of natural compounds selected by evolution, which exhibit multiple biological activities and applications. A large and very active research field is dedicated to identifying biosynthesized compounds, to improve/develop new methodologies to produce/reuse natural compounds and to assess their potential for pharmaceutical, cosmetic and food industries, among others, and also to understand their mechanism of action. Here, the main results presented in each work are highlighted. The applications suggested are mostly related to pharmacological uses and involve mainly pure natural compounds and essential oils. These works are significant contributions and reinforce the dynamic field of natural products applications. Full article
(This article belongs to the Special Issue Biological Activity and Applications of Natural Compounds)
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