Latest Articles

Open AccessFeature PaperReview
Protein Adductomics: Analytical Developments and Applications in Human Biomonitoring
Toxics 2019, 7(2), 29; https://doi.org/10.3390/toxics7020029 (registering DOI) -
Abstract
Proteins contain many sites that are subject to modification by electrophiles. Detection and characterisation of these modifications can give insights into environmental agents and endogenous processes that may be contributing factors to chronic human diseases. An untargeted approach, utilising mass spectrometry to detect [...] Read more.
Proteins contain many sites that are subject to modification by electrophiles. Detection and characterisation of these modifications can give insights into environmental agents and endogenous processes that may be contributing factors to chronic human diseases. An untargeted approach, utilising mass spectrometry to detect modified amino acids or peptides, has been applied to blood proteins haemoglobin and albumin, focusing in particular on the N-terminal valine residue of haemoglobin and the cysteine-34 residue in albumin. Technical developments to firstly detect simultaneously multiple adducts at these sites and then subsequently to identify them are reviewed here. Recent studies in which the methods have been applied to biomonitoring human exposure to environmental toxicants are described. With advances in sensitivity, high-throughput handling of samples and robust quality control, these methods have considerable potential for identifying causes of human chronic disease and of identifying individuals at risk. Full article
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Open AccessArticle
Wave Characteristics of Coagulation Bath in Dry-Jet Wet-Spinning Process for Polyacrylonitrile Fiber Production Using Computational Fluid Dynamics
Processes 2019, 7(5), 314; https://doi.org/10.3390/pr7050314 (registering DOI) -
Abstract
In this work, a three-dimensional volume-of-fluid computational fluid dynamics (VOF-CFD) model was developed for a coagulation bath of the dry-jet wet spinning (DJWS) process for the production of polyacrylonitrile (PAN)-based carbon fiber under long-term operating conditions. The PAN-fiber was assumed to be a [...] Read more.
In this work, a three-dimensional volume-of-fluid computational fluid dynamics (VOF-CFD) model was developed for a coagulation bath of the dry-jet wet spinning (DJWS) process for the production of polyacrylonitrile (PAN)-based carbon fiber under long-term operating conditions. The PAN-fiber was assumed to be a deformable porous zone with variations in moving speed, porosity, and permeability. The Froude number, interpreted as the wave-making resistance on the liquid surface, was analyzed according to the PAN-fiber wind-up speed (vPAN). The effect of the PAN speed on the reflection and wake flow formed by drag between a moving object and fluid is presented. A method for tracking the wave amplitude with time is proposed based on the iso-surface of the liquid volume fraction of 0.95. The wave signal for 30 min was divided into the initial and resonance states that were distinguished at 8 min. The maximum wave amplitude was less than 0.5 mm around the PAN-fiber inlet nozzle for vPAN = 0.1–0.5 m/s in the resonance state. The VOF-CFD model is useful in determining the maximum vPAN under an allowable air gap of the DJWS process. Full article
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Open AccessArticle
Improvement of Energy Efficiency and Control Performance of Cooling System Fan Applied to Industry 4.0 Data Center
Electronics 2019, 8(5), 582; https://doi.org/10.3390/electronics8050582 (registering DOI) -
Abstract
This paper proposes a control method to improve the energy efficiency and performance of cooling fans used for cooling. In Industry 4.0, a large number of digital data are used, and a large number of data centers are created to handle these data. [...] Read more.
This paper proposes a control method to improve the energy efficiency and performance of cooling fans used for cooling. In Industry 4.0, a large number of digital data are used, and a large number of data centers are created to handle these data. These data centers consist of information technology (IT) equipment, power systems, and cooling systems. The cooling system is essential to prevent failure and malfunction of the IT equipment, which consumes a considerable amount of energy. This paper proposes a method to reduce the energy used in such cooling systems and to improve the temperature control performance. This paper proposes an fuzzy proportional integral(FPI) controller that controls the input value of the proportional integral(PI) controller by the fuzzy controller according to the operation state, a VFPI (Variable Fuzzy Proportional Integral) controller that adjusts the gain value of the fuzzy controller, and a variable fuzzy proportion integration-variable limit (VFPI-VL) controller that adjusts the limit value of the fuzzy controller’s output value. These controllers control the fan applied to the cooling system and compare the energy consumed and temperature control performance. When the PI controller consumes 100% of the power consumed, the FPI is 50.5%, the VFPI controller is 44.3%, and the VFPI-VL is 32.6%. The power consumption is greatly reduced. In addition, the VFPI-VL controller is the lowest in temperature variation, which improves the energy efficiency and performance of the cooling system using a fan. The methods presented in this paper can not only be applied to fans for cooling, but also to variable speed systems for various purposes and improvement of performance and efficiency can be expected. Full article
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Open AccessArticle
Compact Printable Inverted-M Shaped Chipless RFID Tag Using Dual-Polarized Excitation
Electronics 2019, 8(5), 580; https://doi.org/10.3390/electronics8050580 (registering DOI) -
Abstract
A novel and compact dual-polarized (DP) chipless radio-frequency identification (RFID) tag is presented in this paper. This tag can read both vertical and horizontal orientations within its frequency band, which improves the robustness and detection capability of the RFID system. The proposed tag [...] Read more.
A novel and compact dual-polarized (DP) chipless radio-frequency identification (RFID) tag is presented in this paper. This tag can read both vertical and horizontal orientations within its frequency band, which improves the robustness and detection capability of the RFID system. The proposed tag makes use of the slot length variation encoding technique to improve the encoding capacity. This technique can duplicate the encoding capacity, thereby reducing the overall tag size by almost 50%. In particular, the proposed tag has an encoding capacity of 20 bits in the 3–8 GHz frequency band and achieves data density of around 15.15 bits/cm2. Three prototypes are fabricated and tested outside an anechoic chamber. Furthermore, one tag is tested at different distances (10 cm, 30 cm, and 60 cm) from the reader and the measured results are compared. The simulated and measured results are in reasonable agreement, with acceptable shifts at some frequencies due to fabrication and experimental errors. Full article
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Open AccessArticle
Time Series Analysis to Predict End-to-End Quality of Wireless Community Networks
Electronics 2019, 8(5), 578; https://doi.org/10.3390/electronics8050578 (registering DOI) -
Abstract
Community Networks have been around us for decades being initially deployed in the USA and Europe. They were designed by individuals to provide open and free “do it yourself” Internet access to other individuals in the same community and geographic area. In recent [...] Read more.
Community Networks have been around us for decades being initially deployed in the USA and Europe. They were designed by individuals to provide open and free “do it yourself” Internet access to other individuals in the same community and geographic area. In recent years, they have evolved as a viable solution to provide Internet access in developing countries and rural areas. Their social impact is measurable, as the community is provided with the right and opportunity of communication. Community networks combine wired and wireless links, and the nature of the wireless medium is unreliable. This poses several challenges to the routing protocol. For instance, Link-State routing protocols deal with End-to-End Quality tracking to select paths that maximize the delivery rate and minimize traffic congestion. In this work, we focused on End-to-End Quality prediction by means of time-series analysis to foresee which paths are more likely to change their quality. We show that it is possible to accurately predict End-to-End Quality with a small Mean Absolute Error in the routing layer of large-scale, distributed, and decentralized networks. In particular, we analyzed the path ETX behavior and properties to better identify the best prediction algorithm. We also analyzed the End-to-End Quality prediction accuracy some steps ahead in the future, as well as its dependency on the hour of the day. Besides, we quantified the computational cost of the prediction. Finally, we evaluated the impact of the usage for routing of our approach versus a simplified OLSR (ETX + Dijkstra) on an overloaded network. Full article
Open AccessArticle
Completing Explorer Games with a Deep Reinforcement Learning Framework Based on Behavior Angle Navigation
Electronics 2019, 8(5), 576; https://doi.org/10.3390/electronics8050576 (registering DOI) -
Abstract
In cognitive electronic warfare, when a typical combat vehicle, such as an unmanned combat air vehicle (UCAV), uses radar sensors to explore an unknown space, the target-searching fails due to an inefficient servoing/tracking system. Thus, to solve this problem, we developed an autonomous [...] Read more.
In cognitive electronic warfare, when a typical combat vehicle, such as an unmanned combat air vehicle (UCAV), uses radar sensors to explore an unknown space, the target-searching fails due to an inefficient servoing/tracking system. Thus, to solve this problem, we developed an autonomous reasoning search method that can generate efficient decision-making actions and guide the UCAV as early as possible to the target area. For high-dimensional continuous action space, the UCAV’s maneuvering strategies are subject to certain physical constraints. We first record the path histories of the UCAV as a sample set of supervised experiments and then construct a grid cell network using long short-term memory (LSTM) to generate a new displacement prediction to replace the target location estimation. Finally, we enable a variety of continuous-control-based deep reinforcement learning algorithms to output optimal/sub-optimal decision-making actions. All these tasks are performed in a three-dimensional target-searching simulator, i.e., the Explorer game. Please note that we use the behavior angle (BHA) for the first time as the main factor of the reward-shaping of the deep reinforcement learning framework and successfully make the trained UCAV achieve a 99.96% target destruction rate, i.e., the game win rate, in a 0.1 s operating cycle. Full article
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Open AccessFeature PaperArticle
Microstructure and Mechanical Property Investigation of TaSiN Thin Films Deposited by Reactive Magnetron Sputtering
Coatings 2019, 9(5), 338; https://doi.org/10.3390/coatings9050338 (registering DOI) -
Abstract
Tantalum silicon nitride (Ta–Si–N) films were synthesized on Si substrate via magnetron sputtering. The structure and properties of the Ta–Si–N films were investigated as a function of the N2 content in the N2/Ar gas mixture. Increasing the N2 percentage [...] Read more.
Tantalum silicon nitride (Ta–Si–N) films were synthesized on Si substrate via magnetron sputtering. The structure and properties of the Ta–Si–N films were investigated as a function of the N2 content in the N2/Ar gas mixture. Increasing the N2 percentage in the gas mixture from 7% to 20% changed the film structure from textured hexagonal (hex) Ta2N to nontextured hex Ta2N to a mixture of face-centered cubic (fcc) TaN and hex Ta2N, and finally to fcc TaN. X-ray photoelectron spectroscopy showed Ta–N and Si–N bonds in the films. The film microstructure was found to change from columnar morphology with visible amorphous boundaries (at 13% N2) to columnar morphology with absence of amorphous boundaries (at 15% N2). Increasing N2 content increased hardness in the films with those deposited with 13–15% N2 displaying the highest hardness of ~40 ± 2 GPa. In addition, the 13% N2 films showed a ratio of H/E* > 0.11, elastic recovery of ~60%, low coefficient of friction of 0.6, reduced wear rate (7.09 × 10−6 mm3/N·m), and remained thermally stable up to 800 °C. The results suggest that the Ta–Si–N films have high potential as hard tribological nanocomposite coatings. Full article
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Open AccessFeature PaperArticle
Gas Sensing with Nanoplasmonic Thin Films Composed of Nanoparticles (Au, Ag) Dispersed in a CuO Matrix
Coatings 2019, 9(5), 337; https://doi.org/10.3390/coatings9050337 (registering DOI) -
Abstract
Magnetron sputtered nanocomposite thin films composed of monometallic Au and Ag, and bimetallic Au-Ag nanoparticles, dispersed in a CuO matrix, were prepared, characterized, and tested, which aimed to find suitable nano-plasmonic platforms capable of detecting the presence of gas molecules. The Localized Surface [...] Read more.
Magnetron sputtered nanocomposite thin films composed of monometallic Au and Ag, and bimetallic Au-Ag nanoparticles, dispersed in a CuO matrix, were prepared, characterized, and tested, which aimed to find suitable nano-plasmonic platforms capable of detecting the presence of gas molecules. The Localized Surface Plasmon Resonance phenomenon, LSPR, induced by the morphological changes of the nanoparticles (size, shape, and distribution), and promoted by the thermal annealing of the films, was used to tailor the sensitivity to the gas molecules. Results showed that the monometallic films, Au:CuO and Ag:CuO, present LSPR bands at ~719 and ~393 nm, respectively, while the bimetallic Au-Ag:CuO film has two LSPR bands, which suggests the presence of two noble metal phases. Through transmittance-LSPR measurements, the bimetallic films revealed to have the highest sensitivity to the refractive index changes, as well as high signal-to-noise ratios, respond consistently to the presence of a test gas. Full article
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Open AccessArticle
Epidemiology and Burden of Diabetic Foot Ulcer and Peripheral Arterial Disease in Korea
J. Clin. Med. 2019, 8(5), 748; https://doi.org/10.3390/jcm8050748 (registering DOI) -
Abstract
Information about the epidemiology of diabetic foot ulcer (DFU) with peripheral arterial disease (PAD) is likely to be crucial for predicting future disease progression and establishing a health care budget. We investigated the incidence and prevalence of DFU and PAD in Korea. In [...] Read more.
Information about the epidemiology of diabetic foot ulcer (DFU) with peripheral arterial disease (PAD) is likely to be crucial for predicting future disease progression and establishing a health care budget. We investigated the incidence and prevalence of DFU and PAD in Korea. In addition, we examined costs of treatments for DFU and PAD. This study was conducted using data from Health Insurance Review and Assessment Service from 1 January 2011 to 31 December 2016. The incidence of DFU with PAD was 0.58% in 2012 and 0.49% in 2016. The prevalence of DFU with PAD was 1.7% in 2011 to 1.8% in 2016. The annual amputation rate of DFU with PAD was 0.95% in 2012 and 1.10% in 2016. Major amputation was decreased, while minor amputation was increased. The direct cost of each group was increased, especially the limb saving group. which was increased from 296 million dollars in 2011 to 441 million dollars in 2016. The overall incidence of DFU with PAD was about 0.5% of total population in Korea, from 2012 to 2016. Furthermore, costs for treatments of diabetic foot ulcer are increasing, especially those for the limb saving group. Full article
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Open AccessArticle
Main Issues in Quality of Friction Stir Welding Joints of Aluminum Alloy and Steel Sheets
Metals 2019, 9(5), 610; https://doi.org/10.3390/met9050610 (registering DOI) -
Abstract
Joining of aluminum alloys through friction stir welding (FSW) is effectively employed in several industries (e.g., aeronautics and aerospace) since it guarantees proper weld strength as compared to other joining technologies. Contrarily, dissimilar FSW of aluminum alloys and steels often poses important issues [...] Read more.
Joining of aluminum alloys through friction stir welding (FSW) is effectively employed in several industries (e.g., aeronautics and aerospace) since it guarantees proper weld strength as compared to other joining technologies. Contrarily, dissimilar FSW of aluminum alloys and steels often poses important issues in the selection of welding parameters due to the difficulty to join different materials. Improper welding parameters give rise to the formation of intermetallic compounds, and internal and external defects (e.g., tunnel formation, voids, surface grooves, and flash). Intermetallic compounds are brittle precipitates of Al/Fe, which chiefly initiate crack nucleation, whereas internal and external defects mainly act as stress concentration factors. All these features significantly reduce joint strength under static and dynamic loading conditions. With reference to the literature, the influence of main welding parameters (rotational speed, welding speed, tool geometry, tilt angle, offset distance, and plunge depth) on the formation of intermetallic compounds and defects in FSW of aluminum alloys and steels is discussed here. Possible countermeasures to avoid or limit the above-mentioned issues are also summarily reported. Full article
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Open AccessArticle
An Evolutionary Yield Function Model Based on Plastic Work and Non-Associated Flow Rule
Metals 2019, 9(5), 611; https://doi.org/10.3390/met9050611 (registering DOI) -
Abstract
A constitutive law was developed based on the evolutionary yield function to account for the evolution of anisotropy induced by the plastic deformation. For the effective description of anisotropy, the yield stress function and plastic potential were separately defined based on the non-associated [...] Read more.
A constitutive law was developed based on the evolutionary yield function to account for the evolution of anisotropy induced by the plastic deformation. For the effective description of anisotropy, the yield stress function and plastic potential were separately defined based on the non-associated flow rule. In particular, for the description of the equivalent status, the accumulated plastic work was employed as an alternative to the accumulated plastic strain. Numerical formulations based on the plastic work were also derived in case the hardening rule, as well as the evolution of the plastic potential and yield stress function, were defined in terms of the plastic work. The developed constitutive law was characterized using the mechanical properties of the multi-phase BAO QP980 steel and niobium sheets at room temperature. From the uniaxial tension tests and the balanced biaxial tension test, separate sets of anisotropic coefficients for each of the plastic potential and yield stress functions were obtained as a function of the plastic work. By comparing with non-evolving yield functions, the importance of the developed constitutive law to properly describe the evolution of the plastic potential and yield function were validated. Full article

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