bluuebunny/crossref_metadata_2025 huggingface dataset:
Amphiphilic QP(DMAEMA-co-LMA)-b-POEGMA Random-Block Terpolymers as Nanocarriers for Insulin
Authors: Kafetzi Martha , Pispas Stergios , Bao Xiaoyan , Yao Ping
Published: October 2020

We report on the utilization of the amphiphilic poly[quaternized (2-(N,N-dimethylamino) ethyl methacrylate)]-co-(lauryl methacrylate))-b-poly[(oligo ethylene glycol) methyl ether methacrylate] QP(DMAEMA-co-LMA)-b-POEGMA cationic diblock terpolymer aggregates as nanocarriers for insulin delivery applications. QP(DMAEMA-co-LMA)-b-POEGMA random diblock terpolymer is derived from the chemical modification of the precursor amino diblock copolymer via quaternization, producing permanent positive charges on the macromolecular chain. The QP(DMAEMA-co-LMA)-b-POEGMA diblock terpolymer as well as its amino precursor investigated self-assemble in aqueous media, forming aggregates. In vitro cytotoxicity and in vivo biocompatibility studies on QP(DMAEMA-co-LMA)-b-POEGMA and its amino precursor aggregates, showed good cytocompatibility and biocompatibility. QP(DMAEMA-co-LMA)-b-POEGMA aggregates were chosen to be complexed with insulin due to their self-assembly features and the permanent positive charge in each amino group. QP(DMAEMA-co-LMA)-b-POEGMA aggregates were complexed with insulin through electrostatic interactions. Light scattering techniques were used in order to study the ability of the polymer aggregates to complex with insulin, to determine critical physicochemical parameters such as size, mass, and surface charge of the stable complexes and study the effect of salt addition on their properties. The results showed that in both cases, the complexation process was successful and as the insulin concentration increases, nanosized complexes of different physicochemical characteristics (mass, size, surface charge) and spherical morphology are formed. UV-Vis and fluorescence spectroscopy studies showed that no conformational changes of insulin occurred after the complexation.
Machine Learning to Improve the Sensing of Biomolecules by Conical Track-Etched Nanopore
Authors: Meyer Nathan , Janot Jean-Marc , Lepoitevin Mathilde , Smietana Michaël , Vasseur Jean-Jacques , Torrent Joan , Balme Sébastien
Published: October 2020

Single nanopore is a powerful platform to detect, discriminate and identify biomacromolecules. Among the different devices, the conical nanopores obtained by the track-etched technique on a polymer film are stable and easy to functionalize. However, these advantages are hampered by their high aspect ratio that avoids the discrimination of similar samples. Using machine learning, we demonstrate an improved resolution so that it can identify short single- and double-stranded DNA (10- and 40-mers). We have characterized each current blockade event by the relative intensity, dwell time, surface area and both the right and left slope. We show an overlap of the relative current blockade amplitudes and dwell time distributions that prevents their identification. We define the different parameters that characterize the events as features and the type of DNA sample as the target. By applying support-vector machines to discriminate each sample, we show accuracy between 50% and 72% by using two features that distinctly classify the data points. Finally, we achieved an increased accuracy (up to 82%) when five features were implemented.
Copper Complexes as Anticancer Agents Targeting Topoisomerases I and II
Authors: Molinaro Caroline , Martoriati Alain , Pelinski Lydie , Cailliau Katia
Published: October 2020

Organometallics, such as copper compounds, are cancer chemotherapeutics used alone or in combination with other drugs. One small group of copper complexes exerts an effective inhibitory action on topoisomerases, which participate in the regulation of DNA topology. Copper complexes inhibitors of topoisomerases 1 and 2 work by different molecular mechanisms, analyzed herein. They allow genesis of DNA breaks after the formation of a ternary complex, or act in a catalytic mode, often display DNA intercalative properties and ROS production, and sometimes display dual effects. These amplified actions have repercussions on the cell cycle checkpoints and death effectors. Copper complexes of topoisomerase inhibitors are analyzed in a broader synthetic view and in the context of cancer cell mutations. Finally, new emerging treatment aspects are depicted to encourage the expansion of this family of highly active anticancer drugs and to expend their use in clinical trials and future cancer therapy.
Investigation on Moisture Damage Prevention of a Spherical Hinge Structure of a Swivel Bridge
Authors: Guo Wei , Guo Xuedong , Wang Ziwen , Li Zhun
Published: October 2020

As a key component of a swivel bridge, the spherical hinge is a steel-concrete structure, which is susceptible to moisture damage during waiting time. In this paper, spherical hinge moisture damage prevention is investigated comprehensively from two aspects of impermeable concrete and steel-concrete interface waterproof coating. Three impermeable concretes were prepared and tested by the compressive strength test, splitting tensile test, four-point bending test and the impermeability test. The test results illustrated that addition of cementitious capillary crystalline active masterbatch (CCCAM) and polypropylene fiber (PP) could improve the toughness and brittleness of concrete. The addition of CCCAM was an effective technique for improving the permeability of concrete. However, the incorporation of PP and CCCAM at the same time cannot improve the impermeability of concrete. This may be because the chaotic support structure formed by PP prevents the infiltration and uniform dispersion of CCCAM. A waterproof coating consolidation performance test was proposed to quantify the interface bond strength of waterproof coatings and assess the impact of temperature, moisture and freeze-thawing cycles on consolidation performance of waterproof coatings. The test results showed that temperature had a significant effect on the interface consolidation property of waterproof coatings and the optimal dosage of SBS modified asphalt (SBS), polyurethane (PLT) and unsaturated polyester resin (UPLS) waterproof coating is 1.18kg/m2, 0.95kg/m2 and 1.15kg/m2, respectively. Moreover, it was found that PLS waterproof coating maintained excellent properties in complex environment. This is because PLS has excellent shear strength and rubber characteristics, and it can form a hard–soft–hard transition layer between the concrete and steel, reducing the impact of environmental factors.
Application of Infrared Spectroscopy in Prediction of Asphalt Aging Time History and Fatigue Life
Authors: Yan Yuan , Yang Yanmei , Ran Maoping , Zhou Xinglin , Zou Lanlin , Guo Minrui
Published: October 2020

Based on attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and principal component analysis (PCA), four kinds of asphalt (two kinds of matrix asphalts, TPC70# and JL70# and two kinds of modified asphalts, SBS-1 and SBS-2) were aged using the rolling thin-film oven test (RTFOT). The multiple stress repeated creep recovery test (MSCR) was carried out on an AR1500ex dynamic shear rheometer (DSR). The PCA was carried out on the attenuated total reflection infrared spectrum of a pretreated aged asphalt, the principal component factors (oxidation factor and component change factor) were determined, the comprehensive index F was calculated, and a prediction model of aging time history was established and verified. A prediction model for the aging asphalt recovery rate R was established based on the functional group index. The relationship between the recovery rate R and aging time history of each aging asphalt was analyzed and the fatigue life of each aging asphalt based on the rate of dissipated energy change (RDEC) was compared. The correlation between the comprehensive index F and fatigue life of asphalt was also analyzed. The results show that the order of resistance to the high-temperature deformation of each aging asphalt is as follows: SBS-2 > SBS-1 > TPC70# > JL70#; the prediction model of aging asphalt recovery rate R based on functional group index has good reliability. Taking the loading cycle corresponding to the sudden increase of the inflection point of the curve, i.e., the fatigue life NRDEC, as the evaluation index, the fatigue life order of each aging asphalt is SBS-1 > SBS-2 > JL70# > TPC70#. There is a positive correlation between the fatigue life of aged asphalt and the comprehensive index F of asphalt. The correlation degree R2 is 0.85; i.e., with the increase of the comprehensive index F of asphalt, its fatigue life also increases. It was found that it is feasible to analyze the aging time history and fatigue life of asphalt by infrared spectroscopy, and it can provide a rapid and non-destructive prediction method for the practical engineering application of asphalt.
Liver Biopsy Hydroxyproline Content Is a Diagnostic for Hepatocellular Carcinoma in Murine Models of Nonalcoholic Steatohepatitis
Authors: Bissoondial Tyler L. , Han Yiguang , Mullan Stephanie , Pabla Amrit K. , Spahn Kiera , Shi Steven , Zheng Lana , Zhou Ping , Jiang Kai , Prakash Natalia , Bhutkar Shraddha , Ali Quaisar , Li Jingsong , Hu Zhijian , Pellicano Anthony J. , Goldberg Itzhak D. , Narayan Prakash
Published: October 2020

There is increasing evidence that nonalcoholic steatohepatitis (NASH) is a risk factor for hepatocellular carcinoma (HCC) in the absence of cirrhosis, a phenomenon termed noncirrhotic HCC. Early diagnosis of HCC is critical to a favorable prognosis. We tested the hypothesis that hydroxyproline content of liver biopsy samples is diagnostic for HCC in murine models of NASH induced by diet or by diet and chemicals. The training set comprised mice fed a standard diet or a fast-food diet with or without administration of thioacetamide. At harvest, livers from the modified diet cohort exhibited NASH with a subset of NASH livers exhibiting HCC. Hydroxyproline content was measured in liver biopsy samples with tissue in the NASH+HCC cohort sampled from the remote, nontumor parenchyma. Plotting the receiver operating characteristics (ROC) with hydroxyproline as the continuous variable against the absence or presence of HCC yielded an area under ROC of 0.87, a threshold of >0.18 μg hydroxyproline/mg liver and sensitivity of 91% with a specificity of 83.3%. The use of liver hydroxyproline content as a diagnostic for HCC in a test set comprising healthy, NASH and NASH+HCC livers proved 87% accurate.
Local and Systemic Interleukin-32 in Esophageal, Gastric, and Colorectal Cancers: Clinical and Diagnostic Significance
Authors: Diakowska Dorota , Krzystek-Korpacka Małgorzata
Published: October 2020

Little is known on clinical and diagnostic relevance of interleukin-32 in gastrointestinal tract (GIT) cancers. We determined its mRNA (n = 52) and protein (n = 63) expression in paired (tumor-normal) samples from esophageal squamous cell carcinoma (ESCC) and gastric (GC) and colorectal cancer (CRC) patients, with reference to cancer-associated genes, and quantified circulating interleukin-32 in 70 cancer patients and 28 controls. IL32 expression was significantly upregulated solely in ESCC, reflecting T stage in non-transformed tumor-adjacent tissue. Fold-change in IL32 and IL-32 was higher in left-sided CRC, owing to high interleukin expression in non-transformed right-sided colonic mucosa. IL32 was independently and positively associated with Ki67, HIF1A, and ACTA2 and negatively with TJP1 in tumors and with IL10Ra and BCLxL in non-transformed tumor-adjacent tissue. IL-32 protein was significantly upregulated in colorectal tumors. In ESCC, advanced stage and lymph node metastasis were associated with significant IL-32 upregulation. Circulating interleukin was significantly elevated in cancer patients, more so in ESCC and GC than CRC. As biomarker, IL-32 detected gastroesophageal cancers with 99.5% accuracy. In conclusion, IL-32 is upregulated in GIT cancers at local and systemic level, reflecting hypoxia and proliferative and invasive/metastatic capacity in tumors and immunosuppressive and antiapoptotic potential in non-transformed mucosa, while being an accurate biomarker of gastroesophageal cancers.
Association between Clinical Signs of Oral Lichen Planus and Oral Health-Related Quality of Life: A Preliminary Study
Authors: Yiemstan Sasirin , Krisdapong Sudaduang , Piboonratanakit Pornpan
Published: October 2020

Subjective patient’s symptoms and Oral Health-Related Quality of Life (OHRQoL) are recommended to be involved in oral lichen planus (OLP) studies. This study aims to assess the OHRQoL of OLP patients, and their associations with pain and OLP in Thai patients. Sixty-nine patients were interviewed using the Numeric Rating Scale (NRS) for pain perception and Oral Impacts on Daily Performance (OIDP) index. OLP signs examined included localization, types, number of affected sides and clinical severity using the Thongprasom sign scoring system. There were significant associations (rs = 0.490, p < 0.001) between clinical severity and the intensity of oral impacts as well as pain (rs = 0.298, p = 0.013). The intensity of oral impacts and pain increased according to the increasing OLP clinical severity, except for the white striae lesions (Thongprasom sign score 1). The erosive/ulcerative OLP lesions (Thongprasom sign scores 4 and 5) were the most painful symptom and had the highest degree of oral impacts (p < 0.001). No significant associations were found between the number of affected lesion sides and OHRQoL (p = 0.316) and pain (p = 0.284). OHRQoL was associated with OLP type and clinical severity but not with the number of affected sides.
Comparison and Research on Diversified Portfolios with Several Entropy Measures Based on Different Psychological States
Authors: Deng Xue , Lin Tao , Chen Chuangjie
Published: October 2020

In previous studies, there were few portfolio models involving investors’ psychological states, market ambiguity and entropy. Some entropy can make the model have the effect of diversifying investment, which is very important. This paper mainly studies four kinds of entropy. First, we obtained four definitions of entropy from the literature, and gave the function of fuzzy entropy in different psychological states through strict mathematical proof. Then, we construct a fuzzy portfolio entropy decision model based on the investor’s psychological states, and compared it with the possibilistic mean–variance model. Then we presented a numerical example and compared the five different models established. By comparing the results, we find that: (a) The possibilistic mean–Shannon entropy model solves the problem of the possibility of excessive concentration in the possibilistic mean–variance model, but the dispersion is not enough. Conversely, the possibilistic mean–Yager entropy is over–emphasized due to the definition of its own function, such that it gave an investment pattern of equal weight distribution or approximate average distribution. (b) The results of possibilistic mean–proportional entropy can be said to be the middle status of the portfolios of possibilistic mean–Shannon entropy and possibilistic mean–Yager entropy. This portfolio not only achieves a certain rate of return, but also disperses the risk to some extent. (c) The lines of satisfaction for portfolios derived from different models are approximately U–shaped with the increase in return preference. (d) The possibilistic mean–Shannon entropy model tends to have the highest portfolio satisfaction with the same psychological state of the investor.
Complexity and Disorder of 1/fα Noises
Authors: Hsu Chang Francis , Hsu Long , Chi Sien
Published: October 2020

The complexity and the disorder of a 1/fα noise time series are quantified by entropy of entropy (EoE) and average entropy (AE), respectively. The resulting EoE vs. AE plot of a series of 1/fα noises of various values of α exhibits a distinct inverted U curve. For the 1/fα noises, we have shown that α decreases monotonically as AE increases, which indicates that α is also a measure of disorder. Furthermore, a 1/fα noise and a cardiac interbeat (RR) interval series are considered equivalent as they have the same AE. Accordingly, we have found that the 1/fα noises for α around 1.5 are equivalent to the RR interval series of healthy subjects. The pink noise at α = 1 is equivalent to atrial fibrillation (AF) RR interval series while the white noise at α = 0 is more disordered than AF RR interval series. These results, based on AE, are different from the previous ones based on spectral analysis. The testing macro-average F-score is 0.93 when classifying the RR interval series of three groups using AE-based α, while it is 0.73 when using spectral-analysis-based α.
Decision Tree Integration Using Dynamic Regions of Competence
Authors: Biedrzycki Jędrzej , Burduk Robert
Published: October 2020

A vital aspect of the Multiple Classifier Systems construction process is the base model integration. For example, the Random Forest approach used the majority voting rule to fuse the base classifiers obtained by bagging the training dataset. In this paper we propose the algorithm that uses partitioning the feature space whose split is determined by the decision rules of each decision tree node which is the base classification model. After dividing the feature space, the centroid of each new subspace is determined. This centroids are used in order to determine the weights needed in the integration phase based on the weighted majority voting rule. The proposal was compared with other Multiple Classifier Systems approaches. The experiments regarding multiple open-source benchmarking datasets demonstrate the effectiveness of our method. To discuss the results of our experiments, we use micro and macro-average classification performance measures.
Two-Phase Linear Hybrid Reluctance Actuator with Low Detent Force
Authors: Garcia-Amorós Jordi , Marín-Genescà Marc , Andrada Pere , Martínez-Piera Eusebi
Published: October 2020

In this paper, a novel two-phase linear hybrid reluctance actuator with the double-sided segmented stator, made of laminated U cores, and an interior mover with permanent magnets is proposed. The permanent magnets are disposed of in a way that increases the thrust force of a double-sided linear switched reluctance actuator of the same size. To achieve this objective, each phase of the actuator is powered by a single H-bridge inverter. To reduce the detent force, the upper and the lower stator were shifted. Finite element analysis was used to demonstrate that the proposed actuator has a high force density with low detent force. In addition, a comparative study between the proposed linear hybrid reluctance actuator, linear switched reluctance, and linear permanent magnet actuators of the same size was performed. Finally, experimental tests carried out in a prototype confirmed the goals of the proposed actuator.
Optimization of a Stirling Engine by Variable-Step Simplified Conjugate-Gradient Method and Neural Network Training Algorithm
Authors: Cheng Chin-Hsiang , Lin Yu-Ting
Published: October 2020

The present study develops a novel optimization method for designing a Stirling engine by combining a variable-step simplified conjugate gradient method (VSCGM) and a neural network training algorithm. As compared with existing gradient-based methods, like the conjugate gradient method (CGM) and simplified conjugate gradient method (SCGM), the VSCGM method is a further modified version presented in this study which allows the convergence speed to be greatly accelerated while the form of the objective function can still be defined flexibly. Through the automatic adjustment of the variable step size, the optimal design is reached more efficiently and accurately. Therefore, the VSCGM appears to be a potential and alternative tool in a variety of engineering applications. In this study, optimization of a low-temperature-differential gamma-type Stirling engine was attempted as a test case. The optimizer was trained by the neural network algorithm based on the training data provided from three-dimensional computational fluid dynamic (CFD) computation. The optimal design of the influential parameters of the Stirling engine is yielded efficiently. Results show that the indicated work and thermal efficiency are increased with the present approach by 102.93% and 5.24%, respectively. Robustness of the VSCGM is tested by giving different sets of initial guesses.
Characteristics of Gel Time and Dielectric Strength of Epoxy Composite According to the Mixing Ratio of Micro-Fillers
Authors: Oh Dong-Hun , Kim Ho-Seung , Shim Jae-Hun , Jeon Young-Ho , Kang Da-Won , Lee Bang-Wook
Published: October 2020

The dielectric strength and gel time of epoxy composites vary with the mixing ratio of epoxy resin, hardener, additives, filler, etc., and especially the gel time affects the productivity and economics of ultra-high-voltage (UHV) equipment. However, previous studies focused only on the dielectric strength of epoxy composites for the reliability of UHV equipment. Therefore, a study considering both the dielectric strength and gel time of the epoxy composite is required. In this paper, the characteristics of the gel time and dielectric strength of the epoxy micro-composites according to the mixing ratio of silica (SiO2) and alumina (Al2O3) micro-fillers without changing the mixing ratio of epoxy resin and hardener are analyzed. Experimental results show that the gel time decreased and the dielectric strength increased as the mixing ratio of the SiO2 micro-filler increased. Therefore, it is concluded that the gel time can be controlled by changing the mixing ratio of micro-fillers without changing the mixing ratio of the epoxy resin and hardener. In addition, experimental data can be used as basic data for economical production considering both the reliability and productivity of UHV power equipment.
Circular Economy in Poland: Profitability Analysis for Two Methods of Waste Processing in Small Municipalities
Authors: Zaleski Przemysław , Chawla Yash
Published: October 2020

The problem of diminishing resources on our plant is now getting due attention from the governments as well as scientists around the world. The transition from a linear economy to a circular economy (CE) is now among the top priorities. This article discusses the implementation of the circular economy paradigm in Poland through the analysis of the existing and planned mechanisms, and actions taken by the Polish government which can be replicated by other young European countries. Further, the article discusses the direction of change and projected measures planned by the Polish government to improve the quality of municipal solid waste management. In this context, profitability analysis is carried out for two methods of waste processing (incineration and torrefaction) intended for small municipalities and settlements in which district heating and trading of generated electricity are not feasible. The results of the analysis shows that torrefaction is clearly a more desirable waste processing option as a step towards the implementation of CE for civic society in the urban context, as well as profitability, in comparison to incineration. The analysis accounts for several scenarios before the lockdown caused due to the COVID-19 pandemic and after it was lifted.
NSGA-II-Based Codesign Optimization for Power Conversion and Controller Stages of Interleaved Boost Converters in Electric Vehicle Drivetrains
Authors: Tran Dai-Duong , Chakraborty Sajib , Lan Yuanfeng , Baghdadi Mohamed El , Hegazy Omar
Published: October 2020

This article proposes a holistic codesign optimization framework (COF) to simultaneously optimize a power conversion stage and a controller stage using a dual-loop control scheme for multiphase SiC-based DC/DC converters. In this study, the power conversion stage adopts a non-isolated interleaved boost converter (IBC). Besides, the dual-loop control scheme uses type-III controllers for both inner- and outer- loops to regulate the output voltage of the IBC and tackle its non-minimum phase issue. Based on the converter architecture, a multi-objective optimization (MOO) problem including four objective functions (OFs) is properly formulated for the COF. To this end, total input current ripple, total weight of inductors and total power losses are selected as three OFs for the power conversion stage whilst one OF called integral of time-weighted absolute error is considered for the controller stage. The OFs are expressed in analytical forms. To solve the MOO problem, the COF utilizes a non-dominated sorted genetic algorithm (NSGA-II) in combination with an automatic decision-making algorithm to obtain the optimal design solution including the number of phases, switching frequency, inductor size, and the control parameters of type-III controllers. Furthermore, compared to the conventional ‘k-factor’ based controller, the optimal controller exhibits better dynamic responses in terms of undershoot/overshoot and settling time for the output voltage under load disturbances. Moreover, a liquid-cooled SiC-based converter is prototyped and its optimal controller is implemented digitally in dSPACE MicroLabBox. Finally, the experimental results with static and dynamic tests are presented to validate the outcomes of the proposed COF.
Monte Carlo Investigation of the UK’s First EPR Nuclear Reactor Startup Core Using Serpent
Authors: Li Jinfeng
Published: October 2020

Computationally modelling a nuclear reactor startup core for a benchmark against the existing models is highly desirable for an independent assessment informing nuclear engineers and energy policymakers. For the first time, this work presents a startup core model of the UK’s first Evolutionary Pressurised Water Reactor (EPR) based on Monte Carlo simulations of particle collisions using Serpent 2, a state-of-the-art continuous-energy Monte Carlo reactor physics burnup code. Coupling between neutronics and thermal-hydraulic conditions with the fuel depletion is incorporated into the multi-dimensional branches, obtaining the thermal flux and fission reaction rate (power) distributions radially and axially from the three dimensional (3D) single assembly level to a 3D full core. Shannon entropy is quantified to characterise the convergence behaviour of the fission source distribution, with 3 billion neutron histories tracked by parallel computing. Source biasing is applied for the variance reduction. Benchmarking the proposed Monte Carlo 3D full-core model against the traditional deterministic transport computation suite used by the UK Office for Nuclear Regulation (ONR), a reasonably good agreement within statistics is demonstrated for the safety-related reactivity coefficients, which creates trust in the EPR safety report and informs the decision-making by energy regulatory bodies and global partners.
Micro Nuclear Reactors: Potential Replacements for Diesel Gensets within Micro Energy Grids
Authors: Gabbar Hossam A. , Abdussami Muhammad R. , Adham Md. Ibrahim
Published: October 2020

Resilient operation of medium/large scale off-grid energy systems, which is a key challenge for energy crisis solutions, requires continuous and sustainable energy resources. Conventionally, micro energy grids (MEGs) are adopted to supply electricity and thermal energy simultaneously. Fossil-fired gensets, such as diesel generators, are indispensable components for off-grid MEGs due to the intermittent nature of renewable energy sources (RESs). However, fossil-fired gensets emit a significant amount of greenhouse gases (GHGs). Therefore, this study investigates an alternative source as an economical and environmental replacement for diesel gensets that can reduce GHG emissions and ensure system reliability. A MEG is developed in this paper to support a considerably large-scale electric and thermal demand at Ontario Tech University (UOIT). Different sizes of diesel gensets and RESs, such as solar, wind, hydro, and biomass, are combined in the MEG for off-grid applications. To evaluate diesel gensets’ competency, the diesel genset is substituted by an emission-free generation source named microreactor (MR). The fossil-fired MEG and MR-based MEG are optimized by an intelligent optimization technique, namely particle swarm optimization (PSO). The objective of the PSO is to minimize the net present cost (NPC). The simulation results show that MR-based MEG could be an excellent replacement for a diesel genset in terms of NPC and selected key performance indicators (KPIs). A comprehensive sensitivity analysis is also carried out to validate the simulation results.
Modeling and Experimental Investigation of Electromagnetic Interference (EMI) for SiC-Based Motor Drive
Authors: Wu Yingzhe , Yin Shan , Li Hui , Dong Minghai
Published: October 2020

The motor drive has been widely adopted in modern power applications. With the emergency of the next generation wide bandgap semiconductor device, such as silicon carbide (SiC) MOSFET, performance of the motor drive can be improved in terms of efficiency, power density, and reliability. However, the fast switching transient and serious switching ringing of the SiC MOSFET can cause unwanted high-frequency (HF) electromagnetic interference (EMI), which may significantly reduce the reliability of the motor drive in many aspects. In order to comprehensively reveal the mechanism of the EMI previously used in motor drives using SiC MOSFET, this paper plans to analyze the influences of both HF impedance of the motor and switching characteristics of the SiC MOSFET. A simulation model for motor drives has been proposed, which contains the HF circuit model of the motor as well as a semi-behavioral analytical model of the SiC MOSFET. Since the model shows a good agreement with the experimentally measured results on spectra of drain-source voltage of the SiC MOSFET (vds), phase to ground voltage of the motor (vphase), CM voltage (vcm), phase current of the motor (idm), and CM current (icm), it can be adopted to quantitatively investigate the influence of the motor impedance on EMI through frequency-domain analysis. Additionally, the impacts of switching characteristics of SiC MOSFET on EMI are also well studied according to relative experiment results in terms of switching speed, switching frequency, and switching ringing. Based on the analysis above, the relationship between motor impedance, switching characteristics of the SiC MOSFET, and HF EMI can be figured out, which is able to provide much helpful assistance for application of the motor drive.
Transfer Characteristics of the Nonlinear Parity-Time-Symmetric Wireless Power Transfer System at Detuning
Authors: Li Changsheng , Dong Wenjie , Ding Libo , Zhang He , Sun Hang
Published: October 2020

The nonlinear parity-time-symmetric wireless power transfer (NPTS-WPT) system is more robust against transfer distance than the traditional WPT system. Current studies mainly focus on the situation in which the transmitter (Tx) and the receiver (Rx) are completely matched. Our study focuses on the transfer characteristics of the NPTS-WPT system under detuning between the Tx and the Rx. First, the mathematical model of the detuned system is established, and then the model is solved using Shengjin’s formula. Then, the exact analytical solutions for the operating frequency, the amplification factor of the operational amplifier (OP Amp) and the transfer efficiency at detuning are obtained. It was noted, for the first time, that even though the Tx and the Rx were completely matched, a frequency jump could occur when the distance between the Tx and Rx coils slowly changed. Our study found that when the degree of detuning of the system changed, the operating frequency of the system could jump. By investigating the amplification factor of the OP Amp, the reason for the frequency jump when the system was detuned was explained. Our study also revealed that detuning did not imply a decreased transfer efficiency, and the over-detuning can improve the transfer efficiency sometimes. Finally, an experimental system was constructed, and the correctness of the theory was validated using the experimental system.
Towards the Design of P2P Energy Trading Scheme Based on Optimal Energy Scheduling for Prosumers
Authors: Chung Koo-Hyung , Hur Don
Published: October 2020

The peer-to-peer (P2P) energy trading is anchored in more efficient usage of electric power by allowing excess electric power from energy prosumers to be harnessed by other end-users. To boost the P2P energy trading, it is of pivotal significance to call on energy prosumers and end-users to actively participate in the trading while sharing information with a greater degree of freedom. In this perspective, this paper purports to implement the P2P energy trading scheme with an optimization model to assist in energy prosumers’ decisions by reckoning on hourly electric power available in the trading via the optimal energy scheduling of the energy trading and sharing system (ETS). On a purely practical level, it is assumed that all trading participants neither join the separate bidding processes nor are forced to comply with the predetermined optimal schedules for a trading period. Furthermore, this paper will be logically elaborated with reference to not only the determination of transaction price for maximizing the benefits of consumers under the different electricity rates but the establishment of additional settlement standards for bridging an imperative gap between optimally planned and actually transacted quantities of the P2P energy trading.
Thermodynamic and Cost Analysis of a Solar Dish Power Plant in Spain Hybridized with a Micro-Gas Turbine
Authors: García-Ferrero Judit , Heras Irene , Santos María Jesús , Merchán Rosa Pilar , Medina Alejandro , González Antonio , Calvo Hernández Antonio
Published: October 2020

Small-scale hybrid parabolic dish concentrated solar power systems are a promising option to obtain distributed electricity. During the day, solar energy is used to produce electricity, and the absence of sunlight can be overwhelmed with fuel combustion. This study presents a thermo-economic survey for a hybridized power plant in different regions of Spain, considering the local climatic conditions. The developed model considers the instant solar irradiance and ambient temperature dynamically, providing an estimation of the power output, the associated fuel consumption, and the most relevant pollutant emissions linked to combustion. Hybrid and combustion-only operating modes at selected geographical locations in Spain (with different latitudes, mean solar irradiances, and meteorological conditions) are analyzed. The levelized cost of electricity indicator is estimated as a function of investment, interest rate, maintenance, and fuel consumption actual costs in Spain. Values of about 124 €/MWhe are feasible. Fuel consumption and emissions in hybrid operation can be reduced above 30% with respect to those of the same turbine working in a pure combustion mode. This model shows the potential of hybrid solar dishes to become cost-competitive against non-renewable technologies from the point of view of costs and reduction in gas emission levels in regions with high solar radiation and low water resources.
A Novel Single-Wire Power Transfer Method for Wireless Sensor Networks
Authors: Li Yang , Wang Rui , Zhai Yu-Jie , Li Yao , Ni Xin , Ma Jingnan , Liu Jiaming
Published: October 2020

Wireless sensor networks (WSNs) have broad application prospects due to having the characteristics of low power, low cost, wide distribution and self-organization. At present, most the WSNs are battery powered, but batteries must be changed frequently in this method. If the changes are not on time, the energy of sensors will be insufficient, leading to node faults or even networks interruptions. In order to solve the problem of poor power supply reliability in WSNs, a novel power supply method, the single-wire power transfer method, is utilized in this paper. This method uses only one wire to connect source and load. According to the characteristics of WSNs, a single-wire power transfer system for WSNs was designed. The characteristics of directivity and multi-loads were analyzed by simulations and experiments to verify the feasibility of this method. The results show that the total efficiency of the multi-load system can reach more than 70% and there is no directivity. Additionally, the efficiencies are higher than wireless power transfer (WPT) systems under the same conductions. The single-wire power transfer method could satisfy the characteristics of WSNs and effectively solve the problem of poor power supply reliability.
Aerodynamic Study of the Wake Effects on a Formula 1 Car
Authors: Guerrero Alex , Castilla Robert
Published: October 2020

The high complexity of current Formula One aerodynamics has raised the question of whether an urgent modification in the existing aerodynamic package is required. The present study is based on the evaluation and quantification of the aerodynamic performance on a 2017 spec. adapted Formula 1 car (the latest major aerodynamic update) by means of Computational Fluid Dynamics (CFD) analysis in order to argue whether the 2022 changes in the regulations are justified in terms of aerodynamic necessities. Both free stream and flow disturbance (wake effects) conditions are evaluated in order to study and quantify the effects that the wake may cause on the latter case. The problem is solved by performing different CFD simulations using the OpenFoam solver. The significance and originality of the research may dictate the guidelines towards an overall improvement of the category and it may set a precedent on how to model racing car aerodynamics. The studied behaviour suggests that modern F1 cars are designed and well optimised to run under free stream flows, but they experience drastic aerodynamic losses (ranging from −23% to 62% in downforce coefficients) when running under wake flows. Although the overall aerodynamic loads are reduced, there is a fuel efficiency improvement as the power that is required to overcome the drag is smaller. The modern performance of Ground Effect by means of vortices management represent a very unique and complex way of modelling modern aerodynamics, but at the same time notably compromises the performance of the cars when an overtaking maneuver is intended.
Analysis of AMI Communication Methods in Various Field Environments
Authors: Kim Dong Sik , Chung Beom Jin , Chung Young Mo
Published: October 2020

In order to construct an efficient on-site communication network for an advanced metering infrastructure (AMI) in Korea, the high-speed power line communication (HS PLC), wireless smart utility network (Wi-SUN), and ZigBee modems are currently being used. In this paper, we first quantitatively analyze the communication performances of HS PLC, Wi-SUN, and ZigBee modems for AMI through both experimental testbeds and practical environment sites. For practical AMI sites, we selected 18 sites with 48 measurement points and classified the sites into five areas, and conducted measurements of signal and noise power spectra on the sites. We then derived linear regression models for received powers according to areas. Through the constructed models, we can efficiently choose an appropriate communication method and plan a methodology for building an AMI network depending on the area type. Furthermore, using the constructed regression models, we provided graphical simulation tools of received powers for both PLC and wireless communication methods based on a distribution information map.
Combustion Modeling and Simulation of Recycled Anode-off-Gas from Solid Oxide Fuel Cell
Authors: Kashmiri Sataish Asghar , Tahir Muhammad Wasim , Afzal Umer
Published: October 2020

A solid oxide fuel cell (SOFC) is popular amongst other fuel cell technologies due to fuel flexibility, low cost, and stability. Because of difficulties involved in the handling of hydrogen, onsite hydrogen production is considered for many small- and large-scale applications. It involves an integrated setup consisting of a reformer, combustor, and fuel cell stack. Being operated at high temperature, gases leaving SOFC contain a significant amount of thermal energy which can be utilized within the integrated reforming process. In addition, anode-off-gas (AOG) from SOFC contains unreacted hydrogen which can be utilized as fuel in an integrated combustor thereby increasing combustor efficiency. For effective integration of a combustor, reformer, and power generator, modeling and simulation is of great utility. In the present work, a 3D model of an integrated combustor unit is developed and implemented into the computational fluid dynamics (CFD) simulation package ANSYS FLUENT®. Main objective of this work is to prove the concept of enhancement in combustor performance by utilizing AOG from SOFC as a supplementary fuel in the combustor. Simulation results show a significant increase in combustor temperature and heat dissipated to the reformer side with AOG utilization. Up to an 18% saving in fuel (natural gas), used in combustor to supply heat to the reformer, is observed.
Electricity Price Forecasting Based on Self-Adaptive Decomposition and Heterogeneous Ensemble Learning
Authors: Ribeiro Matheus , Stefenon Stéfano , de Lima José , Nied Ademir , Mariani Viviana , Coelho Leandro
Published: October 2020

Electricity price forecasting plays a vital role in the financial markets. This paper proposes a self-adaptive, decomposed, heterogeneous, and ensemble learning model for short-term electricity price forecasting one, two, and three-months-ahead in the Brazilian market. Exogenous variables, such as supply, lagged prices and demand are considered as inputs signals of the forecasting model. Firstly, the coyote optimization algorithm is adopted to tune the hyperparameters of complementary ensemble empirical mode decomposition in the pre-processing phase. Next, three machine learning models, including extreme learning machine, gradient boosting machine, and support vector regression models, as well as Gaussian process, are designed with the intent of handling the components obtained through the signal decomposition approach with focus on time series forecasting. The individual forecasting models are directly integrated in order to obtain the final forecasting prices one to three-months-ahead. In this case, a grid of forecasting models is obtained. The best forecasting model is the one that has better generalization out-of-sample. The empirical results show the efficiency of the proposed model. Additionally, it can achieve forecasting errors lower than 4.2% in terms of symmetric mean absolute percentage error. The ranking of importance of the variables, from the smallest to the largest is, lagged prices, demand, and supply. This paper provided useful insights for multi-step-ahead forecasting in the electrical market, once the proposed model can enhance forecasting accuracy and stability.
Management of the Energy Mix and Emissivity of Individual Economies in the European Union as a Challenge of the Modern World Climate
Authors: Miciuła Ireneusz , Wojtaszek Henryk , Bazan Marek , Janiczek Tomasz , Włodarczyk Bogdan , Kabus Judyta , Kana Radomir
Published: October 2020

The aim of the article is to present the most important elements to be implemented in the European Union energy policy in the 2030 perspective in the context of sustainable development of the Member States. The solution to the too high emissivity of individual economies in the European Union is the energy mix, which will establish a compromise in the so-called the triad of EU policy goals. This is undoubtedly a current climate challenge for the modern world, which also has a direct impact on the economic situation of EU countries. The basis of the presented considerations and recommendations is a literature review on the subject and a statistical analysis of empirical data of the largest statistical organizations in the EU and the world. The starting point for the analysis is the assessment of the state of the energy sector in the EU. Therefore, the goals and tasks until 2030 result from many conditions of the energy sector. The article provides recommendations for the EU on future climate and energy policy, analysing the practices of member countries empirical and data compiled by the world’s largest organizations and institutions, such as the International Atomic Energy Agency (IAEA), the World Nuclear Association (WNA), Eurostat, and the International Energy Agency (IEA). The strategic goals of the EU climate and energy policy presented in the study show the necessary challenges for the implementation of sustainable development in the analyzed sector, which is the driving force of world economies. The conclusions were presented in accordance with the current economic efficiency of various energy sources and the necessity to seek a compromise among the so-called a triad of goals defined in EU policy.
Impact of Body Mass Index on Activities of Daily Living in Patients with Idiopathic Interstitial Pneumonias
Authors: Shirado Kengo , Wakabayashi Hidetaka , Maeda Keisuke , Momosaki Ryo
Published: October 2020

In patients with idiopathic interstitial pneumonias, undernutrition has a profound effect on prognosis. However, whether body mass index affects the ability to perform activities of daily living as measured by the Barthel index in patients with idiopathic interstitial pneumonias remains unknown. Therefore, we examined the impact of body mass index on the activities of daily living in inpatients with idiopathic interstitial pneumonia. We used a database constructed by the Japan Medical Data Center. Data were extracted from 2774 inpatients from participating hospitals with a diagnosis of idiopathic interstitial pneumonia. Multiple regression analysis adjusted for confounding factors was performed to determine whether body mass index classification would be independently related to change in Barthel index during hospitalization. Underweight, normal weight, overweight, and obesity numbered 473 (19%), 1037 (41), 795 (31%), and 235 (9%), respectively. Multivariable analysis showed that being underweight was independently associated with a change in Barthel index during hospitalization of −2.95 (95% confidence interval −4.82 to −1.07) points lower than being normal weight. Approximately 20% of the patients with idiopathic interstitial pneumonias were underweight. Those who were underweight had decreased independence in activities of daily living during hospitalization.