bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency of bystander exposure to antibiotics for enteropathogenic bacteria among young children in low-resource settings
Authors: Rogawski McQuade Elizabeth T. , Brennhofer Stephanie A. , Elwood Sarah E. , McMurry Timothy L. , Lewnard Joseph A. , Mduma Estomih R. , Shrestha Sanjaya , Iqbal Najeeha , Bessong Pascal O. , Kang Gagandeep , Kosek Margaret , Lima Aldo A. M. , Ahmed Tahmeed , Liu Jie , Houpt Eric R. , Platts-Mills James A.
Published: August 2022

Children in low-resource settings carry enteric pathogens asymptomatically and are frequently treated with antibiotics, resulting in opportunities for pathogens to be exposed to antibiotics when not the target of treatment (i.e., bystander exposure). We quantified the frequency of bystander antibiotic exposures for enteric pathogens and estimated associations with resistance among children in eight low-resource settings. We analyzed 15,697 antibiotic courses from 1,715 children aged 0 to 2 y from the MAL-ED birth cohort. We calculated the incidence of bystander exposures and attributed exposures to respiratory and diarrheal illnesses. We associated bystander exposure with phenotypic susceptibility of E. coli isolates in the 30 d following exposure and at the level of the study site. There were 744.1 subclinical pathogen exposures to antibiotics per 100 child-years. Enteroaggregative
Escherichia coli
was the most frequently exposed pathogen, with 229.6 exposures per 100 child-years. Almost all antibiotic exposures for
Campylobacter
(98.8%), enterotoxigenic
E. coli
(95.6%), and typical enteropathogenic
E. coli
(99.4%), and the majority for
Shigella
(77.6%), occurred when the pathogens were not the target of treatment. Respiratory infections accounted for half (49.9%) and diarrheal illnesses accounted for one-fourth (24.6%) of subclinical enteric bacteria exposures to antibiotics. Bystander exposure of
E. coli
to class-specific antibiotics was associated with the prevalence of phenotypic resistance at the community level. Antimicrobial stewardship and illness-prevention interventions among children in low-resource settings would have a large ancillary benefit of reducing bystander selection that may contribute to antimicrobial resistance.
A protein of capillary endothelial cells, GPIHBP1, is crucial for plasma triglyceride metabolism
Authors: Young Stephen G. , Song Wenxin , Yang Ye , Birrane Gabriel , Jiang Haibo , Beigneux Anne P. , Ploug Michael , Fong Loren G.
Published: August 2022

GPIHBP1, a protein of capillary endothelial cells (ECs), is a crucial partner for lipoprotein lipase (LPL) in the lipolytic processing of triglyceride-rich lipoproteins. GPIHBP1, which contains a three-fingered cysteine-rich LU (Ly6/uPAR) domain and an intrinsically disordered acidic domain (AD), captures LPL from within the interstitial spaces (where it is secreted by parenchymal cells) and shuttles it across ECs to the capillary lumen. Without GPIHBP1, LPL remains stranded within the interstitial spaces, causing severe hypertriglyceridemia (chylomicronemia). Biophysical studies revealed that GPIHBP1 stabilizes LPL structure and preserves LPL activity. That discovery was the key to crystallizing the GPIHBP1–LPL complex. The crystal structure revealed that GPIHBP1’s LU domain binds, largely by hydrophobic contacts, to LPL’s C-terminal lipid-binding domain and that the AD is positioned to project across and interact, by electrostatic forces, with a large basic patch spanning LPL’s lipid-binding and catalytic domains. We uncovered three functions for GPIHBP1’s AD. First, it accelerates the kinetics of LPL binding. Second, it preserves LPL activity by inhibiting unfolding of LPL’s catalytic domain. Third, by sheathing LPL’s basic patch, the AD makes it possible for LPL to move across ECs to the capillary lumen. Without the AD, GPIHBP1-bound LPL is trapped by persistent interactions between LPL and negatively charged heparan sulfate proteoglycans (HSPGs) on the abluminal surface of ECs. The AD interrupts the HSPG interactions, freeing LPL–GPIHBP1 complexes to move across ECs to the capillary lumen. GPIHBP1 is medically important;
GPIHBP1
mutations cause lifelong chylomicronemia, and GPIHBP1 autoantibodies cause some acquired cases of chylomicronemia.
Proxy-based sliding-mode tracking control of dielectric elastomer actuators through eliminating rate-dependent viscoelasticity
Authors: Zou Jiang , MacLean James D J , Ren Jieji , Aphale Sumeet S , Gu Guoying
Published: August 2022

Dielectric elastomer actuators (DEAs) usually suffer from rate-dependent viscoelastic nonlinearity, which manifests as hysteresis in their deformation cycles, leading to huge challenges in their modeling and control. In this work, we propose a model-free, proxy-based, sliding-mode tracking control approach to mitigate viscoelastic nonlinearity, achieving high-precision tracking control of DEAs. To this end, we first investigate the viscoelastic nonlinearity of DEAs, revealing its asymmetric and rate-dependent characteristics. Then, by combining the benefits of the PID control for small positioning errors and sliding-mode control for large errors, a proxy-based, sliding-mode tracking controller (PBSMC) is established. Finally, the stability of the controller is analyzed. To verify the effectiveness of the controller, several experiments are conducted to demonstrate the performance of DEAs in tracking sinusoidal trajectories under different frequencies. The experimental results demonstrate that with the PBSMC, the DEA can precisely track sinusoidal trajectories within a frequency range of 0.1 Hz–4.0 Hz by effectively minimizing the effect of inherent viscoelastic nonlinearity. Compared with open-loop tracking performance, the proxy-based, sliding-mode controlled DEA shows a significant reduction in maximum tracking errors from 45.87% to 8.72% and in root-mean-square errors from 24.46% to 3.88%. The main advantages of the proxy-based, sliding-mode control are: (a) it adopts a model-free approach, avoiding the need for complex dynamic modeling; (b) it can achieve high-precision tracking control of DEAs, thereby paving the way for the adoption of DEAs in several emerging applications.
Numerical Investigation on the Effect of the Diversion Layer on the Flow Field of the α-Type Cyclone Separator
Authors: Fan J L , Li W H , Zhang P , Chen G H
Published: August 2022

The flow field stability and separation performance of the cyclone separator decrease significantly as its size increases. An inner guider was added in α-type cyclone separator, and in this paper, a numerical investigation on the gas-solid two-phase flow in the α-type cyclone was conducted. The Reynolds stress model and the DPM model were used to simulate the gas flow and the motion of particles, respectively. The influence of the guider on the velocity field, pressure field, turbulent kinetic energy field, and particle separation efficiency of the cyclone separator was analyzed. The results showed that after adding an inner guider, the tangential velocity increases, the turbulent kinetic energy decreases, the downward area of the axial airflow increases, and the number of airflow-carrying particles downward increases.
A Method for Obtaining Solution of the Spatial Optical Soliton Based on the Adomian Decomposition Method
Authors: Cai Yungao
Published: August 2022

For obtaining the solution of the spatial optical solution in the nonlinear Schrödinger equation, the aomian decomposition method was used for solving the complex equation. The specific process for solving had four steps. Firstly, the nonlinear equation was appropriately decomposed into several parts and the solution also was decomposed into infinite parts. Secondly, the special aomian polynomial that equaled to the nonlinear term was produced. Thirdly, the high order components were obtained by the low order components with the inverse operator. Finally, the sum of the components that was the approximation solution was obtained. The sum of the real part (the imaginary part) of the front five items by aomian decomposition method was approximation to that of exact solution respectively. The results show that the aomian decomposition method has the characteristics of the fast convergence and the high accuracy. The aomian decomposition method was an important method for solving the spatial solution
Numerical Simulation of Flow Past Circular Cylinder Based on Overset Grid Method
Authors: Song Liwei
Published: August 2022

Based on overset grid method, the problems about flow past circular cylinder were numerically studied, which include the flow around a single circular cylinder at Reynolds number Re=100 and Reynolds number Re=200, the flow past two tandem circular cylinders at Reynolds number Re=200 and dimensionless distance g*=4, and the flow around a lateral oscillating circular cylinder at Reynolds number Re=200. Overset grid method is effective in dealing with the problems of flow over multi-body and flow with moving boundaries. This grid method couple overlapping regions in an arbitrary manner through flow field information updating over acceptor cells in one region suing its donor cells in another region. The computed drag coefficient and lift coefficients of the circular cylinder, vortical structure in the flow wake and vortex shedding P+S mode are agreed well with the results in previous experiment investigations and numerical simulations.
Particle Number Measurement and Its Numerical Simulation of the Airborne Particle Counter by ‘Post-Collection-Check’
Authors: Gao Z L , Zeng G L , Cheng Q D , Wang R J , Zhang W H , Wang F Q , Chen J , Wu J P , Guo J
Published: August 2022

The measurement results of the light-scattering airborne particle counter can effectively evaluate the concentration of airborne particles in the clean environment and confined space, and the accuracy improvement of the calibration measurement results has attracted more and more attention. This paper introduces the ‘post-collection-check’ way of the airborne particle concentration measurement method of the OPC (Optical Particle Counter), based on FESEM (Field Emission Scanning Electron Microscopy) and AAO (Anodic Aluminum Oxide) template, the probability distribution of the collected PSL (Polystyrene Latex) particles on the surface of AAO template, and the pressure parameters of AAO template under the different particle over current areas are both simulated. The numerical simulation results will help to improve the accuracy of the inference statistics of the collected PSL particle number on the membrane filter, and to give guidance on the optimal design of the PSL particle collection tube and the membrane filter, in order to provide an important reference for further improving the OPC particle concentration calibration and traceability method based on statistical theory.
Research on Momentum Parameters of Tailings Dam-break Mortar
Authors: Zhou Hongkang , Liu Yanzhang , Shan Liang , Wang Wenjie , Cao Huabing
Published: August 2022

The tailings dam-break mortar with high potential energy will cause impact damage to the downstream buildings, and the momentum parameters of mortar can effectively reflect its impact on buildings. Taking the distribution status of downstream geomorphology and production and living facilities of Yangjiawan tailing pond as the calculation background, Numbering 4 sensitive analysis points from 1 to 4 in line with the distance between the key protected structures and the breach of the tailing pond from the near to the distant, The three-dimensional fluid simulation software FLOW 3D was used to simulate the evolution process of dam-break mortar under the full-break condition of the accumulation dam above the initial dam, and the variation characteristics of the flow mortar momentum at the key protection structures in the evolution process were analyzed. The results show that the momentum of dam-break mortar at the sensitive points decreases from the near to the distant, Compared with instantaneous momentum, cumulative momentum could reflect the cumulative impact effect of mortar on buildings, and the distinction of impact effect was more obvious.; The peak inundation depth of dam-break mortar at each sensitive point was 1, 3, 2 and 4 sensitive points in descending order, the momentum and submergence depth were inconsistent, The momentum could clearly distinguish the difference of mortar impact effect, and the research results could provide some reference for dam - breaking mortar disaster assessment of tailing pond
Efficient Shock Capturing Based on Parallel Adaptive Mesh Refinement Framework
Authors: Li Weihao , Xia Jian
Published: August 2022

Based on AMReX, a software framework for massively parallel, block-structured adaptive mesh refinement (AMR) applications and in combination with finite difference weighted essential non-oscillatory (WENO) method, a numerical procedure is developed to provide universal discontinuity capturing capability for inviscid, compressible flow. Test cases of one-dimensional and two-dimensional flows containing shock waves, contact discontinuities, flow instabilities, and their interactions are considered to validate the high resolution of AMR for characteristic flow structure under unsteady conditions. The current elaborate AMR-based code is proven to have superior efficiency relative to global refinement via experiments including different initial mesh intervals, refinement ratios at all levels, and. Evidence in executions with multiple processes and domain division sizes indicates its high parallel scalability. Thus, the application built on AMReX is promising for simulations of phenomena undergoing rapid local variation such as compressible turbulence and multiphase interactions.
Study on Impeller Configuration Strategy of Dredger Pump with Different Conveying Distance
Authors: Zhuang Haifei , Liu Mingming , Wu Yongding
Published: August 2022

For DN850 dredge pumps of 3,500 m3/h series cutter suction dredger, on the premise of not changing the impeller size, by changing the parameters of impeller blade to reduce the head of dredge pump, special new impellers for inboard pump and submerged pump are designed; The flow field of the dredge pump is analyzed by numerical simulation. There is no vortex in the impeller channel and near volute tongue, which indicates that the hydraulic performance is excellent; At the flow rate of 10,000 m3/h, compared with the original impeller, the head of the two pumps in series with new impellers is reduced by 23 m, and the efficiency is close to that before modification, reaching more than 85%; This paper analyzes the matching between the dredger pump and the pipeline under three kinds of common sandy mud. By comparing the unit power consumption and productivity, it obtains the suitable conveying distance range of special new impellers of dredger pumps, and forms the impeller configuration scheme of 3,500 m3/h series cutter suction dredger with different conveying distance, which provides guidance for dredging engineering.
Damage Characteristics of Roadway Wall under the Impact of Gas Explosion
Authors: Jia Zhenzhen , Li Shujuan , Ye Qing , Ding Wenxue , Teng Yangzhou
Published: August 2022

In order to explore the damage process and characteristics of roadway wall under the impact of gas explosion, in this paper, the numerical model of gas explosion in roadway is established, and the explosion impact response of roadway wall and the stress change of gas explosion in roadway wall are analyzed. The results show that the impact produced by gas explosion is repeatedly reflected and superimposed on the wall, resulting in the high peak overpressure and duration growth in the explosion load process formed in the roadway. The shock wave propagation of gas explosion in wall is dynamic, and will produce tensile stress and compressive stress, causing damage to the interior of the wall. It will drive the wall structure of adjacent areas to move along the action direction of explosion load, resulting in the overall instability and damage of roadway wall structure. The research results can provide reference for gas explosion disaster prevention and explosion accident identification.
Optimization of Brayton Cycle CO2-Based Mixed Working Medium for Marine Low-Speed Diesel Engine Flue Gas Waste Heat Recovery
Authors: Xie Liangtao , Yang Jianguo
Published: August 2022

In this paper, the S-CO2 recompression Brayton cycle system of Marine Low-speed diesel engine flue gas waste heat recovery is built. By analyzing the physical characteristics of working medium and the law of the influence on the efficiency, five kinds of CO2-based mixed working medium are selected to optimize the CO2-based mixed working medium for Marine Low-speed diesel engine flue gas waste heat recovery from the aspects of total recovery energy, net recovery work and efficiency. The results show that the net recovery work of CO2-based mixed working medium supplemented with 20.11% propane increases by 17.02kW compared with that of pure CO2. The circulating efficiency of CO2 based mixed medium with 32.03% propane is increased by 5.42%.
Singularly Perturbed Solution of Non-Fourier Temperature Field with Mixed Boundary Value Dual-Phase Delay with Thermal Conductivity Jumps
Authors: Bao Liping , Jiang Yanan , Wu Liqun
Published: August 2022

Based on the properties of laminates, a class of nonlinear singularly perturbed mixture equations with discontinuous coefficients over bounded domains is constructed by using a dual-phase delayed heat conduction model. First, the singular perturbation expansion method is used, combined with the corresponding boundary conditions, the partial differential equation method and the Laplace transform method are used to obtain the external solution, the boundary layer, and the corner layer. Secondly, the time-varying temperature field at the discontinuity is obtained, which leads to the asymptotic expansion of the solution. Finally, the consistent validity of the asymptotic solution is obtained through residual estimation.
Numerical Study on Gas Blown in Tundish Side Walls
Authors: Zhou Feng , Huang Yonglin , Niu Hexuan , Geng Mengjiao , Wang Tianyang , Li Yuqian , Zhang Binshan , Chen Chao
Published: August 2022

The performance of gas blown in side walls of a single strand tundish is numerically simulated. Three cases are studied, i.e. tundish without gas blown, tundish with gas blown from the right side wall, and from the front wall. The vortex circulating flow is the main flow structure in tundish without gas blown. The gas blown from the right side wall of tundish will significantly change the flow field. The short-circuit flow that the tracer flow along the bottom of tundish to the outlet is becoming the main flow pattern. The RTD curve shows a rapid increase tendency. An anticlockwise flow near the top surface is formed. The mixing of tracer in the tundish is delayed and the dead volume fraction is increased when compared with the tundish without gas blown case. In contrast, the gas blown from the front wall of tundish will divide the tundish into two parts. The strong circulation flow in two parts is formed. Besides, the mixing of tracer is faster and the dead volume fraction is lower than that of the case without gas blown. This case may be an optimized gas blown technology in tundish.
Study on the Mechanism and Kinetics of O3/H2O2 Advanced Oxidation Reaction
Authors: Feng Leilei
Published: August 2022

With the advent of the era of Industry 4.0, the composition of industrial wastewater is complex and toxic, and at the same time, the country and people have higher and higher requirements for the environment, making water pollution prevention and control a lot of attention. The article systematically expounds the reaction mechanism of O3 single oxidation and O3/H2O2 advanced oxidation process, analyzes the superiority of O3/H2O2 process compared with O3 single oxidation, and experimentally explores the effect of O3/H2O2 process on DDNP production wastewater. The orthogonal experiment results show that the primary and secondary relationship of the influencing factors of O3/H2O2 process is pH>reaction time>O3 concentration>H2O2 dosage, the optimal process is pH=9, reaction time 30min, O3 concentration 8.64mg/L, H2O2 dosage 2ml/L, the effluent after treatment reaches the industrial discharge standard. By increasing the acidity and inhibiting the reaction of OH radicals under the condition of pH 3, the reaction order of the characteristic pollutants (nitrophenols) in the direct oxidation of O3 was determined to be first-order, and the rate constant was 0.148 L/moL·min.
Analysis of Pavement Performance for Nano-CaCO3/SBS Modified Asphalt Mixture
Authors: Sun Pei , Zhang Ke , Xiao Yun , Liang Zijun
Published: August 2022

In order to improve the technical properties of SBS modified asphalt, firstly, nano-CaCO3/SBS modified asphalt with nano-CaCO3 dosage of 1%, 2%, 3%, 4%, 5% and 6% were prepared, while the optimal nano-CaCO3 dosage was optimized by conventional laboratory experiments. Secondly, the pavement performance of SBS modified asphalt mixture and nano-CaCO3/SBS modified asphalt mixture was analyzed by relevant laboratory tests. The experimental results show that nano-CaCO3/SBS modified asphalt achieves the best performance when nano-CaCO3 dosage is 4%. Compared with SBS modified asphalt mixture, the high-temperature performance, water stability, indirect tensile strength and fatigue resistance of nano-CaCO3/SBS modified asphalt mixture are improved obviously, and the crack resistance at low-temperature is slightly decreased, but it still far meets the specification requirement. This indicates that it is possible to enhance the property of SBS modified asphalt and the performance of mixture by adding nano-CaCO3.
The Use of Slag and Red Mud for the Synthesis of a Slag-Based Cementitious Material
Authors: Quan Hong , Yu Huijuan , Lv Dongpeng , Li Yuancheng
Published: August 2022

A large amount of metallurgical slag storage occupies land and wastes a lot of resources. Therefore, this study uses slag and red mud (RM) as the main raw materials, sodium silicate, and sodium hydroxide (NaOH) as the composite alkaline activators, the slag-based cementitious materials were prepared by the secondary mixed grinding method. The mechanical properties of the cementitious materials were characterized and analyzed. The results show that when the ratio of slag to RM in the cementing material is 8:2, the strength increases initially and then decreases with the increase of the content of the alkaline activator. Meanwhile, the content of the alkaline activator is 10% (mass fraction), and the 28-day compressive strength of the sample is up to 67.8MPa, which meets the requirements of slag cement with a 42.5 strength grade.
Parametric Analysis of the Static Behavior for Stainless-Steel Beam-Column Connections
Authors: Qiao Xueliang , Wang Yuanqing , Jia Lianguang , Zhang Tianxiong , Qiao Guangyu
Published: August 2022

To study the influence of geometric parameters on flexural capacity and stiffness of beam-column connections using stain-steel S31608 and get the key influence parameters, on the basis of test data, using the finite element analysis software ABAQUS, parameter analysis on three main geometrical parameters of flexural capacity and stiffness of stain-steel beam-column connections was conducted. The analysis results show that when flange thickness of I-shaped bars increases, bearing capacity and initial stiffness of the joints increase with large amplitude; when slipping coefficient increases, bearing capacity and initial stiffness of the joints increase with small amplitude; when weld ac-cess hole changes, bearing capacity increases and initial stiffness increase with small amplitude, but can decrease stress concentrate phenomenon; when “Dog-bone” is used, the position of plastic hinge appearance will out-shift, but bearing capacity and initial stiffness decrease with large amplitude. Using the weld access hole of FEME350 and increasing the flange thickness of I-shaped bars is a good way to improve the static behavior of stain-steel beam-column connections.
Liquid-Infused Surfaces with Anti-Corrosion on Magnesium Alloy
Authors: Cai Qianqian , Xu Jinkai , Lian Zhongxu , Yu Huadong , Li Jian
Published: August 2022

The poor corrosion resistance of magnesium alloy has become the main reason restricting its application. In this paper, the layered double hydroxide (LDH) with good compactness was prepared on the surface of magnesium alloy by one-step hydrothermal method. The film thickness was 13 μm. The surface was injected with silicone oil to prepare the Liquid-infused surfaces (LIS). Electrochemical test studies show that the LIS has good corrosion resistance, and the lubricant and LDH on the surface can provide a double lasting physical barrier for magnesium alloy materials, effectively isolating chloride ions from corrosion to magnesium alloy substrates. In addition, the LIS is hydrophobic, which can reduce the contact area (CA) between the NaCl solution and the surface, and further improve the corrosion resistance of the magnesium alloy surface.
Effect and Mechanism of Ca2+ on the Corrosion of Hot-Rolled Strip in Turbid Ring Water Containing Cl− and SO2-
4
Authors: Xue J W , Yu W , Chen Y L
Published: August 2022

After the hot-rolled strip is cooled by laminar flow, Cl−, SO2-
4 and Ca2+ in turbid ring water will remain on the surface of the steel plate, which makes the steel plate corrode during storage in a humid environment. In order to clarify the effect and mechanism of residual Ca2+ on the corrosion of strip, simulations were carried out by setting different Ca2+ concentrations in solutions containing Cl− and SO2-
4 with different times of alternate immersion. Through the analyses of corrosion pit morphology, corrosion rate, electrochemical characteristics and corrosion products, it was found that the corrosion rate increased first and then decreased regardless of the Ca2+ concentration. When the Ca2+ concentration is 50~300 mg/L, the increase of Ca2+ concentration will increase the adsorption rate of the matrix and increase the corrosion pits. In addition, the corrosion rate decreases, the depth of corrosion pit becomes shallow and the polarization resistance increases due to the inhibition of the calcium salt layer, and the increase of Ca2+ concentration will enhance the inhibition of corrosion. When the Ca2+ concentration is 1000 mg/L, the denseness of the calcium salt layer is easily destroyed and the corrosion is intensified due to the large amount of adsorption of ions by the matrix.
Optimization of Ultrasonic-Assisted Aqueous Two-Phase Extraction of Flavonoids from Hawthorn Leaves Using Response Surface Methodology
Authors: Liang Junsong , Zhang Hao , Zhu Chuanhe
Published: August 2022

In this paper, using hawthorn leaves as raw materials, the effect of extracting total flavonoids from hawthorn leaves by aqueous two-phase system (ATPS) combined with ultrasonic assisted was studied. Through single factor test and response surface method Box-Behnken design (response surface method, BBD), according to the regression equation, the optimal process conditions were obtained as follows: the ratio of solid to liquid 1:37, ultrasonic time 40 min, ultrasonic power 360 w, ultrasonic temperature 65°C, and the yield of flavonoids was 2.869±0.0004%. This study shows that ultrasound combined with aqueous two-phase system (ATPS) is an effective method to extract total flavonoids from hawthorn leaves.
Influence of Abrasive Hardness on Chemical Mechanical Polishing of 304 Stainless Steel
Authors: Cao Xiaojun , Xue Mingpu , Qi Zhichao , Li Zhongtang , Su Jianxiu
Published: August 2022

In order to improve the quality in chemical mechanical polishing (CMP) of stainless steel and the material removal rate (MRR), 6 kinds of abrasives were used to do the CMP test of 304 stainless steel. In this paper, the 6 kinds of abrasives have different hardness. The experimental results show that, in the CMP process, the MRR increases with the increase of the abrasive hardness, the surface roughness decreases firstly and then raises with the increase of the abrasive hardness. This surface roughness reduces the lowest value when the chromium oxide (CrO) abrasive is used. With low-hardness copper oxide abrasives and magnesium oxide abrasives, it can only remove partial scratches on the surface during the polishing process and obtained low MRR and poor surface quality. Silica abrasives were easy to condense in the polishing slurry and the Gelation hindered the cutting action of abrasive, So resulting in low MRR and poor surface quality. The chromium oxide and white corundum, their hardness are close to the stainless steel, can remove the surface oxide layer of the sample while not produce the damage of the workpiece surface, so the surface quality was very well. Considering that chromium oxide contains Cr2+, it will pollute the environment. Therefore, in comprehensive consideration of the surface quality and MRR, take the white corundum as an abrasive in the CMP of 304 stainless steel.
Aerodynamic Characteristics of Supersonic Separator for Natural Gas Processing
Authors: Wang Chong , Li Yizhen , Zheng Mengqi , Wang Ke
Published: August 2022

Natural gas is a key energy source to achieve the carbon peaking and carbon neutrality goals in China. Dehydration and de-hydrocarbon process is crucial for pipeline transportation of natural gas since water and hydrocarbons in the natural gas would condense to cause corrosion and freeze-blockage in the pipeline. The supersonic separator is innovative low-temperature separation equipment characterized by a simpler equipment structure and higher refrigeration efficiency than the traditional device. In this paper, the numerical analysis is employed to predict the performance of the supersonic separator. The results show that this separator can reach an advanced level compared with others. The separator cannot start-up as the inlet-outlet pressure ratio is lower than1.29, and the minimum pressure ratio needed for normal work is 1.39. Under normal operating conditions, total pressure loss is about 25.4%, the minimum temperature is about 213K, and the mean rotation speed is about 170m/s.
Emergency Vehicle Intelligent Distribution System
Authors: Wang Yongxue , Xia Kaiwen , Yang Yanxiong , Xie Wu , Miao Qunfeng , Liu Tao
Published: August 2022

In this study, we developed a vehicle allocation model that can meet the requirements and cost best, the data related to the number of calls in each zone, and the variability required to respond to different types of calls. First, several indicators are extracted to quantify the advantages of station construction in each zone, and the hierarchical analysis method and TOPSIS are used to score each zone, and then select the stations that need to be built according to the score. Subsequently, according to the call requirements of each zone, its distance from the site, the amount of resources owned, etc, we develop a vehicle allocation model based on integer programming.
Complexity of the Operation Graphs on Cycle and Complete Graph
Authors: Wu Yalong , Ren Haizhen
Published: August 2022

The number of spanning trees (or complexity) of a graph can be used to measure the reliabilities of network and circuit design. Although many NP hard problems are related to the complexity of graphs, there are explicit formulas for the complexity of some specific graph classes. This paper mainly studies the explicit expression of the complexity of graphs obtained by graph operations. Through classical graph operations, we obtain some operation graphs generated by cycle and complete graph, and get the closed formulas for the complexity in these operation graphs. Compared with Daoud’s results, we obtain some interesting algebraic properties about the complexity of operation graphs.
Multi-step Time Series Forecasting Based on Informer-XGBoost-GA
Authors: Sun Chen , Chen Zhibin , Qin Yishuang , Wang Bebe
Published: August 2022

Multi-step prediction of time series has great significance in practical application. To improve the accurate prediction of multistep time series, time series prediction models have good long-time dependence and are able to analyze the correlation between information in time series. In this paper, a multi-step prediction model on the basis of Informer-XGBoost-GA was proposed, first establishing a combination of Informer and XGBoost, and then optimizing the weight of the combined model through GA. By comparing the experimental results, it can be seen that the proposed that the proposed prediction model significantly outperforms the comparison model and raise the accuracy of the prediction with advantage.
A State Transition Based Cache Side Channel Attack Model
Authors: Wang Chong , Wei Shuai
Published: August 2022

Over the last decades, the Cache Side Channel Attack (CSCA) seriously threatens the security of user information, which repeatedly highlights the security of cache. Even though the secure cache design can mitigate or defend against this attack, the high design period and tap-out cost reduce the development of the specific designs. Therefore, many researchers focus on proposing a secure cache model to analyse the CSCA and simplify the secure design. Nowadays, the cache model can be divided into 1) Indicator analysis model; 2) Cache verify model; 3) Cache abstract model. However, most of these models focus on the establishment phase of CSCA, regardless of the usage phase of CSCA. On the other hand, the granularity of the cache model is either the entire cache or a single cache line, which can’t describe the cache behaviour in CSCA clearly. To overcome these limitations, we proposed a novel cache model based on state transition and gave a formal specification of CSCA by this model in this work. Firstly, we summarize 11 basic states of the cache set and point to the target state in the process of CSCA. Then we describe the CSCA from three aspects: pre-attack cost, state transition cost, and detection accuracy, which gives a more comprehensive analysis of CSCA.
Multi-objective Optimization of Large-scale Multi-reservoir Flood Control Operation
Authors: Wang Quansen , Li Anqiang , Lu Chengwei
Published: August 2022

Joint operation of reservoir group is an important method for flood mitigation. Most of the existing flood control operation methods only focus on a single reservoir and a single object, which cannot take into account the coordination and complementarity of different reservoirs, and it is difficult to comprehensively consider the safety of multiple flood control objectives in the upstream and downstream of the basin. In this context, this paper proposed a multi-objective modeling and optimization method for flood control operation of large-scale reservoir groups based on different pre-set frameworks. 12 large reservoirs in the Yangtze River Basin were selected as a case. The results show that the proposed method can reasonably and effectively deal with the complex optimization problem of large-scale reservoir group operation scheme, and can further improve the intelligent level of multi-reservoir joint flood control operation.
The Multi-Objective Optimization of Headlamp Lighting System
Authors: Hsueh Bo-Ren , Lee Den-Hua , Chang Kuo-Chin , Chang Kow-Ming , Hsu Long , Wu Bo-Wen
Published: August 2022

When designing headlights using optical software LightTools, we found that the maximum illuminance and facula diameter of the initial headlamp lighting system design were less than 20000 lux (maximum illuminance) and 40mm (facula diameter), which did not meet the minimum performance requirements. However, if we increase the maximum illuminance value, the facula diameter value will become smaller and may not meet the minimum performance requirements. In order to obtain the best value of maximum illuminance and facula diameter at the same time, we used a multi-objective optimization method (combination of Taguchi method and robust multiple criterion optimization approach (RMCO)) to solve maximum illuminance and facula diameter optimization problem. It is effective and helpful increase the maximum illuminance and facula diameter of the headlamp lighting system (The maximum illuminance increased from 9580 lux to 22900 lux, the facula diameter increased from 40mm to 50mm). In this method, the concept of statistical analysis is used to obtain a set of diversified Pareto-optimal solutions. The set of diversified Pareto-optimal solutions can obtain for energy optimized design of headlamp lighting system. This study is the first attempt to use the RMCO method to optimize the multi-objective problem in a headlamp lighting system.
Wall panels using thermoelectric generators for sustainable cities and communities: a mini-review
Authors: Elgendi Mahmoud , Tamimi Jawaher AL , Alfalahi Aysha , Alkhoori Dana , Alshanqiti Mariam , Aladawi Ayesha
Published: August 2022

Traditional air conditioners consume a significant portion of energy and negatively affect households’ budgets. In addition, the compressor is noisy, and the leaked refrigerant may harm the environment. On the other hand, thermoelectric materials (TEM) are materials that can transform heat into electricity and vice versa. Therefore, TEM can be used as a thermoelectric cooler (TEC), so they will be an excellent alternative to traditional air conditioners because they are static and do not contain refrigerant. In addition, TEM can be used as a thermoelectric generator (TEG), thermoelectric heater (TEH), and thermoelectric dehumidifier (TED). PCM can work as a thermal reservoir so that absorbed or released energy occurs almost at a constant temperature. Therefore, PCM can act as a heat sink for TEG because PCM’s temperature depends on the type of PCM. During the day, the TEG-PCM unit as a wall panel generates electricity because heat transfers from the exterior to PCM. During the night, PCM’s latent heat transfers from PCM to the exterior, where the exterior temperature is cooler than the temperature of PCM. Therefore, TEG generates electricity. Also, TEC can cool PCM for cooling purposes. The thickness and kind of PCM significantly influence the system’s and PCM’s performance. Photovoltaic panels (PV) generate electricity from light. Therefore, PV can be integrated with TEG and PCM to increase the system’s total efficiency and augment the benefit. The present paper reviews the recent studies that adopt TEM for wall panels.
A comparative study on renewable energy policies between Japan and Malaysia
Authors: Tang YongHua , Choo Abby , Lau TeckChai , Chong WenTong , Wong KokHoe
Published: August 2022

The world relies heavily on fossil fuels for energy generation, thereby leading to global warming and regional climate change. Renewable energy (RE) is one of the realisable solutions to tackle the drastically increasing energy demand. As the global push for RE culminates within the coming years, energy policies will be the key driver in promoting RE deployment. Japan as a developed country aims to achieve a 36–38% share of RE in the energy mix by 2030, whilst Malaysia being a developing country has set a goal of achieving 31% RE mix by 2025. This paper presents a comparative study of RE policies between Japan and Malaysia, with the RE policies of both countries being analysed and presented chronologically. Moreover, the factors that contributed to the effectiveness of the policy and the measures that can be taken to overcome the shortcomings of the policies are elaborated. It is observed that both countries have been actively implementing a series of RE policies since the 21st century, especially Japan after the Fukushima nuclear disaster in 2011. Japan has shown an outstanding achievement where it achieved 20.8% of RE mix in 2020 while Malaysia is still far behind its target at approximately 2% in the same year. Hence, the Malaysian government should follow Japan’s footsteps in adopting and enforcing RE policies, and at the same time increase civil awareness regarding RE and stimulate participation from various stakeholders.
Numerical investigation of phase change heat transfer in a confined micro-space by lattice Boltzmann method
Authors: Qin Siyu , Ji Ruiyang , Tong Zixiang , Lu Zhao , Yang Chun , Meng Xiangzhao
Published: August 2022

Phase-change heat transfer has attracted wide attention in thermal management of electronic infrastructures, such as the data center and 5G base station antenna. It possesses the characteristics of high equivalent thermal conductivity, rapid heat diffusion and good temperature uniformity. However, the existing thermal solution to advanced high-performance devices becomes more challenging with high heat flux and small heat dissipation area. Current surface modification technology has been applied for enhancing phase-change means in energy-related fields. In this paper, the hybrid lattice Boltzmann (LB) method was utilized to explore vapor-liquid phase-change mechanism and its enhancement in a confined micro-space. Different modified surfaces’ effects on bubble growth behavior and interfacial phase-change heat transfer were respectively discussed. Based on the pseudopotential LB approach and energy equation, the boiling and condensation regimes were quantitatively evaluated with the heat transfer coefficient and transient heat flux. The numerical results indicated that the wettability possessed significant impacts on the primary characteristics of phase-change heat transfer. It was found that hydrophilic contact angle promoted the initial boiling, while hydrophobic one helped to facilitate drop-wise condensation. The hybrid surfaces possess the best performance for the boiling heat transfer enhancement. Both the modified hybrid and wettability gradient surfaces have positive contributions to the condensation heat transfer enhancement. This study is expected to provide a reference for improving phase-change heat transfer technology for sustainable energy applications.
Experimental and numerical investigation of a counter-flow hollow fiber membrane-based evaporative cooler
Authors: Yan W C , Thiam H S , Meng X Z , Liu Y L , Cui X
Published: August 2022

A counter-flow hollow fiber membrane-based evaporative cooler (HFMEC) was proposed. An experimental setup was developed to investigate the air handling performance of the HFMEC under various operating conditions. A numerical model was established and validated. The outlet air temperature predicted by the numerical model using free surface model showed a maximum deviation of 5% comparing with the experimental data. The model was further used to conduct a parametric analysis of the HFMEC. Six key parameters, including geometric specifications and operating conditions, were selected as factors for the sensitivity analysis. The cooling capacity and coefficient of performance (COP) were chosen as performance evaluation indicators. The simulation was performed with 27 cases for the orthogonal test. The range analysis revealed that the inlet air relative humidity and velocity, as well as packing fraction had significant impact on its cooling capacity and COP. Ranking the influence degree of key design parameters on performance evaluation indicators, this paper provides a convenient method to design and optimize the counter-flow HFMEC.
Effects of non-heating users in heating residential buildings on heat consumption
Authors: Gao X Y , Tang C L , Meng X Z , Luo X L , Yang X H , Yan C Q
Published: August 2022

Building heat consumption is affected by factors such as building characteristics, surrounding non-heating users, and outdoor temperature. Therefore, in order to achieve precise and efficient heating, it is of great importance to study the effects of building characteristics and the existence of non-heating users on the building heat consumption. This paper proposed two factors to evaluate the influences of the building characteristics and the non-heating users on heat consumption in a multi-storey heating residential building. Based on the heat consumption without non-heating adjacent users, the top-side users, top-middle users, middle-side users, middle-middle users, bottom-side users and bottom-middle users are identified as six types of typical-location users. Taking the heat consumption of middle-middle users as the benchmark, location factors (LFs) are introduced to consider the influence of building characteristics on the heat consumption of different typical-location users. For each typical-location user, non-heating user factors (NHFs) are introduced to consider the influences of different distributed non-heating adjacent users on the heat consumption of each typical-location user. The results show that, for low-temperature hot water floor radiant heating system, the impact of upstairs adjacent non-heating users is greater than that of same-floor adjacent non-heating users, and the impact of downstairs adjacent non-heating users is minimal. Besides, it can be considered the non-heating user factors vary slightly with the outdoor temperature when the outdoor temperature is below 0 °C. The results provide a guide for heating operation regulation of residential buildings with non-heating users.
Experimental Study of a Heat Pump Clothes Dryer Using Air-Conditioner’s Waste Heat
Authors: Lim Wan Lynn , Bahar Rubina
Published: August 2022

The urbanised living in Malaysia is progressing toward having clothes dryers as essential household equipment. The major problems with the commercially available clothes dryer are the high-power consumption and the possible damage to the environment. This study aims to mitigate these issues with an eco-friendly heat pump clothes dryer. The heat pump principle is derived based on the waste heat from the condenser side of the indoor air conditioner units. The study analyses the feasibility and potential of a heat pump clothes dryer replacing the available clothes drying methods. A small-scale clothes dryer was fabricated using low-cost materials, and the air properties were measured to assess the shift in the drying process. The fabricated prototype can dry faster by approximately 3 hours than outdoor drying at the balcony. This moderate drying is gentle on clothes compared to commercial high-temperature dryers. The study also indicates the impact of temperature settings of the air conditioner on the drying time of clothes. The heat pump dryer can dry up to 1.5 kg of clothes in 3 hours using a portable air conditioner with a power rating of 1.5 HP. It is found from a simple cost analysis that implementing the heat pump clothes dryer can significantly reduce the equipment and electricity cost of the household
Multiple-factor analysis of dehumidification performance and flow resistance for the cross-flow membrane module based on orthogonal test
Authors: Liu Y L , Su J C , Cui X , Yan W C , Li N , Jin L W
Published: August 2022

In this study, the multiple-factor analysis of dehumidification performance and flow resistance for the cross-flow membrane module was carried out based on the orthogonal test. Three operating and four structural parameters were selected as the independent variables for two test indicators, i.e., dehumidification rate (γ) and dehumidification account of per unit pressure drop (Δφ/Δp). The influence of seven factors on the test indicators was ranked by the single factor analysis of range. The results indicated that the inlet velocity of humid air, u
in, has the most important influence on γ and Δφ/Δp. Among the structural parameters of membrane module, the fiber length has the greatest impact on γ while that is the ratio of fiber pitch to fiber outer radius for Δφ/Δp. The empirical correlations of γ and Δφ/Δp were obtained by the regression analysis of simulated data, which help to predict the dehumidification performance and flow resistance of membrane systems from known structural parameters and operating conditions. According to plus or minus of the fitted exponents, the influences of seven factors on the two indexes are different. The better dehumidification performance and less flow resistance can be achieved by appropriately increasing w
in and l of the membrane module. This study is of guiding significance in the structure optimization of membrane modules.