bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Purification Technology of Silicon Carbide Crystal Growth Powder
Authors: Fan Guofeng , Li Tie , Zhao Lili , Zhang Shengtao
Published: November 2022

Silicon carbide (SiC) is a wide-bandgap (WBG) semiconductor material, and its preparation process has strict requirements on the purity of raw materials. A self-developed medium-frequency induction heating furnace was used to carry out powder heat treatment and purification experiments on SiC powder to improve the purity of the powder. Samples with 3.5N purity were analyzed using XRD and GDMS characterization methods. It was found that under conditions of high-temperature (2200 °C) and long-time (50 h) processing, the impurity removal effect was quite good, but the powder loss was as high as 53.42%. The powder loss during the low-temperature (less than 2050 °C) and short-time process was less than 1.5%, but the purification effect was not substantial. After a prolonged processing time, the purification effect of low-temperature heat treatment conditions was improved, but the powder loss was also increased to 30%. In contrast, segmented purification processing at a low temperature in the early stage and a high temperature in the later stage achieved a good purification effect. On the premise of maintaining the utilization rate of raw materials, a 5N-purity SiC source was successfully prepared. The test results show that the contents of free Si, free C and free oxygen impurities were reduced to less than 0.01%, and the contents of Al, B, Fe, Mg, Na, Ti and other impurities were less than 1.15 ppm, which is close to the ppb level.
Natural Zeolite Clinoptilolite Application in Wastewater Treatment: Methylene Blue, Zinc and Cadmium Abatement Tests and Kinetic Studies
Authors: Dosa Melodj , Grifasi Nadia , Galletti Camilla , Fino Debora , Piumetti Marco
Published: November 2022

In recent decades, several abatement techniques have been proposed for organic dyes and metal cations. In this scenario, adsorption is the most known and studied. Clinoptilolite was considered, since it is a zeolite with a relatively low cost (200–600 $ tons−1) compared to the most well-known adsorbent used in wastewater treatment. In this work, Clinoptilolite was used for the adsorption of Methylene Blue (MB) at three different concentrations, namely, 100, 200, and 250 ppm. Furthermore, the adsorption capacity of the natural zeolite was compared with that of Activated Charcoal (250 ppm of MB). The two adsorbents were characterized by complementary techniques, such as N2 physisorption at −196 °C, X-ray diffraction, and field emission scanning electron microscopy. During the adsorption tests, Clinoptilolite exhibited the best adsorption capacities at 100 ppm: the abatement reached 98% (t = 15 min). Both Clinoptilolite and Activated Charcoal, at 250 ppm, exhibited the same adsorption capacities, namely, 96%. Finally, at 250 ppm MB, the adsorption capacity of Clinoptilolite was analyzed with the copresence of Zn2+ and Cd2+ (10 ppm), and the adsorption capacities were compared with those of Activated Charcoal. The results showed that both adsorbents achieved 100% MB abatement (t = 40 min). However, cation adsorption reached a plateau after 120 min (Zn2+ = 86% and 57%; Cd2+ = 53% and 50%, for Activated Charcoal and Clinoptilolite, respectively) due to the preferential adsorption of MB molecules. Furthermore, kinetic studies were performed to fully investigate the adsorption mechanism. It was evidenced that the pseudo-second-order kinetic model is effective in describing the adsorption mechanism of both adsorbents, highlighting the chemical interaction between the adsorbent and adsorbate.
Aging Behavior and Precipitates Analysis of Wrought Al-Si-Mg Alloy
Authors: Liu Fang , Yu Fuxiao , Zhao Dazhi
Published: November 2022

Aging behavior of wrought Al-12.7Si-0.7 Mg alloy was investigated during isothermal aging at 180 °C. Two aging peaks were observed at 3 h and 8 h, respectively. To examine precipitate evolution during aging, the alloy’s microstructure in different aging states was investigated by regular and high-resolution transmission electron microscopy (TEM and HRTEM). The results revealed that the variation of mechanical properties is attributed to the combining effect of Si particles, the grain boundary, and the character of precipitates. The predominant precipitates’ type, size, and volume fraction vary as aging time increases.
Nanostructured Luminescent Gratings for Sensorics
Authors: Borodina Lyubov’ , Borisov Vladimir , Annas Kirill , Dubavik Aliaksei , Veniaminov Andrey , Orlova Anna
Published: November 2022

Two-dimensional holographic structures based on photopolymer compositions with luminescent nanoparticles, such as quantum dots, are promising candidates for multiresponsive luminescence sensors. However, their applicability may suffer from the incompatibility of the components, and hence aggregation of the nanoparticles. We showed that the replacement of an organic shell at the CdSe/ZnS quantum dots’ surface with monomer molecules of the photopolymerizable medium achieved full compatibility with the surrounding medium. The effect was demonstrated by luminescence spectroscopy, and steady-state and time-resolved luminescent laser scanning microscopy. We observed the complete spectral independence of local photoluminescence decay, thus proving the absence of even nanoscale aggregation, either in the liquid composition or in the nodes and antinodes of the grating. Therefore, nanostructured luminescent photopolymer gratings with monomer-covered quantum dots can act as hybrid diffractive–luminescent sensor elements.
Susceptibility of High-Manganese Steel to High-Temperature Cracking
Authors: Fojt-Dymara Gabriela , Opiela Marek , Borek Wojciech
Published: November 2022

Tests were carried out on two high-Mn steels: 27Mn-4Si-2Al-Nb with Nb microaddition and 24Mn-3Si-1.5Al-Nb-Ti with Nb and Ti microadditions. High-manganese austenitic steels, due to their good strength and plastic properties belong to the AHSS (Advanced High-Strength Steel) group and are used in the automotive industry. The main difficulties faced during the casting of the steel and hot working are hot cracks, which can appear in the surface of the ingot. Cracks on the edges of the sheet after hot rolling are the reason for cutting the edges of the sheet and increasing production costs and material losses. The main reason for the formation of hot cracks is the decrease in metal ductility in the high-temperature brittleness range (HTBR). The width of the HTBR depends on mechanical properties and microstructural factors, i.e., non-metallic inclusions or intermetallic phases at austenite grain boundaries. In this paper, a hot tensile test was performed. The research was performed on the GLEEBLE 3800 thermomechanical simulator. This test allows us to determine the width of the high-temperature brittleness range (HTBR), the Nil Strength Temperature (NST), the Nil Ductility Temperature (NDT), and the Ductility Recovery Temperature (DRT). Hot ductility was determined from the value of the reduction in area R(A). The obtained results make it possible to determine the temperature of the beginning of hot working from the tested high-Mn steels. Fractographic research enabled us to define mechanisms of hot cracking. It was found that hot cracks form as a result of disruptions in the liquid film on crystals’ boundaries.
Improved Hydrogen Generation of Al-H2O Reaction by BiOX (X = Halogen) and Influence Rule
Authors: Liao Lumin , Liu Jiaxi , Wang Tao , Xu Fen , Sun Lixian , Zhou Tianhao , Wu Jinfan , Guan Yanxun , Luo Yumei , Zou Yongjin , Chu Hailiang
Published: November 2022

In this work, three additives BiOX (BiOI, BiOBr, and BiOF) for Al-H2O reaction have been synthesized using chemical methods. SEM analysis shows that the structure of BiOF is nanoparticles, while BiOBr and BiOI have flower-like structures composed of nanosheets. Then, Al-BiOI, Al-BiOBr, and Al-BiOF composites have been prepared using the ball milling method. The effect of halogen ions on the performance of hydrogen generation from Al hydrolysis has been explored. The results indicate that the conversion yields of Al-BiOBr, Al-BiOI, and Al-BiOF for hydrogen generation are 96.3%, 95.3%, and 8.9%, respectively. In particular, the maximum hydrogen generation rate (MHGR) of Al-BiOI is as high as 3451.8 mL g−1 min−1, eight times higher than that of Al-BiOBr. Furthermore, the influence rule of BiOX (X = F, Cl, Br, and I) on Al-H2O reaction has been studied using density functional theory. The results illustrate that HI can be more easily adsorbed on the Al surface as compared with HF, HCl, and HBr. Meanwhile, the bond length between halogen ions and the Al atom increased in the order of F−, Cl−, Br−, and I−. Therefore, the dissociation of I− from the Al surface becomes easier and will expose more active sites to enhance the reaction activity of Al. In summary, the BiOI has the most favorable performance to Al-H2O reaction.
Effect of Fe Content on Microstructure and Properties of Laser Cladding Inconel 625 Alloy
Authors: Liu Weidong , Li Lei , Mi Guofa , Wang Jincai , Pan Yujia
Published: November 2022

Dilution rate is one of most important factors influencing the microstructure and performance of the laser cladding layer. In order to obtain a reasonable dilution rate in the laser cladding layer of Inconel 625 alloy, the laser cladding layers with different Fe content were prepared on the surface of 20# steel by the laser cladding technique. The influence of Fe content on the microstructure and performance of Inconel 625 alloy cladding layer was investigated. The results indicate that with the increase in Fe content in the alloy, the grain size of the cladding layer becomes coarser, the grain orientation difference increases first and then decreases, and the grain boundary angle decreases first and then increases. The hardness, high temperature wear resistance, and high temperature corrosion resistance gradually decreased. It is concluded that the dilution rate of Fe in laser cladding Inconel 625 alloy should be under 5 wt.%.
The Microwave Absorption in Composites with Finemet Alloy Particles and Carbon Nanotubes
Authors: Rinkevich Anatoly B. , Perov Dmitry V. , Kuznetsov Evgeny A. , Korkh Yulia V. , Klepikova Anna S. , Ryabkov Yury I.
Published: November 2022

The absorption of waves of the centimeter and millimeter wavebands in composites with Finemet alloy particles and carbon nanotubes has been studied. It has been established that ferromagnetic resonance and antiresonance are observed in such composites. A method is proposed for calculating the effective dynamic magnetic permeability of a composite containing both a random distribution of ferromagnetic particles and a part of the particles oriented in the same way. In the approximation of effective parameters, the dependences of the transmission and reflection coefficients of microwaves are calculated. It is shown that the theoretical calculation confirms the existence of resonant features of these dependences caused by ferromagnetic resonance and antiresonance. The theory based on the introduction of effective parameters satisfactorily describes the course of the field dependence of the coefficients and the presence of resonance features in these dependences. The frequency dependence of the complex permittivity of the composite is determined. The dependence of the complex magnetic permeability on the magnetic field for millimeter-wave frequencies is calculated.
Microbubbles Remove Listeria monocytogenes from the Surface of Stainless Steel, Cucumber, and Avocado
Authors: Chen Pengyu , Eifert Joseph , Jung Sunghwan , Strawn Laura K. , Li Haofu
Published: November 2022

Fresh produce may be contaminated by bacterial pathogens, including Listeria monocytogenes, during harvesting, packaging, or transporting. A low-intensity cavitation process with air being injected into water was studied to determine the microbubbles’ efficiency when detaching L. monocytogenes from stainless steel and the surface of fresh cucumber and avocado. Stainless steel coupons (1″ × 2″), cucumber, and avocado surfaces were inoculated with L. monocytogenes (LCDC strain). After 1, 24 or 48 h, loosely attached cells were washed off, and inoculated areas were targeted by microbubbles (~0.1–0.5 mm dia.) through a bubble diffuser (1.0 L air/min) for 1, 2, 5, or 10 min. For steel, L. monocytogenes (48 h drying) detachment peaked at 2.95 mean log reduction after 10 min of microbubbles when compared to a no-bubble treatment. After 48 h pathogen drying, cucumbers treated for 10 min showed a 1.78 mean log reduction of L. monocytogenes. For avocados, L. monocytogenes (24 h drying) detachment peaked at 1.65 log reduction after 10 min of microbubbles. Microbubble applications may be an effective, economical, and environmentally friendly way to remove L. monocytogenes, and possibly other bacterial pathogens, from food contact surfaces and the surfaces of whole, intact fresh produce.
Fault Tolerant Control of Quadrotor Based on Sensor Fault Diagnosis and Recovery Information
Authors: Huang Sunan , Liao Fang , Teo Rodney Swee Huat
Published: November 2022

Drones have been developed for more than two decades. They have become central to the functions of various civil aviation and military services. Commercial usage of drones continues to grow steadily. As the drones have been used widely in different areas, this raises a safety concern, i.e., all the multi-rotors have an increased risk of motor or sensor faults. This paper considers a fault-tolerant control (FTC) problem against the inertial motion unit (IMU) sensor fault. First, a neural network estimator is built for the purpose of fault diagnosis. Second, a fault detection scheme is designed by comparing the IMU reading with the estimator, where it uses a logic rule to monitor the IMU state. Third, if the IMU sensor is in faulty state, the Euler angle estimator with neural network built is used to recover the IMU information which is fed into the controller designed. Finally, simulation studies are given to illustrate the effectiveness of the proposed FTC.
Mathematical Modeling and Optimization of Platform Service Supply Chains: A Literature Review
Authors: Guo Xiaotong , He Yong
Published: November 2022

With the increasing importance of the platform service supply chain (PSSC) in creating economic value, academic research is paying more and more attention to it. The current literature’s research topics and problems cover broad areas. This review adopts bibliometric analysis and thematic analysis to review the related literature systematically and comprehensively. We divided the literature about PSSC into six groups according to the literature’s research topic and research question. Each literature’s research problem and research method are categorized and summarized. Our review results demonstrate that the supply chain’s members’ operational decisions and the supply chain’s coordination are two main types of research questions. Pricing decisions have received the most attention. In terms of the research method, game models are the most common method used in research to achieve the optimization of the PSSC.
Comparison of Genetic Operators for the Multiobjective Pickup and Delivery Problem
Authors: Little Connor , Choudhury Salimur , Hu Ting , Salomaa Kai
Published: November 2022

The pickup and delivery problem is a pertinent problem in our interconnected world. Being able to move goods and people efficiently can lead to decreases in costs, emissions, and time. In this work, we create a genetic algorithm to solve the multiobjective capacitated pickup and delivery problem, adapting commonly used benchmarks. The objective is to minimize total distance travelled and the number of vehicles utilized. Based on NSGA-II, we explore how different inter-route and intraroute mutations affect the final solution. We introduce 6 inter-route operations and 16 intraroute operations and calculate the hypervolume measured to directly compare their impact. We also introduce two different crossover operators that are specialized for this problem. Our methodology was able to find optimal results in 23% of the instances in the first benchmark and in most other instances, it was able to generate a Pareto front within at most one vehicle and +20% of the best-known distance. With multiple solutions, it allows users to choose the routes that best suit their needs.
The Inverse Transformation of L-Hermite Model and Its Application in Structural Reliability Analysis
Authors: Tong Ming-Na , Shen Fu-Qiang , Cui Chen-Xing
Published: November 2022

In probabilistic analysis, random variables with unknown distributions are often appeared when dealing with practical engineering problem. A Hermite normal transformation model has been proposed to conduct structural reliability assessment without the exclusion of random variables with unknown probability distributions. Recently, linear moments (L-moments) are widely used due to the advantages of stability and insensitivity. In this paper, the complete expressions of the inverse transformation of L-moments Hermite (L-Hermite) model have been proposed. The criteria are proposed to derive the complete inverse transformation of performance function and the complete expressions of the inverse transformation of L-Hermite model are formulated. Moreover, a first-order reliability method for structural reliability analysis based on the proposed inverse transformation of L-Hermite model is then developed using the first four L-moments of random variables. Through the numerical examples, the proposed method is found to be efficient for normal transformations since the results of the proposed L-Hermite are in close agreement with the results of Rosenblatt transformation. Additionally, the reliability index obtained by the proposed method using the first four L-moments of random variables provides a close result to the reliability index obtained by first-order reliability method with known probability density functions in structural reliability assessment.
Optimal Estimation of Large Functional and Longitudinal Data by Using Functional Linear Mixed Model
Authors: Ran Mengfei , Yang Yihe
Published: November 2022

The estimation of large functional and longitudinal data, which refers to the estimation of mean function, estimation of covariance function, and prediction of individual trajectory, is one of the most challenging problems in the field of high-dimensional statistics. Functional Principal Components Analysis (FPCA) and Functional Linear Mixed Model (FLMM) are two major statistical tools used to address the estimation of large functional and longitudinal data; however, the former suffers from a dramatically increasing computational burden while the latter does not have clear asymptotic properties. In this paper, we propose a computationally effective estimator of large functional and longitudinal data within the framework of FLMM, in which all the parameters can be automatically estimated. Under certain regularity assumptions, we prove that the mean function estimation and individual trajectory prediction reach the minimax lower bounds of all nonparametric estimations. Through numerous simulations and real data analysis, we show that our new estimator outperforms the traditional FPCA in terms of mean function estimation, individual trajectory prediction, variance estimation, covariance function estimation, and computational effectiveness.
Study of the Effect of Throttling on the Success of Starting a Line-Start Permanent Magnet Motor Driving a Centrifugal Fan
Authors: Paramonov Aleksey , Oshurbekov Safarbek , Kazakbaev Vadim , Prakht Vladimir , Dmitrievskii Vladimir
Published: November 2022

Direct-on-line synchronous motors are a good alternative to induction motors in fluid machinery drives due to their greater energy efficiency but have the significant disadvantage of limiting the maximum moment of inertia of the loading mechanism to ensure their successful and reliable start-up. This disadvantage is critical in centrifugal fans with a massive steel impeller. In this article, using a mathematical model, the dynamics of starting and synchronizing a permanent magnet synchronous motor fed directly from the mains as part of a fan drive are studied. The simulation results show the possibility of increasing the maximum moment of inertia of the load at the successful start-up of a direct-on-line synchronous motor by adjusting the hydraulic part of the fan pipeline by means of throttling. The conclusions of this paper can be used when selecting an electric motor to drive industrial fans and can contribute to wider use of energy-efficient synchronous motors with direct start-up from the mains.
Modelling, Optimization, and Experimental Studies of Refrigeration CO2 Ejectors: A Review
Authors: Zheng Lixing , Zhang Yiyan , Hao Lifen , Lian Haojie , Deng Jianqiang , Lu Wei
Published: November 2022

CO2 is regarded as an effective and environmentally friendly refrigerant. Using a CO2 ejector is a proven method for enhancing the effectiveness of a transcritical CO2 refrigerant system. However, the complex internal flow of a CO2 ejector, involving supersonic effects, phase change effects, metastable effects, and so on, makes it difficult to understand. In order to summarize the current state of the technology and knowledge gaps, this work provides a comprehensive literature review on CO2 ejectors. In the first part, mathematical modelling and simulation calculations of CO2 ejectors are presented, and an overview and classification of ejector models are given. In the second part, the structural optimization part of the ejector is described in detail, and the nozzle structure, the mixing chamber length, improvements to multi-jet systems, and the impact of these factors on the system performance are analyzed. In the third part, flow visualization is used to study the complex flow phenomenon, and the effect of the shock wave on the entrained rate of the ejector is discussed. Finally, the paper outlines the relationship between all ejector technologies, working fluids, and ejector performance and makes valid recommendations for further research and development of CO2 ejectors.
Echinochrome A Reverses Kidney Abnormality and Reduces Blood Pressure in a Rat Model of Preeclampsia
Authors: Cui Huixing , Liu Junxian , Vasileva Elena , Mishchenko Natalia , Fedoreyev Sergey , Stonik Valentin , Zhang Yinhua
Published: November 2022

We aimed to observe the effects of Echinochrome A (Ech A) on systemic changes using a rat model of preeclampsia. The results showed that an infusion of angiotensin II (Ang II) through an osmotic pump (1 μg/kg/min) on GD 8 increased systolic and diastolic blood pressures and reduced fetal weight and placental weight. The diameters of the glomeruli were expended and glomeruli capillaries were diminished. No change was observed in the heart and liver in the Ang II group, but epithelial structures were disrupted in the uterus. Ech A treatment on GD 14 (100 μg/μL) through the jugular vein reduced systolic and diastolic blood pressures and reversed glomerulus alterations, but the fetal or placental parameters were unaffected. Ech A only partly reversed the effect on the uterus. The mRNA expression of TNF–α was increased and IL–10 and VEGF were reduced in the uterus of the Ang II group, while Ech A restored these changes. A similar trend was observed in the kidney, liver, and heart of this group. Furthermore, Bcl–2 was reduced and Bcl–2/Bax ratios were significantly reduced in the kidney and heart of the Ang II group, while Ech A reversed these changes. We suggest that Ech A modulates inflammation and apoptosis in key systemic organs in Ang II-induced rat preeclampsia and preserves kidney and uterus structures and reduces blood pressure.
Membranes Based on PTMSP/PVTMS Blends for Membrane Contactor Applications
Authors: Kalmykov Denis , Balynin Alexey , Yushkin Alexey , Grushevenko Evgenia , Sokolov Stepan , Malakhov Alexander , Volkov Alexey , Bazhenov Stepan
Published: November 2022

In this work, perspective polymeric materials were developed for membrane contactor applications, e.g., for the dissolved oxygen removal from amine CO2 capture solvents. Several polymeric blends based on poly[1-trimethylsilyl-1-propyne] (PTMSP) and poly[vinyltrimethylsilane] (PVTMS) were studied. The gas and water vapor sorption and permeability coefficients for the PTMSP/PVTMS blend membranes at different PVTMS contents (0–100%) were obtained under temperatures of 30 and 60 °C for the first time. As the PVTMS content increases, the O2 and CO2 permeabilities decrease by 160 and 195 times at 30 °C, respectively. The fractional accessible volume of the polymer blends decreases accordingly. The transport of the CO2 capture solvent vapors through the PTMSP/PVTMS blend membranes were determined in thermo-pervaporation (TPV) mode using aqueous monoethanolamine (30%), N-methyldiethanolamine (40%), and 2-amino-2-methyl-1-propanol (30%) solutions as model amine solvents at 60 °C. The membranes demonstrated high pervaporation separation factors with respect to water, resulting in low amine losses. A joint analysis of the gas permeabilities and aqueous alkanolamine TPV data allowed us to conclude that the polymer blend composition of PTMSP/PVTMS 70/30 provides an optimal combination of a sufficiently high oxygen permeability and the pervaporation separation factor at a temperature of 60 °C.
Transmembrane Membrane Readers form a Novel Class of Proteins That Include Peripheral Phosphoinositide Recognition Domains and Viral Spikes
Authors: Overduin Michael , Tran Anh , Eekels Dominic , Overduin Finn , Kervin Troy
Published: November 2022

Membrane proteins are broadly classified as transmembrane (TM) or peripheral, with functions that pertain to only a single bilayer at a given time. Here, we explicate a class of proteins that contain both transmembrane and peripheral domains, which we dub transmembrane membrane readers (TMMRs). Their transmembrane and peripheral elements anchor them to one bilayer and reversibly attach them to another section of bilayer, respectively, positioning them to tether and fuse membranes while recognizing signals such as phosphoinositides (PIs) and modifying lipid chemistries in proximity to their transmembrane domains. Here, we analyze full-length models from AlphaFold2 and Rosetta, as well as structures from nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography, using the Membrane Optimal Docking Area (MODA) program to map their membrane-binding surfaces. Eukaryotic TMMRs include phospholipid-binding C1, C2, CRAL-TRIO, FYVE, GRAM, GTPase, MATH, PDZ, PH, PX, SMP, StART and WD domains within proteins including protrudin, sorting nexins and synaptotagmins. The spike proteins of SARS-CoV-2 as well as other viruses are also TMMRs, seeing as they are anchored into the viral membrane while mediating fusion with host cell membranes. As such, TMMRs have key roles in cell biology and membrane trafficking, and include drug targets for diseases such as COVID-19.
Kinetics of Bainite Transformation in Multiphase High Carbon Low-Silicon Steel with and without Pre-Existing Martensite
Authors: Babasafari Zeinab , Pan Alexey V. , Pahlevani Farshid , Moon Suk Chun , Du Toit Madeleine , Dippenaar Rian
Published: November 2022

In the present study, the isothermal decomposition of austenite to bainite in 1.0 wt% carbon, 0.21% silicon steel during the partitioning step of a quenching and partitioning (Q&P) heat treatment has been investigated in a dilatometer in the temperature range of 200 to 350 °C and compared to conventional austempering heat treatment. The bainite transformation was shortened by about 75% in the presence of pre-existing martensite (QP). The kinetics of bainite transformation is described by the well-known Avrami equation. The calculated parameter ‘n’ in the Avrami equation shows that bainite forms in the absence of pre-existing martensite (TT) at a constant nucleate rate, while in the presence of pre-existing martensite, nucleation is interface controlled. The overall bainite transformation activation energy, calculated by the Avrami equation, ranges from 64 to 110 kJ/mol. The outcomes of this investigation provide guidelines for the development of multiphase microstructures, including pre-existing martensite and bainite in high-carbon low-silicon steel, within an industrially acceptable time scale and mechanical performance.
Metallic Structures Based on Zinc Oxide Film for Enzyme Biorecognition
Authors: Iftimie Nicoleta , Steigmann Rozina , Faktorova Dagmar , Savin Adriana
Published: November 2022

Two structures (Ag/ZnO/ITI/glass: #1 sample and Ag/ZnO/SiO2/Si: #2 sample) are investigated, on the one hand, from the point of view of the formation of evanescent waves in the gratings of metal strips on the structures when the incident TEz wave in the radio frequency range is used. The simulation of the formation of evanescent waves at the edge of the Ag strips, with thicknesses in the range of micrometers, was carried out before the test in the subwavelength regime, with the help of a new improved transducer with metamaterial (MM) lenses. By simulation, a field snapshot was obtained in each sequence of geometry. The evanescent waves are emphasized in the plane XY, due to the scattering of the field on the edge of the strips. On the other hand, ZnO nanoparticles are investigated as a convenient high-efficiency biodetection material, where these structures were used as a biosensitive element to various enzymes (glucose, cholesterol, uric acid, and ascorbic acid). The obtained results demonstrate that the investigated structures based on ZnO nanostructures deposited on different supports are fast and sensitive for enzyme detection and can be successfully incorporated into a device as a biosensing element.
Soft Multifunctional Porous Sponge Sensor for Pressure and Strain Using Liquid Metal/Polydimethylsiloxane with Silver-Nanowire-Coated Composite
Authors: Kim Dong-Young , Nam Kun-Woo , Kang Byung-Ho , Park Sung-Hoon
Published: November 2022

Compression and tension sensors with a porous structure have attracted attention recently. Porous sponge sensors have the advantage of a wide deformation range owing to their structural characteristics. In this study, a porous sponge structure was prepared by absorbing polydimethylsiloxane (PDMS) into the matrix of porous commercial sugar cubes. A conductive network was formed by coating the outside of the sponge skeleton with silver nanowires (AgNWs), which have a high aspect ratio. In addition, a liquid metal (LM), which does not directly form an electrical network but changes from zero-dimensional to one-dimensional under an external force was introduced into this porous sponge structure. The effects of the LM on the sensor sensitivity to pressure and strain were analyzed by comparing the electrical resistance changes of PDMS/AgNW and LM/PDMS/AgNW sponge sensors under tension and pressure. This study shows that the use of a porous structure and an LM may be useful for future wearable sensor design.
Formation of a 3D Particle Array Actuated by Ultrasonic Traveling Waves in a Regular Polygon Resonator
Authors: Wan Fei , Xu Kai , Wang Hongcheng , Xu Haihao , Huang A’long , Bai Zihao , Zhang Linan , Wu Liqun
Published: November 2022

Acoustic radiation forces have been extensively studied regarding static particles, cell patterning, and dynamic transportation. Compared with standing wave manipulation, traveling wave manipulation can be more easily modulated in real time and has no matching requirement between the size of the resonant cavity and the sound frequency. In this work, we present an efficient, multi-layer microparticle pattern technique in a 3D polygon cavity with a traveling bulk acoustic wave. There are two types of excitation modes: the interval excitation mode (IEM) and the adjacent excitation mode (AEM). We conducted theoretical and simulation analyses, and our results show that both of these modes can form particle arrays in the resonant cavity, which is in accordance with the experimental results. The array spacings in the IEM and AEM were about 0.8 mm and 1.3 mm, respectively, while the acoustic frequency was 1MHz. Double-layer particle patterns were arrayed by a double in the resonant cavity. The spacing between the two layers was set at 3.0 mm. The line spacings were about 0.4 mm in both layers. The line width was 0.2 mm, which was larger than the single layer. The results show that ultrasonic traveling waves are a feasible method to manipulate particles and cells that form 3D patterns in particle–fluid flows.
Miniature Mesa Extension for a Planar Submicron AlGaN/GaN HEMT Gate Formation
Authors: Alathbah Moath , Elgaid Khaled
Published: November 2022

In this letter, a novel approach is presented to overcome issues in AlGaN/GaN high electron mobility transistors (HEMTs), such as metal discontinuity of the gate stemmed from conventional mesa isolation. This usually requires a careful mesa etch process to procure an anisotropic mesa-wall profile. An alternative technique is the use of ion implantation for device isolation instead of conventional mesa for a planar device formation. However, ion implantation is a costly process and not always easily accessible. In this work, the proposed method is to simply extend the mesa below the gate just enough to accommodate the gatefeed, thereby ensuring the entire gate is planar in structure up to the gatefeed. The newly developed device exhibited no compromise to the DC (direct current) and RF (radio frequency) performance. Conversely, it produced a planar gate configuration with an enhanced DC transconductance (approximately 20% increase is observed) and a lower gate leakage while the etch process is considerably simplified. Similarly, the RF transconductance of proposed device (device B) increased by 80% leading to considerable improvements in RF performance.
Detection of Helicobacter pylori from Extracted Teeth of a Patient with Idiopathic Thrombocytopenic Purpura
Authors: Hamada Masakazu , Nomura Ryota , Matayoshi Saaya , Ogaya Yuko , Kameyama Hiroyasu , Uzawa Narikazu , Nakano Kazuhiko
Published: November 2022

Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by isolated cryptogenic thrombocytopenia due to a transient or persistent reduction in platelet count. Many patients with ITP have shown improved platelet count after Helicobacter pylori eradication therapy. However, there have been no studies regarding H. pylori in the oral cavity of patients with ITP. Here, we describe a patient with ITP whose oral samples exhibited H. pylori. A 64-year-old woman with ITP came to our hospital with chief complaints that required oral surgery, including tooth extraction and cystectomy. Bacterial DNA from H. pylori was confirmed on the extracted tooth, but was not detected in the saliva taken at the time. Bacterial DNA from H. pylori was detected on the suture around the extraction socket, which was removed at 10 days post-operation. However, H. pylori DNA was not detected in other oral samples at 10 or 30 days post-operation. A urea breath test was carried out in the gastrointestinal clinic at 60 days post-operation, which revealed no presence of H. pylori in the gastrointestinal tract. These results suggest that teeth with severe bacterial infections may be a potential reservoir of H. pylori for patients with ITP.
Coriander (Coriandrum sativum L.) in Combination with Organic Amendments and Arbuscular Mycorrhizal Inoculation: An Efficient Option for the Phytomanagement of Trace Elements-Polluted Soils
Authors: Fontaine Joël , Duclercq Jérome , Facon Natacha , Dewaele Dorothée , Laruelle Frédéric , Tisserant Benoit , Lounès-Hadj Sahraoui Anissa
Published: November 2022

The cultivation of coriander (Coriandrum sativum L.) destined for essential oils production was recently presented as an innovative and economically viable alternative for the phytomanagement of trace elements (TE)-polluted soils. However, Cd accumulation in shoots has proven to be an obstacle in the valorization of the distillation residues and the development of these phytotechnologies. The present study aimed to evaluate the effect of arbuscular mycorrhizal fungus (Funneliformis mosseae) inoculation and organic amendment application on the soil TE bioavailability and plant uptake, as well as on the soil quality and health improvement. The application of compost and sewage sludge improved the growth of coriander and Cd and Zn immobilization in soil, resulting in reduced Cd plant uptake. A synergistic effect of arbuscular mycorrhizal fungi (AMF) inoculation and organic amendments was observed in the decrease in the extractable soil Cd and Zn concentrations, but not in the Cd plant uptake. Despite a significant decrease in Cd accumulation in shoots, coriander retained its accumulative phenotype, with a metal bioconcentration factor close to 1. Furthermore, both the vegetation and the organic amendments improved the soil quality and health by increasing its microbial biomass, as estimated by phospholipid fatty acids, soil enzyme activities (dehydrogenase, phosphatase, β-glucosidase, and cellubiosidase), and the bacterial metabolic function and diversity. The findings demonstrate the potential of C. sativum, particularly in combination with organic amendments and AMF inoculation, for the phytomanagement of TE-polluted soils and soil quality and health improvement.
Isolation and Identification of Arsenic Hyper-Tolerant Bacterium with Potential Plant Growth Promoting Properties from Soil
Authors: Mandal Debjani , Aghababaei Mina , Das Sadhan Kr , Majumder Santanu , Chatterjee Debashis , Basu Abhishek
Published: November 2022

The soil and groundwater of the Bhagobangola I block of Murshidabad district, West Bengal, India is severely arsenic-contaminated. A bacterium was isolated from the garden soil of the Mahishasthali village, which could tolerate 36.49 mM arsenic (III), 280.44 mM arsenic (V) and 63 mM chromium (III), which makes it arsenic (III and V) and chromium (III) hyper-tolerant bacterium. The growth pattern of this bacterium does not show much alteration in the presence of 10 mM arsenic (III) and chromium (III), emphasizing its resistance to these heavy metals. Scanning electron microscopic analysis depicted this bacterium to be rod-shaped with a size of ~1.45 µm. 16S rDNA sequencing, followed by subsequent phylogenetic analysis, established the identity of this bacterium as Microbacterium paraoxydans. This bacterium is capable of bioremediation of arsenic and showed 30.8% and 35.2% of bioremediation for 1mM and 22.6%, and 30.5% of bioremediation for 4mM arsenite, over a period of 24 and 48 h, respectively. Microbacterium paraoxydans also exhibits potential plant growth-promoting properties such as nitrogen fixation, phosphate solubilization, indole-3-acetic acid production and production of siderophores. Therefore, the heavy metal resistance, bioremediation potential and plant growth-promoting potential of the bacterium could be utilized not only for reduction in arsenic toxicity in soil and groundwater but also for plant growth promotion.
Prospectivity Mapping of Heavy Mineral Ore Deposits Based upon Machine-Learning Algorithms: Columbite-Tantalite Deposits in West- Central Côte d’Ivoire
Authors: Shaw Kassi , Goïta Kalifa , Germain Mickaël
Published: November 2022

This study aimed to model the prospectivity for placer deposits using geomorphic and landscape parameters. Within a geographic information system (GIS), spatial autocorrelation analysis of 3709 geochemical samples was used to identify prospective and non-prospective targets for columbite-tantalite (Nb-Ta) placer deposits of Hana-Lobo (H-L) Geological Complex (West- Central Côte d’Ivoire, West Africa). Based on mineralization system analysis, hydrologic, geomorphologic and landscape parameters were extracted at the locations of the identified targets. Supervised automatic classification approaches were applied, including Random Forest (RF), K-Nearest Neighbors (KNN) and Support Vector Machines (SVM) to find a prospectivity model complex enough to capture the nature of the data. Metrics such as cross-validation accuracy (CVA), Receiver Operating Characteristic (ROC) curves, Area Under Curve (AUC) values and F-score values were used to evaluate the performance and robustness of output models. Results of applying machine-learning algorithms demonstrated that predictions provided by the final RF and KNN models were very close (κ = 0.56 and CVA = 0.69; κ = 0.54 and CVA = 0.68, respectively) and those provided by the SVM models were slightly lower with κ = 0.46 and CVA = 0.63. Independent validation results confirmed the slightly higher performance of both KNN and RF prospectivity models, compared to final SVM. Sensitivity analyses of both KNN and RF prospectivity models for medium and high-grade Nb-Ta deposits show a prediction rate of up to 90%.
Efficient Hydrodynamic Modelling of Urban Stormwater Systems for Real-Time Applications
Authors: Baumann Henry , Ravn Nanna Høegh , Schaum Alexander
Published: November 2022

Urban water drainage systems represent complex networks with nonlinear dynamics and different types of interactions. This yields an involved modeling problem for which different off-line simulation approaches are available. Nevertheless, these approaches cannot be used for real-time simulations, i.e., running in parallel to weather now- and forecasts and enabling the monitoring and automatic control of urban water drainage systems. Alternative approaches, used commonly for automation purposes, involve parameterized linear delay systems, which can be used in real-time but lack the necessary level of detail, which, in particular, is required for adequate flood risk prognostics. Given this setup, in the present paper, an approach for the effective modeling of detailed water drainage systems for real-time applications implemented with the open-source Storm Water Management Model (SWMM) software is addressed and exemplified for a part of the water drainage system of the city of Flensburg in northern Germany. Additionally, a freely available early-warning system prototype is introduced and used to combine weather forcast information on a 2-h prediction horizon with the developed model and available measurements. This prototype is subsequently used for data assimilation using the ensemble Kalman filter (EnKF) for the considered area in Flensburg.
Nanoflower-like P-doped Nickel Oxide as a Catalytic Counter Electrode for Dye-Sensitized Solar Cells
Authors: Chen Yi-Lin , Huang Yi-June , Yeh Min-Hsin , Fan Miao-Syuan , Lin Cheng-Tai , Chang Ching-Cheng , Ramamurthy Vittal , Ho Kuo-Chuan
Published: November 2022

Flower-like phosphorus-doped nickel oxide (P-NiO) is proposed as a counter electrode (CE) for dye-sensitized solar cells (DSSCs). The flower-like nickel oxide essentially serves as the matrix for the CE, which is expected to promote a two-dimensional electron transport pathway. The phosphorus is intended to improve the catalytic ability by creating more active sites in the NiO for the catalysis of triiodide ions (I3−) to iodide ions (I−) on the surface of the CE. The P-NiO is controlled by a sequencing of precursor concentration, which allows the P-NiO to possess different features. The debris aggregation occurs in the P-NiO-1, while the P-NiO-0.75 leads to the incomplete flower-like nanosheets. The complete flower-like morphology can be observed in the P-NiO-0.5, P-NiO-0.25 and P-NiO-0.1 catalytic electrodes. The DSSC with the P-NiO-0.5 CE achieves a power conversion efficiency (η) of 9.05%, which is better than that of the DSSC using a Pt CE (η = 8.51%); it also performs better than that with the Pt CE, even under rear illumination and dim light conditions. The results indicate the promising potential of the P-NiO CE to replace the expensive Pt CE.
Comprehension of the Synergistic Effect between m&t-BiVO4/TiO2-NTAs Nano-Heterostructures and Oxygen Vacancy for Elevated Charge Transfer and Enhanced Photoelectrochemical Performances
Authors: Shao Zhufeng , Cheng Jianyong , Zhang Yonglong , Peng Yajing , Shi Libin , Zhong Min
Published: November 2022

Through the utilization of a facile procedure combined with anodization and hydrothermal synthesis, highly ordered alignment TiO2 nanotube arrays (TiO2-NTAs) were decorated with BiVO4 with distinctive crystallization phases of monoclinic scheelite (m-BiVO4) and tetragonal zircon (t-BiVO4), favorably constructing different molar ratios and concentrations of oxygen vacancies (Vo) for m&t-BiVO4/TiO2-NTAs heterostructured nanohybrids. Simultaneously, the m&t-BiVO4/TiO2-NTAs nanocomposites significantly promoted photoelectrochemical (PEC) activity, tested under UV–visible light irradiation, through photocurrent density testing and electrochemical impedance spectra, which were derived from the positive synergistic effect between nanohetero-interfaces and Vo defects induced energetic charge transfer (CT). In addition, a proposed self-consistent interfacial CT mechanism and a convincing quantitative dynamic process (i.e., rate constant of CT) for m&t-BiVO4/TiO2-NTAs nanoheterojunctions are supported by time-resolved photoluminescence and nanosecond time-resolved transient photoluminescence spectra, respectively. Based on the scheme, the m&t-BiVO4/TiO2-NTAs-10 nanohybrids exhibited a photodegradation rate of 97% toward degradation of methyl orange irradiated by UV–visible light, 1.14- and 1.04-fold that of m&t-BiVO4/TiO2-NTAs-5 and m&t-BiVO4/TiO2-NTAs-20, respectively. Furthermore, the m&t-BiVO4/TiO2-NTAs-10 nanohybrids showed excellent PEC biosensing performance with a detection limit of 2.6 μM and a sensitivity of 960 mA cm−2 M−1 for the detection of glutathione. Additionally, the gas-sensing performance of m&t-BiVO4/TiO2-NTAs-10 is distinctly superior to that of m&t-BiVO4/TiO2-NTAs-5 and m&t-BiVO4/TiO2-NTAs-20 in terms of sensitivity and response speed.
Causes and Consequences of Ordering and Dynamic Phases of Confined Vortex Rows in Superconducting Nanostripes
Authors: McNaughton Benjamin , Pinto Nicola , Perali Andrea , Milošević Milorad V.
Published: November 2022

Understanding the behaviour of vortices under nanoscale confinement in superconducting circuits is important for the development of superconducting electronics and quantum technologies. Using numerical simulations based on the Ginzburg–Landau theory for non-homogeneous superconductivity in the presence of magnetic fields, we detail how lateral confinement organises vortices in a long superconducting nanostripe, presenting a phase diagram of vortex configurations as a function of the stripe width and magnetic field. We discuss why the average vortex density is reduced and reveal that confinement influences vortex dynamics in the dissipative regime under sourced electrical current, mapping out transitions between asynchronous and synchronous vortex rows crossing the nanostripe as the current is varied. Synchronous crossings are of particular interest, since they cause single-mode modulations in the voltage drop along the stripe in a high (typically GHz to THz) frequency range.