bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Implementation of Indoor Visible Light Communication System based on High Order PAM
Authors: Wei Tongcheng , Zhang Bo , Lin Changyong
Published: May 2021

At present, most indoor visible light communication systems use switch keying, pulse position modulation and digital pulse interval modulation. These three modulation methods cannot effectively overcome the inter-symbol interference caused by the multipath effect in the visible light communication system. Compared with the above three modulation methods, high-order pulse amplitude modulation (Pulse Amplitude Modulation, PAM) transmits more bits in the same symbol, which can further improve the modulation efficiency and the communication rate of the system. At a given data rate, the inter-symbol interference caused by multipath effects can be reduced. Using TMS32C6748 floating-point DSP as the control chip of the optical communication system, an indoor visible light communication system based on high-order PAM is designed and implemented. The communication performance of the system is verified by building an experimental platform. The experimental results show that the communication system has the advantages of low bit error rate, high modulation efficiency, and high reliability, and meets the requirements of high-performance indoor visible light communication systems.
Effect of Threshold Switching Selectors on One-Selector One-Resistor Crossbar Arrays
Authors: Dai Yuehua , Wang Peng , Gao Jianhua , huaHuang Li , Ding Renjie , Yang Fei
Published: May 2021

In this paper, the influence of selector on the performance of 1S1R crossbar array memory is focused. First, a read-write circuit is designed based on the 1S1R cell model, which is a Verilog-A physical model built by our research team in the former work. Then, the parameters of selector (Vth, Vhold, RS-on, RS-off,NL) with different array sizes are calculated and analyzed. Different from the influence of selector on 1S1R cell, the read/write margin and read/write power consumption of the 1S1R crossbar array are impacted by selector significantly. Selectors with large Vth improve the write margin, but too large Vth reduce the read margin.The ON-resistance of the selector affects the read power consumption more than the OFF-resistance of the selector does, and the larger nonlinearity improves the overall performance of the crossbar array. Finally, this new 1S1R crossbar array memory is compared with 1R crossbar array memory and the result proved that the optimized memory can reduce the leakage current and power consumption to the large extent.
A FAST RFT METHOD BASED ON MULTIPLE FILTERING
Authors: Shen Mengmeng , He Feng , Dong Zhen , Gan Nan , Wu Manqing
Published: May 2021

A fast RFT method based on multiple filtering (MF-RFT) is proposed in this paper. The method on the basis of Radon Fourier Transform method, first of all, according to the target RCS and scenarios to determine or calculate the first decision threshold selection mode, the strong scattering points in the target echo are selected. Then, RFT and other traditional algorithms are used to achieve long-term coherent accumulation, which greatly reduces the calculation amount of the original method on the premise of ensuring the performance of parameter measurement and target detection. Then, the high efficiency and robustness of the proposed method in certain scenarios are proved by formula derivation and simulation.
Interactive Multi-Model Independent Joint Probabilistic Data Association Filtering Algorithm
Authors: Yu Xue , Xi-an Feng , Ni Zeng
Published: May 2021

Aiming at the problem of redundant calculation of the Interactive Multi-Model-Joint Probabilistic Data Association Filtering (IMM-JPDAF) algorithm, an Interactive Multi-Model Independent Joint Probabilistic Data Association Filtering algorithm is proposed. The algorithm uses model probabilities as priori information to reliably estimate the parameters of the maneuvering target motion model, and then uses them in the JPDA module, so that the JPDA can exist independently of the model filters. The simulation results show that the proposed algorithm can save about 20% of the calculation amount without reducing the accuracy of the target tracking, effectively reducing the redundancy.
Interface mechanical behavior of gold alloy wire bonding
Authors: Xie Shuang , Lin Pengrong , Yao Quanbin
Published: May 2021

The connection between the internal chip and external pins of the semiconductor package and the connection between the chip play an important role in establishing the electrical connection between the chip and the outside and ensuring the input/output between the chip and the outside. It is the key to the entire subsequent packaging process. Wire bonding has a dominant position in connection methods due to its simple process, low cost, and application of a variety of packaging forms. In high-reliability fields such as military and aerospace applications, bonding wires are usually used as chip interconnect materials. The bonding wires have good electrical conductivity, thermal conductivity, and oxidation resistance, but there are some reliability problems in bonding due to the production of Au-Al compounds. In this paper, Al element is used to modify the bonding alloy wire innovatively, the mechanical properties of Au-Al and Au-Pd system bonding points and the growth and evolution of IMC are studied, and the influence of Al and Pd elements on the reliability of bonding points is evaluated.
Research on Homogenization Treatment of Mg-8wt.% Sn-1.5 wt.% Al Alloy
Authors: Zhaoqian Sun , Yongjun Li , Kui Zhang , Xinggang Li , Minglong Ma , Guoliang Shi , Jiawei Yuan
Published: May 2021

The microstructure and morphology of Mg-8wt.%Sn-1.5wt.%Al alloy during homogenization were investigated by optical microscope (OM), scanning electron microscope (SEM), energy dispersive analysis (EDS) and HCT-3 comprehensive thermal analyzer. The results show that plenty of dendrite segregation arise in the as-cast alloy, and non-equilibrium eutectic phases distribute along the grain boundaries; at the same time, a large number of Sn and Al atoms segregated. The differential scanning calorimetry (DSC) curve shows that only one endothermic peak (549 °C) exists, which is caused by the redissolution of Mg2Sn phase; according to the homogenization empirical formula, 460 °C to 500 °C is the appropriate heat period. However, surface oxidation appears when treated at 500 °C; so atmosphere (Ar2) protect was used, after treating for 500 °C×48 h, ideal resolution effect has been achieved.
Failure analysis of sensor diaphragm cracking
Authors: Huan-ping Kong , De-lin Liu , Chang-kui Liu
Published: May 2021

The sensor diaphragm cracked during the test project. Through macro and micro morphology observation, metallographic examination and hardness test, the diaphragm failure properties and reasons were determined. The results showed that the failure nature of the faulted diaphragm was bidirectional bending fatigue cracking. 1# crack failure was related to the greater bending stress borne at the bottom of the outermost corrugation. 2# crack failure was related to the greater stress borne by the root at the boundary between the outermost corrugation and the outer edge, the appearance of grain boundaries caused by the pickling process promoted the initiation and propagation of 2# crack.
Region of Interest Coding Based on Convolutional Neural Network
Authors: Jinkai Yang , Guozhong Wang , Liangqi Zhu
Published: May 2021

The traditional region of interest coding method mainly uses low-level features to detect the Region of Interest (ROI). The ROI detected by it is poor in stability and is not easily interfered by noise. In this paper, ROI detection is performed on the image through a deep convolutional network to obtain a stable ROI based on the high-level feature extraction of the image, and then the discrete cosine transform (DCT) is performed on the image and divided into coding units. According to whether the coding unit is an ROI, To determine the quantization matrix used when encoding it. This article uses fine quantization for coding units that belong to ROI, and coarse quantization for non-ROI coding units. In this way, it can be ensured that the compression rate is greatly reduced without affecting the subjective perception of the image. Experiments show that the compression rate of this method can reach about 84%, and the weighted peak signal-to-noise ratio is improved by about 0. 99dB on average compared with JPEG encoding.
FlexRay bus data fault diagnosis based on Zynq
Authors: Peng Liu , Jia Li , Zefeng Yang
Published: May 2021

CAN bus and LIN bus are widely used as communication bus in automobile industry.As a new type of automobile bus, FlexRay bus, with CAN bus and LIN bus do not have many advantages. FlexRay bus bandwidth is not limited by protocol mechanisms,and it use the synchronization-based access methods. And because of its unique dual-channel data transfer mode, which is especially suitable for the current automotive wire control system, it replaces the mechanical and hydraulic working mode of traditional automobile. And the FlexRay data transmission rate is fast, it can quickly transmit data to the car’s electronic control unit. Zynq as an extensible platform combining ARM and FPGA,satisfying the programmability of the software,it also meets the programmability of hardware. Zynq chip functions can be divided into two working parts, A PS,another is PL. PS is the ARM part, mainly responsible for data storage and display module control and other functions; PL is the FPGA part, the main functions are data acquisition processing and time unification. Using based on Zynq data diagnosis FlexRay vehicle bus, can make data transmission more reliable and efficient, It can also effectively reduce the power consumption of the whole system.
Design of Compact Dual-band High-gain Planar Antenna for WLAN
Authors: Gou Zhong-Rong
Published: May 2021

A compact dual-band planar antenna with high gain for WLAN application is presented. The antenna fed by CPW is composed of T-type feed and double C-type meander line, which generate the higher and lower operation bands respectively. DGS structure in CPW ground broadens the bandwidths of high frequency. Through electromagnetic simulator software simulation and analysis, the overall size is 30×15.25×1.6mm. The simulation results show that the proposed antenna can operate in 2.35∼2.52GHz and 3.85∼6.14GHz, which cover the WLAN operating bands of IEEE 802.11n and 802.11a/b/g. The gain is 1.42dBi at 2.45GHz, and 4.42dBi at 5.2GHz, and 5.38dBi at 5.8GHz, respectively. The radiation patter of the antenna is omnidirectional and has higher gain.
Study on electronic structure and optical properties of doped ZnO system
Authors: Wei-rong Qiang , Xiao-mei Wang , Wei-qi Liu
Published: May 2021

In this paper, the electronic structure and photoelectric properties of P and Cu doped ZnO systems have been studied by Density functional theory method. The results show that the formation energies of ZnO-P-Cu, ZnO-P-2Cu, ZnO-P and ZnO-Cu systems decrease in turn Compared with the intrinsic ZnO system, the ZnO-P, ZnO-P-Cu, ZnO-P-2Cu and ZnO-Cu systems have higher activity, the band gap of ZnO-P and ZnO-P-2Cu systems is reduced, and the electron transition is easier. In the doped system, the peak of the dielectric function shifts to the left and increases, the absorption of the electron to the photon increases obviously, and the absorption spectrum appears red shift, from the calculated results, it can be concluded that P and Cu single-doped and co-doped ZnO have great influence on the electronic structure and optical properties of ZnO system, which provides a theoretical basis for further study of the influence of doping on the properties of ZnO.
Research on Thermal Characteristics of IGCT Based on Structure Function
Authors: Wang Weiyan , Zhang Xiaoling , Xie Xuesong , Huang Kunkun , Tan Yuhang
Published: May 2021

According to the principle of heat conduction during the operation of semiconductor devices, a GCT package model of IGCT devices is established. Perform transient simulation and use structure function analysis software for analysis. Based on the thermal resistance and heat capacity curve obtained by the structure function analysis method, the factors that may affect the thermal characteristics of the device are analyzed from the two angles of the thickness of the molybdenum disk and the thickness of the copper cathode. Thermal analysis of the 1μm micro-gap on the surface of the molybdenum disk and suggestions for improvement were put forward. The research results show that the structure function method is a non-destructive analysis method that can obtain the thermal resistance and heat capacity of each layer inside the device with high accuracy. The application of this method can analyze the internal microstructure changes of the device, and provide convenience for the research and evaluation of the thermal characteristics of the device.
A research on the spectral Bidirectional Reflectance Distribution Function measurement of tensile polyimide film rough surfaces
Authors: Mei Ming , Hailan Zhu , Yi Cai
Published: May 2021

The reflection distribution function is important for calculating the scatter distribution on material surface. In order to calculate the light scatter distribution of the tensile polyimide, it is necessary to investigate the relationship between the Bidirectional Reflectance Distribution Function (BRDF) of tensile polyimide film with its surface roughness and the incident light, and test the fitting function to evaluate the BRDF. The measurement spectrum is from 300nm to 750nm. The measurement results show that the BRDF of polyimide film are different with the tensile stress, and the reflectance intensity in the reflective direction decreases with the increase of the tensile stress, increases with the wavelength of the incident light. The reflectance intensity is associated with the roughness changing of polyimide surfaces for the tensile stress, as the roughness increases with the more stress, and the intensity increases in the none reflective direction. The fitting precision is up to 95% applying with the T-S model compared with the classical Phong model. The research data can be used to evaluate the reflective intensity of pharmaceutical packaging film, medical light barrier film, thermal insulation film and other film materials.
Identification and recovery path planning of Marine garbage patch based on Machine vision
Authors: Zhang Wenbin , Zhao Sheng
Published: May 2021

At present, the environmental problems in the water are becoming more and more prominent, and many teams are working on the research of the automation of garbage collection at sea. In order to a ready-made sea on the garbage recycling equipment automation, intelligent recognition for all white plastic and in identifying regional planning the path of the recycling of recycling equipment, aiming at different times during the day under the sea lighting situation, puts forward a visual processing and multi-step sea boundary identification method. After the image is processed by using two peak method normalized Canny boundary scan and other methods, the vertical and horizontal scanning and boundary recognition are carried out to obtain the closed Marine garbage main body area. Finally, Zigzag algorithm is used to carry out recovery path planning in the scanned area, and the results under different search radii are compared and analysed. The experimental results show that this method is applicable to a wide range of applications and has high accuracy and practicability, and the recognition results are satisfactory.
Study on Ultraviolet Photodetector modified by Au Nanoparticles on ZnO Nanowires
Authors: Fei Xiaomiao , Jiang Dayong , Wang Nan , Zhao Hongping , Xing Meijiao , Li Haoda
Published: May 2021

Zinc oxide (ZnO) is a direct wideband gap semiconductor material with a band gap of 3.37eV at room temperature. It can absorb ultraviolet light with a wavelength shorter than 385nm and is light blind to visible light. Using different growth methods or different growth conditions, the final prepared ZnO nanomaterials have different growth structures, which can be presented as nano dots, nanowires, nanoribbons, nano rings, nano tubes and other structures. In this paper, the ultraviolet (UV) photodetector (PD) of ZnO nanowires (NWs) was first prepared by wet etching and hydrothermal method. Then, gold (Au) nanoparticles (NPs) was used as metal nanoparticles with surface modification to characterize the performance of the PD, and the study of NPs modification on the performance of the detector was explored. After testing, the NPs modification improved the responsivity by about 12 times and the absorption was also improved to a certain extent. This paper provides a valuable reference for the material selection of UV PDs based on ZnO NWs surface modification.
Tunable Ultra-Broadband Terahertz Waveband Absorbers Based on Hybrid Gold-Graphene Metasurface
Authors: Xie Tong , Chen Dingbo , Xu Yanhong , Zhang Zhenrong , Yang Junbo
Published: May 2021

In this paper, we propose a tunable ultra-broadband terahertz absorber based on hybrid gold-graphene resonator to achieve an ultra-broadband, ultra-thin, and tunable metasurface, which has not only the high absorption rate of gold metamaterials but also the tunable properties of graphene metamaterials, compared with the traditional single gold-based and graphene-based methods. By simulating the response frequencies by the finite element method, we found that the absorber achieves a broadband 2.68-7.48 THz range (absorption>80%) absorbance with a relative bandwidth of 94.5%, where the center frequency is f
c=5.08THz. The physical mechanism of the absorber was analyzed using the electric field of the surface plasmon resonance, due to the design structure presents periodic geometric symmetry, the polarization angle and large angle incidence both present better advantages. The dynamic tuning of the metamaterial absorber is achieved by changing the Fermi energy level of graphene by adjusting the bias voltage to effectively control the metamaterial absorption intensity and resonant frequency. Our proposed absorber has important application prospects in sensing, optical communication, detection, and optical devices.
An algorithm for generating flame image data sets based on GAN
Authors: Qin Kui , Bu Leping , Zhou Yang , Yan Zhengjun , Wang Can , Wang Teng
Published: May 2021

In order to solve the problem of insufficient flame image data, this paper designs a flame image data sets generation algorithm based on generative adversarial network and studies the influence of different generator depth and training times on the flame generation effect. The effect of generative flame under different conditions was quantitatively evaluated by two indexes of Inception score and PSNR. The simulation results show that when the generator is 9 layers and training is 80 times, the Inception score is 2.06 and PSNR is 13.18. The effect of generative flame image is better at this time. Therefore, this generative adversarial network model can better realize the purpose of generating the flame image data sets.
Research on Fatigue Phenomenon and Internal Mechanism of HfZrO2 Ferroelectric Thin Film Memory
Authors: Liu Jie , Zhu Hui , Li Rui , Wang Si , Zhang Zhirang , Xie Na , Huang Zeng
Published: May 2021

The fatigue effect of the HfZrO2 thin film sample plays a vital role in its application in the semiconductor field. This article explores the fatigue mechanism inside the thin film sample by studying the effect of various experimental conditions on the ferroelectric properties of the sample, and analyzes the experimental results. Then we study the experimental results to clarify the changes in the micro-physical mechanism inside the sample.Combined with macro-theory and micro-examination, we observe that experimental conditions such as the pulse width of the applied pulse will affect the change of the sample’s remnant polarization values during the fatigue cycle. Finally, we try to optimize these conditions to achieve stable remanent polarization. This paper further clarifies the fatigue mechanism of the sample through the mathematical analysis of experimental data and the comparison of existing theories, and points out the direction for optimizing the application of the device.
The molecular beam epitaxy growth of InGaAsSb/AlGaAsSb quantum well on GaAs substrate with emission wavelength of∼ 2μm
Authors: Jia Huimin , Tang Jilong , Shen Lin , Kang Yubin , Hou Xiaobing , Ma Xiaohui , Wei Zhipeng
Published: May 2021

InGaAsSb layers and InGaAsSb/AlGaAsSb quantum wells nearly lattice-matched to GaSb were grown by solid-source molecular beam epitaxy on GaAs substrates. As2 and Sb2 sources produce by valved crackers were used for the growth of quaternary InGaAsSb layer and InGaAsSb/AlGaAsSb quantum well structure, which greatly facilitated the lattice-matched to GaSb, as characterized by X-ray diffraction. In order to adjust the composition of indium in InGaAsSb, the indium flux was changed by different indium source temperature under the condition of fixed growth temperature and gallium flux, and InGaAsSb with emission wavelength of 2018 nm at room temperature was grown. By using this growth parameter, the InGaAsSb/AlGaAsSb quantum well structure with 20 nm well layer and emission wavelength of 1966 nm at room temperature was then grown. X-ray diffraction and photoluminescence results indicate that ∼2 μm InGaAsSb/AlGaAsSb quantum well structure on GaAs with better crystal and optical properties had been prepared successfully.
An X-ray detector based on a Pt-MgZnO-Pt structure
Authors: Guo Xiaocheng , Wang Haoning , Long Hao , Yang Jing
Published: May 2021

Direct-conversion X-ray detectors made of wide-bandgap semiconductors have many advantages and important applications. In this study, a direct-conversion X-ray detector based on Pt-MgZnO-Pt structure was fabricated by radio frequency magnetron sputtering. The X-ray detection characteristics of the device were studied. The optimized device with a structure of Pt-MgZnO-Pt exhibited a responsivity of 72.6 nC Gyair
–1 cm–2, response time of ∼0.1 s (rise)/∼0.4 s (fall), and a high SNR of 206 at a bias of 30 V under a dose rate of 100 mGyair/s. The experimental results demonstrate the good application prospects of the wide-bandgap MgZnO-based X-ray detectors.
Fracture analysis of a Ni-based single crystal superalloy
Authors: Zhang Jiawei , Wei Wencong , Song Jinxia , Xiao Chengbo , Liu Furong
Published: May 2021

Based on the tensile stress-dominated low cycle fatigue (LCF) tests at 760°C, the fracture morphology of a second-generation Ni-based single crystal superalloy (SC) was studied in this paper. It was found that under LCF loading the specimen cracked with one fatigue source. The angle of fatigue bands in crack propagation region was related to the secondary orientation deviation from crystal orientation [100]. In addition, evidence showed that the specimens fractured along the slip surface of {111}<110> octahedral slip systems.
Research on the Development Strategy of the Internet of Vehicles
Authors: Gong Yuanjia , Feng Hailiang , Zhang Chong
Published: May 2021

Firstly, this paper discusses several challenges faced by the existing single-vehicle intelligent driving and intense demand for connecting, then proposes the system architecture of the Internet of Vehicles from the perspective of communication capability and application support. Finally, the paper puts forward development strategies for the autonomous driving, forming a global wide recognition.
A Data Transmission System for Sewage Treatment in Oil Refinery Based on LoRa
Authors: Tan Yuhang , Zhang Xiaoling , Xie Xuesong , Huang Kunkun , Wang Weiyan
Published: May 2021

This paper designs a wireless data transmission system based on LoRa technology in view of the safety requirements of the upgrade of the oil refinery sewage treatment system. On the basis of protecting the data flow of the previous system, the measurement data of each sensor is collected and sent to the PLC in a wireless manner. By the reasonable circuit structure design and the wireless transmission mode choice, this system has high explosion-proof performance, high safety, and has the advantages of good real-time performance, high maintainability, and easy expansion.
InGaAs/InAlAs quantum well structures grown on GaAs (001) substrate by molecular beam epitaxy
Authors: Xiaobing Hou , Yubin Kang , Jilong Tang , Xiaohua Wang , Zhipeng Wei
Published: May 2021

A 100 periods In0.53Ga0.47As/In0.52Al0.48As quantum well structure was grown by molecular beam epitaxy (MBE) on GaAs (001) substrate. The XRD results of ternary alloy InGaAs and InAlAs films show that the indium component is similar to the designed structure. In addition, the XRD results show that the In0.53Ga0.47As/In0.52Al0.48As multi-quantum well structure is consistent with the designed structure. The PL spectrum of In0.52Ga0.48As/In0.53Al0.47As quantum well structures is ∼1470 nm at room temperature.
Supply chain effects of China’s fast growing marine economy on greenhouse gas emissions
Authors: Li Man , Feng Kuishuang , Zheng Heran , Pan Chen , Meng Jing , Li Jiashuo , Guan Dabo , Li Yuan
Published: May 2021

The marine economic activities has become a vital economic driving force for development of China’s economy. However, the trajectory of greenhouse gas (i.e. GHG) emissions associated the fast growing marine economy and its role in emission mitigation remain unclear. Through compiling high-resolution and time-series environmental input–output tables for 2002, 2007, 2012 and 2017, this study quantify development of 13 key marine industries in driving national economic development and its supply chains, and assesses the direct and indirect contributions of marine industries to the national economy and GHGs emissions. Our results show that the total emissions of marine economy increased by 2.3 times from 2002 to 2017, and the share of that in national total emissions increased by 43.3%. The economic output of marine economy may lead to up to 1.8 times of the total economic output in the upstream industries, while the indirect emissions of major marine economy embodied in the upstream supply chains is on average 3.5 times of direct emissions from marine industries. Our findings highlight the necessity of considering total supply chain GHGs emissions associated with the fast growing marine economy to better achieve China’s climate mitigation targets.
A Study on Mechanical and Durability Properties of Structural Concrete using Pumice and Sintered fly ash Aggregates
Authors: Yaswitha Reddy M. Sai , Visweswara Rao V.K. , Srinivasula Reddy M.
Published: May 2021

Lightweight aggregates has low density, high permeability than the conventional coarse aggregate. Most commonly available lightweight aggregate (LWA) are Pumice aggregate (PA), which is a natural aggregate, sintered fly ash aggregate (SFA), which is made by sintered processing the fly ash obtained as a by-product of coal based Thermal power plants. Among the many artificial aggregates, SFA is used as a replacement to coarse aggregate to produce lightweight aggregate concrete. This paper presents an experimental study of structural lightweight aggregate concrete (SLWAC) using combination of PA and SFA as a partial replacement for coarse aggregates. In this, the mechanical and durability properties of SLWAC using different percentages i.e., 25%, 50%, 75% and 100% of PA and the rest natural coarse aggregate, fully replacement of coarse aggregate with 50% PA and 50% SFA, are evaluated by conducting comprehensive series of tests on strength and permeability parameters. The test results showed better strength and adequate density, at coarse aggregate replacement with 50% PA and 50% SFA, to be accepted as SLWAC as per ASTM standards. When the coarse aggregate is completely replaced by pumice aggregate alone, the strength achieved is poor and is suitable for non-structural members. In this study, the mixes are designed for M25 grade concrete and the results are then compared with M25 grade of conventional concrete (CC).
The Role of Boundary Layer Theory in Soccer Ball Dynamics
Authors: Kapothanillath Abhijith Namboodiri , Pradeep Sidharth , Sathishkumar Shriram , Balaji K
Published: May 2021

The boundary layer theory plays a major role in the development of fluid mechanics applications especially in the sports ball dynamics. Whenever an object travels through the air, it experiences aerodynamic forces acting on it. Sport balls, uses these forces to deviate from its expected path of flight. Thus, creating an advantage which can be exploited by the playing members to improve their skills. The present study focuses on numerical simulation of aerodynamic flow over a soccer ball and estimated the drag coefficient. In order to a get more precise results, the effect of gravity is included to study the dynamics of flow. The variation of drag coefficient is plotted as a function of Reynolds number and wind speed. The computational result had a good agreement with existing empirical data.
Design and Analysis of a Self-balancing Bicycle Model
Authors: Nitheesh kumar G , Navneeth S , Suraj A , Sreedharan Pramod
Published: May 2021

This paper discusses the design and analysis of a self-balancing bicycle model. The objective was to develop an efficient design that can be fabricated in the future. The different methods of balancing a bicycle were studied to develop an optimal design. Solidworks 17 and Ansys 18 have been used for modeling, simulation, and analysis of the structure. The use of a Control Moment Gyroscope (CMG) to balance the bicycle model was studied and the results show that the effect of precession increases with an increase in rpm and the weight of the flywheel. Thus, a bicycle model actuated with CMG is far more stable and less prone to accidental tilts and toppling than one without. The studied data can be used for future research.
Product design and development of a reading aid for the visually impaired
Authors: Gopinath Ajith , Babu Shibin , Claudius Allen Bob , Ismail Shaik Mohammed , Sandeep O.S
Published: May 2021

One of the main hurdles for the blind are to read, easily and there by learn and graduate. Various researches are happening to reduce the effort required for the blind to read in terms of aids which can speak out the written data. The current research targets to design and fabricate a reading aid for the visually impaired. This device will help them to identify the text written in any book or page by scanning the text and speaking it out to them with the help of a mobile application called KNFB reader which helps to read anything to blind or dyslexic people. This project utilizes the fact that majority of the people use smartphones, which can be used for the advantage of the blind people. Based on a survey conducted among the blind people with the help of an NGO Anuprayas all the criteria for the design of reading aid, in the current project were selected. Four sample designs were prepared after taking the criteria for reading aid into consideration. Forced Decision matrix (FD) analysis and Decision alternative ratio System (DARE) analysis, which are tools to rank the properties based on the priority, were conducted to identify the most influential parameter for the design. The parameters were ranked based on these analyses. The ergonomics, cost and durability were the most important properties desired in the product. This product can be deployed for the effective utilization by public at railway stations, bus stations, libraries etc. This will enable the blind to be selfindependent and have the information available for them whenever they need it.
Enhanced removal of ultrafine particles from kerosene combustion using a dielectric barrier discharge reactor packed with porous alumina balls
Authors: LI Jing , LU Haiquan , WANG Qi , LI Guojian , YAO Shuiliang , WU Zuliang
Published: May 2021

Ultrafine particles (UFPs) are harmful to human beings, and their effective removal from the environment is an urgent necessity. In this study, a dielectric barrier discharge (DBD) reactor packed with porous alumina (PA) balls driven by a pulse power supply was developed to remove the UFPs (ranging from 20 to 100 nm) from the exhaust gases of kerosene combustion. Five types of DBD reactors were established to evaluate the effect of plasma catalysis on the removal efficiency of UFPs. The influences of gas flow rate, peak voltage and pulse frequency of different reactors on UFPs removal were investigated. It was found that a high total UFP removal of 91.4% can be achieved in the DBD reactor entirely packed with PA balls. The results can be attributed to the enhanced charge effect of the UFPs with PA balls in the discharge space. The UFP removals by diffusion deposition and electrostatic attraction were further calculated, indicating that particle charging is vital to achieve high removal efficiency for UFPs.
Longitudinal Associations Between Changes in Cigarette Smoking and Alcohol Use, Eating Behavior, Perceived Stress, and Self-Rated Health in a Cohort of Low-Income Black Adults
Authors: Bloom Erika Litvin , Bogart Andy , Dubowitz Tamara , Collins Rebecca L , Ghosh-Dastidar Bonnie , Gary-Webb Tiffany L , Troxel Wendy
Published: May 2021

Background

Black adults in the U.S. experience significant health disparities related to tobacco use and obesity. Conducting observational studies of the associations between smoking and other health behaviors and indicators among Black adults may contribute to the development of tailored interventions.

Purpose

We examined associations between change in cigarette smoking and alcohol use, body mass index, eating behavior, perceived stress, and self-rated health in a cohort of Black adults who resided in low-income urban neighborhoods and participated in an ongoing longitudinal study.

Methods

Interviews were conducted in 2011, 2014, and 2018; participants (N = 904) provided at least two waves of data. We fit linear and logistic mixed-effects models to evaluate how changes in smoking status from the previous wave to the subsequent wave were related to each outcome at that subsequent wave.

Results

Compared to repeated smoking (smoking at previous and subsequent wave), repeated nonsmoking (nonsmoking at previous and subsequent wave) was associated with greater likelihood of recent dieting (OR = 1.59, 95% CI [1.13, 2.23], p = .007) and future intention (OR = 2.19, 95% CI [1.61, 2.98], p < .001) and self-efficacy (OR = 1.64, 95% CI [1.21, 2.23], p = .002) to eat low calorie foods, and greater odds of excellent or very good self-rated health (OR = 2.47, 95% CI [1.53, 3.99], p < .001). Transitioning from smoking to nonsmoking was associated with greater self-efficacy to eat low calorie foods (OR = 1.89, 95% CI [1.1, 3.26], p = .021), and lower perceived stress (β = −0.69, 95% CI [−1.34, −0.05], p = .036).

Conclusions

We found significant longitudinal associations between smoking behavior and eating behavior, perceived stress, and self-rated health. These findings have implications for the development of multiple behavior change programs and community-level interventions and policies.
Effects of gait adaptability training on falls and fall-related fractures in older adults: a systematic review and meta-analysis
Authors: Nørgaard Jens Eg , Jorgensen Martin Gronbech , Ryg Jesper , Andreasen Jane , Danielsen Mathias Brix , Steiner Daniel Kjærgaard , Andersen Stig
Published: May 2021

Objective

falls among older adults are common and can have devastating consequences. A novel task-specific exercise modality, gait adaptability training (GAT), has shown promising preventive effects. This systematic review and meta-analysis synthesise the evidence regarding GATs effect on falls and fall-related fractures in community-dwelling older adults.

Methods

electronic databases (PubMed, EMBASE, CINAHL, CENTRAL) were systematically searched from inception to 18 June 2020. Additional sources include searches of trial registrations, manual screening of reference lists and requests to experts. We included randomised controlled trials (RCTs) evaluating the effect of GAT on falls with at least 6-month follow-up among community-dwelling people aged 60+ years. Two reviewers independently screened studies against eligibility criteria, extracted relevant information and appraised studies for bias. Random-effects meta-analytic models were employed to pool effect estimates.

Results

eleven studies with 1,131 participants were included. A meta-analysis in which an outlier study was excluded showed that GAT reduces fall rates by 42% (incidence rate ratio 0.58, 95% confidence interval [CI] 0.39–0.81, I2 = 0.00%; moderate certainty; seven RCTs). Moreover, proportion with fall-related fractures and proportion of fallers was reduced by 81% (risk ratio [RR] 0.19, 95% CI 0.06–0.56, I2 = 0.00%; very low certainty; two RCTs) and 43% (RR 0.57, 95% CI 0.4–to 0.8, I2 = 47.08%; low certainty; 11 RCTs), respectively.

Conclusions

our results show that GAT significantly reduces the number of falls and prevents fall-related fractures in older community dwellers. GAT is a promising and feasible exercise modality; however, studies of high quality should be conducted to support a robust conclusion.

Protocol registration

PROSPERO; CRD42020191051.
Multivariate Optimization of an SPME Technique for GC–MS Analysis of Urinary BTX
Authors: Ribeiro-Júnior Flávio Henrique , Silveira Alberto Thalison , de Faria Henrique Dipe , dos Reis Giusto Luana Aparecida , Pissetti Fábio Luiz , Martins Isarita
Published: May 2021

Volatile organic compounds (VOCs), such as benzene, toluene and xylenes (BTX), are recognized as environmental contaminants due to their acute and chronic toxic effects, and toluene is a substance contained in products used in inhalants. In this way, methods able to determine these substances in non-invasive matrices offer great applicability for assessing acute exposure. In this study, a functionalized polymer, chloropropyltrimethoxysilane/polydimethylsiloxane, was evaluated as a potential material to be used in solid-phase microextraction for the quantification of BTX in urine by gas chromatography coupled to mass spectrometry (GC–MS). The method optimization was performed by using fractional factorial planning 2 (4–1) and the Doehlert’s experiment. Desorption time and salinity were the most important factors that impact the sensitivity of the method. Spectroscopic and thermogravimetric characterization demonstrated the functionalization of the material and its thermal stability up to 390°C. This allowed it to be used for ~60 analytical cycles without loss of efficiency. The proposed method demonstrated a satisfactory analytical performance to determine the VOCs studied. The protocol agrees with the principles of green analytical chemistry since the procedure reduced the reagents consumed and wastes generated. It represents a promising tool for acute exposure assessment to BTX since urine tests demonstrated its applicability.
Increased Peripheral Blood Neutrophil Activation Phenotypes and Neutrophil Extracellular Trap Formation in Critically Ill Coronavirus Disease 2019 (COVID-19) Patients: A Case Series and Review of the Literature
Authors: Masso-Silva Jorge A , Moshensky Alexander , Lam Michael T Y , Odish Mazen F , Patel Arjun , Xu Le , Hansen Emily , Trescott Samantha , Nguyen Celina , Kim Roy , Perofsky Katherine , Perera Samantha , Ma Lauren , Pham Josephine , Rolfsen Mark , Olay Jarod , Shin John , Dan Jennifer M , Abbott Robert K , Ramirez Sydney , Alexander Thomas H , Lin Grace Y , Fuentes Ana Lucia , Advani Ira , Gunge Deepti , Pretorius Victor , Malhotra Atul , Sun Xin , Duran Jason , Hepokoski Mark , Crotty Shane , Coufal Nicole G , Meier Angela , Crotty Alexander Laura E
Published: May 2021

Background

Increased inflammation has been well defined in coronavirus disease 2019 (COVID-19), while definitive pathways driving severe forms of this disease remain uncertain. Neutrophils are known to contribute to immunopathology in infections, inflammatory diseases, and acute respiratory distress syndrome, a primary cause of morbidity and mortality in COVID-19. Changes in neutrophil function in COVID-19 may give insight into disease pathogenesis and identify therapeutic targets.

Methods

Blood was obtained serially from critically ill COVID-19 patients for 11 days. Neutrophil extracellular trap formation (NETosis), oxidative burst, phagocytosis, and cytokine levels were assessed. Lung tissue was obtained immediately postmortem for immunostaining. PubMed searches for neutrophils, lung, and COVID-19 yielded 10 peer-reviewed research articles in English.

Results

Elevations in neutrophil-associated cytokines interleukin 8 (IL-8) and interleukin 6, and general inflammatory cytokines IFN-inducible protien-19, granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin 1β, interleukin 10, and tumor necrosis factor, were identified both at first measurement and across hospitalization (P < .0001). COVID-19 neutrophils had exaggerated oxidative burst (P < .0001), NETosis (P < .0001), and phagocytosis (P < .0001) relative to controls. Increased NETosis correlated with leukocytosis and neutrophilia, and neutrophils and NETs were identified within airways and alveoli in lung parenchyma of 40% of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–infected lungs available for examination (2 of 5). While elevations in IL-8 and absolute neutrophil count correlated with disease severity, plasma IL-8 levels alone correlated with death.

Conclusions

Literature to date demonstrates compelling evidence of increased neutrophils in the circulation and lungs of COVID-19 patients. Importantly, neutrophil quantity and activation correlates with severity of disease. Similarly, our data show that circulating neutrophils in COVID-19 exhibit an activated phenotype with enhanced NETosis and oxidative burst.
Perinatal DEHP exposure induces sex- and tissue-specific DNA methylation changes in both juvenile and adult mice
Authors: Liu Siyu , Wang Kai , Svoboda Laurie K , Rygiel Christine A , Neier Kari , Jones Tamara R , Cavalcante Raymond G , Colacino Justin A , Dolinoy Dana C , Sartor Maureen A
Published: May 2021

Di(2-ethylhexyl) phthalate (DEHP) is a type of phthalate plasticizer found in a variety of consumer products and poses a public health concern due to its metabolic and endocrine disruption activities. Dysregulation of epigenetic modifications, including DNA methylation, has been shown to be an important mechanism for the pathogenic effects of prenatal exposures, including phthalates. In this study, we used an established mouse model to study the effect of perinatal DEHP exposure on the DNA methylation profile in liver (a primary target tissue of DEHP) and blood (a common surrogate tissue) of both juvenile and adult mice. Despite exposure ceasing at 3 weeks of age (PND21), we identified thousands of sex-specific differential DNA methylation events in 5-month old mice, more than identified at PND21, both in blood and liver. Only a small number of these differentially methylated cytosines (DMCs) overlapped between the time points, or between tissues (i.e. liver and blood), indicating blood may not be an appropriate surrogate tissue to estimate the effects of DEHP exposure on liver DNA methylation. We detected sex-specific DMCs common between 3-week and 5-month samples, pointing to specific DNA methylation alterations that are consistent between weanling and adult mice. In summary, this is the first study to assess the genome-wide DNA methylation profiles in liver and blood at two different aged cohorts in response to perinatal DEHP exposure. Our findings cast light on the implications of using surrogate tissue instead of target tissue in human population-based studies and identify epigenetic biomarkers for DEHP exposure.
Minimal invasive temporary percutaneous right ventricular circulatory support after left ventricular assist device implantation
Authors: Natanov Ruslan , Ricklefs Marcel , Madrahimov Nodir , Fleissner Felix , Haverich Axel , Kühn Christian
Published: May 2021

OBJECTIVES

Cardiogenic shock is a life-threatening situation with high mortality rates. Mechanical unloading of the left ventricle may be achieved via left ventricular assist device (LVAD) implantation. Postoperative right ventricular (RV) failure, however, has very limited therapeutic options and is associated with increased postoperative mortality. In this paper, we describe a percutaneous right heart bypass for temporary postoperative RV support.

METHODS

We retrospectively examined all patients receiving percutaneous RV mechanical support after LVAD implantation. All patients receiving trans-jugular mechanical right heart bypass during or after LVAD implantation in our tertiary medical centre between November 2014 and December 2019 were examined retrospectively. The venous draining cannula was placed in the femoral vein; the pulmonary cannula was placed in the pulmonary artery using fluoroscopy.

RESULTS

In total, 14 patients received RV support using the trans-jugular technique. Mean age was 48.4 ± 14.9 years. Nine patients were treated with mechanical circulatory support before LVAD implantation. Biventricular support was done in 7 patients. All patients were treated with an Heartware HVAD . Mean postoperative intensive care unit stay was 46.3 ± 32.4 days. Mean right heart bypass support time was 10.6 ± 4.3 days. Twelve patients (86%) could be bridged to RV recovery, RV assist device implantation or heart transplantation.

CONCLUSIONS

Percutaneous RV mechanical support is feasible, safe and shows acceptable outcome. Early implantation of RV support may contribute to successful outcome after LVAD implantation.
Incidences and Determinants of Functional Cure During Entecavir or Tenofovir Disoproxil Fumarate for Chronic Hepatitis B
Authors: Hsu Yao-Chun , Yeh Ming-Lun , Wong Grace Lai-Hung , Chen Chien-Hung , Peng Cheng-Yuan , Buti Maria , Enomoto Masaru , Xie Qing , Trinh Huy , Preda Carmen , Liu Li , Cheung Ka-Shing , Yeo Yee Hui , Hoang Joseph , Huang Chung-Feng , Riveiro-Barciela Mar , Kozuka Ritsuzo , Istratescu Doina , Tsai Pei-Chien , Accarino Elena Vargas , Lee Dong-Hyun , Wu Jia-Ling , Huang Jee Fu , Dai Chia-Yen , Cheung Ramsey , Chuang Wan-Long , Yuen Man-Fung , Wong Vincent Wai-Sun , Yu Ming-Lung , Nguyen Mindie H
Published: May 2021

Background

Long-term incidences and baseline determinants of functional cure (hepatitis B surface antigen [HBsAg] seroclearance) during entecavir (ETV) or tenofovir disoproxil fumarate (TDF) treatment are incompletely understood.

Methods

This is an international multicenter cohort study of treatment-naive patients with chronic hepatitis B who started ETV or TDF treatment without baseline cancer. Patients were observed for HBsAg seroclearance until death or loss to follow-up. We calculated the incidences and explored the baseline determinants of HBsAg seroclearance using competing risk regression.

Results

The analysis included 4769 patients (median age, 50 years; 69.05% male), with a median follow-up of 5.16 years (26 614.47 person-years). HBsAg clearance occurred in 58 patients, yielding a 10-year cumulative incidence of 2.11% (95% confidence interval, 1.54%–2.88%) and an annual rate of 0.22% (.17%–.28%). Baseline predictors included low-level viremia with hepatitis B virus DNA <2000 IU/mL (adjusted subdistribution hazard ratio, 3.14 [95% confidence interval, 1.80–5.49]), elevated serum alanine aminotransferase >200 U/L (3.68 [2.07–6.53]), serum bilirubin (1.11 per mg/dL; [1.06–1.17 mg/dL]), and fatty liver (1.84 [1.03–3.29]).

Conclusion

HBsAg seroclearance rarely occurs in patients with chronic hepatitis B treated with ETV or TDF and is associated with low-level viremia, alanine aminotransferase flare, bilirubin level, and fatty liver.

Functional cure of hepatitis B virus infection rarely occurred at an average annual rate of 0.22% during first-line oral antiviral treatment, with higher chances observed in patients with low-level viremia, high-level aminotransferase flare, elevation of serum bilirubin, and fatty liver.