bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical research on sealing performance of high speed and high pressure centrifugal compressor seal
Authors: Wu Jun , Zhao Zhenxing , Dai Lu , Lao Xingsheng , Lv Weijian
Published: January 2020

In this paper, two seal schemes of stepped labyrinth seal and straight through-hole seal are selected for the shaft end seal of S-CO2 centrifugal compressor with the output of 100kW. The full three-dimensional CFD numerical simulation method is adopted to analyze and compare the sealing characteristics of two S-CO2 seals in S-CO2 centrifugal compressor under different outlet back pressures and sealing gaps. The results show that the leakage flow rate of S-CO2 stepped labyrinth seal and through-hole seal increases with the decrease of back pressure. The leakage flow rate of the stepped labyrinth seal and the through-hole seal reaches the corresponding critical value when the back pressure is 1.0 MPa and 3.0 MPa respectively. The critical leakage flow rate of the stepped labyrinth seal and the through-hole seal under the condition of 0.1 mm sealing gap is 0.158 kg/s and 0.128 kg/s respectively. Compared to the through-hole seal, the stepped labyrinth seal can withstand greater pressure differentials at the same sealing gap and has superior S-CO2 sealing performance.
Analysis of Factors Influencing the Resistance of a Type of Air Filter Paper Based on SPSS
Authors: Qi Peiyun , Yan Chunxiao , Zang Chuanqin , Xu Jiayu , Huang Xingqi , Dai Xuezhi , Jin Yanren , Zhao Ting
Published: January 2020

The thicknesses, basis weights and resistances of a type of air filter paper randomly sampled were tested by experiment. The statistical analysis of the test data was carried out by multiple linear regression analysis of the statistical software SPSS19.0. The conclusion were as follows: when the paper had a basis weight variation from 55.2 g/m2 to 59.8g/m2 and a thickness variation from 0.385mm to 0.406mm, α=0.05, basis weight variation on resistance existed significant influence, the regression equation was Δp=2.551w, correlation coefficient R2=0.83; thickness variation on resistance did not exist significant influence.
Diamond Forming Tool Innovative Design Based on Segments Thickness Dimension Compensation
Authors: Xing Baoliang , Zheng Chunying , Wang Jing , Xue Shanshan , Cao Huiying , Zhang Zhengmei
Published: January 2020

Based on machining experiments the diamond forming tool wear degrees of irregular area were studied, the tool wear rate mathematical model was deduced by regression analysis and the improvement project of tool was innovatively designed. Through the diamond forming tool segments thickness dimension compensation, the tool wear of irregular area can be uniformly achieved, the performance of diamond forming tool has been increased highly and the diamond forming tool life is greatly extended.
Research on Influencing Factors on Rheological Properties of Chitosan/Starch Film Slurry
Authors: Sun Kaiqiang , Li Jianyong , Li Fangyi , Zhou Xin , Wang Zunyi , Wang Lei , Sun Xu , Cui Jinfeng , Zhang Chuanwei
Published: January 2020

In order to improve the industrial production efficiency of chitosan/starch film, reducing slurry rheology is an important measure. This paper explored that the temperature, chitosan starch ratio, plasticizing different components had a great impact on the rheology of the slurry. As the starch content and temperature increased, the rheology of the slurry first decreased and then increased. Finally, it was determined that when the slurry was transported at 60°C with chitosan: starch = 1:1.5 and only the chitosan was plasticized, the viscosity was the minimum. The viscosity of the slurry was related to the hydrogen bond formed by the slurry. The more hydrogen bonds, the greater the viscosity. Plasticizing chitosan destroyed the crystal structure and facilitated the formation of the network structure, which was conducive to the shear flow of the slurry.
Preliminary Study on the Innovative Design of Original Bamboo Furniture Based on the Coordination Evolution Rules of Subsystems of TRIZ Theory
Authors: Dong Wenying , Dai Xiangdong , Yao Jin Jin , Xiong Yi
Published: January 2020

The original bamboo furniture is green and environmentally friendly and is a good substitute for wood. But at present, the design of original bamboo furniture develops slowly and its added value is not very high. By applying the coordinated evolution principle of subsystems in TRIZ technology evolution theory, this research makes a preliminary exploration on the innovative design methods of original bamboo furniture in form and structure in the purpose of bringing inspiration and new thinking to the innovative design of original bamboo furniture. In this way, promoting the development of original bamboo furniture design faster and better.
Measurement of in-plane thermal conductivity of self-suspended thin films
Authors: Xu Liqiang
Published: January 2020

A method for in-plane thermal conductivity measurement of self-suspended thin films by steady-state infrared thermal thermography is introduced. Based on the one-dimensional heat conduction equation, a theoretical model of temperature distribution on the surface of thin film at steady state is established. The simulation results show that the error between in-plane thermal conductivity and theoretical value is less than 3% when the temperature rise of the film is less than 5K. By measuring the boundary temperature and thickness of the film, the in-plane thermal conductivity and emissivity can be obtained simultaneously without measuring the absorption of visible light by the film. Polyimide film with the thickness of 550 nm is experimentally investigated by this method. We find that the in-plane thermal conductivity is 2.15W/mK and emissivity is 0.93 by fitting temperature distribution curve. These results validate the method developed.
Experiment and finite element analysis study on the deflection of aluminum extruded 6063-T5 hollow structural beam
Authors: Ho Minghsiung , Lee Pinghui , Ye Chao , Lin Chipang , Huang Chenfu
Published: January 2020

In this study, the tensile tests were performed on samples extruded from aluminum beam to confirm the material properties of the various parts. Then, the beam was cut into lengths of 1160 mm and 680 mm to perform the bending test, and the beam loading point deformation was recorded. At the same time, the amount of beam deformation caused by three type beam fixing methods was compared. The Solidwork 3D CAD software used to build the beam model and perform finite element analysis. Among them, the analysis results of different boundary conditions were compared with the experimental results. The experimental load conditions were used to calculate the theoretical deformation formula amount through the beam theory deformation formula of material mechanics. It is to compare beam deformation data of experiments, finite element analysis, and theoretical formulas, and explore possible causes of differences.
Research on laser water vapor concentration detection technology in the air-sea flux observation
Authors: Zhang Ke-Ke , Zheng Xue-Yong , Chen Shi-Zhe , Wan Xiao-Zheng , Zhang Ji-Ming , Zhao Qiang , Wang Bo , Qi Liang
Published: January 2020

In the observation of water vapor flux at air-sea interface, the collection frequency of water vapor concentration is more than 10 Hz. High-speed and high-precision measurement of water vapor concentration is an urgent problem to be solved in the observation of water vapor flux at air-sea interface. The ratio of the peak-peak value of second harmonic to the average value of first harmonic is used to measure water vapor concentration based on tunable diode laser absorption spectroscopy. The sensitivity of laser water vapor concentration detection equipment caused by marine salt fog and dust is reduced through precise optical design, and the water vapor concentration at the air-sea interface is calculated using a binary polynomial fitting algorithm. The response frequency of the laser water vapor concentration analyzer is 40 Hz. The water vapor concentration values from the laser water vapor concentration analyzer and LI-7500 CO2/H2O gas analyzer are collected synchronously in real time using LabVIEW software. The comparison results show that they have good consistency in the trend and response speed of water vapor concentration, and the measurement deviation of water vapor concentration is within ±1%. The experimental results show that it can meet the needs of high-speed, high-precision measurement of water vapor concentration in the air-sea interface water vapor flux observation.
Infrared contrast characteristic of satellites
Authors: Lv Xiang-Yin , Jin Wei
Published: January 2020

Using infrared characteristic of space target for detecting and identifying the space target is a kind of effective method. Infrared radiation contrast study of satellite has great significance for both detecting and identifying the satellite, and monitoring satellite condition. In this paper, the method to calculate the radiant heat flux of satellite is given firstly. Then, the mathematical model of the surface temperature of satellite is obtained and the numerical calculation is done. The calculated numerical data is similar to the telemetry data, which proves that the orbit flux and temperature models are correct. Finally, the infrared radiant contrast of every surface on the satellite’s body and solar panels were calculated and analyzed. The results show that, on the one hand, satellite infrared radiation in long wave infrared band is larger than that in medium wave infrared band. From the point of view of the range coverage, use the long wave infrared is more advantageous to detect satellite. And on the other hand, satellite infrared contrast in medium wave infrared band is much larger than that in long wave infrared band. From the point of view of the resolution of image detail, use the medium wave infrared is more advantageous to identify satellite.
Effect of Al Content on the Stability of MgF2 Powder in Air at High Temperatures
Authors: Chen Hukui , Huang Jie , Jiang Hongli
Published: January 2020

The effect of Al on the stability of MgF2 powder at 600–1000 °C in air has been investigated by XRD, EDS and SEM. It is found that the thermal stability of MgF2 is strongly influenced by both Al content and temperature. With the increase of Al content and temperature, MgF2 was gradually oxidized to MgO, that is, the thermal stability of MgF2 was gradually lowered. The reason that the addition of Al causes the thermal stability of MgF2 to decrease may be related to the oxidation of Al and the formation of MgAl2O4 at high temperatures.
Simulation on Molten Pool Characteristics of Al2O3 Laser Selective Melting Based on Energy Input Model
Authors: Chen Xiaobing , Sun Quan , Sun Quanping , Wu Haibing , Xu Qian
Published: January 2020

In order to obtain the formation rule of molten pool characteristics in SLM process of ceramics, an energy input model for SLM process of Al2O3 ceramics is established. The model is related to laser power P, scanning speed v, scanning spacing s and thickness h of powder layer. The influence of process parameters in the energy model on molten pool characteristics is analyzed by simulation of temperature field of multi-layer and multi-channel SLM process. The simulation results show that when the laser power P is 105W, the scanning speed v is 50mm/s, the initial temperature of powder is 330°C and the thickness of powder layer is 0.20mm, the molten pool formed is easy to form Al2O3 ceramic specimens.
Influences of Feedstocks and Laser Remelting on Erosion Resistance of Al2O3-13wt.%TiO2 Coatings Prepared by Plasma Spraying
Authors: Wang Dongsheng , Zhou Xinghua
Published: January 2020

Conventional and nanostructured ceramic coatings were prepared with conventional and nanostructured aggregate Al2O3-13wt.%TiO2 ceramic powders through plasma spraying and plasma spraying-laser remelting combined technique. Influences of feedstocks and laser remelting on erosion resistance of the prepared coatings were discussed, and the erosion failure mechanisms of four types of coatings were discussed. Results demonstrate that compared with coatings prepared by plasma spraying, the coating prepared by laser remelting has better erosion resistance. Given the equal conditions, nanostructured coating shows stronger erosion resistance than conventional coating. Conventional ceramic coating shows typical brittle erosion characteristics and nanostructured ceramic coating also shows brittle erosion characteristics, accompanied with certain degree of plastic erosion characteristics. Erosive wearing of plasma coating is mainly lamellar peeling, accompanied with certain degree of brittle ceramic particle crushing. Coating prepared by laser remelting present crack initiation and propagation on near surface, finally leading to crystal crushing and peeling of remelting layers.
Mechanical properties of the wet mixed geopolymer concrete based on CDG and Slag cementitious materials in ambient curing temperature
Authors: Zha Xiaoxiong , Wang Kai , Zhu Jiayuan
Published: January 2020

Although considerable research has been conducted on alkali-activated fly ash cementitious materials for geopolymer concrete production, few of which concentrated on the slag-based geopolymer concrete. This paper presents the results of an experimental investigation on the 7-day & 28-day compressive strength, as well as 28-day flexural strength of the wet mixed geopolymer concrete based on CDG and slag cementitious materials cured at ambient temperature. A total of 90 specimens were tested. The cementitious materials content, sand ratio, as well as the liquid-solid ratio were selected as the main parameters. Besides, the new alkali activator system was adopted to prepare the geopolymer. Effects of these variables on the compressive and flexural behavior of the wet mixed geopolymer concrete are plotted throughout this paper.
Prediction of flue gas acid dew point temperature distribution range in boilers
Authors: Bi Cheng , Li Debiao , Yang Xu , Lu Yuan , Zhang Jianlong
Published: January 2020

Prediction of the acid dew point temperature of flue gas has a great effect on the heat exchangers design or control as recover energy from the boiler exhaust gas. The present study focuses on the prediction of the flue gas acid dew point temperature as well as its distribution interval, which can further help to prevent and resist the low temperature corrosion from the flue gas. Popular prediction models of acid dew point are reviewed. The 1973 version of Soviet Union calculation standard model has a priority to calculate the mean acid dew point prediction in coal fired boilers, and the Okkes model is also recommended for different types of boilers. Several groups of experimental and published data are substituted to different prediction models for analysis, and the results show that the Verhoff & Banchero model and Haase & Borgmann model can be explored to calculate the upper and lower limits of the distribution interval of the acid dew point.
Study on the effect of molten ash on the combustion process for biomass
Authors: Xu Yao , Zou Xun , Jin Shuai , Zhai Ming , Dong Peng
Published: January 2020

In this study, the high temperature visual test system (HTVTS) and high temperature thermogravimetric test system (HTTTS) were set up to observe the formation process of ash, thereby analyzing the mechanism of biomass melt combustion. Then, the effect of the molten ash on the combustion process was investigated. Results show that during the combustion, once the local temperature of the biomass particle is higher than the ash melting temperature, the generated ash could be melted and contracted into a spherical shape by the surface tension. The molten ash located in the interior of the biomass particle adhere to the char surface, thereby preventing the contact between char and oxygen. The molten ash located on the surface of biomass particle could drop down from the surface of biomass particle. When the conversion rate is higher than 45%, the effect of molten ash on the reaction rate becomes more obvious.
Structure optimization and thermal field analysis of biogas derived methane fueled Solid Oxide Fuel Cell
Authors: Zhan Ruobing , Wang Yang , Du Qing , Jiao Kui
Published: January 2020

The suitability for using various gaseous fuels makes the Solid Oxide Fuel Cell (SOFC) the most promising heat-electricity cogeneration device. Thermal field distribution of SOFC directly determines whether the cell is operating in sufficient catalytic activity and weakened by thermal stress. For biogas derived methane fueled SOFC, the internal reforming reactions can cause the inhomogeneous temperature distribution. So it is crucial to optimize the thermal field to achieve optimal cell operation state. In this paper, a 3D muti-physics model is developed to study the improvements of a new cathode flow field structure. When adopting new cathode structure, the power density increases by over 11%, and the maximum temperature gradient can be evidently reduced.
Numerical investigations on entropy generation in cross-wavy channels
Authors: Shi Xusheng , Wang Yongwei , Huai Xiulan
Published: January 2020

The numerical study to research the influence of ratio of channel amplitude to pitch of cross-wavy on entropy generation is conducted in this paper. In Reynolds number range of 200-1200, five types of cross-wavy channel are analyzed. The simulation results show the thermal entropy generation rising rate is fast when Reynolds number less than 700 and then flat. In addition, it is smaller with increasing channel amplitude to pitch value. The frictional entropy generation increases almost linearly with Reynolds number. However, it is much less than thermal entropy generation under the same conditions. In brief, the channels which have larger ratio of amplitude to pitch can reduce the total irreversibility to the least under the same flow conditions.
Research of a blackbody cavity for effective integrated emissivity with finite volume method
Authors: Liu Bo , Wang Chong-yuan , Xu Jun-long , Wang Zhi-yuan , Zhu Peng-fei
Published: January 2020

Temperature is a critical parameter for energy efficiency measurement evaluation. High-performance blackbody radiation source is the key equipment for highly precision reproduction of radiation temperature. The effects of blackbody geometric parameters, cavity material emissivity, and temperature distribution on integrated effective emissivity e and normalized spatial integrated effective emissivity variation were studied by finite volume method. The numerical simulation has a good agreement with the result computed by Monte-Carlo method. The results show that the isothermal cavity has a higher e and a smaller than the non-isothermal. A smaller aperture diameter Da
and a higher material emissivity are benefit for a higher e and a more uniform distribution on detector of e. The results provide references for the design and study on high-performance blackbody radiation source.
The Range and Standards of Yang Dongfang Temporal Water Temperature Variation Angle II. Model Application
Authors: Yang Dongfang , Ren Haoyuan , Yang Dong , Fang Jing , Li Haixia
Published: January 2020

According to the investigation materials about water bodies of Jiaozhou Bay in May, August and October 1979, this paper studied the changing process of water temperature in the surface and bottom waters. Based on the definition and model of Yang Dongfang temporal water temperature variation angle, the results indicated that in the water bodies of inside, around and outside of bay mouth, Viewing the waters inside of bay mouth, around the bay mouth and outside of bay mouth as one water body, the length of variation range of Yang Dongfang temporal water temperature variation angle is 2.98°when heating the surface of this water body, and 0.14°when heating the bottom. The length of variation range of this angle is 6.87°when cooling the surface and 7.28°when cooling the bottom, which displays the changing process of water temperature under the heating or cooling condition.
Numerical simulations of the combustion characteristics for a 660MW tangentially fired boiler with different closing-to-wall air velocities
Authors: Liang Kui , Liu Guangkui , Liu Feng
Published: January 2020

To solve the problem of high temperature corrosion of water-cooled wall of power station boiler, this paper proposes a new type technology of closing-to-wall air. Taking a 660MW tangentially fired boiler as the research object, numerical simulations were conducted to study the influences of closing-to-wall air velocity on the combustion characteristics in the boiler. The results show that O2 concentration in the flowing region is significantly increased, CO concentration is significantly reduced, and the oxidizing atmosphere in the near-wall region is enhanced. As the closing-to-wall air velocity increases, the rigidity of the airflow is gradually stronger, and the penetration depth of the airflow increases, so that the coverage area of the airflow is increased. The influence of the closing-to-wall air velocity on the combustion effect of the boiler is negligible.
Analysis of Hydrogen Corrosion of Water Wall Tube of a Power Plant Boiler
Authors: Chengchuan Tian , Chong Jiang
Published: January 2020

During the operation of a power station boiler with the rated evaporation of 1025 t/h, its water wall tube, which is made of SA-210C, bursts continuously. Based on the fracture analysis, material inspection, metallographic examination, energy spectrum analysis and mechanical property analysis of the tube sample, this paper confirms that the cause of the water wall tube failure is hydrogen corrosion, which is accelerated by the copper impurity.
Optimization design method of PRHRS air heat exchanger based on natural circulation characteristics
Authors: Wang Yandong , Chen Yongdong , Wu Xiaohong , Yu Zhiqiang , Cheng Pei
Published: January 2020

Passive residual heat removal system (PRHRS) was the key equipment to ensure the inherent safety of the fourth generation of nuclear reactors, which can effectively reduce the probability of core meltdown in the event of an accident. A multi-physics coupling model of sodium cooled fast reactor PRHRS was established in this paper, which based on the natural circulation characteristics of PRHRS. The model was analytically calculated according to the flow balance and energy balance, and finally the model was dynamically balanced. The influence of the tube spacing of the serpentine finned tube and the opening area of the air door on the thermal behavior of the system was analyzed through PRHRS model, and the optimal design method of the air heat exchanger (AHX) of PRHRS was mastered. The research results provide a theoretical basis for the rational design of the air heat exchanger and the safe operation of the sodium cooled fast reactor PRHRS.
Numerical Simulation Research on Agglomeration between Coal-fired Fly Ash Fine Particulate and Atomized Droplets
Authors: Guo Yiquan , Zhang Junying
Published: January 2020

In this paper, the interaction process between atomized droplets and particles after spraying chemical agglomeration solution was numerically simulated, the force model of particles in agglomeration solution was established, and the effects of density, viscosity, flow rate of agglomeration solution, and diameter of atomized droplets and other factors on the velocity, quality, diameter and number of particles after agglomeration were analyzed. The simulation results showed that the speed, mass, diameter and number of particles after agglomeration were greatly affected by the physical and chemical parameters of the chemical agglomeration solution. Increasing the density and viscosity of the solution could increase the variation trend of each characteristic quantity of particles. As the flow rate of agglomeration solution and diameter of atomized droplets became larger, the collision probability between the solution and particles got higher as a result. Since the particles gradually agglomerated, their mass and diameter increased. As their speed gradually decreased, the probability of collision and agglomeration with chemical agglomeration solution decreased as well.
Design and Research of High-accuracy and Intelligence Test Device for Gas Water Heater Energy Efficiency
Authors: Wu Zhongjie , Xu Dinghua , Zhang Haiyun , Hang Chenzhe , Zhou Junhong
Published: January 2020

The research subject aims to solve the defects of slow test speed and inefficient for gas water heater energy efficiency. It not only applies modern sensor technology, high reliability data acquisition card, solenoid valve control technology and stable industrial computer, but also adopts LabVIEW language, PID control technology and flow stability judgment algorithms to develop an efficient, accurate and intelligent test system for gas water heater energy efficiency. The test results shows that the measurement repeatability of the test device is superior to the artificial test device and common intelligent test device, and the assessed measurement uncertainty meets the requirements of the national supervision and inspection technical specifications.
Numerical study on condensation of steam/air mixture inside corrugated low finned tubes
Authors: Ren Bin , Lu Hongliang , Tang Xiaoying , Du Yannan , Si Jun , Ren Facai
Published: January 2020

Corrugated low finned tubes are the specical spirally corrugated tubes, which can enhance the condensation heat transfer with and without noncondensable gas. In this paper, a numerical model on the basis of diffusion layer theory was established to investigate the local heat transfer characteristic inside corrugated low finned tubes. The local parameters contain bulk temperatures, gas mass fraction, heat transfer coefficient and heat flux. The results showed that the bulk temperatures decreased along the condenser tube but the noncondensable gas mass fraction displayed the opposite trend. The local heat transfer coefficient and heat flux decrease along the condenser tube especially near the outlet. Of the five enhanced tubes, #5 tube had the best overall heat transfer performance, but it also had the fastest rate of decline as condensation progressed, indicating that the rib was the main influence factor compared with pitch.
Heat Transfer Characteristics and Energy Efficiency Analysis of Finned Tube Heat Exchangers
Authors: Wang Zhenchuan , Liu Chao , Zhang Songsong
Published: January 2020

Flow and heat transfer characteristics of the integral finned tube heat exchanger are studied by the numerical simulation method in the present paper. The energy efficiency levels of two types of finned tube heat exchangers (aligned finned tube and staggered finned tube) are evaluated by PEC method. The heat transfer intensity of different finned tube heat exchangers was evaluated by the field synergy principle. When the tube spacing ratio (S1/S2=1) is small, the field synergy of staggered finned tube is similar to the aligned finned tube, and the PEC index is less than 1; when the spacing ratio (S1/S2=3) is large, the field synergy of the staggered finned tube get much stronger than the aligned finned tube, and the PEC index is larger than 1 as the Re≥8×104. Considering both the change of heat transfer intensity and the increase of resistance, it is recommended to evaluate the energy efficiency level of finned tube heat exchanger by PEC method.
Effect of PS-g-MAH Content on ABS/PC Composites
Authors: Zhang Q , Wen J , Chen B , Yin L , Zhu Z F
Published: January 2020

Acrylonitrile-Butadiene-Styrene (ABS) is a common plastic which used in many fields with two-phase system Polycarbonate (PC) is a high-performance amorphous engineering thermoplastics. ABS/PC composites were researched in many academic papers and used in many fields. Polystyrene(PS) grafted with maleic anhydride (MAH)( PS-g-MAH) on ABS/PC composites is studied in this article. The tensile strength and elongation at break of ABS/PC blends have the maximum value when the content of PS-g-MAH is 3%. Tg of ABS in blends increase with the content of PS-g-MAH, which maybe induced by the increase of ABS/PC interface compatibility. From the photo of SEM, the addition of PS-g-MAH improves the compatibility of the interface of the two phases, leading to an increasing trend in the size of PC particles.
Finite Element Study on Chain-Die Forming of an AHSS Channel with Variable Depth
Authors: Bene F F M , Liang Z Y , Yang H , Li D Y , Ding S C
Published: January 2020

A novel manufacturing technology called chain-die forming was in recent years proposed by Dr. Ding as an alternative to conventional roll forming. Mainly applied in the automotive industry, its prolonged deformation range enables the forming of advanced high strength steels (AHSS) with considerably reduced residual strain, which enables an adequate response to the increasing market requirements of this industry. In this paper, the finite element simulation of chain-die forming an AHSS channel with variable depth is performed. For more accurate predictions, the Bauschinger effect is well considered through the Chaboche hardening model implemented. The residual plastic strain and thickness distributions of the U shaped variable-depth profile are numerically evaluated. The forming limit at a critical zone is analyzed and the predicted magnitude of springback after forming is also calculated. The results portray the forming feasibility and strength of the chain-die forming technology as a valid alternative solution to stamping and roll forming, which are commonly used methods to manufacture such products. In one pass, a complete profile is achieved as opposed to roll forming, with no product defect such as wrinkling or cracking with limited springback development.
Study on the Correlation between the Texture Depth of Volume Replacement Method and the Texture Depth of Spectral Reproduction Method
Authors: Jinning Zhang , Yishu Zhou , Pengfei Wang , Huayang He
Published: January 2020

Through theoretical research and actual road condition analysis, this paper establishes the simulation calculation model and the spectrum analysis model. Through the spectrum inversion, the stable road surface state is obtained, and the conversion relationship between the reconstruction depth of the spectral reproduction method and the structural depth of the volume displacement method is obtained. Through the conversion relationship of a typical single spectrum, the relationship between SMTD and TD is obtained under each type of standard waveform. Actually, in the process of sand paving, due to the presence of the exposed part, the SMTD and TD in the actual road surface are not positively correlated, thereby correcting the relationship between SMTD and TD. The acquired road surface data is modeled by MATLAB, and the analog waveform is made according to the actual waveform, and the reduced order decomposition is performed to determine the range of a. The intercept b value is determined by comparing the experimental spectra before and after sanding. This paper solves the problem that the detection mechanism needs to perform statistical correlation test in accordance with the requirements of JTG-E60 regulations to meet the requirements of pavement assessment.
A Method for Calibrating Thrust of Satellite Based on the Attitude Variety On-orbit
Authors: Ji Jialong , Gao Yong , Zhang Ali , Lin Qian
Published: January 2020

The propulsion system of satellites is usually used for orbital controlling and attitude-adjusting. And the thrust of thrusters is always calibrated by ground test. A method of calibrating the small thrust of thrusters used for satellites on-orbit is presented in this paper. The application of this method is based on the variety of the attitude of the satellite. And the rotate speed of reaction wheel, the star sensor, and the scopperil, and other components in satellite are utilized in this method. The ground test of 1N thrusters was also carried out, and the thrust calibration test of the same thrusters was performed on-orbit according to this method described here. Both the test were compared, and the results show that both the data are coincident, which means that the method is fit for calibrating small thrust of satellites on-orbit.
Using constrained mixture design method for optimizing the properties of organoclay filled ethylene-octene copolymer nanocomposites
Authors: Tayefi Masoud , Razavi-Nouri Mohammad , Sabet Alireza
Published: January 2020

The mixture design method was used to model the physical and mechanical properties of ethylene-octene copolymer (EOC) nanocomposite containing organically modified montmorillonite (OMT) which were cross-linked dynamically by various amounts of dicumyl peroxide (DCP). A mixture design technique with three components was employed to assess the correlations between the selected properties of the nanocomposites and the component values. For this purpose, EOC, OMT and DCP content were selected as the components. The influences of these components were studied on the tensile strength, modulus at 100% strain, strain at break, x-ray peak intensity and the initial slope of the logarithm of storage modulus versus the logarithm of angular frequency of the nanocomposites prepared. The regression equations of the models as well as contour plots were generated for the properties studied. Good agreements were found between the experimental results and those predicted by the models. The contour plots of each property were overlaid within the applied constraints to discover the combination of factor ranges that provided the nanocomposite with optimal performance.
Effect of ZnS nanowire ARC on CZTS/CdS thin film solar cell by Nebulizer Spray Pyrolysis Technique
Authors: Fathima M Ismail , Arulanantham A M S , Wilson K S Joseph
Published: January 2020

The main intention of this experimental work is to eliminate the reflection of the CZTS/CdS thin film solar cell by depositing the ZnS Antireflection coating (ARC) by Nebulizer Spray Pyrolysis Technique. The CZTS/CdS thin films with and without ZnS Antireflection coating (ARC) deposited using nebulizer spray pyrolysis method is reported in this work. The prepared films were characterized by X-ray diffraction, scanning electron microscopy and UV–Vis spectroscopy analysis. Structural parameters such as lattice constants, texture orientation factor, micro strain, dislocation density and crystallite size were estimated using XRD data. The efficiency of CZTS/CdS solar cell is calculated using I-V characteristics. The experimental results exhibit the short circuit current increased from 9.269 × 10−5A to 1.250 × 10−4A and efficiency raised from 0.21% to o.45%. with ZnS as a ARC. The theoretical quantum efficiency of CZTS solar cell with ZnS ARC is increased from 0.020% to 0.030%. The results indicates that the ZnS ARC is one of the perfect ARC in the CZTS solar cell.
Effect of empty fruit bunches microcrystalline cellulose (MCC) on the thermal, mechanical and morphological properties of biodegradable poly (lactic acid) (PLA) and polybutylene adipate terephthalate (PBAT) composites
Authors: Nor Amira Izzati A , John W C , Nurul Fazita M R , Najieha N , Azniwati A A , Abdul Khalil H P S
Published: January 2020

Nowadays, awareness of the environment is rising among society. Thus, more researches on the utilization of biodegradable polymer as an alternative to non-biodegradable polymers have been published. Among various biopolymers, Poly (lactic acid) (PLA) and polybutylene adipate terephthalate (PBAT) have received a lot of attention because they can be processed using most of the conventional polymer processing methods. PLA is high in strength and modulus, but it is brittle while PBAT is flexible and tough. Thus, PBAT is a good candidate for the toughing of PLA. But when the PLA is blending with PBAT, a certain strength of PLA may be affected. Hence, the reinforcement material is required to improve weakened strength. In this study, PLA was blended with PBAT at various ratios (PLA: PBAT = 90: 10, 80: 20, 70: 30) with a melt‐blending method. The PLA/PBAT blends at a blend ratio of 80: 20, exhibited optimum mechanical performance. Then, PLA/PBAT blends at a blend ratio of 80: 20 was reinforced with different content of EFB-MCC (1 wt%, 3 wt% and 5 wt%) using an internal mixer. The PLA/PBAT blends reinforced with EFB-MCC composites were produced using the compression moulding method. The mechanical, thermal and morphology properties of the composites were investigated. The impact strength of PLA/PBAT blend after addition of both C-MCC and EFB-MCC up to 5 wt% was reduced. The morphological observations from SEM proved the occurrence of the MCC agglomeration in PLA/PBAT blend. DSC results showed trivial changes between the Tg and Tm of PLA/PBAT blend with PLA/PBAT blend reinforced with both types of MCC. TGA results demonstrated that the PLA/PBAT blend reinforced with EFB-MCC has better thermal stability compared to C-MCC. However, further research is needed to improve the interfacial properties of the immiscible PLA/PBAT by compatibilization and enhance the properties of the MCC reinforced PLA/PBAT blend composites.
Transport evidence of mass-less Dirac fermions in (Cd1−x−yZnxMny)3As2 (x + y = 0.4)
Authors: Zakhvalinskii V S , Nikulicheva T B , Pilyuk E A , Lähderanta E , Shakhov M A , Ivanov O N , Kochura E P , Kochura A V , Aronzon B A
Published: January 2020

Charge carriers parameters on a 2D-layer surface for (Cd1−x−yZnxMny)3As2 (y = 0.08) (the concentration

n

2
D

 = 1.9 × 1012 cm–2, the effective value of the 2D-layer

d

2
D

=

n

2
D

/

n

3
D

 = 14.5 nm, the wave vector

k

F

 = 0.1 nm–1, the charge carriers relaxation time due to dispersion

τ

D

 = 1.8 × 10–13 s, the velocity of charge carriers on Fermi surface

v

F

=

ℏ

k

F

/

m

c

 = 2.65 × 105 m s−1, the mean free path

l

F

=

v

F

τ

D

 = 47.7 nm) were determined. It was found that the dependence of the cyclotron mass m

с
(0)/m0 on Fermi wave vector k

F
for (Cd1−x−yZnxMny)3As2 (y = 0.08) is in compliance with a theoretical linear dependence, that describes mass-less Dirac fermions.
Electrospun TiO2 nanofiber electrodes for high performance supercapacitors
Authors: Kuchi Charan , Narayana A Lakshmi , Hussain O M , Reddy P Sreedhara
Published: January 2020

Nanofibers are one dimensional (1D) nanoarchitecture materials having high surface-to-volume ratio which provides improved ion diffusion and high mechanical strength to prevent volume expansion during electrochemical process and enhance the cycle stability. In the present study, TiO2 nanofibers (TNFs) were successfully synthesized on an aluminum collector with a polymer concentration of 9 wt % by cost-effective electrospinning technique followed by annealing at a temperature 500 °C. The XRD spectrum of electrospun TNFs exhibited predominant (101) orientation corresponding to anatase TiO2 with I41/amd symmetry. The estimated average crystallite size is 18 nm. The strongest Raman vibrational mode at 143 cm−1 confirms the phase purity of TNFs. The surface morphological feature depicts interconnected network fibers with a variation in the fiber diameter and the estimated average diameter is ∼150 ± 20 nm. Very smooth surface and homogenously distributed ultra long nanofibers are observed from TEM analysis. The newly fabricated TNF electrode delivered a specific capacitance of 75 Fg−1 and retained 95% capacitance even after 5000 cycles. Moreover, it exhibited energy density and power density values of 24 Whkg−1 and 22.08 Wkg−1 respectively. The large capacitance, high coulombic efficiency and good structural stability demonstrate that TNFs should open up new opportunities for the next-generation high performance supercapacitors.
Anomalous low-temperature saturation effects and negative thermal expansion in the c-axis of highly oriented pyrolytic graphite at the magic angle
Authors: Taallah Ayoub , Shuai Gao , Odunmbaku Omololu , Corrias Anna , Boi Filippo S
Published: January 2020

We report a novel T-XRD and Rietveld-refinement investigation of pyrolytic-graphite samples with high degree of graphene-layer-orientation and misfit-rotational-angle of ∼0.8° in the T-range from 12 K to 298 K. An anomalous variation of the graphitic c-axis which involves firstly negative-thermal-expansion (from 12 K to ∼50 K), a saturation-effect (from 50 K to ∼160 K) and then a positive expansion (from ∼180 K to 298 K) is evidenced. The reported trend is significantly different with respect to that expected by considering the standard-thermal-expansion α-parameter where no saturation-effect is present. SQUID-magnetometry revealed further presence of superconducting-like hysteresis which resemble those observed by Scheike et al.
Laser cladding technique for erosive wear applications: a review
Authors: Singh Sarpreet , Goyal Deepak Kumar , Kumar Parlad , Bansal Anuj
Published: January 2020

Slurry erosion is a serious menace in most of the hydro machine components all around the globe. Slurry erosion is accountable for heavy economic losses. However, some counter measures are being taken to mitigate the effect of sand particles passing through hydro-machine parts and research is also underway to improve the component surface by applying different surface coatings. Laser cladding is a surface deposition process that is used to achieve very good metallurgical bonding with minimum porosity as compared to other surface coating techniques. In this research paper, an attempt has been made to compile the literature related to laser cladding technology, its applications, process parameters, coating materials and their effectiveness to bestow solutions to various types of surface degradation with special emphasis on slurry erosion problems. This paper will serve as a reference for the researchers working in the area of slurry erosion prevention.
Cantor bouquets in spiders’ webs
Authors: Dourekas Yannis
Published: January 2020

For many transcendental entire functions, the escaping set has the structure of a Cantor bouquet, consisting of uncountably many disjoint curves. Rippon and Stallard showed that there are many functions for which the escaping set has a new connected structure known as an infinite spider’s web. We investigate a connection between these two topological structures for a certain class of sums of exponentials.
Defining ‘Integration’ for Total Worker Health®: A New Proposal
Authors: Punnett Laura , Cavallari Jennifer M , Henning Robert A , Nobrega Suzanne , Dugan Alicia G , Cherniack Martin G
Published: January 2020

The effects of work and the conditions of employment on health behaviors and intermediate health conditions have been demonstrated, to the extent that these relationships should be addressed in efforts to prevent chronic disease. However, conventional health promotion practice generally focuses on personal risk factors and individual behavior change. In an effort to find solutions to the myriad of health challenges faced by the American workforce, the U.S. National Institute for Occupational Safety and Health (NIOSH) established the Total Worker Health® (TWH) program. Originally organized around the paradigm of integrating traditional occupational safety and health protections with workplace health promotion, TWH has evolved to a broader emphasis on workplace programs for enhancing worker safety, health, and well-being. Among the research programs and approaches developed by investigators at NIOSH Centers of Excellence for TWH and elsewhere, definitions of ‘integration’ in workplace interventions vary widely. There is no consensus about which organizational or individual outcomes are the most salient, how much to emphasize organizational contexts of work, or which program elements are necessary in order to qualify as ‘Total Worker Health’. Agreement about the dimensions of integration would facilitate comparison of programs and interventions which are self-defined as TWH, although diverse in content. The specific criteria needed to define integration should be unique to that concept—i.e. distinct from and additive to conventional criteria for predicting or evaluating the success of a workplace health program. We propose a set of four TWH-specific metrics for integrated interventions that address both program content and process: (i) coordination and interaction of workplace programs across domains; (ii) assessment of both work and non-work exposures; (iii) emphasis on interventions to make the workplace more health-promoting; and (iv) participatory engagement of workers in pivotal ways during intervention prioritization and planning to develop self-efficacy in addressing root causes, skill transfer, building program ownership, empowerment, and continuous improvement. Thus we find that integration requires organizational change, both to engage two managerial functions with different goals, legal responsibilities, and (often) internal incentives & resources, and also to orient the organization toward salutogenesis. Examples from research activity within the Center for the Promotion of Health in the New England Workplace illustrate how these criteria have been applied in practice.
Length of hospital stay and mortality associated with burns from assault: a retrospective study with inverse probability weighting analysis
Authors: Yamamoto Ryo , Toyosaki Mitsunobu , Kurihara Tomohiro , Sasaki Junichi
Published: January 2020

Background

Burns resulting from assaults account for considerable morbidity and mortality among patients with burn injuries around the world. However, it is still unclear whether unfavorable clinical outcomes are associated primarily with the severity of the injuries. To elucidate the direct relationship between burns resulting from assaults and mortality and/or length of hospital stays, we performed this study with the hypothesis that burns from assault would be independently associated with fewer hospital-free days than would burns from other causes, regardless of the severity of burn injuries.

Methods

We conducted a retrospective cohort study, using a city-wide burn registry (1996–2017) accounting for 14 burn centers in Tokyo, Japan. Patients who arrived within 24 hours after injury were included, and those with self-inflicted burn injuries were excluded. Patients were divided into two groups according to mechanism of burns (assault vs. accident), and the number of hospital-free days until day 30 after injury (a composite of in-hospital death and hospital length of stay) was compared between the groups. To estimate the probability that an injury would be classified as an assault, we calculated propensity scores, using multivariate logistic regression analyses adjusted for known outcome predictors. We also performed an inverse probability weighting (IPW) analysis to compare adjusted numbers of hospital-free days.

Results

Of 7419 patients in the registry with burn injuries during the study period, 5119 patients were included in this study. Of these, 113 (2.2%) were injured as a result of assault; they had significantly fewer hospital-free days than did those with burns caused by accident (18 [27] vs. 24 [20] days; coefficient = $-$3.4 [$-$5.5 to $-$1.3] days; p = 0.001). IPW analyses similarly revealed the independent association between assault burn injury and fewer hospital-free days (adjusted coefficient = $-$0.6 [$-$1.0 to $-$0.1] days; p = 0.009).

Conclusions

Burn from assault was independently associated with fewer hospital-free days, regardless of the severity of burn injuries. The pathophysiological mechanism underlying the relationship should be further studied in a prospective observational study.