bluuebunny/crossref_metadata_2025 huggingface dataset:
The Technological Process of Silver Electrode Printing on Touchscreens
Authors: Zhen Wei
Published: July 2020

A new type of metallic screen embedded in the non-metallic screen, with a mesh count of 230-380 mesh/inch and a wire diameter of 19 μm with an opening rate of 39%, is found through the comparative experiment. The screen has high resilience, suitable mesh count and moderate opening rate. This kind of screen can not only ensure the off-screen effect, but also ensure the high resolution of stencil and printing.
Energy Storage State Identification Of Circuit Breaker Based On Fast Extraction Of Interval Feature Of Vibration Signal
Authors: Xia Xiaofei , Lu Yufeng , Su Yi , Yang Jian , Rao Xiajin , Lu Zecheng
Published: July 2020

Aiming at the problems of slow feature extraction and poor real-time diagnosis of some mainstream state identification methods in actual operation, a fast feature extraction method of vibration signal interval is proposed to identify the energy storage state of circuit breaker. Firstly, according to the kurtosis wavelet modulus maxima, the starting point of the energy storage state of the circuit breaker is detected. Then, the signal envelope sum is extracted as the feature vector by marking the obvious range of envelope amplitude difference through KS test, and the feature is filtered and dimensionally reduced by the releiff-sfs method to get the optimal feature subset. At last, the fuzzy c-means clustering (KFCM) is used to pre classify the features to obtain the optimal hyperplane with the least risk, and support vector machine (SVM) is used to establish the training model for state identification. The experimental results show that the energy storage state identification algorithm proposed in this paper only needs 0.2S to extract features on the premise of ensuring the accuracy, which is of great research value for on-line monitoring of circuit breakers.
Review of underwater sound absorption materials
Authors: Dong Jianzhu , Tian Pengyu
Published: July 2020

Underwater sound absorption is becoming more and more important for underwater military equipment. Underwater acoustic stealth technology is constantly developing, we have conducted a research, summary and classification of underwater sound stealth materials. There are mainly four kinds of underwater acoustic stealth materials: porous materials, resonance materials, piezoelectric materials and metamaterials. We also studied the sound stealth mechanism of these materials.
Analysis of the causes of the cracking of the tee joint of the header of the utility boiler
Authors: Xie Liming , Zhang Yanfei , Zhang Xuechao , Lv Lei
Published: July 2020

The butt joint of the high temperature superheater inlet tee of 330MW Unit Boiler in a thermal power plant cracked. The causes of the weld cracking were analyzed by means of macroscopic morphology observation, fracture SEM inspection, microstructure inspection, mechanical property inspection and chemical composition inspection. The results show that a large number of small thermal cracks are formed in the weld due to improper welding process or operation during boiler installation. At the same time, the improper post weld heat treatment of the joint results in the high hardness of the weld, the insufficient toughness reserve and the decrease of the crack growth resistance. During the long-term operation of the boiler, under the combined action of the primary stress caused by the medium pressure in the pipe and the secondary stress caused by the expansion and contraction of the pipe system, the small crystal cracks in the weld continue to expand, which eventually leads to the macro cracks.
Cause Analysis of Leakage in 316L Stainless Steel Heat Exchanger
Authors: Zhang Xuechao , Chen Hao , Zhang Tao , Sun Yunfei
Published: July 2020

A large area of leakage occurred in plate heat exchanger of a power plant. The causes of leakage were analyzed by means of appearance analysis, chemical composition analysis, microstructure detection and energy spectrum analysis. The results show that Cl ion exists in the environment of the leaking heat exchanger, which has strong corrosiveness to austenitic stainless steel. At the same time, there are machining residual stress and internal stress produced by internal medium in the heat exchanger, which lead to stress corrosion and cracking.
Improved accuracy optimal tuning method for hydropower units’ governor controller
Authors: Niasse Mouhamed , Zheng Qi , Xin Ai , Quan Federico Flamenco , Saleem Adeel , Iqbal Atif
Published: July 2020

This paper aims to improve the model of the hydro-turbine system under the effect of water-hammer for frequency-domain studies. It brings out a novel way to overcome the accuracy limitation linked to the simple first and second-order approximations of the gate-turbine transfer function. The proposed study is based on the detailed model of the hydraulic system considering the effects of water compressibility and pipe elasticity. The improved system is controlled using particle-swarm optimization algorithm, which is shown to be very efficient in controlling the overshoot and stability of the system connected to a single machine single load test system. Step response and load disturbance are simulated. Results from our example prove that covering accurately a frequency range from 0 to over 30Hz is easily made when using this method for frequency-domain simulations of hydropower plant load-frequency control.
Simulation study on anti-sliding performance of runway surface gathered water
Authors: Zhang Longsheng , Han Gensheng , Sun Mingzhi , Liu Zhaoxu
Published: July 2020

In order to study the anti-sliding performance of the aircraft on the runway especially for the surface gathered water condition, a finite element method is used to establish a finite element model considered the contact between aircraft tire and road surface. The vertical deformation of tire is analyzed and compared with empirical formula to verify the feasibility of the model. The adhesion coefficient is used as the anti-sliding evaluation index, and the influence of aircraft speed, tire load, tire pressure and water film thickness on the adhesion coefficient is analyzed by model. The specific conclusions are as follows: The adhesion coefficient between the tire and surface decreases with speed increases, increases with the tire load increases, and decreases with the tire pressure increases. The adhesion coefficient decreases with the increase of water film thickness, and when the water film thickness is thin, the adhesion coefficient decreases more obviously with the increase of velocity.
Influence of Vertical Prestressed Tensioning Process on Box Girder Web
Authors: Wang An , Zhang Xiaoyu , Liu Laijun
Published: July 2020

In order to study the effect of vertical prestressing tension timing and sequence on the vertical stress change of concrete box girder webs, an ANSYS finite element model was established with a large-span continuous rigid frame bridge to simulate the different tensioning sequence of the vertical prestressing steel strands. This paper analyzed the reasonable time of vertical prestressed tension, the stress variation of web plate under different ways of vertical prestressed tension, and the influence of secondary vertical prestressed tension on web crack resistance. The vertical compressive stress at the bottom of the adjacent beam section is obviously smaller than that at the middle of the beam section during segmental tensioning, which leads to the problem that the difference between the free end section and the vertical compressive stress at the end of the beam section is large. During the vertical prestressing of the two lagging sections, the vertical normal stress of the web is more uniform. The maximum vertical compressive stress is 2.7% larger than the overall tension, which is 32.3% less than the maximum vertical compressive stress of the segmented tension. In the case of vertical prestress loss in the initial tension, the reasonable use of the secondary tension construction process can significantly increase the cracking load of the beam.
Cause Analysis and Preventive Measures of Cavitation Corrosion of Diesel Engine Exhaust Valve Seat
Authors: Zhang Zhigang , Dong Qingfeng , Lu Jia , Gao Runyu , Yang Fan
Published: July 2020

This paper analyses the formation of cavitation in the exhaust valve seat of marine diesel engine in combination with leakage of the exhaust valve seat. The paper mainly starts from the cooling water system of the diesel engine that affects cavitation. Finally, the paper puts forward some preventive measures of cavitation corrosion.
Properties of modified epoxy matrix composites reinforced by glass fiber
Authors: Chen Jian , Hang Yuwen
Published: July 2020

The glass fiber reinforced epoxy resin matrix composites were prepared by press molding. Experiments show that the bending strength and flexural modulus of the composite are increased by 16.2% and 21.2%, and the interlaminar shear strength is increased by 28%. The fibers of modified resin matrix composites were uniformly arranged and adhesion of the interface was decent through the scanning electron microscope.
Analysis of display whitish problem on a certain reinforced integrated computer
Authors: Zhang Bin , Li Chao
Published: July 2020

Aiming at the problem that the color of the display screen of a certain type of rugged integrated computer is white, the analysis and location are carried out first. By assuming a method to eliminate the problems of the main board, wiring harness and the display itself, the positioning fault exists with the LCD panel. After the test, it was found that the faulty plate was caused by the high contrast of the display control board. After a detailed analysis, the results showed that the connection of low-resistance media caused a short circuit between pins 1 and 3 in interface CN603, which had the same effect as pressing the contrast adjustment shortcut button S1. The contrast of the display control board is continuously increased, so that the display becomes white. The research in this paper enriches the cases of solving practical problems in engineering applications, and provides theoretical support and reference basis for the subsequent solving of similar problems.
Model and dynamic performance analysis of mountain tractor suspension implements
Authors: Yang Hongtu , Xia Changgao , Han Jiangyi , Chen Chen , Zhang Hongdang
Published: July 2020

A tractor three degree of freedom of agricultural implement suspension mechanism is proposed. The position and posture of the agricultural suspension implement frames are controlled by adjusting these three active motion pairs. Since the agricultural suspension implement is fixed on the mountain tractor through three points, the adjustment of the agricultural implement position and posture is obtained. Corresponding dynamic performance analysis of the mountain tractor suspension implements is analyzed. This model can be used for the operation of the tractor and farm implement set with automatic chassis levelling on the slope. The farm implement and the slope terrain can be profiled by adjusting the position and posture of the farm implement, and the lateral uniformity of the cultivation depth can be improved.
A study on natural rubber composites reinforced by carbon fiber
Authors: Zhang Qiong , Li Yi , Zhu Pengxiao , Yuan Song
Published: July 2020

The carbon fiber was used to reinforce the natural rubber. The mechanical property, thermal property, morphology and thermal conducting property of the rubber composites were researched. The carbon fiber is dispersed well in the rubber matrix according to the scanning electron microscope images. The strength increased with the increase of the carbon fiber content and the strength reached the maximum value 20.9MPa when the content of carbon fiber is 2%. The addition of carbon fiber improves the aging resistance of rubber and maintain the property of rubber matrix. The addition of carbon fiber can improve the decomposition temperature effectively and enhance the heat-conducting property.
Analysis and control of ventilation noise reduction for box-type transformer in urban area
Authors: Wu Fayuan , Chen Yaqiong , Liu Xiaolei , Tang Jinhui
Published: July 2020

Noise generated by outdoor box transformer in the working process has a certain impact on the production and life of the surrounding residents. Combining with the current situation of box transformer in 10kV urban area of a residential district, the paper analyses the problems and causes of noise transmission and control. According to the characteristics of noise sources and transmission ways of substation, the paper puts forward and implements ventilation, heat dissipation and sound insulation cover to reduce noise, improve room temperature and ventilation effect, and compares and compares them. The effect of noise control before and after modification is analyzed. The result shows that the effect of modification is obvious and the noise at boundary of box transformer meets the national standard.
Research on magnetic field size and coil parameters based on non-contact magnetic induction detection of corroded rebars in infrastructure
Authors: Xiong Jingsong , Chen Chuan , Ye Huarui , Gan Pengfei
Published: July 2020

Non-contact magnetic induction detection is widely used in infrastructure testing due to its advantages. How to choose the appropriate magnetic field and the corresponding coil parameters is very important for electromagnetic detection. Excessive magnetic field causes excessive coil power consumption, which leads to serious heating and affects the service life of the equipment; however, if the magnetic field is too small, the detection accuracy will be reduced due to the attenuation of the magnetic field. This paper first analyzes the principle of magnetic induction detection, then the simulation analysis is carried out based on the buried depth and type of rebar commonly used in infrastructure to choose the appropriate magnetic field size.
Troubleshooting and Fault Analysis of Initial Built-In Test Interruption of Civil Aircraft Primary Flight Control System
Authors: Liu Wenwen
Published: July 2020

Currently, there are no flight control alarms or CMS fault information triggered when initial Built-In Test is interrupted for primary flight control system, in fact, only “TEST ABORTED” displayed for the “TEST STATUS” on the CMS, which brings some difficulties to the Built-In Test interruption troubleshooting. A Built-In Test interrupt troubleshooting methodology is proposed in this paper based on fault tree analysis.
Analysis on the cause of crack in connection pipeline of subcritical boiler reheater
Authors: Zhang Yanfei , Yun Feng , Fang Wenxuan , Wang Haixue
Published: July 2020

Several coal-fired thermal power boilers with the same sub-critical parameters in Mengxi area of Inner Mongolia have successively suffered from cracking and leakage failure events of reheater connecting pipes, most of which occur at chamfered back tool grooves on the inner wall grooves of pipe welding joints. In order to find out the cause of cracking, typical failure samples were intercepted for macro-morphology, microscopy, SEM, chemical composition, mechanical properties, wall thickness measurement analysis and design and operation data investigation of several boiler equipment. The results show that comprehensive factors such as deviation of burning coal type from design of boiler, automatic dispatching of AGC load in power grid, low nitrogen combustion modification and so on cause changes in boiler combustion conditions and operation, which results in excessive high input level of reheater cooling water, resulting in long-term alternating thermal stress and non-periodic vibration of straight pipe and elbow arranged after fine-tuning of refrigerant flow direction in reheater. Finally, thermal fatigue cracks are induced to initiate and propagate through the stress concentration area of the chamfered knife groove of the inner wall of pipe welded joints.
Design and Engineering Test of Soil Filling Pile with Spiral Cone Foundation
Authors: Fang Ming , Fang Guangxiu , Zhao Shifan , Liu Shoujin
Published: July 2020

In this paper, through the comparative analysis of two different types of pile foundations, long auger bored cast-with-pressure concrete pile and Soil filling pile with spiral cone at the same engineering project and the same geological conditions in Western Liaoning Province, it is concluded that the soil filling pile with spiral cone compare with the long auger bored cast-with-pressure concrete pile, have obvious technical advantages in construction period and guarantee, reduce the construction expenditure. Moreover, the pile integrity testing is good, and has achieved good economic and social benefits. It is a new type of energy-saving and emission-reducing pile foundation with wide application prospects.
Application of Instrumental in the Identification of Solid Waste Characteristic of Imported recycled ABS Plastic
Authors: Luo Chuan , Wang Hao , Wang Qian , Liu Zhihong , Yuan Lifeng , Zhang Chao , Lin Zhenxing
Published: July 2020

The content of carbon, hydrogen and nitrogen in imported recycled ABS plastics was determined by Instrumental, and the content of three monomer units (acrylonitrile, butadiene and styrene) in ABS was calculated. The influence of sample quantity and combustion time was discussed. The precision of carbon, hydrogen and nitrogen was 0.08% - 1. 32%, and the content of three monomer units was 0.08% - 1.32%. The precision of the method was 0.72% - 8.22%, and the recovery rate of the method was 90.7% - 114.8%. The precision and recovery rate of the method are good. It can quickly determine the content of each monomer unit in ABS plastics, and provide technical support for the property identification of related imported plastic solid waste.
Research Background and Mechanism of Soil Filling Pile with Spiral Cone Technology
Authors: Fang Ming , Fang Guangxiu , Zhao Shifan , Liu Shoujin
Published: July 2020

This paper introduces the research background of soil filling pile with spiral cone technology. It is a new type of energy-saving and emission-reducing construction pile foundation design and construction technology. The foundation pile is a kind of soil filling pile with spiral cone which has the technical advantages of rotating extrusion cast-in-situ pile and bidirectional short spiral extrusion soil pile. At the same time, the mechanism is expounded. The soil compaction of the bit and the secondary diameter-retaining drill pipe is sufficient, the penetrating force is strong, and the geological conditions are widely adapted. The effect of the rock and soil around the pile on the pile is fully improved, thus the bearing capacity of the pile is increased and the construction cost is reduced. When calculating the vertical ultimate bearing capacity of a single pile, the value of the correction factor for the increase of the same rock and soil layer around the pile increases gradually from the soil displacement screw pile, rotating extrusion cast-in-situ pile and soil filling pile with spiral cone, and the vertical ultimate bearing capacity of the three piles increases sequentially.
Design of Beidou timing module
Authors: Sun Quanyu
Published: July 2020

The Beidou timing module receives the Beidou Satellite Information, calculates the time and positioning information, transmits the time and timing information through various external interfaces, and has the function of short message forwarding. This paper presents a system design scheme for the Beidou time-keeping module, which uses adaptive filter switching technology to achieve accurate and stable time-keeping results, by automatically switching synchronous clock source (Beidou, IRIG-B (DC), internal high-stability crystal Oscillator) to complete time service, Beidou module with seamless switching, short-circuit protection, fault detection and diagnosis, health management and other functions.
Experimental and Automatic Measurement System Design of Flatness of Automatic Wallboard Cutting Surface
Authors: Zhao Honghua , Han Qifei , Zhao Jian , Lin Yifei , Gong Xuyin , Hu Zhitong
Published: July 2020

With the development of the industrialization of buildings, the demand for wallboard is increasing. The development of wallboard automatic production lines can solve the problems of low efficiency and low automation in the production process of wallboard. In the paper, the insufficient of the method that wall panel length detection in JGT169-2016 is considered, the automatic measurement system and cutting surface flatness analysis experiment is designed. Using MATLAB to filter and fit data. Optimize the cutting speed of wallboard based on LJQB-JX-600-QGJ.01 cutting machine. Through experimental analysis, better control parameters are selected for production control, and the quality of production wallboard is further improved, thereby improving the quality of the production line.
Application of Fusion sample preparation X Ray Fluorescence Spectrometry in the Identification of Solid Waste Characteristic of Imported Coated Fibre Cloth
Authors: Luo Chuan , Wang Qian , Liu Zhihong , Wang Hao , Chen Tieshan , Lin Zhenxing
Published: July 2020

The composition of imported coated fibre cloth was quickly identified by fusion sample preparation X-ray fluorescence spectrometry. Na2O, MgO, Al2O3, SiO2, P2O5, SO3, K2O, CaO, TiO2, Cr2O3, MnO, Fe2O3, NiO, CuO, ZnO, As2O3, SrO, ZrO, CdO, BaO, PbO in the matrix of the coated fibre cloth were determined. In this paper, the technology of direct melting of flake sample is studied. The method of pre-oxidation is that the sample piece is obliquely placed on the inner wall of crucible to increase the air circulation space and remove the organic matter and halide in a short time. The 66.5:33.5 mixed flux was used as the flux, and LiBr was used as the release agent. The temperature was about 1050 °C, and the time was about 17 min. The problem of melting of inorganic fibre and flux melt was found and solved. The calibration curve is constructed by silicate rock, bauxite, cement and other reference materials and high-purity reagents. The matrix effect correction adopts the variable theoretical α influence coefficient method, and B2O3 represents the unmeasured components as the elimination item. The maximum Al2O3, SiO2, CaO curves of this method are 84.4%, 91.5%, 62.6%, respectively. The Cr, Ni, Cu, As, Cd, Pb curve range of harmful elements is greater than 0.005%-0.33%; 21 curves have good linearity. R2 divided by BaO equals 0.997 and the rest are greater than 0.9993; the detection limit of harmful elements is less than 15 mg·g−1; precision relative standard deviation (n=11) principal component is less than 0.5%, and trace component is less than 15%; after comparison of standard substances and standard methods, the results are consistent. Accuracy of methods is good, and it can quickly identify the content of the main elements of the coated fibre cloth and provide a strong support for the subsequent identification of solid waste characteristic.
Study on fatigue crack growth rate of 15CrMo steel based on stress ratio and corrosion environment
Authors: Wang Jing , Guo Chong , Huang Kuichao , Shao Xiaolin
Published: July 2020

In this paper, the fatigue crack growth rate of 15CrMo steel, a typical gas cylinder material, is studied under the condition of simulating the actual working condition of gas cylinder. The low-frequency corrosion fatigue tests with stress ratio of 0.1 and 0.5 are carried out in air and different concentrations of wet hydrogen sulfide environment. The relationships between da/dN and ΔK are expressed by Paris equation. The results show that the crack growth rate in hydrogen sulfide environment with concentration of 200 ppm is 27 times higher that in air. The addition of corrosion environment greatly fasts the crack growth rate of 15CrMo steel. With the increase of H2S concentration, the crack growth rate increases exponentially. With the increase of stress ratio, the average stress increases, the crack closure effect decreases, the crack tip is fully opened, and the contact area with corrosion medium increases, which results in the increase of crack growth rate.
Asphalt Pavement Stress Intensity Analysis under Fluctuating Load
Authors: Gao Jianhong
Published: July 2020

The finite element software ANSYS is used to build the asphalt pavement three-dimensional model and to carry through transient analysis. The stress intensity time-history curves of asphalt pavement under the fluctuating load are obtained. The curves reveal that the pavement structure stress intensity effect of dynamic load is complex. And the point stress intensity always reaches its peak value when the load reaches this point. After the load leaves, it decreases rapidly to zero. Pavement surface is most significantly affected by load. The deeper the pavement surface is, the smaller the impact is, but the influence law remains unchanged. These conclusions can provide reference for stress intensity condition of asphalt pavement under fluctuating load.
Synthesis and Photophysical Properties of Bromination the Small-Molecule Acceptor for Organic Solar Cells
Authors: Jiang Zhao , Mao Wei-Wen , Wang Jin-Liang
Published: July 2020

At present, the modification of the benzene ring based terminal group IC is widely studied and a series of progress has been made. Our work designed and synthesized a new brominated fused ring small molecule receptorFBDTEH-2Brby introducing bromine atoms into terminal group. On the one hand, the electron-withdrawing effect of bromine enhances the push-pull electron effect between the core electron-donating segment and the end-capping group, making the absorption spectrum ofFBDTEH-2Brmore suitable. It shows broad absorption in the range of 600–800 nm in solution, the maximum absorption peak ofFBDTEH-2Brin solution is 742nm, While for the thin film, the absorption extended broader with an obvious red-shift in the range of 800–900 nm, it is beneficial to higher JSC. The maximum absorption peak is 800nm in the film, which can be explained by it’s nearly planar structure and the good intermolecular π-π stacking in the solid state caused by the dibromide IC. On the other hand, the introduction of Br atoms will also enhance the intermolecular interactions and improve the electron mobility. The optical band gap ofFBDTEH-2Bris 1.43 eV. These results demonstrated that due to the bromine atom has a larger size, the end groups of adjacent molecules still exhibit strong interactions with short π-π distance Because of the O···S and Br···S interactions, which is beneficial for the charge to transport along multidirections. Therefore, the introduction of bromine atoms into theterminal group to design and synthesize new brominated small molecule acceptors is expected to obtain better performance in organic solar cell materials.
General Situation of Solid Lubricant Coatings
Authors: Qin Ke , Feng Qing , Li Haoming , Zou Shuai , Dou Mingyuan , Huang Fuchuan
Published: July 2020

Lubricant is one of the important supporting materials in modern industry and national defense industry. The purpose of using lubricant is to reduce friction and wear, reduce or avoid material damage. Lubricating oil and grease are traditional lubricating materials, but they have their own application limitations. Solid lubricating materials, especially their lubricating coating, can meet high temperature, high pressure, high vacuum and other harsh conditions, and they are more and more widely used in various industries. Based on a large number of literatures at home and abroad, the properties, application characteristics and preparation technology of solid lubricant coating are reviewed, and the research trend of solid lubricant coating is prospected.
Fracture failure analysis of coal mill shaft
Authors: Lyu Lei , Zhang Tao , Sun Zengwei , Sun Yunfei
Published: July 2020

During the operation of No.2 boiler in a power plant, the fracture of a coal mill shaft occurred. The fracture causes of the coal mill shaft were found by macroscopic inspection, metallographic inspection, chemical composition analysis, fracture morphology analysis and mechanical property inspection. The experimental results showed that: 1. The external surface of the coal mill shaft had been welded, and the poor welding process resulted in a large number of welding defects such as cracks, slag inclusions and lack of fusion in the overlaying layer; 2. The improper hot working process of the coal mill shaft resulted in the abnormal metallographic structure of the shaft, and the existence of serious reticulated ferrite and brittle widmanstatten structure resulted in the low strength of the shaft. 3.Because of the existence of the cyclic torsion and bending stress of large load, the initial crack source occurred at the welding position of the hardfacing layer, and then extended in the form of fatigue, eventually causing the coal mill shaft to break. Three factors led the high cycle and low stress fatigue fracture of the coal mill shaft.
Field experimental study on the dynamic response of CRTS-I ballastless track subgrade of the Shanghai-Nanjing intercity high-speed railway during operation period
Authors: Liu Ting , Pei Yanfei , Su Qian
Published: July 2020

Shanghai-Nanjing intercity high-speed railway, the busiest high-speed rail in China, built with the highest standards, the longest mileages, and the fastest speed among the world. Having been in operation for 5 years, it is important to figure out the performance and rules of dynamic characteristics evolution of the substructure. To study the vibration characteristics of the ballastless track subgrade after a few years of operation, in-situ train-induced tests were carried out in Shanghai-Nanjing intercity railway representative subgrade sections. The value of vertical vibration acceleration, displacement and velocity of different measuring points in both end and center of track slab under the train load is acquired, and distribution regularities of dynamic response for ballastless track subgrade on the period of operation are summarized. The results show that: At the end of track slab, the vibration acceleration value in each layer of the ballastless track subgrade structure decays dramatically in the vertical direction, which appears an exponential trend; while in the center, the vibration acceleration value decays gently in vertical direction, which appears a roughly linear trend. On the position of subgrade surface and road shoulder, vibration acceleration values are closer in both end and center of track slab; The special parts of the end of track slab mainly have an amplification effect on vibration response of the track slab and concrete roadbed, and the train’s speed is considered to have the most notable amplification effect on the vibration acceleration of the end of track slab. The vibration displacements of the track slab and the concrete roadbed show a linear relationship with the variation of the train’s velocity, while this trend is not remarkable on the position of subgrade surface and road shoulder, which is in accordance with the dynamic displacement distribution measured among inner part of the subgrade of high speed railways such as Beijing-Tianjin, Wuhan-Guangzhou, Zhengzhou-Xi’an.
Influence of Girder Spacing on Vortex-Induced Vibration Performance and Flow Field Characteristics of Double-Layer Box Girder
Authors: Huo Wuxing , Gong Ming , Tang Xiao , Zhang Yao
Published: July 2020

Through wind tunnel tests and computational fluid dynamics (CFD), the vortex vibration performance and flow field characteristics of double-layer box girder with different girder spacings were studied. The results showed that the double-layer box girder has vortex-induced vibration phenomena at 0 ° and positive wind angle of attack. Among them, at 0 ° wind angle of attack, the double-layer box girder’s vortex performance gradually became better with increasing girder spacing. Under the wind attack angles of +3° and +5°, the vertical bending vortex vibration performance of the double-layer box girder showed a trend of first optimizing and then worsening with the increase of the girder spacing, and the torsional vortex vibration performance of the double-layer box girder showed a tendency to deteriorate first and then improve with the increase of the girder spacing. The development of vortices caused by the enhancement of the flow separation between the upper surface of the upper girder and the lower surface of the lower girder caused by the aerodynamic interference between the upper and lower girders of the double-layer box girder, and the magnifying effect of the upper girder on the vortex in the wake area of the upper surface of the lower girder were the internal reasons for the influence of the girder spacing on the vortex vibration performance of the double-layer box girder.
Welding Deformation of Unequal Thickness Tailor Welded Blanks under Multiple Factors
Authors: Meng Dawei , Zhang Liping , Li Yan , Zhang Guizhi
Published: July 2020

With the popularity of lightweight requirements, the application of tailor welded blanks with unequal thickness is increasing gradually. The welding deformation of tailor welded blanks with unequal thickness inclined weld is affected by the external constraints and the internal structural parameters of the plates. In this paper, the effect of the external constraints and the internal structural parameters on the multi-layer and multi-pass welding deformation of unequal thickness inclined weld was investigated. The deformation distribution law of butt welding of unequal thickness inclined weld was obtained combined with simulation and experiment results. The results showed that the spring constraint method was similar to the actual welding condition, meanwhile, the control effect of spring constraint on the welding deformation was better. The welding gap had the greatest influence on the welding deformation, followed by the angle of inclined weld, thickness of thick plate and thickness of thin plate. When the thickness difference between two plates was kept at 50%, the control effect of welding deformation was the best.
Analysis of Operation Rule of Check Valve in High Pressure Tubing Based on Improved Euler Method
Authors: Zhao Xiaolei
Published: July 2020

When the fuel injection nozzle of the engine works, the actual fuel injection quantity will change due to the pressure change of the high-pressure fuel pipe, which will affect the working efficiency of the engine. Therefore, it is necessary to adjust the operation rule of the check valve in the high-pressure fuel pipe so that the pressure is relatively stable at a certain value, the working process of the engine is more reasonable, and the engine loss is reduced. In this paper, the recursive formula of the mathematical model of the check valve and the high-pressure tubing is established, and the improved Euler method is used to solve the problem. It simulates its working condition at stable pressure and pressurization at different speeds, and then analyzes the reasonable operating cycle of the check valve accordingly, so that the pressure in the high-pressure fuel pipe meets the requirements.
Single Parameter Engine Analysis and Performance Optimization of a Medium Duty Gasoline Engine
Authors: Hushim Mohd Faisal , Noranai Zamri , Yan How Daniel Lau , Ikhsan Zainul Abidin Zainul Ameerul , Razali Mohd Azahari , Sapit Azwan , Mohamed Akmal Nizam
Published: July 2020

This paper examines various attempts to impose a single parameter analysis on the effect of intake valve opening (IVO) timings and intake runner length (IRL) technologies on the engine performance output at full load condition through an engine model representing 1.6 liter in-line 4 cylinders, 4-stroke SI engine constructed using GT-Power simulation software which is then simulated and correlated to the CAMPRO 1.6L model constructed previously with an updated crank train geometry such as cylinder stroke length and the connecting-rod length (con-rod) where comparison results of Volumetric Efficiency (VE), Brake Power (BP-kW), Brake Torque (BT-Nm) are carried out to maintain the accuracy and validity of the model to be used. This model is then used to simulate the engine performance under different sets of intake runner length (IRL) and difference sets of intake valve opening (IVO) timings. The various sets of IRL and IVO are then configured to correspond with each other to predict the most suitable optimization setups at targeted engine speeds, ranging from 2000-4000 RPM in this research to eliminate the existence of performance dip for better cycle efficiency. Results shown significant improvement through the different IVO timings and different IRL setups, as compared to the stock settings
Study on Behavior of Water Treatment Pump Before and After Modification using Finite Element Modal Analysis
Authors: Bin Fasal Mohamed Mohamed Firdous , Bin Azmir Nor Azali
Published: July 2020

The aim of this study is to conduct a finite element analysis towards an existing water treatment pump and modification in order to reduce resonance. The application of water treatment pump is a way to inhale dirty water from the lower pressure to the high pressure area. Improvement and study about water treatment pump system to reducing the resonance with several modifications on the pump structure. Therefore, the pump will be designed to meet the requirement of the system. The basic concepts of available water treatment pumps were studied thoroughly. Designing with the actual measurements, the next step was to analyze the design using Finite Element Analysis (FEA) for simulations of natural frequency, static and dynamic analysis via Solidworks2017. It is to make sure that the system can function without any failure and to determine the vibration level due to resonance phenomenon. Result for modal analysis shows that the excitation frequency which experienced by the pump casing is 47.57 Hz and the natural frequencies are above 500 Hz which is too high. After adding damping system to the pump casing, the natural frequency reduced to 6.9286Hz, 20.254 Hz, 9.477 Hz, 46.29 Hz and 71.819 Hz which in turn reduces the vibration. For rotary screw, natural frequencies were reduced when the material stiffness has been decreased from 74,000 N/m2 to 72,400 N/m2.
Development and Characterization of Injection Moulding Mould for Ulna Implant
Authors: Kamarudin N.H. , Ibrahim M.H.I. , Mahzan@Mohd Zin S. , Othman M.H. , Amin A.M.
Published: July 2020

Metal injection moulding is a method by which metal parts are produced near net form by using metal feedstock. Current medical implants are products that must meet rigorous material, technology and functionality specifications. Corrosion resistance, bio-compatibility, bio-adhesion, bio-functionality and accessibility are the main medical desires of all medical implants. This work focused on the design and production of ulna plate implants using metal injection moulding. To be details on this, maximum stress and shrinkage of ulna implant components are studied. The size after demoulded from cavity was measured and compare to the cavity size. The range of shrinkage is observed by weights lost after debinding process that the result shows 0.1 gram decreased. The average maximum stress is 5.2749 MPa. Based on the result, the products are brittle after debinding process.
Investigation on the Performance of a Novel Dehumidifier for a Combined Solar Chimney and Liquid Desiccant Plant
Authors: Ang C Y , Alimin A J , Mahal S K
Published: July 2020

A dehumidifier was one of the main component in the hybrid liquid desiccant system and solar chimney micro-plant. The performance of the hybrid liquid desiccant system and solar chimney micro-plant was strongly depended on the performance of it dehumidifier, but it is yet to be analyzed in any of the previous studies. Therefore, moisture removal rate (MRR) and dehumidification effectiveness (ε) were two parameters that had been chosen to evaluate the performance of the cross flow, cellulose panel structured bed dehumidifier in this study. Calcium Chloride (CaCl2) desiccant solution was the only liquid desiccant solution used in this application. From the experiment, it was found that the highest effectiveness of the dehumidifier was about 22.78% and the highest moisture removal rate was about 0.22ml/s. Besides that, parametric analysis had been conducted on five inlet parameters: desiccant inlet concentration, desiccant inlet temperature, inlet air humidity ratio, inlet air mass flow rate and inlet air temperature; the most influencing parameter was found to be the inlet air humidity ratio, ya1. MRR increased by 52.68% and ε of the dehumidifier increased by 48.59% when ya1 increased from 0.0175-0.0200. Finally, three improvement strategies had been recommended: increasing the concentration of liquid desiccant, changing the type of liquid desiccant and increasing the thickness of the dehumidifier.
Production of disposable takeaway food container from areca leaf sheath (ALS) as sustainable packaging material
Authors: Jong Oi Ka , Yong Tze Mi , Jaafar Muharam Rafidi
Published: July 2020

Areca leaf sheath has been used traditionally to produce disposable plates and bowls in India for decades. This project aims to produce disposable takeaway food containers by using the fallen Areca leaf sheath. In order to achieve the aim, a press mold is self-designed and fabricated, and installed into a disposable paper plate press machine to form the sheath into container shape. The density of the sheath is 0.423 g.cm−3 and 0.391 g.cm−3 before and after press respectively. The moisture content percentage obtained before heat press is 19.19%, while after press is 5.01%. The sheath at its sheath line direction shows higher stiffness, which is 416.9g.cm, compared to the perpendicular sheath direction of 65.1g.cm. The sheath has a water absorption rate of 0.021g.min−1, which fulfils the purpose of disposable food packaging to contain foods with soup or sauce.
Dynamic Weighted Idle Time Heuristic for Flowshop Scheduling
Authors: Zainudin A.S. , Bareduan S.A. , Isa N.A.
Published: July 2020

Flowshop scheduling is used to determine the optimal sequence of n jobs to be processed on m machines in the same order. The objective of this paper is to minimize the makespan for group of jobs waiting in the process system. It proposed a new heuristic that apply dynamic weighted idle time (DWIT) that used several weight factor values as a multiplication factor of the total idle time. The result shows that the average percentage errors and standard deviation for DWIT heuristic are smaller compared to the NEH (Nawaz, Enscore and Ham) and it achieved more than 50% of optimum answer. Therefore, this DWIT heuristic has great potential to outperform the NEH heuristic.
Sonication-Assisted Pine Cone Flower Cellulose Hydrolysis Using Formic Acid
Authors: Zakiyya ‘Urfa , ‘Uyunin  , Masruri Masruri , Ningsih Zubaidah , Srihardyastutie Arie
Published: July 2020

Nanocellulose has many applications in industrial sectors, such as in pulp and papermaking, production of synthetic textile fibers, dye, ink, and coating materials. The cellulose itself can be isolated from the waste of pine cone flower. This paper reports formic acid in the different concentrations (10%, 30%, and 60%) for hydrolyzing of cellulose using sonication technique (48 kHz) at 45 °C for 60 mins. The hydrolyzed cellulose was analyzed using FTIR and XRD spectrometry. It was found that the hydrolyzed-cellulose isolated was 92.4%, 94.6%, and 89.6%, respectively. The FTIR spectra provided the band for O-H (3435 cm−1) and C-O-C (1180-1060 cm−1) functional groups. However, the spectra also showed the C=C band for lignin impurities at 1661 cm−1. Furthermore, The XRD data gave similar 2-theta values for all hydrolyzed cellulose at 16°, 22°, and 34° respectively. The crystallite size was 18.34, 15.09, and 15.07 nm. Meanwhile, the crystallinity index was 50.50, 52.70, and 51.60% respectively.
The potency of Polylathia longifolia from Indonesia and the Philippines as therapeutic agents on inflammatory bowel disease (IBD) in Rats (Rattus norvegicus) induced by Indomethacin
Authors: Aulanni’am A , Anita T Z , Nahari D S , Aluka I A , Agustine E I , Novita T , Pentaloka A A , Wuragil D K , Riawan W , Beltran M A G
Published: July 2020

Herbal medicines have the potential to be used as therapeutic agents. Polyalthia longifolia is widely grown in both Indonesia and the Philippines, but it has not commonly used for its therapeutic purposes. Some studies reported that P. longifolia leaves extract has anti-inflammatory activity. In this study, the potential of Polyalthia longifolia leaves extracts for inflammatory bowel disease (IBD) in Indometachin-induced rats was tested. Four groups of rats were used for this research, were control (T1), rats with IBD with 10 mg/kg BW of sulfasalazine therapy (T2),) rats with IBD treated with 300 mg/kg BW of Indonesia P. longifolia leaves extract therapy (T3) and rats IBD treated with 300mg/kg BW of The Philippines P. longifolia leaves extract therapy (T4). Histopathology of gastric, duodenum, jejunum, and colon were analyzed, with protein profile and pro-inflammatory cytokines expressions. The results showed that P. longifolia leaves extract therapy origin from Indonesia and the Philippines were potent as anti-inflammatory agents comparable to commercially available drugs against IBD. This works proposed the use of P. longifolia leaves as IBD therapy.
A molecular docking study of dehydroevodiamine as an inhibitor of epstein-barr virus protease
Authors: Azizah R N , Suharti  , Yahmin
Published: July 2020

Epstein-Barr Virus (EBV) is a type of γ-herpes virus which cause kissing disease. The virus induces cancer and causes latent infection. EBV protease is one of the constituent capsid proteins that play an important role in assembling virions on nucleus and spreading them. Therefore, this enzyme potentially became one of inhibition target which have impact on the termination EBV life cycle. During this time, drugs to inhibit this enzyme had not been studied. This study aimed to examine dehydroevodiamine as a potential inhibitor EBV protease by molecular docking method. The docking was done through both blind and specific docking techniques and the Ki values were calculated using docking approach when RMSD is 0 Å. Molecule visualization was done using PyMol and dehydroevodiamine profile identification was done on Ro5. The results showed that dehydroevodiamine has binding affinity of -9.8 kcal/mol and -7.3 kcal/mol; predicted Ki (STP) of 1,426729x10−8 and 1,431479x10−6 for blind and specific docking, respectively. Dehydroevodiamine profiles does not violate Ro5. These values indicated the potential of dehydroevodiamine as an oral drug candidate for kissing disease. This finding opens possibility to do further work on wet-lab-levels.
The Effect of CMC, Agar, and Konjac on the Characteristics of Durian Seed Starch Edible Film
Authors: Haekal Muhammad Husain , Mawarani Lizda Johar
Published: July 2020

Edible film as synthetic plastic food wrap alternatives continuously developed. Durian seed starch is one of the materials used on edible film fabrication. This research studied on durian seed starch-based edible film with the addition of carboxymethyl cellulose (CMC), agar, and konjac with a mass fraction of 10%, 20%, 30%. The observed characteristics were swelling degree and tensile strength of the fabricated film. The edible film solution was made using ratio of flour and additives, water, and glycerol of 1:20:0.3 (w/w), stirred for 20 minutes at 70°C. The results showed that agar addition on edible film made the film could not be fabricated, konjac addition increases the swelling degree and the tensile strength, while CMC addition increases the swelling degree and decreases the tensile strength. Agar and CMC are not compatible to be the additive on the durian seed starch edible film. The most optimal results were with the addition of 30% of konjac with the tensile strength of 9.4 MPa and swelling degree of 1073.81%