Applied Mechanics and Materials
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2022 ◽  
Vol 904 ◽  
pp. 1-5
Author(s):  
Jiang Ling Tang ◽  
Xing Jian Zhu

The output power of Direct Methanol Fuel Cells (DMFC) is one of the most important elements which limit the performance of DMFC. In order to enhance performance of DMFC, it is necessary to have model to modeling the output power of DMFC. In this paper, a novel model base on Support Vector Regression (SVR) to modeling the output power of DMFC base on output current (I) and operating temperature (T). The test result is shown that the generalization ability of SVR model is high accuracy. This investigation suggests that SVR is quite satisfied used to developing a DMFC model and can be used for controlling, optimal designing and feasibility study of the DMFC system.


2022 ◽  
Vol 904 ◽  
pp. 17-25
Author(s):  
Bo Hao Xu ◽  
Shuai Wang ◽  
Kai Fa Zhou ◽  
Wen Yi Ma ◽  
Nan Sun

There exist some problems in the crash box and anti-collision beam sandwich structure, such as monotone deformation pattern and uneconomical energy absorption performance. In order to raise the deformation capacity and energy absorption performance of sandwich structure, centrosymmetric reentrant honeycomb (CRH) and hexagonal centrosymmetric reentrant honeycomb (HCRH) are proposed based on auxetic reentrant honeycomb (ARH) in this work. Based on HCRH, four kinds of transverse combination structures and two kinds of longitudinal combination structures are obtained. The results of specific energy absorption show that the energy absorption capacity of the angular contact homodromous combination structure (ACOC) is about 3 times that of the other three transverse combination structures. Compared with longitudinal heterodromous combination structure (LHEC), the energy absorption capacity of longitudinal homodromous combination structure (LHOC) is improved by 72.7%.


2022 ◽  
Vol 904 ◽  
pp. 27-33
Author(s):  
A.V. Sedelnikov ◽  
V.V. Serdakova

The author of this scientific paper studies the stress-strain state of the solar panel of a small spacecraft after a temperature shock. The temperature shock is caused by the entry or exit of a small spacecraft into or out the Earth's shadow. In this work is considered a one-dimensional model of thermal conductivity. It is assumed that the solar radiation flux falls properly on the solar panel. Violation of normality due to deformations is neglected. A special feature of this work is to take into account the actual fixing of the solar panel. The boundary conditions in the form of a seal are preserved. However, the mobility of the smallest spacecraft is taken into account as a result of the occurrence of a longitudinal force in the solar panel during a temperature shock. The results are compared with the simulation data without taking into account the mobility of the small spacecraft. The results of this work can be used in the design of small spacecraft for technological purposes to meet the requirements for microaccelerations.


2022 ◽  
Vol 904 ◽  
pp. 7-15
Author(s):  
Salah Hamed Ramadan Ali ◽  
Gehan A. Ebrahim

Coordinate technologies play an important role in many industrial applications, especially for eco nanobuildings and spaces. Lately, the global new architecture seems to be more automated as appeared in the parametric architecture, topological, animate, metamorphic, and isomorphic and per formative architecture. They all depend on the visualization, the high precision techniques, and the 4th dimension all within sustainability. But till now, there is no main environmental space code, unit or standards to deal with to insure that the environmental design became in a form of an easier one to be the design of the era as all the global calls aware us to preserve the nature from pollution. Mainly within the call for the nanotechnology, if there is found a least architectural volumetric unit which can fulfill all the environmental sustainable systems within the visionary and the 4th dimensional acts, then we can act with the environment with easier spaces that can be duplicated in a uniform way, to work easily for measure and estimate the budget of his supposed built space. Therefore, the main liable issue concerns the research for the least architectural volumetric unit, and we can call it the nanoarchitectural unit. As nanoarchitecture is a virtual and proposed kind of architecture, which the architects aim to create it or follow it the nanotechnology to insure that the 3D technology is to submit as an application in all branches of science, to achieve a dream of the present-day from sustainability and environment for future generations. Accordingly, recent studies have confirmed that 3D coordinate technology using digital printing has an important subtle impact on industry, especially for green buildings and spaces.


2022 ◽  
Vol 904 ◽  
pp. 51-55
Author(s):  
Jun Yan Ding ◽  
Cui Xiang Jiang

In order to study the influence of the splitter plate in the elastic support system, the SST k-omega turbulence model is used to solve the problem, and the cylindrical system with splitter plate is numerically simulated by overset mesh. This paper studies the effect of the splitter plate on the vibration system at different deflection angles. The results show that the splitter plate has little effect on the system when the deflection angle is low. When the deflection angle is about 10 degrees, the system vibration characteristics will have a sudden change, the amplitude will decrease, and the vortex frequency will increase. Between the deflection angle of 10 degrees and 45 degrees, as the deflection angle increases, the amplitude increases and the vortex frequency decreases. It can be seen from the motion trajectory that the deflection angle changes suddenly after 10 degrees, and the system has a very small amplitude between 10 degrees and 25 degrees. In this declination interval, the splitter plate controls the vibration of the cylindrical system better.


2022 ◽  
Vol 904 ◽  
pp. 35-41
Author(s):  
Hua Zhou ◽  
Jian Xin Ding ◽  
Zhi Cheng Zhang ◽  
Zhan Jun Wang

The water temperature distribution and spatio-temporal variation law of the reservoir have a great influence on the water quality and ecological environment of the reservoir, and it is also an important temperature boundary condition for the design of concrete dam of hydropower station project, which is of great significance for the optimal design and operation of the reservoir. There are many factors affecting the water temperature of the reservoir, and it is difficult to predict the water temperature distribution accurately because of the lack of data and experience. In this paper, a numerical analysis model is established for the reservoir of a hydropower station on the Nam Ngum in Laos, and the water temperature of the reservoir is calculated and predicted, and the water temperature distribution in the reservoir and the water temperature distribution in front of the dam are analyzed and discussed. The results show that the solar shortwave radiation is the main factor affecting the temperature stratification of the reservoir. The stable low temperature layer of the reservoir is not obvious, but there is a tendency to form stratification. The research results can provide water temperature value for the design of concrete dam of the hydropower station and provide reference for the prediction of the water temperature of other similar reservoirs.


2022 ◽  
Vol 904 ◽  
pp. 43-49
Author(s):  
Bai Xue Fu ◽  
Wei Wang ◽  
Zi Yuan Cheng ◽  
Yu Bao

Using ultrasonic time difference method to test automobile fuel consumption, the test accuracy mainly depends on the testing system timing accuracy and ultrasonic flow sensor output signal-to-noise ratio. At present, the timing accuracy of the single-chip can reach the level of picosecond, and the noise mixed in the output signal of the ultrasonic converter is the main factor affecting the accuracy of fuel consumption testing. When the receiving signal contains noise, it will cause the signal amplitude to fluctuate, making the measurement time error. The analysis of same-frequency noise, circuit noise and colored noise is carried out, and the feasible measures to eliminate noise are put forward to provide reference for accurate calculation of sound and development of high-precision automobile fuel consumption test instruments.


2021 ◽  
Vol 903 ◽  
pp. 11-16
Author(s):  
M.A. Manjunath ◽  
K. Naveen ◽  
Prakash Vinod ◽  
N. Balashanmugam ◽  
M.R. Shankar

Polymethyl methacrylate (PMMA) is one among few known photo-polymeric resin useful in lithography for fabricating structures having better mechanical properties to meet the requirement in electronics and biomedical applications. This study explores the effect of Photo Initiator (PI) concentration and also curing time on strength and hardness of Polymethyl methacrylate (PMMA) obtained by UV photopolymerization of Methyl methacrylate (MMA) monomer. The UV LED light source operating at the wavelength of 364 nm is used with Benzoin Ethyl Ether (BEE) as photo initiator. The curing of PMMA resin is supported with peltier cooling device placed at the bottom of the UV light source. The characterisation study of UV photo cured PMMA is analysed through nano indenter (Agilent Technologies-G200). The current work investigates the influence of PI concentration and curing time in achieving maximum mechanical properties for UV photopolymerized PMMA.


2021 ◽  
Vol 903 ◽  
pp. 79-89
Author(s):  
R. Sundara Rao ◽  
K. Hemachandra Reddy ◽  
Ch.R. Vikram Kumar

In an internal combustion engine poppet valve is the crucial component which often opens and closes, thereby regulating gas flow in an engine cylinder. During engine operation, the valve is exposed to high temperature gases (thermal load) along with spring and cam loads (mechanical load). Due to high temperatures and fatigue loads, the valves are subjected to metallurgical changes and leads to failure. In order to resist these extreme conditions of high temperature and mechanical loads, the engine valve should possess special properties such as high surface hardness, a good amount of thermal conductivity, and fatigue strength. In this work, the reasons for the failure of two wheeler engine valve were evaluated and found that failure takes place due to change in the chemical composition mainly due to thermal diffusion at the interfaces. Thermal barrier coatings on the valve surface arrest the temperature load and increase its life. In this work, the performance of various titanium based composite coatings, i.e., TiN, TiC, TiC-Al2O3, TiCN, TiAlN, TiN- Al2O3, DLC, and uncoated valves of two wheeler engine was simulated using Finite Element Analysis. The simulation results indicated that coated valves have less thermal and fatigue loading and have more life than the uncoated valve. The Finite element simulation results of both coated and uncoated valves are presented and analyzed in this paper.


2021 ◽  
Vol 903 ◽  
pp. 125-132
Author(s):  
T.R. Mohan Kumar ◽  
P.V. Srihari ◽  
Sahas ◽  
M.S. Krupashankara

Higher solar absorptance and lower thermal emittance are the key factors for solar collectors. The use of thin films that are having mechanically resistant coatings are common practice in industries. The primary motivation of carrying this research work is to lower thermal emittance and maximize solar absorptance on SS304 substrate material. W-Al2O3 composite coatings are developed using magnetron sputtering process by considering the process parameters. The experimental plan is achieved based on Taguchi L9 orthogonal under various levels for deposition parameters. The tungsten and alumina thin films deposited using a co-sputtering were characterized using 410 - solar instrument for measuring solar absorptance and ET 100 Emissometer for measuring thermal emittance. The optimization for process parameters on thermal emittance and absorptance were carried out. It was found that for deposition parameters of DC power 750W, RF power 1050W and Argon gas flow rate of 250 sccm, absorptance of 0.758 with thermal emittance of 0.061 is observed with deposition was carried out on SS304 substrates.


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