Heat Flux Characteristics of Asymmetrically Heated and Cooled Thermal Stimuli

Author(s):  
Mehdi Hojatmadani ◽  
Matthew Hardy ◽  
Ahmad Manasrah ◽  
Rasim Guldiken ◽  
Kyle Reed

The human thermal response system can be manipulated by the proper combination of applied hot and cold stimuli. Previous research has shown that a sensation of constant cooling can be perceived through the application of certain patterns on the skin. Here we focus on (1) exploring the heat flux characteristics of the thermal display through computer simulations, (2) testing a hypothesis about the relationship between thermal sensation and heat flux, and (3) examining modifications of the thermal display patterns to intensify thermal sensations. To characterize the heat flux patterns of the thermal display, finite element simulations were performed using ANSYS. Simulations were done in two parts: the first examined a small subregion between heating and cooling stimuli, and the second was a larger scale examination of the heat flux profile of the thermal display. It was observed that the heat flux profiles for all thermal patterns were approximately identical. A linear relationship is derived between simulation and experimental results. This relationship was then used to determine the theoretical thermal sensations to determine which are best suited for future physical experimentation on humans.

Author(s):  
Lin Hao ◽  
Jinhao Qiu ◽  
Hongli Ji ◽  
Rui Nie

Phenomenological model on thermo-mechanical response of shape memory alloy (SMA) strip is presented in this paper. Thermal response and transformation accompanied deformation are described by the proposed model. Newly transformation expansion tensor is defined to describe the relationship between the transformation-induced deformation of the strip and the temperature. The model is then implemented into ABAQUS by using the user-defined subroutine. Finally, the proposed model is verified by the comparison between the finite element simulation and experiment.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 1337-1345
Author(s):  
Chuan Zhao ◽  
Feng Sun ◽  
Junjie Jin ◽  
Mingwei Bo ◽  
Fangchao Xu ◽  
...  

This paper proposes a computation method using the equivalent magnetic circuit to analyze the driving force for the non-contact permanent magnet linear drive system. In this device, the magnetic driving force is related to the rotation angle of driving wheels. The relationship is verified by finite element analysis and measuring experiments. The result of finite element simulation is in good agreement with the model established by the equivalent magnetic circuit. Then experiments of displacement control are carried out to test the dynamic characteristic of this system. The controller of the system adopts the combination control of displacement and angle. The results indicate that the system has good performance in steady-state error and response speed, while the maximum overshoot needs to be reduced.


Author(s):  
Youngsup Song ◽  
Yangying Zhu ◽  
Daniel J. Preston ◽  
H. Jeremy Cho ◽  
Zhengmao Lu ◽  
...  

2019 ◽  
Author(s):  
Chem Int

Mathematical model was developed and evaluated to monitor and predict the groundwater characteristics of Trans-amadi region in Port Harcourt City. In this research three major components were considered such as chloride, total iron and nitrate concentration as well as the polynomial expression on the behavious on the concentration of each component was determined in terms of the equation of the best fit as well as the square root of the curve. The relationship between nitrate and distance traveled by Nitrate concentration by the model is given as Pc = 0.003x2 - 0.451x + 14.91with coefficient of determination, R² = 0.947, Chloride given as Pc = 0.000x2 - 0.071x + 2.343, R² = 0.951while that of Total Iron is given as Pc = 2E-05x2 - 0.003x + 0.110, R² = 0.930. All these show a strong relationship as established by Polynomial Regression Model. The finite element techniques are found useful in monitoring, predicting and simulating groundwater characteristics of Trans-amadi as well as the prediction on the variation on the parameters of groundwater with variation in time.


Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 582
Author(s):  
Yoko Ono ◽  
Hidemasa Bono

Hypoxia is a condition in which cells, tissues, or organisms are deprived of sufficient oxygen supply. Aerobic organisms have a hypoxic response system, represented by hypoxia-inducible factor 1-α (HIF1A), to adapt to this condition. Due to publication bias, there has been little focus on genes other than well-known signature hypoxia-inducible genes. Therefore, in this study, we performed a meta-analysis to identify novel hypoxia-inducible genes. We searched publicly available transcriptome databases to obtain hypoxia-related experimental data, retrieved the metadata, and manually curated it. We selected the genes that are differentially expressed by hypoxic stimulation, and evaluated their relevance in hypoxia by performing enrichment analyses. Next, we performed a bibliometric analysis using gene2pubmed data to examine genes that have not been well studied in relation to hypoxia. Gene2pubmed data provides information about the relationship between genes and publications. We calculated and evaluated the number of reports and similarity coefficients of each gene to HIF1A, which is a representative gene in hypoxia studies. In this data-driven study, we report that several genes that were not known to be associated with hypoxia, including the G protein-coupled receptor 146 gene, are upregulated by hypoxic stimulation.


Author(s):  
V. Ramirez-Elias ◽  
E. Ledesma-Orozco ◽  
H. Hernandez-Moreno

This paper shows the finite element simulation of a representative specimen from the firewall section in the AEROMARMI ESTELA M1 aircraft. This specimen is manufactured in glass and carbon / epoxy laminates. The specimen is subjected to a load which direction and magnitude are determined by a previous dynamic loads study [10], taking into account the maximum load factor allowed by the FAA (Federal Aviation Administration) for utilitarian aircrafts [11]. A representative specimen is manufactured with the same features of the firewall. Meanwhile a fix is built in order to introduce the load directions on the representative specimen. The relationship between load and displacement is plotted for this representative specimen, whence the maximum displacement at the specific load is obtained, afterwards it is compared with the finite element model, which is modified in its laminate thicknesses in order to decrease the deviation error; subsequently this features could be applied to perform the whole firewall analysis in a future model [10].


Author(s):  
Guang Dai ◽  
Wei Li ◽  
Zhijun Yang ◽  
Yali Wang

According to the principle of magnetic flux leakage testing and the finite element numerical simulation, 3D finite element model (FEM) for MFL testing of tank bottom was established. Through simulative analysis, influence law between defect size and defect magnetic flux leakage field and the relationship curve of defect leakage magnetic field change with its size was obtained. The result showed that: When the length vary with sequence, the peak valley length of defects leakage magnetic signal increase with the increase of defect length, the relationship curve between each other is approximate linear; When the depth vary with sequence, the relationship between peak valley height of defects leakage magnetic signal and defect depth is also approximate linear, but this relationship was different with different length; When the width vary with sequence, on the defect symmetry plane, the peak of magnetic flux density along the width direction corresponded with the defect edge, and the length of the two peaks were equal to the width of the defect. According to simulation data and theory of regression analysis linear regression equation and relation surface between defect length depth and the characteristic quantity of its signal was established, quantitative method of defects signal was also proposed. Then experimental study was carried out in the Laboratory, the result show that the quantitative size was consistent with the actual defect size.


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