Deployment Analysis of Deployable Structures Based on Linkages Considering Thermal Effect

Author(s):  
Jian-guo Cai ◽  
Jian Feng ◽  
Yao-zong Zhao

The thermal stress due to temperature rise may increase the element strain and internal forces, which may lead to the failure of the deployment of deployable structure. However, few works are carried out to study the dynamic performance of the flexible multibody under different temperatures, especially for deployable structures that work in space environments. Based on this idea and formulation of finite element methods, the dynamic equations of the system considering the temperature effect are derived. Then two examples, a parallel four-bar linkage and a non-parallel four-bar linkage, are presented in this paper to study the influence of thermal loading on the structural behavior during the motion. The results show that the effect of temperature changes is slight for the parallel four-bar linkage, but the influence is significant for the non parallel four-bar linkage. It can be concluded that the former case may be more suitable for the deployable structures in space environment.

Author(s):  
Rasim Alper Oral ◽  
Mahmut Dogan ◽  
Kemal Sarioglu ◽  
Ömer Said Toker

Abstract Pekmez (molasses) is a traditional food commonly produced from grape and other kind of fruit juices by evaporation processes. In this study, 5-Hydroxymethylfurfural (HMF) level of various pekmez samples was investigated during storage at different temperatures. HMF content of apricot, mulberry, carob, grape, Juniperus communis pekmez changed from 133.0 ppm to 1060.5 ppm, from 88.2 to 1921.5 ppm, from 11.1 to 1153.6 ppm, from 75.5 to 2077.0 ppm, from 19.9 to 280.1 ppm throughout eight months storage period, respectively. Samples of pekmez from the Juniperus communis had the minimum k values for each temperature that means HMF formation in these samples were slower than other pekmez types. The kinetic data analysis for HMF formation during storage was performed and an Arrhenius equation was used to determine the effect of temperature on reaction kinetics of 5-HMF formation in pekmez samples. Ea values were found between 10.58–37.73 (kcal/mol). Apricot pekmez was found as the least sensitive sample to HMF formation resulted from temperature changes.


2022 ◽  
Vol 906 ◽  
pp. 69-76
Author(s):  
Tigran Petrosyan

In order to study the effect of temperature changes on the dissipative properties of materials, two approaches are used. The first approach implies introducing some temperature function under the sign of the integral in the heredity theory equation and simultaneously taking into account the dependence of the elastic modulus on temperature. As a result, based on experimental data on the thermal creep of soils, the expression for determining the hysteresis energy losses under the periodic voltage changes was obtained depending on temperature changes.According to the second approach, the expression for determining the hysteresis energy losses under isothermal conditions at different temperatures was obtained by introducing into the heredity theory equation an approximation of the experimental dependences of instantaneous deformation and temperature creep parameters for steel Kh18 N10T.


2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.


2018 ◽  
Vol 77 (6) ◽  
pp. 375-381
Author(s):  
K. M. Popov

Abstract. Influence of air temperature on the consumption of fuel and energy resources (FER) on train traction is due to a number of physical laws. The extent of this effect is specified in the Rules for Traction Settlement (RTS). At the same time, when rationing FER consumption for train traction, a specialized methodical base is used, which involves a different approach to accounting for the effect of temperature on FER consumption for train traction. At the same time in different documents of this base, the effects of low temperature on the absolute and specific consumption of fuel and energy resources on train traction are taken into account in a different way, which is due to the lack of consensus among specialists on the way this factor is taken into account. Specialists of JSC “VNIIZhT” carried out an analysis of a significant amount of driver’s routes data, results of which showed that the dependence of the specific flow rate on temperature, on the basis of which the corresponding influence coefficient is determined, needs to be periodically updated. In addition, when technically standardizing the consumption of fuel and energy resources (for the locomotive crew work site), the temperature effect coefficients need to be calculated for a specific work area and direction of motion on it, while using the average network coefficient values will lead to errors. When calculating additional flow of fuel and energy from the effect of temperature for electric multiple units (EMU), the equations of regression dependencies should be used, obtained by statistical processing of data on temperature changes and specific consumption of fuel and energy resources for EMU and determined for each series of EMU when working on a particular suburban area.


Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.


Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 134
Author(s):  
Ana Isabel Galván ◽  
Alicia Rodríguez ◽  
Alberto Martín ◽  
Manuel Joaquín Serradilla ◽  
Ana Martínez-Dorado ◽  
...  

Dried fig is susceptible to infection by Aspergillus flavus, the major producer of the carcinogenic mycotoxins. This fruit may be contaminated by the fungus throughout the entire chain production, especially during natural sun-drying, post-harvest, industrial processing, storage, and fruit retailing. Correct management of such critical stages is necessary to prevent mould growth and mycotoxin accumulation, with temperature being one of the main factors associated with these problems. The effect of different temperatures (5, 16, 25, 30, and 37 °C) related to dried-fig processing on growth, one of the regulatory genes of aflatoxin pathway (aflR) and mycotoxin production by A. flavus, was assessed. Firstly, growth and aflatoxin production of 11 A. flavus strains were checked before selecting two strains (M30 and M144) for in-depth studies. Findings showed that there were enormous differences in aflatoxin amounts and related-gene expression between the two selected strains. Based on the results, mild temperatures, and changes in temperature during drying and storage of dried figs should be avoided. Drying should be conducted at temperatures >30 °C and close to 37 °C, while industry processing, storage, and retailing of dried figs are advisable to perform at refrigeration temperatures (<10 °C) to avoid mycotoxin production.


Author(s):  
Yiqun Huang ◽  
Pawan Singh Takhar ◽  
Juming Tang ◽  
Barry G Swanson

Rheological behaviors of high acyl (HA) gellan are not well understood partially because of its relatively late commercialization compared to low acyl gellan. The objective of this study was to investigate the effect of temperature (5-30 °C), calcium (0, 1 and 10 mM) and gellan concentrations (0.0044-0.1000% w/v) on the flow behaviors of high acyl gellan aqueous solutions using rheological tests. Gellan solutions with 0 or 1 mM added Ca++ exhibited shear thinning behavior at gellan concentrations above 0.0125%. The influence of temperature on apparent viscosity (shear rate, 100 s-1) of gellan solutions can be described with an Arrhenius relationship. The apparent viscosity of gellan solution at low concentrations was more sensitive to temperature changes. The addition of Ca++ led to a decrease in flow resistance for a dilute gellan solution (<0.0125%), but an increased resistance for a relatively concentrated gellan solution (>0.0125%).


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 119
Author(s):  
Dana H. Abdeen ◽  
Muataz A. Atieh ◽  
Belabbes Merzougui

The inhibition behavior of carbon nanotubes (CNTs) and Gum Arabic (GA) on the corrosion of 316L stainless steel in CNTs–water nanofluid under the effect of different temperatures was investigated by electrochemical methods and surface analysis techniques. Thereby, 316L stainless steel samples were exposed to CNTs–water nanofluid under temperatures of 22, 40, 60 and 80 °C. Two concentrations of the CNTs (0.1 and 1.0 wt.% CNTs) were homogenously dispersed in deionized water using the surfactant GA and tested using three corrosion tests conducted in series: open circuit test, polarization resistance test, and potentiodynamic scans. These tests were also conducted on the same steel but in solutions of GA-deionized water only. Tests revealed that corrosion increases with temperature and concentration of the CNTs–water nanofluids, having the highest corrosion rate of 32.66 milli-mpy (milli-mil per year) for the 1.0 wt.% CNT nanofluid at 80 °C. In addition, SEM observations showed pits formation around areas of accumulated CNTs that added extra roughness to the steel sample. The activation energy analysis and optical surface observations have revealed that CNTs can desorb at higher temperatures, which makes the surface more vulnerable to corrosion attack.


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