Papers by Keyword: Temperature Effect

Abstract: The aim of this study is to evaluate the effect of temperature during the synthesis of alumina by combustion in a muffle furnace. The alumina was characterized by X-ray diffraction, particles size distribution and scanning electron microscopy. The results showed that the synthesis temperature of the alumina can affect the structure of the produced samples. The size distribution of the median particle diameter reached higher value for the alumina synthesized at 500°C with 16.07 μm, the range of the total distribution of particles is introduced to the large alumina synthesized 500 and 600°C and close synthesized when 700 and 800°C. The phase of the alumina was identified only after the synthesized sample at 800°C with crystallite size of 22.16 and 6.75 μm synthesized samples 800 and 900°C, respectively. With respect to morphology, increased synthesis temperature was not enough to significantly change.

Abstract: The temperature history of HPC remarkably affects their volume stability and mechanical properties, but no enough attention is pay to it in the literature. In this paper, for the purpose of clarifying the temperature effect of above-mentioned behaviors, a series of tests on autogenous deformation, compressive strength and elastic modulus of HPC are carried out. The outcome of research as follows: surrounding temperature intensely influences autogenous strain and mechanical indices; elevated temperature not only results in increased shrinkage strain, compressive strength and elastic modulus, but also accelerates their rates of development.

Abstract: In this paper, FBG temperature sensor and strain sensor have been used to monitor shrinkage and temperature of concrete retaining wall in construction site within its casting early age. As FBG senses both strain and temperature simultaneously, thermal shift of FBG strain senor is compensated by FBG temperature sensor. The test results indicate that this FBG monitoring system is feasible for monitoring concrete properties at its early age. The dual FBG monitoring technique applied in this research could be extended to monitor shrinkage and temperature for other concrete structures.

Abstract: The mechanical properties of granite experiencing high temperatures under uniaxial compression condition were simulated in this paper. Numerically simulated stress-strain curve, peak stress, peak strain and the tangent elastic modulus were compared with the corresponding physical tests. Simulated results agree well with physical tests results, it is shown that Abaqus is suitable for the analysis of the temperature effect on rock fracture.

Abstract: The potential impact of high permittivity gate dielectrics on the performance of a ballistic nanoscale CNTFET is studied over a wide range of dielectric permittivities with low temperatures ranging from room temperature down to 100 K. Using the non-equilibrium Greens function (NEGF) formalism. Device characteristics such as I_ON/I_OFF current ratio, threshold voltage, the drain induced barrier lowering (DIBL). The effects of temperature varying are also examined.

Abstract: Forests cover 30% of global land area and maintain 73% of global soil carbon which is important to the global carbon cycle. In forest ecosystem, climate was expected to affect the quality and quantity of environmental materials (detritus) inputs to soil and soil chemical and physical processes which then affected carbon storage technically. Thus, altitude provided a wonderful site for this environmental research. We collected five soils along the altitudinal gradient on the Changbai Mountain in the North Temperate Zone to analyze the soil properties and carbon content. The results showed the highest SOC content was observed at lowest altitude for the larger plants residues (environmental materials). Except the lowest altitude, the amount of SOC increased with altitude for the low decomposition under the cold temperature. Multiple environmental factors (such as soil type, topography and vegetation) were thought to regulate SOC technically.

Abstract: It exists a great influence on deformation and internal force of large span bridge when temperature changes, the influence of the temperature must be considered and try to avoid in the process of construction control. Under monitoring to the construction process of Tieluoping super-large bridge on the scene, the influence law on internal force of Tieluoping Bridge is analyzed considering temperature effect, and the influence considering the sunshine temperature difference on cable tower deviation and stress is obtained, and the size of influence of main girder elevation, cable force and strain because of temperature field and distribution rule internal temperature field are clear. It provides powerful help for the smooth construction.

Abstract: The effect of titanium and aluminum contents, strain, strain rate and tested temperatures on the mechanical properties and microstructural properties will be investigated in this study. These cobalt base super alloys are to be tested using material testing system (MTS) at strain rates of 10-3, 10-2 and 10-1s-1 and at temperatures of 700°C, 500°C and 25°C respectively. It is found that the flow stress increases with increasing strain rate and Ti and Al contents, but decreases with increasing temperature. Furthermore, the strain rate sensitivity increases with increasing strain rate, but decreases with increasing temperature. The microstructural observations confirm that the mechanical response of the cobalt superalloy specimens is directly related to the effects of the titanium and aluminum contents, strain rate and temperature on the evolution of the microstructure. It can be observed that the strengthening effect in cobalt suprealloy is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature.

Abstract: Recovery of iron from the waste slag is of great interest for maximum use of mineral resource, reduction of environment impact and improvement of economical benefits to the related companies. This paper is mainly focused on the effect of the temperature on recovery of iron from waste slag of pyrite processing using reduction-roasting magnetic separation method. The experimental results show that under the treatment condition in this work about 70% of the iron was recovered from the waste slag, where the iron content in the concentrate is 57%. After the further treatment with chlorinated segregation-magnetic separation, the iron content in the recovered slag can reach 83%

Abstract: The temperature stress calculation of multi-storey structure is very complicated. Many researches have been taken for the frame structures with rectangular plane, but very few references about annular plane. Based on the ANSYS program, the structure temperature effect of a multi-storey reinforced concrete frame which plane shaped like the elliptic is analyzed in this paper. The overall temperature load and concrete shrinkage equivalent temperature are considered in the analysis. The results reflect that curvature has an apparent influence on the temperature stress of annular super-long structure. Besides, the structure temperature effects are studied on both cases of the structure with expansion joint and without it, which shows that reasonable installation of expansion joint can decrease the temperature stress of annular structure. The influence of structure member rigidity on temperature effect is also discussed by changing the size of the section; all of these could offer reference for engineering design.