Advanced Materials Research Vol. 700

Abstract: The designing level of material selection and sizes optimization of casing material for heavy oil thermal recovery wells play a key role in the expected production target to heavy oil thermal recovery wells. This paper introduces the material selection of tubing and casing for heavy oil thermal recovery wells and proposes the optimization idea and technique of tubing material selection. By application, the study above has a good practicality.

Abstract: Study of bonded post-tensioned prestressed concrete construction technology, from materials, equipment, channel reservation, prestressed reinforcement material installation, concrete pouring, the prestressed tendons tension and grouting of anchor seal is described from the aspects of the construction of the link, the specific operation steps, summarizes the method of construction, improve the following prestressed concrete construction understanding.

Abstract: Finite element method is employed to analyse tensile stress at the bottom of asphalt concrete layer and semi-rigid base, tension strain, road surface deflection and shear stress in asphalt concrete layer. The influence of graded macadam bases modulus on mechanical properties is studied. Meanwhile considering field modulus test values, reasonable value of graded macadam bases modulus, which is suitable for each road grade and each layer position, is proposed.

Abstract: There are many ground source heat pumps in engineering construction application. However, Research on heat exchanger models of single-hole buried vertical ground source heat pump mostly focuses on single U-tube ground heat exchangers other than double U-tube ones in China currently. Compared with single U-tubes, double U-tubes have the heat transfer particularity of asymmetry. Therefore, the use of the traditional single tube models would have large error in the simulation of the actual double U-tube heat exchangers. This paper frames a three-dimensional heat transfer model for the vertical single-hole buried double u-tube heat exchanger in a ground source heat pump system. The model considers the performance of U-bube material and uses a dual coordinate system and makes the control elemental volumes superimposed.

Abstract: Thermal environmental problems in urban high-rise buildings are prevalent. To analyze the phenomenon, the thermal environment of a typical urban residential subdistrict is simulated by using CFD techniques considering the affects of different type of wall material. The simulation data are carefully analyzed. Some useful results are thus obtained. The direction of the buildings affects air circulation greatly with the north-south orientation having the best effects. Temperature in the subdistrict is about 3~5°C higher than its surroundings because of heat island effects which could be weakened if greening rate of the sbudistrict is increased. Finally, simulation results show that wall materials affect the environment considerably.

Abstract: This paper taking Jinjie Mine in northwest China as an example, on the basis of the hydrogeological analysis of the mineral deposit, explores the structure and influence factors of mine water inflow. The result shows that Jinjie Mine coal mining has destroyed the water-resisting roof layer, and then conducted the water channels. As a result, the original mode of hydrological cycle is changed, resulting in pore water, fissure water and surface water flow into the goaf through the water channel, and this help the water inflow be quite large (even reach 5380 m³/h). In order to coal mine safety production and protection of the areas fragile water environment, the curtain grouting technique using fly ash cement materials mainly is taken for preventing water.

Abstract: When energy loss appears around cores and copper windings, cooling down the temperature timely has immense influence on transformer life and safe operation. In this paper, a serious of methods are proposed, which enhancing heat transfer of panel type radiators placed on the surface of the oil-immersed power transformers. When adding some turbulators on the panel type radiators and choosing the location of them appropriately, heat transfer effection can get a certain degree of improvement. Heat pipe is currently accepted efficient heat transfer element. Using the perfect heat transfer effect of heat pipe, with some necessary structural transformation, capacity of panel type radiator can be improved. New types of panel shape increase the effective heat transfer area, meanwhile damage the surface bounding layers. Therefore, optimization design with theory and simulation is a significant research field, by changing many kinds of structure parameters, for instance, the panel oil passage number and non uniform size distribution, inclination angle of up oil pipe and so on. Considering from actual condition, production process is simple, by using stainless steel, and owns a high level of automation, receiving lower energy consumption.

Abstract: The muscle tendon is connective tissue, the fracture can occur when its stress is not reasonable. With the establishment of tendon external and endogenous coalescence theory, the suppression of external coalescence and promotion of endogenous coalescence became the crucial problem of resolve adhesion of tendon. The application of adhesion prevention materials in the part of tendon surrounding was the hotspot of recent research. At present, the research about adhesion prevention materials has made remarkable achievements. However, the materials studied in exercise-induced tendon rupture were cut both ways, therefore, as a material for adhesion prevention and functional reconstruction to treatment of tendon rupture. There are still many unsolved problems in the application of adhesion prevention materials.

Abstract: In the present study, the experiments were investigated with the effect of enzyme concentration, pH, time and temperature on the enzyme activity of the immobilized β-galactosidase on Chitosan beads with material properties. The enzyme activity will be measured after completing immobilized and expressed as the absorbency at the wavelength of 420 nm. In the process, there were major differences between the different conditions during immobilization. As the result,the optimal conditions were that adding chitosan beads into 8 mg/ml β-galactosidase solution (pH6.5) and adsorbed 6 h at 25°C.

Abstract: effect of five materials including sucrose, lactose, skim milk, yeast, vitamin B₂ on survival rate of Lactobacillus bulgaricus during freeze-drying was studied by measured survival and the number of viable cells. Designed different concentrations of these different protective agents, respectively, freeze-drying perfectly and then counted the survival ratio of Lactobacillus bulgaricus and the number of viable cells. Results were as follows: addition of skim milk and yeast had significant effects while addition of vitamin B₂ had minimal impact on survival rate of Lactobacillus bulgaricus. The optimum concentration of single protective agent of Lactobacillus bulgaricus during freeze-drying was that 25% (W/V) sucrose, 20% (W/V) lactose, 25% (W/V) skim milk, 20% (W/V) yeast and 25% (W/V) vitamin B₂, respectively, and survival rate was 24.5%, 35.6%, 64.4%, 62.2%, and 16.3%.