Advanced Materials Research Vols. 779-780

Abstract: Surface tension of ferrofluid, an important parameter enclosing the boundary condition of ferro-hydrodynamic ( FHD ) problem, is investigated in this study. Referred to modified Langevin function and apparent weight loss theory, an auxiliary experimental mechanism of ring-pull method is then designed and set up, which will be used to determine the surface tension of testing sample through various magnetization degree induced by field intensity. While compared with the results predicted from Rayleigh theory using commercial product of Matsumoto Co., an excellent agreement is delivered within the working magnetic intensity 0~40 mT. Here dimensionless parameter α is found to dorminate the prompt increase of surface tension coefficient as the ferro-magnetization ratio reaches at 70 % saturation magnetization. .

Abstract: The hot compression deformation behavior of Mg-4Al-1Zn-0.5Mn-0.5Ca (AZ41M) alloys during twin roll casting and hot compression (350-400 oC/0.1-1s^-1) has been studied. Owing to adding Mn and Ca in AZ41 alloy, the deformation behavior and microstructure exhibit largely changes under different conditions. A bimodal structure consisting of a large fraction of deformed grains and a small fraction of newly formed grains are found in as-deformed alloys. Equiaxed and fine-grained microstructures occur in as-annealed samples. Al-Mn and Al-Ca compounds result in grain and Al-Mg intermetallic refinement.

Abstract: This paper deals with heat transmission through porous material subjecting to high levels of radiation. In depth absorption of radiant energy would lead to increased in-depth temperature which would cause a thicker pyrolysis zone, that lead to uncontrolled material spallation and failure. Analytical treatments of such problems had been attempted by many researchers [, approaches vary from theoretical principles to engineering correlations, but unfortunately no appropriate temperature and pressure-dependent material properties are available which are needed for their estimations, and extensive experimental measurements would still be required for their evaluations. This paper describes an experimental system developed for direct measurement of radiation transport parameters which is developed with reference to the experimental setups of previous investigators.

Abstract: The high-density ammonium polyvanadate was prepared by means of fine-grained ammonium polyvanadate (APV) produced in vanadium plant. The effects of amount of fine particles, temperature and pH of vanadium solution on preparation of high-density ammonium polyvanadate were investigated. The research results showed that the density of APV could be achieved 0.88g/cm³ under the conditions of addition of 13-31% fine particles, temperature range from 70°C to 100°C and the pH of vanadium solution range from 2.5 to 4, but loss rate of vanadium was the lowest. Moreover, the particle size of high-density ammonium polyvanadate mainly distributes in range of 10 ~ 90μm and is significantly larger than that of the fine APV particles, on the basis of results of the laser particle size analyzer.

Abstract: In order to study the effect of several factors on the shrinkage performance of lime-fly ash stabilized crushed stone, temperature shrinkage coefficients and dry shrinkage coefficients of mixtures with different gradations, lime and fly content and age were measured. Results indicate that mixture with a stone-on-stone contact has better shrinkage-resistance performance; For the same gradation, both dry shrinkage coefficient and temperature coefficient become improved with lime-fly content increasing; when the lime-fly content is the same, temperature shrinkage coefficient increases with longer age; Results of analysis of variance show that to the temperature shrinkage coefficient, the effect of age and lime and fly content are important, and the latter is greater. To the dry shrinkage coefficient, gradation and lime and fly content are important factors, and the former is greater.

Abstract: The axial compressive stress-strain relationship of concrete reflects its basic mechanical performance, which is important in analyzing the performance of materials, especially in the analyzing of the elastic modulus, ductility and carrying capacity. In order to study the mechanical properties of polymer-modified concrete and steel fiber reinforced polymer concrete, a comparative study of the compressive stress-strain relationship of polymer-modified concrete and steel fiber reinforced polymer concrete was carried out, the complete compressive stress-strain curves were obtained, and the influence of polymer and steel fiber on concrete elastic modulus and compressive ductility was also studied. It is demonstrated that the compressive ductility index of steel fiber reinforced polymer concrete can reach 7.39 which is greater than that of polymer-modified concrete with the same ingredients. The results also show that steel fiber reinforced polymer concrete is better than both polymer-modified concrete and steel fiber reinforced concrete.

Abstract: In this paper the behavior of crack propagation of the strip steel is investigated by using the Gurson-Tvergaard-Needleman (GTN) damage model. The damage parameters used in the damage model are determined by tension experiments and SEM observation. With the aid of finite element method the influences of rolling ruduction and tension on crack propagation are systematically analyzed. The numerical results show that the GTN damage model is available to prediction the initiation and propagation of edge cracks during rolling forming process and the simulation results agrees well with the experimental results.

Abstract: Aiming at the center shaft bracket sheet extension parts, its stamping calculation is simulated based on the sheet metal forming with nonlinear finite element software Dynaform. The contours varying with blank holder forces, friction coefficients and material performance parameters (sheet hardening exponent n and thick anisotropic coefficient r) are obtained by using the simulation software. The impact of the factors on the central shaft bracket parts stamping is analysised by using the contours, provide the theory to eliminate the fold and fracture in the stamping process.

Abstract: The effects of pullulan and glycerol on the tensile properties and optical properties of gelatin-based edible film were studied. It showed that the adding of pullulan dramatically improved the elongation at break of edible film, when the amount was 50%(percentage by weight, same followingly), the tensile strength and the luminousness reached the best. The adding of glycerol could both increase the elongation at break and optical properties of edible film, when the amount was 20%, the tensile strength reached the best.

Abstract: Based on the data got from actual measurement of mineral filler and aggregate surface area, this paper is going to present a new method, which is different from conventional approaches, to help to determine aggregate surface area. A formula that can be used to calculate aggregate surface area will be obtained. Currently, many methods are available to calculate asphalt film thickness. These methods are not perfect and deserve a new survey. Therefore, by referring to and analyzing those existing methods, this paper will put forward a revised, updated and instructive calculating formula to guarantee the accuracy of calculation.