Abstract: In order to study the residual stress of the auto-frettagea super high pressure vessel effectively, a new stress and strain analytical formula is brought forward. It indicates that this analytical formula is more accurate under actual conditions for the steel applied in auto-frettagea super high pressure vessel through strict mathematical testimony. Subsequently, it describes how to establish this analytical formula and analyzes the analytical formula’s error through taking some material as an example. It illustrates that it is feasible and reliable to solve this new analytical formula basing on general tensile curves through this instance. The analytical formula is also of theoretical signification and engineering practical value in application.
Abstract: TiO2 ceramics doped with 0.1 mol% Ta2O5 and different concentrations of rare earth oxide Sm2O3 were obtained by sintering at 1450 °C. As a varisor material, the microstructure, the nonlinear electrical behavior and dielectric properties of these ceramics were investigated. SEM and XRD were carried out to study the change of microstructure. The results show that there exist second phase (Sm2Ti2O3) on the surface on the surface of TiO2 grains. The ceramics have nonlinear coefficients of α = 2.0-4.0 and ultrahigh relative dielectric constants which is up to 104. The sample doped with 0.5 mol% Sm2O3 exhibits high nonlinear constant of 3.7, low breakdown voltage of 21.5 v/mm, ultrahigh electrical permittivity of 4.25× 104 and low tanδ of 0.37. It is suggested that the sample doped with 0.5 mol% Sm2O3 forms the most effective boundary barrier layer. The defects theory was introduced to illustrate the nonlinear electrical behavior of TiO2-Ta2O5-Sm2O3 varistor ceramics.
Abstract: The tribological behavior of continuous frame ceramic reinforced Al-based alloy against Cr12 steel has been studied with oscillating dry friction and wear tester under the testing conditions of 70°C, 270°C, and 30min, and the load range is from 40N to 100N. The analysis of experimental results show that it is characteristic of abrasive wear and oxidation wear mechanisms for continuous ceramic/Al-7075 composites. The friction resistance of comb ceramic reinforced composite is better than foam ceramic reinforced composite, since the former is with continuous ceramic frame on the worn surface while the latest is with discontinuous hard convex on the plane; and the metal matrix filling in comb ceramic is not continuous in 3-D space, which leads to the deterioration of thermal metal softening at high temperature. Therefore, the composite reinforced by 2-D comb ceramic exhibits better high-temperature friction resistance than the one reinforced by 3-D foam ceramic.
Abstract: The estimation of the epipolar geometry is of great interest for a number of computer vision and robotics tasks, and which is especially difficult when the putative correspondences include a low percentage of inliers correspondences or a large subset of the inliers is consistent with a degenerate configuration of the epipolar geometry that is totally incorrect. The Random Sample Consensus (RANSAC) algorithm is a popular tool for robust estimation, primarily due to its ability to tolerate a tremendous fraction of outliers. In this paper, we propose an approach for improve of locally optimized RANSAC (LO-RANSAC) that has the benefit of offering fast and accurate RANSAC. The resulting algorithm when tested on real images with or without degenerate configurations gives quality estimations and achieves significant speedups compared to the LO-RANSAC algorithms.
Abstract: Simulation with CFD and local test are two main methods in study on air flow in large space building. This paper tests and simulates thermal comfort and air distribution of existing air- conditioning mode of some exhibition center. Through comparison and analysis on existing and simulated air-conditioning pattern, draw a conclusion that it’s feasible to simulate thermal comfort and air distribution of air-conditioning. And the research is important to guide energy efficiency and design optimization of air-conditioning system in large space building.
Abstract: The sintering and dissolution process (SDP), in which NaCl is used as space holder, was used to produce open-cell Ag foams with various pore sizes. The content, size and shape of NaCl particles dictate the pore architecture of the foams. The yield strength of Ag foams decreases with increasing porosity. Of equivalent porosity, the yield strength of the foams with larger pore size is also higher than the foams with smaller pore size.
Abstract: SiC filament was prepared by Chemical Vapour Deposition method using W wire as the substance material. The combination between W wire and SiC became a key element influencing tensile strength of SiC. In this paper, tensile fracture morphology of SiC filament was analyzed, from which interface combination between SiC and W wire was discussed under different deposition temperature and the influence of interface layer’s thickness on final tensile of SiC filament was given. How to control the thickness of interface layer is a key factor for improving performance of SiC filament.
Abstract: Cheng’s refined theory is extended to investigate torsional circular shaft of two-dimensional dodecagonal quasicrystal (2D dodecagonal QCs), and Lur’e method about harmonic function is extended to harmonic function in the respective cylindrical coordinate. The exact deformation of torsional circular shaft of 2D dodecagonal QCs under reverse direction surface loading is proposed on the basis of the classical elasticity theory and stress-displacement relations of 2D dodecagonal QCs, and the exact deformation theory provides the solutions about torsional deformation of a circular shaft without ad hoc assumptions. Exact solutions are obtained for circular shaft from boundary conditions. Using Taylor series of the Bessel functions and then dropping all the terms associated with the higher-order terms, we obtain the approximate expressions for circular shaft of 2D dodecagonal QCs under reverse direction surface. To illustrate the application of the theory developed, one example is examined.
Abstract: Functionally Graded Material (FGM) is a class of material wherein the properties and structure are varied intentionally from one side to the other side of the specimen. This paper describes the effect of L/D (Length to Diameter) ratio of the cast on cast Al-Si FGM. The present study uses Al-17%wt Si to cast FGM's. The cast is evaluated for Microstructure and Hardness all along the length of the specimen. Three L/D ratios: 0.5, 1.0, 1.5 were cast using the Centrifuge Technique. The microstructures showed that enrichment of primary Si was largest in 1.5 ratio compared to other two. Hardness value of the cast at the upper and lower region were examined and found that gradient of hardness was more in 1.5 case. High volume percentage of primary Si was nearly 26% in the upper region and a hypoeutectic structure in the lower region.
Abstract: In recent years, along with realize to the environmental protection of strengthen increasingly, make use of various industry to discard the conduct and actions of builds road the material already widespread be subjected to the people of value. Make the grass-roots material to construct with the coal stone the road contain many advantages, not only can economize the resources of the land, but also found out a fit path for the processing of this kind of industry wastes. This text combines the construction of the express line of a mountain City to be the advantage that the road faces the grass-roots material and applied the scope, economic performance...etc. to make some studies for the coal stone.