Papers by Keyword: Property Analysis

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Authors: Zhang Ming Li, Liang Liang Chen, Feng Wu, Ling Wan
Abstract: The shear strength characteristics of rock are very concerned in related underground construction. In this paper, in situ direct shear test for the weathered silty mudstone of the direct rock mass in a large section tunnel is carried out, the shear strength parameters are obtained, and some laws on the strength characteristics of this rock are got, such as that the displacement corresponds to the maximum shear stress under the given normal is decreased with increasing of normal loading number. This work provides a reference for the study of rock strength theory and its application.
Authors: Hans Eckart Exner, Günter Petzow
Abstract: Understanding porosity coarsening is essential for controlling the properties of sintered materials and for producing high density or near net shape parts. As porosity is interconnected up to relative densities in excess of 80% or even 95%, measuring, monitoring and modelling of the growth of individual pores is relevant only at very high relative densities. This paper tries to convey two essentials of porosity coarsening: (i) characterization of the geometry of the pore space in the lower range of densities is possible by using stereological parameters, and (ii) coarsening of porosity takes place during all sintering stages by various mechanisms. Porosity coarsening has been reported in metals, ceramics and glasses. Recent and classical approaches, experimental results with two dimensional model arrangements as well as computer simulations of formation and opening of particle contacts are discussed. The effect of porosity dimensions on the properties of sintered materials and measures for preventing and provoking porosity coarsening are briefly addressed.
Authors: Rômulo Crespo Tardim, Guerold Sergueevitch Bobrovinitchii, Sérgio Neves Monteiro, Ana Lúcia Diegues Skury, Marcello Filgueira
Abstract: The present work comprises a study about the possibility of obtaining polycrystalline diamond cutters through a novel method of sintering both layers at the same time. This possibility was tested through the sintering of a diamond layer over a hard metal (WC+15wt%Co) support under conditions of 5.0 and 6.5 GPa of pressure and 1400 to 1600º C of temperature. The sintering conditions were imposed in two ways: directly, or with pre-sintering. The samples were tested by measuring microhardness, wear resistance, densification, and SEM. The results of the tests have shown the possibility of obtaining good quality inserts by sintering both layers of compacted powder.
Authors: Xiao Ming Sang, Run Zeng Wang, Xing Gang Chen, Lei Zhang, Man An, Yi Shen
Abstract: Polyurethane-imide is a novel kind of po lymer with excellent heat-resistant and mechanical properties. This overview embracing microstructure, synthesis and properties of polyurethane-imide is given and provided representative examples to reflect the state of the research for polyurethane-imide. The microstructure includes molecular structure and phase structure. Synthesis of linear PUI and network PUI is given in next and, Mechanical properties, Thermal performance and other properties is also recommended. The shortages of PUI research is imperfection of synthesis and the theoretical analysis, so the prospect of the study on polyurethane-imide is also displayed.
Authors: Peng Xuan Duan, Ye Zhang, Yuan Chao Miao, Ying Li
Abstract: This paper describes replacing natural gypsum with FGD gypsum as cement retarder, the influence on the working performance, compressive strength and admixture adaptability of concretes, which were prepared with fly ash cement, slag cement and ordinary Portland cement. The results indict the FGD gypsum instead of natural gypsum used as cement retarder has little difference on the working performance of concrete and additionally the FGD gypsum has no negative influence on the compressive strength and admixture adaptability of concretes.
Authors: Hai Chuan Wang, Wei Sun, Jian Jun Wang, Jie Lie, Kai Zhong Wang, Jian Wu
Abstract: The paper carries out a study on the composition control of smelting low-carbon low-silicon and high-aluminum cold heading steel SWRCH6A using double-slag process for converter at No.3 General Plant of Steelmaking & Rolling of Masteel, analyzes carbon increasing and silicon increasing status in each smelting process, and studies the mechanical properties, microstructure and inclusion ratings of test steel samples. These results indicate that in smelting process the average carbon increasing △w[C]=0.014%, the average silicon increasing △w[Si]=0.030%, the average content w[Al]s is 0.030% and w[Al]s fluctuates from 0.015% to 0.041%,, but all targets of test steel samples meet the requirements of cold heading steel SWRCH6A.
Authors: Hong Xia Zhang, Xian Xian Wu, Rong Tao, Li Jia Shi, Cheng Yan Zhu, Qi Zheng Li
Abstract: In order to study on the anti-electromagnetic radiation performance of fabrics with silver-plated fibers, five sets of samples with polyester DTY and silver-plated nylon filament were manufactured for the experiment. The anti-electromagnetic radiation property of fabrics was tested with Flange coaxial method. The influence of different silver-plated fiber contents on the anti-electromagnetic radiation performance of fabrics was analyzed in this paper. The experimental results show that when silver-plated fibers are distributed by a network, anti-electromagnetic radiation performance of fabrics is better than that the silver-plated fibers are distributed only along the warp in fabrics. Meanwhile, the anti-electromagnetic radiation performance of fabrics improves as the increasing of the silver-plated fibers content. The anti-electromagnetic radiation performance of fabrics increases slowly when silver-plated fibers content is from 40% to 80%. The shielding effectiveness of fabrics for 10MHz~1000MHz electromagnetic waves increases not obviously when silver-plated fibers content is more than 80%, but that for 3000MHz is still rising. The anti-electromagnetic radiation performance of fabrics is the best when silver-plated fibers content reaches to 100%.
Authors: Lan Sun
Abstract: This paper carries out the research on using the toughening mechanism of phase transition of ZrO2 to inhibit the WC grain and improve the toughness of the hard alloys. WC–ZrO2–8wt%Co hard metals was mixed with 0-2 wt% nano-ZrO2 and prepared by conventional sintering (CS) for 2 h at 1440oC to see whether the addition of ZrO2 could improve densification behavior, the microstructure and mechanical properties of the samples. Experimental results showed that the use of ZrO2 nanoparticles could decrease the relative density because of the worse wetting effects; it could also inhibit the growth of the grains of WC-Co hardmetal to enhance the hardness of the alloy. The fracture toughness of sample has an increasing tendency as a whole because of the phase transition during the sintering process.
Authors: I.O. Ogunleye
Abstract: The thermo-physical properties of some varieties of sawdust and some additives are presented. They are thermal conductivity, heat capacity and specific gravity. The methods of investigation used are Lee’s Disc Apparatus, heat balance and gravimetric method respectively. The sawdust specimens were obtained from six varieties of wood. The additives employed on two typical sawdust samples are cement and silica clay. The values of thermal conductivity range between 0.440 and 0.204 W/m K, and heat capacity between 58,644.08 and 29,584 J/kg K. The highest specific gravity is 0.256 and the least value is 0.107. It was observed that as the clay content increases, specific gravity and the thermal conductivity also increases while the specific heat capacity decreases.
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