Papers by Keyword: Pore

Abstract: Porous barium titanate (BaTiO₃, BT) ceramics were prepared by a conventional sintering method using two kinds of BT particles. The relationship between pore structure (porosity and pore size) of BT ceramics and their sensor properties was investigated. Since a piezoelectric d₃₃ constant of BT depends largely on the pore structures, the microstructure control of porous BT ceramics is important to improve the figure-of-merit (g₃₃/ρ). In this study, the maximal piezoelectric g₃₃ constant value of 14.8×10^-3 V·m·N^-1 and the maximal g₃₃/ρ value of 3.14×10³ V·m⁴·N^-1·g^-1 were recorded at a porosity of approximately 23%.

Abstract: Quantitative analysis of soft soil microstructure in unloading levels are made by using scanning electron microscope (SEM) images, IPP and PS of image technology ,which includes image segmentation, pore size measuring and counting, three dimensional simulation of soft soil microstructure, etc. The results indicate that, with the increase of unloading grade, pore number and area of big aperture are in a sharp increase, the corresponding porosity also in ascension, so the deformation of the soil is mainly due to the change of pore; compared with the apparent 3d images of soil under the transverse profile in unloading levels. The results also indicate that, with the increase of unloading grade, pore area of cross section are in a increase.

Abstract: Basically, permeability of ceramic shell mould system play an important role in minimizing the casting defects in most investment casting shell. The mould has to be sufficiently permeable to obtain complete mould filling during casting process. Mould fill can be improved by increasing the open porosity that definitely will increase permeability ceramic shell mould. The elimination of rice husk volatile elements has contributed to the increment of pore structure that provides a great deal of connected pathways through the ceramic shell which directly will increase the permeability of the ceramic shell mould during casting process. Indeed, the rice husk fibers additions increase the permeability after firing by a factor 3 compared to the standard shell mould system (without fiber) that makes its an excellent alternative in producing higher permeable ceramic shell system.

Abstract: Porous materials have been widely used since long ago because they possess important applications: acoustic, thermal insulation, building constructions, biomaterials, aeronautical application, etc. [. The development of porous materials is based on many materials. In a topic are develop the layer of materials by copper electroplating process. It is one of the oldest protective and decorative metallic coatings for steel and other basis metals [. Therefore, intensive studies were carried out to render copper electroplating suitable for different purposes. One of the most important baths used for electroplating copper was the electrolyte bath. The organic (PEG) additives are added copper sulphate plating bath to improve the quality of the porous layer. The electrolyte bath consists of the copper sulphate and PEG particle. Colloidal suspensions are often used as templates to fabricate porous layer material [. So an increment in porosity reduces the mechanical strength of porous materials. The polymer must have good adhesion with the polymer are determine the particle size and amount in electrolyte. Based on this process electroplating was used because the atomic are orderly arrangement and the atomic are packing than other process of porous materials. In the present study we report the preparation of porous layers materials on copper substrate by the electroplating process. The electrolyte solution system used as 35 g·l^-1 Cu from CuSO₄·5H₂O in different conditions (current density and amount of PEG) and characterization of porous layer materials which process the appropriate morphology and chemical properties to be considered as feasible candidates for developing materials.

Abstract: The pore structure of coal rock atYangquan Xinjing mine in Shanxi Province is analyzed with mercury intrusion porosimetry to obtain the specific pore volume data and calculate the fractal dimension of coal pore surface. The pores are divided into macropore, mesopore and micropore according to radius size considering the calculated fractal dimension. The distribution characteristics of pore radius size, specific surface area and specific pore volume of different types are effectively analyzed. The research results show that mesopore surface has significantly fractal characteristics, which features could be discussed quantitatively. The proposed method in this paper has reference significance for studying the sorption and desorption properties, the diffussion and permeation of coalbed methane.

Abstract: The surface topography and properties of coating layer have an important influence on penetration and distribution of the print ink. In this research, the main objective was to investigate the effect of binder on the coating surface topography and characteristics. The surface microstructure was explored in the method of numerical and visual analysis using mercury porosimetry measurment and atomic force microscopy (AFM). The findings indicated that the binder content on the coating surface affected the pore size, depth and distribution of the coated paper surface. The conclusions were drawn that more amount of binder on the coating surface could contribute to improve the coating surface topography and the formation of even pore size and distribution, which was good to the paper surface characteristics and resulted in low roughness, high paper gloss, low ink absorption and high paper surface efficiency.

Abstract: Longitudinal cavities or pipes are usually developed in a metallic slab or billet produced by continuous casting. In the present study, closure behavior of such cavities by side pressing was investigated by finite-element method. Since the contact surface between the dies and the slab was much longer in the longitudinal direction than in the thickness direction, the slab was compressed under the condition of plane-strain deformation. As a result, the effective strain was found to be an indicator for the void closure. The critical value of the effective strain was dependent upon the aspect ratio of the cross section of the cavity, but not upon its size.

Abstract: Three different flaws were detected in a Q345qD hot rolled steel plate by ultrasonic test. The morphologies, chemical compositions and formation causes of these flaws were studied by using metallographic examination, Electron Probe Micros-analyzer (EPMA) and Energy Dispersive X-ray Spectrometer (EDS) analysis. Besides, some corrective measures were proposed to reduce the incidence rate of these detecting flaws.

Abstract: In order to fully mechanized caving face bypass collapse column on safety and high efficiency, this paper do similarity simulation experiment, and obtained experimental result that main type of seepage flow includes finger seepage and surface seepage, the grout enter into around pore and occupy it’s space in grouting pressure. Moisture content of mud and sand medium is lower, grouting process can be regarded as single-phase permeability, analysis on the relation between grouting diffusion radius and other parameters. may know that grouting diffusion radius is increased with the increase of permeability coefficient and grouting pressure and grouting time, and is decreased with the increase of Porosity and grout viscosity.

Abstract: The comparative datas from home and abroad indicate that extra-low permeability of coal seam is the basic reason why the gas outbursts obviously demonstrate three features in Chuandong. Further analysis on the microstructure of coal pore and fracture show that, firstly，the quantity of micro pores is much more than that of macro pores; the total volume of the pores is large while the volume of interconnected pores is small. This is helpful to gas storage but going against gas flow. Secondly, fracture density varys with magnification; there are many short fractures but only a few long fractures; all of the fractures are similar in width and in the form of zigzag; the directivity of fracture extension is irregular. Thirdly, fracture fillings are mainly hard inorganic matters. It is put forward that both pressure sensitive effect and water sensitivity effect exist in the coal seam and they are "double-edged swords" to permeability. In order to increase the permeability, it is necessary to change passive exhausting into active driving, remove gas reservoir and provide the passageway for gas dissipation.