Papers by Keyword: Permeability

Abstract: In this article the possibility of production of composite materials with magnetic texture are discussed. For texturing of magnetic polymer materials the device was made. The W-type hexaferrites were synthesized using a standard ceramic technique. Magnetic materials with a texture based on barium ferrite were obtained. The electromagnetic properties of texture and non texture composites were measured in microwave. It was shown, that imaginary permeability of an isotropic sample 1.3 times more that sample with texture in a frequency range of 0.5 – 4 GHz.

Abstract: The typical characteristic of stoning band coal seams is of multi-layers and low permeability, so fractured vertical well is usually used in the CBM development of this kind of coal seams. As far as the reservoir simulation of vertical fractured CBM wells is concerned, the fracture characterization technique is of great importance. Taking the vertical fractured pilots in F coal measures of Bowen Basin in Australia as an example, this paper will illustrate the application of fracture characterization technique in reservoir simulation. Its highlight is to scientifically characterize the shape of hydraulic fractures and quantitatively describe the reservoir permeability improvement after fracturing through “MULTX” of grid conductivity with Tartan grid model, thereby determining key parameters for the reservoir simulation of fractured vertical wells and providing a scientific basis for establishing CBM development plan and forecasting ultimate recoverable reserves.

Abstract: SIS well is a successful technology for coalbed methane development. In this paper, the drilling and completion technology were introduced systematically on the aspects of optimization design of well profile, drilling equipment, drilling and completion technology of vertical well and horizontal well, and intersection technique of these two wells. Two new well patterns, i.e., commingled well and boat-shape well were also proposed. When application this technology to other areas, some improvement may should be made according to special geological data.

Abstract: The biological toxicity test of luminous bacteria has been widely applied. However, sensitivity of this test needs to be further improved. Cell membranes are bacteria’s first barrier against outside invasions. In this research, permeability of cell membranes will be changed so as to improve toxicity detection sensitivity of vibrio qinghaiensis (Q67). During the cultivation process of Q67, the Ethylene Diamine Tetraacetic Acid (EDTA-Na₂) will be added and the hydrophobic fluorescent probe N-Phenyl-1-Naphthylamine (NPN) will be used to test changes of Q67 cell permeability. In addition, the low temperature centrifuge method will be used to eliminate interferences of residual EDTA of the nutrient medium to the acute toxicity test. The microporous plate method of biological toxicity test will be used to test the acute toxicity of K₂Cr₂Q₇, the phenol and the desmetryn on Q67 before and after the permeability is modified. The results show that: during the cultivation process of Q67, if 2.0 mmol/L EDTA-Na₂ is added, 40.2% of its absorbability to NPN can be improved. What is more, normal growth and bioluminescent property of Q67 will not be affected. EC₅₀ of the K₂Cr₂Q₇, the phenol and the desmetryn to the modified Q67 is 4.39 mg/L, 128.75 mg/L and 145.89 mg/L respectively. Compared with those before the modification, their EC₅₀ reduces 45.70%, 39.77% and 38.61% respectively. Thus, during the cultivation process of Q67, the addition of EDTA-Na₂ can improve its permeability to poisonous substances and enhance the sensitivity of Q67 biological toxicity test.

Abstract: Polymeric membranes are widely used for gas separation purposes but their performance is restricted by the upper bound trade-off discovered by Robeson in 1991. The polymeric membrane can be glassy, rubbery or a blend of these two polymers. This review paper discusses the properties of glassy polymer membranes and their performance in gas separation. The area of improvement for glassy membrane with development of mixed matrix membrane is also highlighted.

Abstract: The lightweight aggregate geopolymer concrete (LWAGC) systems were prepared using a lightweight aggregate (LWA) of different size and grading. The diversity in the LWA size and grading led to various physical properties like oven-dry (OD) density, water absorption and total porosity characteristics for the resultant LWAGCs. These physical properties were significantly affected and controlled thermal behavior of the concretes after exposure to elevated temperature of 800 °C. The results of the mechanical and physical test conducted to the unexposed LWAGCs showed that the OD-density and compressive strength increased as the LWA maximum and minimum size decreased. In contrast, the water absorption and total porosity of the unexposed LWAGC were increased with increasing of the LWA maximum and minimum size. Thus, the lowest OD-density LWAGC possessed the highest water absorption and total porosity which resulted in lowest compressive strength, whereas, it has the minimal strength loss after exposure to the elevated temperature. The water absorption and total porosity of the unexposed LWAGCs were indirectly implies the permeability characteristics of the concretes which is controllers the thermal behavior of the LWAGC at elevated temperatures.

Abstract: The permeability of tight oil reservoir is very low and general perm-plug method always has a big difference. The results can’t reach the test accuracy requirements. This paper measured 26 block rocks of Changqing tight oil reservoir and several typical tight oil reservoirs in CNPC with pulse decay new method. The result shows that the pulse decay permeability measured in the new method and steady-state Klinkenberg-corrected permeability have a good relationship. We drew a figure about the porosity and steady-state Klinkenberg-corrected permeability of these tight oil reservoirs. This research offers a technical support to the tight oil reservoirs about basic data permeability measurement.

Abstract: This paper specifically addresses the effect of changing the constant temperature region of the sintering temperature curve in manufacturing nickel powder capillary structure (wick) on the performance of a flat loop heat pipe (FLHP). The sintering temperature curve is composed of three regions: a region of increasing temperature, a region of constant temperature, and a region of decreasing temperature, with the sintering time and temperature in the region of constant temperature having significant effect on the permeability of the wick. In this study, for wick manufacturing the temperatures in this region tested range from 550°C to 650°C and the time from 30 minutes to 60 minutes. The properties and internal parameters of the wick are measured, and the wick is placed into FLHP for performance testing. Experimental results show that at sintering temperature of 550°C and lasting about 45 minutes, maximum heat load is 200W, minimum thermal resistance is 0.32°C/W, permeability is , porosity is 66%, effective porosity is 3.8and heat flux is around 21W/cm²; related literatures have only reported maximum heat load increase of 25%.

Abstract: In the present work the determination of intrinsic properties in ferromagnetic materials by using magnetic non-destructive techniques is discussed. Barkhausen noise and bulk permeability measurements were used in various steels. The monotonic dependence of the magnetic response on microstructural features was verified.

Abstract: Concepts of flow permeability, flow permeability coefficient and flow porosity were presented to investigate changes of permeability and porosity of mudding weak permeability media with nonlinear flow. Formulas of flow permeability, flow permeability coefficient and flow porosity were presented to study the evolution characteristics. Results show that permeability and porosity of mudding weak permeability media nonlinear flow increase with pressure gradient or hydraulic gradient of nonlinear flow, while permeability and porosity of high permeability media Darcy flow are constant. The results can provide a test and calculation of micro porosity with a new method and can provide engineering safety of mudding weak permeability media nonlinear flow with scientific basis.