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Richard A. Dawe - One of the best experts on this subject based on the ideXlab platform.
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Anisotropy in Pore Structure of porous media
Powder Technology, 1995Co-Authors: Carlos A. Grattoni, Richard A. DaweAbstract:Realistic modelling of porous media is difficult. Different models are proposed depending on the property to be modelled, for example, porosity, permeability, electrical resistivity. Anisotropy is seldom considered. This paper examines the Pore Structure obtained for packs of spheres, with emphasis on the anisotropy. The Structures can be reduced to an equivalent network which demonstrates that anisotropy of the Pore Structure is present even for homogeneous packs of spheres. The influence of anisotropy on the various porous media properties such as permeability, electrical resistivity and convective dispersion is highlighted.
Carlos A. Grattoni - One of the best experts on this subject based on the ideXlab platform.
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Anisotropy in Pore Structure of porous media
Powder Technology, 1995Co-Authors: Carlos A. Grattoni, Richard A. DaweAbstract:Realistic modelling of porous media is difficult. Different models are proposed depending on the property to be modelled, for example, porosity, permeability, electrical resistivity. Anisotropy is seldom considered. This paper examines the Pore Structure obtained for packs of spheres, with emphasis on the anisotropy. The Structures can be reduced to an equivalent network which demonstrates that anisotropy of the Pore Structure is present even for homogeneous packs of spheres. The influence of anisotropy on the various porous media properties such as permeability, electrical resistivity and convective dispersion is highlighted.
Vittorio Ranieri - One of the best experts on this subject based on the ideXlab platform.
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Pore-Structure models of hydraulic conductivity for permeable pavement
Journal of Hydrology, 2011Co-Authors: X. Kuang, G Cui-ying, John J Sansalone, Vittorio RanieriAbstract:Summary Permeable pavement functions as a porous infraStructure interface allowing the infiltration and evaporation of rainfall–runoff while functioning as a relatively smooth load-bearing surface for vehicular transport. Hydraulic conductivity ( k ) of permeable pavement is an important hydraulic property and is a function of the Pore Structure. This study examines k for a cementitious permeable pavement (CPP) through a series of Pore-Structure models. Measurements utilized include hydraulic head as well as total porosity, ( ϕ t ), effective porosity ( ϕ e ), tortuosity ( L e / L ) and Pore size distribution (PSD) indices generated through X-ray tomography (XRT). XRT results indicate that the permeable pavement Pore matrix is hetero-disperse, with high tortuosity and ϕ t ≠ ϕ e . Power law models of k – ϕ t and k – ϕ e relationships are developed for a CPP mix design. Results indicate that the Kruger, Fair-Hatch, Hazen, Slichter, Beyer and Terzaghi models based on simple Pore-Structure indices do not reproduce measured k values. The conventional Kozeny–Carman model (KCM), a more parameterized Pore-Structure model, did not reproduce measured k values. This study proposes a modified KCM utilizing ϕ e , specific surface area (SSA) pe and weighted tortuosity ( L e / L ) w . Results demonstrate that such permeable pavement Pore-Structure parameters with the modified KCM can predict k . The k results are combined with continuous simulation modeling using historical rainfall to provide nomographs examining permeable pavement as a low impact development (LID) infraStructure component.
Shuzo Kanzaki - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Porous Ceramics with Complex Pore Structure by Freeze-Dry Processing
Journal of the American Ceramic Society, 2001Co-Authors: Takayuki Fukasawa, Motohide Ando, Tatsuki Ohji, Shuzo KanzakiAbstract:Porous ceramics with complex Pore Structure were synthesized by a freeze-dry process. Freezing-in of a water-based ceramics slurry was done while controlling the growth direction of the ice. Sublimation marks of the ice were generated by drying under reduced pressure. Porous ceramics having a complex Pore Structure were obtained by sintering the green body: aligned macroscopic open Pores contained microPores in their internal walls. The Pore Structure was substantially affected by the starting slurry concentration and sintering temperature. The Pore formation mechanism is discussed in relation to these effects.
Ingo Heschel - One of the best experts on this subject based on the ideXlab platform.
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control of Pore Structure and size in freeze dried collagen sponges
Journal of Biomedical Materials Research, 2001Co-Authors: H Schoof, Jorn Apel, Ingo Heschel, G RauAbstract:Because of many suitable properties, collagen sponges are used as an acellular implant or a biomaterial in the field of tissue engineering. Generally, the inner three-dimensional Structure of the sponges influences the behavior of cells. To investigate this influence, it is necessary to develop a process to produce sponges with a defined, adjustable, and homogeneous Pore Structure. Collagen sponges can be produced by freeze-drying of collagen suspensions. The Pore Structure of the freeze-dried sponges mirrors the ice-crystal morphology after freezing. In industrial production, the collagen suspensions are solidified under time- and space-dependent freezing conditions, resulting in an inhomogeneous Pore Structure. In this investigation, unidirectional solidification was applied during the freezing process to produce collagen sponges with a homogeneous Pore Structure. Using this technique the entire sample can be solidified under thermally constant freezing conditions. The ice-crystal morphology and size can be adjusted by varying the solute concentration in the collagen suspension. Collagen sponges with a very uniform and defined Pore Structure can be produced. Furthermore, the Pore size can be adjusted between 20-40 microm. The thickness of the sponges prepared during this research was 10 mm.
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control of Pore Structure and size in freeze dried collagen sponges
Journal of Biomedical Materials Research, 2001Co-Authors: H Schoof, Jorn Apel, Ingo HeschelAbstract:Because of many suitable properties, collagen sponges are used as an acellular implant or a biomaterial in the field of tissue engineering. Generally, the inner three-dimensional Structure of the sponges influences the behavior of cells. To investigate this influence, it is necessary to develop a process to produce sponges with a defined, adjustable, and homogeneous Pore Structure. Collagen sponges can be produced by freeze-drying of collagen suspensions. The Pore Structure of the freeze-dried sponges mirrors the ice-crystal morphology after freezing. In industrial production, the collagen suspensions are solidified under time- and space-dependent freezing conditions, resulting in an inhomogeneous Pore Structure. In this investigation, unidirectional solidification was applied during the freezing process to produce collagen sponges with a homogeneous Pore Structure. Using this technique the entire sample can be solidified under thermally constant freezing conditions. The ice-crystal morphology and size can be adjusted by varying the solute concentration in the collagen suspension. Collagen sponges with a very uniform and defined Pore Structure can be produced. Furthermore, the Pore size can be adjusted between 20–40 μm. The thickness of the sponges prepared during this research was 10 mm. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 352–357, 2001
