Topic
Effective porosity
About: Effective porosity is a research topic. Over the lifetime, 1199 publications have been published within this topic receiving 26511 citations.
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TL;DR: In this paper, a one-dimensional model for a well-sorted quartz arenite sequence undergoing diagenesis is presented, where the sedimentary sequence is treated as a saturated porous medium in which pressure solution occurs at individual grain contacts.
Abstract: Pressure solution and the subsequent precipitation of the dissolved material may play an important role in the lithification of sandstones and limestones. This paper presents a one-dimensional model for a well-sorted quartz arenite sequence undergoing diagenesis. The sedimentary sequence is treated as a saturated porous medium in which pressure solution occurs at individual grain contacts. Quartz dissolved at grain contacts precipitates on free surfaces of adjacent grains. This solution-and-precipitation process reduces porosity and forces the migration of pore fluid. Permeability decreases with porosity, hindering fluid migration, and excess fluid pressures are generated. Distributions of porosity, pore-pressure, and fluid-flow rates are given for several sedimentation rates and thermal gradients. Complete reduction of the primary, intergranular porosity was accomplished, in all cases examined, by a depth of 3.5 km.
92 citations
TL;DR: In this article, the authors compared the effectiveness of commercially available sorbents that can be used to amend sand caps to improve their ability to prevent contaminant migration from the sediments into the bioactive zone.
Abstract: In situ capping manages contaminated sediment on-site without creating additional exposure pathways associated with dredging, e.g., sediment resuspension, and potential human exposure during transport, treatment, or disposal of dredged material. Con- taminant mass is not immediately removed in sediment capping, which creates concerns over its long-term effectiveness. Groundwater seepage can also decrease the effectiveness of in situ capping. This study compares the effectiveness of commercially available sorbents that can be used to amend sand caps to improve their ability to prevent contaminant migration from the sediments into the bioactive zone. Amendments evaluated include coke, activated carbon, and organic-rich soil. The properties relevant to advective-dispersive transport through porous media sorption, porosity, dispersivity, and bulk density are measured for each material, and then used as inputs to a numerical model to predict the flux of 2,4,5-polychlorinated biphenyl PCB through a sand cap amended with a thin 1.25-cm sorbent layer. Systems with and without groundwater seepage are considered. Isolation times provided by the sorbent layers increased with increasing sorption strength and capacity activated carboncokesoilsand. The effective porosity, dispersivity, and bulk density of the sorbent layer had little effect on cap performance compared to sorption strength Kf. In the absence of seepage, all sorbents could isolate PCBs in the underlying sediment for times greater than 100 years and would be effective for most cap applications. With groundwater seepage Darcy velocity=1 cm/day, activated carbon was the only sorbent that provided contaminant isolation times greater than 60 years. Long isolation times afforded by sorbent-amended caps allow time for inherently slow natural attenuation processes to further mitigate PCB flux.
91 citations
TL;DR: In this paper, the hydraulic conductivity, effective porosity, and dispersivity of humified bog peat cores were determined using selective-ion probes inserted into the peat 30 cm downgradient from the source.
90 citations
TL;DR: An image analysis system is presented, which allows objectifying in two dimensions the pores' structure and geometry of textile fabrics, that are used to reinforce the abdominal wall or pelvic floor, and the porosity of the textile is measured.
Abstract: The inflammatory and fibrotic intensity of a foreign body reaction largely depends on the porosity of the implanted material. Furthermore, the size of the pore and its geometry define the capability to allow tissue ingrowth. We present an image analysis system, which allows objectifying in two dimensions the pores' structure and geometry of textile fabrics, that are used to reinforce the abdominal wall or pelvic floor. The porosity of the textile is measured at four samples with differences in structure. The porosity decreases markedly if foreign body response is considered, leading to the definition of an "effective porosity". Because of the high stiffness of the polymer fibers the elasticity of textile implants usually result from a deformation of the pores, leading to a marked reduction of the effective porosity if a mechanical stress is applied. Further in vivo studies have to investigate, whether the preservation of a high effective porosity under stress may help to improve biocompatibility of textile implants.
90 citations
TL;DR: In this paper, a series of coupled equations that determine the changes in porosity is outlined and solved for a 2D model domain using a finite element scheme, and the evolution of porosity was examined for two types of porous media: (1) an initially homogeneous system and (2) a heterogeneous system containing high porosity regions that serve initially as preferential flow paths.
89 citations