Predicting the extent of metabolism using in vitro permeability rate measurements and in silico permeability rate predictions

PubMed Central

Hosey, Chelsea M; Benet, Leslie Z

2015-01-01

The Biopharmaceutics Drug Disposition Classification System (BDDCS) can be utilized to predict drug disposition, including interactions with other drugs and transporter or metabolizing enzyme effects based on the extent of metabolism and solubility of a drug. However, defining the extent of metabolism relies upon clinical data. Drugs exhibiting high passive intestinal permeability rates are extensively metabolized. Therefore, we aimed to determine if in vitro measures of permeability rate or in silico permeability rate predictions could predict the extent of metabolism, to determine a reference compound representing the permeability rate above which compounds would be expected to be extensively metabolized, and to predict the major route of elimination of compounds in a two-tier approach utilizing permeability rate and a previously published model predicting the major route of elimination of parent drug. Twenty-two in vitro permeability rate measurement data sets in Caco-2 and MDCK cell lines and PAMPA were collected from the literature, while in silico permeability rate predictions were calculated using ADMET Predictor™ or VolSurf+. The potential for permeability rate to differentiate between extensively and poorly metabolized compounds was analyzed with receiver operating characteristic curves. Compounds that yielded the highest sensitivity-specificity average were selected as permeability rate reference standards. The major route of elimination of poorly permeable drugs was predicted by our previously published model and the accuracies and predictive values were calculated. The areas under the receiver operating curves were >0.90 for in vitro measures of permeability rate and >0.80 for the VolSurf+ model of permeability rate, indicating they were able to predict the extent of metabolism of compounds. Labetalol and zidovudine predicted greater than 80% of extensively metabolized drugs correctly and greater than 80% of poorly metabolized drugs correctly in Caco

A laboratory study to estimate pore geometric parameters of sandstones using complex conductivity and nuclear magnetic resonance for permeability prediction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osterman, Gordon; Keating, Kristina; Binley, Andrew

Here, we estimate parameters from the Katz and Thompson permeability model using laboratory complex electrical conductivity (CC) and nuclear magnetic resonance (NMR) data to build permeability models parameterized with geophysical measurements. We use the Katz and Thompson model based on the characteristic hydraulic length scale, determined from mercury injection capillary pressure estimates of pore throat size, and the intrinsic formation factor, determined from multisalinity conductivity measurements, for this purpose. Two new permeability models are tested, one based on CC data and another that incorporates CC and NMR data. From measurements made on forty-five sandstone cores collected from fifteen different formations,more » we evaluate how well the CC relaxation time and the NMR transverse relaxation times compare to the characteristic hydraulic length scale and how well the formation factor estimated from CC parameters compares to the intrinsic formation factor. We find: (1) the NMR transverse relaxation time models the characteristic hydraulic length scale more accurately than the CC relaxation time (R 2 of 0.69 and 0.33 and normalized root mean square errors (NRMSE) of 0.16 and 0.21, respectively); (2) the CC estimated formation factor is well correlated with the intrinsic formation factor (NRMSE50.23). We demonstrate that that permeability estimates from the joint-NMR-CC model (NRMSE50.13) compare favorably to estimates from the Katz and Thompson model (NRMSE50.074). Lastly, this model advances the capability of the Katz and Thompson model by employing parameters measureable in the field giving it the potential to more accurately estimate permeability using geophysical measurements than are currently possible.« less

A laboratory study to estimate pore geometric parameters of sandstones using complex conductivity and nuclear magnetic resonance for permeability prediction

DOE PAGES

Osterman, Gordon; Keating, Kristina; Binley, Andrew; ...

2016-03-18

Here, we estimate parameters from the Katz and Thompson permeability model using laboratory complex electrical conductivity (CC) and nuclear magnetic resonance (NMR) data to build permeability models parameterized with geophysical measurements. We use the Katz and Thompson model based on the characteristic hydraulic length scale, determined from mercury injection capillary pressure estimates of pore throat size, and the intrinsic formation factor, determined from multisalinity conductivity measurements, for this purpose. Two new permeability models are tested, one based on CC data and another that incorporates CC and NMR data. From measurements made on forty-five sandstone cores collected from fifteen different formations,more » we evaluate how well the CC relaxation time and the NMR transverse relaxation times compare to the characteristic hydraulic length scale and how well the formation factor estimated from CC parameters compares to the intrinsic formation factor. We find: (1) the NMR transverse relaxation time models the characteristic hydraulic length scale more accurately than the CC relaxation time (R 2 of 0.69 and 0.33 and normalized root mean square errors (NRMSE) of 0.16 and 0.21, respectively); (2) the CC estimated formation factor is well correlated with the intrinsic formation factor (NRMSE50.23). We demonstrate that that permeability estimates from the joint-NMR-CC model (NRMSE50.13) compare favorably to estimates from the Katz and Thompson model (NRMSE50.074). Lastly, this model advances the capability of the Katz and Thompson model by employing parameters measureable in the field giving it the potential to more accurately estimate permeability using geophysical measurements than are currently possible.« less

Instrumentation for Measurement of Gas Permeability of Polymeric Membranes

NASA Technical Reports Server (NTRS)

Upchurch, Billy T.; Wood, George M.; Brown, Kenneth G.; Burns, Karen S.

1993-01-01

A mass spectrometric 'Dynamic Delta' method for the measurement of gas permeability of polymeric membranes has been developed. The method is universally applicable for measurement of the permeability of any gas through polymeric membrane materials. The usual large sample size of more than 100 square centimeters required for other methods is not necessary for this new method which requires a size less than one square centimeter. The new method should fulfill requirements and find applicability for industrial materials such as food packaging, contact lenses and other commercial materials where gas permeability or permselectivity properties are important.

Experimental Measurements of Permeability Evolution along Faults during Progressive Slip

NASA Astrophysics Data System (ADS)

Strutz, M.; Mitchell, T. M.; Renner, J.

2010-12-01

Little is currently known about the dynamic changes in fault-parallel permeability along rough faults during progressive slip. With increasing slip, asperities are worn to produce gouge which can dramatically reduce along fault permeability within the slip zone. However, faults can have a range of roughness which can affect both the porosity and both the amount and distribution of fault wear material produced in the slipping zone during the early stages of fault evolution. In this novel study we investigate experimentally the evolution of permeability along a fault plane in granite sawcut sliding blocks with a variety of intial roughnesses in a triaxial apparatus. Drillholes in the samples allow the permeability to be measured along the fault plane during loading and subsequent fault displacement. Use of the pore pressure oscillation technique (PPO) allows the continuous measurement of permeability without having to stop loading. To achieve a range of intial starting roughnesses, faults sawcut surfaces were prepared using a variety of corundum powders ranging from 10 µm to 220 µm, and for coarser roughness were air-blasted with glass beads up to 800µm in size. Fault roughness has been quantified with a laser profileometer. During sliding, we measure the acoustic emissions in order to detect grain cracking and asperity shearing which may relate to both the mechanical and permeability data. Permeability shows relative reductions of up to over 4 orders of magnitude during stable sliding as asperities are sheared to produce a fine fault gouge. This variation in permeability is greatest for the roughest faults, reducing as fault roughness decreases. The onset of permeability reduction is contemporaneous with a dramatic reduction in the amount of detected acoustic emissions, where a continuous layer of fault gouge has developed. The amount of fault gouge produced is related to the initial roughness, with the rough faults showing larger fault gouge layers at the end of

Reanalysis of in situ permeability measurements in the Barbados décollement

USGS Publications Warehouse

Bekins, B.A.; Matmon, D.; Screaton, E.J.; Brown, K.M.

2011-01-01

A cased and sealed borehole in the Northern Barbados accretionary complex was the site of the first attempts to measure permeability in situ along a plate boundary décollement. Three separate efforts at Hole 949C yielded permeability estimates for the décollement spanning four orders of magnitude. An analysis of problems encountered during installation of the casing and seals provides insights into how the borehole conditions may have led to the wide range of results. During the installation, sediments from the surrounding formation repeatedly intruded into the borehole and casing. Stress analysis shows that the weak sediments were deforming plastically and the radial and tangential stresses around the borehole were significantly lower than lithostatic. This perturbed stress state may explain why the test pressure records showed indications of hydrofracture at pressures below lithostatic, and permeabilities rose rapidly as the estimated effective stress dropped below 0.8 MPa. Even after the borehole was sealed, the plastic deformation of the formation and relatively large gap of the wire wrapped screen allowed sediment to flow into the casing. Force equilibrium calculations predict sediment would have filled the borehole to 10 cm above the top of the screen by the time slug tests were conducted 1.5 years after the borehole was sealed. Reanalysis of the slug test results with these conditions yields several orders of magnitude higher permeability estimates than the original analysis which assumed an open casing. Overall the results based on only the tests with no sign of hydrofracture yield a permeability range of 10−14–10−15 m2 and a rate of increase in permeability with decreasing effective stress consistent with laboratory tests on samples from the décollement zone.

Hydraulic and acoustic properties of the active Alpine Fault, New Zealand: Laboratory measurements on DFDP-1 drill core

NASA Astrophysics Data System (ADS)

Carpenter, B. M.; Kitajima, H.; Sutherland, R.; Townend, J.; Toy, V. G.; Saffer, D. M.

2014-03-01

We report on laboratory measurements of permeability and elastic wavespeed for a suite of samples obtained by drilling across the active Alpine Fault on the South Island of New Zealand, as part of the first phase of the Deep Fault Drilling Project (DFDP-1). We find that clay-rich cataclasite and principal slip zone (PSZ) samples exhibit low permeabilities (⩽10-18 m), and that the permeability of hanging-wall cataclasites increases (from c. 10-18 m to 10-15 m) with distance from the fault. Additionally, the PSZ exhibits a markedly lower P-wave velocity and Young's modulus relative to the wall rocks. Our laboratory data are in good agreement with in situ wireline logging measurements and are consistent with the identification of an alteration zone surrounding the PSZ defined by observations of core samples. The properties of this zone and the low permeability of the PSZ likely govern transient hydrologic processes during earthquake slip, including thermal pressurization and dilatancy strengthening.

Laboratory measurements of shock propagation through spherical cavities in an optically accessible polymer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chojnicki, Kirsten; Cooper, Marcia A.; Guo, Shuyue

Pore-scale aperture effects on flow in pore networks was studied in the laboratory to provide a parameterization for use in transport models. Four cases were considered: regular and irregular pillar/pore alignment with and without an aperture. The velocity field of each case was measured and simulated, providing quantitatively comparable results. Two aperture effect parameterizations were considered: permeability and transmission. Permeability values varied by an order of magnitude between the cases with and without apertures. However, transmission did not correlate with permeability. Despite having much greater permeability the regular aperture case permitted less transmission than the regular case. Moreover, both irregularmore » cases had greater transmission than the regular cases, a difference not supported by the permeabilities. Overall, these findings suggest that pore-scale aperture effects on flow though a pore-network may not be adequately captured by properties such as permeability for applications that are interested in determining particle transport volume and timing.« less

Estimation of the superhigh-frequency magnetic permeability of alsifer from the measured permeability of composites

NASA Astrophysics Data System (ADS)

Starostenko, S. N.; Rozanov, K. N.; Shiryaev, A. O.; Lagar'kov, A. N.; Shalygin, A. N.

2017-11-01

The magnetic permeability of alsifer was restored from the frequency dependences of the dielectric and magnetic permeabilities of powder alsifer (AlSiFe alloy)-wax matrix composites. The permeabilities were measured using the coaxial line technique within a frequency range of 0.05-20 GHz. The effect of the concentration, shape, and size of powder particles on the microwave magnetic properties of composites was considered. A good agreement between the measurement results and the Maxwell-Garnett formula generalized with consideration for the particle shape, the percolation threshold, and the skin-effect was obtained. The found sizes of particles agreed with electron microscopy and granulometry data. Both the frequency and the ferromagnetic resonance line figure of merit (FOM) for lamellar particles proved to be higher than for spherical ones. Alsifer powders were shown to be promising fillers for radioabsorbing materials.

Permeability Measurements of Rock Samples from Conduit Drilling at Unzen Volcano, Japan

NASA Astrophysics Data System (ADS)

Watanabe, T.; Shimizu, Y.; Noguchi, S.; Nakada, S.

2006-12-01

The last eruption of Unzen Volcano (1990-1995) was effusive to form lava domes, though magmas at depths are estimated to have contained volatile materials enough to cause explosive eruptions [e.g., Sato et al., 1995]. Most of volatile materials should have escaped from ascending magmas. The escape of gas is controlled by permeability of magmas and country rocks. Unzen Scientific Drilling Project sampled both the latest conduit and its country rock (USDP-4). In order to understand degassing processes, we have measured the permeability of these rock samples. Four cube samples with edges of 25 mm were cut from USDP-4 cores C1, C12 (country rock), C13 and C14 (conduit). Sample C1 is considered as Old Unzen Lava, and Sample C12 volcanic breccia. The transient pulse method was employed to measure the permeability. It applies a step of the fluid pressure difference across a specimen, and measures the decay rate of the fluid pressure difference. This method can be applied to samples with very low permeability, since it determines the permeability without measuring the fluid flux. Nitrogen gas was used as a pore fluid. Our permeametry system is built in a pressure vessel, and the confining pressure and the pore fluid pressure can be controlled independently. The temperature of the measurement system is kept constant within 0.1 degree. The temperature control and the background leak rate limit the measurable permeability to be higher than 10^{-20} m2. Measurements were first conducted under the atmospheric pressure. The permeability in a rock sample varies with the direction by a factor less than 5. Sample C1 has the lowest permeability (10^{-19} m2), and Sample C12 the highest value (10^{-17 m2). The permeability of C13 and C14 is of the order of 10^{- 18} m2. Though only a trace of vesicles can be seen in conduit samples, the interconnection is still maintained. The pressure dependence of the permeability is now investigated up to 50 MPa. The permeability of C13 and C14

Defining clogging potential for permeable concrete.

PubMed

Kia, Alalea; Wong, Hong S; Cheeseman, Christopher R

2018-08-15

Permeable concrete is used to reduce urban flooding as it allows water to flow through normally impermeable infrastructure. It is prone to clogging by particulate matter and predicting the long-term performance of permeable concrete is challenging as there is currently no reliable means of characterising clogging potential. This paper reports on the performance of a range of laboratory-prepared and commercial permeable concretes, close packed glass spheres and aggregate particles of varying size, exposed to different clogging methods to understand this phenomena. New methods were developed to study clogging and define clogging potential. The tests involved applying flowing water containing sand and/or clay in cycles, and measuring the change in permeability. Substantial permeability reductions were observed in all samples, particularly when exposed to sand and clay simultaneously. Three methods were used to define clogging potential based on measuring the initial permeability decay, half-life cycle and number of cycles to full clogging. We show for the first time strong linear correlations between these parameters for a wide range of samples, indicating their use for service-life prediction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Asphalt permeability testing between laboratories.

DOT National Transportation Integrated Search

2005-01-01

Problems with water penetrating into pavement were observed with the early coarse asphalt Superpave mixtures. There was justified concern that water would cause early deterioration; therefore, an effort was made to investigate the permeability proble...

Experimental investigation on the coupled effect of effective stress and gas slippage on the permeability of shale.

PubMed

Yang, Diansen; Wang, Wei; Chen, Weizhong; Wang, Shugang; Wang, Xiaoqiong

2017-03-17

Permeability is one of the most important parameters to evaluate gas production in shale reservoirs. Because shale permeability is extremely low, gas is often used in the laboratory to measure permeability. However, the measured apparent gas permeability is higher than the intrinsic permeability due to the gas slippage effect, which could be even more dominant for materials with nanopores. Increasing gas pressure during tests reduces gas slippage effect, but it also decreases the effective stress which in turn influences the permeability. The coupled effect of gas slippage and effective stress on shale permeability remains unclear. Here we perform laboratory experiments on Longmaxi shale specimens to explore the coupled effect. We use the pressure transient method to measure permeability under different stress and pressure conditions. Our results reveal that the apparent measured permeability is controlled by these two competing effects. With increasing gas pressure, there exists a pressure threshold at which the dominant effect on permeability switches from gas slippage to effective stress. Based on the Klinkenberg model, we propose a new conceptual model that incorporates both competing effects. Combining microstructure analysis, we further discuss the roles of stress, gas pressure and water contents on gas permeability of shale.

A new simplified method for measuring the permeability characteristics of highly porous media

NASA Astrophysics Data System (ADS)

Qin, Yinghong; Zhang, Mingyi; Mei, Guoxiong

2018-07-01

Fluid flow through highly porous media is important in a variety of science and technology fields, including hydrology, chemical engineering, convections in porous media, and others. While many methods have been available to measure the permeability of tight solid materials, such as concrete and rock, the technique for measuring the permeability of highly porous media is limited (such as gravel, aggregated soils, and crushed rock). This study proposes a new simplified method for measuring the permeability of highly porous media with a permeability of 10-8-10-4 m2, using a Venturi tube to gauge the gas flowing rate through the sample. Using crushed rocks and glass beads as the test media, we measure the permeability and inertial resistance factor of six types of single-size aggregate columns. We compare the testing results with the published permeability and inertial resistance factor of crushed rock and of glass beads. We found that in a log-log graph, the permeability and inertial resistance factor of a single-size aggregate heap increases linearly with the mean diameter of the aggregate. We speculate that the proposed simplified method is suitable to efficiently test the permeability and inertial resistance factor of a variety of porous media with an intrinsic permeability of 10-8-10-4 m2.

Apparatus for providing directional permeability measurements in subterranean earth formations

DOEpatents

Shuck, Lowell Z.

1977-01-01

Directional permeability measurements are provided in a subterranean earth formation by injecting a high-pressure gas from a wellbore into the earth formation in various azimuthal directions with the direction having the largest pressure drop being indicative of the maximum permeability direction. These measurements are provided by employing an inflatable boot containing a plurality of conduits in registry with a like plurality of apertures penetrating the housing at circumferentially spaced-apart locations. These conduits are, in turn, coupled through a valved manifold to a source of pressurized gas so that the high-pressure gas may be selectively directed through any conduit into the earth formation defining the bore with the resulting difference in the pressure drop through the various conduits providing the permeability measurements.

Time-Dependent Influence of Cell Membrane Permeability on MR Diffusion Measurements

PubMed Central

Li, Hua; Jiang, Xiaoyu; Xie, Jingping; McIntyre, J. Oliver; Gore, John C.; Xu, Junzhong

2015-01-01

Purpose To investigate the influence of cell membrane permeability on diffusion measurements over a broad range of diffusion times. Methods Human myelogenous leukemia K562 cells were cultured and treated with saponin to selectively alter cell membrane permeability, resulting in a broad physiologically relevant range from 0.011 μm/ms to 0.044 μm/ms. Apparent diffusion coefficient (ADC) values were acquired with the effective diffusion time (Δeff) ranging from 0.42 to 3000 ms. Cosine-modulated oscillating gradient spin echo (OGSE) measurements were performed to achieve short Δeff from 0.42 to 5 ms, while stimulated echo acquisitions (STEAM) were used to achieve long Δeff from 11 to 2999 ms. Computer simulations were also performed to support the experimental results. Results Both computer simulations and experiments in vitro showed that the influence of membrane permeability on diffusion MR measurements is highly dependent on the choice of diffusion time, and it is negligible only when the diffusion time is at least one order of magnitude smaller than the intracellular exchange lifetime. Conclusion The influence of cell membrane permeability on the measured ADCs is negligible in OGSE measurements at moderately high frequencies. By contrast, cell membrane permeability has a significant influence on ADC and quantitative diffusion measurements at low frequencies such as those sampled using conventional pulsed gradient methods. PMID:26096552

Experimental investigation on the coupled effect of effective stress and gas slippage on the permeability of shale

PubMed Central

Yang, Diansen; Wang, Wei; Chen, Weizhong; Wang, Shugang; Wang, Xiaoqiong

2017-01-01

Permeability is one of the most important parameters to evaluate gas production in shale reservoirs. Because shale permeability is extremely low, gas is often used in the laboratory to measure permeability. However, the measured apparent gas permeability is higher than the intrinsic permeability due to the gas slippage effect, which could be even more dominant for materials with nanopores. Increasing gas pressure during tests reduces gas slippage effect, but it also decreases the effective stress which in turn influences the permeability. The coupled effect of gas slippage and effective stress on shale permeability remains unclear. Here we perform laboratory experiments on Longmaxi shale specimens to explore the coupled effect. We use the pressure transient method to measure permeability under different stress and pressure conditions. Our results reveal that the apparent measured permeability is controlled by these two competing effects. With increasing gas pressure, there exists a pressure threshold at which the dominant effect on permeability switches from gas slippage to effective stress. Based on the Klinkenberg model, we propose a new conceptual model that incorporates both competing effects. Combining microstructure analysis, we further discuss the roles of stress, gas pressure and water contents on gas permeability of shale. PMID:28304395

Permeability Estimation Directly From Logging-While-Drilling Induced Polarization Data

NASA Astrophysics Data System (ADS)

Fiandaca, G.; Maurya, P. K.; Balbarini, N.; Hördt, A.; Christiansen, A. V.; Foged, N.; Bjerg, P. L.; Auken, E.

2018-04-01

In this study, we present the prediction of permeability from time domain spectral induced polarization (IP) data, measured in boreholes on undisturbed formations using the El-log logging-while-drilling technique. We collected El-log data and hydraulic properties on unconsolidated Quaternary and Miocene deposits in boreholes at three locations at a field site in Denmark, characterized by different electrical water conductivity and chemistry. The high vertical resolution of the El-log technique matches the lithological variability at the site, minimizing ambiguity in the interpretation originating from resolution issues. The permeability values were computed from IP data using a laboratory-derived empirical relationship presented in a recent study for saturated unconsolidated sediments, without any further calibration. A very good correlation, within 1 order of magnitude, was found between the IP-derived permeability estimates and those derived using grain size analyses and slug tests, with similar depth trends and permeability contrasts. Furthermore, the effect of water conductivity on the IP-derived permeability estimations was found negligible in comparison to the permeability uncertainties estimated from the inversion and the laboratory-derived empirical relationship.

Development and proposed implementation of a field permeability test for a asphalt concrete.

DOT National Transportation Integrated Search

2001-07-01

The objectives of this study were as follows: : 1) To review research performed by others and determine the state-of-the-art of field permeability measurements; : 2) To review current laboratory permeability testing devices and their testing procedur...

Continuous permeability measurements record healing inside the Wenchuan earthquake fault zone.

PubMed

Xue, Lian; Li, Hai-Bing; Brodsky, Emily E; Xu, Zhi-Qing; Kano, Yasuyuki; Wang, Huan; Mori, James J; Si, Jia-Liang; Pei, Jun-Ling; Zhang, Wei; Yang, Guang; Sun, Zhi-Ming; Huang, Yao

2013-06-28

Permeability controls fluid flow in fault zones and is a proxy for rock damage after an earthquake. We used the tidal response of water level in a deep borehole to track permeability for 18 months in the damage zone of the causative fault of the 2008 moment magnitude 7.9 Wenchuan earthquake. The unusually high measured hydraulic diffusivity of 2.4 × 10(-2) square meters per second implies a major role for water circulation in the fault zone. For most of the observation period, the permeability decreased rapidly as the fault healed. The trend was interrupted by abrupt permeability increases attributable to shaking from remote earthquakes. These direct measurements of the fault zone reveal a process of punctuated recovery as healing and damage interact in the aftermath of a major earthquake.

Gas diffusivity and permeability through the firn column at Summit, Greenland: measurements and comparison to microstructural properties

NASA Astrophysics Data System (ADS)

Adolph, A. C.; Albert, M. R.

2014-02-01

The physical structure of polar firn plays a key role in the mechanisms by which glaciers and ice sheets preserve a natural archive of past atmospheric composition. This study presents the first measurements of gas diffusivity and permeability along with microstructural information measured from the near-surface firn through the firn column to pore close-off. Both fine- and coarse-grained firn from Summit, Greenland are included in this study to investigate the variability in firn caused by seasonal and storm-event layering. Our measurements reveal that the porosity of firn (derived from density) is insufficient to describe the full profiles of diffusivity and permeability, particularly at porosity values above 0.5. Thus, even a model that could perfectly predict the density profile would be insufficient for application to issues involving gas transport. The measured diffusivity profile presented here is compared to two diffusivity profiles modeled from firn air measurements from Summit. Because of differences in scale and in firn processes between the true field situation, firn modeling, and laboratory measurements, the results follow a similar overall pattern but do not align; our results constitute a lower bound on diffusive transport. In comparing our measurements of both diffusivity and permeability to previous parameterizations from numerical 3-D lattice-Boltzmann modeling, it is evident that the previous relationships to porosity are likely site-specific. We present parameterizations relating diffusivity and permeability to porosity as a possible tool, though use of direct measurements would be far more accurate when feasible. The relationships between gas transport properties and microstructural properties are characterized and compared to existing relationships for general porous media, specifically the Katz-Thompson (KT), Kozeny-Carman (KC), and Archie's law approximations. While those approximations can capture the general trend of gas transport

Permeability and seismic velocity and their anisotropy across the Alpine Fault, New Zealand: An insight from laboratory measurements on core from the Deep Fault Drilling Project phase 1 (DFDP-1)

NASA Astrophysics Data System (ADS)

Allen, M. J.; Tatham, D.; Faulkner, D. R.; Mariani, E.; Boulton, C.

2017-08-01

The Alpine Fault, a transpressional plate boundary between the Australian and Pacific plates, is known to rupture quasiperiodically with large magnitude earthquakes (Mw 8). The hydraulic and elastic properties of fault zones are thought to vary over the seismic cycle, influencing the nature and style of earthquake rupture and associated processes. We present a suite of laboratory permeability and P (Vp) and S (Vs) wave velocity measurements performed on fault lithologies recovered during the first phase of the Deep Fault Drilling Project (DFDP-1), which sampled principal slip zone (PSZ) gouges, cataclasites, and fractured ultramylonites, with all recovered lithologies overprinted by abundant secondary mineralization, recording enhanced fluid-rock interaction. Core material was tested in three orthogonal directions, orientated relative to the down-core axis and, when present, foliation. Measurements were conducted with pore pressure (H2O) held at 5 MPa over an effective pressure (Peff) range of 5-105 MPa. Permeabilities and seismic velocities decrease with proximity to the PSZ with permeabilities ranging from 10-17 to 10-21 m2 and Vp and Vs ranging from 4400 to 5900 m/s in the ultramylonites/cataclasites and 3900 to 4200 m/s at the PSZ. In comparison with intact country rock protoliths, the highly variable cataclastic structures and secondary phyllosilicates and carbonates have resulted in an overall reduction in permeability and seismic wave velocity, as well as a reduction in anisotropy within the fault core. These results concur with other similar studies on other mature, tectonic faults in their interseismic period.

13C Mannitol as a Novel Biomarker for Measurement of Intestinal Permeability

PubMed Central

Grover, Madhusudan; Camilleri, Michael; Hines, Jolaine; Burton, Duane; Ryks, Michael; Wadhwa, Akhilesh; Sundt, Wendy; Dyer, Roy; Singh, Ravinder J.

2016-01-01

Background Gastrointestinal (GI) and non-GI disorders are associated with altered intestinal permeability, which can be measured in vivo by urinary excretion after oral lactulose and mannitol ingestion. Inadvertent dietary consumption of 12Carbon (12C, regular) mannitol in food or from other sources may interfere with the test’s interpretation. 13Carbon (13C) constitutes 1% of carbon in nature and 13C mannitol is a stable isotope. Our aim was to determine performance of 13C mannitol for measurement of intestinal permeability. Methods Ten healthy volunteers underwent intestinal permeability assay using co-administered 12C mannitol, 13C mannitol and lactulose, followed by timed urine collections. Urinary sugar concentrations were measured using tandem high performance liquid chromatography-mass spectrometry. Key Results We found that 13C mannitol can be distinguishable from 12C mannitol on tandem mass spectrometry. Additionally, 13C mannitol had ~20-fold lower baseline contamination compared to 12C mannitol. We describe here the 13C mannitol assay method for measurement of intestinal permeability. Conclusions & Inferences In conclusion, 13C mannitol is superior to 12C mannitol for measurement of intestinal permeability. It avoids issues with baseline contamination and erratic excretions during the testing period. PMID:26914765

(13) C mannitol as a novel biomarker for measurement of intestinal permeability.

PubMed

Grover, M; Camilleri, M; Hines, J; Burton, D; Ryks, M; Wadhwa, A; Sundt, W; Dyer, R; Singh, R J

2016-07-01

Gastrointestinal (GI) and non-GI disorders are associated with altered intestinal permeability, which can be measured in vivo by urinary excretion after oral lactulose and mannitol ingestion. Inadvertent dietary consumption of (12) Carbon ((12) C, regular) mannitol in food or from other sources may interfere with the test's interpretation. (13) Carbon ((13) C) constitutes 1% of carbon in nature and (13) C mannitol is a stable isotope. Our aim was to determine the performance of (13) C mannitol for measurement of intestinal permeability. Ten healthy volunteers underwent intestinal permeability assay using coadministered (12) C mannitol, (13) C mannitol and lactulose, followed by timed urine collections. Urinary sugar concentrations were measured using tandem high performance liquid chromatography-mass spectrometry. We found that (13) C mannitol can be distinguishable from (12) C mannitol on tandem mass spectrometry. In addition, (13) C mannitol had ~20-fold lower baseline contamination compared to (12) C mannitol. We describe here the (13) C mannitol assay method for the measurement of intestinal permeability. In conclusion, (13) C mannitol is superior to (12) C mannitol for measurement of intestinal permeability. It avoids issues with baseline contamination and erratic excretions during the testing period. © 2016 John Wiley & Sons Ltd.

Theoretical Evaluation of the Transient Response of Constant Head and Constant Flow-Rate Permeability Tests

USGS Publications Warehouse

Zhang, M.; Takahashi, M.; Morin, R.H.; Esaki, T.

1998-01-01

A theoretical analysis is presented that compares the response characteristics of the constant head and the constant flowrate (flow pump) laboratory techniques for quantifying the hydraulic properties of geologic materials having permeabilities less than 10-10 m/s. Rigorous analytical solutions that describe the transient distributions of hydraulic gradient within a specimen are developed, and equations are derived for each method. Expressions simulating the inflow and outflow rates across the specimen boundaries during a constant-head permeability test are also presented. These solutions illustrate the advantages and disadvantages of each method, including insights into measurement accuracy and the validity of using Darcy's law under certain conditions. The resulting observations offer practical considerations in the selection of an appropriate laboratory test method for the reliable measurement of permeability in low-permeability geologic materials.

Laboratory Investigation of Coal Deformation Behavior and Its Influence on Permeability Evolution During Methane Displacement by CO2

NASA Astrophysics Data System (ADS)

Fan, Jingjing; Feng, Ruimin; Wang, Jin; Wang, Yanbin

2017-07-01

Geological sequestration of CO2 in coal seams is of significant interest to both academia and industry. A thorough laboratory investigation of mechanical and flow behaviors is crucial for understanding the complex response of coalbeds to CO2 injection-enhanced coalbed methane recovery (CO2-ECBM) operation. In this work, systematic experiments were carried out on cylindrical coal core specimens under different uniform confining stresses. The coal deformation caused by variations in effective stress as well as the sorption-induced matrix swelling/shrinkage was monitored. The competitive gas sorption characteristics and permeability evolution during the process of methane displacement by CO2 were also investigated. The measured volumetric strain results indicate that sorption-induced strain is the dominant factor in the coal deformation. The relationship between the volumetric strain and the adsorbed gas volume has been revealed to be a linear function. Experimental results obtained under different stress conditions suggest that higher confining stress suppresses the increase in both volumetric strain and the adsorbed gas volume. Furthermore, both methane displacement and CO2 injection are reduced when applying higher confining stresses. In addition, the permeability enhancement is heavily suppressed at higher confining stress. At a certain confining stress, a characteristic "U-shaped" trend of permeability is presented as a function of decreasing pore pressure. This study contributes to the understanding of coal deformation and its impact on permeability evolution under uniformly stressed condition, which has practical significance for CO2 sequestration and CO2-ECBM operation in the Qinshui basin.

Microscale diffusion measurements and simulation of a scaffold with a permeable strut.

PubMed

Lee, Seung Youl; Lee, Byung Ryong; Lee, Jongwan; Kim, Seongjun; Kim, Jung Kyung; Jeong, Young Hun; Jin, Songwan

2013-10-10

Electrospun nanofibrous structures provide good performance to scaffolds in tissue engineering. We measured the local diffusion coefficients of 3-kDa FITC-dextran in line patterns of electrospun nanofibrous structures fabricated by the direct-write electrospinning (DWES) technique using the fluorescence recovery after photobleaching (FRAP) method. No significant differences were detected between DWES line patterns fabricated with polymer supplied at flow rates of 0.1 and 0.5 mL/h. The oxygen diffusion coefficients of samples were estimated to be ~92%-94% of the oxygen diffusion coefficient in water based on the measured diffusion coefficient of 3-kDa FITC-dextran. We also simulated cell growth and distribution within spatially patterned scaffolds with struts consisting of either oxygen-permeable or non-permeable material. The permeable strut scaffolds exhibited enhanced cell growth. Saturated depths at which cells could grow to confluence were 15% deeper for the permeable strut scaffolds than for the non-permeable strut scaffold.

Porometric properties of siliciclastic marine sand: A comparison of traditional laboratory measurements with image analysis and effective medium modeling

USGS Publications Warehouse

Reed, A.H.; Briggs, K.B.; Lavoie, D.L.

2002-01-01

During the 1999 sediment acoustics experiment (SAX99), porometric properties were measured and predicted for a well sorted, medium sand using standard laboratory geotechnical methods and image analysis of resin-impregnated sediments. Sediment porosity measured by laboratory water-weight-loss methods (0.372 ?? 0.0073 for mean ??1 standard deviation) is 0.026 lower than determined by microscopic image analysis of resin-impregnated sediments (0.398 ?? 0.029). Values of intrinsic permeability (m2) determined from constant-head permeameter measurements (3.29 ?? 10-11 ?? 0.60 ?? 10-11) and by microscopic image analysis coupled with effective medium theory modeling (2.78 ?? 10-11 ?? 1.01 ?? 10-11) are nearly identical within measurement error. The mean value of tortuosity factor measured from images is 1.49 ?? 0.09, which is in agreement with tortuosity factor determined from electrical resistivity measurements. Slight heterogeneity and anisotropy are apparent in the top three centimeters of sediment as determined by image-based porometric property measurements. However, the overall similarity for both measured and predicted values of porosity and permeability among and within SAX99 sites indicates sediments are primarily homogeneous and isotropic and pore size distributions are fairly uniform. The results indicate that an effective medium theory technique and two-dimensional image analysis accurately predicts bulk permeability in resin-impregnated sands.

Quantifying Evaporation in a Permeable Pavement System ...

EPA Pesticide Factsheets

Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. The U.S. Environmental Protection Agency (USEPA) constructed a 0.4-ha parking lot in Edison, NJ, that incorporated three different permeable pavement types in the parking lanes – permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA). An impermeable liner installed 0.4 m below the driving surface in four 11.6-m by 4.74-m sections per each pavement type captures all infiltrating water and routes it to collection tanks that can contain events up to 38 mm. Each section has a design impervious area to permeable pavement area ratio of 0.66:1. Pressure transducers installed in the underdrain collection tanks measured water level for 24 months. Level was converted to volume using depth-to-volume ratios for individual collection tanks. Using a water balance approach, the measured infiltrate volume was compared to rainfall volume on an event-basis to determine the rainfall retained in the pavement strata and underlying aggregate. Evaporation since the previous event created additional storage in the pavement and aggregate layers. Events were divided into three groups based on antecedent dry period (ADP) and three, four-month categories of potential e

The permeability of fractured rocks in pressurised volcanic and geothermal systems.

PubMed

Lamur, A; Kendrick, J E; Eggertsson, G H; Wall, R J; Ashworth, J D; Lavallée, Y

2017-07-21

The connectivity of rocks' porous structure and the presence of fractures influence the transfer of fluids in the Earth's crust. Here, we employed laboratory experiments to measure the influence of macro-fractures and effective pressure on the permeability of volcanic rocks with a wide range of initial porosities (1-41 vol. %) comprised of both vesicles and micro-cracks. We used a hand-held permeameter and hydrostatic cell to measure the permeability of intact rock cores at effective pressures up to 30 MPa; we then induced a macro-fracture to each sample using Brazilian tensile tests and measured the permeability of these macro-fractured rocks again. We show that intact rock permeability increases non-linearly with increasing porosity and decreases with increasing effective pressure due to compactional closure of micro-fractures. Imparting a macro-fracture both increases the permeability of rocks and their sensitivity to effective pressure. The magnitude of permeability increase induced by the macro-fracture is more significant for dense rocks. We finally provide a general equation to estimate the permeability of intact and fractured rocks, forming a basis to constrain fluid flow in volcanic and geothermal systems.

Field-scale permeability and temperature of volcanic crust from borehole data: Campi Flegrei, southern Italy

NASA Astrophysics Data System (ADS)

Carlino, Stefano; Piochi, Monica; Tramelli, Anna; Mormone, Angela; Montanaro, Cristian; Scheu, Bettina; Klaus, Mayer

2018-05-01

We report combined measurements of petrophysical and geophysical parameters for a 501-m deep borehole located on the eastern side of the active Campi Flegrei caldera (Southern Italy), namely (i) in situ permeability by pumping tests, (ii) laboratory-determined permeability of the drill core, and (iii) thermal gradients by distributed fiber optic and thermocouple sensors. The borehole was drilled during the Campi Flegrei Deep Drilling Project (in the framework of the International Continental Scientific Drilling Program) and gives information on the least explored caldera sector down to pre-caldera deposits. The results allow comparative assessment of permeability obtained from both borehole (at depth between 422 a 501 m) and laboratory tests (on a core sampled at the same depth) for permeability values of 10-13 m2 (borehole test) and 10-15 m2 (laboratory test) confirm the scale-dependency of permeability at this site. Additional geochemical and petrophysical determinations (porosity, density, chemistry, mineralogy and texture), together with gas flow measurements, corroborate the hypothesis that discrepancies in the permeability values are likely related to in-situ fracturing. The continuous distributed temperature profile points to a thermal gradient of about 200 °C km-1. Our findings (i) indicate that scale-dependency of permeability has to be carefully considered in modelling of the hydrothermal system at Campi Flegrei, and (ii) improve the understanding of caldera dynamics for monitoring and mitigation of this very high volcanic risk area.

Modeling of Permeability Structure Using Pore Pressure and Borehole Strain Monitoring

NASA Astrophysics Data System (ADS)

Kano, Y.; Ito, H.

2011-12-01

Hydraulic or transport property, especially permeability, of the rock affect the behavior of the fault during earthquake rupture and also interseismic period. The methods to determine permeability underground are hydraulic test utilizing borehole and packer or core measurement in laboratory. Another way to know the permeability around a borehole is to examine responses of pore pressure to natural loading such as barometric pressure change at surface or earth tides. Using response to natural deformation is conventional method for water resource research. The scale of measurement is different among in-situ hydraulic test, response method, and core measurement. It is not clear that the relationship between permeability values form each method for an inhomogeneous medium such as a fault zone. Supposing the measurement of the response to natural loading, we made a model calculation of permeability structure around a fault zone. The model is 2 dimensional and constructed with vertical high-permeability layer in uniform low-permeability zone. We assume the upper and lower boundaries are drained and no-flow condition. We calculated the flow and deformation of the model for step and cyclic loading by numerically solving a two-dimensional diffusion equation. The model calculation shows that the width of the high-permeability zone and contrast of the permeability between high- and low- permeability zones control the contribution of the low-permeability zone. We made a calculation with combinations of permeability and fault width to evaluate the sensitivity of the parameters to in-situ measurement of permeability. We applied the model calculation to the field results of in-situ packer test, and natural response of water level and strain monitoring carried out in the Kamioka mine. The model calculation shows that knowledge of permeability in host rock is also important to obtain permeability of fault zone itself. The model calculations help to design long-term pore pressure

Experimental Studies on Permeability of Intact and Singly Jointed Meta-Sedimentary Rocks Under Confining Pressure

NASA Astrophysics Data System (ADS)

Wong, Louis Ngai Yuen; Li, Diyuan; Liu, Gang

2013-01-01

spanning from 1.25 to 5.0 MPa, which represent the typical ground stress conditions in the cavern. The in situ hydraulic conductivity measurements conducted in six boreholes by the injection test showed that the in situ permeability of rock mass varies between 10-18 and 10-11 m2. The lower bound of the in situ permeability is larger than that of the present laboratory-tested intact rock specimens, while the upper bound of the in situ permeability is less than that of the present laboratory-tested jointed rock specimens. The in situ permeability test results were thus compatible with our present laboratory permeability results of both intact and jointed rock specimens.

Water permeability is a measure of severity in acute appendicitis.

PubMed

Pini, Nicola; Pfeifle, Viktoria A; Kym, Urs; Keck, Simone; Galati, Virginie; Holland-Cunz, Stefan; Gros, Stephanie J

2017-12-01

Acute appendicitis is the most common indication for pediatric abdominal emergency surgery. Determination of the severity of appendicitis on clinical grounds is challenging. Complicated appendicitis presenting with perforation, abscess or diffuse peritonitis is not uncommon. The question remains why and when acute appendicitis progresses to perforation. The aim of this study was to assess the impact of water permeability on the severity of appendicitis. We show that AQP1 expression and water permeability in appendicitis correlate with the stage of inflammation and systemic infection parameters, leading eventually to perforation of the appendix. AQP1 is also expressed within the ganglia of the enteric nervous system and ganglia count increases with inflammation. Severity of appendicitis can be correlated with water permeability measured by AQP1 protein expression and increase of ganglia count in a progressive manner. This introduces the question if regulation of water permeability can present novel curative or ameliorating therapeutic options.

Device and method for the measurement of gas permeability through membranes

DOEpatents

Agarwal, Pradeep K.; Ackerman, John; Borgialli, Ron; Hamann, Jerry; Muknahalliptna, Suresh

2006-08-08

A device for the measuring membrane permeability in electrical/electrochemical/photo-electrochemical fields is provided. The device is a permeation cell and a tube mounted within the cell. An electrode is mounted at one end of the tube. A membrane is mounted within the cell wherein a corona is discharged from the electrode in a general direction toward the membrane thereby generating heated hydrogen atoms adjacent the membrane. A method for measuring the effects of temperature and pressure on membrane permeability and selectivity is also provided.

Micromechanical Modeling of Anisotropic Damage-Induced Permeability Variation in Crystalline Rocks

NASA Astrophysics Data System (ADS)

Chen, Yifeng; Hu, Shaohua; Zhou, Chuangbing; Jing, Lanru

2014-09-01

This paper presents a study on the initiation and progress of anisotropic damage and its impact on the permeability variation of crystalline rocks of low porosity. This work was based on an existing micromechanical model considering the frictional sliding and dilatancy behaviors of microcracks and the recovery of degraded stiffness when the microcracks are closed. By virtue of an analytical ellipsoidal inclusion solution, lower bound estimates were formulated through a rigorous homogenization procedure for the damage-induced effective permeability of the microcracks-matrix system, and their predictive limitations were discussed with superconducting penny-shaped microcracks, in which the greatest lower bounds were obtained for each homogenization scheme. On this basis, an empirical upper bound estimation model was suggested to account for the influences of anisotropic damage growth, connectivity, frictional sliding, dilatancy, and normal stiffness recovery of closed microcracks, as well as tensile stress-induced microcrack opening on the permeability variation, with a small number of material parameters. The developed model was calibrated and validated by a series of existing laboratory triaxial compression tests with permeability measurements on crystalline rocks, and applied for characterizing the excavation-induced damage zone and permeability variation in the surrounding granitic rock of the TSX tunnel at the Atomic Energy of Canada Limited's (AECL) Underground Research Laboratory (URL) in Canada, with an acceptable agreement between the predicted and measured data.

Development of Helium-Mass-Spectrometry-Permeameter for the Measurement of Permeability of Near-Impermeable Rock

NASA Astrophysics Data System (ADS)

Lee, Moo Y.; Bauer, Stephen J.

2016-12-01

A helium leakage detection system was modified to measure gas permeability on extracted cores of nearly impermeable rock. The Helium-Mass-Spectrometry-Permeameter (HMSP) is duplicating the classic Darcy's experiment with a constant pressure differential and steady-state flow through a sample using helium gas. Under triaxial stress condition, the newly developed HMSP can measure hydraulic permeability of rocks and geomaterials down to the nanoDarcy scale (10-21 m2). The extension of measuring the lower end of the permeability scale may help answer important questions regarding the permeability of rock at great depth where fractures may close completely under high lithostatic stress.

Permeability enhancement by shock cooling

NASA Astrophysics Data System (ADS)

Griffiths, Luke; Heap, Michael; Reuschlé, Thierry; Baud, Patrick; Schmittbuhl, Jean

2015-04-01

The permeability of an efficient reservoir, e.g. a geothermal reservoir, should be sufficient to permit the circulation of fluids. Generally speaking, permeability decreases over the life cycle of the geothermal system. As a result, is usually necessary to artificially maintain and enhance the natural permeability of these systems. One of the methods of enhancement -- studied here -- is thermal stimulation (injecting cold water at low pressure). This goal of this method is to encourage new thermal cracks within the reservoir host rocks, thereby increasing reservoir permeability. To investigate the development of thermal microcracking in the laboratory we selected two granites: a fine-grained (Garibaldi Grey granite, grain size = 0.5 mm) and a course-grained granite (Lanhelin granite, grain size = 2 mm). Both granites have an initial porosity of about 1%. Our samples were heated to a range of temperatures (100-1000 °C) and were either cooled slowly (1 °C/min) or shock cooled (100 °C/s). A systematic microstructural (2D crack area density, using standard stereological techniques, and 3D BET specific surface area measurements) and rock physical property (porosity, P-wave velocity, uniaxial compressive strength, and permeability) analysis was undertaken to understand the influence of slow and shock cooling on our reservoir granites. Microstructurally, we observe that the 2D crack surface area per unit volume and the specific surface area increase as a result of thermal stressing, and, for the same maximum temperature, crack surface area is higher in the shock cooled samples. This observation is echoed by our rock physical property measurements: we see greater changes for the shock cooled samples. We can conclude that shock cooling is an extremely efficient method of generating thermal microcracks and modifying rock physical properties. Our study highlights that thermal treatments are likely to be an efficient method for the "matrix" permeability enhancement of

Real-time Measurement of Epithelial Barrier Permeability in Human Intestinal Organoids.

PubMed

Hill, David R; Huang, Sha; Tsai, Yu-Hwai; Spence, Jason R; Young, Vincent B

2017-12-18

Advances in 3D culture of intestinal tissues obtained through biopsy or generated from pluripotent stem cells via directed differentiation, have resulted in sophisticated in vitro models of the intestinal mucosa. Leveraging these emerging model systems will require adaptation of tools and techniques developed for 2D culture systems and animals. Here, we describe a technique for measuring epithelial barrier permeability in human intestinal organoids in real-time. This is accomplished by microinjection of fluorescently-labeled dextran and imaging on an inverted microscope fitted with epifluorescent filters. Real-time measurement of the barrier permeability in intestinal organoids facilitates the generation of high-resolution temporal data in human intestinal epithelial tissue, although this technique can also be applied to fixed timepoint imaging approaches. This protocol is readily adaptable for the measurement of epithelial barrier permeability following exposure to pharmacologic agents, bacterial products or toxins, or live microorganisms. With minor modifications, this protocol can also serve as a general primer on microinjection of intestinal organoids and users may choose to supplement this protocol with additional or alternative downstream applications following microinjection.

Characterisation and monitoring of the Excavation Disturbed Zone (EDZ) in fractured gneisses of the Roselend underground laboratory: permeability measurements, transport property changes and related radon bursts

NASA Astrophysics Data System (ADS)

Wassermann, Jérôme; Sabroux, Jean-Christophe; Richon, Patrick; Pontreau, Sébastien; Guillon, Sophie; Pili, Eric

2010-05-01

The Roselend tunnel was drilled in the fifties by blasting in the micashists, granites and gneisses of the Méraillet massif (French Alps). It is situated on the shore of the Roselend reservoir Lake near its dam. Several tectonic shear fractures related to the Alpine orogeny intersect the dead end tunnel (with length of 128 m and section about 2 m), indeed the fracture density varies from 0.45 to 1 fracture per meter along the tunnel (Dezayes and Villemin 2002). Some fractures are partially or totally filled with secondary minerals. The flow rates of percolating water through the fractured medium are seasonal dependent. Large fractures drain a large fluid volume unlike small ones that drain limited fluid volume (Patriarche et al. 2007). The Roselend underground laboratory allows the study of the geochemical and geophysical responses of a fractured rock mass to periodic sollicitations due to water level variations of the nearby Roselend reservoir Lake. The tunnel was instrumented in the nineties to understand the relationship between radon (Rn-222) concentration and water level variations of the Roselend reservoir Lake (Trique et al. 1999). In order to characterize the geometry and the extent of the EDZ, core drilling and permeability measurements through pneumatic testing are performed along the Roselend tunnel. Drilled core analysis consists of direct observations at a macroscopic scale of fractures (density of fractures from EDZ) and also at a microscopic scale via thin sections. Method of pressure build-up in wells (Jakubick and Franz 1993, Bossart et al. 2002) is used to determine permeability profile along each borehole and hence to precise the extent and geometry of the EDZ. A strong correlation is observed between permeability profiles and the density of fractures estimated from core analysis. The extent of the EDZ appears to be about one tunnel radius i.e. one meter around the tunnel corridor. Another experiment consisting of continuous differential

Permeability measurements on rock samples from Unzen Scientific Drilling Project Drill Hole 4 (USDP-4)

NASA Astrophysics Data System (ADS)

Watanabe, Tohru; Shimizu, Yuhta; Noguchi, Satoshi; Nakada, Setsuya

2008-07-01

Permeability measurement was made on five rock samples from USDP-4 cores. Rock samples were collected from the conduit zone and its country rock. One sample (C14-1-1) is considered as a part of the feeder dyke for the 1991-1995 eruption. The transient pulse method was employed under confining pressure up to 50 MPa. Compressional wave velocity was measured along with permeability. The measured permeability ranges from 10 - 19 to 10 - 17 m 2 at the atmospheric pressure, and is as low as that reported for tight rocks such as granite. The permeability decreases with increasing confining pressure, while the compressional wave velocity increases. Assuming that pores are parallel elliptical tubes, the pressure dependence of permeability requires aspect ratio of 10 - 4 -10 - 2 at the atmospheric pressure. The pore aperture is estimated to be less than 1 μm. The estimated aspect ratio and pore aperture suggest that connectivity of pores is maintained by narrow cracks. The existence of cracks is supported by the pressure dependence of compressional wave velocity. Narrow cracks (< 1 μm) are observed in dyke samples, and they must have been created after solidification. Dyke samples do not provide us information of pore structures during degassing, since exsolved gas has mostly escaped and pores governing the gas permeable flow should have been lost. Both dyke and country rock samples provide us information of materials around ascending magma. Although the measured small-scale permeability cannot be directly applied to geological-scale processes, it gives constrains on studies of large-scale permeability.

Scale dependence of in-situ permeability measurements in the Nankai accretionary prism: The role of fractures

NASA Astrophysics Data System (ADS)

Boutt, David F.; Saffer, Demian; Doan, Mai-Linh; Lin, Weiren; Ito, Takatoshi; Kano, Yasuyuki; Flemings, Peter; McNeill, Lisa C.; Byrne, Timothy; Hayman, Nicholas W.; Moe, Kyaw Thu

2012-04-01

Modeling studies suggest that fluid permeability is an important control on the maintenance and distribution of pore fluid pressures at subduction zones generated through tectonic loading. Yet, to date, few data are available to constrain permeability of these materials, at appropriate scales. During IODP Expedition 319, downhole measurements of permeability within the uppermost accretionary wedge offshore SW Japan were made using a dual-packer device to isolate 1 m sections of borehole at a depth of 1500 m below sea floor. Analyses of pressure transients using numerical models suggest a range of in-situ fluid permeabilities (5E-15-9E-17 m2). These values are significantly higher than those measured on core samples (2E-19 m2). Borehole imagery and cores suggests the presence of multiple open fractures at this depth of measurement. These observations suggest that open permeable natural fractures at modest fracture densities could be important contributors to overall prism permeability structure at these scales.

Permeability of stylolite-bearing chalk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lind, I.; Nykjaer, O.; Priisholm, S.

1994-11-01

Permeabilities were measured on core plugs from stylolite-bearing chalk of the Gorm field in the Danish North Sea. Air and liquid permeabilities were measured in directions parallel to and perpendicular to the stylolite surface. Permeability was measured with sleeve pressure equal to in-situ reservoir stress. Permeabilities of plugs with stylolites but without stylolite-associated fractures were equal in the two directions. The permeability is equal to the matrix permeability of non-stylolite-bearing chalk. In contrast, when fractures were associated with the stylolites, permeability was enhanced. The enhancement was most significant in the horizontal direction parallel to the stylolites.

Characterization of fracture permeability with high-resolution vertical flow measurements during borehole pumping.

USGS Publications Warehouse

Paillet, Frederick L.; Hess, A.E.; Cheng, C.H.; Hardin, E.

1987-01-01

The distribution of fracture permeability in granitic rocks was investigated by measuring the distribution of vertical flow in boreholes during periods of steady pumping. Pumping tests were conducted at two sites chosen to provide examples of moderately fractured rocks near Mirror Lake, New Hampshire and intensely fractured rocks near Oracle, Arizona. A sensitive heat-pulse flowmeter was used for accurate measurements of vertical flow as low as 0.2 liter per minute. Results indicate zones of fracture permeability in crystalline rocks are composed of irregular conduits that cannot be approximated by planar fractures of uniform aperture, and that the orientation of permeability zones may be unrelated to the orientation of individual fractures within those zones.-Authors

Measurement and evaluation of the relationships between capillary pressure, relative permeability, and saturation for surrogate fluids for laboratory study of geological carbon sequestration

NASA Astrophysics Data System (ADS)

Mori, H.; Trevisan, L.; Sakaki, T.; Cihan, A.; Smits, K. M.; Illangasekare, T. H.

2013-12-01

Multiphase flow models can be used to improve our understanding of the complex behavior of supercritical CO2 (scCO2) in deep saline aquifers to make predictions for the stable storage strategies. These models rely on constitutive relationships such as capillary pressure (Pc) - saturation (Sw) and relative permeability (kr) - saturation (Sw) as input parameters. However, for practical application of these models, such relationships for scCO2 and brine system are not readily available for geological formations. This is due to the complicated and expensive traditional methods often used to obtain these relationships in the laboratory through high pressure and/or high-temperature controls. A method that has the potential to overcome the difficulty in conducting such experiments is to replicate scCO2 and brine with surrogate fluids that capture the density and viscosity effects to obtain the constitutive relationships under ambient conditions. This study presents an investigation conducted to evaluate this method. An assessment of the method allows us to evaluate the prediction accuracy of multiphase models using the constitutive relationships developed from this approach. With this as a goal, the study reports multiple laboratory column experiments conducted to measure these relationships. The obtained relationships were then used in the multiphase flow simulator TOUGH2 T2VOC to explore capillary trapping mechanisms of scCO2. A comparison of the model simulation to experimental observation was used to assess the accuracy of the measured constitutive relationships. Experimental data confirmed, as expected, that the scaling method cannot be used to obtain the residual and irreducible saturations. The results also showed that the van Genuchten - Mualem model was not able to match the independently measured kr data obtained from column experiments. Simulated results of fluid saturations were compared with saturation measurements obtained using x-ray attenuations. This

Unsaturated hydraulic behaviour of a permeable pavement: Laboratory investigation and numerical analysis by using the HYDRUS-2D model

NASA Astrophysics Data System (ADS)

Turco, Michele; Kodešová, Radka; Brunetti, Giuseppe; Nikodem, Antonín; Fér, Miroslav; Piro, Patrizia

2017-11-01

An adequate hydrological description of water flow in permeable pavement systems relies heavily on the knowledge of the unsaturated hydraulic properties of the construction materials. Although several modeling tools and many laboratory methods already exist in the literature to determine the hydraulic properties of soils, the importance of an accurate materials hydraulic description of the permeable pavement system, is increasingly recognized in the fields of urban hydrology. Thus, the aim of this study is to propose techniques/procedures on how to interpret water flow through the construction system using the HYDRUS model. The overall analysis includes experimental and mathematical procedures for model calibration and validation to assess the suitability of the HYDRUS-2D model to interpret the hydraulic behaviour of a lab-scale permeable pavement system. The system consists of three porous materials: a wear layer of porous concrete blocks, a bedding layers of fine gravel, and a sub-base layer of coarse gravel. The water regime in this system, i.e. outflow at the bottom and water contents in the middle of the bedding layer, was monitored during ten irrigation events of various durations and intensities. The hydraulic properties of porous concrete blocks and fine gravel described by the van Genuchten functions were measured using the clay tank and the multistep outflow experiments, respectively. Coarse gravel properties were set at literature values. In addition, some of the parameters (Ks of the concrete blocks layer, and α, n and Ks of the bedding layer) were optimized with the HYDRUS-2D model from water fluxes and soil water contents measured during irrigation events. The measured and modeled hydrographs were compared using the Nash-Sutcliffe efficiency (NSE) index (varied between 0.95 and 0.99) while the coefficient of determination R2 was used to assess the measured water content versus the modelled water content in the bedding layer (R2 = 0.81 ÷ 0.87) . The

Permeability of human jejunal segments to gonyautoxins measured by the Ussing chamber technique.

PubMed

Mardones, Pamela; Andrinolo, Darío; Csendes, Attila; Lagos, Néstor

2004-10-01

The aim of this work was to study the mechanisms involved in intestinal permeability of gonyautoxins. For this purpose, the influence on transmucosal resistance of gonyautoxins and their permeability was investigated in excised human jejunal segments. To evaluate these events, the isolated mucosa was mounted in Ussing chambers for electrophysiological characterization. The organic gonyautoxin cations were applied to the mucosal side and samples collected on the serosal side. The permeability of gonyautoxins measured at 37 degrees C was 4.3-fold greater than at 4 degrees C, indicative of high cation selective transcellular permeability. In order to characterize the permeability of gonyautoxins, the effects of choline, ouabain, phlorizin and fluorescein were studied. The inhibition by these compounds was expressed as percent inhibition of the maximal flux of gonyautoxins at 120 min. Replacement of sodium ion by choline, showed the highest inhibition (85.5% from control). Ouabain, fluorescein and phlorizin inhibit the gonyautoxins flux by 53.9, 41.0 and 9.64%, respectively. The inhibition of gonyautoxins' permeability produced by ouabain and phlorizin go in parallel with an increase in the transmucosal electrical resistance (TER). This study shows that permeability of gonyautoxin cations occurred predominantly by the transcellular pathway (76%) when toxins were applied in the mucosal-serosal direction. The paracellular pathway of gonyautoxins was 24% of total permeability when compared with [3H] mannitol permeability. These findings suggests that permeability of gonyautoxins depends on temperature and processes involving sodium ion. Replacing sodium ions by choline ions showed a marked effect on TER.

A survey of methods for the evaluation of tissue engineering scaffold permeability.

PubMed

Pennella, F; Cerino, G; Massai, D; Gallo, D; Falvo D'Urso Labate, G; Schiavi, A; Deriu, M A; Audenino, A; Morbiducci, Umberto

2013-10-01

The performance of porous scaffolds for tissue engineering (TE) applications is evaluated, in general, in terms of porosity, pore size and distribution, and pore tortuosity. These descriptors are often confounding when they are applied to characterize transport phenomena within porous scaffolds. On the contrary, permeability is a more effective parameter in (1) estimating mass and species transport through the scaffold and (2) describing its topological features, thus allowing a better evaluation of the overall scaffold performance. However, the evaluation of TE scaffold permeability suffers of a lack of uniformity and standards in measurement and testing procedures which makes the comparison of results obtained in different laboratories unfeasible. In this review paper we summarize the most important features influencing TE scaffold permeability, linking them to the theoretical background. An overview of methods applied for TE scaffold permeability evaluation is given, presenting experimental test benches and computational methods applied (1) to integrate experimental measurements and (2) to support the TE scaffold design process. Both experimental and computational limitations in the permeability evaluation process are also discussed.

Permeability Development at Layer Interfaces in Bedded Rocksalt

NASA Astrophysics Data System (ADS)

Muhammad, N.; Spiers, C. J.; Peach, C. J.; De Bresser, J. H. P.; Liu, W.

2016-12-01

Solution mined salt caverns are of great interest for storage of fluids such as compressed air, natural gas or hydrogen fuel, and are expected to show excellent healing and sealing capacity. However, it is of utmost importance to be able to reliably quantify the permeability of salt cavern walls, so that potential loss of the stored asset may be assessed. Data on dilatancy, permeability and damage development are readily available for pure rocksalt undergoing deformation, but little is known about the permeability development at the bedding interfaces within layered salt under varying differential stresses. Layered salt samples were obtained from the walls of a pilot well in Hubei province China. The natural salt shows alternating layers of rock salt, anhydrite, mudstone and glauberite. Cylindrical samples, 50 mm diameter and 85 mm long, were prepared with layer interfaces oriented vertical, horizontal or obliquely to the core axis. Tests were conducted at room temperature and a confining pressure of 20 and (for shallower depth) 10 MPa, representing in-situ conditions. Axial deformation was performed using a triaxial machine in the HPT-laboratory at Utrecht. Compaction/dilation was measured using a servo control dilatometer for confining pressure control, and, in conjunction, the permeability was measured using Argon gas transient step permeameter. The samples were deformed at a constant displacement rate of 1 µm/s. After reaching 10, 20 and 30 MPa differential stress, deformation was halted and permeability was measured parallel to the compositional interfaces for each of the three geometries. Overall, it was found that during deformation, no shear slippage occurred at interface and the bulk permeability of most specimens decreased, where the absolute permeability value (found in the range 10-15 to <10-21 m2) depending upon the orientation of the bedding interface and composition of the sample. All samples showed a decrease in volume with axial strain

Laboratory test investigations on soil water characteristic curve and air permeability of municipal solid waste.

PubMed

Shi, Jianyong; Wu, Xun; Ai, Yingbo; Zhang, Zhen

2018-05-01

The air permeability coefficient has a high correlation with the water content of municipal solid waste. In this study, continuous drying methodology using a tension meter was employed to construct the soil water characteristic curve of municipal solid waste (M-SWCC). The municipal solid waste air permeability test was conducted by a newly designed apparatus. The measured M-SWCC was well reproduced by the van Genuchten (V-G) model and was used to predict the parameters of typical points in M-SWCC, including saturated water content, field capacity, residual water content and water content at the inflection point. It was found that the M-SWCC was significantly influenced by void ratio. The final evaporation and test period of M-SWCC increase with the increase in void ratio of municipal solid waste. The evolution of air permeability coefficient with water content of municipal solid waste depicted three distinct characteristic stages. It was observed that the water contents that corresponded to the two cut-off points of the three stages were residual water content and water content at the inflection point, respectively. The air permeability coefficient of municipal solid waste decreased with the increase of the water content from zero to the residual water content. The air permeability coefficient was almost invariable when the water content increased from residual water content to the water content at the inflection point. When the water content of municipal solid waste exceeded the water content at the inflection point, the air permeability coefficient sharply decreased with the increase of water content.

Gas permeability measurements for film envelope materials

DOEpatents

Ludtka, Gerard M.; Kollie, Thomas G.; Watkin, David C.; Walton, David G.

1998-01-01

Method and apparatus for measuring the permeability of polymer film materials such as used in super-insulation powder-filled evacuated panels (PEPs) reduce the time required for testing from several years to weeks or months. The method involves substitution of a solid non-outgassing body having a free volume of between 0% and 25% of its total volume for the usual powder in the PEP to control the free volume of the "body-filled panel". Pressure versus time data for the test piece permit extrapolation to obtain long term performance of the candidate materials.

Axial and Radial Permeability Evolutions of Compressed Sandstones: End Effects and Shear-band Induced Permeability Anisotropy

NASA Astrophysics Data System (ADS)

Dautriat, Jeremie; Gland, Nicolas; Guelard, Jean; Dimanov, Alexandre; Raphanel, Jean L.

2009-07-01

The influence of hydrostatic and uniaxial stress states on the porosity and permeability of sandstones has been investigated. The experimental procedure uses a special triaxial cell which allows permeability measurements in the axial and radial directions. The core sleeve is equipped with two pressure samplers placed distant from the ends. They provide mid-length axial permeability measure as opposed to the overall permeability measure, which is based on the flow imposed through the pistons of the triaxial cell. The core sleeve is also equipped to perform flows in two directions transverse to the axis of the sample. Two independent measures of axial and complementary radial permeability are thus obtained. Both Fontainebleau sandstone specimens with a porosity of about 5.8% to 8% and low permeability ranging from 2.5 mD to 30 mD and Bentheimer sandstone with a porosity of 24% and a high permeability of 3 D have been tested. The initial axial permeability values obtained by each method are in good agreement for the Fontainebleau sandstone. The Bentheimer sandstone samples present an axial mid-length permeability 1.6 times higher than the overall permeability. A similar discrepancy is also observed in the radial direction, also it relates essentially to the shape of flow lines induced by the radial flow. All the tested samples have shown a higher stress dependency of overall and radial permeability than mid-length permeability. The effect of compaction damage at the pistons/sample and radial ports/sample interfaces is discussed. The relevance of directional permeability measurements during continuous uniaxial compression loadings has been shown on the Bentheimer sandstone until the failure of the sample. We can efficiently measure the influence of brittle failure associated to dilatant regime on the permeability: It tends to increase in the failure propagation direction and to decrease strongly in the transverse direction.

Analysis of field permeability and laboratory shear stress for Western Kentucky Parkway, milepost 18.240 to milepost 25.565, Caldwell-Hopkins counties

DOT National Transportation Integrated Search

2003-02-01

This report lists and discusses results of field permeability tests and laboratory shear tests on samples from a construction project on the Western Kentucky Parkway in Caldwell-Hopkins Counties. Approximately 6,500 tons of asphaltic concrete overlay...

Permeability Evolution of Propped Artificial Fractures in Green River Shale

NASA Astrophysics Data System (ADS)

Li, Xiang; Feng, Zijun; Han, Gang; Elsworth, Derek; Marone, Chris; Saffer, Demian; Cheon, Dae-Sung

2017-06-01

This paper compares the evolution of permeability with effective stress in propped fractures in shale for native CH4 compared with that for sorbing CO2, slightly sorbing N2 and non-sorbing He. We examine the response for laboratory experiments on artificial propped fractures in Green River Shale to explore mechanisms of proppant embedment and fracture diagenesis. Split cylindrical specimens sandwich a proppant bead-pack at a constant confining stress of 20 MPa and with varied pore pressure. Permeability and sorption characteristics are measured with the pulse transient method. To explore the effect of swelling and embedment on fracture surface geometry, we measure the evolution of conductivity characteristics for different proppant geometries (single layer vs. multilayer), gas saturation and specimen variation in order to simulate both production and enhanced gas recovery. The resulting morphology of embedment is measured by white light interferometry and characterized via surface roughness parameter of mean, maximum and root-mean-square amplitudes. For both strongly (CO2, CH4) and slightly adsorptive gases (N2), the permeability first decreases with an increase in gas pressure due to swelling before effective stress effects dominate above the Langmuir pressure threshold. CO2 with its highest adsorption affinity produces the lowest permeability among these three gas permeants. Monolayer propped specimens show maximum swelling and lowered k/k 0 ratio and increased embedment recorded in the surface roughness relative to the multilayered specimens. Permeabilities measured for both injection and depletion cycles generally overlap and are repeatable with little hysteresis. This suggests the dominant role of reversible swelling over irreversible embedment. Gas permeant composition and related swelling have an important effect on the permeability evolution of shales.

Inclusion of Topological Measurements into Analytic Estimates of Effective Permeability in Fractured Media

NASA Astrophysics Data System (ADS)

Sævik, P. N.; Nixon, C. W.

2017-11-01

We demonstrate how topology-based measures of connectivity can be used to improve analytical estimates of effective permeability in 2-D fracture networks, which is one of the key parameters necessary for fluid flow simulations at the reservoir scale. Existing methods in this field usually compute fracture connectivity using the average fracture length. This approach is valid for ideally shaped, randomly distributed fractures, but is not immediately applicable to natural fracture networks. In particular, natural networks tend to be more connected than randomly positioned fractures of comparable lengths, since natural fractures often terminate in each other. The proposed topological connectivity measure is based on the number of intersections and fracture terminations per sampling area, which for statistically stationary networks can be obtained directly from limited outcrop exposures. To evaluate the method, numerical permeability upscaling was performed on a large number of synthetic and natural fracture networks, with varying topology and geometry. The proposed method was seen to provide much more reliable permeability estimates than the length-based approach, across a wide range of fracture patterns. We summarize our results in a single, explicit formula for the effective permeability.

Effective pressure law for permeability of E-bei sandstones

NASA Astrophysics Data System (ADS)

Li, M.; Bernabé, Y.; Xiao, W.-I.; Chen, Z.-Y.; Liu, Z.-Q.

2009-07-01

Laboratory experiments were conducted to determine the effective pressure law for permeability of tight sandstone rocks from the E-bei gas reservoir, China. The permeability k of five core samples was measured while cycling the confining pressure pc and fluid pressure pf. The permeability data were analyzed using the response-surface method, a statistical model-building approach yielding a representation of k in (pc, pf) space that can be used to determine the effective pressure law, i.e., peff = pc - κpf. The results show that the coefficient κ of the effective pressure law for permeability varies with confining pressure and fluid pressure as well as with the loading or unloading cycles (i.e., hysteresis effect). Moreover, κ took very small values in some of the samples, even possibly lower than the value of porosity, in contradiction with a well-accepted theoretical model. We also reanalyzed a previously published permeability data set on fissured crystalline rocks and found again that the κ varies with pc but did not observe κ values lower than 0.4, a value much larger than porosity. Analysis of the dependence of permeability on effective pressure suggests that the occurrence of low κ values may be linked to the high-pressure sensitivity of E-bei sandstones.

Permeability-porosity data sets for sandstones

USGS Publications Warehouse

Nelson, P.H.

2004-01-01

Due to the variable nature of permeability-porosity relations, core should be obtained and permeability (k) and porosity (??) should be determined on core plugs in the laboratory for the formation of interest. A catalog of k versus (??) data sets is now available on the Web. Examples from the catalog are considered to illustrate some aspects of k versus ?? dependencies in siliciclastic reservoirs.

In Situ Measurement of Permeability in the Vicinity of Faulted Nonwelded Bishop Tuff, Bishop, CA

NASA Astrophysics Data System (ADS)

Dinwiddie, C. L.; Fedors, R. W.; Ferrill, D. A.; Bradbury, K. K.

2002-12-01

The nonwelded Bishop Tuff includes matrix-supported massive ignimbrites and clast-supported bedded deposits. Fluid flow through such faulted nonwelded tuff is likely to be influenced by a combination of host rock properties and the presence of deformation features, such as open fractures, mineralized fractures, and fault zones that exhibit comminuted fault rock and clays. Lithologic contacts between fine- and coarse-grained sub-units of nonwelded tuff may induce formation of capillary and/or permeability barriers within the unsaturated zone, potentially leading to down-dip lateral diversion of otherwise vertically flowing fluid. However, discontinuities (e.g., fractures and faults) may lead to preferential sub-vertical fast flow paths in the event of episodic infiltration rates, thus disrupting the potential for both (1) large-scale capillary and/or permeability barriers to form and for (2) redirection of water flow over great lateral distances. This study focuses on an innovative technique for measuring changes in matrix permeability near faults in situ--changes that may lead to enhancement of vertical fluid flow and disruption of lateral fluid flow. A small-drillhole minipermeameter probe provides a means to eliminate extraction of fragile nonwelded tuffs as a necessity for permeability measurement. Advantages of this approach include (1) a reduction of weathering-effects on measured permeability, and (2) provision of a superior sealing mechanism around the gas injection zone. In order to evaluate the effect of faults and fault zone deformation on nonwelded tuff matrix permeability, as well as to address the potential for disruption of lithologic barrier-induced lateral diversion of flow, data were collected from two fault systems and from unfaulted host rock. Two hundred and sixty-seven gas-permeability measurements were made at 89 locations; i.e. permeability measurements were made in triplicate at each location with three flow rates. Data were collected at the

Gas permeability measurements for film envelope materials

DOEpatents

Ludtka, G.M.; Kollie, T.G.; Watkin, D.C.; Walton, D.G.

1998-05-12

Method and apparatus for measuring the permeability of polymer film materials such as used in super-insulation powder-filled evacuated panels (PEPs) reduce the time required for testing from several years to weeks or months. The method involves substitution of a solid non-outgassing body having a free volume of between 0% and 25% of its total volume for the usual powder in the PEP to control the free volume of the ``body-filled panel.`` Pressure versus time data for the test piece permit extrapolation to obtain long term performance of the candidate materials. 4 figs.

Fluid permeability measurement system and method

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John [Oak Ridge, TN

2008-02-05

A system for measuring the permeance of a material. The permeability of the material may also be derived. The system provides a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Microwave techniques for measuring complex permittivity and permeability of materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillon, P.

1995-08-01

Different materials are of fundamental importance to the aerospace, microwave, electronics and communications industries, and include for example microwave absorbing materials, antennas lenses and radomes, substrates for MMIC and microwave components and antennaes. Basic measurements for the complex permittivity and permeability of those homogeneous solid materials in the microwave spectral region are described including hardware, instrumentation and analysis. Elevated temperature measurements as well as measurements intercomparisons, with a discussion of the strengths and weaknesses of each techniques are also presented.

3-D Printing as a Tool to Investigate the Effects of Changes in Rock Microstructures on Permeability

NASA Astrophysics Data System (ADS)

Head, D. A.; Vanorio, T.

2016-12-01

Rocks are naturally heterogeneous; two rock samples with identical bulk properties can vary widely in microstructure. Understanding the evolutionary trends of rock properties requires the ability to connect time-lapse measurements of properties at different scales: the macro- scale used in the laboratory and field analyses capturing the bulk scale changes and the micro- scale used in imaging and digital techniques capturing the changes to the pore space. However, measuring those properties at different scales is very challenging, and sometimes impossible. The advent of modern 3D printing has provided an unprecedented opportunity to link those scales by combining the strengths of digital and experimental rock physics. To determine the feasibility of this technique we characterized the resolution capabilities of two different 3D printers. To calibrate our digital models with our printed models, we created a sample with an analytically solvable permeability. This allowed us to directly compare analytic calculation, numerical simulation, and laboratory measurement of permeability of the exact same sample. Next we took a CT-scanned model of a natural carbonate pore space, then iteratively digitally manipulated, 3D printed, and measured the flow properties in the laboratory. This approach allowed us to access multiple scales digitally and experimentally, to test hypotheses about how changes in rock microstructure due to compaction and dissolution affect bulk transport properties, and to connect laboratory measurements of porosity and permeability to quantities that are traditionally impossible to measure in the laboratory such as changes in surface area and tortuosity. As 3D printing technology continues to advance, we expect this technique to contribute to our ability to characterize the properties of remote and/or delicate samples as well as to test the impact of microstructural alteration on bulk physical properties in the lab in a highly consistent, repeatable manner.

USE OF SEMI-PERMEABLE MEMBRANE DEVICES TO MONITOR POLLUTANTS IN WATER AND ASSESS THEIR EFFECTS: A LABORATORY TEST AND FIELD VERIFICATION. (U915464)

EPA Science Inventory

Uptake of eight pesticides of different classes (organochlorines, synthetic pyrethroids, dinitroanilines, amides) by semi-permeable membrane devices (SPMDs) was studied in a laboratory continuous-flow system. After 20 days of exposure, membrane concentration factors were in th...

Fracture characterization and fracture-permeability estimation at the underground research laboratory in southeastern Manitoba, Canada

USGS Publications Warehouse

Paillet, Frederick L.

1988-01-01

Various conventional geophysical well logs were obtained in conjunction with acoustic tube-wave amplitude and experimental heat-pulse flowmeter measurements in two deep boreholes in granitic rocks on the Canadian shield in southeastern Manitoba. The objective of this study is the development of measurement techniques and data processing methods for characterization of rock volumes that might be suitable for hosting a nuclear waste repository. One borehole, WRA1, intersected several major fracture zones, and was suitable for testing quantitative permeability estimation methods. The other borehole, URL13, appeared to intersect almost no permeable fractures; it was suitable for testing methods for the characterization of rocks of very small permeability and uniform thermo-mechanical properties in a potential repository horizon. Epithermal neutron , acoustic transit time, and single-point resistance logs provided useful, qualitative indications of fractures in the extensively fractured borehole, WRA1. A single-point log indicates both weathering and the degree of opening of a fracture-borehole intersection. All logs indicate the large intervals of mechanically and geochemically uniform, unfractured granite below depths of 300 m in the relatively unfractured borehole, URL13. Some indications of minor fracturing were identified in that borehole, with one possible fracture at a depth of about 914 m, producing a major acoustic waveform anomaly. Comparison of acoustic tube-wave attenuation with models of tube-wave attenuation in infinite fractures of given aperture provide permeability estimates ranging from equivalent single-fractured apertures of less than 0.01 mm to apertures of > 0.5 mm. One possible fracture anomaly in borehole URL13 at a depth of about 914 m corresponds with a thin mafic dike on the core where unusually large acoustic contrast may have produced the observed waveform anomaly. No indications of naturally occurring flow existed in borehole URL13; however

An improved method for permeability estimation of the bioclastic limestone reservoir based on NMR data

NASA Astrophysics Data System (ADS)

Ge, Xinmin; Fan, Yiren; Liu, Jianyu; Zhang, Li; Han, Yujiao; Xing, Donghui

2017-10-01

Permeability is an important parameter in formation evaluation since it controls the fluid transportation of porous rocks. However, it is challengeable to compute the permeability of bioclastic limestone reservoirs by conventional methods linking petrophysical and geophysical data, due to the complex pore distributions. A new method is presented to estimate the permeability based on laboratory and downhole nuclear magnetic resonance (NMR) measurements. We divide the pore space into four intervals by the inflection points between the pore radius and the transversal relaxation time. Relationships between permeability and percentages of different pore intervals are investigated to investigate influential factors on the fluid transportation. Furthermore, an empirical model, which takes into account of the pore size distributions, is presented to compute the permeability. 212 core samples in our case show that the accuracy of permeability calculation is improved from 0.542 (SDR model), 0.507 (TIM model), 0.455 (conventional porosity-permeability regressions) to 0.803. To enhance the precision of downhole application of the new model, we developed a fluid correction algorithm to construct the water spectrum of in-situ NMR data, aiming to eliminate the influence of oil on the magnetization. The result reveals that permeability is positively correlated with percentages of mega-pores and macro-pores, but negatively correlated with the percentage of micro-pores. Poor correlation is observed between permeability and the percentage of meso-pores. NMR magnetizations and T2 spectrums after the fluid correction agree well with laboratory results for samples saturated with water. Field application indicates that the improved method provides better performance than conventional models such as Schlumberger-Doll Research equation, Timur-Coates equation, and porosity-permeability regressions.

Contaminant back-diffusion from low-permeability layers as affected by groundwater velocity: A laboratory investigation by box model and image analysis.

PubMed

Tatti, Fabio; Papini, Marco Petrangeli; Sappa, Giuseppe; Raboni, Massimo; Arjmand, Firoozeh; Viotti, Paolo

2018-05-01

Low-permeability lenses represent potential sources of long-term release when filled from contaminant solute through direct contact with dissolved plumes. The redistribution of contaminant from low to high permeability aquifer zones (Back-Diffusion) was studied. Redistribution causes a long plume tail, commonly regarded as one of the main obstacles to effective groundwater remediation. Laboratory tests were performed to reproduce the redistribution process and to investigate the effect of pumping water on the remediation time of these contaminated low-permeability lenses. The test section used is representative of clay/silt lenses (k≈1∗10 -10 m/s/k≈1∗10 -7 m/s) in a sand aquifer (k≈1∗10 -3 m/s). Hence, an image analysis procedure was used to estimate the diffusive flux of contaminant released by these low-permeability zones. The proposed technique was validated performing a mass balance of a lens saturated by a known quantity of tracer. For each test, performed using a different groundwater velocity, the diffusive fluxes of contaminant released by lenses were compared and the remediation times of the low-permeability zones calculated. For each lens, the obtained remediation timeframes were used to define an analytical relation vs groundwater velocity and the coefficients of these relations were matched to grain size of the low-permeability lenses. Results show that an increase of the velocity field is not useful to diminish the total depletion times as the process mainly diffusive. This is significant when the remediation approach relies on pumping technology. Copyright © 2017 Elsevier B.V. All rights reserved.

Do sediment type and test durations affect results of laboratory-based, accelerated testing studies of permeable pavement clogging?

PubMed

Nichols, Peter W B; White, Richard; Lucke, Terry

2015-04-01

Previous studies have attempted to quantify the clogging processes of Permeable Interlocking Concrete Pavers (PICPs) using accelerated testing methods. However, the results have been variable. This study investigated the effects that three different sediment types (natural and silica), and different simulated rainfall intensities, and testing durations had on the observed clogging processes (and measured surface infiltration rates) of laboratory-based, accelerated PICP testing studies. Results showed that accelerated simulated laboratory testing results are highly dependent on the type, and size of sediment used in the experiments. For example, when using real stormwater sediment up to 1.18 mm in size, the results showed that neither testing duration, nor stormwater application rate had any significant effect on PICP clogging. However, the study clearly showed that shorter testing durations generally increased clogging and reduced the surface infiltration rates of the models when artificial silica sediment was used. Longer testing durations also generally increased clogging of the models when using fine sediment (<300 μm). Results from this study will help researchers and designers better anticipate when and why PICPs are susceptible to clogging, reduce maintenance and extend the useful life of these increasingly common stormwater best management practices. Copyright © 2015 Elsevier B.V. All rights reserved.

A probabilistic damage model of stress-induced permeability anisotropy during cataclastic flow

NASA Astrophysics Data System (ADS)

Zhu, Wenlu; MontéSi, Laurent G. J.; Wong, Teng-Fong

2007-10-01

A fundamental understanding of the effect of stress on permeability evolution is important for many fault mechanics and reservoir engineering problems. Recent laboratory measurements demonstrate that in the cataclastic flow regime, the stress-induced anisotropic reduction of permeability in porous rocks can be separated into 3 different stages. In the elastic regime (stage I), permeability and porosity reduction are solely controlled by the effective mean stress, with negligible permeability anisotropy. Stage II starts at the onset of shear-enhanced compaction, when a critical yield stress is attained. In stage II, the deviatoric stress exerts primary control over permeability and porosity evolution. The increase in deviatoric stress results in drastic permeability and porosity reduction and considerable permeability anisotropy. The transition from stage II to stage III takes place progressively during the development of pervasive cataclastic flow. In stage III, permeability and porosity reduction becomes gradual again, and permeability anisotropy diminishes. Microstructural observations on deformed samples using laser confocal microscopy reveal that stress-induced microcracking and pore collapse are the primary forms of damage during cataclastic flow. A probabilistic damage model is formulated to characterize the effects of stress on permeability and its anisotropy. In our model, the effects of both effective mean stress and differential stress on permeability evolution are calculated. By introducing stress sensitivity coefficients, we propose a first-order description of the dependence of permeability evolution on different loading paths. Built upon the micromechanisms of deformation in porous rocks, this unified model provides new insight into the coupling of stress and permeability.

Permeability, storage and hydraulic diffusivity controlled by earthquakes

NASA Astrophysics Data System (ADS)

Brodsky, E. E.; Fulton, P. M.; Xue, L.

2016-12-01

Earthquakes can increase permeability in fractured rocks. In the farfield, such permeability increases are attributed to seismic waves and can last for months after the initial earthquake. Laboratory studies suggest that unclogging of fractures by the transient flow driven by seismic waves is a viable mechanism. These dynamic permeability increases may contribute to permeability enhancement in the seismic clouds accompanying hydraulic fracking. Permeability enhancement by seismic waves could potentially be engineered and the experiments suggest the process will be most effective at a preferred frequency. We have recently observed similar processes inside active fault zones after major earthquakes. A borehole observatory in the fault that generated the M9.0 2011 Tohoku earthquake reveals a sequence of temperature pulses during the secondary aftershock sequence of an M7.3 aftershock. The pulses are attributed to fluid advection by a flow through a zone of transiently increased permeability. Directly after the M7.3 earthquake, the newly damaged fault zone is highly susceptible to further permeability enhancement, but ultimately heals within a month and becomes no longer as sensitive. The observation suggests that the newly damaged fault zone is more prone to fluid pulsing than would be expected based on the long-term permeability structure. Even longer term healing is seen inside the fault zone of the 2008 M7.9 Wenchuan earthquake. The competition between damage and healing (or clogging and unclogging) results in dynamically controlled permeability, storage and hydraulic diffusivity. Recent measurements of in situ fault zone architecture at the 1-10 meter scale suggest that active fault zones often have hydraulic diffusivities near 10-2 m2/s. This uniformity is true even within the damage zone of the San Andreas fault where permeability and storage increases balance each other to achieve this value of diffusivity over a 400 m wide region. We speculate that fault zones

Determination of need for water soaking period in measurement of concrete volume of permeable voids : technical summary.

DOT National Transportation Integrated Search

2016-10-01

Water permeability of concrete is one of the key factors concerning : many concrete deterioration problems. It is often evaluated indirectly by : measuring the volume of permeable voids through the KT-73 (2012) testing : procedures. These procedures ...

TREATMENT OF INORGANIC CONTAMINANTS USING PERMEABLE REACTIVE BARRIERS

EPA Science Inventory

Permeable reactive barriers are an emerging alternative to traditional pump and treat systems for groundwater remediation. This technique has progressed rapidly over the past decade from laboratory bench-scale studies to full-scale implementation. Laboratory studies indicate the ...

Test device for measuring permeability of a barrier material

DOEpatents

Reese, Matthew; Dameron, Arrelaine; Kempe, Michael

2014-03-04

A test device for measuring permeability of a barrier material. An exemplary device comprises a test card having a thin-film conductor-pattern formed thereon and an edge seal which seals the test card to the barrier material. Another exemplary embodiment is an electrical calcium test device comprising: a test card an impermeable spacer, an edge seal which seals the test card to the spacer and an edge seal which seals the spacer to the barrier material.

Determination of need for water soaking period in measurement of concrete volume of permeable voids : final report.

DOT National Transportation Integrated Search

2016-10-01

Water permeability of concrete is one of the key factors concerning many concrete deterioration : problems. It is often evaluated indirectly by measuring the volume of permeable voids through the KT-73 : (2012) testing procedures. These procedures in...

Frictional stability-permeability relationships for fractures in shales: Friction-Permeability Relationships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Yi; Elsworth, Derek; Wang, Chaoyi

There is wide concern that fluid injection in the subsurface, such as for the stimulation of shale reservoirs or for geological CO 2 sequestration (GCS), has the potential to induce seismicity that may change reservoir permeability due to fault slip. However, the impact of induced seismicity on fracture permeability evolution remains unclear due to the spectrum of modes of fault reactivation (e.g., stable versus unstable). As seismicity is controlled by the frictional response of fractures, we explore friction-stability-permeability relationships through the concurrent measurement of frictional and hydraulic properties of artificial fractures in Green River shale (GRS) and Opalinus shale (OPS).more » We observe that carbonate-rich GRS shows higher frictional strength but weak neutral frictional stability. The GRS fracture permeability declines during shearing while an increased sliding velocity reduces the rate of permeability decline. By comparison, the phyllosilicate-rich OPS has lower friction and strong stability while the fracture permeability is reduced due to the swelling behavior that dominates over the shearing induced permeability reduction. Hence, we conclude that the friction-stability-permeability relationship of a fracture is largely controlled by mineral composition and that shale mineral compositions with strong frictional stability may be particularly subject to permanent permeability reduction during fluid infiltration.« less

Evaluation of methods for measuring relative permeability of anhydride from the Salado Formation: Sensitivity analysis and data reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christiansen, R.L.; Kalbus, J.S.; Howarth, S.M.

This report documents, demonstrates, evaluates, and provides theoretical justification for methods used to convert experimental data into relative permeability relationships. The report facilities accurate determination of relative permeabilities of anhydride rock samples from the Salado Formation at the Waste Isolation Pilot Plant (WIPP). Relative permeability characteristic curves are necessary for WIPP Performance Assessment (PA) predictions of the potential for flow of waste-generated gas from the repository and brine flow into repository. This report follows Christiansen and Howarth (1995), a comprehensive literature review of methods for measuring relative permeability. It focuses on unsteady-state experiments and describes five methods for obtaining relativemore » permeability relationships from unsteady-state experiments. Unsteady-state experimental methods were recommended for relative permeability measurements of low-permeability anhydrite rock samples form the Salado Formation because these tests produce accurate relative permeability information and take significantly less time to complete than steady-state tests. Five methods for obtaining relative permeability relationships from unsteady-state experiments are described: the Welge method, the Johnson-Bossler-Naumann method, the Jones-Roszelle method, the Ramakrishnan-Cappiello method, and the Hagoort method. A summary, an example of the calculations, and a theoretical justification are provided for each of the five methods. Displacements in porous media are numerically simulated for the calculation examples. The simulated product data were processed using the methods, and the relative permeabilities obtained were compared with those input to the numerical model. A variety of operating conditions were simulated to show sensitivity of production behavior to rock-fluid properties.« less

The permeability evolution of tuffisites and outgassing from dense rhyolitic magma

NASA Astrophysics Data System (ADS)

Heap, M. J.; Tuffen, H.; Wadsworth, F. B.; Reuschlé, T.; Castro, J. M.; Schipper, C. I.

2017-12-01

Recent observations of rhyolitic lava effusion from eruptions in Chile indicate that simultaneous pyroclastic venting facilitates outgassing. Venting from conduit-plugging lava domes is pulsatory and occurs through shallow fracture networks that deliver pyroclastic debris and exsolved gases to the surface. However, these fractures become blocked as the particulate fracture infill sinters viscously, thus drastically reducing permeability. Tuffisites, fossilized debris-filled fractures of this venting process, are abundant in pyroclastic material ejected during hybrid explosive-effusive activity. Dense tuffisite-hosting obsidian bombs ejected from Volcán Chaitén (Chile) in 2008 afford an opportunity to better understand the permeability evolution of tuffisites within low-permeability conduit plugs, wherein gas mobility is reliant upon fracture pathways. We use laboratory measurements of the permeability and porosity of tuffisites that preserve different degrees of sintering, combined with a grainsize-based sintering model and constraints on pressure-time paths from H2O diffusion, to place first-order constraints on tuffisite permeability evolution. Inferred timescales of sintering-driven tuffisite compaction and permeability loss, spanning minutes to hours, coincide with observed vent pulsations during hybrid rhyolitic activity and, more broadly, timescales of pressurization accompanying silicic lava dome extrusion. We therefore conclude that sintering exerts a first-order control on fracture-assisted outgassing from low-permeability, conduit-plugging silicic magma.

Measurements of pulmonary vascular permeability with PET and gallium-68 transferrin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mintun, M.A.; Dennis, D.R.; Welch, M.J.

1987-11-01

We quantified pulmonary vascular permeability with positron emission tomography (PET) and gallium-68-(/sup 68/Ga) labeled transferrin. Six dogs with oleic acid-induced lung injury confined to the left lower lobe, two normal human volunteers, and two patients with the adult respiratory distress syndrome (ARDS) were evaluated. Lung tissue-activity measurements were obtained from sequential 1-5 min PET scans collected over 60 min, after in vivo labeling of transferrin through intravenous administration of (/sup 68/Ga)citrate. Blood-activity measurements were measured from simultaneously obtained peripheral blood samples. A forward rate constant describing the movement of transferrin from pulmonary vascular to extravascular compartments, the pulmonary transcapillary escapemore » rate (PTCER), was then calculated from these data using a two-compartment model. In dogs, PTCER was 49 +/- 18 in normal lung tissue and 485 +/- 114 10(-4) min-1 in injured lung. A repeat study in these dogs 4 hr later showed no significant change. Values in the human subjects showed similarly marked differences between normal and abnormal lung tissue. We conclude that PET will be a useful method of evaluating vascular permeability changes after acute lung injury.« less

Permeability evolution governed by shear: An example during spine extrusion at Unzen volcano, Japan

NASA Astrophysics Data System (ADS)

Ashworth, James; Lavallée, Yan; Wallace, Paul; Kendrick, Jackie; Coats, Rebecca; Miwa, Takahiro; Hess, Kai-Uwe

2017-04-01

A volcano's eruptive style is strongly controlled by the permeability of the magma and the surrounding edifice rock - explosive activity is more likely if exsolved gases cannot escape the system. In this study, we investigate how shear strain causes variations in permeability within a volcanic conduit, and discuss how spatio-temporal variation in shear regimes may develop. The eruption of Unzen volcano, Japan, which occurred between 1990 - 1995, culminated in the extrusion of a 60 metre-high dacitic spine. The spine, left exposed at the lava dome surface, displays the petrographic architecture of the magma in the shallow conduit. Observations and measurements made in the field are combined with laboratory experiments to understand the distribution of permeability in the shallow conduit. Examination of the lava dome led to the selection of two sites for detailed investigation. First, we examined a section of extruded spine 6 metres in width, which displays a transition from apparently unsheared rock in the conduit core to rocks exhibiting increasing shear towards the conduit margin, bounded by a fault gouge zone. Laboratory characterisation (mineralogy, porosity, permeability, X-ray tomography) was undertaken on these samples. In contrast, a second section of spine (extruded later during the eruption) exhibited a large tensile fracture, and this area was investigated using non-destructive in-situ permeability measurements. Our lab measurements show that in the first outcrop, permeability decreases across the shear zone from core to gouge by approximately one order of magnitude perpendicular to shear; a similar decrease is observed parallel to shear, but is less severe. The lowest permeability is observed in the most highly sheared block; here, permeability is 2.5 x10-14 m2 in the plane of shear and 9 x10-15 m2 perpendicular to shear. Our measurements clearly demonstrate the influence of shear on conduit permeability, with significant anisotropy in the shear zone

Biopharmaceutics permeability classification of lorcaserin, a selective 5-hydroxytryptamine 2C agonist: method suitability and permeability class membership.

PubMed

Chen, Chuan; Ma, Michael G; Fullenwider, Cody L; Chen, Weichao G; Sadeque, Abu J M

2013-12-02

The objectives of the study were (1) to demonstrate that a Caco-2 cell-based permeability assay, developed in our laboratory, is suitable to identify the permeability classification according to the US Food and Drug Administration Biopharmaceutics Classification System guidance, and (2) to use the validated Caco-2 method to determine permeability class membership of lorcaserin. Lorcaserin, marketed in United States as Belviq, is a selective human 5-hydroxytryptamine 2C agonist used for weight management. First, the permeability of twenty commercially available drugs was determined in the apical-to-basolateral direction at a final concentration of 10 μM, with the pH of transporter buffer in the apical and basolateral compartments being 6.8 and 7.4, respectively. A rank-order relationship between in vitro permeability results and the extent of human intestinal absorption for the drugs tested was observed. Second, the apparent permeability coefficient values of lorcaserin at 2, 20, and 200 μM and apical pH values of 6.8 and 7.4 in the apical-to-basolateral direction were determined using the validated method and found to be comparable to those of the high-permeability internal standard metoprolol. Lorcaserin permeability across Caco-2 cell monolayers was not dependent on the variation of apical pH. Furthermore, lorcaserin was not a substrate for efflux transporters such as P-glycoprotein. In conclusion, using the validated Caco-2 permeability assay, it was shown that lorcaserin is a highly permeable compound.

High Resolution ground penetrating radar (GPR) measurements at the laboratory scale to model porosity and permeability in the Miami Limestone in South Florida.

NASA Astrophysics Data System (ADS)

Mount, G. J.; Comas, X.

2015-12-01

Subsurface water flow within the Biscayne aquifer is controlled by the heterogeneous distribution of porosity and permeability in the karst Miami Limestone and the presence of numerous dissolution and mega-porous features. The dissolution features and other high porosity areas can create preferential flow paths and direct recharge to the aquifer, which may not be accurately conceptualized in groundwater flow models. As hydrologic conditions are undergoing restoration in the Everglades, understanding the distribution of these high porosity areas within the subsurface would create a better understanding of subsurface flow. This research utilizes ground penetrating radar to estimate the spatial variability of porosity and dielectric permittivity of the Miami Limestone at centimeter scale resolution at the laboratory scale. High frequency GPR antennas were used to measure changes in electromagnetic wave velocity through limestone samples under varying volumetric water contents. The Complex Refractive Index Model (CRIM) was then applied in order to estimate porosity and dielectric permittivity of the solid phase of the limestone. Porosity estimates ranged from 45.2-66.0% from the CRIM model and correspond well with estimates of porosity from analytical and digital image techniques. Dielectric permittivity values of the limestone solid phase ranged from 7.0 and 13.0, which are similar to values in the literature. This research demonstrates the ability of GPR to identify the cm scale spatial variability of aquifer properties that influence subsurface water flow which could have implications for groundwater flow models in the Biscayne and potentially other shallow karst aquifers.

Pressure sensitivity of low permeability sandstones

USGS Publications Warehouse

Kilmer, N.H.; Morrow, N.R.; Pitman, Janet K.

1987-01-01

Detailed core analysis has been carried out on 32 tight sandstones with permeabilities ranging over four orders of magnitude (0.0002 to 4.8 mD at 5000 psi confining pressure). Relationships between gas permeability and net confining pressure were measured for cycles of loading and unloading. For some samples, permeabilities were measured both along and across bedding planes. Large variations in stress sensitivity of permeability were observed from one sample to another. The ratio of permeability at a nominal confining pressure of 500 psi to that at 5000 psi was used to define a stress sensitivity ratio. For a given sample, confining pressure vs permeability followed a linear log-log relationship, the slope of which provided an index of pressure sensitivity. This index, as obtained for first unloading data, was used in testing relationships between stress sensitivity and other measured rock properties. Pressure sensitivity tended to increase with increase in carbonate content and depth, and with decrease in porosity, permeability and sodium feldspar. However, scatter in these relationships increased as permeability decreased. Tests for correlations between pressure sensitivity and various linear combinations of variables are reported. Details of pore structure related to diagenetic changes appears to be of much greater significance to pressure sensitivity than mineral composition. ?? 1987.

Permeability determination through NMR detection of acoustically induced fluid oscillation.

PubMed

Looyestijn, Wim J; Smits, Robert M M; Abu-Shiekah, Issa; Kuvshinov, Boris; Hofman, Jan P; Schwing, Alex

2006-11-01

We present a novel approach for directly measuring the permeability of reservoir rocks by an instrument lowered in a well bore. The measurement is made by creating an oscillatory motion of fluids in the pores by acoustic stimulation and by detecting the amplitude response as a phase shift on a nuclear magnetic resonance relaxation signal. A full theoretical description is given. The feasibility of the method has been verified in the laboratory on a set of sandstone and carbonate samples spanning the entire range of practical interest.

Permeability-porosity relationships of subduction zone sediments

USGS Publications Warehouse

Gamage, Kusali; Screaton, Elizabeth; Bekins, B.; Aiello, I.

2011-01-01

Permeability-porosity relationships for sediments from the northern Barbados, Costa Rica, Nankai, and Peru subduction zones were examined based on sediment type, grain size distribution, and general mechanical and chemical compaction history. Greater correlation was observed between permeability and porosity in siliciclastic sediments, diatom oozes, and nannofossil chalks than in nannofossil oozes. For siliciclastic sediments, grouping of sediments by percentage of clay-sized material yields relationships that are generally consistent with results from other marine settings and suggests decreasing permeability as percentage of clay-sized material increases. Correction of measured porosities for smectite content improved the correlation of permeability-porosity relationships for siliciclastic sediments and diatom oozes. The relationship between permeability and porosity for diatom oozes is very similar to the relationship in siliciclastic sediments, and permeabilities of both sediment types are related to the amount of clay-size particles. In contrast, nannofossil oozes have higher permeability values by 1.5 orders of magnitude than siliciclastic sediments of the same porosity and show poor correlation between permeability and porosity. More indurated calcareous sediments, nannofossil chalks, overlap siliciclastic permeabilities at the lower end of their measured permeability range, suggesting similar consolidation patterns at depth. Thus, the lack of correlation between permeability and porosity for nannofossil oozes is likely related to variations in mechanical and chemical compaction at shallow depths. This study provides the foundation for a much-needed global database with fundamental properties that relate to permeability in marine settings. Further progress in delineating controls on permeability requires additional carefully documented permeability measurements on well-characterized samples. ?? 2010 Elsevier B.V.

Hydrogen Permeability of Incoloy 800H, Inconel 617, and Haynes 230 Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pattrick Calderoni

A potential issue in the design of the NGNP reactor and high-temperature components is the permeation of fission generated tritium and hydrogen product from downstream hydrogen generation through high-temperature components. Such permeation can result in the loss of fission-generated tritium to the environment and the potential contamination of the helium coolant by permeation of product hydrogen into the coolant system. The issue will be addressed in the engineering design phase, and requires knowledge of permeation characteristics of the candidate alloys. Of three potential candidates for high-temperature components of the NGNP reactor design, the hydrogen permeability has been documented well onlymore » for Incoloy 800H, but at relatively high partial pressures of hydrogen. Hydrogen permeability data have been published for Inconel 617, but only in two literature reports and for partial pressures of hydrogen greater than one atmosphere, far higher than anticipated in the NGNP reactor. The hydrogen permeability of Haynes 230 has not been published. To support engineering design of the NGNP reactor components, the hydrogen permeability of Inconel 617 and Haynes 230 were determined using a measurement system designed and fabricated at the Idaho National Laboratory. The performance of the system was validated using Incoloy 800H as reference material, for which the permeability has been published in several journal articles. The permeability of Incoloy 800H, Inconel 617 and Haynes 230 was measured in the temperature range 650 to 950 °C and at hydrogen partial pressures of 10-3 and 10-2 atm, substantially lower pressures than used in the published reports. The measured hydrogen permeability of Incoloy 800H and Inconel 617 were in good agreement with published values obtained at higher partial pressures of hydrogen. The hydrogen permeability of Inconel 617 and Haynes 230 were similar, about 50% greater than for Incoloy 800H and with similar temperature dependence.« less

Tortuous pathways: Fundamental characterisation of the anisotropic permeability through clay-rich shales from macro- to nano-scale.

NASA Astrophysics Data System (ADS)

Mitchell, T. M.; Backeberg, N. R.; Iacoviello, F.; Rittner, M.; Jones, A. P.; Wheeler, J.; Day, R.; Vermeesch, P.; Shearing, P. R.; Striolo, A.

2017-12-01

The permeability of shales is important, because it controls where oil and gas resources can migrate to and where in the Earth hydrocarbons are ultimately stored. Shales have a well-known anisotropic directional permeability that is inherited from the depositional layering of sedimentary laminations, where the highest permeability is measured parallel to laminations and the lowest permeability is perpendicular to laminations. We combine state of the art laboratory permeability experiments with high-resolution X-ray computed tomography and for the first time can quantify the three-dimensional interconnected pathways through a rock that define the anisotropic behaviour of shales. Experiments record a physical anisotropy in permeability of one to two orders of magnitude. Two- and three-dimensional analyses of micro- and nano-scale X-ray computed tomography illuminate that the directional anisotropy is fundamentally controlled by the bulk rock mineral geometry, which determines the finite length (or tortuosity) of the interconnected pathways through the porous/permeable phases in shales. Understanding the mineral-scale control on permeability will allow for better estimations of the extent of recoverable reserves in shale gas plays globally.

Deepwater Gulf of Mexico turbidites -- Compaction effects on porosity and permeability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ostermeier, R.M.

1995-06-01

The deepwater Gulf of Mexico is now a major area of activity for the US oil industry. Compaction causes particular concern because most prospective deepwater reservoirs are highly geo-pressured and many have limited aquifer support; water injection may also be problematic. To address some of the issues associated with compaction, the authors initiated a special core-analysis program to study compaction effects on turbidite sand porosity and permeability specifically. This program also addressed a number of subsidiary but no less important issues, such as sample characterization and quality, sample preparation, and test procedures. These issues are particularly pertinent, because Gulf ofmore » Mexico turbidites are generally unconsolidated, loose sands, and are thus susceptible to a whole array of potentially serious core-disturbing processes. One key result of the special core analysis program is that turbidite compressibilities exhibit large variations in both magnitude and stress dependence. These variations correlate with creep response in the laboratory measurements. The effects of compaction on permeability are significant. To eliminate complicating effects caused by fines movement, the authors made oil flow measurements at initial water saturation. The measurements indicate compaction reduces permeability four to five times more than porosity on a relative basis.« less

Development of an evaporation-optimized and water-permeable pavement

NASA Astrophysics Data System (ADS)

Starke, P.; Göbel, P.; Coldewey, W. G.

2009-04-01

the soil-mechanics laboratory of the University of Muenster. For their street construction useability, and having regard to evaporation, a selection of appropriate materials were built into a test field. The test field consisted of seven hexagonal areas each about 10 m2 large, which are placed in a honeycomb manner. The evaporation measurements are carried out with a WERNER tunnel-evaporation gauge (TUV) which is able to detect the actual evaporation rate. Its functional principle also allows a direct comparison between the middle reference area and one outer area of the test field. Every measuring period lasts one week and after that the TUV is moved to between the next outer area and the reference area. So the TUV rotates over the whole test field and every measuring area is covered by a measurement. In addition, a Hellman rain-gauge near the test field enables the measurement of a direct precipitation-evaporation ratio. Since the start of the measurements in July 2008, the first results collected showed that measureable differences in evaporation rates could be detected after a few measuring periods, i.e. the differences are up to 32% between the reference area and one outer area. In July 2009, the six outer measuring areas of the test field will be replaced and, based on the actual results collected, the sub-base layers will be replaced by an evaporation-optimized sub-base. The new outer measuring areas will only differ in terms of a different paving-stone surface. These paving stones are actually under developement and under laboratory testing (i.e. permeability, porosity, capillary water and evaporationrates), and so they will be evaporation-opimized. The open-air test in the test field is to assure and compare the evaporation rates. As a final result, the evaporation-optimized and water-permeable pavement and the knowledge of its exact drainage ratio will allow city planners or architects to build water-permeable streets with due regard to the respective area

A transmission line method for the measurement of microwave permittivity and permeability

NASA Astrophysics Data System (ADS)

Lederer, P. G.

1990-12-01

A method for determining complex permittivity and permeability at microwave frequencies from two port S parameter measurements of lossy solids in coaxial or waveguide transmission lines is described. The use of the TRL (Through Reflect Line) calibration scheme allows the measuring system to be calibrated right up to the specimen faces thereby eliminating most of the sample cell from the measurement and allowing suitable materials to be molded directly into the specimen cell in order to eliminate air gaps between specimen and transmission line walls. Some illustrative measurements for dielectric and magnetic materials are presented.

Modelling of Longwall Mining-Induced Strata Permeability Change

NASA Astrophysics Data System (ADS)

Adhikary, D. P.; Guo, H.

2015-01-01

The field measurement of permeability within the strata affected by mining is a challenging and expensive task, thus such tests may not be carried out in large numbers to cover all the overburden strata and coal seams being affected by mining. However, numerical modelling in conjunction with a limited number of targeted field measurements can be used efficiently in assessing the impact of mining on a regional scale. This paper presents the results of underground packer testing undertaken at a mine site in New South Wales in Australia and numerical simulations conducted to assess the mining-induced strata permeability change. The underground packer test results indicated that the drivage of main headings (roadways) had induced a significant change in permeability into the solid coal barrier. Permeability increased by more than 50 times at a distance of 11.2-11.5 m from the roadway rib into the solid coal barrier. The tests conducted in the roof strata above the longwall goaf indicated more than 1,000-fold increase in permeability. The measured permeability values varied widely and strangely on a number of occasions; for example the test conducted from the main headings at the 8.2-8.5 m test section in the solid coal barrier showed a decline in permeability value as compared to that at the 11.2-11.5 m section contrary to the expectations. It is envisaged that a number of factors during the tests might have had affected the measured values of permeability: (a) swelling and smearing of the borehole, possibly lowering the permeability values; (b) packer bypass by larger fractures; (c) test section lying in small but intact (without fractures) rock segment, possibly resulting in lower permeability values; and (d) test section lying right at the extensive fractures, possibly measuring higher permeability values. Once the anomalous measurement data were discarded, the numerical model results could be seen to match the remaining field permeability measurement data

Permeability Sensitivity Functions and Rapid Simulation of Hydraulic-Testing Measurements Using Perturbation Theory

NASA Astrophysics Data System (ADS)

Escobar Gómez, J. D.; Torres-Verdín, C.

2018-03-01

Single-well pressure-diffusion simulators enable improved quantitative understanding of hydraulic-testing measurements in the presence of arbitrary spatial variations of rock properties. Simulators of this type implement robust numerical algorithms which are often computationally expensive, thereby making the solution of the forward modeling problem onerous and inefficient. We introduce a time-domain perturbation theory for anisotropic permeable media to efficiently and accurately approximate the transient pressure response of spatially complex aquifers. Although theoretically valid for any spatially dependent rock/fluid property, our single-phase flow study emphasizes arbitrary spatial variations of permeability and anisotropy, which constitute key objectives of hydraulic-testing operations. Contrary to time-honored techniques, the perturbation method invokes pressure-flow deconvolution to compute the background medium's permeability sensitivity function (PSF) with a single numerical simulation run. Subsequently, the first-order term of the perturbed solution is obtained by solving an integral equation that weighs the spatial variations of permeability with the spatial-dependent and time-dependent PSF. Finally, discrete convolution transforms the constant-flow approximation to arbitrary multirate conditions. Multidimensional numerical simulation studies for a wide range of single-well field conditions indicate that perturbed solutions can be computed in less than a few CPU seconds with relative errors in pressure of <5%, corresponding to perturbations in background permeability of up to two orders of magnitude. Our work confirms that the proposed joint perturbation-convolution (JPC) method is an efficient alternative to analytical and numerical solutions for accurate modeling of pressure-diffusion phenomena induced by Neumann or Dirichlet boundary conditions.

Polymer as Permeability Modifier in Porous Media

NASA Astrophysics Data System (ADS)

Parsa, S.; Weitz, D.

2017-12-01

Polymer flow through porous media is of particular interest in applications such as enhanced oil recovery and ground water remediation. We measure the effects of polymer flow on the permeability and local velocity distribution of a single phase flow in 3D micromodel of porous media using confocal microscopy and bulk permeability measurement. Our measurements show considerable reduction in permeability and increased velocity fluctuations with fluid velocities being diverted in some pores after polymer flow. We also find that the average velocity in the medium at constant imposed flow rate scales with the inverse square root of permeability.

Tectonic significance of porosity and permeability regimes in the red beds formations of the South Georgia Rift Basin

NASA Astrophysics Data System (ADS)

Akintunde, Olusoga M.; Knapp, Camelia C.; Knapp, James H.

2014-09-01

A simple, new porosity/permeability-depth profile was developed from available laboratory measurements on Triassic sedimentary red beds (sandstone) from parts of the South Georgia Rift (SGR) basin in order to investigate the feasibility for long-term CO2 storage. The study locations were: Sumter, Berkeley, Dunbarton, Clubhouse Crossroad-3 (CC-3) and Norris Lightsey wells. As expected, both porosity and permeability show changes with depth at the regional scale that was much greater than at local scale. The significant changes in porosity and permeability with depth suggest a highly compacted, deformed basin, and potentially, a history of uplift and erosion. The permeability is generally low both at shallow (less than 1826 ft/556.56 m) and deeper depths (greater than 1826 ft/556.56 m). Both porosity and permeability follow the normal trend, decreasing linearly with depth for most parts of the study locations with the exception of the Norris Lightsey well. A petrophysical study on a suite of well logs penetrating the Norris Lightsey red beds at depths sampled by the core-derived laboratory measurements shows an abnormal shift (by 50%) in the acoustic travel time and/or in the sonic-derived P-wave velocity that indicates possible faulting or fracturing at depth. The departure of the Norris Lightsey's porosities and permeabilities from the normal compaction trend may be a consequence of the existence of a fault/fracture controlled abnormal pressure condition at depth. The linear and non-linear behaviors of the porosity/permeability distribution throughout the basin imply the composition of the SGR red beds, and by extension analog/similar Triassic-Jurassic formations within the Eastern North American Margin have been altered by compaction, uplift, erosion and possible faulting that have shaped the evolution of these Triassic formations following the major phase of rifting.

Ground-water flow in low permeability environments

USGS Publications Warehouse

Neuzil, Christopher E.

1986-01-01

Certain geologic media are known to have small permeability; subsurface environments composed of these media and lacking well developed secondary permeability have groundwater flow sytems with many distinctive characteristics. Moreover, groundwater flow in these environments appears to influence the evolution of certain hydrologic, geologic, and geochemical systems, may affect the accumulation of pertroleum and ores, and probably has a role in the structural evolution of parts of the crust. Such environments are also important in the context of waste disposal. This review attempts to synthesize the diverse contributions of various disciplines to the problem of flow in low-permeability environments. Problems hindering analysis are enumerated together with suggested approaches to overcoming them. A common thread running through the discussion is the significance of size- and time-scale limitations of the ability to directly observe flow behavior and make measurements of parameters. These limitations have resulted in rather distinct small- and large-scale approaches to the problem. The first part of the review considers experimental investigations of low-permeability flow, including in situ testing; these are generally conducted on temporal and spatial scales which are relatively small compared with those of interest. Results from this work have provided increasingly detailed information about many aspects of the flow but leave certain questions unanswered. Recent advances in laboratory and in situ testing techniques have permitted measurements of permeability and storage properties in progressively “tighter” media and investigation of transient flow under these conditions. However, very large hydraulic gradients are still required for the tests; an observational gap exists for typical in situ gradients. The applicability of Darcy's law in this range is therefore untested, although claims of observed non-Darcian behavior appear flawed. Two important nonhydraulic

Studying the Variation in Gas Permeability of Porous Building Substrates

NASA Astrophysics Data System (ADS)

Townsend, L.; Savidge, C. R.; Hu, L.; Rizzo, D. M.; Hayden, N. J.; Dewoolkar, M.

2009-12-01

Understanding permeability of building materials is important for problems involving studies of contaminant transport. Examples include contamination from fire, acid rain, and chemical and biological weapons. Our research investigates the gas permeability of porous building substrates such as concretes, limestones, sandstones, and bricks. Each sample was cored to produce 70 mm (2.75”) diameter cores approximately 75-130 mm (3-5”) tall. The surface gas permeability was measured on the top surface of these specimens using the AutoScan II device manufactured by New England Research, Inc. The measurements were taken along a 3 mm grid producing a map of surface gas permeability. An example map is shown in Figure 1. The macroscopic measurements were performed along the entire cored specimen. A second set of measurements were made on a 5 mm thick slice cut from the top of each specimen to examine whether these measurements compare better with the surface measurements. The macroscopic gas permeability was measured for all specimens using ASTM D 4525. The results are summarized in Table 1. In general, the surface and macroscopic gas permeability measurements (Table 1) compare reasonably well (within one order of magnitude). The permeability of the 5 mm slices is not significantly different from the entire core for the specimens tested. Figure 1. Results of surface permeability mappingof Ohio Sandstone using the AutoScan II device. a) Map of gas permeability b) Range of gas permeability c) Density function of permeability. Table 1. Gas permeability values (mD)

I-55 OGFC field permeability testing.

DOT National Transportation Integrated Search

2009-12-01

An OGFC test section was constructed on I-55 in Copiah County, MS during the : spring/summer of 2007. As part of the study, literature was reviewed and a falling head : permeability device was identified that has been used in laboratory and field stu...

Study on road surface source pollution controlled by permeable pavement

NASA Astrophysics Data System (ADS)

Zheng, Chaocheng

2018-06-01

The increase of impermeable pavement in urban construction not only increases the runoff of the pavement, but also produces a large number of Non-Point Source Pollution. In the process of controlling road surface runoff by permeable pavement, a large number of particulate matter will be withheld when rainwater is being infiltrated, so as to control the source pollution at the source. In this experiment, we determined the effect of permeable road surface to remove heavy pollutants in the laboratory and discussed the related factors that affect the non-point pollution of permeable pavement, so as to provide a theoretical basis for the application of permeable pavement.

Investigation of uncertainty in CO 2 reservoir models: A sensitivity analysis of relative permeability parameter values

DOE PAGES

Yoshida, Nozomu; Levine, Jonathan S.; Stauffer, Philip H.

2016-03-22

Numerical reservoir models of CO 2 injection in saline formations rely on parameterization of laboratory-measured pore-scale processes. Here, we have performed a parameter sensitivity study and Monte Carlo simulations to determine the normalized change in total CO 2 injected using the finite element heat and mass-transfer code (FEHM) numerical reservoir simulator. Experimentally measured relative permeability parameter values were used to generate distribution functions for parameter sampling. The parameter sensitivity study analyzed five different levels for each of the relative permeability model parameters. All but one of the parameters changed the CO 2 injectivity by <10%, less than the geostatistical uncertainty that applies to all large subsurface systems due to natural geophysical variability and inherently small sample sizes. The exception was the end-point CO 2 relative permeability, kmore » $$0\\atop{r}$$ CO2, the maximum attainable effective CO 2 permeability during CO 2 invasion, which changed CO2 injectivity by as much as 80%. Similarly, Monte Carlo simulation using 1000 realizations of relative permeability parameters showed no relationship between CO 2 injectivity and any of the parameters but k$$0\\atop{r}$$ CO2, which had a very strong (R 2 = 0.9685) power law relationship with total CO 2 injected. Model sensitivity to k$$0\\atop{r}$$ CO2 points to the importance of accurate core flood and wettability measurements.« less

Investigation of uncertainty in CO 2 reservoir models: A sensitivity analysis of relative permeability parameter values

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshida, Nozomu; Levine, Jonathan S.; Stauffer, Philip H.

Numerical reservoir models of CO 2 injection in saline formations rely on parameterization of laboratory-measured pore-scale processes. Here, we have performed a parameter sensitivity study and Monte Carlo simulations to determine the normalized change in total CO 2 injected using the finite element heat and mass-transfer code (FEHM) numerical reservoir simulator. Experimentally measured relative permeability parameter values were used to generate distribution functions for parameter sampling. The parameter sensitivity study analyzed five different levels for each of the relative permeability model parameters. All but one of the parameters changed the CO 2 injectivity by <10%, less than the geostatistical uncertainty that applies to all large subsurface systems due to natural geophysical variability and inherently small sample sizes. The exception was the end-point CO 2 relative permeability, kmore » $$0\\atop{r}$$ CO2, the maximum attainable effective CO 2 permeability during CO 2 invasion, which changed CO2 injectivity by as much as 80%. Similarly, Monte Carlo simulation using 1000 realizations of relative permeability parameters showed no relationship between CO 2 injectivity and any of the parameters but k$$0\\atop{r}$$ CO2, which had a very strong (R 2 = 0.9685) power law relationship with total CO 2 injected. Model sensitivity to k$$0\\atop{r}$$ CO2 points to the importance of accurate core flood and wettability measurements.« less

System and method for measuring permeability of materials

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John

2013-07-09

Systems and methods are provided for measuring the permeance of a material. The permeability of the material may also be derived. Systems typically provide a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Discontinuities in effective permeability due to fracture percolation

DOE PAGES

Hyman, Jeffrey De'Haven; Karra, Satish; Carey, James William; ...

2018-01-31

Motivated by a triaxial coreflood experiment with a sample of Utica shale where an abrupt jump in permeability was observed, possibly due to the creation of a percolating fracture network through the sample, we perform numerical simulations based on the experiment to characterize how the effective permeability of otherwise low-permeability porous media depends on fracture formation, connectivity, and the contrast between the fracture and matrix permeabilities. While a change in effective permeability due to fracture formation is expected, the dependence of its magnitude upon the contrast between the matrix permeability and fracture permeability and the fracture network structure is poorlymore » characterized. We use two different high-fidelity fracture network models to characterize how effective permeability changes as percolation occurs. The first is a dynamic two-dimensional fracture propagation model designed to mimic the laboratory settings of the experiment. The second is a static three-dimensional discrete fracture network (DFN) model, whose fracture and network statistics are based on the fractured sample of Utica shale. Once the network connects the inflow and outflow boundaries, the effective permeability increases non-linearly with network density. In most networks considered, a jump in the effective permeability was observed when the embedded fracture network percolated. We characterize how the magnitude of the jump, should it occur, depends on the contrast between the fracture and matrix permeabilities. For small contrasts between the matrix and fracture permeabilities the change is insignificant. However, for larger contrasts, there is a substantial jump whose magnitude depends non-linearly on the difference between matrix and fracture permeabilities. A power-law relationship between the size of the jump and the difference between the matrix and fracture permeabilities is observed. In conclusion, the presented results underscore the importance of

Discontinuities in effective permeability due to fracture percolation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyman, Jeffrey De'Haven; Karra, Satish; Carey, James William

Motivated by a triaxial coreflood experiment with a sample of Utica shale where an abrupt jump in permeability was observed, possibly due to the creation of a percolating fracture network through the sample, we perform numerical simulations based on the experiment to characterize how the effective permeability of otherwise low-permeability porous media depends on fracture formation, connectivity, and the contrast between the fracture and matrix permeabilities. While a change in effective permeability due to fracture formation is expected, the dependence of its magnitude upon the contrast between the matrix permeability and fracture permeability and the fracture network structure is poorlymore » characterized. We use two different high-fidelity fracture network models to characterize how effective permeability changes as percolation occurs. The first is a dynamic two-dimensional fracture propagation model designed to mimic the laboratory settings of the experiment. The second is a static three-dimensional discrete fracture network (DFN) model, whose fracture and network statistics are based on the fractured sample of Utica shale. Once the network connects the inflow and outflow boundaries, the effective permeability increases non-linearly with network density. In most networks considered, a jump in the effective permeability was observed when the embedded fracture network percolated. We characterize how the magnitude of the jump, should it occur, depends on the contrast between the fracture and matrix permeabilities. For small contrasts between the matrix and fracture permeabilities the change is insignificant. However, for larger contrasts, there is a substantial jump whose magnitude depends non-linearly on the difference between matrix and fracture permeabilities. A power-law relationship between the size of the jump and the difference between the matrix and fracture permeabilities is observed. In conclusion, the presented results underscore the importance of

Investigation on porosity and permeability change of Mount Simon sandstone (Knox County, IN, USA) under geological CO 2 sequestration conditions: a numerical simulation approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Liwei; Soong, Yee; Dilmore, Robert M.

In this paper, a numerical model was developed to simulate reactive transport with porosity and permeability change of Mount Simon sandstone (samples from Knox County, IN) after 180 days of exposure to CO 2-saturated brine under CO 2 sequestration conditions. The model predicted formation of a high-porosity zone adjacent to the surface of the sample in contact with bulk brine, and a lower porosity zone just beyond that high-porosity zone along the path from sample/bulk brine interface to sample core. The formation of the high porosity zone was attributed to dissolution of quartz and muscovite/illite, while the formation of themore » lower porosity zone adjacent to the aforementioned high porosity zone was attributed to precipitation of kaolinite and feldspar. The model predicted a 40% permeability increase for the Knox sandstone sample after 180 days of exposure to CO 2-saturated brine, which was consistent with laboratory-measured permeability results. Model-predicted solution chemistry results were also found to be consistent with laboratory-measured solution chemistry data. Finally, initial porosity, initial feldspar content and the exponent n value (determined by pore structure and tortuosity) used in permeability calculations were three important factors affecting permeability evolution of sandstone samples under CO 2 sequestration conditions.« less

Investigation on porosity and permeability change of Mount Simon sandstone (Knox County, IN, USA) under geological CO 2 sequestration conditions: a numerical simulation approach

DOE PAGES

Zhang, Liwei; Soong, Yee; Dilmore, Robert M.

2016-01-14

In this paper, a numerical model was developed to simulate reactive transport with porosity and permeability change of Mount Simon sandstone (samples from Knox County, IN) after 180 days of exposure to CO 2-saturated brine under CO 2 sequestration conditions. The model predicted formation of a high-porosity zone adjacent to the surface of the sample in contact with bulk brine, and a lower porosity zone just beyond that high-porosity zone along the path from sample/bulk brine interface to sample core. The formation of the high porosity zone was attributed to dissolution of quartz and muscovite/illite, while the formation of themore » lower porosity zone adjacent to the aforementioned high porosity zone was attributed to precipitation of kaolinite and feldspar. The model predicted a 40% permeability increase for the Knox sandstone sample after 180 days of exposure to CO 2-saturated brine, which was consistent with laboratory-measured permeability results. Model-predicted solution chemistry results were also found to be consistent with laboratory-measured solution chemistry data. Finally, initial porosity, initial feldspar content and the exponent n value (determined by pore structure and tortuosity) used in permeability calculations were three important factors affecting permeability evolution of sandstone samples under CO 2 sequestration conditions.« less

Permeability of cork to gases.

PubMed

Faria, David P; Fonseca, Ana L; Pereira, Helen; Teodoro, Orlando M N D

2011-04-27

The permeability of gases through uncompressed cork was investigated. More than 100 samples were assessed from different plank qualities to provide a picture of the permeability distribution. A novel technique based on a mass spectrometer leak detector was used to directly measure the helium flow through the central area of small disks 10 mm in diameter and 2 mm thick. The permeability for nitrogen, oxygen, and other gases was measured by the pressure rise technique. Boiled and nonboiled cork samples from different sections were evaluated. An asymmetric frequency distribution ranging 3 orders of magnitude (roughly from 1 to 1000 μmol/(cm·atm·day)) for selected samples without macroscopic defects was found, having a peak below 100 μmol/(cm·atm·day). Correlation was found between density and permeability: higher density samples tend to show lower permeability. However, boiled cork showed a mean lower permeability despite having a lower density. The transport mechanism of gases through cork was also examined. Calculations suggest that gases permeate uncompressed cork mainly through small channels between cells under a molecular flow regime. The diameter of such channels was estimated to be in the range of 100 nm, in agreement with the plasmodesmata size in the cork cell walls.

Permeability anisotropy in marine mudstones in the Nankai Trough, SW Japan: Implications for hypothesized lateral fluid flow and chemical transport outboard of the trench

NASA Astrophysics Data System (ADS)

Saffer, D. M.; McKiernan, A. W.; Skarbek, R. M.

2008-12-01

Characterizing dewatering pathways and chemical fluxes near and outboard of subduction trenches is important toward understanding early sediment dewatering and devolatilization. Quantifying fluid flow rates also constrains the hydraulic gradients driving flow, and thus ultimately hold implications for pore pressure distribution and fault mechanical strength. We focus on the well-studied Nankai Trough offshore SW Japan, where drilling has sampled the sedimentary section at several boreholes from ~11 km outboard of the trench to 3 km landward. At these drillsites, &δ37Cl data and correlation of distinct extrema in downhole chloride profiles have been interpreted to reflect substantial horizontal fluid flow to >10 km outboard of the trench within the ~400 m-thick, homogeneous Lower Shikoku Basin (LSB) facies mudstone. The estimated horizontal velocities are 13 ± 5 cm yr-1; the flow is presumably driven by loading during subduction, and mediated by either permeable conduits or strong anisotropy in permeability. However, the pressure gradients and sediment permeabilities necessary for such flow have not been quantified. Here, we address this problem by combining (1) laboratory measurement of horizontal and vertical sediment permeability from a combination of constant rate of strain (CRS) consolidation tests and flow-through measurements on core samples; and (2) numerical models of fluid flow within a cross section perpendicular to the trench. In our models, we assign hydrostatic pressure at the top and seaward edges, a no-flow condition at the base of the sediments, and pore pressures ranging from 40%-100% of lithostatic at the arcward model boundary. We assign sediment permeability on the basis of our laboratory measurements, and evaluate the possible role of thin permeable conduits as well as strong anisotropy in the incoming section. Our laboratory results define a systematic log-linear relationship between sediment permeability and porosity within the LSB

[Study on the influence of bioclogging on permeability of saturated porous media by experiments and models].

PubMed

Yang, Jing; Ye, Shu-jun; Wu, Ji-chun

2011-05-01

This paper studied on the influence of bioclogging on permeability of saturated porous media. Laboratory hydraulic tests were conducted in a two-dimensional C190 sand-filled cell (55 cm wide x 45 cm high x 1.28 cm thick) to investigate growth of the mixed microorganisms (KB-1) and influence of biofilm on permeability of saturated porous media under condition of rich nutrition. Biomass distributions in the water and on the sand in the cell were measured by protein analysis. The biofilm distribution on the sand was observed by confocal laser scanning microscopy. Permeability was measured by hydraulic tests. The biomass levels measured in water and on the sand increased with time, and were highest at the bottom of the cell. The biofilm on the sand at the bottom of the cell was thicker. The results of the hydraulic tests demonstrated that the permeability due to biofilm growth was estimated to be average 12% of the initial value. To investigate the spatial distribution of permeability in the two dimensional cell, three models (Taylor, Seki, and Clement) were used to calculate permeability of porous media with biofilm growth. The results of Taylor's model showed reduction in permeability of 2-5 orders magnitude. The Clement's model predicted 3%-98% of the initial value. Seki's model could not be applied in this study. Conclusively, biofilm growth could obviously decrease the permeability of two dimensional saturated porous media, however, the reduction was much less than that estimated in one dimensional condition. Additionally, under condition of two dimensional saturated porous media with rich nutrition, Seki's model could not be applied, Taylor's model predicted bigger reductions, and the results of Clement's model were closest to the result of hydraulic test.

Sub-core permeability and relative permeability characterization with Positron Emission Tomography

NASA Astrophysics Data System (ADS)

Zahasky, C.; Benson, S. M.

2017-12-01

This study utilizes preclinical micro-Positron Emission Tomography (PET) to image and quantify the transport behavior of pulses of a conservative aqueous radiotracer injected during single and multiphase flow experiments in a Berea sandstone core with axial parallel bedding heterogeneity. The core is discretized into streamtubes, and using the micro-PET data, expressions are derived from spatial moment analysis for calculating sub-core scale tracer flux and pore water velocity. Using the flux and velocity data, it is then possible to calculate porosity and saturation from volumetric flux balance, and calculate permeability and water relative permeability from Darcy's law. Full 3D simulations are then constructed based on this core characterization. Simulation results are compared with experimental results in order to test the assumptions of the simple streamtube model. Errors and limitations of this analysis will be discussed. These new methods of imaging and sub-core permeability and relative permeability measurements enable experimental quantification of transport behavior across scales.

Geologic Sequestration of CO2: Potential Permeability Changes in Host Formations of the San Juan Basin, New Mexico

NASA Astrophysics Data System (ADS)

Abel, A. P.; McPherson, B.; Lichtner, P.; Bond, G.; Stringer, J.; Grigg, R.

2002-12-01

Sandstone. In addition to relative permeability, we are conducting longer-term flow tests reflecting marked permeability changes, and documenting the changes by comparing detailed pre-test measurements of porosity and permeability to post-test measurements. We are using these experimental results to parameterize coupled-flow and reactive-chemistry models of a selected cross-section of the San Juan basin. Our flow and chemistry model is based on the Los Alamos National Laboratory reactive chemistry simulator, TRANS, coupled to the Lawrence Berkeley Laboratory flow simulator, TOUGH2. The purpose of these simulation models is to evaluate potential CO2- and bicarbonate-induced diagenetic changes in permeability and flow at the basin-scale. In addition they will provide useful information in relation to brine extraction. We are also using these calibrated basin models to examine natural diagenesis and permeability evolution associated with changing brine properties and flow conditions over geologic time.

Multiparameter Analysis of Gas Transport Phenomena in Shale Gas Reservoirs: Apparent Permeability Characterization.

PubMed

Shen, Yinghao; Pang, Yu; Shen, Ziqi; Tian, Yuanyuan; Ge, Hongkui

2018-02-08

The large amount of nanoscale pores in shale results in the inability to apply Darcy's law. Moreover, the gas adsorption of shale increases the complexity of pore size characterization and thus decreases the accuracy of flow regime estimation. In this study, an apparent permeability model, which describes the adsorptive gas flow behavior in shale by considering the effects of gas adsorption, stress dependence, and non-Darcy flow, is proposed. The pore size distribution, methane adsorption capacity, pore compressibility, and matrix permeability of the Barnett and Eagle Ford shales are measured in the laboratory to determine the critical parameters of gas transport phenomena. The slip coefficients, tortuosity, and surface diffusivity are predicted via the regression analysis of the permeability data. The results indicate that the apparent permeability model, which considers second-order gas slippage, Knudsen diffusion, and surface diffusion, could describe the gas flow behavior in the transition flow regime for nanoporous shale. Second-order gas slippage and surface diffusion play key roles in the gas flow in nanopores for Knudsen numbers ranging from 0.18 to 0.5. Therefore, the gas adsorption and non-Darcy flow effects, which involve gas slippage, Knudsen diffusion, and surface diffusion, are indispensable parameters of the permeability model for shale.

Experimental determination of the viscous flow permeability of porous materials by measuring reflected low frequency acoustic waves

NASA Astrophysics Data System (ADS)

Berbiche, A.; Sadouki, M.; Fellah, Z. E. A.; Ogam, E.; Fellah, M.; Mitri, F. G.; Depollier, C.

2016-01-01

An acoustic reflectivity method is proposed for measuring the permeability or flow resistivity of air-saturated porous materials. In this method, a simplified expression of the reflection coefficient is derived in the Darcy's regime (low frequency range), which does not depend on frequency and porosity. Numerical simulations show that the reflection coefficient of a porous material can be approximated by its simplified expression obtained from its Taylor development to the first order. This approximation is good especially for resistive materials (of low permeability) and for the lower frequencies. The permeability is reconstructed by solving the inverse problem using waves reflected by plastic foam samples, at different frequency bandwidths in the Darcy regime. The proposed method has the advantage of being simple compared to the conventional methods that use experimental reflected data, and is complementary to the transmissivity method, which is more adapted to low resistive materials (high permeability).

Permeability and permeability anisotropy in Crab Orchard sandstone: Experimental insights into spatio-temporal effects

NASA Astrophysics Data System (ADS)

Gehne, Stephan; Benson, Philip M.

2017-08-01

Permeability in tight crustal rocks is primarily controlled by the connected porosity, shape and orientation of microcracks, the preferred orientation of cross-bedding, and sedimentary features such as layering. This leads to a significant permeability anisotropy. Less well studied, however, are the effects of time and stress recovery on the evolution of the permeability hysteresis which is becoming increasingly important in areas ranging from fluid migration in ore-forming processes to enhanced resource extraction. Here, we report new data simulating spatio-temporal permeability changes induced using effective pressure, simulating burial depth, on a tight sandstone (Crab Orchard). We find an initially (measured at 5 MPa) anisotropy of 2.5% in P-wave velocity and 180% in permeability anisotropy is significantly affected by the direction of the effective pressure change and cyclicity; anisotropy values decrease to 1% and 10% respectively after 3 cycles to 90 MPa and back. Furthermore, we measure a steadily increasing recovery time (10-20 min) for flow parallel to cross-bedding, and a far slower recovery time (20-50 min) for flow normal to cross-bedding. These data are interpreted via strain anisotropy and accommodation models, similar to the "seasoning" process often used in dynamic reservoir extraction.

Method and apparatus for measuring the gas permeability of a solid sample

DOEpatents

Carstens, D.H.W.

1984-01-27

The disclosure is directed to an apparatus and method for measuring the permeability of a gas in a sample. The gas is allowed to reach a steady flow rate through the sample. A measurable amount of the gas is collected during a given time period and then delivered to a sensitive quadrupole. The quadrupole signal, adjusted for background, is proportional to the amount of gas collected during the time period. The quadrupole can be calibrated with a standard helium leak. The gas can be deuterium and the sample can be polyvinyl alcohol.

Age-related changes in mouse bone permeability.

PubMed

Rodriguez-Florez, Naiara; Oyen, Michelle L; Shefelbine, Sandra J

2014-03-21

The determination of lacunar-canalicular permeability is essential for understanding local fluid flow in bone, which may indicate how bone senses changes in the mechanical environment to regulate mechano-adaptation. The estimates of lacunar-canalicular permeability found in the literature vary by up to eight orders of magnitude, and age-related permeability changes have not been measured in non-osteonal mouse bone. The objective of this study is to use a poroelastic approach based on nanoindentation data to characterize lacunar-canalicular permeability in murine bone as a function of age. Nine wild type C57BL/6 mice of different ages (2, 7 and 12 months) were used. Three tibiae from each age group were embedded in epoxy resin, cut in half and indented in the longitudinal direction in the mid-cortex using two spherical fluid indenter tips (R=238 μm and 500 μm). Results suggest that the lacunar-canalicular intrinsic permeability of mouse bone decreases from 2 to 7 months, with no significant changes from 7 to 12 months. The large indenter tip imposed larger contact sizes and sampled larger ranges of permeabilities, particularly for the old bone. This age-related difference in the distribution was not seen for indents with the smaller radius tip. We conclude that the small tip effectively measured lacunar-canalicular permeability, while larger tip indents were influenced by vascular permeability. Exploring the age-related changes in permeability of bone measured by nanoindentation will lead to a better understanding of the role of fluid flow in mechano-transduction. This understanding may help indicate alterations in bone adaptation and remodeling. Copyright © 2013 Elsevier Ltd. All rights reserved.

Permeability of Two Parachute Fabrics: Measurements, Modeling, and Application

NASA Technical Reports Server (NTRS)

Cruz, Juan R.; O'Farrell, Clara; Hennings, Elsa; Runnells, Paul

2017-01-01

Two parachute fabrics, described by Parachute Industry Specifications PIA-C-7020D Type I and PIA-C-44378D Type I, were tested to obtain their permeabilities in air (i.e., flow-through volume of air per area per time) over the range of differential pressures from 0.146 psf (7 Pa) to 25 psf (1197 Pa). Both fabrics met their specification permeabilities at the standard differential pressure of 0.5 inch of water (2.60 psf, 124 Pa). The permeability results were transformed into an effective porosity for use in calculations related to parachutes. Models were created that related the effective porosity to the unit Reynolds number for each of the fabrics. As an application example, these models were used to calculate the total porosities for two geometrically-equivalent subscale Disk-Gap-Band (DGB) parachutes fabricated from each of the two fabrics, and tested at the same operating conditions in a wind tunnel. Using the calculated total porosities and the results of the wind tunnel tests, the drag coefficient of a geometrically-equivalent full-scale DGB operating on Mars was estimated.

Permeability of Two Parachute Fabrics - Measurements, Modeling, and Application

NASA Technical Reports Server (NTRS)

Cruz, Juan R.; O'Farrell, Clara; Hennings, Elsa; Runnells, Paul

2016-01-01

Two parachute fabrics, described by Parachute Industry Specifications PIA-C-7020D Type I and PIA-C-44378D Type I, were tested to obtain their permeabilities in air (i.e., flow-through volume of air per area per time) over the range of differential pressures from 0.146 psf (7 Pa) to 25 psf (1197 Pa). Both fabrics met their specification permeabilities at the standard differential pressure of 0.5 inch of water (2.60 psf, 124 Pa). The permeability results were transformed into an effective porosity for use in calculations related to parachutes. Models were created that related the effective porosity to the unit Reynolds number for each of the fabrics. As an application example, these models were used to calculate the total porosities for two geometrically-equivalent subscale Disk-Gap-Band (DGB) parachutes fabricated from each of the two fabrics, and tested at the same operating conditions in a wind tunnel. Using the calculated total porosities and the results of the wind tunnel tests, the drag coefficient of a geometrically-equivalent full-scale DGB operating on Mars was estimated.

Stress dependence of permeability of intact and fractured shale cores.

NASA Astrophysics Data System (ADS)

van Noort, Reinier; Yarushina, Viktoriya

2016-04-01

Whether a shale acts as a caprock, source rock, or reservoir, understanding fluid flow through shale is of major importance for understanding fluid flow in geological systems. Because of the low permeability of shale, flow is thought to be largely confined to fractures and similar features. In fracking operations, fractures are induced specifically to allow for hydrocarbon exploration. We have constructed an experimental setup to measure core permeabilities, using constant flow or a transient pulse. In this setup, we have measured the permeability of intact and fractured shale core samples, using either water or supercritical CO2 as the transporting fluid. Our measurements show decreasing permeability with increasing confining pressure, mainly due to time-dependent creep. Furthermore, our measurements show that for a simple splitting fracture, time-dependent creep will also eliminate any significant effect of this fracture on permeability. This effect of confinement on fracture permeability can have important implications regarding the effects of fracturing on shale permeability, and hence for operations depending on that.

Permeability After Impact Testing of Composite Laminates

NASA Technical Reports Server (NTRS)

Nettles, Alan T.

2003-01-01

Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a non-linear fashion for almost all of the specimens tested.

Permeability After Impact Testing of Composite Laminates

NASA Technical Reports Server (NTRS)

Nettles, A.T.; Munafo, Paul (Technical Monitor)

2002-01-01

Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a non-linear fashion for almost all of the specimens tested.

Hydrogeology and geochemistry of low-permeability oil-shales - Case study from HaShfela sub-basin, Israel

NASA Astrophysics Data System (ADS)

Burg, Avihu; Gersman, Ronen

2016-09-01

Low permeability rocks are of great importance given their potential role in protecting underlying aquifers from surface and buried contaminants. Nevertheless, only limited data for these rocks is available. New appraisal wells drilled into the oil shale unit (OSU) of the Mt. Scopus Group in the HaShfela sub-basin, Central Israel, provided a one-time opportunity for detailed study of the hydrogeology and geochemistry of this very low permeability unit. Methods used include: slug tests, electrical logs, televiewer imaging, porosity and permeability measurements on core samples, chemical analyses of the rock column and groundwater analyses. Slug tests yielded primary indication to the low permeability of the OSU despite its high porosity (30-40%). Hydraulic conductivities as low as 10-10-10-12 m/s were calculated, using both the Hvorslev and Cooper-Bredehoeft-Papadopulos decoding methods. These low conductivities were confirmed by direct measurements of permeability in cores, and from calculations based on the Kozeny-Carman approach. Storativity was found to be 1 · 10-6 and specific storage - 3.8 · 10-9 m-1. Nevertheless, the very limited water flow in the OSU is argued to be driven gravitationally. The extremely slow recovery rates as well as the independent recovery of two adjacent wells, despite their initial large head difference of 214 m, indicate that the natural fractures are tight and are impermeable due to the confining stress at depth. Laboratory measured permeability is similar or even higher than the field-measured values, thereby confirming that fractures and bedding planes do not form continuous flow paths. The vertical permeability along the OSU is highly variable, implying hydraulic stratification and extremely low vertical hydraulic conductivity. The high salinity of the groundwater (6300-8000 mgCl/L) within the OSU and its chemical and isotopic compositions are explained by the limited water flow, suggesting long residence time of the water

Experimental Study on Permeability of Concrete

NASA Astrophysics Data System (ADS)

Yang, Honglu; Liu, Rentai; Zheng, Zhuo; Liu, Haojie; Gao, Yan; Liu, Yankai

2018-01-01

To study the influencing factors on permeability of pervious concrete, by adding inorganic organic composite materials obtained experimental results show that different aggregate size, aggregate cement ratio of different, different water cement ratio on the permeability performance. The permeability of the concrete was tested by using the self - made permeable device. The experimental results showed that the permeation coefficient of the experiment was obtained and the factors influencing the permeability of the concrete were compared and analyzed. At the same time, the porosity of pervious concrete was measured, the influence of various variables on porosity was studied, and the influence of various factors on the permeability of voids was found. Finally, through comprehensive analysis of a variety of factors, the optimal water cement ratio is 0.28. At this time, the pervious performance of concrete is optimal.

Extra permeability is required to model dynamic oxygen measurements: evidence for functional recruitment?

PubMed Central

Barrett, Matthew JP; Suresh, Vinod

2013-01-01

Neural activation triggers a rapid, focal increase in blood flow and thus oxygen delivery. Local oxygen consumption also increases, although not to the same extent as oxygen delivery. This ‘uncoupling' enables a number of widely-used functional neuroimaging techniques; however, the physiologic mechanisms that govern oxygen transport under these conditions remain unclear. Here, we explore this dynamic process using a new mathematical model. Motivated by experimental observations and previous modeling, we hypothesized that functional recruitment of capillaries has an important role during neural activation. Using conventional mechanisms alone, the model predictions were inconsistent with in vivo measurements of oxygen partial pressure. However, dynamically increasing net capillary permeability, a simple description of functional recruitment, led to predictions consistent with the data. Increasing permeability in all vessel types had the same effect, but two alternative mechanisms were unable to produce predictions consistent with the data. These results are further evidence that conventional models of oxygen transport are not sufficient to predict dynamic experimental data. The data and modeling suggest that it is necessary to include a mechanism that dynamically increases net vascular permeability. While the model cannot distinguish between the different possibilities, we speculate that functional recruitment could have this effect in vivo. PMID:23673433

Psychrometric Measurement of Leaf Water Potential: Lack of Error Attributable to Leaf Permeability.

PubMed

Barrs, H D

1965-07-02

A report that low permeability could cause gross errors in psychrometric determinations of water potential in leaves has not been confirmed. No measurable error from this source could be detected for either of two types of thermocouple psychrometer tested on four species, each at four levels of water potential. No source of error other than tissue respiration could be demonstrated.

Stainless Steel Permeability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchenauer, Dean A.; Karnesky, Richard A.

An understanding of the behavior of hydrogen isotopes in materials is critical to predicting tritium transport in structural metals (at high pressure), estimating tritium losses during production (fission environment), and predicting in-vessel inventory for future fusion devices (plasma driven permeation). Current models often assume equilibrium diffusivity and solubility for a class of materials (e.g. stainless steels or aluminum alloys), neglecting trapping effects or, at best, considering a single population of trapping sites. Permeation and trapping studies of the particular castings and forgings enable greater confidence and reduced margins in the models. For FY15, we have continued our investigation of themore » role of ferrite in permeation for steels of interest to GTS, through measurements of the duplex steel 2507. We also initiated an investigation of the permeability in work hardened materials, to follow up on earlier observations of unusual permeability in a particular region of 304L forgings. Samples were prepared and characterized for ferrite content and coated with palladium to prevent oxidation. Issues with the poor reproducibility of measurements at low permeability were overcome, although the techniques in use are tedious. Funding through TPBAR and GTS were secured for a research grade quadrupole mass spectrometer (QMS) and replacement turbo pumps, which should improve the fidelity and throughput of measurements in FY16.« less

Compaction and Permeability Reduction of Castlegate Sandstone under Pore Pressure Cycling

NASA Astrophysics Data System (ADS)

Bauer, S. J.

2014-12-01

We investigate time-dependent compaction and permeability changes by cycling pore pressure with application to compressed air energy storage (CAES) in a reservoir. Preliminary experiments capture the impacts of hydrostatic stress, pore water pressure, pore pressure cycling, chemical, and time-dependent considerations near a borehole in a CAES reservoir analog. CAES involves creating an air bubble in a reservoir. The high pressure bubble serves as a mechanical battery to store potential energy. When there is excess grid energy, bubble pressure is increased by air compression, and when there is energy needed on the grid, stored air pressure is released through turbines to generate electricity. The analog conditions considered are depth ~1 km, overburden stress ~20 MPa and a pore pressure ~10MPa. Pore pressure is cycled daily or more frequently between ~10 MPa and 6 MPa, consistent with operations of a CAES facility at this depth and may continue for operational lifetime (25 years). The rock can vary from initially fully-to-partially saturated. Pore pressure cycling changes the effective stress.Jacketed, room temperature tap water-saturated samples of Castlegate Sandstone are hydrostatically confined (20 MPa) and subjected to a pore pressure resulting in an effective pressure of ~10 MPa. Pore pressure is cycled between 6 to 10 MPa. Sample displacement measurements yielded determinations of volumetric strain and from water flow measurements permeability was determined. Experiments ran for two to four weeks, with 2 to 3 pore pressure cycles per day. The Castlegate is a fluvial high porosity (>20%) primarily quartz sandstone, loosely calcite cemented, containing a small amount of clay.Pore pressure cycling induces compaction (~.1%) and permeability decreases (~20%). The results imply that time-dependent compactive processes are operative. The load path, of increasing and decreasing pore pressure, may facilitate local loosening and grain readjustments that results in the

Control of the permeability of fractures in geothermal rocks

NASA Astrophysics Data System (ADS)

Faoro, Igor

This thesis comprises three journal articles that will be submitted for publication (Journal of Geophysical Research-Solid Earth). Their respective titles are: "Undrained through Drained Evolution of Permeability in Dual Permeability Media" by Igor Faoro, Derek Elsworth and Chris Marone, "Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution" by Igor Faoro, Derek Elsworth Chris Marone; "Linking permeability and mechanical damage for basalt from Mt. Etna volcano (Italy)" by Igor Faoro, Sergio Vinciguerra, Chris Marone and Derek Elsworth. Undrained through Drained Evolution of Permeability in Dual Permeability Media: temporary permeability changes of fractured aquifers subject to earthquakes have been observed and recorded worldwide, but their comprehension still remains a complex issue. In this study we report on flow-through fracture experiments on cracked westerly cores that reproduce, at laboratory scale, those (steps like) permeability changes that have been recorded when earthquakes occur. In particular our experiments show that under specific test boundary conditions, rapid increments of pore pressure induce transient variations of flow rate of the fracture whose peak magnitudes decrease as the variations of the effective stresses increase. We identify that the observed hydraulic behavior of the fracture is due to two principal mechanisms of origin; respectively mechanical (shortening of core) and poro-elastic (radial diffusion of the pore fluid into the matrix of the sample) whose interaction cause respectively an instantaneous opening and then a progressive closure of the fracture. Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution: we report the results of radial flow-through experiments conducted on heated samples of Westerly granite. These experiments are performed to examine the influence of thermally and mechanically activated

Membrane stress increases cation permeability in red cells.

PubMed

Johnson, R M

1994-11-01

The human red cell is known to increase its cation permeability when deformed by mechanical forces. Light-scattering measurements were used to quantitate the cell deformation, as ellipticity under shear. Permeability to sodium and potassium was not proportional to the cell deformation. An ellipticity of 0.75 was required to increase the permeability of the membrane to cations, and flux thereafter increased rapidly as the limits of cell extension were reached. Induction of membrane curvature by chemical agents also did not increase cation permeability. These results indicate that membrane deformation per se does not increase permeability, and that membrane tension is the effector for increased cation permeability. This may be relevant to some cation permeabilities observed by patch clamping.

Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study

NASA Astrophysics Data System (ADS)

Farough, A.; Moore, D. E.; Lockner, D. A.; Lowell, R. P.

2016-01-01

We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic conditions. A pore pressure difference of up to 2 MPa was imposed across the ends of the sample. Fracture permeability decreased by 1-2 orders of magnitude during the 200-330 h experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferro-magnesian minerals. By comparing the difference between fracture permeability and matrix permeability measured on intact samples of the same rock types, we concluded that the contribution of the low matrix permeability to flow is negligible and essentially all of the flow is focused in the tensile fracture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems can be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of tectonic and crystallization-induced stresses is required to maintain fluid circulation.

Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study

USGS Publications Warehouse

Farough, Aida; Moore, Diane E.; Lockner, David A.; Lowell, R.P.

2016-01-01

We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic conditions. A pore pressure difference of up to 2 MPa was imposed across the ends of the sample. Fracture permeability decreased by 1–2 orders of magnitude during the 200–330 h experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferro-magnesian minerals. By comparing the difference between fracture permeability and matrix permeability measured on intact samples of the same rock types, we concluded that the contribution of the low matrix permeability to flow is negligible and essentially all of the flow is focused in the tensile fracture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems can be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of tectonic and crystallization-induced stresses is required to maintain fluid circulation.

Study on Surface Permeability of Concrete under Immersion

PubMed Central

Liu, Jun; Xing, Feng; Dong, Biqin; Ma, Hongyan; Pan, Dong

2014-01-01

In this paper, concrete specimens are immersed in ultrapure water, to study the evolutions of surface permeability, pore structure and paste microstructure following the prolonging of immersion period. According to the results, after 30-day immersion, the surface permeability of concrete becomes higher as compared with the value before immersion. However, further immersion makes the surface permeability decrease, so that the value measured after 150-day immersion is only half that measured after 30-day immersion. The early increase in surface permeability should be mainly attributed to the leaching of calcium hydroxide, while the later decrease to the refinement of pore structure due to hydration. The two effects work simultaneously and compete throughout the immersion period. The proposed mechanisms get support from microscopic measurements and observations. PMID:28788490

Importance of Low Permeability Natural Gas Reservoirs (released in AEO2010)

EIA Publications

2010-01-01

Production from low-permeability reservoirs, including shale gas and tight gas, has become a major source of domestic natural gas supply. In 2008, low-permeability reservoirs accounted for about 40% of natural gas production and about 35% of natural gas consumption in the United States. Permeability is a measure of the rate at which liquids and gases can move through rock. Low-permeability natural gas reservoirs encompass the shale, sandstone, and carbonate formations whose natural permeability is roughly 0.1 millidarcies or below. (Permeability is measured in darcies.)

Calibration of NMR well logs from carbonate reservoirs with laboratory NMR measurements and μXRCT

DOE PAGES

Mason, Harris E.; Smith, Megan M.; Hao, Yue; ...

2014-12-31

The use of nuclear magnetic resonance (NMR) well log data has the potential to provide in-situ porosity, pore size distributions, and permeability of target carbonate CO₂ storage reservoirs. However, these methods which have been successfully applied to sandstones have yet to be completely validated for carbonate reservoirs. Here, we have taken an approach to validate NMR measurements of carbonate rock cores with independent measurements of permeability and pore surface area to volume (S/V) distributions using differential pressure measurements and micro X-ray computed tomography (μXRCT) imaging methods, respectively. We observe that using standard methods for determining permeability from NMR data incorrectlymore » predicts these values by orders of magnitude. However, we do observe promise that NMR measurements provide reasonable estimates of pore S/V distributions, and with further independent measurements of the carbonate rock properties that universally applicable relationships between NMR measured properties may be developed for in-situ well logging applications of carbonate reservoirs.« less

Calibration of NMR well logs from carbonate reservoirs with laboratory NMR measurements and μXRCT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mason, Harris E.; Smith, Megan M.; Hao, Yue

The use of nuclear magnetic resonance (NMR) well log data has the potential to provide in-situ porosity, pore size distributions, and permeability of target carbonate CO₂ storage reservoirs. However, these methods which have been successfully applied to sandstones have yet to be completely validated for carbonate reservoirs. Here, we have taken an approach to validate NMR measurements of carbonate rock cores with independent measurements of permeability and pore surface area to volume (S/V) distributions using differential pressure measurements and micro X-ray computed tomography (μXRCT) imaging methods, respectively. We observe that using standard methods for determining permeability from NMR data incorrectlymore » predicts these values by orders of magnitude. However, we do observe promise that NMR measurements provide reasonable estimates of pore S/V distributions, and with further independent measurements of the carbonate rock properties that universally applicable relationships between NMR measured properties may be developed for in-situ well logging applications of carbonate reservoirs.« less

Permeability and porosity of hydrate-bearing sediments in the northern Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daigle, Hugh; Cook, Ann; Malinverno, Alberto

Hydrate-bearing sands are being actively explored because they contain the highest concentrations of hydrate and are the most economically recoverable hydrate resource. However, relatively little is known about the mechanisms or timescales of hydrate formation, which are related to methane supply, fluid flux, and host sediment properties such as permeability. We used logging-while-drilling data from locations in the northern Gulf of Mexico to develop an effective medium theory-based model for predicting permeability based on clay-sized sediment fraction. The model considers permeability varying between sand and clay endpoint permeabilities that are defined from laboratory data. We verified the model using permeabilitymore » measurements on core samples from three boreholes, and then used the model to predict permeability in two wells drilled in Walker Ridge Block 313 during the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II expedition in 2009. We found that the cleanest sands (clay-sized fraction <0.05) had intrinsic (hydrate-free) permeability contrasts of 5-6 orders of magnitude with the surrounding clays, which is sufficient to provide focused hydrate formation due to advection of methane from a deep source or diffusion of microbial methane from nearby clay layers. In sands where the clay-sized fraction exceeds 0.05, the permeability reduces significantly and focused flow is less pronounced. In these cases, diffusion of dissolved microbial methane is most likely the preferred mode of methane supply for hydrate formation. In conclusion, our results provide important constraints on methane supply mechanisms in the Walker Ridge area and have global implications for evaluating rates of methane migration and hydrate formation in hydrate-bearing sands.« less

Permeability and porosity of hydrate-bearing sediments in the northern Gulf of Mexico

DOE PAGES

Daigle, Hugh; Cook, Ann; Malinverno, Alberto

2015-10-14

Hydrate-bearing sands are being actively explored because they contain the highest concentrations of hydrate and are the most economically recoverable hydrate resource. However, relatively little is known about the mechanisms or timescales of hydrate formation, which are related to methane supply, fluid flux, and host sediment properties such as permeability. We used logging-while-drilling data from locations in the northern Gulf of Mexico to develop an effective medium theory-based model for predicting permeability based on clay-sized sediment fraction. The model considers permeability varying between sand and clay endpoint permeabilities that are defined from laboratory data. We verified the model using permeabilitymore » measurements on core samples from three boreholes, and then used the model to predict permeability in two wells drilled in Walker Ridge Block 313 during the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II expedition in 2009. We found that the cleanest sands (clay-sized fraction <0.05) had intrinsic (hydrate-free) permeability contrasts of 5-6 orders of magnitude with the surrounding clays, which is sufficient to provide focused hydrate formation due to advection of methane from a deep source or diffusion of microbial methane from nearby clay layers. In sands where the clay-sized fraction exceeds 0.05, the permeability reduces significantly and focused flow is less pronounced. In these cases, diffusion of dissolved microbial methane is most likely the preferred mode of methane supply for hydrate formation. In conclusion, our results provide important constraints on methane supply mechanisms in the Walker Ridge area and have global implications for evaluating rates of methane migration and hydrate formation in hydrate-bearing sands.« less

Surfactant enhanced recovery of tetrachloroethylene from a porous medium containing low permeability lenses. 2. Numerical simulation.

PubMed

Rathfelder, K M; Abriola, L M; Taylor, T P; Pennell, K D

2001-04-01

A numerical model of surfactant enhanced solubilization was developed and applied to the simulation of nonaqueous phase liquid recovery in two-dimensional heterogeneous laboratory sand tank systems. Model parameters were derived from independent, small-scale, batch and column experiments. These parameters included viscosity, density, solubilization capacity, surfactant sorption, interfacial tension, permeability, capillary retention functions, and interphase mass transfer correlations. Model predictive capability was assessed for the evaluation of the micellar solubilization of tetrachloroethylene (PCE) in the two-dimensional systems. Predicted effluent concentrations and mass recovery agreed reasonably well with measured values. Accurate prediction of enhanced solubilization behavior in the sand tanks was found to require the incorporation of pore-scale, system-dependent, interphase mass transfer limitations, including an explicit representation of specific interfacial contact area. Predicted effluent concentrations and mass recovery were also found to depend strongly upon the initial NAPL entrapment configuration. Numerical results collectively indicate that enhanced solubilization processes in heterogeneous, laboratory sand tank systems can be successfully simulated using independently measured soil parameters and column-measured mass transfer coefficients, provided that permeability and NAPL distributions are accurately known. This implies that the accuracy of model predictions at the field scale will be constrained by our ability to quantify soil heterogeneity and NAPL distribution.

Cell volume and plasma membrane osmotic water permeability in epithelial cell layers measured by interferometry.

PubMed Central

Farinas, J; Verkman, A S

1996-01-01

The development of strategies to measure plasma membrane osmotic water permeability (Pf) in epithelial cells has been motivated by the identification of a family of molecular water channels. A general approach utilizing interferometry to measure cell shape and volume was developed and applied to measure Pf in cell layers. The method is based on the cell volume dependence of optical path length (OPL) for a light beam passing through the cell. The small changes in OPL were measured by interferometry. A mathematical model was developed to relate the interference signal to cell volume changes for cells of arbitrary shape and size. To validate the model, a Mach-Zehnder interference microscope was used to image OPL in an Madin Darby Canine Kidney (MDCK) cell layer and to reconstruct the three-dimensional cell shape (OPL resolution < lambda/25). As predicted by the model, a doubling of cell volume resulted in a change in OPL that was proportional to the difference in refractive indices between water and the extracellular medium. The time course of relative cell volume in response to an osmotic gradient was computed from serial interference images. To measure cell volume without microscopy and image analysis, a Mach-Zehnder interferometer was constructed in which one of two interfering laser beams passed through a flow chamber containing the cell layer. The interference signal in response to an osmotic gradient was analyzed to quantify the time course of relative cell volume. The calculated MDCK cell plasma membrane Pf of 6.1 x 10(-4) cm/s at 24 degrees C agreed with that obtained by interference microscopy and by a total internal reflection fluorescence method. Interferometry was also applied to measure the apical plasma membrane water permeability of intact toad urinary bladder; Pf increased fivefold after forskolin stimulation to 0.04 cm/s at 23 degrees C. These results establish and validate the application of interferometry to quantify cell volume and osmotic water

Cell volume and plasma membrane osmotic water permeability in epithelial cell layers measured by interferometry.

PubMed

Farinas, J; Verkman, A S

1996-12-01

The development of strategies to measure plasma membrane osmotic water permeability (Pf) in epithelial cells has been motivated by the identification of a family of molecular water channels. A general approach utilizing interferometry to measure cell shape and volume was developed and applied to measure Pf in cell layers. The method is based on the cell volume dependence of optical path length (OPL) for a light beam passing through the cell. The small changes in OPL were measured by interferometry. A mathematical model was developed to relate the interference signal to cell volume changes for cells of arbitrary shape and size. To validate the model, a Mach-Zehnder interference microscope was used to image OPL in an Madin Darby Canine Kidney (MDCK) cell layer and to reconstruct the three-dimensional cell shape (OPL resolution < lambda/25). As predicted by the model, a doubling of cell volume resulted in a change in OPL that was proportional to the difference in refractive indices between water and the extracellular medium. The time course of relative cell volume in response to an osmotic gradient was computed from serial interference images. To measure cell volume without microscopy and image analysis, a Mach-Zehnder interferometer was constructed in which one of two interfering laser beams passed through a flow chamber containing the cell layer. The interference signal in response to an osmotic gradient was analyzed to quantify the time course of relative cell volume. The calculated MDCK cell plasma membrane Pf of 6.1 x 10(-4) cm/s at 24 degrees C agreed with that obtained by interference microscopy and by a total internal reflection fluorescence method. Interferometry was also applied to measure the apical plasma membrane water permeability of intact toad urinary bladder; Pf increased fivefold after forskolin stimulation to 0.04 cm/s at 23 degrees C. These results establish and validate the application of interferometry to quantify cell volume and osmotic water

A system to measure minute hydraulic permeability of nanometer scale devices in a non-destructive manner

NASA Astrophysics Data System (ADS)

Smith, Ross A.; Fleischman, Aaron J.; Fissell, William H.; Zorman, Christian A.; Roy, Shuvo

2011-04-01

We report an automated system for measuring the hydraulic permeability of nanoporous membranes in a tangential-flow configuration. The system was designed and built specifically for micromachined silicon nanoporous membranes (SNM) with monodisperse slit-shaped pores. These novel membranes are under development for water filtration, artificial organ and drug delivery applications. The filtration cell permits non-destructive testing of the membrane over many remove-modify-replace testing cycles, allowing for direct experiments into the effects of surface modifications on such membranes. The experimental apparatus was validated using microfluidic tubing with circular cross sections that provided similar fluidic resistances to SNM. Further validation was performed with SNM chips for which the pore dimensions were known from scanning electron microscopy measurements. The system was then used to measure the hydraulic permeability of nanoporous membranes before and after surface modification. The system yields measurements with low variance and excellent agreement with predicted values, providing a platform for determining pore sizes in micro/nanofluidic systems with tight pore size distributions to a higher degree of precision than can be achieved with traditional techniques.

Air permeability and trapped-air content in two soils

USGS Publications Warehouse

Stonestrom, David A.; Rubin, Jacob

1989-01-01

To improve understanding of hysteretic air permeability relations, a need exists for data on the water content dependence of air permeability, matric pressure, and air trapping (especially for wetting-drying cycles). To obtain these data, a special instrument was designed. The instrument is a combination of a gas permeameter (for air permeability determination), a suction plate apparatus (for retentivity curve determination), and an air pycnometer (for trapped-air-volume determination). This design allowed values of air permeability, matric pressure, and air trapping to be codetermined, i.e., determined at the same values of water content using the same sample and the same inflow-outflow boundaries. Such data were obtained for two nonswelling soils. The validity of the air permeability determinations was repeatedly confirmed by rigorous tests of Darcy's law. During initial drying from complete water saturation, supplementary measurements were made to assess the magnitude of gas slip. The extended Darcy equation accurately described the measured flux gradient relations for each condition of absolute gas pressure tested. Air permeability functions exhibited zero-permeability regions at high water contents as well as an abruptly appearing hysteresis at low water contents. Measurements in the zero-permeability regions revealed that the total amount of air in general exceeded the amount of trapped air. This indicates that the medium' s air space is partitioned into three measurable domains: through-flowing air, locally accessible air (i.e., air accessible from only one flow boundary), and trapped air. During repeated wetting and drying, the disappearance and reappearance of air permeability coincided closely with the reappearance and disappearance, respectively, of trapped air. The observed relation between critical features of the air permeability functions and those of the air-trapping functions suggest that water-based blockages play a significant role in the

Strength and Numerical Analysis in the Design of Permeable Reactive Barriers

NASA Astrophysics Data System (ADS)

Pawluk, Katarzyna; Wrzesiński, Grzegorz; Lendo-Siwicka, Marzena

2017-10-01

Permeable reactive barriers are one of the most important in situ technologies in groundwater remediation. Most of the installed PRBs have tended to use singular reactive media, but there is an increasing number of applications using combined or sequenced media to treat mixtures of contaminants within a groundwater plume. The concept of a multi-layered permeable reactive barrier (MPRB) to prevent and protect groundwater along traffic routes, especially in ecologically and naturally valuable areas, was developed following several field and laboratory investigations conducted in the Department of Geotechnical Engineering of the Warsaw University of Life Sciences. In accordance with the guidelines of the Interstate Technology & Regulatory Council for the selection of reactive materials, numerous laboratory and field investigations should be performed to determine the environmental conditions, type and concentrations of the contaminants, and the physical-chemical and permeability properties of the reactive materials. However, the deformation and strength properties of the reactive materials should be also considered in the design and evaluation of the safety conditions. In this paper, strength and deformation properties of silica spongolite, zeolite, and activated carbon were investigated using direct shear and oedometer tests. The laboratory test results were used in numerical calculations with the application of the finite element method. The aim of this study was to define the impact of the installation stages of a multi-layered permeable reactive barrier on the stability of a road embankment. Numerical analysis may prevent, reduce or eliminate the risk in the case of a breakdown during the construction or/and exploitation of a PRB.

Step Permeability on the Pt(111) Surface

NASA Astrophysics Data System (ADS)

Altman, Michael

2005-03-01

Surface morphology will be affected, or even dictated, by kinetic limitations that may be present during growth. Asymmetric step attachment is recognized to be an important and possibly common cause of morphological growth instabilities. However, the impact of this kinetic limitation on growth morphology may be hindered by other factors such as the rate limiting step and step permeability. This strongly motivates experimental measurements of these quantities in real systems. Using low energy electron microscopy, we have measured step flow velocities in growth on the Pt(111) surface. The dependence of step velocity upon adjacent terrace width clearly shows evidence of asymmetric step attachment and step permeability. Step velocity is modeled by solving the diffusion equation simultaneously on several adjacent terraces subject to boundary conditions at intervening steps that include asymmetric step attachment and step permeability. This analysis allows a quantitative evaluation of step permeability and the kinetic length, which characterizes the rate limiting step continuously between diffusion and attachment-detachment limited regimes. This work provides information that is greatly needed to set physical bounds on the parameters that are used in theoretical treatments of growth. The observation that steps are permeable even on a simple metal surface should also stimulate more experimental measurements and theoretical treatments of this effect.

Crustal permeability: Introduction to the special issue

USGS Publications Warehouse

Ingebritsen, Steven E.; Gleeson, Tom

2015-01-01

The topic of crustal permeability is of broad interest in light of the controlling effect of permeability on diverse geologic processes and also timely in light of the practical challenges associated with emerging technologies such as hydraulic fracturing for oil and gas production (‘fracking’), enhanced geothermal systems, and geologic carbon sequestration. This special issue of Geofluids is also motivated by the historical dichotomy between the hydrogeologic concept of permeability as a static material property that exerts control on fluid flow and the perspective of economic geologists, geophysicists, and crustal petrologists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. Issues associated with fracking, enhanced geothermal systems, and geologic carbon sequestration have already begun to promote a constructive dialog between the static and dynamic views of permeability, and here we have made a conscious effort to include both viewpoints. This special issue also focuses on the quantification of permeability, encompassing both direct measurement of permeability in the uppermost crust and inferential permeability estimates, mainly for the deeper crust.

Permeability evolution of shale during spontaneous imbibition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, N.; Karpyn, Z. T.; Liu, S.

Shales have small pore and throat sizes ranging from nano to micron scales, low porosity and limited permeability. The poor permeability and complex pore connectivity of shales pose technical challenges to (a) understanding flow and transport mechanisms in such systems and, (b) in predicting permeability changes under dynamic saturation conditions. This paper presents quantitative experimental evidence of the migration of water through a generic shale core plug using micro CT imaging. In addition, in-situ measurements of gas permeability were performed during counter-current spontaneous imbibition of water in nano-darcy permeability Marcellus and Haynesville core plugs. It was seen that water blocksmore » severely reduced the effective permeability of the core plugs, leading to losses of up to 99.5% of the initial permeability in experiments lasting 30 days. There was also evidence of clay swelling which further hindered gas flow. When results from this study were compared with similar counter-current gas permeability experiments reported in the literature, the initial (base) permeability of the rock was found to be a key factor in determining the time evolution of effective gas permeability during spontaneous imbibition. With time, a recovery of effective permeability was seen in the higher permeability rocks, while becoming progressively detrimental and irreversible in tighter rocks. Finally, these results suggest that matrix permeability of ultra-tight rocks is susceptible to water damage following hydraulic fracturing stimulation and, while shut-in/soaking time helps clearing-up fractures from resident fluid, its effect on the adjacent matrix permeability could be detrimental.« less

Permeability evolution of shale during spontaneous imbibition

DOE PAGES

Chakraborty, N.; Karpyn, Z. T.; Liu, S.; ...

2017-01-05

Shales have small pore and throat sizes ranging from nano to micron scales, low porosity and limited permeability. The poor permeability and complex pore connectivity of shales pose technical challenges to (a) understanding flow and transport mechanisms in such systems and, (b) in predicting permeability changes under dynamic saturation conditions. This paper presents quantitative experimental evidence of the migration of water through a generic shale core plug using micro CT imaging. In addition, in-situ measurements of gas permeability were performed during counter-current spontaneous imbibition of water in nano-darcy permeability Marcellus and Haynesville core plugs. It was seen that water blocksmore » severely reduced the effective permeability of the core plugs, leading to losses of up to 99.5% of the initial permeability in experiments lasting 30 days. There was also evidence of clay swelling which further hindered gas flow. When results from this study were compared with similar counter-current gas permeability experiments reported in the literature, the initial (base) permeability of the rock was found to be a key factor in determining the time evolution of effective gas permeability during spontaneous imbibition. With time, a recovery of effective permeability was seen in the higher permeability rocks, while becoming progressively detrimental and irreversible in tighter rocks. Finally, these results suggest that matrix permeability of ultra-tight rocks is susceptible to water damage following hydraulic fracturing stimulation and, while shut-in/soaking time helps clearing-up fractures from resident fluid, its effect on the adjacent matrix permeability could be detrimental.« less

Permeability-Porosity Relationships of Subduction Zone Sediments

NASA Astrophysics Data System (ADS)

Gamage, K.; Screaton, E.; Bekins, B.; Aiello, I.

2008-12-01

Permeability-porosity relationships for sediments from Northern Barbados, Costa Rica, Nankai, and Peru subduction zones were examined based on their sediment type and grain size distribution. Greater correlation was observed between permeability and porosity for siliciclastic sediments, diatom oozes, and nannofossil chalk than for nannofossil oozes. For siliciclastic sediments, grouping of sediments by clay content yields relationships that are generally consistent with results from other marine settings and suggest decreasing permeability for a given porosity as clay content increases. Correction of measured porosities for smectite content generally improves the quality of permeability-porosity relationships. The relationship between permeability and porosity for diatom oozes may be controlled by the amount of clay present in the ooze, causing diatom oozes to behave similarly to siliciclastic sediments. For a given porosity the nannofossil oozes have higher permeability values by 1.5 orders of magnitude than the siliciclastic sediments. However, the use of a permeability-porosity relation may not be appropriate for unconsolidated carbonates such as nannofossil oozes. This study provided insight to the effects of porosity correction for smectite, variations in lithology and grain size in permeability-porosity relationships. However, further progress in delineating controls on permeability will require more careful and better documented permeability tests on characterized samples.

Evaluation of the permeability of agricultural films to various fumigants.

PubMed

Qian, Yaorong; Kamel, Alaa; Stafford, Charles; Nguyen, Thuy; Chism, William J; Dawson, Jeffrey; Smith, Charles W

2011-11-15

A variety of agricultural films are commercially available for managing emissions and enhancing pest control during soil fumigation. These films are manufactured using different materials and processes which can ultimately result in different permeability to fumigants. A systematic laboratory study of the permeability of the agricultural films to nine fumigants was conducted to evaluate the performance of commonly used film products, including polyethylene, metalized, and high-barrier films. The permeability, as expressed by mass transfer coefficient (cm/h), of 27 different films from 13 manufacturers ranged from below 1 × 10(-4) cm/h to above 10 cm/h at 25 °C under ambient relative humidity test conditions. The wide range in permeability of commercially available films demonstrates the need to use films which are appropriate for the fumigation application. The effects of environmental factors, such as temperature and humidity, on the film permeability were also investigated. It was found that high relative humidity could drastically increase the permeability of the high-barrier films. The permeability of some high-barrier films was increased by 2-3 orders of magnitude when the films were tested at high relative humidity. Increasing the temperature from 25 to 40 °C increased the permeability for some high-barrier films up to 10 times more than the permeability at 25 °C, although the effect was minimal for several of these films. Analysis of the distribution of the permeability of the films under ambient humidity conditions to nine fumigants indicated that the 27 films largely followed the material type, although the permeability varied considerably among the films of similar material.

Honeycomb Core Permeability Under Mechanical Loads

NASA Technical Reports Server (NTRS)

Glass, David E.; Raman, V. V.; Venkat, Venki S.; Sankaran, Sankara N.

1997-01-01

A method for characterizing the air permeability of sandwich core materials as a function of applied shear stress was developed. The core material for the test specimens was either Hexcel HRP-3/16-8.0 and or DuPont Korex-1/8-4.5 and was nominally one-half inch thick and six inches square. The facesheets where made of Hercules' AS4/8552 graphite/epoxy (Gr/Ep) composites and were nominally 0.059-in. thick. Cytec's Metalbond 1515-3M epoxy film adhesive was used for co-curing the facesheets to the core. The permeability of the specimens during both static (tension) and dynamic (reversed and non-reversed) shear loads were measured. The permeability was measured as the rate of air flow through the core from a circular 1-in2 area of the core exposed to an air pressure of 10.0 psig. In both the static and dynamic testing, the Korex core experienced sudden increases in core permeability corresponding to a core catastrophic failure, while the URP core experienced a gradual increase in the permeability prior to core failure. The Korex core failed at lower loads than the HRP core both in the transverse and ribbon directions.

Digital Rock Physics Aplications: Visualisation Complex Pore and Porosity-Permeability Estimations of the Porous Sandstone Reservoir

NASA Astrophysics Data System (ADS)

Handoyo; Fatkhan; Del, Fourier

2018-03-01

Reservoir rock containing oil and gas generally has high porosity and permeability. High porosity is expected to accommodate hydrocarbon fluid in large quantities and high permeability is associated with the rock’s ability to let hydrocarbon fluid flow optimally. Porosity and permeability measurement of a rock sample is usually performed in the laboratory. We estimate the porosity and permeability of sandstones digitally by using digital images from μCT-Scan. Advantages of the method are non-destructive and can be applied for small rock pieces also easily to construct the model. The porosity values are calculated by comparing the digital image of the pore volume to the total volume of the sandstones; while the permeability values are calculated using the Lattice Boltzmann calculations utilizing the nature of the law of conservation of mass and conservation of momentum of a particle. To determine variations of the porosity and permeability, the main sandstone samples with a dimension of 300 × 300 × 300 pixels are made into eight sub-cubes with a size of 150 × 150 × 150 pixels. Results of digital image modeling fluid flow velocity are visualized as normal velocity (streamline). Variations in value sandstone porosity vary between 0.30 to 0.38 and permeability variations in the range of 4000 mD to 6200 mD. The results of calculations show that the sandstone sample in this research is highly porous and permeable. The method combined with rock physics can be powerful tools for determining rock properties from small rock fragments.

Fracture-permeability behavior of shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carey, J. William; Lei, Zhou; Rougier, Esteban

The fracture-permeability behavior of Utica shale, an important play for shale gas and oil, was investigated using a triaxial coreflood device and X-ray tomography in combination with finite-discrete element modeling (FDEM). Fractures generated in both compression and in a direct-shear configuration allowed permeability to be measured across the faces of cylindrical core. Shale with bedding planes perpendicular to direct-shear loading developed complex fracture networks and peak permeability of 30 mD that fell to 5 mD under hydrostatic conditions. Shale with bedding planes parallel to shear loading developed simple fractures with peak permeability as high as 900 mD. In addition tomore » the large anisotropy in fracture permeability, the amount of deformation required to initiate fractures was greater for perpendicular layering (about 1% versus 0.4%), and in both cases activation of existing fractures are more likely sources of permeability in shale gas plays or damaged caprock in CO₂ sequestration because of the significant deformation required to form new fracture networks. FDEM numerical simulations were able to replicate the main features of the fracturing processes while showing the importance of fluid penetration into fractures as well as layering in determining fracture patterns.« less

Fracture-permeability behavior of shale

DOE PAGES

Carey, J. William; Lei, Zhou; Rougier, Esteban; ...

2015-05-08

The fracture-permeability behavior of Utica shale, an important play for shale gas and oil, was investigated using a triaxial coreflood device and X-ray tomography in combination with finite-discrete element modeling (FDEM). Fractures generated in both compression and in a direct-shear configuration allowed permeability to be measured across the faces of cylindrical core. Shale with bedding planes perpendicular to direct-shear loading developed complex fracture networks and peak permeability of 30 mD that fell to 5 mD under hydrostatic conditions. Shale with bedding planes parallel to shear loading developed simple fractures with peak permeability as high as 900 mD. In addition tomore » the large anisotropy in fracture permeability, the amount of deformation required to initiate fractures was greater for perpendicular layering (about 1% versus 0.4%), and in both cases activation of existing fractures are more likely sources of permeability in shale gas plays or damaged caprock in CO₂ sequestration because of the significant deformation required to form new fracture networks. FDEM numerical simulations were able to replicate the main features of the fracturing processes while showing the importance of fluid penetration into fractures as well as layering in determining fracture patterns.« less

Permeability During Magma Expansion and Compaction

NASA Astrophysics Data System (ADS)

Gonnermann, Helge. M.; Giachetti, Thomas; Fliedner, Céline; Nguyen, Chinh T.; Houghton, Bruce F.; Crozier, Joshua A.; Carey, Rebecca J.

2017-12-01

Plinian lapilli from the 1060 Common Era Glass Mountain rhyolitic eruption of Medicine Lake Volcano, California, were collected and analyzed for vesicularity and permeability. A subset of the samples were deformed at a temperature of 975°, under shear and normal stress, and postdeformation porosities and permeabilities were measured. Almost all undeformed samples fall within a narrow range of vesicularity (0.7-0.9), encompassing permeabilities between approximately 10-15 m2 and 10-10 m2. A percolation threshold of approximately 0.7 is required to fit the data by a power law, whereas a percolation threshold of approximately 0.5 is estimated by fitting connected and total vesicularity using percolation modeling. The Glass Mountain samples completely overlap with a range of explosively erupted silicic samples, and it remains unclear whether the erupting magmas became permeable at porosities of approximately 0.7 or at lower values. Sample deformation resulted in compaction and vesicle connectivity either increased or decreased. At small strains permeability of some samples increased, but at higher strains permeability decreased. Samples remain permeable down to vesicularities of less than 0.2, consistent with a potential hysteresis in permeability-porosity between expansion (vesiculation) and compaction (outgassing). We attribute this to retention of vesicle interconnectivity, albeit at reduced vesicle size, as well as bubble coalescence during shear deformation. We provide an equation that approximates the change in permeability during compaction. Based on a comparison with data from effusively erupted silicic samples, we propose that this equation can be used to model the change in permeability during compaction of effusively erupting magmas.

Permeability-porosity relationships in sedimentary rocks

USGS Publications Warehouse

Nelson, Philip H.

1994-01-01

In many consolidated sandstone and carbonate formations, plots of core data show that the logarithm of permeability (k) is often linearly proportional to porosity (??). The slope, intercept, and degree of scatter of these log(k)-?? trends vary from formation to formation, and these variations are attributed to differences in initial grain size and sorting, diagenetic history, and compaction history. In unconsolidated sands, better sorting systematically increases both permeability and porosity. In sands and sandstones, an increase in gravel and coarse grain size content causes k to increase even while decreasing ??. Diagenetic minerals in the pore space of sandstones, such as cement and some clay types, tend to decrease log(k) proportionately as ?? decreases. Models to predict permeability from porosity and other measurable rock parameters fall into three classes based on either grain, surface area, or pore dimension considerations. (Models that directly incorporate well log measurements but have no particular theoretical underpinnings from a fourth class.) Grain-based models show permeability proportional to the square of grain size times porosity raised to (roughly) the fifth power, with grain sorting as an additional parameter. Surface-area models show permeability proportional to the inverse square of pore surface area times porosity raised to (roughly) the fourth power; measures of surface area include irreducible water saturation and nuclear magnetic resonance. Pore-dimension models show permeability proportional to the square of a pore dimension times porosity raised to a power of (roughly) two and produce curves of constant pore size that transgress the linear data trends on a log(k)-?? plot. The pore dimension is obtained from mercury injection measurements and is interpreted as the pore opening size of some interconnected fraction of the pore system. The linear log(k)-?? data trends cut the curves of constant pore size from the pore-dimension models

Constraining the effects of permeability uncertainty for geologic CO2 sequestration in a basalt reservoir

NASA Astrophysics Data System (ADS)

Jayne, R., Jr.; Pollyea, R.

2016-12-01

Carbon capture and sequestration (CCS) in geologic reservoirs is one strategy for reducing anthropogenic CO2 emissions from large-scale point-source emitters. Recent developments at the CarbFix CCS pilot in Iceland have shown that basalt reservoirs are highly effective for permanent mineral trapping on the basis of CO2-water-rock interactions, which result in the formation of carbonates minerals. In order to advance our understanding of basalt sequestration in large igneous provinces, this research uses numerical simulation to evaluate the feasibility of industrial-scale CO2 injections in the Columbia River Basalt Group (CRBG). Although bulk reservoir properties are well constrained on the basis of field and laboratory testing from the Wallula Basalt Sequestration Pilot Project, there remains significant uncertainty in the spatial distribution of permeability at the scale of individual basalt flows. Geostatistical analysis of hydrologic data from 540 wells illustrates that CRBG reservoirs are reasonably modeled as layered heterogeneous systems on the basis of basalt flow morphology; however, the regional dataset is insufficient to constrain permeability variability at the scale of an individual basalt flow. As a result, permeability distribution for this modeling study is established by centering the lognormal permeability distribution in the regional dataset over the bulk permeability measured at Wallula site, which results in a spatially random permeability distribution within the target reservoir. In order to quantify the effects of this permeability uncertainty, CO2 injections are simulated within 50 equally probable synthetic reservoir domains. Each model domain comprises three-dimensional geometry with 530,000 grid blocks, and fracture-matrix interaction is simulated as interacting continua for the two low permeability layers (flow interiors) bounding the injection zone. Results from this research illustrate that permeability uncertainty at the scale of

Crustal permeability

USGS Publications Warehouse

Gleeson, Tom; Ingebritsen, Steven E.

2016-01-01

Permeability is the primary control on fluid flow in the Earth’s crust and is key to a surprisingly wide range of geological processes, because it controls the advection of heat and solutes and the generation of anomalous pore pressures.  The practical importance of permeability – and the potential for large, dynamic changes in permeability – is highlighted by ongoing issues associated with hydraulic fracturing for hydrocarbon production (“fracking”), enhanced geothermal systems, and geologic carbon sequestration.  Although there are thousands of research papers on crustal permeability, this is the first book-length treatment.  This book bridges the historical dichotomy between the hydrogeologic perspective of permeability as a static material property and the perspective of other Earth scientists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. 

Relative Permeabilities of Plastic Films to Water and Carbon Dioxide

PubMed Central

Woolley, Joseph T.

1967-01-01

The permeabilities of several types of plastic films to water and to carbon dioxide were measured. No material was found to have a carbon dioxide permeability as great as its water permeability. PMID:16656548

Seismic waves increase permeability.

PubMed

Elkhoury, Jean E; Brodsky, Emily E; Agnew, Duncan C

2006-06-29

Earthquakes have been observed to affect hydrological systems in a variety of ways--water well levels can change dramatically, streams can become fuller and spring discharges can increase at the time of earthquakes. Distant earthquakes may even increase the permeability in faults. Most of these hydrological observations can be explained by some form of permeability increase. Here we use the response of water well levels to solid Earth tides to measure permeability over a 20-year period. At the time of each of seven earthquakes in Southern California, we observe transient changes of up to 24 degrees in the phase of the water level response to the dilatational volumetric strain of the semidiurnal tidal components of wells at the Piñon Flat Observatory in Southern California. After the earthquakes, the phase gradually returns to the background value at a rate of less than 0.1 degrees per day. We use a model of axisymmetric flow driven by an imposed head oscillation through a single, laterally extensive, confined, homogeneous and isotropic aquifer to relate the phase response to aquifer properties. We interpret the changes in phase response as due to changes in permeability. At the time of the earthquakes, the permeability at the site increases by a factor as high as three. The permeability increase depends roughly linearly on the amplitude of seismic-wave peak ground velocity in the range of 0.21-2.1 cm s(-1). Such permeability increases are of interest to hydrologists and oil reservoir engineers as they affect fluid flow and might determine long-term evolution of hydrological and oil-bearing systems. They may also be interesting to seismologists, as the resulting pore pressure changes can affect earthquakes by changing normal stresses on faults.

Porosity and Permeability Evolution Accompanying Hot fluid Injection into Diatomite, SUPRI TR-123

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diabira, I.; Castanier, L.M.; Kovscek, A.R.

2001-04-19

An experimental study of silica dissolution was performed to probe the evolution of permeability and porosity in siliceous diatomite during hot fluid injection such as water or steam flooding. Two competing mechanisms were identified. Silica solubility in water at elevated temperature causes rock dissolution thereby increasing permeability; however, the rock is mechanically weak leading to compressing of the solid matrix during injection. Permeability and porosity can decrease at the onset of fluid flow. A laboratory flow apparatus was designed and built to examine these processes in diatomite core samples.

Water and solute permeability of rat lung caveolae: high permeabilities explained by acyl chain unsaturation.

PubMed

Hill, Warren G; Almasri, Eyad; Ruiz, W Giovanni; Apodaca, Gerard; Zeidel, Mark L

2005-07-01

Caveolae are invaginated membrane structures with high levels of cholesterol, sphingomyelin, and caveolin protein that are predicted to exist as liquid-ordered domains with low water permeability. We isolated a caveolae-enriched membrane fraction without detergents from rat lung and characterized its permeability properties to nonelectrolytes and protons. Membrane permeability to water was 2.85 +/- 0.41 x 10(-3) cm/s, a value 5-10 times higher than expected based on comparisons with other cholesterol and sphingolipid-enriched membranes. Permeabilities to urea, ammonia, and protons were measured and found to be moderately high for urea and ammonia at 8.85 +/- 2.40 x 10(-7)and 6.84 +/- 1.03 x 10(-2) respectively and high for protons at 8.84 +/- 3.06 x 10(-2) cm/s. To examine whether caveolin or other integral membrane proteins were responsible for high permeabilities, liposomes designed to mimic the lipids of the inner and outer leaflets of the caveolar membrane were made. Osmotic water permeability to both liposome compositions were determined and a combined inner/outer leaflet water permeability was calculated and found to be close to that of native caveolae at 1.58 +/- 1.1 x 10(-3) cm/s. In caveolae, activation energy for water flux was high (19.4 kcal/mol) and water permeability was not inhibited by HgCl2; however, aquaporin 1 was detectable by immunoblotting. Immunostaining of rat lung with AQP1 and caveolin antisera revealed very low levels of colocalization. We conclude that aquaporin water channels do not contribute significantly to the observed water flux and that caveolae have relatively high water and solute permeabilities due to the high degree of unsaturation in their fatty acyl chains.

Permeability hysterisis of limestone during isotropic compression.

PubMed

Selvadurai, A P S; Głowacki, A

2008-01-01

The evolution of permeability hysterisis in Indiana Limestone during application of isotropic confining pressures up to 60 MPa was measured by conducting one-dimensional constant flow rate tests. These tests were carried out either during monotonic application of the confining pressure or during loading-partial unloading cycles. Irreversible permeability changes occurred during both monotonic and repeated incremental compression of the limestone. Mathematical relationships are developed for describing the evolution of path-dependent permeability during isotropic compression.

Microfluidic passive permeability assay using nanoliter droplet interface lipid bilayers.

PubMed

Nisisako, Takasi; Portonovo, Shiva A; Schmidt, Jacob J

2013-11-21

Membrane permeability assays play an important role in assessing drug transport activities across biological membranes. However, in conventional parallel artificial membrane permeability assays (PAMPA), the membrane model used is dissimilar to biological membranes physically and chemically. Here, we describe a microfluidic passive permeability assay using droplet interface bilayers (DIBs). In a microfluidic network, nanoliter-sized donor and acceptor aqueous droplets are alternately formed in cross-flowing oil containing phospholipids. Subsequently, selective removal of oil through hydrophobic pseudo-porous sidewalls induces the contact of the lipid monolayers, creating arrayed planar DIBs between the donor and acceptor droplets. Permeation of fluorescein from the donor to the acceptor droplets was fluorometrically measured. From the measured data and a simple diffusion model we calculated the effective permeabilities of 5.1 × 10(-6) cm s(-1), 60.0 × 10(-6) cm s(-1), and 87.6 × 10(-6) cm s(-1) with donor droplets at pH values of 7.5, 6.4 and 5.4, respectively. The intrinsic permeabilities of specific monoanionic and neutral fluorescein species were obtained similarly. We also measured the permeation of caffeine in 10 min using UV microspectroscopy, obtaining a permeability of 20.8 × 10(-6) cm s(-1). With the small solution volumes, short measurement time, and ability to measure a wide range of compounds, this device has considerable potential as a platform for high-throughput drug permeability assays.

Caprock integrity susceptibility to permeable fracture creation

DOE PAGES

Frash, Luke; Carey, James William; Ickes, Timothy Lee; ...

2017-07-14

Caprock leakage is of crucial concern for environmentally and economically sustainable development of carbon dioxide sequestration and utilization operations. One potential leakage pathway is through fractures or faults that penetrate the caprock. In this study, we investigate the permeability induced by fracturing initially intact Marcellus shale outcrop specimens at stressed conditions using a triaxial direct-shear method. Measurements of induced permeability, fracture geometry, displacement, and applied stresses were all obtained at stressed conditions to investigate the coupled processes of fracturing and fluid flow as may occur in the subsurface. Fracture geometry was directly observed at stressed conditions using X-ray radiography video.more » Numerical simulation was performed to evaluate the stress distribution developed in the experiments. Our experiments show that permeability induced by fracturing is strongly dependent on the stresses at which the fractures are created, the magnitude of shearing displacement, and the duration of flow. The strongest permeability contrast was observed when comparing specimens fractured at low stress to others fractured at higher stress. Measureable fracture permeability decreased by up to 7 orders of magnitude over a corresponding triaxial confining stress range of 3.5 MPa to 30 MPa. These results show that increasing stress, depth, and time are all significant permeability inhibitors that may limit potential leakage through fractured caprock.« less

Caprock integrity susceptibility to permeable fracture creation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frash, Luke; Carey, James William; Ickes, Timothy Lee

Caprock leakage is of crucial concern for environmentally and economically sustainable development of carbon dioxide sequestration and utilization operations. One potential leakage pathway is through fractures or faults that penetrate the caprock. In this study, we investigate the permeability induced by fracturing initially intact Marcellus shale outcrop specimens at stressed conditions using a triaxial direct-shear method. Measurements of induced permeability, fracture geometry, displacement, and applied stresses were all obtained at stressed conditions to investigate the coupled processes of fracturing and fluid flow as may occur in the subsurface. Fracture geometry was directly observed at stressed conditions using X-ray radiography video.more » Numerical simulation was performed to evaluate the stress distribution developed in the experiments. Our experiments show that permeability induced by fracturing is strongly dependent on the stresses at which the fractures are created, the magnitude of shearing displacement, and the duration of flow. The strongest permeability contrast was observed when comparing specimens fractured at low stress to others fractured at higher stress. Measureable fracture permeability decreased by up to 7 orders of magnitude over a corresponding triaxial confining stress range of 3.5 MPa to 30 MPa. These results show that increasing stress, depth, and time are all significant permeability inhibitors that may limit potential leakage through fractured caprock.« less

Surface Infiltration Rates of Permeable Surfaces: Six Month ...

EPA Pesticide Factsheets

At the end of October 2009, EPA opened a parking lot on the Edison Environmental Center that included three parking rows of permeable pavement. The construction was a cooperative effort among EPA’s Office of Administration and Resources Management, National Risk Management Research Laboratory, and the facility owner, Region 2. The lot serves as an active parking area for facility staff and visitors and also as a research platform. Key unknowns in the application of green infrastructure include the long term performance and the maintenance requirements. The perceived uncertainty in these is a barrier to widespread adoption of the installation of permeable surfaces for stormwater management. EPA recognizes the need for credible long-term performance maintenance data and has begun a long-term monitoring effort on this installation. This document outlines the methods and results of the surface infiltration monitoring of the permeable parking surfaces during the first six months of operation. To inform the public.

Microfluidic-based Broadband Measurements of Fluid Permittivity and Permeability to 100 GHz

NASA Astrophysics Data System (ADS)

Little, Charles A. E.

This dissertation concerns the development of unique microfluidic microwave devices and associated microwave calibrations to quantitatively extract the broadband permittivity and permeability of fluids between 100 kHz and 110 GHz. The devices presented here consist of SU-8- and PDMS-based microfluidic channels integrated lithographically with coplanar waveguides (CPWs), measured via an external vector network analyzer (VNA). By applying our hybrid set of microwave calibrations to the raw data we extract distributed circuit parameters, representative of the electromagnetic response of the microfluidic channel. We then correlate these parameters to the permittivity and permeability of the fluid within the channels. We are primarily focused on developing devices, calibrations, and analyses to characterize various chemical and biological systems. The small fluid volumes and overall scale of our devices lends the technique to point-of-care blood and cell analysis, as well as to the analysis of high-value chemicals. Broadband microwave microfluidics is sensitive to three primary categories of phenomena: Ionic, dipolar, and magnetic resonances. All three can occur in complex fluids such as blood, proteins and particle suspensions. In order to make quantitative measurements, we need to be able to model and separate all three types of responses. Here we first measure saline solutions (NaCl and water) as an ideal system to better understanding both the ionic and dipolar response. Specifically, we are targeting the electrical double-layer (EDL) response, an ionic effect, which dominates over the intrinsic fluid response at lower frequencies. We have found that the EDL response for saline obeys a strict Debye-type relaxation model, the frequency response of which is dependent solely on the conductivity of the solution. To develop a better understanding of the magnetic response, we first measure magnetic nanoparticles; showing it is possible to detect the magnetic resonances of

Compaction and gas loss in welded pyroclastic deposits as revealed by porosity, permeability, and electrical conductivity measurements of the Shevlin Park Tuff

USGS Publications Warehouse

Wright, Heather M.; Cashman, Katharine V.

2014-01-01

Pyroclastic flows produced by large volcanic eruptions commonly densify after emplacement. Processes of gas escape, compaction, and welding in pyroclastic-flow deposits are controlled by the physical and thermal properties of constituent material. Through measurements of matrix porosity, permeability, and electrical conductivity, we provide a framework for understanding the evolution of pore structure during these processes. Using data from the Shevlin Park Tuff in central Oregon, United States, and from the literature, we find that over a porosity range of 0%–70%, matrix permeability varies by almost 10 orders of magnitude (from 10–20 to 10–11 m2), with over three orders of magnitude variation at any given porosity. Part of the variation at a given porosity is due to permeability anisotropy, where oriented core samples indicate higher permeabilities parallel to foliation (horizontally) than perpendicular to foliation (vertically). This suggests that pore space is flattened during compaction, creating anisotropic crack-like networks, a geometry that is supported by electrical conductivity measurements. We find that the power law equation: k1 = 1.3 × 10–21 × ϕ5.2 provides the best approximation of dominant horizontal gas loss, where k1 = permeability, and ϕ = porosity. Application of Kozeny-Carman fluid-flow approximations suggests that permeability in the Shevlin Park Tuff is controlled by crack- or disk-like pore apertures with minimum widths of 0.3 and 7.5 μm. We find that matrix permeability limits compaction over short times, but deformation is then controlled by competition among cooling, compaction, water resorption, and permeable gas escape. These competing processes control the potential for development of overpressure (and secondary explosions) and the degree of welding in the deposit, processes that are applicable to viscous densification of volcanic deposits in general. Further, the general relationships among porosity, permeability, and

A multidisciplinary approach to quantify the permeability of the Whakaari/White Island volcanic hydrothermal system (Taupo Volcanic Zone, New Zealand)

NASA Astrophysics Data System (ADS)

Heap, Michael J.; Kennedy, Ben M.; Farquharson, Jamie I.; Ashworth, James; Mayer, Klaus; Letham-Brake, Mark; Reuschlé, Thierry; Gilg, H. Albert; Scheu, Bettina; Lavallée, Yan; Siratovich, Paul; Cole, Jim; Jolly, Arthur D.; Baud, Patrick; Dingwell, Donald B.

2017-02-01

Our multidisciplinary study aims to better understand the permeability of active volcanic hydrothermal systems, a vital prerequisite for modelling and understanding their behaviour and evolution. Whakaari/White Island volcano (an active stratovolcano at the north-eastern end of the Taupo Volcanic Zone of New Zealand) hosts a highly reactive hydrothermal system and represents an ideal natural laboratory to undertake such a study. We first gained an appreciation of the different lithologies at Whakaari and (where possible) their lateral and vertical extent through reconnaissance by land, sea, and air. The main crater, filled with tephra deposits, is shielded by a volcanic amphitheatre comprising interbedded lavas, lava breccias, and tuffs. We deployed field techniques to measure the permeability and density/porosity of (1) > 100 hand-sized sample blocks and (2) layered unlithified deposits in eight purpose-dug trenches. Our field measurements were then groundtruthed using traditional laboratory techniques on almost 150 samples. Our measurements highlight that the porosity of the materials at Whakaari varies from ∼ 0.01 to ∼ 0.7 and permeability varies by eight orders of magnitude (from ∼ 10-19 to ∼ 10-11 m2). The wide range in physical and hydraulic properties is the result of the numerous lithologies and their varied microstructures and alteration intensities, as exposed by a combination of macroscopic and microscopic (scanning electron microscopy) observations, quantitative mineralogical studies (X-ray powder diffraction), and mercury porosimetry. An understanding of the spatial distribution of lithology and alteration style/intensity is therefore important to decipher fluid flow within the Whakaari volcanic hydrothermal system. We align our field observations and porosity/permeability measurements to construct a schematic cross section of Whakaari that highlights the salient findings of our study. Taken together, the alteration typical of a volcanic

Dynamic Measurement of Tumor Vascular Permeability and Perfusion using a Hybrid System for Simultaneous Magnetic Resonance and Fluorescence Imaging.

PubMed

Ren, Wuwei; Elmer, Andreas; Buehlmann, David; Augath, Mark-Aurel; Vats, Divya; Ripoll, Jorge; Rudin, Markus

2016-04-01

Assessing tumor vascular features including permeability and perfusion is essential for diagnostic and therapeutic purposes. The aim of this study was to compare fluorescence and magnetic resonance imaging (MRI)-based vascular readouts in subcutaneously implanted tumors in mice by simultaneous dynamic measurement of tracer uptake using a hybrid fluorescence molecular tomography (FMT)/MRI system. Vascular permeability was measured using a mixture of extravascular imaging agents, GdDOTA and the dye Cy5.5, and perfusion using a mixture of intravascular agents, Endorem and a fluorescent probe (Angiosense). Dynamic fluorescence reflectance imaging (dFRI) was integrated into the hybrid system for high temporal resolution. Excellent correspondence between uptake curves of Cy5.5/GdDOTA and Endorem/Angiosense has been found with correlation coefficients R > 0.98. The two modalities revealed good agreement regarding permeability coefficients and centers-of-gravity of the imaging agent distribution. The FMT/dFRI protocol presented is able to accurately map physiological processes and poses an attractive alternative to MRI for characterizing tumor neoangiogenesis.

Effects of pore pressure and mud filtration on drilling rates in a permeable sandstone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Black, A.D.; DiBona, B.; Sandstrom, J.

1983-10-01

During laboratory drilling tests in a permeable sandstone, the effects of pore pressure and mud filtration on penetration rates were measured. Four water-base muds were used to drill four saturated sandstone samples. The drilling tests were conducted at constant borehole pressure with different back pressures maintained on the filtrate flowing from the bottom of the sandstone samples. Bit weight was also varied. Filtration rates were measured while drilling and with the bit off bottom and mud circulating. Penetration rates were found to be related to the difference between the filtration rates measured while drilling and circulating. There was no observedmore » correlation between standard API filtration measurements and penetration rate.« less

Effects of pore pressure and mud filtration on drilling rates in a permeable sandstone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Black, A.D.; Dearing, H.L.; DiBona, B.G.

1985-09-01

During laboratory drilling tests in a permeable sandstone, the effects of pore pressure and mud filtration on penetration rates were measured. Four water-based muds were used to drill four saturated sandstone samples. The drilling tests were conducted at constant borehole pressure while different backpressures were maintained on the filtrate flowing from the bottom of the sandstone samples. Bit weight was varied also. Filtration rates were measured while circulating mud during drilling and with the bit off bottom. Penetration rates were found to be related qualitatively to the difference between the filtration rates measured while drilling and circulating. There was nomore » observed correlation between standard API filtration measurements and penetration rate.« less

Gas permeability of ice-templated, unidirectional porous ceramics

NASA Astrophysics Data System (ADS)

Seuba, Jordi; Deville, Sylvain; Guizard, Christian; Stevenson, Adam J.

2016-01-01

We investigate the gas flow behavior of unidirectional porous ceramics processed by ice-templating. The pore volume ranged between 54% and 72% and pore size between 2.9 ?m and 19.1 ?m. The maximum permeability (?? m?) was measured in samples with the highest total pore volume (72%) and pore size (19.1 ?m). However, we demonstrate that it is possible to achieve a similar permeability (?? m?) at 54% pore volume by modification of the pore shape. These results were compared with those reported and measured for isotropic porous materials processed by conventional techniques. In unidirectional porous materials tortuosity (?) is mainly controlled by pore size, unlike in isotropic porous structures where ? is linked to pore volume. Furthermore, we assessed the applicability of Ergun and capillary model in the prediction of permeability and we found that the capillary model accurately describes the gas flow behavior of unidirectional porous materials. Finally, we combined the permeability data obtained here with strength data for these materials to establish links between strength and permeability of ice-templated materials.

Measuring Clogging with Pressure Transducers in Permeable Pavement Strips

EPA Science Inventory

Two issues that have a negative affect on the long term hydrologic performance of permeable pavement systems are surface clogging and clogging at the interface with the underlying soil. Surface clogging limits infiltration capacity and results in bypass if runoff rate exceeds in...

Permeability of the San Andreas Fault Zone at Depth

NASA Astrophysics Data System (ADS)

Rathbun, A. P.; Song, I.; Saffer, D.

2010-12-01

Quantifying fault rock permeability is important toward understanding both the regional hydrologic behavior of fault zones, and poro-elastic processes that affect fault mechanics by mediating effective stress. These include long-term fault strength as well as dynamic processes that may occur during earthquake slip, including thermal pressurization and dilatancy hardening. Despite its importance, measurements of fault zone permeability for relevant natural materials are scarce, owing to the difficulty of coring through active fault zones seismogenic depths. Most existing measurements of fault zone permeability are from altered surface samples or from thinner, lower displacement faults than the SAF. Here, we report on permeability measurements conducted on gouge from the actively creeping Central Deformation Zone (CDZ) of the San Andreas Fault, sampled in the SAFOD borehole at a depth of ~2.7 km (Hole G, Run 4, sections 4,5). The matrix of the gouge in this interval is predominantly composed of particles <10 µm, with ~5 vol% clasts of serpentinite, very fine-grained sandstone, and siltstone. The 2.6 m-thick CDZ represents the main fault trace and hosts ~90% of the active slip on the SAF at this location, as documented by repeated casing deformation surveys. We measured permeability in two different configurations: (1) in a uniaxial pressure cell, in which a sample is placed into a rigid steel ring which imposes a zero lateral strain condition and subjected to axial load, and (2) in a standard triaxial system under isostatic stress conditions. In the uniaxial configuration, we obtained permeabilities at axial effective stresses up to 90 MPa, and in the triaxial system up to 10 MPa. All experiments were conducted on cylindrical subsamples of the SAFOD core 25 mm in diameter, with lengths ranging from 18mm to 40mm, oriented for flow approximately perpendicular to the fault. In uniaxial tests, permeability is determined by running constant rate of strain (CRS) tests up

Effect of permeability enhancers on paracellular permeability of acyclovir.

PubMed

Ates, Muge; Kaynak, Mustafa Sinan; Sahin, Selma

2016-06-01

According to Biopharmaceutics Classification System (BCS), acyclovir is a class III (high solubility, low permeability) compound, and it is transported through paracellular route by passive diffusion. The aim of this study was to investigate the effect of various pharmaceutical excipients on the intestinal permeability of acyclovir. The single-pass in-situ intestinal perfusion (SPIP) method was used to estimate the permeability values of acyclovir and metoprolol across different intestinal segments (jejunum, ileum and colon). Permeability coefficient (Peff ) of acyclovir was determined in the absence and presence of a permeation enhancer such as dimethyl β-cyclodextrin (DM-β-CD), sodium lauryl sulfate (SLS), sodium caprate (Cap-Na) and chitosan chloride. All enhancers increased the permeability of paracellularly transported acyclovir. Although Cap-Na has the highest permeability-enhancing effect in all segments, permeation-enhancing effect of chitosan and SLS was only significant in ileum. On the other hand, DM-β-CD slightly decreased the permeability in all intestinal segments. These findings have potential implication concerning the enhancement of absorption of paracellularly transported compounds with limited oral bioavailability. In the case of acyclovir, Cap-Na either alone or in combination with SLS or chitosan has the potential to improve its absorption and bioavailability and has yet to be explored. © 2016 Royal Pharmaceutical Society.

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

DOE PAGES

Rutqvist, J.

2014-09-19

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutqvist, J.

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Benthic photosynthesis and oxygen consumption in permeable carbonate sediments at Heron Island, Great Barrier Reef, Australia

NASA Astrophysics Data System (ADS)

Rasheed, Mohammed; Wild, Christian; Franke, Ulrich; Huettel, Markus

2004-01-01

In order to investigate benthic photosynthesis and oxygen demand in permeable carbonate sands and the impact of benthic boundary layer flow on sedimentary oxygen consumption, in situ and laboratory chamber experiments were carried out at Heron Island, Great Barrier Reef, Australia. Total photosynthesis, net primary production and respiration were estimated to be 162.9±43.4, 98.0±40.7, and 64.9±15.0 mmol C m -2 d -1, respectively. DIN and DIP fluxes for these sands reached 0.34 and 0.06 mmol m -2 d -1, respectively. Advective pore water exchange had a strong impact on oxygen consumption in the permeable sands. Consumption rates in the chamber with larger pressure gradient (20 rpm, 1.2 Pa between centre and rim) simulating a friction velocity of 0.6 cm s -1 were approximately two-fold higher than in the chambers with slow stirring (10 rpm, 0.2 Pa between centre and rim, friction velocity of 0.3 cm s -1). In the laboratory chamber experiments with stagnant water column, oxygen consumption was eight times lower than in the chamber with fast stirring. Laboratory chamber experiments with Br - tracer revealed solute exchange rates of 2.6, 2.2, 0.7 ml cm -2 d -1 at stirring rates of 20, 10, and 0 rpm, respectively. In a laboratory experiment investigating the effect of sediment permeability on oxygen and DIC fluxes, a three-fold higher permeability resulted in two- to three-fold higher oxygen consumption and DIC release rates. These experiments demonstrate the importance of boundary flow induced flushing of the upper layer of permeable carbonate sediment on oxygen uptake in the coral sands. The high filtration and oxidation rates in the sub-tropical permeable carbonate sediments and the subsequent release of nutrients and DIC reveal the importance of these sands for the recycling of matter in this oligotrophic environment.

Air Permeability of Renovation Plasters Evaluated with Torrent’s Method

NASA Astrophysics Data System (ADS)

Brasse, Krystian; Tracz, Tomasz

2017-10-01

The aim of research was to determine the air permeability of the renovation plasters, using Torrent’s method. The scope of this research included three renovation plaster systems. Each of them was applied on experimental, masonry element and had a different rendering coat. Permeability measurements were performed after 28 days of curing in a natural state. In order to calculate the coefficient of air permeability (kT), the partial data was registered during the measurements. The test results indicate the possibility of determination the coefficient of air permeability kT in relation to the renovation plasters. At the same time results confirm the high porosity of the renovation plasters.

An Experimental Study of CO2-Brine Relative Permeability in Sandstone

NASA Astrophysics Data System (ADS)

Chen, X.; DiCarlo, D. A.

2013-12-01

Accurate determinations of CO2-brine relative permeability are important for modeling potential CO2 storage scenarios. The most common assumption is that CO2-brine relative permeability is likely to be similar to oil-brine relative permeability for water-wet rocks. But recent measurements of CO2-brine relative permeability have differed greatly from oil-brine relative permeability; particularly, the measurements show a very low CO2 end point relative permeability (kr,CO2=0.1~0.2) and a relatively high residual water saturation (Swr>0.4) ( Lee et al. 2010, Zuo et al. 2012, Akbarabadi et al. 2013 and etc.). It has been hypothesized that the differences are related to CO2-brine having a different contact angle from oil-brine. In this study, we hypothesize that the differences are caused by large capillary end effects resulted from the very low CO2 viscosity. We conduct steady-state CO2-brine flow experiments in 2-foot-long and 2.8-inch-diamter Berea sandstone cores at 20 °C and 1500 psi. Four pressure taps drilled on a core allow both the total pressure drop and that across five individual sections to be measured. Three experiments, two drainage and one imbibition, have been conducted so far. Our results show: (1) The relative permeability to both brine and CO2 of the last section (downstream, 15 cm long) is significantly smaller than that of any of the middle three sections. This testifies that the capillary end effect makes the relative permeability under-measured at the end of a core. (2) The values of the middle three sections are very close to each other, which indicate the middle part of our core is free of capillary end effect. (3) The CO2 end point relative permeability is 0.3~0.5, which is much higher than the recent measurements. (4) The brine end point relative permeability during imbibition is about 0.08, which is close to literature data. Reference: Lee, Y.S, Kim, K. H. and Lee, T.H. et al. Analysis of CO2 Endpoint Relative Permeability and Injectivity

Permeability Evolution With Shearing of Simulated Faults in Unconventional Shale Reservoirs

NASA Astrophysics Data System (ADS)

Wu, W.; Gensterblum, Y.; Reece, J. S.; Zoback, M. D.

2016-12-01

Horizontal drilling and multi-stage hydraulic fracturing can lead to fault reactivation, a process thought to influence production from extremely low-permeability unconventional reservoir. A fundamental understanding of permeability changes with shear could be helpful for optimizing reservoir stimulation strategies. We examined the effects of confining pressure and frictional sliding on fault permeability in Eagle Ford shale samples. We performed shear-flow experiments in a triaxial apparatus on four shale samples: (1) clay-rich sample with sawcut fault, (2) calcite-rich sample with sawcut fault, (3) clay-rich sample with natural fault, and (4) calcite-rich sample with natural fault. We used pressure pulse-decay and steady-state flow techniques to measure fault permeability. Initial pore and confining pressures are set to 2.5 MPa and 5.0 MPa, respectively. To investigate the influence of confining pressure on fault permeability, we incrementally raised and lowered the confining pressure and measure permeability at different effective stresses. To examine the effect of frictional sliding on fault permeability, we slide the samples four times at a constant shear displacement rate of 0.043 mm/min for 10 minutes each and measure fault permeability before and after frictional sliding. We used a 3D Laser Scanner to image fault surface topography before and after the experiment. Our results show that frictional sliding can enhance fault permeability at low confining pressures (e.g., ≥5.0 MPa) and reduce fault permeability at high confining pressures (e.g., ≥7.5 MPa). The permeability of sawcut faults almost fully recovers when confining pressure returns to the initial value, and increases with sliding due to asperity damage and subsequent dilation at low confining pressures. In contrast, the permeability of natural faults does not fully recover. It initially increases with sliding, but then decreases with further sliding most likely due to fault gouge blocking fluid

Influence of fiber packing structure on permeability

NASA Technical Reports Server (NTRS)

Cai, Zhong; Berdichevsky, Alexander L.

1993-01-01

The study on the permeability of an aligned fiber bundle is the key building block in modeling the permeability of advanced woven and braided preforms. Available results on the permeability of fiber bundles in the literature show that a substantial difference exists between numerical and analytical calculations on idealized fiber packing structures, such as square and hexagonal packing, and experimental measurements on practical fiber bundles. The present study focuses on the variation of the permeability of a fiber bundle under practical process conditions. Fiber bundles are considered as containing openings and fiber clusters within the bundle. Numerical simulations on the influence of various openings on the permeability were conducted. Idealized packing structures are used, but with introduced openings distributed in different patterns. Both longitudinal and transverse flow are considered. The results show that openings within the fiber bundle have substantial effect on the permeability. In the longitudinal flow case, the openings become the dominant flow path. In the transverse flow case, the fiber clusters reduce the gap sizes among fibers. Therefore the permeability is greatly influenced by these openings and clusters, respectively. In addition to the porosity or fiber volume fraction, which is commonly used in the permeability expression, another fiber bundle status parameter, the ultimate fiber volume fraction, is introduced to capture the disturbance within a fiber bundle.

Experimental Microfracture Permeability Development in Crystalline Rocks Under Different Tectonic Stress Regimes

NASA Astrophysics Data System (ADS)

Faulkner, D. R.; Armitage, P. J.

2011-12-01

Geothermal fields rely on permeable fracture networks that can act for significant periods of time. In crystalline rocks, permeability may be stimulated by injections of fluid pressure at depth. We show how high-pressure laboratory experiments can be used to quantify the effects of different stress states on the permeability of two rocks; Darley Dale sandstone (~10-16 m2 permeability) and Westerly granite (~10-20 m2 permeability). It is well known that microfractures start to grow at stresses around one half of the failure stress. Failure in the experiments was reproduced in several ways: (1) by fixing σ3 and increasing σ1 - equivalent to a compressive or strike-slip tectonic regime (2) by fixing σ1 and decreasing σ3 - equivalent to an extensional tectonic regime (3) by increasing the pore fluid pressure at a fixed differential stress to simulate high pore fluid pressure failure, and (4) by fixing the mean stress while increasing σ1 and decreasing σ3 in sympathy. Permeability was monitored during all of these tests. From these tests we are able to quantify the relative contributions of mean stress, differential stress and pore fluid pressure on the permeability in the pre-failure region. This provides key data on the development of microfracture permeability that might be produced during the stimulation of geothermal fields during injection within different tectonic environments.

Frictional stability-permeability relationships for fractures in shales

NASA Astrophysics Data System (ADS)

Fang, Yi; Elsworth, Derek; Wang, Chaoyi; Ishibashi, Takuya; Fitts, Jeffrey P.

2017-03-01

There is wide concern that fluid injection in the subsurface, such as for the stimulation of shale reservoirs or for geological CO2 sequestration (GCS), has the potential to induce seismicity that may change reservoir permeability due to fault slip. However, the impact of induced seismicity on fracture permeability evolution remains unclear due to the spectrum of modes of fault reactivation (e.g., stable versus unstable). As seismicity is controlled by the frictional response of fractures, we explore friction-stability-permeability relationships through the concurrent measurement of frictional and hydraulic properties of artificial fractures in Green River shale (GRS) and Opalinus shale (OPS). We observe that carbonate-rich GRS shows higher frictional strength but weak neutral frictional stability. The GRS fracture permeability declines during shearing while an increased sliding velocity reduces the rate of permeability decline. By comparison, the phyllosilicate-rich OPS has lower friction and strong stability while the fracture permeability is reduced due to the swelling behavior that dominates over the shearing induced permeability reduction. Hence, we conclude that the friction-stability-permeability relationship of a fracture is largely controlled by mineral composition and that shale mineral compositions with strong frictional stability may be particularly subject to permanent permeability reduction during fluid infiltration.

Gravel-Sand-Clay Mixture Model for Predictions of Permeability and Velocity of Unconsolidated Sediments

NASA Astrophysics Data System (ADS)

Konishi, C.

2014-12-01

Gravel-sand-clay mixture model is proposed particularly for unconsolidated sediments to predict permeability and velocity from volume fractions of the three components (i.e. gravel, sand, and clay). A well-known sand-clay mixture model or bimodal mixture model treats clay contents as volume fraction of the small particle and the rest of the volume is considered as that of the large particle. This simple approach has been commonly accepted and has validated by many studies before. However, a collection of laboratory measurements of permeability and grain size distribution for unconsolidated samples show an impact of presence of another large particle; i.e. only a few percent of gravel particles increases the permeability of the sample significantly. This observation cannot be explained by the bimodal mixture model and it suggests the necessity of considering the gravel-sand-clay mixture model. In the proposed model, I consider the three volume fractions of each component instead of using only the clay contents. Sand becomes either larger or smaller particles in the three component mixture model, whereas it is always the large particle in the bimodal mixture model. The total porosity of the two cases, one is the case that the sand is smaller particle and the other is the case that the sand is larger particle, can be modeled independently from sand volume fraction by the same fashion in the bimodal model. However, the two cases can co-exist in one sample; thus, the total porosity of the mixed sample is calculated by weighted average of the two cases by the volume fractions of gravel and clay. The effective porosity is distinguished from the total porosity assuming that the porosity associated with clay is zero effective porosity. In addition, effective grain size can be computed from the volume fractions and representative grain sizes for each component. Using the effective porosity and the effective grain size, the permeability is predicted by Kozeny-Carman equation

Purdue Rare Isotope Measurement Laboratory

NASA Astrophysics Data System (ADS)

Caffee, M.; Elmore, D.; Granger, D.; Muzikar, P.

2002-12-01

The Purdue Rare Isotope Measurement Laboratory (PRIME Lab) is a dedicated research and service facility for accelerator mass spectrometry. AMS is an ultra-sensitive analytical technique used to measure low levels of long-lived cosmic-ray-produced and anthropogenic radionuclides, and rare trace elements. We measure 10Be (T1/2 = 1.5 My), 26Al (.702 My), 36Cl (.301 My), and 129I (16 My), in geologic samples. Applications include dating the cosmic-ray-exposure time of rocks on Earth's surface, determining rock and sediment burial ages, measuring the erosion rates of rocks and soils, and tracing and dating ground water. We perform sample preparation and separation chemistries for these radio-nuclides for our internal research activities and for those external researchers not possessing this capability. Our chemical preparation laboratories also serve as training sites for members of the geoscience community developing these techniques at their institutions. Research at Purdue involves collaborators among members of the Purdue Departments of Physics, Earth and Atmospheric Sciences, Chemistry, Agronomy, and Anthropology. We also collaborate and serve numerous scientists from other institutions. We are currently in the process of modernizing the facility with the goals of higher precision for routinely measured radio-nuclides, increased sample throughput, and the development of new measurement capabilities for the geoscience community.

Non-monotonic permeability variation during colloidal transport: Governing equations and analytical model

NASA Astrophysics Data System (ADS)

Chequer, L.; Russell, T.; Behr, A.; Genolet, L.; Kowollik, P.; Badalyan, A.; Zeinijahromi, A.; Bedrikovetsky, P.

2018-02-01

Permeability decline associated with the migration of natural reservoir fines impairs the well index of injection and production wells in aquifers and oilfields. In this study, we perform laboratory corefloods using aqueous solutions with different salinities in engineered rocks with different kaolinite content, yielding fines migration and permeability alteration. Unusual permeability growth has been observed at high salinities in rocks with low kaolinite concentrations. This has been attributed to permeability increase during particle detachment and re-attachment of already mobilised fines by electrostatic attraction to the rock in stagnant zones of the porous space. We refine the traditional model for fines migration by adding mathematical expressions for the particle re-attachment rate, particle detachment with delay relative to salinity decrease, and the attached-concentration-dependency of permeability. A one-dimensional flow problem that accounts for those three effects allows for an exact analytical solution. The modified model captures the observed effect of permeability increase at high water salinities in rocks with low kaolinite concentrations. The developed model matches the coreflooding data with high accuracy, and the obtained model coefficients vary within their usual intervals.

PERMEABLE REACTIVE BARRIERS FOR IN-SITU TREATMENT OF ARSENIC-CONTAMINATED GROUNDWATER

EPA Science Inventory

Laboratory and field research has shown that permeable reactive barriers (PRBs) containing a variety of materials can treat arsenic (As) contaminated groundwater. Sites where these PRBs are located include a mine tailings facility, fertilizer and chemical manufacturing sites, a...

EXPERIMENTAL EVALUATION OF GEOMETRICAL SHAPE FACTORS FOR SHORT CYLINDRICAL PROBES USED TO MEASURE SOIL PERMEABILITY TO AIR

EPA Science Inventory

Permeability of soil has become recognized as an important parameter in determining the rate of transport and entry of radon from the soil into indoor environments. This parameter is usually measured in the field by inserting a cylindrical tube with a short porous section into th...

Polysulfone - CNT composite membrane with enhanced water permeability

NASA Astrophysics Data System (ADS)

Hirani, Bhakti; Kar, Soumitra; Aswal, V. K.; Bindal, R. C.; Goyal, P. S.

2018-04-01

Polymeric membranes are routinely used for water purification. The performance of these conventional membranes can be improved by incorporating nanomaterials, such as metal oxide nanoparticle and carbon nanotubes (CNTs). This manuscript reports the synthesis and characterization of polysulfone (Psf) based nanocomposite membranes where multi wall carbon nanotubes (MWCNTs) and oleic acid coated Fe3O4 nanoparticles have been impregnated onto the polymeric host matrix. The performance of the membranes was evaluated by water permeability and solute rejection measurements. It was observed that the permeability of Psf membrane increases three times at 0.1% loading of MWCNT without compromise in selectivity. It was further observed that the increase in permeability is not affected upon addition of Fe3O4 nanoparticles into the membrane. In order to get a better insight into the membrane microstructure, small angle neutron scattering (SANS) studies were carried out. There is a good correlation between the water permeability and the pore sizes of the membranes as measured using SANS.

The optical measurement of 1,2-propanediol for the determination of lung capillary permeability surface area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galloway, R.L. Jr.; Staton, D.J.; Harris, T.R.

1989-06-01

A technique has been developed which allows for the optical measurement of the concentration-time relationship for a diffusion-limited material in indicator dilution studies. The material, 1-2 propanediol, is used as a probe of the permeability of capillaries in the lung. Comparisons between standard radioisotope measurements and the optical measurements are provided and show excellent agreement. The optical method represents an improvement over the standard radioisotope method in that it provides the same data at lower cost, lower risk, and without the delay required by the radiographic methods.

Enhancement of hydrogen gas permeability in electrically aligned MWCNT-PMMA composite membranes.

PubMed

Kumar, Sumit; Sharma, Anshu; Tripathi, Balram; Srivastava, Subodh; Agrawal, Shweta; Singh, M; Awasthi, Kamlendra; Vijay, Y K

2010-10-01

The multi-walled carbon nanotube (MWCNT) dispersed polymethylmethacrylate (PMMA) composite membranes have been prepared for hydrogen gas permeation application. Composite membranes are characterized by Raman spectroscopy, optical microscopy, X-ray diffraction, electrical measurements and gas permeability measurements. The effect of electric field alignment of MWCNT in PMMA matrix on gas permeation has been studied for hydrogen gas. The permeability measurements indicated that the electrically aligned MWCNT in PMMA has shown almost 2 times higher permeability for hydrogen gas as compare to randomly dispersed MWCNT in PMMA. The enhancement in permeability is explained on the basis of well aligned easy channel provided by MWCNT in electrically aligned sample. The effect of thickness of membrane on the gas permeability also studied and thickness of about 30microm found to be optimum thickness for fast hydrogen gas permeates.

Predicting chemically-induced skin reactions. Part II: QSAR models of skin permeability and the relationships between skin permeability and skin sensitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alves, Vinicius M.; Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599; Muratov, Eugene

Skin permeability is widely considered to be mechanistically implicated in chemically-induced skin sensitization. Although many chemicals have been identified as skin sensitizers, there have been very few reports analyzing the relationships between molecular structure and skin permeability of sensitizers and non-sensitizers. The goals of this study were to: (i) compile, curate, and integrate the largest publicly available dataset of chemicals studied for their skin permeability; (ii) develop and rigorously validate QSAR models to predict skin permeability; and (iii) explore the complex relationships between skin sensitization and skin permeability. Based on the largest publicly available dataset compiled in this study, wemore » found no overall correlation between skin permeability and skin sensitization. In addition, cross-species correlation coefficient between human and rodent permeability data was found to be as low as R{sup 2} = 0.44. Human skin permeability models based on the random forest method have been developed and validated using OECD-compliant QSAR modeling workflow. Their external accuracy was high (Q{sup 2}{sub ext} = 0.73 for 63% of external compounds inside the applicability domain). The extended analysis using both experimentally-measured and QSAR-imputed data still confirmed the absence of any overall concordance between skin permeability and skin sensitization. This observation suggests that chemical modifications that affect skin permeability should not be presumed a priori to modulate the sensitization potential of chemicals. The models reported herein as well as those developed in the companion paper on skin sensitization suggest that it may be possible to rationally design compounds with the desired high skin permeability but low sensitization potential. - Highlights: • It was compiled the largest publicly-available skin permeability dataset. • Predictive QSAR models were developed for skin permeability. • No concordance between

Droplet-based microfluidics platform for measurement of rapid erythrocyte water transport

PubMed Central

Jin, Byung-Ju; Esteva-Font, Cristina; Verkman, A.S.

2015-01-01

Cell membrane water permeability is an important determinant of epithelial fluid secretion, tissue swelling, angiogenesis, tumor spread and other biological processes. Cellular water channels, the aquaporins, are important drug targets. Water permeability is generally measured from the kinetics of cell volume change in response to an osmotic gradient. Here, we developed a microfluidics platform in which cells expressing a cytoplasmic, volume-sensing fluorescent dye are rapidly subjected to an osmotic gradient by solution mixing inside a ~ 0.1 nL droplet surrounded by oil. Solution mixing time was < 10 ms. Osmotic water permeability was deduced from a single, time-integrated fluorescence image of an observation area in which time after mixing is determined by spatial position. Water permeability was accurately measured in aquaporin-expressing erythrocytes with half-times for osmotic equilibration down to < 50 ms. Compared with conventional water permeability measurements using costly stopped-flow instrumentation, the microfluidics platform here utilizes sub-microliter blood sample volume, does not suffer from mixing artifact, and replaces challenging kinetic measurements by a single image capture using a standard laboratory fluorescence microscope. PMID:26159099

Solute source depletion control of forward and back diffusion through low-permeability zones

NASA Astrophysics Data System (ADS)

Yang, Minjune; Annable, Michael D.; Jawitz, James W.

2016-10-01

Solute diffusive exchange between low-permeability aquitards and high-permeability aquifers acts as a significant mediator of long-term contaminant fate. Aquifer contaminants diffuse into aquitards, but as contaminant sources are depleted, aquifer concentrations decline, triggering back diffusion from aquitards. The dynamics of the contaminant source depletion, or the source strength function, controls the timing of the transition of aquitards from sinks to sources. Here, we experimentally evaluate three archetypical transient source depletion models (step-change, linear, and exponential), and we use novel analytical solutions to accurately account for dynamic aquitard-aquifer diffusive transfer. Laboratory diffusion experiments were conducted using a well-controlled flow chamber to assess solute exchange between sand aquifer and kaolinite aquitard layers. Solute concentration profiles in the aquitard were measured in situ using electrical conductivity. Back diffusion was shown to begin earlier and produce larger mass flux for rapidly depleting sources. The analytical models showed very good correspondence with measured aquifer breakthrough curves and aquitard concentration profiles. The modeling approach links source dissolution and back diffusion, enabling assessment of human exposure risk and calculation of the back diffusion initiation time, as well as the resulting plume persistence.

Anthropometric measures in cardiovascular disease prediction: comparison of laboratory-based versus non-laboratory-based model.

PubMed

Dhana, Klodian; Ikram, M Arfan; Hofman, Albert; Franco, Oscar H; Kavousi, Maryam

2015-03-01

Body mass index (BMI) has been used to simplify cardiovascular risk prediction models by substituting total cholesterol and high-density lipoprotein cholesterol. In the elderly, the ability of BMI as a predictor of cardiovascular disease (CVD) declines. We aimed to find the most predictive anthropometric measure for CVD risk to construct a non-laboratory-based model and to compare it with the model including laboratory measurements. The study included 2675 women and 1902 men aged 55-79 years from the prospective population-based Rotterdam Study. We used Cox proportional hazard regression analysis to evaluate the association of BMI, waist circumference, waist-to-hip ratio and a body shape index (ABSI) with CVD, including coronary heart disease and stroke. The performance of the laboratory-based and non-laboratory-based models was evaluated by studying the discrimination, calibration, correlation and risk agreement. Among men, ABSI was the most informative measure associated with CVD, therefore ABSI was used to construct the non-laboratory-based model. Discrimination of the non-laboratory-based model was not different than laboratory-based model (c-statistic: 0.680-vs-0.683, p=0.71); both models were well calibrated (15.3% observed CVD risk vs 16.9% and 17.0% predicted CVD risks by the non-laboratory-based and laboratory-based models, respectively) and Spearman rank correlation and the agreement between non-laboratory-based and laboratory-based models were 0.89 and 91.7%, respectively. Among women, none of the anthropometric measures were independently associated with CVD. Among middle-aged and elderly where the ability of BMI to predict CVD declines, the non-laboratory-based model, based on ABSI, could predict CVD risk as accurately as the laboratory-based model among men. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Measurements of pore-scale flow through apertures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chojnicki, Kirsten

Pore-scale aperture effects on flow in pore networks was studied in the laboratory to provide a parameterization for use in transport models. Four cases were considered: regular and irregular pillar/pore alignment with and without an aperture. The velocity field of each case was measured and simulated, providing quantitatively comparable results. Two aperture effect parameterizations were considered: permeability and transmission. Permeability values varied by an order of magnitude between the cases with and without apertures. However, transmission did not correlate with permeability. Despite having much greater permeability the regular aperture case permitted less transmission than the regular case. Moreover, both irregularmore » cases had greater transmission than the regular cases, a difference not supported by the permeabilities. Overall, these findings suggest that pore-scale aperture effects on flow though a pore-network may not be adequately captured by properties such as permeability for applications that are interested in determining particle transport volume and timing.« less

Fast Laplace solver approach to pore-scale permeability

NASA Astrophysics Data System (ADS)

Arns, C. H.; Adler, P. M.

2018-02-01

We introduce a powerful and easily implemented method to calculate the permeability of porous media at the pore scale using an approximation based on the Poiseulle equation to calculate permeability to fluid flow with a Laplace solver. The method consists of calculating the Euclidean distance map of the fluid phase to assign local conductivities and lends itself naturally to the treatment of multiscale problems. We compare with analytical solutions as well as experimental measurements and lattice Boltzmann calculations of permeability for Fontainebleau sandstone. The solver is significantly more stable than the lattice Boltzmann approach, uses less memory, and is significantly faster. Permeabilities are in excellent agreement over a wide range of porosities.

Laboratory Measurements of Cometary Photochemical Phenomena.

DTIC Science & Technology

1981-12-04

PROGFIAM ELEMENT.PROJECT TASK Laser .Chemistry Division AREA & WORK UNIT NUMaZRS Department of Chemistry - Howard University NR.051-733 Wash’ ngtQn, D. C...William M. Jackson Laser Chemistry Division Department of Chemistry Howard University .Washington, D. C. 20059 / Published by Jet Propulsion Laboratory...MEASUREMENTS OF COMETARY PHOTOCHEMICAL PHENOMENA William M. Jackson Howard University Washington, DC 20059 Abstract Laboratory experiments are described

Predicting chemically-induced skin reactions. Part II: QSAR models of skin permeability and the relationships between skin permeability and skin sensitization

PubMed Central

Alves, Vinicius M.; Muratov, Eugene; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Andrade, Carolina H.; Tropsha, Alexander

2015-01-01

Skin permeability is widely considered to be mechanistically implicated in chemically-induced skin sensitization. Although many chemicals have been identified as skin sensitizers, there have been very few reports analyzing the relationships between molecular structure and skin permeability of sensitizers and non-sensitizers. The goals of this study were to: (i) compile, curate, and integrate the largest publicly available dataset of chemicals studied for their skin permeability; (ii) develop and rigorously validate QSAR models to predict skin permeability; and (iii) explore the complex relationships between skin sensitization and skin permeability. Based on the largest publicly available dataset compiled in this study, we found no overall correlation between skin permeability and skin sensitization. In addition, cross-species correlation coefficient between human and rodent permeability data was found to be as low as R2=0.44. Human skin permeability models based on the random forest method have been developed and validated using OECD-compliant QSAR modeling workflow. Their external accuracy was high (Q2ext = 0.73 for 63% of external compounds inside the applicability domain). The extended analysis using both experimentally-measured and QSAR-imputed data still confirmed the absence of any overall concordance between skin permeability and skin sensitization. This observation suggests that chemical modifications that affect skin permeability should not be presumed a priori to modulate the sensitization potential of chemicals. The models reported herein as well as those developed in the companion paper on skin sensitization suggest that it may be possible to rationally design compounds with the desired high skin permeability but low sensitization potential. PMID:25560673

Permeability of canine vocal fold lamina propria.

PubMed

Meyer, Jacob P; Kvit, Anton A; Devine, Erin E; Jiang, Jack

2015-04-01

Determine the permeability of excised canine vocal fold lamina propria. Basic science. Vocal folds were excised from canine larynges and mounted within a device to measure the flow of 0.9% saline through the tissue over time. The resultant fluid volume displaced over time was then used in a variation of Darcy's law to calculate the permeability of the tissue. Permeability was found through each anatomical plane of the vocal fold, with five samples per plane. Permeability was also found for lamina propria stretched to 10%, 20%, and 30% of its initial length to determine the effects of tensile strain on permeability, with five samples per level of strain. Permeability was found to be 1.40 × 10(-13) m(3) s/kg through the sagittal plane, 1.00 × 10(-13) m(3) s/kg through the coronal plane, and 4.02 × 10(-13) m(3) s/kg through the axial plane. It was significantly greater through the axial plane than both the sagittal (P = .025) and coronal (P = .009) planes. Permeability under strain through the sagittal plane was found to be 1.94 × 10(-13) m(3) s/kg under 10% strain, 3.35 × 10(-13) m(3) s/kg under 20% strain, and 4.80 × 10(-13) m(3) s/kg under 30% strain. The permeability significantly increased after 20% strain (P < .05). Permeability in canine vocal fold lamina propria was found to be increased along the anterior-posterior axis, following the length of the vocal folds. This may influence fluid distribution within the lamina propria during and after vibration. Similarly, permeability increased after 20% strain was imposed on the lamina propria, and may influence vocal fold dynamics during certain phonation tasks. NA Laryngoscope, 125:941-945, 2015. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

Gas permeability of ice-templated, unidirectional porous ceramics.

PubMed

Seuba, Jordi; Deville, Sylvain; Guizard, Christian; Stevenson, Adam J

2016-01-01

We investigate the gas flow behavior of unidirectional porous ceramics processed by ice-templating. The pore volume ranged between 54% and 72% and pore size between 2.9 [Formula: see text]m and 19.1 [Formula: see text]m. The maximum permeability ([Formula: see text] [Formula: see text] m[Formula: see text]) was measured in samples with the highest total pore volume (72%) and pore size (19.1 [Formula: see text]m). However, we demonstrate that it is possible to achieve a similar permeability ([Formula: see text] [Formula: see text] m[Formula: see text]) at 54% pore volume by modification of the pore shape. These results were compared with those reported and measured for isotropic porous materials processed by conventional techniques. In unidirectional porous materials tortuosity ([Formula: see text]) is mainly controlled by pore size, unlike in isotropic porous structures where [Formula: see text] is linked to pore volume. Furthermore, we assessed the applicability of Ergun and capillary model in the prediction of permeability and we found that the capillary model accurately describes the gas flow behavior of unidirectional porous materials. Finally, we combined the permeability data obtained here with strength data for these materials to establish links between strength and permeability of ice-templated materials.

Variation of brine compositions resulting from flow from matrix or fracture permeability, investigated by high pressure laboratory experiments

NASA Astrophysics Data System (ADS)

Poszwa, A. C.; Coleman, M. L.; Pouya, A.; Ader, M.; Bounenni, A.

2003-04-01

Planning oil production from a chalk reservoir oilfield is difficult because the matrix usually has low permeability despite its high porosity. Most oil is thought to come from fracture porosity but the matrix contribution should increase as compaction occurs during production. To better understand the respective contributions from matrix and fracture, we studied the geochemical characteristics of fluids using high-pressure brine flow experiments on chalk cores. During the experiment axial load was changed relative to confining pressure to induce fractures and to close them again. We used chlorine stable isotope variations to study fluid pathway, because chlorine is a chemically conservative element in sedimentary systems and its isotopes fractionate only with physical processes like diffusion or adsorption that could occur mainly in the chalk matrix. A first experiment was performed on a very porous chalk from Henley (on-shore UK) and using a low-salinity brine. Large variations of brine Cl isotope composition were observed (from -0.56 to +0.08 per mil). The variations were correlated positively with the brine flux through the chalk and the permeability of the rock, both parameters controlled by the rock fracturing. A second experiment used brine with salinity similar to that of seawater. In this case, chemical and isotopic variations were not significant. From the beginning, the chalk structure seems to have been destroyed very quickly (induced fracture porosity collapsed) possibly because of the fluid nature, so that whatever pressure was applied, the permeability did not change significantly. Using Valhall reservoir chalk (offshore Norwegian North Sea) and fluid half the salinity of seawater in a third experiment, we obtained a large range of permeabilities. Brine isotopic trends were very similar on average to those of the first experiment even though variations were smaller (Cl isotopes from -0.09 to +0.29 per mil) and not significantly correlated simply to

Influence of effective stress and dry density on the permeability of municipal solid waste.

PubMed

Zhang, Zhenying; Wang, Yingfeng; Xu, Hui; Fang, Yuehua; Wu, Dazhi

2018-05-01

A landfill is one of the main sites for disposal of municipal solid waste and the current landfill disposal system faces several problems. For instance, excessive leachate water is an important factor leading to landfill instability. Understanding the permeability characteristics of municipal solid waste is a relevant topic in the field of environmental geotechnical engineering. In this paper, the current research progress on permeability characteristics of municipal solid waste is discussed. A review of recent studies indicates that the research in this field is divided into two categories based on the experimental method employed: field tests and laboratory tests. This paper summarizes test methods, landfill locations, waste ages, dry densities and permeability coefficients across different studies that focus on permeability characteristics. Additionally, an experimental study on compressibility and permeability characteristics of fresh municipal solid waste under different effective stresses and compression times was carried out. Moreover, the relationships between the permeability coefficient and effective stress as well as dry density were obtained and a permeability prediction model was established. Finally, the experimental results from the existing literature and this paper were compared and the effects of effective stress and dry density on the permeability characteristics of municipal solid waste were summarized. This study provides the basis for analysis of leachate production in a landfill.

Preliminary study of soil permeability properties using principal component analysis

NASA Astrophysics Data System (ADS)

Yulianti, M.; Sudriani, Y.; Rustini, H. A.

2018-02-01

Soil permeability measurement is undoubtedly important in carrying out soil-water research such as rainfall-runoff modelling, irrigation water distribution systems, etc. It is also known that acquiring reliable soil permeability data is rather laborious, time-consuming, and costly. Therefore, it is desirable to develop the prediction model. Several studies of empirical equations for predicting permeability have been undertaken by many researchers. These studies derived the models from areas which soil characteristics are different from Indonesian soil, which suggest a possibility that these permeability models are site-specific. The purpose of this study is to identify which soil parameters correspond strongly to soil permeability and propose a preliminary model for permeability prediction. Principal component analysis (PCA) was applied to 16 parameters analysed from 37 sites consist of 91 samples obtained from Batanghari Watershed. Findings indicated five variables that have strong correlation with soil permeability, and we recommend a preliminary permeability model, which is potential for further development.

New Laboratory Observations of Thermal Pressurization Weakening

NASA Astrophysics Data System (ADS)

Badt, N.; Tullis, T. E.; Hirth, G.

2017-12-01

Dynamic frictional weakening due to pore fluid thermal pressurization has been studied under elevated confining pressure in the laboratory, using a rotary-shear apparatus having a sample with independent pore pressure and confining pressure systems. Thermal pressurization is directly controlled by the permeability of the rocks, not only for the initiation of high-speed frictional weakening but also for a subsequent sequence of high-speed sliding events. First, the permeability is evaluated at different effective pressures using a method where the pore pressure drop and the flow-through rate are compared using Darcy's Law as well as a pore fluid oscillation method, the latter method also permitting measurement of the storage capacity. Then, the samples undergo a series of high-speed frictional sliding segments at a velocity of 2.5 mm/s, under an applied confining pressure and normal stress of 45 MPa and 50 MPa, respectively, and an initial pore pressure of 25 MPa. Finally the rock permeability and storage capacity are measured again to assess the evolution of the rock's pore fluid properties. For samples with a permeability of 10-20 m2 thermal pressurization promotes a 40% decrease in strength. However, after a sequence of three high-speed sliding events, the magnitude of weakening diminishes progressively from 40% to 15%. The weakening events coincide with dilation of the sliding interface. Moreover, the decrease in the weakening degree with progressive fast-slip events suggest that the hydraulic diffusivity may increase locally near the sliding interface during thermal pressurization-enhanced slip. This could result from stress- or thermally-induced damage to the host rock, which would perhaps increase both permeability and storage capacity, and so possibly decrease the susceptibility of dynamic weakening due to thermal pressurization in subsequent high-speed sliding events.

Characterization of permeability of pavement bases in Missouri Department of Transportation's System

DOT National Transportation Integrated Search

2003-02-01

The results of field (in-situ) and laboratory permeability testing showed MoDOT's predominant pavement base "Type 5" (and the upper "working" surface of the 2-foot rock fill alternative) has hydraulic conductivities that are several orders of magnitu...

Iron abundance and magnetic permeability of the moon

NASA Technical Reports Server (NTRS)

Parkin, C. W.; Daily, W. D.; Dyal, P.

1974-01-01

A set of simultaneous data from the Apollo 12 lunar surface magnetometer and the Explorer 35 Ames magnetometer are used to construct a whole-moon hysteresis curve, from which a new value of global lunar permeability is determined to be mu = 1.012 + or - 0.006. The corresponding global induced dipole moment is 2.1 x 10 to the 18th power gauss-cucm for typical inducing fields of .1000 gauss in the lunar environment. From the permeability measurement, lunar free iron abundance is determined to be 2.5 + or - 2.0 wt. %. Total iron abundance is calculated for two assumed compositional models of the lunar interior: a free iron/orthopyroxene lunar composition and a free iron/olivine composition. The overall lunar total iron abundance is determined to be 9.0 + or - 4.7 wt. %. Other lunar models with a small iron core and with a shallow iron-rich layer are discussed in light of the measured global permeability. Effects on permeability and iron content calculations due to a possible lunar ionosphere are also considered.

Permeability-porosity relationship for compaction of a low-permeability creeping material : Experimental evaluation using a single transient test

NASA Astrophysics Data System (ADS)

Ghabezloo, S.; Sulem, J.; Saint-Marc, J.

2009-04-01

It is well-known that there is no unique permeability-porosity relationship that can be applied to all porous materials. For a given evolution process that changes both permeability and porosity of a porous material, for example elastic or plastic compaction, microcracking or chemical alteration, it is usually assumed that there is an empirical relationship in the form of a power-law or exponential relationship between these parameters. The coefficients of these empirical relationships depend strongly on the properties of the material and of the evolution process. For the case of the power-law permeability-porosity relationship, a review of the literature shows that the exponent of this relation may be integer or non-integer, constant or variable, and the reported values of exponent vary between 1.1 and 25.4 for different materials and evolution processes, but no clear correlation between the exponenet and the petrophysical properties could be found. This wide variability of the permeability-porosity relationship highlights the necessity of experimental evaluation of this relationship for each material and evolution process. An experimental method is presented for the evaluation of a permeability-porosity relationship in a low-permeability porous material using the results of a single transient test. This method accounts for both elastic and non-elastic deformations of the sample during the test and is applied to a hardened class G oil well cement paste. An initial hydrostatic undrained loading is applied to the sample which generates an excess pore pressure, related to the applied hydrostatic stress by the Skempton coefficient of the material. The generated excess pore pressure is then released at one end of the sample while monitoring the pore pressure at the other end and the radial strain in the middle of the sample during the dissipation of the pore pressure. These measurements are back analysed using a finite-difference numerical scheme to evaluate the

Imaging and computational considerations for image computed permeability: Operating envelope of Digital Rock Physics

NASA Astrophysics Data System (ADS)

Saxena, Nishank; Hows, Amie; Hofmann, Ronny; Alpak, Faruk O.; Freeman, Justin; Hunter, Sander; Appel, Matthias

2018-06-01

This study defines the optimal operating envelope of the Digital Rock technology from the perspective of imaging and numerical simulations of transport properties. Imaging larger volumes of rocks for Digital Rock Physics (DRP) analysis improves the chances of achieving a Representative Elementary Volume (REV) at which flow-based simulations (1) do not vary with change in rock volume, and (2) is insensitive to the choice of boundary conditions. However, this often comes at the expense of image resolution. This trade-off exists due to the finiteness of current state-of-the-art imaging detectors. Imaging and analyzing digital rocks that sample the REV and still sufficiently resolve pore throats is critical to ensure simulation quality and robustness of rock property trends for further analysis. We find that at least 10 voxels are needed to sufficiently resolve pore throats for single phase fluid flow simulations. If this condition is not met, additional analyses and corrections may allow for meaningful comparisons between simulation results and laboratory measurements of permeability, but some cases may fall outside the current technical feasibility of DRP. On the other hand, we find that the ratio of field of view and effective grain size provides a reliable measure of the REV for siliciclastic rocks. If this ratio is greater than 5, the coefficient of variation for single-phase permeability simulations drops below 15%. These imaging considerations are crucial when comparing digitally computed rock flow properties with those measured in the laboratory. We find that the current imaging methods are sufficient to achieve both REV (with respect to numerical boundary conditions) and required image resolution to perform digital core analysis for coarse to fine-grained sandstones.

Measuring the Osmotic Water Permeability of the Plant Protoplast Plasma Membrane: Implication of the Nonosmotic Volume

PubMed Central

2010-01-01

Starting from the original theoretical descriptions of osmotically induced water volume flow in membrane systems, a convenient procedure to determine the osmotic water permeability coefficient (Pos) and the relative nonosmotic volume (β) of individual protoplasts is presented. Measurements performed on protoplasts prepared from pollen grains and pollen tubes of Lilium longiflorum cv. Thunb. and from mesophyll cells of Nicotiana tabacum L. and Arabidopsis thaliana revealed low values for the osmotic water permeability coefficient in the range 5–20 μm · s−1 with significant differences in Pos, depending on whether β is considered or not. The value of β was determined using two different methods: by interpolation from Boyle-van’t Hoff plots or by fitting a solution of the theoretical equation for water volume flow to the whole volume transients measured during osmotic swelling. The values determined with the second method were less affected by the heterogeneity of the protoplast samples and were around 30% of the respective isoosmotic protoplast volume. It is therefore important to consider nonosmotic volume in the calculation of Pos as plant protoplasts behave as nonideal osmometers. PMID:17568979

Surface-subsurface turbulent interaction at the interface of a permeable bed: influence of the wall permeability

NASA Astrophysics Data System (ADS)

Kim, T.; Blois, G.; Best, J.; Christensen, K. T.

2017-12-01

Coarse-gravel river beds possess a high degree of permeability. Flow interactions between surface and subsurface flow across the bed interface is key to a number of natural processes occurring in the hyporheic zone. In fact, it is increasingly recognized that these interactions drive mass, momentum and energy transport across the interface, and consequently control biochemical processes as well as stability of sediments. The current study explores the role of the wall permeability in surface and subsurface flow interaction under controlled experimental conditions on a physical model of a gravel bed. The present wall model was constructed by five layers of cubically arranged spheres (d=25.4mm, where d is a diameter) providing 48% of porosity. Surface topography was removed by cutting half of a diameter on the top layer of spheres to render the flow surface smooth and highlight the impact of the permeability on the overlying flow. An impermeable smooth wall was also considered as a baseline of comparison for the permeable wall flow. To obtain basic flow statistics, low-frame-rate high-resolution PIV measurements were performed first in the streamwise-wall-normal (x-y) plane and refractive-index matching was employed to optically access the flow within the permeable wall. Time-resolved PIV experiments in the same facility were followed to investigate the flow interaction across the wall interface in sptaio-temporal domain. In this paper, a detailed analysis of the first and second order velocity statistics as well as the amplitude modulation for the flow overlying the permeable smooth wall will be presented.

Permeability model of sintered porous media: analysis and experiments

NASA Astrophysics Data System (ADS)

Flórez Mera, Juan Pablo; Chiamulera, Maria E.; Mantelli, Marcia B. H.

2017-11-01

In this paper, the permeability of porous media fabricated from copper powder sintering process was modeled and measured, aiming the use of the porosity as input parameter for the prediction of the permeability of sintering porous media. An expression relating the powder particle mean diameter with the permeability was obtained, based on an elementary porous media cell, which is physically represented by a duct formed by the arrangement of spherical particles forming a simple or orthorhombic packing. A circular duct with variable section was used to model the fluid flow within the porous media, where the concept of the hydraulic diameter was applied. Thus, the porous is modeled as a converging-diverging duct. The electrical circuit analogy was employed to determine two hydraulic resistances of the cell: based on the Navier-Stokes equation and on the Darcýs law. The hydraulic resistances are compared between themselves and an expression to determine the permeability as function of average particle diameter is obtained. The atomized copper powder was sifted to reduce the size dispersion of the particles. The porosities and permeabilities of sintered media fabricated from powders with particle mean diameters ranging from 20 to 200 microns were measured, by means of the image analysis method and using an experimental apparatus. The permeability data of a porous media, made of copper powder and saturated with distilled water, was used to compare with the permeability model. Permeability literature models, which considers that powder particles have the same diameter and include porosity data as input parameter, were compared with the present model and experimental data. This comparison showed to be quite good.

Update to Permeable Pavement Research at the Edison ...

EPA Pesticide Factsheets

The EPA’s Urban Watershed Management Branch (UWMB) has been monitoring the permeable pavement demonstration site at the Edison Environmental Center, NJ since 2010. This site has three different types of permeable pavements including interlocking concrete permeable pavers, pervious concrete, and porous asphalt. The permeable pavements are limited to parking spaces while adjacent driving lanes are impermeable and drain to the permeable surfaces. The parking lot is instrumented for continuous monitoring with thermistors and water content reflectometers that measure moisture as infiltrate passes through the storage gallery beneath the permeable pavements into the underlying native soil. Each permeable surface of the parking lot has four lined sections that capture infiltrate in tanks for water quality analyses; these tanks are capable of holding volumes up to 4.1 m3, which represents up to 38 mm (1.5 in.) for direct rainfall on the porous pavement and runoff from adjacent driving lanes that drain into the permeable surface.Previous technical releases concerning the demonstration site focused on monitoring techniques, observed chloride and nutrient concentrations, surface hydrology, and infiltration and evaporation rates. This presentation summarizes these past findings and addresses current water quality efforts including pH, solids analysis, total organic carbon, and chemical oxygen demand. Stormwater runoff continues to be a major cause of water pollution in

Space debris measurement program at Phillips Laboratory

NASA Technical Reports Server (NTRS)

Dao, Phan D.; Mcnutt, Ross T.

1992-01-01

Ground-based optical sensing was identified as a technique for measuring space debris complementary to radar in the critical debris size range of 1 to 10 cm. The Phillips Laboratory is building a staring optical sensor for space debris measurement and considering search and track optical measurement at additional sites. The staring sensor is implemented in collaboration with Wright Laboratory using the 2.5 m telescope at Wright Patterson AFB, Dayton, Ohio. The search and track sensor is designed to detect and track orbital debris in tasked orbits. A progress report and a discussion of sensor performance and search and track strategies will be given.

Aneurysm permeability following coil embolization: packing density and coil distribution

PubMed Central

Chueh, Ju-Yu; Vedantham, Srinivasan; Wakhloo, Ajay K; Carniato, Sarena L; Puri, Ajit S; Bzura, Conrad; Coffin, Spencer; Bogdanov, Alexei A; Gounis, Matthew J

2015-01-01

Background Rates of durable aneurysm occlusion following coil embolization vary widely, and a better understanding of coil mass mechanics is desired. The goal of this study is to evaluate the impact of packing density and coil uniformity on aneurysm permeability. Methods Aneurysm models were coiled using either Guglielmi detachable coils or Target coils. The permeability was assessed by taking the ratio of microspheres passing through the coil mass to those in the working fluid. Aneurysms containing coil masses were sectioned for image analysis to determine surface area fraction and coil uniformity. Results All aneurysms were coiled to a packing density of at least 27%. Packing density, surface area fraction of the dome and neck, and uniformity of the dome were significantly correlated (p<0.05). Hence, multivariate principal components-based partial least squares regression models were used to predict permeability. Similar loading vectors were obtained for packing and uniformity measures. Coil mass permeability was modeled better with the inclusion of packing and uniformity measures of the dome (r2=0.73) than with packing density alone (r2=0.45). The analysis indicates the importance of including a uniformity measure for coil distribution in the dome along with packing measures. Conclusions A densely packed aneurysm with a high degree of coil mass uniformity will reduce permeability. PMID:25031179

Dielectric property measurements in the Electromagnetic Properties Measurement Laboratory

NASA Technical Reports Server (NTRS)

Cravey, Robin L.; Tiemsin, Pacita I.; Bussell, Kerri; Dudley, Kenneth L.

1995-01-01

The capability to measure the dielectric properties of various materials has been developed in the Electromagnetic Properties Measurement Laboratory (EPML) of the Electromagnetics Research Branch (ERB). Two measurement techniques which have been implemented in the EPML to characterize materials are the dielectric probe and waveguide techniques. Several materials, including some for which the dielectric properties are well known, have been measured in an attempt to establish the capabilities of the EPML in determining dielectric properties. Brief descriptions of the two techniques are presented in this report, along with representative results obtained during these measurements.

Reliability of laboratory measurement of human food intake.

PubMed

Laessle, R; Geiermann, L

2012-02-01

The universal eating monitor (UEM) of Kissileff for laboratory measurement of food intake was modified and used with a newly developed special software to compute cumulative intake data. To explore the measurement precision of the UEM an investigation of test-retest-reliability of food intake parameters was conducted. The intake characteristics of 125 males and females were measured repeatedly in the laboratory with a measurement interval of 1 week. Pudding of preferred flavour served as test meal. Test-retest-reliability of intake characteristics ranged from .49 (change of eating rate) to .89 (initial eating rate). All test-retest correlations were highly significant. Sex, BMI and eating habits according to TFEQ-factors had no significant effects on reliability of intake characteristics. The test-retest-reliability of the laboratory intake measures is as good as those of personality questionnaires, where it should be better than .80. Reliability coefficients are valid independent of sex, BMI or trait characteristics of eating behaviour. Copyright © 2011 Elsevier Ltd. All rights reserved.

Long-term Metal Performance of Three Permeable Pavements ...

EPA Pesticide Factsheets

EPA constructed a 4,000-m2 parking lot surfaced with three permeable pavements (permeable interlocking concrete pavers, pervious concrete, and porous asphalt) on the Edison Environmental Center in Edison, NJ in 2009. Samples from each permeable pavement infiltrate were collected for six years beginning in January 2010 and analyzed for twenty-two metals. Although the infiltrate metals concentrations varied by surface, metal concentrations in more than 99% of the permeable pavement infiltrate samples met both the groundwater effluent limitations and maximum contaminant levels in national primary drinking water regulations for barium, chromium, copper, manganese, nickel and zinc. Arsenic, cadmium, lead and antimony met those standards in 60% to 98% of the samples with no measurable difference found among pavements. Aluminum and iron in pervious concrete and porous asphalt infiltrates met standards at more than 90%, however permeable interlocking concrete paver infiltrates have 50% and 93% samples exceeds standards, respectively. Concentrations of arsenic, iron, potassium, lithium, magnesium, antimony, tin, manganese, and zinc in all permeable pavement infiltrates decreased with time, whereas, aluminum, barium, calcium, chromium and strontium in porous asphalt infiltrates increased. Most metal concentrations in permeable pavement infiltrates either exhibited no significant difference between snow/no-snow seasons or showed statistically larger concentrations

Investigation of negative permeability metamaterials for wireless power transfer

NASA Astrophysics Data System (ADS)

Xin, Wenhui; Mi, Chunting Chris; He, Fei; Jiang, Meng; Hua, Dengxin

2017-11-01

In order to enhance the transmission efficiency of wireless power transfer (WPT), a negative permeability metamaterials (NPM) with a structure of honeycomb composed by units of hexagon-shaped spirals copper is proposed in this paper. The unit parameters of the NPM are optimized, to make sure the negative permeability at the special frequency. The S-parameters of the designed NPM are measured by a network analyzer and the permeability is extracted, it shows the honeycomb NPM has a negative permeability at 6.43 MHz. A two-coil WPT is setup and the transmission efficiency of WPT embedded with NPM at the different position and with different structure are investigated. The measured results show that the 2-slab honeycomb NPM have a good perform compared with the 1-slab NPM, and the efficiency can be increased up to 51%. The results show that honeycomb NPM embedded in the WPT help to improve the transmission efficiency remarkable.

Stress does not increase blood–brain barrier permeability in mice

PubMed Central

Roszkowski, Martin

2016-01-01

Several studies have reported that exposure to acute psychophysiological stressors can lead to an increase in blood–brain barrier permeability, but these findings remain controversial and disputed. We thoroughly examined this issue by assessing the effect of several well-established paradigms of acute stress and chronic stress on blood–brain barrier permeability in several brain areas of adult mice. Using cerebral extraction ratio for the small molecule tracer sodium fluorescein (NaF, 376 Da) as a sensitive measure of blood–brain barrier permeability, we find that neither acute swim nor restraint stress lead to increased cerebral extraction ratio. Daily 6-h restraint stress for 21 days, a model for the severe detrimental impact of chronic stress on brain function, also does not alter cerebral extraction ratio. In contrast, we find that cold forced swim and cold restraint stress both lead to a transient, pronounced decrease of cerebral extraction ratio in hippocampus and cortex, suggesting that body temperature can be an important confounding factor in studies of blood–brain barrier permeability. To additionally assess if stress could change blood–brain barrier permeability for macromolecules, we measured cerebral extraction ratio for fluorescein isothiocyanate-dextran (70 kDa). We find that neither acute restraint nor cold swim stress affected blood–brain barrier permeability for macromolecules, thus corroborating our findings that various stressors do not increase blood–brain barrier permeability. PMID:27146513

Strain-dependent permeability of volcanic rocks.

NASA Astrophysics Data System (ADS)

Farquharson, Jamie; Heap, Michael; Baud, Patrick

2016-04-01

We explore permeability evolution during deformation of volcanic materials using a suite of rocks with varying compositions and physical properties (such as porosity ϕ). 40 mm × 20 mm cylindrical samples were made from a range of extrusive rocks, including andesites from Colima, Mexico (ϕ˜0.08; 0.18; 0.21), Kumamoto, Japan (ϕ˜0.13), and Ruapehu, New Zealand (ϕ˜0.15), and basalt from Mt Etna, Italy (ϕ˜0.04). Gas permeability of each sample was measured before and after triaxial deformation using a steady-state benchtop permeameter. To study the strain-dependence of permeability in volcanic rocks, we deformed samples to 2, 3, 4, 6, and 12 % axial strain at a constant strain rate of 10-5 s-1. Further, the influence of failure mode - dilatant or compactant - on permeability was assessed by repeating experiments at different confining pressures. During triaxial deformation, porosity change of the samples was monitored by a servo-controlled pore fluid pump. Below an initial porosity of ˜0.18, and at low confining pressures (≤ 20 MPa), we observe a dilatant failure mode (shear fracture formation). With increasing axial strain, stress is accommodated by fault sliding and the generation of ash-sized gouge between the fracture planes. In higher-porosity samples, or at relatively higher confining pressures (≥ 60 MPa), we observe compactant deformation characterised by a monotonous decrease in porosity with increasing axial strain. The relative permeability k' is given by the change in permeability divided by the initial reference state. When behaviour is dilatant, k' tends to be positive: permeability increases with progressive deformation. However, results suggest that after a threshold amount of strain, k' can decrease. k' always is negative (permeability decreases during deformation) when compaction is the dominant behaviour. Our results show that - in the absence of a sealing or healing process - the efficiency of a fault to transmit fluids is correlated to

Crustal permeability

USGS Publications Warehouse

Ingebritsen, Steven E.; Gleeson, Tom

2017-01-01

Permeability is the dominant parameter in most hydrogeologic studies. There is abundant evidence for dynamic variations in permeability in time as well as space, and throughout the crust. Whether this dynamic behavior should be included in quantitative models depends on the problem at hand.

Deep permeability of the San Andreas Fault from San Andreas Fault Observatory at Depth (SAFOD) core samples

USGS Publications Warehouse

Morrow, Carolyn A.; Lockner, David A.; Moore, Diane E.; Hickman, Stephen H.

2014-01-01

The San Andreas Fault Observatory at Depth (SAFOD) scientific borehole near Parkfield, California crosses two actively creeping shear zones at a depth of 2.7 km. Core samples retrieved from these active strands consist of a foliated, Mg-clay-rich gouge containing porphyroclasts of serpentinite and sedimentary rock. The adjacent damage zone and country rocks are comprised of variably deformed, fine-grained sandstones, siltstones, and mudstones. We conducted laboratory tests to measure the permeability of representative samples from each structural unit at effective confining pressures, Pe up to the maximum estimated in situ Pe of 120 MPa. Permeability values of intact samples adjacent to the creeping strands ranged from 10−18 to 10−21 m2 at Pe = 10 MPa and decreased with applied confining pressure to 10−20–10−22 m2 at 120 MPa. Values for intact foliated gouge samples (10−21–6 × 10−23 m2 over the same pressure range) were distinctly lower than those for the surrounding rocks due to their fine-grained, clay-rich character. Permeability of both intact and crushed-and-sieved foliated gouge measured during shearing at Pe ≥ 70 MPa ranged from 2 to 4 × 10−22 m2 in the direction perpendicular to shearing and was largely insensitive to shear displacement out to a maximum displacement of 10 mm. The weak, actively-deforming foliated gouge zones have ultra-low permeability, making the active strands of the San Andreas Fault effective barriers to cross-fault fluid flow. The low matrix permeability of the San Andreas Fault creeping zones and adjacent rock combined with observations of abundant fractures in the core over a range of scales suggests that fluid flow outside of the actively-deforming gouge zones is probably fracture dominated.

Darcy Permeability of Hollow Fiber Bundles Used in Blood Oxygenation Devices

PubMed Central

Pacella, Heather E.; Eash, Heidi J.; Federspiel, William J.

2011-01-01

Many industrial and biomedical devices (e.g. blood oxygenators and artificial lungs) use bundles of hollow fiber membranes for separation processes. Analyses of flow and mass transport within the shell-side of the fiber bundles most often model the bundle for simplicity as a packed bed or porous media, using a Darcy permeability coefficient estimated from the Blake-Kozeny equation to account for viscous drag from the fibers. In this study, we developed a simple method for measuring the Darcy permeability of hollow fiber membrane bundles and evaluated how well the Blake-Kozeny (BK) equation predicted the Darcy permeability for these bundles. Fiber bundles were fabricated from commercially available Celgard® ×30-240 fiber fabric (300 μm outer diameter fibers @ 35 and 54 fibers/inch) and from a fiber fabric with 193 μm fibers (61 fibers/inch). The fiber bundles were mounted to the bottom of an acrylic tube and Darcy permeability was determined by measuring the elapsed time for a column of glycerol solution to flow through a fiber bundle. The ratio of the measured Darcy permeability to that predicted from the BK equation varied from 1.09 to 0.56. A comprehensive literature review suggested a modified BK equation with the “constant” correlated to porosity. This modification improved the predictions of the BK equation, with the ratio of measured to predicted permeability varying from 1.13 to 0.84. PMID:22927706

Harmonization in laboratory medicine: Requests, samples, measurements and reports.

PubMed

Plebani, Mario

2016-01-01

In laboratory medicine, the terms "standardization" and "harmonization" are frequently used interchangeably as the final goal is the same: the equivalence of measurement results among different routine measurement procedures over time and space according to defined analytical and clinical quality specifications. However, the terms define two distinct, albeit closely linked, concepts based on traceability principles. The word "standardization" is used when results for a measurement are equivalent and traceable to the International System of Units (SI) through a high-order primary reference material and/or a reference measurement procedure (RMP). "Harmonization" is generally used when results are equivalent, but neither a high-order primary reference material nor a reference measurement procedure is available. Harmonization is a fundamental aspect of quality in laboratory medicine as its ultimate goal is to improve patient outcomes through the provision of accurate and actionable laboratory information. Patients, clinicians and other healthcare professionals assume that clinical laboratory tests performed by different laboratories at different times on the same sample and specimen can be compared, and that results can be reliably and consistently interpreted. Unfortunately, this is not necessarily the case, because many laboratory test results are still highly variable and poorly standardized and harmonized. Although the initial focus was mainly on harmonizing and standardizing analytical processes and methods, the scope of harmonization now also includes all other aspects of the total testing process (TTP), such as terminology and units, report formats, reference intervals and decision limits as well as tests and test profiles, requests and criteria for interpretation. Several projects and initiatives aiming to improve standardization and harmonization in the testing process are now underway. Laboratory professionals should therefore step up their efforts to provide

The influence of pore textures on the permeability of volcanic rocks

NASA Astrophysics Data System (ADS)

Mueller, S.; Spieler, O.; Scheu, B.; Dingwell, D.

2006-12-01

The permeability of a porous medium is strongly dependent on its porosity, as a higher proportion of pore volume is generally expected to lead to a greater probability of pore interconnectedness and the formation of a fluid-flow providing pathway. However, the relationship between permeability and porosity is not a unique one, as many other textural parameters may play an important role and substantially affect gas flow properties. Among these parameters are (a) the connection geometry (i.e. intergranular pore spaces in clastic sediments vs. bubble interconnections), (b) the pore sizes, (c) pore shape and (d) pore size distribution. The gas permeability of volcanic rocks may influence various eruptive processes. The transition from a quiescent degassing dome to rock failure (fragmentation) may, for example, be controlled by the rock's permeability, in as much as it affects the speed by which a gas overpressure in vesicles is reduced in response to decompression. It is therefore essential to understand and quantify influences of different pore textures on the degassing properties of volcanic rocks, as well as investigate the effects of permeability on eruptive processes. Using a modified shock-tube-based fragmentation apparatus, we have measured unsteady-state permeability at a high initial pressure differential. Following sudden decompression above the rock cylinder, pressurized gas flows through the sample in a steel autoclave. A transient 1D filtration code has been developed to calculate permeability using the experimental pressure decay curve within a defined volume below the sample. An external furnace around the autoclave and the use of compressed salt as sealant allows also measurements at high temperatures up to 800 °C. Over 130 permeability measurements have been performed on samples of different volcanic settings, covering a wide range of porosity. The results show a general positive relationship between porosity and permeability with a high data scatter

Transformable ferroelectric control of dynamic magnetic permeability

NASA Astrophysics Data System (ADS)

Jiang, Changjun; Jia, Chenglong; Wang, Fenglong; Zhou, Cai; Xue, Desheng

2018-02-01

Magnetic permeability, which measures the response of a material to an applied magnetic field, is crucial to the performance of magnetic devices and related technologies. Its dynamic value is usually a complex number with real and imaginary parts that describe, respectively, how much magnetic power can be stored and lost in the material. Control of permeability is therefore closely related to energy redistribution within a magnetic system or energy exchange between magnetic and other degrees of freedom via certain spin-dependent interactions. To avoid a high power consumption, direct manipulation of the permeability with an electric field through magnetoelectric coupling leads to high efficiency and simple operation, but remains a big challenge in both the fundamental physics and material science. Here we report unambiguous evidence of ferroelectric control of dynamic magnetic permeability in a Co /Pb (Mg1/3Nb2/3) 0.7Ti0.3O3 (Co/PMN-PT) heterostructure, in which the ferroelectric PMN-PT acts as an energy source for the ferromagnetic Co film via an interfacial linear magnetoelectric interaction. The electric field tuning of the magnitude and line shape of the permeability offers a highly localized means of controlling magnetization with ultralow power consumption. Additionally, the emergence of negative permeability promises a new way of realizing functional nanoscale metamaterials with adjustable refraction index.

Investigation clogging dynamic of permeable pavement systems using embedded sensors

EPA Science Inventory

Permeable pavement is a stormwater control measure commonly selected in both new and retrofit applications. However, there is limited information about the clogging mechanism of these systems that effects the infiltration. A permeable pavement site located at the Seitz Elementary...

Determination of sendust intrinsic permeability from microwave constitutive parameters of composites with sendust spheres and flakes

NASA Astrophysics Data System (ADS)

Starostenko, Sergey N.; Rozanov, Konstantin N.; Shiryaev, Artem O.; Shalygin, Alexander N.; Lagarkov, Andrey N.

2017-06-01

Intrinsic permeability of sendust alloys is determined from the measured microwave permittivity and permeability of composites filled with either spherical or flaky sendust powders. The permittivity and permeability measurements are performed applying the coaxial reflection-transmission technique in the 0.05 to 18 GHz frequency range. The effects of the filling factor, inclusion shape, and size on composite constitutive parameters are discussed. The permeability of metal inclusion is retrieved from the measured permeability of composites using a generalized Maxwell Garnett equation that accounts for the percolation threshold. The equation parameters are found by fitting the measured dependence of composite permittivity and permeability on frequency and filling. The inclusion dimensions calculated from the found parameters agree with the results of grain-size analyses. The alloy intrinsic permeability is retrieved from inclusion permeability with the account for skinning. The fitted frequency and damping factor of ferromagnetic resonance depend on the inclusion shape. The calculated reflectivity map of the flake-filled composite shows that sendust powders are promising fillers for interference suppressors and microwave absorbers at frequencies close to 1 GHz.

Performance of two differently designed permeable reactive barriers with sulfate and zinc solutions.

PubMed

Pérez, Norma; Schwarz, Alex O; Barahona, Esteban; Sanhueza, Pamela; Diaz, Isabel; Urrutia, Homero

2018-06-18

For the first time, this laboratory-scale study evaluates the feasibility of incorporating diffusive exchange in permeable reactive barriers. In order to do this, the performance of two permeable reactive barriers (PRB) with different internal substrate arrangements were compared during the administration of a sulfate solution without metals (for 163 days) and with metals (for 60 days), simulating groundwater contaminated with acid mine drainage (AMD). In order to simulate a traditional PRB, a homogeneous distribution was implemented in the first reactor and the other PRB reactor utilized diffusion-active technology (DAPRB). In the DAPRB, the distribution of the reactive material was interspersed with the conductive material. The measurements in the internal ports showed that transverse gradients of sulfide formed in the DAPRB, causing the diffusion of sulfide from the substrate toward the layer interface, which is where the sulfide reacts by forming complexes with the metal. The DAPRB prevents the microorganisms from direct contact with AMD. This protection caused greater activity (sulfide production). Copyright © 2018 Elsevier B.V. All rights reserved.

Cannabinoids mediate opposing effects on inflammation-induced intestinal permeability

PubMed Central

Alhamoruni, A; Wright, KL; Larvin, M; O'Sullivan, SE

2012-01-01

BACKGROUND AND PURPOSE Activation of cannabinoid receptors decreases emesis, inflammation, gastric acid secretion and intestinal motility. The ability to modulate intestinal permeability in inflammation may be important in therapy aimed at maintaining epithelial barrier integrity. The aim of the present study was to determine whether cannabinoids modulate the increased permeability associated with inflammation in vitro. EXPERIMENTAL APPROACH Confluent Caco-2 cell monolayers were treated for 24 h with IFNγ and TNFα (10 ng·mL−1). Monolayer permeability was measured using transepithelial electrical resistance and flux measurements. Cannabinoids were applied either apically or basolaterally after inflammation was established. Potential mechanisms of action were investigated using antagonists for CB1, CB2, TRPV1, PPARγ and PPARα. A role for the endocannabinoid system was established using inhibitors of the synthesis and degradation of endocannabinoids. KEY RESULTS Δ9-Tetrahydrocannabinol (THC) and cannabidiol accelerated the recovery from cytokine-induced increased permeability; an effect sensitive to CB1 receptor antagonism. Anandamide and 2-arachidonylglycerol further increased permeability in the presence of cytokines; this effect was also sensitive to CB1 antagonism. No role for the CB2 receptor was identified in these studies. Co-application of THC, cannabidiol or a CB1 antagonist with the cytokines ameliorated their effect on permeability. Inhibiting the breakdown of endocannabinoids worsened, whereas inhibiting the synthesis of endocannabinoids attenuated, the increased permeability associated with inflammation. CONCLUSIONS AND IMPLICATIONS These findings suggest that locally produced endocannabinoids, acting via CB1 receptors play a role in mediating changes in permeability with inflammation, and that phytocannabinoids have therapeutic potential for reversing the disordered intestinal permeability associated with inflammation. LINKED ARTICLES This

Iron abundance and magnetic permeability of the moon

NASA Technical Reports Server (NTRS)

Parkin, C. W.; Daily, W. D.; Dyal, P.

1974-01-01

A larger set of simultaneous data from the Apollo 12 lunar surface magnetometer and the Explorer 35 Ames magnetometer are used to construct a whole-moon hysteresis curve, from which a new value of global lunar permeability is determined to be mu = 1.012 + or - 0.006. The corresponding global induced dipole moment is 2.1 times ten to the eighteenth power gauss-cu cm for typical inducing fields of one ten-thousandth gauss in the lunar environment. From the permeability measurement, lunar free iron abundance is determined to be 2.5 + or - 2.0 wt %. Total iron abundance (sum of iron in the ferromagnetic and paramagnetic states) is calculated for two assumed compositional models of the lunar interior: a free iron/orthopyroxene lunar composition and a free iron/olivine composition. The overall lunar total iron abundance is determined to be 9.0 + or - 4.7 wt %. Other lunar models with a small iron core and with a shallow iron-rich layer are discussed in light of the measured global permeability. Effects on permeability and iron content calculations due to a possible lunar ionosphere are also considered.

Solute source depletion control of forward and back diffusion through low-permeability zones.

PubMed

Yang, Minjune; Annable, Michael D; Jawitz, James W

2016-10-01

Solute diffusive exchange between low-permeability aquitards and high-permeability aquifers acts as a significant mediator of long-term contaminant fate. Aquifer contaminants diffuse into aquitards, but as contaminant sources are depleted, aquifer concentrations decline, triggering back diffusion from aquitards. The dynamics of the contaminant source depletion, or the source strength function, controls the timing of the transition of aquitards from sinks to sources. Here, we experimentally evaluate three archetypical transient source depletion models (step-change, linear, and exponential), and we use novel analytical solutions to accurately account for dynamic aquitard-aquifer diffusive transfer. Laboratory diffusion experiments were conducted using a well-controlled flow chamber to assess solute exchange between sand aquifer and kaolinite aquitard layers. Solute concentration profiles in the aquitard were measured in situ using electrical conductivity. Back diffusion was shown to begin earlier and produce larger mass flux for rapidly depleting sources. The analytical models showed very good correspondence with measured aquifer breakthrough curves and aquitard concentration profiles. The modeling approach links source dissolution and back diffusion, enabling assessment of human exposure risk and calculation of the back diffusion initiation time, as well as the resulting plume persistence. Copyright © 2016 Elsevier B.V. All rights reserved.

Fluid flow and coupled poroelastic response in low-permeability rocks

NASA Astrophysics Data System (ADS)

Hasanov, A.; Prasad, M.

2015-12-01

Hydraulic transport properties of reservoir rocks are traditionally defined as rock properties, responsiblefor the passage of fluids through the porous rock sample, as well as their storage. These properties arealso called permeability and storage capacity. The evaluation of both is an important part of any reservoircharacterization workflow. A vivid example of the importance of the transport properties is the bloomingbusiness of unconventional oil and gas production. Tight formations with ultra-low permeabilities and storagecapacities, which have never been perceived as reservoir rocks, today are actively exploited for oil and gas.This tremendous achievement in petroleum science and technology was only possible due to hydraulic frac-turing, which is essentially a process of enhancing permeability and storage capacity by creating a swarmof microcracks in the rock. The knowledge of hydraulic and poroelastic properties is also essential for proper simulations of diffusive pore fluidflow in petroleum reservoirs, as well as aquifers. This work is devoted to an integrated study of low-permeability rocks' hydraulic and poroe-lastic properties as measured with the oscillating pore pressure experiment. The oscillating pore pressuremethod is traditionally used to measure hydraulic transport properties. We modified the method and builtan experimental setup, capable of measuring all aforementioned rock properties simultaneously. The mea-surements were carried out for four sub-millidarcy rock samples at a range of oscillationfrequencies and effective stresses. An apparent frequency dependence of permeability was observed. Measured frequency dispersion of drained poroelastic propertiesindicates an intrinsically inelastic nature of the porous mineral rock frame. Standard Linear Model demon-strated the best fit to the experimental dispersion data. We established that hydraulically-measured storage capacitiesare in good agreement with elastically-derived ones. We also introduce a

Aneurysm permeability following coil embolization: packing density and coil distribution.

PubMed

Chueh, Ju-Yu; Vedantham, Srinivasan; Wakhloo, Ajay K; Carniato, Sarena L; Puri, Ajit S; Bzura, Conrad; Coffin, Spencer; Bogdanov, Alexei A; Gounis, Matthew J

2015-09-01

Rates of durable aneurysm occlusion following coil embolization vary widely, and a better understanding of coil mass mechanics is desired. The goal of this study is to evaluate the impact of packing density and coil uniformity on aneurysm permeability. Aneurysm models were coiled using either Guglielmi detachable coils or Target coils. The permeability was assessed by taking the ratio of microspheres passing through the coil mass to those in the working fluid. Aneurysms containing coil masses were sectioned for image analysis to determine surface area fraction and coil uniformity. All aneurysms were coiled to a packing density of at least 27%. Packing density, surface area fraction of the dome and neck, and uniformity of the dome were significantly correlated (p<0.05). Hence, multivariate principal components-based partial least squares regression models were used to predict permeability. Similar loading vectors were obtained for packing and uniformity measures. Coil mass permeability was modeled better with the inclusion of packing and uniformity measures of the dome (r(2)=0.73) than with packing density alone (r(2)=0.45). The analysis indicates the importance of including a uniformity measure for coil distribution in the dome along with packing measures. A densely packed aneurysm with a high degree of coil mass uniformity will reduce permeability. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Fluid flow simulation and permeability computation in deformed porous carbonate grainstones

NASA Astrophysics Data System (ADS)

Zambrano, Miller; Tondi, Emanuele; Mancini, Lucia; Lanzafame, Gabriele; Trias, F. Xavier; Arzilli, Fabio; Materazzi, Marco; Torrieri, Stefano

2018-05-01

In deformed porous carbonates, the architecture of the pore network may be modified by deformation or diagenetic processes altering the permeability with respect to the pristine rock. The effects of the pore texture and morphology on permeability in porous rocks have been widely investigated due to the importance during the evaluation of geofluid reservoirs. In this study, these effects are assessed by combining synchrotron X-ray computed microtomography (SR micro-CT) and computational fluid dynamics. The studied samples pertain to deformed porous carbonate grainstones highly affected by deformation bands (DBs) exposed in Northwestern Sicily and Abruzzo regions, Italy. The high-resolution SR micro-CT images of the samples, acquired at the SYRMEP beamline of the Elettra - Sincrotrone Trieste laboratory (Italy), were used for simulating a pressure-driven flow by using the lattice-Boltzmann method (LBM). For the experiments, a multiple relaxation time (MRT) model with the D3Q19 scheme was used to avoid viscosity-dependent results of permeability. The permeability was calculated using Darcy's law once steady conditions were reached. After the simulations, the pore-network properties (effective porosity, specific surface area, and geometrical tortuosity) were calculated using 3D images of the velocity fields. These images were segmented considering a velocity threshold value higher than zero. The study showed that DBs may generate significant heterogeneity and anisotropy of the permeability of the evaluated rock samples. Cataclasis and cementation process taking place within the DBs reduce the effective porosity and therefore the permeability. Contrary to this, pressure dissolution and faulting may generate connected channels which contribute to the permeability only parallel to the DB.

Laboratory Measurements of Celestial Solids

NASA Technical Reports Server (NTRS)

Sievers, A. J.; Beckwith, S. V. W.

1997-01-01

Our experimental study has focused on laboratory measurements of the low temperature optical properties of a variety of astronomically significant materials in the infrared and mm-wave region of the spectrum. Our far infrared measurements of silicate grains with an open structure have produced a variety of unusual results: (1) the low temperature mass opacity coefficient of small amorphous 2MgO(central dot)SiO2 and MgO(central dot)2SiO2 grains are many times larger than the values previously used for interstellar grain material; (2) all of the amorphous silicate grains studied possess the characteristic temperature dependent signature associated with two level systems in bulk glass; and (3) a smaller but nonzero two level temperature dependence signature is also observed for crystalline particles, its physical origin is unclear. These laboratory measurements yield surprisingly large and variable values for the mm-wave absorption coefficients of small silicate particles similar to interstellar grains, and suggest that the bulk absorptivity of interstellar dust at these long wavelengths will not be well known without such studies. Furthermore, our studies have been useful to better understand the physics of the two level absorption process in amorphous and crystalline grains to gain confidence in the wide applicability of these results.

Estimation of relative permeability and capillary pressure from mass imbibition experiments

NASA Astrophysics Data System (ADS)

Alyafei, Nayef; Blunt, Martin J.

2018-05-01

We perform spontaneous imbibition experiments on three carbonates - Estaillades, Ketton, and Portland - which are three quarry limestones that have very different pore structures and span wide range of permeability. We measure the mass of water imbibed in air saturated cores as a function of time under strongly water-wet conditions. Specifically, we perform co-current spontaneous experiments using a highly sensitive balance to measure the mass imbibed as a function of time for the three rocks. We use cores measuring 37 mm in diameter and three lengths of approximately 76 mm, 204 mm, and 290 mm. We show that the amount imbibed scales as the square root of time and find the parameter C, where the volume imbibed per unit cross-sectional area at time t is Ct1/2. We find higher C values for higher permeability rocks. Employing semi-analytical solutions for one-dimensional flow and using reasonable estimates of relative permeability and capillary pressure, we can match the experimental data. We finally discuss how, in combination with conventional measurements, we can use theoretical solutions and imbibition measurements to find or constrain relative permeability and capillary pressure.

SINGLE-INTERVAL GAS PERMEABILITY ESTIMATION

EPA Science Inventory

Single-interval, steady-steady-state gas permeability testing requires estimation of pressure at a screened interval which in turn requires measurement of friction factors as a function of mass flow rate. Friction factors can be obtained by injecting air through a length of pipe...

Scaffold permeability as a means to determine fiber diameter and pore size of electrospun fibrinogen.

PubMed

Sell, Scott; Barnes, Catherine; Simpson, David; Bowlin, Gary

2008-04-01

The purpose of this study was to construct a flowmeter that could accurately measure the hydraulic permeability of electrospun fibrinogen scaffolds, providing insight into the transport properties of electrospun scaffolds while making the measurement of their topographical features (fiber diameter and pore size) more accurate. Three different concentrations of fibrinogen were used (100, 120, and 150 mg/mL) to create scaffolds with three different fiber diameters and pore sizes. The fiber diameters and pore sizes of the electrospun scaffolds were first analyzed with scanning electron microscopy and image analysis software. The permeability of each scaffold was measured with the flowmeter and used to calculate permeability-based fiber diameters and pore sizes, which were compared to values obtained through image analysis. Permeability measurement revealed scaffold permeability to increase with fibrinogen concentration, much like average fiber diameter and pore size. Comparison between the two measurement methods demonstrated the efficacy of the flowmeter as a way to measure scaffold features. Copyright 2007 Wiley Periodicals, Inc.

Permeability Testing of Impacted Composite Laminates for Use on Reusable Launch Vehicles

NASA Technical Reports Server (NTRS)

Nettles, A. T.

2001-01-01

Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite, and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented, and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a nonlinear fashion for almost all the specimens tested.

Laboratory ginning and blending impacts on cotton fiber micronaire measurements

USDA-ARS?s Scientific Manuscript database

Micronaire, a critical cotton quality parameter, is normally measured in a conditioned laboratory, but increasing interest has been shown in new technologies that can measure micronaire both in and outside of the laboratory. Near Infrared (NIR) technology has demonstrated its ability to measure cot...

Borehole measurement of the hydraulic properties of low-permeability rock

NASA Astrophysics Data System (ADS)

Novakowski, Kentner S.; Bickerton, Gregory S.

1997-11-01

Hydraulic tests conducted in low-permeability media are subject to numerous influences and processes, many of which manifest in a nonunique fashion. To explore the accuracy and meaning of the interpretation of hydraulic tests conducted under such conditions, two semianalytical models are developed in which variable well bore storage, variable temperature, and test method are considered. The formation is assumed to be of uniform permeability and uniform storativity in both models. To investigate uncertainty in the use of these models, a comparison is conducted to similar models that account for nonuniform formation properties such as finite skin, double porosity, and fractional flow. Using the models for a finite skin and double porosity as baseline cases, results show that the interpretation of slug tests are normally nonunique when tests are conducted in material of low permeability. Provided that a lower bound is defined for storativity, the uncertainty in a given interpretation conducted with the model for a uniform medium can be established by comparison with a fit to the data obtained using the model incorporating finite skin. It was also found that the degree of uncertainty can be diminished by conducting the test using an open hole period followed by a shut-in period (similar to a drill stem test). Determination of the degree of uncertainty was found to be case specific and must be defined by using at least a comparison between the model for uniform media and that for finite skin. To illustrate the use of the slug test model and determine the degree of uncertainty that will accrue with the use of that model, a field example, potentially influenced by variable well bore storage, is presented and interpreted.

Petrophysics of low-permeability medina sandstone, northwestern Pennsylvania, Appalachian Basin

USGS Publications Warehouse

Castle, J.W.; Byrnes, A.P.

1998-01-01

Petrophysical core testing combined with geophysical log analysis of low-permeability, Lower Silurian sandstones of the Appalachian basin provides guidelines and equations for predicting gas producibility. Permeability values are predictable from the borehole logs by applying empirically derived equations based on correlation between in-situ porosity and in-situ effective gas permeability. An Archie-form equation provides reasonable accuracy of log-derived water saturations because of saturated brine salinities and low clay content in the sands. Although measured porosity and permeability average less than 6% and 0.1 mD, infrequent values as high as 18% and 1,048 mD occur. Values of effective gas permeability at irreducible water saturation (Swi) range from 60% to 99% of routine values for the highest permeability rocks to several orders of magnitude less for the lowest permeability rocks. Sandstones having porosity greater than 6% and effective gas permeability greater than 0.01 mD exhibit Swi less than 20%. With decreasing porosity, Swi sharply increases to values near 40% at 3 porosity%. Analysis of cumulative storage and flow capacity indicates zones with porosity greater than 6% generally contain over 90% of flow capacity and hold a major portion of storage capacity. For rocks with Swi < 20%, gas relative permeabilities exceed 45%. Gas relative permeability and hydrocarbon volume decrease rapidly with increasing Swi as porosity drops below 6%. At Swi above 40%, gas relative permeabilities are less than approximately 10%.

Perm-Fit: a new program to estimate permeability at high P-T conditions

NASA Astrophysics Data System (ADS)

Moulas, Evangelos; Madonna, Claudio

2016-04-01

Several geological processes are controlled by porous fluid flow. The circulation of porous fluids influences many physical phenomena and in turn it depends on the rock permeability. The permeability of rocks is a physical property that needs to be measured since it depends on many factors such as secondary porosity (fractures etc). We present a numerical approach to estimate permeability using the transient step method (Brace et al., 1968). When a non-reacting, compressible fluid is considered in a relative incompressible solid matrix, the only unknown parameter in the equations of porous flow is permeability. Porosity is assumed to be known and the physical properties of the fluid (compressibility, density, viscosity) are taken from the NIST database. Forward numerical calculations for different values of permeability are used and the results are compared to experimental measurements. The extracted permeability value is the one that minimizes the misfit between experimental and numerical results. The uncertainty on the value of permeability is estimated using a Monte Carlo method. REFERENCES Brace, W.F., Walsh J.B., & Frangos, W.T. 1968: Permeability of Granite under High Pressure, Journal of Geophysical Research, 73, 6, 2225-2236

Support vector regression to predict porosity and permeability: Effect of sample size

NASA Astrophysics Data System (ADS)

Al-Anazi, A. F.; Gates, I. D.

2012-02-01

Porosity and permeability are key petrophysical parameters obtained from laboratory core analysis. Cores, obtained from drilled wells, are often few in number for most oil and gas fields. Porosity and permeability correlations based on conventional techniques such as linear regression or neural networks trained with core and geophysical logs suffer poor generalization to wells with only geophysical logs. The generalization problem of correlation models often becomes pronounced when the training sample size is small. This is attributed to the underlying assumption that conventional techniques employing the empirical risk minimization (ERM) inductive principle converge asymptotically to the true risk values as the number of samples increases. In small sample size estimation problems, the available training samples must span the complexity of the parameter space so that the model is able both to match the available training samples reasonably well and to generalize to new data. This is achieved using the structural risk minimization (SRM) inductive principle by matching the capability of the model to the available training data. One method that uses SRM is support vector regression (SVR) network. In this research, the capability of SVR to predict porosity and permeability in a heterogeneous sandstone reservoir under the effect of small sample size is evaluated. Particularly, the impact of Vapnik's ɛ-insensitivity loss function and least-modulus loss function on generalization performance was empirically investigated. The results are compared to the multilayer perception (MLP) neural network, a widely used regression method, which operates under the ERM principle. The mean square error and correlation coefficients were used to measure the quality of predictions. The results demonstrate that SVR yields consistently better predictions of the porosity and permeability with small sample size than the MLP method. Also, the performance of SVR depends on both kernel function

Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - II. Microstructures and their implications for permeability and strength

USGS Publications Warehouse

Moore, Diane E.; Lockner, D.A.; Ito, H.; Ikeda, R.; Tanaka, H.; Omura, K.

2009-01-01

Samples of damage-zone granodiorite and fault core from two drillholes into the active, strike-slip Nojima fault zone display microstructures and alteration features that explain their measured present-day strengths and permeabilities and provide insight on the evolution of these properties in the fault zone. The least deformed damage-zone rocks contain two sets of nearly perpendicular (60-90?? angles), roughly vertical fractures that are concentrated in quartz-rich areas, with one set typically dominating over the other. With increasing intensity of deformation, which corresponds generally to increasing proximity to the core, zones of heavily fragmented rock, termed microbreccia zones, develop between prominent fractures of both sets. Granodiorite adjoining intersecting microbreccia zones in the active fault strands has been repeatedly fractured and locally brecciated, accompanied by the generation of millimeter-scale voids that are partly filled with secondary minerals. Minor shear bands overprint some of the heavily deformed areas, and small-scale shear zones form from the pairing of closely spaced shear bands. Strength and permeability measurements were made on core collected from the fault within a year after a major (Kobe) earthquake. Measured strengths of the samples decrease regularly with increasing fracturing and fragmentation, such that the gouge of the fault core and completely brecciated samples from the damage zone are the weakest. Permeability increases with increasing disruption, generally reaching a peak in heavily fractured but still more or less cohesive rock at the scale of the laboratory samples. Complete loss of cohesion, as in the gouge or the interiors of large microbreccia zones, is accompanied by a reduction of permeability by 1-2 orders of magnitude below the peak values. The core samples show abundant evidence of hydrothermal alteration and mineral precipitation. Permeability is thus expected to decrease and strength to increase somewhat

Passive flux meter measurement of water and nutrient flux in saturated porous media: bench-scale laboratory tests.

PubMed

Cho, Jaehyun; Annable, Michael D; Jawitz, James W; Hatfield, Kirk

2007-01-01

The passive nutrient flux meter (PNFM) is introduced for simultaneous measurement of both water and nutrient flux through saturated porous media. The PNFM comprises a porous sorbent pre-equilibrated with a suite of alcohol tracers, which have different partitioning coefficients. Water flux was estimated based on the loss of loaded resident tracers during deployment, while nutrient flux was quantified based on the nutrient solute mass captured on the sorbent. An anionic resin, Lewatit 6328 A, was used as a permeable sorbent and phosphate (PO4(3-)) was the nutrient studied. The phosphate sorption capacity of the resin was measured in batch equilibration tests as 56 mg PO4(3-) g(-1), which was determined to be adequate capacity to retain PO4(3-) loads intercepted over typical PNFM deployment periods in most natural systems. The PNFM design was validated with bench-scale laboratory tests for a range of 9.8 to 28.3 cm d(-1) Darcy velocities and 6 to 43 h deployment durations. Nutrient and water fluxes measured by the PNFM averaged within 6 and 12% of the applied values, respectively, indicating that the PNFM shows promise as a tool for simultaneous measurement of water and nutrient fluxes.

Permeability of volcanic rocks to gas and water

NASA Astrophysics Data System (ADS)

Heap, M. J.; Reuschlé, T.; Farquharson, J. I.; Baud, P.

2018-04-01

The phase (gas or liquid) of the fluids within a porous volcanic system varies in both time and space. Laboratory experiments have shown that gas and water permeabilities can differ for the same rock sample, but experiments are biased towards rocks that contain minerals that are expected react with the pore fluid (such as the reaction between liquid water and clay). We present here the first study that systematically compares the gas and water permeability of volcanic rocks. Our data show that permeabilities to argon gas and deionised water can differ by a factor between two and five in two volcanic rocks (basalt and andesite) over a confining pressure range from 2 to 50 MPa. We suggest here that the microstructural elements that offer the shortest route through the sample-estimated to have an average radius 0.1-0.5 μm using the Klinkenberg slip factor-are accessible to gas, but restricted or inaccessible to water. We speculate that water adsorption on the surface of these thin microstructural elements, assumed here to be tortuous/rough microcracks, reduces their effective radius and/or prevents access. These data have important implications for fluid flow and therefore the distribution and build-up of pore pressure within volcanic systems.

On the Examination of Darcy Permeability a Thin Fibrous Porous Layer

NASA Astrophysics Data System (ADS)

Zhu, Zenghao; Wang, Qiuyun; Wu, Qianhong; Vucbmss Team

2016-11-01

In this paper, we report a novel experimental approach to investigate the Darcy permeability of a soft and thin fibrous porous layer. The project is inspired by recent studies involved compression of very thin porous films and the resultant pore fluid flow inside the confined porous structure. The Darcy permeability plays a critical role during the process, which however, is tricky to measure due to the very thin nature of the porous media. In the current study, a special micro-fluidic device is developed that consists of a rectangular flow channel with adjustable gap height ranging from 20 mm to 0.5 mm. Air is forced through the thin gap filled with testing fibrous materials. By measuring the flow rate and the pressure drop, we have successfully obtained the Darcy permeability of different thin porous sheets at different compression ratios. Furthermore, the surface area of the fibers are evaluated using a Micromeritics® ASAP 2020 (Accelerated Surface Area and Porosimetry) system. We found that, although the functions relating the permeability and porosities are different for different fibrous materials, these functions collapse to a single relationship if one express the permeability as a function of the solid phase surface area per unit volume. This finding provides a useful approach to evaluate the permeability of very thin fibrous porous sheet, which otherwise is difficult to measure directly. This research was supported by the National Science Foundation under Award #1511096.

Influence of capillary end effects on steady-state relative permeability estimates from direct pore-scale simulations

NASA Astrophysics Data System (ADS)

Guédon, Gaël Raymond; Hyman, Jeffrey De'Haven; Inzoli, Fabio; Riva, Monica; Guadagnini, Alberto

2017-12-01

We investigate and characterize the influence of capillary end effects on steady-state relative permeabilities obtained in pore-scale numerical simulations of two-phase flows. Our study is motivated by the observation that capillary end effects documented in two-phase laboratory-scale experiments can significantly influence permeability estimates. While numerical simulations of two-phase flows in reconstructed pore-spaces are increasingly employed to characterize relative permeabilities, a phenomenon which is akin to capillary end effects can also arise in such analyses due to the constraints applied at the boundaries of the computational domain. We profile the relative strength of these capillary end effects on the calculation of steady-state relative permeabilities obtained within randomly generated porous micro-structures using a finite volume-based two-phase flow solver. We suggest a procedure to estimate the extent of the regions influenced by these capillary end effects, which in turn allows for the alleviation of bias in the estimation of relative permeabilities.

Extension of laboratory-measured soil spectra to field conditions

NASA Technical Reports Server (NTRS)

Stoner, E. R.; Baumgardner, M. F.; Weismiller, R. A.; Biehl, L. L.; Robinson, B. F.

1982-01-01

Spectral responses of two glaciated soils, Chalmers silty clay loam and Fincastle silt loam, formed under prairie grass and forest vegetation, respectively, were measured in the laboratory under controlled moisture equilibria using an Exotech Model 20C spectroradiometer to obtain spectral data in the laboratory under artificial illumination. The same spectroradiometer was used outdoors under solar illumination to obtain spectral response from dry and moistened field plots with and without corn residue cover, representing the two different soils. Results indicate that laboratory-measured spectra of moist soil are directly proportional to the spectral response of that same field-measured moist bare soil over the 0.52 micrometer to 1.75 micrometer wavelength range. The magnitudes of difference in spectral response between identically treated Chalmers and Fincastle soils are greatest in the 0.6 micrometers to 0.8 micrometer transition region between the visible and near infrared, regardless of field condition or laboratory preparation studied.

Study of permeability characteristics of membranes

NASA Technical Reports Server (NTRS)

Spiegler, K. S.; Messalem, R. M.; Moore, R. J.; Leibovitz, J.

1971-01-01

Pressure-permeation experiments were performed with the concentration-clamp cell. Streaming potentials and hydraulic permeabilities were measured for an AMF C-103 cation-exchange membrane bounded by 0.1 N NaCl solutions. The streaming potential calculated from the slope of the recorded potential differences versus the applied pressure, yields a value of 1.895 millivolt/dekabar. When comparison with other membranes of similar characteristics could be made, good agreement was found. The values of the hydraulic permeability varied somewhat with the applied pressure difference and are between 1.3 x 10 to the minus 8th power and 3.9 x 10 to the minus 8th power sq cm/dekabar-sec. The specific hydraulic permeabilities were also calculated and compared with data from the literature. Fair agreement was found. The diffusion coefficient of the chloride ion in the AMF C-103 membrane was calculated, using Fick's first law of diffusion based on ion concentrations calculated from the Donnan equilibrium concentration of Cl(-).

Quantifying Evaporation and Evaluating Runoff Estimation Methods in a Permeable Pavement System - abstract

EPA Science Inventory

Studies on quantifying evaporation in permeable pavement systems are limited to few laboratory studies that used a scale to weigh evaporative losses and a field application with a tunnel-evaporation gauge. A primary objective of this research was to quantify evaporation for a la...

Effects of Aspirin on Gastroduodenal Permeability in Alcoholics and Controls

PubMed Central

Farhadi, Ashkan; Keshavarzian, Ali; Kwasny, Mary J.; Shaikh, Maliha; Fogg, Louis; Lau, Cynthia; Fields, Jeremy Z.; Forsyth, Christopher B.

2010-01-01

Alcohol and non-steroidal anti-inflammatory drugs (NSAIDS) are noxious agents that can disrupt the integrity of the gastroduodenal mucosal and damage the epithelial barrier, and lead to increased gastroduodenal permeability. Moreover, it is not uncommon that patients are exposed to these two barrier stressors at the same time. It is thus important to know how simultaneous exposure affects the gastroduodenal barrier, and acquiring that knowledge was the goal of this study. We used a method that has been widely used for the assessment of injury to the gastroduodenal barrier induced by these noxious agents – measurement of gastroduodenal permeability as indicated by urinary excretion of ingested sucrose. We used gas chromatography to measure the amount of sucrose excreted in the urine over the 5–12 h following ingestion of a bolus of sucrose. The 148 participants in the study included 92 alcoholics and 56 healthy controls. All study subjects had a baseline permeability test. To determine whether addition of a second noxious agent, in addition to chronic alcohol, further decreases gastroduodenal barrier integrity, a subset of 118 study subjects participated in another permeability test in which they were exposed to aspirin. For this test, participants ingested 1300 mg aspirin twice, 12 hours and 1 hour before the final permeability test. The baseline permeability test showed that alcoholics have significantly higher gastroduodenal permeability than controls. Aspirin caused a significant within group absolute increase in gastroduodenal permeability in both alcoholics and controls (+7.72%, p=0.003 and +2.25%, p = 0.011, respectively) but the magnitude of these increases were not significantly different from each other. Baseline permeability did vary by gender, self-reported illegal drug use, and employment type. The extent of the permeability increase after aspirin ingestion varied with illegal drug use and recruitment site (a surrogate marker of socioeconomic status

Safety in the Chemical Laboratory: Laboratory Air Quality: Part II. Measurements of Ventilation Rates.

ERIC Educational Resources Information Center

Butcher, Samuel S.; And Others

1985-01-01

Part I of this paper (SE 538 295) described a simple model for estimating laboratory concentrations of gas phase pollutants. In this part, the measurement of ventilation rates and applications of the model are discussed. The model can provide a useful starting point in planning for safer instructional laboratories. (JN)

Demonstrations of Magnetic Phenomena: Measuring the Air Permeability Using Tablets

ERIC Educational Resources Information Center

Lara, V. O. M.; Amaral, D. F.; Faria, D.; Vieira, L. P.

2014-01-01

We use a tablet to experimentally determine the dependencies of the magnetic field (B) on the electrical current and the axial distance from a coil (z). Our data shows good precision on the inverse cubic dependence of the magnetic field on the axial distance, B?z[superscript -3]. We obtain the value of air permeability µ[subscript air] with good…

Implementation of an automated test setup for measuring electrical conductance of concrete.

DOT National Transportation Integrated Search

2007-01-01

This project was designed to provide the Virginia Department of Transportation (VDOT) with an automated laboratory setup for performing the rapid chloride permeability test (RCPT) to measure the electrical conductance of concrete in accordance with a...

Measuring meaningful learning in the undergraduate chemistry laboratory

NASA Astrophysics Data System (ADS)

Galloway, Kelli R.

The undergraduate chemistry laboratory has been an essential component in chemistry education for over a century. The literature includes reports on investigations of singular aspects laboratory learning and attempts to measure the efficacy of reformed laboratory curriculum as well as faculty goals for laboratory learning which found common goals among instructors for students to learn laboratory skills, techniques, experimental design, and to develop critical thinking skills. These findings are important for improving teaching and learning in the undergraduate chemistry laboratory, but research is needed to connect the faculty goals to student perceptions. This study was designed to explore students' ideas about learning in the undergraduate chemistry laboratory. Novak's Theory of Meaningful Learning was used as a guide for the data collection and analysis choices for this research. Novak's theory states that in order for meaningful learning to occur the cognitive, affective, and psychomotor domains must be integrated. The psychomotor domain is inherent in the chemistry laboratory, but the extent to which the cognitive and affective domains are integrated is unknown. For meaningful learning to occur in the laboratory, students must actively integrate both the cognitive domain and the affective domains into the "doing" of their laboratory work. The Meaningful Learning in the Laboratory Instrument (MLLI) was designed to measure students' cognitive and affective expectations and experiences within the context of conducting experiments in the undergraduate chemistry laboratory. Evidence for the validity and reliability of the data generated by the MLLI were collected from multiple quantitative studies: a one semester study at one university, a one semester study at 15 colleges and universities across the United States, and a longitudinal study where the MLLI was administered 6 times during two years of general and organic chemistry laboratory courses. Results from

The Permeability of the Sodium Channel to Metal Cations in Myelinated Nerve

PubMed Central

Hille, Bertil

1972-01-01

The relative permeability of sodium channels to eight metal cations is studied in myelinated nerve fibers. Ionic currents under voltage-clamp conditions are measured in Na-free solutions containing the test ion. Measured reversal potentials and the Goldman equation are used to calculate the permeability sequence: Na+ ≈ Li+ > Tl+ > K+. The ratio P K/P Na is 1/12. The permeabilities to Rb+, Cs+, Ca++, and Mg++ are too small to measure. The permeability ratios agree with observations on the squid giant axon and show that the reversal potential E Na differs significantly from the Nernst potential for Na+ in normal axons. Opening and closing rates for sodium channels are relatively insensitive to the ionic composition of the bathing medium, implying that gating is a structural property of the channel rather than a result of the movement or accumulation of particular ions around the channel. A previously proposed pore model of the channel accommodates the permeant metal cations in a partly hydrated form. The observed sequence of permeabilities follows the order expected for binding to a high field strength anion in Eisenman's theory of ion exchange equilibria. PMID:5025743

Heavy Cigarette Smokers in a Chinese Population Display a Compromised Permeability Barrier

PubMed Central

Xin, Shujun; Ye, Li; Lv, Chengzhi; Elias, Peter M.

2016-01-01

Cigarette smoking is associated with various cutaneous disorders with defective permeability. Yet, whether cigarette smoking influences epidermal permeability barrier function is largely unknown. Here, we measured skin biophysical properties, including permeability barrier homeostasis, stratum corneum (SC) integrity, SC hydration, skin surface pH, and skin melanin/erythema index, in cigarette smokers. A total of 99 male volunteers were enrolled in this study. Smokers were categorized as light-to-moderate (<20 cigarettes/day) or heavy smokers (≥20 cigarettes/day). An MPA5 was used to measure SC hydration and skin melanin/erythema index on the dorsal hand, forehead, and cheek. Basal transepidermal water loss (TEWL) and barrier recovery rates were assessed on the forearm. A Skin-pH-Meter pH900 was used to measure skin surface pH. Our results showed that heavy cigarette smokers exhibited delayed barrier recovery after acute abrogation (1.02% ± 13.06 versus 16.48% ± 6.07), and barrier recovery rates correlated negatively with the number of daily cigarettes consumption (p = 0.0087). Changes in biophysical parameters in cigarette smokers varied with body sites. In conclusion, heavy cigarette smokers display compromised permeability barrier homeostasis, which could contribute, in part, to the increased prevalence of certain cutaneous disorders characterized by defective permeability. Thus, improving epidermal permeability barrier should be considered for heavy cigarette smokers. PMID:27437403

Duration of ultrasound-mediated enhanced plasma membrane permeability.

PubMed

Lammertink, Bart; Deckers, Roel; Storm, Gert; Moonen, Chrit; Bos, Clemens

2015-03-30

Ultrasound (US) induced cavitation can be used to enhance the intracellular delivery of drugs by transiently increasing the cell membrane permeability. The duration of this increased permeability, termed temporal window, has not been fully elucidated. In this study, the temporal window was investigated systematically using an endothelial- and two breast cancer cell lines. Model drug uptake was measured as a function of time after sonication, in the presence of SonoVue™ microbubbles, in HUVEC, MDA-MB-468 and 4T1 cells. In addition, US pressure amplitude was varied in MDA-MB-468 cells to investigate its effect on the temporal window. Cell membrane permeability of HUVEC and MDA-MB-468 cells returned to control level within 1-2 h post-sonication, while 4T1 cells needed over 3h. US pressure affected the number of cells with increased membrane permeability, as well as the temporal window in MDA-MB-468 cells. This study shows that the duration of increased membrane permeability differed between the cell lines and US pressures used here. However, all were consistently in the order of 1-3 h after sonication. Copyright © 2014 Elsevier B.V. All rights reserved.

Inferring Firn Permeability from Pneumatic Testing: A Case Study on the Greenland Ice Sheet

NASA Astrophysics Data System (ADS)

Sommers, Aleah N.; Rajaram, Harihar; Weber, Eliezer P.; MacFerrin, Michael J.; Colgan, William T.; Stevens, C. Max

2017-03-01

Across the accumulation zone of the Greenland ice sheet, summer temperatures can be sufficiently warm to cause widespread melting, as was the case in July 2012 when the entire ice sheet experienced a brief episode of enhanced surface ablation. The resulting meltwater percolates into the firn and refreezes, to create ice lenses and layers within the firn column. This is an important process to consider when estimating the surface mass balance of the ice sheet. The rate of meltwater percolation depends on the permeability of the firn, a property that is not well constrained in the presence of refrozen ice layers and lenses. We present a novel, inexpensive method for measuring in-situ firn permeability using pneumatic testing, a well-established technique used in environmental engineering and hydrology. To illustrate the capabilities of this method, we estimate both horizontal and vertical permeability from pilot tests at six sites on the Greenland ice sheet: KAN-U, DYE-2, EKT, NASA-SE, Saddle, and EastGRIP. These sites cover a range of conditions from mostly dry firn (EastGRIP), to firn with several ice layers and lenses from refrozen meltwater (Saddle, NASA-SE, EKT), to firn with extensive ice layers (DYE-2 and KAN-U). The estimated permeability in firn without refrozen ice layers at EastGRIP agrees well with the range previously reported using an air permeameter to measure permeability through firn core samples at Summit, Greenland. At sites with ice lenses or layers, we find high degrees of anisotropy, with vertical permeability much lower than horizontal permeability. Pneumatic testing is a promising and low-cost technique for measuring firn permeability, particularly as meltwater production increases in the accumulation zone and ice layers and lenses from refrozen melt layers become more prevalent. In these initial proof-of-concept tests, the estimated permeabilities represent effective permeability at the meter scale. With appropriately higher vacuum pressures

Permeability anisotropy of serpentinite and fluid pathways in a subduction zone

NASA Astrophysics Data System (ADS)

Katayama, I.; Kawano, S.; Okazaki, K.

2011-12-01

Subduction zones are the only sites where water is transported into the Earth's deep interior. Although the fluid released into the mantle wedge is generally believed to ascend under buoyancy, it is possible that fluid movement is influenced by anisotropic permeability in localized shear zones. The mantle rocks at the plate interface of a subducting slab are subjected to non-coaxial stress and commonly develop a strong foliation. Indeed, the existence of foliated serpentinite is indicated by strong seismic anisotropy in the forearc mantle wedge (e.g., Katayama et al., 2009; Bezacier et al., 2010). Therefore, fluid pathways in the mantle wedge may be controlled by the preferred orientation of highly anisotropic minerals. In this study, we measured the permeability of highly foliated natural serpentinite, in directions parallel and perpendicular to the foliation, and we discuss the influence of permeability anisotropy on fluid flow in subduction zones. The permeability was measured by an intra-vessel deformation and fluid flow apparatus housed at Hiroshima University. In the measurements, we used nitrogen gas as a pore fluid and maintained constant pore pressure during the measurements (Pp < 6 MPa). The obtained gas permeability was then converted to intrinsic permeability using the Klinkenberg effect, which is known to be insensitive to the type of pore fluid. Under low confining pressure, all the experiments show similar permeability, in the order of 10-19 m2. However, permeability anisotropy appears under high confining pressures, with the specimens oriented parallel to the foliation having higher permeability than those oriented normal to the foliation. At a confining pressure of 50 MPa, the difference in permeability between the samples with contrasting orientations reaches several orders of magnitude, possibly reflecting the pore tortuosity of the highly sheared serpentinite, as indicated by the Kozeny-Carman relation. The present experimental data show that

Continuous Record of Permeability inside the Wenchuan Earthquake Fault Zone

NASA Astrophysics Data System (ADS)

Xue, Lian; Li, Haibing; Brodsky, Emily

2013-04-01

Faults are complex hydrogeological structures which include a highly permeable damage zone with fracture-dominated permeability. Since fractures are generated by earthquakes, we would expect that in the aftermath of a large earthquake, the permeability would be transiently high in a fault zone. Over time, the permeability may recover due to a combination of chemical and mechanical processes. However, the in situ fault zone hydrological properties are difficult to measure and have never been directly constrained on a fault zone immediately after a large earthquake. In this work, we use water level response to solid Earth tides to constrain the hydraulic properties inside the Wenchuan Earthquake Fault Zone. The transmissivity and storage determine the phase and amplitude response of the water level to the tidal loading. By measuring phase and amplitude response, we can constrain the average hydraulic properties of the damage zone at 800-1200 m below the surface (~200-600 m from the principal slip zone). We use Markov chain Monte Carlo methods to evaluate the phase and amplitude responses and the corresponding errors for the largest semidiurnal Earth tide M2 in the time domain. The average phase lag is ~ 30o, and the average amplitude response is 6×10-7 strain/m. Assuming an isotropic, homogenous and laterally extensive aquifer, the average storage coefficient S is 2×10-4 and the average transmissivity T is 6×10-7 m2 using the measured phase and the amplitude response. Calculation for the hydraulic diffusivity D with D=T/S, yields the reported value of D is 3×10-3 m2/s, which is two orders of magnitude larger than pump test values on the Chelungpu Fault which is the site of the Mw 7.6 Chi-Chi earthquake. If the value is representative of the fault zone, then this means the hydrology processes should have an effect on the earthquake rupture process. This measurement is done through continuous monitoring and we could track the evolution for hydraulic properties

Effect of age on pulmonary epithelial permeability in unanesthetized lambs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hutchison, A.A.; McNicol, K.J.; Loughlin, G.M.

1985-01-01

Pulmonary epithelial permeability was measured 1) in unanesthetized sheep, and 2) longitudinally in growing lambs. Awake sheep were intubated and a solution of /sup 51/Cr-ethylenediaminetetraacetic acid and /sup 125/I-antipyrine was instilled in the intrathoracic trachea via the nasotracheal tube. Arterial blood was drawn 1-25 minutes after the instillation. The ratios of the counts of /sup 51/Cr to /sup 125/I at 7, 10, and 13 min were calculated and averaged for each animal. Data from six adult sheep showed that the mean +/- SE of the permeability ratio was 0.012 +/- 0.003 and was reproducible over three months. When measured twicemore » within two hours, the second ratio was significantly higher than the first. One hour of general anesthesia with methoxyflurane did not alter the permeability ratio significantly. Ten lambs were studied longitudinally 10 hours and 5, 10, 20, and 30 days after delivery. Within the first 24 hours of life the permeability ratio was, significantly greater than the adult value. At five days there was no significant difference between lambs and adult sheep. Throughout the first month of life, the permeability ratio in lambs remained at at the adult level.« less

Effect of desensitizing agents on dentin permeability.

PubMed

Ishihata, Hiroshi; Kanehira, Masafumi; Nagai, Tomoko; Finger, Werner J; Shimauchi, Hidetoshi; Komatsu, Masashi

2009-06-01

To investigate the in vitro efficacy of two dentin desensitizing products at reducing liquid permeability through human dentin discs. The tested hypothesis was that the products, in spite of different chemical mechanisms were not different at reducing or eliminating flow through dentin discs. Dentin slices (1 mm thick) were prepared from 16 extracted human third molars and their permeability was indirectly recorded in a split chamber model, using a chemiluminescence technique, after EDTA treatment (control), after soaking with albumin, and after desensitizer application. Two products were studied: MS Coat, a self-curing resin-containing oxalate product, and Gluma Desensitizer, a glutaraldehyde/HEMA-based agent without initiator. The dentin slices were mounted between an upper chamber, filled with an aqueous solution of 1% potassium ferricyanide and 0.3% hydrogen peroxide, and a lower chamber filled with 1% sodium hydroxide solution and 0.02% luminol. The upper solution was pressurized, and upon contact with the luminol solution a photochemical signal was generated and recorded as a measure of permeability throughout two consecutive pressurizing cycles at 2.5 and 13 kPa (26 and 133 cm H2O), respectively. The permeability of the control and albumin-soaked samples was similarly high. After application of the desensitizing agents, dentin permeability was reduced to virtually zero at both pressure levels (P < 0.001).

Insights into reptile dermal contaminant exposure: Reptile skin permeability to pesticides.

PubMed

Weir, Scott M; Talent, Larry G; Anderson, Todd A; Salice, Christopher J

2016-07-01

There is growing interest in improving ecological risk assessment exposure estimation, specifically by incorporating dermal exposure. At the same time, there is a growing interest in amphibians and reptiles as receptors in ecological risk assessment, despite generally receiving less research than more traditional receptors. Previous research has suggested that dermal exposure may be more important than previously considered for reptiles. We measured reptile skin permeability to four pesticides (thiamethoxam, malathion, tebuthiuron, trifluralin) using ventral skin samples. All four pesticides penetrated the skin but generally had low permeability. There was no apparent relationship between physicochemical properties and permeability coefficients. Malathion had a significantly greater permeability rate at all time points compared to the other pesticides. Tebuthiuron had a greater permeability than thiamethoxam. Reptiles and mammals appear to have similar skin permeability suggesting that dermal exposure estimates for mammals may be representative of reptiles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Linking field and laboratory studies to investigate nitrate removal using permeable reactive barrier technology during managed recharge

NASA Astrophysics Data System (ADS)

Gorski, G.; Beganskas, S.; Weir, W. B.; Redford, K.; Saltikov, C.; Fisher, A. T.

2017-12-01

We present data from a series of field and laboratory studies investigating mechanisms for the enhanced removal of nitrate during infiltration as a part of managed recharge. These studies combine physical, geochemical, and microbiological data collected during controlled infiltration experiments at both a plot and a laboratory scale using permeable reactive barrier (PRB) technology. The presence of a PRB, made of wood chips or biochar, enhances nitrate removal by stimulating the growth and productivity of native soil microbes to process nitrate via denitrification. Earlier work has shown that unamended soil can remove up to 50% of nitrate during infiltration at rates <1 m/day, but at higher infiltration rates nitrate removal dramatically decreases as too much oxygen is introduced, and the necessary conditions for denitrification do not develop. Our plot scale studies show that up to 40% of incoming nitrate can consistently be removed even at infiltration rates ≥1 m/day if there is a PRB made of wood chips. Slightly less nitrate is removed in the presence of a biochar PRB and there is little to no change in nitrate concentration at similarly high infiltration rates through unamended soil. Preliminary microbiological data show significant population changes below the PRB where most of the cycling occurs. Coupled with isotopic analyses, these results suggest that a PRB expands the range of infiltration rates at which significant nitrate can be removed by microbial activity. Further, nitrate removal occurs at different depths below the biochar and redwood chips, suggesting different mechanisms of nitrate removal in the presence of different PRB materials. In laboratory studies we flowed artificial groundwater through intact sediment cores collected at the same field site where we also ran infiltration tests. These experiments show that the fluid flow rate and the presence of a PRB exhibit primary control on nitrate removal during infiltration, and that the

Laboratory investigation of supported permeable organic covers for the management of odour emissions from anaerobic piggery waste ponds.

PubMed

Hudson, N; Casey, K; Melvin, S; Nicholas, P

2001-01-01

Australian research has linked much of the odour arising from intensive livestock operations to pond treatment systems. A reduction in emissions from treatment ponds would therefore generally reduce odour emissions from intensive livestock operations. Published data indicates that the application of straw and other biological materials to effluent pond surfaces as a continuous cover reduces odour emissions. The effectiveness of these covers has not, however, been researched under controlled conditions. Using locally available materials, the efficacy of supported covers has been investigated using a series of laboratory anaerobic digesters treating typical piggery effluent. Research to date has focused on: identifying effective cover and cover support materials; quantifying odour reduction; identifying the impact use these covers may have on greenhouse gas emissions; devising practical and effective methods for constructing these covers. Results have confirmed that a variety of cover materials are effective in reducing pond odour emissions. Supporting the pond cover appears to extend the cover life expectancy. While greenhouse gas emissions appear to vary according to cover type, the overall significance of these emissions is not yet clear. The impact of permeable pond covers on overall pond performance requires additional research.

High Stress Consolidation, Ultrasonic, and Permeability Measurements: Constraints on Physical Properties and In Situ Stress along the Costa Rica Subduction Plate Interface

NASA Astrophysics Data System (ADS)

Winner, A.; Saffer, D. M.; Valdez, R. D.

2014-12-01

Sediment permeability and consolidation behavior are key parameters in governing the drainage state and thus potential for excess pore fluid pressure in subduction zones. Elevated pore pressure, in turn, is one important control on the strength and sliding behavior of faults. Along many subduction margins, evidence of elevated, near-lithostatic, in situ pore pressure comes from high seismic reflectivity, low P-wave velocity (Vp), and high Vp/Vs ratios. This inference is broadly supported by numerical modeling studies that indicate elevated pore pressures are likely given high rates of burial and tectonic loading, combined with the low permeability of marine mudstones. Here, we report on a series of high-stress consolidation experiments on sediment core samples from the incoming Cocos plate obtained as part of Integrated Ocean Drilling Program (IODP) Expedition 344. Our experiments were designed to measure the consolidation behavior, permeability, and P-wave velocity of the incoming sediments over a range of confining stresses from .5 to 90 MPa. We explore a range of paths,including isostatic loading (σ1=σ2=σ3), K0 consolidation, in which the ratio of σ3/σ1 is maintained at ~0.6, and the trixial loading paths designed to maintain a near critical-state failure condition. In our tests, load is increased in a series of steps. After equilibration at each step, we conduct constant head permeability tests, and measure P-wave velocities in a "time of flight" mode. Initial results from isostatic loading tests on hemipelagic mudstone samples from 34 mbsf document consolidation and permeability-porosity trends, in which porosity decreases from 69% to 54% as stress in increased from .5 MPa to 15 MPa, and permeability decreases from 8.1 X 10-18 m2 at 1 MPa to 1.1 X 10-19 m2 at 15 MPa. P-wave velocity increases by 486-568 km/s over this effective stress range. Ultimately, data from our experiments will provide a robust basis for quantifying fluid content and pressure from

Gradual changes in permeability of inner mitochondrial membrane precede the mitochondrial permeability transition.

PubMed

Balakirev, M Y; Zimmer, G

1998-08-01

Some compounds are known to induce solute-nonselective permeability of the inner mitochondrial membrane (IMM) in Ca2+-loaded mitochondria. Existing data suggest that this process, following the opening of a mitochondrial permeability transition pore, is preceded by different solute-selective permeable states of IMM. At pH 7, for instance, the K0.5 for Ca2+-induced pore opening is 16 microM, a value 80-fold above a therapeutically relevant shift of intracellular Ca2+ during ischemia in vivo. The present work shows that in the absence of Ca2+, phenylarsine oxide and tetraalkyl thiuram disulfides (TDs) are able to induce a complex sequence of IMM permeability changes. At first, these agents activated an electrogenic K+ influx into the mitochondria. This K+-specific pathway had K0.5 = 35 mM for K+ and was inhibited by bromsulfalein with Ki = 2.5 microM. The inhibitors of mitochondrial KATP channel, ATP and glibenclamide, did not inhibit K+ transport via this pathway. Moreover, 50 microM glibenclamide induced by itself K+ influx into the mitochondria. After the increase in K+ permeability of IMM, mitochondria become increasingly permeable to protons. Mechanisms of H+ leak and nonselective permeability increase could also be different depending on the type of mitochondrial permeability transition (MPT) inducer. Thus, permeabilization of mitochondria induced by phenylarsine oxide was fully prevented by ADP and/or cyclosporin A, whereas TD-induced membrane alterations were insensitive toward these inhibitors. It is suggested that MPT in vivo leading to irreversible apoptosis is irrelevant in reversible ischemia/reperfusion injury. Copyright 1998 Academic Press.

Upscaling pore pressure-dependent gas permeability in shales

NASA Astrophysics Data System (ADS)

Ghanbarian, Behzad; Javadpour, Farzam

2017-04-01

Upscaling pore pressure dependence of shale gas permeability is of great importance and interest in the investigation of gas production in unconventional reservoirs. In this study, we apply the Effective Medium Approximation, an upscaling technique from statistical physics, and modify the Doyen model for unconventional rocks. We develop an upscaling model to estimate the pore pressure-dependent gas permeability from pore throat size distribution, pore connectivity, tortuosity, porosity, and gas characteristics. We compare our adapted model with six data sets: three experiments, one pore-network model, and two lattice-Boltzmann simulations. Results showed that the proposed model estimated the gas permeability within a factor of 3 of the measurements/simulations in all data sets except the Eagle Ford experiment for which we discuss plausible sources of discrepancies.

Permeability of rock samples from Cajon Pass, California

USGS Publications Warehouse

Morrow, C.; Byerlee, J.

1988-01-01

Room temperature, steady-state flow measurements of permeability were conducted on 15 unfractured core samples collected at depths between 270 and 2100 m in the Cajon Pass drillhole. Confining and pore pressures were set to the lithostat and hydrostat for each depth. The first 500 m encountered in the drill hole is composed of sandstones with typically high permeabilities of around 10-17m2. The crystalline rocks between 500 and 2100 m show a systematic decrease in permeability with depth from 10-19 to less than 10-21m2. These values are particularly low relative to the applied effective stresses of only 10-30 MPa, and may be a result of the extensive crack healing that was observed in most samples. -Authors

The impacts of effective stress and CO 2 sorption on the matrix permeability of shale reservoir rocks [The impacts of CO 2 sorption and effective stress on the matrix permeability of shale reservoir rocks

DOE PAGES

Wu, Wei; Zoback, Mark D.; Kohli, Arjun H.

2017-05-02

We assess the impacts of effective stress and CO 2 sorption on the bedding-parallel matrix permeability of the Utica shale through pressure pulse-decay experiments. We first measure permeability using argon at relatively high (14.6 MPa) and low (2.8 MPa) effective stresses to assess both pressure dependence and recoverability. We subsequently measure permeability using supercritical CO 2 and again using argon to assess changes due to CO 2 sorption. We find that injection of both argon and supercritical CO 2 reduces matrix permeability in distinct fashion. Samples with permeability higher than 10 –20 m 2 experience a large permeability reduction aftermore » treatment with argon, but a minor change after treatment with supercritical CO 2. However, samples with permeability lower than this threshold undergo a slight change after treatment with argon, but a dramatic reduction after treatment with supercritical CO 2. These results indicate that effective stress plays an important role in the evolution of relatively permeable facies, while CO 2 sorption dominates the change of ultra-low permeability facies. The permeability reduction due to CO 2 sorption varies inversely with initial permeability, which suggests that increased surface area from hydraulic stimulation with CO 2 may be counteracted by sorption effects in ultra-low permeability facies. As a result, we develop a conceptual model to explain how CO 2 sorption induces porosity reduction and volumetric expansion to constrict fluid flow pathways in shale reservoir rocks.« less

The impacts of effective stress and CO 2 sorption on the matrix permeability of shale reservoir rocks [The impacts of CO 2 sorption and effective stress on the matrix permeability of shale reservoir rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Wei; Zoback, Mark D.; Kohli, Arjun H.

We assess the impacts of effective stress and CO 2 sorption on the bedding-parallel matrix permeability of the Utica shale through pressure pulse-decay experiments. We first measure permeability using argon at relatively high (14.6 MPa) and low (2.8 MPa) effective stresses to assess both pressure dependence and recoverability. We subsequently measure permeability using supercritical CO 2 and again using argon to assess changes due to CO 2 sorption. We find that injection of both argon and supercritical CO 2 reduces matrix permeability in distinct fashion. Samples with permeability higher than 10 –20 m 2 experience a large permeability reduction aftermore » treatment with argon, but a minor change after treatment with supercritical CO 2. However, samples with permeability lower than this threshold undergo a slight change after treatment with argon, but a dramatic reduction after treatment with supercritical CO 2. These results indicate that effective stress plays an important role in the evolution of relatively permeable facies, while CO 2 sorption dominates the change of ultra-low permeability facies. The permeability reduction due to CO 2 sorption varies inversely with initial permeability, which suggests that increased surface area from hydraulic stimulation with CO 2 may be counteracted by sorption effects in ultra-low permeability facies. As a result, we develop a conceptual model to explain how CO 2 sorption induces porosity reduction and volumetric expansion to constrict fluid flow pathways in shale reservoir rocks.« less

Intestinal permeability study of minoxidil: assessment of minoxidil as a high permeability reference drug for biopharmaceutics classification.

PubMed

Ozawa, Makoto; Tsume, Yasuhiro; Zur, Moran; Dahan, Arik; Amidon, Gordon L

2015-01-05

The purpose of this study was to evaluate minoxidil as a high permeability reference drug for Biopharmaceutics Classification System (BCS). The permeability of minoxidil was determined in in situ intestinal perfusion studies in rodents and permeability studies across Caco-2 cell monolayers. The permeability of minoxidil was compared with that of metoprolol, an FDA reference drug for BCS classification. In rat perfusion studies, the permeability of minoxidil was somewhat higher than that of metoprolol in the jejunum, while minoxidil showed lower permeability than metoprolol in the ileum. The permeability of minoxidil was independent of intestinal segment, while the permeability of metoprolol was region-dependent. Similarly, in mouse perfusion study, the jejunal permeability of minoxidil was 2.5-fold higher than that of metoprolol. Minoxidil and metoprolol showed similar permeability in Caco-2 study at apical pH of 6.5 and basolateral pH of 7.4. The permeability of minoxidil was independent of pH, while metoprolol showed pH-dependent transport in Caco-2 study. Minoxidil exhibited similar permeability in the absorptive direction (AP-BL) in comparison with secretory direction (BL-AP), while metoprolol had higher efflux ratio (ER > 2) at apical pH of 6.5 and basolateral pH of 7.4. No concentration-dependent transport was observed for either minoxidil or metoprolol transport in Caco-2 study. Verapamil did not alter the transport of either compounds across Caco-2 cell monolayers. The permeability of minoxidil was independent of both pH and intestinal segment in intestinal perfusion studies and Caco-2 studies. Caco-2 studies also showed no involvement of carrier mediated transport in the absorption process of minoxidil. These results suggest that minoxidil may be an acceptable reference drug for BCS high permeability classification. However, minoxidil exhibited higher jejunal permeability than metoprolol and thus to use minoxidil as a reference drug would raise the

The generation and evolution of anisotropic gas-permeability during viscous deformation in conduit-filling ignimbrites

NASA Astrophysics Data System (ADS)

Kolzenburg, Stephan; Russell, Kelly

2015-04-01

Gas-permeability plays a governing role in the pre-explosive pressurization of volcanic edifices. Pressurization may only occur once the total volume flux of gases emitted by an underlying magmatic or hydrothermal source exceeds the flow capacity of the permeable pathways present in the edifice. We have measured the physical properties (strain, porosity, permeability and ultrasonic wave velocities) of breadcrust bombs recovered from the deposits of the 2350 B.P. eruption of Mt Meager, BC, Canada. These rocks represent a conduit-infilling pyroclastic breccia that underwent various degrees of welding and deformation and present a remarkable opportunity to constrain the nature and timescale of mechanical processes operating within explosive volcanic conduits during repose periods between eruptive cycles. Here we present data from permeability measurements along the directions of maximum and minimum shortening which help quantifying the effect of vesicle microstructure on permeability. Permeability is measured by applying a range of confining pressures (between 3.4 and 17.2 MPa) to each sample and imposing a constant head (of 0.2 to 3.5 MPa) across the sample. The permeability is then determined using a modified version of Darcy's law applicable to compressible fluids. These rocks display a profound directionality in the measured physical properties resulting from the deformation-induced fabric. For all samples the permeability across the elongation fabric is highly correlated to the sample porosity whereas along the elongation fabric there is little effect of porosity on permeability. At porosity values of about 20% the permeability seems to reach a minimum at 10-16 m2 and does not change significantly with further reduction of porosity. Further, the effect of confining pressure on the permeability of these samples appears to be more pronounced across the elongation fabric than along the elongation fabric. The deformation fabric has a significant effect on the gas-permeability

Fracture and healing in magmas: a dual role on permeability evolution

NASA Astrophysics Data System (ADS)

Lamur, Anthony; Lavallée, Yan; Wall, Richard; Ashworth, James; Kendrick, Jackie; Wadsworth, Fabian

2016-04-01

The development of a permeable network in silicic volcanic conduits controls outgassing and plays a major role on the subsequent eruptive behaviour. Efficient outgassing, at higher permeabilities, is achieved through the coalescence of pores and fractures. Whilst the relationship between permeability and increasing connected porosity is now relatively well constrained, the effects of fractures have, on the other hand, rarely been investigated. Here, we present the results of an experimental study focusing on the impacts of tensile fracturing and healing on permeability. Permeability measurements have been performed on over 60 disk-shaped samples (26 mm diameter, 13 mm thickness) with connected porosities ranging from 2 to 45%. Our results for unfractured samples display the same porosity-permeability trend as previous studies and permeabilities span from 10-15 at low porosities to over 5x10-12 m2 at higher porosities. These samples were then broken via Brazilian tests and the resultant permeability of the rocks were then measured across the fracture zone. Whilst high porosity samples reached permeabilities of about 5x10-10 m2 (2 orders of magnitude higher than intact samples), low porosity samples, on the other hand, reached permeabilities around 5x10-12 m2 (more than 3 orders of magnitude above intact samples). Our results show that fracturing favours the development of a permeable network that adheres to a different permeability-porosity relationship than previously presented, and that this effect is emphasized in magmas with low connected porosities. The effect of fracture healing by diffusion on permeability has been investigated through a series of experiments on borosilicate standard glass (NIST 717a). These experiments were conducted at 560oC (viscosity of 1010.33 Pa.s) on pairs of columns pressed and held in contact at constant load for times varying between 0.5s and 15000 s before being pulled apart at a strain rate of 10-3s-1. Using Maxwell's theory of

Measuring preschool learning engagement in the laboratory.

PubMed

Halliday, Simone E; Calkins, Susan D; Leerkes, Esther M

2018-03-01

Learning engagement is a critical factor for academic achievement and successful school transitioning. However, current methods of assessing learning engagement in young children are limited to teacher report or classroom observation, which may limit the types of research questions one could assess about this construct. The current study investigated the validity of a novel assessment designed to measure behavioral learning engagement among young children in a standardized laboratory setting and examined how learning engagement in the laboratory relates to future classroom adjustment. Preschool-aged children (N = 278) participated in a learning-based Tangrams task and Story sequencing task and were observed based on seven behavioral indicators of engagement. Confirmatory factor analysis supported the construct validity for a behavioral engagement factor composed of six of the original behavioral indicators: attention to instructions, on-task behavior, enthusiasm/energy, persistence, monitoring progress/strategy use, and negative affect. Concurrent validity for this behavioral engagement factor was established through its associations with parent-reported mastery motivation and pre-academic skills in math and literacy measured in the laboratory, and predictive validity was demonstrated through its associations with teacher-reported classroom learning behaviors and performance in math and reading in kindergarten. These associations were found when behavioral engagement was observed during both the nonverbal task and the verbal story sequencing tasks and persisted even after controlling for child minority status, gender, and maternal education. Learning engagement in preschool appears to be successfully measurable in a laboratory setting. This finding has implications for future research on the mechanisms that support successful academic development. Copyright © 2017 Elsevier Inc. All rights reserved.

Sensitivity, specificity, and reproducibility of four measures of laboratory turnaround time.

PubMed

Valenstein, P N; Emancipator, K

1989-04-01

The authors studied the performance of four measures of laboratory turnaround time: the mean, median, 90th percentile, and proportion of tests reported within a predetermined cut-off interval (proportion of acceptable tests [PAT]). Measures were examined with the use of turnaround time data from 11,070 stat partial thromboplastin times, 16,761 urine cultures, and 28,055 stat electrolyte panels performed by a single laboratory. For laboratories with long turnaround times, the most important quality of a turnaround time measure is high reproducibility, so that improvement in reporting speed can be distinguished from random variation resulting from sampling. The mean was found to be the most reproducible of the four measures, followed by the median. The mean achieved acceptable precision with sample sizes of 100-500 tests. For laboratories with normally rapid turnaround times, the most important quality of a measure is high sensitivity and specificity for detecting whether turnaround time has dropped below standards. The PAT was found to be the best measure of turnaround time in this setting but required sample sizes of at least 500 tests to achieve acceptable accuracy. Laboratory turnaround time may be measured for different reasons. The method of measurement should be chosen with an eye toward its intended application.

Iron abundance and magnetic permeability of the moon

NASA Technical Reports Server (NTRS)

Parkin, C. W.; Daily, W. D.; Dyal, P.

1974-01-01

A larger set of simultaneous data from the Apollo 12 lunar surface magnetometer and the Explorer 35 Ames magnetometer are used to construct a whole-moon hysteresis curve, from which a new value of global lunar permeability is determined to be mu = 1.012 + or - 0.006. The corresponding global induced dipole moment is 2.1 x 10 to the 18th power gauss-cu cm for typical inducing fields of .0001 gauss in the lunar environment. From the permeability measurement, lunar free iron abundance is determined to be 2.5 + or - 2.0 wt. %. Total iron abundance (sum of iron in the ferromagnetic and paramagnetic states) is calculated for two assumed compositional models of the lunar interior: a free iron/orthopyroxene lunar composition and a free iron/olivine composition. The overall lunar total iron abundance is determined to be 9.0 + or - 4.7 wt. %. Other lunar models with a small iron core and with a shallow iron-rich layer are discussed in light of the measured global permeability.

Leaky gut and mycotoxins: Aflatoxin B1 does not increase gut permeability in broiler chickens

USDA-ARS?s Scientific Manuscript database

Previous studies conducted in our laboratory have demonstrated that intestinal barrier function can be adversely affected by diet ingredients or feed restriction, resulting in increased intestinal inflammation-associated permeability. Two experiments were conducted in broilers to evaluate the effect...

Greater scaffold permeability promotes growth of osteoblastic cells in a perfused bioreactor.

PubMed

Fan, Jie; Jia, Xiaoling; Huang, Yan; Fu, Bingmei M; Fan, Yubo

2015-12-01

Pore size and porosity have been widely acknowledged as important structural factors in tissue-engineered scaffolds. In fact, scaffolds with similar pore size and porosity can provide important and varied permeability due to different pore shape, interconnectivity and tortuosity. However, the effects of scaffold permeability on seeded cells remains largely unknown during tissue regeneration in vitro. In this study, we measured the Darcy permeability (K) of tri-calcium phosphate scaffolds by distributed them into three groups: Low, Medium and High. As a result, the effects of scaffold permeability on cell proliferation, cellular activity and growth in the inner pores were investigated in perfused and static cultures in vitro. Results demonstrated that higher permeable scaffolds exhibited superior performance during bone regeneration in vitro and the advantages of higher scaffold permeability were amplified in perfused culture. Based on these findings, scaffold permeability should be considered in future scaffold fabrications. Copyright © 2013 John Wiley & Sons, Ltd.

Dabigatran abrogates brain endothelial cell permeability in response to thrombin

PubMed Central

Hawkins, Brian Thomas; Gu, Yu-Huan; Izawa, Yoshikane; del Zoppo, Gregory John

2015-01-01

Atrial fibrillation (AF) increases the risk and severity of thromboembolic stroke. Generally, antithrombotic agents increase the hemorrhagic risk of thromboembolic stroke. However, significant reductions in thromboembolism and intracerebral hemorrhage have been shown with the antithrombin dabigatran compared with warfarin. As thrombin has been implicated in microvessel injury during cerebral ischemia, we hypothesized that dabigatran decreases the risk of intracerebral hemorrhage by direct inhibition of the thrombin-mediated increase in cerebral endothelial cell permeability. Primary murine brain endothelial cells (mBECs) were exposed to murine thrombin before measuring permeability to 4-kDa fluorescein isothiocyanate-dextran. Thrombin increased mBEC permeability in a concentration-dependent manner, without significant endothelial cell death. Pretreatment of mBECs with dabigatran completely abrogated the effect of thrombin on permeability. Neither the expressions of the endothelial cell β1-integrins nor the tight junction protein claudin-5 were affected by thrombin exposure. Oxygen-glucose deprivation (OGD) also increased permeability; this effect was abrogated by treatment with dabigatran, as was the additive effect of thrombin and OGD on permeability. Taken together, these results indicate that dabigatran could contribute to a lower risk of intracerebral hemorrhage during embolism-associated ischemia from AF by protection of the microvessel permeability barrier from local thrombin challenge. PMID:25669912

MEAUSREMENT OF THE SURFACE PERMEABILITY OF BASEMENT CONCRETES

EPA Science Inventory

The report discusses the development, testing, and use of a portable surface permeameter suitable for field use in measuring the surface permeability of concrete in new houses. he permeameter measures the airflow induced by a pressure difference across a temporary test seal appli...

Optimizing Fluorescein Isothiocyanate Dextran Measurement As a Biomarker in a 24-h Feed Restriction Model to Induce Gut Permeability in Broiler Chickens

PubMed Central

Baxter, Mikayla F. A.; Merino-Guzman, Ruben; Latorre, Juan D.; Mahaffey, Brittany D.; Yang, Yichao; Teague, Kyle D.; Graham, Lucas E.; Wolfenden, Amanda D.; Hernandez-Velasco, Xochitl; Bielke, Lisa R.; Hargis, Billy M.; Tellez, Guillermo

2017-01-01

Fluorescein isothiocyanate dextran (FITC-d) is a 3–5 kDa marker used to measure tight junction permeability. We have previously shown that intestinal barrier function can be adversely affected by stress, poorly digested diets, or feed restriction (FR), resulting in increased intestinal inflammation-associated permeability. However, further optimization adjustments of the current FITC-d methodology are possible to enhance precision and efficacy of results in future. The objective of the present study was to optimize our current model to obtain a larger difference between control and treated groups, by optimizing the FITC-d measurement as a biomarker in a 24-h FR model to induce gut permeability in broiler chickens. One in vitro and four in vivo independent experiments were conducted. The results of the present study suggest that by increasing the dose of FITC-d (8.32 versus 4.16 mg/kg); shortening the collection time of blood samples (1 versus 2.5 h); using a pool of non-FITC-d serum as a blank, compared to previously used PBS; adding a standard curve to set a limit of detection and modifying the software’s optimal sensitivity value, it was possible to obtain more consistent and reliable results. PMID:28470003

Membrane hydraulic permeability changes during cooling of mammalian cells.

PubMed

Akhoondi, Maryam; Oldenhof, Harriëtte; Stoll, Christoph; Sieme, Harald; Wolkers, Willem F

2011-03-01

In order to predict optimal cooling rates for cryopreservation of cells, the cell-specific membrane hydraulic permeability and corresponding activation energy for water transport need to be experimentally determined. These parameters should preferably be determined at subzero temperatures in the presence of ice. There is, however, a lack of methods to study membrane properties of cells in the presence of ice. We have used Fourier transform infrared spectroscopy to study freezing-induced membrane dehydration of mouse embryonic fibroblast (3T3) cells and derived the subzero membrane hydraulic permeability and the activation energy for water transport from these data. Coulter counter measurements were used to determine the suprazero membrane hydraulic permeability parameters from cellular volume changes of cells exposed to osmotic stress. The activation energy for water transport in the ice phase is about three fold greater compared to that at suprazero temperatures. The membrane hydraulic permeability at 0 °C that was extrapolated from suprazero measurements is about five fold greater compared to that extrapolated from subzero measurements. This difference is likely due to a freezing-induced dehydration of the bound water around the phospholipid head groups. Using Fourier transform infrared spectroscopy, two distinct water transport processes, that of free and membrane bound water, can be identified during freezing with distinct activation energies. Dimethylsulfoxide, a widely used cryoprotective agent, did not prevent freezing-induced membrane dehydration but decreased the activation energy for water transport. Copyright © 2010 Elsevier B.V. All rights reserved.

Porosity, petrophysics and permeability of the Whitby Mudstone (UK)

NASA Astrophysics Data System (ADS)

Houben, M.; Barnhoorn, A.; Hardebol, N.; Ifada, M.; Boersma, Q.; Douma, L.; Peach, C. J.; Bertotti, G.; Drury, M. R.

2016-12-01

Typically pore diameters in shales range from the µm down to the nm scale and the effective permeability of shale reservoirs is a function of the interconnectivity between the pore space and the natural fracture network present. The length and spacing of mechanical induced and natural fractures is one of the factors controlling gas produtivity from unconventional reservoirs. Permeability of the Whitby Mudstone measured on 1 inch cores was linked to microstructure and combined with natural fracture spacing present in outcrops along the Yorkshire coast (UK) to get insight into possible fluid pathways from reservoir to well. We used a combination of different techniques to characterize the porosity (gas adsorption, Scanning Electron Microscopy), mineralogy (X-Ray Fluorescence, X-Ray Diffraction, Scanning Electron Microscopy) and permeability (pressure step decay) of the Whitby Mudstone. In addition, we mapped the natural fracture network as present in outcrops along the Yorkshire coast (UK) at the 10-2-101m scale. Mineralogically we are dealing with a rock that is high in clay content and has an average organic matter content of about 10%. Results show a low porosity (max. 7%) as well as low permeability for the Whitby Mudstone. The permeability, measured parallel to bedding, depends on the confining pressure and is 86 nanodarcy at 10 MPa effective confining pressure and decreases to 16 nanodarcy at 40 MPa effective confining pressure. At the scale of observation the average distance to nearest natural fracture is in the order of 0.13 meter and 90 percent of all matrix elements are spaced within 0.4 meter to the nearest fracture. By assuming darcy flow, a permeability of 100 nanodarcy and 10% of overpressure we calculated that for the Whitby mudstone most of the gas resides in the matrix for less than 60 days until it reaches the fracture network.

Intestinal Membrane Permeability and Hypersensitivity In the Irritable Bowel Syndrome

PubMed Central

Zhou, QiQi; Zhang, Buyi; Verne, G. Nicholas

2009-01-01

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder in which the underlying pathophysiology is poorly understood; however, increased intestinal permeability in diarrhea-predominant IBS patients has been reported. Here we demonstrate diarrhea-predominant IBS patients (D-IBS) that display increased intestinal permeability. We have also found that increased intestinal membrane permeability is associated with visceral and thermal hypersensitivity in this subset of D-IBS patients. We evaluated 54 D-IBS patients and 22 controls for intestinal membrane permeability using the lactulose / mannitol method. All subjects ingested 5 g laclulose and 2 g mannitol in 100 ml of water after which their urine was collected. We also evaluated the mean mechanical visual analogue (MVAS) pain rating to nociceptive thermal and visceral stimulation in all subjects. All study participants also completed the FBDSI scale. Approximately 39% of diarrhea-predominant IBS patients have increased intestinal membrane permeability as measured by the lactulose / mannitol ratio. These IBS patients also demonstrated higher M-VAS pain intensity reading scale. Interestingly, the IBS patients with hypersensitivity and increased intestinal permeability had a higher FBDSI score (100.8±5.4) compared to IBS patients with normal membrane permeability and sensitivity (51.6±12.7) and controls (6.1 ± 5.6) (p<0.001). A subset of D-IBS patients have increased intestinal membrane permeability that is associated with an increased FBDSI score and increased hypersensitivity to visceral and thermal nociceptive pain stimuli. Thus, increased intestinal membrane permeability in D-IBS patients may lead to more severe IBS symptoms and hypersensitivity to somatic and visceral stimuli. PMID:19595511

Do the recommended standards for in vitro biopharmaceutic classification of drug permeability meet the "passive transport" criterion for biowaivers?

PubMed

Žakelj, Simon; Berginc, Katja; Roškar, Robert; Kraljič, Bor; Kristl, Albin

2013-01-01

BCS based biowaivers are recognized by major regulatory agencies. An application for a biowaiver can be supported by or even based on "in vitro" measurements of drug permeability. However, guidelines limit the application of biowaivers to drug substances that are transported only by passive mechanisms. Regarding published permeability data as well as measurements obtained in our institution, one can rarely observe drug substances that conform to this very strict criterion. Therefore, we measured the apparent permeability coefficients of 13 drugs recommended by FDA's Guidance to be used as standards for "in vitro" permeability classification. The asymmetry of permeability data determined for both directions (mucosal-to-serosal and serosalto- mucosal) through the rat small intestine revealed significant active transport for four out of the nine high-permeability standards and for all four low-permeability standard drugs. As could be expected, this asymmetry was abolished at 4°C on rat intestine. The permeability of all nine high-permeability, but none of the low permeability standards, was also much lower when measured with intestinal tissue, Caco-2 cell monolayers or artificial membranes at 4°C compared to standard conditions (37°C). Additionally, concurrent testing of several standard drugs revealed that membrane transport can be affected by the use of internal permeability standards. The implications of the results are discussed regarding the regulatory aspects of biopharmaceutical classification, good practice in drug permeability evaluation and regarding the general relevance of transport proteins with broad specificity in drug absorption.

Bayesian inference for heterogeneous caprock permeability based on above zone pressure monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Namhata, Argha; Small, Mitchell J.; Dilmore, Rober

The presence of faults/ fractures or highly permeable zones in the primary sealing caprock of a CO2 storage reservoir can result in leakage of CO2. Monitoring of leakage requires the capability to detect and resolve the onset, location, and volume of leakage in a systematic and timely manner. Pressure-based monitoring possesses such capabilities. This study demonstrates a basis for monitoring network design based on the characterization of CO2 leakage scenarios through an assessment of the integrity and permeability of the caprock inferred from above zone pressure measurements. Four representative heterogeneous fractured seal types are characterized to demonstrate seal permeability rangingmore » from highly permeable to impermeable. Based on Bayesian classification theory, the probability of each fractured caprock scenario given above zone pressure measurements with measurement error is inferred. The sensitivity to injection rate and caprock thickness is also evaluated and the probability of proper classification is calculated. The time required to distinguish between above zone pressure outcomes and the associated leakage scenarios is also computed.« less

Defects level evaluation of LiTiZn ferrite ceramics using temperature dependence of initial permeability

NASA Astrophysics Data System (ADS)

Malyshev, A. V.; Petrova, A. B.; Sokolovskiy, A. N.; Surzhikov, A. P.

2018-06-01

The method for evaluating the integral defects level and chemical homogeneity of ferrite ceramics based on temperature dependence analysis of initial permeability is suggested. A phenomenological expression for the description of such dependence was suggested and an interpretation of its main parameters was given. It was shown, that the main criterion of the integral defects level of ferrite ceramics is relation of two parameters correlating with elastic stress value in a material. An indicator of structural perfection can be a maximum value of initial permeability close to Curie point as well. The temperature dependences of initial permeability have analyzed for samples sintered in laboratory conditions and for the ferrite industrial product. The proposed method allows controlling integral defects level of the soft ferrite products and has high sensitivity compare to typical X-ray methods.

Continuous Record of Permeability inside the Wenchuan Earthquake Fault Zone

NASA Astrophysics Data System (ADS)

Xue, L.; Li, H.; Brodsky, E. E.; Wang, H.; Pei, J.

2012-12-01

Faults are complex hydrogeological structures which include a highly permeable damage zone with fracture-dominated permeability. Since fractures are generated by earthquakes, we would expect that in the aftermath of a large earthquake, the permeability would be transiently high in a fault zone. Over time, the permeability may recover due to a combination of chemical and mechanical processes. However, the in situ fault zone hydrological properties are difficult to measure and have never been directly constrained on a fault zone immediately after a large earthquake. In this work, we use water level response to solid Earth tides to constrain the hydraulic properties inside the Wenchuan Earthquake Fault Zone. The transmissivity and storage determine the phase and amplitude response of the water level to the tidal loading. By measuring phase and amplitude response, we can constrain the average hydraulic properties of the damage zone at 800-1200 m below the surface (˜200-600 m from the principal slip zone). We use Markov chain Monte Carlo methods to evaluate the phase and amplitude responses and the corresponding errors for the largest semidiurnal Earth tide M2 in the time domain. The average phase lag is ˜30°, and the average amplitude response is 6×10-7 strain/m. Assuming an isotropic, homogenous and laterally extensive aquifer, the average storage coefficient S is 2×10-4 and the average transmissivity T is 6×10-7 m2 using the measured phase and the amplitude response. Calculation for the hydraulic diffusivity D with D=T/S, yields the reported value of D is 3×10-3 m2/s, which is two orders of magnitude larger than pump test values on the Chelungpu Fault which is the site of the Mw 7.6 Chi-Chi earthquake. If the value is representative of the fault zone, then this means the hydrology processes should have an effect on the earthquake rupture process. This measurement is done through continuous monitoring and we could track the evolution for hydraulic properties

Clay and Shale Permeability at Lab to Regional Scale

NASA Astrophysics Data System (ADS)

Neuzil, C.

2017-12-01

Because clays, shales, and other clay-rich media tend to be only poorly permeable, and are laterally extensive and voluminous, they play key roles in problems as diverse as groundwater supply, waste confinement, exploitation of conventional and unconventional oil and gas, and deformation and failure in the crust. Clay and shale permeability is a crucial but often highly uncertain analysis parameter; direct measurements are challenging, error-prone, and - perhaps most importantly - provide information only at quite small scales. Fortunately, there has been a dramatic increase in clay and shale permeability data from sources that include scientific ocean drilling, nuclear waste repository research, groundwater resource studies, liquid waste and CO2 sequestration, and oil and gas research. The effect of lithology as well as porosity on matrix permeability can now be examined and permeability - scale relations are becoming discernable. A significant number of large-scale permeability estimates have been obtained by inverse methods that essentially treat large-scale flow systems as natural experiments. They suggest surprisingly little scale-dependence in clay and shale permeabilities in subsiding basins and accretionary complexes. Stable continental settings present a different picture; as depths increase beyond 1 km, scale dependence mostly disappears even over the largest areas. At depths less than 1 km, secondary permeability is not always present over areas of 1 - 10 km2, but always evident for areas in excess of about 103 km2. Transmissive fractures have been observed in very low porosity (< 0.03) shales in these settings, but the cause of scale dependence in other cases is unclear; it may reflect time-dependent, or "dynamic" conditions, including irreversible and ongoing changes imposed on subsurface flow systems by human activities.

Lunar electrical conductivity, permeability,and temperature from Apollo magnetometer experiments

NASA Technical Reports Server (NTRS)

Dyal, P.; Parkin, C. W.; Daily, W. D.

1974-01-01

Magnetometers were deployed at four Apollo sites on the moon to measure remanent and induced lunar magnetic fields. Measurements from this network of instruments were used to calculate the electrical conductivity, temperature, magnetic permeability, and iron abundance of the lunar interior. Global lunar fields due to eddy currents, induced in the lunar interior by magnetic transients, were analyzed to calculate and electrical conductivity profile for the moon, and those profiles were used to calculate the lunar temperature for an assumed lunar material of olivine. Simultaneous measurements by magnetometers on the lunar surface and in orbit around the moon were use to construct a whole-moon hysteresis curve, from which the global lunar magnetic permeability is determined. Total iron abundance (sum of iron in the ferromagnetic and paramagnetic states) was calculated for two assumed compositional models of the lunar interior. Other lunar models with an iron core and with a shallow iron-rich layer also discussed in light of the measured global lunar permeability. Simultaneous magnetic field and solar plasma pressure measurements show that the remanent fields at the Apollo 12 and 16 sites interact with, and are compressed by, the solar wind. Velocities and thicknesses of the earth's magnetopause and bow shock were also estimated from simultaneous magnetometer measurements.

The effect of offset on fracture permeability of rocks from the Southern Andes Volcanic Zone, Chile

NASA Astrophysics Data System (ADS)

Pérez-Flores, P.; Wang, G.; Mitchell, T. M.; Meredith, P. G.; Nara, Y.; Sarkar, V.; Cembrano, J.

2017-11-01

The Southern Andes Volcanic Zone (SVZ) represents one of the largest undeveloped geothermal provinces in the world. Development of the geothermal potential requires a detailed understanding of fluid transport properties of its main lithologies. The permeability of SVZ rocks is altered by the presence of fracture damage zones produced by the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). We have therefore measured the permeability of four representative lithologies from the volcanic basement in this area: crystalline tuff, andesitic dike, altered andesite and granodiorite. For comparative purposes, we have also measured the permeability of samples of Seljadalur basalt, an Icelandic rock with widely studied and reported hydraulic properties. Specifically, we present the results of a systematic study of the effect of fractures and fracture offsets on permeability as a function of increasing effective pressure. Baseline measurements on intact samples of SVZ rocks show that the granodiorite has a permeability (10-18 m2), two orders of magnitude higher than that of the volcanic rocks (10-20 m2). The presence of throughgoing mated macro-fractures increases permeability by between four and six orders of magnitude, with the highest permeability recorded for the crystalline tuff. Increasing fracture offset to produce unmated fractures results in large increases in permeability up to some characteristic value of offset, beyond which permeability changes only marginally. The increase in permeability with offset appears to depend on fracture roughness and aperture, and these are different for each lithology. Overall, fractured SVZ rocks with finite offsets record permeability values consistent with those commonly found in geothermal reservoirs (>10-16 m2), which potentially allow convective/advective flow to develop. Hence, our results demonstrate that the fracture damage zones developed within the SVZ produce permeable regions, especially within the

Permeability structure and its influence on microbial activity at off-Shimokita basin, Japan

NASA Astrophysics Data System (ADS)

Tanikawa, W.; Yamada, Y.; Sanada, Y.; Kubo, Y.; Inagaki, F.

2016-12-01

The microbial populations and the limit of microbial life are probably limited by chemical, physical, and geological conditions, such as temperature, pore water chemistry, pH, and water activity; however, the key parameters affecting growth in deep subseafloor sediments remain unclarified (Hinrichs and Inagaki 2012). IODP expedition 337 was conducted near a continental margin basin off Shimokita Peninsula, Japan to investigate the microbial activity under deep marine coalbed sediments down to 2500 mbsf. Inagaki et al. (2015) discovered that microbial abundance decreased markedly with depth (the lowest cell density of <1 cell/cm3 was recorded below 2000 mbsf), and that the coal bed layers had relatively higher cell densities. In this study, permeability was measured on core samples from IODP Expedition 337 and Expedition CK06-06 in the D/V Chikyu shakedown cruise. Permeability was measured at in-situ effective pressure condition. Permeability was calculated by the steady state flow method by keeping differential pore pressure from 0.1 to 0.8 MPa.Our results show that the permeability for core samples decreases with depth from 10-16 m2 on the seafloor to 10-20 m2 at the bottom of hole. However, permeability is highly scattered within the coal bed unit (1900 to 2000 mbsf). Permeabilities for sandstone and coal is higher than those for siltstone and shale, therefore the scatter of the permeabilities at the same unit is due to the high variation of lithology. The highest permeability was observed in coal samples and this is probably due to formation of micro cracks (cleats). Permeability estimated from the NMR logging using the empirical parameters is around two orders of magnitude higher than permeability of core samples, even though the relative permeability variation at vertical direction is quite similar between core and logging data.The higher cell density is observed in the relatively permeable formation. On the other hand, the correlation between cell density

There and back again: The life and death of magma permeability in volcanic conduits

NASA Astrophysics Data System (ADS)

Wadsworth, F. B.; Vasseur, J.; Llewellin, E. W.; Lavallée, Y.; Kendrick, J. E.; Dobson, K. J.; Heap, M. J.; Kushnir, A. R.; Dingwell, D. B.

2017-12-01

Permeability of magma to gas is one of the key controls on the propoensity for explosive volcanism on the terrestrial planets. The magma filling upper-crustal volcanic conduits must become permeable in order for gas overpressure in pore spaces to dissipate. Once permeable, magma may densify and the pore network may re-seal itself. Permeability may be developed in one or more of 3 end-member pore-space geometries: (1) bubble-dominated, (2) crack-dominated, or (3) particle dominated. We take each geometry in turn and explore how we can scale the evolution of permeability with porosity. To do this we use 3 different data types. First, we compile the large body of published measurements of natural, synthetic and analogue volcanic rocks covering a range of pore space complexity. Second, we compile and conduct in situ measurements of permeability evolution for densifying granular systems or crack-formation in deforming magmas. Third, we conduct stochastic simulations in which we systematically build random heterogeneous porous media from overlapping spheres and use lattice-Boltzmann simulations of fluid flow to find the permeability. These data permit us to isolate individual controls on the permeability in each geometry in turn. Permeability can be readily formed by bubble coalescence, fracturing or fragmentation, and by forced gas percolation. Similarly, permeability can be reduced by bubble shrinking and pinch off, fracture healing, and volcanic welding. We broadly consider the kinetics of these processes and provide useful tools for predicting the longevity of different permeable network types. We summarize these findings by considering the potential of silicic volcanoes to outgas prior to significant overpressure buildup, possibly controlling the liklihood of large explosive behaviour.

NOAA's Van-Based Mobile Atmospheric Emissions Measurement Laboratory

NASA Astrophysics Data System (ADS)

Dube, W. P.; Peischl, J.; Neuman, J. A.; Eilerman, S. J.; Holloway, M.; Roberts, O.; Aikin, K. C.; Ryerson, T. B.

2015-12-01

The Chemical Science Division (CSD) mobile atmospheric emissions measurement laboratory is the second and latest of two mobile measurement vans outfitted for atmospheric sampling by the NOAA Earth System Research Laboratory. In this presentation we will describe the modifications made to this vehicle to provide a versatile and relatively inexpensive instrument platform including: the 2 kW 120 volt instrument power system; battery back-up system; data acquisition system; real-time display; meteorological, directional, and position sensor package; and the typical atmospheric emissions instrument package. The van conversion uses commercially available, off-the-shelf components from the marine and RV industries, thus keeping the costs quite modest.

Experimental studies and model analysis of noble gas fractionation in low-permeability porous media

NASA Astrophysics Data System (ADS)

Ding, Xin; Mack Kennedy, B.; Molins, Sergi; Kneafsey, Timothy; Evans, William C.

2017-05-01

Gas flow through the vadose zone from sources at depth involves fractionation effects that can obscure the nature of transport and even the identity of the source. Transport processes are particularly complex in low permeability media but as shown in this study, can be elucidated by measuring the atmospheric noble gases. A series of laboratory column experiments was conducted to evaluate the movement of noble gas from the atmosphere into soil in the presence of a net efflux of CO2, a process that leads to fractionation of the noble gases from their atmospheric abundance ratios. The column packings were designed to simulate natural sedimentary deposition by interlayering low permeability ceramic plates and high permeability beach sand. Gas samples were collected at different depths at CO2 fluxes high enough to cause extreme fractionation of the noble gases (4He/36Ar > 20 times the air ratio). The experimental noble gas fractionation-depth profiles were in good agreement with those predicted by the dusty gas (DG) model, demonstrating the applicability of the DG model across a broad spectrum of environmental conditions. A governing equation based on the dusty gas model was developed to specifically describe noble gas fractionation at each depth that is controlled by the binary diffusion coefficient, Knudsen diffusion coefficient and the ratio of total advection flux to total flux. Finally, the governing equation was used to derive the noble gas fractionation pattern and illustrate how it is influenced by soil CO2 flux, sedimentary sequence, thickness of each sedimentary layer and each layer's physical parameters. Three potential applications of noble gas fractionation are provided: evaluating soil attributes in the path of gas flow from a source at depth to the atmosphere, testing leakage through low permeability barriers used to isolate buried waste, and tracking biological methanogenesis and methane oxidation associated with hydrocarbon degradation.

Portable device and method for determining permeability characteristics of earth formations

DOEpatents

Shuck, Lowell Z.

1977-01-01

The invention is directed to a device which is used for determining permeability characteristics of earth formations at the surface thereof. The determination of the maximum permeability direction and the magnitude of permeability are achieved by employing a device comprising a housing having a central fluid-injection port surrounded by a plurality of spaced-apart fluid flow and pressure monitoring ports radially extending from the central injection port. With the housing resting on the earth formation in a relatively fluid-tight manner as provided by an elastomeric pad disposed therebetween, fluid is injected through the central port into the earth formation and into registry with the fluid-monitoring ports disposed about the injection port. The fluid-monitoring ports are selectively opened and the flow of the fluid through the various fluid ports is measured so as to provide a measurement of flow rates and pressure distribution about the center hole which is indicative on the earth formation permeability direction and magnitude. For example, the azimuthal direction of the fluid-monitoring ports in the direction through which the greatest amount of injected fluid flows as determined by the lowest pressure distribution corresponds to the direction of maximum permeability in the earth formation.

Permeability and seismic velocity anisotropy across a ductile-brittle fault zone in crystalline rock

NASA Astrophysics Data System (ADS)

Wenning, Quinn C.; Madonna, Claudio; de Haller, Antoine; Burg, Jean-Pierre

2018-05-01

This study characterizes the elastic and fluid flow properties systematically across a ductile-brittle fault zone in crystalline rock at the Grimsel Test Site underground research laboratory. Anisotropic seismic velocities and permeability measured every 0.1 m in the 0.7 m across the transition zone from the host Grimsel granodiorite to the mylonitic core show that foliation-parallel P- and S-wave velocities systematically increase from the host rock towards the mylonitic core, while permeability is reduced nearest to the mylonitic core. The results suggest that although brittle deformation has persisted in the recent evolution, antecedent ductile fabric continues to control the matrix elastic and fluid flow properties outside the mylonitic core. The juxtaposition of the ductile strain zone next to the brittle zone, which is bounded inside the two mylonitic cores, causes a significant elastic, mechanical, and fluid flow heterogeneity, which has important implications for crustal deformation and fluid flow and for the exploitation and use of geothermal energy and geologic waste storage. The results illustrate how physical characteristics of faults in crystalline rocks change in fault zones during the ductile to brittle transitions.

New Improvements in Magnetic Measurements Laboratory of the ALBA Synchrotron Facility

NASA Astrophysics Data System (ADS)

Campmany, Josep; Marcos, Jordi; Massana, Valentí

ALBA synchrotron facility has a complete insertion devices (ID) laboratory to characterize and produce magnetic devices needed to satisfy the requirements of ALBA's user community. The laboratory is equipped with a Hall-probe bench working in on-the-fly measurement mode allowing the measurement of field maps of big magnetic structures with high accuracy, both in magnetic field magnitude and position. The whole control system of this bench is based on TANGO. The Hall probe calibration range extends between sub-Gauss to 2 Tesla with an accuracy of 100 ppm. Apart from the Hall probe bench, the ID laboratory has a flipping coil bench dedicated to measuring field integrals and a Helmholtz coil bench specially designed to characterize permanent magnet blocks. Also, a fixed stretched wire bench is used to measure field integrals of magnet sets. This device is specifically dedicated to ID construction. Finally, the laboratory is equipped with a rotating coil bench, specially designed for measuring multipolar devices used in accelerators, such as quadrupoles, sextupoles, etc. Recent improvements of the magnetic measurements laboratory of ALBA synchrotron include the design and manufacturing of very thin 3D Hall probe heads, the design and manufacturing of coil sensors for the Rotating coil bench based on multilayered PCB, and the improvement of calibration methodology in order to improve the accuracy of the measurements. ALBA magnetic measurements laboratory is open for external contracts, and has been widely used by national and international institutes such as CERN, ESRF or CIEMAT, as well as magnet manufacturing companies, such as ANTEC, TESLA and I3 M. In this paper, we will present the main features of the measurement benches as well as improvements made so far.

An experimental study of permeability within an out-of-autoclave vacuum-bag-only CFRP laminate

NASA Astrophysics Data System (ADS)

Wallace, Landon F.

The out-of-autoclave vacuum-bag-only (OOA-VBO) manufacturing process is a process that eliminates an autoclave when manufacturing aerospace quality carbon fiber reinforced plastics (CFRP). OOA-VBO pre-impregnated resin tow systems rely on air channel networks that guide unwanted voids out of the laminate. The air path networks can be characterized by measuring the permeability of a pre-cured laminate. Permeability results were successfully obtained for a laminate with a compaction similar to that found in a typical vacuum bagging setup. A study was done to find the relationship between compaction of the laminate and permeability. Permeability was measured as the laminate cured, using a constant temperature ramp rate. An experimental nodal analysis was performed to find the permeability at the midpoint of the in-plane direction.

Permeability of sediment cores from methane hydrate deposit in the Eastern Nankai Trough, Japan

NASA Astrophysics Data System (ADS)

Konno, Y.; Yoneda, J.; Egawa, K.; Ito, T.; Jin, Y.; Kida, M.; Suzuki, K.; Nakatsuka, Y.; Nagao, J.

2013-12-01

Effective and absolute permeability are key parameters for gas production from methane-hydrate-bearing sandy sediments. Effective and/or absolute permeability have been measured using methane-hydrate-bearing sandy cores and clayey and silty cores recovered from Daini Atsumi Knoll in the Eastern Nankai Trough during the 2012 JOGMEC/JAPEX Pressure coring operation. Liquid-nitrogen-immersed cores were prepared by rapid depressurization of pressure cores recovered by a pressure coring system referred to as the Hybrid PCS. Cores were shaped cylindrically on a lathe with spraying of liquid nitrogen to prevent hydrate dissociation. Permeability was measured by a flooding test or a pressure relaxation method under near in-situ pressure and temperature conditions. Measured effective permeability of hydrate-bearing sediments is less than tens of md, which are order of magnitude less than absolute permeability. Absolute permeability of clayey cores is approximately tens of μd, which would perform a sealing function as cap rocks. Permeability reduction due to a swelling effect was observed for a silty core during flooding test of pure water mimicking hydrate-dissociation-water. Swelling effect may cause production formation damage especially at a later stage of gas production from methane hydrate deposits. This study was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) that carries out Japan's Methane Hydrate R&D Program conducted by the Ministry of Economy, Trade and Industry (METI).

Comparing Laboratory and Field Measured Bioaccumulation Endpoints

EPA Science Inventory

The report presents an approach that allows comparisons of all laboratory and field bioaccumulation endpoints measurements. The approach will enable the inclusion of large amounts of field data into evaluations of bioaccumulation potential for legacy chemicals. Currently, these...

Predicting A Drug'S Membrane Permeability: Evolution of a Computational Model Validated with in Vitro Permeability Assay Data

DOE PAGES

Carpenter, Timothy S.; McNerney, M. Windy; Be, Nicholas A.; ...

2016-02-16

Membrane permeability is a key property to consider in drug design, especially when the drugs in question need to cross the blood-brain barrier (BBB). A comprehensive in vivo assessment of the BBB permeability of a drug takes considerable time and financial resources. A current, simplified in vitro model to investigate drug permeability is a Parallel Artificial Membrane Permeability Assay (PAMPA) that generally provides higher throughput and initial quantification of a drug's passive permeability. Computational methods can also be used to predict drug permeability. Our methods are highly advantageous as they do not require the synthesis of the desired drug, andmore » can be implemented rapidly using high-performance computing. In this study, we have used umbrella sampling Molecular Dynamics (MD) methods to assess the passive permeability of a range of compounds through a lipid bilayer. Furthermore, the permeability of these compounds was comprehensively quantified using the PAMPA assay to calibrate and validate the MD methodology. And after demonstrating a firm correlation between the two approaches, we then implemented our MD method to quantitatively predict the most permeable potential drug from a series of potential scaffolds. This permeability was then confirmed by the in vitro PAMPA methodology. Therefore, in this work we have illustrated the potential that these computational methods hold as useful tools to help predict a drug's permeability in a faster and more cost-effective manner. Release number: LLNL-ABS-677757.« less

Predicting A Drug'S Membrane Permeability: Evolution of a Computational Model Validated with in Vitro Permeability Assay Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpenter, Timothy S.; McNerney, M. Windy; Be, Nicholas A.

Membrane permeability is a key property to consider in drug design, especially when the drugs in question need to cross the blood-brain barrier (BBB). A comprehensive in vivo assessment of the BBB permeability of a drug takes considerable time and financial resources. A current, simplified in vitro model to investigate drug permeability is a Parallel Artificial Membrane Permeability Assay (PAMPA) that generally provides higher throughput and initial quantification of a drug's passive permeability. Computational methods can also be used to predict drug permeability. Our methods are highly advantageous as they do not require the synthesis of the desired drug, andmore » can be implemented rapidly using high-performance computing. In this study, we have used umbrella sampling Molecular Dynamics (MD) methods to assess the passive permeability of a range of compounds through a lipid bilayer. Furthermore, the permeability of these compounds was comprehensively quantified using the PAMPA assay to calibrate and validate the MD methodology. And after demonstrating a firm correlation between the two approaches, we then implemented our MD method to quantitatively predict the most permeable potential drug from a series of potential scaffolds. This permeability was then confirmed by the in vitro PAMPA methodology. Therefore, in this work we have illustrated the potential that these computational methods hold as useful tools to help predict a drug's permeability in a faster and more cost-effective manner. Release number: LLNL-ABS-677757.« less

Data report: Permeabilities of eastern equatorial Pacific and Peru margin sediments

USGS Publications Warehouse

Gamage, Kusali; Bekins, Barbara A.; Screaton, Elizabeth; Jørgensen, Bo B.; D'Hondt, Steven L.; Miller, D. Jay

2006-01-01

Constant-flow permeability tests were conducted on core samples from Ocean Drilling Program Leg 201 from the eastern equatorial Pacific and the Peru margin. Eighteen whole-round core samples from Sites 1225, 1226, 1227, 1230, and 1231 were tested for vertical permeabilities. Sites 1225, 1226, and 1231 represent sediments of the open ocean, whereas Sites 1227 and 1230 represent sediments of the ocean margin. Measured vertical permeabilities vary from ~8 x 10–19 m2 to ~1 x 10–16 m2 for a porosity range of 45%–90%.

Long-term stormwater quantity and quality performance of permeable pavement systems.

PubMed

Brattebo, Benjamin O; Booth, Derek B

2003-11-01

This study examined the long-term effectiveness of permeable pavement as an alternative to traditional impervious asphalt pavement in a parking area. Four commercially available permeable pavement systems were evaluated after 6 years of daily parking usage for structural durability, ability to infiltrate precipitation, and impacts on infiltrate water quality. All four permeable pavement systems showed no major signs of wear. Virtually all rainwater infiltrated through the permeable pavements, with almost no surface runoff. The infiltrated water had significantly lower levels of copper and zinc than the direct surface runoff from the asphalt area. Motor oil was detected in 89% of samples from the asphalt runoff but not in any water sample infiltrated through the permeable pavement. Neither lead nor diesel fuel were detected in any sample. Infiltrate measured 5 years earlier displayed significantly higher concentrations of zinc and significantly lower concentrations of copper and lead.

Laboratory measurements of gravel thermal properties. A methodology proposal

NASA Astrophysics Data System (ADS)

Cultrera, Matteo; Peron, Fabio; Bison, Paolo; Dalla Santa, Giorgia; Bertermann, David; Muller, Johannes; Bernardi, Adriana; Galgaro, Antonio

2017-04-01

Gravel thermal properties measurements at laboratory level is quite challenging due to several technical and logistic issues, mainly connected to the sediment sizes and the variability of their mineralogical composition. The direct measurement of gravel thermal properties usually are not able to involve a representative volume of geological material, consequently the thermal measurements performed produce much dispersed results and not consistent due to the large interstitial voids and the poor physical contact with the measuring sensors. With the aim of directly provide the measurement of the gravel thermal properties, a new methodology has been developed and some results are already available on several gravel deposits samples around Europe. Indeed, a single guarded hot plate Taurus Instruments TLP 800 measured the gravel thermal properties. Some instrumental adjustments were necessary to adapt the measuring devices and to finalize the thermal measurements on gravels at the IUAV FISTEC laboratory (Environmental Technical Physics Laboratory of Venice University). This device usually provides thermal measurements according to ISO 8302, ASTM C177, EN 1946-2, EN 12664, EN 12667 and EN 12939 for building materials. A preliminary calibration has been performed comparing the outcomes obtained with the single guarded hot plate with a needle probe of a portable thermal conductivity meter (ISOMET). Standard sand (ISO 67:2009) is used as reference material. This study is provided under the Cheap-GSHPs project that has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement no. 657982

Stable room temperature magnetocurrent in electrodeposited permeable n-type metal base transistor

NASA Astrophysics Data System (ADS)

Silva, G. V. O.; Teixeira, H. A.; Mello, S. L. A.; de Araujo, C. I. L.

2018-02-01

We investigated a permeable metal base transistor consisting of a ZnO/NiFe/Si heterostructure. Both ZnO and NiFe layers were grown by electrodeposition techniques, using only adhesive tape masks to define deposition regions. The base permeability can thus be controlled by varying the NiFe deposition time. We report here our best results obtained for the permeable NiFe base close to the electrical percolation threshold, which gives reasonable sensitivity to the device. Magnetocurrent measurements carried out at room temperature show that this permeable metal base transistor is stable and sensitive under applied magnetic fields of low intensities, ˜100 Oe, required for electronics integration.

The effect of conductor permeability on electric current transducers

NASA Astrophysics Data System (ADS)

Mirzaei, M.; Ripka, P.; Chirtsov, A.; Kaspar, P.; Vyhnanek, J.

2018-04-01

In this paper, experimental works and theoretical analysis are presented to analyze the influence of the conductor permeability on the precision of yokeless current sensors. The results of finite-element method (FEM) fit well the measured field values around the conductor. Finally we evaluate the difference in magnetic fields distribution around non-magnetic and magnetic conductor. The calculated values show that the permeability of the ferromagnetic conductor significally affects the reading of the electric current sensors even at DC.

Fluid flow and permeabilities in basement fault zones

NASA Astrophysics Data System (ADS)

Hollinsworth, Allan; Koehn, Daniel

2017-04-01

Fault zones are important sites for crustal fluid flow, specifically where they cross-cut low permeability host rocks such as granites and gneisses. Fluids migrating through fault zones can cause rheology changes, mineral precipitation and pore space closure, and may alter the physical and chemical properties of the host rock and deformation products. It is therefore essential to consider the evolution of permeability in fault zones at a range of pressure-temperature conditions to understand fluid migration throughout a fault's history, and how fluid-rock interaction modifies permeability and rheological characteristics. Field localities in the Rwenzori Mountains, western Uganda and the Outer Hebrides, north-west Scotland, have been selected for field work and sample collection. Here Archaean-age TTG gneisses have been faulted within the upper 15km of the crust and have experienced fluid ingress. The Rwenzori Mountains are an anomalously uplifted horst-block located in a transfer zone in the western rift of the East African Rift System. The north-western ridge is characterised by a tectonically simple western flank, where the partially mineralised Bwamba Fault has detached from the Congo craton. Mineralisation is associated with hydrothermal fluids heated by a thermal body beneath the Semliki rift, and has resulted in substantial iron oxide precipitation within porous cataclasites. Non-mineralised faults further north contain foliated gouges and show evidence of leaking fluids. These faults serve as an analogue for faults associated with the Lake Albert oil and gas prospects. The Outer Hebrides Fault Zone (OHFZ) was largely active during the Caledonian Orogeny (ca. 430-400 Ma) at a deeper crustal level than the Ugandan rift faults. Initial dry conditions were followed by fluid ingress during deformation that controlled its rheological behaviour. The transition also altered the existing permeability. The OHFZ is a natural laboratory in which to study brittle fault

Effect of a new desensitizing material on human dentin permeability.

PubMed

Rusin, Richard P; Agee, Kelli; Suchko, Michael; Pashley, David H

2010-06-01

Resin-modified glass ionomers (RMGI) have demonstrated clinical success providing immediate and long-term relief from root sensitivity. RMGIs have been recently introduced as paste-liquid systems for convenience of clinical usage. The objective of this study was to measure the ability of a new paste-liquid RMGI to reduce fluid flow through human dentin, compared to an established single-bottle nanofilled total etch resin adhesive indicated for root desensitization. Dentin permeability was measured on human crown sections on etched dentin, presenting a model for the exposed tubules typical of root sensitivity, and permitting measurement of the maximum permeability. In the first two groups, the etched dentin was coated with either the RMGI or adhesive, and permeability measured on the coated dentin. In a third group, a smear layer was created on the dentin with sandpaper, then the specimens were coated with the RMGI; permeability was measured on the smeared and coated dentin. Specimens from each group were sectioned and examined via scanning electron microscopy (SEM). Both the resin adhesive and the new paste-liquid RMGI protective material significantly reduced fluid flow through dentin, and exhibited excellent seal on dentin with either open tubules or smear-layer occluded tubules. The RMGI infiltrated the smear layer with resin during placement, penetrated dentin tubules, and formed resin tags. The RMGI was equivalent to the adhesive in its ability to reduce fluid flow and seal dentin. It is therefore concluded that the new RMGI and the adhesive show the potential to offer excellent sensitivity relief on exposed root dentin. Copyright (c) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Proficiency Tests for Environmental Radioactivity Measurement Organized by an Accredited Laboratory

NASA Astrophysics Data System (ADS)

Aubert, Cédric; Osmond, Mélanie

2008-08-01

For 40 years, STEME (Environmental Sample Processing and Metrology Department) organized international proficiency testing (PT) exercises formerly for WHO (World Health Organization) and EC (European Community) and currently for ASN (French Nuclear Safety Authority). Five PT exercises are organized each year for the measurement of radionuclides (alpha, beta and gamma) in different matrixes (water, soil, biological and air samples) at environmental levels. ASN can deliver a French ministerial agreement to participate on environmental radioactivity measurements French network for laboratories asking it [1]. Since 2006, November, STEME is the first French entity obtaining a COFRAC (French Committee of Accreditation) accreditation as "Interlaboratory Comparisons" for the organization of proficiency tests for environmental radioactivity measurement according to standard International Standard Organization (ISO) 17025 and guide ISO 43-1. STEME has in charge to find, as far as possible, real sample or to create, by radionuclide adding, an adapted sample. STEME realizes the sampling, the samples preparation and the dispatching. STEME is also accredited according to Standard 17025 for radioactivity measurements in environmental samples and determines homogeneity, stability and reference values. After the reception of participating laboratories results, STEME executes statistical treatments in order to verify the normal distribution, to eliminate outliers and to evaluate laboratories performance. Laboratories participate with several objectives, to obtain French agreement, to prove the quality of their analytical performance in regards to standard 17025 or to validate new methods or latest developments. For 2 years, in addition to usual PT exercises, new PT about alpha or beta measurement in air filters, radioactive iodine in carbon cartridges or measurement of environmental dosimeters are organized. These PT exercises help laboratories to improve radioactive measurements

Proficiency Tests for Environmental Radioactivity Measurement Organized by an Accredited Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubert, Cedric; Osmond, Melanie

2008-08-14

For 40 years, STEME (Environmental Sample Processing and Metrology Department) organized international proficiency testing (PT) exercises formerly for WHO (World Health Organization) and EC (European Community) and currently for ASN (French Nuclear Safety Authority). Five PT exercises are organized each year for the measurement of radionuclides (alpha, beta and gamma) in different matrixes (water, soil, biological and air samples) at environmental levels. ASN can deliver a French ministerial agreement to participate on environmental radioactivity measurements French network for laboratories asking it. Since 2006, November, STEME is the first French entity obtaining a COFRAC (French Committee of Accreditation) accreditation as 'Interlaboratorymore » Comparisons' for the organization of proficiency tests for environmental radioactivity measurement according to standard International Standard Organization (ISO) 17025 and guide ISO 43-1. STEME has in charge to find, as far as possible, real sample or to create, by radionuclide adding, an adapted sample. STEME realizes the sampling, the samples preparation and the dispatching. STEME is also accredited according to Standard 17025 for radioactivity measurements in environmental samples and determines homogeneity, stability and reference values. After the reception of participating laboratories results, STEME executes statistical treatments in order to verify the normal distribution, to eliminate outliers and to evaluate laboratories performance.Laboratories participate with several objectives, to obtain French agreement, to prove the quality of their analytical performance in regards to standard 17025 or to validate new methods or latest developments. For 2 years, in addition to usual PT exercises, new PT about alpha or beta measurement in air filters, radioactive iodine in carbon cartridges or measurement of environmental dosimeters are organized. These PT exercises help laboratories to improve radioactive measurements

Use of O-15 water and C-11 butanol to measure cerebral blood flow (CBF) and water permeability with positron emission tomography (PET)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herscovitch, P.; Raichle, M.E.; Kilbourn, M.R.

1985-05-01

Tracers used to measure CBF with PET and the Kety autoradiographic approach should freely cross the blood-brain barrier. 0-15 water, which is not freely permeable, may underestimate CBF, especially at higher flows. The authors determined this under-estimation relative to flow measured with a freely diffusible tracer, C-11 butanol and used these data to calculate the extraction (E) and permeability surface area product (PS) for 0-15 water. Paired flow measurements were made with 0-15 water (CBF-wat) and C-11 butanol (CBF-but) in eight normal human subjects. Average CBF-but, 55.6 ml/(min . 100g) was significantly greater than CBF-water, 47.6 ml/(min . 100g). Themore » ratio of regional gray matter (GM) flow to white matter (WM) flow was significantly greater with C-11 butanol, indicating a greater underestimation of CBF with 0-15 water in the higher flow GM. Average E for water was 0.92 in WM and 0.82 in GM. The mean PS in GM, 148 ml/(min . 100g), was significantly greater than in WM, 94 ml/(min . 100g). Simulation studies demonstrated that a measurement error in CBF-wat or CBF-but causes an approximately equivalent error in E but a considerably larger error in PS due to the sensitivity of the equation, PS=-CBF . ln(1-E), to variations in E. Modest errors in E and PS result from tissue heterogeneity that occurs due to the limited spatial resolution of PET. The authors' measurements of E and PS for water are similar to data obtained by more invasive methods and demonstrate the ability of PET to measure brain water permeability.« less

Microwave moisture measurement of cotton fiber moisture content in the laboratory

USDA-ARS?s Scientific Manuscript database

The moisture content of cotton fiber is an important fiber property, but it is often measured by a laborious, time-consuming laboratory oven drying method. A program was implemented to establish the capabilities of a laboratory microwave moisture measurement instrument to perform rapid, precise and...

Human Disc Nucleus Properties and Vertebral Endplate Permeability

PubMed Central

Rodriguez, Azucena G.; Slichter, Chloe K.; Acosta, Frank L.; Rodriguez-Soto, Ana E.; Burghardt, Andrew J.; Majumdar, Sharmila; Lotz, Jeffrey C.

2010-01-01

Study of human cadaveric discs quantifying endplate permeability and porosity and correlating these with measures of disc quality: cell density, proteoglycan content, and overall degeneration. Permeability and porosity increased with age and were not correlated with cell density or overall degeneration, suggesting that endplate calcification may not accelerate disc degeneration. Study Design Experimental quantification of relationships between vertebral endplate morphology, permeability, disc cell density, glycosaminoglycan content and degeneration in samples harvested from human cadaveric spines. Objective To test the hypothesis that variation in endplate permeability and porosity contribute to changes in intervertebral disc cell density and overall degeneration. Summary of Background Data Cells within the intervertebral disc are dependent on diffusive exchange with capillaries in the adjacent vertebral bone. Previous findings suggest that blocked routes of transport negatively affect disc quality, yet there are no quantitative relationships between human vertebral endplate permeability, porosity, cell density and disc degeneration. Such relationships would be valuable for clarifying degeneration risk factors, and patient features that may impede efforts at disc tissue engineering. Methods Fifty-one motion segments were harvested from 13 frozen cadaveric human lumbar spines (32 to 85 years) and classified for degeneration using the MRI-based Pfirrmann scale. A cylindrical core was harvested from the center of each motion segment that included vertebral bony and cartilage endplates along with adjacent nucleus tissue. The endplate mobility, a type of permeability, was measured directly using a custom-made permeameter before and after the cartilage endplate was removed. Cell density within the nucleus tissue was estimated using the picogreen method while the nuclear GAG content was quantified using the DMMB technique. Specimens were imaged at 8 μm resolution using

Radon Mitigation Approach in a Laboratory Measurement Room

PubMed Central

Blanco-Rodríguez, Patricia; Fernández-Serantes, Luis Alfonso; Otero-Pazos, Alberto; Calvo-Rolle, José Luis; de Cos Juez, Francisco Javier

2017-01-01

Radon gas is the second leading cause of lung cancer, causing thousands of deaths annually. It can be a problem for people or animals in houses, workplaces, schools or any building. Therefore, its mitigation has become essential to avoid health problems and to prevent radon from interfering in radioactive measurements. This study describes the implementation of radon mitigation systems at a radioactivity laboratory in order to reduce interferences in the different works carried out. A large set of radon concentration samples is obtained from measurements at the laboratory. While several mitigation methods were taken into account, the final applied solution is explained in detail, obtaining thus very good results by reducing the radon concentration by 76%. PMID:28492468

Radon Mitigation Approach in a Laboratory Measurement Room.

PubMed

Blanco-Rodríguez, Patricia; Fernández-Serantes, Luis Alfonso; Otero-Pazos, Alberto; Calvo-Rolle, José Luis; de Cos Juez, Francisco Javier

2017-05-11

Radon gas is the second leading cause of lung cancer, causing thousands of deaths annually. It can be a problem for people or animals in houses, workplaces, schools or any building. Therefore, its mitigation has become essential to avoid health problems and to prevent radon from interfering in radioactive measurements. This study describes the implementation of radon mitigation systems at a radioactivity laboratory in order to reduce interferences in the different works carried out. A large set of radon concentration samples is obtained from measurements at the laboratory. While several mitigation methods were taken into account, the final applied solution is explained in detail, obtaining thus very good results by reducing the radon concentration by 76%.

Permeability of soils in Mississippi

USGS Publications Warehouse

O'Hara, Charles G.

1994-01-01

The permeability of soils in Mississippi was determined and mapped using a geographic information system (GIS). Soil permeabilities in Mississippi were determined to range in value from nearly 0.0 to values exceeding 5.0 inches per hour. The U.S. Soil Conservation Service's State Soil Geographic Data Base (STATSGO) was used as the primary source of data for the determination of area-weighted soil permeability. STATSGO provides soil layer properties that are spatially referenced to mapped areas. These mapped areas are referred to as polygons in the GIS. The polygons arc boundaries of soils mapped as a group and are given unique Map Unit Identifiers (MUIDs). The data describing the physical characteristics of the soils within each polygon are stored in a tabular data base format and are referred to as attributes. The U.S. Soil Conservation Service developed STATSGO to be primarily used as a guide for regional resource planning, management, and monitoring. STATSGO was designed so that soil information could be extracted from properties tables at the layer level, combined by component, and statistically expanded to cover the entire map unit. The results of this study provide a mapped value for permeability which is representative of the vertical permeability of soils in that area. The resultant permeability map provides a representative vertical soil permeability for a given area sufficient for county, multi- county, and area planning, and will be used as the soil permeability data component in the evaluation of the susceptibility of major aquifers to contami- nation in Mississippi.

EPA Permeable Surface Research

EPA Science Inventory

EPA recognizes permeable surfaces as an effective post-construction infiltration-based Best Management Practice to mitigate the adverse effects of stormwater runoff. The professional user community conceptually embraces permeable surfaces as a tool for making runoff more closely...

Highly predictive and interpretable models for PAMPA permeability.

PubMed

Sun, Hongmao; Nguyen, Kimloan; Kerns, Edward; Yan, Zhengyin; Yu, Kyeong Ri; Shah, Pranav; Jadhav, Ajit; Xu, Xin

2017-02-01

Cell membrane permeability is an important determinant for oral absorption and bioavailability of a drug molecule. An in silico model predicting drug permeability is described, which is built based on a large permeability dataset of 7488 compound entries or 5435 structurally unique molecules measured by the same lab using parallel artificial membrane permeability assay (PAMPA). On the basis of customized molecular descriptors, the support vector regression (SVR) model trained with 4071 compounds with quantitative data is able to predict the remaining 1364 compounds with the qualitative data with an area under the curve of receiver operating characteristic (AUC-ROC) of 0.90. The support vector classification (SVC) model trained with half of the whole dataset comprised of both the quantitative and the qualitative data produced accurate predictions to the remaining data with the AUC-ROC of 0.88. The results suggest that the developed SVR model is highly predictive and provides medicinal chemists a useful in silico tool to facilitate design and synthesis of novel compounds with optimal drug-like properties, and thus accelerate the lead optimization in drug discovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

A method for developing outcome measures in the clinical laboratory.

PubMed

Jones, J

1996-01-01

Measuring and reporting outcomes in health care is becoming more important for quality assessment, utilization assessment, accreditation standards, and negotiating contracts in managed care. How does one develop an outcome measure for the laboratory to assess the value of the services? A method is described which outlines seven steps in developing outcome measures for a laboratory service or process. These steps include the following: 1. Identify the process or service to be monitored for performance and outcome assessment. 2. If necessary, form an multidisciplinary team of laboratory staff, other department staff, physicians, and pathologists. 3. State the purpose of the test or service including a review of published data for the clinical pathological correlation. 4. Prepare a process cause and effect diagram including steps critical to the outcome. 5. Identify key process variables that contribute to positive or negative outcomes. 6. Identify outcome measures that are not process measures. 7. Develop an operational definition, identify data sources, and collect data. Examples, including a process cause and effect diagram, process variables, and outcome measures, are given using the Therapeutic Drug Monitoring service (TDM). A summary of conclusions and precautions for outcome measurement is then provided.

Determination of hydrogen permeability in commercial and modified superalloys

NASA Technical Reports Server (NTRS)

Bhattacharyya, S.; Peterman, W.

1983-01-01

The results of hydrogen permeability measurements on several iron- and cobalt-base alloys as well as on two long-ranged ordered alloys over the range of 705 to 870 C (1300 to 1600 F) are summarized. The test alloys included wrought alloys N-155, IN 800, A-286, 19-9DL, and 19-9DL modifications with aluminum, niobium, and misch metal. In addition, XF-818, CRM-6D, SA-F11, and HS-31 were evaluated. Two wrought long-range ordered alloys, Ni3Al and (Fe,Ni)3(V,Al) were also evaluated. All tests were conducted at 20.7 MPa pressure in either pure and/or 1% CO2-doped H2 for test periods as long as 133 h. Detailed analyses were conducted to determine the relative permeability rankings of these alloys and the effect of doping, exit surface oxidation, specimen design variations, and test duration on permeability coefficient, and permeation activation energies were determined. The two long-range ordered alloys had the lowest permeability coefficients in pure H2 when compared with the eight commercial alloys and their modifications. With CO2 doping, significant decrease in permeability was observed in commercial alloys--no doped tests were conducted with the long-range ordered alloys.

Monitoring Single-channel Water Permeability in Polarized Cells*

PubMed Central

Erokhova, Liudmila; Horner, Andreas; Kügler, Philipp; Pohl, Peter

2011-01-01

So far the determination of unitary permeability (pf) of water channels that are expressed in polarized cells is subject to large errors because the opening of a single water channel does not noticeably increase the water permeability of a membrane patch above the background. That is, in contrast to the patch clamp technique, where the single ion channel conductance may be derived from a single experiment, two experiments separated in time and/or space are required to obtain the single-channel water permeability pf as a function of the incremental water permeability (Pf,c) and the number (n) of water channels that contributed to Pf,c. Although the unitary conductance of ion channels is measured in the native environment of the channel, pf is so far derived from reconstituted channels or channels expressed in oocytes. To determine the pf of channels from live epithelial monolayers, we exploit the fact that osmotic volume flow alters the concentration of aqueous reporter dyes adjacent to the epithelia. We measure these changes by fluorescence correlation spectroscopy, which allows the calculation of both Pf,c and osmolyte dilution within the unstirred layer. Shifting the focus of the laser from the aqueous solution to the apical and basolateral membranes allowed the FCS-based determination of n. Here we validate the new technique by determining the pf of aquaporin 5 in Madin-Darby canine kidney cell monolayers. Because inhibition and subsequent activity rescue are monitored on the same sample, drug effects on exocytosis or endocytosis can be dissected from those on pf. PMID:21940624

Measuring dynamic kidney function in an undergraduate physiology laboratory.

PubMed

Medler, Scott; Harrington, Frederick

2013-12-01

Most undergraduate physiology laboratories are very limited in how they treat renal physiology. It is common to find teaching laboratories equipped with the capability for high-resolution digital recordings of physiological functions (muscle twitches, ECG, action potentials, respiratory responses, etc.), but most urinary laboratories still rely on a "dipstick" approach of urinalysis. Although this technique can provide some basic insights into the functioning of the kidneys, it overlooks the dynamic processes of filtration, reabsorption, and secretion. In the present article, we provide a straightforward approach of using renal clearance measurements to estimate glomerular filtration rate, fractional water reabsorption, glucose clearance, and other physiologically relevant parameters. The estimated values from our measurements in laboratory are in close agreement with those anticipated based on textbook parameters. For example, we found glomerular filtration rate to average 124 ± 45 ml/min, serum creatinine to be 1.23 ± 0.4 mg/dl, and fractional water reabsorption to be ∼96.8%. Furthermore, analyses for the class data revealed significant correlations between parameters like fractional water reabsorption and urine concentration, providing opportunities to discuss urine concentrating mechanisms and other physiological processes. The procedures outlined here are general enough that most undergraduate physiology laboratory courses should be able to implement them without difficulty.

Regulation of Epithelial Cell Permeability by Nanostructured Thin Films

NASA Astrophysics Data System (ADS)

Stewart, Tarianna V.

Epithelia form barriers that regulate the movement of water, ions and molecules from one part of an organ to another. Facilitated transepithelial transport is important to enable drug delivery. Using human colon carcinoma (Caco-2) epithelial cells as a model, I found that contact with patterned nanostructured films (NSFs) enhanced the transepithelial transport of several different macromolecules without using chemical permeation agents. To determine the maximum paracellular permeability through tight junctions (TJs) I modified a calcium-"switch" model, as measured by the diffusion rate for all of the probes examined when media was changed from standard (20 mM) to low (10 microM) calcium. I then compared the permeability of Caco-2 cells in contact with NSFs to the maximum paracellular permeability of cells without NSFs at baseline. Caco-2 cells stimulated with NSFs showed an enhanced level of apical to basolateral transport for intact IgG compared to maximum paracellular permeability. However for the other probes examined, the paracellular permeability induced by NSFs was less than the maximum paracellular permeability of cells. These findings suggest that Caco-2 cells in contact with NSFs induce the specific, active transport of IgG from the apical to the basolateral cell surface of the epithelium. A series of experiments demonstrated the presence of so-called "neonatal" Fc receptors (FcRn) in Caco-2 cells and that these mediated the transcytosis of IgG across the cells. Moreover, contact with NSFs also enhanced paracellular transport, as determined by changes in TJ morphology and decreased transepithelial resistance (TER). To better understand the effects of NSFs on paracellular transport, we measured changes in matrix-metalloendoprotease (MMP) expression and activity was examined. MMP-2 and MMP-9 were upregulated by contact with NSFs. Roles for MMPs in regulating the effects of NSFs on epithelial cells are discussed. Thus, NSFs specifically enhance the

Temperature dependence dynamical permeability characterization of magnetic thin film using near-field microwave microscopy

NASA Astrophysics Data System (ADS)

Hung, Le Thanh; Phuoc, Nguyen N.; Wang, Xuan-Cong; Ong, C. K.

2011-08-01

A temperature dependence characterization system of microwave permeability of magnetic thin film up to 5 GHz in the temperature range from room temperature up to 423 K is designed and fabricated as a prototype measurement fixture. It is based on the near field microwave microscopy technique (NFMM). The scaling coefficient of the fixture can be determined by (i) calibrating the NFMM with a standard sample whose permeability is known; (ii) by calibrating the NFMM with an established dynamic permeability measurement technique such as shorted microstrip transmission line perturbation method; (iii) adjusting the real part of the complex permeability at low frequency to fit the value of initial permeability. The algorithms for calculating the complex permeability of magnetic thin films are analyzed. A 100 nm thick FeTaN thin film deposited on Si substrate by sputtering method is characterized using the fixture. The room temperature permeability results of the FeTaN film agree well with results obtained from the established short-circuited microstrip perturbation method. Temperature dependence permeability results fit well with the Landau-Lifshitz-Gilbert equation. The temperature dependence of the static magnetic anisotropy H_K^{sta}, the dynamic magnetic anisotropy H_K^{dyn}, the rotational anisotropy Hrot, together with the effective damping coefficient αeff, ferromagnetic resonance fFMR, and frequency linewidth Δf of the thin film are investigated. These temperature dependent magnetic properties of the magnetic thin film are important to the high frequency applications of magnetic devices at high temperatures.

Localized Versus Distributed Deformation as a Control on the Evolution of Permeability in Anhydrite Rocks

NASA Astrophysics Data System (ADS)

Collettini, C.; de Paola, N.; Faulkner, D.

2007-12-01

We have taken an experimental approach to understand and quantify the deformation processes and fluid flow within anhydrite-bearing fault damage zones during the seismic cycle. Triaxial loading tests have been performed on borehole samples of anhydrites at room temperature, 100 MPa confining pressure (Pc), and range of pore fluid pressures (Pf). Permeability and porosity development was continuously measured throughout the deformation experiments. The tests were conducted on samples with different grain sizes (10 microns to 1 mm) that were cored in different directions relative to the macroscopic foliation. Static permeability measurements have been carried out to determine the permeability anisotropy and sensitivity of the permeability on the effective pressure (Pc - Pf). Our results show that the brittle-ductile transition occurs for effective pressures (Pe) between 20 to 40 MPa and is almost independent of fabric orientation and grain size. Brittle failure is localized along discrete fractures and is always associated with a sudden stress drop. Conversely, ductile failure occurs by distributed deformation along cataclastic bands. In this case no stress drop is observed. Static permeability measurements show increasing values of permeability for decreasing values of Pe, (k = 10E-20 - 10E-22 m2). During single cycle loading tests, the evolution of the permeability is controlled by the failure mode: permeability begins to increase significantly at 40% and 80% of the max load for samples displaying brittle and ductile behaviour, respectively. The permeability values, immediately prior to failure, are about three orders of magnitude higher than the initial values. Multiple cycling tests, within the ductile field, show that permeability starts increasing at only 40% and 30% of the max load during the second and third loading cycle, respectively. Our results show that the history of deformation and the mode of deformation can control the evolution of the permeability

The effect of stress on limestone permeability and its effective stress behavior

NASA Astrophysics Data System (ADS)

Meng, F.; Baud, P.; Ge, H.; Wong, T. F.

2017-12-01

The evolution of permeability and its effective stress behavior is related to inelastic deformation and failure mode. This was investigated in Indiana and Purbeck limestones with porosities of 18% and 13%, respectively. Hydrostatic and triaxial compression tests were conducted at room temperature on water-saturated samples at pore pressure of 5 MPa and confining pressures up to 90 MPa. Permeability was measured using steady flow at different stages of deformation. For Indiana limestone, under hydrostatic loading pore collapse initiated at critical pressure P* 55 MPa with an accelerated reduction of permeability by 1/2. At a confinement of 35 MPa and above, shear-enhanced compaction initiated at critical stress C*, beyond which permeability reduction up to a factor of 3 was observed. At a confinement of 15 MPa and below, dilatancy initiated at critical stress C', beyond which permeability continued to decrease, with a negative correlation between porosity and permeability changes. Purbeck limestone showed similar evolution of permeability. Microstructural and mercury porosimetry data showed that pore size distribution in both Indiana and Purbeck limestones is bimodal, with significant proportions of macropores and micropores. The effective stress behaviour of a limestone with dual porosity is different from the prediction for a microscopically homogeneous assemblage, in that its effective stress coefficients for permeability and porosity change may attain values significantly >1. Indeed this was confirmed by our measurements (at confining pressures of 7-15 MPa and pore pressures of 1-3 MPa) in samples that had not been deformed inelastically. We also investigated the behavior in samples hydrostatically and triaxially compacted to beyond the critical stresses P* and C*, respectively. Experimental data for these samples consistently showed effective stress coefficients for both permeability and porosity change with values <1. Thus the effective stress behavior in an

Effects of free convection and friction on heat-pulse flowmeter measurement

NASA Astrophysics Data System (ADS)

Lee, Tsai-Ping; Chia, Yeeping; Chen, Jiun-Szu; Chen, Hongey; Liu, Chen-Wuing

2012-03-01

SummaryHeat-pulse flowmeter can be used to measure low flow velocities in a borehole; however, bias in the results due to measurement error is often encountered. A carefully designed water circulation system was established in the laboratory to evaluate the accuracy and precision of flow velocity measured by heat-pulse flowmeter in various conditions. Test results indicated that the coefficient of variation for repeated measurements, ranging from 0.4% to 5.8%, tends to increase with flow velocity. The measurement error increases from 4.6% to 94.4% as the average flow velocity decreases from 1.37 cm/s to 0.18 cm/s. We found that the error resulted primarily from free convection and frictional loss. Free convection plays an important role in heat transport at low flow velocities. Frictional effect varies with the position of measurement and geometric shape of the inlet and flow-through cell of the flowmeter. Based on the laboratory test data, a calibration equation for the measured flow velocity was derived by the least-squares regression analysis. When the flowmeter is used with a diverter, the range of measured flow velocity can be extended, but the measurement error and the coefficient of variation due to friction increase significantly. At higher velocities under turbulent flow conditions, the measurement error is greater than 100%. Our laboratory experimental results suggested that, to avoid a large error, the heat-pulse flowmeter measurement is better conducted in laminar flow and the effect of free convection should be eliminated at any flow velocities. Field measurement of the vertical flow velocity using the heat-pulse flowmeter was tested in a monitoring well. The calibration of measured velocities not only improved the contrast in hydraulic conductivity between permeable and less permeable layers, but also corrected the inconsistency between the pumping rate and the measured flow rate. We identified two highly permeable sections where the horizontal

Achieving continuous improvement in laboratory organization through performance measurements: a seven-year experience.

PubMed

Salinas, Maria; López-Garrigós, Maite; Gutiérrez, Mercedes; Lugo, Javier; Sirvent, Jose Vicente; Uris, Joaquin

2010-01-01

Laboratory performance can be measured using a set of model key performance indicators (KPIs). The design and implementation of KPIs are important issues. KPI results from 7 years are reported and their implementation, monitoring, objectives, interventions, result reporting and delivery are analyzed. The KPIs of the entire laboratory process were obtained using Laboratory Information System (LIS) registers. These were collected automatically using a data warehouse application, spreadsheets and external quality program reports. Customer satisfaction was assessed using surveys. Nine model laboratory KPIs were proposed and measured. The results of some examples of KPIs used in our laboratory are reported. Their corrective measurements or the implementation of objectives led to improvement in the associated KPIs results. Measurement of laboratory performance using KPIs and a data warehouse application that continuously collects registers and calculates KPIs confirmed the reliability of indicators, indicator acceptability and usability for users, and continuous process improvement.

An Experimental Study on Characterization of Physical Properties of Ultramafic Rocks and Controls on Evolution of Fracture Permeability During Serpentinization at Hydrothermal Conditions

NASA Astrophysics Data System (ADS)

Farough, Aida

Serpentinization is a complex set of hydration reactions, where olivine and pyroxene are replaced by serpentine, magnetite, brucite, talc and carbonate minerals. Serpentinization reactions alter chemical, mechanical, magnetic, seismic, and hydraulic properties of the crust. To understand the complicated nature of serpentinization and the linkages between physical and chemical changes during the reactions, I performed flow-through laboratory experiments on cylindrically cored samples of ultramafic rocks. Each core had a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at an effective pressure of 30 MPa, and temperature of 260"aC, simulating a depth of 2 km under hydrostatic conditions. Fracture permeability decreased by one to two orders of magnitude during the 200 to 340 hour experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferromagnesian minerals. The rate of transformation of olivine to serpentine in a tensile fracture is calculated using the data on evolution of fracture permeability assuming the fracture permeability could be represented by parallel plates. Assuming the dissolution and precipitation reactions occur simultaneously; the rate of transformation at the beginning of the experiments was 10-8-10-9 (mol/m2s) and decreased monotonically by about an order of magnitude towards the end of the experiment. Results show that dissolution and precipitation is the main mechanism contributing to the reduction in fracture aperture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems may be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of

Vortex rings impinging on permeable boundaries

NASA Astrophysics Data System (ADS)

Mujal-Colilles, Anna; Dalziel, Stuart B.; Bateman, Allen

2015-01-01

Experiments with vortex rings impinging permeable and solid boundaries are presented in order to investigate the influence of permeability. Utilizing Particle Image Velocimetry, we compared the behaviour of a vortex ring impinging four different reticulated foams (with permeability k ˜ 26 - 85 × 10-8 m2) and a solid boundary. Results show how permeability affects the stretching phenomena of the vortex ring and the formation and evolution of the secondary vortex ring with opposite sign. Moreover, permeability also affects the macroscopic no-slip boundary condition found on the solid boundary, turning it into an apparent slip boundary condition for the most permeable boundary. The apparent slip-boundary condition and the flux exchange between the ambient fluid and the foam are jointly responsible for both the modified formation of the secondary vortex and changes on the vortex ring diameter increase.

Film Permeability Determination Using Static Permeability Cells

EPA Pesticide Factsheets

The permeability of tarps to soil fumigant pesticides varies depending on the active ingredient chemical: dimethyl disulfide (DMDS), methyl bromide, chloropicrin, or other. The diffusion rate can be represented by the mass transfer coefficient (MTC).

Corticosterone mediates stress-related increased intestinal permeability in a region-specific manner

PubMed Central

Zheng, Gen; Wu, Shu-Pei; Hu, Yongjun; Smith, David E; Wiley, John W.; Hong, Shuangsong

2012-01-01

Background Chronic psychological stress (CPS) is associated with increased intestinal epithelial permeability and visceral hyperalgesia. It is unknown whether corticosterone (CORT) plays a role in mediating alterations of epithelial permeability in response to CPS. Methods Male rats were subjected to 1-hour water avoidance (WA) stress or subcutaneous CORT injection daily for 10 consecutive days in the presence or absence of corticoid-receptor antagonist RU-486. The visceromotor response (VMR) to colorectal distension (CRD) was measured. The in situ single-pass intestinal perfusion was used to measure intestinal permeability in jejunum and colon simultaneously. Key Results We observed significant decreases in the levels of glucocorticoid receptor (GR) and tight junction proteins in the colon but not the jejunum in stressed rats. These changes were largely reproduced by serial CORT injections in control rats and were significantly reversed by RU-486. Stressed and CORT-injected rats demonstrated a 3-fold increase in permeability for PEG-400 (MW) in colon but not jejunum and significant increase in VMR to CRD, which was significantly reversed by RU-486. In addition, no differences in permeability to PEG-4,000 and PEG-35,000 were detected between control and WA groups. Conclusions & Inferences Our findings indicate that CPS was associated with region-specific decrease in epithelial tight junction protein levels in the colon, increased colon epithelial permeability to low-molecular weight macromolecules which were largely reproduced by CORT treatment in control rats and prevented by RU-486. These observations implicate a novel, region-specific role for CORT as a mediator of CPS-induced increased permeability to macromolecules across the colon epithelium. PMID:23336591

Latest developments at the ALBA magnetic measurements laboratory

NASA Astrophysics Data System (ADS)

Marcos, J.; Massana, V.; García, L.; Campmany, J.

2018-02-01

ALBA is a third-generation synchrotron light source that has been in operation since 2012 near Barcelona. A magnetic measurements laboratory has been associated with the facility since its very early stages and has been active for the last 20 years. In the first part of this work, the different instruments available at the laboratory are described, and a brief overview of the measurement campaigns carried out during its 20 years of history is presented. In the second part, a more detailed description of the approach to Hall probe measurements adopted at ALBA is offered, with an explanation of the methods and ancillary equipment that have been developed along the years in order to improve the accuracy of the system. In the third part, a new concept of Hall probe bench devoted to the measurement of closed structures is presented. The in-house design and building of a prototype for such a bench is described, together with its mechanical and magnetic characterization. As a conclusion, the first results obtained with this bench are discussed.

Filtration and clogging of permeable pavement loaded by urban drainage.

PubMed

Sansalone, J; Kuang, X; Ying, G; Ranieri, V

2012-12-15

Permeable pavement, as a sustainable infrastructure material can promote hydrologic restoration, particulate matter (PM) and solute control. However, filtration and commensurate clogging are two aspects of continued interest and discussion. This study quantifies filtration and clogging of cementitious permeable pavement (CPP) for loadings from 50 to 200 mg/L of hetero-disperse sandy-silt PM. The CPP mix design provides a hetero-disperse pore size distribution (PSD)(pore), effective porosity (φ(e)) of 24% and median pore size of 658 μm with a standard deviation of 457 μm. The PM mass separation across the entire particle size distribution (PSD)(PM) exceeds 80%; with complete separation for PM greater than 300 μm and 50% separation for suspended PM. Turbidity is reduced (42-95%), and effluent is below 10 NTU in the first quartile of a loading period. Permeable pavement illustrates reductions in initial (clean-bed) hydraulic conductivity (k(0)) with loading time. For all PM loadings, k(0) (3.1 × 10(-1) mm/s) was reduced to 10(-4) mm/s for runoff loading durations from 100 to 250 h, respectively. Temporal hydraulic conductivity (k) follows exponential profiles. Maintenance by vacuuming and sonication illustrate that 96-99% of k(0) is recovered. Permeable pavement constitutive properties integrated with measured PM loads and a year of continuous rainfall-runoff simulation illustrate k reduction with historical loadings. Study results measure and model filtration and hydraulic conductivity phenomena as well as maintenance requirements of permeable pavement directly loaded by urban drainage. Copyright © 2011. Published by Elsevier Ltd.

Tunnel Face Stability and the Effectiveness of Advance Drainage Measures in Water-Bearing Ground of Non-uniform Permeability

NASA Astrophysics Data System (ADS)

Zingg, Sara; Anagnostou, Georg

2018-01-01

Non-uniform permeability may result in complex hydraulic head fields with potentially very high hydraulic gradients close to the tunnel face, which may be adverse for stability depending on the ground strength. Pore pressure relief by drainage measures in advance of the tunnel excavation improves stability, but the effectiveness of drainage boreholes may be low in the case of alternating aquifers and aquitards. This paper analyses the effects of hydraulic heterogeneity and advance drainage quantitatively by means of limit equilibrium computations that take account of the seepage forces acting upon the ground in the vicinity the tunnel face. The piezometric field is determined numerically by means of steady-state, three-dimensional seepage flow analyses considering the heterogeneous structure of the ground and a typical advance drainage scheme consisting of six axial boreholes drilled from the tunnel face. A suite of stability analyses was carried out covering a wide range of heterogeneity scales. The computational results show the effect of the orientation, thickness, location, number and permeability ratio of aquifers and aquitards and provide valuable indications about potentially critical situations, the effectiveness of advance drainage and the adequate arrangement of drainage boreholes. The paper shows that hydraulic heterogeneity results in highly variable face behaviour, even if the shear strength of the ground is constant along the alignment, but ground behaviour is considerably less variable in the presence of advance drainage measures.

Useful measures and models for analytical quality management in medical laboratories.

PubMed

Westgard, James O

2016-02-01

The 2014 Milan Conference "Defining analytical performance goals 15 years after the Stockholm Conference" initiated a new discussion of issues concerning goals for precision, trueness or bias, total analytical error (TAE), and measurement uncertainty (MU). Goal-setting models are critical for analytical quality management, along with error models, quality-assessment models, quality-planning models, as well as comprehensive models for quality management systems. There are also critical underlying issues, such as an emphasis on MU to the possible exclusion of TAE and a corresponding preference for separate precision and bias goals instead of a combined total error goal. This opinion recommends careful consideration of the differences in the concepts of accuracy and traceability and the appropriateness of different measures, particularly TAE as a measure of accuracy and MU as a measure of traceability. TAE is essential to manage quality within a medical laboratory and MU and trueness are essential to achieve comparability of results across laboratories. With this perspective, laboratory scientists can better understand the many measures and models needed for analytical quality management and assess their usefulness for practical applications in medical laboratories.

Anisotropy of permeability of reservoir rocks over Miaoli area, NW Taiwan.

NASA Astrophysics Data System (ADS)

Bo-Siang, Xiong; Loung-Yie, Tsai

2013-04-01

The amount of the CO2 has risen since the Industrial Evolution. In order to reduce the amount of CO2 in atmosphere, CO2 sequestration is considered to be the most effective way. In recent years, research about subsurface storage of CO2 into geological formations has increased rapidly. Assessment of storage capability is needed before selecting a site for sequestration. Porosity and permeability are important assessment factors for CO2 sequestration in reservoir rocks. In order to improve the assessment, reservoir rock properties are important and need to be evaluated in advance. Porosity of sandstone is controlled by texture and degree of cementation, whereas permeability is controlled by pore-throat size, pore types and connectivity of pore throat. Sandstones of Miocene to Pleistocene in Miaoli area, NW Taiwan, were collected in this study. YOKO2 porosity/permeability detector is used to measure their permeability perpendicular and parallel to bedding planes under 3 to 60MPa confining pressure with Helium as media. Optical microscope and scanning electron microscope (SEM) were then used to observe the mineral composition, lithology, texture and pore type of sandstones, so as to explore the influence of rock properties on porosity and anisotropy of permeability, as well as the storage potential for CO2 sequestration in the future. The experimental results show that most of the horizontal permeability exceeds the vertical permeability and the anisotropy increases with increasing confining pressure. Mineral composition of sandstones studied were mainly quartz and lithic with little feldspar content. The pore types were mainly primary pores and micropores in this study. The correlation between quantity of macropores and permeability were higher than total porosity and permeability, mainly due to total porosity contains micropores which contribute little to permeability.

Fluorescein isothiocyanate (FITC)-Dextran Extravasation as a Measure of Blood-Brain Barrier Permeability

PubMed Central

Natarajan, Reka; Northrop, Nicole

2017-01-01

The blood-brain barrier (BBB) is formed in part by vascular endothelial cells that constitute the capillaries and microvessels of the brain. The function of this barrier is to maintain homeostasis within the brain microenvironment and buffer the brain from changes in the periphery. A dysfunction of the BBB would permit circulating molecules and pathogens typically restricted to the periphery to enter the brain and interfere with normal brain function. As increased permeability of the BBB is associated with several neuropathologies, it is important to have a reliable and sensitive method that determines BBB permeability and the degree of BBB disruption. A detailed protocol is presented for assessing the integrity of the BBB by transcardial perfusion of a 10,000 Da FITC labeled dextran molecule and its visualization to determine the degree of extravasation from brain microvessels. PMID:28398646

Estimating dynamic permeability in fractal pore network saturated by Maxwellian fluid

NASA Astrophysics Data System (ADS)

Sun, W.

2017-12-01

The frequency dependent flow of fluid in porous media is an important issue in geophysical prospecting. Oscillating flow in pipe leads to frequency dependent dynamic permeability and has been studied in pore network containing Newtonian fluid. But there is little work on oscillating complex fluid in pipe network, especially in irregular network. Here we formulated frequency dependent permeability for Maxwellian fluid and estimated the permeability in three-dimensional fractal network model. We consider an infinitely long cylindrical pipe with rigid solid wall. The pipe is filled with Maxwellian fluids. Based on the mass conservation equation, the equilibrium equation of force and Maxwell constitutive relationship, we formulated the flux by integration of axial velocity component over the pipe's cross section. Then we extend single pipe formulation to a 3D irregular network. Flux balance condition yields a set of linear equations whose unknowns are the fluid pressure at each node. By evaluating the total flow flux through the network, the dynamic permeability can be calculated.We investigated the dynamic permeability of brine and CPyCl/NaSal in a 3D porous sample with a cubic side length 1 cm. The pore network is created by a Voronoi cell filling method. The porosity, i.e., volume ratio between pore/pipe network and the overall cubic, is set as 0.1. The irregular pore network has a fractal structure. The dimension d of the pore network is defined by the relation between node number M within a sphere and the radius r of the sphere,M=rd.The results show that both brine and Maxwellian fluid's permeability maintain a stable value at low frequency, then decreases with fluctuating peaks. The dynamic permeability in pore networks saturated by Maxwellian fluid (CPyCl/NaSal (60 mM)) show larger peaks during the decline process at high frequency, which represents the typical resonance behavior. Dynamic permeability shows clear dependence on the dimension of the fractal

Development of an ion-pair to improve the colon permeability of a low permeability drug: Atenolol.

PubMed

Lozoya-Agullo, Isabel; González-Álvarez, Isabel; González-Álvarez, Marta; Merino-Sanjuán, Matilde; Bermejo, Marival

2016-10-10

To ensure the optimal performance of oral controlled release formulations, drug colon permeability is one of the critical parameters. Consequently developing this kind of formulations for low permeability molecules requires strategies to increase their ability to cross the colonic membrane. The objective of this work is to show if an ion-pair formation can improve the colon permeability of atenolol as a low permeability drug model. Two counter ions have been tested: brilliant blue and bromophenol blue. The Distribution coefficients at pH7.00 (DpH7) of atenolol, atenolol + brilliant blue and atenolol + bromophenol blue were experimentally determined in n-octanol. Moreover, the colonic permeability was determined in rat colon using in situ closed loop perfusion method based in Doluisio's Technique. To check the potential effects of the counter ions on the membrane integrity, a histological assessment of colonic tissue was done. The results of the partitioning studies were inconclusive about ion-pair formation; nevertheless colon permeability was significantly increased by both counter ions (from 0.232±0.021cm/s to 0.508±0.038cm/s in the presence of brilliant blue and to 0.405±0.044cm/s in the presence of bromophenol blue). Neither damage on the membrane was observed on the histological studies, nor any change on paracellular permeability suggesting that the permeability enhancement could be attributed to the ion-pair formation. Copyright © 2016 Elsevier B.V. All rights reserved.

Effective stress law for the permeability and deformation of four porous limestones

NASA Astrophysics Data System (ADS)

Wang, Y.; Meng, F.; Wang, X.; Baud, P.; Wong, T. F.

2017-12-01

The effective stress behavior of a rock is related to the geometric of its pore space. In a microscopically homogeneous assemblage, effective stress coefficients for permeability, volumetric strain and porosity change are predicted to be equal to or less than unity. Experimental measurements are in basic agreement with this prediction, with exceptions particularly in clay-rich sandstones, for which effective stress coefficient for permeability up to 7 was documented. Little is known about carbonates, but Ghabezloo et al. [2009] studied the permeability of an oolitic limestone (from Nimes, France) with 17% porosity and reported effective stress coefficients up to 2.4. We investigated this phenomenon in Indiana, Leitha, Purbeck, and Thala limestones with porosities of 13-30%. Measurements were made at room temperature on water-saturated samples at confining and pore pressures of 7-15 MPa and 1-3 MPa, respectively. Unlike previous studies limited to the permeability, we also determined the effective stress coefficients for volumetric strain and porosity change. Indiana limestone is oolitic, and not surprisingly its behaviour was similar to Nimes limestone, with an effective stress coefficient for permeability of 2.5. Our Indiana limestone data showed that whereas the effective stress coefficient for volumetric strain was <1, that for porosity change was >1. Measurements on Purbeck and Thala limestones are consistent with these inequalities, with effective stress coefficients for permeability and porosity change >1 and that for volumetric strain <1. Even though Purbeck and Thala limestones are micritic with appreciable amount of quartz and dolomite, microstructural and mercury porosimetry data showed that their pore spaces are similar to the oolitic limestones, in that the pore size distribution is bimodal with significant fractions of both macropores and micropores. Berryman [1992] analyzed theoretically a rock made up of two porous constituents. Our new data are in

Effect of surface protection on the permeability of eroded dentin

PubMed Central

Martins, Vivian Leite; da Costa Ramos, Rodrigo Vitoria; Pimenta Lima, Max José; Correia de Araújo, Roberto Paulo; Cavalcanti, Andrea Nóbrega

2018-01-01

Context: Eroded dentin might present the opening of dentinal tubules, increasing permeability, and consequently dentinal hypersensitivity. Aims: This study evaluated the permeability of dentin surfaces exposed to different levels of erosion and methods of surface protection. Materials and Methods: Dentine samples (3 mm × 3 mm × 1 mm) were prepared from bovine incisors (n = 90) and divided into three groups according to the method of controlling erosive challenge: Negative control, topical fluoride application, and glass ionomer sealant. Subsequently, they were randomly divided into three subgroups according to the exposure of simulated gastric acid solution (Demineralization – DES) (5% HCl, pH = 2.2), and remineralization (RE); negative control, 9 and 18 cycles DES-RE. The dentin permeability was measured by assessing the hydraulic conductance (μl/min.cmH2O.cm2). Statistical analysis was performed by two-way ANOVA and Tukey's test. Results and Conclusions: Greater permeability was observed after 18 erosive cycles, followed by exposure to 9 cycles and negative control (P < 0.0001). The application of glass ionomer sealant resulted in a major reduction of the hydraulic conductivity, regardless of the erosive challenge. Control groups and topical fluoride application showed similar results. In conclusion, the severity of erosive challenge contributed to the increase of dentin permeability. Besides, the glass ionomer sealant was the only protection agent that promoted significant effects in dentin permeability. PMID:29628641

Supplanting the rapid chloride permeability test with a quick measurement of concrete conductivity.

DOT National Transportation Integrated Search

2005-01-01

The rapid chloride permeability test (RCPT) (AASHTO T 277, ASTM C 1202) is increasingly being used as an acceptance test for concrete constructions in the transportation industry. As more and more projects are subject to such testing, the capabilitie...

Permeability of lipid bilayers to amino acids and phosphate

NASA Technical Reports Server (NTRS)

Chakrabarti, A. C.; Deamer, D. W.

1992-01-01

Permeability coefficients for amino acid classes, including neutral, polar, hydrophobic, and charged species, were measured and compared with values for other ionic solutes such as phosphate. The rates of efflux of glycine, lysine, phenylalanine, serine and tryptophan were determined after they were passively entrapped in large unilamellar vesicles (LUVs) composed of egg phosphatidylcholine (EPC) or dimyristoylphosphatidylcholine (DMPC). The following permeability coefficients were obtained for: glycine, 5.7 x 10(-12) cm s-1 (EPC), 2.0 x 10(-11) cm s-1 (DMPC); serine, 5.5 x 10(-12) cm s-1 (EPC), 1.6 x 10(-11) cm s-1 (DMPC); lysine, 5.1 x 10(-12) cm s-1 (EPC), 1.9 x 10(-11) cm s-1 (DMPC); tryptophan, 4.1 x 10(-10) cm s-1 (EPC); and phenylalanine, 2.5 x 10(-10) cm s-1 (EPC). Decreasing lipid chain length increased permeability slightly, while variations in pH had only minor effects on the permeability coefficients of the amino acids tested. Phosphate permeability was in the range of 10(-12)-10(-13) cm s-1 depending on the pH of the medium. The values for the polar and charged amino acids were surprisingly similar to those previously measured for monovalent cations such as sodium and potassium, which are in the range of 10(-12)-10(-13) cm s-1, depending on conditions and the lipid species used. This observation suggests that the permeation rates for the neutral, polar and charged amino acids are controlled by bilayer fluctuations and transient defects, rather than partition coefficients and Born energy barriers. The results are relevant to the permeation of certain peptides into lipid bilayers during protein translocation and membrane biogenesis.

The measure of treatment agreement between portable and laboratory blood gas measurements in guiding protocol-driven ventilator management.

PubMed

Thomas, Frank O; Hoffman, Terri L; Handrahan, Diana L; Crapo, Robert O; Snow, Greg

2009-08-01

Portable blood gas analyzer and monitor devices are increasingly being used to direct ventilator therapy. The purpose of this study was to evaluate the "measure of treatment agreement" between portable and laboratory blood gas measurements used in guiding protocol-driven ventilator management. Using National Institutes of Health Acute Respiratory Distress Syndrome network ventilator management guidelines to manage patient care, measurements taken from the Nonin 8500 M pulse oximeter (SpO2), the Novametrix-610 end-tidal CO2 (ETCO2) detector, and the i-STAT 1 (SaO2, PO2, pH, PCO2) were compared with the recommended treatment from paired laboratory ABL-725 (SaCO2, PO2, pH, PCO2) measurements. Four hundred forty-six intubated adult intensive care unit patients were studied prospectively. Except for the ETCO2 (R2 = 0.460), correlation coefficients between portable and laboratory measurements were high (R2 > or = 0.755). Testing for equivalence, the Nonin-SpO2, iSTAT-PO2, iSTAT-pH, and iSTAT-PCO2 were deemed "equivalent" surrogates to paired ABL measurements. Testing for the limits of agreement found only the iSTAT-PCO2 to be an acceptable surrogate measurement. The measure of treatment agreement between the portable and paired laboratory blood gas measurements were Nonin-SpO2 (68%), iSTAT-SaO2 (73%), iSTAT-PO2 (97%), iSTAT-pH (88%), iSTAT-PCO2 (95%), and Novametrix-ETCO2 (60%). Only the iSTAT-PO2 and the iSTAT-PCO2 achieved the > or =95% treatment agreement threshold to be considered as acceptable surrogates to laboratory measurements. : The iSTAT-PO2 and -PCO2 were portable device measurements acceptable as surrogates to standard clinical laboratory blood gas measurements in guiding protocol-directed ventilator management. The "measure of treatment agreement," based on standardized decisions and measurement thresholds of a protocol, provides a simple method for assessing clinical validity of surrogate measurements.

Method and apparatus for in situ determination of permeability and porosity

DOEpatents

Lagus, Peter L.; Peterson, Edward W.

1982-10-12

A method and apparatus for in situ measurement of flow characteristics in boreholes or the like is disclosed for determining various formation characteristics such as permeability, particularly in the range of approximately 100-1,000 microdarcies and lower. One embodiment of the method and apparatus contemplates formation of a test interval in the borehole by a pair of expandable packers, additional guard zones being formed in the borehole at either end of the test interval by two additional guard packers, suitable flow conditions being simultaneously and separately measured within the test interval and each of the guard zones in order to permit determination of multidirectional components of permeability, porosity and other characteristics of the particular formation. Another embodiment contemplates whole hole testing where similar data is developed for a test interval formed between a single packer and the end of the borehole and one guard zone formed by a single additional guard packer. The method and apparatus of this invention are particularly contemplated for obtaining unambiguous measurements of multidirectional flow in low permeability formations.

Correlation of Three Techniques for Determining Soil Permeability

ERIC Educational Resources Information Center

Winneberger, John T.

1974-01-01

Discusses problems of acquiring adequate results when measuring for soil permeability. Correlates three relatively simple techniques that could be helpful to the inexperienced technician dealing with septic tank practices. An appendix includes procedures for valid percolation tests. (MLB)

Effect of temperature on the permeability of gas adsorbed coal under triaxial stress conditions

NASA Astrophysics Data System (ADS)

Li, Xiangchen; Yan, Xiaopeng; Kang, Yili

2018-04-01

The combined effects of gas sorption, stress and temperature play a significant role in the changing behavior of gas permeability in coal seams. The effect of temperature on nitrogen and methane permeability of naturally fractured coal is investigated. Coal permeability, P-wave velocity and axial strain were simultaneously measured under two effective stresses and six different temperatures. The results showed that the behavior of nitrogen and methane permeability presented nonmonotonic changes with increasing temperature. The variation in the P-wave velocity and axial strain showed a good correspondence with coal permeability. A higher effective stress limited the bigger deformation and caused the small change in permeability. Methane adsorption and desorption significantly influence the mechanical properties of coal and play an important role in the variations in coal permeability. The result of coal permeability during a complete stress-strain process showed that the variation in permeability is determined by the evolution of the internal structure. The increase in the temperature of the gas saturated coal causes the complex interaction between matrix swelling, matrix shrinkage and micro-fracture generation, which leads to the complex changes in coal structure and permeability. These results are helpful to understand the gas transport mechanism for exploiting coal methane by heat injection.

Mixed Gas Hydrogen Sulfide Permeability and Separation Using Supported Polyphosphazene Membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frederick F. Stewart; Christopher J. Orme

Three phosphazene polymers were characterized for permeability using a suite of pure gases, including H2S where high permeabilities were measured with respect to the other gases in the study. Furthermore, mixed gas selectivities were determined and compared to the ideal gas selectivities for the H2S/CH4, CO2/CH4, and Ar/CH4 gas pairs. The three phosphazenes represent a set of membrane materials differing by their polarities. Description of the polarity of each was performed using Hansen solubility parameters derived from group contributions for each chemical structure. A good correlation was observed between the polar Hansen parameter (äp) and the gas permeabilities of bothmore » CO2 and H2S. Furthermore, permeant gas critical temperatures were also found to correlate with permeability suggesting a solubility driven transport process. A comparison of the mixed gas permeabilities with the corresponding pure gas data revealed good agreement in the data, although the presence of more condensable gases hinders non-polar gas transport resulting in higher separation factors.« less

Estimation of In Situ Stress and Permeability from an Extended Leak-off Test

NASA Astrophysics Data System (ADS)

Nghiep Quach, Quoc; Jo, Yeonguk; Chang, Chandong; Song, Insun

2016-04-01

stress regime with the information of the maximum principal stress that will be estimated based on borehole breakout geometry analysis. To estimate the in situ permeability from the XLOT data, we derived a theoretical equation that relates the slope of pressure versus injected water volume (P-V) curve to permeability based on the Darcy's law. The equation is expressed in terms of permeability as a function of some key parameters such as open-hole dimensions, flowrate, porosity, pressure change and injected water volume. We applied this equation to the early stage of the P-V curves prior to the leak-off point to prevent the effect of induced fractures on permeability. The estimated in situ permeability was (3.1±0.4)×10-17m2, which turns out to be quite similar to the laboratory measurements in recovered cores.

Benchmarking of relative permeability

NASA Astrophysics Data System (ADS)

DiCarlo, D. A.

2017-12-01

Relative permeability is the key relation in terms of multi-phase flow through porous media. There are hundreds of published relative permeability curves for various media, some classic (Oak 90 and 91), some contradictory. This can lead to a confusing situation if one is trying to benchmark simulation results to "experimental data". Coming from the experimental side, I have found that modelers have too much trust in relative permeability data sets. In this talk, I will discuss reasons for discrepancies within and between data sets, and give guidance on which portions of the data sets are most solid in terms of matching through models.

Modeling relative permeability of water in soil: Application of effective-medium approximation and percolation theory

NASA Astrophysics Data System (ADS)

Ghanbarian, Behzad; Sahimi, Muhammad; Daigle, Hugh

2016-07-01

Accurate prediction of the relative permeability to water under partially saturated condition has broad applications and has been studied intensively since the 1940s by petroleum, chemical, and civil engineers, as well as hydrologists and soil scientists. Many models have been developed for this purpose, ranging from those that represent the pore space as a bundle of capillary tubes, to those that utilize complex networks of interconnected pore bodies and pore throats with various cross-section shapes. In this paper, we propose an approach based on the effective-medium approximation (EMA) and percolation theory in order to predict the water relative permeability. The approach is general and applicable to any type of porous media. We use the method to compute the water relative permeability in porous media whose pore-size distribution follows a power law. The EMA is invoked to predict the relative permeability from the fully saturated pore space to some intermediate water saturation that represents a crossover from the EMA to what we refer to as the "critical region." In the critical region below the crossover water saturation Swx, but still above the critical water saturation Swc (the residual saturation or the percolation threshold of the water phase), the universal power law predicted by percolation theory is used to compute the relative permeability. To evaluate the accuracy of the approach, data for 21 sets of undisturbed laboratory samples were selected from the UNSODA database. For 14 cases, the predicted relative permeabilities are in good agreement with the data. For the remaining seven samples, however, the theory underestimates the relative permeabilities. Some plausible sources of the discrepancy are discussed.

Clogging in permeable concrete: A review.

PubMed

Kia, Alalea; Wong, Hong S; Cheeseman, Christopher R

2017-05-15

Permeable concrete (or "pervious concrete" in North America) is used to reduce local flooding in urban areas and is an important sustainable urban drainage system. However, permeable concrete exhibits reduction in permeability due to clogging by particulates, which severely limits service life. This paper reviews the clogging mechanism and current mitigating strategies in order to inform future research needs. The pore structure of permeable concrete and characteristics of flowing particulates influence clogging, which occurs when particles build-up and block connected porosity. Permeable concrete requires regular maintenance by vacuum sweeping and pressure washing, but the effectiveness and viability of these methods is questionable. The potential for clogging is related to the tortuosity of the connected porosity, with greater tortuosity resulting in increased potential for clogging. Research is required to develop permeable concrete that can be poured on-site, which produces a pore structure with significantly reduced tortuosity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Subsurface imaging of water electrical conductivity, hydraulic permeability and lithology at contaminated sites by induced polarization

NASA Astrophysics Data System (ADS)

Maurya, P. K.; Balbarini, N.; Møller, I.; Rønde, V.; Christiansen, A. V.; Bjerg, P. L.; Auken, E.; Fiandaca, G.

2018-05-01

At contaminated sites, knowledge about geology and hydraulic properties of the subsurface and extent of the contamination is needed for assessing the risk and for designing potential site remediation. In this study, we have developed a new approach for characterizing contaminated sites through time-domain spectral induced polarization. The new approach is based on: (1) spectral inversion of the induced polarization data through a reparametrization of the Cole-Cole model, which disentangles the electrolytic bulk conductivity from the surface conductivity for delineating the contamination plume; (2) estimation of hydraulic permeability directly from the inverted parameters using a laboratory-derived empirical equation without any calibration; (3) the use of the geophysical imaging results for supporting the geological modelling and planning of drilling campaigns. The new approach was tested on a data set from the Grindsted stream (Denmark), where contaminated groundwater from a factory site discharges to the stream. Two overlapping areas were covered with seven parallel 2-D profiles each, one large area of 410 m × 90 m (5 m electrode spacing) and one detailed area of 126 m × 42 m (2 m electrode spacing). The geophysical results were complemented and validated by an extensive set of hydrologic and geologic information, including 94 estimates of hydraulic permeability obtained from slug tests and grain size analyses, 89 measurements of water electrical conductivity in groundwater, and four geological logs. On average the IP-derived and measured permeability values agreed within one order of magnitude, except for those close to boundaries between lithological layers (e.g. between sand and clay), where mismatches occurred due to the lack of vertical resolution in the geophysical imaging. An average formation factor was estimated from the correlation between the imaged bulk conductivity values and the water conductivity values measured in groundwater, in order to

Rapid and reversible enhancement of blood–brain barrier permeability using lysophosphatidic acid

PubMed Central

On, Ngoc H; Savant, Sanjot; Toews, Myron; Miller, Donald W

2013-01-01

The present study characterizes the effects of lysophosphatidic acid (LPA) on blood–brain barrier (BBB) permeability focusing specifically on the time of onset, duration, and magnitude of LPA-induced changes in cerebrovascular permeability in the mouse using both magnetic resonance imaging (MRI) and near infrared fluorescence imaging (NIFR). Furthermore, potential application of LPA for enhanced drug delivery to the brain was also examined by measuring the brain accumulation of radiolabeled methotrexate. Exposure of primary cultured brain microvessel endothelial cells (BMECs) to LPA produced concentration-dependent increases in permeability that were completely abolished by clostridium toxin B. Administration of LPA disrupted BBB integrity and enhanced the permeability of small molecular weight marker gadolinium diethylenetriaminepentaacetate (Gd-DTPA) contrast agent, the large molecular weight permeability marker, IRdye800cwPEG, and the P-glycoprotein efflux transporter probe, Rhodamine 800 (R800). The increase in BBB permeability occurred within 3 minutes after LPA injection and barrier integrity was restored within 20 minutes. A decreased response to LPA on large macromolecule BBB permeability was observed after repeated administration. The administration of LPA also resulted in 20-fold enhancement of radiolabeled methotrexate in the brain. These studies indicate that administration of LPA in combination with therapeutic agents may increase drug delivery to the brain. PMID:24045401

Permeable pavement study (Edison)

EPA Pesticide Factsheets

While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types have on nutrient concentrations present in stormwater runoff are limited. In 2009, the U.S. EPA constructed a 0.4-ha parking lot in Edison, New Jersey, that incorporated permeable interlocking concrete pavement (PICP), pervious concrete (PC), and porous asphalt (PA). Each permeable pavement type has four, 54.9-m2, lined sections that direct all infiltrate into 5.7-m3 tanks enabling complete volume collection and sampling. This paper highlights the results from a 12-month period when samples were collected from 13 rainfall/runoff events and analyzed for nitrogen species, orthophosphate, and organic carbon. Differences in infiltrate concentrations among the three permeable pavement types were assessed and compared with concentrations in rainwater samples and impervious asphalt runoff samples, which were collected as controls. Contrary to expectations based on the literature, the PA infiltrate had significantly larger total nitrogen (TN) concentrations than runoff and infiltrate from the other two permeable pavement types, indicating that nitrogen leached from materials in the PA strata. There was no significant difference in TN concentration between runoff and infiltrate from either PICP or PC, but TN in runoff was significantly larger than in the rainwater, suggesting meaningful inter-event dry de

Permeability and compression characteristics of municipal solid waste samples

NASA Astrophysics Data System (ADS)

Durmusoglu, Ertan; Sanchez, Itza M.; Corapcioglu, M. Yavuz

2006-08-01

Four series of laboratory tests were conducted to evaluate the permeability and compression characteristics of municipal solid waste (MSW) samples. While the two series of tests were conducted using a conventional small-scale consolidometer, the two others were conducted in a large-scale consolidometer specially constructed for this study. In each consolidometer, the MSW samples were tested at two different moisture contents, i.e., original moisture content and field capacity. A scale effect between the two consolidometers with different sizes was investigated. The tests were carried out on samples reconsolidated to pressures of 123, 246, and 369 kPa. Time settlement data gathered from each load increment were employed to plot strain versus log-time graphs. The data acquired from the compression tests were used to back calculate primary and secondary compression indices. The consolidometers were later adapted for permeability experiments. The values of indices and the coefficient of compressibility for the MSW samples tested were within a relatively narrow range despite the size of the consolidometer and the different moisture contents of the specimens tested. The values of the coefficient of permeability were within a band of two orders of magnitude (10-6-10-4 m/s). The data presented in this paper agreed very well with the data reported by previous researchers. It was concluded that the scale effect in the compression behavior was significant. However, there was usually no linear relationship between the results obtained in the tests.

Permeability Evolution of Fractured Anhydrite Caused by Chemical and Mechanical Alteration

NASA Astrophysics Data System (ADS)

Detwiler, R. L.; Elkhoury, J. E.; Ameli, P.

2011-12-01

Geologic carbon sequestration requires competent structural seals (caprock) to prevent leakage over decadal time scales. Injection of large volumes of CO2 perturbs the target formation from chemical and mechanical equilibrium leading to the possible creation or enhancement of leakage pathways. We investigate the potential for leakage pathways (fractures) to grow over time under reservoir conditions in a series of anhydrite (Ca2SO4) cores. To simulate a potential leakage event in the laboratory, we fractured and jacketed the cores, and placed them in a flow-through reactor vessel. A high-pressure syringe pump applied confining stresses ranging from 7 to 17 MPa and another syringe pump pushed water through the sample at a constant flow rate with pressure control at the outlet. Effluent was sampled periodically and analyzed for Ca2+ and SO42- using an ion chromatograph. Before and after each experiment, we characterized the surfaces of the fractures using a high-resolution optical profilometer and a scanning electron microscope. Careful alignment of the surfaces during optical profiling allowed reproduction of the fracture aperture before and after each experiment. We present results from several experiments each carried out under different conditions in similar fractured anhydrite cores. One involved a well-mated pre-existing fracture and results showed that the permeability of the fractured core was similar to the intact rock matrix (O(10-18 m2); chemical alteration of the core was largely limited to the inflow face of the core and the fracture surfaces remained largely unaltered. To enhance permeability during subsequent experiments, we imposed a small (380 μm) shear displacement between the fracture surfaces resulting in a four-order-of-magnitude increase in initial permeability. The first of these was run at a constant flow rate of 0.6 ml/min for a period of 7 days. The measured pressure gradient within the core increased slowly for a period of 4 days followed

Identification of small-scale low and high permeability layers using single well forced-gradient tracer tests: fluorescent dye imaging and modelling at the laboratory-scale.

PubMed

Barns, Gareth L; Thornton, Steven F; Wilson, Ryan D

2015-01-01

Heterogeneity in aquifer permeability, which creates paths of varying mass flux and spatially complex contaminant plumes, can complicate the interpretation of contaminant fate and transport in groundwater. Identifying the location of high mass flux paths is critical for the reliable estimation of solute transport parameters and design of groundwater remediation schemes. Dipole flow tracer tests (DFTTs) and push-pull tests (PPTs) are single well forced-gradient tests which have been used at field-scale to estimate aquifer hydraulic and transport properties. In this study, the potential for PPTs and DFTTs to resolve the location of layered high- and low-permeability layers in granular porous media was investigated with a pseudo 2-D bench-scale aquifer model. Finite element fate and transport modelling was also undertaken to identify appropriate set-ups for in situ tests to determine the type, magnitude, location and extent of such layered permeability contrasts at the field-scale. The characteristics of flow patterns created during experiments were evaluated using fluorescent dye imaging and compared with the breakthrough behaviour of an inorganic conservative tracer. The experimental results show that tracer breakthrough during PPTs is not sensitive to minor permeability contrasts for conditions where there is no hydraulic gradient. In contrast, DFTTs are sensitive to the type and location of permeability contrasts in the host media and could potentially be used to establish the presence and location of high or low mass flux paths. Numerical modelling shows that the tracer peak breakthrough time and concentration in a DFTT is sensitive to the magnitude of the permeability contrast (defined as the permeability of the layer over the permeability of the bulk media) between values of 0.01-20. DFTTs are shown to be more sensitive to deducing variations in the contrast, location and size of aquifer layered permeability contrasts when a shorter central packer is used

Thermal infrared remote sensing and Kirchhoff's law: 1. Laboratory measurements

NASA Technical Reports Server (NTRS)

Salisbury, J. W.; Wald, A.; Daria, D. M.

1993-01-01

Kirchoff's Law, as originally conceived, applies only to samples in thermal equilibrium with their surroundings. Most laboratory measurements of emissivity only approach this condition and it never applies in remote sensing applications. In particular, the background is often much cooler than the radiating sample, and this has led to a long controversy about the applicability of Kirchhoff's Law under such conditions. It has also led to field and laboratory measurement techniques that use some form of the 'emissivity box' approach, which surrounds the sample with a background as close as possible to the sample temperature. In our experiments, we have heated soil samples in air on a hot plate in the laboratory to a much higher temperature than the room temperature background. Spectral emissivity was measured, except the known emissivities of both the primary and secondary Christiansen features were used, instead of assuming an emissivity of unity at these wavelengths. The results from this investigation are discussed in brief.

Associations among gut permeability, inflammatory markers, and symptoms in patients with irritable bowel syndrome

USDA-ARS?s Scientific Manuscript database

Alterations in gastrointestinal (GI) permeability and immune measures are present in some patients with irritable bowel syndrome (IBS) but the relationship to symptoms is poorly defined. In adults with IBS, we compared permeability, unstimulated peripheral blood monocyte (PBMC) interleukin-10 (IL-10...

Mineral displacement and -dissolution processes and their relevance to rock porosity and permeability in Rotliegend sandstones of the Altmark natural gas field (central Germany) - results from CO2 laboratory batch experiments

NASA Astrophysics Data System (ADS)

Pudlo, Dieter; Enzmann, Frieder; Heister, Katja; Werner, Lars; Ganzer, Leonhard; Reitenbach, Viktor; Henkel, Steven; Albrecht, Daniel; Gaupp, Reinhard

2014-05-01

The Rotliegend reservoir sandstones of the Altmark area (central Germany) comprise the second largest natural gas field of Europe. These sandstones were deposited on a playa-like continental platform with braided river systems, ephemeral lakes and aeolian dunes under semi-arid conditions. Some of the pristine, red coloured deposits suffered intensive late diagenetic alteration and are now preserved as bleached, high porous and permeable sandstones. To evaluate the relevance of distinct fluids and their fluid-rock alteration reactions on such bleaching processes we performed laboratory static batch experiments on the Altmark sandstones. These 4-6 week lasting runs were conducted with CO2 saturated synthetic brines under typical Altmark reservoir conditions (p= 20 MPa, T= 125°C). Thereby mineralogical, petrophysical and (hydro- and geo-) chemical rock features were maintained prior and after the experiments. Chemical data proved the dissolution of carbonate and sulphate minerals during the runs, whereas the variation in abundance of further elements was within the detection limit of analytical accuracy. However, FE-SEM investigations on used, evaporated brines reveal the presence of illite and chlorite minerals within a matrix of Ca-, Si-, Fe, Al-, Na- and S components (carbonate, anhydrite, albite and Fe-(hydr-) oxides ?). By porosity and relative permeability measurements an increase in both rock features was observed after the runs, indicating that mineral dissolution and/or (clay) fine migration/detachment occurred during the experiments. Mineral dissolution, especially of pore-filling cements (e.g. carbonate-, sulphate minerals) is also deduced by BET analysis, in determining the specific surface of the sandstones. The size of these reactive surfaces increased after the experiments, suggesting that after the dissolution of pore-filling cements, formerly armoured grain rimming clay cutans were exposed to potential migrating fluids. These findings are also

Relative permeability of hydrate-bearing sediments from percolation theory and critical path analysis: theoretical and experimental results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daigle, Hugh; Rice, Mary Anna; Daigle, Hugh

Relative permeabilities to water and gas are important parameters for accurate modeling of the formation of methane hydrate deposits and production of methane from hydrate reservoirs. Experimental measurements of gas and water permeability in the presence of hydrate are difficult to obtain. The few datasets that do exist suggest that relative permeability obeys a power law relationship with water or gas saturation with exponents ranging from around 2 to greater than 10. Critical path analysis and percolation theory provide a framework for interpreting the saturation-dependence of relative permeability based on percolation thresholds and the breadth of pore size distributions, whichmore » may be determined easily from 3-D images or gas adsorption-desorption hysteresis. We show that the exponent of the permeability-saturation relationship for relative permeability to water is related to the breadth of the pore size distribution, with broader pore size distributions corresponding to larger exponents. Relative permeability to water in well-sorted sediments with narrow pore size distributions, such as Berea sandstone or Toyoura sand, follows percolation scaling with an exponent of 2. On the other hand, pore-size distributions determined from argon adsorption measurements we performed on clays from the Nankai Trough suggest that relative permeability to water in fine-grained intervals may be characterized by exponents as large as 10 as determined from critical path analysis. We also show that relative permeability to the gas phase follows percolation scaling with a quadratic dependence on gas saturation, but the threshold gas saturation for percolation changes with hydrate saturation, which is an important consideration in systems in which both hydrate and gas are present, such as during production from a hydrate reservoir. Our work shows how measurements of pore size distributions from 3-D imaging or gas adsorption may be used to determine relative permeabilities.« less

Durable Suit Bladder with Improved Water Permeability for Pressure and Environment Suits

NASA Technical Reports Server (NTRS)

Bue, Grant C.; Kuznetz, Larry; Orndoff, Evelyne; Tang, Henry; Aitchison, Lindsay; Ross, Amy

2009-01-01

Water vapor permeability is shown to be useful in rejecting heat and managing moisture accumulation in launch-and-entry pressure suits. Currently this is accomplished through a porous Gortex layer in the Advanced Crew and Escape Suit (ACES) and in the baseline design of the Constellation Suit System Element (CSSE) Suit 1. Non-porous dense monolithic membranes (DMM) that are available offer potential improvements for water vapor permeability with reduced gas leak. Accordingly, three different pressure bladder materials were investigated for water vapor permeability and oxygen leak: ElasthaneTM 80A (thermoplastic polyether urethane) provided from stock polymer material and two custom thermoplastic polyether urethanes. Water vapor, carbon dioxide and oxygen permeability of the DMM's was measured in a 0.13 mm thick stand-alone layer, a 0.08 mm and 0.05 mm thick layer each bonded to two different nylon and polyester woven reinforcing materials. Additional water vapor permeability and mechanical compression measurements were made with the reinforced 0.05 mm thick layers, further bonded with a polyester wicking and overlaid with moistened polyester fleece thermal underwear .This simulated the pressure from a supine crew person. The 0.05 mm thick nylon reinforced sample with polyester wicking layer was further mechanically tested for wear and abrasion. Concepts for incorporating these materials in launch/entry and Extravehicular Activity pressure suits are presented.