permeability

摘要： Defects in the endothelial cell barrier accompany diverse malfunctions of the central nervous system such as neurodegenerative diseases,stroke,traumatic brain injury,and systemic diseases such as sepsis,viral and bacterial infections,and cancer.Compromised endothelial sealing leads to leaking blood vessels,followed by vasogenic edema.Brain edema as the most common complication caused by stroke and traumatic brain injury is the leading cause of death.Brain microvascular endothelial cells,together with astrocytes,pericytes,microglia,and neurons form a selective barrier,the so-called blood-brain barrier,which regulates the movement of molecules inside and outside of the brain.Mechanisms that regulate blood-brain barrier permeability in health and disease are complex and not fully understood.Several newly discovered molecules that are involved in the regulation of cellular processes in brain microvascular endothelial cells have been described in the literature in recent years.One of these molecules that are highly expressed in brain microvascular endothelial cells is protocadherin gamma C3.In this review,we discuss recent evidence that protocadherin gamma C3 is a newly identified key player involved in the regulation of vascular barrier function.

摘要： During oil and gas fields development,a decrease in reservoir and bottomhole pressure has often a detrimental effect on reservoir properties,especially permeability.This study presents the results of laboratory tests conducted to determine the response of terrigenous reservoir core-sample permeability to changes in the effective stresses and a decrease in the reservoir pressure.The considered samples were exposed for a long time to a constant high effective stress for a more reliable assessment of the viscoplastic deformations.According to these experiments,the decrease of the core samples permeability may reach 21%with a decrease in pressure by 9.5 MPa from the initial reservoir conditions.Numerical simulations have been also conducted.These have been based on the finite element modeling of the near-wellbore zone of the terrigenous reservoir using poroelasticity relations.The simulation results show a limited decrease in reservoir permeability in the near-wellbore zone(by 17%,which can lead to a decrease in the well productivity by 13%).

摘要： Survey and novel research data are used in the present study to classify/identify the lithological type of Verey age reservoirs’rocks.It is shown how the use of X-ray tomography can clarify the degree of heterogeneity,porosity and permeability of these rocks.These data are then used to elaborate a model of hydraulic fracturing.The resulting software can take into account the properties of proppant and breakdown fluid,thermal reservoir conditions,oil properties,well design data and even the filtration and elastic-mechanical properties of the rocks.Calculations of hydraulic fracturing crack formation are carried out and the results are compared with the data on hydraulic fracturing crack at standard conditions.Significant differences in crack formation in standard and lithotype models are determined.It is shown that the average width of the crack development for the lithotype model is 2.3 times higher than that for the standard model.Moreover,the coverage of crack development in height for the lithotype model is almost 2 times less than that for the standard model.The estimated fracture half-length for the lithotype model is 13.3%less than that of for the standard model.A higher dimensionless fracture conductivity is also obtained for the lithotype model.It is concluded that the proposed approach can increase the reliability of hydraulic fracturing crack models.

摘要： Due to seasonal climate alterations,the microstructure and permeability of granite residual soil are easily affected by multiple dry-wet cycles.The X-ray micro computed tomography(micro-CT)acted as a nondestructive tool for characterizing the microstructure of soil samples exposed to a range of damage levels induced by dry-wet cycles.Subsequently,the variations of pore distribution and permeability due to drywet cycling effects were revealed based on three-dimensional(3D)pore distribution analysis and seepage simulations.According to the results,granite residual soils could be separated into four different components,namely,pores,clay,quartz,and hematite,from micro-CT images.The reconstructed 3D pore models dynamically demonstrated the expanding and connecting patterns of pore structures during drywet cycles.The values of porosity and connectivity are positively correlated with the number of dry-wet cycles,which were expressed by exponential and linear functions,respectively.The pore volume probability distribution curves of granite residual soil coincide with the χ^(2)distribution curve,which verifies the effectiveness of the assumption of χ^(2)distribution probability.The pore volume distribution curves suggest that the pores in soils were divided into four types based on their volumes,i.e.micropores,mesopores,macropores,and cracks.From a quantitative and visual perspective,considerable small pores are gradually transformed into cracks with a large volume and a high connectivity.Under the action of dry-wet cycles,the number of seepage flow streamlines which contribute to water permeation in seepage simulation increases distinctly,as well as the permeability and hydraulic conductivity.The calculated hydraulic conductivity is comparable with measured ones with an acceptable error margin in general,verifying the accuracy of seepage simulations based on micro-CT results.

摘要： Based on the rock typing method of pore geometry and structure(PGS), rock samples from carbonate reservoir A and carbonate reservoir B were classified using data of routine and special core analysis and thin section images, and microfractures in the carbonate reservoir samples were identified and characterized. Establishment of rock types demonstrates that microfractures have developed in all rock types in carbonate reservoir A, but only partially in certain rock types in carbonate reservoir B with porosity of 1%–11%, less vuggy, and hardness of medium hard to hard. The cut-off porosity was determined for each type of rock to distinguish samples with and without conductive microfractures. The impact of conductive microfractures on improving permeability was analyzed. On the basis of relationship of permeability and original initial water saturation, the permeability equation was derived by certain special core analysis data with conductive microfractures selected by PGS equation, and the permeability of samples with conductive microfractures has been successfully predicted.

摘要： Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene to plio-quaternary volcanic rocks with variable mineralogy and geochemistry dominate the geology of this region. The presence of active faults in different directions explains the high tectonic instability and the high frequency of earthquakes. This study contributes to the effort of understanding the geothermal potential of the Northeast of Morocco. Heat source and permeability are both key factors in the geothermal process. Indeed, lineaments analysis constrains the structures and their directions and indicates severely faulted zones, which are the most promising areas for geothermal exploration. For this purpose, we used Landsat data combined with geological and structural maps available in this region. Different image processing techniques were applied including band ratio (6/2) and directional filters. To validate the results, we conducted a comparative study between linear structures, available geological data, and previous studies. Results of the automatic extraction method of lineaments from Landsat 8 OLI/TIRS indicate three main lineament systems: 1) a NE-SW system ranging from N40 to N70;2) an N-S system ranging from N10 to N45;3) an EW to WNW-ESE systems ranging from N80 to N120. Most of lineaments extracted are localized in Kebdana, Amejjaou, Nador and Melilla regions. Compared to previous studies, the NE-SW system is consistent with an extensive period (Tortonian to Pliocene);the NW-SE system is consistent with the last compressive episode (Pliocene);the N-S system is consistent with the first compressive period (Late/End Tortonian).

摘要： This review compares the different types of membrane processes for air dehumidification.Three main categories of membrane-based dehumidification are identified–membrane contactors using porous membranes with concentrated liquid desiccants,separative membranes using dense membrane morphology with a pressure gradient to drive the separation of moisture from air,and adsorptive membranes using nanofibrous membranes which adsorb and capture moisture to realise dehumidification.Drawing upon the importance of dehumidification and humidity control for urban sustainability and energy efficacy,this review critically analyses and recognizes the three unique categories of membrane-based air dehumidification technologies.Essentially,the discussion is broken into three sections-one for each category-discriminating in terms of the driving force,membrane structure and properties,and its performance indicators.Readers will notice that despite having the same objective to dehumidify air,the polymers used amongst each category differs to suit the operating requirements and optimize dehumidification performance.At the end of each section,a performance table or summary of dehumidifying membranes in its class is provided.The final section concludes with a comparative review of the three categories on membrane-based air dehumidification technologies and draw inspiration from parallel research to rationalise the potential and innovative use of promising materials in membrane fabrication for air dehumidification.

摘要： Pore network structure of ore body is a diffusion channel of leaching agent solution that exerts a significant influence on seepage.The ore body structure,pore distribution,pore and throat size,and pore network characteristics of topsoil,weathered,and semiweathered layers of ionic rare earth ore in southern Jiangxi Province were explored in this study.The effect of leaching operation on the pore structure was investigated,and main factors affecting the seepage were analyzed.Results showed that the semiweathered layer presents a dense structure and a small number of unconnected pores.Pores of topsoil and weathered layers are mainly long and narrow column openings with some planar fractures.Even pore distribution and large size span were observed.Compared with the weathered layer,the topsoil layer demonstrates larger voids,smaller average pore volume and equivalent radius,and fewer coordination throats;however,the average equivalent radius of the throat in the topsoil layer is larger and largescale channels exist through ore body vertically.Hence,permeability of the topsoil layer is significantly higher than that of the weathered layer.Colloidal clay minerals migrate easily and the occurrence of silting in the small porosity blocks the throat and significantly decreases the permeability of the ore body in the leaching process.The equivalent radius of the throat is the key to the seepage.Reducing the migration of fine particles is an effective measure to protect the throat and shorten the leaching period.

摘要： This study aims at evaluating the influence of the presence of shale on the quality of reservoir sand in “CAC-Field”, Coastal swamp Niger Delta by integrating suites of well logs and 3D pre-stack seismic data. Shales in the reservoir pose interpretation challenges as they form baffles to fluid flow and reduce effective porosity. The data used included well logs (density, gamma ray, neutron, resistivity) and 3D seismic data. Petrel and Interactive Petrophysics software were adopted for the analyses. The Vclay/effective porosity cross-plots were used to determine the clay distribution patterns hence the influence of shale on the petrophysical properties of the hydrocarbon reservoir. Result of the well correlation yielded 12 reservoirs with 4 (RES 4 - RES 7) being hydrocarbon bearing and laterally continuous across the 4 wells, (CAC-1 - CAC-4) forming the focus of the study. Evidence of an NW-SE trending delta progradation in the CAC field is represented by the increasing sandiness downdip, at both intermediate and the shallow horizons. Thickening of the reservoir in some instances may be structurally controlled due to faulting. The results from the petrophysical evaluation show Vclay ranges of 13% - 21% and good to very good porosity values that vary from 15% - 25%. The permeability range from 240.49 - 2406.49 mD except for the sands in RES 7, CAC-3 well where the permeability was low (91 mD). Additionally, the Vclay/Effective Porosity cross-plots indicate essentially laminated and structural clay types with few dispersed clay in RES 7, CAC-3 well. The existence of these 3 clay types did not significantly influence the quality of the sands containing the hydrocarbon in the area, except in RES 7, CAC-3. The compartmentalizing effect of the laminated clay/shale could only possibly affect the vertical flow due to possible baffles to the vertical flow, but the horizontal flow may not have been impeded significantly. The study of the type and pattern of clay has helped to better evaluate the quality and mobility trend of the hydrocarbon in the CAC field.

摘要： The novel polycrystalline Bi0.85Gd0.15CuxFe1-xO3 (x = 0, 0.025, 0.05, 0.075, 0.10) multiferroics are synthesized by the usual solid-state reaction route. The synthesis of the desired phase has been verified by the X-ray Diffraction (XRD) patterns. With major structural phases, few traces of secondary phases of Bi2Fe4O9 and Bi25FeO40 appear for all the compositions. A discontinuous series of structural changes with varying compositions are observed for the doped samples. The bulk density (ρB) increases with Cu content reaches the highest at x = 0.05 and then declines. The complex initial permeability and dielectric characterizations are performed by Wayne Kerr Impedance Analyzer. The x = 0.05 samples having maximum density exhibit the highest permeability (μi’) implying a close relation between μi’ and the density. The reduction of μi’ at higher Cu concentration is due to the low density of the samples associated with the increased intragranular pores. The dielectric constant (ε’) is measured against frequency in the range 1 kHz - 10 MHz. It is perceived that ε’ falls with the rise in frequency up to 100 kHz. This dielectric dispersion is observed at a lower frequency as a result of interfacial polarization outlined by Maxwell-Wagner. The maximum ε’ is obtained for x = 0.025 composition. In the low-frequency range, the AC conductivity σAC is practically independent of frequency and resembles the DC conductivity (σDC). In the vicinity of high frequency recognized as the hopping region, σAC rises since the conductive grains are more active at high frequencies. The co-doping with Gd and Cu in BiFeO3 ceramics enhances the magnetic and dielectric properties of the ceramics and hence can be utilized for fabricating multifunctional devices.

摘要： Reliable mine gas prediction is not only essential for effective gas drainage and control，improvement of mining safety and reduction of coal production costs，but also important to mine gas production assessment for gas utilisation evaluation and planning．An integrated mine gas simulation system has been developed to predict strata conditions and methane gas emission during longwall mining．The system is used to assist selection and planning of suitable mining，gas management and utilisation strategies for new and existing mines．Several key mine gas assessment processes，such as mine site gas and geotechnical characterisation,and fully coupled mechanical deformation-fluid flow computer simulation，have been integrated in the simulation system．Gas flow during mining is controlled by in situ gas content and geotechnical conditions，as well as the mining induced changes in the strata such as those of stress，fracture，pore pressure and permeability.The central part of the integrated simulation system is the new 3D code called COSFLOW that simulates the complex behaviour of rock，water and gas flow，and predicts gas emission during longwall development and retreat．The code is also capable of simulating gas drainage performance and estimating gas production．This system was developed from a recently completed collaborative project entitled “Predevelopment Studies for Mine Methane Management and Utilisation”，between the New Energy and Industrial Technology Development Organization (NEDO) of Japan，the Japan Coal Energy Center (JCOAL)，and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) of Australia．The integrated simulation approach is described in this paper and examples of mine site application are presented．

摘要： Gas emissions and problems in the Australian coal mines have lncreased significantly in recent years as mines reach greater depths and increase longwall production levels and panel sizes.Traditionally，the main objective of gas drainage operations was to meet the safety requirements of the underground coal mines with respect to outburst and frictional ignition.However，with the recent focus on reducing greenhouse gas(GHG) emissions from the mining industry，gas drainage and improved gas capture has become one of the critical GHG mitigation strategies．It was identified that the wider application of gas drainage as a mitigation strategy depends on achieving drainage costs that are less than the combined value of the associated safety，greenhouse and gas revenue benefits．The technique of surface-to-inseam drainage (SIS) also known as Medium Radius Drilling (MRD) technology is gaining acceptance in the coal mining industry as an acceptable means of pre draining virgin underground areas prior to mining operations，although the design and application of the MRD technology is still being developed based on our ever increasing knowledge of coal seam gas behaviour．MRD techniques offer the most promising alternative to Conventional Inseam drilling or‘CIS’drilling．Numerous improvements in drilling techniques have allowed MRD drilling to become more productive and cost effective not the least of which is the management of bottom hole pressures during drilling operations．The control of pressure has improved drilling rates and minimised near surface damage to coal seams which is known to effect drainage performance．Studies by CSIRO have identified the major parameters effecting MRD performance as a result of a two year ACARP funded study into MRD techniques．These parameters are outlined in the following paper．

摘要： Gas emissions and problems in the Australian coal mines have lncreased significantly in recent years as mines reach greater depths and increase longwall production levels and panel sizes.Traditionally，the main objective of gas drainage operations was to meet the safety requirements of the underground coal mines with respect to outburst and frictional ignition.However，with the recent focus on reducing greenhouse gas(GHG) emissions from the mining industry，gas drainage and improved gas capture has become one of the critical GHG mitigation strategies．It was identified that the wider application of gas drainage as a mitigation strategy depends on achieving drainage costs that are less than the combined value of the associated safety，greenhouse and gas revenue benefits．The technique of surface-to-inseam drainage (SIS) also known as Medium Radius Drilling (MRD) technology is gaining acceptance in the coal mining industry as an acceptable means of pre draining virgin underground areas prior to mining operations，although the design and application of the MRD technology is still being developed based on our ever increasing knowledge of coal seam gas behaviour．MRD techniques offer the most promising alternative to Conventional Inseam drilling or‘CIS’drilling．Numerous improvements in drilling techniques have allowed MRD drilling to become more productive and cost effective not the least of which is the management of bottom hole pressures during drilling operations．The control of pressure has improved drilling rates and minimised near surface damage to coal seams which is known to effect drainage performance．Studies by CSIRO have identified the major parameters effecting MRD performance as a result of a two year ACARP funded study into MRD techniques．These parameters are outlined in the following paper．

摘要： Gas emissions and problems in the Australian coal mines have lncreased significantly in recent years as mines reach greater depths and increase longwall production levels and panel sizes.Traditionally，the main objective of gas drainage operations was to meet the safety requirements of the underground coal mines with respect to outburst and frictional ignition.However，with the recent focus on reducing greenhouse gas(GHG) emissions from the mining industry，gas drainage and improved gas capture has become one of the critical GHG mitigation strategies．It was identified that the wider application of gas drainage as a mitigation strategy depends on achieving drainage costs that are less than the combined value of the associated safety，greenhouse and gas revenue benefits．The technique of surface-to-inseam drainage (SIS) also known as Medium Radius Drilling (MRD) technology is gaining acceptance in the coal mining industry as an acceptable means of pre draining virgin underground areas prior to mining operations，although the design and application of the MRD technology is still being developed based on our ever increasing knowledge of coal seam gas behaviour．MRD techniques offer the most promising alternative to Conventional Inseam drilling or‘CIS’drilling．Numerous improvements in drilling techniques have allowed MRD drilling to become more productive and cost effective not the least of which is the management of bottom hole pressures during drilling operations．The control of pressure has improved drilling rates and minimised near surface damage to coal seams which is known to effect drainage performance．Studies by CSIRO have identified the major parameters effecting MRD performance as a result of a two year ACARP funded study into MRD techniques．These parameters are outlined in the following paper．

摘要： Gas emissions and problems in the Australian coal mines have lncreased significantly in recent years as mines reach greater depths and increase longwall production levels and panel sizes.Traditionally，the main objective of gas drainage operations was to meet the safety requirements of the underground coal mines with respect to outburst and frictional ignition.However，with the recent focus on reducing greenhouse gas(GHG) emissions from the mining industry，gas drainage and improved gas capture has become one of the critical GHG mitigation strategies．It was identified that the wider application of gas drainage as a mitigation strategy depends on achieving drainage costs that are less than the combined value of the associated safety，greenhouse and gas revenue benefits．The technique of surface-to-inseam drainage (SIS) also known as Medium Radius Drilling (MRD) technology is gaining acceptance in the coal mining industry as an acceptable means of pre draining virgin underground areas prior to mining operations，although the design and application of the MRD technology is still being developed based on our ever increasing knowledge of coal seam gas behaviour．MRD techniques offer the most promising alternative to Conventional Inseam drilling or‘CIS’drilling．Numerous improvements in drilling techniques have allowed MRD drilling to become more productive and cost effective not the least of which is the management of bottom hole pressures during drilling operations．The control of pressure has improved drilling rates and minimised near surface damage to coal seams which is known to effect drainage performance．Studies by CSIRO have identified the major parameters effecting MRD performance as a result of a two year ACARP funded study into MRD techniques．These parameters are outlined in the following paper．

摘要： Gas emissions and problems in the Australian coal mines have lncreased significantly in recent years as mines reach greater depths and increase longwall production levels and panel sizes.Traditionally，the main objective of gas drainage operations was to meet the safety requirements of the underground coal mines with respect to outburst and frictional ignition.However，with the recent focus on reducing greenhouse gas(GHG) emissions from the mining industry，gas drainage and improved gas capture has become one of the critical GHG mitigation strategies．It was identified that the wider application of gas drainage as a mitigation strategy depends on achieving drainage costs that are less than the combined value of the associated safety，greenhouse and gas revenue benefits．The technique of surface-to-inseam drainage (SIS) also known as Medium Radius Drilling (MRD) technology is gaining acceptance in the coal mining industry as an acceptable means of pre draining virgin underground areas prior to mining operations，although the design and application of the MRD technology is still being developed based on our ever increasing knowledge of coal seam gas behaviour．MRD techniques offer the most promising alternative to Conventional Inseam drilling or‘CIS’drilling．Numerous improvements in drilling techniques have allowed MRD drilling to become more productive and cost effective not the least of which is the management of bottom hole pressures during drilling operations．The control of pressure has improved drilling rates and minimised near surface damage to coal seams which is known to effect drainage performance．Studies by CSIRO have identified the major parameters effecting MRD performance as a result of a two year ACARP funded study into MRD techniques．These parameters are outlined in the following paper．

摘要： Gas emissions and problems in the Australian coal mines have lncreased significantly in recent years as mines reach greater depths and increase longwall production levels and panel sizes.Traditionally，the main objective of gas drainage operations was to meet the safety requirements of the underground coal mines with respect to outburst and frictional ignition.However，with the recent focus on reducing greenhouse gas(GHG) emissions from the mining industry，gas drainage and improved gas capture has become one of the critical GHG mitigation strategies．It was identified that the wider application of gas drainage as a mitigation strategy depends on achieving drainage costs that are less than the combined value of the associated safety，greenhouse and gas revenue benefits．The technique of surface-to-inseam drainage (SIS) also known as Medium Radius Drilling (MRD) technology is gaining acceptance in the coal mining industry as an acceptable means of pre draining virgin underground areas prior to mining operations，although the design and application of the MRD technology is still being developed based on our ever increasing knowledge of coal seam gas behaviour．MRD techniques offer the most promising alternative to Conventional Inseam drilling or‘CIS’drilling．Numerous improvements in drilling techniques have allowed MRD drilling to become more productive and cost effective not the least of which is the management of bottom hole pressures during drilling operations．The control of pressure has improved drilling rates and minimised near surface damage to coal seams which is known to effect drainage performance．Studies by CSIRO have identified the major parameters effecting MRD performance as a result of a two year ACARP funded study into MRD techniques．These parameters are outlined in the following paper．