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Hydraulic rubber dam : an effective water management technology
\"Hydraulic Rubber Dam: An Effective Water Management Technology is the go-to source for information on the materials, manufacture, mechanics and functional benefit of rubber dams in water management. Readers will find a detailed background on water conservation and coverage, how inflatable rubber dam technology contributes to the picture, and information on the proper manufacture and use of rubber dams to increase water storage for release and delivery during drought. In addition, the book presents tactics on the even distribution of water across populations, how to increase water use efficiency, conservation, and how to prevent flooding. In particular, this book details specialist manufacturing techniques, including the development of rubber compounds and fabric, the bonding and anchoring systems which hold the rubber dam to the underlying concrete structure, and inflation and deflation mechanisms for rubber dams. The book provides a holistic lifecycle assessment of rubber dams to give additional insight to readers looking to deploy rubber dam technology\"--Page 4 of cover.
Book
COsub.2 Flow Characteristics in Macro-Scale Coal Sample: Effect of COsub.2 Injection Pressure and Buried Depth
Experimental studies have confirmed the permeability reduction of coal samples upon the adsorption of CO[sub.2]. However, these studies were carried out under limited experimental conditions. In this study, CO[sub.2] flow behaviors in a macro-scale coal sample were numerically simulated using a coupled gas flow, mechanical deformation, and sorption-induced deformation finite element model. The simulation results show that the effect of the reduction of effective stress on the enhancement of permeability is greater than the negative effect of permeability reduction due to CO[sub.2] adsorption for low injection pressures. CO[sub.2] pressure development in the sample increases with increasing injection pressure due to the enhanced advection flux for sub-critical CO[sub.2] injections, while for super-critical CO[sub.2] injections, CO[sub.2] pressure development, as well as concentrations in the sample, decreases compared to sub-critical CO[sub.2] injections because of greater density and viscosity of super-critical CO[sub.2] as well as coal matrix swelling induced by the adsorption of super-critical CO[sub.2]. Increasing axial stress (buried depth) obstructs CO[sub.2] migration in the sample due to the increased effective stress, and this effect is more influential for low injection pressures, which indicates that high CO[sub.2] injection pressures are preferred for CO[sub.2] sequestration in deep coal seams.
Journal Article
Effect of Wettability and Permeability on Pore-Scale of CHsub.4–Water Two-Phase Displacement Behavior in the Phase Field Model
Hydraulic measures such as hydraulic slotting and hydraulic fracturing are commonly used in coal seam pressure relief and permeability enhancement. Two-phase flow patterns of CH[sub.4]–water in pore-sized coal seams after hydraulic measures are critical to improve gas extraction efficiency. The phase field module in COMSOL Multiphysics™ 5.4 and the classical ordered porous media model were used in this paper. The characteristics of CH[sub.4]–water two-phase immiscible displacement in coal seams under different capillary numbers (Ca) and viscosity ratios (M) were simulated and quantitatively analyzed. By changing the contact angle of the porous media, the flow patterns of CH[sub.4]–water two-phase in coal with different wettability were simulated. Results show that wettability significantly affects the displacement efficiency of CH[sub.4]. Additionally, by constructing a dual-permeability model to simulate the varying local permeability of the coal, the flow patterns of different Ca and M in dual-permeability media were further investigated. It is found that CH[sub.4] preferentially invades high-permeability regions, and the displacement efficiency in low-permeability regions increases with higher Ca and M, providing a reference for gas extraction from coal seams after hydraulic measures.
Journal Article
Preparation and Performance Evaluation of COsub.2 Foam Gel Fracturing Fluid
The utilization of CO[sub.2] foam gel fracturing fluid offers several significant advantages, including minimal reservoir damage, reduced water consumption during application, enhanced cleaning efficiency, and additional beneficial properties. However, several current CO[sub.2] foam gel fracturing fluid systems face challenges, such as complex preparation processes and insufficient viscosity, which limit their proppant transport capacity. To address these issues, this work develops a novel CO[sub.2] foam gel fracturing fluid system characterized by simple preparation and robust foam stability. This system was optimized by incorporating a thickening agent CZJ-1 in conjunction with a foaming agent YFP-1. The results of static sand-carrying experiments indicate that under varying temperatures and sand–fluid ratio conditions, the proppant settling velocity is significantly low. Furthermore, the static sand-carrying capacity of the CO[sub.2] foam gel fracturing fluid exceeds that of the base fluid. The stable and dense foam gel effectively encapsulates the proppant, thereby improving sand-carrying capacity. In high-temperature shear tests, conducted at a shear rate of 170 s[sup.−1] and a temperature of 110 °C for 90 min, the apparent viscosity of the CO[sub.2] foam gel fracturing fluid remained above 20 mPa·s after shear, demonstrating excellent high-temperature shear resistance. This work introduces a novel CO[sub.2] foam gel fracturing fluid system that is specifically tailored for low-permeability reservoir fracturing and extraction. The system shows significant promise for the efficient development of low-pressure, low-permeability, and water-sensitive reservoirs, as well as for the effective utilization and sequestration of CO[sub.2].
Journal Article
Study on properties of permeable brick
The performance research and preparation methods of different kinds of permeable brick are analyzed and summarized, which shows the wide application prospect of permeable brick.
Journal Article
Identity, structure, and function of the mitochondrial permeability transition pore: controversies, consensus, recent advances, and future directions
The mitochondrial permeability transition (mPT) describes a Ca2+-dependent and cyclophilin D (CypD)-facilitated increase of inner mitochondrial membrane permeability that allows diffusion of molecules up to 1.5 kDa in size. It is mediated by a non-selective channel, the mitochondrial permeability transition pore (mPTP). Sustained mPTP opening causes mitochondrial swelling, which ruptures the outer mitochondrial membrane leading to subsequent apoptotic and necrotic cell death, and is implicated in a range of pathologies. However, transient mPTP opening at various sub-conductance states may contribute several physiological roles such as alterations in mitochondrial bioenergetics and rapid Ca2+ efflux. Since its discovery decades ago, intensive efforts have been made to identify the exact pore-forming structure of the mPT. Both the adenine nucleotide translocase (ANT) and, more recently, the mitochondrial F1FO (F)-ATP synthase dimers, monomers or c-subunit ring alone have been implicated. Here we share the insights of several key investigators with different perspectives who have pioneered mPT research. We critically assess proposed models for the molecular identity of the mPTP and the mechanisms underlying its opposing roles in the life and death of cells. We provide in-depth insights into current controversies, seeking to achieve a degree of consensus that will stimulate future innovative research into the nature and role of the mPTP.
Journal Article
Purified F-ATP synthase forms a Ca2+-dependent high-conductance channel matching the mitochondrial permeability transition pore
The molecular identity of the mitochondrial megachannel (MMC)/permeability transition pore (PTP), a key effector of cell death, remains controversial. By combining highly purified, fully active bovine F-ATP synthase with preformed liposomes we show that Ca
2+
dissipates the H
+
gradient generated by ATP hydrolysis. After incorporation of the same preparation into planar lipid bilayers Ca
2+
elicits currents matching those of the MMC/PTP. Currents were fully reversible, were stabilized by benzodiazepine 423, a ligand of the OSCP subunit of F-ATP synthase that activates the MMC/PTP, and were inhibited by Mg
2+
and adenine nucleotides, which also inhibit the PTP. Channel activity was insensitive to inhibitors of the adenine nucleotide translocase (ANT) and of the voltage-dependent anion channel (VDAC). Native gel-purified oligomers and dimers, but not monomers, gave rise to channel activity. These findings resolve the long-standing mystery of the MMC/PTP and demonstrate that Ca
2+
can transform the energy-conserving F-ATP synthase into an energy-dissipating device.
The molecular identity of the mitochondrial megachannel (MMC)/permeability transition pore (PTP), a key effector of cell death, remains controversial. Here authors demonstrate that the membrane embedded bovine F-ATP synthase elicits Ca2 + -dependent currents matching those of the MMC/PTP.
Journal Article
Molecular mechanisms and consequences of mitochondrial permeability transition
Mitochondrial permeability transition (mPT) is a phenomenon that abruptly causes the flux of low molecular weight solutes (molecular weight up to 1,500) across the generally impermeable inner mitochondrial membrane. The mPT is mediated by the so-called mitochondrial permeability transition pore (mPTP), a supramolecular entity assembled at the interface of the inner and outer mitochondrial membranes. In contrast to mitochondrial outer membrane permeabilization, which mostly activates apoptosis, mPT can trigger different cellular responses, from the physiological regulation of mitophagy to the activation of apoptosis or necrosis. Although there are several molecular candidates for the mPTP, its molecular nature remains contentious. This lack of molecular data was a significant setback that prevented mechanistic insight into the mPTP, pharmacological targeting and the generation of informative animal models. In recent years, experimental evidence has highlighted mitochondrial F1Fo ATP synthase as a participant in mPTP formation, although a molecular model for its transition to the mPTP is still lacking. Recently, the resolution of the F1Fo ATP synthase structure by cryogenic electron microscopy led to a model for mPTP gating. The elusive molecular nature of the mPTP is now being clarified, marking a turning point for understanding mitochondrial biology and its pathophysiological ramifications. This Review provides an up-to-date reference for the understanding of the mammalian mPTP and its cellular functions. We review current insights into the molecular mechanisms of mPT and validated observations — from studies in vivo or in artificial membranes — on mPTP activity and functions. We end with a discussion of the contribution of the mPTP to human disease. Throughout the Review, we highlight the multiple unanswered questions and, when applicable, we also provide alternative interpretations of the recent discoveries.Mitochondrial permeability transition — mediated by the opening of the so-called mitochondrial permeability transition pore — causes abrupt flux of low molecular weight solutes across the generally impermeable inner mitochondrial membrane. Recent studies provide new insights into the molecular nature and mechanisms of the mitochondrial permeability transition pore and the physiological consequences of its opening.
Journal Article
The Mitochondrial Permeability Transition Pore—Current Knowledge of Its Structure, Function, and Regulation, and Optimized Methods for Evaluating Its Functional State
The mitochondrial permeability transition pore (MPTP) is a calcium-dependent, ion non-selective membrane pore with a wide range of functions. Although the MPTP has been studied for more than 50 years, its molecular structure remains unclear. Short-term (reversible) opening of the MPTP protects cells from oxidative damage and enables the efflux of Ca2+ ions from the mitochondrial matrix and cell signaling. However, long-term (irreversible) opening induces processes leading to cell death. Ca2+ ions, reactive oxygen species, and changes in mitochondrial membrane potential regulate pore opening. The sensitivity of the pore to Ca2+ ions changes as an organism ages, and MPTP opening plays a key role in the pathogenesis of many diseases. Most studies of the MPTP have focused on elucidating its molecular structure. However, understanding the mechanisms that will inhibit the MPTP may improve the treatment of diseases associated with its opening. To evaluate the functional state of the MPTP and its inhibitors, it is therefore necessary to use appropriate methods that provide reproducible results across laboratories. This review summarizes our current knowledge of the function and regulation of the MPTP. The latter part of the review introduces two optimized methods for evaluating the functional state of the pore under standardized conditions.
Journal Article