Imidazole ionic liquids (ILsub.s) have good affinity and good solubility for carbon dioxide (COsub.2). Such ionic liquids, combined with polyimide membrane materials, can solve the problem that, ...today, COsub.2 is difficult to separate and recover. In this study, the ionic liquid (IL) of 1-ethyl-3-methylimidazolium tetrafluoroborate (ILsub.1), 1-pentyl-3-methylimidazolium tetrafluoroborate (ILsub.2), 1-octyl-3-methylimidazolium tetrafluoroborate (ILsub.3), and 1-dodecylimidazolium tetrafluoroborate (ILsub.4) with different contents were added to a polyimide matrix, and a series of polyimide membranes blended with ionic liquid were prepared using a high-speed mixer. The mechanical properties and gas separation permeability of the membranes were investigated. Among them, the selectivity of the PI/ILsub.3 membrane for COsub.2/CHsub.4 was 180.55, which was 2.5 times higher than the PI membrane, and its COsub.2 permeability was 16.25 Barrer, which exceeded the Robeson curve in 2008; the separation performance of the membrane was the best in this work.
Thin-film composite (TFC) membranes containing a metal–polyphenol network (MPN)-based selective layer were fabricated on a porous polyacrylonitrile support. The MPN layer was formed through ...coordination-based self-assembly between plant-based tannic acid (TA) and an Fesup.3+ ion. For the first time, we demonstrate that TFC membranes containing TA-Fesup.3+ selective layers can separate small organic solutes in aqueous media from equimolar mixtures of solutes. The effect of the assembly time on the characteristics and performance of the fabricated selective layer was investigated. An increase in the assembly time led to the formation of selective layers with smaller effective pore sizes. The tannic acid–Fesup.3+ selective layer exhibited a low rejection towards neutral solutes riboflavin and poly(ethylene glycol) while high rejections were observed for anionic dyes of orange II and naphthol green B. Permeation selectivities in the range of 2–27 were achieved between neutral and charged dyes in both single- and mixed-solute experiments, indicating the significant role of Donnan exclusion and the charge-selective nature of the membranes. The rejection efficiency improved with an increasing assembly time. Overall, this study demonstrates that the assembly time is a vital casting parameter for controlling the permeance, rejection and selectivity of thin-film composite membranes with a tannic acid–Fesup.3+ selective layer.
Experimental studies have confirmed the permeability reduction of coal samples upon the adsorption of COsub.2. However, these studies were carried out under limited experimental conditions. In this ...study, COsub.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 COsub.2 adsorption for low injection pressures. COsub.2 pressure development in the sample increases with increasing injection pressure due to the enhanced advection flux for sub-critical COsub.2 injections, while for super-critical COsub.2 injections, COsub.2 pressure development, as well as concentrations in the sample, decreases compared to sub-critical COsub.2 injections because of greater density and viscosity of super-critical COsub.2 as well as coal matrix swelling induced by the adsorption of super-critical COsub.2. Increasing axial stress (buried depth) obstructs COsub.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 COsub.2 injection pressures are preferred for COsub.2 sequestration in deep coal seams.
Study on properties of permeable brick Zhixuan, Zhang; Bin, Yang; Na, Zhu ...
Journal of physics. Conference series,
08/2021, Letnik:
1986, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
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.
In this study, polyacrylonitrile hollow fiber (PAN HF) membranes were designed and fabricated with desired morphology and permeability for low pressure-driven applications via the dry-wet ...phase-inversion spinning process. The effects of multiple design and fabrication parameters on permeation, morphology, thickness, and pore size of membranes were investigated using various techniques. Moreover, the effects of water as the nonsolvent additive, chemical composition of the bore solution, dope solution flow rate, air gap, coagulation bath temperature, and tensile ratio (take-up speed) were investigated. The addition of 3% wt. water as the nonsolvent additive into the dope solution resulted in a seventeen-times increment in the water flux up to 495 L m-2 h-1 bar-1. It showed a significant improvement in membrane porosity compared with those prepared without water nonsolvent additive. Utilization of 90% wt. of the solvent in water solution as the bore solution instead of pure water showed the most significant effect on the water flux and membrane structure among the fabrication parameters. It resulted in a reduction in threshold permeation pressure by more than ten times. The results revealed that whichever variation, including increased dope solution flow rate or coagulation bath temperature, or reduced air gap or traction, leads to promotion of membrane water flux. Still, different effects on the structure and morphology of the membranes were observed. Based on the outcomes of this study and according to the SEM images, one can conclude that outer surface pore size reduction from about 300 nm resulted in decreased water flux from 448 to 226 L m-2 h-1 bar-1, so that no pores were observed in the outer surface until 50 K magnification of the SEM image. The findings in this study provide instructive guidelines for the design and fabrication of high-performance hydrophilic PAN-based hollow fiber membranes with the desired morphology and water flux. Best ranges of investigated parameters for relatively high permeate water flux and desired membrane morphology were reported.
Developing microwave absorbers with superior low-frequency electromagnetic wave absorption properties is one of the foremost important factors driving the boom in 5G technology development. In this ...study, via a simple hydrothermal and pyrolysis strategy, randomly interleaved CoNiOsub.2 nanosheets and uniformly ultrafine CoNi nanocrystals are anchored onto both sides of a single-layered MXene. The absorption mechanism demonstrated that the hierarchical heterostructure prevents the aggregation of MXene nanoflakes and magnetic crystallites. In addition, the introduction of the double-magnetic phase of CoNiOsub.2/CoNi arrays can not only enhance the magnetic loss capacity but also generate larger void spaces and abundant heterogeneous interfaces, collectively promoting impedance-matching and furthering microwave attenuation capabilities at a low frequency. Hence, the reflection loss of the optimal absorber (M–MCNO) is −45.33 dB at 3.24 GHz, which corresponds to a matching thickness of 5.0 mm. Moreover, its EAB can entirely cover the S-band and C-band by tailoring the matching thickness from 2 to 7 mm. Satellite radar cross-section (RCS) simulations demonstrated that the M–MCNO can reduce the RCS value to below −10 dB msup.2 over a multi-angle range. Thus, the proposed hybrid absorber is of great significance for the development of magnetized MXene composites with superior low-frequency microwave absorption properties.
The constant rate of strain (CRS) oedometer test, using an imposed vertical strain rate ??.sub.I equal to 10 times the end-of-primary (EOP) vertical strain rate ??.sub.p, requiring a test duration of ...about 2 days produces reliable information on both the e versus logsigma'.sub.p relation and e versus logk.sub.v relation of soft clays and fibrous peats. An empirical correction for the strain rate effect on preconsolidation pressure leads to the EOP e versus logsigma'.sub.v relation and EOP sigma'.sub.p. The imposed vertical strain rate ??.sub.I produces excess pore-water pressures at the impervious bottom of the specimen, corresponding to u'.sub.b/sigma.sub.v values in the range of 3%-15% and allows, use of the Darcy flow equation, a reliable calculation of the coefficient of permeability. Compressibility and permeability data are from CRS and incremental loading (IL) oedometer tests on specimen quality designation (SQD) A samples of seven soft clays and two fibrous peats are presented in this paper.
Major progress has been made in defining the basis of the mitochondrial permeability transition, a Ca2+‐dependent permeability increase of the inner membrane that has puzzled mitochondrial research ...for almost 70 years. Initially considered an artefact of limited biological interest by most, over the years the permeability transition has raised to the status of regulator of mitochondrial ion homeostasis and of druggable effector mechanism of cell death. The permeability transition is mediated by opening of channel(s) modulated by matrix cyclophilin D, the permeability transition pore(s) (PTP). The field has received new impulse (a) from the hypothesis that the PTP may originate from a Ca2+‐dependent conformational change of F‐ATP synthase and (b) from the reevaluation of the long‐standing hypothesis that it originates from the adenine nucleotide translocator (ANT). Here, we provide a synthetic account of the structure of ANT and F‐ATP synthase to discuss potential and controversial mechanisms through which they may form high‐conductance channels; and review some intriguing findings from the wealth of early studies of PTP modulation that still await an explanation. We hope that this review will stimulate new experiments addressing the many outstanding problems, and thus contribute to the eventual solution of the puzzle of the permeability transition.
The mechanistic basis for the mitochondrial permeability transition (an inner membrane permeability increase that is a causative event in cell death) has puzzled mitochondrial research for 70 years. Here, we review the field and discuss recent evidence on how a Ca2+‐dependent conformational change of F‐ATP synthase and of adenine nucleotide translocator may transform these energy‐conserving devices into energy‐dissipating multiconductance channels causing the permeability transition.
The mitochondrial permeability transition (mPT) describes a Ca
-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 Ca
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 F
F
(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.
![CO[sub.2] Flow Characterist...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/2071-1050/small "CO[sub.2] Flow Characteristics in Macro-Scale Coal Sample: Effect of CO[sub.2] Injection Pressure and Buried Depth")
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![Well-Dispersed CoNiO[sub.2]...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/2079-6412/small "Well-Dispersed CoNiO[sub.2] Nanosheet/CoNi Nanocrystal Arrays Anchored onto Monolayer MXene for Superior Electromagnetic Absorption at Low Frequencies")
