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Showing 1 to 20 of 27 for “"Permeability coefficient"”.
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Quantifying passive drug transport across lipid membranes
… quantitative information about the membrane permeability of drugs. In this Thesis, we develop a novel optofluidic permeability assay that allows us to quantify the permeability coefficient of drugs crossing lipid membranes. Lipid vesicles are used as model systems and drug molecules are …
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Investigation of the Dimensional Stability in DSP Cement Paste
… and the elastic properties of the paste. A permeability-based mechanism was proposed to quantitatively explain the observed thermal deformation, and was used successfully to model the delayed contraction and calculate the permeability coefficient of mature, dense cement paste in the order 10 …
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Strength and water permeability of concrete containing coal bottom ash as cement and fine aggregate replacement material
… Afterward, compressive strength and water permeability tests were evaluated at 7, 28, 56, 90 and 180 days respectively. It was observed that concrete containing GCBA and UGCBA for all percentage replacement were found to be higher compressive strength and water permeability coefficient as …
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The integration of non-destructive test methods in the South African Durability Index approach
… RC [reinforced concrete] structures. The oxygen permeability index (OPI) test is being standardised in South Africa, and has been implemented in a large scale project by the South African National Roads Agency Limited (SANRAL). However, the semi-invasive nature of the test method (due to core …
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Metal complexes of anti-tubercular drugs
… of anti-tubercular drugs to improve the permeability and bioavailability of the drugs. The anti-tubercular drugs isoniazid (ISO), ethambutol (EMB), para-aminosalicylic acid (PAS), rifampicin (RFN) and pyrazinecarboxamide (PZA) were used in this study. Since the solubility and hence …
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Rheological properties of candle filter deposits at elevated temperatures and pressures
… system was modeled by Darcy's law, yielding a permeability coefficient that varied as a function of porosity between 0, at an approximate porosity of 0.885, and 3.7 x 10-11 m2.;As part of an on-going project, PFBC (Pressurized Fluidized Bed Combustor) simulated filter cakes were prepared, …
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Synthesis and Characterization of Linear and Crosslinked Mono-Sulfonated Poly(arylene ether sulfone)s for Reverse Osmosis Applications
… at 400 psi and 2000 ppm NaCl with a water permeability coefficient of 0.57 x 10-6 cm2/s. The salt rejection remained greater than 99% when a mixed salt feed source containing Ca2+ in the 0-200 ppm range together with the 2000 ppm NaCl was introduced. Crosslinked mono-sulfonated oligomers …
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The mechanics of cell-seeded collagen hydrogels
… to measure the mechanical properties, namely permeability and stiffness, of HepG2 cell-seeded collagen hydrogels. Confined compression testing in conjunction with biphasic theory modelling was utilised to provide measures of these mechanical parameters of interest. Different cell seeding …
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Transport phenomena in hydrogel membranes
… copolymer membranes and determining the permeability coefficient of salts with a fixed anion. The results were discussed in terms of the `free-volume' model of permeation and the water structuring of the polymer backbone. The ability of ionophores to selectively modulate the permeation of …
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Sublingual drug delivery: In vitro-in vivo correlation
… However, the derived absorption parameter permeability coefficient was similar in in vitro and in vivo system for caffeine: (2.10±0.22)×10 –5 , (2.06±0.47)×10 –5 ; Naproxen: (1.91±0.44)×10 –5 , (2.34±0.26)×10 –5 ; Propranolol: (2.93±0.52)×10 –5 , (3.51±0.75)×10 –5 ; Verapamil: …
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Calcium and strontium ionic flux of lipid bilayers
… measured for the several membranes. The water permeability coefficient of lecithin membrane was comparable with that of dog red blood cell. Ca++ fluxes across membranes showed the order of cerebroside-lecithin>lecithin> cerebroside>ceramide>tripalmitin, and sr++ fluxes followed the order: …
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Mechanism(s) involved in the transport of Fenretinide across Caco-2 monolayers
… Electrical Resistance (TEER) and antipyrine permeability (transcellular marker) were not affected after treatment with 0.5% PVP K 25 on the apical side. The apparent permeability coefficient (P<sub>app</sub>) of fenreti nide was extremely low [(8.8 ± 0.5) x 10<sup>-8</sup> cm/sec] even in the …
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Thermal and transport properties of layered silicate nanomaterials subjected to extreme thermal cycling
… and content of nanoclays were tested and their permeability coefficient was calculated. The permeability values obtained for the different formulations assisted to understand the transport properties of nanoclay modified composites. In addition to this, thermal characterization was performed …
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Concrete carbonation prediction for varying environmental exposure conditions
… of the concrete. A carbonation model with permeability coefficient (k) from the Oxygen Permeability Index (OPI) test as the key material variable was developed by Salvoldi (2010) using accelerated carbonation test data. The main aim of this research is to further develop the carbonation …
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Transport of oxygen in roots of rice (Oryza sativa L.) and of water in developing grape berries (Vitis vinifera L.)
… has been developed to measure the oxygen permeability coefficient of the outer part of root (OPR) of rice. Perfusion of aerenchyma of root segments with mixtures of O2/N2 of known oxygen concentration and at the same time measuring radial losses of oxygen allowed quantification of the …
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Flow Mechanisms and Transient Pressure Analysis Study For Multi-Stage Fractured Horizontal Wells In Shale Gas Reservoirs
… has the characteristics of low porosity and low permeability. Therefore, the fractured horizontal well technology has been widely used in shale gas reservoir development. At the same time, more and more attention has been paid to the study of seepage mechanism. At present, conventional research …
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The permeability of fine grained soils: an investigation into unconventional methods of measurement in the laboratory
… used British Standard constant head triaxial permeability (BS) test, for permeability testing of fine grained soils, is known to have a relatively long test duration. Consequently, a reduction in the required time for a soil permeability test provides potential cost savings, to the …
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Mikrostruktur-basierte Simulation des Feuchtetransports in Zement- und Sandstein
… as the original pore space. In case of permeability Bernoulli's law is applied to every tube in the transportation network. An arbitrary pressure difference of 1 bar is imposed between the inlet and the outlet surface of the network and the resulting mass flow is calculated by finite …
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Separation of various organic-organic and aqueous-organic solutions via pervaporation
… small, 5 g/(m^2-h) at maximum. Overall permeability coefficients for solvents studied correlate a relationship with the longest molecular solvent size. Such a correlation describes permeation of highly polar solvents such as methanol only when methanol dimerization in the highly …
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Applicazione delle tecniche elettrosmotiche alla consolidazione dei fanghi di risulta dei processi mineralurgici
… to realize barriers of consolidated and low permeability material along the perimeters and bottom of disused basin while in active basins the quick consolidation of the slurry could make it possible to accumulate a greater mass of tails and to increase the daily amount brought to the basin. …
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