Methods and instrument for determining the gas permeability of polymer films over a wide range of temperature and pressure differences using an IPDO-2A omegatron device for measuring partial pressures

1981 ◽  
Vol 23 (5) ◽  
pp. 1313-1317
Author(s):  
L.B. Golovanov ◽  
S.M. Stefanov ◽  
V.D. Cholakov
Keyword(s):  
Polymer Films ◽  
Gas Permeability ◽  
Partial Pressures ◽  
Wide Range ◽  
Temperature And Pressure

Empirical Model of Operating Temperature and Pressure Effect towards Pure and Binary O2/ N2 Gas Permeability in Polysulfone Membrane

2018 ◽  
Vol 777 ◽  
pp. 238-244
Author(s):  
Serene Sow Mun Lock ◽  
Kok Keong Lau ◽  
Irene Sow Mei Lock ◽  
Azmi Mohd Shariff ◽  
Yin Fong Yeong ◽  
...  
Keyword(s):  
Empirical Model ◽  
Membrane Separation ◽  
Gas Permeability ◽  
Economic Assessment ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Polysulfone Membrane ◽  
Wide Range ◽  
Temperature And Pressure ◽  
Membrane Permeance

Oxygen (O2) enriched air combustion via adaption of polymeric membranes has been proposed to be a feasible alternative to increase combustion proficiency while minimizing the emission of greenhouse gases into the atmosphere. Nonetheless, majority of techno-economic assessment on the O2 enriched combustion evolving membrane separation process are confined to assumption of constant membrane permeance. In reality, it is well known that membrane permeance is highly dependent upon the temperature and pressure to which it is operated. Therefore, in this work, an empirical model, which includes the effect of temperature and pressure to permeance, has been evaluated based on own experimental work using polysulfone membrane. The empirical model has been further validated with published experimental results. It is found that the model is able to provide an excellent characterization of the membrane permeance across a wide range of operating conditions for both pure and binary gas with determination coefficient of minimally 0.99.

Spectrophotometry of Aqueous HNO3, H2SO4, and DCIO4 from 25° to 250°C

1968 ◽  
Vol 22 (5) ◽  
pp. 545-548 ◽  
Author(s):  
W. C. Waggener ◽  
A. J. Weinberger ◽  
R. W. Stoughton
Keyword(s):  
Cell Wall ◽  
Corrosion Products ◽  
Spectral Measurements ◽  
Wide Range ◽  
General Program ◽  
Cell Window ◽  
Temperature And Pressure

Dilute nitric, sulfuric, and perchloric acids are applicable as solvents for spectrophotometry up to 250°C over the following ranges: 0 to 1.0 f HNO3 from 0.6 to 1.2 μ; 0 to 0.2 f H2SO4 from 0.25 to 1.2 μ; and 0 to 1.0 f DClO4 from 0.25 to 1.8 μ. Each of these acids reacts measurably with the titanium cell wall and the sapphire windows at rates which increase with acidity and temperature. This corrosion affects the spectral measurements as a function of time and is associated with deterioration of cell window surfaces and the presence in the sample of dissolved and suspended corrosion products. These results are part of our more general program for the development of equipment and technique for routine spectrophotometry of pure liquids and solutions over a wide range of temperature and pressure.

Porosity Control of Thermally Sprayed Ceramic Deposits

1998 ◽  
Author(s):  
P. Chraska ◽  
V. Brozek ◽  
B.J. Kolman ◽  
J. Ilavsky ◽  
K. Neufuss ◽  
...  
Keyword(s):  
Gas Permeability ◽  
Water Immersion ◽  
Thermal Spraying ◽  
Spray Parameters ◽  
Post Processing ◽  
Free Standing ◽  
Spray Process ◽  
Wide Range ◽  
Controlled Porosity ◽  
Selection Of

Abstract Porosity regulates the deposit's properties and therefore methods for its control are of a vital industrial importance. Thermal spraying can produce deposits in a wide range of porosities by selection of a spray process itself, by selection of spray parameters, feedstock size and chemistry, etc. Manufacturing of deposits with controlled porosity may be difficult if the selection of spray processes and materials is limited. Special methods of deposition or/and subsequent post processing may be therefore necessary. These methods are studied in the presented work. All spraying was done with the water-stabilized plasma (WSP®) system PAL 160. Thick deposits and free-standing parts were sprayed from alumina, zircon, metal Al and Ni powders and their combinations. Porosity was characterized by number of techniques such as gas permeability, water immersion, MIP, SEM and SANS. Mechanical properties were characterized by the Young's modulus. Special methods of deposition, such as spraying of mixtures of ceramics and metals were successfully used. Either sandwiched-structures with alternating layers of ceramics and metals were sprayed (for the sealing purpose) or mechanical mixtures of ceramic and metallic feedstock were sprayed. Several post-processing methods were used to change porosity volumes or other materials characteristics. To increase the porosity the metallic phases were subsequently removed by leaching or by annealing at temperatures above the melting point of metal. A number of sealing materials (organic and inorganic) were used to seal the pores by infiltration at ambient or higher pressures. The results show, that significant changes of porosity volume and, especially, of the gas permeability are possible. Another tested method was annealing/calcination of deposits, which resulted in an increase or decrease of porosity, depending on deposit's chemistry and annealing conditions. Results show that all used post processings are capable of significant changes of deposit microstructure and that they may be successfully applied in practice.

Thermodynamic Properties of Pure and Mixed Thermal Plasmas Over a Wide Range of Temperature and Pressure

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Omid Askari
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Fluid Dynamic ◽  
Thermal Plasmas ◽  
Statistical Thermodynamic ◽  
Reference Source ◽  
Degree Of Ionization ◽  
Wide Range ◽  
Self Consistent ◽  
Temperature And Pressure

Chemical composition and thermodynamics properties of different thermal plasmas are calculated in a wide range of temperatures (300–100,000 K) and pressures (10−6–100 atm). The calculation is performed in dissociation and ionization temperature ranges using statistical thermodynamic modeling. The thermodynamic properties considered in this study are enthalpy, entropy, Gibbs free energy, specific heat at constant pressure, specific heat ratio, speed of sound, mean molar mass, and degree of ionization. The calculations have been done for seven pure plasmas such as hydrogen, helium, carbon, nitrogen, oxygen, neon, and argon. In this study, the Debye–Huckel cutoff criterion in conjunction with the Griem’s self-consistent model is applied for terminating the electronic partition function series and to calculate the reduction of the ionization potential. The Rydberg and Ritz extrapolation laws have been used for energy levels which are not observed in tabulated data. Two different methods called complete chemical equilibrium and progressive methods are presented to find the composition of available species. The calculated pure plasma properties are then presented as functions of temperature and pressure, in terms of a new set of thermodynamically self-consistent correlations for efficient use in computational fluid dynamic (CFD) simulations. The results have been shown excellent agreement with literature. The results from pure plasmas as a reliable reference source in conjunction with an alternative method are then used to calculate the thermodynamic properties of any arbitrary plasma mixtures (mixed plasmas) having elemental atoms of H, He, C, N, O, Ne, and Ar in their chemical structure.

Numerical modeling of hydration performance for well cement exposed to a wide range of temperature and pressure

2020 ◽  
Vol 261 ◽  
pp. 119929
Author(s):  
Xuerui Wang ◽  
Baojiang Sun ◽  
Songyan Li ◽  
Zhiyuan Wang ◽  
Hao Li ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Wide Range ◽  
Temperature And Pressure ◽  
Well Cement

scholarly journals Gas Permeability of Cellulose Aerogels with a Designed Dual Pore Space System

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2688 ◽  
Author(s):  
Kathirvel Ganesan ◽  
Adam Barowski ◽  
Lorenz Ratke
Keyword(s):  
Porous Materials ◽  
Cell Walls ◽  
Gas Permeability ◽  
Pore Space ◽  
Nitrogen Adsorption ◽  
Space System ◽  
Fixed Amount ◽  
Hydrophilic Lipophilic Balance ◽  
Wide Range ◽  
The Impact

The gas permeability of a porous material is a key property determining the impact of the material in an application such as filter/separation techniques. In the present study, aerogels of cellulose scaffolds were designed with a dual pore space system consisting of macropores with cell walls composing of mesopores and a nanofibrillar network. The gas permeability properties of these dual porous materials were compared with classical cellulose aerogels. Emulsifying the oil droplets in the hot salt–hydrate melt with a fixed amount of cellulose was performed in the presence of surfactants. The surfactants varied in physical, chemical and structural properties and a range of hydrophilic–lipophilic balance (HLB) values, 13.5 to 18. A wide range of hierarchical dual pore space systems were produced and analysed using nitrogen adsorption–desorption analysis and scanning electron microscopy. The microstructures of the dual pore system of aerogels were quantitatively characterized using image analysis methods. The gas permeability was measured and discussed with respect to the well-known model of Carman–Kozeny for open porous materials. The gas permeability values implied that the kind of the macropore channel’s size, shape, their connectivity through the neck parts and the mesoporous structures on the cell walls are significantly controlling the flow resistance of air. Adaption of this new design route for cellulose-based aerogels can be suitable for advanced filters/membranes production and also biological or catalytic supporting materials since the emulsion template method allows the tailoring of the gas permeability while the nanopores of the cell walls can act simultaneously as absorbers.

scholarly journals Methane-induced haemolysis of human erythrocytes

1995 ◽  
Vol 307 (2) ◽  
pp. 433-438 ◽  
Author(s):  
H Batliwala ◽  
T Somasundaram ◽  
E E Uzgiris ◽  
L Makowski
Keyword(s):  
Diffusion Rate ◽  
Human Erythrocytes ◽  
Experimental Conditions ◽  
Detergent Concentration ◽  
Partial Pressures ◽  
Temperature Diffusion ◽  
Wide Range ◽  
Gas Molecules ◽  
High Concentrations ◽  
Cell Leakage

Human erythrocytes were exposed to high concentrations of methane and nitrogen through the application of elevated partial pressures of these gas molecules. Cell leakage (haemolysis) was measured for cells exposed to these gases under a wide range of experimental conditions. Application of methane produces haemolysis at pressures far below the hydrostatic pressures known to disrupt membrane or protein structure. The effects of changes in buffer, temperature, diffusion rate and detergents were studied. Methane acts co-operatively with detergents to produce haemolysis at much lower detergent concentration than is required in the absence of methane or in the presence of nitrogen. At sufficiently high concentrations of methane, all cells are haemolysed. Increased temperature enhances the effect. Methane produces 50% haemolysis at a concentration of about 0.33 M compared with about 7.5 M methanol required for the same degree of haemolysis.

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