Separation of a Gas Mixture Flowing Through a Long Tube at Low Pressure
Separation of a Gas Mixture Flowing Through a Long Tube at Low Pressure

Author: Richard David Present

Publisher:

Published: 1949

Total Pages: 16

ISBN-13:

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The separation of a binary gas mixture by diffusion through a capillary of radius r depends on the fact that the molecules have different masses m sub i and mean speeds v sub i. When the inlet pressure is so low that the mean free path lambda is much greater than r, the flow is diffusive and the separation factor (at zero outlet pressure) has its maximum value (m sub 1/m sub 2)(1/2). At high pressures (lambda (less than or equal r) no separation occurs. This paper treats the intermediate case (lambda approx. r) where the transfer of forward momentum from light to heavy molecules in unlike collisions equalizes the transport velocities and decreases the separation factor. As the inlet pressure rises, this effect makes the flow nonseparative before it becomes viscous. Flow equations are derived by equating the momentum acquired by the light component from the pressure gradient to the momentum lost to the wall plus that transferred to the other component. The viscous effects are treated as a small additive perturbation on the flow. The integrated flow equations express the separation factor as a function of the inlet and outlet pressures.

Inorganic Membranes Synthesis, Characteristics and Applications
Inorganic Membranes Synthesis, Characteristics and Applications

Author: R. Bhave

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 331

ISBN-13: 9401165475

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Here is the first book devoted completely to inorganic membrane separations and applications. It provides detailed information on all aspects of the development and utilization of both commercial and developmental inorganic membranes and membrane-based processes, pointing out their key advantages and limitations as separation tools. Characteristics, technological advances, and future applications of inorganic membranes are discussed in depth. An overview of the origins of these membranes provides a basis for understanding emerging technologies in the field. Coverage of thermal, chemical, surface, and mechanical properties of inorganic membranes includes discussion of pore diameter, thickness, and membrane morphology. You'll gain valuable insights into membrane modification, as well as the design and operation of membrane filtration units. Also included are sections on how to analyze mechanisms that affect flux feature models for prediction of micro- and ultrafiltration flux that help you minimize flux decline. Descriptions of cross-flow membrane filtration and common operating configurations clarify the influence of important operating parameters on system performance. Parameters influencing solute retention properties during ultrafiltration are identified and discussed or treated in detail.

Nonthermal Plasmas for Materials Processing
Nonthermal Plasmas for Materials Processing

Author: Jörg Florian Friedrich

Publisher: John Wiley & Sons

Published: 2022-07-15

Total Pages: 805

ISBN-13: 1119364760

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NONTHERMAL PLASMAS FOR MATERIALS PROCESSING This unique book covers the physical and chemical aspects of plasma chemistry with polymers and gives new insights into the interaction of physics and chemistry of nonthermal plasmas and their applications in materials science for physicists and chemists. The properties and characteristics of plasmas, elementary (collision) processes in the gas phase, plasma surface interactions, gas discharge plasmas and technical plasma sources, atmospheric plasmas, plasma diagnostics, polymers and plasmas, plasma polymerization, post-plasma processes, plasma, and wet-chemical processing, plasma-induced generation of functional groups, and the chemical reactions on these groups along with a few exemplary applications are discussed in this comprehensive but condensed state-of-the-art book on plasma chemistry and its dependence on plasma physics. While plasma physics, plasma chemistry, and polymer science are often handled separately, the aim of the authors is to harmoniously join the physics and chemistry of low-pressure and atmospheric-pressure plasmas with polymer surface chemistry and polymerization and to compare such chemistry with classic chemistry. Readers will find in these chapters Interaction of plasma physics and chemistry in plasmas and at the surface of polymers; Explanation and interpretation of physical and chemical mechanisms on plasma polymerization and polymer surface modification; Introduction of modern techniques in plasma diagnostics, surface analysis of solids, and special behavior of polymers on exposure to plasmas; Discussion of the conflict of energy-rich plasma species with permanent energy supply and the much lower binding energies in polymers and alternatives to avoid random polymer decomposition Technical applications such as adhesion, cleaning, wettability, textile modification, coatings, films, etc. New perspectives are explained about how to use selective and mild processes to allow post-plasma chemistry on non-degraded polymer surfaces. Audience Physicists, polymer chemists, materials scientists, industrial engineers in biomedicine, coatings, printing, etc.