Some Observations Concerning The Capture Of Sub Micron Particles By Fine Fibres In Filters
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Some Observations Concerning The Capture Of Sub Micron Particles By Fine Fibres In Filters
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Author : P. Cavanagh
language : en
Publisher:
Release Date : 1964
Some Observations Concerning The Capture Of Sub Micron Particles By Fine Fibres In Filters written by P. Cavanagh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1964 with categories.
When aerosols of sub-micron particles pass through a fibrous filter, the fibres capture some of the particles. In order to find the relative importance of various possible mechanisms of capture, a means was devised for using and observing sub-micron fibres in the form of a two-dimensional filter. With this, various aspects of filtration were examined. It was found that by far the greatest effect in causing capture of particles was the vibratory component of air flow. If the air flow was very steady, few particles were captured. If vibrations were superimposed on a steady flow, captures increased greatly. Under all conditions used, sub-micron fibres captured far more particles than seemed reasonable for their sizes compared with micron fibres. Possible reasons for this are discussed.
The Capture Of Sub Micron Aerosol Particles By Single Fine Fibres
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Author : L. G. Wilson
language : en
Publisher:
Release Date : 1970
The Capture Of Sub Micron Aerosol Particles By Single Fine Fibres written by L. G. Wilson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1970 with categories.
Apparatus is described for the direct observation of the capturing of aerosol particles by single, very thin fibres. Particles of sub-micron diameters, and fibres of similar diameters were used. Other equipment described makes possible the direct assessment of deposits on individual fibres by use of an electron microscope. By these means the nature of the flow around fibres as it depends on various aerosol and fibre parameters was studied. Also measurements were made of the capturing power of various fibres, and it was found that this may vary widely for what appear to be identical conditions. These experiments indicate that current aerosol theory for the submicron region based on simplified geometrical ideas like diffusion and direct interception is unlikely to represent the facts of fibrous aerosol filtration. Factors such as surface condition of the fibres and electrostatic effects must be included before the theory can be considered realistic. (Author).
Technical Abstract Bulletin
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Author :
language : en
Publisher:
Release Date :
Technical Abstract Bulletin written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on with Science categories.
Nanofiber Filter Technologies For Filtration Of Submicron Aerosols And Nanoaerosols
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Author : Wallace Woon-Fong Leung
language : en
Publisher: Elsevier
Release Date : 2021-10-30
Nanofiber Filter Technologies For Filtration Of Submicron Aerosols And Nanoaerosols written by Wallace Woon-Fong Leung and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-10-30 with Technology & Engineering categories.
Nanofiber Filter Technologies for Filtration of Submicron Aerosols and Nanoaerosols covers the nanoaerosols (less than 100 nanometers) to larger submicron aerosols due mostly to pollution, which are present in high number concentration in our surroundings. People are breathing these nanoaerosols daily without being aware of it. Airborne viruses from flu to coronaviruses are also nanoaerosols. During the COVID-19 pandemic, it took a long time for health authorities and the General Public to recognize the airborne transmission mode of the virus. This leads to inadequate protection and ineffective virus control strategies resulting in high infection and death rates. The book cites evidence and observations pointing to the airborne transmission mode of the coronavirus. It also discusses different filtration technologies using nanofibers to capture these aerosols for short-term filtration, where aerosols are trapped in the filter (depth filtration), and long-term filtration, where aerosols are trapped in the growing filter cake (cake filtration). This book provides a good understanding on how nanofibers, which is of size 1/1000 times that of a normal human hair, can effectively filter these tiny aerosols. NFT, organized in four sections – fundamentals, deep understanding, technologies, and application, covering comprehensively on the subject, is a valuable resource for undergraduates and graduates, engineers, researchers and practitioners in related industries. Describes technologies with insight and use basic engineering principles to build-up technologies Includes extensive clear and understandable figures and tables to enhance key concepts Uses examples throughout to explain engineering principles and interdisciplinary concepts The only book in the market focusing on nanofiber filter technologies for filtering submicron aerosols and nanoaerosols
Filtration Of Nacl And Wox Nanoparticles Using Wire Screens And Nanofibrous Filters
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Author : Raheleh Givehchi
language : en
Publisher:
Release Date : 2016
Filtration Of Nacl And Wox Nanoparticles Using Wire Screens And Nanofibrous Filters written by Raheleh Givehchi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Air categories.
Airborne nanoparticle filtration is essential for the protection of public health and the environment. The principles and fundamentals of air filtration have been validated with respect to micron particles; however, the mechanisms for airborne nanoparticle filtration are still uncertain. Conventional filtration theory states that diffusion dominates the behavior of submicron particles and that filtration efficiency increases inversely with the size of fine particles. This theory implies that nanoparticles can be effectively captured by properly designed air filters. However, some researchers have pointed out that single-digit nanosized airborne particles may behave like gas molecules upon impacting the filter media, if the kinetic energy is greater than the adhesion energy. As a result, such small nanoparticles may rebound from the filter media upon collision, in what is called thermal rebound. However, this phenomenon has not yet been observed in experimental studies, so uncertainties are still associated with the concept of thermal rebound, which itself has yet to be either proven or disproven. Despite the large amount of work done on nanoparticle filtration, there is still a gap between theory and experiments. This research aims to understand the interaction between nanoparticles and various filter media. The following tasks were done to achieve this goal: 1) Determining the performance of a scanning mobility particle sizer coupled with a Faraday cup electrometer (SMPS+E) for sizing airborne nanoparticles, 2) Implementing the nanoparticle filtration tests using wire screens for various particle number concentration distributions, 3) Developing a new thermal rebound model to determine the particle size at which thermal rebound occurs, 4) Characterizing PVA nanofibrous filters for nanoparticle removal, 5) Evaluating the effects of particle concentration on the filtration of PVA nanofibrous filters. Before conducting any filtration efficiency measurement, the performance of the scanning mobility particle sizer coupled with a Faraday cup electrometer (SMPS+E, GRIMM 7.860) was analyzed for NaCl and WOx particles at various particle number concentration distributions. The effects of instrument parameters, including the sheath air flow rate and sample air flow rate on particle number concentration distribution and on the lower and upper particle size detection limits were investigated theoretically and experimentally. For both types of nanoaerosol particles, the measurement of particle number concentration distribution depended on the selection of sheath air and sample air flow rate ratio, which depended on the initial particle concentrations and aerosol flow rate. Due to the high resolution of GRIMM SMPS+E for particle classification, no mobility shift was observed. The filtration efficiencies of nanoparticles with a broad size range and concentrations were then determined for uncharged micron-sized stainless-steel wire screens. Results showed that the filtration efficiency of WOx nanoparticles depends on particle number concentration distribution. For particles smaller than the mode size, the filtration efficiency followed the conventional theoretical model; however, the filtration efficiency deviated from that conventional model for larger particles. This result is likely due to the different morphology of WOx particles, which affects both particle charging and measurement performance. The next step was to develop a new filtration model by considering the possibility of thermal rebound effect. Theoretical analysis showed that, when nanoparticles collide on a solid filter media, it is more likely for plastic deformation to occur than elastic deformation does. Therefore, the nanoparticle filtration model was developed based on the assumption of plastic deformation of nanoparticles upon impaction to the surface of the filter media. Furthermore, results showed that the probability of thermal rebound increases inversely with relative humidity, which attenuates capillary force. The interactions between nanoparticles and various filter media are characterized by surface loading. Electrospun PVA nanofibrous filters were thus fabricated, then characterized in terms of fiber size distribution by SEM analysis using an automated tool, and their filtration performances were evaluated using NaCl nanoparticles. The higher the applied voltage and tip-to-collector distance and the shorter the deposition time, the higher the quality factors of the nanofibrous filters. Furthermore, the filter quality factor can be greatly improved by stacking up single layer filters made in a short deposition time. The electrospun PVA nanofibrous filters were then tested for sub-4 nm WOx particles with triple modal particle number concentration distributions at a low relative humidity (RH=2.9%). The upstream particle concentration affected the performance of nanofibrous filters, as it was higher at the lower particle concentration. The filtration efficiency for sub-2 nm particles showed that the particle critical diameter, below which thermal rebound may happen, is in the range of 1.07-1.17 nm. An analytical model was developed to predict the effects of particle concentration. Comparison between the developed model and experiments showed qualitative agreement; but more research is needed to further improve the model.
World Congress On Particle Technology 3
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Author :
language : en
Publisher: IChemE
Release Date : 1998
World Congress On Particle Technology 3 written by and has been published by IChemE this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Technology & Engineering categories.
A world conference held in this area every four years, with 1998 being the third. IChemE publishes the proceedings, and this time they are presented in CD-ROM format. Amongst the plenary contributors is Sir Harold Kroto on Buckminsterfullerenes.
Aerosols Handbook
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Author : Lev S. Ruzer
language : en
Publisher: CRC Press
Release Date : 2012-08-15
Aerosols Handbook written by Lev S. Ruzer and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-08-15 with Nature categories.
With the rapid growth of the nanotechnology industry, the need to understand the biological effects of aerosol exposure has become increasingly important. Featuring contributions by leading experts in the field, Aerosols Handbook: Measurement, Dosimetry, and Health Effects, Second Edition offers an up-to-date overview of many aspects of aerosols, f
21st Century Nanoscience A Handbook
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Author : Klaus D. Sattler
language : en
Publisher: CRC Press
Release Date : 2020-11-09
21st Century Nanoscience A Handbook written by Klaus D. Sattler and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-11-09 with Technology & Engineering categories.
21st Century Nanoscience - A Handbook: Low-Dimensional Materials and Morphologies (Volume 4) will be the most comprehensive, up-to-date large reference work for the field of nanoscience. Handbook of Nanophysics by the same editor published in the fall of 2010 and was embraced as the first comprehensive reference to consider both fundamental and applied aspects of nanophysics. This follow-up project has been conceived as a necessary expansion and full update that considers the significant advances made in the field since 2010. It goes well beyond the physics as warranted by recent developments in the field. This fourth volume in a ten-volume set covers low-dimensional materials and morphologies. Key Features: Provides the most comprehensive, up-to-date large reference work for the field. Chapters written by international experts in the field. Emphasises presentation and real results and applications. This handbook distinguishes itself from other works by its breadth of coverage, readability and timely topics. The intended readership is very broad, from students and instructors to engineers, physicists, chemists, biologists, biomedical researchers, industry professionals, governmental scientists, and others whose work is impacted by nanotechnology. It will be an indispensable resource in academic, government, and industry libraries worldwide. The fields impacted by nanophysics extend from materials science and engineering to biotechnology, biomedical engineering, medicine, electrical engineering, pharmaceutical science, computer technology, aerospace engineering, mechanical engineering, food science, and beyond.
Meteorological And Geoastrophysical Abstracts
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Author :
language : en
Publisher:
Release Date : 1972
Meteorological And Geoastrophysical Abstracts written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1972 with Cosmic physics categories.
Government Reports Announcements
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Author :
language : en
Publisher:
Release Date : 1971
Government Reports Announcements written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1971 with Technology categories.