Download or read book Transport of Particles and Particle bound Compounds Through Saturated Porous Media written by Stéphane Kamangou Ngueleu and published by . This book was released on 2013 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Transport Through Porous Media written by Laura M. McDowell-Boyer and published by . This book was released on 1985 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrodynamic Controls on Particle Transport Through Heterogeneous Porous Media Technical Progress Report written by and published by . This book was released on 1993 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sophisticated models of the movement of particles, particularly bacteria and viruses, through porous media have been developed, but have met with limited success when compared to field observations some argue that the poor predictive capabilities of the models are due in part to the fact that most of the sophisticated models are tied to an assumptions of homogeneity within the flow field. In previous work, the structure of random percolation fields has been investigated and suggests application of percolation theory to heterogeneous porous media. One conclusion from this study as applied to particle transport is that as the distribution of pore throat sizes takes on variation in the third dimension, the probability of finding a continuous flow path with large throat size increases. One interpretation of this work, within the current context, leads to an argument that a saturated medium will become more open to transport of particles as the medium takes on three dimensional structure. The central hypothesis of the current project is therefore be stated: Particles which are suspended within the pore fluids of media demonstrating three-dimensional heterogeneities will be transported at higher average velocities and with less trapping than particles which are suspended in the pore fluids of media demonstrating one- or two-dimensional heterogeneities. This dependence on dimension is a function of the dimensional character of the heterogeneity, the length scales of the heterogeneity, the size of the particles, the hydrodynamics of the flow field, the degree of saturation of the medium, and the medium/particle interaction.
Download or read book Discrete Particle Transport in Porous Media written by Joon Sik Yoon and published by . This book was released on 2005 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) The entrapment mechanism was physical interlocking on surface roughness and physical straining at the contact points. Particle sedimentation and particle re-entrainment as a result of flow field perturbations were the main mechanisms contributing to the hindrance of particles. Changes in the concentrations of particles that were entrapped or hindered were observed with distance from the particle injection point. These changes, which became more significant as the fluid velocity decreased, were attributed to particle size distribution effects. Experiments conducted with an upward pore fluid velocity supported the hypothesis that particle entrapment and hindrance are driven by gravity. The comparison of the experimental results with particle transport models based on macroscopic mass balance equations demonstrated some of the short-comings of these models. Drainage tests performed using the geotechnical centrifuge and the new visualization technique e also provided initial insight into discrete particle behavior in an unsaturated porous medium. The results of these tests show that particles were scavenged by the air-water interface, adsorbed on the air-water interface of the pendular rings, and were retained by film straining. Thus, it is believed that the visualization technique developed during this work can be used to further investigations of discrete particle transport behavior in partially saturated porous media.
Download or read book Toxicological Profile for Polycyclic Aromatic Hydrocarbons written by and published by . This book was released on 1995 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bioavailability of Contaminants in Soils and Sediments written by National Research Council and published by National Academies Press. This book was released on 2003-05-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.
Download or read book The Role of Colloidal Systems in Environmental Protection written by Monzer Fanun and published by Elsevier. This book was released on 2014-02-08 with total page 715 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Role of Colloidal Systems in Environmental Protection describes the importance of colloids in many applications that contribute to environmental protection, including drinking water and wastewater treatment, heavy metal remediation, treatment of radioactive materials, corrosion, and energy conversion. Knowledge of the physical and chemical composition of colloids is important to understand and accurately model the relevant processes. The book familiarizes the reader with the technological features of the application of colloids in environmental protection, and provides chemical engineers, researchers, and scientists in academic and corporate communities with the latest developments in this field. Each chapter covers the whole spectrum of the relevant science, from the fundamentals to applications. Provides the applied technological features of colloids in environmental protection Gives insight into the use of bio-solid colloids as contaminant carriers Covers the natural occurrence of biosurfactants in the environment and their applications Provides information on the use of nanoparticles for environmental applications Chapters written by recognized and respected experts in the field from all over the world
Download or read book Plant Microbes Engineered Nano particles PM ENPs Nexus in Agro Ecosystems written by Pardeep Singh and published by Springer Nature. This book was released on 2021-03-22 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a collection of cross-disciplinary research, with contributions addressing all key features of the plant/microbe/ENP nexus in agro-ecosystems. The uptake, transport and transformation of nanoparticles in plants have attracted more and more attention in the past several years. Especially, the impact of Engineered Nanoparticles (ENPs) on bioprocesses; low-, medium- and high-level dose responses in the microbial community of soil; and long-, medium- and short-term exposure responses, particularly microbial nitrogen transformations, are just a few of the aspects involved. Since ENPs are used in many industries, including cosmetics, agriculture, medicine, food technology and waste management, their transport through biogeochemical cycles is an important focus of many studies today. Specifically, ENP–microbe interaction has been analysed with regard to disease treatment for plants; it plays a vital role in disease inhibition by releasing metal ions that act through many pathways – e.g. reactive oxygen species (ROS) generation, DNA transformation and disruption of the cell cycle – to stop cell growth in the pathogen. Due to these properties, ENPs are also used as slow release or delayed release pesticides and fungicides, and as carrier systems for growth-promoting hormones. Despite their multiple uses in various industries, the negative effects of ENPs are still a major concern for the scientific community and consumers alike. For example, their transport to various food chains has been reported to have adverse effects. This raises a degree of doubt concerning a rapidly growing scientific field with major applications in many industries. From a sustainable development perspective and particularly to ensure food security in light of the uncertainty accompanying climate change, it is imperative to address this divergence by focusing on the plant/microbe/ENP nexus.
Download or read book Transport Phenomena in Porous Media written by Yasuaki Ichikawa and published by Springer Science & Business Media. This book was released on 2012-02-10 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents an integrated perspective of the wide range of phenomena and processes applicable to the study of transport of species in porous materials. In order to formulate the entire range of porous media and their uses, this book gives the basics of continuum mechanics, thermodynamics, seepage and consolidation and diffusion, including multiscale homogenization methods. The particular structure of the book has been chosen because it is essential to be aware of the true properties of porous materials particularly in terms of nano, micro and macro mechanisms. This book is of pedagogical and practical importance to the fields covered by civil, environmental, nuclear and petroleum engineering and also in chemical physics and geophysics as it relates to radioactive waste disposal, geotechnical engineering, mining and petroleum engineering and chemical engineering.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book How Tobacco Smoke Causes Disease written by United States. Public Health Service. Office of the Surgeon General and published by . This book was released on 2010 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report considers the biological and behavioral mechanisms that may underlie the pathogenicity of tobacco smoke. Many Surgeon General's reports have considered research findings on mechanisms in assessing the biological plausibility of associations observed in epidemiologic studies. Mechanisms of disease are important because they may provide plausibility, which is one of the guideline criteria for assessing evidence on causation. This report specifically reviews the evidence on the potential mechanisms by which smoking causes diseases and considers whether a mechanism is likely to be operative in the production of human disease by tobacco smoke. This evidence is relevant to understanding how smoking causes disease, to identifying those who may be particularly susceptible, and to assessing the potential risks of tobacco products.
Download or read book Microplastics in Water and Wastewater written by Hrissi K. Karapanagioti and published by IWA Publishing. This book was released on 2019-09-15 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the topic of microplastics in water and wastewater. The chapters start with introductory issues related to the growing interest in the scientific community on microplastics and the human water cycle and point out where the microplastics could interact with water. The subsequent chapters examine evidence of the microplastic presence in freshwater, such as in both rivers and lakes, in freshwater biota, and hazardous chemicals associated with microplastics in such systems. Another set of chapters discuss the presence of microplastics in wastewater: their sources; their transfer through a wastewater treatment plant; the concentration of microplastics in effluents throughout the world; the plastic biomedia used in wastewater treatment plants and the effect on the surrounding environment of effluent wastewater pipes. These chapters also discuss the sampling methods, the sample treatment and analysis techniques used so far for microplastics in wastewater. Additionally, the presence of microplastics in sewage sludge and in soils irrigated with wastewater or fertilized with sludge are discussed. The possible impact of plastics and their additives on plants, microalgae, and humans are reviewed and presented in a critical way. Finally, a chapter summarizes all the relevant regulations and initiatives that point to the necessity of a global directive for the protection of the environment from plastic and microplastic pollution. The topic of microplastics in freshwater systems and in wastewater has scarcely been studied and requires more attention. Microplastics in Water and Wastewater aims to bring these initial findings to the attention of a broader audience and especially to operators and managers of freshwater and wastewater systems. It will also be helpful to people already aware of the marine debris problem to understand the sources of microplastics in the oceans, from freshwater systems and wastewater treatment plants.
Download or read book Gas Transport in Porous Media written by Clifford K. Ho and published by Springer Science & Business Media. This book was released on 2006-10-07 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: CLIFFORD K. HOAND STEPHEN W. WEBB Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185, USA Gas and vapor transport in porous media occur in a number of important applications includingdryingofindustrialandfoodproducts,oilandgasexploration,environm- tal remediation of contaminated sites, and carbon sequestration. Understanding the fundamental mechanisms and processes of gas and vapor transport in porous media allows models to be used to evaluate and optimize the performance and design of these systems. In this book, gas and vapor are distinguished by their available states at stan- ? dard temperature and pressure (20 C, 101 kPa). If the gas-phase constituent can also exist as a liquid phase at standard temperature and pressure (e. g. , water, ethanol, toluene, trichlorothylene), it is considered a vapor. If the gas-phase constituent is non-condensable at standard temperature and pressure (e. g. , oxygen, carbon di- ide, helium, hydrogen, propane), it is considered a gas. The distinction is important because different processes affect the transport and behavior of gases and vapors in porous media. For example, mechanisms specific to vapors include vapor-pressure lowering and enhanced vapor diffusion, which are caused by the presence of a g- phase constituent interacting with its liquid phase in an unsaturated porous media. In addition, the “heat-pipe” exploits isothermal latent heat exchange during evaporation and condensation to effectively transfer heat in designed and natural systems.
Download or read book Chemical Engineering Progress written by and published by . This book was released on 2009 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Percolation Theory for Flow in Porous Media written by Allen Hunt and published by Springer Science & Business Media. This book was released on 2009-05-05 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Why would we wish to start a 2nd edition of “Percolation theory for ?ow in porous media” only two years after the ?rst one was ?nished? There are essentially three reasons: 1) Reviews in the soil physics community have pointed out that the introductory material on percolation theory could have been more accessible. Our additional experience in teaching this material led us to believe that we could improve this aspect of the book. In the context of rewriting the ?rst chapter, however, we also expanded the discussion of Bethe lattices and their relevance for “classical” - ponents of percolation theory, thus giving more of a basis for the discussion of the relevance of hyperscaling. This addition, though it will not tend to make the book more accessible to hydrologists, was useful in making it a more complete reference, and these sections have been marked as being possible to omit in a ?rst reading. It also forced a division of the ?rst chapter into two. We hope that physicists without a background in percolation theory will now also ?nd the - troductory material somewhat more satisfactory. 2) We have done considerable further work on problems of electrical conductivity, thermal conductivity, and electromechanical coupling.
Download or read book EPA Publications Bibliography written by United States. Environmental Protection Agency and published by . This book was released on 1994 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Essential Handbook of Ground Water Sampling written by David M. Nielsen and published by CRC Press. This book was released on 2006-11-27 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tremendous improvements in ground-water sampling methodologies and analytical technologies have made it possible to collect and analyze truly representative samples to detect increasingly lower levels of contaminants-now in the sub-parts-per-billion range. Though these new methods produce more accurate and precise data and are less expensive, many
