Microbial And Geochemical Dynamics In Soils And Their Impact On The Hydraulic Properties From Laboratory Experiments To Model Development
Download Microbial And Geochemical Dynamics In Soils And Their Impact On The Hydraulic Properties From Laboratory Experiments To Model Development PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Microbial And Geochemical Dynamics In Soils And Their Impact On The Hydraulic Properties From Laboratory Experiments To Model Development book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages.
Microbial and Geochemical Dynamics in Soils and Their Impact on the Hydraulic Properties : from Laboratory Experiments to Model Development
Most of the microorganisms on Earth are found in sophisticated colonies called biofilms. Such microbial communities may proliferate everywhere life can exist as long as nutrients are available and surface attachment is possible. Some biofilms can provide valuable services to the society or to the functioning of ecosystems, while others are potentially troublesome and may contribute to health, ecological and economic problems. Particularly, in porous media, a sound characterization of the microbial dynamics is key for the design and management of many technological applications. Literature contains a vast number of experiments and model approaches that have certainly contributed to a better understanding. However, the driving forces behind microbial proliferation in soils are not yet well understood. Difficulties mostly arise from the complex nature of the interactions between microbial pools, porous media and environmental conditions. First, microbes drive the biogeochemical processes, promoting the degradation of organic matter and contaminants. Second, the accumulation of biomass in soils alters their hydraulic properties, changing the capacity to transport and retain water and solutes. Third, organisms may deploy survival mechanisms in response to environmental stresses. On one hand, biofilm matrix helps increasing the hydration status and improving the digestive system efficiency. On the other hand, microbes may be induced into a reversible state of dormancy under unfavorable conditions. The mechanisms by which this microbial habitat is regulated and the resulting impact on the hydraulic properties frame the scope of this contribution. The main outcome of the thesis consists in a new soil microbial model framework that can be used as an explorative tool to elucidate the processes occurring in bio-amended soils. Based on extensive empirical evidence, the model includes: (i) the relevant microbial compartments that permit capturing the complexity of biofilms, (ii) some mechanisms to modulate microbial dynamics according to environmental conditions; and (iii) the feedbacks between biofilms, the soil hydraulic properties and the overall conditions in the vicinities of cells. This document is structured in five chapters. In Chapter 1 the main characteristics of microbial proliferation and its impact on soils are described. In Chapter 2, two laboratory experiments aimed at unraveling the spatiotemporal biogeochemical dynamics in soils under continuous or intermittent ponding conditions are described. Several direct and indirect measurements of biomass and activity reported evidence of microbial adaptation to the environmental circumstances. Chapter 3 presents a mechanistic model to study the impact of biomass accumulation on the variably saturated hydraulic properties of soils. Special emphasis is laid on the mechanisms behind water flow and retention. The biofilm represents bacterial cells and extracellular polymeric substances (EPS), displaying a complex channeled geometry that shrinks/swells with suction. New analytical solutions of the soil-water retention curve and the relative permeability are derived and discussed. In Chapter 4 a model that can simulate the proliferation of multi-compartment biofilms is presented. Such an approach permits unraveling the microbial dynamics in different environments and the underlying mechanisms controlling the response to stress. To achieve this, the model is equipped with indicators to monitor environmental and biological factors and react accordingly. Finally, Chapter 5 comprises a summary of the most important conclusions drawn during the course of the thesis. In general, the model is able to reproduce meaningfully a number of complex experimental processes. The most important mechanisms behind microbial and geochemical dynamics in soils and their impact on the hydraulic properties have been partially elucidated.
Fluid Dynamics in Complex Fractured-Porous Systems
Author: Boris Faybishenko
language: en
Publisher: John Wiley & Sons
Release Date: 2015-06-04
Despite of many years of studies, predicting fluid flow, heat, and chemical transport in fractured-porous media remains a challenge for scientists and engineers worldwide. This monograph is the third in a series on the dynamics of fluids and transport in fractured rock published by the American Geophysical Union (Geophysical Monograph Series, Vol. 162, 2005; and Geophysical Monograph, No. 122, 2000). This monograph is dedicated to the late Dr. Paul Witherspoon for his seminal influence on the development of ideas and methodologies and the birth of contemporary fractured rock hydrogeology, including such fundamental and applied problems as environmental remediation; exploitation of oil, gas, and geothermal resources; disposal of spent nuclear fuel; and geotechnical engineering. This monograph addresses fundamental and applied scientific questions and is intended to assist scientists and practitioners bridge gaps in the current scientific knowledge in the areas of theoretical fluids dynamics, field measurements, and experiments for different practical applications. Readers of this book will include researchers, engineers, and professionals within academia, Federal agencies, and industry, as well as graduate/undergraduate students involved in theoretical, experimental, and numerical modeling studies of fluid dynamics and reactive chemical transport in the unsaturated and saturated zones, including studies pertaining to petroleum and geothermal reservoirs, environmental management and remediation, mining, gas storage, and radioactive waste isolation in underground repositories. Volume highlights include discussions of the following: Fundamentals of using a complex systems approach to describe flow and transport in fractured-porous media. Methods of Field Measurements and Experiments Collective behavior and emergent properties of complex fractured rock systems Connection to the surrounding environment Multi-disciplinary research for different applications
Masters Theses in the Pure and Applied Sciences
Author: Wade H. Shafer
language: en
Publisher: Springer Science & Business Media
Release Date: 2012-12-06
Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Oata Analysis and Synthesis (CINOAS) * at Purdue. University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 33 (thesis year 1988) a total of 13,273 theses titles from 23 Canadian and 1 85 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 33 reports theses submitted in 1988, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.