Автор: Z.R.Wayne
Издательство: Elsevier Science and Technology Books
Год издания: 1991
isbn: 0444883258
Количество страниц: 173
Язык: english
Формат: PDF
This book is a comprehensive treatment of the elastic volumetric response of sandstones to variations in stress. The theory and data presented apply to the deformations that occur, for example, due to withdrawal of fluid from a reservoir, or due to the redistribution of stresses caused by the drilling of a borehole. Although the emphasis is on reservoir-type sandstones, results and methods discussed are also applicable to other porous rocks. Part One concerns the effect of stress on deformation and discusses porous rock compressibility coefficients. Elasticity theory is used to derive relationships between the porous rock compressibility coefficients, the porosity, and the mineral grain compressibility. Theoretical bounds on the compressibility coefficients are derived. The concept of effective stress coefficients is examined, as is the integrated form of the stress-strain relationships. Undrained compression and induced pore pressures are treated within the same general framework. Part One is concluded with a brief, elementary introduction to Biot's theory of poroelasticity. All the results in Part One are illustrated and verified with extensive references to published compressibility data. Part Two deals with the relationship between pore structure and compressibility, and presents methods that permit quantitative prediction of the compressibility coefficients. Two- and three-dimensional models of tubular pores, spheroidal pores, and crack-like "grain boundary" voids are analyzed. A critical review is made of various methods that have been proposed to relate the effective elastic moduli (bulk and shear) of a porous material to its pore structure. Methods for extracting pore aspect ratio distributions from stress-strain data or from acoustic measurements are presented, along with applications to actual sandstone data. Part Three is a brief summary of experimental techniques that are used to measure porous rock compressibilities in the laboratory. The information contained in this volume is of interest to petroleum engineers, specifically those involved with reservoir modeling, petroleum geologists, geotechnical engineers, hydrologists and geophysicists.
Автор: Katerina P.Svoboda, Andrew D.Syred
Издательство: Microscopix Publications
Год издания: 2000
isbn: 0953846105
Количество страниц: 62
Язык: english
Формат: PDF (scan)
Aromatic and medicinal plants arc used in the food. flavour, perfumery. pharmaceutical and healthcarc industries. The ir usc is expected to increase every year due to a consumer-led trend towards natura l foods. food and cosmetic additives and complimentary med icine including aromathcrapy. Many branches of industry are searching for alternative. cleaner antimicrobial, antibiot ic. antioxidant and crop-protection agents. The possibility of utilising volatile oils is being investigated as it has been known since antiquity that they possess biological activities. During the last decade many books have been written about herbs and spices. chemical constituents found in various plant families and the ir uses.
Автор: L.Henkin, A.Dold, B.Eckmann
Издательство: Springer-Verlag
Год издания: 1981
isbn: 0387108815
Количество страниц: 327
Язык: english
Формат: PDF
This volume is devoted to a comprehensive treatment of certain settheoretical structures which consist of fields of sets enhanced by additional fundamental operations and distinguished elements. The treatment is largely self-contained.
Автор: Will Murray
Издательство: Capstone Publishing Limited
Год издания: 2004
Количество страниц: 208
Язык: english
Формат: PDF
The forces of history are at work and we can now rip up the rule book that served society through the 20th century. In our world of frightening uncertainty there have never been greater challenges faced nor a greater divide between our hopes for the future and their fulfi lment. The new magnetic fi eld and force of world politics, a world with national governments no longer in control, distorts the compass point. We know we are all global citizens but we are no longer sure about the direction of due north. Goodbye industrial economy, hello global knowledge economy. Goodbye the state running things, hello Global Joe Citizen empowered by the technology- driven changes in the fi rst years of the 21st century and with a mobility beyond the wildest dreams of those who brought us into this world. Yes, I do mean us, fellow global citizens.
Автор: Albrecht Messerschmidt
Издательство: John WIley & Sons
Год издания: 2007
isbn: 3527313966
Количество страниц: 307
Язык: english
Формат: PDF
Written by one of the most significant contributors to the progress of protein crystallography, this practical guide contains case studies, a troubleshooting section and pointers on data interpretation. It covers the theory, practice and latest achievements in x-ray crystallography, such that any researcher in structural biology will benefit from this extremely clearly written book. Part A covers the theoretical basis and such experimental techniques as principles of x-ray diffraction, solutions for the phase problem and time-resolved x-ray crystallography. Part B includes case studies for different kinds of x-ray crystal structure determination, such as the MIRAS and MAD techniques, molecular replacement, and the difference Fourier technique.
Автор: Nicholas Eastaugh, Valentine Walsh
Издательство: Elsiver Butterworth Heinemann
Год издания: 2004
isbn: 0750645539
Количество страниц: 450
Язык: english
Формат: PDF
Polarised light microscopy is perhaps the most widely applied analytical technique currently used for the identification of historical pigments. Despite the advent of newer methods, polarised light microscopy has maintained a place in this field as a routine and effective approach to the determination of the compounds to be found on painted artefacts. Consequently it may be surprising that no dedicated atlas of pigments has ever been published to support the researcher wishing to carry out such work.
Автор: David R.Riddle
Издательство: CRC
Год издания: 2007
isbn: 0849338182
Количество страниц: 414
Язык: english
Формат: PDF
Studies of brain aging have certainly (dare we say it) come of age. The past two to three decades produced a striking increase in experimental investigations of the neurobiological basis of brain aging and of aging-related changes in neural and cognitive function. The public’s interest in experimental gerontology has grown as the public has become more “gray,” with both average age and life expectancy increasing in most developed countries. Driving the specific interest in the aging nervous system is the recognition that increased longevity has little appeal for most unless it is accompanied by maintenance of cognitive abilities. Indeed, if one searches the popular press or the Internet for information on aging, or for products that are purported to slow the aging process or limit its effects, one concludes that maintaining brain function may be the most important concern of older individuals.
Автор: A.Mulero
Издательство: Springer
Год издания: 2008
isbn: 3540787666
Количество страниц: 591
Язык: english
Формат: PDF
In our days, it seems natural using a system of hard bodies perturbed by intermolecular potentials for the modeling of the thermodynamic properties of fluids. In fact, it seems so natural that one hardly notices the misuse of the term ‘intermolecular potential’ in the previous phrase to refer to the ‘interhard- body-potential’ purported to exist for the modeling of fluids. The reason for this tacit acceptance is that, in our mental models for fluids, we identify molecules with hard bodies, almost as a primitive concept. The question then naturally arises: Was it always this way? Or, perhaps, was there a time when scientists did not recognize the existence of molecules? Could it be possible that there was a time when scientists would not accept the use of a system formed by hard bodies as the supporting structure for the modeling of fluids? It is not easy to imagine that less than one hundred years ago, the existence of atoms and molecules was still under discussion.
Автор: German Deyev, Dmitriy Deyev
Издательство: Taylor & Francis/CRC
Год издания: 2006
isbn: 0849398835
Количество страниц: 426
Язык: english
Формат: PDF
The industry is currently applying highly diverse welding processes. However, the main technological process applied in manufacture of weldments is fusion welding. Fusion welding is used to join practically all metals and alloys of similar and dissimilar materials of any thickness. In the application of fusion welding, the parts are joined either by melting of the parts’ edges or as a result of simultaneous melting of the base and additional (electrode) metal. A weld pool forms from the metal melt, its subsequent solidification, proceeding without application of external pressure, leads to the formation of the weld. Depending on the kind of the applied heat source, a distinction is made between the following fusion welding processes: electric arc, electron beam, electroslag, laser, and gas welding. Irrespective of the actual welding process applied, the main aim of any process is producing a sound welded joint. This is only possible if a sufficiently comprehensive allowance is made for the main physicochemical processes proceeding in the welding zone.
Автор: P.M.Jordan
Издательство: Elsevier
Год издания: 1991
isbn: 0444892850
Количество страниц: 323
Язык: english
Формат: PDF
The study of the structure and function of tetrapyrrolic compounds has excited the interests of organic chemists, biochemists, botanists and other biologists for more than a hundred years. The structures of most naturally occurring porphyrins were first elucidated by the efforts of Hans Fischer, and great progress was made in our knowledge of chlorophyll by Stoll and Willstatter by applying the best current methods of organic chemistry. The next major advance was made by biochemists who used newly available isotopes of carbon and nitrogen to tackle the formation of porphyrins in biological systems. This was started by the discovery by Shemin and Rittenberg that, of all the amino acids, glycine specifically supplied the nitrogen atoms of protoporphyrin IX. This led to the elucidation of one of the major pathways for the synthesis of 5-aminolaevulinic acid, and ultimately to the origin of all the atoms in protoporphyrin IX. During this period conclusive evidence was also produced that chlorophyll and bacteriochlorophyll are formed in a series of reactions in which protoporphyrin IX is anessential intermediate.
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