Elsevier bv okt 2000 (6 Ergebnisse)

Buch. Zustand: Neu. Neuware - Volume 22 of Research in Organizational Behavior continues the tradition of innovation and theoretical development with eight diverse papers. Most of these papers present theory and propositions that make linkages between different levels of analysis.

Buch. Zustand: Neu. Neuware - This book considers the different concepts of hydrophile-lipophile balance (HLB) of surfactants and solid particles and the main physicochemical properties of surfactant and solid interfaces which are used to definite the hydrophile-lipophile balance. The book comprehensively analyses all interfacial and bulk properties of surfactants used for the determination of HLB (such as interfacial tension, distribution coefficient, adsorption, surface pressure, surfactants solubility, structure characteristics, distribution between heteropolar phases, micellar formation, chromatographic characteristics, phase separation in emulsions, phase inversion temperature, formation of three phase systems).The central point of the book is the energetic interpretation of the balance, i.e. the hydrophile-lipophile ratio. At the same time the HLB-number systems of Griffin and Davies and other independant methods of the hydrophile-lipophile balance definitions are discussed: PIT, polarity indexes, surfactant affinity difference etc. The possibility of application of the different characteristics of the hydrophile-lipophile balance as a criterion of phase inversion in emulsions and microemulsion systems water-oil-surfactant are considered.For the first time the different methods of the hydrophile-lilophile balance definition for solid particles in compact and dispersed form are suggested by the author. The use of hydrophile-lipophile characteristics of solid particles as a criterion of phase inversion in emulsion stabilisation and for other applications is discussed.…

Buch. Zustand: Neu. Neuware - Well Testing is recognised by many operating oil and gas companies to be the most hazardous operation they routinely undertake. Therefore, it is of great importance that such operations are extremely well planned and executed.This handbook covers all the major 'Operational Aspects of Oil and Gas Well Testing' and uses a structured approach to guide the reader through the steps required to safely and effectively plan a well test operation under just about any circumstances world wide.Safety procedures and well testing recommended practices are rigorously addressed in this book, as are the responsibilities of those persons involved in well testing operations. Perforating equipment, drill stem test equipment and bottom hole pressure gauges are discussed in detail in the book. There is also a very valuable section on sub sea equipment, an area often not well understood even by experienced engineers who may have been primarily involved with land or jackup rigs. A major part of the book is the detailed coverage of the equipment and instrumentation that makes up a surface well testing package. It also covers operational and testing related problems such as, hydrates, wax and sand, and offers the reader some possible solutions. There are useful chapters on sampling, onsite chemistry, coil tubing and nitrogen operations and basic stimulation as they relate to well testing. Finally there is an extensive section of appendices covering useful engineering calculations and there is a complete example of a detailed well testing programme.…

Buch. Zustand: Neu. Neuware - Spectrophotometry enables one to determine, with good precision and sensitivity, almost all the elements present in small and trace quantities of any material. The method is particularly useful in the determination of non-metals and allows the determination elements in a large range of concentrations (from single % to low ppm levels) in various materials.In Separation, Preconcentration and Spectrophotometry in Inorganic Analysis, much attention has been paid to separation and preconcentration methods, since they play an essential role in increasing the selectivity and sensitivity of spectrophotometric methods. Separation and preconcentration methods have also been utilised in other determination techniques.Spectrophotometric methods which are widely used for the determination of the elements in a large variety of inorganic materials are presented in the book whilst separation and preconcentration procedures combined with spectrophotometry are also described. This book contains recent advances in spectrophotometry, detailed discussion of the instrumentation, and the techniques and reagents used for spectrophotometric determination of elements in a wide range of materials as well as a detailed discussion of separation and preconcentration procedures that precede the spectrophotometric detection.…

Buch. Zustand: Neu. Neuware - Applying recent advances in biological and physical sciences, food scientists have created 'novel food ingredients' enzymatically, chemically or microbiologically. Chief among these are 'novel proteins and polysaccharides' which, like the more established traditional macromolecules, can perform multifunctional roles such as thickening, stabilization, gelation or encapsulation and in this way determine to a large extent the shelf life, texture and nutritional value of natural and processed foods.Featuring the latest advances on chemistry, structure and functional properties of 'novel proteins and polysaccharides', with an emphasis on fundamental structure-function relationships, this book will be valuable to all those working in product development and fundamental food research.…

Buch. Zustand: Neu. Neuware - Among the numerous applications of the rare-earth elements, the field of catalysis accounts for a large number. Catalysis represents approximately 20% of the total market sales of rare earths worldwide. As a matter of fact two main applications have been prominent in the last decades: zeolite stabilization for fluid cracking catalysts, and automotive post-combustion catalytic treatment. The oldest use of rare earths in catalysis deals with the structural and chemical stabilization of the zeolites for petroleum cracking applications. For a long time this has been an area of application for non-separated rare earths. The addition of several percent of rare earths in the pores of the zeolite results in a strong surface acidity, which is essential for an efficient conversion of high-weight molecules into lighter species, like low-octane fuel, even in the very aggressive conditions of the petroleum industry. The popular demand for high-quality air in spite of the traffic congestion in large cities resulted in larger and larger constraints in the emission exhaust from cars. Thus highly efficient catalysts have had to be designed, and due to the combination of its redox properties and very good thermal stability, cerium oxide has been since the beginning, early in the 1980s, a major component of the three-way catalysts (TWC) now used in all modern gasoline cars. The future of rare earths in catalysis is probably bright. The fact that approximately 400 patents are applied for yearly in the area since 1992 is an illustration of a very active area. Usage of rare earths in catalysis is expected to grow due to their highly specific properties. Instead of the physical propertiesused in electronic applications, one deals now with redox properties, water and thermal stability, coordination numbers and so forth. The rare earths are so specific in these properties that their use can hardly be avoided, not only for the beauty of academic studies but a.…