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THE FORMATION AND REACTIVITY OF SOME NITRIDES
Full text linkNitrides are reviewed generally with respect to their bonding, production (including thermodynamics and kinetics of formation) and reactivity. This is followed by a summary of the studies by previous workers on the formation and reactivity of the particular nitrides, which are the subject of the present investigation. This thesis embodies further studies on various aspects of the formation and reactivity of nitrides of some Group II-IV elements. They include nitrides of more active metals such as calcium and magnesium, and of less active ones such as titanium and zirconium
AN EXPERIMENTAL STUDY OF ELECTRON SPIN RESONANCE IN SYNTHETIC DIAMOND
Full text linkThis thesis is divided into five chapters. The first chapter begins with a discussion of the basic principles of electron spin resonance and concludes with a description of the theoretical interpretation of electron spin resonance spectra in terms of the Spin Hamiltonian. The first part of the second chapter is a general discussion of the physical properties of diamond and includes reasons for the classification of diamond into various types. The second part of the chapter is devoted to a brief historical survey of the developments in the production of synthetic diamond. The final part of the chapter is an outline of the experiments which have led to the identification of nitrogen as a major impurity in natural and synthetic diamond. The third chapter combines and describes some of the experimental studies which have been made on diamond using the technique of electron spin resonance. Particular emphasis is placed on theories which have been put forward to explain the electron spin resonance signals associated with substitutional nitrogen in natural diamond. Electron spin resonance associated with synthetic diamond is discussed under a separate heading. The fourth chapter is devoted entirely to a description of the experiments carried out in this work and is concerned mainly with electron spin resonance from five different types of commercially available synthetic diamond. Those resonances, which are due to the nitrogen and ferromagnetic impurities, are shown to depend markedly on the nature of the diamond as well as its temperature. Experiments on samples which have been treated either by heating or crushing or by a combination of both, are also described
Applications of Mass Spectrometry to Organic Geochemistry
Full text linkHow did life originate? Modern evolutionary theories postulate a continuum extending from abiotically formed macromolecules to those capable of reproducing themselves and mutating in a manner which can be considered characteristic of the processes of metabolism, growth, reproduction, sensitivity, and evolution. In this sense, life consists of a small segment of possible chemical reactions. The basic element of these reactions, carbon, is unique because of its ability to form four equivalent sp³ bonds. The strength of the s character is essential for the formation of stable polymers, while the ability to form four bonds permits the greatest degree of structural complexity and thus maximum possible specificity
Quantitative comparisons between time domain speech fundamental frequency estimation algorithms,
No full textIsolation and Structure Determination of Certain Acidic Components from California Petroleum
Full text linkThe acidic constituents of petroleum are called naphthenic acids. The basic process for the isolation of these acids from petroleum involves extraction of the oil with an alkali and acidification of the aqueous extract with a mineral acid to liberate the organic acids. This product contains not only carboxylic acids, but also significant amounts of phenols and hydrocarbons. The name naphthenic acids was suggested long ago by Markownikoff (2), because the early investigation of these acids indicated that they are a mixture of alicyclic acids. Subsequent work showed that these acids do not consist entirely of alicyclic acids but also contain straight - chain and branched-chain acids, yet the name naphthenic acids is still in use for the total acidic constituents of petroleum
DISRUPTION OF THE ALUMINOSILICATE LATTICE BY ACID FLUORIDE SOLUTIONS
Full text linkThe disruption of the aluminosilicate crystal lattice by aqueous fluoride solutions has been studied. The effect of reaction time, fluoride concentration, pH, and temperature on the reaction have been investigated. The stoichiometric exchange of hydroxyls by fluoride ions in kaolinite and muscovite at pH 7 and below was extremely doubtful. Disruption of the aluminosilicate crystal lattice was thought to be the predominant reaction over the acid pH range
THE SETTLEMENT FACTOR IN THE RURAL PROBLEMS OF NORTH-EAST ENGLAND
Full text linkMuch attention has been focussed in recent years on the changing distribution of population in North-east England since the Industrial Revolution. In the introduction to his paper on this subject, J. W. House mentions many of the forces which are still in the process of complicating the earlier relatively simple factor of the drift of population from the countryside to the towns. The impacts of international trade systems, the consequences of government economic policies towards both industry and agriculture, the effects of two world wars, and the increased mobility through improved transport are just a few of the elements which must now be considered when making a study of the rural areas
THE STRUCTURAL RELATIONSHIPS OF SOME GLYCINE POLYMERS
Full text linkThe Polyglycines are of interest because they are related to nylon and the polyamides, and to the proteins. They resemble nylon in having amine, -NH₂, end groups, and the chains are formed through peptide, C0-NH- linkages. The known Polyglycines are not fibre forming, as products with the required degree of polymerisation have not been prepared, they have a low degree of polymerisation, about 10-20 is the usually recorded value for the number average degree of polymerisation. The degree of polymerisation of the fibre forming polyamides is about 200. The polyglycines may be regarded as the simplest proteins, in that they only contain one amino-acid species, and this is the simplest one