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Defects in glasses
Book Reviews MECHANICS OF MATERIALS 4TH EDITION Arehie Higdon et al. John Wiley U.S.A. Mareh 85 744 pp £48.00 ISBN: 0-471-89044-8 This is the fourth edition of an undergraduate textbook originally published twenty-five years ago. Intended as a first course in the mechanics of deformable bodies/strength of materials (the authors assume that the student already has a working knowledge of statics and calculus), in includes far more materials than could be taught in a single course. However, the method of subdivision of the subject matter allows flexibility in the selection of topics to suit particular requirements. The overall objectives of the authors are to develop an understanding of the relationships between applied loads and the resulting deformations, stresses and strains, and to establish procedures for determining the dimensions of a loaded body required to satisfy given stress and deflection limits. The first two chapters introduce the concepts of stress and strain, while chapter three describes the relationships between them with regard to material properties. The next seven chapters treat various static loading cases: axial (together with pressure vessels), torsional, flexural (with separate chapters covering stresses, deflections and statically indeterminate beams), combined loads (including a section on failure theories) and columns. Chapters eleven and twelve deal with repeated and dynamic loading, while the final chapter is devoted to connections (riveted, bolted and welded). There is a useful set of appendices, including tables of properties of engineering materials in English/U.S. and S.I. units (which are reproduced on the front and back inside covers), stress: strain diagrams for half a dozen metals, properties of selected areas and rolled steel shapes, and a table of beam deflections and slopes. There are over one thousand set problems throughout the text, and there is a section listing answers to approximately half of these.
A comprehensive thirteen-page combined author/subject matter index completes the volume. This American book (Rankine is referred to as a 'Scotch engineer') is published in a wide-page format with two-colour printing. The basic principles are illustrated by numerous worked examples throughout the text, with an overall approach emphasising the use of freebody diagrams in analysing the loadings on a body. Here, the numerous illustrations are considerably enhanced by use of the second colour. There is a mixture of units in the book, with approximately half of the examples and the set problems using S.I. units, and the rest English/U.S. units. Overall, the book is well presented and deals comprehensively with the subject matter. However, the adoption of two sets of units may be a disadvantage is a teaching text for use on this side of the Atlantic.
able potential for fibre-optic applications, and glassy selenium alloys have been used as the photoreceptor in xerox machines for many years. These materials, and many more, form the subject of this very interesting and useful boolc In any standard texts on solid-state physics, the starting point is inevitably the theoretically satisfying, but physically but almost unrealisable, state of the perfect crystal. R e a l crystals, however, are seldom perfect, but contain numerous imperfections or impurities, which, for the most part, determine and control many of their physical properties, whether they be electronic, optical or mechanical. Exactly the same situation holds for the case of glasses too, and so a knowledge of the properties of the structural defects which can exist in them is a prerequisite to an understanding of the behaviour of the glassy state as a whole. This subject, however, is woefully lacking in current solid-state physics and matB Moxley erials texts, and so the appearance of this book is most welcome. The notion of detect in a glass DEFECTS IN GLASSES appears to be a contradiction in terms at Frank L. Galeener, first sight, since the extent of structural David L. Grlseom, disorder in such materials is so large Marvin J. Weber that it might be thought that the entire Materials Research Society structure was permeated by defects. A USA 1986 defect needs to be defined in terms of a 493 pp ISBN: 0 931837-26-X reference structure, which for the case US $41.00 Outside US $46.00 of crystalline materials is the perfect Glass is a very widely used material crystal lattice, but for the case of with many applications, and has been amorphous materials, the choice of a fabricated for thousands of years, yet it reference structure is more problemis only within the last twenty years or so atical. The equivalent to the ideal that a significant understanding of the crystal lattice for the case ofcovalentlyphysical and chemical properties of the bonded, inorganic glasses is the somaterial has been gained. For the called "continuous random network", layman of course, the word glass in which short-range (chemical) order signifies only one material, namely is often preserved in terns of covitreous silica containing various alkali ordination polyhedra, which are conand alkaline earth oxide additives to nected together in a random fashion to improve its workability (viscosity) ensure that no long-range order (periodcharacteristics. However, very many icity) exists. The volume Defects in Glasses other materials can be made in a glassy (non-crystalline) state, and the actual contains the proceeding of a symand potential technological appli- posium of the same name held in cations of these materials have added December 1985 under the auspices of great impetus to the scientific study of the Materials Research Society. Forty the glassy state. Thus, for example, papers are included, and these are fluoride-based glasses have consider- divided into seven sections, dealing
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respectively with theoretical and modelling aspects, short and intermediate-range structural order, radiation-induced defects, impurities and dopants, fibres and films, gel-produced glasses and finally a section on miscellaneous properties, such as the cause of eolouring in glasses. The underlying theme of the book is the study of defects and defectcontrolled properties; a very wide range of spectroscopic techniques are utilised for this purpose, such as magnetic resonance, Mossbauer, X-ray absorption and a variety of optical spectroscopies, e.g. fluorescence, Raman scattering, etc. Many current issues of scientific and technological interest are discussed here: loss mechanisms in fluoride glasses, radiation-induced colour centres in silica glass, electronically active defects in Se-based glasses, etc. Many of the papers included in this book are sufficiently tutorial in style, however, to afford the non-specialist reader a good introduction to the field, and the copious references to the original literature will allow individual topics to be pursued easily. Although the book has been prepared from camera-ready manuscripts, the standard of presentation is high. In conclusion, this book is recommended either for those wishing to learn something of the wide range of defectcontrolled processes exhibited by glasses or for those materials science research workers already active in the field. The range of topics covered by the book is extremely wide and there is no equivalent single-volume compendium of such information available. Dr S R Elliott
PLASTICS G E A R I N G SELECTION A N D APPLICATION Clifford E. Adams Marcel Dekker Inc. U S A 1986 384 pp ISBN: 0 8247 7498 1 $59.75 (US & Canada) $71.50 (all others) The days when plastics gears could only be used for lightly loaded low speed simple applications are past. today, due to developments in the plastics industry, there are materials available which allow plastics to be used for high accuracy power tranmission gearing running at speeds
64
which were previously considered im- and although conversion factors are given, it would have been better to possible. To take advantage of this wider rationalise on one system. I suspect that scope of application, designers will the reason for this is because many of need to be aware of the new materials the tables have been taken directly from available, the changes required to manufacturer's literature; nevertheless, design methods and the implications of having tabulated data in one system of other factors such as environment, units allied to design equations in system tolerances and assembly tech- another will obviously lead to an increased possibility of errors for the niques. It is therefore timely that this com- unwary. prehensive book on the subject should Priced at $71.50 the book is not now become available. The author is an cheap but it will make a sensible and expert in the field having over 30 years' worthwhile reference for anyone who experience in gear designs. He is a Staff has an occasional need to design or Engineer with the IBM Corporation manufacture plastic gears. Those whose and has written many publications requirements are less frequent will find concerning gearing and tribology. In that the book possibly contains too 1972 he received the American Gear much information and they would be Manufacturers' Association Technical better advised to consult a specialist Division Executive Committee Award. gear maker. Since the design principles used in plastics gears are essentially the same David Hughes as those for metals, the experienced gearing engineer will probably already possess the bulk of the information contained in this book. However, the use of plastics does introduce factors such as different assembly techniques, moisture absorption and other environMODERN DEVELOPMENTS mental effects which are extremely IN P O W D E R M E T A L L U R G Y important and which could justify the V O L U M E S 15-17 purchase of the book. Edited by E.N. Aqua and The book will be of greatest benefit to C.I. Whitman engineers who have a need to design or Metal Powder Industries specify plastics gears but whose normal Federation daily work does not cover this field and Vol. 15, 831 pp it is to the author's credit that he has IBSN 0-918404-64-9 included a brief chapter on how to Vol. 16, 755 pp select and use stock off-the-shelf plasIBSN 0-918404-65-7 tics gearing since many applications Vol. 17, 921 pp may not justify moulding or machining IBSN 0-918404-66-5 special gears. Although each chapter deals with a These three volumes are the latest in a particular topic such as selection of well established series produced by the gear type, rating calculation and mat- MPIF. Like their predecessors, the erial selection, and the sequence of volumes contain the papers presented chapters is logical in relation to the at an International Powder Metallurgy procedures adopted in designing gears, Conference, held in this case in 1984 at it is a pity that the author has not Toronto. Only the papers are reproduced. included, at the beginning of the book, a There is no word of discussion. check list of the steps to be followed in The subject matter is divided between arriving at a final design. A cross the three volumes in a manner which reference from each step to the related will be familiar to those who know the table of information and design formulae series. would have made the book into a much Volume 15 is subtitled "Principles more useable design manual. and Processes". It begins with five This is the book's main drawback reports which review the state of the since, although it contains an abun- powder metallurgy industries in North dance of information, the editing and America, Japan, Italy and Europe in layout does not always allow ease of general, West Germany and the United use. Tables and diagrams are often Kingdom. Thereafter there are 51 positioned in mid sentence within the papers mostly devoted to the results of text, sometimes with sentences starting original research. These are grouped on one page being continued two pages into eight chapters, six of which are later. Also, the units used in the book concerned with production of powders are a mixture of Imperial, metric and SI and their consolidation. These papers
MATERIALS & DESIGN Vol. 8 No. 1 JANUARY/FEBRUARY 1987
A comprehensive thirteen-page combined author/subject matter index completes the volume. This American book (Rankine is referred to as a 'Scotch engineer') is published in a wide-page format with two-colour printing. The basic principles are illustrated by numerous worked examples throughout the text, with an overall approach emphasising the use of freebody diagrams in analysing the loadings on a body. Here, the numerous illustrations are considerably enhanced by use of the second colour. There is a mixture of units in the book, with approximately half of the examples and the set problems using S.I. units, and the rest English/U.S. units. Overall, the book is well presented and deals comprehensively with the subject matter. However, the adoption of two sets of units may be a disadvantage is a teaching text for use on this side of the Atlantic.
able potential for fibre-optic applications, and glassy selenium alloys have been used as the photoreceptor in xerox machines for many years. These materials, and many more, form the subject of this very interesting and useful boolc In any standard texts on solid-state physics, the starting point is inevitably the theoretically satisfying, but physically but almost unrealisable, state of the perfect crystal. R e a l crystals, however, are seldom perfect, but contain numerous imperfections or impurities, which, for the most part, determine and control many of their physical properties, whether they be electronic, optical or mechanical. Exactly the same situation holds for the case of glasses too, and so a knowledge of the properties of the structural defects which can exist in them is a prerequisite to an understanding of the behaviour of the glassy state as a whole. This subject, however, is woefully lacking in current solid-state physics and matB Moxley erials texts, and so the appearance of this book is most welcome. The notion of detect in a glass DEFECTS IN GLASSES appears to be a contradiction in terms at Frank L. Galeener, first sight, since the extent of structural David L. Grlseom, disorder in such materials is so large Marvin J. Weber that it might be thought that the entire Materials Research Society structure was permeated by defects. A USA 1986 defect needs to be defined in terms of a 493 pp ISBN: 0 931837-26-X reference structure, which for the case US $41.00 Outside US $46.00 of crystalline materials is the perfect Glass is a very widely used material crystal lattice, but for the case of with many applications, and has been amorphous materials, the choice of a fabricated for thousands of years, yet it reference structure is more problemis only within the last twenty years or so atical. The equivalent to the ideal that a significant understanding of the crystal lattice for the case ofcovalentlyphysical and chemical properties of the bonded, inorganic glasses is the somaterial has been gained. For the called "continuous random network", layman of course, the word glass in which short-range (chemical) order signifies only one material, namely is often preserved in terns of covitreous silica containing various alkali ordination polyhedra, which are conand alkaline earth oxide additives to nected together in a random fashion to improve its workability (viscosity) ensure that no long-range order (periodcharacteristics. However, very many icity) exists. The volume Defects in Glasses other materials can be made in a glassy (non-crystalline) state, and the actual contains the proceeding of a symand potential technological appli- posium of the same name held in cations of these materials have added December 1985 under the auspices of great impetus to the scientific study of the Materials Research Society. Forty the glassy state. Thus, for example, papers are included, and these are fluoride-based glasses have consider- divided into seven sections, dealing
MATERIALS & DESIGN Vol. 8 No. 1 JANUARY/FEBRUARY 1987
63
respectively with theoretical and modelling aspects, short and intermediate-range structural order, radiation-induced defects, impurities and dopants, fibres and films, gel-produced glasses and finally a section on miscellaneous properties, such as the cause of eolouring in glasses. The underlying theme of the book is the study of defects and defectcontrolled properties; a very wide range of spectroscopic techniques are utilised for this purpose, such as magnetic resonance, Mossbauer, X-ray absorption and a variety of optical spectroscopies, e.g. fluorescence, Raman scattering, etc. Many current issues of scientific and technological interest are discussed here: loss mechanisms in fluoride glasses, radiation-induced colour centres in silica glass, electronically active defects in Se-based glasses, etc. Many of the papers included in this book are sufficiently tutorial in style, however, to afford the non-specialist reader a good introduction to the field, and the copious references to the original literature will allow individual topics to be pursued easily. Although the book has been prepared from camera-ready manuscripts, the standard of presentation is high. In conclusion, this book is recommended either for those wishing to learn something of the wide range of defectcontrolled processes exhibited by glasses or for those materials science research workers already active in the field. The range of topics covered by the book is extremely wide and there is no equivalent single-volume compendium of such information available. Dr S R Elliott
PLASTICS G E A R I N G SELECTION A N D APPLICATION Clifford E. Adams Marcel Dekker Inc. U S A 1986 384 pp ISBN: 0 8247 7498 1 $59.75 (US & Canada) $71.50 (all others) The days when plastics gears could only be used for lightly loaded low speed simple applications are past. today, due to developments in the plastics industry, there are materials available which allow plastics to be used for high accuracy power tranmission gearing running at speeds
64
which were previously considered im- and although conversion factors are given, it would have been better to possible. To take advantage of this wider rationalise on one system. I suspect that scope of application, designers will the reason for this is because many of need to be aware of the new materials the tables have been taken directly from available, the changes required to manufacturer's literature; nevertheless, design methods and the implications of having tabulated data in one system of other factors such as environment, units allied to design equations in system tolerances and assembly tech- another will obviously lead to an increased possibility of errors for the niques. It is therefore timely that this com- unwary. prehensive book on the subject should Priced at $71.50 the book is not now become available. The author is an cheap but it will make a sensible and expert in the field having over 30 years' worthwhile reference for anyone who experience in gear designs. He is a Staff has an occasional need to design or Engineer with the IBM Corporation manufacture plastic gears. Those whose and has written many publications requirements are less frequent will find concerning gearing and tribology. In that the book possibly contains too 1972 he received the American Gear much information and they would be Manufacturers' Association Technical better advised to consult a specialist Division Executive Committee Award. gear maker. Since the design principles used in plastics gears are essentially the same David Hughes as those for metals, the experienced gearing engineer will probably already possess the bulk of the information contained in this book. However, the use of plastics does introduce factors such as different assembly techniques, moisture absorption and other environMODERN DEVELOPMENTS mental effects which are extremely IN P O W D E R M E T A L L U R G Y important and which could justify the V O L U M E S 15-17 purchase of the book. Edited by E.N. Aqua and The book will be of greatest benefit to C.I. Whitman engineers who have a need to design or Metal Powder Industries specify plastics gears but whose normal Federation daily work does not cover this field and Vol. 15, 831 pp it is to the author's credit that he has IBSN 0-918404-64-9 included a brief chapter on how to Vol. 16, 755 pp select and use stock off-the-shelf plasIBSN 0-918404-65-7 tics gearing since many applications Vol. 17, 921 pp may not justify moulding or machining IBSN 0-918404-66-5 special gears. Although each chapter deals with a These three volumes are the latest in a particular topic such as selection of well established series produced by the gear type, rating calculation and mat- MPIF. Like their predecessors, the erial selection, and the sequence of volumes contain the papers presented chapters is logical in relation to the at an International Powder Metallurgy procedures adopted in designing gears, Conference, held in this case in 1984 at it is a pity that the author has not Toronto. Only the papers are reproduced. included, at the beginning of the book, a There is no word of discussion. check list of the steps to be followed in The subject matter is divided between arriving at a final design. A cross the three volumes in a manner which reference from each step to the related will be familiar to those who know the table of information and design formulae series. would have made the book into a much Volume 15 is subtitled "Principles more useable design manual. and Processes". It begins with five This is the book's main drawback reports which review the state of the since, although it contains an abun- powder metallurgy industries in North dance of information, the editing and America, Japan, Italy and Europe in layout does not always allow ease of general, West Germany and the United use. Tables and diagrams are often Kingdom. Thereafter there are 51 positioned in mid sentence within the papers mostly devoted to the results of text, sometimes with sentences starting original research. These are grouped on one page being continued two pages into eight chapters, six of which are later. Also, the units used in the book concerned with production of powders are a mixture of Imperial, metric and SI and their consolidation. These papers
MATERIALS & DESIGN Vol. 8 No. 1 JANUARY/FEBRUARY 1987