- Email: [email protected]
34)
292
which the magnitudes and pathways of the contact force propagation are shown superimposed on a computer-simulated drawing of the bed. There are also comparisons of experimental and simulated data for example, in a paper on chute flows. This topic is addressed in a number of papers including one employing Monte Carlo simulation. In addition, there is a paper describing experimental data in which existing rheological models are evaluated on the basis of granular temperature measurements and directly measured normal and shear stresses. It is of interest that Coulombic wall boundary conditions were obtained in contradiction to current theories of simple shear flows. Rapid flows are also treated theoretically in a paper on the radial flow of granular materials which will be of interest to those concerned with hopper flows. In soil mechanics, flexible membranes are used in an attempt to apply welldefined uniform boundary stresses. The more familar rigid boundaries result in a distribution of the normal and shear stresses and hence the interface constraint has to be decoupled from the bulk response in order to obtain useful materials information. These cleverly designed flexible membrane tests are described, and in particular, some of the practical problems involved which result in large changes in the stress-strain behaviour depending on the boundary constraints. There is clearly considerable potential for applying these techniques to wet particulate solids which are of general interest to the particle technologist. Stereology is included in an account that comes to some useful practical conclusions such as the estimation of imposed strain histories from the structural anisotropy. There is also a review of the various approaches to the characterisation of the local geometry in a random packing of particles by such methods as the radial distribution function and Voronoi cells. An analysis is described of the volume changes associated with triaxial compression or extension of elastic spheres where the contact mechanics is assumed to be of the Hertz-Mindlin type. Experimental data are presented for rubber discs on an air table subjected to different deformation states in order to measure co-ordination entropy and void entropy. Finally in the area of dense assemblies, there is a study that attempts to relate the average number of particle contacts
and the magnitudes of the contact forces to the velocity of shear wave propagation. Experimental measurements of this type would be of considerable value for characterising particle systems and the changes arising from applied deformations. In summary, this volume contains many readable papers of high quality that are relevant to some aspects of particle technology. It is in camera-ready form with only a one-page introductory preface and no index. This format has the advantage for conference proceedings of rapid publication and reducing cost but neither has been achieved in this case. It is a pity that an account of the discussions of the papers is not included which would have been of much interest to those of us who did not attend the Seminar. There are many aspects of soil mechanics that have a wider relevance but present difficulties in terminology, etc., to the non-specialist. The editors could have attempted to make a larger proportion of the volume more easy to assimilate for the non-specialist reader. This could have been accomplished in a variety of ways. For example, a more thoughtful ordering of the papers or sectionalisation would have been helpful. A better appreciation of the contributions would also have been possible if an extended preface had been included that described more of the background, the significant areas of progress and the expected directions of future research. Despite these comments, the volume is a unique collection of research papers that allow soil mechanics and particle technology to be viewed from a common perspective. M. J. ADAMS
Powder and Bulk Solids Handling Processes; Instrumentation and Control (Chemical Industries Series/34) by Koichi Iinoya, Hiroaki Masuda and Kinnosuke Watanabe, published by Marcel Dekker Inc., New York, 1988,296 pp., $86.00 (U.S.A. and Canada), $102.00 (all other countries), ISBN: O-8247-7971-1
The authors’ objectives in this book are (i) to assist engineers and scientists in understanding and applying principles associated with the on-line measurement of parameters important in powder-handling processes;
293
(ii) to promote the development of new instruments; (iii) to provide a textbook for an advanced undergraduate or graduate course. The first two chapters provide a brief review of various powder-handling operations and processes and of operating variables which must be measured if process control is to be achieved. Chapter 3 is devoted to a survey of techniques for taking representative samples from static and moving beds of particulate matter and from pneumatic transport lines. The major portion of the book is concerned with the application of 13 physical or chemical phenomena in the design of sensors used for indirect, or inferential, measurements in powder-handling processes. These phenomena include: the absorption and scattering of various types of radiation; other electromagnetic, electrostatic, piezoelectric and acoustic phenomena; pressure drop; Doppler effect; statistical phenomena utilised in correlation measurement techniques; the mechanics of particulate materials. Each of Chapters 4 - 12 is devoted to a discussion of the principles of measurement and of on-line sensing devices associated with the measurement of an important process variable, i.e., powder-flow rate; particle concentration in gas-solid suspensions; level of solids in storage vessels; particle size; moisture content; pressure in static and moving beds of solids and in pneumatic transport systems; temperature of particles; viscosity of solid-liquid suspensions. The last of these is the weakest chapter in the book. It is impossible, in the space of a few pages, to deal with the wide range of rheological state exhibited by systems of industrial and commercial importance. In each chapter, emphasis is placed on summarising the basic principles which can be utilised in sensor design and application. Essential equations and relationships are given but in the majority of cases, in this quite small book, there is no opportunity to show how these equations are derived. Throughout the text there are comments concerning precautions which should be observed when considering practical application of a particular principle of measurement.
However, the combination of theoretical and experimental information is, by itself, insufficient to enable the reader confidently to proceed with the design or installation of an on-line measurement device. It is necessary to obtain a more complete understanding of assumptions and simplifications made in deriving the essential equations. One must hope that the quoted bibliography can provide the necessary information. It would be difficult completely to achieve the authors’ three objectives in a balanced, analytical manner in a book of 296 pages. The authors have produced a text which is easy to read and which is adequately illustrated with simplified line diagrams. There are very few solecisms, which is particularly praiseworthy for people writing in a foreign language. It is perhaps understandable that a considerable proportion of the bibliography is concerned with technical articles and books published in Japan, but it is rather surprising that a relatively small selection of post-1980 publications is quoted. There are some quite trifling, but distracting, deficiencies in the proof-reading. Somehow, it is disconcerting to read that Lord Rayleigh was submitting articles to the Philosophical Magazine as recently as 1982. The book identifies the wide range of intriguing problems which must be solved in order to control solids-handling processes. In addition, it provides confirmation of the need to develop an integrated community of academic and industrial scientists and engineers, from many disciplines in order to make rapid, effective advances in the subject of particulate technology. It would be very encouraging if the subject were taught, at undergraduate or graduate level, in sufficient depth to justify use of this book. It is probable that this quite expensive summary of principles will find a limited market within the U.K. A companion volume is now needed to deal in much more detail with the practical, industrial matters including safety - which must also be taken into account when designing and installing on-line measurement equipment in the major solids-handling processes. G. F. EVENSON
which the magnitudes and pathways of the contact force propagation are shown superimposed on a computer-simulated drawing of the bed. There are also comparisons of experimental and simulated data for example, in a paper on chute flows. This topic is addressed in a number of papers including one employing Monte Carlo simulation. In addition, there is a paper describing experimental data in which existing rheological models are evaluated on the basis of granular temperature measurements and directly measured normal and shear stresses. It is of interest that Coulombic wall boundary conditions were obtained in contradiction to current theories of simple shear flows. Rapid flows are also treated theoretically in a paper on the radial flow of granular materials which will be of interest to those concerned with hopper flows. In soil mechanics, flexible membranes are used in an attempt to apply welldefined uniform boundary stresses. The more familar rigid boundaries result in a distribution of the normal and shear stresses and hence the interface constraint has to be decoupled from the bulk response in order to obtain useful materials information. These cleverly designed flexible membrane tests are described, and in particular, some of the practical problems involved which result in large changes in the stress-strain behaviour depending on the boundary constraints. There is clearly considerable potential for applying these techniques to wet particulate solids which are of general interest to the particle technologist. Stereology is included in an account that comes to some useful practical conclusions such as the estimation of imposed strain histories from the structural anisotropy. There is also a review of the various approaches to the characterisation of the local geometry in a random packing of particles by such methods as the radial distribution function and Voronoi cells. An analysis is described of the volume changes associated with triaxial compression or extension of elastic spheres where the contact mechanics is assumed to be of the Hertz-Mindlin type. Experimental data are presented for rubber discs on an air table subjected to different deformation states in order to measure co-ordination entropy and void entropy. Finally in the area of dense assemblies, there is a study that attempts to relate the average number of particle contacts
and the magnitudes of the contact forces to the velocity of shear wave propagation. Experimental measurements of this type would be of considerable value for characterising particle systems and the changes arising from applied deformations. In summary, this volume contains many readable papers of high quality that are relevant to some aspects of particle technology. It is in camera-ready form with only a one-page introductory preface and no index. This format has the advantage for conference proceedings of rapid publication and reducing cost but neither has been achieved in this case. It is a pity that an account of the discussions of the papers is not included which would have been of much interest to those of us who did not attend the Seminar. There are many aspects of soil mechanics that have a wider relevance but present difficulties in terminology, etc., to the non-specialist. The editors could have attempted to make a larger proportion of the volume more easy to assimilate for the non-specialist reader. This could have been accomplished in a variety of ways. For example, a more thoughtful ordering of the papers or sectionalisation would have been helpful. A better appreciation of the contributions would also have been possible if an extended preface had been included that described more of the background, the significant areas of progress and the expected directions of future research. Despite these comments, the volume is a unique collection of research papers that allow soil mechanics and particle technology to be viewed from a common perspective. M. J. ADAMS
Powder and Bulk Solids Handling Processes; Instrumentation and Control (Chemical Industries Series/34) by Koichi Iinoya, Hiroaki Masuda and Kinnosuke Watanabe, published by Marcel Dekker Inc., New York, 1988,296 pp., $86.00 (U.S.A. and Canada), $102.00 (all other countries), ISBN: O-8247-7971-1
The authors’ objectives in this book are (i) to assist engineers and scientists in understanding and applying principles associated with the on-line measurement of parameters important in powder-handling processes;
293
(ii) to promote the development of new instruments; (iii) to provide a textbook for an advanced undergraduate or graduate course. The first two chapters provide a brief review of various powder-handling operations and processes and of operating variables which must be measured if process control is to be achieved. Chapter 3 is devoted to a survey of techniques for taking representative samples from static and moving beds of particulate matter and from pneumatic transport lines. The major portion of the book is concerned with the application of 13 physical or chemical phenomena in the design of sensors used for indirect, or inferential, measurements in powder-handling processes. These phenomena include: the absorption and scattering of various types of radiation; other electromagnetic, electrostatic, piezoelectric and acoustic phenomena; pressure drop; Doppler effect; statistical phenomena utilised in correlation measurement techniques; the mechanics of particulate materials. Each of Chapters 4 - 12 is devoted to a discussion of the principles of measurement and of on-line sensing devices associated with the measurement of an important process variable, i.e., powder-flow rate; particle concentration in gas-solid suspensions; level of solids in storage vessels; particle size; moisture content; pressure in static and moving beds of solids and in pneumatic transport systems; temperature of particles; viscosity of solid-liquid suspensions. The last of these is the weakest chapter in the book. It is impossible, in the space of a few pages, to deal with the wide range of rheological state exhibited by systems of industrial and commercial importance. In each chapter, emphasis is placed on summarising the basic principles which can be utilised in sensor design and application. Essential equations and relationships are given but in the majority of cases, in this quite small book, there is no opportunity to show how these equations are derived. Throughout the text there are comments concerning precautions which should be observed when considering practical application of a particular principle of measurement.
However, the combination of theoretical and experimental information is, by itself, insufficient to enable the reader confidently to proceed with the design or installation of an on-line measurement device. It is necessary to obtain a more complete understanding of assumptions and simplifications made in deriving the essential equations. One must hope that the quoted bibliography can provide the necessary information. It would be difficult completely to achieve the authors’ three objectives in a balanced, analytical manner in a book of 296 pages. The authors have produced a text which is easy to read and which is adequately illustrated with simplified line diagrams. There are very few solecisms, which is particularly praiseworthy for people writing in a foreign language. It is perhaps understandable that a considerable proportion of the bibliography is concerned with technical articles and books published in Japan, but it is rather surprising that a relatively small selection of post-1980 publications is quoted. There are some quite trifling, but distracting, deficiencies in the proof-reading. Somehow, it is disconcerting to read that Lord Rayleigh was submitting articles to the Philosophical Magazine as recently as 1982. The book identifies the wide range of intriguing problems which must be solved in order to control solids-handling processes. In addition, it provides confirmation of the need to develop an integrated community of academic and industrial scientists and engineers, from many disciplines in order to make rapid, effective advances in the subject of particulate technology. It would be very encouraging if the subject were taught, at undergraduate or graduate level, in sufficient depth to justify use of this book. It is probable that this quite expensive summary of principles will find a limited market within the U.K. A companion volume is now needed to deal in much more detail with the practical, industrial matters including safety - which must also be taken into account when designing and installing on-line measurement equipment in the major solids-handling processes. G. F. EVENSON