The world population in 1930 was 2 billion. It reached 3 billion in 1960, stands at 4. 6 billion today, and is expected to reach 6 billion by the end of the century. The food and fiber needs of such a rapidly increasing population are enormous. One of the most basic resources, perhaps the most basic of all, for meeting those needs is the Soil. There is an urgent need to improve and protect this resource on which the future of mankind directly depends. We must not only learn how to use the soil to furnish our immediate needs, but also ensure that the ability of the soil to sustain food production in the future is unimpaired. This is indeed a mammoth task; a 1977 United Nations survey reported that almost one-fifth of the world's cropland is now being steadily degraded. The diversity of soil makes it necessary for research to be conducted in many locations. There are basic principles, however, that are universal. This series, Advances in Soil Science, presents clear and concise reviews in all areas of soil science for everyone interested in this basic resource and man's influence on it. The purpose of series is to provide a forum for leading scientists to analyze and summarize the available scientific information on a subject, assessing its importance and identifying additional research needs. But most importantly, the contributors will develop principles that have practical applications to both developing and developed agricultures.

This book consists essentially of a collection of papers that were contributed to a national meeting held in Houston, Texas, in 1983. The papers contained herein cover a wide range of electro- chemical engineering topics and should serve as useful starting points in the design of electrochemical cells. The editor would like to thank the authors for their contribu- tions and patience and the typists, Mrs. Susan 'Firth and Mrs. Jeri Saulsbury, for their efforts. Also, the editor would like to thank Mr. T. Nguyen and Ms. M. A. Nictrolson for their help in preparing the index of this book. R. E. White v CONTENTS Design and Development of Electrochemical Chlor-Alkali Cells * * * * * * * * * 1 S. N. Chatterjee A Simple Model of a Diaphragm - Type Chlorine Cell 25 R. E. White, J. S. Beckerdite, and J. Van Zee Design Principles for Chlorine Membrane Cells 61 K. H. Simmrock Hydroxyl Ion Migration, Chemical Reactions, Water Transport and Other Effects as Optimizing Parameters in Cross-, Co- and Countercurrently Operated Membrane Cells for the Chlor/Alkali Electrolysis . *******. **** 89 K. H. Simmrock Hydraulic Modelling as an Aid to Electrochemical Cell Design. 115 I. Wardle Calculating Mechanical Component Voltage Drops in 123 Electrochemical Cells * * * * I. Wardle Electrolysis Cell Design for Ion Exchange Membrane Chlor-Alkali Process * * * * * * * * * * * * 135 M. Seko, A. Yomiyama, and S.

Soil remains one of the most important, yet most abused, natural resources on the planet. Responsible management of soil and associated water resources plays a critical role in the survival and prosperity of many nations around the world.

"Principles and Practice of Soil Science," Fourth Edition provides a current and comprehensive introduction to soil science for students in the fields of environmental and agricultural science, ecology, soil and land management, natural resource management and environmental engineering. The text focuses on the fundamental concepts of how soils function and how this functioning is vital to productive and environmentally benign soil use.

The Fourth Edition of this classic text includes:
Fully updated coverage of all the major aspects of soil science, from the soil habitat to processes in the soil environment and management for sustainable production.
Discussion of soil management and environmental impacts.
Emphasis on the applications of soil science to the solution of practical problems in soil and land management.
Real world examples drawn from the author's international experience in the field.
A thoroughly updated art package, with new colour photographs and diagrams to help students visualize key concepts.
New problem sets at the end of each chapter, designed to reinforce important principles. An answer key is provided at the end of the text.

Although designed primarily for students, "Principles and Practice of Soil Science," Fourth Edition is also an accessible reference for professional soil scientists, agronomists, ecologists, geomorphologists, engineers and land managers.