1st Edition

Physical Properties of Plant and Animal Materials: v. 1: Physical Characteristics and Mechanical Properties

By Nuri N. Mohsenin Copyright 1971

    This collection of essays by both Western and East European experts examines the efforts to develop strategies for dealing with the environmental crisis both by governments and at the grassroots level of newly emerging green movements.

    Preface -- CHAPTER 1 IMPORTANCE -- 1.1 Physical Characteristics -- 1.2 Mechanical Properties -- 1.3 Thermal Properties -- 1.4 Electrical Properties -- 1.5 Optical Properties -- CHAPTER 2 STRUCTURE AND RETENTION OF WATER -- 2.1 Organization of the Plant Body -- 2.2 The Cell Wall -- 2.3 The Cell Contents . -- 2.4 Relationship Between Turgor Pressure and Tissue Rigidity -- 2.5 Dimensional Characteristics of Cells and Intercellular Spaces -- 2.6 Gross Structure and Chemical Composition of Selected Agricultural Products -- 2.7 Retention of Water in Biological Materials -- Sorption-desorption isotherm -- Adsorption equations -- 2.8 Selected Bibliography on Structure of Plant and Animal Products -- CHAPTER 3 PHYSICAL CHARACTERISTICS -- 3.1 Shape and Size -- 3.2 Criteria for Describing Shape and Size -- Charted standards -- Roundness -- Sphericity -- Measurement of axial dimensions -- Resemblance to geometric bodies Average projected area -- 3.3 Volume and Density -- Platform scale -- Specific gravity balance -- Specific gravity gradient tube -- Air comparison pycnometer -- Pycnometer method -- Unit bulk density of porous materials -- Radiation method -- 3.4 Porosity -- 3.5 Surface Area -- Leaf and stalk surface area -- Fruit surface area -- Egg surface area -- Specific surface in a porous pack -- CHAPTER 4 SOME BASIC CONCEPTS OF RHEOLOGY -- 4.1 Biological Systems and Mechanical Properties -- 4.2 ASTM Standard Definition of Terms Related to Mechanical Properties -- 4.3 Other Definitions Related to Mechanical Properties -- 4.4 Physical States of a Material -- 4.5 Classical Ideal Materials Ideal elastic behavior (Hookean body) Ideal plastic behavior (St. Venant body) Ideal viscous behavior (Newtonian liquid) -- 4.6 Time Effects (Viscoelasticity) -- 4.7 Rheological Models Electrical equivalence of mechanical models -- 4.8 Rheological Equations -- Total stress and total strain -- Maxwell model -- Generalized Maxwell model -- Kelvin model -- 4-element model (Burgers model) -- Generalized Kelvin model -- 4.9 Viscoelastic Characterization of Materials -- Stress-strain behavior -- Creep -- Stress relaxation -- Dynamic tests -- 4.10 Non-Newtonian Fluids and Viscometry -- Types of flow curves Viscometry -- Mechanics of flow in capillary viscometers -- Mechanics of flow in rotational viscometers -- 4.11 Selected Books on Rheology -- 4.12 List of Symbols -- CHAPTER 5 RHEOLOGICAL PROPERTIES -- 5.1 Force-Deformation Behavior -- 5.2 Stress-Strain Behavior -- Uniaxial compression -- Uniaxial tension -- Shear -- Bending -- 5.3 Elastic-Plastic Behavior -- 5.4 Evaluation of Poisson’s Ratio -- 5.5 Bulk Stress-Strain Behavior -- 5.6 Viscoelastic Behavior -- Stress relaxation behavior -- Creep behavior -- Dynamic viscoelastic behavior -- Viscoelastic characterization by compliance and strain energy methods -- 5.7 Flow of Organic Fluids -- CHAPTER 6 CONTACT STRESSES BETWEEN BODIES IN COMPRESSION -- 6.1 Hertz Problem of Contact Stresses -- 6.2 Contact Problem for Viscoelastic Bodies -- 6.3 Boussinesq Problem of Die Loading -- 6.4 Applications of Hertz and Boussinesq Techniques -- 6.5 List of Symbols -- Chapter 7 RHEOLOGY AND TEXTURE OF FOOD MATERIALS -- 7.1 Descriptive Terms -- 7.2 Classification of Methods of Texture Evaluation -- 7.3 Subjective or Sensory Measurements -- Physiological aspects -- Psychological aspects -- Mechanical aspects -- 7.4 Objective or Instrumental Measurements -- Fundamental rheological tests -- Relationship between fundamental tests and sensory evaluations -- 7.5 Imitative and Empirical Tests . -- 7.6 Texture Profile Method -- 7.7 Need for Standardization of Nomenclature and Measuring Techniques -- 7.8 Texture and Structural Mechanics of Food Materials -- 7.9 Dynamic Tests for Evaluation of Food Texture -- 7.10 Dimensional Analysis of Food Texture -- 7.11 Mechanical Tests Applicable to Food Materials -- 7.12 Firmness and Hardness -- Firmness -- Hardness -- Dynamic hardness -- 7.13 Effect of Age, Water Content and Temperature on Texture of Foods -- Chapter 8 MECHANICAL DAMAGE -- 8.1 Economic Importance -- Seeds and grains -- Fruits and vegetables -- 8.2 Causes of Mechanical Damage -- 8.3 Biological and Chemical Reactions Following Mechanical Damage -- 8.4 Terms and Definitions Related to External Damage -- 8.5 Detection and Evaluation of Mechanical Damage -- 8.6 Impact Damage -- Mechanics of impact -- Energy-absorbing capacity of cushioning materials -- Loading rate and mechanical damage -- 8.7 Damage Under Dead Load -- 8.8 Comparison of Static and Dynamic Resistance to -- Mechanical Damage -- 8.9 Vibration Damage -- 8.10 Stress-Cracking -- 8.11 Maximum Allowable Load for Agricultural Products . -- Strength of eggshell Strength of seed sand grains Strength of fruits and vegetables 8.12 List of Symbols -- Chapter 9 AERO- AND HYDRODYNAMIC CHARACTERISTICS -- 9.1 Drag Coefficient -- Friction drag Profile or pressure drag -- 9.2 Terminal Velocity -- Spherical bodies Non-spherical bodies -- Terminal velocity from drag coefficient— Reynold’s number relationship -- Terminal velocity from time-distance relationship -- 9.3 Applications to Agricultural Products -- Frontal area -- Particle orientation -- Separation from foreign materials -- Pneumatic transport and handling -- Air flow through products and drag coefficient of materials -- Other applications of aerodynamic properties -- Hydraulic transport and handling -- 9.4 List of Symbols -- CHAPTER FRICTION -- 10.1 Some Basic Concepts of Solid Friction -- The laws of friction -- Effect of load and properties of contacting bodies Effect of sliding velocity and contact surface temperature -- Effect of water film (friction and adhesion) Effect of surface roughness (directional friction coefficient) -- 10.2 Solid Friction in Agricultural Materials -- Measurement of static and kinetic coefficient of friction -- Effect of normal pressure Effect of sliding velocity Effect of surface conditioning Effect of moisture Effect of environment -- 10.3 Rolling Resistance -- 10.4 Angle of Internal Friction and Angle of Repose -- Angle of repose Angle of internal friction -- 10.5 Flow of Bulk Granular Materials -- Gravity flow in bins and hoppers Gravity flow through orifices Gravity flow through chutes Forced flow of solids -- 10.6 Pressure Distribution in Storage Structures -- Definitions of shallow bins and deep bins Pressure distribution in shallow bins Pressure distribution in deep bins -- 10.7 Pressure Distribution in Compression Chambers -- 10.8 Applications in Design of Handling and Processing Machines -- Power losses due to friction -- Screw conveyors -- Oscillating conveyors -- Forage harvesters -- Sifting on an oscillating riddle -- Grain threshing -- Fertilizer spreaders -- Design criteria for minimum mechanical injury -- 10.9 List of Symbols -- APPENDIX -- CITED REFERENCES -- NAME INDEX -- SUBJECT INDEX.

    Biography

    Nuri N. Mohsenin