by Yu, Chak Chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 129-133). / by Yu, Chak Chung. / PREFACE --- p.i / ACKNOWLEDGMENT --- p.iv / ABSTRACT --- p.v / Chapter 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Barkhausen effect --- p.2 / Chapter 1.2 --- Magnetoacoustic emission --- p.4 / Chapter 1.3 --- Methods of measurements --- p.5 / Chapter 1.3.1 --- Magnetization of a sample --- p.6 / Chapter 1.3.2 --- Signal detection --- p.8 / Chapter 1.3.3 --- Signal processing --- p.9 / Figures for chapter1 --- p.11 / References --- p.14 / Chapter 2 --- MAGNETIC PHENOMENA AND THEORIES --- p.17 / Chapter 2.1 --- Magnetostriction --- p.17 / Chapter 2.1.1 --- Spontaneous magnetostriction --- p.18 / Chapter 2.1.2 --- Saturation magnetostriction --- p.19 / Chapter 2.1.3 --- Field induced magnetostriction --- p.20 / Chapter 2.1.4 --- Magnetostriction at an angle θ to the magnetic field --- p.21 / Figures for section 21 --- p.24 / Chapter 2.2 --- Domain theory --- p.26 / Chapter 2.2.1 --- Magnetic domains --- p.26 / Chapter 2.2.2 --- Magnetostatic energy --- p.27 / Chapter 2.2.3 --- Magnetization process --- p.29 / Figures for section 22 --- p.30 / Chapter 2.3 --- Domain walls and domain processes --- p.33 / Chapter 2.3.1 --- Properties of domain walls --- p.33 / Chapter 2.3.2 --- "180° and non-180° domain walls, and closure domains" --- p.34 / Chapter 2.3.3 --- Domain wall motion --- p.35 / Chapter 2.3.4 --- Reversible and irreversible domain processes --- p.36 / Chapter 2.3.5 --- Barkhausen emission and magnetoacoustic emission --- p.38 / Figures for section 23 --- p.39 / Chapter 2.4 --- Hindrances to wall motion --- p.43 / Chapter 2.4.1 --- Residual stress --- p.43 / Chapter 2.4.1.1 --- Dislocation --- p.44 / Chapter 2.4.1.2 --- Magnetostriction --- p.45 / Chapter 2.4.1.3 --- Plastic deformation --- p.46 / Chapter 2.4.2 --- Inclusions --- p.47 / Chapter 2.4.3 --- "Domain nucleation, annihilation, and wall motion" --- p.48 / Figures for section 24 --- p.50 / References --- p.55 / Chapter 3 --- MEASUREMENT OF BARKHAUSEN EMISSION AND MAGNETOACOUSTIC EMISSION FROM A FRACTURED STEEL BAR --- p.57 / Chapter 3.1 --- Introduction --- p.57 / Chapter 3.2 --- Experiments --- p.58 / Chapter 3.3 --- Results and discussions --- p.60 / Chapter 3.3.1 --- BE and MAE profiles --- p.60 / Chapter 3.3.2 --- Defects --- p.61 / Chapter 3.3.3 --- Elongated grains --- p.62 / Chapter 3.3.4 --- Effect of annealing --- p.63 / Chapter 3.4 --- Conclusions --- p.64 / Figures and table for chapter3 --- p.66 / References --- p.70 / Chapter 4 --- NONDESTRUCTIVE INSPECTION OF A FRACTURED NICKEL BAR BY BARKHAUSEN AND MAGNETOACOUSTIC EMISSIONS --- p.71 / Chapter 4.1 --- Introduction --- p.71 / Chapter 4.2 --- Experiments --- p.72 / Chapter 4.3 --- Results --- p.73 / Chapter 4.4 --- Discussions --- p.74 / Chapter 4.4.1 --- Barkhausen emission --- p.74 / Chapter 4.4.2 --- Magnetoacoustic emission --- p.75 / Chapter 4.4.3 --- Comparison of nickel and mild steel --- p.77 / Chapter 4.5 --- Conclusions --- p.78 / Figures and table for chapter4 --- p.81 / References --- p.83 / Chapter 5 --- DETERMINATION OF THE ROLLING DIRECTION OF ELECTROLYTIC ZINC-COATED STEEL PLATE BY BARKHAUSEN EMISSION --- p.84 / Chapter 5.1 --- Introduction --- p.84 / Chapter 5.2 --- Experiments --- p.85 / Chapter 5.3 --- Results --- p.86 / Chapter 5.4 --- Discussions --- p.87 / Chapter 5.4.1 --- BE profiles 、 --- p.87 / Chapter 5.4.2 --- Effects of hardness and defects --- p.89 / Chapter 5.5 --- Conclusions --- p.90 / Figures for chapter5 --- p.91 / References --- p.97 / Chapter 6 --- MAGNETIC MEASUREMENTS MADE ON A NICKEL PLATE WITH HIDDEN HOLE --- p.98 / Chapter 6.1 --- Introduction --- p.98 / Chapter 6.2 --- Experiments --- p.99 / Chapter 6.3 --- Results and discussions --- p.100 / Chapter 6.3.1 --- Barkhausen emission --- p.100 / Chapter 6.3.2 --- Magnetoacoustic emission --- p.102 / Chapter 6.4 --- Conclusions --- p.103 / Figures for chapter6 --- p.105 / Chapter 7 --- CONCLUSIONS AND SUGGESTIONS FOR FURTHER STUDIES --- p.114 / APPENDIX --- p.118 / Chapter A1 --- Experimental setup for BE measurement --- p.118 / Chapter A2 --- Experimental setup for MAE measurement --- p.119 / Chapter A3 --- Specifications and models of the equipment used in the experiments --- p.120 / Chapter A4 --- List of figures --- p.121 / BIBLIOGRAPHY --- p.129