Ultrasonic methods have been very popular in nondestructive testing and characterization of materials. This book deals with both industrial ultrasound and medical ultrasound. The advantages of ultrasound include flexibility, low cost, in-line operation, and providing data in both signal and image formats for further analysis. The book devotes 11 chapters to ultrasonic methods. However, ultrasonic methods can be much less effective with some applications. So the book also has 14 chapters catering to other or advanced methods for nondestructive testing or material characterization. Topics like structural health monitoring, Terahertz methods, X-ray and thermography methods are presented. Besides different sensors for nondestructive testing, the book places much emphasis on signal/image processing and pattern recognition of the signals acquired.

An impulse for writing this book has originated from the effort to sum marize and publicise the acquired results of a research team at the De partment of Automation of the Faculty of Electrical Engineering and In formatics, Slovak Technical University in Bratislava. The research team has been involved for a long time with control problems for machine production mechanisms and, in recent (approximately 15) years, its effort was aimed mostly at the control of electrical servosystems of robots. Within this scope, the members of the authors' staff solved the State Re search Task Ultrasonic sensing of the position of a robot hand, which was coordinated by the Institute of Technical Cybernetics of the Slovak Academy of Sciences in Bratislava. The problem was solved in a complex way, i.e. from a conceptual de sign of the measurement, through the measurement and evaluation sys tem, up to connection to the control system of a robot. Compensation of the atmospheric influence on the precision of measurement, as well as on the electroacoustical transducers, were important parts of the solution. The solution was aimed at using the ultrasonic pulse method which en ables the measurement of absolute 3D position coordinates, contrary to the relative position measurements by the incremental pick-ups which are standard robotic equipment.

This open access book presents established methods of structural health monitoring (SHM) and discusses their technological merit in the current aerospace environment. While the aerospace industry aims for weight reduction to improve fuel efficiency, reduce environmental impact, and to decrease maintenance time and operating costs, aircraft structures are often designed and built heavier than required in order to accommodate unpredictable failure. A way to overcome this approach is the use of SHM systems to detect the presence of defects. This book covers all major contemporary aerospace-relevant SHM methods, from the basics of each method to the various defect types that SHM is required to detect to discussion of signal processing developments alongside considerations of aerospace safety requirements. It will be of interest to professionals in industry and academic researchers alike, as well as engineering students. This article/publication is based upon work from COST Action CA18203 (ODIN - http://odin-cost.com/), supported by COST (European Cooperation in Science and Technology). COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. Our Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation.

Ultrasonic Measurement Methods describes methods used in ultrasonic measurements and covers topics ranging from radiated fields of ultrasonic transducers to the measurement of ultrasonic velocity and ultrasonic attenuation, along with the physical principles of measurements with electromagnetic-acoustic transducers (EMATs). Optical detection of ultrasound and measurement of the electrical characteristics of piezoelectric devices are also examined. Comprised of seven chapters, this volume begins with an analysis of the radiated fields of ultrasonic transducers, followed by a discussion on the measurement of ultrasonic velocity and attenuation. The next chapter describes the physical principles of measurement with EMATs and the advantages of such devices based on their couplant-free operation. Optical detection of ultrasound is then considered, together with the problem of measuring the electrical characteristics of piezoelectric resonators and standard methods for obtaining the equivalent electrical parameter values. The final chapter is devoted to ultrasonic pulse scattering in solids and highlights many fascinating examples of wave scattering, some of which are accompanied by theoretical analysis. This book will be of interest to physicists.

During the last 30 years, there has been a remarkable devel opment and increase in the number of processes and devices that utilize or emit non-ionizing radiant energies such as micro waves, a form of electromagnetic wave energy and ultrasound representative of mechanical vibration. These energies are used in all sectors of our society for military, industrial, telecommunications, medical, and consumer applications. More recently, the use of ultrasound in biology and medicine has been considerably expanded. These increases in sources of non ionizing radiant energy have resulted in growing interest on the part of government regulatory agencies, industrial and mili tary physicians, research workers, clinicians, and even environ mentalists. Although there is information on biologic effects and potential hazards to man from exposure to microwaves or ultrasound, considerable confusion and misinformation has permeated not only the public press but also some scientific and technical publications. Interest in the biologic effects of high frequency currents developed in the beginning of the present century. This was followed by the introduction of "u1trashortwave" therapy. During the latter part of World War II, the U. S. military services became interested in the possible hazards to personnel working around microwave sources, and the Office of Naval Research of the U. S. Navy began to sponsor research on the biologic effects of microwaves in 1948. In 1956, the U. S.

Medical applications of ultrasound range from therapy, foetal monitoring, diagnostic imaging and blood flow measurement, to surgery and lithotripsy. Ever since the earliest developments of medical ultrasound there has been an interest in the measurement and characterisation of the ultrasonic fields generated in these applications, either for assessment of performance of equipment or for safety. Until recently, procedures for acoustic output measurements were ill-defined, but standards are now being developed internationally by the International Electrotechnical Commission (1EC) and reliable commercial measuring equipment is becoming more widely available. The aim of this book is to introduce acoustic output measurement techniques and to provide an insight into the measurement methods. The material presented is based on a course originally run during November 1989 at the National Physical Laboratory. In addition to the lectures, the course consisted of a series of practicals to allow participants to gain experience of making measurements. Teddington, UK Roy C. Preston February 1991 Contents List of Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii List of Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 Safety of Diagnostic Ultrasonic Equipment: The Relevance of Acoustic Output Information to the Clinical User R. C. Preston 1. 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 2 The Relevance of Acoustic Output Information. . . . . . . . . . . . . 6 1. 2. 1 What Is Acoustic Output Information? . . . . . . . . . . . . . . . . . . . 6 1. 2. 2 What Is Acoustic Output Information Used For? . . . . . . . 6 1. 2. 3 Why Should You Know the Acoustic Output Levels of Your Equipment? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. 2. 4 Are Acoustic Output Levels Really that Important? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .