Sunday, January 8, 2012

BOOK REVIEW - BIOLOGICAL EFFECTS OF MICROWAVES


Title: Biological Effects of Microwaves
Authors: S Baranski and P Czerski
Published by: Dowden, Hutchinson and Ross, Inc., StroudsburgPennsylvania,U.S.A. (1976)
Pages: 234
ISBN: 0-87933-145-3
               
Electromagnetic Radiations emanating from various communication systems and devices like Radio and TV broadcasting, satellite communication, cell phones, microwave ovens and electrical and electronic appliances have now become an unavoidable area of our life. Microwaves constitute a significant part of electromagnetic radiations and contribute to “electro-pollution” as research indicates that microwaves affect living organisms. The book ‘Biological Effects of Microwaves’ by S. Baranski and P. Czerski presents the detailed research work done in this field and is one of the earliest books on the subject.  It will prove helpful for the biologists, physicians, physicists as well as budding and practising electronic engineers.

The content of the book is organized in seven chapters.

Chapter number one is the ‘introduction’ with the subject. At the beginning of this chapter the authors make our concepts clear about the important terms like microwave radiation, ionizing radiation, non ionizing radiation and radioprotection. Before dealing with the microwaves we must know about the electromagnetic radiation spectrum. There are figures, illustrations and tables describing the electromagnetic radiation spectrum, the wavelengths (cm), energy (eV) of different waves like radiofrequencies, microwaves, visible light, UltraViolet Rays, X rays and Gamma rays and explaining some examples of typical uses of equipment generating radio-frequency and microwave radiation.  It explains the uses of different ranges of frequencies, their respective applications, their occupational exposure and some examples of potential exposure i.e. general population hazards. This chapter also explains the microwave transmitter valves such as magnetron, klystron – Reflex klystron and multi cavity klystron and travelling wave tube briefly with their schematic representations.

The second chapter is about the ‘Physical Characteristics of Microwaves’. This chapter is designed in such a fashion that the reader who wants to enter in this field but have forgotten some of the basic concepts of physics related to the microwaves. This chapter is important and helpful to grasp the further concepts. It includes the basic phenomenon of formation of electromagnetic wave, set of parameters that characterize the electromagnetic waves such as frequency, velocity, wavelength, Electric and magnetic field vectors, relation between the two and the characteristic impedance. Coaxial transmission line, coaxial cable and wave guide are also explained to understand how the waves are propagated.

After getting introduced with the microwaves and going through their physical characteristics, in the third chapter we study the interaction of microwaves with the living systems. Biologists and physicians studied the interaction of microwaves with the living systems and they came to the result which had three phenomena like penetration of microwaves into a biological target and their propagation within it, secondly the primary interaction of microwaves with living matter and the secondary effects induced by the primary interaction. The three layered   semi-infinite slab model of a biological target (which is made up of skin, fat and muscle) illuminated by simple wave front is explained and may be used for solving various problems relative to the medical use of shortwave and microwave diathermy. In the later subsections primary and secondary effects of microwave interaction are studied. There are illustrations of the primary and secondary effects of microwaves on different levels of organizations ranging from molecular level to highly organized living systems.

The fourth and the most praiseworthy chapter of this book is titled ‘Biological effects of Microwaves (Experimental Data)’. It presents the collection data found in literature on experimental facts and observations on biological effects of microwaves. Various results of experiments done on different animals like mice, dog, rats, guinea pigs and cat are illustrated. Effects of microwaves on nervous system, cardiovascular effects, effects on endocrine and metabolic effects, effects on genital system, foetal development, chromosomal effects, possible genetic effects and cellular effects, effects on internal organs like abdominal cavity, chest and digestive track, effects on blood and the blood forming system, cataractogenesis are presented with experimental details. In the last section of the chapter some comments on experimental studies on the interaction of microwaves with living systems are done which are very useful while doing such experiments.

Chapter Five is about the ‘health status of personnel occupationally exposed to microwaves and the symptoms of microwave overexposure’. In this chapter the outcome experiments and conclusions of literature survey of various authors are given. At the end of the chapter the main points which are the outcome of all the survey of the literature are collected.

Microwaves are the boon for the mankind and improve our quality of  life in so many ways and it is prudent to be aware of and adopt safety standards to protect ourselves as well as the environment form the adverse effects of microwaves. Chapter Six is about the ‘Safe exposure limits and prevention of health hazards’ with analysis on the safe exposure limits of microwaves. The basic principles which may be used while determining the safe exposure limits are elucidated. At the end of the chapter prevention health hazards are given which are very much important while dealing with the microwaves.

The last chapter of the book summarises the work presented in the previous chapters and the important developments in the field till the writing of this book. The authors suggest integrated co-ordinated interdisciplinary efforts of biologists, physicians, physicists and electronic engineers. The authors have done extensive literature survey for this book and cite more than 600 references which may prove helpful for the reader for further studies in this subject. Though not recent, this book is an important reference work in its area and will prove useful for those who are doing research in this field.  

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