Showing posts with label cell. Show all posts
Showing posts with label cell. Show all posts

Tuesday, January 15, 2013

ELECTROMAGNETIC INTERFERENCE AND COMPATIBILITY (EMI / EMC) Reference Literature Survey - Book Review : BIOLOGICAL EFFECTS OF ELECTROMAGNETIC RADIATION by JOHN M OSEPCHUK (Ed)

ELECTROMAGNETIC INTERFERENCE AND COMPATIBILITY (EMI / EMC)
Reference Literature Survey - Part 2
Book Review : BIOLOGICAL EFFECTS OF ELECTROMAGNETIC RADIATION BY JOHN M OSEPCHUK (Ed)

I have been invited to deliver a lecture on Electro Magnetic Interference and Electro Magnetic Compatibility abbreviated as EMI / EMC. I have deciced to speak on the topic of Electromagnetic Pollution (or Electropollution).

This gives me a chance to brush up my rusty knowledge and let me begin by going through a few book reviews I had written earlier when I used to regularly teach this subject at the Post Graduate Level and conduct specialized training on EMI / EMC too during my faculty days at DIAT Deemed University located in the hills of Girinagar near Pune

So, Dear Reader, in case you are interested in this topic of Electromagnetic Pollution and its manifestations, do read on:


This is Part 2 in this series. 
The link to Part 1 is given below:
Part 1 - Book Review : Biological Effects of Microwaves by S Baranski and P Czerski

Book REview : BIOLOGICAL EFFECTS OF ELECTROMAGNETIC RADIATION BY JOHN M OSEPCHUK (Ed)

Here is an edited and abridged version of a book review written by one of my bright students Shashank Kekre a few years ago:

Details of the Book

TITLE: BIOLOGICAL EFFECTS OF ELECTROMAGNETIC RADIATION 
AUTHOR:  JOHN M OSEPCHUK (Ed)
PUBLISHER: IEEE PRESS, NEW YORK 1983

Book Review

This book is a collection of scientific and technical research papers of the IEEE, collected by efforts of Committee of Man and Radiation (COMAR) and is very useful for the study of Biological Effects of Electromagnetic Radiation. 

The book helps to understand the bottom-line results and also some of the reports which have greatly influenced this field of research and its practical relevance. 

The papers are presented in seven separate parts with associated references. 

The book also focuses about measures like Specific Absorption Rates (SAR), exposure on people, susceptibility standards for electronic devices to be implanted into people and beneficial medical applications of Electromagnetic Radiations. 

Some research papers also show the tests and experiments done on different animals (mammals) to demonstrate the hazards effects, and uses of electromagnetic radiations.

The book comprises of seven parts. 

Every part is compiled by various editors to cover the broad aspects of the topic by collecting different technical papers. 

A brief review on various topics is covered on subsequent paragraphs.

The first part deals with relationship between the properties of the exposure fields and the absorbed energy (rate of energy absorption) or fields in the exposed tissues. HP Schwan and GM Piersol brought out with their review to evaluate the biophysical mechanisms by which electromagnetic radiation is absorbed in tissue, and its medical applications. 

The next paper reveals the effects of temperature distribution over tissues when exposed to different kinds of radiation sources. EL Hunt, RD Phillips, DM Fleming, RD Castro have demonstrated a dosimetry system which measures the heat generated by “carcass” (dead and burnt body of an animal) thereby measuring electromagnetic wave exposure. 

The next paper states the heating patterns of cranial (skull) structure in microwave pattern. There are several problems associated with the electromagnetic wave propagation effects in living organisms. The low frequencies also now known for harmful effects due to long time exposure such as behavioral changes, burns, cataracts, etc in animal tissues. 

Further going ahead, the next paper by Habib Massoudi, Carl H Durney, and Curtis C Johnson shows the calculations of the power absorbed by an ellipsoidal model of man are given for six different orientations of the ellipsoid with respect to the incident plane wave field vectors. The results show that the induced fields and the absorbed power in the ellipsoid are strong functions of frequency, size, and orientation with respect to the incident field vectors. However, the syndicates of this paper have determined a formula that is an approximate numerical method of curve fitting to find the average specific absorption rate (SAR) over a broad frequency range. Now that we know that mammals are largely affected by microwaves, there was a requirement of measurement of these exposures, the paper by Ronald R Bowman suggests a thermistor probe and a very high resistance plastic leads to measure the RF frequency exposure. 

The last paper of this part by Om P Gandhi states electromagnetic dose for different parts of man and animals at various incident frequencies with the change in orientations of body. A typical sketch of human body is shown to illustrate the distribution of power deposition for an average specific absorption rate.

The second part brings about the various approaches on the biophysical interactions of the RF fields. 

The first paper by W Ross Adey illustrates that the nervous exhibits a rhythmic electrical activities, a set of electrical signals when we do different daily activity, even in different moods. The Electroencephalogram (EEG) measures such kind of electrical signals. Thus, brain cells also sense field potentials, which bring changes in the behavior. 

The next paper by SA Moskalenko, MF Miglei, PI Khaoshi, EP Pokatilov and ES Kiselyova states that a biological system is considered as a macroscopic model consisting of separate units which oscillate with different frequencies due to the interaction among themselves and form a set of electric dipole oscillators. There is an individual finite group of modes among these units they are called active phonons. Now if the energy is supplied to these phonons, change in frequency is observed, this is probably responsible for growth control of tissues or enzyme activities and even leads cancer. 

In next paper, Robert H Cole has presented a progressing report paper on mathematical interpretation of dielectric theory for the changes in DNA solution. The DNA structure is also represented by Watson Crick Helix. 

The subsequent paper show that change in energy of the biomolecules leads to the change in the enzyme activities and the analogy of the biophysical and biochemical processes in neuroscience with the electrochemical reactions.

The third part focuses on the thorough study of effects of the Radio Fields on the central nervous system and behavior. In the first paper by Chung Kwang Chou and Arthur William Guy, they have tried to find out the part of skull which determines the RF frequency, whether it is affected by the polarization of electric field, and the change in auditory response by using guinea pigs and cats and thus finding the analogy in the human body. The next paper brings about the threshold of the sensatiation to microwaves in rats. The paper by James C Lin, Aruthur W Guy and Lynn R Caldwell shows the operant responses of the rat carcasses (Skull) at various radiation strengths. The subsequent papers bring out the changes in behavior, dosimetry and stimuli in auditory responses on exposure to microwave.

The fourth part deals with the study on effects of microwave exposure which leads to temperature rise and causing pathology changes in animal body. 

The first paper shows the experiments on rats, rabbits and dogs on exposure to microwave thermal effects followed by cooling and the effects on eyes and testis thus, concluding the effects of the same on human body. 

The subsequent papers show the study of effects on endocrine, thyroid, pituitary changes due to exposure of microwaves of different energy and different exposure duration. The occurrence of vasodilation responses at various temperatures on exposure to microwaves is of significant emphasis in skin areas. The thermoregulatory responses on exposure to microwave post infrared exposure produce no changes in behavior. The immunity towards microwave exposure of 2450 MHz radiation for various duration are achieved by the body by lymphoid cells. Effects of microwave exposure on rabbits eye at frequencies of 2.45 to 10 GHz leads to opacity (cataract). 

A very significant study paper by Charles I Barron and Albert A Baraff shows how microwave exposures of radar effects heart, kidneys, liver, gastrointestinal and hemoarrhagic changes in respiratory system in animals and human body. 

Another paper by Charlotte Silverman reviews a study on Tri-services personnel occupationally exposed to radars causing nervous and behavioral effects, congenital anomalies, cancer etc. 

The last paper of this part by SM Michaelson shows the study of hazards associated with the development, association, operation and maintenance of radars and other radio-frequency emitting equipment on various body organs, tissues, and enzyme system on various power levels.

The fifth part reflects exposure, emission, susceptibility and medicine in diathermy, hyperthermia and diagnostic techniques on microwaves. 

The first paper illustrates the effect of deep tissue heating, and its applications. 

The next paper by JG Short and PF Turner states application of hyperthermic treatments as a choice of treatments or combination of other treatments on tumors based on their locations. 

The subsequent papers emphasize more on application of microwave radiations as a method of imaging techniques of kidneys, thermography as a means of detecting breast cancer by change in temperature of body tissues emitting thermal radiations, microwave applications in measuring neurochemical parameters, use of microwaves in thawing (upbringing to unfrozen state).

The sixth part is published with the articles covering on safety standards, the history and present state of potential hazards and microwave safety standards. The subsequent papers also put an emphasis on Biological effects and Dosimetric data for development of radio frequency safety. The data based on various RF emissions through equipment and places is also covered in the article.

The seventh part of the book covers the hazards of cardiac pacemakers due to electromagnetic interference and emission of radio frequency radiation. Other articles cover electromagnetic interference of pacemakers in dental environment by using pulse generator of various manufacturing companies.

This volume clearly brings out with various case studies, experiments, applications and illustrations on the Biological effects of Electromagnetic Radiations. 

The facts and figures help the reader to understand the functions of various systems designed and published in the articles in a simple way. 

However, the reader needs to have the requisite proficiency in electrical engineering and electromagnetic theory, mathematics, science and instrumentation and be conversant with relevant terminologies in order to better understand the effects of microwave and EM radiations on human beings and animals. 

Though published almost 30 years ago, this volume is a useful milestone reference book for those who want to delve into this fascination area of study. 

The Editor of this volume, John M Osepchuk was a consulting scientist at Raytheon Company Lexington, Massachusetts from 1950.  He received B.A. and M.A. degrees in Engineering Science and Applied Physics and a Ph.D. in Applied Physics, all from Harvard University.

Wednesday, October 26, 2011

MICROWAVE HAZARDS - BIOLOGICAL EFFECTS


Biological Effects of Microwaves - Book Review

Book Review 


Title: Biological Effects of Microwaves
Authors: S Baranski and P Czerski
Published by: Dowden, Hutchinson and Ross, Inc., Stroudsburg, Pennsylvania, 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. 

This book was published in 1976. Though not a recent publication, this book is an important reference work in its area and will prove useful for those who are doing research in this field.  

Book Review by VIKRAM KARVE

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About Vikram Karve

A creative person with a zest for life, Vikram Karve is a retired Naval Officer turned full time writer. Educated at IIT Delhi, ITBHU Varanasi, The Lawrence School Lovedale and Bishops School Pune, Vikram has published two books: COCKTAIL a collection of fiction short stories about relationships (2011) and APPETITE FOR A STROLL a book of Foodie Adventures (2008) and he is currently working on his novel. An avid blogger, he has written a number of fiction short stories and creative non-fiction articles in magazines and journals for many years before the advent of blogging. Vikram has taught at a University as a Professor for almost 14 years and now teaches as a visiting faculty and devotes most of his time to creative writing. Vikram lives in Pune India with his family and muse - his pet dog Sherry with whom he takes long walks thinking creative thoughts. 

Vikram Karve Academic and Creative Writing Journal: http://karvediat.blogspot.com
Professional Profile Vikram Karve: http://www.linkedin.com/in/karve
Vikram Karve Facebook Page:  https://www.facebook.com/vikramkarve
Vikram Karve Creative Writing Blog: http://vikramkarve.sulekha.com/blog/posts.htm
Email: vikramkarve@sify.com        

© vikram karve., all rights reserved.

© vikram karve., all rights reserved.

Monday, September 29, 2008

Cognitive Radio - The Future of Software Defined Radio

COGNITIVE RADIO

[Here is an article on Cognitive Radio compiled by my students Shijesh, Sibil, Shyju and John by browsing the internet, books and journals]


The Radio Spectrum – that segment of the electromagnetic continuum comprising the radio-frequency range – accommodates myriad communications devices today.

As the Radio Spectrum gets is gets more and more crowded and available frequencies become scarce the evolution of Cognitive Radio may be able to optimally manage the available spectrum.

The use of radio frequency bands has been regulated in most countries through the process of spectrum allocation in which the use of a particular frequency band is restricted to the license holders of the band. Within this framework, spectrum has often been viewed as a scarce resource in high demand. However, various studies carried out have suggested that most licensed spectrums are often under-utilized with large spectral holes at different places at different times.

Cognitive Radio (CR) systems have been proposed as a possible solution to the spectrum crisis. The idea is to detect times when a specific licensed band is not used at a particular place and use that band for transmission without causing any significant interference to the transmissions of the license holder. Built on the foundation of the Software Defined Radio (SDR), Cognitive Radios will learn and autonomously perform “cognitive” functions as a form of intelligence that comes from their ability to be defined and upgraded using software.

To examine the concept of cognitive radio consider the example.

Let’s say you walk into an empty café called Spectrum. Since all of the tables are available, you position yourself at the best one and settle down for a meal. [Let’s assume all tables have four seats and you occupy one seat].

A few minutes later, another person comes in and sits on a seat at another vacant table.

Soon, if all the tables are full [but there are a few vacant seats on some tables], a new patron must negotiate with someone already at a table to be allowed to share the table. [Maybe she may request you to let her occupy the vacant chair at your table, and you may agree].

This process of negotiation is the concept behind a technology called Cognitive Radio, a way to share and optimally utilize unused spectrum. Cognitive Radio is sometimes called Smart Radio because it senses its environment and reacts to it.

The present paucity of radio spectrum is primarily due to the cost and performance limits of legacy hardware established during the past century. Traditionally, radios were hardwired to operate at a particular power and frequency, and once a station was assigned a frequency, no other station could use it. Over the years, as engineers built radios in cheaper and smaller packages, it became possible to build intelligence into them, making the idea of sharing frequencies possible.

Engineers are now working to bring flexible operating intelligence to future radios, cell phones and other wireless communications devices. During the coming decade, cognitive radio technology should enable nearly any wireless system to locate and link to any locally available unused radio spectrum to best serve the consumer. Employing adaptive software, these smart devices could reconfigure their communications functions to meet the demands of the transmission network or the user.

Cognitive Radio will intelligently know, by sensing, adapting and learning, what to do based on prior experiential knowledge, by building an internal database that defines how to best operate in different places and at specific times of day.

As Cognitive Radios send and receive signals, they will nimbly leap and bound in and out of free bands as required, avoiding those that are already in use. This lightning-fast channel jumping will permit cognitive radio systems to transmit voice and data streams at reasonable speeds.

This efficient use of existing Radio Frequency resources will alleviate spectrum-availability traffic jams and wireless communications may become far more dependable, convenient and, perhaps, considerably economical than it is today. Indeed, if Cognitive Radio technology progresses as its developers hope the airwaves will never be the same again.