BARRY RAMACHANDRA RAO (21 November 1922 - 24 September 2005)

Biog. Mem. Fell. INSA, N. Delhi 30 181-196 (2006)

BARRY RAMACHANDRA RAO (1922-2005) Elected Fellow 1969

FAMILY BACKGROUND AND EARLY EDUCATION ARRY RAMACHANDRA RAO was born on 21 November 1922, to his father BB Satyanarayana and mother, Subhadramma at Yellamanchili in Visakhapatnam District of Andhra Pradesh (which was then part of the Madras Presidency). His father was employed at the Port Trust. He had his high-school education upto the Intermediate years at the AVN College High School in Visakhapatnam. He then joined the Andhra University and graduated in 1944 with a B.Sc. (Honours) degree in Physics, securing the first rank in the University. Following this, he qualified for the M.Sc. degree in Physics by research in 1945 from the same University. Subsequently, he registered for the doctorate programme in Physics in the field of ultrasonics, under Professor S Bhagavantam, and submitted his thesis titled "Diffraction of Light by High Frequency Ultrasonic Waves", for which he was awarded the degree of D.Sc. in 1949 by the Andhra University. For his academic brilliance, he was awarded 'Sreepathi' and 'Metcalfe' Medals by the University.

PROFESSIONAL CAREER AND SCIENTIFIC CONTRIBUTIONS After completing his doctoral studies, Dr. Rao worked as Senior Scientist in a CSIR Scheme at the Geology Department of the Andhra University during the years 1948- 50. He visited Australia (1951-52) as a Commonwealth Senior Research Fellow, to work with the renowned Ionosphere scientist Professor DF Martyn, before returning to India to join the faculty of the Physics Department of Andhra University as a Reader in Physics in 1953. Here he initiated research work in the field of Ionosphere and established a strong research group in this area. Along with his students, he made many important contributions to the area of Ionospheric drifts, Spread F and Sporadic E. During 1956, he spent 6 months as a Visiting Fellow under India Wheat Loan Exchange Programme in USA. He was promoted as a Professor of Physics in 1958, a position in which he continued till 1976. In that year, he was appointed as Vice- Chairman of the University Grants Commission, New Delhi, a position which he held till his retirement in 1982. Biographical Memoirs RESEARCH CONTRIBUTIONS Dr. Rao had a brilliant and illustrious academic career, carrying out pioneering research work in ultrasonics. He guided research students not only in ultrasonics, but also in the areas of ionospheric physics (now called Space Science) and electronics. He supervised the research work towards doctoral degree for nearly 40 students. He initiated and motivated research students to build their own apparatus for their research work, thereby promoting an attitude of self-reliance amongst them. As an outcome of this approach to research, a large number of instruments for ionospheric and atmospheric research were developed in his laboratory. A striking example is the development of a high power Doppler Meteor Radar to detect, measure and track individual meteor trails in the atmosphere during day and night. Many of the instruments developed in his laboratory are now being put to effective use in several industries.

TEACHING CAREER He was considered a teacher par excellence. The students never missed his lectures which were always so very interesting. The students were also greatly impressed with his analytical ability and scientific integrity. He took classes in Solid State Physics, Nuclear Physics, Electricity and Magnetism, Electronics and Crystallography, both at the undergraduate and postgraduate levels, and taught courses in the History and Philosophy of Sciences. He developed instructional materials, teaching aids as well as demonstration-cum-laboratory apparatus for undergraduate colleges. As Professor of Physics in the Andhra University, Dr. Rao directed summer institutes and training programmes for improving the functional capacities of school and college teachers. He also directed a project on 'Physics Apparatus Workshop', to popularize the concept of earning while learning. Under this project, a large number of scientific apparatus were developed and designed by postgraduate and doctoral students, with the know-how transferred to some industries. He also initiated a number of innovative educational reforms in terms of modern curriculum development, examination reforms like the semester system, internal assessment and new methods of teaching. He also took keen interest in the application of Science and Technology for the development of the country. He worked for the development of small-scale industries, Science Education, adult education programmes and International cooperation in science and technology, particularly among the developing countries. He worked steadfastly for the popularization of Science and Rural Development. Barry Ramachandra Rao SCIENTIFIC CONTRIBUTIONS Ramachandra Rao's research contributions cover a wide range of topics in the fields of ultrasonics, ionospheric physics and electronics. His research career began initially with his doctoral studies involving original contributions in the field of ultrasonics, under the mentorship of Professor S. Bhagavantam. His early contribution in this field was the development of a theory of diffraction of light by high frequency ultrasonic waves. He also made the first time observation of asymmetry in diffraction by superposed ultrasonic waves, and developed a generalised theory to explain the phenomenon. Over the years, his contributions have included developing new methods of determining ultrasonic wave propagation characteristics, as well as determining physical properties of organic and inorganic substances for ultrasonic waves. References to his contributions in ultrasonics can be found in most standard books on ultrasonics. He built a flourishing school of Radiophysics at Andhra University, and carried out extensive research work in many aspects of ionospheric physics. His work on ionospheric drifts has been recopsed as outstanding. His forays into the field of electronics include sipficant contributions to the theory of alloy junction and drift transistors. He has extended the existing theories to cover a wider range of frequencies by taking into consideration recombination effects in the emitter junction and other parameters which are usually neglected in simple theories. Some of Dr. Rao's important research contributions are: Studies on Diffraction of light upto 400 Mc/s. Theory of diffraction of light by superposed waves. New methods of studying ultrasonic velocity, absorption, etc in liquids. Characteristics of horizontal ionospheric drifts over a sun-spot cycle. New and simple methods of measuring some of the physical parameters of diffusion and drift transistors. Theoretical studies of the performance of diffusion and drift transistors. Professor Ramachandra Rao supervised and guided over 40 candidates who have obtained doctorate degrees. The details are as under: 1957 SRI RAMA RAO N Studies on Ionospheric Winds SATYANARAYANA MURTY D Studies on Radio Fading Horizo Ionospheric Drifts Biographical Memoirs SUBBA RAO K Ultrasonic Studies in Solid and Liquid Media by New Methods SATYANARAYANA MURTY J Diffraction of Light by Ultrasonic Waves 1959 BHAGIRATHA RAO E Drifts and Traveling Disturbances in Ionosphere - RAMA RAO HS Ultrasonic Studies in Liquid Media 1960 RAGHAVA RAO Studies on Ionospheric Drift in E Region GOPALA RAO MSV Studies on Spread F at Waltair 1961 PADMINI PRKL Ultrasonic studies in Liquid State RAMANA KVV Studies on Ionospheric Absorption and Horizontal Drifts 1962 SESHAGIRI RAO MG Studies on Ultrasonic Properties of Liquid Solutions ABHIRAMA REDDY C Studies on Polarisation of Downcoming Radio Waves at Waltair KRISHNA MURTY BV Studies on Spread F in the Ionosphere over Waltair BALARAMA RAO P Studies on Drift and Anisotropy of Ionospheric Irregularities RAMANA MURTHY YV Ionospheric Absorption of Short Radiowaves SANYASI RAO A Studies on Horizontal Drift in Ionosphere MUKUNDA RAO M Studies on Sporadic-E and F2 Layers on the Ionosphere SIVARAM BM Studies on Ionospheric Drifts KRISHNAMURTHY C Ultrasonic Absorption in Solutions for Cuprous Lanthanum and Zinc Acetates SITARAMASWAMY P Ultrasonic Studies in Liquid Mixtures VEERAYYA T Ultrasonic Studies in Molten Electrolytes NARAYANA RAO GL Studies on Horizontal Drift and Winter Anomalous Absorption in the Ionosphere JAGATKUMAR V Studies on the phenomenon of Spread F in Ionosphere PS KESAVA RAO Studies on horizontal drifts and fading of radiowaves in the ionosphere at WaItair A SUGUNA MOHANA RAO Studies on short wave ionospheric absorption GR MOHANA RAO GR Physical parameters of alloy junction transisto Barry Ramachandra Rao 187 1969 C JOGULU C Studies on Horizontal drifts and anixotrophy parameters of irregularities in ionosphere - IQBAL AHMAD Studies on Cosmic noise absorption 1970 C RAGHAVA REDDY Studies on ionospheric movement at Waltair using phase path techniques SP MANOHAR RAO Studies on Sporadic-E J SRIRAMA MURTHY Studies of ultrasonic absorption & relaxation in liquid salts 1971 PT SANYASI RAJU Studies on Spread-F irregularities and F2 region anomaly - J HANUMANT SASTRY Studies on drift and anisotrophy of ionospheric irregularities at Waltair 1975 B SURYANARAYANA MURTHY Studies on small scale irregularities and travelling wave disturbance in ionosphere - TSN SOMAYAJI Spaced receiver methods for ionospheric salts 1981 S PATANJALI SASTRY Studies on the nature of ionospheric motions RAMA CHANDRASEKHAR Studies on some aspects of absorption of radio waves in the ionosphere 1982 JVM NAIDU Low frequency propagation studies of the lower ionosphere

RAMACHANDRA RAO AS EDITOR He was co-editor for a book titled Physics of the Solid State: Commemoration Volume for Professor S Bhagavantam, published in 1969 by the Academic Press, New York. As a member of the Editorial Board of the National Council of Educational Research and Training, New Delhi, he edited a number of books in physics for undergraduate students. He also edited a number of books on Physics, written in his native regional language of Telugu, for undergraduate and postgraduate students.

RAO AS AN ADMINISTRATOR As Vice-Chairman of the University Grants Commission from 1976 to 1982, Dr. Rao introduced several innovative schemes to improve the quality of education. He was instrumental in initiating new courses in computer sciences; strengthened centres of excellence, especially in science and technology; generated a programme of career awards for young university scientists, expanded computer facilities in universities and initiated collaborative research in nuclear sciences, radio-astron and space-physics at several national centres in the country. Biographical Memoirs Dr. Rao was actively associated with several organizations for the growth and development of Physical Science and served the Indian Science Congress Association as General Secretary from 1977 to 1980 and as its General President from 1982 to 1983. He was instrumental in founding three scientific societies: Indian Physical Association, Acoustical Society of India, and the Asian Physical Society. Prof. Rao was a member and leader of various scientific delegations to many countries.

AS A HUMAN BEING As a researcher, his enthusiasm for science and as a mentor for his students was so great that he was reported to visit the laboratory even at 2 AM to help the students. According to Dr. Sanyasi Rao, one of his students, he was so full of compassion that he used to pay the school fees of some of the very poor students.

HONOURS, AWARDS AND DISTINCTIONS Ramachandra Rao has been honoured with many fellowships and awards during his career. Some prominent ones are: Sri Shanti Swarup Bhatnagar Award, for outstanding contributions in Physical Sciences, 1965 "Distinguished Service Award", Indian Science Congress Association, 1968 D.Sc., Honoris Causa, for outstanding contribution to Physics, Andhra University, 1970

MEMBERSHIP IN PROFESSIONAL SOCIETIES Fellow, Andhra Pradesh Academy of Sciences, 1963 Fellow of the Indian National Science Academy, 1969 Fellow of the Academy of Sciences, Bangalore, 1974 Fellow, National Academy of Sciences, Allahabad, 1979 Elected Fellow of the Physical Society, London Member, British Institute of Electronic and Radio Engineers Senior Member, Institute of Radio Engineers (USA) Dr. Rao held leadership positions in several professional organisations, some of which are listed below: Member, Indian National Science Academy Council, 1972-74 President, Andhra Academy of Sciences, 1975-76 Chairman, Indian National Committee for IUPAP, 1975-77 Treasurer, Indian National Science Academy, 1977-80 Barry Ramachandra Rao a Chairman, Indian National Committee for COSTED, 1980-88 a President, Acoustical Society of India, 1980-82 a President, National Academy of Sciences, Allahabad, 1981-82 a President, Indian Science Congress Association, Calcutta, 1982-83 a Vice- President, Asian Physical Society, 1980-83 a Acting-President, Asian Physical Society, 1984-85

SUMMARY OF SCIENTIFIC WORK

Research Areas: Ultrasonics, Space Physics, Electronics Has published over 300 published papers in scientific Journals in India and abroad. Ultrasonics Dr. Rao developed new techniques to push the existing frequency limit of 50 Mc/s upto 300 Mc/s for generation of ultrasonic waves. He observed new and unusual features of diffraction and developed theoretical models for interpreting these observations, as well as a simple theory of diffraction of light at very high frequencies. He was the first to observe a new phenomenon of asymmetry in diffraction by superposed ultrasonic waves at normal incidence, and he developed a generalised theory to explain this phenomenon. He developed several new precision methods for measuring ultrasonic velocity and its variation with temperature in liquids, variation of ultrasonic absorption in liquids with temperature and elastic constants in solids. He made extensive studies of: a) the relationship between ultrasonic velocities and apparent molar compressibility in aqueous electrolytic solutions, hydration numbers and their variation with temperature; b) ultrasonic velocities in solutions of organic solids in organic solvents; c) molar sound velocities in several elements; d) relationship between ultrasonic velocity and latent heat of vapourisation; e) relationship between temperature variation of ultrasonic velocity, molecular weight and boiling point. Ionospheric Physics Dr. Rao was the first in the country to make ionospheric wind measurements at Waltair, Andhra Pradesh, by the spaced receiver method. As an outcome of this study, he established for the first time that the drift pattern at low latitude stations is entirely different from that at high latitude stations. Biographical Memoirs Electronics Dr. Rao developed new and simple methods of measuring some of the physical parameters of diffusion and drift transistors and carried out theoretical studies of the performance of diffusion and drift transistors. Extra-curricular Activities During the 'Quit India" movement in the early 1940s, he took active part in the Freedom Movement to end Britain's colonial rule in India. He was an active member of the Congress Party and a staunch supporter of Indira Gandhi. He became Chairman of the AICC(1) Cell on Science, Technology and Environment, and established PCC(1) cells in all the States of the country, and organized many seminars on, Energy, Rural Technology, Water Management and Technology Missions. One of these cells, in Andhra, organised a major National Seminar on "Science in India since Independence". He was the first eminent scientist to be nominated as a Member of the Rajya Sabha. He represented the State of Andhra Pradesh in the Rajya Sabha, from April, 1982 to April, 1988. He launched a number of social-welfare societies and carried out programmes dedicated to the welfare of the downtrodden and weaker sections of society. He played a leadership role in 1) National Association of Fishermen, 2) Association for Continuing Education, 3) Centre for National Integrity and Development, and 4) Visakha Rural Aid Trust. He worked assiduously for the welfare of the fishermen community and served as the Chairman of the National Association of Fishermen, thereby establishing his credentials as the acknowledged leader of 30 million members of the fishermen community, initiating programmes like socio-economic survey, adult education, integrated development of fishermen's villages. He also served as Chairman of the Society for the Welfare of Scheduled Castes and Scheduled Tribes. Professor Ramachandra Rao passed away on 24th September 2005 at the age of 83. In the passing away of Prof. Rao, the country has lost an outstanding social worker and the scientific community an eminent scientist.

ACKNOWLEDGEMENT Thanks are due to Dr. Sanyasi Rao for information regarding Dr. Rao's family background and early education. E SUBRAMANIAN Emeritus Professor of Bio

E-mail address: Bar y Ramachandra Rao BIBLIOGRAPHY Elastic constants of quartz Curr Sci 14 17. Elastic constants of granets Proc Ind Aca Sci 22 194. (With BHAGAVANTAM S) Determination of elastic constants of isotropic media a new method Ibid 23 294. (With BHAGAVANTAM S) Elastic constants of isotropic media Nature 157 624. (With BHAGAVANTAM S) Diffraction of light by ultrasonic waves of very high frequencies Nature 158 484. Very high frequency sound velocities in acetone water mixtures Proc Ind Aca Sci 25 190. (With BHAGAVANTAM S) Diffraction of light by highfrequency ultrasonic waves Nature 159 267. (With BHAGAVANTAM S) Hiedemann patterns at very high frequencies Ibid 159 742. (With BHAGAVANTAM S) Diffraction of light by very high frequency ultrasonic waves Ibid 161 927. (With BHAGAVANTAM S) Diffraction of light at very high frequency ultrasonic waves effect of tilting the wave front Proc Ind Aca Sci 28 54. (With BHAGAVANTAM S) Elastic constants of alum determined by a new method Nature 162 818. Diffraction of light by superposed ultrasonic waves Proc Ind Aca Sci 29 16. A new type of scale of two units Jou Sci Ind Res 9B 185. New ultrasonic method for determining elastic constants Current Sci 19 148. A new method for measuring velocities of ultrasonic waves in liquids Nature 166 742. Ultrasonic velocities in liquid by a new method Proc Ind Acad Sci 34 24. (With BHAGIRATHA RAO E) Investigation of traveling disturbances in the ionosphere by continuous wave radio Nature 172 819. (With SUBBA RAO K) A new precision method for measuring ultrasonic velocities in liquids Ibid 17ll077. (With RAO BCN) A continuous wave radio method of studying the variation of critical frequency of the e region of the ionosphere Proc Mixed Commn Brussels 103. (With SRIRAM M and SATYANARAYANA D) A note on ionospheric wind measurements at Waltair Ibid 158. (With NVGS) Periodic fading in medium wave radio signals Current Sci 23 287 (With BHAGIRATHA RAO E) A new continuous wave method of study of traveling disturbances in ionosphere Jou Sci Ind Res 13 A 462.

(With SUBBA RAO K) Investigation- of ultrasonic velocities in liquids by a new method Ind Acad Sci 39A 132. (With PVR) A modified method for exciting shear modes in isotropic media Nature 174 83 192 Biographical Memoirs 1955 (With SRIRAM M) Slow periodic fading in medium wave radio signals Nature 175 459. (With PVR) Determination of shear waves velocities in isotropic solids by a modified wedge method Acoustics 5 217. - (With SRIRAM M and SATYANARAYANA MURTHY D) Effect of solar eclipse of 20th June 1955 on long distance short wave transmission Curr Sci 24 408. 1956 (With SRIRAM M and SATYANARAYANA MURTHY D) Investigation of winds in the ionosphere by the spaced receiver method Jou Sci Ind Res 15A 75. (With SATYANARAYANA D) A simple method of studying hoizontal drifts in the ionosphere by using continuous wave radio Nature 177 1222. (With RAMANA KV) Simultaneous signal strength measurements on continuous and pulsed radio wave transmission reflected from the ionosphere Curr Sci 25 284. (With SATYANARAYANA MURTHY J) Diffraction of light by ultrasonic waves at 300 Mc/s Nature 178 160. (With MRR) A new diffraction method for measuring ultrasonic velocities in liquids Current Sci 25 390. 1957 (With SRIRAM M) Investigations of horizontal drifts in the E region of the ionosphere in relation to random fading of radio waves IRS Nut Con Toronto. (With BHAGIRATHA RAO E) Investigation of ionospheric drifts in the F region over Waltair Pand Ind Ocean Sci Congress Madagascar. (With SUBBA RAO K) A new electronic method for measuring ultrasonic velocities in liquids Jou Sci Ind Res 16B 483. (With SUBBA RAO K) A simple method of determining ultrasonic velocities in rocks Nature 180 978. 1958 (With SATYANARAYANA MURTHY D) Diurnal variation of horizontal drifts in the F2 region of the ionosphere Bul National Ins Sci Ind July. (With SRIRAM M) Investigation of magnetoionic fading in oblique incidence medium wave transmission Jou A tm Terr Phy 12 232. (With BHAGIRATHA RAO E) Horizontal ionospheric drifts in the F2 region Equitorial latitude Nature 181 1612. (With REDDY CA and SRIRAM M) Magneto-ionic fading in pulsed radio waves reflected at vertical incidence from the ionosphere Jou Brit I R E 18 669. (With SATYANARAYANA MURTHY D) A simple CW method of studying ionospheric drifts Jou Sci Ind Res 17A 62. (With BHAGIRATHA RAO E) Effect of enhanced solar activity on the F2 region drift in Waltair Ibid 17A 62. (With RAMANA W) Diurnal variation of absorption on 5 6 M/s at Waltair during IGY lbid 17A 56. (With SUBBA RAO K) A variable frequency interferometer for measurement of ul velocities in liquids Acoustica 8 63. Bar y Rarnachandra Rao 193 1958 (With SATYANARAYANA MURTHY J) Diffraction of light by weak ultrasonic fields Zeit Phy 152. (With SUBBA RAO K) Ultrasonic studies on some inaqueous solutions of electrolytes Jou Sci Ind Res 17B 444. (With HSR) A new method of studying variation of ultrasonic absorption in liquids Nafure 182 1794. 1959 (With BHAGIRATHA RAO E) Study of horizontal drifts in the F region of ionosphere at Waltair Jou A tm Terr Phy 14 94. (With BHAGIRATHA RAO E and RAMANA MURTHY W) Effect of magnetic activity on F2 drifts at Waltair Nature 182 667. (With SUBBA RAO K) Investigation of ultrasonic velocities in organic solutions Proc Phy Soc 73 239. (With SUBBA RAO K) Study of ultrasonic velocity in organic solutions Curr Sci 28 108. (With SUBBA RAO K) Ultrasonic studies in some organic liquid mixtures Ibid 29 89. (With KRISHNAMURTHY C) Investigation of accumulation and persistence time of ultrasonic stristion grating of starch suspension in liquids Jou Nuovo Cimento 11 212. (With SUBBA RAO K) Study of temperature variation of ultrasonic velocities in some organic liquids Ame Acou Soc 31 439. - (With MURTY JS) Diffraction of light by superposed ultrasonic waves Zeit Phy 157 189. 1960 (With RRR) Horizontal drifts in the E region at Waltair Nature 185 27. (With GOPALA RAO MSV and PANT PR) Correlation of spread F activity F region height changes Jou Atrn Terr Phy 17 345. (With GOPALA RAO MSV and PANT PR) Fading of C W Signals as a means to spread F study Curr Sci 29 304. (With PADMINI PRKL) Relation between ultrasonic velocity and latent heat of vaporization Nature 23 311. (With PADMINI PRKL and SUBBA RAO K) Study of molar sound velocity in liquids Tra Fara SOC56 1404. (With PADMINI PRKL and SUBBA RAO K) Molar sound velocity in organic acids Jou Chem Phy 33 1268. (With PADMINI PRKL) Ultrasonic velocity in some aqueous solutions of electrolytes Ind Jou Phy 12 565. (With RAO HS) Ultrasonic absorption measurements in some pure liquids Curr Sci 29 7. 1961 (With BHAGIRATHA RAO E) Diurnal variation of Fi region drift at Waltair Curr Sci 30 9. - (With RAO ASP) A new type of 3 channel electronic switch Jou Sci Ind Res 20 83. (With RAMANA KV) Variation in height of anisotropy and random drift velocity in the ionosphere Nature 190 706. (With RAO RR) A new type of ionospheric drift recorder Jou Atrn Terr Phy 21 208. Biographical Memoirs 1961 (With RAMANA KW) Investigations of ionospheric absorption on 5 6 Mc/s at Waltair Ibid 22 1. (With GOPALA RAO MSV) Nocturnal and seasonal variation of equatorial spread F Ibid 22 12. (With RAO RR) Study of horizontal drifts in the E region over Waltair Ibid 22 158. (With BHAGIRATHA RAO E) Horizontal drift in the ionosphere in relation to random fading Jou Sci Ind Res 20 301. (With RAO ASP) A transistor gated emitter follower for testing pulse receivers Ibid 20 548. (With BHAGIRATHA RAO E) Simultaneous study of drift of different levels in the ionosphere by speed receiver method Brit IR E 22 507. (With RAO HS) Ultrasonic absorption in aqueous electrolyte solutions Jou Sci Ind Res 20B 93. (With RAO HS) Ultrasonic velocities in some binary liquid mixtures of benzyl alcohol Ibid 20B 157. (With RAO HS) Ultrasonic absorption studies in binary mixture of benzyl alcohol Ibid 20B 466. (With MURTHY CK) Effect of setting of Agar Agar solutions on velocity of ultrasonic waves Ibid 20B 608. (With RAO MGS) Ultrasonic velocity studies in aqueous solutions of some electrolytes Nature 191 164. (With PADMINI PRKL) Molar sound velocity in molten hydrated salts Ibid 191 695. (With MURTY JS) Diffraction of light by very high frequency ultrasonic waves Proc Phy Soc 77 958. (With PADMINI PRKL) Study of ultrasonic velocity in liquids hdJou Phy 35 346. 1962 (With RAO ASP) A transistor circuit of impedance matching between loop and aerials and transmission lines Jou Sci Ind Res 21 B 37. (With RAO ASP) A transistorized 3 channel electric switch Ibid 21B 570. (With KW RAMANA) Lunar daily variation of horizontal drifts in the ionosphere at Waltair Jou Atm Terr Phy 24 220. (With REDDY CS) Polarisation characteristics of Es echoes at Waltair Ibid 24 401. (With KRISHNAMURTHY BV) Lunar variation of spread F Ibid 24 742. (With KRISHNAMURTHY BV) Nocturnal and seasonal variation of spread F at Waltair Ibid 25 1. (With REDDY CS) The observed polarization of high frequency radio waves at low latitude stations Ibid 25 13. (With SESHAGIRI RAO MG) Ultrasonic studies in aqueous solutions of nitrate Curr Sci 31 9. (With RAO MGS) Dispersion of ultrasonic velocity in liquids Ibid 31 177. (With PADMINI PRKL) Molar sound velocity in solutions of metal organic compounds Fara Sci 58 650. (With RAO MGS) Balanced bridge thermocouple circuit for measurement of crystal cur Jou Sci Ind Res 21B 331. Bar y Rarnachandra Rao (With RAO MGS) Ultrasonic studies in aqueous solutions of electrolytes Ind Jou Phy 1 66. (With PADMINI PRKL and RAO MGS) Study of temperature variation of ultrasonic velocity in liquids at low temperatures Proc Phy Soc (Japan) 18 875. (With MGS RAO) Ultrasonic velocity in aqueous solutions of electrolytes and hydrated numbers Ind IOU Pure and App Phy 1 10. (With KRISHNAMURTHY BV) Time of onset spread in relation to post sunset hf variation Ihid 25 209. (With RAO AS) Horizontal drift in the F region in Waltair Ibid 25 249. (With RAO PB) Seasonal and diurnal variation of the drift in the E and F regions of ionosphere P~OCInt Conf Ionosphere 363. (With KRISHNAMURTHY BV) Effect of magnetic activity and F region height changes on equatorial spread F Ibid 309. (With KRISHNAMURTHY BV) Fading characteristics of spread F echoes Jou Geo Res 68 1923. (With REDDY CA) Polarisation of radio waves in relation to random fading Ind Jou Pure and App Plzy I 252. (With RAO VVN) Transistorised phase shift oscillator Elect Engg Sept. (With RAO GLN) Worldwide study of horizontal drift and anisotropy of inospheric irregularities in the E region Jou A tm Terr Phy 25 553. (With RAO MM) The effect of electrojet on the seasonal variation of spread F Ibid 25 571. (With RAO GLN) World wide study of apparent horizontal movement of F2 region of the ionosphere Bid 25 231. (With RAO PB) Height variation of drift and anisotropy of the ionospheric irregularities Ibid 26 231. (With RAO AS) Horizontal drifts of E region at Waltair Ibid 26 399. (With RAO PB) Effect of magnetic activity on drift and anisotropy of the E and F region irregularities Ibid 26 445. (With RAO GLN) The latitude variation of height in E region drift speeds Ibid 26 628. (With KRISHNAMURTHY BV) Variation of spread F index with frequency in pre and post midnight portions at Waltair Ibid 26 783. (With RAO MM) A study of sporadic E layer over Waltair Ibid 26 831. (With RAO PSK) Fading analysis of ionospheric drift records Ibid 26 841. (With RAMANA MURTHY W) Frequency variation of ionospheric absorption at vertical incidence Ibid 26 849. (With RAMANA MURTHY W) Study of ionospheric absorption on 2Mc/s at Waltair Ibid 26 1087. (With RAO PB) Drift and anisotropy of irregularities in the lower region under magnetically active condition Curr Sci 23 11. (With RAO AS) Height gradient of horizontal drifts in the E region at Waltair ITE 10 410. Biographical Memoirs (With KRISHNAMURTHY BV) F region drift and anisotropy parameters under spread F conditions Ind Jou Pure and App Phy 2 302. (With RAO MGS) Temperature variation of acoustic velocity in aqueous solutions of electrolytes Proc Phy Soc (Japan)19 1394. (With RAO AS) A compative study of E and F2 region horizontal drifts at Waltair Ibid 3 103. (With RAO AS) Effect of magnetic activity F2 region drift at a low altitude station Ibid 3 300. (With RAO AS) Lunar daily variation of horizontal drifts in E And F2 regions Jou Atm Terr Phy 27 661. (With RAO GLN) Effect of magnetic activity on drift and anisotropy of ionospheric irregularities at Waltair and Yamagawa IJTEngg 10 537. (With VRJ) Latitude effect of variation of spread F Nature 1083. (With RAO KJM) Determination of Physical parameters of a junction transistor JlTE 12 331. (With RAO MM) Land term variation in equatorial sporadic E and Electrojet Plan Space Sci 14 529. (With RAO MGS) Ultrasonic studies in binary liquid mixtures Ind Jou Pure App Phy 3 156. (With RAO GRM) Determination of base spreading resistance and junction temperature of uniform base junction transistor Insf Electronics 21 201. (With RAO GRM) Determination of some of the physical parameters of alloy junction transistors Jou ITE 12 343. (With RAO ASM) Theoretical estimates of the variation of absorption with frequency using N-n profile Ibid 12 432. (With RAO GRM) On some physical parameters of uniform base junction trasistor Ibid 12 484. (With RAO GRM) On the variation of current amplification factor with emitter current at low injection levels Int Jou Elec 21 457. 1967- (With RAO PSK) Radio wave fading at Waltair during IGY Curr Sci 36 148. (With RAO PSK) Studies on the drift of E region at Waltair aid 36 392. (With AHMED IQBAL) Lunar semi-diurnal variation midday to F2 over Singapore and Baguio Jou ITE 13 54. (With REDDY CR) Direction of movement of F2 region pertubarations IREE 34 53.