Multi-colour universe

Guest Editors: R.K. Manchanda and B. Paul

Journal of Astrophysics and Astronomy, Vol. 23,

Nos.1/2, March/June 2002, pp. 1_172

X-ray astronomy has seen many revolutionary trends since the discovery of the first X-ray source in 1962. Starting as a part of cosmic ray research with the early experiments using rockets and balloons, it has acquired a leading place in mainstream astronomy and astrophysics. The first path breaking event took place in 1970 with the launch of the UHURU satellite. The first technological breakthrough came with the launch of the Einstein satellite in 1978, which for the first time employed the principle of focusing optics in the low energy X-ray region. The X-ray sky today is dotted with sources, which are 17 magnitudes fainter than ScoX-1, the first discovered source. A wealth of observational data has been produced on the entire ensemble of visible and invisible universe. However we are no closer to a complete understanding of the complexities of temporal and spectral properties of the large variety of X-ray sources. Due to limitations of the available technology of detecting high energy photons, the energy band above 20 keV is still poorly explored. The most recent trend in the efforts to unlock the mysteries of our universe is the `multi-wavelength' approach which can give a more complete picture of the X-ray sources and emission mechanisms.

Experimental work in X-ray astronomy at TIFR started in 1966, using balloon-borne instruments in the energy band of 20_100 keV region. Rocket-borne soft X-ray surveys (0.15_2 keV) were conducted during 1972_1982. An all sky monitor to detect transient sources and study the time variability of steady X-ray sources in the energy range 2_20 keV was fabricated and launched on board the second Indian satellite Bhaskara in 1979.

It seemed an appropriate time to hold an international symposium to take stock of the recent developments in X-ray astronomy with particular emphasis on multi-wavelength observations. The four-day symposium entitled `Multi-colour Universe' was held during September 11_14, 2001 at TIFR, Mumbai with the main aim of educating ourselves about the enormity of the discipline and the emerging priorities for coming decades. The programme consisted of invited reviews, contributed talks and poster sessions.

This special volume contains a selection of 28 papers presented at the symposium in three broad categories: the Galactic sources (black hole and neutron star X-ray binaries, CVs, SNRs and stars), the extragalactic X-ray sources (Galaxies, AGNs, quasars, X-ray background and clusters of galaxies) and new technologies and future missions.

Fracture mechanics of concrete
Guest Editor: B.K. Raghu Prasad

Sadhana, Vol. 27, No.4, August 2002, pp. 411_492

Fracture mechanics of concrete is generally considered the third phase in the evolution of concrete structures. It was Kaplan in 1961 who tried to obtain the fracture toughness of concrete. It was later observed that there was no consistent value of fracture toughness of concrete. Towards early eighties, nonlinear fracture theories were proposed. The process zone ahead of the crack tip was identified as having an important role to play in the nonlinear fracture mechanics of concrete. A little later, it led to the size effect. Various meetings subsequently discussed the developments in this field. In recent years, as high performance concrete is gaining importance, its fracture behaviour is being studied with great seriousness. High strength concrete is nearer to linear theories of fracture and is relatively more brittle. The challenge is whether one can make high strength concrete relatively more ductile by improving the cohesiveness of cracks. The next question is how to bring the size effect into codes of practice on the design of reinforced concrete structures, since large structures like dams, nuclear reactors, and very tall towers, do contain large sized members.

This special issue attempts to address the question whether it is in order to assume the same tensile strength as obtained in the laboratory for full-scale structures as well. The six articles on concrete cover work on crack formation and fracture energy, embrittlement and apparent strength, cohesive stresses, size effect and its application to compressive strength, and finally ATENA, a software for nonlinear fracture.

Modern trends in inorganic chemistry

Guest Editor: P. Banerjee

Proceedings: Chemical Sciences, Vol. 114, No.4, August 2002, pp. 231_460

This special issue of the Proceedings is based on 19 papers presented at the Ninth Symposium on "Modern trends in inorganic chemistry" (MTIC-IX) held in December 2001 at the Indian Association for the Cultivation of Science, Kolkata. The topics covered in MTIC-IX span a wide range in keeping with the current trends of research in inorganic chemistry.

Recent advances in photochemistry

Guest Editors: J. P. Mittal, Tulsi Mukherjee and A. V. Sapre

Proceedings: Chemical Sciences, Vol. 114, No.6, Dec. 2002, pp. 521_774

Photochemistry is considered a thrust area of research activity worldwide. To bring together various researchers and students working in Asian countries, Asian Photochemistry Conferences (APC) have been held since 1997 in Hong Kong and Korea. The third was held in India at Mumbai in January 2002. Due to the complementary nature of radiation and photochemistry, the biennial Trombay Symposium on radiation and photochemistry (TSRP) was jointly held with APC.

This volume is a selection of 23 articles dealing with frontline and thrust areas of research in radiation and photochemistry.

Pan ocean remote sensing conference (PORSEC)

Guest Editors: E. Desa, R. Brown, S. Shenoi and George Joseph

Proceedings: Earth and Planetary Sciences, Vol. 111, No.3, Sept. 2002, pp. 187_378

The Pan Ocean Remote Sensing Conference (PORSEC), earlier known as the Pacific Ocean Remote Sensing Conference (PORSEC), was formed in 1992 to provide a venue for international cooperation in the increasingly important area of remote sensing of the ocean. Many countries that border the southern and tropical ocean are experiencing rapid "development", the impact of which is significant on the oceans though difficult to quantify. PORSEC aims at providing a common platform for scientists to discuss innovative applications for the newly available global satellite data sets. This is expected to lead to cooperation in studying ocean-related topics as diverse as air-sea interaction, fisheries, and pollution. Through this cooperation, holders of satellite data hopefully meet and interact with holders of sea-truth data to their mutual benefit.

Since its formation, PORSEC has met in Okinawa, Melbourne, Victoria and Qingdao. The fifth meeting at Goa was held during December 2000, at which 262 participants from 31 countries attended. A substantial two-volume proceedings (900 pages) containing 197 papers was published during the conference. The present volume is a compilation of seventeen selected papers from the conference. The papers are evenly divided between applications of ocean colour, wind and ocean dynamics, and modelling with satellite sensor (mainly microwave) data. Some of the presentations are of regional interest, while others will find an audience beyond the satellite remote sensing community. These first results through their simple presentation of observations and hypotheses could well contain the seeds of breakthrough science.

The biology of Entamoeba histolytica

Guest Editor: Anuradha Lohia

Journal of Biosciences, Vol. 27, No.6, Nov. 2002, pp. 553_628

Protozoan parasites, especially the ones which cause disease, are of tremendous interest to biologists. The reason is that these `lower eukaryotes' are able to successfully encroach, occupy and not only live-off a `higher eukaryote', they also cause terrible misery to their unknowing hosts. One such human pathogen, Entamoeba histolytica forms the subject

matter of this special issue.

These unicellular organisms were referred to as `primitive eukaryotes' in text books and journals alike, since they (supposedly) lacked `typical eukaryotic subcellular organelles'. It was commonly believed that they were ancestral to higher eukaryotes which appeared later in evolution. They were also thought to divide by a process of asexual reproduction called `amitosis' which was not seen in eukaryotes. In the last 15 years, molecular biology has eradicated many of these myths and established that parasitic protozoa are not primitive— but are actually very complex, often exhibiting `atypical' characteristics when compared to other eukaryotes.

In addition to a review of the evolution of eukaryotic diversity and an article on genetic diversity this special issue also brings together key articles on adhesion, signalling, differ-entiation, cytopathic molecules, and cell cycle of amoeba.

Frontiers in materials science and technology

Guest Editors: S. Basu and P. Bhargava

Bulletin of Materials Science, Vol. 25, No.6, Nov. 2002, pp. 449_582

As part of the golden jubilee celebrations of IIT, Kharagpur,

a national conference on "Frontiers in materials science

and technology" was held in February 2002. Electronic materials, ceramics, polymers and composites formed the subject matter of the conference. The papers presented included critical reviews and experimental results of strategic materials used in defence, medical and consumer sectors and on the current development of materials including nanomaterials, nanostructures, smart materials and MEMS.

This special issue contains 32 articles presented at the conference from across the country.

Heavy ion accelerator technology

Guest Editors: A. Roy, S. K. Datta, M. B. Kurup and S.Kailas

Pramana, Vol. 59, Nos. 5/6, Nov./Dec. 2002, pp. 703_1098

The ninth international conference on "heavy-ion accelerator technology" was held in New Delhi during January 2002. The topics covered were: Electrostatic accelerators, booster acc-elerators, superconducting structures, RFQs, acceleration of radioactive ion beams, accelerator mass spectroscopy, ion sources, heavy ion injectors, and cryogenics for boosters. The presentations covered the operational experiences of existing accelerator facilities, the progress in the implementation of approved projects and the direction of advancement of future heavy ion accelerator systems.

The papers presented were brought out as two issues of Pramana. The forty contributions were divided among the following topics: electrostatic accelerators, ion sources, LINAC and boosters, radioactive ion beams, future accelerators, radio frequency quadrupoles, beam transport/beam dynamics/control system/electronics, and accelerator mass spectrometry.