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First and second order Kα X-ray satellites of the elements Ge, As, Se and Br were investigated by photon excitation. A wavelength dispersive spectrometer with LiF 420 crystal was employed. The energies and relative intensities of these X-ray satellites were measured. Their energy shifts and relative intensities with respect to the Kα diagram line are compared with theoretical estimates. Their dependence on atomic number is also examined.

Trace element concentration of blood serum samples of patients afflicted with Alzheimer’s disease and controls were determined using inductively coupled plasma-mass spectrometry. 22 elements starti...

Two series of copper ferrites are prepared using the chemical compositional formula Cu 1.0 Fe 2.0-2x Mo x O 4.0 and Cu 1.0-3x Fe 2.0 Mo x O 4.0 . They are calcinated at 750 C and sintered at 950C. The grain size initially decreases with Mo 6+ concentration. while it found to increase from x = y = 0.06 (Mo 6+ ) onwards. The monotonic increase of Tc is found in C series materials while in F series it observed to decrease at intermediate values of x. Variation of magnetization has been explained on the basis of Neel's model of magnetic interactions and Yafet-Kittel angle existence. The initial permeability (μ i ) increases at room temperature followed by its fall with the increase of F as well as C series. The observed deviation between experimental and theoretical magnetic moment values is explained in terms of Y-K angle occurrence.

Lithological variations, circular spectral anomalies, geological structures such as folds, faults, lineaments and shear zones of Kutch sedimentary basin were interpreted using IRS-LISS III satellite data. Aeromagnetic data was also interpreted qualitatively and quantitatively and a number of anomalous magnetic zones, faults, lineaments and domal structures were mapped. Magnetic basement depths and thickness of sediments were also computed. A number of alternate basement ridges/highs/uplifted blocks and depressions/lows/downthrown blocks were delineated. The information obtained from satellite remote sensing and aeromagnetic data were then integrated and the results were compared with published literature on gravity, magnetic (ground), magnetotelluric and seismic data, and also with field geology and well data. Structural controls in spatial domain (latitude, longitude and depth) were derived by establishing spatial relationship among different geological structures with reference to the geological time scale. Numerous horst and graben structures (ridges and sub-basins) as well as a number of master faults were delineated which serve as vital information with regard to hydrocarbon prospects and earthquake vulnerability, respectively. Based on the information obtained from this integrated study, a conceptual tectonometamorphic model along with sedimentation and igneous activity (ophiolitic and basaltic) has been constructed which has a significant bearing on the sequence of events that occurred during the deformational history of Kutch sedimentary basin resulting into the present day tectonic configuration.

Two series of copper ferrites are prepared using the chemical compositional formula Cu1.0-3y Fe2.0-2x Mox + yO4.0. They are calcinated at 750 C and sintered at 950C.When x =y = 0.0, the e′ of the basic copper ferrite is probably due to electronic exchange interactions of copper and iron ions as Cu2+↔ Cu1+ and Fe3+↔ Fe2+. The observed value of dielectric constant (є′) decreases as a function of substituent concentration (x) up to x = 0.20 and for further values of ‘x’ it found to increase. In the case of ‘C’ (x = 0) series ferrites є′ decreases with substituent concentration (y) up to y = 0.04, later it found to increase. The dispersion of ac resistivity with frequency is observed indicating their strong dependence on frequency as in the case of dielectric behaviour. These results are explained with different possible mechanisms.

Identification of self-interstitials in molecular dynamics (MD) simulations is of critical importance. There exist several criteria for identifying the self-interstitial. Most of the existing methods use an assumed cut-off value for the displacement of an atom from its lattice position to identify the self-interstitial. The results obtained are affected by the chosen cut-off value. Moreover, these chosen cut-off values are independent of temperature. We have developed a novel unsupervised learning algorithm called Max-Space Clustering (MSC) to identify an appropriate cut-off value and its dependence on temperature. This method is compared with some widely used methods such as effective sphere (ES) method and nearest neighbor sphere (NNS) method. The cut-off radius obtained using our method shows a linear variation with temperature. The value of cut-off radius and its temperature dependence is derived for five bcc (Cr, Fe, Mo, Nb, W) and six fcc (Ag, Au, Cu, Ni, Pd, Pt) crystals. It is seen that the ratio of the cut-off values “r” to the lattice constant “a” lies between 0.23 and 0.3 at 300 K and this ratio is on an average smaller for the fcc crystals. Collision cascade simulations are carried out for Primary knock-on Atom (PKA) energies of 5 keV in Fe (at 300 K and 1000 K) and W (at 300 K and 2500 K) and the results are compared using the various methods.

The ovaries of the beetle Xyleborus ferrugineus reared on standard sawdust diet with an without 0.08% sorbic acid added were examined for differences in ultrastructural development of the oocytes. Indications of vigorous yolk deposition are an extensive rough-surfaced endoplasmic reticulum (RER), numerous electron-dense secretory vesicles and a prominent nucleus in associated follice cells, and extremely electron-opaque material in the interfollicular cell spaces and the perioocytic area. After 6 days of feeding without added sorbic acid, a mature terminal oocyte is present in one of the two ovaries. This terminal oocyte at this mature stage contains yolk spheres and lipid bodies. However, the most mature oocyte in beetles reared on the standard sawdust diet to which 0.08% sorbic acid was added remained at a previtellogenic stage after 6 days of feeding. Titers of ecdysone in 6-day-old adult females reared on standard sawdust without and with 0.08% sorbic acid added were 534.64 ± 20.93 S.D. pg/mg and 39.94 ± 14.71 S.D. pg/mg body weight, respectively.

Based on the three known proposed pathways for the uni-molecular decomposition of RDX, we have formulated the rate equations. A kinetic Monte Carlo code has been developed and used to simulate the uni-molecular decomposition of RDX based on these equations. The KMC simulations allow one to explore each of the decomposition pathways individually and also the three competing pathways at a specified temperature and pressure. The pressure dependence is incorporated using Lindemann's formalism. The code is validated by reproducing the species evolution along each pathway. Amongst the three proposed pathways, the most likely path of RDX decomposition and the time evolution of various molecular species at different ambient temperatures and pressures are obtained. An analytical model has been developed to reproduce the decomposition pathways, which matches the simulation results.

In recent years, due to specific features of compact neutron generators, their demand in elemental analysis and detection of the illicit materials has been increased in scientific community. Compact in size, controlled operation and radiation safety like features of neutron generator is suitable for research work with illicit materials. An accelerator based neutron generator can be operated in steady mode as well as in pulse mode. The main embodiment of this type of generator includes ion source, ion acceleration system and target. We are developing such type of neutron generator. This consists of one in-house developed penning ion source, a single electrode acceleration gap and one deuteriated titanium target or virgin titanium target. The neutron generator was operated at 80 kV acceleration potential, a deuterium pressure of 0.1 mTorr and ion source potential at 1 kV. The neutron generation was confirmed by the solid state nuclear track detector CR-39. In this report, we will discuss various physics and technical issues related to the important components of this generator, operation of the generator and neutron detection.

The measurement of acetylcholinesterase (AChE) activity is used worldwide as a biomarker of environmental contamination due to neurotoxic substances. In the present study the AChE activities was measured in marine snails (Cronia contracta) collected seasonally from six sampling sites (viz. Arambol, Anjuna, Dona Paula, Vasco, Velsao and Palolem) along the Goa coast during the pre-monsoon (April, 2004), monsoon (September, 2004) and post-monsoon (November, 2004) periods. The AChE activities in C. contracta showed wide variation along the Goa coast. It was found to be quite high at the reference site, Palolem (23.97, 21.72 and 24.85) throughout the sampling period (April-November, 2004). The AChE activities in C. contracta decreased significantly at Vasco (44.6-52.4% reduction) followed by Dona Paula (24.9-36.2% reduction), Velasao (10.8-35.9% reduction), Arambol (12.6-37.3% reduction) and Anjuna (0-12.7% reduction). Such a significant variation of AChE activities in the marine snail along the Goa coast can be attributed to neurotoxic substances prevalent in those regions. The high concentration of different neurotoxic metals (lead, cadmium, copper, manganese and iron) and petroleum hydrocarbons in the tissues of the marine snails at Dona Paula, Vasco and Velsao clearly substantiate reduction of AChE activities in C. contracta. The in vitro studies on the inhibition of AChE by different metals and PHC indicated that lead, cadmium and copper are the most predominant inhibitor. Based on the AChE activities in C. contracta the sampling sites along the Goa coast can be classified into three major clusters such as highly contaminated sites (Dona Paula, Vasco and Velsao), moderately contaminated sites (Arambol, Anjuna) and least contaminated site (Palolem).

The importance of specifying the state of the inlet streams in determining the degrees of freedom (DOF) of a process is highlighted in the context of a single-stage separation unit. It is shown that, for the separation of a C-component mixture, the commonly accepted value of 2C + 6 as the DOE of an equilibrium single stage holds only if neither of the inlet streams lie on the phase envelope. The implications of this feature for the DOF of multistage processes is explored. The importance of a precise interpretation of the phase rule in arriving at the above results is emphasized. ? 2005 American Chemical Society.

Process intensification has been the focus of increasing attention in recent years. A volume reduction of distillation and absorption units by a factor of 100 or more using rotating beds has been claimed. Industrial trickle-bed reactors are bulky because the liquid flow and interphase transport of the reacting species are governed by the earth's gravity, as in the case of distillation columns. To explore the possible process intensification in these reactors, we have measured the reaction rates of hydrogenation of α-methyl styrene with palladium as catalyst in the rotating beds of spherical particles and metal foam, which acted as catalyst support. To quantify the intensification achieved, the reaction rates were compared with those of conventional trickle beds. The enhancement in the reaction rates was in the range of 30–40 times in a centrifugal force field of about 450 times the gravitational force field. An industrial reactor of 60 m3 could be replaced with a rotating bed < 1.5 m3 in volume. It appears that there is a possibility of further process intensification. However, the volume reduction is possible only for mass-transfer limited reactions. © 2005 American Institute of Chemical Engineers AIChE J, 2005

The high centrifugal force field in a rotating packed bed (HIGEE) permits the use of packing with a large surface area and enhances the liquid-side mass-transfer coefficient. However, the gas-side mass-transfer coefficient is in the same range as that of the conventional packed columns. Recent studies indicate that the tangential slip velocity between the gas and the packing is negligible. We have split the packing into annular rings to rotate adjacent rings in the counterdirection to promote the tangential slip velocity in the range of 5−30 m/s and to enhance the gas-side mass-transfer coefficient. In this work, we present the frictional and centrifugal pressure drops and the tangential slip velocity of the gas in a HIGEE with split packing. Counter to intuition, the total pressure drop with counterrotation of the rings is found to be less than that with corotation of the rings.

Monthly maps of cyclone heat potential (CHP) in the Bay of Bengalhave been prepared by using Levitus climatological data set. Seasonal variability ofCHP in the Bay of Bengal has been studied using the CTD data sets collected duringfive cruises during the period, 1993–1996. High value (>30 kcal/cm2) of CHP coincided with anticyclonic gyre (ACG) and the low value of CHP (16 kcal/cm2) coincided with thecyclonic gyre (CG). This emphasizes the importance of gyres in the distribution ofCHP, which play an important role in the intensification of cyclones/depressions.CHP is >14 kcal/cm2 over Andaman Sea, southern and Central Bay of Bengal where the generation and movement of cyclones take place during post south west monsoon season (October–November). A depression formed on 07.11.95 at 11°N; 91°E and intensified into a cyclonic storm by 8th November evening and crossed Orissa Coast on 9th November 1995. A few days before its formation, the value of CHP at the origin of thiscyclone was about 20 kcal/cm2. To understand the exact role of CHP in theformation and intensification of cyclones/depressions over Bay of Bengal, more intense and systematic data sets are essential.

A number of magnetic zones, faults, lineaments and domal structures were interpreted based on the analysis of aeromagnetic data. Magnetic basement depth and thickness of the sediments were computed by means of quantitative interpretation techniques. A number of alternate basement ridges/highs/uplifted blocks and depressions/lows/downthrown blocks were also delineated. The lithological variations, major folding and faulting patterns, circular spectral anomalies and other geological structures were interpreted from IRS-1C satellite data. The tectonic framework and deformational history of the basin were deduced. The results obtained from the interpretation of aeromagnetic and satellite data were then integrated and the potential zones of hydrocarbon deposits and vulnerable areas for earthquake occurrence were derived.