1,10-phenanthroline (phen), 2,2′-bipyridyl (bipy), pyridine (py) and 4-picoline (4-pic) complexes of dibutyltindichloride (Bu2SnCl2) and dimethyltindichloride (Me2SnCl2) were synthesized. The complexes were characterized with the help of elemental analyses, IR spectra and thermal analyses. The complexes were found to have the compositions [Bu2SnCl2·phen], [Bu2SnCl2·bipy], [Me2SnCl2·phen], [Me2SnCl2·bipy], [Me2SnCl2·2py] and [Me2SnCl2·2(4-pic)]·H2O. All these complex compounds appeared to posses octahedral structures. Thermodynamic parameters, such as activation energyEa* enthalpy change ΔH and entropy change ΔS, for the dehydration and sublimation of the complexes were evaluated using some standard methods.
Variable temperature /303–553 K/ IR spectroscopic studies are made during thermal decomposition of pure and -treated ammonium perchlorate /AP/. Decomposition is enhanced by radiation or in the presence of an additive /Gd2O3/. Intensity of the stretching /1100 cm–1/ and bending /625 cm–1/ frequencies of ClO
decrease on heating the KBr matrix even below 360 K. Above this temperature, a broad band develops over 480–510 cm–1 in the pure and -treated AP which is attributed to ClO
Authors:V. Dedgaonkar, S. Mitra, and Sunil Waghmare
Halogen recoil following /n, / reaction has been studied in some heterocyclic systems. The organic yields are 60% for irradiation as solids: exceptions are dioxanide furoate /34%/ and 5-chloro isatoic anhydride /31%/. As solutions in 11 THF + benzene and 11 HTF+DMSO, these yields are lower by 10% and decrase further when only THF is the solvent. Mass-spectroscopy data revealed the possible fragmentation pattern.
Authors:V. Dedgaonkar, S. Mitra, and Sunil Waghmare
Phase change effects on the total organic yield have been studied in crystalline chlorobenzene derivatives activated by radiative neutron capture. Irradiation of the compounds in benzene solution decreased the organic yield considerably while these values remained unchanged when 11 benzene + DMSO or 11 benzene + acetonitrile solvent mixtures were used, the 11 benzene + THF solvent gave the lowest yield in all the cases. Heat treatment to the neutron activated solids enhanced the organic yield only in the case of 2-amino 5-chlorobenzophenone by 7%.
DSC and TG studies were carried out on γ -radiation processed Indian natural products of medicinal importance, namely Ashwagandha
(Withania Somnifera), Amla (Emblica Officinalis) and Hartiki (Terminalia chebula). DSC thermoanalytical curves were recorded
from 35 to 400C in air and nitrogen atmosphere. Similarly, TG thermoanalytical curves were taken from 35 to 700C in air
and nitrogen atmosphere. Irradiated products gave significantly different thermoanalytical profiles in comparison to non-irradiated
samples. The differences were observed above decomposition temperature of 200C and were non-linear with respect to radiation
dose. Partial oxidation of the products during irradiation in air could be responsible for the observed differences.
We are developing a scanning spectroscopy system to measure prompt gammas-rays induced by inelastic neutron scattering and
thermal neutron capture to non-invasively analyze soil in situ. Using a radiation source, a 14 MeV (d,t) neutron generator
(NG), in a close proximity to the detection system without any precautions will flood and saturate the detectors with direct
radiation. Therefore, we devized and partially optimized a shadow shielding sited between the source and the detection system;
we discuss our experimental results and basic Monte Carlo calculations.
It is proposed to use 14 MeV neutrons tagged by the associated particle neutron time-of-flight technique (APnTOF) to identify
the fillers of unexploded ordnances (UXO) by characterizing their carbon, nitrogen and oxygen contents. To facilitate the
design and construction of a prototype system, a preliminary simulation model was developed, using the Geant4 toolkit. This
work established the toolkit environment for (a) generating tagged neutrons, (b) their transport and interactions within a
sample to induce emission and detection of characteristic gamma-rays, and (c) 2D and 3D-image reconstruction of the interrogated
object using the neutron and gamma-ray time-of-flight information. Using the modeling, this article demonstrates the novelty
of the tagged-neutron approach for extracting useful signals with high signal-to-background discrimination of an object-of-interest
from that of its environment. Simulations indicated that an UXO filled with the RDX explosive, hexogen (C3H6O6N6), can be identified to a depth of 20 cm when buried in soil.
Differential scanning calorimeter (DSC) has been used to study the dehydration characteristics of hydrated calcium aluminates such as CA, CA2 and C12A7 where C and A stand for CaO and Al2O3 respectively. Dehydration of CAH10 and C2AH8 (whereH=H2O) occur ∼ at 160–180°C and 200–280°C respectively. These two phases are unstable and ultimately get transformed to AH3 and C3AH6. Dehydration of AH3 and C3AH6 occur between 290 and 350°C and overlap at lower scanning rate. The activation energy for dehydration of the stable AH3 and C2AH6 phases has been found to be 107.16 and 35.58 kJ mol−1 respectively. The compressive strength of the hydrated calcium aluminates has been determined. The result shows that in the case of CA, almost 90% of ultimate strength has been attained in 1 day whereas in CA2, ultimate strength has been attained in 14 days and in C12A7 in 1 day. DSC results have been correlated with the rate of strength developments.