Energetic Polymers

High energy materials are essential ingredients in both rocket and explosive formulations. These can be vulnerable due to maltreatment. During gulf war, several catastrophic accidents have been reported from their own payload munitions. The role of energetic binders here was to wrap the explosive formulations to convert it into insensitive munitions. With the aid of energetic binders, the explosive charges are not only protected from tragic accidents due to fire, bullet impact, adjacent detonation, unplanned transportation, but also form total energy output presumption. The use of energetic binders in rocket propellants and explosive charges has been increased after the Second World War. Inert binders in combination with energetic materials, performed well as binders but they diluted the final formulation. Obviously the total energy output was reduced. Currently, the research in the field of energetic polymers is an emerging area, since it plays crucial role in insensitive munitions. The present work emphasises on the synthesis and characterization of oxetanes, oxiranes and polyphosphazene based energetic polymers. The thesis is structured into six chapters. First part of chapter 1 deals with brief history of energetic polymers. The second part describes a brief literature survey of energetic polymers based on oxetanes and oxiranes. Third and fourth parts deal with energetic plasticizers and energetic polyphosphazenes. Finally, the fifth part deals with the various characterization techniques adopted for the current study and sixth part includes objectives of the present work.

Methylene Blue Doped Polymers: efficient Media for Optical Recording

Polymer materials find application in optical storage technology, namely in the development of high information density and fast access type memories. A new polymer blend of methylene blue sensitized polyvinyl alcohol (PVA) and polyacrylic acid (PAA) in methanol is prepared and characterized and its comparison with methylene blue sensitized PVA in methanol and complexed methylene blue sensitized polyvinyl chloride (CMBPVC) is presented. The optical absorption spectra of the thin films of these polymers showed a strong and broad absorption region at 670-650 nm, matching the wavelength of the laser used. A very slow recovery of the dye on irradiation was observed when a 7:3 blend of polyvinyl alcohol/polyacrylic acid at a pHof 3.8 and a sensitizer concentration of 4.67 10 5 g/ml were used. A diffraction efficiency of up to 20% was observed for the MBPVA/alcohol system and an energetic sensitivity of 2000 mJ/cm2 was obtained in the photosensitive films with a spatial frequency of 588 lines/mm.

Methylene Blue Doped Polymers:Efficient Media for Optical Recording

Polymer materials find application in optical storage technology, namely in the development of high information density and fast access type memories. A new polymer blend of methylene blue sensitized polyvinyl alcohol (PVA) and polyacrylic acid (PAA) in methanol is prepared and characterized and its comparison with methylene blue sensitized PVA in methanol and complexed methylene blue sensitized polyvinyl chloride (CMBPVC) is presented. The optical absorption spectra of the thin films of these polymers showed a strong and broad absorption region at 670-650 nm, matching the wavelength of the laser used. A very slow recovery of the dye on irradiation was observed when a 7:3 blend of polyvinyl alcohol/polyacrylic acid at a pHof 3.8 and a sensitizer concentration of 4.67 10 5 g/ml were used. A diffraction efficiency of up to 20% was observed for the MBPVA/alcohol system and an energetic sensitivity of 2000 mJ/cm2 was obtained in the photosensitive films with a spatial frequency of 588 lines/mm.

Twin peak distribution of electron emission profile and impact ionization of ambient molecules during laser ablation of silver target

Laser-induced plasma generated from a silver target under partial vacuum conditions using the fundamental output of nanosecond duration from a pulsed Nd:yttrium aluminum garnet laser is studied using a Langmuir probe. The time of flight measurements show a clear twin peak distribution in the temporal profile of electron emission. The first peak has almost the same duration as the laser pulse while the second lasts for several microseconds. The prompt electrons are energetic enough ('60 eV) to ionize the ambient gas molecules or atoms. The use of prompt electron pulses as sources for electron impact excitation is demonstrated by taking nitrogen, carbon dioxide, and argon as ambient gases.

Emission characteristics and dynamics of C2 from laser produced graphite plasma

The emission features of laser ablated graphite plume generated in a helium ambient atmosphere have been investigated with time and space resolved plasma diagnostic technique. Time resolved optical emission spectroscopy is employed to reveal the velocity distribution of different species ejected during ablation. At lower values of laser fluences only a slowly propagating component of C2 is seen. At high fluences emission from C2 shows a twin peak distribution in time. The formation of an emission peak with diminished time delay giving an energetic peak at higher laser fluences is attributed to many body recombination. It is also observed that these double peaks get modified into triple peak time of flight distribution at distances greater than 16 mm from the target. The occurrence of multiple peaks in the C2 emission is mainly due to the delays caused from the different formation mechanism of C2 species. The velocity distribution of the faster peak exhibits an oscillating character with distance from the target surface.

Judicial Creativity in Constitutional Interpretation

The focus of study in this thesis is on the necessity and extent of judicial creativity in interpreting provisions in certain crucial areas in the Constitution of India. Judicial innovation was essential to adapt the constitutional provisions to modern changed context. Creativity of the Court has been mainly in the creation and introduction of certain new concepts not found in any specific provision of the Constitution which, but were essential for its meaningful interpretation.Independence of the judiciary, basic structure and certain elements of social justice cherished as ideal by the makers of the Constitution are some such concepts infused into the Constitution by the judiciary. The second aspect of creativity lies in the attempt of the Court to construe provisions in the Constitution with a view to upholding and maintaining the concepts so infused into the Constitution. Introduction of those concepts into the Constitution was necessary and is justified. all important features of the Constitution like democratic form of government, federal structure, judicial review, independence of judiciary and rule of law were thus included in the doctrine to prevent their alteration by amendments.As a result of such a construction, the nature of those directive principles itself has changed. They ceased to be mere directives for state action but became mandate for it. If left to legislative or executive will for their implementation, the directives would have remained enforceable as ordinary right.To conclude, notwithstanding the errors committed by the Supreme Court in construing the provisions in the above areas, they stand testimony to its creative and innovative response in interpreting the Constitution. If this trend is continued, it will be possible to achieve through the judicial process, maintenance of independence of the judiciary, avoidance of destruction of the Constitution through the process of amendment and realisation of social justice envisaged in the directive principles. It can be hoped that the Court would maintain its energetic and vibrant mind and rise up to the occasions and extend the same to other areas in future.

Mass Transport In The Equatorial Indian Ocean

In the equatorial oceans, the meridional currents are far less energetic than their zonal counterparts. The response of the Equatorial Indian Ocean to the seasonal reversals in the zonal wind field. is quite interesting and unique. A modest attempt, considering the shortcomings in the hydrographic data availability and distribution, is made to evaluate the variability in the zonal transport of mass. in_ both space and time. The peculiarities in its hydrological regime imposed upon by the seasonally varying winds is best appreciated when compared with the quasi permanent circulation characteristics of the Pacific and Atlanti'c.The major features of the tequatorial mass transport is outlined in the introductory chapter of this thesis for the Pacific and Atlantic Mass transport studies in the Indian Ocean, as can be seen from the earlier studies, gis“ the least known and understood, though could have captured the attention of both the experimentalist and the theoretician alike. owing to its complexity. Since in the Indian Ocean, the studies on the zonal mass transport are limited and are confined to the equator only, an attempt has been made to compute the mass transport extending from 5 N to 20 S.

Biochemical effects of cadmium, salinity and temperature on the catabolism of proteins and purines in oreochromis mossambicus (Peters)

In the present investigation, three important stressors: cadmium ion (Cd++), salinity and temperature were selected to study their effects on protein and purine catabolism of O. mossambicus. Cadmium (Cd) is a biologically nonessential metal that can be toxic to aquatic animals. Cadmium is a trace element which is a common constituent of industrial effluents. It is a non-nutrient metal and toxic to fish even at low concentrations. Cadmium ions accumulate in sensitive organs like gills, liver, and kidney of fish in an unregulated manner . Thus; the toxic effects of cadmium are related to changes in natural physiological and biochemical processes in organism. The mechanics of osmoregulation (i.e. total solute and water regulation) are reasonably well understood (Evans, 1984, 1993), and most researchers agree that salinities that differ from the internal osmotic concentration of the fish must impose energetic regulatory costs for active ion transport. There is limited information on protein and purine catabolism of euryhaline fish during salinity adaptation. Within a range of non-lethal temperatures, fishes are generally able to cope with gradual temperature changes that are common in natural systems. However, rapid increases or decreases in ambient temperature may result in sub lethal physiological and behavioral responses. The catabolic pathways of proteins and purines are important biochemical processes. The results obtained signifies that O. mossambicus when exposed to different levels of cadmium ion, salinity and temperature show great variation in the catabolism of proteins and purines. The organism is trying to attain homeostasis in the presence of stressors by increasing or decreasing the activity of certain enzymes. The present study revealed that the protein and purine catabolism in O. mossambicus is sensitive to environmental stressors.