Evidence for blueshift by weak exciton confinement and tuning of bandgap in superparamagnetic nanocomposites

Superparamagnetic nanocomposites based on Y-Fe2O3 and sulphonated polystyrene were synthesised by ion-exchange process and the structural characterisation has been carried out using X-ray diffraction technique. Doping of cobalt in to the Y-Fe2O3 lattice was effected in situ and the doping was varied in the atomic percentage range 1–10. The optical absorption studies show a band gap of 2.84 eV, which is blue shifted by 0.64 eV when compared to the reported values for the bulk samples (2.2 eV). This is explained on the basis of weak quantum confinement. Further size reduction can result in a strong confinement, which can yield transparent magnetic nanocomposites because of further blue shifting. The band gap gets red shifted further with the addition of cobalt in the lattice and this red shift increases with the increase in doping. The observed red shift can be attributed to the strain in the lattice caused by the anisotropy induced by the addition of cobalt. Thus, tuning of bandgap and blue shifting is aided by weak exciton confinement and further red shifting of the bandgap is assisted by cobalt doping.

Studies on the Effects of Bottom Trawling on the Benthic Fauna off Veraval Coast, Gujarat

Bottom trawling is one among the most destructive human induced physical disturbances inflicted to seabed and its living communities. The bottom trawls are designed to tow along the sea floor, which on its operation indiscriminately smashes everything on their way crushing, killing, burying and exposing to predators the benthic fauna. Bottom trawling causes physical and biological damages that are irreversible, extensive and long lasting. The commercial trawling fleet of India consists of 29,241 small and medium-fishing boats. The northwest coast of India has the largest fishing fleet consisting of 23,618 mechanized vessels, especially the bottom trawlers. However, attempts were not made to study the impact of bottom trawling along Northwest coast of India. The estimated optimum fleet size of Gujarat is 1,473 mechanised trawlers while 7402 commercial trawlers are operated from the coast of Gujarat. Veraval port was designed initially for 1,200 fishing trawlers but 2793 trawlers are being operated from this port making it the largest trawler port of Gujarat. The aim of this study was to investigate the effects of bottom trawling on the substratum and the associated benthic communities of commercial trawling grounds of Veraval coast. The study compared the differences between the samples collected before and after experimental trawling to detect the impacts of bottom trawling. Attempts were made to assess the possible impact of bottom trawling on:(i) the sediment characteristics (ii)the sediment heavy metals (iii) epifauna (iv) macrobenthos and (v) meiobenthos. This study is expected to generate information on trawling impacts of the studied area that will help in better management of the biological diversity and integrity of the benthic fauna off Veraval coast. An exhaustive review on the studies conducted around the world and in India on impact of bottom trawling on the benthic fauna is also detailed.In the present study, the bottom trawling induced variations on sediment organic matter, epifauna, macrobenthos and meiobenthos were evident. It was also observed that the seasonal/ natural variations were more prominent masking the trawling effect on sediment texture and heavy metals. Enforcement of control of excess bottom trawlers and popularization of semi pelagic trawls designed to operate a little distance above the sea bottom for off bottom resources will minimize disturbance on the sea bottom. Training and creating awareness in responsible fishing should be made mandatory requirements, to the coastal communities. They should be made wardens to protect the valuable resources for the benefit of sustainability. To protect the biodiversity and ecosystem health, the imminent need is to survey and make catalogue, identification of sensitive areas or hot spots and to adopt management strategies for the conservation and biodiversity protection of benthic fauna. The present study is a pioneering work carried out along Veraval coast. This thesis will provide a major fillip to the studies on impact of bottom trawling on the benthic fauna along the coast of India.

Studies on nonlinear dynamics of certain reaction systems

The nonlinear dynamics of certain important reaction systems are discussed and analysed in this thesis. The interest in the theoretical and the experimental studies of chemical reactions showing oscillatory dynamics and associated properties is increasing very rapidly. An attempt is made to study some nonlinear phenomena exhibited by the well known chemical oscillator, the BelousovZhabotinskii reaction whose mathematical properties are much in common with the properties of biological oscillators. While extremely complex, this reaction is still much simpler than biological systems at least from the modelling point of view. A suitable model [19] for the system is analysed and the researcher has studied the limit cycle behaviour of the system, for different values of the stoichiometric parameter f, by keeping the value of the reaction rate (k6) fixed at k6 = l. The more complicated three-variable model is stiff in nature.

Analysis discrete function theory

There is a recent trend to describe physical phenomena without the use of infinitesimals or infinites. This has been accomplished replacing differential calculus by the finite difference theory. Discrete function theory was first introduced in l94l. This theory is concerned with a study of functions defined on a discrete set of points in the complex plane. The theory was extensively developed for functions defined on a Gaussian lattice. In 1972 a very suitable lattice H: {Ci qmxO,I qnyo), X0) 0, X3) 0, O < q < l, m, n 5 Z} was found and discrete analytic function theory was developed. Very recently some work has been done in discrete monodiffric function theory for functions defined on H. The theory of pseudoanalytic functions is a generalisation of the theory of analytic functions. When the generator becomes the identity, ie., (l, i) the theory of pseudoanalytic functions reduces to the theory of analytic functions. Theugh the theory of pseudoanalytic functions plays an important role in analysis, no discrete theory is available in literature. This thesis is an attempt in that direction. A discrete pseudoanalytic theory is derived for functions defined on H.

Studies On Pobtunid Crabs [Crustacea Decapoda Brachyura)

True crabs are the most fascinating group of organisms among the decapod crustaceans. Great importance is attached at present to the increased exploitation of these animals and therefore there is great scope for further development of their fishery. They have a broad and hard carapace, massive chelate legs, bent abdomen and exhibit high degree of adaptation to the environment. They show pelagic, benthic, intertidal, burrowing and terrestrial modes of life. Their commensal association with other invertebrates, their breeding behaviour and life history are of great interest to biologists. More than six hundred species of crabs are known to occur in Indian waters and among them about eight species form a regular fishery along the entire stretch of peninsular India (Rao §§_al., 1973) round the year. Crab fishery in India is fast developing and there is vast scope for them as there are many more potential species. Among the various crustacean diets, crabs are celebrated for deliciousness and for nutritional richness. In recent days, crab food items have become more popular and gained global reception. These resources can also be augmented further by culturing them in ponds in the future. Information on biology and ecology of constituent species go a long way not only in effective exploitation and regulation of the respective fishery resources but also helps in evolving a suitable gear for their capture. Information collected on the national level in various aspects as reproduction, growth rate, larval development, parasites, diseases, nutritive values etc. will be of help in evolving a national policy for the effective utilisation and conservation of this resource. They also provide the baseline information for undertaking any purposeful and meaningful culture activities. Information on the various aspects mentioned above is very much restricted in true crabs and hence the present study

Effect of cobalt doping on the magnetic properties of superparamagnetic g-Fe2O3-polystyrene nanocomposites

Superparamagnetic nanocomposites based on g-Fe2O3 and sulphonated polystyrene have been synthesized by ion exchange process and the preparation conditions were optimized. Samples were subjected to cycling to study the effect of cycling on the magnetic properties of these composites. The structural and magnetization studies have been carried out. Magnetization studies show the dependence of magnetization on the number of ion exchange cycles. Doping of cobalt at the range in to the g-Fe2O3 lattice was effected in situ and the doping was varied in the atomic percentage range 1–10. The exact amount of cobalt dopant as well as the iron content was estimated by Atomic Absorption Spectroscopy. The effect of cobalt in modifying the properties of the composites was then studied and the results indicate that the coercivity can be tuned by the amount of cobalt in the composites. The tuning of both the magnetization and the coercivity can be achieved by a combination of cycling of ion exchange and the incorporation of cobalt

Educational Loans And The Higher Education Sector In India

In 2001 the Indian Banks Association have come up with a model frame work for educational loans in the country. With the approval of the Central Government the public sector banks in India started to give education loans. The private and cooperative banks also joined the fray. Due to growing NPAs and the intervention of the Government these norms were modified in 2011. The budget allocation for the primary and higher secondary education is on the increase in India. However, higher education has been of late relegated or left to the mercy of the private players. There has been a steady growth of educational loans disbursed, private colleges and deemed universities started and enrolments of students in higher education during the years 2001 to 2011. This paper is a humble attempt to 1) analyse the growth of the educational loans vis-à-vis other forms of personal loans at the national level, 2) showcase the disbursements of educational loans in Kerala State, 3) to assess the growth of educational institutions and enrolment of students in higher education in India from secondary data and 4) to make suggestions based on the findings