Puducherry, India
Puducherry, India

Pondicherry University is a central university in Puducherry, India. Founded in 1985 by the Government of India, the university is a collegiate university with a jurisdiction spread over the Union Territories of Puducherry, Lakshadweep and Andaman and Nicobar Islands.It has 35000 students in its 87 affiliated colleges including 27,000 students in the distance education mode. The current strength of students studying on-campus stands at 6500. It has introduced innovations like the Choice-based Credit System and on-line admission for postgraduate studies. Pondicherry University is ranked as one of the top ten Universities in India based on the survey conducted on 2013. Wikipedia.


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Raam Dheep G.,Pondicherry University | Sreekumar A.,Pondicherry University
Energy Conversion and Management | Year: 2014

Thermal energy storage system plays a critical role in developing an efficient solar energy device. As far as solar thermal devices are concerned, there is always a mismatch between supply and demand due to intermittent and unpredictable nature of solar radiation. A well designed thermal energy storage system is capable to alleviate this demerit by providing a constant energy delivery to the load. Many research works is being carried out to determine the suitability of thermal energy storage system to integrate with solar thermal gadgets. This review paper summarizes the numerous investigations on latent heat thermal energy storage using phase change materials (PCM) and its classification, properties, selection criteria, potential research areas and studies involved to analyze the thermal-physical properties of PCM. © 2014 Elsevier Ltd. All rights reserved.


Anatase nanoparticles, Co xTi 1-xO 2-δ (x = dopant density in at % and δ = concentration of oxygen vacancy in the lattice) were synthesized using UV (' = 254 nm)-induced photoreduction of surface preadsorbed cis-[Co III(en) 2(MeNH 2)Cl] 2+ complex ion on nanoscale TiO 2 particle surfaces in an aqueous solution. Photogenerated dopant, Co II, has successfully implanted in the semiconductor host lattice, preserving anatase crystal phase without the formation of impurity phase like rutile. Such materials termed as diluted magnetic semiconductors (DMSs), if realized without undesirable phases, are projected to have significant implications for the evolving fields of spintronics and advanced magneto-optics. The light dosage was systematically varied to prepare nanostructured semiconductor particles with varying dopant density in the anatase matrix leading to: x%,Co/nano-TiO 2; 0.91 ≤ x ≤ 1.26 at % nonstoichiometric compound. The compound has been found to show altered optical, compositional, and room-temperature ferromagnetic properties with respect to the undoped TiO 2 nanoparticles. X-ray diffraction measurements showed characteristic anatase reflections and supplied information about the absence of coexisting rutile impurity phase. The nanoparticles are ferromagnetic, having their hysteresis loops in the range -4000 Oe < H < +4000 Oe with the specific magnetizations of (14.40 to 0.196) × 10 -3 μ B/ Co II at 300 K. However, the magnetic property depends critically on oxygen vacancy (V 0 O, V + O) and the Co content. A combined study of PL, XRF, SEM-EDX, HRTEM, XPS, and Raman techniques was used to investigate the size, dopant-distribution, composition, and surface structure. Cobalt dopant is predominantly substitutional, Co II sub in anatase lattice and in +2 formal oxidation state. SEM and HRTEM images revealed obvious variations in the surface morphology of raw and Co implanted anatase. This strategy provides an alternative route to synthesize nanosized phase pure anatase x%,Co/nano-TiO 2 showing room temperature ferromagnetism, which is expected to open up a general method for the synthesis of other transition-metal-doped nano-TiO 2. © 2011 American Chemical Society.


Abbasi T.,Pondicherry University | Abbasi S.A.,Pondicherry University
Renewable and Sustainable Energy Reviews | Year: 2011

There is a great resurgence of interest all over the world in the development of 'small' hydropower systems (SHS). The surge is essentially propelled by the belief that SHS, which include mini, micro, and picahydel systems, are a source of clean energy with little or no adverse impacts on the environment. This paper presents an overview of SHS and then examines in detail whether the prevalent belief in the great environment-friendliness of SHS is really justified. It is brought out that widespread use of SHS is likely to cause, per kilowatt of power generated, no less significantly adverse environmental impacts than large hydropower systems and some other conventional sources of energy. While supporting the ongoing global efforts to maximize the use of SHS, the authors advocate much greater circumspection than is being exercised at present vis-a-vis SHS. The authors believe that if the likely pitfalls are foreseen before SHS are put to widespread use, and remedial measures taken accordingly, it may save the world from considerable disillusionment and environmental damage. © 2010 Elsevier Ltd. All rights reserved.


Narayanan K.B.,Pondicherry University | Sakthivel N.,Pondicherry University
Advances in Colloid and Interface Science | Year: 2010

An array of physical, chemical and biological methods have been used to synthesize nanomaterials. In order to synthesize noble metal nanoparticles of particular shape and size specific methodologies have been formulated. Although ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques have been used successfully to produce nanoparticles, they remain expensive and involve the use of hazardous chemicals. Therefore, there is a growing concern to develop environment-friendly and sustainable methods. Since the synthesis of nanoparticles of different compositions, sizes, shapes and controlled dispersity is an important aspect of nanotechnology new cost-effective procedures are being developed. Microbial synthesis of nanoparticles is a green chemistry approach that interconnects nanotechnology and microbial biotechnology. Biosynthesis of gold, silver, gold-silver alloy, selenium, tellurium, platinum, palladium, silica, titania, zirconia, quantum dots, magnetite and uraninite nanoparticles by bacteria, actinomycetes, fungi, yeasts and viruses have been reported. However, despite the stability, biological nanoparticles are not monodispersed and the rate of synthesis is slow. To overcome these problems, several factors such as microbial cultivation methods and the extraction techniques have to be optimized and the combinatorial approach such as photobiological methods may be used. Cellular, biochemical and molecular mechanisms that mediate the synthesis of biological nanoparticles should be studied in detail to increase the rate of synthesis and improve properties of nanoparticles. Owing to the rich biodiversity of microbes, their potential as biological materials for nanoparticle synthesis is yet to be fully explored. In this review, we present the current status of microbial synthesis and applications of metal nanoparticles. © 2010 Elsevier B.V. All rights reserved.


Abbasi T.,Pondicherry University | Abbasi S.A.,Pondicherry University
Renewable and Sustainable Energy Reviews | Year: 2010

Biomass is the first-ever fuel used by humankind and is also the fuel which was the mainstay of the global fuel economy till the middle of the 18th century. Then fossil fuels took over because fossil fuels were not only more abundant and denser in their energy content, but also generated less pollution when burnt, in comparison to biomass. In recent years there is a resurgence of interest in biomass energy because biomass is perceived as a carbon-neutral source of energy unlike net carbon-emitting fossil fuels of which copious use has led to global warming and ocean acidification. The paper takes stock of the various sources of biomass and the possible ways in which it can be utilized for generating energy. It then examines the environmental impacts, including impact vis a vis greenhouse gas emissions, of different biomass energy generation-utilization options. © 2009 Elsevier Ltd. All rights reserved.


Abbasi T.,Pondicherry University | Abbasi S.A.,Pondicherry University
Renewable and Sustainable Energy Reviews | Year: 2011

The increasingly manifest impacts of global warming have made it a global priority to phase out the use of petrol and diesel as transportation fuels in favour of hydrogen. But the production of hydrogen by most existing technologies entails substantial use of fossil fuels and CO2 emissions; indeed as much as 2.5-5 tonnes of carbon is released as CO2 per tonne of hydrogen currently produced by conventional means. Hence the production of hydrogen can be 'carbon-free' only if it is generated by employing genuinely carbon-free renewable energy sources. The present review deals with the options, prospects, and challenges associated with this very high-priority area of global concern. © 2011 Elsevier Ltd. All rights reserved.


Narayanan K.B.,Pondicherry University | Sakthivel N.,Pondicherry University
Advances in Colloid and Interface Science | Year: 2011

The size, shape and controlled dispersity of nanoparticles play a vital role in determining the physical, chemical, optical and electronic properties attributing its applications in environmental, biotechnological and biomedical fields. Various physical and chemical processes have been exploited in the synthesis of several inorganic metal nanoparticles by wet and dry approaches viz., ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques. However, these methodologies remain expensive and involve the use of hazardous chemicals. Therefore, there is a growing concern for the development of alternative environment friendly and sustainable methods. Increasing awareness towards green chemistry and biological processes has led to a necessity to develop simple, cost-effective and eco-friendly procedures. Phototrophic eukaryotes such as plants, algae, and diatoms and heterotrophic human cell lines and some biocompatible agents have been reported to synthesize greener nanoparticles like cobalt, copper, silver, gold, bimetallic alloys, silica, palladium, platinum, iridium, magnetite and quantum dots. Owing to the diversity and sustainability, the use of phototrophic and heterotrophic eukaryotes and biocompatible agents for the synthesis of nanomaterials is yet to be fully explored. This review describes the recent advancements in the green synthesis and applications of metal nanoparticles by plants, aquatic autotrophs, human cell lines, biocompatible agents and biomolecules. © 2011 Elsevier B.V. All rights reserved.


Abbasi T.,Pondicherry University | Abbasi S.A.,Pondicherry University
Renewable and Sustainable Energy Reviews | Year: 2012

Anaerobic reactors have acquired a new relevance in recent years due to their ability to generate methane from biodegradable wastewaters - thereby producing clean energy. Methane capture in this manner also prevents the escape of the greenhouse gas to the atmosphere which otherwise occurs when anaerobic conditions develop in drains and outfalls carrying wastewater. Of all the different types of anaerobic reactors in vogue - anaerobic filter, downflow fixed-film reactor, expanded fluidized-bed anaerobic reactor, etc. - the upflow anaerobic sludge blanket (UASB) reactor is arguably the most widely used. Nearly 80% of the world's anaerobic wastewater treatment systems are estimated to be based on the UASB technology. The functioning of a UASB reactor revolves round its sludge bed which gets expanded as the wastewater is made to flow vertically upwards through it. It is the microflora attached to the sludge particles which acts upon the wastewater. Hence the quality of biofilms sported by the sludge particles, and the intimacy of the sludge-wastewater contact are the factors which, principally, govern the success of a UASB reactor. Very early in the development of UASB technology it was realized that granular sludge of appropriate particle size, particle density, and microfilm characteristics enhances the reactor efficiency in terms of the rate as well as the extent of wastewater treatment. From then onwards efforts have been made by scientists across the world to understand the factors which shape the granules and the manner in which the granules contribute to wastewater treatment. The state-of-the-art is presented in this paper. © 2011 Elsevier Ltd. All rights reserved.


Bhowmik R.N.,Pondicherry University
Journal of Magnetism and Magnetic Materials | Year: 2011

The present paper shows that bulk La0.67Ca 0.33MnO3 (LCMN) sample of micron size particles is a typical ferromagnet and magnetic properties of LCMN samples with particle size in the nanometer scale are better described in the frame work of a ferrimagnetic structure. Detailed analysis of the temperature dependence of the inverse of paramagnetic susceptibility has confirmed the signature of ferrimagnetism in the nano-sized particles of LCMN. We have explained the observed ferrimagnetism as an effect of modified magnetic properties in the coreshell spin structure of LCMN particles, irrespective of the nanocrystalline and amorphous phase of the material. © 2010 Elsevier B.V. All rights reserved.


Major, trace and REE compositions of sediments from the upper Ganga River and its tributaries in the Himalaya have been examined to study the weathering in the Himalayan catchment region and to determine the dominant source rocks to the sediments in the Plains. The Ganga River rises in the Higher Himalaya from the Higher Himalayan Crystalline Series (HHCS) bedrocks and traverses over the Lesser Himalayan Series (LHS) and the Himalayan foreland basin (Siwaliks) rocks before entering into the Gangetic Plains. The major element compositions of sediments, reflected in their low CIA values (45.0-54.7), indicate that silicate weathering has not been an important process in the Himalayan catchment region of the Ganga River. Along the entire traverse, from the HHCS through LHS and the Siwaliks, the sediments from the tributaries and the mainstream Ganga River show higher Na2O, K2O, CaO and silica. This, and the higher ratios of La/Sc, Th/Sc and lower ratios of Co/Th, suggest that the source rocks are felsic. The fractionated REE patterns and the significant negative Eu anomalies (Eu/Eu* = 0.27-0.53) indicate highly differentiated source. Moreover, the comparison of the sediments with different source rock lithologies from the HHCS and the LHS for their major elements clearly suggests that the HHCS rocks were the dominant source. Further, comparison of their UCC (upper continental crust) normalized REE patterns suggests that, among the various HHCS rocks, the metasediments (para-gneiss and schist) and Cambro-Ordovician granites have formed the major source rocks. The Bhagirathi and Alaknanda River sediments are dominantly derived from metasediments and those in the Mandakini River from Cambro-Ordovician granites. The resulting composition of the sediments of the Ganga River is due to the mixing of sediments supplied by these tributaries after their confluence at Devprayag. No further change in major, trace and rare earth element compositions of the sediments of the Ganga River after Devprayag up to its exit point to the Plains at Haridwar, suggests little contribution of the Lesser Himalayan and Siwalik rocks to the Ganga River sediments. © 2009 Elsevier B.V. All rights reserved.

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