In the present work, we have estimated the vacancy migration energy in a single crystal of hcp Zr and also determined the mean energy path for this transition using molecular dynamics based simulations. The vacancy migration energy is estimated to be about 1.02 eV, which is quite close to the experimental and DFT data for hcp-Zr.

La2Mo2O9 based Tb-doped compound, La2-xTbxMo2O9 (x=0.1, 0.2, 0.5), was synthesized and characterised by EIS studies. The frequency and temperature dependent dielectric, electric modulus and ac conductivity studies have been done. Different formalisms have been used to understand relaxation mechanism in our compound. The conductivity in these specimens appears to be due to mobility of oxygen ions.

Four new molecules 1,3,5-trinitrooctahydropyrrolo[3,4-d]imidazole (1), 1,4,6-trinitrooctahydro-1H-pyrrolo[3,4-b]pyrazine (2), tetranitrodecahydropyrrolo [3, 4-f] [1, 3, 5] triazepine (3), 1,2-dinitro-4-(3-nitro-1,3-diazetidin-1-yl)pyrazolidine-3,5-dione (4) were designed and studied the theoretical properties using DFT calculations. All the four molecules were found to exhibit better or comparable properties with the commercially available, widely used explosives RDX, HMX and useful for propellant and explosive applications.

Bioremediation with the help of biosurfactant is one of the promising technologies in treating the hydrocarbon and heavy metal contaminated sites. Biosurfactant was produced naturally by microorganism and hence biodegradable, which is alternative to chemical surfactant for various applications. In this study the biosurfactant producing strain Brevibacillus sp. AVN 13 was used for hydrocarbon and heavy metal remediation. The biosurfactant enhanced biodegradation assay of used engine oil by Brevibacillus sp. AVN 13 was carried out using Erlenmeyer flask experiment and the degradation of hydrocarbon removal rate was analyzed by gas chromatography. The Brevibacillus sp. AVN 13 is having ability to degrade 72 % of hydrocarbon. Then biosurfactant assisted chromium removal process was carried out. The effect of initial chromium concentration, effect of pH, incubation time and concentration of biosurfactant were studied. The removal rate of chromium using biosurfactant was found to be 72.54 % under optimized conditions. Overall this study proved that, biosurfactant from Brevibacillus sp. AVN13 can be effectively used for degradation of oil spilled and heavy metals contaminated sites.

Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitive to shock. Suitable fluorinated polymeric binders will be a potential replacement to the conventional stable but un-energetic hydroxyl-terminated polybutadiene (HTPB) for processing them in a shock insensitive and machinable form without decreasing the overall energy. Synthesis of fluorosubstituted epoxy monomer followed by synthesis of the corresponding fluorinated polymeric binder via cationic ring-opening polymerization is discussed in this paper.

The global alarms of energy security and change of environment have prompted strong research in the field of renewable energy to lessen the impact of environmental effects and health hazard. The present study addresses with pyrolysis kinetics of water hyacinth using thermogravimetric analysis (TGA). The TGA analysis was conducted in the temperature range of 30 to 900 ?C with four heating programs (10, 15, 20 and 30 ?C/min). TGA result shows that the pyrolysis of water hyacinth is categorized by three different stages and most decomposition was observed in the 2 nd pyrolysis stage. The activation energy in this study was determined using isoconversional method i.e. Flynn–Wall–Ozawa and the preexponential coefficient were calculated using Kissinger’s equation. From the analysis it was observed that the average value of activation energy of water hyacinth obtained as 238.75 kJ/mol in the conversion range of 0.1 – 0.8. With the increasing of heating rates, the pre-exponential coefficient was found to decreased and maximum value was obtained at a = 0.6.

PbS/CdS core-shell quantum dots have been synthesized through chemical route. PbS shows polycrystalline cubic structure and CdS shows hexagonal structure. The photoluminescence study shows a blue shift of near band gap emission of core PbS when coated with shell CdS. PbS shows a band gap of 2.2 eV and CdS shows 2.7 eV whereas the PbS/CdS nanocomposite shows a reduction of band gap 1.5 eV. The observed optical properties are clearly carrying evidences of cationic exchange between the lead and cadmium ion complexes. The quantum yield of the composite is greatly enhanced implying its potential for application in optoelectronic devices.

A study on growth of ZnSe nanostructures in wet chemical bath deposition has been made. The structural and optical characterizations of the samples are done by XRD, UV-VIS and PL spectroscopy. XRD shows the dominant wurtzite structure along with the oxide trace. Oxidation broadens the absorption edges and lowers the band gaps. PL spectra show near band gap emissions in the range 418 nm-421 nm along with the additional impurity emissions around 462 nm, 488 nm & 532 nm. These impurity emissions may be attributed to inherent defects on the surface that can emit band-trap emissions.

Million tons of coals are being burned every year to meet the electric power requirement in India. Fly ash powder, a by-product recovered from the gases of burning pulverized coal in thermal power plants contains alumina, silica, iron oxide and other heavy metals as well and cause air, soil and water pollution. So, in this present study, attempt have been made to investigate the potential utilization of fly ash collected from north eastern region of India to make some valuable products which will be used in construction industry. Authors have adapted a green technology i.e. geopolymerization technology for making the same. Geopolymerization process is associated with the alkali activation of materials which are rich in amorphous alumino-silicate. In this present investigation, sodium hydroxide is used as an alkaline activator for the dissolution of fly ash powder. The geopolymerization process has been performed using 8 M, 10 M and 12 M sodium hydroxide solution cured under artificial conditions. The mechanical property (compressive strength) was determined by using compression testing machine. Further, the strength data of the geopolymeric samples were co related with the results obtained from various characterization techniques such as scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR).

Energy is of vital importance to the society and human life. The world is entering into a period of declining non-renewable energy resources. Bio-diesel seems to be a good remedy for this problem. Microalgae is a potential source for the continuous production of biodiesel. Moreover, the productivity of biodiesel from microalgae is much higher compared to other sources of biodiesel. The present study deals with the performance characteristic of the Algae biodiesel run diesel engine. For analysis, two biodiesel blends namely, B10 and B20 (10 % and 20 % algae oil respectively mixed with diesel) were selected. The study revealed that with increasing engine load, the brake thermal efficiency was enhanced for B10 blend compared to diesel. For 75 % load, the brake thermal efficiency of B10 blend was found to be around 21.8 %. Moreover, the brake specific fuel consumption of B10 blend was observed to be very less as compared to diesel and B20 blend. In addition, at 75 % load, the mechanical efficiency of B10 blend was found to be around 37.7 %.

TiO2 has been shown to be excellent photoactive material in the presence of UV light. In order to make TiO2 a more efficient photocatalyst several attempts are being made. The present work attempts to address the issue through WO3-TiO2 (TW sample) and Nb2O5-TiO2 (TN sample) composites. Both the composite were synthesized through sol-gel process. The composites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV–Visible spectrophotometer. The composites lower band gap value than DP25. This effect also seems to be reflected in photo-degradation experiment. Photo-degradation of methylene blue (MB) dye, in the presence of Nb2O5-TiO2, WO3–TiO2 composite and DP25 under UV irradiation was studied. WO3–TiO2 composites have superior photoactivity than Degussa P25 (DP25) while Nb2O5-TiO2 composite seems to have deteriorating effect on photoactivity of TiO2.

The present work focuses on the systematic study of the removal of diary industrial pollutants from effluent of MILMA – Kerala Co-operative Milk marketing Federation limited, Calicut through electrocoagulation process (EC). An electrocoagulation batch reactor with aluminium as anode and mild steel as cathode were designed and used for the treatment process. Optimization of various operating parameters such as operating time, pH and current Density on COD and Turbidity removal were studied. The results indicates that the operating time and the applied current density has a positive relationship with the removal efficiency. Higher removal efficiency was found at neutral to alkaline region pH of 7 to 9. Over 95.00 % of pollutants removal efficiently was observed by conducting the EC treatment at current density (CD) of 33.33 A/m2, pH of 7 and EC time of 75 min. The effect of multielectrode system was studied with the obtained optimized parameters in which Monopolar and Bipolar configurations were tested. Out of which Monopolar configuration was found to be most effective in reduction of COD.

The Polycrystalline ceramic samples with formula unit Bi2V1-xTix/2Alx/2O5.5-d (x = 0.1 and 0.175) were synthesized. The specimens were characterized by AC Impedance Spectroscopy for dielectric studies. The variation of dielectric parameters: dielectric constant ( ), dielectric loss (tan ), complex electric modulus and AC conductivity, as a function of frequency and temperature, have been analyzed. The dielectric loss peaks and AC conductivity plots revealed different relaxation mechanisms i.e. electrode-electrolyte, conduction and dipolar occurring at low, intermediate and high-frequency regimes respectively. The shifting of the dielectric relaxation peaks and hopping frequency in AC conductivity plots towards higher frequency sides with an increase in temperature imply these materials are ionic conductor.

Effects of sintering temperature on structural and electrical properties of La2Mo2O9 synthesized via solution combustion method are addressed in this work. Single phase of La2Mo2O9 was obtained at relatively lower calcination temperature (700 oC) than the conventional route. The synthesized specimen was sintered at three different temperatures 800 oC, 900 oC and 1000 oC for 12 hours and was subjected to structural & electrical characterizations. X-Ray diffraction pattern confirms the formation of monoclinic phase with space group P213 for all three sintering temperatures. Lattice parameters were calculated using Reitveld technique and found to be increased with the sintering temperature. a ß phase transition is prominent in the Arrhenius plot of all the sintered samples but the transition temperature is lower than the powders obtained by the solid state technique. Conductivity was found to be increased slightly at lower and intermediate temperatures for 900 oC and 1000 oC as compared to specimen sintered at 800 oC. In the intermediate temperatures, grain boundary contribution to the total resistance is more distinguished in the Nyquist plot of the sample sintered at 800 oC which causes the decrement in the conductivity. Activation energy in the temperature range 600 - 750 oC for the sample sintered at 800 oC, 900 oC and 1000 oC are 0.5298 eV, 0.35896 eV and 0.35805 eV respectively. The sample sintered at 1000 oC exhibited highest ionic conductivity 0.0391 S.cm-1 at 750 oC.

Quantum Dots Sensitized Solar Cell (QDSSC) recently has become a potential source to provide an alternate way to harvest the solar light for the energy conservation. Since the quantum confinement effect of the QDs result in unique optoelectronic properties of the metamaterials, it is playing an important role in designing of smart photodetectors, light-emitting diodes and solar cell in the recent years. The semiconductor materials (chalcogenides) have gained a significant ground for the fabrication of QDSSC. The main advantage is their large industrial production with tunable band gap, which helps in fabrication of cost-effective, but, high performance QDSSC devices. The efficiency of QDSSCs depends upon the fabrication method of QDs, which refines the morphology and physicochemical properties of the desired material. Thus, it is important to engineer the QDs in such a way, so that after optimization of fabrication method, they can be used for the improvement of QDSSC performances. Although large variety of solar cell technologies are being developed, which also include dye sensitized nano crystalline solar cells, depleted heterojunction solar cells, hybrid organic-inorganic solar cells and bulk heterojuncion solar cells. However, the recent focus is on the fabrication of QDSSC, where the dye is replaced by nano sized inorganic particle that enhances the performance of QDSSC.

The present work reports on fabrication and electrochemical evaluation of LiFePO4/C based composite electrode for lithium ion battery using aqueous medium with carboxymethyl cellulose and citric acid as biomass derived sustainable binder materials. The composite electrode was prepared by dispersing the LiFePO4/C and acetylene black powders in aqueous suspension of carboxymethyl cellulose and citric acid with fractional weight ratio of 80:10:10 (w/w %). The carboxymethyl cellulose with citric acid additive significantly improved the cyclic performance of the composite cathode with specific capacity of 85 mAhg-1 and 65 mAhg-1 at 4 C and 5 C-rates respectively and good capacity retention with 100 mAhg-1 after 50 cycles at 1 C discharge rate. The improved performance was attributed to good adhesion and excellent dispersion of particles within the composite electrode. This work demonstrated that switching to water based production process could reduce the manufacturing cost significantly with additional advantage of safety, performance, and more importantly environmental benign electrodes for lithium ion battery.

It is necessary to optimize the process parameters for multi-walled carbon nanotubes (MWCNTs) synthesis to get better yield. This needs to be done for each precursor type used for the synthesis of MWCNTs. To achieve the twin objective of physical optimization of the process parameters for better yield for each precursor type poses almost an impossible task because of time and cost involved in the process. However, statistical technique such as Taguchi robust method is expected to be an efficient and effective tool to do this. The process needs to be optimized for each of the precursors selected for MWCNT synthesis for higher yield and acceptable relative quality conforming to requirement of applications. In the present work, a few parameters such as temperature, catalyst and flow rate that influence the yield and quality of MWCNT synthesized from three green precursors viz. Azadirachta indica, Sesamum indica and Mesua ferrea essential oil have been identified.

The present paper reports the synthesis and characterization of mixed halide based formamidinium lead Perovskite nanoparticles having general formula [HC(NH2)2]PbInBr3-n. A single step low temperature chemical route using microwave reactor is reported. The Perovskites synthesized were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). The X-ray diffraction revealed phase purity and tetragonal structure whereas TEM micrographs found that the synthesized particles are at 10-12 nm, 12-15 nm, 15- 20 nm and 20-22 nm for FAPbI3, FAPbBr3, FAPbBrI2 and FAPbIBr2 respectively. Optical properties and molecular bonding of the Perovskites was investigated by Fourier transform infra-red spectroscopy.