2017Publications of year 2017http://localhost:8080/xmlui/handle/123456789/26872024-03-28T23:47:07Z2024-03-28T23:47:07ZStudies on Tensile Behaviour and Microstructural Evolution of UFG Mg-4Zn-4Gd Alloy Processed Through Hot RollingVerma, RSrinivasan, AJayaganthan, RNath, S KGoel, Shttp://localhost:8080/xmlui/handle/123456789/32842018-11-07T10:33:20Z2017-09-17T00:00:00ZStudies on Tensile Behaviour and Microstructural Evolution of UFG Mg-4Zn-4Gd Alloy Processed Through Hot Rolling
Verma, R; Srinivasan, A; Jayaganthan, R; Nath, S K; Goel, S
The effect of rolling at elevated temperature on mechanical behaviour of bulk Mg-4Zn-4Gd alloy was investigated. The alloy was subjected to solution treatment at 673 K for 24 h, followed by flat and cross rolling at elevated temperature (723 K). The microstructure of ultrafine grains (less than ~1 μm size) was successfully
achieved from solutionized sample with grain size ~78 μm after the rolling process, which has significantly
influenced the mechanical behaviour of the deformed Mg alloy. The yield strength (YS), ultimate tensile strength (UTS), elongation-to-failure (%E) and hardness of a rolled specimen have enhanced maximum up to the value of 276.3±13 MPa, 341.3±7 MPa, ~26.1% and 74.2±2 HV, respectively. The improvement in mechanical properties of processed Mg alloys due to the combined effect of grain refinement and secondary phase (W-phase) distribution into the Mg matrix upon the repetitive rolling process. In addition, the improvement in tensile properties is explained by correlating the dislocation density (ρ), scanning electron (SEM) and transmission electron (TEM) micrographs. The developed intrinsic property of rolled specimens is substantiated by tensile fractography obtained from SEM equipped with energy dispersive X-ray spectroscopy (EDS). Various other microstructural features were also revealed by TEM and X-ray diffraction (XRD) analysis. The anisotropy of various rolled Mg-4Zn-4Gd specimens was also elucidated on the basis of tensile results.
2017-09-17T00:00:00ZStibnite Sensitized Hollow Cubic TiO2 Photoelectrodes for Organic-Inorganic Heterojunction Solar CellsGanapathy, VZhang, KSuraj SomanNansra, HPark, J Hhttp://localhost:8080/xmlui/handle/123456789/32832018-10-29T15:45:40Z2017-11-15T00:00:00ZStibnite Sensitized Hollow Cubic TiO2 Photoelectrodes for Organic-Inorganic Heterojunction Solar Cells
Ganapathy, V; Zhang, K; Suraj Soman; Nansra, H; Park, J H
Enhancing power conversion efficiency in organic-inorganic heterojunction solar cells faces several serious
hurdles. Although standard TiO2 nanoparticles-based heterojunction solar cells are moderately efficient, the
TiO2 nanostructure has several drawbacks including a disordered low surface area with poor pore structure.
Thus, it is necessary to develop a new TiO2 morphology for effective photon harvesting in organic-inorganic
heterojunction solar cells. Hollow nanostructured electrodes are widely used in energy related devices because of their high surface area, larger pores, and superior light scattering properties. Here, we report the first successful application of hollow cubic TiO2 (HCT) nanostructured photoelectrodes sensitized with stibnite for all solid-state heterojunction solar cells. The unique hollow nanostructure resolved several issues of organic-inorganic heterojunction solar cells, such as insufficient pore size for inorganic sensitizers, large grain boundary area, and poor penetration of organic hole conductors, thereby improving the cell efficiency. Device performance was strongly dependent on the thickness of stibnite, which could be controlled by deposition time. Devices optimized with HCT exhibited a high solar to power conversion efficiency (∼3.5%), which was slightly higher than the TiO2 nanoparticle-based devices.
2017-11-15T00:00:00ZSelf-Cycling Fermentation for 1,3-Propanediol Production: Comparative Evaluation of Metabolite Flux in Cell Recycling, Simple Batch and Continuous Processes Using Lactobacillus Brevis N1E9.3.3 StrainVivek, NAswathi, T VSven, P RPandey, ABinod, Phttp://localhost:8080/xmlui/handle/123456789/32792018-10-25T09:51:46Z2017-10-10T00:00:00ZSelf-Cycling Fermentation for 1,3-Propanediol Production: Comparative Evaluation of Metabolite Flux in Cell Recycling, Simple Batch and Continuous Processes Using Lactobacillus Brevis N1E9.3.3 Strain
Vivek, N; Aswathi, T V; Sven, P R; Pandey, A; Binod, P
The microbial conversion of biodiesel derived crude glycerol to 1,3-propanediol (1,3-PDO) has attained high
industrial value due to the broad range of applications as a monomer (1,3-PDO) in textile, cosmetic and polymer industries. This fine chemical through biological production addressed several limitations of the chemical process like high temperatures, pressure and expensive catalysts. In this study 1,3-propanediol production was achieved from a non-pathogenic lactic acid bacterial strain Lactobacillus brevis N1E9.3.3 in suspended and immobilized form under batch, sequential batch and continuous modes of fermentation. The microorganism was immobilized in polyurethane foam cubes. The effects of initial glycerol concentration on suspended and immobilized cells were investigated in stirred tank reactor. The maximum 1,3-PDO titers of 51.5 g1,3-PDO/l and 42.59 g1,3-PDO/l with a yield of 0.64 g1.3-PDO/gGlycerol and 0.53 g1.3-PDO/gGlycerol using suspended and immobilized cells respectively was observed in batch fermentation with an initial glycerol concentration of 80 g/l. In repeated batch (self-cycling) fermentation 78.3 g/l 1,3-PDO with 0.65 g1.3 PDO/gGlycerol yield and 0.65 g/l/h productivity was observed at the end of 5th cycle. A constant yield between 0.3–0.65 g1.3-PDO/gGlycerol was observed with cell recycling using suspended and immobilized cells. The highest productivity of 1.735 g1,3-PDO/ l/h was observed in chemostat with immobilized cells.
2017-10-10T00:00:00ZSelf-assembly of Anacardic Acid Derived Cation-Modified Montmorillonite into ’Arthropodal’ Branched NanofibersChacko, A SPrasad, V Shttp://localhost:8080/xmlui/handle/123456789/32782018-10-25T09:44:55Z2017-02-20T00:00:00ZSelf-assembly of Anacardic Acid Derived Cation-Modified Montmorillonite into ’Arthropodal’ Branched Nanofibers
Chacko, A S; Prasad, V S
Montmorillonite (MMT) was organo-modified with tri-(2- carboxy-3-pentadeca-8,11,14]-trienylphenoxy) aminopropylsilyl sulfate cation, synthesized from anacardic acid (AA), a biomonomer by cation exchange and characterized. The modified product (AAM) showed a decreased crystallinity with an increase in d-spacing of MMT from 1.47 nm to 2.29 nm attributed to intercalation by modification. AAM solution in the water-acetone mixture at 3.0 mg mL 1 showed an organization into ’arthropodal’ branched nanofibers of about 30–60 nm
diameter and 10–20 mm length. These results were attributed to rolling of AAM into grain like morphology stabilized by hydrogen bonded interactions induced by the carboxyl group and end to end assembly of the grains. Though acidic pH stabilized the morphology, an increase in pH to 8.0 marked the absence of any assembly attributed to lack of hydrogen bonding. The effect of the carboxyl group in the assembly was further established by the absence of any assembly in the case of MMT modified with cardanol, the decarboxylated product of AA. A simple strategy for the synthesis of biocompatible hybrid silicate nanofibers is demonstrated here.
2017-02-20T00:00:00Z