National College, Tiruchirappali

The study emphasis the effect of elevated temperature on concrete cubes made with M20, M25, and M30 concrete grades. The other variables considered were temperature (100, 200, 400, and 600 °C), duration of exposure (1-h and 2-h) and two types of cooling methods. The mass loss is varied from 0.52 to 6.56% for various temperature and duration of exposure. The mass loss increases as the duration of exposure increased. The porosity ranges from 9.89 to 44.34% and it depends on grade of concrete and exposed temperature. The strength loss ranges from 3% at 200 °C to 57% at 600 °C for air cooled specimen. In quench cooled specimen the loss in strength varies gradually up to 200 °C but at 400 °C the loss in strength was 42%, while the loss was only 32% for air cooled specimen. The obtained residual compressive strength curve from this study was compared with strength curves proposed by various codes.

Biodiesel fuel (BDF) produced by alcoholysis of vegetable oils or fats is viewed as a promising renewable fuel source. Diminishing petroleum reserves and increasing environmental regulations have made the search for renewable fuel. Biodiesel is non-toxic and biodegradable, produced from renewable sources and contributes a minimal amount of net green-house gases, such as CO 2, SO 2 and NO emissions to the atmosphere. The main objective of the present study is to produce biodiesel from vegetable oil and to use micro-emulsions with solvents ethanol and methanol following acid, alkali and fungal enzyme catalysis methods. The best suited method of biodiesel production was ethanolic and alkali mediated trans-esterification process rather than methanolic and acidic trans-esterification. The maximum yield of biodiesel was obtained from Rhizopus oryzae lipase enzyme, ethanolic and alkali mediated trans-esterification followed by Aspergillus niger, Polyporus squamosus and Agaricus campestris.

In the title compound, C11H9ClN4OS2, the thia­diazole and chloro­phenyl rings are oriented at an angle of 43.1 (1)°. The sum of the bond angles around the amide N atom (359.8°) of the acetohydrazide group is in accordance with a model of sp² hybridization. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R2²(8) loops. Weak C—H⋯π inter­actions also occur.

This paper reports the rehabilitation of the historic St. Lourdes Church in Tiruchirappalli, India. The structure is a critical landmark and a significant representation of religious buildings in the area. Inspections of the Gothic style masonry church were completed in 1998, where distress and decay due to water damages were identified and repaired using lime-based materials. A subsequent inspection 10 years later indicated that remains a critical issue. This case study demonstrates the importance of rehabilitation of historic structures using appropriate construction techniques including possible alternative rehabilitation approaches to ensure the preservation of these structures.

In the title compound, C33H34N6O6, the dihydrobenzimidazol-2-one ring system is essentially planar (r.m.s. deviation = 0.021 Å). The cyclohexane ring adopts a chair conformation. In the 5-(biphenyl-2-yl)-2H-tetrazole fragment, the tetrazole ring is twisted away from the attached benzene ring by 35.73 (11)° and the two benzene rings form a dihedral angle of 68.00 (9)°. An intramolecular C—H...O interaction is observed. In the crystal, the molecules are linked into a zigzag chain running along the b axis by intermolecular N—H...O hydrogen bonds.

In the title compound, C33H34N6O6, the dihydro­benzimidazol-2-one ring system is essentially planar (r.m.s. deviation = 0.021 Å). The cyclo­hexane ring adopts a chair conformation. In the 5-(biphenyl-2-yl)-2H-tetra­zole fragment, the tetra­zole ring is twisted away from the attached benzene ring by 35.73 (11)° and the two benzene rings form a dihedral angle of 68.00 (9)°. An intra­molecular C—H⋯O inter­action is observed. In the crystal, the mol­ecules are linked into a zigzag chain running along the b axis by inter­molecular N—H⋯O hydrogen bonds.

The focus of this study is identification, isolation and characterization of a principal oxidation impurity of clopidogrel which ranged from 0.05 to 0.12% using high performance liquid chromatography. This impurity is considered as principal oxidation impurity as it is observed in oxidative degradation (stress) study. Preparative HPLC with Xterra MS C18 ODB column was used to isolate the impurity. The isolated impurity was co-injected with the sample containing impurities and found the retention time match of the spiked impurities. A thorough study was undertaken to characterize this impurity and based on their spectral data (UV, MS, MSn 1H/13C, DEPT and 2D NMR) the structure was characterized as 5-[1-(2-chlorophenyl)-2-methoxy-2-oxoethyl]-6,7-dihydrothieno[3,2-c]pyridin-5-ium with a molecular weight 320 amu.

Porous carbon electrodes containing platinum and platinum-ruthenium catalysts are prepared by a rolling technique with polytetrafluoroethylene as a binder. The 5 and 10 wt.% of the catalyst is deposited on a carbon substrate (Vulcan XC-72) by a colloidal dispersion technique. Half-cell polarization studies in 2.50 M H2SO4 electrolyte containing CH3OH (1.0–3.0 M) have been carried out. The polarization values of electrodes containing platinum-ruthenium are lower than that of catalysts containing platinum only. Porous electrodes containing 2–5.0 mg cm−2 of catalyst exhibit a polarization value of less than 300 mV at 100 mA cm−2 at 60 °C in 2.50 M H2SO4.

Kirkwood-Fröhlich's linear correlation factor of dielectric polarisation of propan-2-ol, butan-1-ol, 3-methylbutan-1-ol and phenyl carbinol in solutions with cyclohexane, carbon tetrachloride and benzene as solvents which gives clue on the dipole orientation of the molecular aggregates of the alcohols is reported. The kinetic process responsible for the dielectric behaviour of these alcohols is analysed on the basis of significant structure model of associated liquids. Eyring's interaction parameterG * is influenced by the nature of the solvent and has been interpreted with regard to the changes in the dipole interaction of the solute domains in the solvent environment.