Magnetic and Transport Properties of Ternary Indides of type R2CoIn8 (R = Ce, Pr and Dy)

We have synthesized and investigated the magnetic and transport properties of a series of compounds, R2CoIn8 (R = rare earth). Compounds form in single phase with a tetragonal structure (space group P4/mmm, no. 162). The Ce compound shows heavy fermion behavior. The magnetic susceptibility of Pr2CoIn8 shows a marked deviation from the Curie-Weiss behavior at low temperatures, which is attributed to the crystalline electric field effects. Heat capacity and magnetization measurements show that Dy2CoIn8 undergoes a magnetic transition at 17 K and a second transition near 5 K, the latter of which may be due to spin reorientation. Magnetization of this compound shows two metamagnetic transitions approximately at 3.6 T and 8.3 T.Comment: Total 7 pages of text and figure

Design aspects and laboratory simulation study of a floating marine fish cage prototype with mooring system

In India, open sea cage culture has been successfully demonstrated and several experimental offshore cages for mariculture were installed along the coast for on-farm demonstration by the Central Marine Fisheries Research Institute, Cochin. In the present study, a model cage was fabricated and tested in a towing tank under different waves and current load conditions. The tension on the mooring chain was measured during the experimental study, besides the towing speed and wave parameters. Based on the experimental data, drag coefficient for the cage net twine was estimated. The tensions in the mooring chain and the cage net twine of the prototype cage were predicted based on the model data. The maximum tension on a single twine of the outer and inner fish net were estimated as 0.15 N and 0.028 N respectively. The force on the net was more than 1.7 times the force on the floating collar and sinker pipe. The tension in the mooring line is mainly due to the force on the net. Further it was observed that the force on the net due to current was 10 times higher than that due to wave. This information will be useful in future while deciding the diameter of the cage, the type of net to be used for cage according to the site where the cage is to be installed

Durability properties of fly ash and silica fume blended concrete for marine environment

1803-1812The improvement in durability and strength by replacing the conventional components with supplementary materials in concrete is one of the recently focused areas in concrete technology. From the previous till the recent times serious efforts have been taken to improve the structural adequacy and durability characteristics of concrete so as to efficiently replace the usual conventional concrete. In this present research work, the mechanical and durability properties of the concrete blended with fly ash (FC) and silica fume (SC) are studied in detail. The partial replacement of cement with silica fume and fly ash in the concrete improves the overall property of the concrete, gives a way for the reuse of the supplementary material to be efficiently brought back giving a cleaner environment. The fly ash is used with the replacement percentages of 10, 15 and 20 of the cement whereas for silica fume the replacement percentages are 8, 10 and 12, respectively. Also the study is extended to combination mixes to test the strength and durability and it has been found that the increase in the percentage of the silica fume increases the strength reduces the workability and permeability to a high extent and the inclusion of the fly ash paves a way for the increase in the durability property. The effect of the cementitious material with FC and SC on the concrete is compared with the nominal concrete and also the suitability in the usage of marine environment is validated in accordance with the International codes

Ayurveda and Epilepsy

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Nitroimidazoles: Part XVII. 5-Aminoimidazoles

2-Benzoyl-1-methyl-5-nitroimidazole (I) undergoes-reduction over Raney nickel catalysed to the amine (2), which is transformed into the p-chIorobenzamide (3), the acylthioureas (4 and 6) and the sulphonylthiourea (5). Alkaline hydrolysis of 4 affords the thiourea (7), Hydrogenation of the p-nitrobenzayl analogue (10) of 1 and condensation of the product with dimeihylformamide dimethylacetal leads to the bis-amidine (II). Catalytic reduction of the nitrosulphone (12) affords unstable 2-methanesulphonyl-1-methyI-S-aminoimidazole (13) forming stable acyl derivatives (14a-g) and thioureas U5a and 15b). Reaction of 13 with p-nitrobenzaldehydc furnishes in low yield an anomalous product considered to be 19, which probably results via the benzylidene-bisimidazole(16)and the tricyclic condensed pyridines(17and 18). 2-Meihunesulphinyl-1-metbyl-5-aminoimidazole arising from the nitro derivative (20a) is characterised as the acylthioureas (20b and 20c). Likewise the reduction product of 1-methylsulphonyl-3-(1-methyl-5-nitro-2-imidazoly])-2-irnidazolidinone (21a) has been isolated as the acetyl derivative (21b)

Enhancing the heat transfer of triangular pyramid solar still using phase change material as storage material

This paper presents the method of improvement of enhancing the performance of triangular pyramid solar still with and without latent heat energy storage. For comparing the productivity of solar still with and without LHTESS a solar still is designed, fabricated. Experiments are conducted in hot and humid climate of Chennai, India. Paraffin wax is used as LHTESS due to its feasible general and economic properties. The hourly productivity is slightly higher in case of solar still without LHTESS during sunny days. There is an increase of about 35% in production of fresh water with LHTESS than that of solar still without LHTESS. Also it was found that during the off shine period the fresh water produced from the still is higher. The solar still with and without LHTESS were found to be 4.5 L/m2day and 3.5 L/m2day

Investigation of novel high T<SUB>c</SUB> superconducting oxides

Our results of microscopic and macroscopic studies of novel high Tc superconductors are discussed. They permit a straightforward comparison of the nature of the superconductivity in 40 K range (La2CuO4 type) and 90 K range (YBa2Cu3O7type) superconductors