NOPR Collection:

An oxidative route to nitrogen fixatiop: Surface bound oxygen atom transfer to coordinated nitrogen in K[Ru(EDTAH)N2] by UV irradiation of Pt/TiO2/RuO2 suspension in aqueous solution and formation of N2O, NO, NO2 and NO

1989-07-01T00:00:00Z

Title: An oxidative route to nitrogen fixatiop: Surface bound oxygen atom transfer to coordinated nitrogen in K[Ru(EDTAH)N2] by UV irradiation of Pt/TiO2/RuO2 suspension in aqueous solution and formation of N2O, NO, NO2 and NO Authors: Khan, M M Taqui; Rao, N Nageswara Abstract: An aqueous solution containing 1 x 10^-3 M K[Ru(EDTAH)Cl^].2H₂O and the catalyst Pt/TiO₂(ana-tase)/RuO₂, on irradiation at 390 nm under a current of nitrogen produces nitrogen oxides and nitrate along with H₂ and O₂. The formation of these products has been substantiated. Page(s): 543-544

Quenching of excited states of oxytetracycline and phenol by amino acids: An intermolecular proton donor-acceptor interaction

1989-07-01T00:00:00Z

Title: Quenching of excited states of oxytetracycline and phenol by amino acids: An intermolecular proton donor-acceptor interaction Authors: Roy, R; Mukherjee, S Abstract: Fluorescence quenching of oxytetracycline and phenol by a number of amino acids has been studied in alkaline and neutral medium respectively. Quenching is assumed to involve an intermolecular H-bond interaction between the colliding species in the excited state, involving OH of phenol or oxytetracycline and carboxylate ion of the amino acids. The observed anomalous increase in the quenching of oxytetracycline fluorescence, which appears as positive deviation from Stern-Volmer plots is discussed. A proton transfer reaction is assumed to be involved due to the occurrence of a stronger H-bond in the case of oxytetracycline fluorescence quenching. However, linear Stern-Volmer plots are obtained in the case of phenol fluorescence quenching by all the amino acids under study and bimolecular rate constants obtained are found to be similar to the rate constant for the diffusional process. Page(s): 545-549

Phase behaviour and physicochemical properties of triton X 100 and aerosol OT induced micro emulsions of hydrocarbons and water in presence of n-butanol

1989-07-01T00:00:00Z

Title: Phase behaviour and physicochemical properties of triton X 100 and aerosol OT induced micro emulsions of hydrocarbons and water in presence of n-butanol Authors: Bisal, S R; Bhattacharya, P K; MouIik, S P Abstract: Phase diagrams of microemulsions composed of water/ oil/ AOT/ n-butanol and water/ oil/TX 100/n-butanol are presented. The oils used are: n-hexane, n-heptane, n-octane and n-decane. Small lamellar zones appear with AOT along with large isotropic microemulsion areas. The 1:1 (wt/wt) ratio of surfactant- cosurfactant produces appreciable microemulsion area. At constant surfactant-cosurfactant ratio, the microemulsion areas decrease with the chain length of the alkanes. The minimum percentage of AOT required for dissolving about 40-50 wt % of water in hexane is - 8 wt %, which increases from 8-15 wt % for heptane, octane and decane. TX 100 imparts less microemulsion area than AOT with increase in alkane chain length. The conductances, viscosities, specific volumes and compressibilities of both the microemulsion systems at 1:1 (wt/wt) surfactant-cosurfactant ratio have been determined within no-water-to-no-oil limit. The-viseosity is maximum-at -31 vol % water. The conductance-sharplyin creases after addition of 0 01 % water. Both the specific volumes and the compressibilities decrease with increase in water content. The microemulsions become more compact with increase in water content; the ion conductance increases due to the combined effects of increased dielectric constant and channel formation. A comparison among the hydrocarbons on the basis of Walden product (λη), the product of specific volume and the compressibility (vβ^-1), the excess specific volume (v_ex) and the excess compressibility (β_ex) at different stages of water addition, shows that the viscosities and conductances of AOT based systems compensate each other at low and high percentages of water and not in the intermediate range. The vβ^-1 and v_ex values for both the AOT and TX 100 based systems suggest swelled microemulsions with increase in alkane chain length, particularly at lower percentages of water; these even out at higher water levels. The internal degree of flexibility is more for AOT based than that for TX 100 based microemulsions. Page(s): 550-556

Electrosynthesis and photoelectrochemical characterization of zinc selenide doped with thallium

1989-06-01T00:00:00Z

Title: Electrosynthesis and photoelectrochemical characterization of zinc selenide doped with thallium Authors: Singh, K; Rai, J P Abstract: Thallium-doped zinc selenide semiconductor electrode has been prepared by electrochemical code-position: Such doped electrodes exhibit photoresponsiveness significantly higher than that of zinc selenide electrodeposits prepared and tested under similar experimental conditions. Capacitance measurements and current-voltage behaviour in dark and under illumination in conjunction with photoaction spectral studies have been used for the characterization of Tl-doped zinc selenide electrode. The results indicate that incorporation of thallium modifies zinc selenide characteristics so as to enable it to exhibit improved photoelectro-convertibility. Page(s): 557-560