NOPR Collection:

Comparison of Fixation Characteristics of New Acid Fixing Reactive Dyes Derived from 5,10 -Phenophosphazine Ring with Commercial Reactive Dyes on Nylon 66 and Wool Substrates

Sun, 01 Sep 2002 00:00:00 GMT

Title: Comparison of Fixation Characteristics of New Acid Fixing Reactive Dyes Derived from 5,10 -Phenophosphazine Ring with Commercial Reactive Dyes on Nylon 66 and Wool Substrates Authors: Mamuda, A; Bello, K A; Yakubu, M K Abstract: The traditional alkaline reactive dyes were found unsuitable for the continuous dyeing of the polyester/cotton blends. This and other problems lead to the search for the acid fixing reactive dyes. Calcobond and Procion T dyes were thus introduced. However, these series of dyes have suffered diminishing acceptability because of the expensive application conditions. Dyes derived from the 5,10- phenophosphazine ring were accidentally found to form covalent bonds with cellulose at neutral pH earlier. This report ex tends application of these groups of dyes to wool and nylon substrates. The effect of pH on exhaustion and fixation was investigated. The kinetics of dyeing was also studied and compared with some commercial alkaline fixing reactive dyes. The dyes have been established to be acid fixing on wool and nylon. A reaction mechanism has also been proposed. Page(s): 729-733

A Low Cost Device for Production of Country Roofing Tiles

Sun, 01 Sep 2002 00:00:00 GMT

Title: A Low Cost Device for Production of Country Roofing Tiles Authors: Handa, S K; Verma, C L Abstract: Country roofing tiles, are extensively used in the villages as roofing material. The conventional production technique used for producing tiles is through potter wheel or by manual moulding technique. These processes yield non-uniform, uncompacted, dimensionally unstable and poor quality products. The tiles generally depict considerable damage or breakage during transportation or fixing in a roof. In view of this, a low cost moulding device for production of compact country roofing tiles was designed and fabricated in Central Building Research Institute (CBRI ), Roorkee. Extensive trials have proven its amenability to commercialization for production rate of 500-600 tile s/d by a semi-skilled worker. The details of the low cost device for production of country roofing tiles have been delineated. Use of this device will certainly generate employment in the rural areas of India and other developing countries. Page(s): 726-728

Chemical and Biochemical Degradation of Waste Cellulosic Materials

Sun, 01 Sep 2002 00:00:00 GMT

Title: Chemical and Biochemical Degradation of Waste Cellulosic Materials Authors: El-Masry, A M; Ghaly, M F; Khalafallah, M A; EI-Fayed, Y A Abstract: Some of the agricultural wastes such as, pith bagasse, rice husk and corn maize are subjected to both chemical and biochemical degradation. Different acid concentrations as well as cellulase-producing microorganisms are tested. Comparative studies between the chemical hydrolysis and enzymatic degradation, for the selected cellulosic materials, are discussed. Cellulase(s) enzyme activity. 50.25µg/mL is obtained (pH 5.5 using 2g/L carbon source) in shaking culture. Results indicate that the optimum cone, of HCI, which gives the highest yield of reducing sugars from the used cellulose materials is 5 per cent. Byproducts formed by acid degradation and enzymatic hydrolysis reveal that the residue of chemical hydrolysis is the most appropriate substrate for enzyme degradation rather than the raw materials. Screening of cellulase producing-organisms in the soil, show that actinomycetes and fungi are predominant. The most efficient fungal isolate is identified as Aspergillus ochraceous. Occurrence of free reducing sugars in the growth medium as well as prolonged incubation times. both drastically affect cellulase(s) yield. Reduction in sugar content and cellulose remaining are inversely proportional. Page(s): 719-725

Surface Parameters and Corrosion Inhibition of Some Isothiouranium Derivatives

Sun, 01 Sep 2002 00:00:00 GMT

Title: Surface Parameters and Corrosion Inhibition of Some Isothiouranium Derivatives Authors: Keera, S T; Negm, N A; Ahmed, S M; Badawi, A M Abstract: Four alkyl isothiouronium halide compounds in which the alkyl groups are dodecyl, hexadecyl, and octadecyl, respectively, are prepared. The measured surface tension at various concentrations as aqueous solutions of each of these compounds at various temperatures enable the calculation of surface and thermodynamic parameters. The critical micelle concentrations of these compounds decreases with increase in temperature. The calculated free energy changes for micelle formation and ad sorption of these compounds shows that these processes are spontaneous in nature. The corrosion inhibition properties of these compounds for mild steel in sulphuric acid as determined through potentiodynamic polarization measurements, indicates that dodecyl isothiouronium bromide exhibits better inhibitor efficiency than its higher homologues. For the same compound studied, the iodide salt gives a better inhibitor efficiency than the bromide. Page(s): 712-718