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Selected AbstractsA Combined Hydroxylation of 3-Cyanopyridine to 3-Cyano-6-hydroxypyridine and 6-Hydroxynicotinic Acid by Resting Cells of Comamonas testosteroni JA1 Grown on Nicotinic AcidENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2005S. Yuan Abstract A strain of Comamonas testosteroni,JA1 known for its capacity to hydroxylate 3-cyanopyridine to 3-cyano-6-hydroxypyridine was found to be also capable to hydroxylate nicotinic acid at a higher rate. In the course of the induced cultivation the forming 6-hydroxynicotinic acid was degraded either slightly, in the presence of nicotinic acid in the medium, or faster, in the absence of nicotinic acid. In a combined process of hydroxylation of nicotinic acid by growing culture and hydroxylation of 3-cyanopyridine by resting cells of Comamonas testosteroni,JA1, not only an additional amount of 50.38,g of solid 6-hydroxynicotinic acid was produced from 1,L of cultivation broth with a 99.97,% molar conversion yield, but also the yield of 3-cyano-6-hydroxypyridine produced was more than doubled. This can be compared to that of the resting cells from the induced cultivation broth where within 8,h an amount of 5.77,g of solid 3-cyano-6-hydroxypyridine was produced by resting cells from 1,L of the cultivation broth. This also was superior to 4.39,g/L of cultivation broth of resting cells reported in the literature. [source] Inorganic sulphate extraction from SO2 -impacted AndosolsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2005T. Delfosse Summary Sulphate sorption on to the surface of short-range ordered minerals and precipitation of Al-hydroxy sulphate contribute to the acid neutralizing capacity of soils. The correct measurement of total inorganic sulphate is thus essential in soils that are accumulating SO42, anions. We extracted SO42, by various solutions, namely 0.005 m Ca(NO3)2, 0.016 m KH2PO4, 0.5 m NH4F and 0.2 m acidic NH4 -oxalate (pH 3), from Vitric and Eutric Andosols exposed to prolonged deposition of acid and SO2 from an active volcano (Masaya, Nicaragua). We attributed sulphate extractable by KH2PO4 (20,3030 mg kg,1) to anion-exchangeable SO42,, which was much smaller than NH4F- and oxalate-extractable SO42, (400,9680 and 410,10 480 mg kg,1, respectively). Our results suggest the occurrence of a sparingly soluble Al-hydroxy-mineral phase extractable by both NH4F and oxalate. The formation of Al-hydroxy minerals would result from the combination of enhanced weathering caused by strong acid loading and simultaneous occurrence of large SO42, concentrations in soil solution. Oxalate extracted slightly more inorganic SO42, than did NH4F, this additional amount of SO42, correlating strongly with oxalate-extractable Si and Fe contents. Preferential occlusion of SO42, by short-range ordered minerals, especially ferrihydrite, explains this behaviour. If we exclude the contribution of occluded sulphate then oxalate and NH4F mobilize similar amounts of SO42, and are believed to mobilize all of the inorganic SO42, pool. [source] RESERVOIR OPERATION ANI EVALUATION OF DOWNSTREAM FLOW AUGMENTATION,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2001Mahesh Kumar Sahu ABSTRACT: Operation of a storage-based reservoir modifies the downstream flow usually to a value higher than that of natural flow in dry season. This could be important for irrigation, water supply, or power production as it is like an additional downstream benefit without any additional investment. This study addresses the operation of two proposed reservoirs and the downstream flow augmentation at an irrigation project located at the outlet of the Gandaki River basin in Nepal. The optimal operating policies of the reservoirs were determined using a Stochastic Dynamic Programming (SDP) model considering the maximization of power production. The modified flows downstream of the reservoirs were simulated by a simulation model using the optimal operating policy (for power maximization) and a synthetic long-term inflow series. Comparing the existing flow (flow in river without reservoir operation) and the modified flow (flow after reservoir operation) at the irrigation project, the additional amount of flow was calculated. The reliability analysis indicated that the supply of irrigation could be increased by 25 to 100 percent of the existing supply over the dry season (January to April) with a reliability of more than 80 percent. [source] Rubber toughening of glass fiber reinforced nylon-6,6 with functionalized block copolymer SEBS-g-MAADVANCES IN POLYMER TECHNOLOGY, Issue 3 2002George P. Karayannidis Abstract The toughening of glass fiber reinforced nylon-6,6 (PA-6,6) by using the functionalized triblock copolymer styrene-(ethylene-co-butylene)-styrene, grafted with maleic anhydride (SEBS-g-MA) was examined. Blends containing 2.5, 5, 7.5, 10, and 12.5 wt% copolymer were prepared by melt blending in a single-screw extruder. Emphasis was given to the study of mechanical properties in comparison with morphology and thermal properties of the aforementioned samples. Although the amount of SEBS-g-MA that was added in PA-6,6 was not enough to produce a super-tough material, a significant increase in the resistance to crack propagation and impact strength was observed in all blends. This behavior was proportional to the amount of SEBS-g-MA that was added for samples having up to 10%, rubber, while additional amounts seem to have no further effect. A small decrease in tensile strength was also observed. From FTIR spectroscopy and DSC analysis it was shown that the grafting extent of SEBS-g-MA to PA-6,6 was very low. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 153,163, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/adv.10023 [source] Application of continual injection liquid-phase microextraction method coupled with liquid chromatography to the analysis of organophosphorus pesticidesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 4 2009Yanuardi Raharjo Abstract A liquid-phase microextraction coupled with LC method has been developed for the determination of organophosphorus pesticides (methidation, quinalphos and profenofos) in drinking water samples. In this method, a small amount (3 ,L) of isooctane as the acceptor phase was introduced continually to fill-up the channel of a 1.5 cm polypropylene hollow fiber using a microsyringe while the hollow fiber was immersed in an aqueous donor solution. A portion of the acceptor phase (ca. 0.4 ,L) was first introduced into the hollow fiber and additional amounts (ca. 0.2 ,L) of the acceptor phase were introduced to replenish at intervals of 3 min until set end of extraction (40 min). After extraction, the acceptor phase was withdrawn and transferred into a 2 mL vial for a drying step prior to injection into a LC system. Parameters that affect the extraction efficiency were studied including the organic solvent, length of fiber, volume of acceptor and donor phase, stirring rate, extraction time, and effect of salting out. The proposed method provided good enrichment factors of up to 189.50, with RSD ranging from 0.10 to 0.29%, analyte recoveries of over 79.80% and good linearity ranging from 10.0 to 1.25 mg/L. The LOD ranged from 2.86 to 82.66 ,g/L. This method was applied successfully to the determination of organophosphorus pesticides in selected drinking water samples. [source] | ||||||||||