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Silicon - Thin film nanocomposites of sodium silicate (80 SiO2 –20 Na2O)/ tartrazine dye (E102) prepared using sol gel process in acidic system. The change in the physicochemical properties... 相似文献
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The corrosion behaviour of tin in different concentrations of citric acid solutions (0.3–1.0 M, pH=1.8) was studied at 30 °C by potentiodynamic technique. The E/I profiles exhibit an active passive behaviour. The active dissolution involves one anodic peak A associated with a dissolution of the metals as Sn(II) species. The passivity is due to the formation of thin film of SnO2 and or Sn(OH)4 on the anode surface. The cathodic sweep shows a small peak C related to the reduction of the passive film. The peak current density Ip of peak A increases with increasing both acid concentration and sweep rate.
The effects of adding increasing concentrations of Na2CrO4, NaMoO4, NaNO3 and NaNO2 on the corrosion of tin in 0.5 M citric acid at 30 °C were investigated. Both CrO42− and MoO42− ions inhibit the corrosion of tin and the extent of inhibition enhances with their concentrations. Addition of either NO3− or NO2− accelerates the corrosion of tin. NO3− ions are more aggressive than NO2− ions. 相似文献
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John D. Fitzsimons Bill Williston Georgina Williston Lisa Brown Abdel El-Shaarawi Lenore Vandenbyllaardt Dale Honeyfeld Don Tillitt Martha Wolgamood Scott B. Brown 《Journal of Great Lakes research》2007,33(1):93-103
Alewives (Alosa pseudoharengus), the major prey fish for Lake Ontario, contain thiaminase. They are associated with development of a thiamine deficiency in salmonines which greatly increases the potential for developing an early mortality syndrome (EMS). To assess the possible effects of thiamine deficiency on salmonine reproduction we measured egg thiamine concentrations for five species of Lake Ontario salmonines. From this we estimated the proportion of families susceptible to EMS based on whether they were below the ED20, the egg thiamine concentration associated with 20% mortality due to EMS. The ED20s were 1.52, 2.63, and 2.99 nmol/g egg for Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch), respectively. Based on the proportion of fish having egg thiamine concentrations falling below the ED20, the risk of developing EMS in Lake Ontario was highest for lake trout, followed by coho (O. kisutch), and Chinook salmon, with the least risk for rainbow trout (O. mykiss). For lake trout from western Lake Ontario, mean egg thiamine concentration showed significant annual variability during 1994 to 2003, when the proportion of lake trout at risk of developing EMS based on ED20 ranged between 77 and 100%. Variation in the annual mean egg thiamine concentration for western Lake Ontario lake trout was positively related (p < 0.001, r2 = 0.94) with indices of annual adult alewife biomass. While suggesting the possible involvement of density-dependent changes in alewives, the changes are small relative to egg thiamine concentrations when alewife are not part of the diet and are of insufficient magnitude to allow for natural reproduction by lake trout. 相似文献
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Nonionic organic contaminants such as phenol, benzene, and toluene from contaminated wastewater on laboratory scale can be effectively sorbed by cellulosic wood pulp sheet incorporated with three polar functional groups. The synthesis was carried out by graft copolymerization reaction of N,N‐dimethylaminoethylmethacrylate with methacrylic acid onto wood pulp. The preparation conditions at which the grafting process proceeds homogeneously are determined. Characterization and some selected properties of the original and grafted wood pulp were evaluated using FTIR and scanning electron microscope, also, the removal of phenol, benzene, and toluene on laboratory scale was investigated by using gas chromatography. It was found that phenol shows the highest removal percent than that of benzene and toluene. The efficiency of removal of the nonionic contaminants is found to be 97%, which shows a great promise for its applicability in the removal of organic contaminates from wastewater. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3589–3595, 2006 相似文献
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Shafeeque G. Ansari Mushtaq Ahmad Dar Young-Soon Kim Hyung-Kee Seo Gil-Sung Kim Rizwan Wahab Zubaida A. Ansari Jae-Myung Seo Hyung-Shik Shin 《Korean Journal of Chemical Engineering》2008,25(3):593-598
A comparative study for the nucleation of diamond was carried out using surface treatment like (i) surface scratching with
1 μm diamond paste and (ii) surface etching using chlorine plasma at different RF powers (50, 100 and 150 W). Atomic force
microscopic study shows variation in roughness from 31 nm to 110 nm. Scratching results in random scratches, whereas plasma
etches a surface uniformly. Scanning electron microscopic observations show well faceted crystallites with a predominance
of angular shaped grains corresponding to 〈100〉 and 〈110〉 crystallite surfaces for the scratched as well as plasma etched
substrate. Surface etching at 150 W plasma power results in a better growth in comparison with 50 and 100 W plasma powers.
Chlorine-radical is found responsible for the changes in the growth morphology. Raman spectroscopy shows a sharp peak at 1,332
cm−1 and a peak at ∼1,580 cm−1 for both samples. 相似文献
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This paper describes different dynamic tests carried out on three bridges, B14, B15, and B13, over highway E19, which connects Brussels and Antwerpen in Belgium. Different excitation types are considered: a drop weight, a heavy truck on the bridge, and ambient vibrations mainly due to the traffic under the bridge. Finite-element models are constructed to support and verify the dynamic measurements. The modal parameters are extracted from the response time series using the data dependent system approach. A vector autoregressive model is developed and successfully applied to the measured responses in time domain. Good correlation between the finite-element simulations and the experiments is obtained. 相似文献
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The effect of N fertilizers on nodulation, nitrogenase, nitrate reductase activities and growth of two cultivars of soybean, Clark and Crauford was evaluated in a field experiment. KNO3 or NH4Cl were applied 27 days after planting at 0,16, 32, 64 and 128 kg N/ha. Nodulation and growth of both cultivars significantly increased when N was applied at low levels whereas specific N2-ase activity (SNA) slightly and insignificantly increased. Cv Crauford showed a greater positive response than cv. Clark. Higher rates of KNO3 and NH4Cl (128 kg N/ha) significantly depressed nodulation and SNA but slightly decreased the plant dry matter. Cv. Crauford was more tolerant to N fertilizers than cv. Clark. The decline in SNA was ascribed to increased nitrate reductase activity (NRA) and higher accumulation of nitrites in nodule cytosol. NRA and nitrate contents in nodules of cv. Clark were greater than that in cv. Crauford. Results showed that NH4
+ is the preferred N source with occasional increases in nodule number and weight. This study provides an evidence for the nodulation and growth variability of soybean cultivars fertilized with different levels of N. The results also suggest that diminishing NRA could contribute to increased N2 fixation and the interaction between NO3
– assimilation and N2 fixation is strongly dependent on the plant cultivar. 相似文献