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The nano-scaled Sn–3.5Ag solder was prepared successfully by a supernatant process in the present study. The morphology of the nano-particle was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. It was found from the SEM micrographs that the average diameter of the particle was 137 nm with a standard deviation of ±5 nm. From the TEM studies it was revealed that the particles aggregated into larger particles and the shape of the elongated particles were irregular. The composition of the alloy was also measured by an electron probe microanalyzer (EPMA) and energy dispersive spectroscopy (EDS), qualitatively and quantitatively. The eutectic element, Ag with a weight percentage of 3.5%, was found to be homogenous over all of the particles. Furthermore, the microstructure of the Sn–3.5Ag alloy was identified by X-ray diffraction. It was found that the trace element, Ag was dissolved in the matrix, a tetragonal system, without an intermetallic phase. 相似文献
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Studies were conducted on harvesting of Bacillus thuringiensis (Bt)-based biopesticides from fermented broths of starch industry wastewater (SIW), wastewater sludge (raw and hydrolyzed-NH and TH, respectively) and semi-synthetic soyameal to enhance entomotoxicity (Tx) by centrifugation. Pertinent factors influencing Tx, solids concentration, pH, temperature and centrifugal force were investigated. The centrifugate solids concentration beyond 100 g/l did not enhance Tx, instead caused pellet formation. Centrifugation efficiency (Tx recovery) was higher at pH 4, and temperature 20 degrees C for starch wastewater (98%), wastewater sludge (98% and 97.8% for non-hydrolyzed and hydrolyzed, respectively) and soya broth (83%). For maximum Tx recovery (SIW-95%; NH-90%; TH-98% and soya-78%), the centrifugal force and time required was 48,000 g and 30 min, respectively. Losses in recovery efficiency were lower for SIW and wastewater sludge in comparison to soya on adopting commercially recommended centrifugal force of 9000 g. The settling velocity computations for different fermented broths enabled calculation of Sigma factor for continuous commercial centrifuge of a given capacity and hence simulation of power requirements. It was established that power requirements for a given Tx recovery efficiency were highest for conventional medium (soya) in comparison to other waste-based fermented broths. 相似文献
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Extracellular biological organic matters in sewage sludge during mesophilic digestion at reduced hydraulic retention time 总被引:2,自引:0,他引:2
To operate an anaerobic digester at low hydraulic retention time (HRT) is welcome in practice. This study characterized the extracellular biological organic matter (EBOM) and supernatant organics for a sewage sludge digested in a lab-scale mesophilic digester (5 l) running at an HRT of 20, 15 or 10 d. The hydrophilic and hydrophobic acid fractions were the principal components in the sludge EBOM. The hydrolysis rates for hydrophobic acid fraction related EBOM at 10 d HRT and that of hydrophilic fraction related proteins in supernatant at 20 d HRT limited the anaerobic processes. Improved hydrolysis of soluble hydrophilic fraction assisted improving digester performance at 20 d HRT. To shorten digestion HRT, efficiency of hydrophobic acid fraction hydrolysis has to be practiced. 相似文献
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M. Adjdir T. Ali-Dahmane F. Friedrich T. Scherer P.G. Weidler 《Applied Clay Science》2009,46(2):185-189
The alkaline fusion of volclay (a low-cost sodium exchanged smectite) was used as source to generate the Si and Al components which were effectively transformed into mesoporous Al-MCM-41 depending on hydrothermal condition. The Al-MCM-41 materials were investigated by powder X-ray diffraction (XRD), N2 adsorption–desorption measurements and both scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM). The volclay which converted into a silicon and an aluminium source allowed the formation of well ordered mesoporous Al-MCM-41 materials with high aluminium content (roughly 4 times higher than a Al-MCM-41 produced by a standard method), a high specific surface area (1060 m2/g), a pore volume of 0.8 cm3/g (for pore width < 7.1 nm) with an mono-modal pore distribution with a maximum in the mesoporous pore size of 3.8 nm in pore width. 相似文献
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