Synthesis and characterization of supported polysugar-stabilized palladium nanoparticle catalysts for enhanced hydrodechlorination of trichloroethylene

Palladium (Pd) nanoparticle catalysts were successfully synthesized within an aqueous phase using sodium carboxymethyl cellulose (CMC) as a capping ligand which offers a green alternative to conventional nanoparticle synthesis techniques. The CMC-stabilized Pd nanoparticles were subsequently dispersed within support materials using the incipient wetness impregnation technique for utilization in heterogeneous catalyst systems. The unsupported and supported (both calcined and uncalcined) Pd nanoparticle catalysts were characterized using transmission electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction, and Brunauer-Emmett-Teller surface area measurement and their catalytic activity toward the hydrodechlorination of trichloroethylene (TCE) in aqueous media was examined using homogeneous and heterogeneous catalyst systems, respectively. The unsupported Pd nanoparticles showed considerable activity toward the degradation of TCE, as demonstrated by the reaction kinetics. Although the supported Pd nanoparticle catalysts had a lower catalytic activity than the unsupported particles that were homogeneously dispersed in the aqueous solutions, the supported catalysts retained sufficient activity toward the degradation of TCE. In addition, the use of the hydrophilic Al(2)O(3) support material induced a mass transfer resistance to TCE that affected the initial hydrodechlorination rate. This paper demonstrates that supported Pd catalysts can be applied to the heterogeneous catalytic hydrodechlorination of TCE.     

Simultaneous production of hydrogen and carbon nanostructures by decomposition of propane and cyclohexane over alumina supported binary catalysts

Nano-scale, binary, 4.5 wt.% Fe–0.5 wt.% M (M = Pd, Mo or Ni) catalysts supported on alumina have been shown to be very effective for the decomposition of lower alkanes to produce hydrogen and carbon nanofibers or nanotubes. After pre-reduction at 700 °C, all three binary catalysts exhibited significantly lower propane decomposition temperatures and longer time-on-stream performances than either the non-metallic alumina support or 5 wt.% Fe/Al₂O₃. Catalytic decomposition of propane using all three catalysts yielded only hydrogen, methane, unreacted propane, and carbon nanotubes. Above 475 °C, hydrogen and methane were the only gaseous products. Catalytic decomposition of cyclohexane using the (4.5 wt.% Fe–0.5 wt.% Pd)/Al₂O₃ catalyst produced primarily hydrogen, benzene, and unreacted cyclohexane below 450 °C, but only hydrogen, methane, and carbon nanotubes above 500 °C. The carbon nanotubes exhibited two distinct forms depending on the reaction temperature. Above 600 °C, they were predominantly in form of multi-walled nanotubes with parallel walls in the form of concentric graphene sheets. At or below 500 °C, carbon nanofibers with capped and truncated stacked-cone structure were produced. At 625 °C, decomposition of cyclohexane produced a mixture of the two types of carbon nanostructures.     

Renewable energy in India: Current status and future potentials

Renewable energy sources and technologies have potential to provide solutions to the long-standing energy problems being faced by the developing countries. The renewable energy sources like wind energy, solar energy, geothermal energy, ocean energy, biomass energy and fuel cell technology can be used to overcome energy shortage in India. To meet the energy requirement for such a fast growing economy, India will require an assured supply of 3–4 times more energy than the total energy consumed today. The renewable energy is one of the options to meet this requirement. Today, renewable account for about 33% of India's primary energy consumptions. India is increasingly adopting responsible renewable energy techniques and taking positive steps towards carbon emissions, cleaning the air and ensuring a more sustainable future. In India, from the last two and half decades there has been a vigorous pursuit of activities relating to research, development, demonstration, production and application of a variety of renewable energy technologies for use in different sectors. In this paper, efforts have been made to summarize the availability, current status, major achievements and future potentials of renewable energy options in India. This paper also assesses specific policy interventions for overcoming the barriers and enhancing deployment of renewables for the future.     

Semi-continuous hydrogen production from catalytic methane decomposition using a fluidized-bed reactor

Non-oxidative, catalytic decomposition of hydrocarbons is an alternative, one-step process to produce pure hydrogen with no production of carbon oxides or higher hydrocarbons. Carbon produced from the decomposition reaction, in the form of potentially valuable carbon nanotubes, remains anchored to the active catalyst sites in a fixed bed. To facilitate periodical removal of this carbon from the reactor and to make hydrogen production continuous, a fluidized-bed reactor was envisioned. The hypothesis that the tumbling and inter-particle collisions of bed material would efficiently separate nanotubes anchored to the active catalyst sites of the bed particles was tested and shown to be invalid. However, a switching mode reaction system for the semi-continuous production of hydrogen and carbon nanotubes by periodic removal and replenishment of the catalytic bed material has been successfully demonstrated.     

CHECK-IT:中国—荷兰信息技术应用能力开发实习项目(英文)

This paper presents CHECK-IT(China-Holland Education Competence Knowledge on Information Technology) to effectively develop crucial software engineering skills in students of the software Engineering curriculum at the Xiamen University.The objective of the program is to cultivate the talents with international vision and real-project experience.CHECK-IT carefully designes project bridges the gap between theoretical knowledge and lively experience.This scheme has been in use for some time and proved to be not only efficient and effective but also quite rewarding for both students and instructors of both side.It's discussed important characteristics of CHECK-IT as well as processes,central issues,relevant lessons learned and future development in the paper.     

Rapid and miniaturized method for detection of hygiene indicators,Escherichia coli and coliforms,in dairy products

Current investigation was aimed to develop colorimetric tests for rapid detection of Escherichia coli/coliforms. These test (s) for E. coli and coliforms were developed using the modified E. coli selective medium (M-ECSM) and coliform selective medium, respectively. The selective media contain a combination of group specific marker enzymes and selective agents. The marker enzymes were screened using chromogenic substrates wherein β-D-glucuronidase and glutamate decarboxylase were found specific for E. coli while β-D-galactosidase for coliforms. The selectivity of the media was achieved using different concentrations of ampicillin and gentamicin. The optimized test procedures enabled sensitive detection of 0.35 ± 0.10 log cfu/ml of E. coli and 0.57 ± 0.15 log cfu/ml of coliforms at 37°C within 14.30 ± 0.45 and 12.15 ± 0.30 hr, respectively. M-ECSM selectively inhibited major Enterobacteriaceae contaminants (Salmonella, Shigella, and Yersinia) up to 6 log cfu/ml. Moreover, better selectivity of M-ECSM was reported against tested commercial chromogenic media. Field evaluation of developed test (s) reported prevalence of E. coli/coliforms as 57.29/88.54% in 96 raw milk and 16.28/51.16% in 43 pasteurized milk samples. Further, test components were vacuum dried in the form of miniaturized point-of-need test for field application in dairy farms and industries with minimal infrastructural requirements.     

Antifouling behaviour of PVDF/TiO2 composite membrane: a quantitative and qualitative assessment

The composite membranes of PVDF/TiO₂ were prepared by a phase-inversion technique. Different amounts of TiO₂ with respect to the weight of the polymer were incorporated in the casting solution to study qualitatively and quantitatively the antifouling property of the membrane. The membrane morphology was studied using a high-resolution scanning electron microscopy and atomic force microscopy, whereas the crystalline nature was studied using X-ray diffraction method. The interfacial interactions between foulants and TiO₂ immobilized membranes were also evaluated using the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) approach. The XDLVO theory revealed an increase in repulsive interactive energy barrier with an increase in TiO₂ loading, thus causing to improve the antifouling property of the membrane. Intercalation of TiO₂ nanoparticles efficiently improved the porosity and wettability of the polymeric membranes, which could be confirmed by the contact angle analyzer analysis. The modified PVDF membranes exhibited excellent antimicrobial properties against Gram-negative Escherichia coli as confirmed from the halo zone and activity test. The permeation experimental results also showed high protein rejection of bovine serum albumin and humic acid (foulant) for membranes with optimum TiO₂ loading of 0.01 g/g of PVDF polymer. However, at a concentration of 0.02 g TiO₂/g of PVDF a negative effect on the membrane property was observed due to the former non-uniform distribution.

     

Hydrocarbons from males,females, and larvae of pecan weevil:Curculio caryae (Horn)

As part of a program to identify as many as possible of the components of the pecan weevil,Curculio caryae (Horn), the hydrocarbons from males, females, and larvae were isolated by solvent extraction and column chromatography and subjected to gas liquid chromatographymass spectrometry analysis. n-Alkanes from C₁₄−C₃₂ in the larvae and unsaturated and branched chain hydrocarbons from C₂₀−C₃₂ in males and females were found. There are no significant differences between the hydrocarbons of the male and female pecan weevils.