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71.
72.
The variation of groove wear profile, built up edge adhering to the machined surface and surface roughness have been studied. The correlation between the surface roughness (Ra and Rt), groove wear and built up edge is discussed. 相似文献
73.
For machining of composites, abrasive water jet machining is widely employed. For assembly of the machine tool structure, production of slots is essential. In this paper, abrasive water jet machining of composite laminates was experimentally investigated for various cutting parameters in terms of average surface roughness (Ra) and kerf taper (Kt). By generating a response surface model, the experimental values obtained for quality characteristics (Ra and Kt) were empirically related to cutting parameters. The effects of cutting parameters on quality characteristics were analyzed by utilizing empirical models and also optimized within the tested range based on desirability approach. The optimum parameter levels were also validated by confirmation test. From this investigation, it is evident that for obtaining a minimum kerf taper, traverse speed, water pressure, and abrasive mass flow rate are significant parameters and for obtaining less surface roughness traverse speed is the significant parameter. 相似文献
74.
C. Selvam Sivasankaran Harish D. Mohan Lal 《Fullerenes, Nanotubes and Carbon Nanostructures》2017,25(2):86-93
In this study, we report the effective thermal conductivity and rheological behavior of ethylene glycol with single-walled carbon nanohorn inclusions. The thermal conductivity and viscosity was found to increase with respect to nanohorn loading. Maximum thermal conductivity enhancement of ~11% at a nanohorn loading of 1.5 vol% was obtained in this study. The viscosity of nanofluids increase with respect to nanohorn loading and decreases with respect to shear rate which indicates the non-Newtonian shear thinning behavior at higher nanohorn loading. Finally, the effectiveness of nanofluids was calculated for laminar and turbulent regions to predict the heat transfer performance and favorability of these nanofluids. The present nanofluids are favorable upto 0.1 vol% in the laminar region. However, these nanofluids are not favorable for turbulent region and loadings beyond 0.1 vol% due to higher viscosity enhancement. 相似文献
75.
Rajesh S. Kempegowda P.V. Pannir Selvam Øyvind Skreiberg Khanh‐Quang Tran 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(7):897-902
BACKGROUND: This paper reports on process synthesis and economics of combined methanol and CHP (combined heat and power) energy production from crude biooil, waste glycerol produced in biodiesel factories and biomass wastes using integrated reactor design for hydrogen rich syngas. This new process consists of three process steps: (a) pyrolysis of organic waste material to produce biooil, char and pyrogas; (b) steam assisted hydrogasification of the crude glycerol wastes, biooil mixed with pyrogas for hydrogen rich gas; and (c) a low temperature methanol synthesis process. The H2‐rich gas remaining after methanol synthesis is recycled back to the pyrolysis reactor, the catalytic hydro‐gasification process and the heat recovery steam generator (HRSG). RESULTS: The breakeven price of the Hbiomethanol process yields positive net financial NPV and IRR above 600 USD per tonne. The total capital cost for a small‐scale methanol plant of capacity 2 tonne h?1 combined with a cogeneration plant of capacity 2 MWe power is estimated to be 170.5 million USD. CONCLUSION: Recycling gas allows the methanol synthesis reactor to perform at a relatively lower pressure than conventionally while the plant still maintains a high methanol yield. The integrated hydrogasification reactor and energy recovery design process minimizes heat loss and increases the process thermal efficiency. The Hbiomethanol process can convert any condensed carbonaceous material and liquid wastes, to produce methanol and CHP. Copyright © 2012 Society of Chemical Industry 相似文献
76.
In the present investigation, leaf and stem bark of Crataeva magna are evaluated for their antioxidant activity and inhibition of key enzymes relevant to hyperglycemia. Both the parts exhibited significant antioxidant and anti-α-glucosidase activity. The results will lead in favor of the use of this plant as a potential additive/nutraceutical antioxidant compound. 相似文献
77.
78.
Nataraj Loganayaki Perumal Siddhuraju Sellamuthu Manian 《Food science and biotechnology》2010,19(1):121-127
In the present study, chloroform, acetone, and methanol extracts of Solanum torvum and Solanum nigrum leaves and fruit were evaluated for their in vitro antioxidant activity using ferric reducing antioxidant power, 2,2-diphenyl-1-picryl-hydrazyl (DPPH), ABTS·+, iron chelation, and antihemolytic activity. Among the various solvents used, the maximum yield was obtained in chloroform
followed by acetone and methanol. The total phenolics were also significantly higher in the chloroform extracts and the in vitro antioxidant activity was shown to be highly dependant on the total phenolic content (p<0.01). The DPPH· and 2,2′azinobis(3-ethylbenzothiozoline-6-sulfonic acid) diammonium salt (ABTS) cation radical scavenging activities were
well proved with the ferric reducing antioxidant capacity of the extracts. The potential of multiple antioxidant activity
of samples can be further evidenced by inhibition of reactive oxygen mediated erythrocyte cell lysis and metal ion chelating
activity. In conclusion, the results presented here implied leaves and fruits of S. torvum and S. nigrum could be considered as health supplements and nutraceuticals/functional foods. 相似文献
79.
Kandhasamy Sowndhararajan Perumal Siddhuraju Sellamuthu Manian 《Food science and biotechnology》2010,19(2):503-509
Antioxidant potential and total phenolics content of 70% acetone extracts of the raw and processed seeds of Bauhinia vahlii were evaluated. The extract of raw seeds contained higher levels of total phenolics (30.8 g/100 g) and tannins (19.6 g/100
g) compared to dry heated and soaking followed by autoclaving seed extracts. Extracts were screened for antioxidant and free
radical scavenging activities using various chemical and in vitro model systems. In all the models, except DPPH radical scavenging activity, the extract from raw seeds manifested the strongest
antioxidant activity than that from processed seeds. In β-carotene/linoleic acid emulsion system and superoxide scavenging
activity, the raw seed extract registered more activity when compared to the standards (butylated hydroxyanisole and α-tocopherol).
Whereas, the extract from dry heated seed exhibited higher DPPH· scavenging activity (IC50 70.77 μg/mL) than the raw seeds (IC50 74.4 μg/mL). This study has to some extent validated the antioxidant potential of the seeds of B. vahlii. 相似文献
80.
Synthesis, Characterization, and Catalytic Properties of Chromium-Containing Hexagonal Mesoporous Aluminophosphate Molecular Sieves 总被引:2,自引:0,他引:2
Chromium-containing hexagonal mesoporous aluminophosphate molecular sieve materials were synthesized, characterized and evaluated for the oxidation of cyclohexane under mild conditions. The catalysts showed remarkable activity for the chosen reaction with very high substrate conversion and excellent product selectivity. In addition, recycling studies over the spent catalysts as well as studies on quenched solutions under the reaction conditions indicated no or very meager loss in activity; thus, the materials behaved truly as heterogeneous catalysts. This observation was well supported by ICP-AES analysis of the filtrates obtained from the washed catalysts where no leaching of active chromium species was detected. Furthermore, the reaction carried out using these filtrates confirmed the absence of active metal ions as it exhibited only a marginal activity. 相似文献