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Summary In Kumaun Himalaya, India, 60 percent of the rural population is dependent on natural springs for water supply. The authors claim that substantial reductions in spring water discharges are due to losses in the indigenous oak forest coverage and its partial replacement by pine. Other factors, such as overall forest cover depletion and construction activities, combine to produce severe reductions in spring discharge rates.Drs Anil Singh and Ravindra Pande are members of academic staff at Kumaun University working in the Laboratory for Hydrological and Geomorphological Investigations in the Department of Geography. 相似文献
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Surface distortions in the form of wrinkles are often observed in sheet metals during stamping and other forming operations. Because of the trend in recent years towards thinner, higher-strength sheet metals, wrinkling is increasingly becoming a more common and troublesome mode of failure in sheet metal forming. The prediction and prevention of wrinkling during a sheet forming process are important issues for the design of part geometry and processing parameters. This paper treats the phenomenon of flange wrinkling as a bifurcated solution of the equations governing the deep drawing problem when the flat position of the flange becomes unstable. Hill’s bifurcation criterion is used to predict the onset of flange wrinkling in circular and square cup drawing. In particular, the maximum cup height that can be drawn without the onset of flange wrinkling is predicted for the given set of process parameters. A parametric study of the maximum cup height is also carried out with respect to various geometric, material and process parameters. Finite element formulation, based on the updated Lagrangian approach, is employed for the analysis. The incremental logarithmic strain measure, which allows the use of a large incremental deformation, is used. The stresses are updated in a material frame. The material is assumed to be elastic–plastic, strain hardening, yielding according to an anisotropic yield criterion of Barlat et al. (2005) [23] (named as Yld2004-18p). Isotropic power law hardening is assumed. Inertia forces are neglected due to small accelerations. Modified Newton–Raphson iterative technique is used to solve the nonlinear incremental equations. 相似文献
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Shweta Paroha Arvind K. Singh Chandel Ravindra Dhar Dubey 《Environmental Chemistry Letters》2018,16(1):71-77
Coenzyme Q10 is an antioxidant present in the human body. Coenzyme Q10 has an essential role in various biochemical reactions. The deficiency of coenzyme Q10 in the body leads to disorders including neurological degeneration, ageing and cancer. Clinical trials have tested coenzyme Q10 as a drug or a dietary supplement. However, the major pharmaceutical issue of coenzyme Q10 delivery is its high molecular weight and poor water solubility. This limitation leads to its poor oral bioavailability. Several methods have been designed to overcome the poor water solubility of coenzyme Q10, such as size reduction and ionization. This article presents nanotechnology-based drug delivery systems for coenzyme Q10 with special emphasis on pharmacokinetic perspectives and clinical relevance. Systems include nanoparticles, solid dispersions, liposomes, nanoemulsions, self-emulsifying drug delivery systems, nanostructured lipid carriers, cyclodextrins and nanocapsules. 相似文献
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Goudar Naganagouda Vanjeri Vinayak N. Hiremani Vishram D. Gasti Tilak Khanapure Sheela Masti Saraswati P. Chougale Ravindra B. 《Journal of Polymers and the Environment》2022,30(6):2419-2434
Journal of Polymers and the Environment - The novel polyelectrolyte complexes (PEC) were prepared by mixing different Wt% of Tragacanth gum (TG) to Chitosan (CS) and systematic evaluation of... 相似文献
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Hiremani Vishram D. Goudar Naganagouda Gasti Tilak Khanapure Sheela Vanjeri Vinayak N. Sataraddi Sarala D’souza Oshin Jacintha Vootla Shyam Kumar Masti Saraswati P. Malabadi Ravindra B. Chougale Ravindra B. 《Journal of Polymers and the Environment》2022,30(4):1314-1329
Journal of Polymers and the Environment - This study explains the development of eco-friendly polyvinyl alcohol (PVA)/oxidized maize starch (OMS)/Betel leaves extract (BLE) blend films by employing... 相似文献
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Chemical and biological extraction of metals present in E waste: A hybrid technology 总被引:2,自引:0,他引:2
Management of metal pollution associated with E-waste is widespread across the globe. Currently used techniques for the extraction of metals from E-waste by using either chemical or biological leaching have their own limitations. Chemical leaching is much rapid and efficient but has its own environmental consequences, even the future prospects of associated nanoremediation are also uncertain. Biological leaching on the other hand is comparatively a cost effective technique but at the same moment it is time consuming and the complete recovery of the metal, alone by biological leaching is not possible in most of the cases. The current review addresses the individual issues related to chemical and biological extraction techniques and proposes a hybrid-methodology which incorporates both, along with safer chemicals and compatible microbes for better and efficient extraction of metals from the E-waste. 相似文献
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Gasti Tilak Hiremani Vishram D. Kesti Sheetal Suresh Vanjeri Vinayak N. Goudar Naganagouda Masti Saraswati P. Thimmappa Shivasharana Chandrabanda Chougale Ravindra B. 《Journal of Polymers and the Environment》2021,29(10):3347-3363
Journal of Polymers and the Environment - In this study, we prepared Poly (vinyl alcohol) (PVA)/Guar gum (GG) based nanocomposite films with a different weight ratio of silver nanoparticles (AgNPs)... 相似文献
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Appraisal of salinity and fluoride in a semi-arid region of India using statistical and multivariate techniques 总被引:1,自引:0,他引:1
Suman Mor Surender Singh Poonam Yadav Versha Rani Pushpa Rani Monika Sheoran Gurmeet Singh Khaiwal Ravindra 《Environmental geochemistry and health》2009,31(6):643-655
Various physico-chemical parameters, including fluoride (F−), were analyzed to understand the hydro-geochemistry of an aquifer in a semi-arid region of India. Furthermore, the quality
of the shallow and deep aquifer (using tube well and hand pumps) was also investigated for their best ecological use including
drinking, domestic, agricultural and other activities. Different multivariate techniques were applied to understand the groundwater
chemistry of the aquifer. Findings of the correlation matrix were strengthened by the factor analysis, and this shows that
salinity is mainly caused by magnesium salts as compared to calcium salts in the aquifer. The problem of salinization seems
mainly compounded by the contamination of the shallow aquifers by the recharging water. High factor loading of total alkalinity
and bicarbonates indicates that total alkalinity was mainly due to carbonates and bicarbonates of sodium. The concentration
of F− was found more in the deep aquifer than the shallow aquifer. Further, only a few groundwater samples lie below the permissible
limit of F−, and this indicates a risk of dental caries in the populace of the study area. The present study indicates that regular monitoring
of groundwater is an important step to avoid human health risks and to assess its quality for various ecological purposes. 相似文献
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S. Ravindra K. Varaprasad N. Narayana Reddy K. Vimala K. Mohana Raju 《Journal of Polymers and the Environment》2011,19(2):413-418
Ciprofloxacin (CF) loaded biodegradable microspheres of Poly(lactide-co-caprolactone)-PF127 (a poloxamer block copolymer of Ethylene Oxide/Propylene Oxide) were prepared by using solvent evaporation
technique. The microspheres were characterized by differential scanning calorimetry (DSC) and X-ray diffractometry (X-RD)
technique to confirm the polymorphism of ciproflaxacin (CF) drug. The X-RD and DSC techniques indicated molecular level dispersion
of CF in the microspheres. Scanning electron micrographic images (SEM) of the microspheres indicated smooth surfaces of the
spherical microspheres. Cumulative release characteristics of the matrices for CF, the antibiotic drug, were investigated
in pH 7.4 media. It was possible to release CF in controlled manner up to 72 h. The developed ciprofloxacin loaded Poly(lactide-co-caprolactone)-PF127
microspheres were evaluated for preliminary antibacterial applications. 相似文献