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Search Results: 1 - 10 of 212559 matches for " Adya P. Singh "
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Short Communication—A Novel Sample Preparation Method That Enables Ultrathin Sectioning of Urea-Formaldehyde Resin for Imaging by Transmission Electron Microscopy  [PDF]
Adya P. Singh, Arif Nuryawan, Byung- Dae Park
Microscopy Research (MR) , 2013, DOI: 10.4236/mr.2013.11001
Abstract: Urea-formaldehyde (UF) resin is widely used as an adhesive for the manufacture of a range of wood and fiber based products. Although the microstructure of this resin has been examined at high resolution by field-emission scanning electron microscopy and atomic force microscopy, transmission electron microscopy (TEM) has thus far not been used, perhaps because of difficulties in ultrathin sectioning this resin in cured (polymerized) state. In the technical note presented here, a novel sample preparation method is described which enabled us to examine the microstructural morphology of UF resin by transmission electron microscopy in ultrathin sections, revealing the presence of spherical particles within the resin. Our initial attempt to ultrathin section the resin directly was not successful as it was too brittle to trim blocks for sectioning. Then, we developed a sample preparation technique that involved impregnation ofPinus radiatawood tissues with the UF resin, and then embedding of resin impregnated wood tissues with Spurr’s low viscosity embedding medium, which has been widely employed in plant and wood ultrastructure work. The TEM images illustrated and the information on the microstructural morphology of the UF resin presented are based on this novel sample preparation approach.
Advances in Probing Wood-Coating Interface by Microscopy: A Review  [PDF]
Adya P. Singh, Byung-Dae Park, Arif Nuryawan, Menda Kazayawoko
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2013, DOI: 10.4236/jsemat.2013.31A007
Abstract:

Surface coatings provide protection to wood products against weathering and other deteriorating factors, such as moisture uptake and microbial invasion. The effectiveness of coatings depends on many factors, including how well the applied coatings adhere to the wood surface. Coating adhesion to wood involves both chemical and physical interactions between the coating and wood tissues in contact, and the particular focus of this mini-review will be on the advances being made in understanding the physical aspects of the interaction by probing wood-coating interface using novel and high resolution imaging techniques, including confocal laser scanning microscopy (CLSM), SEM-backscattered electron imaging and correlative microscopy employing light, confocal and scanning electron microscopy.

Comparative study of solar cycles 22 to 24 in relation to solar output variability  [PDF]
Sham Singh, Divya Shrivastava, Shri Ram Lahauriya, Adya Prasad Mishra
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.46048
Abstract: The rate of increase in solar activity at the initiation of solar cycle 22 had led the activity during the solar maximum years 1990-1991, be the most severe of any period during the space age. Solar cycle 23 started in May 1996 and ended in December 2008. Total time period of this solar cycle is 12.6 years. The maximum smoothed sunspot number observed during the solar cycle was 120.8 and minimum was 1.7. It is apparent that solar cycle 23 is a long one. Solar cycle 24 (initiated in December 2008) seems to be weak, which will have a slow ramp up, much slower than the late 19th century cycles used for comparison. In the present work, we have considered Sunspot number (Rz) as an index of solar activity, which shows a predominant 11 year cycle. The strength of the solar cycle makes a huge difference to satellite operators. Each solar peak heats and expands the outer atmosphere. The strength of the solar-cycle length, annual average and temperature correlation enables solar cycle length to be used as a climate predictor tool.
Genetic Engineering of Field, Industrial and Pharmaceutical Crops  [PDF]
Hari P. Singh, Bharat P. Singh
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.526416
Abstract: Ability to modify plants at the genomic level by advanced molecular technology has enhanced the scope of improvements in plant traits attempted earlier through conventional breeding methods. Techniques such as genetic transformation have opened new vistas whereby functional genes, not commonly present in a particular species can be added from other species. The traits incorporated into the genetically engineered plants in the beginning were confined to those governed by dominant genes, e.g. insecticide resistance and herbicide tolerance but advancements with time now also permit the transfer of complexly inherited traits such as drought and cold tolerance. Transgenic technology is also useful in understanding gene expression and metabolic pathways which can then be used to harness the full genomic potential of the plant. This review presents a narrative on development of transgenics and their use for the improvement of field, industrial and pharmaceuticals crops. In addition, discussions are made on current status on genetically modified crops, hurdles to genetic engineering, overcoming strategies and future scope.
Two Dimensional Heisenberg Exchange Interaction in the Magnetization Studies of Multiferroic  [PDF]
Shegaw Enyew, P. Singh
World Journal of Condensed Matter Physics (WJCMP) , 2012, DOI: 10.4236/wjcmp.2012.24037
Abstract: Multiferroics are novel classes of materials that exhibit cross-coupling of mutually excluding phenomena, i.e. magnetism and ferroelectricity. In recent years, the coexistence of ferroelectricity and magnetic orderings has become a hot issue and drawn considerable attentions due to the promising applications to these days technology and the fundamental science involved in these classes of materials. The microscopic origins of magnetism and ferroelectricity differ fundamentally, while the real mechanism of ferroelectricity is still under debate. In the present work, we have started from a simple method Heisengerg hamiltonian and an interaction term resulting from electric field coupling with the magnetic spins with anisotropic limit, demonstrated that magnetization can be manipulated by electric field and anisotropic field in agreement with results experimentally observed. In the multiferroic thin film system the magnetic field tends to play a role in stabilizing the spins in preferred orientations and induces a coupling of magnetism and ferroelectricity that opens a route to switch magnetization with electric polarazation and vice-versa.
Coexistence of Superconductivity and Antiferromagnetism in SmAsO1-xFxFe  [PDF]
Abera Mebrahtu, P. Singh
World Journal of Condensed Matter Physics (WJCMP) , 2015, DOI: 10.4236/wjcmp.2015.53016
Abstract: Superconductivity and magnetism have been interesting topics in condensed mater physics and they have been studied experimentally and theoretically for many years. These two cooperative phenomena are antagonistic until the discovery of some rare earth ternary compounds that show the coexistence of superconductivity and magnetism. In some of the recently discovered iron-based layered superconductors, superconductivity and magnetism coexist. In the present work we examine the possibility of coexistence of antiferromagnetism and superconductivity in samarium arsenide oxide superconductor (SmAsO1-xFxFe). Using a model of the Hamiltonian and retarded double time Greens function formalism, we found expressions AFM order Parameter (η) and AFM transition temperature (Tm). We obtained the phase diagrams (Tc vs η) and(Tm vs η) to obtain the region where orders, i.e., superconductivity and AFM (antiferromagnetism), coexisted. The region under the intersection of the two merged graphs shows that superconductivity and AFM coexist in the system (SmAsO1-xFxFe).
Berry Approach to Intrinsic Anomalous Hall Conductivity in Dilute Magnetic Semiconductors (Ga1-xMnxAs)  [PDF]
Sintayehu Mekonnen, P. Singh
World Journal of Condensed Matter Physics (WJCMP) , 2015, DOI: 10.4236/wjcmp.2015.53019
Abstract: We develop a model Hamiltonian to treat intrinsic anomalous Hall conductivity in dilute magnetic semiconductor (DMS) of type (III, Mn, V) and obtain the Berry potential and Berry curvature which are responsible for intrinsic anomalous Hall conductivity in Ga1-x MnxAs DMS. Based on Kubo formalism, we establish the relation between Berry curvature and intrinsic anomalous Hall conductivity. We find that for strong spin-orbit interaction intrinsic anomalous Hall conductivity is quantized which is in agreement with recent experimental observation. In addition, we show that the intrinsic anomalous Hall conductivity (AHC) can be controlled by changing concentration of magnetic impurities as well as exchange field. Since Berry curvature related contribution of anomalous Hall conductivity is believed to be dissipationless, our result is a significant step toward achieving dissipationless electron transport in technologically relevant conditions in emerging of spintronics.
Evaluation of Non-Point Source N and P Loads in a Small Mixed Land Use Land Cover Watershed  [PDF]
Ashok Mishra, Rajendra Singh, Vijay P. Singh
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.24042
Abstract: Non-point source pollution (NPS) of water resources has become a major problem in recent years due to more human interactions and disturbances to natural landscapes. The problem can have more impacts in sub-humid subtropical regions where high intensity monsoon rains have greater effects on hydrologic proc-esses and thus the assessment of those effects is necessitated for strategic water resources and environmental management. Since spatial and temporal changes of NPS pollutants are difficult to assess on a watershed scale, the assessment can be done effectively using a suitable water quantity-quality model coupled with GIS and remote sensing that incorporates spatial variations. The objective of this study was to assess the N and P loads from a small mixed type watershed comprising different land use land covers with the aid of Soil and Water Assessment Tool (SWAT)-a hydrologic-water quality model. The model was calibrated for runoff and sediment transport and then simulation of associated N and P loads as NPS pollution was done and compared with measured values at the outlet of the watershed which is part of the DVC Command, Hazaribagh, India. The calibrated SWAT model was used to estimate the water soluble NO3-N, NH4-N, P, organic N and or-ganic P loads being transported as pollutants by runoff and percolated water. The estimates of these pollut-ants provided information on the extent of NPS pollution of water downstream. The results of the study re-veal that the NPS pollutant load in runoff varies with seasonal rainfall patterns and ranges from 2.57 to 4.52 kg/ha in case of NO3-N which accounts for a maximum load of 7661.40 kg of NO3-N in surface runoff from the watershed under study. The total loss of N from the watershed accounts for as high as 8.84 kg/ha, whereas the P load is 0.02 kg/ha. These losses can be as high as 14984.14 kg of total N and 50.85 kg of total P when estimated as NPS pollutants from the watershed. The study is therefore important to get an estimate of the extent of these pollutants and develop measures for mitigating the losses as nutrient as well as pollu-tion of water resources.
Cardiovascular Haemodynamics and Some Biochemical Profiles of Endotoxemic Buffalo Calves on Infusion of HSS, Flunixin Meglumine & Blood  [PDF]
J. P. Singh, D. V. Singh
Journal of Biomedical Science and Engineering (JBiSE) , 2018, DOI: 10.4236/jbise.2018.116011
Abstract: Six apparently healthy male buffalo calves aged between 6 months to one year with body weight range of 70 - 140 Kg were used in the present investigation. One animal was used for pilot trial for this group. Five calves were randomly taken into this group. The Eschrechia coli endotoxin infused i/v @5 mg/kg BW/hr for 3 hours to all the animals caused symptoms of restlessness, respiratory distress, snoring, diarrhea, profuse salivation along with the significant fall in systolic, diastolic, pulse and mean arterial venous pressure, hypoproteinemia at 1, 2 & 3 hour and hypoglycemia at 3rd hour i.e., end of endotoxin infusion. Respiration was increased significantly during endotoxin infusion at 2nd & 3rd hour and even afterwards till the end of the observation period i.e. 7 hrs. The treatment with hypertonic saline solution, flunixin meglumine and blood raised (p < 0.05) the systolic, diastolic, pulse, mean arterial, central venous pressure, plasma total protein, Albumin, Glucose and Creatinine to levels either close to or even higher than the normal pre-infusion levels while hematocrit and hemoglobin increased significantly at 7th hour and at 5th, 6th & 7th hour respectively i.e., till the end of the observation period. There was no significant effect on Central Venous Pressure (CVP) and body temperature as measured from rectum.
Model for Assessment of Child Mortality under Different Parity: A Bayesian Swatch  [PDF]
Arunabh Tripathi, G. P. Singh, Abhinav Singh
Journal of Biosciences and Medicines (JBM) , 2019, DOI: 10.4236/jbm.2019.75014
Abstract: In this study a model is conceptualized to measure the child mortality under different parity of women such that a better strategy can be formulated to bring down mortality rates. In the estimation of probability of child mortality some socio demographic variables are taken in consideration. The estimates are obtained under Bayesian procedure. Two different models are formulated for it and model fitting is observed by graphical approach along with the chi square test. First model is betabinomial and second is binomial regression model. Second model shows the better fit on the data. The estimate of probability of child mortality at higher parities namely, parity 3, parity 4 and parity 5 were obtained as 0.06, 0.09 and 0.13 respectively on the basis of the second model.
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