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Search Results: 1 - 10 of 389090 matches for " R. P. Singh "
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Microwave Scattering for Soil Texture at X-Band and Its Retrieval Using Genetic Algorithm  [PDF]
Rajesh Tiwari, R. K. Singh, D. S. Chauhan, O. P. Singh, R. Prakash, D. Singh
Advances in Remote Sensing (ARS) , 2014, DOI: 10.4236/ars.2014.33010
Abstract: In the present paper, we have studied the effect of soil textures, i.e., sand, silt and clay on microwave scattering at X-band (10 GHz) at various incidence angles and like polarizations (i.e., Horizontal-Horizontal; HH-, Vertical-Vertical; VV-). We have proposed a retrieval technique based on Genetic Algorithm (GA) to retrieve soil texture. For this purpose, ten types of soil mixtures having different percentage of sand, silt and clay have been analyzed. The observations were carried out by ingeniously assembled X-band scatterometer. A good agreement has been noticed between estimated and observed soil texture. Study infers that soil texture is quite sensitive to radar scattering and it is possible to retrieve soil texture with radar/scatterometer data with good accuracy and this type of retrieved results can be helpful to predict soil strength as well as soil erosion of the particular area.
Automatization of Forest Fire Detection Using Geospatial Technique  [PDF]
Shaily R. Gandhi, Tarun P. Singh
Open Journal of Forestry (OJF) , 2014, DOI: 10.4236/ojf.2014.44036
Healthy forest is the vital resource to regulate climate at a regional and global level. Forest fire has been regarded as one of the major reasons for the loss of forest and degradation of the environment. Global warming is increasing its intensity at an alarming rate. Real-time fire detection is a necessity to avoid large scale losses. Remote sensing is a quick and cheap technique for detecting and monitoring forest fires on a large scale. Advance Very Radiometer Resolution (AVHRR) has been used already for a long period for fire detection. The use of Moderate Resolution Imaging Radio Spectrometer (MODIS) for fire detection has recently preceded AVHRR and a large number of fire products are being developed. MODIS based forest fire detection and monitoring system can solve the problem of real-time forest fire monitoring. The system facilitates data acquisition, processing, reporting and feedback on the fire location information in an automated manner. It provides location information at 1 × 1 kilometer resolution on the active fires which are present during the satellite overpass twice a day. The users are provided with the information on SMS alert with fire location details, email notification, and online visualization of fire locations on website automatically. The whole processes are automated and provide better accuracy for fire detection.
Bulk Viscous Anisotropic Cosmological Models with Dynamical Cosmological Parameters G and ∧  [PDF]
S. Kotambkar, G. P. Singh, R. Kelkar
Natural Science (NS) , 2015, DOI: 10.4236/ns.2015.74021
Abstract: This paper deals with the Bianchi type I anisotropic models of the universe, filled with a bulk viscous cosmic fluid, in the presence of variable gravitational and cosmological constants. Some exact solutions of Einstein’s gravitational field equations with bulk viscosity, gravitational and cosmological constants have been obtained. Several well known forms of cosmological terms have been considered to discuss the effect of cosmological variables. The new cosmological models presented in this paper approaches to isotropic model with evolution of universe. The physical and dynamical properties of the models have also been discussed.
Valence Bond Glass Phase in the Diluted Kagome Antiferromagnets
R. R. P. Singh
Physics , 2010, DOI: 10.1103/PhysRevLett.104.177203
Abstract: We present a theory for site dilution in the Valence Bond Crystal Phase of the Kagome Lattice Heisenberg Model. The presence of an empty site leads to strong singlet bond across the impurity. It also creates a free spin, which delocalizes inside the unit cell. Finite concentration of quenched impurities leads to a Valence Bond Glass phase. This phase has short-range Valence Bond order, no spin-gap, large spin susceptibilities, linear specific heat due to two-level systems, as well as singlet and triplet excitations that decompose into kink-antikink pairs delocalized over a few lattice constants. It provides a framework for a comprehensive understanding of thermodynamic, neutron, and Raman measurements in the Herbertsmithite material ZnCu3(OH)6Cl2, including recently reported H/T and omega/T scaling.
Continuing professional development for principals: A South African perspective
R Mestry, P Singh
South African Journal of Education , 2007,
Treatment of pompholyx with dapsone
Singh R,Snehi P
Indian Journal of Dermatology, Venereology and Leprology , 1993,
Abstract: Seventy six patients having pompholyx of 1 month to 2 years duration were treated with dapsone (DDS) initially with 4 mg/kg/day in two divided doses till clearance of lesions occurred and then with 2 mg/kg/day for a period of 2 weeks. Complete clearance of lesions occurred in all cases in 4 to 18 days (average 7.62 days). Relapse was noted in 4 cases, only one of which required long term maintenance dose for 3 months. A control group of 16 patients were treated with placebo and saline compresses for 3 weeks. Only 3 cases of this group showed clearance of the lesions.
Neutron spectra of Herbertsmithite Materials: Observation of a Valence Bond Liquid phase?
Rajiv R. P. Singh
Physics , 2010,
Abstract: We argue that neutron spectra in a short-range ordered Valence Bond state is dominated by two-spinon states localized in small spatial regions such as a pinwheel. These excitations lead to angle averaged dynamic structure factor that is spread over a wide frequency range up to about $2.5 J$, whereas its wavevector dependence at all frequencies remains very close to that of isolated dimers. These results are in excellent agreement with recent Neutron scattering data in the Herbertsmithite materials ZnCu$_3$(OH)$_6$Cl$_2$.
Spinons, Solitons and Magnons in One-dimensional Heisenberg-Ising Antiferromagnets
Rajiv R. P. Singh
Physics , 1995, DOI: 10.1103/PhysRevB.53.11582
Abstract: We calculate the excitation spectra for the one-$d$ Heisenberg-Ising antiferromagnets by expansions around the Ising limit. For $S=1/2$, the calculated expansion coefficients for the spinon-spectra agree term by term with the solution of Johnson and McCoy. For $S=1$, the solitons become gapless before the Heisenberg limit is reached, signalling a transition to the Haldane phase. By applying a staggered field we calculate the one-magnon spectra for the $S=1$ Heisenberg chain. For $S=3/2$ the quantum renormalization of the spin-wave spectra is calculated to be approximately $1.16$.
Exchange Constants and Neutron Spectra of Iron Pnictide Materials
Rajiv R. P. Singh
Physics , 2009,
Abstract: We show that the neutron scattering spectra observed in CaFe$_2$As$_2$ by Zhao et al (arXiv:0903.2686v1) and the highly unusual spatially anisotropic exchange constants in the iron pnictides derived by Han et al (Phys. Rev. Lett. 102, 107003 (2009)), using electronic structure calculations, can be explained by assuming a role for orbital order in these materials. We write down a simple model Hamiltonian with tertagonal symmetry, whose spin-wave spectra describes the observed dispersion relations. We further argue that these materials have orbital selective Mott transition, which is driven by superexchange between neighboring iron atoms. We suggest that reduced spin and quasi-one dimensionality and not frustration are responsible for the reduced moments in these materials.
A Novel High-Performance Lekage-Tolerant, Wide Fan-In Domino Logic Circuit in Deep-Submicron Technology  [PDF]
Ajay Dadoria, Kavita Khare, T. K. Gupta, R. P. Singh
Circuits and Systems (CS) , 2015, DOI: 10.4236/cs.2015.64011
Abstract: As technology shrinks in modern era the demand on high speed, low power consumption and small chip area in microprocessors is come into existence. In this paper we have presented a new class of domino circuit design for low power consumption, faster circuit speed and high performance. Due to wide fan-in domino logic, its logic gate suffer from noise sensitivity, if we improve sensitivity, sub-threshold and gate oxide leakage current dominate in evaluation network, which increases the power consumption and reduces the performance of the circuit. The proposed circuit improves the dynamic power consumption and reduces the delay which improves the speed of the circuit. Simulation is performed in BISM4 Cadence environment at 65 nm process technology, with supply voltage 1 V at 100 MHz frequency and bottleneck operating temperature of 27°;C with CL = 1 fF. From the result average power improvement by proposed circuit 1 & 2 for 8 input OR gate is 10.1%, 15.28% SFLD, 48.56%, 51.49% CKD, 55.17%, 57.71% HSD and improvement of delay is 1.10%, 12.76% SFLD, 19.13%, 28.63% CKD, 4.32%, 15.59% HSD, 19.138%, 44.25% DFD respectively.
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