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Search Results: 1 - 10 of 321829 matches for " P. K. Singh "
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Enrichment of Cobalt Values by Dry Magnetic Separation from Low-Grade Manganese Ores of Bonai-Keonjhar Belt, Orissa  [PDF]
P. P. Mishra, B. K. Mohapatra, P. P. Singh
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.84028
Abstract: Resource potential of cobalt in India is practically negligible. Cobalt in marine manganese nodule though known since long, its report from terrestrial manganese ore is least observed. This paper reports the occurrence of cobalt in low-grade manganese ores of Bonai-Keonjhar belt, Orissa, eastern India and describes methods for its possible enrichment. Cobalt is associated with manganese minerals like lithiophorite (~CoO: 1.2%) and cryptomelane (~CoO: 0.2%). A feed of low-grade siliceous manganese ore containing 26% Mn and 32% SiO2 and 0.08% Co was subjected to physical beneficiation. By processing the low-grade siliceous ore on a dry belt magnetic separator, a product with 47% Mn at 60% recovery could be obtained. It was observed that along with manganese the cobalt value gets enriched (~Co: 0.38%) more than four times in comparison to the feed. Some other traces like Ni, Cu, Zn, Ga, Li etc. also get enriched in the magnetic product. Thus, through simple dry magnetic separation a low-valued material cannot only be converted to usable product but two valuable metals can also be recovered from it.
Design of 2D-Bootlace Lens with Five Focal Feed for Multiple Beam Forming  [PDF]
Ravi Pratap Singh Kushwah, P. K. Singhal
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2011, DOI: 10.4236/jemaa.2011.32007
Abstract: Utility of microwave bootlace lens is well established. For broadband and wide scanning network, it is required to op-timize and use features of this lens for better communication and scanning device. This report presents the design of a compact 2D bootlace lens with five focal feed for multiple beam forming. This design will help in reducing phase error and will provide power efficiency and better resolution during target tracking. This design will provide better aperture efficiency and scanning angle.
Comparative Analysis of Parabolic Bootlace Lens and Conventional Lens Approach  [PDF]
Ravi Pratap Singh Kushwah, P. K. Singhal
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2011, DOI: 10.4236/jemaa.2011.32011
Abstract: In this paper, parabolic refocusing lens is designed for the same requirements as Rotman lens. Comparison of results obtained with the parabolic refocusing lens with those obtained for the Rotman lens is also given.
Efficiency and Effectiveness of State Transport Undertakings in India: A DEA Approach  [PDF]
Sanjay K. Singh, Amit P. Jha
Theoretical Economics Letters (TEL) , 2017, DOI: 10.4236/tel.2017.76111
Abstract: The Indian bus transport industry is dominated by the publicly owned State Transport Undertakings (STUs). Most of the STUs have, over the years, accumulated financial losses. However, since STUs offer their services with a social aim, financial losses faced by them may not be bad per se. For publicly owned organizations, efficiency and effectiveness are more important than mere profitability. This paper attempts to measure the efficiency and effectiveness of fifteen major STUs in India for the period 2003-04 to 2013-14 using Data Envelopment Analysis (DEA). The paper also examines STUs’ scale elasticity and its relationship with firm size. It is found that the STUs operating in the state of West Bengal are not only the least efficient but also the least effective whereas Andhra Pradesh state road transport corporation, which is the largest bus transport operator in the world, is the most efficient and effective operator. In general, there is a strong positive correlation between STUs’ efficiency and their effectiveness. On the other hand, there is a negative relationship between size of the STUs and returns to scale; large size firms are showing decreasing returns to scale whereas small size ones are operating on increasing returns to scale. Therefore, a size correction through mergers, demergers or altering scale of operation, as the case may be, will be economically prudent.
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.
Enhanced Spectrum Utilization for Existing Cellular Technologies Based on Genetic Algorithm in Preview of Cognitive Radio  [PDF]
K. SRIDHARA, Aritra NAYAK, Vikas SINGH, P. K. DALELA
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.29107
Abstract: This paper attempts to find out the distributed server-based dynamic spectrum allocation (DSA) within liberalized spectrum sharing regulation concept as an alternative to existing regulation based on fixed frequency spectrum allocation schemes towards development of cognitive radio for coverage-based analogy. The present study investigates a scenario where a block of spectrum is shared among four different kinds of exemplary air interface standards i.e., GSM, CDMA, UMTS and WiMAX. It is assumed to offer traffic in an equally likely manner, which occupy four different sizes of channel bandwidths for different air interfaces from a common pooled spectrum. Four different approaches for spectrum pooling at the instance of spectrum crunch in the designated block are considered, viz. channel occupancy through random search, existing regulation based on fixed spectrum allocation (FSA), FSA random and channel occupancy through Genetic Algorithm (GA) based optimized mechanism to achieve desired grade of service (GoS). The comparisons of all the approaches are presented in this paper for different air interfaces which shows up to 55% improvement in GoS for all types of air interfaces with GA-based approach in comparison to existing regulations.
Metallurgical Use of Heat Altered Coal: A Case Study  [PDF]
Debjani Nag, A.K. Singh, P.K. Banerjee
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.87047
Abstract: The effects of igneous intrusion on coal are observed in various parts of the world. It is found that igneous intrusions have altered the quality and characteristics, especially the coke ability of the coals. It has been estimated that a large quantity of heat affected (jhama) coal is reserved in the Jharia collieries of India. Nowadays, apart from difficulties of mining, its utilization is the biggest issue. This paper presents a brief overview of heat altered coal and also highlights some studies, undertaken in Tata Steel to make best possible metallurgical use of jhama especially in steel industry.
Apatite Microstructure and Composition in Manganese Formation of Eastern Ghats, Orissa, India  [PDF]
Subhasmita Jena, B.K. Mohapatra, P. P. Singh
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.105030
Abstract: Apatite grains in a stratabound manganese ore body from Eastern Ghats in Leliguma, Koraput district south Orissa, India were studied under optical and electron microscope. Apatite shows bimodal occurrence: one associated with granite/pegmatitic phase and other with manganese phase, and exhibits different microstructure and composition. Apatite in pegmatitic association (occurring as inclusion in quartz and feldspar) is small in size and occurs as subhedral grains having irregular boundaries and poor in manganese content (MnO: 0.16%). Apatite associated with manganese mineral phases (cryptomelane / romanechite) is mostly euhedral, relatively larger in size, contains higher manganese value, and exhibits some peculiar features like twinning, zoning, overgrowth, and occasionally contains inclusion of quartz and feldspar grains. Apatite grains occurring as inclusions within quartz and feldspar are of hydrothermal origin and formed along with pegmatitic minerals. Such apatite is almost devoid of manganese but relatively enriched in Sr, F and LREE content. The apatite in manganese mineral association formed during supergene process. The apatite of latter generation appears as idiomorphic crystals; contains up to 6.85% of MnO in solid solution and shows relatively higher HREE values. The higher HREE values may be due to its derivation from stratiform Mn-ore bodies and associated granitised rock during remobilization, solution and precipitation of Mn –rich fluid along structurally weak planes resulting in development of a stratabound ore body.
Viscous Dissipation and Variable Viscosity Effects on MHD Boundary Layer Flow in Porous Medium Past a Moving Vertical Plate with Suction
P. K. Singh
International Journal of Engineering Science and Technology , 2012,
Abstract: This paper deals with the problem of a steady two dimensional boundary layer flow of an incompressible, viscous and electrically conducting fluid, with heat and mass transfer, past a moving vertical porous plate in the presence of uniform magnetic field applied normal to the plate, taking into account the effects of variable viscosity and viscous dissipation. The equations of motion, heat and mass transfer are transformed into a system of coupled ordinary differential equations in the non-dimensional form which are solved numerically. The effects of various parameters such as Prandtl number, Eckert number and Schmidt number on the velocity, temperature and concentration fields are discussed with the help of graphs.
Data Forwarding in Adhoc Wireless Sensor Network Using Shortest Path Algorithm
P.K. Singh
Journal of Global Research in Computer Science , 2011,
Abstract: Wireless sensor networks find potential in military, environments, health and commercial applications. The process of forwarding data from a remote sensor node to other nodes in a network holds importance for such applications. Various constraints such as limited computation, storage and power makes the process of data routing interesting and has opened new arenas for researchers. The fundamental problem in sensor networks states the relevance and routing of data through a genuine path as path length decides some basic performance parameters for sensor networks. This paper strongly focuses on a shortest path algorithm for adhoc networks. The simulations are performed on NS2 and the results obtained discuss the role of data forwarding through a shortest path.
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