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Search Results: 1 - 10 of 1880 matches for " Baldev Raj "
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Tuning light matter interaction in magnetic nanofluid based field induced photonic crystal-glass structure by controlling optical path length
Junaid M. Laskar,Baldev Raj,John Philip
Physics , 2015,
Abstract: The ability to control the light matter interaction and simultaneous tuning of both structural order and disorder in materials, although are important in photonics, but still remain as major challenges. In this paper, we show that optical path length dictates light-matter interaction in the same crystal structure formed by the ordering of magnetic nanoparticle self-assembled columns inside magnetic nanofluid under applied field. When the optical path length (L=80 {\mu}m) is shorter than the optical (for wavelength, {\lambda}=632.8 nm) coherence length inside the magnetic nanofluid under applied field, a Debye diffraction ring pattern is observed; while for longer path length (L=1mm), a corona ring of scattered light is observed. Analysis of Debye diffraction ring pattern suggests the formation of 3D hexagonal crystal structure, where the longitudinal and lateral inter-column spacings are 5.281 and 7.344 microns, respectively. Observation of speckles within the Debye diffraction pattern confirms the presence of certain degree of structural disorder within the crystal structure, which can be tuned by controlling the applied field strength, nanoparticle size and particle volume fraction. Our results provide a new approach to develop next generation of tunable photonic devices, based on simultaneous harnessing of the properties of disordered photonic glass and 3D photonic crystal.
Mechanized Transplanting of Rice (Oryza sativa L.) in Nonpuddled and No-Till Conditions in the Rice-Wheat Cropping System in Haryana, India  [PDF]
Baldev Raj Kamboj, Dharam Bir Yadav, Ashok Yadav, Narender Kumar Goel, Gurjeet Gill, Ram K. Malik, Bhagirath Singh Chauhan
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.412298
Abstract:

The common practice of establishing rice in the rice-wheat system in India is manual transplanting of seedlings in the puddled soil. Besides being costly, cumbersome, and time consuming, puddling results in degradation of soil and the formation of a hard pan, which impedes root growth of subsequent upland crops. In addition, decreased availability and increasing cost of labor have increased the cost of rice cultivation through conventional methods. Because of these concerns, there is a need for mechanized transplanting of rice which is less labor-intensive and can ensure optimum plant population under nonpuddled and/or no-till conditions. A large number of on-farm trials were conducted at farmers’ fields in Haryana, India, from 2006 to 2010 to evaluate the performance of the mechanical transplanted rice (MTR) under nonpuddled and no-till situations as compared to conventional puddled transplant rice (CPTR). Compared with CPTR, nonpuddled MTR produced 3%-11% higher grain yield in different years. Rice cultivars, viz. HKR47, HKR127, PR113, PR114, PB1, PB1121, CSR30, and Arize6129, performed consistently better under nonpuddled MTR as compared to CPTR. Performance of different cultivars (PR113, PR114, HKR47, and Pusa 44) was also better under no-till MTR as compared to CPTR. The basmati cultivar CSR30 performed equally in no-till MTR and CPTR systems. The results of our study suggest that rice can be easily grown under nonpuddled and no-till conditions with yield advantages over the CPTR system. Even in the case of similar yield between CPTR and MTR systems, the MTR system will help in reducing labor requirement and ultimately, will increase overall profits to farmers.

Statistical analysis of acoustic emission signals generated during turning of a metal matrix composite
Mukhopadhyay, C. K.;Jayakumar, T.;Raj, Baldev;Venugopal, S.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2012, DOI: 10.1590/S1678-58782012000200006
Abstract: acoustic emission technique (aet) has been used to monitor the progress of tool wear during turning of silicon carbide (20 wt.%) dispersed al alloy metal matrix composite. acoustic emission (ae) signals generated beyond a specific cutting distance increase abruptly. statistical analysis based on assumed β distribution of ae energy showed that skewness and kurtosis vary with cutting time. comparison of these results with bparameter of amplitude distribution of ae hits presented in an earlier investigation has shown that while b-parameter is useful for monitoring tool wear up to 0.4 mm, skewness and kurtosis can better monitor the wear beyond that. uncertainty measurement of ae energy for different cutting distances was determined as per iso gum. the combined uncertainty for the measurement of ae energy lies in the range of 0.38 to 1.69, with higher values for the cutting distance between 213.8 mm and 454.5 mm. different parameters such as skewness and kurtosis of the statistical distribution, b-parameter of amplitude distribution and uncertainties can be used in a complimentary manner for comprehensive evaluation of tool wear.
Evaluation of Mammary Cancer in 7,12-Dimethylbenz(a)anthracene-Induced Wister Rats by Asymmetrical Temperature Distribution Analysis Using Thermography: A Comparison with Serum CEA Levels and Histopathology
S. P. Angeline Kirubha,M. Anburajan,B. Venkataraman,R. Akila,D. Sharath,Baldev Raj
Journal of Biomedicine and Biotechnology , 2012, DOI: 10.1155/2012/786417
Abstract: Animal surface temperature profile captured using infrared camera is helpful for the assessment of physiological responses associated with the regulation of body temperature. Diagnosing breast cancer in early stage itself has a greater effect on the prognosis. In this work, asymmetrical temperature distribution analysis of chemical carcinogen 7,12-dimethyl benz(a)anthracene-induced in the lower right flank region of Wistar rats (=6) was carried out to test the potential of thermography in diagnosing mammary cancer and tumor growth over a period of nine weeks in comparison with histopathology results as standard. Temperature difference between the tumor induced lower right and left side of flank region was significant (with P value <0.001), whereas in the abdomen and shoulder there was no significant difference in temperature between right and left sides. Percentage of asymmetrical temperature difference in the tumor induced lower flank region was 0.5 to 2%, whereas in the other regions it was <0.5%. Green pixel distribution in RGB color histogram was asymmetrical in the tumor induced lower flank region. Temperature reduction was observed in the tumor induced region after the seventh day of carcinogen induction. Asymmetrical thermogram analysis is the best method of diagnosing mammary cancer and for studying tumor development.
EVALUATION OF GRAY INTENSITY VALUE FOR RELIABLE DIGITIZATION OF DIGITAL RADIOGRAPHY IN DEFECT DETECTION
P.Chitra,B.Sheela Rani,B.Venkatraman,Baldev Raj
International Journal of Engineering Science and Technology , 2011,
Abstract: Radiography is one of the oldest NDT technique used for evaluation of weld defects in metal. Radiographic defects are classified based on the shape, location, orientation, depth, width etc. Once a radiographof a weld is taken, the radiographer examines the same for identifying the defects and quantitatively evaluating the same based on codes and specifications. In recent years digital imaging has superseded conventional imaging, which has led to a profound change in interpretation of radiographic images. A change in the Gray values of the digital image (edges) indicates the flaws on the radiographic image. This paper discusses the Gray level distribution of a test piece radiograph. The test piece considered is a stainless steel metal plate on which a square hole is drilled with different area and depth. The plate is radiographed using X-ray and gamma rays (IR192).
Evaluation of the Signal to Noise in Different Radiographic Methods and in Standard Digitizer
P.Chitra,B.Sheela Rani,B.Venkatraman,Baldev Raj
Indian Journal of Computer Science and Engineering , 2011,
Abstract: Radiography is one of the methods to find volumetric defects in Non Destructive Technique (NDT). Radiographic film is digitized for the further assessment of the defects. The successful use of radiographydepends on the source used being X-ray or Gamma rays and the digitizer. The effect of source and digitizer used should produce necessary contrast and quality of the image. This paper deals with the different radiographic technique applied on a stainless steel pipes .The resultant radiographic film is digitized in three differentdigitizers. The variations of image quality parameters such as Signal to Noise Ratio (SNR), Memory capacity,Resolution is analyzed for the film digitized in different resolutions and file formats. The results have been analyzed to find the suitable parameters for the digitization of radiographic weld metal. The results show that X_ray source is giving good Signal to Noise Ratio compared with the other two sources.
Microstructural studies on lattice imperfections in irradiated Titanium and Ti-5%Ta-2%Nb by X-Ray Diffraction Line Profile Analysis
P. Mukherjee,A. Sarkar,P. Barat,Baldev Raj,U. Kamachi Mudali
Physics , 2005,
Abstract: The microstructural parameters like the average domain size, effective domain size at a particular crystallographic direction and microstrain within the domains of titanium and Ti-5%Ta-2%Nb, irradiated with 116 MeV O5+ ion, have been characterized as a function of dose by X-Ray Diffraction Line Profile Analysis using different model based approaches. Dislocation Density and stacking fault probabilities have also been estimated from the analysis. The analysis revealed that there was a significant decrease of the average domain size with dose as compared to the unirradiated sample. The estimated values of dislocation density increased significantly for the irradiated samples and was found to be an order of magnitude more as compared to the unirradiated one. However, the dislocation density saturated with increase in dose. The deformation (stacking) fault probabilities were found to be negligible even with the increase in dose of irradiation.
Detecting onset of chain scission and crosslinking of gamma-ray irradiated elastomer surfaces using frictional force microscopy
S. Banerjee,N. K. Sinha,N. Gayathri,D. Ponraju,S. Dash,A. K. Tyagi,Baldev Raj
Physics , 2005,
Abstract: We report here that atomic force microscope (AFM) in frictional force mode can be used to detect onset of chain scission and crosslinking in polymeric and macromolecular samples upon irradiation. A systematic investigation to detect chain scission and crosslinking of two elastomers: (1) Ethylene-propylene-diene monomer rubber (EPDM) and (2) Fluorocarbon rubber (FKM) upon gamma-ray irradiation has been carried out using frictional force microscopy (FFM). From the AFM results we observed that both the elastomers show a systematic smoothening of its surfaces, as the gamma-ray dose rate increases. However, the frictional property studied using FFM of the sample surfaces show an initial increase and then a decrease as a function of dose rate. This behavior of increase in its frictional property has been attributed to the onset of chain scission and the subsequent decrease in friction has been attributed to the onset of crosslinking of the polymer chains. The evaluated qualitative and semi-quantitative changes observed in the overall frictional property as a function of gamma-ray dose rate for the two elastomers are presented in this paper.
Conductivity landscape of highly oriented pyrolytic graphite surface containing ribbons and edges
S. Banerjee,M. Sardar,N. Gayathri,A. K. Tyagi,Baldev Raj
Physics , 2005, DOI: 10.1103/PhysRevB.72.075418
Abstract: We present an extensive study on electrical spectroscopy of graphene ribbons and edges of highly oriented pyrolytic graphite (HOPG) using atomic force microscope (AFM). We have addressed in the present study two main issues, (1) How does the electrical property of the graphite (graphene) sheet change when the graphite layer is displaced by shear forces? and (2) How does the electrical property of the graphite sheet change across a step edge? While addressing these two issues we observed, (1) variation of conductance among the graphite ribbons on the surface of HOPG. The top layer always exhibits more conductance than the lower layers, (2) two different monolayer ribbons on the same sheet of graphite shows different conductance, (3) certain ribbon/sheet edges show sharp rise in current, (4) certain ribbons/sheets on the same edge shows both presence and absense of the sharp rise in the current, (5) some lower layers at the interface near a step edge shows a strange dip in the current/conductance (depletion of charge). We discuss possible reasons for such rich conducting landscape on the surface of graphite.
Deformation potential dominated phonons in ZnS quantum dots
S. Dhara,A. K. Arora,Jay Ghatak,K. H. Chen,C. P. Liu,L. C. Chen,Y. Tzeng,Baldev Raj
Physics , 2007,
Abstract: Strong deformation potential (DP) dominated Raman spectra are reported for quantum confined cubic ZnS nanoclusters under off-resonance conditions allowed only in quantum dots. A flurry of zone boundary phonons is demonstrated in the scattering process. Transverse optic (TO) mode in the multi-phonon process shows only even order overtones suggesting the dominance of a two-phonon process (having large DP value in ZnS) and its integral multiples. Two-phonon TO modes corresponding to A1 and B2 symmetries are also demonstrated under off-resonance conditions which are allowed only in quantum dots.
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