Pramod Kumar | C-DAC (formerly NCST) (original) (raw)

Drafts by Pramod Kumar

Research paper thumbnail of Spotlight

Papers by Pramod Kumar

Research paper thumbnail of Effect of γ-irradiation on oxygen content and kinetic parameters of high Tc Y1Ba2Cu3O7−δ superconductors

Materials Chemistry and Physics, 2006

The effect of γ-irradiation on oxygen content and kinetic parameters of high temperature ceramic ... more The effect of γ-irradiation on oxygen content and kinetic parameters of high temperature ceramic Y1Ba2Cu3O7−δ (YBCO) superconductor have been investigated. The bulk samples prepared by the standard solid-state method were irradiated by γ-rays of different dose in the range of 5.04×103 to 4.23×107 (R) at room temperature. The effects of irradiation on surface morphology viz. grain size, porosity and the

Research paper thumbnail of Carbon nanotube tip melting with vacuum breakdown in cold cathode

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2007

Failure of patterned multiwalled carbon nanotubes during field emission (FE) was systematically s... more Failure of patterned multiwalled carbon nanotubes during field emission (FE) was systematically studied at different fields using an indigenous FE setup. Here, the findings are reported from the experimental observation of the degradation of carbon nanotube (CNT) ...

Research paper thumbnail of S-100 protein release in a range of cardiothoracic surgical procedures

The Journal of Thoracic and Cardiovascular Surgery, 1997

Research paper thumbnail of Establishing SCS Runoff Curve Number from IRS Digital Data Base

Journal of the Indian Society of Remote Sensing, 1991

ABSTRACT

Research paper thumbnail of Correlation of AM spore number, percent root colonization and Azotobacter count with plant growth, fruit yield and leaf nutrient content of Royal Delicious apple

Environment and Ecology, 2009

Research paper thumbnail of Discrimination of newly planted and ratoon crops of sugar cane using multidate IRS-1C liss III data: A knowledge based approach

Journal of the Indian Society of Remote Sensing, 2000

Research paper thumbnail of Studies on AM colonization in soils of apple orchards of North-Western Himalayan Region

Asian Journal of Horticulture, 2007

Research paper thumbnail of Rice-acreage estimation for Orrisa using remotely sensed data

Journal of the Indian Society of Remote Sensing, 1991

Research paper thumbnail of A Novel Lowpass Filter with Sharp Transition of Wide Stopband and Improved Q-Factor Performance Using Hexagonal Defected Ground structure (DGS)”

Research paper thumbnail of Satellite stereo data for dem surfaces and derivatives

Journal of the Indian Society of Remote Sensing, 2004

Various attributes can be derived from Digital Elevation Model (DEM), which are essential to anal... more Various attributes can be derived from Digital Elevation Model (DEM), which are essential to analyze watershed physical characteristics. This paper discusses utility and accuracy of satellite DEM surfaces and their derivatives. Facilities available in various software packages ...

Research paper thumbnail of Surface impedance concept and its application to electromagnetic guided wave propagation

Some problems are considered in electromagnetic theory where the surface impedance concept has be... more Some problems are considered in electromagnetic theory where the surface impedance concept has been applied to guided wave propagation. In Chapter 1, an extensive study of the relevant literature was reviewed and analyzed in detail. Propagation between two parallel planes with two impedances suggests many more possibilities. In Chapter 2, the problems pertaining to propagation between two parallel planes is discussed in detail. In Chapter 3, analysis of the modes in cylindrical domain with reactive impedance wall is made. In Chapter 4 first some of the important work on periodic structure was analyzed and reviewed. In Chapter 5, several propagation characteristics associated with modes in cylindrical structure with constant surface impedance and when the surface impedance is a function of wave number are computed.

Research paper thumbnail of Measurement of pressure effects on the magnetic and the magnetocaloric properties of the intermetallic compounds DyCo 2 and Er(Co 1− x Si x ) 2

Journal of Physics: Condensed Matter, 2007

The effect of external pressure on the magnetic properties and magnetocaloric effect of R(Co 1-x ... more The effect of external pressure on the magnetic properties and magnetocaloric effect of R(Co 1-x Si x ) 2 [R= Er, Dy and x=0, 0.025 and 0.05] compounds has been studied. The ordering temperatures of both the parent as well as the Si substituted compounds are found to decrease with pressure. In all the compounds, the critical field for metamagnetic transition increases with pressure. It is seen that the magnetocaloric effect in the parent compounds is almost insensitive to pressure, while there is considerable enhancement in the case of Si substituted compounds. Spin fluctuations arising due to the magnetovolume effect play a crucial role in determining the pressure dependence of magnetocaloric effect in these compounds. Analysis of the magnetization data using the Landau theory has shown that the magnitude of the Landau coefficient (C 3 ) decreases with Si concentration whereas it is found to increase with pressure. The isothermal magnetic entropy change is found to behave in the same manner as C 3 , both with Si concentration (at ambient pressure) as well as with the applied pressure.

Research paper thumbnail of Optical probing of long range spatial correlation and symmetry in complex biophotonic architectures in the transparent insect wings

We experimentally probe complex bio-photonic architecture of microstructures on the transparent i... more We experimentally probe complex bio-photonic architecture of microstructures on the transparent insect wings by a simple, non-invasive, real time optical technique. A stable and reproducible far-field diffraction pattern in transmission was observed using collimated cw and broadband fs pulses. A quantitative analysis of the observed diffraction pattern unveiled a new form of long-range semi-periodic order of the microstructures over mm scale. These observations agree well with Fourier analysis of SEM images of the wing taken at various length scales. We propose a simple quantitative model based on optical diffraction by an array of non-overlapping microstructures with minimal disorder which supports our experimental observations. Two different applications of our techniques are demonstrated. First, by scanning the laser beam across the wing sample we observed a rotation of the original diffraction profile which gives direct signature of organizational symmetry of microstructures. Second, we report the first optical detection of reorganization in the photonic architecture on the Drosophila wings by various genetic mutations. These results have potentials for design and development of diffractive optical components for applications and identifying routes to genetic control of biomemetic devices.

Research paper thumbnail of Magnetic, magnetocaloric and magnetoresistance properties of Nd 7 Pd 3

Journal of Physics: Condensed Matter, 2009

Magnetic, magnetocaloric and magnetoresistance properties of the intermetallic compound Nd 7 Pd 3... more Magnetic, magnetocaloric and magnetoresistance properties of the intermetallic compound Nd 7 Pd 3 have been investigated. It exhibits a first-order magnetic phase transition at its ferromagnetic ordering temperature (T C = 34 K). Just above the T C , the magnetization isotherms exhibit a metamagnetic transition from the paramagnetic to a ferromagnetic state. In the immediate vicinity of T C , a field change of only 10 kOe leads to the giant magnetocaloric effect of 13 J mol −1 K −1 . For a field change of 50 kOe a large magnetoresistance of ∼21% is observed near T C . First-principles electronic structure calculations indicate that the first-order phase transition in Nd 7 Pd 3 may originate from the peculiar nature of the density of states near the Fermi level.

Research paper thumbnail of Phytobezoar with gastric ulcer

Indian Journal of Gastroenterology

Research paper thumbnail of Multiple magnetic transitions and the magnetocaloric effect in Gd 1− x Sm x Mn 2 Ge 2 compounds

Journal of Physics: Condensed Matter, 2007

Magnetic and magnetocaloric properties of polycrystalline samples of Gd 1-

Research paper thumbnail of ISE.130- Limited Access Dressing (LAD) Design

Chlamydia pneumoniae pneumonia contains 7.4% of bacterial pneumonia and 5% of all pneumonia cases... more Chlamydia pneumoniae pneumonia contains 7.4% of bacterial pneumonia and 5% of all pneumonia cases. This rate is almost high but in contrast to western countries is on lower level.

Research paper thumbnail of Magnetic and magnetocaloric effect in melt spun La 1− x R x Fe 13− y Al y C z ( R = Pr and Nd) compounds

Journal of Physics D: Applied Physics, 2009

In this paper, we report the structural, magnetic and magnetocaloric effect (MCE) of La 1− x R x ... more In this paper, we report the structural, magnetic and magnetocaloric effect (MCE) of La 1− x R x Fe 13− y Al y C z (R= Pr and Nd, x= 0.1 and 0.2, y= 1.5 and 1.6 and z= 0.02 and 0.04) compounds. Temperature dependence of magnetization data shows second order and ...

Research paper thumbnail of LAD Trauma Protocol

Research paper thumbnail of Effect of γ-irradiation on oxygen content and kinetic parameters of high Tc Y1Ba2Cu3O7−δ superconductors

Materials Chemistry and Physics, 2006

The effect of γ-irradiation on oxygen content and kinetic parameters of high temperature ceramic ... more The effect of γ-irradiation on oxygen content and kinetic parameters of high temperature ceramic Y1Ba2Cu3O7−δ (YBCO) superconductor have been investigated. The bulk samples prepared by the standard solid-state method were irradiated by γ-rays of different dose in the range of 5.04×103 to 4.23×107 (R) at room temperature. The effects of irradiation on surface morphology viz. grain size, porosity and the

Research paper thumbnail of Carbon nanotube tip melting with vacuum breakdown in cold cathode

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2007

Failure of patterned multiwalled carbon nanotubes during field emission (FE) was systematically s... more Failure of patterned multiwalled carbon nanotubes during field emission (FE) was systematically studied at different fields using an indigenous FE setup. Here, the findings are reported from the experimental observation of the degradation of carbon nanotube (CNT) ...

Research paper thumbnail of S-100 protein release in a range of cardiothoracic surgical procedures

The Journal of Thoracic and Cardiovascular Surgery, 1997

Research paper thumbnail of Establishing SCS Runoff Curve Number from IRS Digital Data Base

Journal of the Indian Society of Remote Sensing, 1991

ABSTRACT

Research paper thumbnail of Correlation of AM spore number, percent root colonization and Azotobacter count with plant growth, fruit yield and leaf nutrient content of Royal Delicious apple

Environment and Ecology, 2009

Research paper thumbnail of Discrimination of newly planted and ratoon crops of sugar cane using multidate IRS-1C liss III data: A knowledge based approach

Journal of the Indian Society of Remote Sensing, 2000

Research paper thumbnail of Studies on AM colonization in soils of apple orchards of North-Western Himalayan Region

Asian Journal of Horticulture, 2007

Research paper thumbnail of Rice-acreage estimation for Orrisa using remotely sensed data

Journal of the Indian Society of Remote Sensing, 1991

Research paper thumbnail of A Novel Lowpass Filter with Sharp Transition of Wide Stopband and Improved Q-Factor Performance Using Hexagonal Defected Ground structure (DGS)”

Research paper thumbnail of Satellite stereo data for dem surfaces and derivatives

Journal of the Indian Society of Remote Sensing, 2004

Various attributes can be derived from Digital Elevation Model (DEM), which are essential to anal... more Various attributes can be derived from Digital Elevation Model (DEM), which are essential to analyze watershed physical characteristics. This paper discusses utility and accuracy of satellite DEM surfaces and their derivatives. Facilities available in various software packages ...

Research paper thumbnail of Surface impedance concept and its application to electromagnetic guided wave propagation

Some problems are considered in electromagnetic theory where the surface impedance concept has be... more Some problems are considered in electromagnetic theory where the surface impedance concept has been applied to guided wave propagation. In Chapter 1, an extensive study of the relevant literature was reviewed and analyzed in detail. Propagation between two parallel planes with two impedances suggests many more possibilities. In Chapter 2, the problems pertaining to propagation between two parallel planes is discussed in detail. In Chapter 3, analysis of the modes in cylindrical domain with reactive impedance wall is made. In Chapter 4 first some of the important work on periodic structure was analyzed and reviewed. In Chapter 5, several propagation characteristics associated with modes in cylindrical structure with constant surface impedance and when the surface impedance is a function of wave number are computed.

Research paper thumbnail of Measurement of pressure effects on the magnetic and the magnetocaloric properties of the intermetallic compounds DyCo 2 and Er(Co 1− x Si x ) 2

Journal of Physics: Condensed Matter, 2007

The effect of external pressure on the magnetic properties and magnetocaloric effect of R(Co 1-x ... more The effect of external pressure on the magnetic properties and magnetocaloric effect of R(Co 1-x Si x ) 2 [R= Er, Dy and x=0, 0.025 and 0.05] compounds has been studied. The ordering temperatures of both the parent as well as the Si substituted compounds are found to decrease with pressure. In all the compounds, the critical field for metamagnetic transition increases with pressure. It is seen that the magnetocaloric effect in the parent compounds is almost insensitive to pressure, while there is considerable enhancement in the case of Si substituted compounds. Spin fluctuations arising due to the magnetovolume effect play a crucial role in determining the pressure dependence of magnetocaloric effect in these compounds. Analysis of the magnetization data using the Landau theory has shown that the magnitude of the Landau coefficient (C 3 ) decreases with Si concentration whereas it is found to increase with pressure. The isothermal magnetic entropy change is found to behave in the same manner as C 3 , both with Si concentration (at ambient pressure) as well as with the applied pressure.

Research paper thumbnail of Optical probing of long range spatial correlation and symmetry in complex biophotonic architectures in the transparent insect wings

We experimentally probe complex bio-photonic architecture of microstructures on the transparent i... more We experimentally probe complex bio-photonic architecture of microstructures on the transparent insect wings by a simple, non-invasive, real time optical technique. A stable and reproducible far-field diffraction pattern in transmission was observed using collimated cw and broadband fs pulses. A quantitative analysis of the observed diffraction pattern unveiled a new form of long-range semi-periodic order of the microstructures over mm scale. These observations agree well with Fourier analysis of SEM images of the wing taken at various length scales. We propose a simple quantitative model based on optical diffraction by an array of non-overlapping microstructures with minimal disorder which supports our experimental observations. Two different applications of our techniques are demonstrated. First, by scanning the laser beam across the wing sample we observed a rotation of the original diffraction profile which gives direct signature of organizational symmetry of microstructures. Second, we report the first optical detection of reorganization in the photonic architecture on the Drosophila wings by various genetic mutations. These results have potentials for design and development of diffractive optical components for applications and identifying routes to genetic control of biomemetic devices.

Research paper thumbnail of Magnetic, magnetocaloric and magnetoresistance properties of Nd 7 Pd 3

Journal of Physics: Condensed Matter, 2009

Magnetic, magnetocaloric and magnetoresistance properties of the intermetallic compound Nd 7 Pd 3... more Magnetic, magnetocaloric and magnetoresistance properties of the intermetallic compound Nd 7 Pd 3 have been investigated. It exhibits a first-order magnetic phase transition at its ferromagnetic ordering temperature (T C = 34 K). Just above the T C , the magnetization isotherms exhibit a metamagnetic transition from the paramagnetic to a ferromagnetic state. In the immediate vicinity of T C , a field change of only 10 kOe leads to the giant magnetocaloric effect of 13 J mol −1 K −1 . For a field change of 50 kOe a large magnetoresistance of ∼21% is observed near T C . First-principles electronic structure calculations indicate that the first-order phase transition in Nd 7 Pd 3 may originate from the peculiar nature of the density of states near the Fermi level.

Research paper thumbnail of Phytobezoar with gastric ulcer

Indian Journal of Gastroenterology

Research paper thumbnail of Multiple magnetic transitions and the magnetocaloric effect in Gd 1− x Sm x Mn 2 Ge 2 compounds

Journal of Physics: Condensed Matter, 2007

Magnetic and magnetocaloric properties of polycrystalline samples of Gd 1-

Research paper thumbnail of ISE.130- Limited Access Dressing (LAD) Design

Chlamydia pneumoniae pneumonia contains 7.4% of bacterial pneumonia and 5% of all pneumonia cases... more Chlamydia pneumoniae pneumonia contains 7.4% of bacterial pneumonia and 5% of all pneumonia cases. This rate is almost high but in contrast to western countries is on lower level.

Research paper thumbnail of Magnetic and magnetocaloric effect in melt spun La 1− x R x Fe 13− y Al y C z ( R = Pr and Nd) compounds

Journal of Physics D: Applied Physics, 2009

In this paper, we report the structural, magnetic and magnetocaloric effect (MCE) of La 1− x R x ... more In this paper, we report the structural, magnetic and magnetocaloric effect (MCE) of La 1− x R x Fe 13− y Al y C z (R= Pr and Nd, x= 0.1 and 0.2, y= 1.5 and 1.6 and z= 0.02 and 0.04) compounds. Temperature dependence of magnetization data shows second order and ...

Research paper thumbnail of LAD Trauma Protocol

Research paper thumbnail of Large reversible magnetocaloric effect in RNi compounds

Journal of Physics D: Applied Physics, 2008

In an attempt to identify novel magnetic refrigerant materials, we have studied the magnetic and ... more In an attempt to identify novel magnetic refrigerant materials, we have studied the magnetic and magnetocaloric properties in RNi compounds with R = Gd, Ho and Er. GdNi is a simple ferromagnet with a collinear structure in contrast to HoNi and ErNi, in which the moments of rare earth sublattice are arranged non-collinearly. The magnetic ordering temperatures are observed to be 69 K, 36.5 K and 10 K for GdNi, HoNi and ErNi, respectively. The maximum values of magnetocaloric effect ( S max M ) are found to be 17 J kg −1 K −1 , 15 J kg −1 K −1 and 29 J kg −1 K −1 for Gd, Ho and Er, respectively, for an applied field of 50 kOe. The relative cooling power has been calculated to be 527 J kg −1 K −1 , 780 J kg −1 K −1 and 510 J kg −1 K −1 for GdNi, HoNi and ErNi. These values compare well with those of many potential materials whose magnetic transitions are in the same range as in the present case.