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Search Results: 1 - 10 of 3741 matches for " Anand Pal "
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Performance Enhancement of the Proton Exchange Membrane Fuel Cell Using Pin Type Flow Channel with Porous Inserts  [PDF]
Vaibhav Pal, P. Karthikeyan, R. Anand
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.35001
Abstract: The design of the flow field is highly responsible for the performance of the Proton Exchange Membrane Fuel Cell (PEMFC). In this study, pin type flow channel is numerically analyzed by arranging carbon made porous material in uniform and zigzag manner on the rib surface of the flow field. The study focuses on enhancing the performance of PEMFC by reducing liquid flooding in the interface between the rib and Gas Diffusion Layer (GDL). A single PEMFC having an active area of 25 cm2, with three flow channel designs (conventional serpentine, pin type flow channel with 2 mm cubical porous inserts in zigzag and uniform pattern) are modeled for the numerical analysis. The effect of porosity of the carbon inserts on the cell performance is studied by varying its value from 0.6 to 0.9. The results show that the performance of the flow channel with zigzag and uniformly positioned porous inserts is more than the conventional serpentine flow channel by 20.36% and 16.87% respectively. The reason for this increase is the removal of the accumulated water from the rib surface due to the capillary action of the porous carbon inserts. This helps in eliminating the stagnant water regions under the rib and thereby helps in reducing liquid flooding.
Secure Spread-Spectrum Watermarking for Telemedicine Applications  [PDF]
Basant Kumar, Harsh Vikram Singh, Surya Pal Singh, Anand Mohan
Journal of Information Security (JIS) , 2011, DOI: 10.4236/jis.2011.22009
Abstract: This paper presents a secure spread-spectrum watermarking algorithm for digital images in discrete wavelet transform (DWT) domain. The algorithm is applied for embedding watermarks like patient identification /source identification or doctors signature in binary image format into host digital radiological image for potential telemedicine applications. Performance of the algorithm is analysed by varying the gain factor, subband decomposition levels, size of watermark, wavelet filters and medical image modalities. Simulation results show that the proposed method achieves higher security and robustness against various attacks.
Effect of Co-doping on the resistivity and thermopower of SmFe1-xCoxAsO (0.0≤x≤0.3)
Gunadhor S. Okram,Netram Kaurav,Ajay Soni,Anand Pal
AIP Advances , 2012, DOI: 10.1063/1.4766936
Abstract: We report structure, electrical resistivity and thermopower of polycrystalline SmFe1-x CoxAsO samples for 0.0 ≤ x ≤ 0.3. The XRD data revealed full Co substitution at Fe-site with slight compression of the unit cell. Resistivity data showed that the spin-density wave observed at 130 K for x = 0 is suppressed when x = 0.05, above which superconductivity emerges due to injection of mobile electrons, supporting the substitution of Co3+ at Fe2+ site but disappears for x = 0.3. The thermopower (S) data indicate that the majority of charge carriers is electron-like and its value reaches 81 μV/K (at 300 K) for x = 0.3. Noticeable deviations from the expected linear behavior in S(T) at low temperatures and S/T against temperature curves at intermediate temperatures were observed. These observations were interpreted on the basis of nested Fermi surface and Umklapp processes.
Vaibhav Shukla,Ankit Anand Kharia,Indu Pal Kaur
Journal of Pharmaceutical and Scientific Innovation , 2012,
Abstract: Diltiazem HCl (DTZ) is an antihypertensive agent that antagonizes the action of beta-1 receptor. DTZ when given orally is well absorbed from the gastrointestinal tract and is subject to an extensive first-pass effect. DTZ undergoes extensive metabolism in which only 2% to 4% of the unchanged drug appears in the urine. Drugs which induce or inhibit hepatic microsomal enzymes may alter DTZ disposition. It has been reported that the absolute bioavailability of DTZ when given orally is 30-40%. The biological half-life of DTZ is 4-6 hour and the main site of absorption is proximal small intestine.The reduced bioavailability of DTZ may be because of transportation of dosage form from the region of absorption window to site where it is less absorbed. Therefore there was a need to increase gastroretention time of dosage form so that drug would be available at the site of absorption and results in improved bioavailability. A mucoadhesive nanoparticle delivery system was envisioned for DTZ as such a system when administered would adhere on the gastric mucosa for a prolong period of time and the drug would be available at the main site of absorption i.e. proximal small intestine resulting in enhanced bioavailability.
Synthesis and Structural details of BiOCu1-xS: Possible new entrant in series of exotic superconductors?
Anand Pal,H. Kishan,V. P. S. Awana
Physics , 2009,
Abstract: We report an easy route single step synthesis of BiOCuS with and without Cu deficiency. The title compound is synthesized via solid state reaction route by encapsulation in an evacuated (10-3 Torr) quartz tube. Mixed components of the ingredients in stoichiometric ratio (1/3Bi2O3 +0.34Bi +Cu1-x + S) are pelletized, sealed in evacuated quartz tube and heat treated for 30 hours at 500 0C. Finally the sample is allowed to cool down to room temperature. The resultant compound is black is color and could not hold in pellet form, but is powdered. X-ray diffraction Reitveld analysis is carried out on all three samples of series BiOCu1-xS with x = 0.0, 0.10 and 0.15. These samples crystallize in single phase with space group P4/nmm and with cell parameters as a = 3.868 A and c = 8.557 A for stoichiometric BiOCuS. The volume of the cell slightly increases with an increase in Cu deficiency. The co-ordinate positions are determined by fitting the observed XRD patterns of the studied samples.
Possible kinetic arrest of the ferromagnetic to anti-ferromagnetic transition in SmCoAsO: The interplay of Sm4f and Co3d spins
Anand Pal,H. Kishan,V. P. S. Awana
Physics , 2010,
Abstract: The article is withdrawn and its revised version will be submitted later.
High field magneto-transport study of YBa2Cu3O7-Agx (x = 0.0 to 0.20)
Poonam Rani,Anand Pal,V. P. S Awana
Physics , 2013, DOI: 10.1016/j.physc.2013.10.008
Abstract: We report high field (up to 13 Tesla) magneto transport R(T)H] of YBa2Cu3O7 (YBCO):Agx (x= 0.0, 0.1 and 0.2) composites. The transport properties are significantly improved by Ag doping on the insulating grain boundaries of YBCO. Pure and Ag diffused YBCO superconducting samples are synthesized through solid state reaction route. Both pure and Ag doped YBCO are superconducting at below 90K. Though, the Tc (R=0) of YBCO:Ag samples under applied field of 13 Tesla is around 65K, the same is 45K for pure YBCO under same applied field. The upper critical field [Hc2(0)], being estimated from R(T)H is around 70Tesla for pristine sample, and is above 190Tesla for Ag doped samples. The boarding of the resistive transition under applied magnetic field is comparatively less and nearly single step for Ag doped samples, while the same is clearly two step and relatively much larger for the pristine YBCO. The resistive broadening is explained on the basis of changed inter-granular coupling and thermally activated flux flow (TAFF). The TAFF activation energy (U0) is found to be linear with applied magnetic field for all the samples, but with nearly an order of magnitude less value for the Ag doped samples. Summarily, it is shown that inclusion of Ag significantly improves the superconducting performance of YBCO:Ag composites, in particular under applied field.
Anomalous magnetism of Pr in PrCoAsO
Brajesh Tiwari,Anand Pal,V. P. S. Awana
Physics , 2014,
Abstract: Detailed magnetization and magneto-transport measurements studies are carried out to unearth the anomalous magnetism of Pr in PrCoAsO compound. The studied PrCoAsO sample is single phase and crystallized in the tetragonal structure with space group P4/nmm in analogy of ZrCuSiAs type compounds. Detailed magnetization measurements showed that Co moments in PrCoAsO exhibit weakly itinerant ferromagnetic Co spins ordering at below 80 K with a small magnetic moments of 0.12 muB/f.u. High temperatures Curie-Weiss fit, resulted in effective paramagnetic moment mueff (exp) of 5.91 muB/f.u., which can be theoretically assigned to 3d Co (3.88 muB) and 4f Pr (3.58 muB). Further, a positive Curie- Weiss temperature of 136 K is seen, indicating predominant ferromagnetic interactions in PrCoAsO. Detailed transport measurements showed that PrCoAsO exhibit metallic behavior and negative magneto-resistance below ferro-magnetically (FM) ordered state. Surprisingly, the situation of PrCoAsO is similar to non magnetic La containing LaCoAsO and strikingly different than that as reported for magnetic Nd, Sm and Gd i.e., (Nd/Sm/Gd)CoAsO. The magnetic behavior of PrCoAsO being closed to LaCoAsO and strikingly different to that of (Nd/Sm/Gd)CoAsO is unusual.
Evolution of superconductivity in PrFe1-xCoxAsO with x = 0.0 to 1.0
Poonam Rani,Anand Pal,V. P. S. Awana
Physics , 2014, DOI: 10.1016/j.ssc.2014.02.006
Abstract: We report the synthesis and physical property characterization of PrFe1-xCoxAsO with x = 0.0 to 1.0. The studied samples are synthesized by solid state reaction route via vacuum encapsulation method. The pristine compound PrFeAsO does not show superconductivity, but rather exhibits a metallic step like transition due to spin density wave ordering of Fe moments below 150 K, followed by another upward step due to anomalous ordering of Pr moments at 12 K. Both the Fe-SDW and Pr-TN temperatures decrease monotonically with Co substitution at Fe site. Superconductivity appears in a narrow range of x from 0.07 to 0.25 with maximum Tc at 11.12 K for x = 0.15. Samples, with x = 0.25 exhibit metallic behavior right from 300 K down to 2 K, without any Fe-SDW or Pr-TN steps in resistivity. In fact, though Fe-SDW decreases monotonically, the Pr-TN is disappeared even with x = 0.02. The magneto transport measurements below 14 Tesla on superconducting polycrystalline Co doped PrFeAsO lead to extrapolated values of the upper critical fields [Hc2(0)] of up to 60 Tesla.
Appearance and disappearance of superconductivity with Fe site Co substitution in SmFe1-xCoxAsO (x = 0.0 to 1.0)
V. P. S. Awana,Anand Pal,Mushahid Hussain,H. Kishan
Physics , 2010,
Abstract: We report synthesis, structural details and magnetization of SmFe1-xCoxAsO with x ranging from 0.0 to 1.0 at close interval of 0.10. It is found that Co substitutes fully at Fe site in SmFeAsO in an iso-structural lattice with slightly compressed cell. The parent compound exhibited known spin density wave (SDW) character below 150K. Successive doping of Co at Fe site suppressed the SDW transition for x = 0.05 and later induced superconductivity for x = 0.10, 0.15 and 0.20 respectively at 14, 15.5 and 9K. The appearance of bulk superconductivity is established by wide open isothermal magnetization M(H) loops. For higher content of Co i.e. x \geq 0.30, superconductivity is not observed. Clearly the Co substitution at Fe site in SmFe1-xCoxAsO diminishes the Fe SDW character (x=0.05), introduces bulk superconductivity for x from 0.10 to 0.20 and finally becomes a non-superconductor. The SmCoAsO also exhibits a secondary AFM like transition at below around 50 K. The reported AFM ordering of Sm spins is seen from heat capacity Cp(T) at 4.5 K and the same remains invariant with Co doping in SmFe1-xCoxAsO. Further the FM ordering of Co-spins (seen in magnetization measurements) is not evident in Cp(T) studies, suggesting weak correlations between ordered Co-spins in these systems.
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