308 results on '"Das, J."'
Search Results
2. Recent Developments on Brønsted Acid Catalyzed Asymmetric Aldol Reactions and the Fate of the Catalysts.
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Das, J.
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BRONSTED acids , *ORGANOCATALYSIS , *SILYL enol ethers , *ALDOLS , *ACID catalysts , *CATALYSTS , *LEWIS acids - Abstract
Since the innovative work of Terada and Akiyama, asymmetric reaction using chiral Brønsted acid has attracted great attention. Asymmetric aldol reactions are extensively studied in different organocatalysis. Brønsted acid-catalyzed aldol reaction may be carried out directly without modification of the substrates or Mukaiyama type aldol reaction using silyl enol ether as nucleophiles. The reaction may proceed through the formation of enol intermediate followed by the attack to the electrophile while Mukaiyama type aldol reactions may follow two mechanistic pathways-Brønsted acidic pathways where Brønsted acid directly activates the substrate or Lewis acid pathways where Brønsted acid acts as precatalyst. Here, the recent advancement of asymmetric aldol reactions using chiral Brønsted acid as a catalyst and the fate of the catalysts in the reaction has been discussed in this review. It is observed that some kinds of aldol reactions have rarely been studied and need more attention. [ABSTRACT FROM AUTHOR]
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- 2023
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3. Model-Based Single-Fault Disambiguation Using Temporal Information and Genetic Algorithm: A Case Study on Hydraulic Drive System.
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Kumar, Sawan, Ghoshal, Sanjoy K., and Das, J.
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HYDRAULIC drive , *HYDRAULIC machinery , *TORQUE , *BUILDING sites , *PARAMETER estimation - Abstract
In this article, a special type of fault isolation problem is reported where temporal information is required for the estimation of parameters from susceptible fault sub-space. Any physical system always obeys certain mathematical constraints under the normal operating condition, and that is incorporated in a behavioral model, which is essentially flowing and force or moment balance. In a fault detection and identification (FDI) model, only concurrent states are known. In FDI, the constraint relationships need to be derived only in terms of known variables, i.e., the measurements and nominal parameters, which are termed analytical redundancy relations (ARRs). The numerical evaluation of ARRs is residuals, and those oscillate within a definite bound of error when computed using test data. In this work, a novel function is formulated using the ARRs at different time instants and that function is minimized to estimate the suspected parameter values belonging to the non-isolable sub-space. Single-fault hypothesis is considered, and a genetic algorithm (GA) is used for the optimization. This FDI analysis may be beneficial for power hydraulic-driven heavy machinery such as hydraulic excavators, dumpers, and front-end loaders, which are mostly used in mines and construction sites. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Autologous haematopoietic stem cell transplantation as a first-line disease-modifying therapy in patients with 'aggressive' multiple sclerosis.
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Das, J, Snowden, JA, Burman, J, Freedman, MS, Atkins, H, Bowman, M, Burt, RK, Saccardi, R, Innocenti, C, Mistry, S, Laud, PJ, Jessop, H, and Sharrack, B
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HEMATOPOIETIC stem cell transplantation , *MAGNETIC resonance imaging , *MULTIPLE sclerosis - Abstract
Background: Autologous haematopoietic stem cell transplantation (AHSCT) is an effective treatment for patients with multiple sclerosis (MS) who have highly active disease, despite the use of standard disease-modifying therapies (DMTs). However, the optimal time for offering AHSCT to patients with 'aggressive' MS is yet to be established. Objectives: The objective was to explore the safety and efficacy of AHSCT as a first-line DMT in patients with 'aggressive' MS. Methods: All patients with 'aggressive' MS who received AHSCT as a first-line DMT in five European and North American centres were retrospectively evaluated. Results: Twenty patients were identified. The median interval between diagnosis and AHSCT was 5 (1–20) months. All had multiple poor prognostic markers with a median pre-transplant Expanded Disability Status Scale (EDSS) score of 5.0 (1.5–9.5). After a median follow-up of 30 (12–118) months, the median EDSS score improved to 2.0 (0–6.5, p < 0.0001). No patient had further relapses. Three had residual magnetic resonance imaging (MRI) disease activities in the first 6 months post-transplant, but no further new or enhancing lesions were observed in subsequent scans. Conclusion: AHSCT is safe and effective as a first-line DMT in inducing rapid and sustained remission in patients with 'aggressive' MS. [ABSTRACT FROM AUTHOR]
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- 2021
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5. Genome-wide identification and expression analysis of the plant specific LIM genes in Gossypium arboreum under phytohormone, salt and pathogen stress.
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Raghavendra, K. P., Das, J., Kumar, R., Gawande, S. P., Santosh, H. B., Sheeba, J. A., Kranthi, S., Kranthi, K. R., and Waghmare, V. N.
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PLANT hormones , *PATHOGENIC microorganisms , *PLANT species , *ZINC-finger proteins , *ABSCISIC acid - Abstract
Asiatic cotton (Gossypium arboreum) cultivated as 'desi cotton' in India, is renowned for its climate resilience and robustness against biotic and abiotic stresses. The genome of G. arboreum is therefore, considered as a valued reserve of information for discovering novel genes or gene functions for trait improvements in the present context of cotton cultivation world-wide. In the present study, we carried out genome-wide analysis of LIM gene family in desi cotton and identified twenty LIM domain proteins (GaLIMs) which include sixteen animals CRP-like GaLIMs and four plant specific GaLIMs with presence (GaDA1) or absence (GaDAR) of UIM (Ubiquitin Interacting Motifs). Among the sixteen CRP-like GaLIMs, eleven had two conventional LIM domains while, five had single LIM domain which was not reported in LIM gene family of the plant species studied, except in Brassica rapa. Phylogenetic analysis of these twenty GaLIM proteins in comparison with LIMs of Arabidopsis, chickpea and poplar categorized them into distinct αLIM1, βLIM1, γLIM2, δLIM2 groups in CRP-like LIMs, and GaDA1 and GaDAR in plant specific LIMs group. Domain analysis had revealed consensus [(C-X2-C-X17-H-X2-C)-X2-(C-X2-C-X17-C-X2-H)] and [(C-X2-C-X17-H-X2-C)-X2-(C-X4-C-X15-C-X2-H)] being conserved as first and/or second LIM domains of animal CRP-like GaLIMs, respectively. Interestingly, single LIM domain containing GaLIM15 was found to contain unique consensus with longer inter-zinc-motif spacer but shorter second zinc finger motif. All twenty GaLIMs showed variable spatio-temporal expression patterns and accordingly further categorized into distinct groups of αLIM1, βLIM1, γLIM2 δLIM2 and plant specific LIM (DA1/DAR). For the first time, response of GaDA1/DAR under the influence of biotic and abiotic stresses were studied in cotton, involving treatments with phytohormones (Jasmonic acid and Abscisic acid), salt (NaCl) and wilt causing pathogen (Fusarium oxysporum). Expressions patterns of GaDA1/DAR showed variable response and identified GaDA2 as a probable candidate gene for stress tolerance in G. arboreum. [ABSTRACT FROM AUTHOR]
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- 2021
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6. Underfrequency and Undervoltage Load Shedding in an Industrial Plant With Cogeneration Facilities.
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Das, J. C. and McPhee, Aaron A.
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FACTORIES , *ABSCISSION (Botany) , *COGENERATION of electric power & heat , *TURBINE blades , *STEAM-turbines , *DIESEL electric power-plants - Abstract
Underfrequency load shedding is commonly used in the utility systems when AGC (Automatic Generation Control) cannot keep pace with the load demand and the stability of the generators can be jeopardized—undue stresses can be imposed on steam turbine blades. For an industrial system the underfrequency load shedding may have to be resorted to on loss of a source, to restore load-generation balance and prevent Undervoltages in the distribution system. It is documented that as long as the utility source is connected, there may not be any significant change in the frequency. This is because the plant generators, which are relatively small, cannot dictate the system frequency when operating in synchronism. Undervoltage load shedding can be resorted to. In both case the stability and frequency recovery characteristics of the generators must be studied. [ABSTRACT FROM AUTHOR]
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- 2020
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7. Effect of Moist Air and Minor Zr Addition on Oxidation Behavior of Arc-Melted Multiphase Mo–Si–B Alloys in the Temperature Range of 1000 °C–1300 °C.
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Kumar, N. K., Das, J., and Mitra, R.
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KIRKENDALL effect , *MOLYBDENUM disilicide , *ALLOYS , *OXIDATION , *AIR , *SCANNING electron microscopy , *METALLIC glasses - Abstract
Arc-melted multiphase intermetallic alloys, Mo76Si14B10, Mo74Si14B10Zr2, Mo79.5Si12B8.5 and Mo77.5Si12B8.5Zr2 with microstructures containing Moss, Mo3Si and Mo5SiB2 were isothermally exposed for 1 h or 24 h at 1000 °C, 1150 °C and 1300 °C in dry or moist air. The residual area fraction was found to be the highest on exposure at 1150 °C in dry air, but the least at this temperature in moist air. Examination of dry air formed oxide scales by X-ray diffraction, and scanning electron microscopy with energy-dispersive spectroscopy showed the presence of Mo, and MoO2 with a continuous, protective glassy B2O3–SiO2 top layer. Formation of Zr(MoO4)2 in the Zr-containing alloys had lowered mass loss by arresting MoO3 vaporization, and had enhanced the B2O3–SiO2 scale formation kinetics. Further, Si(OH)4, cristobalite, H3BO3 and MoO3·(H2O)2 appeared to be constituting the oxidation products formed in moist air. Alloying with Zr enhanced the kinetics of protective scale formation by lowering the Moss content, and microstructural refinement. The deterioration of oxidation resistance in moist air was conjectured to be due to longer duration required for protective scale to form, formation of β-cristobalite permitting grain boundary diffusion of oxygen anions, as well as volatile hydrated oxidation products as mentioned above. Formation of ZrSiO4 and dissolved ZrO2 in B2O3–SiO2 scale of the Mo-Si-B-Zr alloys in both dry air and moist air is considered to have contributed to the enhanced protective character of oxide scale by stabilizing the glassy scale. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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8. Placement of phasor measurement unit for complete observability of an isolated microgrid system.
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Ghosh, Suman, Das, J. K., and Chanda, Chandan Kr.
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PHASOR measurement , *MICROGRIDS , *BUSES - Abstract
The role of the microgrid to meet up the localized power demand is of immense importance considering the growing power demand as well as grid inadequacy in Indian power scenario. Apart from meeting localized power demand with various distributed generating sources microgrid can render support to the adjacent main grid or similar localized grid as when needed. This paper presents the techniques for identifying placement sites for Phasor Measurement Units (PMUs) in a microgrid system based on complete observability of the system. The main objective of optimal placement of PMU problem is to determine a minimal set of PMUs such that the whole system is observable. This study has been done on a 14 bus test model with the help of PSAT. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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9. Cr doped ZnO: Investigation of magnetic behaviour through SQUID and ESR studies.
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Amami, P.E., Das, J., Mishra, D.K., Srinivasu, V.V., Sahu, D.R., and Roul, B.K.
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ELECTRON paramagnetic resonance , *RAMAN spectroscopy , *MAGNETIC properties , *SQUIDS , *OPTICAL properties , *MAGNETIC semiconductors , *RAMAN effect , *ZINC oxide - Abstract
Polycrystalline Zn 1-x Cr x O (0.01 ≤ x ≤ 0.09) samples synthesised by solid state reaction technique were sintered at different temperatures following slow step sintering schedule, investigated for optical and magnetic properties using suitable characterisation techniques. Cr 2 O 3 and CrO 2 phases have been detected in the Raman spectra of Zn 1 -x Cr x O samples with x ≥ 0.05. Photoluminescence study indicated improved optical property of the samples compared to undoped ZnO. While low percentage Cr doped samples show diamagnetic behaviour, different types of magnetic orderings are observed in the samples with higher percentage of dopants (x ≥ 0.05) for different sintering temperatures. The spin system and magnetic properties were analysed through Electron Spin Resonance study; g-value of 1.97 indicates Cr in 3+ valence state in ZnO. Presence of both Cr3+ and Cr4+ in ZnO understood to facilitate super exchange interactions to promote room temperature ferromagnetism. ESR study ensures improved magnetic homogeneity through slow step sintering process. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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10. Strain distribution in Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass investigated by in situ tensile tests under synchrotron radiation.
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Stoica, M., Das, J., Bednarcik, J., Franz, H., Mattern, N., Wang, W. H., and Eckert, J.
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METALLIC glasses , *SYNCHROTRON radiation , *ZIRCONIUM , *COPPER , *NICKEL , *ALUMINUM , *DISTRIBUTION (Probability theory) - Abstract
We report on the evolution of the atomic-scale strain tensor of ductile Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass under tensile loading by using x-ray synchrotron radiation. The same kind of samples was previously investigated under compressive loading and revealed yielding at 1690 MPa together with large deformability of up to 160% strain. In tension the samples fracture at a lower stress, 1500 MPa, with no sign of yielding or plastic deformation. With no macroplasticity observed under tension, large differences in the elastic constants obtained from the strain tensor and from ultrasonic sound velocity measurements are revealed. This paper presents in detail the measuring procedure as well as the calculation of the tensile tensor and pair distribution functions of Zr64.13Cu15.75Ni10.12Al10 at different stages of deformation. The results are discussed in comparison with other reported data obtained from x-ray diffraction measurements using synchrotron radiation. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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11. Manifestation of the double-exchange interaction in the Mo¨ssbauer spectrum of mixed-valence systems.
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Coropceanu, V., Bre´das, J. L., Winkler, H., and Trautwein, A. X.
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MOSSBAUER effect , *DIMERS - Abstract
The dependence of the Mössbauer line shape on the double-exchange interaction is studied for dimeric mixed-valence systems in the framework of a model that treats the entire nuclear-electron system quantum-mechanically. The coherent tunneling motion of the "excess" electron between the metal sites produces a resonance splitting of the localized states. In the case of weak double-exchange interaction, this motion shows up as a splitting of Mössbauer lines. This effect however, is readily suppressed by an asymmetry distortion, which destroys the resonance conditions. The origin of different patterns in the temperature dependence of the Mössbauer line shape is discussed. [ABSTRACT FROM AUTHOR]
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- 2002
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12. Nonchiral Bosonization of Strongly Inhomogeneous Luttinger Liquids.
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Das, J. P., Chowdhury, C., and Setlur, G. S.
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LUTTINGER liquids , *GREEN'S functions , *EQUATIONS of motion , *PERTURBATION theory , *RENORMALIZATION group - Abstract
Nonchiral bosonization (NCBT) is a nontrivial modification of the standard Fermi—Bose correspondence in one spatial dimension done to facilitate studying strongly inhomogeneous Luttinger liquids where the properties of free fermions plus the source of inhomogeneities are reproduced exactly. We introduce the NCBT formalism and discuss limit case checks, fermion commutation rules, point-splitting constraints, etc. We expand the Green's functions obtained from NCBT in powers of the fermion—fermion interaction strength (only short-range forward scattering) and compare them with the corresponding terms obtained using standard fermionic perturbation theory. Finally, we substitute the Green's functions obtained from NCBT in the Schwinger—Dyson equation, which is the equation of motion of the Green's functions and serves as a nonperturbative confirmation of the method. We briefly discuss some other analytic approaches such as functional bosonization and numerical techniques like the density-matrix renormalization group, which can be used to obtain the correlation functions in one dimension. [ABSTRACT FROM AUTHOR]
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- 2019
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13. Diffusion and self-gettering of ion-implanted copper in polyimide.
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Das, J. H. and Morris, J. E.
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ION implantation , *COPPER , *BACKSCATTERING - Abstract
Presents information on a study which evaluated the diffusion of ion-implanted copper (Cu) in Kapton films by Rutherford backscattering. Interactions between the metal interconnects and polymide insulators in very large scale integration processes and printed circuit board applications; Ion implantation of Cu into four Kapton types; Diffusion and self-gettering of Cu; Thermal stability of polymide films.
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- 1989
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14. Direct and indirect effects of executive function on reading comprehension in young adults.
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Georgiou, George K. and Das, J. P.
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EXECUTIVE function , *READING comprehension , *FLUENCY (Language learning) , *VOCABULARY , *ACADEMIC achievement , *YOUNG adults , *ADULT education - Abstract
The purpose of this study was to examine what components of executive function (EF) – inhibition, shifting and updating/working memory – predict reading comprehension in young adults. Ninety university students (65 females, 25 males; mean age = 21.82 years) were assessed on shifting (Planned Connections and Colour/Shape Shifting), inhibition (Colour‐Word Stroop and Number Stroop), updating/working memory (Digit Memory and Listening Span), reading fluency (Word Reading Efficiency), vocabulary (Peabody Picture Vocabulary Test), and reading comprehension (Nelson‐Denny Reading Test). The results of path analysis indicated that only shifting predicted directly reading comprehension. These findings extend those of previous studies showing that different EF components predict different reading outcomes and suggest that EF has a place in reading comprehension models over and above traditional predictors of reading comprehension such as reading fluency and vocabulary. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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15. Operation and Starting of PAM Motors Using Vacuum Contactors.
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Das, J. C. and Lancaster, Kevin
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AMPLITUDE modulation , *ELECTRIC motors , *ELECTRIC contactors , *MICROPROCESSORS , *VARIABLE speed drives - Abstract
Pole amplitude modulation (PAM) motor is a single-winding two speed motor used for induced draft fans. Its cost is much less than that of an adjustable speed drive motor. This paper is prompted by a rigorous study that was undertaken to replace an existing oil filled, leaky, transfer-switch type, two-speed motor starter, with an adjunct of tens of hard wired timers in a utility installation. The paper describes the fundamental operation of a PAM motor, different torque speed and thermal withstand characteristics at two speeds, and design of an alternate starter using conventional vacuum contactors with modern multifunction microprocessor relays to provide effective protection during normal two-speed operation and starting. [ABSTRACT FROM AUTHOR]
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- 2018
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16. Isolation, culture, characterization, and osteogenic differentiation of canine endometrial mesenchymal stem cell.
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Sahoo, A. K., Das, J. K., and Nayak, S.
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CELL differentiation , *BONE growth , *ENDOMETRIUM , *MESENCHYMAL stem cells , *GENE expression - Abstract
Aim: In this study, the canine endometrium tissue is characterized for its stem cell properties such as adherence to tissue culture plate (plasticity), short population doubling time, serial clonal passaging, long-term culturing properties, stem cell marker expression, and multilineage differentiation potential. Materials and Methods: The present work describes a novel isolation protocol for obtaining mesenchymal stem cells from the uterine endometrium and is compared with cells derived from umbilical cord matrix as a positive control. These cells are clonogenic, can undergo several population doublings in vitro, and can be differentiated to the osteocytes in mature mesenchymal tissues when grown in osteogenic differentiation media as detected by Alizarin Red-S staining. Results: It is reported for the first time that the cells derived from the canine endometrium (e-multipotent stem cells [MSCs]) were able to differentiate into a heterologous cell type: Osteocytes, thus demonstrating the presence of MSCs. Thus, the endometrium may be told as a potential source of MSCs which can be used for various therapeutic purposes. Conclusion: The endometrium can be used as a potential source of MSCs, which can be used for various therapeutic purposes. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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17. Statistical model for prebreakdown current jumps and breakdown caused by single traps in magnetic tunnel junctions.
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Das, J., Degraeve, R., Groeseneken, G., Stein, S., Kohlstedt, H., Borghs, G., and De Boeck, J.
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DETECTORS , *ALUMINUM , *ULTRAVIOLET radiation , *MAGNETISM - Abstract
To obtain reliable magnetic tunnel junctions (MTJs) for sensor and memory applications, the quality of the Al[SUB2]O[SUB3] tunnel barrier is extremely important. Here, we studied the reliability of MTJs with a 1.6 nm Al[SUB2]O[SUB3] tunnel barrier formed by ultraviolet light assisted oxidation. In the stress measurements, prebreakdown current jumps and, finally, breakdown are observed. We show, by using statistics, that both the current jumps and the final breakdown can be attributed to single trap generation. Moreover, we can relate the current jump height to the trap location. In this way, we reveal the breakdown mechanism in MTJs and illustrate the importance of reliability studies. [ABSTRACT FROM AUTHOR]
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- 2003
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18. Area scaling and voltage dependence of time-to-breakdown in magnetic tunnel junctions.
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Das, J., Degraeve, R., Roussel, P., Groeseneken, G., Borghs, G., and Boeck, J. De
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RANDOM access memory , *MAGNETIC fields , *QUANTUM tunneling - Abstract
The development of magnetic random access memory requires very reliable magnetic tunnel junctions (MTJs). However these devices are prone to dielectric breakdown. To investigate the reliability of the MTJs, we performed constant voltage stress tests. This study shows the area scaling and the voltage dependence of the time-to-breakdown t[sub BD] of exchange biased, naturally oxidized MTJs. The fraction of broken devices F is plotted on a Weibull scale. The Weibull fit of our data shows clearly that t[sub BD] scales with the area, meaning that the breakdown sites are randomly distributed. Moreover, the Weibull distributions have a constant slope β (=0.35) and show no tails. This suggests that only one breakdown mode is observed. It is not clear yet whether an intrinsic or extrinsic failure mechanism is causing the breakdown, but considering the small Weibull slope, extrinsic breakdown caused by randomly distributed process-induced defects in the oxide is most plausible. Second, the voltage dependence of t[sub BD] is studied. To fit the data, a linear dependence of 1og(t[sub BD]) on stress voltage is assumed. It is however not yet proven whether this model is applicable for ultrathin Al[sub 2]O[sub 3] barriers. [ABSTRACT FROM AUTHOR]
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- 2002
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19. Degradation and time dependent breakdown of stressed ferromagnetic tunnel junctions.
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Das, J., Degraeve, R., Boeve, H., Duchamps, P., Lagae, L., Groeseneken, G., Borghs, G., and De Boeck, J.
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FERROMAGNETISM , *QUANTUM tunneling - Abstract
Ferromagnetic tunnel junctions are very sensitive to degradation and breakdown, due to the ultrathin (∼1 nm) tunnel barrier. When the junction is stressed with a constant current or voltage, a conductance change of the tunnel junction is observed. Sufficiently high stress will lead to breakdown of the junction. As in SiO[sub 2] gate oxide reliability studies, the Weibull distribution plot can be obtained from the time to breakdown data. The dependence of the Weibull function on the area and the stress conditions is studied for the Al[sub 2]O[sub 3] barrier of the tunnel junctions. This is the first step of a systematic study of reliability, which is an important issue for the use of tunnel junctions in, e.g., magnetic random access memory applications. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]
- Published
- 2001
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20. Integtration of spin valves and GaAs diodes in magnetoresistive random access memory cells.
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Boeve, H. and Das, J.
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RANDOM access memory , *SPIN waves - Abstract
Demonstrates a magnetoresistive random access memory based on a dynamic random access memory-like floor plan. Fabrication process; Magnetoresistance in a single cell; Memory function; Conclusion.
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- 1999
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21. Heating of carriers as controlled by the combined interactions with acoustic and piezoelectric phonons in degenerate III-V semiconductors at low lattice temperature.
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Bhattacharya, D.P., Das, J., Basu, A., and Das, B.
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SEMICONDUCTORS , *PHONONS , *SYMMETRY (Physics) , *CRYSTAL lattices , *LOW temperatures , *SCATTERING (Physics) - Abstract
In compound semiconductors which lack inversion symmetry, the combined interaction of the electrons with both acoustic and piezoelectric phonons is dominant at low lattice temperatures (~ 20 K). The field dependence of the effective electron temperature under these conditions, has been calculated by solving the modified energy balance equation that takes due account of the degeneracy. The traditionally used heated Fermi-Dirac (F.D.) function for the non-equilibrium distribution function is approximated by some well tested model distribution. This makes it possible to carry out the integrations quite easily and, thus to obtain some more realistic results in a closed form, without taking recourse to any oversimplified approximations. The numerical results that follow for InSb, InAs and GaN, from the present analysis, are then compared with the available theoretical and experimental data. The degeneracy and the piezoelectric interaction, both are seen to bring about significant changes in the electron temperature characteristics. The scope for further refinement is discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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22. Socio-economic Correlates, Technological Gap and Training Nneeds of the Farmers for Increasing Pineapple Productivity in Meghalaya.
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Das, J. K., Sangma, Lima N., and Majumder, D.
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PINEAPPLE growing , *AGRICULTURAL productivity , *CROPPING systems , *SOCIOECONOMICS - Abstract
The study was conducted during 2012-13 to identify the role of different socio-economic variables on yield, income, technological gap and training need confronting the productivity of pineapple in the state of Meghalaya. Study revealed that the variable economic motivation (0.130) have recorded a positive and significant correlation with the variable income, of the respondents. The correlation coefficient between yield (Y2) and all independent variables revealed that education of farmers (0.125), Market orientation (0.095) and cultivation efficiency (0.130) have recorded significant and positive correlation with the yield of the respondents. It is also recorded that variables Family type (-0.105), Management orientation (-0.167) and utilization of mass media (-0.137) are significant but negatively correlated with the yield of pineapple. In the path analysis, it has been found that the variable utilization of mass media has routed highest indirect effect on income as many as 16 exogenous variables. Similarly, it has also identified that both the variables management orientation and education of farmers have routed highest indirect effect on yield as many as 8 exogenous variables. The result of technological gap revealed that the highest gap (60.75%) and the lowest gap (30.50%) was found in the knowledge of 'sucker' and in 'post harvest technology' respectively among the pineapple growers. The farmers have shown maximum interest (rank-I) for training on 'improved cultural practices' (59.66%) and minimum interest (rank-X) on 'cropping system' (45.86%) in pineapple cultivation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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23. Spin canting and magnetism in nano-crystalline Zn1−xAlxO.
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Das, J., Mishra, D.K., and Srinivasu, V.V.
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ZINC compounds , *MAGNETISM , *NANOCRYSTALS , *DOPED semiconductors , *ALUMINUM - Abstract
Al doped nanocrystalline ZnO (∼30 nm) with composition Zn 1−x Al x O (0.005 < x < 0. 03) were synthesised by pyrophoric technique and sintered at 650 °C. We performed detailed electron spin resonance (ESR) studies on this system to understand the spin ordering and magnetism. The spin canting order and magneto-crystalline anisotropy obtained through ESR measurements follow each other and have a broad peak for Al doping concentration of 0.02, which also matches with the saturation magnetisation ‘M s ’ maximum, that is obtained by direct magnetisation measurement using VSM. However, it is intriguing that the spin susceptibility has a broad minimum around the same doping level (0.02). Through the ESR measurement this observed weak ferromagnetism is attributed to the spin canted magnetism in the system. Other supportive experimental data from UV–Vis, PL and Raman analysis give a clear picture of defect structures in the form of oxygen vacancies that faciliates the occurrence of room temperature ferromagnetism which of course is through spin canting mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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24. High temperature oxidation response of Al/Ce doped Mo–Si–B composites.
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Das, J., Roy, B., Kumar, N.K., and Mitra, R.
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OXIDATION , *HIGH temperatures , *THERMISTORS , *CHEMICAL reactions , *ISOTHERMAL processes - Abstract
A systematic investigation has been performed to study the oxidation response of Mo 76 Si 14 B 10 alloy doped with traceable amount of Ce and Al at temperature in the range of 900–1300 °C. The resistance to degradation of Mo 76 Si 14 B 10 ≥ 900 °C has increased due to the dissociation of Mo-oxides into Mo in protective glassy borosilicate layer. Addition of Ce aggrieves oxidation initially, but protection is achieved upon exposure within 3 h at all the different temperatures. No passivation has occurred in Al containing alloy due to the dissolution of Al 2 O 3 in the borosilicate scale leading to the precipitation of aluminum-borate and mullite along with unreacted cristoballite. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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25. Structural controls on topography and river morphodynamics in Upper Assam Valley, India.
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Borgohain, S., Das, J., Saraf, A.K., Singh, G., and Baral, S.S.
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TOPOGRAPHY , *STRUCTURAL geology , *TOPOGRAPHIC maps , *WATERSHEDS , *GEOMORPHOLOGY , *RELIEF models , *GEOLOGICAL basins - Abstract
The basement in Upper Assam foreland basin exhibits a typical flexure pattern. An elongated continuous subsurface basement high has developed between Himalaya and Naga-Patkai ranges. A few prominent basement lows have developed adjacent to the foothill regions. It is noticed that the general topographic slope near the foothill regions is not only controlled by aggradation process, but also influenced by the flexured basement of the region. The basement lows have influenced the overlying topography significantly. Rivers flowing over those regions have shown unidirectional lateral migration. North bank tributaries like Subansiri, Jiadhal and Dikrang have been affected by the Subansiri basement low. Coseismic subsidence of sediments over Subansiri basement low had resulted subsidence of the North Lakhimpur-Ranga Nadi region in 1950 Assam earthquake. Some south bank tributaries like Disang and Dikhow have been affected by Nazira basement low. Topographic elevation along the Subansiri river is lower than that part of the Brahmaputra located south of Majuli. This typical topographic setting of the region makes the mouth of the Subansiri river and Majuli region highly susceptible to erosion. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
26. Application of STATCOM to an Industrial Distribution System Connected to a Weak Utility System.
- Author
-
Das, J. C
- Subjects
- *
ELECTRIC potential , *ELECTRIC power supplies to apparatus , *ELECTRIC machinery , *ELECTRIC power , *ELECTRIC currents - Abstract
The application of STATCOM or STATCON is common in transmission systems—the device has a capability of P-Q control in four quadrants. DSTATCOM (for distribution systems) and dynamic voltage regulator are somewhat synonymous. This paper describes a unique distribution system with three in-plant generators and an interconnection to a weak utility system at 44 kV; the three-phase short-circuit level at the utility source is only 151.7 MVA. So long as the generators are in operation, the power factor at the utility interconnection can be maintained close to unity and the voltage profiles in the system are acceptable—a total of 64 MW of load is served from 3–13.8-kV interconnected bus system. To control the voltage dips on loss of generation, 31 Mvar of capacitor filters (as the distribution system has considerable drive system loads and harmonic analysis study is conducted) are installed, yet the voltage dip can exceed 25%. A STATCOM can restore the voltage in one-half cycle. The STATCOM is also briefly compared with other technologies like TCR and TSC. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
27. Laparoscopic Management of Tubal Ectopic of Heterotopic Pregnancy.
- Author
-
SAHA, E., DAS, J., MONIRUZZAMAN, M., and BACHER, C. R.
- Subjects
- *
ECTOPIC pregnancy , *ABORTION - Abstract
A heterotopic pregnancy is a rare complication of pregnancy in which both extra-uterine (ectopic pregnancy) and intrauterine pregnancy occur simultaneously. The prevalence of heterotopic pregnancy is estimated at 0.6-2.5: 10,000 pregnancy. It is a challenge for obstetrician to manage the tubal pregnancy without interruption of intrauterine pregnancy. Here we describe a case who had left tubal alive ectopic pregnancy & also intrauterine alive pregnancy simultaneously after a natural conception. This patient was managed successfully with laparoscopic left salpingectomy, and intrauterine pregnancy has been continuing. There are some precautions during laparoscopic procedure & post operative period which can help for continuation of intrauterine pregnancy. In our clinical experience, this is an extreme rare disorder and we feel interest to report this case. A heterotopic pregnancy can result from a natural conception; it requires a high index of suspicious for early and timely diagnosis; a timely intervention can result in a successful outcome of the intrauterine fetus. [ABSTRACT FROM AUTHOR]
- Published
- 2016
28. Morphodynamic changes of Lohit River, NE India: GIS-based study.
- Author
-
Borgohain, S., Das, J., Saraf, A. K., Singh, G., and Baral, S. S.
- Subjects
- *
WATERSHEDS , *RIVERS , *RIVER channels , *TOPOGRAPHY - Abstract
The Lohit River is a south bank tributary of the Brahmaputra River. Till 1987, the Lohit River used to meet the Brahmaputra at a place near Bairagi Chapari (27.77°N, 95.44°E). By 1995, the confluence point had shifted about 20 km downstream. One small channel of the Lohit River captured the Dangori River during the 1988 flood. Gradually the Lohit River started flowing along the captured channel. By 1995, it became the trunk channel of the Lohit River and Dibru Saikhowa region became an island. Banklines of Brahmaputra and Lohit rivers have undergone significant changes near their confluence point within the last few decades. By 1987, the south bank of the Brahmaputra near Rohmoria (27.55°N, 95.15°E) shifted about 1.6 km southward from its position in 1973. Interestingly, within the period 1988-90 the south bank shifted about 4.1 km south. This major shifting was the result of capturing of the Dangori River by the Lohit River. However, migration of the rivers towards the south has stopped after 1995. Analysis of SRTM DEM reveals that topographic elevation has played a major role in changing the course of the Lohit River. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
29. Pseudotumor Cerebri : A Rare Presentation of Systemic Lupus Erythematosus.
- Author
-
DAS, A., DAS, J. C., AHMAD, A. A., and KAHHAR, M. A.
- Subjects
- *
INTRACRANIAL hypertension , *SYSTEMIC lupus erythematosus , *ADRENOCORTICAL hormones , *HORMONE therapy - Abstract
Raised intracranial pressure in the absence of an intracranial mass or hydrocephalus (BIH or pseudotumor cerebri) has been described in association with many conditions including SLE. Several pathogenic pathways tie BIH with SLE as thrombotic obliteration of cerebral arteriolar and venous systems and immune complex deposition within the arachnoid villi that are responsible for cerebrospinal fluid (CSF) absorption. The diagnosis of BIH was confirmed by increased intracranial pressure in the absence of any abnormal radiological findings of the brain. We report a young woman with SLE complicated by BIH which resolved with corticosteroid therapy and osmotic diuretics. [ABSTRACT FROM AUTHOR]
- Published
- 2016
30. Out-of-Step and Single Phasing Protection of Synchronous Chipper Motors.
- Author
-
Das, J. C., Steinmetz, Jon D., and McPhee, Aaron A.
- Subjects
- *
SYNCHRONOUS electric motors , *INSTALLATION of equipment , *PAPER mills , *STABILITY (Mechanics) , *IMPACT loads - Abstract
Chipper motors in pulp and paper mill environment are of special design—the stability on impact loads is one important consideration. The power factor under normal operation will continuously swing due to varying loads. This paper describes the guesswork-free rigorous calculations of pull-out (out-of-step) power factor based on the parameter of an actual installation. Single phasing is rather a rare occurrence; however, such an event has been experienced in an installation due to overheating and arcing at the fuse clips in a NEMA E2 starter of a chipper motor. Discussions on the single-phase protection of synchronous motors and recommended settings are provided. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
31. Selective High-Resistance Grounding System for a Cogeneration Facility.
- Author
-
Das, J. C.
- Subjects
- *
ELECTRIC current grounding , *COGENERATION of electric power & heat , *ELECTRIC power plants , *ELECTRIC utilities , *ELECTRIC power distribution grids - Abstract
This paper describes a selective high-resistance grounding (HRG) system for a large industrial facility with two in-plant generators in cogeneration mode and two utility transformers. In a five-step coordination using sensitive ground fault nondirectional and directional relays, ground faults throughout the distribution system are cleared with a maximum pickup setting of 6 A, and time delay of 0.25 s. A major consideration for HRG systems is that the stray capacitance charging current of the system should be small (10–15 A) to prevent ground fault damage. If the fault is left in place for some duration for a single-line-to-ground fault, insulation stresses occur due to higher line-to-ground voltages on two unfaulted phases. This paper demonstrates that with selective HRG, both these concerns are mitigated. A selective HRG is a bridge between the classical concepts of HRG and low-resistance grounding. The modern advancements in ground sensors and protective relaying can selectively clear low levels of ground fault currents, which make selective HRG a reality. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
32. Atmospheric Ar and Ne returned from mantle depths to the Earth's surface by forearc recycling.
- Author
-
Baldwin, Suzanne L. and Das, J. P.
- Subjects
- *
SURFACE of the earth , *MINERALS , *SUBDUCTION , *CRYSTALLIZATION , *PRESSURE - Abstract
In subduction zones, sediments, hydrothermally altered lithosphere, fluids, and atmospheric gases are transported into the mantle, where ultrahigh-pressure (UHP) metamorphism takes place. However, the extent to which atmospheric noble gases are trapped in minerals crystallized during UHP metamorphism is unknown. We measured Ar and Ne trapped in phengite and omphacite from the youngest known UHP terrane on Earth to determine the composition of Ar and Ne returned from mantle depths to the surface by forearc recycling. An 40Ar/39Ar age [7.93 ± 0.10 My (1σ)] for phengite is interpreted as the timing of crystallization at mantle depths and indicates that 40Ar/39Ar phengite ages reliably record the timing of UHP metamorphism. Both phengite and omphacite yielded atmospheric 38Ar/36Ar and 20Ne/22Ne. Our study provides the first documentation, to our knowledge, of entrapment of atmospheric Ar and Ne in phengite and omphacite. Results indicate that a subduction barrier for atmospheric-derived noble gases does not exist at mantle depths associated with UHP metamorphism. We show that the crystallization age together with the isotopic composition of nonradiogenic noble gases trapped in minerals formed during subsolidus crystallization at mantle depths can be used to unambiguously assess forearc recycling of atmospheric noble gases. The flux of atmospheric noble gas entering the deep Earth through subduction and returning to the surface cannot be fully realized until the abundances of atmospheric noble gases trapped in exhumed UHP rocks are known. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
33. SMA – OUTCOME MEASURES AND REGISTRIES: EP.263 TREAT-NMD core dataset for SMA - an important tool for post marketing surveillance.
- Author
-
Das, J., Hodgkinson, V., Rodrigues, M., Bullivant, J., Walker, H., Straub, V., Campbell, C., Guglieri, M., and Ambrosini, A.
- Subjects
- *
MEASUREMENT - Published
- 2021
- Full Text
- View/download PDF
34. Low Field Microwave Absorption in Mn:Ni Co-Doped ZnO μm Size Powders.
- Author
-
MAHULE, T. S., DAS, J., SAHU, D. R., and SRINIVASU, V. V.
- Subjects
- *
ZINC oxide , *ABSORPTION , *POLYCRYSTALS , *MAGNETIC fields , *TRANSITION metals - Abstract
Polycrystalline Zn1-x(Mn:Ni)x0 sample for x = 0.02 were synthesized by solid state route. We have observed low field microwave absorption in these powder samples. Low field microwave absorption signal is out of phase with the regular resonance signal indicating the microwave absorption has a minimum at zero field and the absorption of microwaves increases with increase of magnetic field. Low field microwave absorption in these powders is qualitatively different from their bulk pellets. Temperature dependence of the low field microwave absorption indicates a line shape evolution and a non-monotonic peak to peak intensity change. Further, we have observed the absence of 2nd harmonic in this low field microwave absorption, indicating low field microwave absorption in these transition metal co-doped ZnO powders is not non-linear in nature. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
35. Inaugural Function of the Geological Society of India Regional Centre — Odisha.
- Author
-
Khaoash, Somnath and Das, J. N.
- Subjects
- *
EARTH system science - Published
- 2022
- Full Text
- View/download PDF
36. PO-1547 Dosimetric study of Adaptive radiotherapy (ART) for locally advanced head and neck cancer.
- Author
-
Das, J., Goswami, B., Goswami, S., Deka, K.J., Bora, G., and Das, L.
- Subjects
- *
HEAD & neck cancer , *RADIATION dosimetry , *RADIOTHERAPY - Published
- 2021
- Full Text
- View/download PDF
37. University Students With Poor Reading Comprehension.
- Author
-
Georgiou, George K. and Das, J. P.
- Subjects
- *
ANALYSIS of covariance , *ANALYSIS of variance , *COLLEGE students , *STATISTICAL correlation , *MULTIVARIATE analysis , *READING disability , *RESEARCH funding , *STATISTICAL sampling , *TASK performance , *CONTROL groups , *DATA analysis software , *DESCRIPTIVE statistics - Abstract
The present study aimed to examine the nature of the working memory and general cognitive ability deficits experienced by university students with a specific reading comprehension deficit. A total of 32 university students with poor reading comprehension but average word-reading skills and 60 age-matched controls with no comprehension difficulties participated in the study. The participants were assessed on three verbal working memory tasks that varied in terms of their processing demands and on the Das–Naglieri Cognitive Assessment System, which was used to operationalize intelligence. The results indicated first that the differences between poor and skilled comprehenders on working memory were amplified as the processing demands of the tasks increased. In addition, although poor comprehenders as a group had average intelligence, they experienced significant difficulties in simultaneous and successive processing. Considering that working memory and general cognitive ability are highly correlated processes, these findings suggest that the observed differences between poor and skilled comprehenders are likely a result of a deficient information processing system. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
38. High strength Ni–Zr–(Al) nanoeutectic composites with large plasticity.
- Author
-
Maity, T. and Das, J.
- Subjects
- *
NICKEL compounds , *METALLIC composites , *MICROMETERS , *REINFORCED plastics , *SURFACE hardening , *ADDITION reactions - Abstract
Micrometer-sized γ−Ni dendrite reinforced nanoeutectic matrix composites have been developed in (Ni 0.92 Zr 0.08 ) 100– x Al x (0 ≤ x ≤ 4) by arc melting. The eutectic matrix is composed of alternate nano-lamellae of intermetallic Ni 5 Zr and fcc–Ni solid solution phases. All these composites exhibit very high strength, large compressive plasticity ∼25% and strain-hardening up to 1780 MPa. Al dissolves in γ−Ni(Zr) solid solution phase, decreases its hardness/strength, and increases the volume % of γ−Ni dendrite from 20% ( x = 0) to 29% ( x = 4). Whereas, refinement of the eutectic lamellae thickness from 275 nm ( x = 0) to 160 nm ( x = 4) increases the matrix hardness and retains the global strength of the composites. The effect of Al addition on the microstructure formation, volume fraction as well as the length scale of the constituent phases, and mechanical properties, have been discussed using an analytical model. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
39. Synthesis of mullite-based coatings from alumina and zircon powder mixtures by plasma spraying and laser remelting.
- Author
-
Hazra, S., Das, J., and Bandyopadhyay, P.P.
- Subjects
- *
MULLITE synthesis , *SURFACE coatings , *ALUMINUM oxide , *ZIRCON , *POWDER metallurgy , *PLASMA spraying , *LASER beams - Abstract
A mechanical mixture of alumina and pulverized zircon sand in 3:2 M ratio has been plasma sprayed to obtain mullite coating. Thereafter, the top layer of the coating has been remelted using laser. The presence of a mullite phase in the as-sprayed and laser remelted coatings has been confirmed qualitatively using X-ray diffraction. Both as-sprayed and laser remelted coatings have been characterized for their microstructure, hardness and porosity. The ultrafine grain structure of the coating produced by rapid quenching has been analyzed using transmission electron microscope. Presence of a mullite phase in the coatings has also been confirmed using small angle electron diffraction. Laser remelting has resulted in an appreciable reduction in porosity and increase in hardness in the coatings. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
40. Design and Application of a Second-Order High-Pass Damped Filter for 8000-hp ID Fan Drives—A Case Study.
- Author
-
Das, J. C.
- Subjects
- *
LOAD flow analysis (Electric power systems) , *HARMONIC distortion (Physics) , *ELECTRIC distortion , *ELECTRIC filter design & construction , *ELECTRIC potential - Abstract
The design and application of second-order high-pass filters are described for 2-8000-hp ID fan drives, which reduces the voltage harmonic distortion at point of common coupling (PCC) from a high value of 42.41% to 1.32% and also brings the current distortion at PCC within IEEE 519 limits. Failure of the electronic components of the 8000-hp ID fan drives and shutdown of electronic loads downstream of the main 13.8-kV buses were observed, which led to investigation of harmonic problems and their mitigation. The second-order high-pass filters are applied for the first time in industry for such a harmonic distortion problem. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
41. Possible Upgrade of an Existing Tandem Accelerator Facility to an ISOL Facility for Neutron-Rich Rare Isotope Beams.
- Author
-
Das, J. J., Kanjilal, D., and Roy, A.
- Subjects
- *
NEUTRONS , *LASER beams , *ION sources , *ELECTRON accelerators , *HELIUM - Abstract
The feasibility and utility of a Helium multi-jet system to transport fission fragments vertically up to an ion source 50 m above ground level is explored. This idea opens up the possibility of using the existing 15-UD tandem and SC linac accelerator system at Inter University Accelerator Center (IUAC) as a post accelerator for rare isotope beams (RIBs). This could considerably speed up the upgrade of the facility to a RIB facility since the driver accelerator (e.g. a 50 MeV electron accelerator) can be purchased. We find that such a facility will be competitive for refractory neutron-rich isotopes and can later be combined with a positive ion injector to produce a large number of beam species with higher intensities. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
42. Studies of ionization of hydrogen atoms by electron impact in hyperspherical partial wave theory from below 1eV excess energies to intermediate energies.
- Author
-
Das, J. N., Paul, S., and Chakrabarti, K.
- Subjects
- *
IONIZATION of gases , *HYDROGEN , *ELECTRON impact ionization , *ELECTRONIC excitation , *GASES - Abstract
Hyperspherical partial wave theory has been applied in the study of ionization of hydrogen atoms by electron impact from very low energies (1.0eV, 0.5eV and 0.3eV above threshold) to intermediate energies (60eV). The various ionization cross sections which have been calculated are generally in good agreement with the experiments. Some times the agreements are even better than those of other high level theories, like ECS and CCC theories, requiring elaborate computations. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
43. Pancreatic-Biliary Ascariasis in an Infant.
- Author
-
Roy, K., Das, J., Mukherjee, D., and Kundu, R.
- Subjects
- *
ASCARIASIS in children , *HYPERBILIRUBINEMIA - Abstract
Ascaris infestation that too causing biliary obstruction is very rare in infancy even in endemic area. Adult Ascaris diameter (3-6 mm) is more than the average diameter of CBD in paediatric population, which is 1.27 +/- 0.67 mm. We are reporting a baby of seven months who presented with conjugated hypebilirubinemia and pancreatitis due to Round Worm in CBD. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
44. Arc-Flash Hazard Calculations in LV and MV DC Systems—Part I: Short-Circuit Calculations.
- Author
-
Das, J. C.
- Subjects
- *
ELECTRIC arc , *SHORT-circuit currents , *DIRECT currents , *ELECTRIC motors - Abstract
The IEEE 1584 Guide does not address arc-flash hazard in dc systems. The interest in this subject is evidenced by current publications. The National Fire Protection Association (NFPA) 2012 methodology has added a small description of the calculations of arc-flash hazard in dc systems. However, there are serious inaccuracies in the application of the methodology that is advocated in the NFPA. A review of the current literature indicates that there is no comprehensive document on the subject and that some of the assumptions made in the current literature are not accurate, e.g., with respect to the short-circuit current profiles and protective devices in dc systems, which are very fundamental to the accurate calculations of arc-flash hazard in dc systems. This paper is presented in two parts. This part provides equations with practical examples of short-circuit calculations in dc systems. The second part provides the analysis of arc-flash hazard. Accurate calculations of the short-circuit currents and ascertaining their profiles is the first step in the arc-flash hazard analysis. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
45. Arc-Flash Hazard Calculations in LV and MV DC Systems Part—II: Analysis.
- Author
-
Das, J. C.
- Subjects
- *
DIRECT currents , *SHORT-circuit currents , *LOW voltage systems , *SEMICONDUCTOR devices - Abstract
Based on the results of the short-circuit calculations in Part I of this paper, the calculation of the arc-flash hazard in dc systems is demonstrated. Much like ac systems, the arcing currents are not the same as the short-circuit currents. The National Fire Protection Association 2012 methodology recommends that the arcing current be taken as 50 $\%$ of the calculated dc short-circuit current and that the arc-flash hazard be calculated for a time duration of 2 s. Both these concepts are much flawed and will give inaccurate results. It is also imperative to appreciate the short-circuit protection in dc systems. Semiconductor devices have very little energy let-through withstand capability and are protected with fast-acting semiconductor fuses or dc circuit breakers that may arrest the prospective short-circuit current and limit the incident energy release to a small value. This paper calculates the arc-flash hazard in specimen cases to demonstrate the methodology of the calculations in low-voltage and medium-voltage dc systems. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
46. Empowering Farm Women Through Income and Livelihood Generation.
- Author
-
Das, J. K.
- Subjects
- *
WOMEN in agriculture , *FARM life , *SOCIAL conditions of women , *ON-farm agricultural research , *DECISION making , *SELF-efficacy - Abstract
Women empowerment covers many influencing factors wherein decision making power as an important indicator generally comes from the economic contribution; economic contribution of women through the access of livelihood generation puts forward the importance of women in the family and society at large. The present study is an endeavor to identify the different independent variables of on-farm and off-farm activities from where their power of empowerment emerges. The study was conducted in area under Haringhata Panchayat Samity, West Bengal with a total sample size of 100 in 5 selected Mouzas randomly. The statistical tools applied were correlation, multiple regression, path analysis, chi-square test, paired t-test and canonical correlation. It is observed that the variables like age, material possession, mass media exposure, family income and socio-economic status have got the important bearing on the gain in empowerment of women. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
47. Microstructure and size effect in ultrafine (Ti0.705Fe0.295)100 − x Sn x (0⩽ x ⩽4at.%) composites.
- Author
-
Maity, T. and Das, J.
- Subjects
- *
TITANIUM compounds , *METAL microstructure , *METALLIC composites , *STRAINS & stresses (Mechanics) , *DISLOCATION density , *MECHANICAL properties of metals - Abstract
Highlights: [•] Effect of Sn on the indentation size effect in Ti–Fe–(Sn) has been explored. [•] Fitting through ISE models point the existence of strain gradient beneath indenter. [•] Correlation has been established between dislocation density, grain size and ISE. [•] ISE in Ti–Fe–Sn ultrafine composites requires a dislocation density of ∼1014–1016/m2. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
48. Antibacterial effects of biosynthesized silver nanoparticles using aqueous leaf extract of Rosmarinus officinalis L.
- Author
-
Das, J. and Velusamy, P.
- Subjects
- *
SILVER nanoparticles , *BIOSYNTHESIS , *ROSEMARY , *PLANT extracts , *FLAVONOIDS , *BACTERICIDES - Abstract
Highlights: [•] This is first study on biologically synthesized AgNPs from aqueous leaf extract R. officinalis. [•] Spherical shaped AgNPs were obtained within 14.20–42.42nm. [•] Biomolecules such as flavonoids, terpenoids and thiamine were found to be active molecules for AgNPs synthesis. [•] Synthesized AgNPs showed effective bactericidal activity. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
49. POSA299 Impact of Implementing Difference Method for Sampling Ordered Parameter in Probabilistic Sensitivity Analysis (PSA) on Cost Effectiveness (CE) Model Outcome.
- Author
-
Das, J, Mishra, A, and Partha, G
- Subjects
- *
COST effectiveness , *SENSITIVITY analysis , *SAMPLING methods - Published
- 2022
- Full Text
- View/download PDF
50. Enhanced magnetocaloric effect in Fe-rich (NixFe1-x)70.5B17.7Si7.8Ti4 (x = 0.3 and 0.4) mechanically alloyed nanocrystalline powder.
- Author
-
Anand, K.S. and Das, J.
- Subjects
- *
MECHANICAL alloying , *MAGNETOCALORIC effects , *ALLOY powders , *DIFFERENTIAL scanning calorimetry , *HEAT treatment , *CALORIMETRY - Abstract
• (Ni x Fe 1- x) 70.5 B 17.7 Si 7.8 Ti 4 (at.%) have been prepared by ball milling. • Milled powders consist of α and γ phase in x = 0.3 and 0.4, respectively. • The onset temperature of crystallization increases as Fe content decreases. • The heat-treated x = 0.4 powder shows a |−Δ S M | of 0.695 J/kgK at 19.9 kOe. We report the evolution of nanocrystalline α -Fe and γ-Ni phases in (Ni x Fe 1- x) 70.5 B 17.7 Si 7.8 Ti 4 (at.%) where, x = 0.3 and 0.4, upon mechanical alloying of elemental powder mixtures up to 36 h. The effect of milling time on the nanostructure evolution, thermal stability, and magnetic properties have been investigated throughly using x-ray diffraction (XRD), differential scanning calorimetry (DSC), and vibrating sample magnetometry (VSM). XRD analysis of the as-milled powders revealed that the lattice parameter and the crystallite size of α -Fe phase lies in between 0.2850-0.2972 nm and 3–14 nm; whereas the same for γ-Ni lies in between 0.3550-0.3608 nm and 8–41 nm, respectively, during milling. The thermal analysis of the as-milled powders suggests that the onset temperature of crystallization increases as Fe content decreases. The thermomagnetic measurement of the heat treated powders has revealed the T C of α -Fe phase in x = 0.3 to be 590 K and that of γ-Ni phase in x = 0.4 to be 375 K. The maximum magnetic entropy change has been estimated to be 0.159 Jkg-1K−1 in x = 0.3, while that of x = 0.4 has been found to be 0.695 Jkg-1K−1 at an applied magnetic field of 19.9 kOe. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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