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Jain, Vikas,Nayak, A.K.,Dhiman, M.,Kulkarni, P.P.,Vijayan, P.K.,Vaze, K.K. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.5
Pressing demands of economic competitiveness, the need for large-scale deployment, minimizing the need of human intervention, and experience from the past events and incidents at operating reactors have guided the evolution and innovations in reactor technologies. Indian innovative reactor 'AHWR' is a pressure-tube type natural circulation based boiling water reactor that is designed to meet such requirements, which essentially reflect the needs of next generation reactors. The reactor employs various passive features to prevent and mitigate accidental conditions, like a slightly negative void reactivity coefficient, passive poison injection to scram the reactor in event of failure of the wired shutdown systems, a large elevated pool of water as a heat sink inside the containment, passive decay heat removal based on natural circulation and passive valves, passive ECC injection, etc. It is designed to meet the fundamental safety requirements of safe shutdown, safe decay heat removal and confinement of activity with no impact in public domain, and hence, no need for emergency planning under all conceivable scenarios. This paper examines the role of the various passive safety systems in prevention and mitigation of severe plant conditions that may arise in event of multiple failures. For the purpose of demonstration of the effectiveness of its passive features, postulated scenarios on the lines of three major severe accidents in the history of nuclear power reactors are considered, namely; the Three Mile Island (TMI), Chernobyl and Fukushima accidents. Severe plant conditions along the lines of these scenarios are postulated to the extent conceivable in the reactor under consideration and analyzed using best estimate system thermal-hydraulics code RELAP5/Mod3.2. It is found that the various passive systems incorporated enable the reactor to tolerate the postulated accident conditions without causing severe plant conditions and core degradation.
Vikas Jain,A. K. Nayak,M. Dhiman,P.P. KULKARNI,P. K. Vijayan,K.K. Vaze 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.5
Pressing demands of economic competitiveness, the need for large-scale deployment, minimizing the need of human intervention, and experience from the past events and incidents at operating reactors have guided the evolution and innovations in reactor technologies. Indian innovative reactor ‘AHWR’ is a pressure-tube type natural circulation based boiling water reactor that is designed to meet such requirements, which essentially reflect the needs of next generation reactors. The reactor employs various passive features to prevent and mitigate accidental conditions, like a slightly negative void reactivity coefficient, passive poison injection to scram the reactor in event of failure of the wired shutdown systems, a large elevated pool of water as a heat sink inside the containment, passive decay heat removal based on natural circulation and passive valves, passive ECC injection, etc. It is designed to meet the fundamental safety requirements of safe shutdown, safe decay heat removal and confinement of activity with no impact in public domain, and hence, no need for emergency planning under all conceivable scenarios. This paper examines the role of the various passive safety systems in prevention and mitigation of severe plant conditions that may arise in event of multiple failures. For the purpose of demonstration of the effectiveness of its passive features, postulated scenarios on the lines of three major severe accidents in the history of nuclear power reactors are considered, namely; the Three Mile Island (TMI), Chernobyl and Fukushima accidents. Severe plant conditions along the lines of these scenarios are postulated to the extent conceivable in the reactor under consideration and analyzed using best estimate system thermal-hydraulics code RELAP5/Mod3.2. It is found that the various passive systems incorporated enable the reactor to tolerate the postulated accident conditions without causing severe plant conditions and core degradation.
Singh, Rani,Jain, Preeti,Pandey, N.K.,Saxena, V.K.,Saxena, M.,Singh, K.B.,Ahmed, K.A.,Singh, R.P. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.7
In the present study, the impact of Salmonella Typhimurium on cell-mediated immunity (CMI) was investigated in 5 week-old immuno divergent broiler lines selected for the high and low response to phytohemagglutinin-P. The immune response was assessed in peripheral-blood mononuclear cells (PBMCs) induced with Salmonella Typhimurium at different time intervals (0 h, 0.5 h, 2 h, 4 h, 6 h, 12 h and 24 h). The differential mRNA expression patterns of IFN-${\gamma}$, IL-2 and iNOS were evaluated by quantitative real time PCR. In-vitro production of nitric oxide (NO) was also estimated in the culture supernatant and correlated with iNOS mRNA expression. Present study showed higher production of NO in the high cell-mediated line (HCMI) as compared to the low cell-mediated line (LCMI) upon stimulation with Salmonella Typhimurium. Correspondingly, higher mRNA expression of iNOS and IFN-${\gamma}$ were observed in high response birds (HCMI); but IL-2 was down regulated in this line compared to the low response birds (LCMI). Significantly (p<0.05) higher expression of iNOS, IFN-${\gamma}$ and higher production of NO in high line indicated that the selection for PHA-P response might be employed for increasing the immune competence against Salmonella Typhimurium in chicken flocks.
Measurements of Cesium Radioisotopes in Cesium Compounds
Y.D.Kim,U.K.Kang,J.M.Choi,H.K.Jang,R.K.Jain,S.C.Kim,S.K.Kim,T.Y.Kim,이현수,S.E.Lee,H.Park,I.H.Park,원은일,H.S.Won,H.Y.Yang,M.S.Yang,M.J.Hwang,H.J.Kim,Y.J.Kwon,J.H.Lee,I.S.Cho,D.H.Choi,S.H.Noh,I.T.Yu,J.H.Kim 한국물리학회 2002 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.40 No.3
We have measured impurity levels of radioactive isotopes, especially 137Cs and 134Cs , in various cesium compounds using HPGe detectors for the rst time. The 137Cs contamination levels of cesium iodide (CsI) powder samples that are commercially available were between 9.7 mBq/kg and 80 mBq/kg. With these levels of the contamination, 137Cs will be the most serious background source in the low energy region E < 100 keV for CsI crystal. An upper limit of the 137Cs contamination level in pollucite powder, from which CsI powders are extracted, was set to be 5.8 mBq/kg at a 90 % condence level. It should be possible to fabricate the CsI crystal with much less 137Cs contamination than the currently available CsI crystal.
Electron-Electron Interactions based Metal-Insulator Transition in Ga Doped ZnO Thin Films
R V Muniswami Naidu,A Subrahmanyam,A Verger,M K Jain,S V N Bhaskara Rao,S N Jha,D M Phase 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.4
We report on the charge carrier transport mechanisms of undoped and Ga doped (2 wt. % and 4 wt. %)ZnO thin films grown by pulsed dc magnetron sputtering technique. Temperature dependent resistivity measurements showed typical semiconducting behaviour for undoped ZnO thin films where as Ga doped ZnO thin films showed metallic nature at higher temperatures and insulating nature with a metal to insulator transition at lower temperatures. The observed transition temperatures are 91 K and 140 K for 2 wt. % and 4 wt. %Ga doped ZnO films respectively. The observed metal insulator transition is attributed to the electron-electron interactions at low temperatures. The variations in the transition temperatures are explained based on the disorderness induced in the system due to the doping effect. ZnO doped with 4 wt. % Ga showed the lowest resistivity of 5.7 × 10−4Ω cm with a carrier concentration of 1.2 × 1021/cm3. Undoped and doped ZnO thin films are about 90% transparent in the visible region. Blue shift is observed in the absorption edge with the effect of doping and it is explained based on B-M shift. The Fermi level measured from valance band spectroscopy showed a shift of +0.6 eV for 2 wt. % Ga doped ZnO thin film and +0.7 eV for 4 wt. %Ga doped ZnO thin film compared to the Fermi edge of undoped ZnO thin films. This ascertains the movement of Fermi level in to the conduction band with the effect of doping.
Dark Matter Search Experiment with CsI(Tl) Crystal
김영덕,T. Y. Kim,D. H. Choi,J. M. Choi,한인식,M. J. Hwang,R. K. Jain,W. G. Kang,H. J. Kim,S. C. Kim,S. K. Kim,Y. J. Kwon,E. K. Lee,H. S. Lee,J. H. Lee,J. I. Lee,M. H. Lee,S. E. Lee,D. S. Lim,S. H. Noh,H. Pa 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.43 No.I
We are preparing an experiment for dark matter (WIMP) search using CsI(Tl) crystal. The detection threshold of a large CsI(Tl) crystal coupled with green extended PMTs was down to 2 keV, and the pulse shape discrimination power of the crystal shows better separation of nuclear recoil from background electron signals than NaI(Tl). With these characteristics, CsI(Tl) is another good material for WIMP search experiment. The disadvantage of CsI(Tl) is the internal background from cesium and rubicium ratioisotopes. In this report, the measurements and reduction of these ratioisotopes are described, and a perspective for the experiment is presented.
Studies of hypro-mellose (HPMC) functionalized ZnS:Mn fluorescent quantum dots
Jain, A.,Jain, A.,Panwar, S.,Singh, R.,Singhal, M.,Sharma, J. K.,Ahuja, R.,Jeon, H. C.,Kang, T. W.,Kumar, S. Springer Science + Business Media 2017 Journal of materials science. Materials in electro Vol.28 No.2
<P>Fluorescent ZnS:Mn quantum dots coated with hypro-mellose (HPMC) were synthesized by using simple and facile chemical precipitation technique in which HPMC acts as a novel organic surfactant to passivate the surface, to tune the optical properties and also to functionalize the surface of quantum dot for a futuristic controlled drug release applications. Morphological and optical characterizations were done to see the effect of HPMC coating on ZnS: Mn quantum dots. Structural and morphological studies was done by using XRD and TEM respectively. XRD studies confirms the pure zinc blende phase for all the samples. TEM studies shows that HPMC is efficiently doing the surface passivation in doped quantum dots. Optical studies were done by using UV-visible, FTIR and time resolved photoluminescence. UV-visible studies shows that quantum confinement effect is more prominent and also tunable in case of HPMC coated manganese doped ZnS quantum dots. FTIR studies confirms the functionalization of HPMC on the surface of doped ZnS quantum dots. Laser induced time resolved photoluminescence studies were also done to see the effect of HPMC on the photoluminescence intensity of doped quantum dots. Time resolved studies clearly shows the much desired luminescence stability of the HPMC coated quantum dots. It is observed that both the structural and optical characteristics have strong dependence on capping concentration. As HPMC is a very important viscoelastic polymer and organic surfactant used in various types of drug formulations, these studies opens a new way in the area of efficient drug delivery, controlled drug release and targeting.</P>
Gopal K.,Gupta D.N.,Jain A.,Hur M.S.,Suk H. 한국물리학회 2021 Current Applied Physics Vol.25 No.-
We investigate the parameters of accelerated electron bunch in laser wakefield acceleration (LWFA), when a skewed laser pulse propagates through a plasma in the presence of a transverse magnetic field. Two dimensional particle-in-cell (2D-PIC) simulations have been performed under the consideration of pulse skewness parameter (sα = τl/τt) that is defined as the ratio of leading (τl) to trailing pulse edge (τt) duration. The injected charge is estimated as 23 pC for the laser strength parameter a0 = 2 when sα changes from 1 to 0.45 at a laser propagation distance of 1.5 mm with 50T magnetic field. The electron beam emittance reduces about 50% when leading edge of the pulse becomes two-fold sharper (sα = 0.45) with 50T magnetic field. Energy spread of accelerated electron bunch is also reduced from 18 to 6.6%. Hence, in the presence of a transverse magnetic field, the laser pulse skewness can significantly improve the quality of the accelerated electron bunch (i.e. charge, mean energy and emittance) in laser wakefield acceleration.