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Response of Photonic Hydrogels of Homogeneous Particles to Uranyl Ions in Aqueous Solutions

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Photonic Sensors 2023年第4期13卷 50-61页

作者： R.G.JOSHI Deepak K.GUPTA P.AMESH P.K.PARIDA T.R.RAVINDRAN Materials Science Group Indira Gandhi Centre for Atomic ResearchA CI of Homi Bhabha National InstituteKalpakkam 603102India Materials Chemistry and Metal Fuel Cycle Group Indira Gandhi Centre for Atomic ResearchA CI of Homi Bhabha National InstituteKalpakkam 603102India Metallurgy and Materials Group Indira Gandhi Centre for Atomic ResearchA CI of Homi Bhabha National Institute(HBNI)Kalpakkam 603102India

We study here the response of photonic hydrogels(PHs),made of photonic crystals of homogeneous silica particles in polyacrylamide hydrogels(SPHs),to the uranyl ions 22 UO_(2)^(2+) in aqueous *** is found that the reflection spectra of the SPH show a peak due to the Bragg diffraction,which exhibits a blue shift in the presence of 22 UO_(2)^(2+).Upon exposure to the SPH,22 UO_(2)^(2+)gets adsorbed on the SPH and forms complex coordinate bonds with multiple ligands on the SPH,which causes shrinking of hydrogel and leads to the blue shift in the diffraction *** amount of the blue shift in the diffraction peak increases monotonically up to 22 UO_(2)^(2+)concentrations as high as 2300μ*** equilibration time for the shift in the Bragg peak upon exposure to 22 UO_(2)^(2+)is found to be~30 *** results are in contrast to the earlier reports on photonic hydrogels of inhomogeneous microgel particles hydrogel(MPH),which shows the threshold 22 UO_(2)^(2+)concentration of~600μM,below which the diffraction peak exhibits a blue shift and a change to a red shift above *** equilibration time for MPH is~300 *** observed monotonic blue shift and the faster time response of the SPH to 22 UO_(2)^(2+)as compared to the MPH are explained in terms of homogeneous nature of silica particles in the SPH,against the porous and polymeric nature of microgels in the *** also study the extraction of 22 UO_(2)^(2+)from aqueous solutions using the *** extraction capacity estimated by the arsenazo-III analysis is found to be 112 mM/kg.

关键词： Photonic hydrogels uranium extraction and monitoring arsenazo-Ⅲ-uranium complex polyacrylamide hydrogel UV-visible spectroscopy

Thermophysical properties of uranium-europium mixed oxides

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Journal of Advanced Ceramics 2015年第4期4卷 253-259页

作者： R.VENKATA KRISHNAN R.BABU Abhiram SENAPATI G.JOGESWARARAO K.ANANTHASIVAN Fuel Chemistry Division Indira Gandhi Centre for Atomic ResearchKalpakkam-603102Tamil NaduIndia

Uranium-europium mixed oxides(U_(1-y)Euy)O_(2-x)(y=0.2-0.8)were prepared by the citrate gel combustion technique and characterized by X-ray diffraction(XRD).Single phase fluorite structure was observed in those solid solutions with y≤*** solid solutions with y>0.6 were found to be biphasic,with the second phase being cubic *** capacity and enthalpy increment measurements were carried out by using differential scanning calorimeter(DSC)and drop calorimeter in the temperature range 298-800 K and 800-1800 K,***,pm C values at 298 K for(U_(1-y)Euy)O_(2-x)(y=0.2,0.4,0.6)are 64.8,64.6,and 63.5 J·K^(-1)·mol^(-1),*** anomalous increase was observed in the heat capacity in all of the solid solutions with the onset temperature around 950 *** could be attributed to the contribution from Frenkel pair oxygen *** the excess heat capacity data,the enthalpy for the formation of these defects was computed and found to be in the range of 2.10±0.02 eV.

关键词： uranium europium solid solution calorimetry heat capacity Frenkel defects

Study on hydrogen assisted cracking susceptibility of HSLA steel by implant test

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Defence Technology（防务技术） 2016年第6期12卷 490-495页

作者： Gopa CHAKRABORTY R. REJEESH S.K. ALBERT Materials Technology Division Indira Gandhi Centre for Atomic Research Kalpakkam 603102 India National Institute of Technology Surathkal India

DMR-249 A is an indigenously developed high strength low alloy steel for Indian ship building industry for making ship-hull and is extensively used in the construction of war ships and submarines. Welding electrodes conforming to SFA 5.5 AWS E8018 C1 has been indigenously developed for welding of this steel using shielded metal arc welding process. In the present study, susceptibility to hydrogen assisted cracking of DMR-249 A steel welds made using this electrode has been assessed using implant test. Implant tests were conducted using this electrode at two different levels of diffusible hydrogen, measured using gas chromatography technique. It is observed that both the steel and the welding consumable are not susceptible to hydrogen assisted cracking even with a high diffusible hydrogen level of 9 m L/100 g of weld metal. In implant tests, specimen did not fracture even after loading to stress levels higher than the yield strength of the base metal. The good resistance of this steel and the welding consumable, even with high levels of diffusible hydrogen, is attributed to absence of a susceptible microstructure in both the weld metal and heat affected zone. Hence, this study shows that, in the absence of a susceptible microstructure, hydrogen assisted cracking is unlikely to occur even if hydrogen level is high. It also confirms that in welding of DMR-249 A with indigenously developed E8018 C1 electrode, hydrogen assisted cracking is not a concern and no preheating is required to avoid it during welding.

关键词： HSLA steel Hydrogen assisted cracking Diffusible hydrogen Implant test Lower critical stress

Investigation of enhancement in planar fast neutron detector efficiency with stacked structure using Geant4

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Nuclear Science and Techniques 2017年第11期28卷 154-163页

作者： Shivang Tripathi Chandrakant Upadhyay C. P. Nagaraj K. Devan A. Venkatesan K. Madhusoodanan Homi Bhabha National Institute AnushaktinagarMumbai 400094 India indira gandhi centre for atomic research Kalpakkam 603102 India

Geant4 based Monte Carlo study has been carried out to assess the improvement in efficiency of the planar structure of Silicon Carbide(SiC)-based semiconductor fast neutron detector with the stacked structure. A proton recoil detector was simulated, which consists of hydrogenous converter, i.e., high-density polyethylene(HDPE) for generating recoil protons by means of neutron elastic scattering(n, p) reaction and semiconductor material SiC, for generating a detectable electrical signal upon transport of recoil protons through it. SiC is considered in order to overcome the various factors associated with conventional Si-based devices such as operability in a harsh radiation environment, as often encountered in nuclear facilities. Converter layer thickness is optimized by considering 10~9 neutron events of different monoenergetic neutron sources as well as ^(241)Am-Be neutron spectrum. It is found that the optimized thickness for neutron energy range of 1–10 MeV is ~400 μm. However, the efficiency of fast neutron detection is estimated to be only 0.112%,which is considered very low for meaningful and reliable detection of neutrons. To overcome this problem, a stacked juxtaposition of converter layer between SiC layers has been analyzed in order to achieve high efficiency. It is noted that a tenfold efficiency improvement has been obtained—1.04% for 10 layers stacked configuration vis-à-vis 0.112% of single converter layer detector. Further simulation of the stacked detector with respect to variable converter thickness has been performed to achieve the efficiency as high as ~3.85% with up to 50 stacks.

关键词： Geant4 Fast neutron detector Silicon carbide Recoil proton Stacked detector

Transient Evolution of Inter Vessel Gap Pressure Due to Relative Thermal Expansion Between Two Vessels

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Journal of Thermal Science 2002年第3期11卷 220-225页

作者： K.Natesan P.Selvaraj P.Chellapandi S.C.Chetal Mechanics and Hydraulics Division Indira Gandhi Centre for Atomic Research Kalpakkam India

In a typical liquid metal cooled fast breeder reactor (LMFBR), a cylindrical sodium filled main vessel, which carries the internals such as reactor core, pumps, intermediate heat exchangers etc. is surrounded by another vessel called safety vessel. The inter vessel gap is filled with nitrogen. During a thermal transient in the pool sodium, because of the relative delay involved in the thermal diffusion between MV and SV, they are subjected to relative thermal expansion or contraction between them. This in turn results in pressurisation and depressurisation of inter vessel gap nitrogen respectively. In order to obtain the external pressurization for the buckling design of MV, transient thermal models for obtaining the evolutions of MV, SV and inter gap nitrogen temperatures and hence their relative thermal expansion and inter vessel gap pressure have been developed. This paper gives the details of the mathematical model, assumptions made in the calculation and the results of the analysis.

关键词： transient thermal calculation relative thermal expansion LMFBR Runga Kutta method.

Influence of Structural Modification on Work-hardening Behaviour of Type 316 Stainless Steel

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Journal of Materials Science & Technology 1998年第5期14卷 399-401页

作者： K.G.Samuel S.L.Mannan and P.Rodriguez (Metallurgy and Materials Group, indira gandhi centre for atomic research, kalpakkam 603 102, India) Metallurgy and Materials Group Indira Gandhi Centre for Atomic Research Kalpakkam 603 102 India

Work-hardening behaviour of type 316 austenitic stainless steel having difFerent initial dislocation structures introduced by swaging to various levels is analysed by a simplified Kock's model which takes into account the structural changes through the dislocation accumulation and annihilation process during deformation. The dislocation accumulation and annihilation factors show a temperature and structure dependence. The dislocation annihilation factor shows a plateau or decreasing tendency in the dynamic strain ageing (DSA) temperature range. This is attributed as either due to dislocation accumulation being more pronounced than dislocation annihilation or as due to precipitates being formed at DSA temperatures acting as obstacles to dislocation motion in the DSA temperature range.

关键词： Work Influence of Structural Modification on Work-hardening Behaviour of Type 316 Stainless Steel

Pitting and stress corrosion cracking studies on AISI type 316N stainless steel weldments

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Defence Technology（防务技术） 2018年第3期14卷 226-237页

作者： Anita Toppo M.G.Pujar N.Sreevidya John Philip Corrosion Science and Technology Division Indira Gandhi Centre for Atomic Research Materials Development and Technology Division Indira Gandhi Centre for Atomic Research

Pitting and stress corrosion cracking(SCC) studies on the 316 N stainless steel(SS) weldments in aswelded(AW) and thermally aged(solution annealing(SA), 550C/4 h and 750C/1 h) conditions were carried out in acidic and acidic chloride media. Pitting corrosion and SCC resistance was the highest for SA weldment, which was attributed to homogenization of microstructural and microchemical heterogeneities during solution annealing. SA specimen showed the most stable passive film as compared to AW weldment because of higher amount of delta-ferrite in AW weld metal, which resulted in an increased heterogeneity and inferior SCC resistance in AW. Stability of passive film was found to be adversely affected due to heat treatments(at 550C/4 h and 750C/1 h) because of the precipitation of carbide and sigma phases.

关键词：压力腐蚀不锈钢 AISI 焊接金属 SCC 稳定性氯化物微结构

Laser-Heated Diamond-Anvil Cell (LHDAC) in Materials Science research

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Journal of Materials Science & Technology 2003年第6期19卷 518-525页

作者： N.V.Chandra Shekar P.Ch.Sahu K.Govinda Rajan Materials Science Division Indira Gandhi Centre for Atomic Research Kalpakkam 603 102 Tamil Nadu IndiaMaterials Science Division Indira Gandhi Centre for Atomic Research Kalpakkam 603 102 Tamil Nadu IndiaMaterials Science Division Indira Gandhi Centre for Atomic Research Kalpakkam 603 102 Tamil Nadu India

Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.

关键词： Laser heating Diamond-anvil cell High pressure-high temperature Materials synthesis,Melting phenomena Phase equilibria

Investigations on luminescence of rare earths doped CaTiO_3:Pr^(3+) phosphor

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Journal of Rare Earths 2010年第4期28卷 488-492页

作者： N. Suriyamurthy B.S. Panigrahi Radiological Safety Division Technical Services Division Indira Gandhi Centre for Atomic Research Kalpakkam-603 102 India

Calcium titanate doped with praseodymium was prepared through solid state reaction and it exhibited intense red emission at 612 nm. Phosphors were characterized for photoluminescence, thermo-luminescence and afterglow emissions. Study of effects of rare earths on photoluminescence as well as afterglow intensity was reported. Presence of gadolinium enhanced luminescence. Presence of some monovalent ions enhanced both afterglow and photoluminescence emission. Thermo-luminescence glow curves were analyzed and ...

关键词： perovskites calcium titanates red afterglow rare earths