Studies on Separation of 90Y and 90Sr Separation from Hydrochloric Acid Solutions Using TODGA as the Extractant by SLM Method

AbstractYttrium-90 is an important radionuclide known for its therapeutic application in nuclear medicine. Solvent extraction studies with N,N,N’,N’-tetra-octyldiglycolamide (TODGA) has shown that Y(III) is well extracted in 6M HCl while at the same time, extraction of Sr(II) is very low leading to a separation factor (DY/DSr = 60,000). This property of TODGA can be exploited for the separation of Y from Sr. The aim of this present work is to produce carrier free 90Y by using Supported Liquid Membrane (SLM) based separation of Y and Sr with TODGA as the carrier. Solvent extraction studies with various diluents viz. 1-decanol, xylene, MIBK, chloroform etc. indicated that xylene and n-dodecane are most suitable as S.F. >50,000 are obtained. Based on the results, a SLM based separation scheme was developed using 0.1M TODGA in xylene loaded on a microporous PTFE membrane as a polymeric support and 6M HCl as feed and 0.01M HCl as strip phase. The results appear promising for the development of SLM based Y-90 generator. The purity of the product was ascertained by the half life method

Genetic algorithm fuzzy clustering using GPS data for defining level of service criteria of urban streets

Developing countries like India need to have proper Level of Service (LOS) criteria for various traffic facilities as this helps in planning, design of transportation projects and also allocating resources to the competing projects. The LOS analysis for urban street followed in India is an adaptation of HCM-2000 methodology but the methodology is relevant for developed countries having homogenous traffic flow. In this research an attempt has been made to establish a framework to define LOS criteria of urban street in Indian context keeping in mind the geometric and surrounding environmental characteristics. Defining LOS criteria is basically a classification problem for which cluster analysis is a suitable technique can be applied. In this research a hybrid algorithm comprising of Genetic Algorithm (GA) and Fuzzy C-mean is utilized. As input to the clustering algorithm GA-Fuzzy a lot of speed data is required. From literature review GPS is found to be a suitable tool for collecting second by second speed data and GIS is suitable in handling large amount of speed data. The clustering algorithm is used twice in this study. First the GA-Fuzzy algorithm was used to classify Free Flow Speed (FFS) data into number of classes in order to get the FFS ranges of different urban street classes. To determine the optimal number of cluster using FFS data five cluster validation parameters are considered. After getting the FFS ranges for different urban street classes the same GA-Fuzzy algorithm is used on average travel speed data collected during both peak and off-peak hours to determine the speed ranges of different LOS categories. From this analysis the free flow speed ranges for different urban street classes and the speed ranges for different LOS categories are defined and the values are found to be lower than that suggested by HCM-2000. The coherence of the clustering result in classification of urban streets into four classes and speed values into six LOS categories is agreed with the physical and surrounding environmental characteristics of road segments under the study area. From this analysis it is also found that good LOS can’t be expected from urban street segment for which physical and surrounding environmental characteristics are not good

Assessment of III-V FinFETs at 20nm Node: A Process Variation Analysis

AbstractThe endless miniaturization of Si based MOSFETs has the key for driving the electronic revolution. However, scaling of the channel length is the enormous challenge to preserve the performance in terms of speed, power and electrostatic integrity at each technology nodes. Subsequently all researchers have been analyzing new device materials and architectures to fix this challenge. After continuous development in the areas of devices and materials have lastly conveyed III-V MOSFETs with high channel mobility. This paper is a discussion about the impact of fin height (HFin) and fin width (WFin) of a GaAs-FinFET, which affect the reliability of the device in view of various performance measures. A detailed analysis about the impact of geometry parameters like (HFin) and (WFin) on the static or low frequency performances like threshold voltage (Vth), on-off ratio (Ion/Ioff), power dissipation, subthreshold slope (SS), transconductance (gm), early voltage (VEA), gain (AV) and dynamic or high frequency performances as gate capacitance (Cgg), cut-off frequency (fT), delay (CV/I), energy (CV2), energy delay product (EDP) are systematically presented

Indian Agriculture – Journey from Begging Bowl to Sustainable Food Security

63-69ICAR is responsible for planning, coordinating and promoting agricultural research, technology development, knowledge dissemination and education in the country

Extraction of Scandium (III) from acidic solutions using organo-phosphoric acid reagents: A comparative study

Comparative and synergistic solvent extraction of Sc(III) using two phosphoric acidic reagents such as di-(2-ethyhexyl) phosphoric acid and 2,4,4,tri-methyl,pentyl-phosphinic acid was investigated. Slope analysis method suggests a cation exchange reaction of Sc(III) with both extractants at a molar ratio of extractant: Sc(III) = 2.5:1 at equilibrium pH< 1.5. The plot of log D vs. log [Extractant] yield the slope (n) value as low as 1.2-1.3 and as high as n=7 at low and high extrcatant concentration level, respectively. Extraction isotherm study predicted the need of 2 stages at A: O=1:4 and A: O=1:3 using 0.1 M D2EHPA and 0.1 M Cyanex 272, respectively. Stripping of Sc (III) was carried out at varied NaOH concentration to ascertain the optimum stripping condition for effective enrichment of metal. The predicted stripping condition (2)-stages with A: O=1:3 and 1:4 for D2EHPA and Cyanex 272, respectively) obtained from Mc-Cabe Thiele plot was further validated by 6-cycles CCS study. An actual leach solution of Mg-Sc alloy bearing 1.0 g/L of Sc (III), 2.5 g/L of Mg and 0.2 M HCl was subjected for selective separation of Sc at the optimum condition. The counter current simulation (CCS) study for both extraction and stripping of actual solution resulted quantitative separation of Sc with ∼12 fold enrichment. The organic phase before and after loading of Sc (III) along with the diluents was characterized by FTIR to ascertain the phase transportation of Sc (III)

Role of additives in electrochemical deposition of ternary metal oxide microspheres for supercapacitor applications

A simple two-step approach has been employed to synthesize a cobalt–nickel–copper ternary metal oxide, involving electrochemical precipitation/deposition followed by calcination. The ternary metal hydroxide gets precipitated/deposited from a nitrate bath at the cathode in the catholyte chamber of a two-compartment diaphragm cell at room temperature having a pH ≈ 3. The microstructure of the ternary hydroxides was modified in situ by two different surfactants such as cetyltrimethylammonium bromide and dodecyltrimethylammonium bromide in the bath aiming for enhanced storage performance in the electrochemical devices. The effect of the surfactant produces a transition from microspheres to nanosheets, and the effect of micelle concentration produces nanospheres at a higher ion concentration. The ternary hydroxides were calcined at 300 °C to obtain the desired ternary mixed oxide materials as the electrode for hybrid supercapacitors. X-ray diffraction analysis confirmed the formation of the ternary metal oxide product. The scanning electron microscopy images associated with energy-dispersive analysis suggest the formation of a nanostructured porous composite. Ternary metal oxide in the absence and presence of a surfactant served as the cathode and activated carbon served as the anode for supercapacitor application. DTAB-added metal oxide showed 95.1% capacitance retention after 1000 cycles, achieving 188 F/g at a current density of 0.1 A/g, and thereafter stable until 5000 cycles, inferring that more transition metals in the oxide along with suitable surfactants at an appropriate micellar concentration may be better for redox reactions and achieving higher electrical conductivity and smaller charge transfer resistance. The role of various metal cations and surfactants as additives in the electrolytic bath has been discussed

Evaluation of several multiple diglycolamide-functionalized calix[4]arene ligands for the isolation of carrier free 90Y from 90Sr

Several diglycolamide-functionalized calix[4]arenes containing four and eight diglycolamide (DGA) moieties were evaluated for their relative extraction efficiencies towards Y(III) and Sr(II). Ligands containing four DGA units with n-propyl, iso-pentyl, and n-octyl groups at the amidic N atom adjacent to the calix[4]arene skeleton showed efficient extraction of Y(III) from 3 M HNO3. The extraction of Sr(II) was poor in all cases in the entire acidity range (0.1–6 M HNO3) studied. The ligands with a hydrogen atom and an n-propyl group at the concerning amidic N atom showed a very high separation efficiency as reflected in separation factor (S.F.=DY/DSr) values in the range of 105–106. A method was developed for the separation of carrier-free 90Y from a 90Y-90Sr mixture involving consecutive extraction–stripping cycles. The product purity was checked using half-life measurements. Two consecutive cycles of extraction and stripping were found to be sufficient for obtaining pure 90Y. The results obtained in the present studies were compared with those obtained previously using analogous ligands such as TODGA (N,N,N',N'-tetraoctyl diglycolamide), T2EHDGA (N,N,N',N'-tetra-2-ethylhexyl diglycolamide), and PC-88A (bis(2-ethylhexyl) phosphonic acid)

Model Analysis of Time Reversal Symmetry Test in the Caltech Fe-57 Gamma-Transition Experiment

The CALTECH gamma-transition experiment testing time reversal symmetry via the E2/M1 mulipole mixing ratio of the 122 keV gamma-line in Fe-57 has already been performed in 1977. Extending an earlier analysis in terms of an effective one-body potential, this experiment is now analyzed in terms of effective one boson exchange T-odd P-even nucleon nucleon potentials. Within the model space considered for the Fe-57 nucleus no contribution from isovector rho-type exchange is possible. The bound on the coupling strength phi_A from effective short range axial-vector type exchange induced by the experimental bound on sin(eta) leads to phi_A < 10^{-2}.Comment: 5 pages, RevTex 3.