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- Author or Editor: D. Shah x
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Abstract
The combination of lipophilic macrocyclic oxygen donors with the extractant thenoyltrifluoroacetone /HTTA/ has been shown to have a significant synergistic effect on the extractions of trivalent actinides and lanthanides. The results show that the nitrogen containing cryptand /222BB/ is a more effective synergist than the crown ether compound /15-C-5/ with only oxygen donors.
Abstract
The instrumental neutron activation analysis (INAA) of industrially important steel samples, viz. IS-226, IS-2002, IS-2062, SS-304, SS-310, SS-316 and of copper base alloys, viz. high brass, gun metal and copper-silver alloys is carried out with a 2 Ci252Cf neutron source. The copper and vanadium content of all the steel samples and manganese content of former three steel samples are estimated by measuring the gamma activity of66Cu,52V and56Mn radioisotopes, respectively, using a high purity germanium (HPGe) detector coupled to a 4 K multichannel analyzer (MCA). Similarly, the copper content of copper base alloys was also determined.
Abstract
Determination of 241Am/243Am ratios is required for vanous purposes including assay of Am by isotope dilution techniques. Alpha-spectrometry on electrodeposited sources is a preferred technique for this determination. However, there is an inherent problem of tail contribution which necessitates the use of suitable algorithms to account for the same. Recently, in the frame of a Coordinated Research Program (CRP) of the International Atomic Energy Agency (IAEA), WinALPHA software has been developed which is a combination of an asymmetrical Gaussian for the main part of the peak and a low energy function. Therefore, it was of interest to compare the use of this algorithm with the routinely used method, in our laboratory, based on geometric progression (G. P.) decrease. Since, there are no reference materials available commercially for 241Am/243Am ratios, synthetic mixtures covening a wide range (0.3 to 2.0) of 241Am/243Am α-activity ratios were used and un-ignited electrodeposited sources were prepared for α-spectrometry. The α-spectra obtained using PIPS detector, were evaluated using the two algonthms The 241Am/243Am α-activity ratios obtained were also compared with those determined by thermal ionization mass spectrometry (TIMS). An agreement of about 1% was obtained in the 241Am/243Am ratios determined by the two methods and also by using the two algorithms for α-spectrum evaluation.
Abstract
Determination of 238Pu in plutonium bearing fuels is required as a part of the chemical quality assurance of nuclear fuels. In addition, the determination of 238Pu is required in nuclear technology for many other applications, e.g., for developing isotope correlations and while using 238Pu as a spike (tracer) in isotope dilution α-spectrometry (IDAS). This determination usually involves the use of α-spectrometry on purified Pu sample. In view of the random errors associated with the counting statistics and the systematic errors due to (1) in-growth of 241Am in purified Pu sample and (2) tail contribution correction methodology in α-spectrometry, the precision and accuracy obtainable by α-spectrometry are limited. Thermal ionization mass spectrometry (TIMS) is generally used for the determination of different Pu isotopes other than 238Pu. This is due to the ubiquitous isobaric interference from 238U at 238Pu in TIMS. Recently, we have carried out studies on the formation of atomic and oxide ions of U and Pu by TIMS and developed a novel approach using interfering element correction methodology to account for the isobaric interference of 238U at 238Pu in TIMS. This methodology is based on the addition of 235U (enrichment >90 atom%) to Pu sample followed by the determination of 238U/235U atom ratio using UO+ ion and determination of Pu isotope ratios using Pu+ ion, from the same filament loading. The TIMS methodology was used for the determination of 238Pu in different Pu samples in U based nuclear fuels from PHWRs with 238Pu content about 0.2 atom%. The 238Pu determination was also carried out using α-spectrometry. This paper reports the results obtained by the two methods and presents the ments and shortcomings of the two approaches.
Abstract
A rapid method for simultaneous determination of fluorine and chlorine in radioactive liquid wastes with ion chromatography after pyrohydrolysis separation was proposed for routine analysis. The elements were separated from radioactive liquid wastes by pyrohydrolysis and were subsequently determined with ion chromatograpy. Total time taken to determine these elements is about 45 min including 30 min for the pyrohydrolysis and 15 min for ion chromatography. The results of recovery tests ranged 95% or above. The limits of detection for F and Cl are 0.5 and 0.8 mg kg−1, respectively.
Summary
An isocratic reversed-phase liquid chromatograpic assay method was developed for the quantitative determination of atorvastatin and aspirin (ASP) in combined dosage form. A Phenomenex Gemini C-18, 5-μm column with mobile phase containing 0.02 M potassium dihydrogen phosphate-acetonitrile-methanol (30:30:40, v/v/v) adjusted to pH 3 using o-phosphoric acid was used. The flow rate was 1.0 mL min−1 and effluents were monitored at 240 nm. The retention times (RTs) of atorvastatin calcium (ATV) and ASP were 10.5 and 3.8 min, respectively. ATV and ASP stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation, and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their RT values. Stressed samples were assayed using developed LC method. The proposed method was validated with respect to linearity, accuracy, precision, and robustness. The method was successfully applied to the estimation of ATV and ASP in combined capsule dosage forms.
Abstract
PbO based phosphate glasses having composition 40P2O5�12Al2O3�6B2O3�9PbO�xNa2O�(33−x)K2O (x=0−33) [F=Na/(Na+K)] have been prepared using conventional melt quench technique. Density, morphology, thermal expansion coefficient (α) and glass transition temperature (T g) were studied as a function of Na/(Na+K) ratio. Formation of transparent, bubble free and clear glass was observed up to x=18 mol%. Density was found to vary from 2.70 to 3.69 g cm−3. The significant changes were noticed in external morphologies at temperatures corresponding to softening, half ball and melting points under high temperature microscope for three compositions (x=0, 10 and 15 mol%). These glasses recorded the softening and half ball temperatures in the range 454–470�C and 523–576�C respectively and melting temperatures agree well with DTA studies within the experimental limits. Glass transition temperature showed a broad maxima while thermal expansion coefficient (TEC) a broad minima around Na/(Na+K)=0.54. This behaviour is explained on the basis of bond formation/phase separation.
