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1.
R. M. Sawant R. K. Rastogi N. K. Chaudhuri 《Journal of Radioanalytical and Nuclear Chemistry》1998,238(1-2):203-206
The paper presents a radiokinetic study on the appearance and growth of*Fe2S3,*Fe(OH)3,*Fe2(C2O4)3,*Fe(IO3)3 crystals in a colloidal medium of agar and gelatine. The values of the diffusion constants through gels of55+59Fe3+ radioactive cations and of the rate of global growth process of these crystals in agar or gelatine were calculated using
the experimental data. A new method for the determination of the starting time for the complex nucleation process was proposed.
The formation rate of crystals under study decreases in the order:*Fe(OH)3>*Fe(IO3)3>*Fe2S3>*Fe2(C2O4)3, in agar medium and*Fe(OH)3>*Fe(IO3)3>*FeC2O4)3>*FeS3, in gelatine medium. 相似文献
2.
R. M. Sawant G. H. Rizvi N. K. Chaudhuri S. K. Patil 《Journal of Radioanalytical and Nuclear Chemistry》1985,89(2):373-378
Fluoride complexing of Np(V) has been studied using fluoride ion selective electrode (F-ISE). Free fluoride ion concentrations in the presence of Np(V) were measured at 0.1 and 1.0M ionic strength. The data were used to calculate the stability constant of the fluoride complex of Np(V) and the values obtained are reported here. 相似文献
3.
Kamat R. V. Sawant R. M. Mhatre H. R. Chaudhuri N. K. Vaidya V. N. 《Journal of Radioanalytical and Nuclear Chemistry》1998,238(1-2):33-41
pH titration curves generated by slow addition of alkali to solutions containing varying concentrations of uranyl nitrate
and nitric acid were studied using an autotitrator linked to a personal computer. A procedure with multiple choice of equations
has been developed for the estimation of free acid, nitrate and uranium in pure uranyl nitrate solution by a single titration.
The technique provides a simple single-step method with required accuracy and precision for the simultaneous estimation of
the three quantities in the uranyl nitrate feed solution of the sol-gel process for making UO3 microspheres. The relative standard deviations in the determination of uranium and nitrate were ±0.82% and ±1.52%, respectively,
in 15 determinations. 相似文献
4.
R. C. Sharma P. K. Kalsi L. R. Sawant S. Vaidyanathan R. H. Iyer 《Journal of Radioanalytical and Nuclear Chemistry》1988,128(1):81-16
An iterative computational method for the determination of metal ions in aqueous solutions which form reversible couples such as Fe(II)/Fe(III), Pu(III)/Pu(IV) etc. by controlled potential coulometry has been developed. The method involves carrying out the electrolysis to about 95–97% and calculating the total amount present in the sample by an iterative computational method. The method utilizes the direct application of the Nernst equation. The important criterion to be met is that the coulogram of the couple should strictly obey the Nernst equation. The validity of the method has been checked by analyzing about 50 samples of a standard iron solution. Results of analysis of mixtures of Pu and Fe by the iterative technique show that the interference of Fe can almost entirely be eliminated. However, analysis of Pu samples by this procedure gives results about 2–3% lower than the expected value. A careful examination of the experimental coulograms of Pu in lM HClO4 indicates a slight deviation from the theoretical coulogram, where as those of Fe match exactly. 相似文献
5.
S. S. Suryavanshi U. R. Ghodake A. M. Sankpal S. V. Kakatkar R. S. Patil S. R. Sawant 《Czechoslovak Journal of Physics》1995,45(6):509-516
For the ferrites Ni
x
Cd1–x
Fe2O4 (x=0.3, 0.4,1) the lattice parameter, grain size, electrical resistivity, initial permeability, Curie temperature and squareness of the magnetization curve were measured. The results are discussed in terms of the model of the canted spin structure taking into account the domain structure of the polycrystalline ferrite. 相似文献
6.
The optimum conditions for the extractive spectrophotometric determination of dioxouranium(VI) with hexamethyleneiminecarbodithioate(HMICdt) have been established. Dioxouranium(VI) reacts with this ligand at pH 4.5 to form a yellowish-orange uncharged 12 metal-ligand complex which can be extracted by chloroform. The calibration graph was linear in the range of 1–20 g ml–1 of dioxouranium(VI) at 335 nm. The molar absorptivity of the extracted species is 5.952×103 l mol–1 cm–1 with Sandell's sensitivity of 0.04 g cm–2. The average of 10 determinations of dioxouranium was 49.75 g for the samples containing 50 g of U(VI) and the variation from the mean at 95% confidence limit was 49.75±0.5955. 相似文献
7.
Debojyoti Bag Prof. Sanghapal D. Sawant 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(4):1165-1218
Heteroarene-tethered functionalized alkynes are multipotent synthons in organic chemistry. This detailed Review described herein offers a thorough discussion of the metamorphosis of heteroarene-tethered functionalized alkynes, an area which has earned much attention over the past decade in the straightforward synthesis of architecturally complex heterocyclic scaffolds in atom and step economic manner. Depending upon the variety of functionalized alkynes, this Review is divided into multiple sections. Amongst the vast array of synthetic transformations covered, dearomatizing spirocyclizations and cascade spirocyclization/rearrangement are of great interest. Synthetic transformations involving the heteroarene-tethered functionalized alkynes with scope, challenges, limitations, mechanism, their application in the total synthesis of natural products and future perceptions are surveyed. 相似文献
8.
Reaction of TFA with sodium borohydride in THF is a loss of thermal control involving the evolution of Hydrogen gas. The investigation of the process by RC1e and ARSST showed that the criticality class of the reaction is dependant on the addition of TFA. Heat of reaction (Q r), adiabatic temperature rise (ΔT ad), and MTSR data are obtained from RC1e experiment. Exothermic onset temperature, Pressure rise, and self heat rate data are obtained from ARSST experiments. The correlation of these data was utilized to define the criticality class of the reaction under different conditions. The reaction with uncontrolled addition of TFA falls in the undesirable criticality class 5. Vent size data are obtained from the adiabatic calorimeter for undesirable reaction. The criticality class can be changed to class 2 with controlled addition. Accordingly, interlock system to control the undesired reaction and appropriate vent relief system are provided. 相似文献
9.
10.
Xiong JY Liu XY Sawant PD Chen SB Chung TS Pramoda KP 《The Journal of chemical physics》2004,121(24):12626-12631
It is generally agreed that, in most cases, surfactants are required to obtain stable polymeric nanoparticle dispersions. Here, we report a method which can be used to produce surfactant free yet stable polymeric nanoparticle dispersions. This method is based on explored mechanism of selective solvation of nanoparticles and EPD (electron pair donor)/EPA (electron pair acceptor) complexes formed among solvent and nonsolvent molecules. Using polyimide P84 (copolyimide 3,3(') 4,4(')-benzophenone tetracarboxylic dianhydride and 80% methylphenylene diamine+20% methylene dianiline) as the model polymer, this mechanism was realized through a combined liquid-liquid phase separation and solvent/nonsolvent mixing technology. Surfactant-free polyimide nanoparticles (<100 nm) were produced. Experimental details and principles of this technology were given based on the ternary diffusion, the liquid-liquid phase separation and the advanced nucleation and growth theory. Two types of methods [denoted as the forward titration method and the backward titration (BT) method] were examined. It was found that the BT method is extremely helpful to prepare polyimide nanoparticles (<100 nm). As another important aspect, explored stabilization mechanism of the resultant nanoparticle dispersions was supported by the comparative experiments, implying that selective solvation of nanoparticles and EPD/EPA complexes may play key roles in stabilization. 相似文献