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International Review of Applied Sciences and Engineering
Authors:
K. S. Ajay Venkadesh
,
K. Harish Kumar
,
B. Hariharan
,
A. Arumugam
,
A. Nithish Kumar
,
P. Karthigai Priya
, and
S. Vanitha

Abstract

Raw materials requirement is foremost necessary in construction sector. Due to the increase in construction activities, the raw material utilization is also increased, which may lead to depletion of the resources. The usage of M sand also increases day by day. On the other side, waste disposal is posing a major threat to environment and human health. This paper shows the investigation carried out in manufacturing fly ash bricks made by utilizing vermicompost as an alternative material for M sand, the physical and chemical properties of M sand and vermicompost are studied and they seem to be the same. In this study, an attempt is made to check the feasibility of replacement of vermicompost for M sand in brick making. The brick specimens are casted as per the mix proportions and they are tested for strength and durability at the age of 28 days. It has been identified that the vermicompost replacement at 5% and 10%, the compressive strength of the brick is 7.90 and 7.31% respectively, which is found to be nearer to the strength of the control specimen and the water absorption for all the mixes of the brick casted were below 20% as per IS code. Inclusion of vermicompost in the fly ash bricks will tend to reduce the use of M sand.

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Inorganic ion-exchangers in radioactive waste management

Part XVI: Uptake of some metal phosphates (stannic and zirconium) for 134Cs

Journal of Radioanalytical and Nuclear Chemistry
Authors:
Shuddhodan P. Mishra
,
Diwakar Tiwari
,
Shailesh Kumar Prasad
,
R. S. Dubey
, and
Manisha Mishra

Summary  

The uptake of indigenously synthesized amorphous stannic and zirconium phosphate was assessed for, one of the important fission fragment, cesium from aqueous solutions using a radiotracer technique. A virtual increase in sorptive concentration (from 1.0 . 10-8 to 1.0 . 10-2 mol . dm-3) and pH (from 2.4 to 10.2) and temperature (from 303 to 333 K) enhanced the uptake of cesium on stannic phosphate. However, the extremely high degree of uptake of cesium on zirconium phosphate was almost unaffected with the dilution beyond 10-5 mol . dm-3 and pH (i.e., from 2.4 to 10.2) and temperature (from 303 to 323 K). Irreversible uptake occurring for these solids follow the Freundlich adsorption isotherm and the presence of several complexing agents viz., sulphate, phosphate, glycine and EDTA did not affect appreciably the uptake of cesium on zirconium phosphate but it did affect for stannic phosphate system. Both these solids showed good radiation stability towards a 11.1 GBq Ra-Be neutron source having neutron flux ca. 3.2 . 106 n . cm-2 . s-1 and associated with a nominalg-dose of ca. 1.72 Gy/h, at least for the uptake of cesium.

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Abstract  

Drinking water samples were collected from four different districts, namely Bhatinda, Mansa, Faridkot and Firozpur, of Punjab for ascertaining the U(nat.) concentrations. All samples were preserved, processed and analyzed by laser fluorimetry (LF). To ensure accuracy of the data obtained by LF, few samples (10 nos) from each district were analyzed by alpha spectrometry as well as by fission track analysis (FTA) technique. For FTA technique few μl of water sample was transferred to polythene tube, lexan detector was immersed in it and the other end of the tube was also heat-sealed. Two samples and one uranium standard were irradiated in DHRUVA reactor. Irradiated detectors were chemically etched and tracks counted using an optical microscope. Uranium concentrations in samples ranged from 3.2 to 60.5 ppb and were comparable with those observed by LF.

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Abstract  

Cross-linked hydrogel matrices immobilized with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HA), were prepared to investigate their application in the recovery of radionuclide from acidic waste solutions. Gamma-radiation was used to produce HA immobilized polyvinyl alcohol (PVA) hydrogels (HA-gel). The hydrogels with different characteristics such as: degree of cross-linking (by varying radiation dose) and quantity of extractant immobilized (by starting with aqueous PVA solution containing different amounts of HA), were synthesised. These HA-gels were investigated for solid-liquid phase extraction of U(VI), Pu(IV), Am(III) and some fission products, under various experimental conditions. The concentration of HNO3 in the aqueous phase was found to play an important role in the extraction of these radionuclei. Extraction of U(VI) was more favourable at lower concentration of HNO3 (∼0.001 to 0.5M), while at higher concentrations (∼0.5 to 3M HNO3), more than 90% of Pu(IV) present in the aqueous phase, could be extracted by the HA-gel. The extraction of Am(III) was also found predominant only at lower acidities (at pH∼2 and above). Under optimized conditions, maximum metal loading capacities obtained were 19±0.8 mg, 8±0.4 mg and 11±0.5 mg per gram of swollen HA-gel, for U(VI), Pu(IV) and Am(III), respectively. Under the experimental conditions, extractions of Cs(I) and Sr(II) were observed to be negligible. No leaching out of HA from the HA-gel particles was noted even after its repetitive use for the studied ten cycles of extraction and stripping experiments, as evident from its unchanged extraction efficiency.

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Abstract  

This paper describes Jet Entrainment Technique (JET) developed at Bhabha Atomic Research Centre (BARC) for the preparation of small microspheres of UO2 in the size range of 100±20 μm diameter. The UO2 microspheres were prepared by Internal Gelation Process (IGP) using selected feed solution compositions. Equipment development and the optimized process operations for obtaining more than 90% of high density UO2 microspheres in the desired size range are described.

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Abstract  

The applicability of zirconium phosphate-ammonium molybdophosphate (ZrP-AMP) for the efficient removal of cesium from aqueous acidic solutions by adsorption has been investigated. The adsorption data analysis was carried out using the Freundlich, Dubinin-Raduskevich (D-R) and Langmuir isotherms for the uptake of Cs in the initial concentration range of 3.75.10-5-7.52.10-3 mol.dm-3 on the ZrP-AMP exchanger from nitric acid medium. The mean free energy (E) values for the adsorption of Cs were obtained from the D-R isotherm. Equilibrium adsorption values at different temperatures have been utilized to evaluate the change in enthalpy, entropy and free energy (ΔH°, ΔS°, ΔG°). The adsorption of cesium on the ZrP-AMP exchanger was found to be endothermic.

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Abstract  

A simple and efficient method has been developed to preconcentrate natural protactinium from large quantity of monazite (5–10 g) and thorium concentrates (5–100 g), obtained from thorium plant stream on Dowex 1X8 in acid medium. Gamma-spectrometry, a powerful determination technique, has been used for quantitative determination of protactinium and uranium. Various parameters like sample preparation, optimization of the resin and sample size for 231Pa recovery, 231Pa/235U ratio have been studied in detail and are discussed.

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Abstract

The solid–liquid phase equilibrium data of two binary organic systems, namely, urea (U)–3-aminophenol (AP) and 3-hydroxybenzaldehyde (HB)–β-napthaol (BN) show formation of a eutectic in each case. The enthalpies of fusion of the pure components and binary eutectics have been determined using differential scanning calorimeter (Mettler DSC-4000) system. The thermal properties of the materials such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were computed using the enthalpy of fusion values. The microstructures of eutectics were developed using unidirectional thermal gradient and interested region were photographed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
N. Khare
,
P. Govil
,
Pankaj Kumar
,
A. Mazumder
,
S. Chopra
,
J. Pattanaik
,
S. Balakrishnan
, and
G. Roonwal

Abstract  

The variations in the concentration of 10Be in the core (SK 200/23) from south western Indian Ocean apparently illuminate past levels of 10Be. The level in the core where lower concentration of 10Be (1.01 × 109 atoms/g) is encountered during the Late Holocene is not at tandem with the Late Holocene southern hemisphere temperature variation. The results further suggest that during last glacial maxima (LGM) the 10Be concentration is higher (2.67 × 109 atoms/g) than the Late Holocene values. The present results, though preliminary, show that local bottom topography seems to have influenced the 10Be concentration at core site. Many studies from different geographic regions need to be undertaken before we finally consider 10Be as yet another strong proxy for palaeoclimatic reconstructions.

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Thermal stability and crystallization kinetics of Se–Te–Sn alloys using differential scanning calorimetry

DSC study of Se92Te8−x Sn x (x = 0, 1, 2, 3, 4, 5) chalcogenide glasses

Journal of Thermal Analysis and Calorimetry
Authors:
Rajneesh Kumar
,
Pankaj Sharma
,
P. B. Barman
,
Vineet Sharma
,
S. C. Katyal
, and
V. S. Rangra

Abstract

The present article deals with the differential scanning calorimetric (DSC) study of Se–Te glasses containing Sn. DSC runs are taken at four different heating rates (10, 15, 20 and 25 K min−1). The crystallization data are examined in terms of modified Kissinger, Matusita equations, Mahadevan method and Augis and Bennett approximation for the non-isothermal crystallization. The activation energy for crystallization (E c) is evaluated from the data obtained at different heating rates. Activation energy of glass transition is calculated by Kissinger's relation and Moynihan theory. The glass forming tendency is also calculated for each composition. The glass transition temperature and peak crystallization temperature increases with the increase in Sn % as well as with the heating rate.

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