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Abstract  

A simple, non-destructive and rapid radiochemical separation of radiogallium from Zn and Cu targets by ion-exchange chromatography using Amberlyst 21b was studied. The separation yield was high, while the chemical impurity in the separated radiogallium (inactive Zn or Cu) was low (<0.4 μg). The final product was obtained in the form of gallium citrate in a single step method technique that avoided the time consumption and corrosive evaporation.

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Abstract  

Batch equilibrium measurements were conducted at 25±2 °C with a granular resorcinol-formaldehyde (RF) resin to determine the distribution coefficients (K d) for cesium. In the tests, Hanford Site actual waste sample containing radioactive cesium (137Cs) and a pretreated waste sample that was spiked with non-radioactive 133Cs were used. Initial concentrations of non-radioactive cesium in the waste sample were varied to generate an equilibrium isotherm for cesium. Majority of the tests were conducted at 25±2 °C using a liquid to solid phase ratio of 100 ml/g and at a contact time of 72 hours. Two additional tests were conducted at a liquid to solid phase ratio of 10 and at contact time of 120 hours. The measured distribution coefficient (K d) for radioactive cesium (137Cs) was 948 ml/g, the K dfor non-radioactive cesium (133Cs) was 1039 ml/g. The K dfor nonradioactive cesium decreased from 1039 to 691 ml/g with increased initial cesium concentration from 8 to 64 g/ml. Very little change of the K dwas observed at initial cesium concentration above 64 g/ml. The maximum sorption capacity for cesium on granular RF resin was 1.17 mmole/g dry resin. This value was calculated from the fit of the equilibrium isotherm data to the Dubinin-Radushkevich equation. Previously, a total capacity of 2.84 mmole/g was calculated by Bibler and Wallace for air-dried RF resin.

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Abstract  

A Cd-shield (cylindrical shell 1 mm in thickness, 34 mm in diameter and 180 mm in length) was used to design a permanent epithermal neutron irradiation site for epithermal neutron activation analysis (ENAA) in the Syrian Miniature Neutron Source Reactor (MNSR). This site was achieved by shielding the surface of the aluminum tube of one of the outer irradiation sites. The calculated depression ratio of thermal neutron flux was 1/10. Homogeneity of the neutron flux in the first outer irradiation site has been found numerically using the WIMSD4 and CITATION codes and experimentally by irradiating five short copper wires using the outer irradiation capsule. Good agreement was obtained between the calculated and the measured results of the neutron flux distributions.

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Abstract  

The radiochemical separation of 88Y from proton irradiated natSrCO3 and alpha-particle irradiated natRbCl, of 86Y from proton irradiated 86SrCO3, and of 87Y from alpha-particle irradiated natRbCl were studied at no-carrier-added levels by two techniques, namely, ion-exchange chromatography using Dowex 50W-X8 and Dowex 21K resins, and solvent extraction using HDEHP. Out of all those methods, the ion-exchange chromatography using Dowex 50W-X8 (cation-exchanger) was found to be the best: the separation yield was high, the chemical impurity in the separated radioyttrium (inactive Sr or Rb) was low (0.5 μg) and the final product was obtained in the form of citrate. The optimized separation method using Dowex 50W-X8 was applied in practical production of 86Y and 88Y via proton irradiations of 86SrCO3 and natSrCO3, respectively, at 16 MeV as well as of 87Y and 88Y via α-particle irradiation of natRbCl at 26 MeV. The tangible experimental yields of 86Y and 87Y amounted to 150 and 5.7 MBq/μA·h, respectively. The yields of 88Y obtained were 0.06 MBq/μA·h and 1 MBq/μA·h for alpha-particle and proton irradiations, respectively. Each yield value corresponds to more than 70% of the respective theoretical value.

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Summary  

The removal of cesium from aqueous waste solution was investigated in a column setup using a relatively coarse SuperLigÒ644 resin. The bed volume (BV=140) at the onset of breakthrough surpassed the design requirement of 100 BV at 50% breakthrough, and also corresponds to 99.96% cesium removal. Cesium elution with 0.5M HNO3was satisfactory with a peak BV of 2.5. The elution BV for C/C 0=0.01 was 10, which is less than the target of 15 BV. The percent of sorbed cesium eluted was 99.88%. Further, the BV of the various solutions used for the supporting process steps was sufficient.

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Abstract  

The electrical conductivities of pure and doped manganese(II) carbonate with 10 mol% Li+ or Al3+ ions were measured. The effect of doping on the observed kinetic parameters of decomposition were measured. Doping with Li+ or Al3+ ions enhances the decomposition. The enhanced promotion effect is ascribed to the generation of hole defects which are concentrated at the reaction interface.

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Thermal decomposition of pure basic zinc carbonate (BZC) and doped or mixed with iron ions were studied using TG, DTA and kinetics of isothermal decomposition. The TG and DTA investigations revealed that, the presence of iron ions retards the decomposition processes of (BZC). Also, the retardation effect increases on increasing of iron concentration up to 50 at.%. The curves of isothermal decomposition show the usual sigmoidal character. The decomposition velocity contsant (K) values are plotted vs. 1/T according to Arrhenius equation gave a plot of good straight lines with activation energies of 43.7, 48.2, 53.2 and 57.1 kJ mol−1 for pure (BZC) and incorporated with 1, 10, 30 and 50 at.% Fe2+ respectively. The products of the thermal decomposition of pure BZC and mixed with iron ions are characterized using X-ray diffraction, IR spectroscopy, surface area determination and the surface porosity. These investigations showed that iron ions are effectively incorporated into zinc oxide lattice in the range of 30–50 at.%, which gave a ZnFe2O4 spinel.

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Journal of Thermal Analysis and Calorimetry
Authors: A. A. Said, K. M. Abd El-Salaam, E. A. Hassan, A. M. El-Awad, and M. M. Mohamed

Thermal decomposition of pure Fe(OH)3 and mixed with Co(OH)2 were studied using TG, DTA, kinetics of isothermal decomposition and electrical conductivity measurements. The thermal products were characterized by X-ray diffraction and IR spectroscopy. The TG and DTA analysis revealed the presence of Co2+ retards the decomposition of ferric hydroxide and the formation of α-Fe2O3. The kinetics of decomposition showed that the mixed samples need higher energy to achieve thermolysis. The investigation of thermal products of mixed samples indicated the formation of cobalt ferrite on addition ofx=1 or 1.5 cobalt hydroxide. The electrical conductivity accompanying the thermal decomposition decreases in presence of low ratio of Co2+ (x=0.2) via the consumption of holes created during thermal analysis. The continuous increase in σ values on increasing of Co2+ concentration corresponded to the electron hopping between Fe2+ and Co3+.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. N. Al-Arifi, K. M. Alkarfy, S. A. Al-Suwayeh, K. A. Aleissa, E. I. Shabana, A. A. Al-Dhuwaili, and M. I. Al-Hassan

Summary  

The activity concentration of 210Po was investigated in blood, urine and hair samples of some non-smokers, cigarette-smokers (tobacco-smokers) and shisha smokers (jurak- and mehassel-smokers). The results indicated that 210Po concentration was variable within each group of volunteers and fluctuated within certain range. The activity concentration in the blood of the non-smokers, the cigarette-smokers and the shisha-smokers was found to be ranged from 7-77, 17-86 and 22-92 mBq/l, respectively. These values were ranged from 1.5-10, 3.3-15.9 and 2.2-19.6 mBq/l in the urine samples of the same volunteers, respectively. The 210Po activity concentration in their hair was found to be ranged from 1.9-4.8, 1.9-6.4 and 2-6.5 Bq/kg, respectively. The obtained results are discussed and some conclusions, based upon the average values, were drawn.

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Acta Chromatographica
Authors: Omar M. Khalaf, Mosad A. Ghareeb, Amal M. Saad, Hassan M. F. Madkour, Ahmed K. El-Ziaty, and Mohamed S. Abdel-Aziz

Different solvent extracts of the aerial parts of Senna italica (Mill.) were investigated for their chemical constituents and biological activities. Moreover, bio-guided fractionation led to isolation and identification of six compounds, namely: physcion (1), emodin (2), 2-methoxy-emodin-6-O-β-d-glucopyranoside (3), 1-hydroxy-2-acetyl-3-methyl-6-hydroxy-8-methoxynaphthalene (tinnevellin) (4), quercetin 3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (rutin) (5), and 1,6,8-trihydroxy-3-methoxy-9,10-dioxo-9,10-dihydroanthracene (6). The chemical structures of these compounds were established via 1D and 2D 1H- and 13C-NMR spectroscopy. Ethyl acetate and n-butanol extracts as well as compound 3 were evaluated for their anticancer activity against tumor cell lines. The tested extracts showed a moderate to weak activity, while compound 3 showed a moderate activity against human liver cancer (Hep G2) and breast cancer (MCF-7) cell lines with IC50 values of 57.5 and 42.3 μg/mL, respectively. Both ethyl acetate and n-butanol extracts exhibited antimicrobial activities with different strengths, i.e., ethyl acetate exhibited antimicrobial activity against seven test microbes while n-butanol extract showed antimicrobial activity against all tested microbes. This is the first report for the isolation of compound 3 as a new compound from S. italica growing in Egypt.

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