Search Results

You are looking at 1 - 10 of 15 items for

  • Author or Editor: K. Hassan x
  • All content x
Clear All Modify Search

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.

Restricted access

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.

Restricted access

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.

Restricted access

Acinetobacter baumannii is an opportunistic pathogen that is reported as a major cause of nosocomial infections. The aim of this study was to investigate the biofilm formation by A. baumannii clinical and soil isolates, to display their susceptibility to 11 antibiotics and to study a possible relationship between formation of biofilm and multidrug resistance. During 8 months period, from June 2016 to January 2017, a total of 52 clinical and 22 soil isolates of A. baumannii were collected and identified through conventional phenotypic, chromo agar, biochemical tests, API 20E system, and confirmed genotypically by PCR for blaOXA-51-like gene. Antibiotic susceptibility of isolates was determined by standard disk diffusion method according to Clinical and Laboratory Standard Institute. The biofilm formation was studied using Congo red agar, test tube, and microtiter plate methods. The clinical isolates were 100% resistance to ciprofloxacin, ceftazidime, piperacillin, 96.15% to gentamicin, 96.15% to imipenem, 92.31% to meropenem, and 78.85% to amikacin. The soil A. baumannii isolates were 100% sensitive to imipenem, meropenem, and gentamicin, and 90.1% to ciprofloxacin. All A. baumannii isolates (clinical and soil) were susceptible to polymyxin B. The percentage of biofilm formation in Congo red agar, test tube, and microtiter plate assays was 10.81%, 63.51%, and 86.48%, respectively. More robust biofilm former population was mainly among non-MDR isolates. Isolates with a higher level of resistance tended to form weaker biofilms. The soil isolates exhibited less resistance to antibiotics than clinical isolates. However, the soil isolates produce stronger biofilms than clinical isolates.

Restricted access

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.

Restricted access

The space available to plants affects the available resources and hence modifies the growth habits and yield potential of plants. The effect of four seeding densities (250, 500, 750 and 1000 viable seeds/m2) and three row spacings (12, 15 and 20 cm) were evaluated at Morfa Mawr field station at the University of Wales, Aberystwyth, UK during the 1993 and 1994 growing seasons. Number of capsules per plant, number of seeds per capsule, thousand-seed weight and seed yield were examined during the study. Capsule index (CI) and harvest index (HI) were calculated from the observed data. During the first year, capsules per plant, seeds per capsule and capsule index were increased by decreasing the seed density, while the maximum seed yield of 3.9 t/ha was recorded at the highest seed density of 1000 seeds/m2. An increase in row spacing led to an almost linear increase in most of the yield attributes of the crop. During the second year, the response of yield and yield attributes to seeding densities was similar to that recorded during the first year. Seed yield increased with decreasing row spacing, while the rest of the components did not show any consistent response. During the first year, the overall performance and production of the crop was higher than in the second year because of the better weather conditions, with mild temperature and high rainfall during the season.

Restricted access

Abstract  

A bibliometric analysis of agricultural literature published in Malaysia between 1981–1990 was undertaken. The analysis shed light on the key journals that published agricultural literature; on the forms of publications which are resorted to in the communication of research results; on the subject areas which are well written on and those that have been neglected; on the nature of contributions made by Malaysian authors; on the publishing practice of corporate bodies and on the number of publications produced each year.

Restricted access

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.

Restricted access

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.

Restricted access

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.

Restricted access