Time filter

Source Type

Hebron, Palestine

Hebron University is an independent Palestinian institution of higher education, with over 8,600 students, around 75% of whom are female. Wikipedia.

Aqra F.,Hebron University
Journal of Non-Crystalline Solids | Year: 2014

In the framework of the theoretical considerations suggested by Eyring, based on statistical thermodynamics, calculations of reliable values and accurate estimate of surface tension and surface energy of alkali halides are presented. The ratio of surface energy, at melting temperature, of solid and liquid phases is constant for all the alkali halides and is equal to 1.465. Moreover, empirical relations are proposed for calculating the surface tension, the cohesive energy density and the isothermal compressibility. Finally, a promising theoretical equation is obtained for determining the product of the isothermal compressibility and the surface tension. All the results are in very good agreement with the available experimental data with a difference that does not exceed 7% for most of the salts under study. The results provide a good database useful for scientists and engineers. © 2014 Elsevier B.V. Source

Aqra F.,Hebron University
Journal of Nuclear Materials | Year: 2014

The surface tension of ThF4, UF4 and UF6 is theoretically estimated, as function of temperature, whereas eight other halide salts only for temperature equal to their melting points. Calculations are based on a model, using statistical thermodynamics of Eyring theory. It is observed that the surface tension decreases linearly with temperature. The results are strictly compared with the available experimental data. The technique can be applied for conditions where experimental data are currently missing. The compressibility and surface tension products, of all salts under study, were also calculated. © 2014 Elsevier B.V. All rights reserved. Source

Aqra F.,Hebron University
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2014

This article provides a new model for predicting the surface tension of molten alkali halides, because the subject is worthy of investigation. A relationship exists between the surface tension (γ) at the melting point (T m ), molar volume (V), internuclear distance (D), and radius ratio (r+/r-). The basic idea results from the assumption that all of the parameters are constants. The relation depends on the reliability and accuracy of all the constants on which it is based. The formula was examined and showed remarkable agreement between the calculated surface tension and experimental data within a difference of less than 10 pct for most of the salts studied. © 2014 The Minerals, Metals & Materials Society and ASM International. Source

Thabayneh K.M.,Hebron University
Radiation protection dosimetry | Year: 2013

The activity concentrations of naturally occurring radioactive materials such as (226)Ra, (238)U, (232)Th, (40)K and (137)Cs were measured for 44 plant samples collected from different locations in the northwestern region of the West Bank, Palestine, using high-resolution gamma ray spectroscopy. The activity concentrations of radionuclides in the investigated plant samples ranged from 7.5 to 157.6 Bq kg(-1) for (226)Ra, 7.5 to 66.1 Bq kg(-1) for (238)U, 1.8 to 48.5 Bq kg(-1) for (232)Th, 14.3 to 1622 Bq kg(-1) for (40)K and <0.1 to 4.7 Bq kg(-1) for (137)Cs. The average values of these activities were 48.3, 26.5, 10.1, 288.0 and 2.2 Bq kg(-1), for (226)Ra, (238)U, (232)Th, (40)K and (137)Cs, respectively. The study presents the total gamma radiation dose rate assessed from natural radionuclides,(137)Cs and cosmic radiation, the dose rate of each radionuclide and the effective dose for all the samples. The radiological health implication to the population that may result from these doses is found to be low, except in few cases. The measurements have been taken as representing a baseline database of values of these radionuclides in the plants in the area. Source

Aqra F.,Hebron University
Physica B: Condensed Matter | Year: 2014

The capability of a new model on predicting the surface tension of molten alkali halides is described. A relationship, with a simple form of calculation, exists between the surface tension (γ) at the melting point, molar volume (V), inter-nuclear distance (D) and the enthalpy of sublimation (Es). The basic idea results from the assumption that all the parameters are constants that are usually easy to acquire. Moreover, two previous models (Furth and Schytil equations) were also checked and applied for calculating surface tension of molten salts. The three formulas have been examined for 20 salts and showed remarkable agreement between calculated and experimental data with a difference of less than 10% for most of the salts studied. The heats of sublimation of alkali halides were, theoretically, calculated and compared to literature values. © 2014 Elsevier B.V. Source

Discover hidden collaborations