Hassan A.S.,Minia University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010
In this Letter a conventional method of statistical physics and quantum mechanics is used to calculate the effective area and the expansion energy for trapped Bose gas in a combined optical-magnetic potential. Correction due to the finite number of particles, interatomic interaction and the deepness of the lattice potential are given simultaneously. It is found that the system possess two different phases which are superfluid phase and Mott insulator phase. The critical temperature which separate these two phases is calculated. In the superfluid phase both the effective area and expansion energy is sensitive to the variation of temperature and lattice depth. Mott insulator phase is characterized by vanishing of the condensed fraction and freezing of the effective area at the value which corresponding to BEC transition temperature. So these parameters can serve as a practical thermometer for such system. The expansion energy shows that the lack of expansion in any direction is due to the strong anisotropy of the trapping potential in this direction. The obtained results provide a solid theoretical foundation for the current experiments. © 2010 Elsevier B.V. All rights reserved.
Farahat E.S.,Minia University
Lithos | Year: 2010
Ophiolites are widely distributed in the Central Eastern Desert (CED) of Egypt, occurring as clusters in the northern (NCEDO) and southern (SCEDO) segments. Mineralogical and geochemical data on the volcanic sections of Wizer (WZO) and Abu Meriewa (AMO) ophiolites as representatives of the NCEDO and SCEDO, respectively, are presented.The WZO volcanic sequence comprises massive metavolcanics of MORB-like compositions intruded by minor boninitic dykes and thrust over island-arc metavolcanic blocks in the mélange matrix. Such transitional MORB-IAT-boninitic magmatic affinities for the WZO metavolcanics suggest that they most likely formed in a protoarc-forearc setting. Chemical compositions of primary clinopyroxene and Cr-spinel relicts from the WZO volcanic section further confirm this interpretation. The compositional variability in the WZO volcanic sequence is comparable with the associated mantle rocks that vary from slightly depleted harzburgites to highly depleted harzburgites containing small dunite bodies, which are residues after MORB, IAT and boninite melt formation, respectively. Source characteristics of the different lava groups from the WZO indicate generation via partial melting of a MORB source which was progressively depleted by melt extraction and variably enriched by subduction zone fluids. MORB-like magma may have been derived from ~ 20% partial melting of an undepleted lherzolite source, leaving slightly depleted harzburgite as a residuum. The generation of island-arc magma can be accounted for by partial melting (~ 15%) of the latter harzburgitic mantle source, whereas boninites may have been derived from partial melting (~ 20%) of a more refractory mantle source previously depleted by melt extraction of MORB and IAT melts, leaving ultra-refractory dunite bodies as residuum.The AMO volcanic unit occurs as highly deformed pillowed metavolcanic rocks in a mélange matrix. They can be categorized geochemically into LREE-depleted (La/YbCN=0.41-0.50) and LREE-enriched (La/YbCN=4.7-4.9) lava types that show an island arc to MORB geochemical signature, respectively, signifying a back-arc basin setting. This is consistent, as well, with their mantle section. Source characteristics indicate depleted to slightly enriched mantle sources with overall slight subduction zone geochemical affinities as compared to the WZO.Generally, CED ophiolites show supra-subduction zone geochemical signature with prevalent island arc tholeiitic and minor boninitic affinities in the NCEDO and MORB/island-arc association in the SCEDO. Such differences in geochemical characteristics of the NCEDO and SCEDO, along with the abundance of mature island arc metavolcanics which are close in age (~ 750. Ma) to the ophiolitic rocks, general enrichment in HFSE of ophiolites from north to south, and lack of a crustal break and major shear zones, is best explained by a geotectonic model whereby the CED represents an arc-back-arc system above a southeast-dipping subduction zone. © 2010 Elsevier B.V.
Balboul B.A.A.,Minia University
Journal of Analytical and Applied Pyrolysis | Year: 2010
The decomposition course, intermediates and final products of praseodymium acetate monohydrate Pr(CH3COO)3·H2O in different gas atmospheres (O2, N2 or H2) were characterized using thermal analysis, X-ray diffractometry and infrared spectroscopy. Praseodymium acetate decomposes in five mass loss events leading to the formation of the intermediate products Pr(OH)(CH3COO) 2, PrO(CH3COO) and Pr2O2CO 3. Results obtained indicate that praseodymium acetate decomposes into a number of intermediate products whose chemical structure is independent on the gas atmosphere applied, but the kinetics of their formation and subsequent decomposition is considerably enhanced in O2 atmosphere. The final product at 700 °C was found to be praseodymium oxide Pr 6O11 in O2 and N2, but mixed with minority Pr2O3 in H2 atmosphere. Surface texture and 2-propanol decomposition activity of the final products at 700 °C were determined by means of N2 sorptiometry and in situ IR spectroscopy. The final products in O2 and N2 were slightly more active catalysts toward 2-propanol decomposition the latter was of higher selectivity toward the alcohol dehydration, which is suggested to be correlated with the evolution of a narrower mesoporous structure on its surface. © 2010 Elsevier B.V. All rights reserved.
Hussein A.,Minia University
Fertility and Sterility | Year: 2013
Objective: To evaluate the use of a diagnostic testis biopsy and a repetition of testicular sperm extraction (TESE) surgeries in azoospermic patients and its impact on the outcome of TESE. Design: Retrospective, case-control study. Setting: University IVF center and hospital. Patient(s): A total of 552 azoospermic patients undergoing TESE for intracytoplasmic injection. Intervention(s): At the time of the TESE, a piece of testicular tissue was prepared for histopathologic evaluation. Main Outcome Measure(s): Sperm retrieval rate. Result(s): Testicular sperm retrieval was successful in 100% of patients with obstructive azoospermia, 95.6% of patients with hypospermatogenesis, 47.9% of patients with maturation arrest, and 28.6% of patients with Sertoli cell-only syndrome in cases with no previous testicular surgery; in 100%, 91.4%, 32%, and 13.3%, respectively, in cases with a history of one testicular surgery; and in 100%, 10%, 0, and 0, respectively, in cases with a history of two testicular surgeries. Conclusion(s): Testicular sperm retrieval may be successful for some patients in each histopathologic category of azoospermia, with variable degrees of success for different histopathologic categories. The repetition of testicular surgeries decreases the chance of finding sperm in subsequent testicular sperm retrieval procedures. Copyright © 2013 Published by Elsevier Inc.
Breisha G.Z.,Minia University
Biomass and Bioenergy | Year: 2010
A strain of Saccharomyces cerevisiae, which showed marked fermentation activity, ethanol and temperature tolerance and good flocculation ability, was selected for ethanol production. A stuck fermentation occurred at sucrose concentration of 25%. Increasing the yeast inoculum volume from 3% to 6% showed positive effects on fermentation from 25% sucrose. The ratio of added nitrogen to sucrose, which gave the best results (for the selected yeast strain), was determined. It was concluded that this ratio (nitrogen as ammonium sulphate at a rate of 5mgg-1 of consumed sucrose) is constant at various sugar concentrations. Addition of nitrogen at this ratio produced 11.55% ethanol with complete consumption of 25% sucrose after 48h of fermentation. However fermentation of 30% sucrose at the above optimum conditions was not complete. Addition of yeast extract at a level of 6gl-1 together with thiamine at a level of 0.2gl-1 led to complete utilization of 30% sucrose with resultant 14% ethanol production. However the selected yeast strain was not able to ferment 35% sucrose at the same optimum conditions. Addition of air at a rate of 150dm3min-1m3 of reactor volume during the first 12h of fermentation led to complete consumption of 35% sucrose and 16% ethanol was produced. This was approximately the theoretical maximum for ethanol production. © 2010 Elsevier Ltd.