Synthesis and Reactions of New Thienopyridines, Pyridothienopyrimidines and Pyridothienotriazines

E.A.Bakhite,A.E.Abdel-Rahman,O.S.Mohamed,E.A.Thabet 대한화학회 2002 Bulletin of the Korean Chemical Society Vol.23 No.12

Synthesis and Reactions of New Thienopyridines, Pyridothieniopyrimidines and Pyridothienotriazines

Bakhite, E.A.,Abdel Rahman, A.E.,Mohamed, O.S.,Thabet, E.A. Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.12

4-Aryl-3-cyano-6-(2'-thienyl)-pyridine-2(1H)-thiones(1a-c) were reacted with phenacyl bromide, chloro-N-arylacetanmides or 2-chloroacetylaminopyridine to furnish 2-functionalized 3-amino-4-aryl-6-(2'-thienyl)-thieno[2,3-b]pyridines 4a-c and 5a-c or 5d respecitively. The compounds 5a-d underwent different sequence of reactions to produce a variety of thienylpyridothienopyrimidines and, thienylpyridothienotriazines. Some of the prepared compounds were tested in vitro for their antimicrobial activities.

Analysis of radioactivity levels and hazard assessment of black sand samples from Rashid area, Egypt

Mohamed A.E. Abdel-Rahman,Sayed A. El-Mongy 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.8

The aim of this study is to evaluate the radioactivity levels and radiological impacts of representative black sand samples collected from different locations in the Rashid area, Egypt. These samples were prepared and then analyzed using the high-resolution gamma ray spectroscopy technique with a highpurity germanium detector. The activity concentration (Ac), minimum detectable activity, absorbed gamma dose rate, external hazard index (Hex), annual effective dose rate equivalent, radium equivalent, as well as external and internal hazard index (Hex and Hin, respectively) were estimated based on the measured radionuclide concentration of the 238U(226Ra) and 232Th decay chains and 40K. The activity concentrations of the 238U, 232Th decay series and 40K of these samples varied from 45.11 ± 3.1 Bq/kg to 252.38 ± 34.3 Bq/kg, from 64.65 ± 6.1 Bq/kg to 579.84 ± 53.1 Bq/kg, and from 403.36 ± 20.8 Bq/kg to 527.47 ± 23.1 Bq/kg, respectively. The activity concentration of 232Th in Sample 1 has the highest value compared to the other samples; this value is also higher than the worldwide mean range as reported by UNSCEAR 2000. The total absorbed gamma dose rate and the annual effective dose for these samples were found to vary from 81.19 nGy/h to 497.81 nGy/h and from 99.86 μSv/y to 612.31 μSv/y, which are higher than the world average values of 59 nGy/h and 70 μSv/y, respectively. The Hex values were also calculated to be 3.02, 0.47, 0.63, 0.87, 0.87, 0.51 and 0.91. It was found that the calculated value of Hex for Sample 1 is significantly higher than the international acceptable limit of <1. The results are tabulated, depicted, and discussed within national and international frameworks, levels, and approaches.

Effect of Three Different Species of Hay on Dry-matter Intake and Serum Cortisol of Ewes

Sekine, J.,Abdel-Rahman, Mootaz A.M.,Ismail, A.El-Moez A.,Dosoky, R.M.,Kamel, H.E.M.,Hishinuma, M. Asian Australasian Association of Animal Productio 2003 Animal Bioscience Vol.16 No.9

To determine whether the feeding of different species of hay affects the dry-matter intake and the serum cortisol level of sheep, 6 non-pregnant, non-lactating ewes were offered alfalfa (Medicago sativa) hay (Al), oats (Avena sativa) hay (Ot) and perennial ryegrass (Lolium perenne) hay (Pr) under 6 kinds of treatment including 1) change from Al to Ot, 2) Al to Pr, 3) Ot to Al, 4) Ot to Pr, 5) Pr to Al, and 6) Pr to Ot. The experimental design was a 6${\times}$6 Latin square with a 14 day period of which 9 days were a preliminary period and 5 days as a digestion trial period. The change in hay feeding was done abruptly on the first day of each period without an adaptation period. The blood from the jugular vein was collected on the first, third and the last day of each period through a sterile catheter for the analysis of cortisol. The dry-matter intake was recorded daily throughout the period. The mean daily intake of dry matter (DM, g/kg live weight) was significantly different among the 3 species of hay (Al>Ot>Pr; p<0.05). The digestibility of DM for Al and Ot was the same, but that for Pr was significantly lower than Al and Ot (p<0.05). The mean serum cortisol levels were significantly different among the hays (p<0.05). The level for Pr was the highest and that for Al was the lowest. The abrupt change of hay feeding of 6 treatments produced a significant change in the serum cortisol levels. The DM intake was inversely related to the change of the cortisol level. It is suggested that the animal' intake response to different species of hay may be partly motivated by the psychological feelings toward the hay offered.

On the static stability of nonlocal nanobeams using higher-order beam theories

Eltaher, M.A.,Khater, M.E.,Park, S.,Abdel-Rahman, E.,Yavuz, M. Techno-Press 2016 Advances in nano research Vol.4 No.1

This paper investigates the effects of thermal load and shear force on the buckling of nanobeams. Higher-order shear deformation beam theories are implemented and their predictions of the critical buckling load and post-buckled configurations are compared to those of Euler-Bernoulli and Timoshenko beam theories. The nonlocal Eringen elasticity model is adopted to account a size-dependence at the nano-scale. Analytical closed form solutions for critical buckling loads and post-buckling configurations are derived for proposed beam theories. This would be helpful for those who work in the mechanical analysis of nanobeams especially experimentalists working in the field. Results show that thermal load has a more significant impact on the buckling behavior of simply-supported beams (S-S) than it has on clamped-clamped (C-C) beams. However, the nonlocal effect has more impact on C-C beams that it does on S-S beams. Moreover, it was found that the predictions obtained from Timoshenko beam theory are identical to those obtained using all higher-order shear deformation theories, suggesting that Timoshenko beam theory is sufficient to analyze buckling in nanobeams.

Electric, Thermoelectric and Magnetic Properties of Nickel(II) Imine Nanocomplexes

A. Elshafaie,Laila H. Abdel-Rahman,Ahmed M. Abu-Dief,Samar Kamel Hamdan,A. M. Ahmed,E. M. M. Ibrahim 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.7

Production of novel organic semiconductor nanomaterials is essential for enabling the development of personal, portable and flexible electronic modules. This work presents Ni(II)-Schiff base complexes with enhanced Seebeck coefficient and weak ferromagnetic ordering for thermoelectric and magnetic devices. Four Ni(II)-Schiff base complexes (namely [Ni(C12H10N3O4Br)] · 2H2O, [Ni(C16H11N3O4] · 2H2O, [Ni(C21H14N5O8Br)] and [Ni(C25H17N5O8)] · 1/2H2O) have been synthesized in nanosized dimensions. The electrical and thermoelectric properties have been studied, and comprehensive discussions have been presented to understand the electrical conduction mechanisms. The electrical conductivity measurements reveal that the conduction is due to the charge carriers hoping between the atomic sites of the same energy levels in the molecule as well as the transfer of the charge carriers between the neighboring complex molecules due to overlapping of their orbitals. The thermoelectric measurement confirms that the nanocomplexes (NCs) are non-degenerate P-type semiconductors with enhanced Seebeck coefficient values compared with those reported for other organic materials. The NCs exhibit antiferromagnetic to paramagnetic transitions with the increase of temperature and weak ferromagnetic ordering at 300 K.

Studies on Υ-irradiated polymer–nano calcined clay blended cement mortar composites

M.R. Ismail,E. Hamed,H.A. Abdel-Rahman,M.M. Younes,S.H. El-Hamouly 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

This study focuses on the preparation of blended cement mortars by a partial replacement of Portland cement by different ratios of nano-calcined clay. Also, the addition of PVA on blended cement mortar with different percentages. In addition to the influence of different doses of gamma rays on the physicochemical properties of the blended cement composites; the specimens are cured under tap water. Results showed that, compressive strength and bulk density of the composites increased with increasing the irradiation dose and PVA contents for certain values while, total porosity behaved in an opposite direction. XRD, SEM, TGA confirmed these conclusions.

Searching for the viability of using thorium-based accident-tolerant fuel for VVER-1200

Mohsen Mohamed Y.M.,Abdel-Rahman Mohamed A.E.,Omar Ahmed,Alnassar Nassar,Galahom A. Abdelghafar 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.1

This study explores the feasibility of employing (U, Th)-based accident tolerant fuels (ATFs), specifically (0.8UO2, 0.2ThO2), (0.8UN, 0.2ThN), and (0.8UC, 0.2ThC). The investigation assesses the overall performance of these proposed fuel materials in comparison to the conventional UO2, focusing on deep neutronic and thermal-hydraulic (Th) analyses. Neutronic analysis utilized the MCNPX code, while COMSOL Multiphysics was employed for thermal-hydraulic analysis. The primary objective of this research is to overcome the limitations associated with traditional UO2 fuel by exploring alternative fuel materials that offer advantages in terms of abundance and potential improvements in performance and safety. Given the limited abundance of UO2, long-term sustainable nuclear energy production faces challenges. From a neutronic standpoint, the U–Th based fuels demonstrated remarkable fuel cycle lengths, except (0.8UN, 0.2ThN), which exhibited the minimum fuel cycle length and, consequently, the lowest fuel burn-up. Regarding thermal-hydraulic performance, (0.8UN, 0.2ThN) exhibited outstanding performance with significant margins against fuel melting compared to the other materials. Overall, when considering the integrated performance, the most favourable results were obtained with the use of the (0.8UC, 0.2ThC) fuel configurations. This study contributes valuable insights into the potential benefits of (U, Th)- based ATFs as a promising avenue for enhanced nuclear fuel performance.