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RISS 인기검색어
- 검색키워드
- 저자 : Abdelrazek, Fathy-M. (검색결과 14 건)
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Structural, optical, thermal and electrical studies on PVA/PVP blends filled with lithium bromide
E.M. Abdelrazek,I.S. Elashmawi,A. El-khodary,A. Yassin 한국물리학회 2010 Current Applied Physics Vol.10 No.2
Films of PVA/PVP blend (50/50) filled with different concentrations of LiBr were prepared. The prepared films were investigated by different techniques. XRD scans demonstrate that complexation between the filler and the blend takes place in the amorphous region. UV–VIS analysis revealed that the values of the optical energies are changed with increase Li-ions content. This indicates that there is a charge transfer complexes arise between the polymer blend and Li-ions. The thermal stability of the product samples has improved after filling LiBr increases, this indicates that the filler acts as a plasticizer. The rise of the conductivity is significant with increased concentration of LiBr, this is means the decrease in the degree of crystallinity and increase in the degree of amorphosity. This suggests the choice of LiBr as filler to improve the electrical conductivity of PVA/PVP.
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Khalil, Khalil Abdelrazek,Kim, Sug Won,Dharmaraj, N.,Kim, Kwan Woo,Kim, Hak Yong Elsevier 2007 Journal of materials processing technology Vol. No.
<P><B>Abstract</B></P><P>Novel technique was introduced to improve fracture toughness of hydroxyapatite (HAp) bioceramics. Composites of HAp/NiO with 1–5wt% of electrospun NiO nanofibers were synthesized by wet-milling technique and the mixtures were consolidated rapidly to full density by high-frequency induction heat sintering (HFIHS). Effect of electrospun NiO nanofibers content on the toughness, hardness and microstructure properties was studied. The resulting composites showed good sintering behaviors, high toughness and hardness. Compared with the toughness of pure HAp, the heat sintered HAp/NiO nanofiber composites showed 200% increase in the toughness by the addition of 5wt% NiO nanofibers. This can be related to the homogeneous dispersion of NiO nanoparticles in HAp at nanometer scales.</P>
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Effect of Berm Properties on Non-Cohesive Earth Dam Failure due to Overtopping
Shaimaa Aman,Mohamed Abdelrazek Rezk,Rabiea Nasr 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5
Berms are typically built on the upstream and downstream slopes of earth dams to provide slope stability against seepage. The influence of berm properties on dam stability is widely studied in much research. The most important thing during dam failure by overtopping is to delay its failure and reduce maximum outflow discharge to give the region downstream chance to evacuate. In this paper, the effect of cutting berm with varying widths and heights on the erosion process, delaying the dam failure and reducing maximum outflow discharge during an overtopping event is experimentally investigated. The mean goal is to find the optimum berm width and height which give the best results of time of dam failure and maximum outflow discharge. To fulfill this goal many experiments are conducted and for each one, the erosion process, the time of dam failure, maximum outflow discharge and its time are measured and analyzed. In addition, two experiments lining the downstream slope are performed. The results revealed that constructing a berm with relative width equal to 0.33 and a relative height equal to 0.5, increases the time of dam failure by 12.5%, decreases the maximum outflow discharge by 2.22%, and increases the time to maximum outflow discharge by 25%. Also, it is found that the relative berm height ranges from 0.5 to 0.67 gives the optimum results. However, it is found that lining the upper part of the downstream slope and crest improves the results for relative berm heights less than 0.5. Lining significantly increases the time of dam failure by four times more than the case without lining and greatly delays the occurrence of maximum outflow discharge.
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Negm, Abdalla-M.,Abdelrazek, Fathy-M.,Elnagdi, Mohamed-H.,Shaaban, Lina-H. The Pharmaceutical Society of Korea 1994 Archives of Pharmacal Research Vol.17 No.6
Phenylazocyanothioacetamide 1 reacts with malononitrile to afford the pyridinethione 4 which reacts with phenacylbromide to yield the pyridine-S-phenacyl derivative 6, 1 reacts with ethyl cyanoacetate to yield the pyridazine derivative, 8, and with phenacyl bromide to afford the N-phenacyl derivative 11, instead of the thiazole 10. Compound 11 afforded the pyrazolopyridine 13 on reaction with malononitrile while 10 was obtained on coupling of the thiazole 14 with diazotised aniline. Compound 10 reacts with malononitrile to afford the thizaolyl pyridazine 15. Compound 1 reacts with malononitrile dimer to afford the pyriodopyridazine derivative 17a. 1 reacts also with active methylene heterocycies to afford the pyrazolo and thiazolo-fused phridazines 20 and 23 respectively.
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Abdelaziz, Mohamed,Anwer, Wael,Abdelrazek, Abeer Hamada Korean Society for Bioinformatics 2010 Interdisciplinary Bio Central (IBC) Vol.2 No.4
Total aflatoxin and ochratoxin were detected in 3 naturally contaminated fish feed samples using immune-affinity method. The results revealed that the average levels of aflatoxins in the 3 examined samples were (15, 22 and $12\;{\mu}g/kg$) respectively while the average levels of ochratoxins were (15, 6 and $6\;{\mu}g/kg$). The results of determination of the effects of clay as a mycotoxin binder on the health status and performance of Oreochromis niloticus in comparing with a control group revealed that the survival rate in control group was 81% after the end of the culture season. The results also revealed that the survival rate in group 2 which received clay treated feed was 86%. The results of regular parasitological examination revealed the identification of trichodina as external protozoa in Oreochromis niloticus from both ponds but without manifestation of disease signs. The results of bacteriological examination revealed the isolation and identification of Pseudomonas flouresence from some moribund Oreochromis niloticus. Higher performance parameters were recorded in group 2 that received feeds treated with clay which reflected in the total production which reaches 1646.47 kg while in the control pond, the total production was1308.36 kg.
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Mohamed, Hend Omar,Obaid, M.,Khalil, Khalil Abdelrazek,Barakat, Nasser A.M. Elsevier 2016 International journal of hydrogen energy Vol.41 No.7
<P><B>Abstract</B></P> <P>The use of commercially available cation and anion exchange membranes to generate power from industrial wastewater obtained from three different industries (food, alcohol and dairy factories) without the addition of external microorganisms or chemicals by using microbial fuel cells (MFCs) was investigated. The results indicate that the original mixed culture of microorganisms presented in wastewater can act as an effective bio-anode. Overall, the tested wastewaters show a good tendency for power generation in both cation- and anion- based MFCs. However, when compared to anion membranes, cation membranes exhibit a distinctly higher performance for all tested wastewaters. Cation membrane-based MFCs generate 1007 mWm<SUP>−3</SUP> of power from food, 627 mWm<SUP>−3</SUP> from alcohol, and 507 mWm<SUP>−3</SUP> from dairy wastewaters while anion membranes generate 190.5, 164, and 38 mWm<SUP>−3</SUP>, respectively. COD analyses and Coulombic efficiency measurements indicate that more organic pollutants are removed and higher efficiency is achieved by using cation membrane-MFCs rather than anion ones. SEM images of the anodes confirmed the formation of active bio-anodes with attached microorganisms, and FT-IR analyses reveal that the anion membranes are slightly affected by the wastewaters, especially by dairy wastewaters while the cation membranes exhibit a comparatively higher stability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Microbial fuel cells can be effectively utilized with industrial wastewaters. </LI> <LI> Cation membranes exhibit distinctly high performance. </LI> <LI> The suggested MFCs are working without using external microorganisms. </LI> <LI> The as-received industrial wastewaters were used without preliminary treatment. </LI> </UL> </P>
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Engy M. Khalil,Farouk A. El-Fitiany,Mohammed A. Abourohiem,Ahmed M. Abdelrazek 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1
For pressurized irrigation networks, the pump station is usually designed to guarantee the required operation head at all hydrants. Such a design usually results in a considerable waste of energy. Significant energy saving may be achieved by using booster pumps at critical hydrants. However, this will increase total capital cost and reduces the net economic benefit. A lot of research work has been carried out to minimize energy consumption, but no comprehensive economic study is available, which includes booster pumps. In the current study, an economic analysis of using a booster pump is carried out. Additional energy savings may be realized by dividing the hydrants into sectors. Four different scenarios are investigated. The proposed methodology is applied to a drip irrigation network at Kostol area, Egypt. The total capital cost increased by about 15.90%. However, this increase can be recovered in about five years through energy saving. Annual energy consumption is reduced by up to 35.6%. It is well understood that these results are constrained by temporal and spatial variations of field data. However, accumulated experience gained by similar studies for different networks and varying costs will provide valuable guidelines for the designers. Research may be extended to include additional operation and maintenance costs, water costs, and crop return value.
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Enhanced Real Coded Genetic Algorithm for Optimal DG Placement in a Radial Distribution System
Almabsout Emad Ali,El-Sehiemy Ragab A.,Bayoumi Ahmed Saeed Abdelrazek 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4
Active and reactive power flows in distribution systems have a significant impact on the efficiency of power distribution systems. The optimal placement of distributed power generation units is the most popular approach for improving power quality, voltage profile and reducing the total power loss of distribution systems. This paper presents an enhanced algorithm to handle the optimal capacity and placement of multi-distributed generation units in radial distribution networks (RDN). In this light, a proposed local search scheme has been integrated into the real coded genetic algorithm by the proposed algorithm to exploit its advantages reduce the search time required for finding the optimal placement and size of DG in RDN. The proposed genetic algorithm evaluates population solutions by minimizing total real power losses in a system and improve the voltage profile. To investigate the performance of the proposed algorithm, two common radial systems have been used, namely, IEEE 33-bus, 69-bus networks. The experimental results demonstrate that the implemented enhanced genetic algorithm can find the best solutions to the problem effectively reducing the power loss and improving the voltage profile and outperform other current literature algorithms. Moreover, the energy losses cost, and total voltage deviation have been investigated. Significant improvement in the power losses and voltage profile enhancement with the increasing of distributed generation units has been reached. The feasibility of the method for practical application has been investigated and validated with preserving the constraints and operational restrictions.
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