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Theoretical Assessment of Control Element Assembly Drop Time During SCRAM of APR1400 Reactor
Fahmi Alfa Muslimu,Ihn NAMGUNG 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
The reactor scram is a sudden shutdown of a nuclear reactor by rapid insertion of the Control Element Assembly (CEA) rods into the reactor core in order to stop the fission reaction. The CEA rods drop to the reactor core within the guide tubes by the gravity. For APR 1400, the CEA drop time is less than 4 seconds to meet the reactor physical requirement of emergency reactor shut-down condition in order to prevent run-away fission reaction in the core. The aim of this study is to investigate theoretical minimum mass for the control rod that can make it fully inserted into the guide tube within the required time without failure. The control rod drop time computed using simulation and compared with available data from operational results of APR1400. The 2D axisymmetric model was constructed to simulate the drop motion using dynamic mesh layering technique in Computational Fluid Dynamic (CFD) ANSYS Fluent 19.1. Design parameter such as control rod geometry, guide tube geometry, operating pressure, and core average velocity was adopted from APR1400 and used for simulation. The simulation has shown that when the control rod mass is less than 10.32 kg under the same design geometry it cannot be fully inserted to the guide tube. The 12 finger full strength has been established to drop slower than 4 finger full strength and 4 finger part strength.
Recent Advances in Filter Topologies and Realizations for Satellite Communications
Fahmi, Mohamed M.,Ruiz-Cruz, Jorge A.,Mansour, Rafaat R.,Zaki, Kawthar A. The Korea Institute of Information and Commucation 2011 Journal of communications and networks Vol.13 No.6
This paper presents an overview of recent advances in radio frequency and microwave filter topologies for satellite communication systems. Many types of filters have been developed during the last years in order to satisfy the demands of modern applications in both terrestrial systems and onboard spacecrafts, leading to a great variety of aspects such as transfer functions, resonator implementations or coupling structures. This paper revisits some of the last advances in this area, including the modeling and full-wave simulation. Some recent designs using dual-mode cavities along with other novel implementations in ridge waveguide will be shown.
Fahmi Firdaus Angkasa(파미 피르다우스 앙카사),Ba Hau Vu(부바하우),Rehman Zafar(레흐만 자파르),Il-Yop Chung(정일엽) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10
This paper discusses a novel dispatch strategy for hybrid distributed energy resources (DER) in a stand-alone microgrid design to improve generation efficiency against weather changes. The proposed DER dispatch strategy utilizes day-ahead forecasting of solar irradiance to determine the battery state of charge operation. Compared to conventional dispatch strategies, the proposed approach optimizes battery operation to avoid upcoming inefficient low-loading condition of diesel generators caused by photovoltaic generation intermittency on cloudy days. Furthermore, MATLAB Link in HOMER Pro software is used to build the proposed dispatch strategy. The simulation model is implemented for a stand-alone microgrid in Guanaja Island, Honduras.
Fahmi Shibli,Ofer Z Fass,Oscar Matsubara Teramoto,José M Remes-Troche,Vikram Rangan,Michael Kurin,Ronnie Fass 대한소화기 기능성질환∙운동학회 2023 Journal of Neurogastroenterology and Motility (JNM Vol.29 No.1
Background/AimsPresently, there is paucity of information about clinical predictors, especially esophageal motor abnormalities, for long segment Barrett’s esophagus (LSBE) as compared with short segment Barrett’s esophagus (SSBE). The aims of this study are to compare the frequency of esophageal function abnormalities between patients with LSBE and those with SSBE and to determine their clinical predictors. MethodsThis was a multicenter cohort study that included all patients with a diagnosis of BE who underwent high-resolution esophageal manometry. Motility disorders were categorized as hypercontractile disorders or hypocontractile disorders and their frequency was compared between patients with LSBE and those with SSBE. Multivariable logistic regression modeling was used to calculate the odds of being diagnosed with LSBE relative to SSBE for demographics, comorbidities, medication use, endoscopic findings, and the type of motility disorders. ResultsA total of 148 patients with BE were identified, of which 89 (60.1%) had SSBE and 59 (39.9%) LSBE. Patients with LSBE had a significantly larger hiatal hernia and higher likelihood of erosive esophagitis than patients with SSBE (P = 0.002). Patients with LSBE had a significantly lower mean LES resting pressure, distal contractile integral, distal latency, and significantly higher failed swallows and hypocontractile motility disorders than those with SSBE (P < 0.05). Hiatal hernia and hypocontractile motility disorder increased the odds of LSBE by 38.0% and 242.0%, as opposed to SSBE. ConclusionsThe presence of a hypocontractile motility disorder increased the risk for LSBE. Furthermore, the risk for LSBE was directly associated with the length of the hiatal hernia.
Fahmy, A.M.,Abdelslam, Ahmed K.,Lotfy, Ahmed A.,Hamad, Mostafa,Kotb, Abdelsamee The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2
Recently evolved power electronics' based domestic/residential appliances have begun to behave as single phase non-linear loads. Performing as voltage/current harmonic sources, those loads when connected to a three phase distribution network contaminate the line current with harmonics in addition to creating a neutral wire current increase. In this paper, an enhanced performance three phase four leg shunt active power filter (SAPF) controller is presented as a solution for this problem. The presented control strategy incorporates a hybrid predictive fuzzy-logic based technique. The predictive part is responsible for the SAPF compensating current generation while the DC-link voltage control is performed by a fuzzy logic technique. Simulations at various loading conditions are carried out to validate the effectiveness of the proposed technique. In addition, an experimental test rig is implemented for practical validation of the of the enhanced performance of the proposed technique.
Fahmy, H.H.,Soliman, G.A. The Pharmaceutical Society of Korea 2001 Archives of Pharmacal Research Vol.24 No.3
A new series of pyridazine, pyrazoles, pyrazolidine-3,5-dione, Semicarbazide, thiosemicarbazides, hydantoin, thiohydantoins, 1,2,4-triazoles, S-triazolo[3,4-b]-1,3,4-thiadiazoles incorporated indirectly into salicylamide moiety at position 2 were synthesized. Also the synthesis of novel series of 3-salicylamido-2-hydroxypropyl-amino derivatives were prepared. Several of these compounds were screened for antiinflammatory, analgesic, antipyretic and ulcerogenic activities.
( Fahmy T Ali ),( Mohamed A M Ali ),( Mayada M A Elgizawy ),( Ahmed M Elsawy ) 대한소화기학회 2015 Gut and Liver Vol.9 No.4
Background/Aims: The T-helper 1 (TH1) immune reaction is essential for the eradication of hepatitis C virus (HCV) during pegylated interferon α (PEG-IFN-α)- and ribavirin (RBV)-based therapy in chronic HCV patients. Secreted phosphoprotein 1 (SPP1) was shown to be a crucial cytokine for the initiation of a TH1 immune response. We aimed to investigate whether SPP1 single nucleotide polymorphisms (SNPs) may influence sustained virological response (SVR) rates. Methods: Two SNPs in the promoter region of SPP1 at the .443 C>T and .1748 G>A loci were genotyped in 100 patients with chronic HCV genotype 4 infection using a TaqMan SNP genotyping assay. Results: Sixty-seven patients achieved a SVR, and 33 patients showed no SVR. Patients carrying the T/T genotype at the .443 locus showed a significantly higher SVR rate than those carrying the C/T or C/C genotype (83.67% vs 50.98%, p<0.001). At the .1748 locus, the SVR rate was significantly higher in patients with the G/G genotype than in those with the A/A genotype (88.89% vs 52.63%, p=0.028) and in patients with the G/A genotype than in those with the A/A genotype (85.29% vs 52.63%, p=0.001). Conclusions: SPP1 SNPs at .443 C>T and .1748 G>A loci may be useful markers for predicting the response to PEG-IFN-α-2b plus RBV therapy in Egyptian patients with chronic HCV genotype 4 infection. (Gut Liver 2015;9:516-524)
Fahmy Yasmine A.,Mourad Hebat-Allah M.,Al-Hussaini Emad K. The Korea Institute of Information and Commucation 2006 Journal of communications and networks Vol.8 No.3
In this paper, a generalized blind adaptive algorithm is introduced for multi-user detection of direct sequence code division multiple access (OS-COMA) wireless communication systems. The main property of the proposed algorithm is its ability to resolve the multipath fading channel resulting in inter symbol interference (ISI) as well as multiple access interference (MAI). Other remarkable properties are its low complexity and mitigation to the near-far problem as well as its insensitivity to asynchronous transmission. The proposed system is based on the minimization of the output energy and convergence to the minimum mean square error (MMSE) detector. It is blind in the sense that it needs no knowledge of the other users' signatures, only the intended user signature and timing are required. Furthermore, the convergence of the minimum output energy (MOE) detector to the MMSE detector is analytically proven in case of M-ary PSK. Depicted results show that the performance of the generalized system dominates those previously considered. Further improvements are obtained when multiple input multiple output (MIMO) technique is employed.
Synthesis and Preliminary Antimicrobial Screening of New Benzimidazole Heterocycle
Fahmy, H.H.,El-masry, A.,Ali Abdelsahed, S.H. The Pharmaceutical Society of Korea 2001 Archives of Pharmacal Research Vol.24 No.1
A series of 2-methylbenzimidazole incorporated to different heterocycles through ethyl or carbamoylethyl groups at position 1 of benzimidazole were synthesized. Also 3-(2-methylbenzimidazol-1-yl)propanoic acid hydrazide incorporated with semicarbazides and thiosemicarbazides were prepared. Moreover, the triazole 5e underwent Michael addition and alkylation reaction. Some of the newly synthesized compounds showed considerable antimicrobial activity against gram positive, negative bacteria and yeast.