Numerical Investigations on Dynamic Performance of Stiffened Box Steel Bridge Piers

Raafat E. S. Ismail,Fahmy A. Fathelbab,Hesham A. Zien Eldin,Sameh I. Zenhom 한국강구조학회 2012 International Journal of Steel Structures Vol.12 No.2

The aim of this paper is to carry out extensive numerical investigations about the effect of various structural parameters on the dynamic performance of stiffened box steel bridge pier under a strong earthquake ground motion. The considered structural parameters are the local slenderness ratios of stiffener and stiffened wall as well as the global slenderness ratio of the pier. In the present study, all investigated piers are made of high tensile steel with high yield ratio. The non-linear time history analyses are carried out using in-house Finite Element Program DYNAPSS, recently developed by the first author. This program is verified by comparing its results with the results obtained by the general FE program. In this program, the geometrical nonlinearity is considered on the bases of Total Lagrangian formulation, while the non-linearity of structural steel material is considered through implementation of modified multisurface cyclic plasticity model by which real characteristics of high tensile steel material such as, Plateau, Massing type of Bauschinger’s effect, disappearing of Plateau and cyclic strain hardening, are accurately modeled. The results are closely examined in respect with the damage index criterion. From this study, it is found that the increase in slenderness ratios of stiffener does not only increase the damage index, but also may lead to the full collapse. Furthermore, the damage index increases with the increase of local slenderness ratio of stiffened wall and the global slenderness ratio. Also, it is found that when the loacal buckling is not the dominant eigen mode and the pier behave as a single degree of freedom, the natural period has destructive effects when it is close to predominant period of the earthquake. Finally, contour plots of damage index values are presented. These contour plots may be greatly useful for the design of stiffened box steel bridge piers, where, critical values of structural parameters corresponding to certain value of damage index could be determined.

Analytical Modeling of Nonlinear Behavior of Composite Stub-Girders

Raafat E. S. Ismail,Mohamed T. H. El-Katt,Hesham A. Zien Eldin,Younis M. Y. Kasem 한국강구조학회 2012 International Journal of Steel Structures Vol.12 No.4

This paper presents an inelastic analytical model for modeling the nonlinear behavior of partially composite stub-girder under midspan concentrated load with partially end joint stiffness. The method treats the stub-girder as a beam with three distinct layers, the top and bottom layers behave according to the normal beam bending theory, while the middle layer is a shear layer without any bending stiffness. At the interface between the steel and concrete elements, the headed stud shear connectors are modeled as linear elastic built-in cantilevers. The present method smears the effects of all the contributing shear elements, stubs and studs, along the span. The differential equation for the stub-girder is solved to obtain the general expression of elastic deflection for the case when one concentrated load is applied at the mid-span. Based on the present approach a computer program called “PZA” is developed. The program accounts for nonlinear behavior of concrete and steel materials. The accuracy and reliability of the program are demonstrated by the analysis of three stub girders and one composite beam over the entire loading range up to ultimate load and the results are compared with published experiments.. A relatively good agreements with the experimental findings are found. Then a parametric study is carried out to discuss the effect of the initial stiffness of shear connector and the stub height on the behavior of stub-girder.

Preparation and efficacy of freeze-dried inactivated vaccine against bovine viral diarrhea virus genotypes 1 and 2, bovine herpes virus type 1.1, bovine parainfluenza-3 virus, and bovine respiratory syncytial virus

Maha Raafat Abd El Fadeel,Ashraf Taha El-Dakhly,Ahmad Mohammad Allam,Tarek Korany Farag,Alaa Abdel-Moneim El-kholy 대한백신학회 2020 Clinical and Experimental Vaccine Research Vol.9 No.2

Purpose: Bovine respiratory disease is a worldwide health concern in the feedlot cattle causing morbidity and mortality in young with major economic losses to the producer. Programs of vaccination are integral parts of preventive health programs. We aim to prepare and evaluate lyophilized combined inactivated viruses (bovine viral diarrhea virus [BVDV] genotypes 1 and 2, bovine herpes virus type 1.1 [BoHV-1.1], bovine parainfluenza-3 virus [BPI-3V], and bovine respiratory syncytial virus [BRSV]) vaccine using saponin as a solvent and adjuvant in cattle. Materials and Methods: Lyophilized Pneumo-5 vaccine was formulated to include the inactivated BVDV genotypes 1 and 2, BoHV-1.1, BPI-3V, and BRSV. The saponin solution was used as an adjuvant and solvent. The prepared vaccines were adjusted to contain 1- and 1.5-mg saponin/dose. It was evaluated for its sterility, safety, and potency in mice and calves. The antibody titers in vaccinated calves were measured by virus neutralization test and enzyme-linked immunosorbent assay (ELISA). Results: The Pneumo-5 vaccine was found to be free from any contaminants and safe in mice. Meanwhile, the vaccine showed safety in calves which inoculated intramuscularly with the double dose of the vaccines. The overall immune response reached its peak in the 2nd-month post-vaccination. The vaccine contained saponin 1.5 mg/dose reached its antibodies peak in the 4th-week post-vaccination. All groups of vaccinated calves with both concentrations of the saponin did not show statistical significance in antibody titers measured by serum neutralization test and/or ELISA. Conclusion: The prepared vaccine, namely Pneumo-5, and adjuvanted with either 1 or 1.5 mg/dose saponin was proved safe and potent for effectual protection of calves against BVDV genotypes 1 and 2, BoHV-1.1, BPI-3V, and BRSV.

Alloxan-induced diabetic thermal hyperalgesia, prophylaxis and phytotherapeutic effects of Rheum ribes L. in mouse model

Karim Raafat,Maha Aboul-Ela,Abdalla El-Lakany 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.8

Rheum ribes L., known as Syrian rhubarb, isused in traditional Lebanese folk medicine for the treatmentof diabetes. The present study aims to investigate theactivities of R. ribes aqueous extract for glucose homeostasis,in vivo antioxidant and diabetic neuropathy protectionin mice. The acute and the subacute effects of variousdoses of R. ribes on blood glucose and in vivo antioxidantactivity utilizing serum catalase level (CAT) were studiedin alloxan-diabetic mice. The high doses significantlylowered glucose level and increased serum CAT inalloxan-diabetic mice. Pretreatment with the extract priorto alloxination, protected the mice from acquiring diabetesand diabetic neuropathy. Treatment with the extract for8 weeks alleviated hyperalgesia in diabetic mice. Ourfindings provide clinicians with promising drugs intendedfor the management of the symptoms of diabetic complications. The protective activity of R. ribes against acquiringdiabetes and diabetic neuropathy might pave the wayfor preparing a prophylactic treatment for diabetes riskgroups.

Behavior of Solutions of a Fourth Order Difference Equation

Abo-Zeid, Raafat Department of Mathematics 2016 Kyungpook mathematical journal Vol.56 No.2

In this paper, we introduce an explicit formula for the solutions and discuss the global behavior of solutions of the difference equation $$x_{n+1}={\frac{ax_{n-3}}{b-cx_{n-1}x_{n-3}}}$$, $n=0,1,{\ldots}$ where a, b, c are positive real numbers and the initial conditions $x_{-3}$, $x_{-2}$, $x_{-1}$, $x_0$ are real numbers.

Intelligent Robust Control Design of a Precise Positioning System

Safanah M. Raafat,Rini Akmeliawati 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.5

This paper addresses an intelligent uncertainty function to improve the robust stability and performance of H∞ controlled system in terms of reduced conservatism. The system is identified, out-put performance and control signal requirements are controlled by proper selection of performance and control weighting functions. Adaptive Neuro Fuzzy Inference System (ANFIS) learns the uncertainty bounds of model uncertainty that results from unmodeled dynamics and parameter variations, then the developed uncertainty weighting function will be included in the synthesis of the H∞ controller. v-gap measure is utilized to validate the intelligent identified uncertainty bounds and measure the stability of the designed H∞ controlled system as well. Experimental results on a servo motion system reveal the advantages of combining intelligent uncertainty identification and robust control. Improved performance is achieved. The proposed approach also allows for iterative experiment design.

Synthesis of Thiazolo[4,5-d]pyrimidine Derivatives as Potential Antimicrobial Agents

Habib, Nargues S.,Soliman, Raafat,El-Tombary, Alaa A.,El-Hawash, Soad A.,Shaaban, Omaima G. 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12

In this study, we report the synthesis and antimicrobial evaluation of several new thiazolo[4,5-d]pyrimidine derivatives, namely 7-substituted amino-5-methyl-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-thiones 4a-e, 8, 13, 15, ethyl 2-cyano-2-(7-substituted-5-methyl-3-phenylthiazolo [4,5-d]-pyrimidin-2(3H)-ylidene)acetates 5a-b, 2-(7 -substituted-5-methyl-3-phenylthiazolo[4,5-d]pyrimidin-2(3H)-ylidene)malononitriles 6a-b, 5-methyl-7-morpholino-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-one 7, and 7-[4-(1-substituted-5-phenyl-4,5-dihydro-1H-pyrazolin-3-yl)anilino]-5-methyl-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-thiones 10-12. Some of the tested compounds were more active against C. albicans than E. coli and P. aeruginosa, and all were inactive against S. aureus.

Synthesis of Thiazolo[4,5-d]pyrimidine Derivatives as Potential Antimicrobial Agents

Nargues S. Habib,Raafat Soliman,Alaa A. El-Tombary,Soad A. El-Hawash,Omaima G. Shaaban 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12

In this study, we report the synthesis and antimicrobial evaluation of several new thiazolo[4,5- d]pyrimidine derivatives, namely 7-substituted amino-5-methyl-3-phenylthiazolo[4,5-d]pyrimidine- 2(3H)-thiones 4a-e, 8, 13, 15, ethyl 2-cyano-2-(7-substituted-5-methyl-3-phenylthiazolo [4,5-d]-pyrimidin-2(3H)-ylidene)acetates 5a-b, 2-(7-substituted-5-methyl-3-phenylthiazolo[4,5- d]pyrimidin-2(3H)-ylidene)malononitriles 6a-b, 5-methyl-7-morpholino-3-phenylthiazolo[4,5-d] pyrimidine-2(3H)-one 7, and 7-[4-(1-substituted-5-phenyl-4,5-dihydro-1H-pyrazolin-3-yl)anilino]-5- methyl-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-thiones 10-12. Some of the tested compounds were more active against C. albicans than E. coli and P. aeruginosa, and all were inactive against S. aureus.

Fast and Compact ASIC Implementation of SFlash New Signature Scheme

Mohamed M.Abdelhalim,Raafat S.Elfouly 보안공학연구지원센터 2009 International Journal of Security and Its Applicat Vol.3 No.4

The idea of using multivariate polynomials as public keys has attracted several cryptographers, SFlash signature scheme is a variant of the Matsumoto and Imai multivariate public Key cryptosystem and selected by NESSIE Consortium. In this paper we describe a hardware implementation of SFlash based on bit-parallel architectures to achieve high speed circuits for operations on Finite Fields which can be efficiently used as an authentication unit in wireless devices, smart cards and RFID networks. We have proposed a new generalization to Karatsuba-Ofman multiplier as the core of the design. An ASIC chip can be realized with 78K gates counts and 2.8 mm2 die size with 0.35 mm CMOS technology, with a maximum clock frequency 140 MHZ, which takes about 21.5 ms to sign 259-Bits data.

Dynamical Behavior of a Third-Order Difference Equation with Arbitrary Powers

Gumus, Mehmet,Abo-Zeid, Raafat,Ocalan, Ozkan Department of Mathematics 2017 Kyungpook mathematical journal Vol.57 No.2

The aim of this paper is to investigate the dynamical behavior of the difference equation $$x_{n+1}={\frac{{\alpha}x_n}{{\beta}+{\gamma}x^p_{n-1}x^q_{n-2}}},\;n=0,1,{\ldots}$$, where the parameters ${\alpha}$, ${\beta}$, ${\gamma}$, p, q are non-negative numbers and the initial values $x_{-2}$, $x_{-1}$, $x_0$ are positive numbers. Also, some numerical examples are given to verify our theoretical results.