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Plasticity Constitutive Modeling of Partially Confined Concrete with Steel Jacketing
Erfan Shafei,Javad Mokari Rahmdel 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7
Current research offers experimental and numerical investigation on concrete blocks with partial steel jackets, which endures axial compression. Experimental procedure provides the primary data for calibration of proposed model. Specimens have various steel jacketing ratios and the load is axial compression. The recorded data are strain components, elongation and the resisted force in experiment. A continuous cap plasticity surface expresses the non-uniform expansion and contraction of concrete beside an isotropic damage law that models the strength degradation using Abaqus® code. In presented mathematical model, the contraction and dilation of concrete is function of lateral pressure provided by steel jackets. The confining pressure is non-uniform due to discrete arrangement of steel ties in jacket and yielding of steel as concrete expands. Model provides parametric curves in order to design the confined-to-unconfined strength and ductility capacities of confined concrete. The presented numerical model is in close agreement with experimental results based on acquired results. We derive finally parametric curves for ductility and strength of confined concrete for various jacketing ratios.
Some Applications of Generalized Closed Sets in Fuzzy Topological Spaces
El-Shafei, M.E. Department of Mathematics 2005 Kyungpook mathematical journal Vol.45 No.1
In this paper we introduce the notions of g-regularity and g-normality in fuzzy topological spaces. We obtain some characterizations and several preservation theorems of such spaces.
Two notes on ``On soft Hausdorff spaces"
M. E. El-Shafei,M. Abo-Elhamayel,T. M. Al-shami 원광대학교 기초자연과학연구소 2018 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.16 No.3
One of the well known results in general topology says that every compact subset of a Hausdorff space is closed. This result in soft topology is not true in general as demonstrated throughout this note. We begin this investigation by showing that [Theorem 3.34, p.p.23] which proposed by Varol and Ayg\"{u}n [7] is invalid in general, by giving a counterexample. Then we derive under what condition this result can be generalized in soft topology. Finally, we evidence that [Example 3.22, p.p. 20] which introduced in [7] is false, and we make a correction for this example to satisfy a condition of soft Hausdorffness.
RS-Compactness in L-fuzzy Topological Spaces
M. E. EL-Shafei,I. M. Hanafy,A. I. Aggour 경북대학교 자연과학대학 수학과 2002 Kyungpook mathematical journal Vol.42 No.2
The concept of RS-compactness is introduced and studied in L-fts's. We give some characterizations of RS-compactness in terms of regular closed, semiopen and β-open L-fuzzy sets. We also characterize RS-compactness in the sense of convergent prefilterbasis and by means of finite intersection property. We investigate the image and the inverse image of RS-compact spaces under some types of functions.
El-Rahman, Atef Abd El-Mohsen Abd,El-Shafei, Sally Mohamed Abd El-Aziz,Ivanova, Elena Vladimirovna,Fattakhova, Alfia Nurlimanovna,Pankova, Anna Victorovna,El-Shafei, Mohamed Abd El-Aziz,El-Morsi, El-M Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.17
Trichoderma spp. are known as a rich source of secondary metabolites with biological activity belonging to a variety of classes of chemical compounds. These fungi also are well known for their ability to produce a wide range of antibiotic substances and to parasitize other fungi. In search for new substances, which might act as anticancer agents, the overall objective of this study was to investigate the cytotoxic effects of Trichoderma harzianum and Trichoderma asperellum cultural filtrates against human cervical and breast cancer cell lines (HeLa and MCF-7 cells respectively). To achieve this objective, cells were exposed to 20, 40, 60, 80 and 100 mg/ml of both T. harzianum cultural filtrate (ThCF) and T. asperellum cultural filtrate (TaCF) for 24h, then the cell viability and the cytotoxic responses were assessed by using trypan blue and 3-(4,5-dimethylthiazol-2yl)-2,5-biphenyl tetrazolium bromide (MTT) assays. Morphological changes in cells were investigated by phase contrast inverted microscopy. The results showed that ThCF and TaCF significantly reduce the cell viability, have cytotoxic effects and alter the cellular morphology of HeLa and MCF-7 cells in a concentration dependent manner. A concentration of 80 and 100mg/ml of ThCF resulted in a sharp decline in the cell viability percent of HeLa and MCF-7 respectively (25.2%, 26.5%) which was recorded by trypan blue assay. The half-maximal inhibitory concentrations ($IC_{50}$) of ThCF and TaCF in HeLa and MCF-7 were recorded as 16.6, 12.0, 19.6 and 0.70mg/ml respectively by MTT assay. These results revealed that ThCF and TaCF have a substantial ability to reduce the viability and proliferation of human cervical and breast cancer cells.
Pouretedal, H.R.,Shafeie, A.,Keshavarz, M.H. Korean Chemical Society 2012 대한화학회지 Vol.56 No.4
The tin (IV) oxide nanoparticles are prepared by controlled precipitation method and calcined at temperatures of $200-600^{\circ}C$. The prepared $SnO_2$ nanoparticles characterized by XRD patterns, TEM image, IR and UV-Vis spectra. The XRD patterns and TEM image show the tetragonal structure and spherical morphology for $SnO_2$ nanoparticles, respectively. The photocatalytic activity of the prepared $SnO_2$ nanoparticles studied in degradation reaction of methylene blue (MB). The results show the size of nanoparticles, band-gap energy and photocatalytic activity of $SnO_2$ depends on the calcinations temperature. The $SnO_2$ nanoparticles calcined at $500^{\circ}C$ indicated the highest photoreactivity. Also, the zero-valent tin (ZVT) nanoparticles with tetragonal structure are prepared by a reducing agent and used as a catalyst in degradation of MB. In basic pH of 11, the degradation >95% of MB at time 150 min obtained at presence of ZVT nanoparticles.
Optimal shape design of contact systems
Mahmoud, F.F.,El-Shafei, A.G.,Al-Saeed, M.M. Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.24 No.2
Many applications in mechanical design involve elastic bodies coming into contact under the action of the applied load. The distribution of the contact pressure throughout the contact interface plays an important role in the performance of the contact system. In many applications, it is desirable to minimize the maximum contact pressure or to have an approximately uniform contact pressure distribution. Such requirements can be attained through a proper design of the initial surfaces of the contacting bodies. This problem involves a combination of two disciplines, contact mechanics and shape optimization. Therefore, the objective of the present paper is to develop an integrated procedure capable of evaluating the optimal shape of contacting bodies. The adaptive incremental convex programming method is adopted to solve the contact problem, while the augmented Lagrange multiplier method is used to control the shape optimization procedure. Further, to accommodate the manufacturing requirements, surface parameterization is considered. The proposed procedure is applied to a couple of problems, with different geometry and boundary conditions, to demonstrate the efficiency and versatility of the proposed procedure.
Shahraki, Samira,Mohebbati, Reza,Shafei, Mohammad Naser,Mahmoudi, Mahmoud,Hosseinian, Sara,Parhizgar, Soghra,Yazd, Zohreh Naji Ebrahimi,Heravi, Nazanin Entezari,Abadi, Reza Nejad Shahrokh,Khajavirad, KOREAN PHARMACOPUNCTURE INSTITUTE 2019 Journal of pharmacopuncture Vol.22 No.3
Objective: In the current work, we investigated the cytotoxic and apoptotic effects of Thymoquinone (TQ), an active compound of Nigella sativa (N. sativa) and Cis-platinum, on normal renal epithelial (GP-293) and human renal adenocarcinoma cell lines (ACHN). Methods: GP-293 and ACHN cell lines were cultured in Dulbecco's modified Eagle's medium (DMEM) with 10% Fetal bovine serum (FBS) and 1% penicillin plus streptomycin antibiotic. The MTT assay was used for cellular viability assessment. Viability of cells was observed using inverted light microscope 24, 48 and 72 h after exposure of the cells to various concentrations of TQ (1, 2.5, 5, 10, 50 and $100{\mu}g/ml$) and Cis-platinum (0.5, 1, 1.5, 2, 3, 6 and $12.5{\mu}g/ml$). Moreover, apoptosis was analyzed with a flow-cytometry method. The untreated cells were considered as control group. Results: Morphological changes such as reduced cell number and increased intercellular distance and reduced cell viability in ACHN and GP-293cell lines were observed in both TQ and Cis- platinum groups; however, Cis-platinum had greater effect on ACHN cell line than GP-293 cell line. In addition, GP-293 cell line was more sensitive to TQ compared to ACHN cell line. Furthermore, TQ and Cis-platinum had apoptotic effects on both ACHN and GP-293 cell lines. Conclusion: Our findings demonstrated that TQ and Cis-platinum had cytotoxic and apoptotic effects on both cell lines, However, GP-293 cell line was more sensitive to TQ. Additionally, Cis-platinum was more effective on ACHN cell line than on GP-293 cell line.
Javad Mokari Rahmdel,Erfan Shafei 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.3
Conventional reinforced concrete design codes assume ideal strain evolution in semi-deep beams with externally bonded fiber-reinforced polymer (EB-FRP) web strips. However, there is a strain interaction between internal stirrups and web strips, leading to a notable difference between code-based and experimental shear strengths. Current study provides an experiment-verified detailed numerical framework to assess the potential strain interaction under quasi-static monotonic load. Based on the observations, steel stirrups are effective only for low EB-FRP amounts and the over-strengthening of semi-deep beams prevents the stirrups from yielding, reducing its shear strength contribution. A notable difference is detected between the code-based and the study-based EB-FRP strain values, which is a function of the normalized FRP stress parameter. Semianalytical relations are proposed to estimate the effective strain and stress of the components considering the potential strain interaction. For the sake of simplification, a linearized correction factor is proposed for the EB-FRP web strip strain, assuming its restraining effect as constant for all steel stirrup amounts.