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Classical shell theory for instability analysis of concrete pipes conveying nanofluid
Reza Keikha,Ali Heidari,Hamidreza Hosseinabadi,Mohammad Salkhordeh Haghighi 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.22 No.2
This paper deals with the instability analysis of concrete pipes conveying viscous fluid-nanoparticle mixture. The fluid is mixed by AL2O3 nanoparticles where the effective material properties of fluid are obtained by mixture rule. The applied force by the internal fluid is calculated by Navier-Stokes equation. The structure is simulated by classical cylindrical shell theory and using energy method and Hamilton's principle, the motion equations are derived. Based on Navier method, the critical fluid velocity of the structure is calculated and the effects of different parameters such as fluid velocity, volume percent of nanoparticle in fluid and geometrical parameters of the pipe are considered. The results present that with increasing the volume percent of nanoparticle in fluid, the critical fluid velocity increase.
Numerical study for vibration response of concrete beams reinforced by nanoparticles
Heidari, Ali,Keikha, Reza,Haghighi, Mohammad Salkhordeh,Hosseinabadi, Hamidreza Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.3
Vibration of concrete beams reinforced by agglomerated silicon dioxide ($SiO_2$) nanoparticles is studied based on numerical methods. The structure is simulated by Euler-Bernoulli beam model and the Mori-Tanaka model is used for obtaining the effective material properties of the structure. The concrete beam is located in soil medium which is modeled by spring elements. The motion equations are derived based on energy method and Hamilton's principle. Based on exact solution, the frequency of the structure is calculated. The effects of different parameters such as volume percent of $SiO_2$ nanoparticles and agglomeration, soil medium and geometrical parameters of beam are shown on the frequency of system. The results show that with increasing the volume percent of $SiO_2$ nanoparticles, the frequency increases.
Numerical study for vibration response of concrete beams reinforced by nanoparticles
Ali Heidari,Reza Keikha,Mohammad Salkhordeh Haghighi,Hamidreza Hosseinabadi 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.3
Vibration of concrete beams reinforced by agglomerated silicon dioxide (SiO2) nanoparticles is studied based on numerical methods. The structure is simulated by Euler-Bernoulli beam model and the Mori-Tanaka model is used for obtaining the effective material properties of the structure. The concrete beam is located in soil medium which is modeled by spring elements. The motion equations are derived based on energy method and Hamilton’s principle. Based on exact solution, the frequency of the structure is calculated. The effects of different parameters such as volume percent of SiO2 nanoparticles and agglomeration, soil medium and geometrical parameters of beam are shown on the frequency of system. The results show that with increasing the volume percent of SiO2 nanoparticles, the frequency increases.
Kadeh, Hamideh,Saravani, Shirin,Heydari, Fatemeh,Keikha, Mohammad,Rigi, Vahab Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15
Background: Matrix metalloproteinases (MMPs) are a family of zinc metalloproteinases capable of degrading components of connective tissues. MMP-10 is frequently expressed in human cancers. The aim of this study was to immunohistochemically evaluate its expression in oral squamous cell carcinoma (OSCC) and verrucous carcinoma (OVC). Materials and Methods: A retrospective analysis of 73 samples (31 OSCC, 22 OVC and 20 non-neoplastic epithelium) was performed. All samples were immunohistochemically stained with monoclonal MMP-10 antibody and expression levels and staining intensity were evaluated with respect to microscopic features. Data were analyzed by SPSS (V.21), Mann-Whitney and Kruskal Wallis tests. Results: MMP-10 was detected in all OSCC and OVC cases. The expression of MMP-10 in OSCC was intensive (score 3) and in OVC was low and moderate (score 1 and score 2) more frequently. Non- neoplastic epithelium did not show MMP-10 expression. Differences between groups was statistically significant (p<0.05). However, the expression of MMP-10 was not obviously different between various grades of OSCC. Conclusions: According to our study, MMP-10 protein can be important possible factor in the transformation of normal oral epithelium to OVC and OSCC, also the level of MMP-10 expression at invasion front of the lesions can be helpful in the differentiation of OVC and OSCC.
Investigation of key parameters influence on performance of direct ethanol fuel cell (DEFC)
Saeed Heysiattalab,Mehdi Safari,Mohsen Shakeri,M.M. Keikha 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.4
Direct ethanol fuel cell has been declared as a new alternative for other fuel cells such as direct methanol fuel cell and proton exchange membrane fuel cells. In this paper, effects of key parameters such as temperature, anode and cathode flow rate, molarity and cathode pressure have been investigated on ethanol fuel cell performance. Maximum power density and fuel cell performance will increase by temperature rising because of ion conductivity, diffusion and reaction rate increase. Molarity augmentation will increase ethanol concentration in catalyst layer and reaction rate which leads to better performance of the cell. Anode and cathode flow rate and cathode pressure will slightly increase fuel cell performance.