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Practical relations to quantify the amount of damage of SWRCFs using pushover analysis
Habibi, Ali Reza,Samadi, Mohammad,Izadpanah, Mehdi Techno-Press 2020 Advances in concrete construction Vol.10 No.3
Quantifying the amount of damage of structures under earthquakes is an interesting issue that researchers have attended on and have presented some damage indices. Whereas a lot of damage indices have been introduced based on nonlinear dynamic analysis, computational effort, the calculus complicacy and time-consuming of this analysis are the main drawbacks to widespread use of these indices. The objective of this study is to quantify the damage of Shear Wall Reinforced Concrete Frames (SWRCFs) based on pushover analysis as a procedure that can reflect the behavior of structures from elastic to collapse. For this purpose, firstly, several SWRCFs are designed and the capacity spectrum of each one is achieved via pushover analysis. After that, the static damage indices of the designed frames are obtained. Then, nonlinear dynamic analyses are performed on these frames and the Park and Ang damage index as the basis damage criterion is achieved. Afterward, some relations are presented to predict the dynamic damage of these frames via pushover analysis. Eventually, to confirm the validity of the proposed relations, the values of Park and Ang damage index of three new SWRCFs are acquired once utilizing nonlinear dynamic analysis and again applying the introduced relations. Outcomes prove the validity of some presented damage indices.
Mohammad Hossein Habibi,Reza Sheibani 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.1
Silver-doped zinc oxide (SDZO) films have been grown on glass substrate by a novel combination of sol–gel and photochemical deposition processes (SGPD). The effect of sintering on structural, electrical and optical properties was investigated. The films were characterized by UV–vis absorption spectroscopy (UV–vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The result of X-ray photoelectron spectroscopy (XPS) revealed that the binding energy of Ag 3d5/2 for SDZO shifts remarkably to the lower binding energy compared to the pure metallic Ag due to the interaction between silver and zinc oxide. The XRD spectra of the SDZO films indicate that silver was incorporated in the hexagonal crystal structure of zinc oxide. SEM micrographs show the uniform distribution of spherical grains of about 73 nm grain size for the pure zinc oxide thin films. The results indicated that silver doping photochemical deposition was a feasible method to tune the optical properties of zinc oxide nanostructures. SDZO films coated on glass were applied for the photodegradation of mercaptan in water. SDZO films were applied for degradation of mercaptobenzoxazole which reduced the mercaptan concentration to more than 98%.
Optimal architecture of heat generating pieces in a fin
Mohammad Reza Hajmohammadi,Sadegh Poozesh,S. Salman Nourazar,Ali Habibi Manesh 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.4
This paper documents the optimal architecture of heat generating pieces connected to and cooled in a circular-shaped fin. Relying on the constructal theory, the optimal distribution of multiple heat sources is obtained by minimizing the thermal resistance of the fin. Since the heat sources are contemplated as electronic devices with uniform heat generation, the minimization of the thermal resistance is indicated by minimization of the hot spot (peak) temperature. Temperature fields in the fin and in the heat sources are calculated using a finite elements approach of MATLAB PDE toolbox. Comparison among the considered configurations reveals that the regular configurations of the heat sources commonly used in cooling industry are not optimal and must be avoided. Optimal configurations such as triangular arrangement of heat sources are proposed to replace the unfavorable configurations.
An Experimental Investigation to Calculate Flow Resistance in a Steep River
Mahdi Habibi,Mohammad Reza Namaee,Mojtaba Saneie 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.4
High gradient streams are characterised by steep slopes, coarse bed material with non-uniform size distribution, flash floodsand flow depths of magnitude comparable to the bed material size. Another characteristic of high gradient streams isdevelopment of armor layers with cobbles and boulders. In these streams, it is often difficult to measure water discharge orflow velocity directly, particularly at high flows; instead, it is necessary to use the indirect methods in which flow velocity anddischarge is calculated using a flow resistance predictor. The problem of predicting flow resistance in high gradient alluvialchannels with sufficient accuracy is of great interest to hydraulic engineers and is essential for the effective design of waterresourcesrelated projects. In this paper, the flow resistance of a steep river with coarse gravel bed material has beeninvestigated by using 75 accurate measured hydraulic data in a relatively wide flume with different coarse gravel bedmaterials, flow rates and longitudinal slopes. The main purpose of this article reviews the ability of the resistance empiricalequations to predict mean flow velocity in gravel river beds. Also, based on measured data, a new equation to predict the flowresistance in steep river has been proposed. This equation along with the other empirical equations has been used to predict theparameters introducing the flow resistance in steep rivers including Manning roughness coefficient, mean flow velocity andDarcy-Weisbach roughness coefficient. The results were compared with measured and calculated hydraulic data and the bestequations to predict the Manning’s roughness coefficient in a steep river with coarse gravel bed material are introduced. Finally in order to show the generality and accuracy of the proposed equation, it has been used for the other field data and theresults have been discussed.
Reliability analysis of double-layer domes with stochastic geometric imperfections
Gordini, Mehrdad,Habibi, Mohammad Reza,Sheidaii, Mohammad Reza,Tahamouliroudsari, Mehrzad Techno-Press 2017 Advances in computational design Vol.2 No.2
This study aimed to investigate the effect of initial member length an imperfection in the load carrying capacity of double-layer domes space structures. First, for the member length imperfection of each member, a random number is generated from a normal distribution. Thereupon, the amount of the imperfection randomly varies from one member to another. Afterwards, based on the Push Down analysis, the collapse behavior and the ultimate capacity of the considered structure is determined using nonlinear analysis performed by the OpenSees software and this procedure is repeated numerous times by Monte Carlo simulation method. Finally, the reliability of structures is determined. The results show that the collapse behavior of double-layer domes space structures is highly sensitive to the random distribution of initial imperfections.
Mohsen Tabasi,Mohammad Reza Asadi Karam,Mehri Habibi,Mir Saeed Yekaninejad,Saeid Bouzari 질병관리본부 2015 Osong Public Health and Research Persptectives Vol.6 No.4
Objectives: Urinary tract infection caused by uropathogenic Escherichia coli (UPEC) strains is one of the most important infections in the world. UPEC encode widespread virulence factors closely related with pathogenesis of the bacteria. The purpose of this study was to evaluate the presence of different phenotypic virulence markers in UPEC isolates and determine their correlation with antibiotic resistance pattern. Methods: UPEC isolates from patients with different clinical symptoms of UTI were collected and screened for biofilm and hemolysin production, mannose resistant, and mannose sensitive hemagglutination (MRHA and MSHA, respectively). In addition, antimicrobial resistance pattern and ESBL-producing isolates were recorded. Results: Of the 156 UPEC isolates, biofilm and hemolysin formation was seen in 133 (85.3%) and 53 (34%) isolates, respectively. Moreover, 98 (62.8%) and 58 (37.2%) isolates showed the presence of Types 1 fimbriae (MSHA) and P fimbriae (MRHA), respectively. Our results also showed a relationship between biofilm formation in UPEC isolated from acute cystitis patients and recurrent UTI cases. Occurrence of UTI was dramatically correlated with the patients’ profiles. We observed that the difference in antimicrobial susceptibilities of the biofilm and nonbiofilm former isolates was statistically significant. The UPEC isolates showed the highest resistance to ampicillin, tetracycline, amoxicillin, and cotrimoxazole. Moreover, 26.9% of isolates were ESBL producers. Conclusion: This study indicated that there is a relationship between the phenotypic virulence traits of the UPEC isolates, patients’ profiles, and antibiotic resistance. Detection of the phenotypic virulence factors could help to improve understanding of pathogenesis of UPEC isolates and better medical intervention.