Experimental investigation of the stress-strain behavior of FRP confined concrete prisms

Hosseinpour, F.,Abbasnia, R. Techno-Press 2014 Advances in concrete construction Vol.2 No.3

One of the main applications of FRP composites is confining concrete columns. Hence identifying the cyclic and monotonic stress-strain behavior of confined concrete columns and the parameters influencing this behavior is inevitable. Two significant parameters affecting the stress-strain behavior are aspect ratio and corner radius. The present study aims to scrutinize the effects of corner radius and aspect ratio on different aspects of stress-strain behavior of FRP confined concrete specimens (rectangular, square and circular). Hence 44 FRP confined concrete specimens were tested and the results of the tests were investigated. The findings indicated that for specimens with different aspect ratios, the relationship between the ultimate stress and the corner radius is linear and the variations of the ultimate stress versus the corner radius decreases as a result of an increase in aspect ratio. It was also observed that increase of the corner radius results in increase of the compressive strength and ultimate axial strain and increase of the aspect ratio causes an increase of the ultimate axial strain but a decrease of the compressive strength. Investigation of the ultimate condition showed that the FRP hoop rupture strain is smaller in comparison with the one obtained from the tensile coupon test and also the ultimate axial strain and confined concrete strength are smaller when a prism is under monotonic loading. Other important results of this study were, an increase in the axial strain during the early stage of unloading paths and increase of the confining effect of FRP jacket with the increase and decrease of the corner radius and aspect ratio respectively, a decrease in the slope of reloading branches with cycle repetitions and the independence of this trend from the variations of the aspect ratio and corner radius and also quadric relationship between the number of each cycle and the plastic strain of the same cycle as well as the independence of this relationship from the aspect ratio and corner radius.

Statistical evaluation of the monotonic models for FRP confined concrete prisms

Hosseinpour, Farid,Abdelnaby, Adel E. Techno-Press 2015 Advances in concrete construction Vol.3 No.3

FRP confining is a widely used method for seismic retrofitting of concrete columns. Several studies investigated the stress-strain behavior of FRP confined concrete prisms with square and rectangular sections both experimentally and analytically. In some studies, the monotonic stress-strain behavior of confined concrete was investigated and compressive strength models were developed. To study the reliability of these models, thorough statistical tests are required. This paper aims to investigate the reliability of the presented models using statistical tests including t-test, wilcoxon rank sum test, wilcoxon signed rank test and sign test with a level of significance of 5%. Wilk Shapiro test was also employed to evaluate the normality of the data distribution. The results were compared for different cross section and confinement types. To see the accuracy of the models when there were no significant differences between the results, the coefficient of confidence was used.

Analysis and design of centrifugal compressor for 10 MWe supercritical CO2 Brayton cycles

Javad Hosseinpour,Mekuannint Messele,ABRAHAM ENGEDA 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

The concept of a closed-loop s-CO 2 Brayton cycle is highly attractive and promising; however, there is yet a major hurdle to overcome, namely, the designing, developing, and testing of a reasonable size (10 MWe or higher) prototype of an s-CO 2 Brayton-cycle-based power gas turbine. In the present paper, two well-known closed-loop s-CO 2 Brayton cycles, the simple recuperated and recompression cycles, were reconfigured to generate 10 MW electric power. It was found that the thermal efficiency of simple and recompression cycle was 43.2 %, and 54.2 %, respectively. Further, a 1-D compressor design code was developed by avoiding condensation margin and the Widom region and validated with Eckardt Impeller-A to proceed and design a single-stage s-CO 2 impeller for the simple recuperated power cycle. The results show that the diffusion rate along the blades (W 2 /W 1 ) is fairly high for the designed compressor. Additionally, blade angle distribution and the performance plots were computed by utilizing the developed code and presented for the simple recuperated cycle. Lastly, the 3-D impeller was generated and CFD analysis was performed and the results are reported.

Determinants of Economic Growth in the Developing Countries: An Extreme Bounds Analysis

Fatimah Hosseinpour,Mansour Zarra-Nezhad,Sayed Aziz Arman,Ahmad Salahmanesh 중앙대학교 경제연구소 2019 Journal of Economic Development Vol.44 No.4

The present study aimed to test the hypothesis of inadequacy of growth theories in developing countries by identifying the robust determinants of economic growth under uncertainty in model selection. The extreme bounds analysis approach was adopted, and nearly 11 million regressions were estimated. Results showed that in developing countries, the behavior of some potential determinants of growth, such as corruption and bureaucracy quality, is against economic growth theories, and some of other variables are weak determinants of growth. The findings also confirmed the power of variables such as investment and trade proxies.

Direct shear behavior of concrete filled hollow steel tube shear connector for slim-floor steel beams

Emad Hosseinpour,Shahrizan Baharom,Wan Hamidon W. Badaruzzaman,Mahdi Shariati,Abdolrahim Jalali 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.4

In this paper, a hollow steel tube (HST) shear connector is proposed for use in a slim-floor system. The HST welded to a perforated steel beam web and embedded in concrete slab. A total of 10 push-out tests were conducted under static loading to investigate the mechanical behavior of the proposed HST connector. The variables were the shapes (circular, square and rectangular) and sizes of hollow steel tubes, and the compressive strength of the concrete. The failure mode was recorded as: concrete slab compressive failure under the steel tube and concrete tensile splitting failure, where no failure occurred in the HST. Test results show that the square shape HST in filled via concrete strength 40 MPa carried the highest shear load value, showing three times more than the reference specimens. It also recorded less slip behavior, and less compressive failure mode in concrete underneath the square hollow connector in comparison with the circular and rectangular HST connectors in both concrete strengths. The rectangular HST shows a 20% higher shear resistance with a longer width in the load direction in comparison with that in the smaller dimension. The energy absorption capacity values showed 23% and 18% improvements with the square HST rather than a headed shear stud when embedded in concrete strengths of 25 MPa and 40 MPa, respectively. Moreover, an analytical method was proposed and predicts the shear resistance of the HST shear connectors with a standard deviation of 0.14 considering the shape and size of the connectors.

A SYSTEMATIC ANALYSIS OF THE EFFECTS OF MOBILE PHONE APPLICATIONS ON PHYSICAL ACTIVITY

Masoumeh Hosseinpour,Ralf Terlutter,Holger Roschk 글로벌지식마케팅경영학회 2020 Global Marketing Conference Vol.2020 No.11

Application of Adaptive Neuro-Fuzzy Inference System for Road Accident Prediction

Mehdi Hosseinpour,Ahmad Shukri Yahaya,Seyed Mohammadreza Ghadiri,Joewono Prasetijo 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.7

Since the last two decades, several modeling approaches have been developed in road safety literature to establish the relationship between traffic accidents and road characteristics. However, to the best of the authors’ knowledge, no extensive research work has been published on application of Adaptive Neuro-fuzzy Inference System (ANFIS) on road accident modelling. Therefore, the present paper aims to develop an ANFIS technique for modelling traffic accidents as a function of road and roadside characteristics. To achieve the objective, accident data and road characteristics were collected over a two-year period along the Qazvin-Loshan intercity roadway in Iran. The candidate set of explanatory variables included the Mean Horizontal Curvature (MHC), Shoulder Width (SW), Road Width (RW), Land Use (LU), Access Points (AP), Longitudinal Grade (LG), and Horizontal Curve Density (HCD). The results showed that RW, SW, LU, and AP significantly affected accident frequencies. Using statistical performance indices, the ANFIS model was compared with the Poisson, negative binomial, and non-linear exponential regression models. Based on the comparative results, the proposed model had higher prediction performance than the other three traditional models which has been widely used in the literature. To conclude, the proposed model could be used as a robust approach to handle uncertainty and complexity existed in accident data. In general, ANFIS model can be an effective tool for transportation agencies since intervention decisions and plans aiming at improving road safety depend on the prediction capabilities of a system.

CuInS2 nanostructures: Synthesis, characterization, formation mechanism and solar cell applications

S.M. Hosseinpour-Mashkani,M. Salavati-Niasari,F. Mohandes 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

This investigation reports the synthesis of CuInS2 nanostructures by using [Cu(gly)2] via a microwave-assisted method. CuInS2 nanostructures were obtained from a mixture of InCl3, [Cu(gly)2] and different sulfur sources in propylene glycol. In this work, the effect of different sulfur sources on the morphology of CuInS2 nanostructures was studied. CuInS2 nanostructures were characterized by XRD, SEM, TEM, EDS, and FT-IR. To fabricate a standard solar cell, CdS film was directly deposited on top of the CIS film prepared by Doctor’s blade method through chemical bath deposition. The as-deposited CdS/CuInS2 film was used for the photovoltaic measurements.

SARS-CoV-2 fecal shedding pattern in pediatric patients with acute COVID-19 or COVID-19- associated multisystem inflammatory syndrome

Setareh Mamishi,Fatemeh Jalali,Sepideh Benvari,Babak Pourakbari,Mohammad Reza Abdolsalehi,Reihaneh Hosseinpour Sadeghi Reihaneh Hosseinpour,Mohammad Shahbabaie,Amene Navaeian,Shima Mahmoudi 대한소아청소년과학회 2023 Clinical and Experimental Pediatrics (CEP) Vol.66 No.8

Preemptive Use of Ketamine on Post Operative Pain of Appendectomy

Behdad, Akbar,Hosseinpour, Mehrdad,Khorasani, Parastoo The Korean Pain Society 2011 The Korean Journal of Pain Vol.24 No.3

Background: Although early reviews of clinical findings were mostly negative, there is still a widespread belief for the efficacy of preemptive analgesia among clinicians. In this study, we evaluated whether the preemptive use of ketamine decreases post operative pain in patients undergoing appendectomy. Methods: In double-blind, randomized clinical trials, 80 adult male patients undergoing an operation for acute appendicitis were studied. Patients were randomly assigned to two groups. In the operating room, patients in the ketamine group received 0.5 mg/kg of ketamine IV 10 minutes before the surgical incision. In the control group, 0.5 mg/kg of normal saline was injected. The pain intensity was assessed at time 0 (immediately after arousal) and 4, 12, and 24 hours postoperatively using the 10 points visual analogue scale (VAS). Results: Eighty patients (40 for both groups) were enrolled in this study. For all of the evaluated times, the VAS score was significantly lower in the ketamine group compared to the control. The interval time for the first analgesic request was $23.1{\pm}6.7$ minutes for the case group and $18.1{\pm}7.3$ minutes for the control (P = 0.02). The total number of pethidine injections in the first 24 hours postoperatively was $0.6{\pm}0.6$ for the case group and $2.0{\pm}0.8$ for the controls (P = 0.032). There were no drug side effects for the case group. Conclusions: A low dose of intravenously administered ketamine had a preemptive effect in reducing pain after appendectomy.