An Analysis of Individual and Social Factors Affecting Occupational Accidents

Barkhordari, Amir,Malmir, Behnam,Malakoutikhah, Mahdi Occupational Safety and Health Research Institute 2019 Safety and health at work Vol.10 No.2

Background: Workforce health is one of the primary and most challenging issues, particularly in industrialized countries. This article aims at modeling the major factors affecting accidents in the workplace, including general health, work-family conflict, effort-reward imbalance, and internal and external locus of control. Methods: A cross-sectional study was conducted in Esfahan Steel Company in Iran. A total of 450 participants were divided into two groups-control and case-and the questionnaires were distributed among them. Data were collected through a 7-part questionnaire. Finally, the results were analyzed using SPSS 22.0 and Amos software. Results: All the studied variables had a significant relationship with the accident proneness. In the case group, general health with a coefficient of -0.37, worke-family conflict with 0.10, effort-reward imbalance with 0.10, internal locus of control with -0.07, and external locus of control with 0.40 had a direct effect on occupational stress. Occupational stress also had a positive direct effect on accident proneness with a coefficient of 0.47. In addition, fitness indices of control group showed general health (-0.35), worke-family conflict (0.36), effort-reward imbalance (0.13), internal locus of control (-0.15), and external locus of control (0.12) have a direct effect on occupational stress. Besides, occupational stress with a coefficient of 0.09 had a direct effect on accident proneness. Conclusion: It can be concluded that although previous studies and the present study showed the effect of stress on accident and accident proneness, some hidden and external factors such as work-family conflict, effort-reward imbalance, and external locus of control that affect stress should also be considered. It helps industries face less occupational stress and, consequently, less occurrence rates of accidents.

An Analysis of Individual and Social Factors Affecting Occupational Accidents

Amir Barkhordari,Behnam Malmir,Mahdi Malakoutikhah 한국산업안전보건공단 산업안전보건연구원 2019 Safety and health at work Vol.10 No.2

Background: Workforce health is one of the primary and most challenging issues, particularly in industrialized countries. This article aims at modeling the major factors affecting accidents in the workplace, including general health, workefamily conflict, effortereward imbalance, and internal and external locus of control. Methods: A cross-sectional study was conducted in Esfahan Steel Company in Iran. A total of 450 participants were divided into two groupsdcontrol and casedand the questionnaires were distributed among them. Data were collected through a 7-part questionnaire. Finally, the results were analyzed using SPSS 22.0 and Amos software. Results: All the studied variables had a significant relationship with the accident proneness. In the case group, general health with a coefficient of e0.37, workefamily conflict with 0.10, effortereward imbalance with 0.10, internal locus of control with e0.07, and external locus of control with 0.40 had a direct effect on occupational stress. Occupational stress also had a positive direct effect on accident proneness with a coefficient of 0.47. In addition, fitness indices of control group showed general health (e0.35), workefamily conflict (0.36), effortereward imbalance (0.13), internal locus of control (e0.15), and external locus of control (0.12) have a direct effect on occupational stress. Besides, occupational stress with a coefficient of 0.09 had a direct effect on accident proneness. Conclusion: It can be concluded that although previous studies and the present study showed the effect of stress on accident and accident proneness, some hidden and external factors such as workefamily conflict, effortereward imbalance, and external locus of control that affect stress should also be considered. It helps industries face less occupational stress and, consequently, less occurrence rates of accidents.

Ensemble techniques and hybrid intelligence algorithms for shear strength prediction of squat reinforced concrete walls

Mohammad Sadegh Barkhordari,Leonardo M. Massone Techno-Press 2023 Advances in computational design Vol.8 No.1

Squat reinforced concrete (SRC) shear walls are a critical part of the structure for both office/residential buildings and nuclear structures due to their significant role in withstanding seismic loads. Despite this, empirical formulae in current design standards and published studies demonstrate a considerable disparity in predicting SRC wall shear strength. The goal of this research is to develop and evaluate hybrid and ensemble artificial neural network (ANN) models. State-of-the-art population-based algorithms are used in this research for hybrid intelligence algorithms. Six models are developed, including Honey Badger Algorithm (HBA) with ANN (HBA-ANN), Hunger Games Search with ANN (HGS-ANN), fitness-distance balance coyote optimization algorithm (FDB-COA) with ANN (FDB-COA-ANN), Averaging Ensemble (AE) neural network, Snapshot Ensemble (SE) neural network, and Stacked Generalization (SG) ensemble neural network. A total of 434 test results of SRC walls is utilized to train and assess the models. The results reveal that the SG model not only minimizes prediction variance but also produces predictions (with R²= 0.99) that are superior to other models.

Failure Mode Detection of Reinforced Concrete Shear Walls Using Ensemble Deep Neural Networks

Mohammad Sadegh Barkhordari,Leonardo M. Massone 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.4

Reinforced concrete structural walls (RCSWs) are one of the most efficient lateral force-resisting systems used in buildings, providing sufficient strength, stiffness, and deformation capacities to withstand the forces generated during earthquake ground motions. Identifying the failure mode of the RCSWs is a critical task that can assist engineers and designers in choosing appropriate retrofitting solutions. This study evaluates the efficiency of three ensemble deep neural network models, including the model averaging ensemble, weighted average ensemble, and integrated stacking ensemble for predicting the failure mode of the RCSWs. The ensemble deep neural network models are compared against previous studies that used traditional well-known ensemble models (AdaBoost, XGBoost, LightGBM, CatBoost) and traditional machine learning methods (Naïve Bayes, K-Nearest Neighbors, Decision Tree, and Random Forest). The weighted average ensemble model is proposed as the best-suited prediction model for identifying the failure mode since it has the highest accuracy, precision, and recall among the alternative models. In addition, since complex and advanced machine learning-based models are commonly referred to as black-box, the SHapley Additive exPlanation method is also used to interpret the model workflow and illustrate the importance and contribution of the components that impact determining the failure mode of the RCSWs.

Combined TGE-SGE Expression of Novel PAI-1-Resistant t-PA in CHO DG44 Cells Using Orbitally Shaking Disposable Bioreactors

( Fatemeh Davami ),( Farzaneh Barkhordari ),( Mahmoud Alebouyeh ),( Ahmad Adeli ),( Fereidoun Mahboudi ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.12

An important modification of thrombolytic agents is resistance to plasminogen activator inhibitor-1 (PAI-1). In previous studies, a new truncated PAI-1-resistant variant was developed based on deletion of the first three domains in t-PA and the substitution of KHRR 128-131 amino acids with AAAA in the truncated t-PA. The novel variant expressed in a static culture system of Chinese Hamster Ovary (CHO) DG44 cells exhibited a higher resistance to PAI-1 when compared with the full-length commercial drug; Actylase. In the present study, the truncatedmutant protein was expressed in CHO DG44 cells in 50 ml orbital shaking bioreactors. The final yield of the truncatedmutant in the culture was 752 IU/ml, representing a 63% increase compared with the static culture system. Therefore, these results suggest that using the combined features of a transient and stable expression system is feasible for the production of novel recombinant proteins in the quantities needed for preclinical studies.

Behavior of FRP-reinforced steel plate shear walls with various reinforcement designs

Mehdi Seddighi,Mohammad A. Barkhordari,S.A.A. Hosseinzadeh 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.5

The nonlinear behavior of single- and multi-story steel plate shear walls (SPSWs) strengthened with three different patterns of fiber reinforced polymer (FRP) laminates (including single-strip, multi-strip and fully FRP-strengthened models) is studied using the finite element analysis. In the research, the effects of orientation, width, thickness and type (glass or carbon) of FRP sheets as well as the system aspect ratio and height are investigated. Results show that, despite an increase in the system strength using FRP sheets, ductility of reinforced SPSWs is decreased due to the delay in the initiation of yielding in the infill wall, while their initial stiffness does not change significantly. The content/type/reinforcement pattern of FRPs does affect the nonlinear behavior characteristics and also the mode and pattern of failure. In the case of multi-strip and fully FRP-strengthened models, the use of FPR sheets almost along the direction of the infill wall tension fields can maximize the effectiveness of reinforcement. In the case of single-strip pattern, the effectiveness of reinforcement is decreased for larger aspect ratios. Moreover, a relatively simplified and approximate theoretical procedure for estimating the strength of SPSWs reinforced with different patterns of FRP laminates is presented and compared with the analytical results.

Robust Output Observer-Based Guaranteed Cost Control of a Class of Uncertain Switched Neutral Systems with Interval Time-Varying Mixed Delays

Hamid Ghadiri,Mohammad Reza Jahed-Motlagh,Mojtaba Barkhordari Yazdi 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.6

This paper considers the robust output observer-based guaranteed cost control (GCC) for a class of un-certain switched neutral systems (USNSs) where delays are discrete, neutral, and time-varying. This research emphasizes the cases where uncertainties are norm-bounded and time-varying. The GCC is the problem of obtaining an adequate level of performance index in addition to the exponential stability from a practical perspective. First, delay-dependent sufficient conditions are suggested using the average dwell time approach and the piecewise Lyapunov function technique in terms of a set of linear matrix inequalities to guarantee the robust exponential stability via the output observer-based controller. The problem of uncertainty in USNSs is solved by designing a robust output observer-based control and applying Yakubovich lemma. Then, the corresponding conditions are obtained for USNSs via the applied controller under the GCC. The controller and the observer in an observer-based control problem cannot be designed separately, meaning that a separation principle does not hold in this re-search. Finally, a numerical example is given to determine the effectiveness of the proposed theory.

An Efficient and Green Approach for the Esterification of Aromatic Acids with Various Alcohols over H₃PO₄/TiO₂-ZrO₂

Kalbasi, Roozbeh Javad,Massah, Ahmad Reza,Barkhordari, Zeynab Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.8

$TiO_2-ZrO_2$ was prepared with surfactant through a sol-gel method. Catalysts containing 5 - 35% $H_3PO_4$ were prepared using these oxides. Subsequently the catalytic performance of prepared catalysts was determined for liquid phase esterification of aromatic acids. $H_3PO_4/TiO_2-ZrO_2$ has been used as catalyst to synthesize various novel esters by esterification of some aromatic acids with aliphatic alcohols (2-propanol, 1-butanol, iso butanol, 3-pentanol, 1-hexanol, heptanol, cyclo heptanol, octanol and decanol). Under optimized conditions, maximum yields and selectivity (100%) to the corresponding ester, was obtained by using 25 wt % $H_3PO_4/TiO_2-ZrO_2$ as catalyst. The Catalyst can be easily recycled after reaction and can be reused without any significant loss of activity/selectivity performance. No by-product formation, high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present synthetic protocol. The reaction was carried out under solvent-free condition.

An Efficient and Green Approach for the Esterification of Aromatic Acids with Various Alcohols over H3PO4/TiO2-ZrO2

Roozbeh Javad Kalbasi,Ahmad Reza Massah,Zeynab Barkhordari 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.8

TiO2-ZrO2 was prepared with surfactant through a sol-gel method. Catalysts containing 5 - 35% H3PO4 were prepared using these oxides. Subsequently the catalytic performance of prepared catalysts was determined for liquid phase esterification of aromatic acids. H3PO4/TiO2-ZrO2 has been used as catalyst to synthesize various novel esters by esterification of some aromatic acids with aliphatic alcohols (2-propanol, 1-butanol, iso butanol, 3-pentanol, 1-hexanol, heptanol,cyclo heptanol, octanol and decanol). Under optimized conditions, maximum yields and selectivity (100%) to the corresponding ester, was obtained by using 25 wt % H3PO4/TiO2-ZrO2 as catalyst. The Catalyst can be easily recycled after reaction and can be reused without any significant loss of activity/selectivity performance. No by-product formation,high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present synthetic protocol. The reaction was carried out under solvent-free condition.

A New Adaptive Importance Sampling Monte Carlo Method for Structural Reliability

Ehsan Jahani,Mohsen A. Shayanfar,Mohammad A. Barkhordari 대한토목학회 2013 KSCE Journal of Civil Engineering Vol.17 No.1

Monte Carlo simulation is a useful method for reliability analysis. But in Monte Carlo, a large number of simulations are required to assess small failure probabilities. Many methods, such as Importance sampling, have been proposed to reduce the computational time. In this paper, a new importance sampling Monte Carlo method is proposed that reduces the numbers of calculation of the limit state function. On the other hand, the proposed algorithm does not need the knowledge about the position of the design point or the shape of the limit state function. The key-idea of the proposed algorithm is that the mean of sampling density function is changed throughout the simulation. In fact, in random point generating process each point with lower absolute value of limit state function and nearer distance from space center is considered the mean of the sampling density function. Based on this, the centralization of the sampling will be on the important area.