Development and Validation of a Safety Climate Scale for Manufacturing Industry

Ghahramani, Abolfazl,Khalkhali, Hamid R. Occupational Safety and Health Research Institute 2015 Safety and health at work Vol.6 No.2

Background: This paper describes the development of a scale for measuring safety climate. Methods: This study was conducted in six manufacturing companies in Iran. The scale developed through conducting a literature review about the safety climate and constructing a question pool. The number of items was reduced to 71 after performing a screening process. Results: The result of content validity analysis showed that 59 items had excellent item content validity index (${\geq}0.78$) and content validity ratio (> 0.38). The exploratory factor analysis resulted in eight safety climate dimensions. The reliability value for the final 45-item scale was 0.96. The result of confirmatory factor analysis showed that the safety climate model is satisfactory. Conclusion: This study produced a valid and reliable scale for measuring safety climate in manufacturing companies.

The relationship between emotional intelligence and happiness in medical students

Sulmaz Ghahramani,AliReza Torabi Jahromi,Danial Khoshsoroor,Reza Seifooripour,Minoo Sepehrpoor 한국의학교육학회 2019 Korean journal of medical education Vol.31 No.1

Purpose: Emotional intelligence is a factor affecting the health of individuals, and happiness is another factor affecting it. Medical students’ health can greatly affect a community’s health due to the important role of medical students in maintaining and improving it. Accordingly, we aimed to study the relationship between emotional intelligence and happiness among the students of the Shiraz Medical School. Methods: This study is an analytical, cross-sectional study. The target population of this study was the medical students who began studying in the medical school and the international branch of Shiraz University of Medical Sciences from September 2014 to September 2017. The sample size was 300 students who were selected by a systematic sampling method. The instruments for collecting information in this study were Oxford Happiness Inventory and Siberia Schering’s Emotional Intelligence Questionnaire. The significance level of the tests was set at 0.05. Results: The mean age of 292 responded participants were 20.73 with standard deviation of ±1.81 emotional intelligence (p<0.001), level of stress (p<0.001), and grade (p=0.03) and type of personality (p<0.001) can explain the changes in the happiness level and they were significant effective factors in the regression modeling. Conclusion: Emotional intelligence was a predictive factor for happiness in medical students. Students with higher emotional intelligence felt healthier. And happiness in extroverted students was higher than introverted ones. It is suggested that the results of this study should be confirmed with prospective studies.

Development and Validation of a Safety Climate Scale for Manufacturing Industry

Abolfazl Ghahramani,Hamid R. Khalkhali 한국산업안전보건공단 산업안전보건연구원 2015 Safety and health at work Vol.6 No.2

Background: This paper describes the development of a scale for measuring safety climate. Methods: This study was conducted in six manufacturing companies in Iran. The scale developed through conducting a literature review about the safety climate and constructing a question pool. The number of items was reduced to 71 after performing a screening process. Results: The result of content validity analysis showed that 59 items had excellent item content validity index (? 0.78) and content validity ratio (> 0.38). The exploratory factor analysis resulted in eight safety climate dimensions. The reliability value for the final 45-item scale was 0.96. The result of confirmatory factor analysis showed that the safety climate model is satisfactory. Conclusion: This study produced a valid and reliable scale for measuring safety climate in manufacturing companies.

Synthesis and Morphology of Polyacrylate-Poly(dimethyl siloxane) Block Copolymers for Membrane Application

Mohammad Ali Semsarzadeh,Maral Ghahramani 한국고분자학회 2015 Macromolecular Research Vol.23 No.10

Poly(methyl acrylate)-poly(dimethyl siloxane)-poly(methyl acrylate) (PMA-PDMS-PMA) and poly(methyl methacrylate)-poly(dimethyl siloxane)-poly(methyl methacrylate) (PMMA-PDMS-PMMA) triblock copolymers were synthesized with atom transfer radical polymerization technique. Thermodynamic properties of block copolymer solutions were investigated. Solubility parameter differences and Flory-Huggins interaction parameters of block copolymer-solvent systems were evaluated for the membrane application. Morphology study indicated cylindrical micelles of PDMS block copolymers. X-Ray analysis confirmed phase separated morphology of PDMS block copolymers in bulk. The effect of polyvinyl acetate (PVAc) on the morphology and its effect on the gas permeation behavior of PMA-PDMS-PMA triblock copolymer was studied. PMA-PDMS-PMA/PVAc blend membranes were shown a new fibrillar morphology. The gas permeation properties and selectivity of the blend membranes were also reported.

Stress Level Based Bearing Capacity of Foundations: Verification of Results with 131 Case Studies

M. Veiskarami,M. Jahanandish,A. Ghahramani 대한토목학회 2012 KSCE Journal of Civil Engineering Vol.16 No.5

Evidence of decreasing magnitude in the bearing capacity factor, Nγ , in shallow foundations requires a different strategy rather than taking a constant soil friction angle conventionally used in computation of this factor. Because of the influence of stress level on soil friction angle, a more complex analysis may be required to compute the values of Nγ since the mobilized soil friction angle at failure differs from point to point beneath shallow foundations corresponding to the experienced level of stress. This can be performed by taking a variable field of mobilized soil maximum friction angle which can be achieved by the aid of the Zero Extension Lines (ZEL)equations. It has been realized by the authors in developing design charts in which, variations of Nγ with foundation size have been presented by the stress level based ZEL method. Following previous attempts, this research is devoted to extending these charts to circular foundations and furthermore, to provide an in depth investigation of the possibilities and advantages of using these charts. A comprehensive foundation load test database has been collected and recompiled for this research to compare the predictions made by the ZEL method in the suggested design charts with field data. The predictions by these design charts show a reasonable coverage over the entire range of selected case studies presented in this research.

Outlier Robust Learning Algorithm for Gaussian Process Classification

김현철(Hyun-Chul Kim),Zoubin Ghahramani 한국정보과학회 2007 한국정보과학회 학술발표논문집 Vol.34 No.2C

Gaussian process classifiers (GPCs) are fully statistical kernel classification models which have a latent function with Gaussian process prior. Recently, EP approximation method has been proposed to infer the posterior over the latent function. It can have a special hyperparameter which can treat outliers potentially. In this paper, we propose the outlier robust algorithm which alternates EP and the hyperparameter updating until convergence. We also show its usefulness with the simulation results.

Computational fluid dynamics modeling of high temperature air combustion in an heat recovery steam generator boiler

Abhas Khoshhal,Masoud Rahimi,Afshar Ghahramani,Ammar Abdulaziz Alsairafi 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.5

This paper reports a numerical study on the possibility of using high temperature air combustion (HiTAC)technique in the heat recovery steam generator (HRSG) boiler of the Fajr Petrochemical Complex, Iran. For this purpose a theoretical fuel nozzle which operates in HiTAC mode of combustion has been installed and modeled using the computational fluid dynamics (CFD) technique. By aim of establishing an efficient heat transfer rate to the boiler’s tubes, the proper nozzle location and an optimum mass flow rate of fuel have been found. The results show that by using this modification it is possible to increase the steam temperature up to 37 percent.

Fracture resistance of endodontically treated maxillary premolars restored by silorane-based composite with or without fiber or nano-ionomer

Shafiei, Fereshteh,Tavangar, Maryam Sadat,Ghahramani, Yasamin,Fattah, Zahra The Korean Academy of Prosthodonitics 2014 The Journal of Advanced Prosthodontics Vol.6 No.3

PURPOSE. This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane-or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS. Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate-and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (${\alpha}$=0.05). RESULTS. Mean fracture resistance for the eight groups (in Newton) were G1: $1200{\pm}169^a$, G2: $360{\pm}93^b$, G3: $632{\pm}196^c$, G4: $692{\pm}195^c$, G5: $917{\pm}159^d$, G6: $1013{\pm}125^{ad}$, G7: $959{\pm}148^d$, G8: $947{\pm}105^d$ (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION. Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

Effect of Stress Level on the Bearing Capacity Factor, Nγ , by the ZEL Method

M. Jahanandish,M. Veiskarami,A. Ghahramani 대한토목학회 2010 KSCE Journal of Civil Engineering Vol.14 No.5

It has been known that soil shear strength parameters are stress level dependent. On the other hand, foundation size has a significant effect on the level of imposed stress on subsoil elements. In this study, the Zero Extension Lines (ZEL) method, which has wide applications in determination of bearing capacity and load-displacement behavior of foundations and retaining walls, is employed to consider the stress level dependent nature of soil shear strength parameters to predict the actual bearing capacity of foundations. The ZEL equations which are capable of considering variations in soil shear strength parameters have been employed to consider their dependency on stress level and solved numerically by a computer code developed for this study. The presented approach has been compared with experimental data showing reasonable predictions when the effect of stress level is taken into account. It is then utilized to develop some design charts showing modified values of Nγ , as a function of foundation size and soil properties based on Bolton (1986) equation for stress level effect in cases of smooth and rough base foundations. The charts represent the decreasing tendency in Nγ with an increase in foundation size and it shows the decreasing tendency in the reduction rate when the foundation size increases.

Fracture resistance of endodontically treated maxillary premolars restored by silorane-based composite with or without fiber or nano-ionomer

Fereshteh Shafiei,Maryam Sadat Tavangar,Yasamin Ghahramani,Zahra Fattah 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.3

PURPOSE This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane- or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate- and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (α=0.05). RESULTS Mean fracture resistance for the eight groups (in Newton) were G1: 1200 ± 169a, G2: 360 ± 93b, G3: 632 ± 196c, G4: 692 ± 195c, G5: 917 ± 159d, G6: 1013 ± 125ad, G7: 959 ± 148d, G8: 947 ± 105d (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.