Evaluation of soil-tire interaction on a soil bin

A single wheel tester with the attention to the size of soil bin has been designed and fabricated to study soil tire interactions, in controlled soil environment.  The main parts of a single wheel tester include chassis, reduction gear unit, three-phase AC electric motor, hydraulic cylinder, tank, pump and valve, load cell and tires.  The experiment was designed with two levels of tire axle loads (15 and 25 kN) and two inflation pressures (70 and 150 kPa).  The tire (18.4/15-30) was run at a constant forward speed of 0.3 m s-1, 13% slip and 12% moisture content(d.b.) on clay loam soil.  A statistical comparison was made for the cone index values measured in the undisturbed soil, at the center of the track, and at the edge of the track.  A significant difference in cone index was found for all treatments.  Inflation pressure at the center and load at the edge of tire track has significant effect on cone index and dry bulk density.   Keywords: cone index, inflation pressure, load; dry bulk density, soil bi

Psychometric Properties of the Persian Version of Consideration of Future Safety Consequence (CFSC) Scale

Background: Personality traits, due to having a relative stability, are important factors for predicting employees’ safety behavior. Consideration of Future Safety Consequence (CFSC) is a personality trait that was recently introduced to predict the safety behaviors. The purpose of this study was to translate and assess the psychometric properties of the Persian version of the CFSC scale. Methods: In the first stage of this cross-sectional study, the instrument was prepared by the forward-backward forward translation technique and evaluated by 487 employees of a gas refinery. The validity of the scale was evaluated through face, concurrent, validity, and construct validity. The safety performance questionnaire was used to examine the concurrent validity. The reliability of the questionnaire was evaluated using internal consistency (Cronbach’s alpha coefficient) and test-retest. Results: Content validity index was 0.885. The results of exploratory and confirmatory factor analysis indicated that the CFSC scale had a single factor. Also, Pearson correlation showed a positive correlation between the safety performance and the Persian version of CFSC (R=0.401). Test-retest reliability and internal consistency were calculated as 0.86 and 0.82, respectively. Conclusion: It is concluded that the psychometric properties of the Persian version of CFSC scale are desirable and can be used in future studie

Occupational Stressors Among Firefighters: Application of Multi-Criteria Decision Making (MCDM)Techniques

Background: Firefighters are exposed to a wide range of occupational stressors due to the nature of their job. Multicriteria decision-making technique (MCDM) is a method for identifying, evaluating, and preventing occupational stressors among firefighters. The purpose of this study was to identify and prioritize the occupational stressors among firefighters using the fuzzy delphi method (FDM) and fuzzy analytical hierarchy process (FAHP). Methods: This qualitative-descriptive study was carried out in two stages. First, the most important occupational stressors of firefighters were identified and screened using a systematic review of scientific references and expert opinions based on the FDM. Then, all of the screened stressors were weighted and prioritized by the FAHP using the opinions of experts. All results were analyzed using Excel software. Results: Among, the 52 occupational stressors of firefighters identified in the first stage, 27 stressors were selected to enter into the FAHP. The FAHP results showed that among the four main dimensions, the weight of managerial factors (0.358) was more than other dimensions. The overall result of the study, regardless of the stressors’ main dimensions showed that the most important stressors among firefighters were financial strain due to inadequate pay, fear of explosion at incident scenes, toxic smoke, and gases produced at fires and lack of attention given to job safety by management, respectively. Conclusion: According to the results of the study, most occupational stressors of the firefighters are caused by organizational factors. Therefore, the implementation of management strategies to reduce the occupational stress of firefighters is recommended

Factors influencing nurses' acceptance of hospital information systems in Iran: application of the Unified Theory of Acceptance and Use of Technology

Abstract User acceptance is a precondition for successful implementation of hospital information systems (HISs). Increasing investment in information technology by healthcare organisations internationally has made user acceptance an important issue in technology implementation and management. Despite the increased focus on hospital information systems, there continues to be user resistance. The present study aimed to investigate the factors affecting hospital information systems nurse-user acceptance of HISs, based on the Unified Theory of Acceptance and Use of Technology (UTAUT), in the Shiraz University of Medical Sciences teaching hospitals. A descriptive-analytical research design was employed to study nurses' adoption and use of HISs. Data collection was undertaken using a cross-sectional survey of nurses (n=303). The research model was examined using the LISREL path confirmatory modeling. The results demonstrated that the nurses' behavioural intention (BI) to use hospital information systems was predicted by Performance Expectancy (PE) (β= 2.34, p<0.01), Effort Expectancy (EE) (β= 2.21, p<0.01), Social Influence (SI) (β= 2.63, p<0.01) and Facilitating Conditions (FC) (β= 2.84, p<0.01). The effects of these antecedents of BI explained 72.8% of the variance in nurses' intention to use hospital information systems (R 2 = 0.728). Application of the research model suggested that nurses' acceptance of HISs was influenced by performance expectancy, effort expectancy, social influence and facilitating conditions, with performance expectancy having the strongest effect on user intention

Callus and somatic embryo induction in date palm cv. Khazravi using leaves, immature fruit and endosperm explants

The purpose of this study was to check the possibility of callus and somatic embryogenesis in date palm cv. Khazravi using different explants including leaves, green fruit, immature seed, endosperm and green fruit pericarp. In the culture of leaves in the medium contains different plant growth regulators including 2,4-D, BAP and TDZ, highest callus induction was achieved in medium supplemented with, 5 mg.L-1 2,4-D, 2 mg.L-1 BAP and 4 mg.L-1 TDZ, and in treatment with 5 mg.L-1 2,4-D, 1 mg.L-1 BAP and 4 mg.L-1 TDZ. By using explant of immature fruit, found that when two growths regulative, TDZ and 2, 4-D in amount of 5 mg.L-1 are in the culture medium callugenesis and embryogenesis was achieved. The endosperm cultivation with pericarp and embryo in the same medium showed that the presence of two growth regulators 2,4-D and TDZ have been useful for callus production. Also in endosperm with zygotic embryo culture, embryo development and the root and shoot were formed after three months. Endosperm culture, in the culture medium containing various auxins and pericarp culture showed no any reactions. In general, these results showed that in date palm cv. Khazravi, treating the explants of leave and immature fruits with appropriate concentrations of plant growth regulators auxin and cytokinin, can induce callus and embryo

Factors Affecting Resistance to Change among Hospital Staff using a Structural Equation Modeling Technique

Introduction: Hospitals are complex organizations faced with continuous fundamental changes complicated by expertise diversity. The aim of this study was to investigate the factors influencing hospital employees’ resistance to change. Methods: This cross-sectional study included 510 employees working in hospitals affiliated to Shiraz University of Medical Sciences; they were selected using stratified random sampling. Data were collected through a questionnaire. A structural equation modeling technique using LISREL Version 8.8 tested the hypotheses and conceptual model. Results: Results indicated that dispositional resistance to change and involvement with change directly affected the employees’ resistance to change. Perceived benefits of change to involvement in change were significant (T-values >1.96) and the hypotheses related to these paths were accepted. Perceived benefits of change indirectly affected the employees’ resistance to change by influencing involvement. Dispositional resistance to change and involvement in change (mediator variables) were estimated 0.89, 0.03, and 0.47, respectively. Conclusion: The study results indicated that hospital managers should encourage the employees to actively participate in their change program by strengthening perception of the benefits. This could help reduce the employees’ resistance

Statistical Analysis of Shunt-FACTS Devices Impact on Power Flow Control

Abstract: In this study, impact of Static VAr Compensator (SVC) on power flow control is studied by statistical indices. For this purpose, several conventional branches of SVC are introduced and their impacts are discuses on active and reactive powers flow control on power systems. Peak and least values used as decision criteria. To compare and discuss the capability of compared SVCs, two statistical indices are used; i.e. Absolute Percentage Error (APE) and Symmetric Mean Absolute Percentage Error (SMAPE). These indices help to result in analysis and extract novel aspect of behavior of SVCs. Simulations have been carried out in MATLAB/SIMULINK environment. In this study, first a general review on lectures about SVC has been done which has four parts; i.e. design, placement, application and modeling, respectively. Then, the most useful branch is chosen

Prediction of the tractor tire contact area, contact volume and rolling resistance using regression model and artificial neural network

A novel method to estimate the contact area and contact volume was developed with molding the tire footprint by liquid plaster and converting these molds to three-dimensional models using a 3D scanner. A 12.4-28, 6 ply tractor tire was operated under three levels of vertical load, three levels of inflation pressure and three levels of soil moisture content. To analyses the obtained data regression and Artificial Neural Network (ANN) models were used and the accuracy of predicted results were compared with measured data. A multi-layer perceptron feed-forward ANN with back propagation (BP) learning algorithm was employed. Two hidden layers were used in network architecture and the best number of neuron for each hidden layer was selected with attention to minimum RMSE criterion. The results showed that tire contact volume is a better parameter than tire contact area to predict rolling resistance. The comparison of the results of regression and ANN models to predict the contact area, contact volume and rolling resistance showed that ANN predictions had a closer agreement with the measured data than the regression model predictions

Development of a Discrete Event Simulation Model to Minimize the Waiting Time of Patients in Hospitals

Introduction: Proper management of health systems requires the use of a suitable decision making logic. Simulation is a good tool for accurate and evidence-based decision making. The main objective of this study was to developing a simulation model to minimize the waiting time of patients in the cardiac subspecality clinic of Kowsar Hospital. Methods: This is a cross-sectional study. The statistical population consisted of 576 patients, referring to Kowsar cardiac clinic in the morning and afternoon shifts. Data collection was conducted according to a designed timetable form. Scenarios were defined to receive the best answer. These scenarios were as follows: scenario A: decrease of the average of the service time; scenario B: increase of the mean time between the two entries; and scenario C: decrease of the service time and increase of the time between two entries. ARENA software was used to simulate and review the scenarios and General Algebraic Modeling System (GAMS) software was used to obtain a definite answer. Results: Simulation results showed that in scenario A the mean time spent in the system was 85.55 minutes in the morning and 77.05 minutes in the evening shifts. In scenario B, the average time spent in the system was 65.95 minutes in the morning and 79.63 in the evening shifts. In scenario C, the mean time spent in the system was 73.90 minutes in the morning and 61.17 minutes in the evening shifts. The result of the final model showed that the average time spent in the system was 97.33 min in the morning and 86.85 min in the evening. Conclusion: According to the results obtained from the use of the definitive and simulated models, it was found that the simulation model, due to its probability, faces a percentage of error. Comparison of the definitive and simulated models revealed that the best scenario to the definitive answer was scenario B (increasing the mean time between the two logs)

Occupational stress among nurses and pre-hospital emergency staff

Healthcare professionals, especially nurses and pre-hospital emergency (PHE) staff, are influenced by many stressors due to their responsibility to provide comfort as well as care and treatment of patients. The aim of the present study was to identify and rank the occupational stressors in nurses and PHE staff using Fuzzy Analytic Hierarchy Process (FAHP) method. In this cross-sectional study, occupational stress factors in nurses and PHE staffs were identified and ranked by 30 experts, using FAHP method. Occupational stress factors were collected by General Health Questionnaire (GHQ), Job Stress Questionnaires as well as a literature review. Among the occupational stress factors in nurses, the highest scores were related to “Incompatibility between work schedule and life conditions” (0.03986) and “Being criticized by supervisors” (0.03723), respectively. The most common stress factors in PHE staff were related to “Care of patients with critical health conditions” (0.07258), “High number of missions” (0.07056), respectively. The overall results of this study showed that managerial factors and factors related to patient care are the most important causes of occupational stress among nurses and PHE staff. These factors should be considered in the implementation of control strategies for reducing and managing occupational stress