Investigating the effect of hot and cold polyurethane foam on reducing whole body vibration of forklift operators.

BACKGROUND: Vibration is one of the harmful factors for forklift drivers. The use of non- standard seats and not paying attention to how the seats are maintained can be affected by the amount of vibration transmitted to the person. OBJECTIVE: This study investigates the amount of vibration transmitted from the forklift and the effect of different types of polyurethane foam in reducing the vibration transmitted from the forklift seat. METHODS: This descriptive-analytical study was performed on 38 forklifts in 4 diesel models with the same weight class. The amount of vibration transmitted from forklift seats according to ISO2631 standard, taking into account the effect of various factors such as foam type (hot and cold), thickness (6-12 cm), load and year Function was measured. The amount of vibration caused by the forklift on the seat and under the seat was evaluated using ISO7096 standard. RESULTS: The average total vibration of the whole body in all foams in no-load mode is more than with load. The transmission vibration of cold polyurethane foam is less than that of hot polyurethane foam. With increasing thickness, the efficiency of cold polyurethane foam increases by 12 cm and in the loaded state 40.63% and in the unloaded state 49.58% in reducing the vibration transmitted to drivers. CONCLUSION: The results of this study show that cold foam has better effectiveness and efficiency than hot polyurethane foam. Also, the thicker the foam, the less vibration is transmitted to the driver.

Quantitative evaluation of chemical fume hoods performance by CO2 tracer gas.

BACKGROUND: Various chemical substances and carcinogens have been presented in medical sciences universities' educational and research laboratories. For this purpose a suitable ventilation system had to be implemented to ensure the correct operation of the hoods. OBJECTIVE: To evaluate the performance of laboratory chemical fume hoods of the University of Medical Sciences using a novel quantitative method. METHODS: In this study, 43 chemical fume hoods were investigated in the laboratories of the University of Medical Sciences. The technical specifications of the hoods and their compliance with the standard have been investigated. The hoods face velocity was measured using a thermal anemometer. Quantitative evaluation was performed using the new method of CO2 tracer gas and the results were analyzed using SPSS software version 19. FINDINGS: The hoods presented both favorable and unfavorable results in terms of technical specifications and location. The results showed 50.2% of the hoods have visible leakage. Hood face velocity was not suitable for any of the hoods in the case fully open.when half open only 16.3% of the hoods and in the case of 25% open face, 34.9% of the hoods had a good velocity. Most hoods have CO2 leakage even at small amounts. CONCLUSIONS: the unsuitable performance of the hoods is mainly due to the unsuitability of the fans, furthermore investigation and correction of technical problems are required. The new quantitative method is a suitable method for routine evaluating chemical fume hoods and can replace the SF6 gas tracer method.

Mental Workload and Job Satisfaction in Healthcare Workers: The Moderating Role of Job Control.

Objective: The aim of this study was to investigate the moderating role of job control in relation to mental workload and job satisfaction of healthcare workers. Methods: This cross-sectional study was carried out on 480 nurses, midwives, and administrative workers in four educational hospitals of Ardabil, Iran. Research tools were included demographic information questionnaire, NASA-TLX questionnaire, job description index (JDI) questionnaire and job control inquiry. Results: Compared with administrative workers, mental workload of nurses and midwives was significantly higher and likewise mental workload of nurses was significantly difference compared to midwives (P < 0.001). Nurses and midwives had substantially higher job satisfaction than administrative workers (P < 0.001). Also, nurses and midwives had higher job control than administrative workers (P < 0.001 and P = 0.002, respectively). Based on the designed model, the correlation between mental workload and job satisfaction was negative and significant (r = -0.22); which in the presence of job control, the relationship between the two variables of workload and job satisfaction slightly increased (r = -0.19, P < 0.001). These conditions were the same in the three job groups separately. Conclusion: Mental workload is inversely related to job satisfaction and job control. Job control plays an important role in improving working conditions in healthcare workers.

Ergonomics factors influencing school education during the COVID-19 pandemic: A literature review.

BACKGROUND: The school is one of the most critical social, educational, and training institutions and the main pillar of education in society. Education and, consequently, educational environments have the highest effect on the mentality, development, growth, welfare, concentration, performance, and learning efficiency of students. OBJECTIVES: The present study aimed to examine the effects of environmental ergonomics on the learning and cognition of pre-school students during the COVID-19 pandemic. METHODS: The study was carried out as a review article using some keywords, namely "children", "learning", "pre-school", "COVID-19", "ergonomics", and "environmental factors". Scopus, PubMed, Science Direct and Web of Science were searched to find related articles. RESULTS: Factors like color, form, and layout of classrooms, lighting and ventilation, interior decoration, and educational equipment are effective in creating interest and motivation for students to learn. CONCLUSIONS: A review of these articles showed that the presence of ergonomics in educational spaces for children increases the quality of learning and reduces stress and anxiety, and by observing health protocols, a healthy and safe environment can be provided for students.

The health effects of quarantine during the COVID-19 pandemic.

BACKGROUND: Quarantine is considered as an effective solution in the early stages of an epidemic. In the case of the coronavirus epidemic, quarantine was also recommended and implemented as a significant guideline to prevent the disease. However, despite the benefits of quarantine, there are also complications and problems. OBJECTIVE: The present study aimed to investigate the health effects of quarantine during the COVID-19 pandemic. METHODS: This study was conducted as a literature review through searching the databases Google Scholar, PubMed, and Science Direct for papers published before July 2020. The research was conducted based on the keywords "Coronavirus," "COVID-19," and "quarantine." The references of the papers were also reviewed to find the ones not found in the databases. The guidelines published by reputable organizations such as the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) were used in this study. RESULTS: Although quarantine is applied as an important and primary solution in the outbreak of epidemics, in cases of pandemics, it may not be free of negative effects on individuals and public health. However, because of the need to reopen and restart social and economic activities, some changes should be made in lifestyles and work activities. Using cyberspace and telework can be helpful. As the findings showed, COVID-19 bubbles can be used to restore social communications. CONCLUSION: Using masks, avoiding unnecessary gatherings, complying with personal and social hygiene, and respecting social distancing can be valuable solutions that, if implemented properly, can decrease the rate of the disease significantly. It is also emphasized that quarantine is still necessary and important as the best solution for sick people and individuals who are suspected carriers of the disease.