Background: Proper designing of chairs based on ergonomics increases efficiency, promotes quality of education, leads to correct posture in students, and reduces risk of musculoskeletal disorders. Objectives: The aim of this study was to design and develop an ergonomic chair, based on anthropometric data of students in educational settings. Methods: Anthropometric parameters were obtained from a stratified-random sample of 207 students. The data were analyzed using the SPSS 20 software, and the results were extracted as mean, standard deviation, and percentiles. The chair was planned in the CATIA software and developed by a three-dimensional print. Results: In this study, an ergonomic chair was designed based on anthropometric data from students. The seat height, depth, and width of the chair were determined as 44 cm, 42 cm, and 42.15 cm, respectively. The height of the desk was adjustable in 19 to 29 cm, and the depth and length of the desk were considered as 51 cm and 65 cm. The width and height of the backrest were also 54 cm and 44 cm, and the backrest angle was adjustable in 95°to 105°. Conclusions: An ergonomic chair with adjustable parts was designed to achieve a well-match between anthropometric characteristics of students and the furniture. Such chair can reduce musculoskeletal disorders in students. Some ergonomic characteristics of this chair include adjustability of footrest, backrest, armrests, and desk. A chair with such characteristic can be used by many students with different body sizes.

Many studies of the photocatalytic oxidation process investigated on the removal efficiency and other variables of the input and output photoreactor. In the laboratory scale, it’s impossible, examination of the removal efficiency details, such as mass and energy transfer with air flow rate. Also, experimental methods request time consumption and money. For this reason, the simulation method can be used. The aim of this study was to prove that the validation of modeling approach in the photocatalytic oxidation process in the removal of toluene from air. Investigation of bed surface morphology, with FESEM, BET and TGA, shows acceptable monotonous of TiO2 nanoparticles on the ss plate. Furthermore, it was observed good adherence of nanoparticles on it. Experimental results on photocatalytic bed surface exhibited in the toluene concentration range of 10–40 ppm and flow rate of 2–5 l/min, with increasing flow and decreasing concentration, removal efficiency increased. The optimum removal point was 59% and 25 g/m3 min for 3.75 ppm and 5.61 l/min. For bed surface performance, the correlation between experimental results and simulation data was obtained 98%. According to the results, the photocatalytic oxidation process performed well for removal of low concentration of toluene from air. In addition, the obtained simulation method eliminated the random factors which can be affected by photocatalytic bed surface and it can show dependence of results based on reality.

The present study examines using photocatalytic reaction system along with TiO 2 particles coated on stainless steel webnet to study direct conversion of toluene using a new design. The study was carried out using UV radiation in a dynamic concentrator system. SEM and XRD analyses were performed to characterize prepared catalysts. Here, the aim was to employ photocatalytic oxidation (PCO) to optimize removal efficiency and elimination capacity using response surface methodology (RSM). To this end, initial concentration and flow rate were selected as independent variables. High removal efficiency and elimination capacity were realized using optimal settings. The findings indicated that PCO process with a new design other than RSM was an option to treat air pollution containing volatile organic compounds.

Abstract:The hydrolysis reaction of Methyl Tert-Butyl Ether (MTBE) into biodegradable products was studied on as-synthesized and commercial H-MFI zeolites. The effect of synthesis procedure and SiO 2 /Al 2 O 3 ratio was investigated. The results obtained were indicated that H-MFI zeolites were effective in MTBE hydrolysis and increasing of the Si/Al ratio promotes the hydrolysis reaction. The amount of produced TBA was always lower than what expected estoichiometericaly. It is concluded that the missing amount of TBA can be a result of possible formation of an alkene. The capability of indigenous microorganism to biodegrade hydrolysis products in presence of zeolite was also studied. Microorganism was able to use products except TBA produced intermediate carbocation hasn't any adverse effects on the microbial activity.

Introduction: Hearing loss is one of the most common causes of disability of more than 1.33 billion people worldwide and, according to WHO research, failure to timely detect hearing loss has detrimental effects on the individual, the family and the world economy ($ 750 billion), Therefore, exposure to excessive noise and exposure to organic solvents can cause hearing loss in individuals. Methods: This descriptive-analytical study was performed on a manufacturing company with a statistical population of 17 people (8 employees of printing and electroplating unit with a mean age of 40±4.78 and 9 employees of Coldwell unit with a mean age of 4.33±41). Data were analyzed by SPSS software version 16 and paired T-test. Results: According to the pollutant results in the Coldwell unit, the noise level was exceeded, but the toluene levels were measured at the permissible level, which, according to the software output, showed a faster rate of hearing loss (Right ear sig = 0.007 and left ear sig = 0.002) and also, in the printing and plating unit, the sound level was above the permissible limit, but the toluene level was exceeded, which according to the software output of these units had a lower rate of hearing loss. Conclusion: The results of this study show that simultaneous exposure to noise and organic solvents such as toluene in the workplace accelerates the Occupational Hearing Loss Process, as well as employees who are not exposed to noise, are reasonably hearing impaired due to exposure to toluene.   keywords: Noise, Audiometry, Occupational Hearing Loss, Measurement of Workplace Hazardous Factors, Organic Solvent Vapor, Toluene Vapor.