Journal of Health and Safety at Work

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Introduction: In Laboratory accusations a wide range of hand-held tools are used due to nature of their work. Long-term and repeated use of these tools has led the laboratory workers to suffer from upper limb disorders. The present study was designed and implemented with the aim of investigating the usability of different models of pipettes used in the laboratories of the Tehran University of Medical Sciences, employing subjective assessment methods for selecting the best pipette models.

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Material and Method: This cross-sectional and analytical-descriptive study was performed among 35 laboratories employees of Tehran University of Medical Sciences. First, four models of the widely used pipettes were selected and their usability-related characteristics were investigated by a visual analog scale (VAS). Judgments concerned the usability of the pipettes done based on the criteria provided by the International Organization for Standardization 9241-11(1998) and 20282-2(2006). Data analysis was performed, using SPSS software version 22.

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Result: The overall evaluation of the users in relation to the characteristics of the pipettes indicated that the highest VAS score was belonged to pipette A, C, and D, respectively. Furthermore, pipette B was selected as the most undesirable one by users. Results related to the usability criteria of pipette showed that of the four models of study pipettes, pipette A has been ranked first in two criteria (satisfaction and effectiveness). Regarding the efficiency, the first rank was for C pipette and the second rank was for pipette A. Pipette B obtained the lowest scores for all given criteria.

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Conclusion: Shorter and lighter pipettes, which were designed according to ergonomic principles, had greater usability from the perspective of users and it could cause a better subjective assessment comparing to the other models.

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Introduction: One of the most common pollutants in industrial and confined environments is toluene. Toluene can be removed in various ways. The simultaneous and integrated use of two methods—adsorption and photocatalytic degradation—in a single process is an important innovation in the removal of gaseous toluene. The aim of this study is to determine the efficiency of a synthesized reduced graphene oxide/carbon nanotube/titanium dioxide (RGO/CNT/TiO2) nanocomposite aerogel in the photocatalytic degradation and adsorption of toluene vapors. 
Material and Methods: In this study, RGO/CNT/TiO2 and RGO/TiO2 aerogels were prepared using a one-pot hydrothermal self-assembly method. The properties of the photocatalytic aerogels were investigated using BET testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). Aerogels were loaded on a substrate in a photoreactor with two UV-C lamps using dynamic flow. Adsorption efficiency was measured when irradiation was off, and photocatalytic degradation efficiency was measured when irradiation was on using an instantaneous reading device.
Results: Adding CNTs to RGO/TiO2 affects the specific surface area (SSA) and the porous structure of the aerogels. During the processes of adsorption and photocatalytic degradation using RGO/CNT%5/TiO2, the concentration of toluene vapor pollutant decreased from 20 ppm to 3.4 ppm, indicating an efficiency of 81%. In contrast, RGO/TiO2 demonstrated an efficiency of 43.41%.
Conclusion: The results demonstrated that adding CNTs to RGO/TiO2 aerogel significantly improves photocatalytic performance for the degradation of toluene vapor. This enhanced performance is attributed to increased light absorption, an improved electron and hole recombination rate, as well as the facilitation of electron transition from titanium nanoparticles to the graphene structure.