Mohammad Hajaghazadeh, Hossein Marvimilan, Fatemeh Farrokhi, Samira Orujlu,
Volume 6, Issue 2 (6-2016)
Abstract
Introduction: Safety climate is the perception of personnel about the priority of safety in an organization. The objective of this study was to evaluate safety climate using Nordic questionnaire in a hospital.
Material and Method: In this cross-sectional study, 92 nurses working in different wards of a hospital in uromia city, Iran, filled out the NOSACQ-50 questionnaire. The responses of nurses were recorded with a 4-point Likert scale. The results were analyzed using descriptive and analytical statistics.
Results: Seventy-two percent of nurses were female and the remainders (28%) were men. The mean score of safety climate dimensions was different. “Management safety priority, commitment, and competence” and “Safety communication, learning, and trust in co-workers safety competence” dimensions obtained the lowest and the highest scores by nurses, respectively. The mean score of safety climate ranged 2.49 to 2.67 in different wards of the hospital. What is more, the mean safety climate was not statistically differed among nurses of various age and work experience categories (P-value> 0.05).
Conclusion: According to the results, it can be noted that the level of safety climate in the hospital was fairly good from the nurses’ viewpoint. However, attempts should be made to improve it, especially in the safety management related dimensions. Corrective control measures should be implemented in all wards of the hospital for all personnel with any age and work experience.
Iraj Alimohammadi, Mahdi Farrokhi, Sevda Javadi, Mozhgan Nouraei, Leila Hosseini Shafeie,
Volume 15, Issue 1 (3-2025)
Abstract
Introduction: A significant contributor to noise pollution in urban areas is automobile exhaust systems, wherein mufflers, as passive devices, are designed to mitigate the noise produced. The dimensions, shape, and configuration of the muffler, along with its associated components and pipes, influence its effectiveness in sound transmission loss. This study investigates the impact of varying the length of the muffler’s connecting pipes and their associated holes on sound transmission loss in reactive mufflers, utilizing software simulation for analysis.
Material and Methods: The research utilized COMSOL 5.5 to simulate the effects of different geometric factors on sound transmission loss in mufflers. Modifying factors such as the length of connecting pipes and the existence of holes led to the development of various designs. Analysis of the results was conducted to assess the impact of each parameter on sound attenuation, enabling a straightforward comparison of acoustic efficiency.
Results: Studies demonstrate that changing the form of pipes at different frequencies produces diverse outcomes. Introducing a perforation prior to the tube and utilizing elongated connecting tubes with expansion chambers can enhance transmission attenuation. On the other hand, transmission loss decreases with longer pipes that lack holes. Lower pitches experience minimal attenuation, whereas higher pitches undergo more loss. Reactive mufflers work best at certain frequencies, where the length of the connecting pipe affects both the acoustic mass and the effectiveness of the muffler.
Conclusion: The results obtained from this study can inform the optimal design of mufflers aimed at enhancing their efficacy in sound transmission loss. Furthermore, it is essential to consider the synergistic impact of the geometrical configurations of the internal pipes within the muffler to minimize sound emissions from the exhaust outlet.
