Showing 3 results for Taban
Ehsan Rezaieyan, Ebrahim Taban, Seyyed Bagher Mortazavi, Ali Khavanin, Hasan Asilian, Elham Mahmoudi,
Volume 12, Issue 2 (6-2022)
Abstract
Introduction: Micro perforated panel (MPP) absorbents promise the next generation of sound absorbers as they have significant advantages over other porous adsorbents. In this study, we will investigate the acoustic performance of MPP absorbents made of biodegradable polylactic acid composite reinforced with natural corkwood fibers (PLA/Corkwood) by 3D printing technology.
Material and Methods: First, the effective dimensional characteristics of the parameters were determined, then, all of the samples were fabricated by the Zortrax M200 3D-Printer using the FDM method. The normal incidence sound absorption coefficient of the samples was measured using an acoustic impedance tube according to ISO 10534-2 in the frequency range of 64 to 1600 Hz. Then the effect of four geometric parameters, including hole diameter, panel thickness, perforation ratio, and air gap depth, on the absorption coefficient was studied.
Results: The findings show that the SL-MPP 12 absorbent has the highest average sound absorption coefficient (SACA) with a value of 0.28, so that at a frequency of 804 Hz it has the highest sound absorption equal to 0.91. The parametric study found that as the hole diameter increased, the values of peak adsorption and average absorption coefficient were decreased. Increasing the MPP thickness causes the absorption peak to move towards the lower frequency range. Decreasing the perforation ratio increases the peak absorption values and the average sound absorption, and the frequency with the highest absorption also moves towards the higher frequency range. The resonant frequency also depends on the depth of the air gap behind the screen. Changes in air gap depth from 30 mm to 70 mm reduced the resonant frequency by more than 35%.
Conclusion: Using 3D printing technology, sustainable MPP can be fabricated with more quality and in less time than traditional methods such as mixing and heat pressing.
Akbar Ahmadi Asour, Mohammadreza Monazzam, Ebrahim Taban, Zahra Hashemi, Somayeh Amininasab,
Volume 13, Issue 3 (9-2023)
Abstract
Introduction: The aim of this study was to investigate the effect of particle size (mesh) on the sound absorption coefficient of the absorbers made from Arundo Donax reed and to determine the optimal mesh for sound absorption.
Material and Methods: After crushing the reed stems in 10, 30, 20, 16, and 40 mesh sizes, they were washed with 5% NaOH. To make the samples 3 and 10 cm in diameter, 10% PVA was used as a binder, and the impedance of the two-channel tube was used according to ISO 10534-2 standard to determine the absorption coefficient. 22 samples of meshes 16 and 20 were made to achieve the optimal mesh based on the optimized RSM method, and the SAA index was used to compare the samples and determine the optimal mesh.
Results: The highest absorption peak was related to meshes 16 and 20 at the frequency of 2500 Hz, which is 0.94 and 0.98 ,respectively. The effect of increasing the thickness and density on the absorption coefficient is evident. The results have shown the effect of increasing the thickness and density on the absorption coefficient in mesh 20 in such a way that by increasing the density from 150 to 250 and the thickness from 10 to 30 mm, the absorption coefficient has increased from 35 to 63.5%. The optimal sample was mesh 20 with a thickness of 30 and a density of 250 kg/m3, which had the highest average absorption (SAA=0.57). The greater distance between the real and imaginary parts of the impedance shows the reactivity of the sample. In mesh 16 this distance is greater, as a result, mesh 16 has more reactivity and correspondingly less absorption.
Conclusion: The role of particle mesh as one of the important and influencing parameters on absorption coefficient has been investigated in this study.
Seyvan Sobhani, Mohammad Sharif Hosseini, Sara Tabanfar,
Volume 13, Issue 3 (9-2023)
Abstract
Introduction: Nurses’ high workload may affect their ability to work, cause health problems, and reduce nurses’ quality of life. Considering the important role of nurses in society’s health, it is important to identify the factors affecting their physical and mental health. The current study investigates and correlates nurses’ workload, quality of life, workability, and contextual variables.
Material and Methods: In this descriptive-analytical and cross-sectional study, 142 subjects from the ICU, CCU, emergency department, and other departments of Qazvin educational-therapeutic hospital participated. Data collection tools included a demographic information questionnaire, NASA-TLX (Task Load Index), Short Form Health Survey (SF-36), and work ability index (WAI). Data were analyzed with an independent t-test, Pearson’s correlation coefficient, and a one-way ANOVA test.
Results: The mean and standard deviation of nurses’ age and work experience were 31.3±6.1 and 7.6±5.8, respectively. The mean and standard deviation of nurses’ workload score, quality of life, and workability were 80.4±13.4, 55.5±18.7, and 31.8±7.3, respectively. According to the results, nurses’ workload had a significant relationship with quality of life (P-value=0.001) and workability (P-value=0.000). Significant relationships were also observed between quality of life and workability (P-value=0.001). Quality of life had a significant negative correlation with age, work experience, and the number of nurses’ shifts per month (P-value<0.05). Nurses with higher education had lower workload and higher workability.
Conclusion: Nurses working in ICU and CCU units had a higher workload. Nurses with higher education levels had less workload and more ability to work. There was an inverse correlation between workload quality of life and nurses’ workability. It is possible to reduce nurses’ workload by reducing their tasks and working hours.
