In this article, an attempt has been made to estimate the amount of sound transmission loss in a flat oval channel by applying the approach of statistical energy analysis. Correct estimation of sound transmission loss in an air conditioning channel is of great importance due to the harmful effects of noise pollution in the environment on human health. Simulation with the statistical energy analysis method is a powerful approach to estimate sound and vibration in problems in which we deal with complex and multi-part systems; is considered. In this method, first, a system is divided into several subsystems, and then by writing a matrix equation that includes the energy exchanges between subsystems and energy loss coefficients; It is investigated from the perspective of vibration and sound estimation.On average, the model presented in this research is able to estimate the sound transmission loss in different dimensions of the air conditioning channels according to the experimental results in the accuracy range of ± 2.5 dB. Considering that it seems that the results obtained from modeling with this method are in good agreement with the experimental data; The results of this research can be used as an efficient approach to estimate noise in oval shaped channels stretched in different lengths.

The first part of this paper discusses the importance of porous materials in passive noise reduction, types of porous materials, various applications of these materials, relevant acoustical and non-acoustical parameters, and different methods to measure them based on international standards were explained. In this part of the paper, definitions and experimental methods used in measuring the acoustic properties of the absorption coefficient and the sound transmission loss based on international standards are presented. Then, while providing a comprehensive discussion of the sound absorption mechanisms in porous materials, the types of sound absorption mechanisms, including viscous, thermal, and structural losses, are described. The effect of different parameters on the variation of sound absorption of porous materials has been presented. Also, various models, including experimental, laboratory, and analytical models used for expressing the acoustical and mechanical properties of porous materials, are discussed. Finally, a brief review is present for recent research areas on porous materials.

In this study, it is assumed that the outer shell of the sandwich has a core made of functional calibrated materials with piezoelectric patches and the inner shell is made of layered composites. Double-walled cylindrical shells have three external, internal and middle acoustic environments and are exposed to acoustic waves with a specific angle of effect. The dynamic equations of the structure are derived using the hypothesis of first-order shear displacement field of shells and Hamilton principle and together with the fluid / structure boundary conditions form the final equations. Using the Fourier series expansions of the input, return, and output sound pressures and shell displacements, the dynamic equations are discretized to form a state matrix. After validating the results with existing articles, finally the effects, voltage applied by piezoelectric patches, percentage of functional materials, angle of fibers used in composites, types of composite materials, number of piezoelectric patches and angle of impact on the structure of sound transmission behavior It has been evaluated in a certain frequency range. Finally, the voltage parameters applied by the piezoelectric patches, the percentage of functional materials, the angle of the fibers used in the composites, the types of composite materials, the number of piezoelectric patches and the angle of impact increased the sound loss.

The purpose of this paper is mainly to discuss the nationality of Mowlana, ending with some remarks on the responsibilities of us Iranians about introducing Mowlana and other luminaries of the Iranian civilization. Mowlana's nationality could be discussed in terms of geography/ history and the message of his poetry. In the former case, there are facts which cannot be changed whether we like them or not. Mowlana consider himself as belonging to korasan, and the greater korasan used to be part of the greater Iran. From the pictures AflakI presents of the circle of Mowlana in Konia, one gets the impression that Mowlana had opened a branch of the cultural Korasan in Konia. But in terms of message, Mowlana is a voice that belongs more to any place that could be heard better, the voice of a man whose great Masnavi is the greatest spiritual epic man has produced, a gift granted by God to the Persian language to make the Persian culture immortal. To Mowlana, the question of nationality is so irrelevant, as is the question of belonging to this or the other world. He likens himself to the sun; if the walls separating houses and countries are removed, what remains is the light arising from the unified soul. As he states symbolically in the beginning of his great Masnavi, his country is the reed-bed, and it is his separation from the reed-bed that has given rise to all the tales and complaints.

Bazaars are among the few historical buildings that still continue to operate. The Bazaar in a city has been important not only from economic aspects but also from cultural and social aspects. Today, the empty space of such urban spaces, which can become a lasting space by creating a sense of belonging and peace, while meeting the needs of today's people, is felt very much. Sound is one of the main factors in creating memories in the human mind. In order to investigate the role of sound in the traditional architecture of Iran, a research was conducted in the Vakil Bazzar of Shiraz. The final goal of this research is to investigate the quantitative and qualitative conditions of the sound using sound meter software in the Vakil Bazzar of Shiraz. The permissible level of noise pollution in urban spaces is 60 decibels based on the resolution of the Supreme Council of Environmental Protection of Iran for commercial areas. The results of this research indicate that in the quietest conditions, the noise pollution for at least 33% of the Bazzar space is higher than the maximum allowed amount of noise pollution. How to improve the sound conditions in Vakil Bazzar, such as reducing noise by creating a masking sound source, creating a pond and a fountain, is one of the most important results of this research.

Low-frequency noise is annoying even at lower levels and affects cognitive functions of individuals. Some individual differences, such as sensitivity, can reduce or increase the effects of noise on cognitive performance. This study investigated the effect of noise sensitivity on cognitive performance in the presence of low-frequency noise. In this experimental study, 120 fourth-year seniors in the field of health sciences year from Hamadan University of Medical Sciences, Iran were selected through purposive sampling (60 students with high sensitivity and 60 students with low sensitivity). All the participants were exposed for 40 min to the noise levels of 50, 60, and 70 dB at the frequencies of 125 and 250 Hz, during which, the cognitive performance of the subjects was examined using the Integrative Visual-Auditory Continuous Performance Test (IVA CPT). Data were analyzed by independent t-test, and ANOVA test in SPSS 20. 0 software. The low-frequency noise negatively affected the components of cognitive performance so that with increasing the sound pressure level (SPL) from 50 to 70 dB and from 125 to 250 Hz (P<0. 05), the components of cognitive performance decreased. The results also showed that in female subjects with high sensitivity, cognitive performance components were more affected than the male subjects with low sensitivity (P<0. 05). The components of attention and work quality reduced with increasing SPL, and this negative effect of low-frequency noise was higher in women with high sensitivity.