مجله انجمن مهندسی صوتیات ایران
سال دوازدهم شماره 2 (پاییز و زمستان 1402)

Mapping and analyzing scientific outputs are valuable methods for examining studies in specialized fields. In this regard, the most appropriate way is to investigate indexed documents in scientific databases. This article aims to draw scientific maps and analyze published documents in acoustic cavitation, providing a quantitative evaluation of research outputs, identifying active researchers, and exploring related fields. The research community is the documents indexed in the Scopus database from the first until the time of doing the research (March 2023). Data analysis was performed using Excel and VOSviewer software. The findings reveal an increasing trend in scientific outputs related to acoustic cavitation until the time of the study. Among the 63277 records obtained, Iran ranks 17th in the world with 722 scientific documents. Generally, the Chinese Academy of Sciences and the Ministry of Education of the People's Republic of China were identified among the international institutions and/or universities, and Sharif University of Technology and Tarbiat Modares University as domestic active universities in acoustic cavitation. Engineering and Physics have the most scientific outputs in the field of acoustic cavitation. The keywords of this field in Mathematics can be classified into five main clusters according to the co-occurrence index.

In this study, ultrasound waves were used to destroy blood clots or thrombus by using ultrasound waves and creating acoustic cavitation, which is one of the non-thermal biological effects of these waves. Due to the fact that thrombosis leads to the blockage of blood vessels and is one of the most important causes of stroke and heart attack, in-vitro tests were performed on the blood clot tissue. Irradiation of ultrasound waves with different frequencies and intensities in variable time intervals, in the form of timed pulses, and uniform radiation, caused the cavitation phenomenon and the creation of gas microbubbles in the environment. After sonic pressure was applied to the bubbles and collapse occurred, the irradiated area was destroyed and the clot tissue slipped. Ultrasonic images and comparison of the irradiated samples with the reference model and the difference in the molecular structure of the tissue and clot walls with a microscope were used to confirm the results. Therefore, the results of this research confirmed that the proposed method can be used clinically as an alternative to non-invasive treatment to eliminate thrombosis.
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The emitted sound from ships is one of the most important sources of noise in the ocean, and the propeller sound is the main component of this sound. In this study, the numerical investigation of the functional sound level of a marine propeller has been carried out based on Computational Fluid Dynamics (CFD) and Fox Williams-Hawkings (FW-H) acoustic Analogy. In this research, in order to validate the solution method, first the fluid field around the DTMB4119 propeller was simulated, and then its sound pressure level compared with experimental results. Then the new propeller is numerically investigated. The acoustic performance of this propeller is evaluated in two permanent and non-permanent modes. First, a steady-state hydrodynamic simulation was created, and then the flow field is simulated by adopting the unsteady equations of Improved Delayed Detached Eddy Simulation (IDDES). According to the propeller diameter (D=2m), this simulation was done for the scale of the model, then ITTC87 equations are used to generalize the noise results to the actual size of the propeller. The sound level of the propeller is drawn at distances of 1 and 4 meters and at angles of 30, 60, 90, 120 and 150 degree and analyzed.

In this research, an attempt has been made to observe the seasonal changes of hydrophysical variables by using temperature and salinity data relative to depth during a 20-year statistical period in the Indian Ocean and calculating the sound speed profile. Using Mackenzie's formula, the speed of sound in the studied area has been calculated and analyzed. Seasonal changes in the sound profile of the Indian Ocean occur regularly throughout the year. These changes are mostly related to factors such as ocean currents, weather conditions and changes in water level. By drawing the profiles of these data, it can be seen that sea water has density stratification and seasonal and permanent temperature gradients and as a result, seasonal and permanent acoustic channels are formed in the deep ocean.

Continuous monitoring of river discharge is crucial for environmental, social, and economic evaluations in water resources management. River acoustic tomography is a system that uses the acoustic tomography method to improve the accuracy of flow measurements and solve the problems of discharge measurement methods. However, the collected data may contain outlier data, which can change the output results and measurement error if not identified and removed. In this research, modified singular spectrum analysis and hybrid kernel density method along with five replacement methods were used to identify and remove outliers. The replacement methods include linear interpolation, an average of outlier data, an average of unexamined outlier data, the replacement of outlier data with the last valid data before the outlier data, and the average of one point on each side of the outlier data. Out of 12232 data, 1076 data (about 9%) and 676 data (about 6%) of the total data were identified as outlier data using the modified singular spectrum analysis and kernel density method, respectively. According to the analyses and investigations, the modified singular spectrum analysis has performed better than the kernel density method.