per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2019-03 6 2 1 8 article A. Adelnia akbar.adelnia@yahoo.com 1 M. Mokhtari-Dizaji mokhtarm@modares.ac.ir 2 S. Hoseinkhani saman_h@modares.ac.ir 3 M. Bakhshandeh mbakhshandeh@sbmu.ac.ir 4 Tarbiat Modares University Tarbiat Modares University Tarbiat Modares University Shahid Beheshty University of Medical Sciences In this study, the effect of single and dual-frequency sonication on cell death of B16-F10 melanoma cells is investigated at constant temperature. Here, 20 groups were studied. The test groups consisted of: control and sham, 40 kHz (intensity: 0.24 W/cm2), 1 MHZ (intensity: 0.5 W/cm2) and the dual frequency groups which each frequency group included seven subgroups of 30, 120, 60, 150, 300, 600 and 1200 s. Cell viability was measured by MTT assay. The result demonstrated that the cell viability for 40 kHz with 30 s sonication time was 96%, which decreased to 6% by increasing the sonication time up to 1200 s. In dual frequency, cell viability decreased in all subgroups, and its amount ranges from 95% at a sonication time of 30 s to 3% at 1200 s sonication time. The same process happens for 1 MHz frequency with a lower relative slope (97% to 15% when sonication time increased from 30 s 1200 s). Ultrasound waves caused the B16-F10 melanoma cell death in constant temperature. Dual frequency sonication caused more cell death especially at higher sonication time, possibly due to cavitation. http://joasi.ir/article-1-139-en.pdf Ultrasonic wave Dual frequency sonication B16-F10 melanoma cell Cell death ultrasound. per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2019-03 6 2 9 20 article F. Zahedi Salangooch f.zahedi91@yahoo.com 1 M.R. Housaindokht housain@um.ac.ir 2 R. Jalal azieh@um.ac.ir 3 A. Nakhaeipour a.nakhaei@um.ac.ir 4 R. Izadi Najafabadi izadi@um.ac.ir 5 In this study, the effect of low-frequency ultrasound on the structure and activity of urease enzyme has been investigated. For this purpose, the enzyme was exposed to ultrasound with 20 kHz frequency at different time intervals. The urease enzyme was immobilized on the surface of magnetic nanoparticles (Fe2O3), and activated silica gel with 89% and 66% efficiency respectively. The enzyme activity, kinetic parameters, optimum pH and temperature were determined for free and immobilized enzymes at different conditions. The structure change of free enzymes caused by ultrasound was vreified by fluorescence and UV spectrum. The activity of enzyme was amplified in the presence of ultrasound. A reduction in the activity and Vmax and an increase in Km were observed for both free and immobilized enzymes on the activated silica gel after ultrasound treatment. While, ultrasound had no effect on the immobilized enzymes on the magnetic nanoparticles. http://joasi.ir/article-1-122-en.pdf Urease Ultrasound wave Enzyme immobilization Fe2O3 magnetic nanoparticle Silica gel. per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2019-03 6 2 21 28 article M.R. Khalilabadi rezakhalilabadi@gmail.com 1 H. Shahmirzaeei Shahmirzaee@mut.ac.ir 2 Malek-Ashtar University of Technology Malek Ashtar University of Technology Porous materials have good acoustic damping characteristics over a wide frequency range. As for sound waves, many small-scale pores in the coating materials can convert underwater-coating to rough surfaces. The main property of porous absorbents is their resistance against incident sound wave that leads to damping effect. From a physical point of view, damping occurs due to friction between fluid molecules inside the cavity and absorbent structure. In this study, the acoustic properties of porous absorbents with different porosity levels have been evaluated using different mathematical models. These models use one or more parameters of materials for calculating acoustic characteristics. In all of these models, materials are considered as equivalent fluid and reactionary characteristics have not been into account.   http://joasi.ir/article-1-87-en.pdf Sound absorption Porous absorbent Porosity Acoustic characteristic. per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2019-03 6 2 29 38 article M. Bahreinimotlagh m.bahreini@wri.ac.ir 1 R. Roozbahani rezaroozbahani@gmail.com 2 M. Eftekhari 3 M.J. Zareian mj_zareian@yahoo.com 4 A. Farokhnia ashkan_farokhnia@yahoo.com 5 Water research Institute Water research Institute Water research Institute Water Research Institute Water research Institute Underwater acoustics is widely used in many applications, such as oceanography, marine biology, hydrography, fishery, etc. Different models are introduced to simulate the underwater acoustic propagation in the oceans and the seas. In this study, the Ray Theory model is used to simulate the acoustic wave propagation in a shallow-freshwater river (Gono River) located in western part of Japan. The Fluvial Acoustic Tomography System (FATS) evaluated the accuracy of the model estimations. The vertical sound speed profiles were measured by a CTD in the five positions and they were used as the model inputs. The simulation results showed two main groups of acoustic waves that propagated in different paths. The reasons were because of the riverbed topography and the flow velocity. Whilst, in the sea and the ocean, the temperature/salinity gradient and the existence of internal waves are the reasons of the acoustic propagation in different paths. The lag time between the arrival time of two ray groups was 0.5 msec. The FATS transducers were deployed on both sides of the river, where, the transmission length was set to 294.629 m and the central acoustic frequency was set to 30 kHz. Finally, the FATS measurements confirmed the model results.   http://joasi.ir/article-1-123-en.pdf Underwater acoustic wave propagation Ray theory Shallow-freshwater river FATS. per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2019-03 6 2 39 45 article A. Ghasemi Yeklangi akbarghasemi2@gmail.com 1 S. Esmaeelzadeh Khadem khadem@modares.ac.ir 2 Trabiat Modares University Trabiat Modares University Transparent acoustic sensors and actuators are a new generation of acoustic transducers that can create an evolution in the microphone and loudspeakers industries. These transducers with properties like transparency, flexibility, flatness, very low weight and thickness have a great potential for various applications like public speakers, active noise cancelation systems, displays, cell phones and hidden microphones. In this investigation, fabrication of a prototype of these transparent transducers was the goal. In this research with coating multi wall carbon nanotube on PVDF substrate, a transparent acoustic sensor and actuator system was fabricated and characterized. After production of Carbon nanotube dispersed solution and surface modification of PVDF substrate, dip coating method was used for coating of CNTs on substrate. A coating with 75% transparency and surface resistance of 2.2 kΩ/sq was created. Then the fabricated transducer was tested in an anechoic chamber and results were compared with those of earlier researches. The fabricated transducer produced 58 dB sound under excitation with 25 V white noise. http://joasi.ir/article-1-134-en.pdf Acoustic sensor and actuator Carbon Nanotube Flexible loudspeaker. per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2019-03 6 2 46 59 article M. Rahmati Ahmadabadi rahmatimeitham@gmail.com 1 S. Esmaeelzadeh Khadem khadem@modares.ac.ir 2 M. Rasekh 3 Tarbiat Modares University In this paper, design and performance analysis of a resonance nanosensor for earthquake low frequency geoacoustic waves detection is proposed. The model comprises of a proof mass suspended to the substrate, and a nanobeam attached to the intersection of the proof mass to the substrate. The nanobeam could be cosidered as a clamped-clamped nanoresonator actuated electrostartically. The induced accelaration to the proof mass could lead to an axial tensile or compression force in the nanoresonator. The axial induced force could change the system stored potential energy and result in the shift of the resonator natural frequncy. Measuring the frequncy shift of the resonator, could lead to the estimation of the applied accelaration to the proof mass. Furthermore, the nanobeam is laminated between two piezoelectric layers wich applying voltage to them could improve the perfomance of the nanosensor. Governing equations are obtained using Hamilonian’s principle that considers the main sources of nonlinearity including electrostatic fringing field effect, piezoelectric and casimir force, and stretching effect. The equations are solved using numerical and analytical methods. The simulation results are being used to investigate the nanosensor performance charactersitics including the device dynamic response, resolution, sensitivity, bandwidth, dynamic range and the structural resitance. The results show that the proposed nano accelerometer could have a better performance compared the existing micro and macro earthquake detection devices measuring geoacoustic infrasonic and low frequency waves.   http://joasi.ir/article-1-136-en.pdf Nanosensor Earthquake detection Nonliear dynamics Resonator Multiple time scales method Infrasonic Geoacoustic.