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Ultrasonic Attenuation in Calcium Oxide  [PDF]
Jitendra Kumar, Kailash R., Sanjeev Kumar Shrivastava, Devraj Singh, Virendra Kumar
Advances in Materials Physics and Chemistry (AMPC) , 2011, DOI: 10.4236/ampc.2011.12008
Abstract: Ultrasonic attenuation studies can be used to characterize material not only after production but during processing as well. The most important causes of ultrasonic attenuation in solids are electron-phonon, phonon-phonon interaction and that due to thermo elastic relaxation. The two dominant processes that will give rise to appreciable ultrasonic attenuation at higher temperature are the phonon-phonon interaction also known as Akhiezer loss and that due to thermo elastic relaxation are observed in calcium oxide crystal. At frequencies of ultrasonic range and at higher temperatures in solids, phonon-phonon interaction mechanism is dominating cause for attenuation. Ultrasonic attenuation due to phonon-phonon interaction (α/f2)p-p and thermo elastic relaxation (α/f2)th are evaluated in Calcium Oxide crystal up to an elevated temperature from 100 K - 1500 K along <100>, <110> and <111> crystallographic directions. Temperature dependence of ultrasonic attenuation along different crystallographic direction reveals some typical characteristic features.
Ultrasonic Attenuation and Speed of Sound of Cornstarch Suspensions  [PDF]
Benjamin L. Johnson,Mark R. Holland,James G. Miller,Jonathan I. Katz
Physics , 2013, DOI: 10.1121/1.4789926
Abstract: The goal of this study is to contribute to the physics underlying the material properties of suspensions that exhibit shear thickening through the ultrasonic characterization of suspensions of cornstarch in a density-matched solution. Ultrasonic measurements at frequencies in the range of 4 to 8 MHz of the speed of sound and the frequency-dependent attenuation properties are reported for concentrations of cornstarch in a density-matched aqueous (cesium chloride brine) suspension, ranging up to 40% cornstarch. The speed of sound is found to range from 1483 +/- 10 m/s in pure brine to 1765 +/- 9 m/s in the 40% cornstarch suspension. The bulk modulus of a granule of cornstarch is inferred to be (1.2 +/- 0.1) X 10^{10} Pa. The attenuation coefficient at 5 MHz increases from essentially zero in brine to 12.0 +/- 1.2 dB/cm at 40% cornstarch.
Behavior of Ultrasonic Attenuation in MnO  [PDF]
Krishna Murti Raju
Open Journal of Acoustics (OJA) , 2013, DOI: 10.4236/oja.2013.33A009
Abstract: Temperature dependence of ultrasonic attenuation and allied parameters are investigated for manganese oxide in the temperature range 300-500 K. These calculations are made for longitudinal and shear waves along the <100>, <110> and <111> crystallographic directions of propagation. If the values of second order elastic constants and density at a particular temperature are known for any substance, one may obtain ultrasonic velocities for longitudinal and shear waves which give an important information about its internal structure, inherent and anharmonic properties. The non-linearity coupling parameters and thermal relaxation time have also obtained for this crystal. In the present investigation, it has been found that phonon-phonon interaction is the dominant cause for ultrasonic attenuation. This study will be useful in characterisation of the material and it will give a clear picture of the behaviour of ultrasonic attenuation in MnO.
Ultrasonic velocity and attenuation in carbon steel specimens
Brenda Buitrago,Ignacio Irausquín,Johnny Mendoza
Revista Técnica de la Facultad de Ingeniería Universidad del Zulia , 2004,
Abstract: La inspección y evaluación de materiales mediante el método no destructivo ultrasónico se ha convertido en una herramienta muy útil y sensible para determinar las propiedades acústicas de los mismos. En virtud de ello, este estudio ha tenido por objeto la medición de la velocidad ultrasónica longitudinal y la estimación de atenuación ultrasónica para tres muestras de acero al carbono. Esta caracterización ultrasónica se hizo mediante la técnica pulso-eco de contacto directo utilizando transductores de 0,375” (9,525 mm) de diámetro con frecuencias centrales de 1,5; 2,25; 5; 7,5 y 10 MHz, además de glicerina como medio acoplante. Los resultados mostraron una variación insignificante de la velocidad ultrasónica en el espectro de frecuencia de cada muestra y variaciones significativas de su atenuación. Así mismo se encontraron diferencias de velocidad y atenuación entre las muestras, proporcionales a su concentración de carbono. Materials testing and inspection by means of the ultrasonic nondestructive method, has become an useful and sensitive tool to determine its acoustic properties. By virtue of this, the purpose of the following study was to measure the longitudinal ultrasonic velocity and to estimate the ultrasonic attenuation for three carbon steel specimens. This ultrasonic characterization was done by means of the pulse-echo technique using transducers with a diameter of 0.375” (9.525 mm) and center frequencies of 1.5, 2.25, 5, 7.5 and 10 MHz, besides glycerin as coupling. Results showed an insignificant change in the frequency spectrum of each specimen and significant changes of its attenuation. Likewise differences in velocity and attenuation were found between the specimens, proportionally to its carbon concentration.
Ultrasonic velocity and attenuation in carbon steel specimens
Buitrago,Brenda; Irausquín,Ignacio; Mendoza,Johnny;
Revista Técnica de la Facultad de Ingeniería Universidad del Zulia , 2004,
Abstract: materials testing and inspection by means of the ultrasonic nondestructive method, has become an useful and sensitive tool to determine its acoustic properties. by virtue of this, the purpose of the following study was to measure the longitudinal ultrasonic velocity and to estimate the ultrasonic attenuation for three carbon steel specimens. this ultrasonic characterization was done by means of the pulse-echo technique using transducers with a diameter of 0.375” (9.525 mm) and center frequencies of 1.5, 2.25, 5, 7.5 and 10 mhz, besides glycerin as coupling. results showed an insignificant change in the frequency spectrum of each specimen and significant changes of its attenuation. likewise differences in velocity and attenuation were found between the specimens, proportionally to its carbon concentration.
Ultrasonic attenuation in d-wave superconductors  [PDF]
Vladimir N. Kostur,Jayanta K. Bhattacharjee,Richard A. Ferrell
Physics , 1995,
Abstract: The longitudinal ultrasonic attenuation at low temperatures for a $d$-wave superconducting order parameter is examined. The ratio of the superconducting to normal state attenuation, $\alpha_{s}/\alpha_{n}$, depends strongly on the direction of propagation of ultrasound with maxima corresponding to nodes of the order parameter on the Fermi surface. We propose that measurements of ultrasonic attenuation in a single crystal of the high-$T_{c}$ superconductors can give the information regarding the position of nodes.
Ultrasonic attenuation in clean d-wave superconductors  [PDF]
I. Vekhter,E. J. Nicol,J. P. Carbotte
Physics , 1998, DOI: 10.1103/PhysRevB.59.7123
Abstract: We consider the attenuation of longitudinal ultrasonic waves in a clean two-dimensional d-wave superconductor. We show that the attenuation coefficient is linear in temperature at low temperatures for all in-plane directions of the propagation of the ultrasound, and that the coefficient of the linear term can be used to determine the parameters crucial for the low temperature transport in these compounds.
Anomalous Ultrasonic Attenuation in Aqueous NaCl Solutions  [PDF]
Barnana Pal,Srinanda Kundu
Physics , 2012, DOI: 10.13189/ujc.2013.010304
Abstract: The velocity (v) and attenuation constant (a) for ultrasonic waves of frequencies 1MHz and 2MHz propagating through aqueous sodium chloride solution have been measured over the concentration (c) region 0-5.3 mol.L-1 at room temperature (250 C). The velocity (v) shows an overall increase with the increase of c indicating comparatively stronger bonding among the ions and water molecules prevailing in the solution. The attenuation constant, besides showing an overall increase with c, shows significantly high values at some concentrations. Attempt has been made to understand the behaviour from existing theoretical background.
ULTRASONIC ATTENUATION OF NORMAL BLOOD
血液的超声衰减研究

戴焕平,冯若
生物物理学报 , 1986,
Abstract: The ultrasonic attenuation occuring at the cell-level structure of blood due to absorption of cells, relative viscous motion of cells to the plasma and the sound scattering by cells is discussed in this paper.The theoretical prediction is well confirmed by experimental data.The analysis shows that in the contribution to the ultrasonic attenuation by the cellular structure of blood,the absorption of cells is of most importance, the part of viscous loss is below 15% and the sound scattering of cells is negligible.
Diameter Dependent Ultrasonic Characterization of InAs Semiconductor Nanowires  [PDF]
Mohit Gupta, Punit K. Dhawan, Satyendra Kumar Verma, Raja Ram Yadav
Open Journal of Acoustics (OJA) , 2015, DOI: 10.4236/oja.2015.54017
Abstract: In this paper, we report the diameter dependent ultrasonic characterization of wurtzite structured InAs semiconductor nanowires at the room temperature. In this work, we have calculated the non-linear higher order elastic constants of InAs nanowires validating the interaction potential model. The ultrasonic attenuation and velocity in the nanowires are determined using the elastic constants for different diameters of the nanowires. Where possible, the results are compared with the experiments. Finally, we have established the correlation between the size dependent thermal conductivity and the ultrasonic attenuation of the nanowires.
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