scholarly journals Determination of the parameters of cancellous bone using high frequency acoustic measurements

2007 ◽  
Vol 45 (3-4) ◽  
pp. 281-308 ◽  
Author(s):  
James L. Buchanan ◽  
Robert P. Gilbert
Keyword(s):  
Cancellous Bone ◽  
High Frequency ◽  
Acoustic Measurements

scholarly journals DETERMINATION OF THE PARAMETERS OF CANCELLOUS BONE USING HIGH FREQUENCY ACOUSTIC MEASUREMENTS II: INVERSE PROBLEMS

2007 ◽  
Vol 15 (02) ◽  
pp. 199-220 ◽  
Author(s):  
JAMES L. BUCHANAN ◽  
ROBERT P. GILBERT
Keyword(s):  
Cancellous Bone ◽  
High Frequency ◽  
Acoustic Pressure ◽  
Measured Data ◽  
Acoustic Measurements ◽  
Biot Model ◽  
Parameter Recovery ◽  
Recovery Algorithm ◽  
Poroelastic Media

In a precursor to this article the Biot model was used to model poroelastic media. The question this article addresses is whether the sort of experiments described by McKelvie and Palmer, Williams, and Hosokawa and Otani can be used to determine the parameters of the Biot model. A method of computing acoustic pressure in the low 100 kHz range was developed in Buchanan and Gilbert, "Determination of the parameters of cancellous bone using high frequency acoustic measurements," which appeared in Math. Comput. Modelling. In the present work a parameter recovery algorithm which uses parallel processing is developed and tested. It is found that when it is assumed that the agreement between calculated and measured data is about two digits, porosity can be determined to within about 1–2% and permeability, pore size and the bulk moduli to within about 40%, but in most cases less than 20%.

Determination of cancellous bone density using low frequency acoustic measurements

2008 ◽  
Vol 87 (10-11) ◽  
pp. 1213-1225 ◽  
Author(s):  
Robert P. Gilbert ◽  
Philippe Guyenne ◽  
George C. Hsiao
Keyword(s):  
Bone Density ◽  
Cancellous Bone ◽  
Low Frequency ◽  
Acoustic Measurements

DETERMINATION OF THE PARAMETERS OF CANCELLOUS BONE USING LOW FREQUENCY ACOUSTIC MEASUREMENTS

2004 ◽  
Vol 12 (02) ◽  
pp. 99-126 ◽  
Author(s):  
JAMES L. BUCHANAN ◽  
ROBERT P. GILBERT ◽  
KHALDOUN KHASHANAH
Keyword(s):  
Cancellous Bone ◽  
Low Frequency ◽  
Acoustic Measurements ◽  
Biot Model ◽  
Poroelastic Media ◽  
High Degree

The Biot model is widely used to model poroelastic media. Several authors have studied its applicability to cancellous bone. In this article the feasibility of determining the Biot parameters of cancellous bone by acoustic interrogation using frequencies in the 5–15 kHz range is studied. It is found that the porosity of the specimen can be determined with a high degree of accuracy. The degree to which other parameters can be determined accurately depends upon porosity.

Magnetic Permeability and Relaxation Frequency in High Frequency Magnetic Materials.

2001 ◽  
Vol 674 ◽  
Author(s):  
M.I. Rosales ◽  
H. Montiel ◽  
R. Valenzuela
Keyword(s):  
High Frequency ◽  
Domain Walls ◽  
Magnetocrystalline Anisotropy ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Anisotropy Constant ◽  
Relaxation Frequency ◽  
Resonance Relaxation ◽  
Frequency Behavior

ABSTRACTAn investigation of the frequency behavior of polycrystalline ferrites is presented. It is shown that the low frequency dispersion (f < 10 MHz) of permeability is associated with the bulging of pinned domain walls, and has a mixed resonance-relaxation character, closer to the latter. It is also shown that there is a linear relationship between the magnetocrystalline anisotropy constant, K1, and the relaxation frequency. The slope of this correlation depends on the grain size. Such a relationship could allow the determination of this basic parameter from polycrystalline samples.

Design and Construction of a Small Reverberation Chamber Applied to Absorption and Scattering Acoustic Measurements

2014 ◽  
Vol 1077 ◽  
pp. 197-202
Author(s):  
D. Hernandez ◽  
E.J. Liu ◽  
J.H. Huang ◽  
Y.C. Liu
Keyword(s):  
High Frequency ◽  
Integration Method ◽  
Sound Field ◽  
Acoustic Measurements ◽  
Acoustic Characteristics ◽  
Reverberation Chamber ◽  
Scattering Coefficients ◽  
Reverberation Chambers ◽  
The Cost ◽  
Design And Construction

Reverberation chambers are used to create a diffuse incidence sound field, where multiple types of acoustic measurements can be performed. The chambers tend to have a large volume in order to extent the reverberation time. However, this requirement may be conditioned by the cost and the infrastructure limitations. This paper presents the design and construction of a small-scaled reverberation chamber of 3 m3 for middle-high frequency acoustic measurements. On the design, the acoustic characteristics of chamber are confirmed via finite element computer simulation. As case studies, absorption and scattering coefficients of several materials and diffusors are measured. The reverberation times needed for the measurements were obtained by the impulse response integration method. The small reverberation chamber demonstrated to be a reliable tool for middle and high frequency acoustic measurements.

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