Accuracy of Elastic Property Measurement in Mandibular Cortical Bone is Improved by Using Cylindrical Specimens

2002 ◽  
Vol 124 (6) ◽  
pp. 714-723 ◽  
Author(s):  
C. L. Schwartz-Dabney ◽  
P. C. Dechow
Keyword(s):  
Cortical Bone ◽  
Elastic Properties ◽  
Specimen Thickness ◽  
Velocity Measurements ◽  
Ultrasonic Velocities ◽  
Lack Of Information ◽  
Ultrasonic Determination ◽  
Property Measurement ◽  
Cylindrical Samples

Ultrasonic determination of elastic properties in human craniofacial cortical bone is problematic because of a lack of information about the principal material axes, and because the cortex is often thinner than in long bones. This study investigated solutions that permit reasonable determination of elastic properties in the human mandible. We tested whether ultrasonic velocities could be reliably measured in cylindrical samples of aluminum and mandibular bone, and the effects of reduced specimen thickness. Results indicted that (1) varying shape had minimal effects on ultrasonic velocities or derived elastic properties, and (2) ultrasonic velocities have relatively increased measurement error as propagation distances decreased. The increased error in velocity measurements of mandibular cortical specimens of less than 1.2 mm in thickness should be considered when assessing the reliability of single measurements.

Ultrasonic determination of the elastic modulus of human cortical bone

1998 ◽  
Vol 36 (1) ◽  
pp. 51-56 ◽  
Author(s):  
K. D. Hunt ◽  
V. Dean O'Loughlin ◽  
D. W. Fitting ◽  
L. Adler
Keyword(s):  
Elastic Modulus ◽  
Cortical Bone ◽  
Human Cortical Bone ◽  
Ultrasonic Determination

Ultrasonic determination of the elastic properties and their pressure and temperature dependences in very denseYBa2Cu3O7−x

1992 ◽  
Vol 46 (2) ◽  
pp. 1157-1165 ◽  
Author(s):  
M. Cankurtaran ◽  
G. A. Saunders ◽  
K. C. Goretta ◽  
R. B. Poeppel
Keyword(s):  
Elastic Properties ◽  
Temperature Dependences ◽  
Ultrasonic Determination

Determination of the Elastic Properties at Aging of Medical Ti-6Al-4V ELI Alloy by Ultrasonic Velocity Measurements

2020 ◽  
Vol 23 (1) ◽  
pp. 32-38
Author(s):  
H. Carreon ◽  
M. Carreon-Garcidueñas ◽  
M. L. Carreon ◽  
V. Almanza
Keyword(s):  
Elastic Properties ◽  
Ultrasonic Velocity ◽  
Velocity Measurements

Experimental Determination of the Effective Resolution Limit in Thick Specimens at High Voltages

1975 ◽  
Vol 33 ◽  
pp. 664-665
Author(s):  
Mircea Fotino
Keyword(s):  
Experimental Approach ◽  
Chromatic Aberration ◽  
Resolving Power ◽  
Biological Research ◽  
Specimen Thickness ◽  
Resolution Limit ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Resolution Level

The use of thick specimens (0.5 μm to 5.0 μm or more) is one of the most resourceful applications of high-voltage electron microscopy in biological research. However, the energy loss experienced by the electron beam in the specimen results in chromatic aberration and thus in a deterioration of the effective resolving power. This sets a limit to the maximum usable specimen thickness when investigating structures requiring a certain resolution level.An experimental approach is here described in which the deterioration of the resolving power as a function of specimen thickness is determined. In a manner similar to the Rayleigh criterion in which two image points are considered resolved at the resolution limit when their profiles overlap such that the minimum of one coincides with the maximum of the other, the resolution attainable in thick sections can be measured by the distance from minimum to maximum (or, equivalently, from 10% to 90% maximum) of the broadened profile of a well-defined step-like object placed on the specimen.

Problems in Thin-Film X-ray Quantification

1990 ◽  
Vol 48 (2) ◽  
pp. 458-459
Author(s):  
J N Chapman ◽  
W A P Nicholson
Keyword(s):  
Thin Film ◽  
Specimen Thickness ◽  
X Rays ◽  
Characteristic Peak ◽  
Local Composition ◽  
X Ray ◽  
Measured Ratio ◽  
Path Lengths ◽  
Composition Changes

Energy dispersive x-ray microanalysis (EDX) is widely used for the quantitative determination of local composition in thin film specimens. Extraction of quantitative data is usually accomplished by relating the ratio of the number of atoms of two species A and B in the volume excited by the electron beam (nA/nB) to the corresponding ratio of detected characteristic photons (NA/NB) through the use of a k-factor. This leads to an expression of the form nA/nB = kAB NA/NB where kAB is a measure of the relative efficiency with which x-rays are generated and detected from the two species.Errors in thin film x-ray quantification can arise from uncertainties in both NA/NB and kAB. In addition to the inevitable statistical errors, particularly severe problems arise in accurately determining the former if (i) mass loss occurs during spectrum acquisition so that the composition changes as irradiation proceeds, (ii) the characteristic peak from one of the minority components of interest is overlapped by the much larger peak from a majority component, (iii) the measured ratio varies significantly with specimen thickness as a result of electron channeling, or (iv) varying absorption corrections are required due to photons generated at different points having to traverse different path lengths through specimens of irregular and unknown topography on their way to the detector.

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