Scanning acoustic microscopy of biological cryosections: the effect of local thickness on apparent acoustic wave speed

2014 ◽  
Vol 1621 ◽  
pp. 143-148
Author(s):  
Craig J. Williams ◽  
Helen. K. Graham ◽  
Xuegen Zhao ◽  
Riaz Akhtar ◽  
Christopher E.M. Griffiths ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Wave Speed ◽  
Acoustic Microscopy ◽  
Specimen Thickness ◽  
Sampling Point ◽  
Scanning Acoustic Microscopy ◽  
Glass Slides ◽  
Nominal Thickness ◽  
Longitudinal Acoustic Wave ◽  
Multiple Regions

ABSTRACTScanning acoustic microscopy (SAM), when applied to biological samples has the potential to resolve the longitudinal acoustic wave speed and hence stiffness of discrete tissue components. The heterogeneity of biological materials combined with the action of cryosectioning and rehydrating can, however, create variations in section topography. Here, we set out to determine how variations in specimen thickness influence apparent acoustic wave speed measurementsCryosections (5μm nominal thickness) of human skin biopsies were adhered to glass slides before washing and rehydrating in water. Multiple regions (200x200 μm; n = 3) were imaged by SAM to generate acoustic wave speed maps. Subsequently co-localised 30x30 μm sub-regions were imaged by atomic force microscopy (AFM) in fluid. The images were then registered using Image J. Each pixel was allocated both a height and wave speed value before their relationship was then plotted on a scattergram. The mean section thickness measured by AFM was 3.48 ± 1.12 (SD) μm. Regional height variations influenced apparent wave speed measurements. A 3.5 μm height difference was associated with a 400 ms-1 increase in wave speed. In the present study we show that local variations in specimen thickness influence apparent wave speed. We also show that a true measure of wave speed can be calculated if the thickness of the specimen is known at each sampling point.

scholarly journals Mapping the Micromechanical Properties of Cryo-sectioned Aortic Tissue with Scanning Acoustic Microscopy

2008 ◽  
Vol 1132 ◽  
Author(s):  
Riaz Akhtar ◽  
Michael J. Sherratt ◽  
Rachel E.B. Watson ◽  
Tribikram Kundu ◽  
Brian Derby
Keyword(s):  
Mechanical Properties ◽  
Acoustic Wave ◽  
Wave Speed ◽  
Biological Tissues ◽  
Elastic Fibre ◽  
Acoustic Microscopy ◽  
Aortic Tissue ◽  
Scanning Acoustic Microscopy ◽  
Frequency Scanning ◽  
Adventitial Layer

ABSTRACTAlthough the gross mechanical properties of ageing tissues have been extensively documented, biological tissues are highly heterogeneous and little is known concerning the variation of micro-mechanical properties within tissues. Here, we use Scanning Acoustic Microscopy (SAM) to map the acoustic wave speed (a measure of stiffness) as a function of distance from the outer adventitial layer of cryo-sectioned ferret aorta. With a 400 MHz lens, the images of the aorta samples matched those obtained following chemical fixation and staining of sections which were viewed with fluorescence microscopy. Quantitative analysis was conducted with a frequency scanning or V(f) technique by imaging the tissue from 960 MHz to 1.1 GHz. Undulating acoustic wave speed (stiffness) distributions corresponded with elastic fibre locations in the tissue; there was a decrease in wave speed of around 40 ms-1 from the adventitia (outer layer) to the intima (innermost).

Characterization of Stress at a Ceramic/Metal Joined Interface by the Vz Technique of Scanning Acoustic Microscopy

2002 ◽  
Vol 124 (3) ◽  
pp. 336-342 ◽  
Author(s):  
Chiaki Miyasaka ◽  
Bernard R. Tittmann ◽  
Shun-Ichiro Tanaka
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Wave Velocity ◽  
Dissimilar Materials ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wave Velocities

It is well known that the process of heating and then cooling dissimilar materials introduces considerable stress at and near the interface. In this article, first, the surface wave velocity distributions obtained with the Vz curve technique were found to compare well with residual stress distribution measured by the finely collimated X-ray diffraction technique. Second, a delamination was introduced at the interface. The Vz curve technique was then used again to measure the surface acoustic wave velocity along the interface. The defective specimens showed significantly different patterns of surface acoustic wave velocities. Thus, this study presents useful guidelines in discriminating between sound and defective ceramic/metal joints by scanning acoustic microscopy.

scholarly journals Quantifying Micro-mechanical Properties of Soft Biological Tissues with Scanning Acoustic Microscopy

2011 ◽  
Vol 1301 ◽  
Author(s):  
Xuegen Zhao ◽  
Steven Wilkinson ◽  
Riaz Akhtar ◽  
Michael J Sherratt ◽  
Rachel E B Watson ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Wave Attenuation ◽  
Substrate Surface ◽  
Biological Tissues ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Phase Information ◽  
Soft Biological Tissues ◽  
Acoustic Lens

ABSTRACTIn this study we have established a new approach to more accurately map acoustic wave speed (which is a measure of stiffness) within soft biological tissues at micrometer length scales using scanning acoustic microscopy. By using thin (5 μm thick) histological sections of human skin and porcine cartilage, this method exploits the phase information preserved in the interference between acoustic waves reflected from the substrate surface as well as internal reflections from the acoustic lens. A stack of images were taken with the focus point of acoustic lens positioned at or above the substrate surface, and processed pixel by pixel using custom software developed with LABVIEW and IMAQ (National Instruments) to extract phase information. Scanning parameters, such as acoustic wave frequency and gate position were optimized to get reasonable phase and lateral resolution. The contribution from substrate inclination or uneven scanning surface was removed prior to further processing. The wave attenuation was also obtained from these images.

Characterization of Material Degradation in Epoxy Film Based on Scanning Acoustic Microscopy (SAM)

2006 ◽  
Vol 321-323 ◽  
pp. 578-581 ◽  
Author(s):  
Noh Yu Kim ◽  
Hwan Seon Nah ◽  
Sang Soon Lee
Keyword(s):  
Acoustic Wave ◽  
Nuclear Power ◽  
Power Plants ◽  
Accelerated Aging ◽  
Epoxy Coating ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Aging Conditions

In order to evaluate the degradation of the epoxy coating in nuclear power plants, acoustic wave velocities of epoxy films are measured using defocused scanning acoustic microscopy system(SAM). Unlike metals, the surface of the epoxy coating on the concrete liner is so thin and wavy that the conventional ultrasonic techniques for acoustic velocity of epoxy coating are hard to apply. Acoustic velocities of bulk waves are determined from V(z,t) curves of mode-converted waves generated in the film by SAM. Epoxy films are fabricated and degraded under various accelerated aging conditions, and both of longitudinal and shear wave velocities of the epoxy film are measured. Approximately 10% of reduction in acoustic wave velocity is observed from experimental results when the aging is developed fully in epoxy films. It is also found that longitudinal wave is more sensitive to deterioration of epoxy coating than transverse wave.

Counterfeit Parts Recognition and Detection for Failure Analysts

2010 ◽  
Author(s):  
Katherine V. Whittington
Keyword(s):  
Thermal Cycle ◽  
Visual Inspection ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
3D Measurement ◽  
X Ray ◽  
Wide Range ◽  
Electronic Parts ◽  
Testing Awareness

Abstract The electronics supply chain is being increasingly infiltrated by non-authentic, counterfeit electronic parts, whose use poses a great risk to the integrity and quality of critical hardware. There is a wide range of counterfeit parts such as leads and body molds. The failure analyst has many tools that can be used to investigate counterfeit parts. The key is to follow an investigative path that makes sense for each scenario. External visual inspection is called for whenever the source of supply is questionable. Other methods include use of solvents, 3D measurement, X-ray fluorescence, C-mode scanning acoustic microscopy, thermal cycle testing, burn-in technique, and electrical testing. Awareness, vigilance, and effective investigations are the best defense against the threat of counterfeit parts.

Failure Analysis of Broken Stitch Bonds in TSSOP Packages Using Scanning Acoustic Microscopy (SAM) and Time Domain Reflectometry (TDR)

2004 ◽  
Author(s):  
Bilal Abd-AlRahman ◽  
Corey Lewis ◽  
Todd Simons
Keyword(s):  
Failure Analysis ◽  
Mechanical Stress ◽  
Time Domain ◽  
Open Circuit ◽  
Time Domain Reflectometry ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Root Cause ◽  
Analysis Application

Abstract A failure analysis application utilizing scanning acoustic microscopy (SAM) and time domain reflectometry (TDR) for failure analysis has been developed to isolate broken stitch bonds in thin shrink small outline package (TSSOP) devices. Open circuit failures have occurred in this package due to excessive bending of the leads during assembly. The tools and their specific application to this technique as well as the limitations of C-SAM, TDR and radiographic analyses are discussed. By coupling C-SAM and TDR, a failure analyst can confidently determine whether the cause of an open circuit in a TSSOP package is located at the stitch bond. The root cause of the failure was determined to be abnormal mechanical stress placed on the pins during the lead forming operation. While C-SAM and TDR had proven useful in the analysis of TSSOP packages, it can potentially be expanded to other wire-bonded packages.

Stacked Die Analysis Using C-mode Scanning Acoustic Microscope

2005 ◽  
Author(s):  
Li Na ◽  
Jawed Khan ◽  
Lonnie Adams
Keyword(s):  
Data Acquisition ◽  
Image Interpretation ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Acoustic Microscope ◽  
Analysis Mode ◽  
Scanning Acoustic Microscope

Abstract For stacked die package delamination inspection using C-mode acoustic microscope, traditional interface and thorough scan techniques cannot give enough of information when the delamination occurs in multi-interfaces, and echoes from adjacent interfaces are not sufficiently separated from each other. A thinner thickness in the stacked-die package could complicate C-mode scanning acoustic microscopy (CSAM) analysis and sometimes may lead to false interpretations. The first objective of this paper is to briefly explain the CSAM mechanism. Based on that, some of the drawbacks of current settings in detecting the delamination for stacked-die packages are presented. The last objective is to introduce quantitative B-scan analysis mode (Q-BAM) and Zip-Slice technologies in order to better understand and improve the reliability of detecting the delamination in stacked-die packages. Therefore, a large portion of this paper focuses on the Q-BAM and Zip-Slice data acquisition and image interpretation.

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