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Mechanical Engineering Commons

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1993

Thermodynamics

Articles 1 - 5 of 5

Full-Text Articles in Mechanical Engineering

Structure Characterization With Thermal Wave Imaging, Kurt Bryan Jan 1993

Structure Characterization With Thermal Wave Imaging, Kurt Bryan

Review of Progress in Quantitative Nondestructive Evaluation

Thermal imaging is a technique of recent interest for the nondestructive evaluation of materials. This method attempts to characterize the internal structure of a sample (perhaps to locate flaws-cracks, bubbles, corrosion, etc.) by using its surface temperature response to an external heating. Some recent work on this subject is detailed in [2], [3], [4] and [6].


Dual-Band Infrared Imaging Applications: Locating Buried Minefields, Mapping Sea Ice And Inspecting Aging Aircraft, Nancy Del Grande, Philip F. Durbin, Dwight E. Perkins Jan 1993

Dual-Band Infrared Imaging Applications: Locating Buried Minefields, Mapping Sea Ice And Inspecting Aging Aircraft, Nancy Del Grande, Philip F. Durbin, Dwight E. Perkins

Review of Progress in Quantitative Nondestructive Evaluation

We discuss the use of dual-band infrared (DBIR) imaging for three quantitative NDE applications: locating buried surrogate mines, mapping sea ice thicknesses and inspecting subsurface flaws in aging aircraft parts. Our system of DBIR imaging offers a unique combination of thermal resolution, detectability, and interpretability. Pioneered at Lawrence Livermore Laboratory, it resolves 0.2 °C differences in surface temperatures needed to identify buried mine sites and distinguish them from surface features. It produces both surface temperature and emissivity-ratio images of sea ice, needed to accurately map ice thicknesses (e.g., by first removing clutter due to snow and surface roughness ...


Photothermal Measurement Of Metal Film Thickness In Integrated Circuit Devices, Xioa-Dung Wu, Gordon S. Kino Jan 1993

Photothermal Measurement Of Metal Film Thickness In Integrated Circuit Devices, Xioa-Dung Wu, Gordon S. Kino

Review of Progress in Quantitative Nondestructive Evaluation

Metal films have been used extensively in very-large-scale integration (VLSI) devices. They are used to build interconnects, field-effect transistor gates, diffusion barriers, and conduction pads for input or output leads. Metals such as aluminum, tungsten, titanium and platinum are deposited on an insulating layer [1,2]. The metal film thicknesses range from 100 Å to 1 µm. Due to the ever-growing need for high speed, high density, and low power dissipation in integrated circuit (IC) technology, accurate control of the metallization process becomes essential to ensure the quality and yield of the final product. One of the important parameters in ...


Thermal Wave Detection And Analysis Of Defects In Structural Composite Materials, D. Crowther, L. D. Favro, P.-K. Kuo, R. L. Thomas Jan 1993

Thermal Wave Detection And Analysis Of Defects In Structural Composite Materials, D. Crowther, L. D. Favro, P.-K. Kuo, R. L. Thomas

Review of Progress in Quantitative Nondestructive Evaluation

One criticism which can be leveled at thermal wave images is that their resolution is often less than that of the very best ultrasonic images of similar targets. This reduction of the resolution arises from the transverse diffusion of heat in the thermal waves reflected from the subsurface defects in the sample. In this paper we describe a technique for removing the blurring of pulsed thermal wave images of planar defects through the reconstruction of the shape of the scatterer by use of inverse scattering techniques. Although the method at present is restricted to planar defects, this special class of ...


Thermal Method For Depth Of Damage Determination In Insulating Materials, P. Howell, K. Elliott Cramer, William P. Winfree Jan 1993

Thermal Method For Depth Of Damage Determination In Insulating Materials, P. Howell, K. Elliott Cramer, William P. Winfree

Review of Progress in Quantitative Nondestructive Evaluation

Impact damage often may produce little visible surface damage, yet extensive subsurface delaminations, greatly reducing the load carrying capacity of the composite part [1]. For large composite structures typical of aerospace applications, thermal NDE techniques have been shown to provide quantitative information regarding the area and depth of hidden damage in composite samples [2] [3]. For a quantitative assessment of damage, where a noncontacting method capable of imaging large areas at a time is required, thermal techniques have some advantages.