Results 221 to 230 of about 15,049 (256)

Determining Subsurface Defects’ Depth in CFRP Composites Using Lock-In Thermography

2021
The lock-in infrared thermography technique was used for inspecting a carbon fiber reinforced polymer (CFRP) sample to detect and to determine the depth of internal defects located underneath its top surface. The frequency dependency of incident modulated light on heat transport through the sample is explored to investigate its effect on the emitted ...
Carlos Manzano, Jonathan Zheng, Vinod Kumar, Andrew Ngo   +3 more
openaire   +1 more source

A sensor to monitor limb depth in transtibial sockets with locking pin suspension: a technical note

Prosthetics & Orthotics International, 2021
Background: Monitoring of limb depth in transtibial sockets may provide useful information toward patient education and care. Objective: The objective was to develop a sensor to detect the depth of a locking pin in the shuttle lock of a transtibial socket and to monitor the small ...
Sam Bennett, Clement Gurrey, Horace Wang, Mathew Weissinger, Brian Larsen, Joan E. Sanders   +5 more
openaire   +2 more sources

Modulation method for minimizing the depth distortion offset of lock-in TOF cameras

2013 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2013
Registered depth and intensity data at a high frame rate, a compact design, low weight and a reduced power consumption have motivated the increasing usage of lock-in time-of-flight cameras in research areas such as computer graphics, machine vision and robotics.
Stephan Hussmann, Florian Johannes Knoll
openaire   +1 more source

Depth estimation of surface cracks on metallic components by means of lock-in thermography

Review of Scientific Instruments, 2013
In this work, a new method to characterize vertical cracks by lock-in thermography is presented. The heat transfer process induced by a modulated thermal excitation located in the vicinity of the crack is simulated using a finite element method computer package.
M, Streza, D, Dadarlat, Y, Fedala, S, Longuemart   +3 more
openaire   +2 more sources

Ultrasound lock-in thermography for advanced depth resolved defect selective imaging

Insight - Non-Destructive Testing and Condition Monitoring, 2007
Ultrasound lock-in thermography ('attenuation mapping') is a defect selective 'dark field' NDT technique with a high probability of defect detection (PoD), since only defects produce a signal while other features are suppressed. The basic contrast mechanism is the enhanced local mechanical loss turning a variably loaded defect into a heat source.
A Gleiter, G Riegert, Th Zweschper, G Busse   +3 more
openaire   +1 more source

Performance analysis of locking policies with limited wait depth

Proceedings of the 1992 ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems, 1992
The performance of a transaction processing system with the standard two-phase locking (2PL) concurrency control (CC) method (with the general waiting policy upon a lock conflict) may be degraded significantly due to transaction blocking in a high lock contention environment. In the limit this effect leads to the thrashing
openaire   +1 more source

Defect Z-depth Determination in Flip-chip using lock-in thermography

2017 IEEE 24th International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA), 2017
This paper describes the use of Lock-In Thermography (LIT) technique to determine the defect Z-depth in flip chip. An empirical phase shift versus applied lock-in frequency plot for Flip-chip is first created by using samples with known defect Z-depth.
Wen Qiu, Bemice Zee, Herve Deslandes, Brian Lai, David Tien   +4 more
openaire   +1 more source

Investigation of lock-in infrared thermography for evaluation of subsurface defects size and depth

International Journal of Precision Engineering and Manufacturing, 2015
In this study, the investigation on lock-in infrared thermography was done for the detection and estimation of artificial subsurface defects size and depth in stainless steel sample. The experimental and the finite element analysis were performed at several excitation frequencies to interrogate the sample ranging from 0.182 down to 0.021 Hz.
Shrestha Ranjit, Kisoo Kang, Wontae Kim
openaire   +1 more source

Video Detection System Design of Meshing Depth of Elevator’s Door Lock

Advanced Materials Research, 2012
The detection of meshing depth of elevator’s door lock is an important content in the detections of elevator safety performance. Based on machine vision and the principle of image processing, this paper established a detection system of meshing depth of elevator’s door lock, and designed a handheld instrument.
Zhi Yuan LU, Bo Zhao, Tie Liu, Yun Peng Song, You Meng Zhang   +4 more
openaire   +1 more source

Open crack depth sizing by laser stimulated infrared lock-in thermography

Journal of Physics D: Applied Physics, 2014
Recent advances in infrared imaging have made active thermography an interesting non destructive technique for sub-surface defect detection. Here, we present a method for the estimation of the depth of open surface defects by infrared lock-in thermography, based on the relation between the crack depth and the Laplacian of the surface temperature ...
Y Fedala, M Streza, J-P Roger, G Tessier, C Boué   +4 more
openaire   +1 more source