In Situ Monitoring of the Synthesis of a Pyranine-Substituted Phthalonitrile Derivative via the Steady-State Fluorescence Technique

2007 ◽  
Vol 111 (2) ◽  
pp. 478-484 ◽  
Author(s):  
Ali Gelir ◽  
İsmail Yılmaz ◽  
Yaşar Yılmaz
Keyword(s):  
Steady State ◽  
In Situ Monitoring ◽  
Fluorescence Technique ◽  
Steady State Fluorescence

Prolonged Steady-State Exposure of Printed Wiring Boards Under Conditions of Temperature Humidity and Bias

2005 ◽  
Author(s):  
M. Reid ◽  
J. Punch ◽  
B. Rodgers ◽  
T. Galkin ◽  
T. Stenberg ◽  
...  
Keyword(s):  
Steady State ◽  
In Situ Monitoring ◽  
Printed Wiring Boards ◽  
Ambient Conditions ◽  
Moisture Condensation ◽  
Current Densities ◽  
The Subject ◽  
Investigative Techniques ◽  
Electrochemical Phenomena

Ionic migration has been the subject of intensive study, both theoretical and experimental, over the past 40 years. It is known as a reliability concern for printed wiring boards (PWBs) in high density microelectronic packaging and power electronic packaging. Ionic migration is an electrochemical phenomena that occurs primarily under normal ambient conditions: i.e. when the local temperatures and current densities are low enough to allow moisture on the surface. Standardised test 85°C/85%RH is typically used for accelerating and predicting ionic migration failure, however, the possibility of moisture condensation — a prerequisite for ionic migration — at a relatively high temperature and low relative humidity is unlikely. In order to assess more realistic and less thermally severe environments, this work examines prolonged steady state exposure of PWBs. Steady-state conditions of 90%RH at 30°C under a bias of 5V DC were tested over a 210 day period with continuous in-situ monitoring of dendritic growth. Investigative techniques were conducted to evaluate the migration development on the PWBs after testing using optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS). This paper will demonstrate that steady-state thermal humidity bias (THB) tests appear to provide ionic migration behaviour similar in service conditions, however, do not demonstrate the dramatic failure associated with ionic migration.

Defect Detection in Additively Manufactured Metal Parts Using In-Situ Steady-State Ultrasonic Response Data

2020 ◽  
Author(s):  
Erica M. Jacobson ◽  
Ian T. Cummings ◽  
Peter H. Fickenwirth ◽  
Eric B. Flynn ◽  
Adam J. Wachtor
Keyword(s):  
Quality Control ◽  
Steady State ◽  
Defect Detection ◽  
Three Dimensional ◽  
Early Termination ◽  
In Situ Monitoring ◽  
Safety Critical ◽  
Response Data ◽  
Processing Techniques

Abstract The increasing implementation of additively manufactured parts into safety-critical applications is accelerating the demand for non-destructive evaluation as a means of quality control for defect detection during the build process. Identification of a critical defect in the part before its completion can enable early termination of the build, resulting in both reduced material costs and machine time. Additionally, current post-build inspection techniques have limited resolution capability as the size of the manufactured part increases. An adaptation of Acoustic Wavenumber Spectroscopy technology was implemented into a laser powder bed fusion machine to perform in-situ direct-part measurements and provide a three-dimensional inspection volume of the entire build. The processing of data for each layer is quick enough to be performed during the lasing of the subsequent layer, enabling the potential for early termination of the build when critical defects are identified. Various processing techniques were used to detect changes in the steady-state ultrasonic response that indicate different defect types. The data analyses used to identify regions of defects based on the response data are presented. This work ultimately demonstrates a practical means for in-situ monitoring of additive manufacturing parts to ensure quality control for safety-critical applications.

Development and Testing of a Multitransducer System for Measuring Height of Condensed Water in Steam Pipes With Steady-State and Turbulent Flow Conditions

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Shyh-Shiuh Lih ◽  
Hyeong Jae Lee ◽  
Yoseph Bar-Cohen ◽  
Mircea Badescu
Keyword(s):  
Signal Processing ◽  
Steady State ◽  
Turbulent Flow ◽  
In Situ Monitoring ◽  
Flow Conditions ◽  
Dynamic Surface ◽  
Steam Pipes ◽  
Turbulent Flow Conditions ◽  
Water Height

A system consisting of a multiplexer and multiple ultrasonic probes was developed for in situ monitoring of the water condensation height in steam pipes under steady-state and turbulent flow conditions. The measurement method, the signal processing techniques, the experimental setup, and the test results are presented in this paper. The feasibility and efficiency of the developed multitransducers and signal processing algorithms were demonstrated. The measured water height and wave pattern in dynamic surface conditions inside the pipe were verified through the snapshot of the recorded video images. The developed methodology built the framework for the use of multiple transducers array ultrasonic system for practical application to in situ monitor the water height in steam pipes.

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