A room acoustics measurement system round robin

1995 ◽  
Vol 97 (5) ◽  
pp. 3318-3318
Author(s):  
J. S. Bradley
1997 ◽  
Vol 4 (4) ◽  
pp. 229-246 ◽  
Author(s):  
Michael Vorländer

In the last decade computer simulations of sound fields in rooms have been developed for application in research and consulting. Some programs are commercially available. Most computer models are based on geometrical room acoustics and/or on statistical (radiosity) methods, thus not including wave phenomena such as diffraction. The uncertainty of typical simulation software was investigated in an international verification test in 1994 and 1995. The results were partly promising although some programs were not as reliable as the operators expected. These round robin tests have been continued until today with simulations and measurements in a concert hall in Jönköping in Sweden. In this paper the basic algorithms of room acoustical computer simulations, the verification in round robin tests and the observed accuracy and limitations are summarised. Finally, possible improvements are discussed.


Author(s):  
Takayasu Tahara ◽  
Takuyo Kaida ◽  
Minoru Niimura ◽  
Shinsuke Sakai

FFS assessment technologies for pressure equipment have been studied and standardized in recent 15 years in Japan. FFS assessment of local thin area, LTA, is the most frequently used in process industries. However reliability of thickness measurement of LTA and influence to FFS assessment has not been studied much in the past. Uncertainty of thickness measurements and Remaining Strength Factor, RSF, were investigated on Round Robin Testing using manual UT and additional new technology such as flexi-alley UT and 3D LED system for LTA in pipes, It is recommended to use suitable combination of Manual or mechanized UT and 3D LTA measurement system in case of assessment of critical flaws and decision making for repair and replacement of pressure equipment.


1996 ◽  
Vol 100 (4) ◽  
pp. 2837-2838
Author(s):  
Edward Kahle ◽  
Robert Essert

1989 ◽  
Vol 146 ◽  
Author(s):  
C. B. Yarling ◽  
W.A. Keenan

ABSTRACTThe Greater Silicon Valley Implant Users' Group (GSVIUG) has conducted a round robin to determine the uniformity and repeatability available in wafers processed with modern RTP equipment. High-dose ion implantation (As, 5E15, 80keV) of 150mm wafers was used to monitor temperature distribution through sheet resistance. Sheet resistance maps were then used to compare the uniformity and repeatability of each vendor. As previously reported, the actual uniformity results varied significantly with RTP vendor and implant conditions, ranging from 0.77% (one sigma/mean) to 3.55%. In addition, some contour patterns were quite representative of specific vendors.Subsequently, wafers from each participating vendor were evaluated by three techniques in order to determine what damage or defects might have resulted from the RTP process: laser flatness measurement, optical-imaging inspection, and thermal wave measurement. The flatness measurement system was used to measure the warpage of each sample. The reflective-optical inspection technique is a full-field, non-destructive technique that provides a real-time visual display, evidenced by light and dark field contrast over the entire wafer. The thermal wave measurement system uses two laser probes to measure a difference in modulated reflectance which results from damage or defects within the wafer.This paper describes each of the three techniques and summarizes the measured results of wafer defects and damage due to the processing by various RTP vendors. Comparisons between the three measurement techniques are made.


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