Life and reliability of rotating disks

In aerospace applications, an engineer must be especially cognizant of size and weight constraints which affect design decisions. Although designing at or below the material fatigue limit may be desirable in most industrial applications, in aerospace application it is almost mandatory to design certain components for a finite life at an acceptable probability of survival. Zaretsky outlined such a methodology based in part on the work of W. Weibull (1939, 1951) and G. Lundberg and A. Palmgren (1947a, 1947b, 1952). It is the objective of this work to apply the method of Zaretsky (1987) to statistically predict the life of a generic solid disk with and without bolt holes; determine the effect of disk design variables, thermal loads, and speed on relative life; and develop a generalized equation for determining disk life by incorporating only these variables

Probabilistic Analysis of Aircraft Gas Turbine Disk Life and Reliability

Two series of low cycle fatigue (LCF) test data for two groups of different aircraft gas turbine engine compressor disk geometries were reanalyzed and compared using Weibull statistics. Both groups of disks were manufactured from titanium (Ti-6Al-4V) alloy. A NASA Glenn Research Center developed probabilistic computer code Probable Cause was used to predict disk life and reliability. A material-life factor A was determined for titanium (Ti-6Al-4V) alloy based upon fatigue disk data and successfully applied to predict the life of the disks as a function of speed. A comparison was made with the currently used life prediction method based upon crack growth rate. Applying an endurance limit to the computer code did not significantly affect the predicted lives under engine operating conditions. Failure location prediction correlates with those experimentally observed in the LCF tests. A reasonable correlation was obtained between the predicted disk lives using the Probable Cause code and a modified crack growth method for life prediction. Both methods slightly overpredict life for one disk group and significantly under predict it for the other

A novel method to evaluate gamma camera rotational uniformity and sensitivity variation

Kappadath, S.C., Erwin, W.D. and Wendt, R.E., III (2009), A novel method to evaluate gamma camera rotational uniformity and sensitivity variation. Med. Phys., 36: 1947-1955. https://doi.org/10.1118/1.3125642https://openworks.mdanderson.org/mdacc_imgphys_pubs/1007/thumbnail.jp

Observed intercamera variability in clinically relevantperformance characteristics for Siemens Symbia gammacameras

This is the peer reviewed version of the following article: Kappadath SC, Erwin WD, Wendt RE 3rd. Observed inter-camera variability of clinically relevant performance characteristics for Siemens Symbia gamma cameras. J Appl Clin Med Phys. 2006;7(4):74-80. Published 2006 Nov 28., which has been published in final form at doi:10.1120/jacmp.v7i4.2376. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.https://openworks.mdanderson.org/mdacc_imgphys_pubs/1009/thumbnail.jp

Optimal 57Co Flood Source Activity and Acquisition Time for Lymphoscintigraphy Localization Images

Martha V. Mar, Renee L. Dickinson, William D. Erwin, Richard E. Wendt. Optimal 57Co Flood Source Activity and Acquisition Time for Lymphoscintigraphy Localization Images. Journal of Nuclear Medicine Technology Jun 2008, 36 (2) 82-87; DOI: 10.2967/jnmt.107.047043https://openworks.mdanderson.org/mdacc_imgphys_pubs/1008/thumbnail.jp

Brief Note A Radiocarbon-Dated Mammoth Site, Marion County, Ohio

Author Institution: Ohio Division of Geological Survey; Ohio Historical Society; Ohio State University-Mario

A preclinical investigation of the saturation and dosimetry of 153Sm-DOTMP as a bone-seeking radiopharmaceutical

Simón J, Frank RK, Crump DK, Erwin WD, Ueno NT, Wendt RE. A preclinical investigation of the saturation and dosimetry of 153Sm-DOTMP as a bone-seeking radiopharmaceutical. Nuclear Medicine and Biology. 2012/08/01/ 2012;39(6):770-776. doi:https://doi.org/10.1016/j.nucmedbio.2011.12.015https://openworks.mdanderson.org/mdacc_imgphys_pubs/1006/thumbnail.jp

Hybrid Modality Fusion of Planar Scintigrams and CT Topograms to Localize Sentinel Lymph Nodes in Breast Lymphoscintigraphy: Technical Description and Phantom Studies

Lymphoscintigraphy is a nuclear medicine procedure that is used to detect sentinel lymph nodes (SLNs). This project sought to investigate fusion of planar scintigrams with CT topograms as a means of improving the anatomic reference for the SLN localization. Heretofore, the most common lymphoscintigraphy localization method has been backlighting with a 57Co sheet source. Currently, the most precise method of localization through hybrid SPECT/CT increases the patient absorbed dose by a factor of 34 to 585 (depending on the specific CT technique factors) over the conventional 57Co backlighting. The new approach described herein also uses a SPECT/CT scanner, which provides mechanically aligned planar scintigram and CT topogram data sets, but only increases the dose by a factor of two over that from 57Co backlighting. Planar nuclear medicine image fusion with CT topograms has been proven feasible and offers a clinically suitable compromise between improved anatomic details and minimally increased radiation dose

In Tribute: M. Katherine B. Darmer

The editors of the Chapman Law Review respectfully dedicate this issue to Professor M. Katherine B. Darmer