Bureau of Reclamation, Acquisition Operations Group, Code D-7810, Denver Federal Center, PO Box 25007, Denver CO 80225

B -- RELIABILITY OF ACOUSTIC TRAVEL TIME TOMOGRAPHY SOL 1425-97-SQ-81-92046 DUE 052897 POC Evelyn M. Tate 303-236-8040 X228 WEB: Bureau of Reclamation Denver Office Acquisition Home Page AAms Current Solicitation Listing, http://www.usbr.gov/aamsden/AAMSsol.html. E-MAIL: Contracting Officer's E-Mail Address, etate@do.usbr.gov. Concerns having the ability to furnish the following services are qrequested to give written notification, including a telephone number for a POC to the Acquisition office listed in this notice within 15 calendar days from the date of synopsis. The Bureau of Reclamation has a requirement for Reliability of Acoustic Travel Time Tomography. It is Reclamation's belief that the University of Denver Research Institute is the only firm capable of providing this service based on the following facts: The reliability of Acoustic Travel Time Tomography will be determined by a combination of both field and laboratory testing. A sonic nondestructive evaluation method will be used at Barker Dam, based on a concept of "Acoustic Travel Time Tomography" developed in a collaboration (patent pending) between the Bureau of Reclamation and The University of Denver Research Institute (under the auspices of the University of Denver Office of Sponsored Programs). Signals will be collected using twenty receivers placed on a single cross section of the dam. In order to visualize the results, software for tomographic velocity reconstruction will be developed for a PC. This software will then be used to analyze the collected sonic signals, and reconstruct the section and assess its integrity. Probability of detection curves will be developed in the laboratory using test blocks cast by Reclamation. This is not a formal solicitation. However, concerns that respond shall provide detailed data concerning their capabilities and may request to receive a copy of the solicitation when and if it becomes available. This notice may represent the only official notice of such a solicitation. (1) Design of the field experiments at Barker Dam-The project team, in coordination with Bureau of Reclamation staff, will visit Barker Dam, and select the cross section plan to be analyzed, the source locations, the detectors' locations, and the testing procedure to be used. (2) Software development-Develop and integrate computer software for a low-cost PC. It will utilize tomographic velocity reconstruction of a cross section of the dam. This will be based on analysis of first arrival of the signals. The program will be tested against known solutions in order to assess its performance. The images generated from the actual measurements will then be used to visualize region of anomaly in the structure. (3) Transducers deployment and testing at Barker Dam-Sonic signals will be generated by Reclamation, and twenty channels will collect the transmitted signals via twenty sensors (detectors). All sources and receivers will be placed along the same cross section of the dam. A detailed scheme for sensor placement will be developed in coordination with Bureau of Reclamation staff. The combination of sources, each with twenty detected signals will be used. The collected signals will be digitized and stored in a PC, to be used for reconstruction of the tomographic image of the chosen cross section. (4) Processing of the collected field data-The digitized data will be entered into the tomographic reconstruction program developed in Step 2, and an image of the cross section will be generated. (5) Reliability Measurements-The reliability of the 20 channel system will be determined in the laboratory at Reclamation. Reclamation will design and fabricate a test block (or blocks) containing laminar defect features with a range of sizes. The test block(s) will be tested using both a James V-meter and the ATTT system to enable estimates for detection sensitivity to be made, and hence an estimate for the reliability of inspection using ATTT. Enough data will be taken to develop probability of detection curves. (5) Reporting-The contractor will deliver three copies of a project report. It will include samples of the collected signals, and reconstructed images of the tested section of the dam. (0133)

Loren Data Corp. http://www.ld.com (SYN# 0018 19970516\B-0006.SOL)