Acoustic Leak Detection for District Heating Systems (open access)

Acoustic Leak Detection for District Heating Systems

An acoustic leak detection facility was completed and used to evaluate the capability of piezoelectric sensors, accelerometers, and capacitance microphones to detect and locate gas and water leaks in underground district heating and cooling (DHC) piping. Leak detection sensitivity and location capabilities for DHC systems were estimated from laboratory data and from data obtained from the underground DH system in Scranton, Pennsylvania, where acoustic background noise levels and acoustic signals from field-induced steam leaks were acquired. Acoustic detection of leaks with flow rates of less than 10 gpm is possible at a distance of several hundred meters, with a location accuracy of a few meters. Although steam leaks of comparable mass loss can be detected over a similar range with transducers mounted on the pipe outer wall, location accuracy of a few meters over this range may only be possible with transducers in direct contract with the steam. Intrusive sensors may also be necessary to detect and locate leaks in plastic pipe.
Date: February 1988
Creator: Kupperman, D. S. & Karvelas, D. E.
System: The UNT Digital Library
Characteristics of the 7-GeV Advanced Photon Source : a Guide for Users (open access)

Characteristics of the 7-GeV Advanced Photon Source : a Guide for Users

In this document we present the characteristics of the electromagnetic radiation from various types of sources on the 7-GeV Advanced Photon Source (APS) storage ring. The sources include bending magnets, undulators, and wigglers. The characteristics are compared with those of other synchrotron sources when operated at their design specifications. The influence of positron beam size on the on-axis brilliance is discussed, along with the power distribution from these sources. The goal of this document is to provide users with enough information on the characteristics of radiation from the APS storage ring so that experiments can be efficiently planned.
Date: February 1988
Creator: Shenoy, G. K.; Viccaro, P. J. & Mills, Dennis M.
System: The UNT Digital Library
Portable Implementation of a Generic Exponential Function in Ada (open access)

Portable Implementation of a Generic Exponential Function in Ada

By presenting a provably accurate implementation of the exponential function, we illustrate that an accurate and portable elementary-function library can be implemented in Ada.
Date: February 1988
Creator: Tang, Ping Tak Peter
System: The UNT Digital Library
Practical Issues Relating to the Internal Database Predicates in an OR-Parallel Prolog: Extensions and Useful Hacks (open access)

Practical Issues Relating to the Internal Database Predicates in an OR-Parallel Prolog: Extensions and Useful Hacks

This technical report is being written to document and explain some of the insights the authors have gained during the implementation of two OR-parallel Prolog systems for shared-memory multiprocessors. We have been quite amazed by how much power and functionality can be achieved through the implementation of just a few primitive predicates. We introduce a few relatively trivial predicates which allow one to implement versions of findall/3, bagof/3, and setof/3 for the a multiprocessor environment. Then we show how these predicates can be used to implement AND-parallelism. Finally, we illustrate their use for implementing a limited notion of streams, and how such streams can be used to create a compiler that achieves excellent speedups for multiprocessors with a limited number of processors.
Date: February 1988
Creator: Carlsson, Mats; Danhof, Ken & Overbeek, Ross
System: The UNT Digital Library
Reaction of Glass During Gamma Irradiation in a Saturated Tuff Environment, Part 3: Long-Term Experiments at 1x10^4 Rad/Hour (open access)

Reaction of Glass During Gamma Irradiation in a Saturated Tuff Environment, Part 3: Long-Term Experiments at 1x10^4 Rad/Hour

Report on experiments to assess the importance of radiation effects on waste glass corrosion. This third part contains a description of the experiments, results, and discussion, with conclusions and related appendices.
Date: February 1988
Creator: Abrajano, Teofilo Aniag; Bates, John K.; Gerding, Thomas J. & Ebert, William L.
System: The UNT Digital Library
Speciation of Radionuclides in Natural Groundwaters, Annual Report: October 1986 through September 1987 (open access)

Speciation of Radionuclides in Natural Groundwaters, Annual Report: October 1986 through September 1987

Two ultrasensitive laser techniques, laser photoacoustic spectroscopy (LPAS) and laser-induced fluorescence (LIF), are being developed for the detection and speciation of trace levels of actinides in solutions typical of those expected in a high-level waste repository. An LPAS system was set up for these studies. Experiments were carried out to determine the detection limits of plutonium and americium in solution. Concurrently with the LPAS work, LIF studies were carried out on uranyl ion and curium in solution.
Date: February 1988
Creator: Doxtader, M. M.; Beitz, J. V.; Reed, Donald Timothy & Bates, John K.
System: The UNT Digital Library
A Systematic Analysis of the Spectra of the Lanthanides Doped into Single Crystal LaF₃ (open access)

A Systematic Analysis of the Spectra of the Lanthanides Doped into Single Crystal LaF₃

Report of the correlations between experimental transition energies and computed level structures.
Date: February 1988
Creator: Carnall, W. T.; Goodman, G. L.; Rajnak, K. & Rana, R. S.
System: The UNT Digital Library