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Acoustic microscopy with mixed-mode transducers
The new amplitude-phase acoustic microscope is versatile; it operates in a wide frequency range 1--200 MHz, with selection of longitudinal, shear, and mixed modes. This enables it to be used in many NDE applications for different kinds of materials. Besides the application examples presented in this paper (bulk defect imaging of lossy materials or at deep locations; leads of IC chip in epoxy package; amplitude images of surface crack on Si nitride ball bearing; thin Au film on quartz), this system can also be applied for residual stress and anisotropy mapping with high accuracy and good spatial resolution. 7 refs, 6 figs.
Date:
December 31, 1988
Creator:
Chou, C. H.; Parent, P. & Khuri-Yakub, B. T.
Object Type:
Article
System:
The UNT Digital Library
Adaptive significance of root grafting in trees
Root grafting has long been observed in forest trees but the adaptive significance of this trait has not been fully explained. Various authors have proposed that root grafting between trees contributes to mechanical support by linking adjacent root systems. Keeley proposes that this trait would be of greatest advantage in swamps where soils provide poor mechanical support. He provides as evidence a greenhouse study of Nyssa sylvatica Marsh in which seedlings of swamp provenance formed between-individual root grafts more frequently than upland provenance seedlings. In agreement with this within-species study, Keeley observed that arid zone species rarely exhibit grafts. Keeley also demonstrated that vines graft less commonly than trees, and herbs never do. Since the need for mechanical support coincides with this trend, these data seem to support his model. In this paper, the authors explore the mechanisms and ecological significance of root grafting, leading to predictions of root grafting incidence. Some observations support and some contradict the mechanical support hypothesis.
Date:
December 31, 1988
Creator:
Loehle, C. & Jones, R.
Object Type:
Report
System:
The UNT Digital Library
Advanced alternate planar geometry solid oxide fuel cells. Third interim quarterly technical progress report, July 1, 1988--September 30, 1988
The following Ceramatec tasks are reported: electrolyte development and fabrication, edge seal development/fabrication, electrode, and interconnector. The following IGT tasks are reported: cell design analysis, and program liaison and test facility preparation.
Date:
December 31, 1988
Creator:
Prouse, D.; Elangovan, S.; Khandkar, A.; Donelson, R. & Marianowski, L.
Object Type:
Report
System:
The UNT Digital Library
Advanced Water-Cooled Phosphoric Acid Fuel Cell Development. Quarterly technical progress report No. 5, July--September 1988
The initial conceptual design configuration was completed. Baseline on-site electrodes were tested at electric utility conditions in 2 x 2 inch cells. GSB-18P cathodes were fabricated. Design of small area development stack was initiated and long lead time items ordered. Molded cooler thermal cycling tests were initiated. Equipment to evaluate alternative manifold coating processes and materials were procured.
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Analysis of Momentum and Impurity Confinement in TFTR. [Annual Report, 1989]
The accomplishments to date of this research in collaboration with PPPL are the following: (1) full access capability to the TFTR data system has been achieved at Georgia Tech; (2) procedures to enable PPPL codes to be used in conjunction with ``in house`` programs for data analysis have been developed; (3) evaluation of the experimental data has been performed; and (4) a preliminary comparison of several momentum transport theories against experimental measurements has been performed.
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
The Annual Report of the California Energy Company, 1988
This is the annual report of the California Energy Company
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Annual site environmental report for calendar year 1988
The Western Area Power Administration (Western) has established a formal environmental protection, auditing, monitoring, and planning program which has been in effect since 1978. The significant environmental projects and issues Western was involved with in 1988 are discussed in this annual site environmental report. It is written to demonstrate the nature and effectiveness of the environmental protection program. Western is responsible for the operation and maintenance of 16,376 miles of transmission lines, 254 substations, and various appurtenant power facilities in the above geographic areas. Western also is responsible for planning, construction, and operation and maintenance of additional Federal transmission facilities that may be authorized in the future. There is a combined total of 51 hydroelectric power generating plants in the service areas. Additionally, Western markets the US entitlement from the large Navajo coal-fired plant near Page, Arizona, and power generated at a wind farm in Wyoming. The Department of Energy requires the preparation of an annual site environmental report. Because Western has numerous facilities located in these states, this report was written to address the environmental activities in all of the facilities as one site.
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Application of Quaternary Phase Diagrams to Compound Semiconductor Processing. Progress Report, April 1, 1988--December 31, 1988
This paper considers the application of quaternary phase diagrams to understanding and predicting the behavior of II-VI thin film interfaces in photovoltaic devices under annealing conditions. Examples, listed in a table, include semiconductor/insulator/semiconductor (SIS) layered structures, II-VI/II-VI and III-V/II-VI epitaxial heterojunctions and oxidation of ternary compounds. Solid solubility is taken into account for quaternary phase diagrams of semiconductor systems. Using free energies of formation, a method to calculate the quaternary phase diagrams was developed. The Ga-As-II-VI and Cd-Te-Zn-O phase diagrams are reviewed as examples of quaternary phase diagrams without and with solid solubility.
Date:
December 31, 1988
Creator:
Schwartzman, A.
Object Type:
Report
System:
The UNT Digital Library
Application of rock melting to construction of storage holes for nuclear waste
Rock melting technology can provide in-situ glass liners in nuclear waste package emplacement holes to reduce permeability and increase borehole stability. Reduction of permeability would reduce the time and probability of groundwater contacting the waste packages. Increasing the stability of the storage boreholes would enhance the retrievability of the nuclear waste packages. The rock melting hole forming technology has already been tested in volcanic tuff similar to the geology at the proposed nuclear waste repository at Yucca Mountain, Nevada. 6 refs., 5 figs., 2 tabs.
Date:
December 31, 1988
Creator:
Neudecker, J.W. Jr.
Object Type:
Article
System:
The UNT Digital Library
Applications of interference theory to single failure modes
REL02 is a computer code which provides a designer and analyst with a mathematical tool to calculate the expected failure probability under a variety of assumptions of the form of two overlapping probability distributions. This code has extended the solutions of closed-form calculations to the applications involving truncated normal and Weibull distribution as well as the uniform distribution. These distributions have been found to describe the variations which exist in (a) analytical predictions of stress parameters and (b) accumulated test results of strength data. REL02 has been written to calculate the general failure probability based on the interaction of a specified applied stress distribution and a known failure strength distribution. This program has been useful to quantitatively evaluate the adequacy of design margins and the acceptability of discrepant fabrication conditions. Examples of the application of this code to engineering problems are presented.
Date:
December 31, 1988
Creator:
Rauth, D. R. & Lusardi, D. J.
Object Type:
Article
System:
The UNT Digital Library
Arctic hydrology and meteorology. Annual report
The behavior of arctic ecosystems is directly related to the ongoing physical processes of heat and mass transfer. Furthermore, this system undergoes very large fluctuations in the surface energy balance. The buffering effect of both snow and the surface organic soils can be seen by looking at the surface and 40 cm soil temperatures. The active layer, that surface zone above the permafrost table, is either continually freezing or thawing. A large percentage of energy into and out of a watershed must pass through this thin veneer that we call the active layer. Likewise, most water entering and leaving the watershed does so through the active layer. To date, we have been very successful at monitoring the hydrology of Imnavait Creek with special emphasis on the active layer processes. The major contribution of this study is that year-round hydrologic data are being collected. An original objective of our study was to define how the thermal and moisture regimes within the active layer change during an annual cycle under natural conditions, and then to define how the regime will be impacted by some imposed terrain alteration. Our major analysis of the hydrologic data sets for Imnavait Creek have been water balance …
Date:
December 31, 1988
Creator:
Kane, D. L.
Object Type:
Report
System:
The UNT Digital Library
Assessment of seismic hazards at Yucca Mountain
During the preclosure time period (approximately 100 yr), the prospective geologic repository at Yucca Mountain must provide for public and worker radiological safety and retrievability of emplaced waste. During the postclosure period (10,000 yr), the repository must ensure that cumulative radionulclide releases to the accessible environment comply with EPA release limits. Substantially complete containment must be provided by the waste packages for 300-1000 yr. All of these functions must be maintained should a severe seismic event occur and must be achieved with reasonably available technology. The seismic phenomena of interest for the preclosure period are vibratory ground motion from a nearby earthquake or underground nuclear explosion (UNE), faulting beneath surface facilities that are important to safety, and faulting in underground areas of emplaced waste. For the postclosure period, earthquake ground motion, underground faulting, and seismically induced adverse changes in hydrologic conditions have been identified as the most important seismic phenomena to be characterized. The NNWSI Project Site Charcterization Plan describes a number of seismic parameters that are needed for repository design or performance assessment, along with tentative goals for each parameter. Key parameters, goals and current assessments, all subject to change as site characterization progresses, are summarized in this report. …
Date:
December 31, 1988
Creator:
King, J. L.; Frazier, G. A. & Grant, T. A.
Object Type:
Article
System:
The UNT Digital Library
[Atmospheric transport and dispersion of pollutants and related meteorological studies]
None
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
[Atom-counting standards and Doppler-free resonance ionization mass spectroscopy]. [Progress report]
This program has two components: quantification and improvement of ultrasensitive techniques, and development of isotopic ratio standards in the ultrasensitive range of 10{sup {minus}10} and lower. Data sheets were developed.
Date:
December 31, 1988
Creator:
Hutchinson, J. M. R. & Inn, K. G. W.
Object Type:
Report
System:
The UNT Digital Library
Automated dimensional analysis using a light-sectioning microscope
A computer vision system has been integrated with a modified light-sectioning microscope for quality control and inspection of a machined part whose critical dimensions are 30 to 300 {mu}m. Height measurements were determined by analysis of the projected light-section line. Transverse measurements were made using the microscope in a traditional configuration with illumination from selected elements of an external LED ring array. The light section irradiance was under computer control to accommodate the spatial variations in surface reflectance whose dynamic range exceeded that of the vision system. Part features are located by the vision system. Edges and line centers are then measured to sub-pixel resolution with a gray-level analysis algorithm. This paper describes the design and operation of this system. Details of the measurement process and analysis algorithms are provided.
Date:
December 31, 1988
Creator:
Loomis, J.; Lightman, A.; Poe, A. & Caldwell, R.
Object Type:
Article
System:
The UNT Digital Library
Calculation of radiation dose rates from a spent nuclear fuel shipping cask
Radiation doses from a spent nuclear fuel cask are usually from various phases of operations during handling, shipping, and storage of the casks. Assessment of such doses requires knowledge of external radiation dose rates at various locations surrounding a cask. Under current practices, dose rates from gamma photons are usually estimated by means of point- or line-source approaches incorporating the conventional buildup factors. Although such simplified approaches may at times be easy to use, their accuracy has not been verified. For example, those simplified methods have not taken into account influencing factors such as the geometry of the cask and the presence of the ground surface, and the effects of these factors on the calculated dose rates are largely unknown. Moreover, similar empirical equations for buildup factors currently do not exist for neutrons. The objective of this study is to use a more accurate approach in calculating radiation dose rates for both neutrons and gamma photons from a spent fuel cask. The calculation utilizes the more sophisticated transport method and takes into account the geometry of the cask and the presence of the ground surface. The results of a detailed study of dose rates in the near field (within 20 …
Date:
December 31, 1988
Creator:
Chen, S. Y. & Yuan, Y. C.
Object Type:
Article
System:
The UNT Digital Library
Calorimetry exchange program. Annual report, 1988
The goals of the Calorimetry Sample Program are: 1. Discuss measurement differences, 2. Review and improve analytical measurements and methods, 3. Discuss new measurement capabilities, 4. Provide data to DOE on measurement capabilities to evaluate shipper- receiver differences, 5. Provide characterized or standard materials as necessary for exchange participants, 6. Provide a measurement control program for plutonium analysis. A sample of PuO{sub 2} powder is available at each participating site for NDA measurement, including either or both calorimetry and high-resolution gamma-ray spectroscopy, the elements which are typically combined to provide a calorimetric assay of plutonium. The facilities measure the sample as frequently and to the level of precision which they desire, and then submit the data to the Exchange for analysis. Statistical tests are used to evaluate the data and to determine if there are significant differences from accepted values for the exchange or from data previously reported by that facility. Data included in this report is a compilation of all exchange data received in 1988. Since a large number of data points were recorded, a change was made to the analysis method to account for the uncertainty in the accepted values.
Date:
December 31, 1988
Creator:
Lyons, J.E.
Object Type:
Report
System:
The UNT Digital Library
[Characterization and supply of coal based fuels]. Quarterly technical report, February 1, 1988--April 30, 1988
Contract objectives are as follows: Develop fuel specifications to serve combustor requirements; Select coals having appropriate compositional and quality characteristics as well as an economically attractive reserve base; Provide quality assurance for both the parent coals and the fuel forms; and deliver premium coal-based fuels to combustor developers as needed for their contract work. Progress is described.
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Characterization and supply of coal-based fuels. Quarterly technical report, May 1, 1988--July 31, 1988
Contract objectives are as follows: Develop fuel specifications to serve combustor requirements; select coals having appropriate compositional and quality characteristics as well as an economically attractive reserve base; provide quality assurance for both the parent coals and the fuel forms; and deliver premium coal-based furls to combustor developers as needed for their contract work.
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
[Characterization and supply of coal based fuels]. Quarterly technical report, November 1, 1987--January 31, 1988
The capability to produce significant quantities of coal based fuels cannot be supported in the current economic and energy use situation. Once these pieces of experience and information begin to fall into place, the market driven needs will more clearly identify the suite of coals that will satisfy the markets and the performance requirements (i.e., cost, maintenance, energy efficiency, environmental). For now, it is important to provide sufficient quantities of surrogate fuels to enable development testing to proceed. To serve as surrogate fuels, the fuels should have chemical and physical characteristics (ash, sulfur, volatiles, fusion temperature, heat content, particle size distribution, slurry formulation, etc.) that are consistent with projected performance and environmental standards. In addition, these surrogates are to be produced using readily available conventional types of cleaning and processing so as to not promote a particular fuel technology or create a reliability on an uncertain fuel technology. The analysis of fuel needs, the selection of candidate coals, the characterization and supply in this contract are to be accomplished with the above in mind. Following the fuels and combustor development activities that this supply contract will support, it is expected that additional optional candidate coals will become evident based on …
Date:
December 31, 1988
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
[A clinical trial of neutron capture therapy for brain tumors]. Technical progress report 1988
This report describes progress made in refining of neutron-induced alpha tract autoradiography, in designing epithermal neutron bean at MITR-II and in planning treatment dosimetry using Monte Carlo techniques.
Date:
December 31, 1988
Creator:
Zamenhof, R. G.
Object Type:
Report
System:
The UNT Digital Library
Determination of local radiative properties in coal-fired flames. Technical progress report, September 15, 1987--September 15, 1988
Recently, an extensive, in-depth review of the modeling of radiation heat transfer in combustion chambers has been prepared (Viskanta and Menguc, 1987); therefore, there is no need to repeat that material here. It is already known that the most important missing link in the prediction of radiation heat transfer in combustion systems is the lack of detailed information about the optical and physical properties of combustion products (Viskanta and Menguc, 1987). The purpose of this research is to determine the radiative properties of coal particles. Considering the uncertainty in the fundamental optical and physical properties of coal particles, such as complex index of refraction, size, size distribution, and shape, it is difficult to predict the radiative properties of particles using available analytical methods, such as Lorenz-Mie theory. For a better understanding of radiation and radiation/combustion or radiation/turbulence interactions, it is preferable to determine the radiative properties in situ.
Date:
December 31, 1988
Creator:
Menguec, M. P.; Agarwal, B.; Bush, M.; Dsa, D. & Subramaniam, S.
Object Type:
Report
System:
The UNT Digital Library
Development and process evaluation of improved Fischer-Tropsch slurry catalysts. Quarterly technical progress report, 1 July--30 September 1988
The objective of this contract is to develop a consistent technical data base on the use of iron-based catalysts in Fischer-Tropsch (F-T) synthesis reactions. This data base will be developed to allow the unambiguous comparison of the performance of these catalysts with each other and with state-of-the-art iron catalyst compositions. Particular attention will be devoted to generating reproducible kinetic and selectivity data and to developing reproducible improved catalyst compositions.
Date:
December 31, 1988
Creator:
Withers, H. P.; Bukur, D. B. & Rosynek, M. P.
Object Type:
Report
System:
The UNT Digital Library
Development and process evaluation of improved Fischer-Tropsch slurry catalysts. Quarterly technical progress report, 1 October--31 December 1988
The objective of this contract is to develop a consistent technical data base on the use of iron-based catalysts in Fischer-Tropsch (FT) synthesis reactions. This data base will be developed to allow the unambiguous comparison of the performance of these catalysts with each other and with state-of-the-art iron catalyst compositions. Particular attention will be devoted to generating reproducible kinetic and selectivity data and to developing reproducible improved catalyst compositions.
Date:
December 31, 1988
Creator:
Withers, H. P.; Bukur, D. B. & Rosynek, M. P.
Object Type:
Report
System:
The UNT Digital Library