Aluminum-fly ash metal matrix composites for automotive parts. [Reports for October 1 to December 1998, and January 31 to March 31, 1999] (open access)

Aluminum-fly ash metal matrix composites for automotive parts. [Reports for October 1 to December 1998, and January 31 to March 31, 1999]

Some highlights are: (1) Material development, process development, and part validation are occurring simultaneously on a fast track schedule. (2) Prior project activity has resulted in a program emphasis on three components--manifolds, mounting brackets, and motor mounts; and three casting techniques--squeeze casting, pressure die casting, and sand casting. (3) With the project focus, it appears possible to offer manifolds and mounting brackets for automotive qualification testing on a schedule in line with the PNGV Year 2004 goal. (4) Through an iterative process of fly ash treatment, MMC ingot preparation, foundry process refinement, and parts production, both foundries (Eck Industries and Thompson Aluminum Casting Company) are addressing the pre-competitive issues of: (a) Optimum castability with fly ash shapes and sizes; (b) Best mechanical properties derived from fly ash shapes and sizes; (c) Effective fly ash classification processes; (d) Mechanical properties resulting from various casting processes and fly ash formulations. Eck and TAC continued experiments with batch ingot provided by both Eck and the University of Wisconsin at Milwaukee. Castings were run that contained varying amounts of fly ash and different size fractions. Components were cast using cenosphere material to ascertain the effects of squeeze casting and to determine whether the pressure …
Date: April 21, 1999
Creator: Weiss, David; Purgert, Robert; Rhudy, Richard & Rohatgi, P.
Object Type: Report
System: The UNT Digital Library
Azo Dyes and Their Interfacial Activity: Implications for Multiphase Flow Experiments (open access)

Azo Dyes and Their Interfacial Activity: Implications for Multiphase Flow Experiments

Interfacial effects play an important role in governing multiphase fluid behavior in porous media (Neustadter 1984; Tuck et al. 1988). For instance, several dimensionless numbers have been developed to express important force ratios applicable to multiphase flow in porous media (Morrow and Songkran 1981; Chatzis and Morrow 1984; Wardlaw 1988; Pennell et al. 1996; Dawson and Roberts 1997). These force ratios emphasize the importance of interfacial properties. Our objectives are to provide chemical information regarding the dyes commonly used in multiphase flow visualization studies and to show the surface chemistry effects of the most commonly used dye, Sudan IV, in the tetrachloroethylene (PCE)-water-glass system
Date: April 21, 1999
Creator: Tuck, David M.
Object Type: Article
System: The UNT Digital Library
A Criticality Safety Study on Storing Unirradiated Cintichem-Type Targets at Sandia National Laboratories (open access)

A Criticality Safety Study on Storing Unirradiated Cintichem-Type Targets at Sandia National Laboratories

This criticality safety analysis is performed to determine the effective multiplication factor (k{sub eff}) for a storage cabinet filled with unirradiated Cintichem-type targets. These targets will be used to produce {sup 99}Mo at Sandia National Laboratories and will be stored on-site prior to irradiation in the Annular Core Research Reactor. The analysis consisted of using the Monte Carlo code MCNP (Version 4A) to model and predict the k{sub eff} for the proposed dry storage configuration under credible loss of geometry and moderator control. Effects of target pitch, non-uniform loading, and target internal/external flooding are evaluated. Further studies were done with deterministic methods to verify the results obtained from MCNP and to obtain a clearer understanding of the parameters affecting system criticality. The diffusion accelerated neutral particle transport code ONEDANT was used to model the target in a one-dimensional, infinite half-slab geometry and determine the critical slab thickness. Hand calculations were also completed to determine the critical slab thickness with modified one-group, and one-group, two region approximations. Results obtained from ONEDANT and the hand calculations were compared to applicable cases in a commonly used criticality safety analysis handbook. Overall, the critical slab thicknesses obtained in the deterministic analysis were much larger …
Date: April 21, 1999
Creator: Romero, D. J.; Parma, E. J. & Busch, R. D.
Object Type: Article
System: The UNT Digital Library
Crop Insurance: Further Actions Could Strengthen Program's Financial Soundness (open access)

Crop Insurance: Further Actions Could Strengthen Program's Financial Soundness

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the Department of Agriculture's (USDA) federal crop insurance program, focusing on whether USDA: (1) has set adequate insurance rates to achieve the legislative requirement of actuarial soundness; (2) appropriately reimburses participating crop insurance companies for their administrative costs; (3) can deliver catastrophic crop insurance at less cost to the government than private insurance companies; and (4) has established methodologies in the revenue insurance plans that set sound premium rates."
Date: April 21, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Defense Acquisition: Historical Insights Into Navy Ship Leasing (open access)

Defense Acquisition: Historical Insights Into Navy Ship Leasing

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the Navy's decisions in the early 1970s and early 1980s to lease Sealift Tankers, Maritime Prepositioning Ships, and T-5 replacement tankers, and more recently, Chouest specialized support vessels, focusing on the: (1) basis and support for the Navy's decisions to lease rather than purchase these vessels; (2) concerns that surrounded the decisions; and (3) legislative and regulatory changes that have been implemented that will influence future lease versus purchase decisions."
Date: April 21, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Defense Reform Initiative: Organization, Status, and Challenges (open access)

Defense Reform Initiative: Organization, Status, and Challenges

A chapter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reported on: (1) actions taken through the Defense Reform Initiative (DRI) management structure to facilitate achieving the program's objective; and (2) progress the Department of Defense (DOD) made in implementing individual reform initiatives."
Date: April 21, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Demonstration Integrated Knowledge-Based System for Estimating Human Error Probabilities (open access)

Demonstration Integrated Knowledge-Based System for Estimating Human Error Probabilities

Human Reliability Analysis (HRA) is currently comprised of at least 40 different methods that are used to analyze, predict, and evaluate human performance in probabilistic terms. Systematic HRAs allow analysts to examine human-machine relationships, identify error-likely situations, and provide estimates of relative frequencies for human errors on critical tasks, highlighting the most beneficial areas for system improvements. Unfortunately, each of HRA's methods has a different philosophical approach, thereby producing estimates of human error probabilities (HEPs) that area better or worse match to the error likely situation of interest. Poor selection of methodology, or the improper application of techniques can produce invalid HEP estimates, where that erroneous estimation of potential human failure could have potentially severe consequences in terms of the estimated occurrence of injury, death, and/or property damage.
Date: April 21, 1999
Creator: Auflick, Jack L.
Object Type: Article
System: The UNT Digital Library
Dialkylenecarbonate-Bridged Polysilsesquioxanes. Hybrid Organic Sol-Gels with a Thermally Labile Bridging Group (open access)

Dialkylenecarbonate-Bridged Polysilsesquioxanes. Hybrid Organic Sol-Gels with a Thermally Labile Bridging Group

In this paper, we introduce a new approach for altering the properties of bridged polysilsesquioxane xerogels using post-processing modification of the polymeric network. The bridging organic group contains latent functionalities that can be liberated thermally, photochemically, or by chemical means after the gel has been processed to a xerogel. These modifications can produce changes in density, volubility, porosity, and or chemical properties of the material. Since every monomer possesses two latent functional groups, the technique allows for the introduction of high levels of functionality in hybrid organic-inorganic materials. Dialkylenecarbonate-bridged polysilsesquioxane gels were prepared by the sol-gel polymerization of bis(triethoxysilylpropyl)carbonate (1) and bis(triethoxysilylisobutyl)-carbonate (2). Thermal treatment of the resulting non-porous xerogels and aerogels at 300-350 C resulted in quantitative decarboxylation of the dialkylenecarbonate bridging groups to give new hydroxyalkyl and olefinic substituted polysilsesquioxane monolithic xerogels and aerogels that can not be directly prepared through direct sol-gel polymerization of organotrialkoxysilanes.
Date: April 21, 1999
Creator: Loy, Douglas A.; Beach, James V.; Baugher, Brigitta M.; Assink, Roger A.; Shea, Kenneth J.; Tran, Joseph et al.
Object Type: Article
System: The UNT Digital Library
Drug Control: INS and Customs Can Do More To Prevent Drug-Related Employee Corruption (open access)

Drug Control: INS and Customs Can Do More To Prevent Drug-Related Employee Corruption

Testimony issued by the General Accounting Office with an abstract that begins "GAO discussed the threat of corruption to Immigration and Naturalization Service (INS) and Customs Service employees along the Southwest Border, focusing on: (1) the extent to which INS and the Customs Service have and comply with policies and procedures for ensuring employee integrity; (2) an identification and comparison of the Departments of Justice's and the Treasury's organizational structures, policies, and procedures for handling allegations of drug-related employee misconduct and whether the policies and procedures are followed; (3) an identification of the types of illegal drug-related activities in which INS and Customs employees on the Southwest Border have been convicted; and (4) the extent to which lessons learned from corruption cases closed in fiscal years 1992 through 1997 have led to changes in policies and procedures for preventing the drug-related corruption of INS and Customs employees."
Date: April 21, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Effect of Substrate Composition on the Piezoelectric Response of Reactively Sputtered AlN Thin Films (open access)

Effect of Substrate Composition on the Piezoelectric Response of Reactively Sputtered AlN Thin Films

Deposition parameters were found to have a marked effect on piezoelectric response of reactive radio frequency (RF) sputtered AlN thin films. The authors observed peizoelectric response values ranging from {minus}3.5 to +4.2 pm/V for 1 {micro}m thick AlN films deposited onto Ti/Ru electrode stacks. An investigation of the effects of deposition parameters, in particular the nature of the Ru/AlN interface, was conducted. The lag time between deposition of adjacent thin film layers appeared to have the greatest affect on the value of the piezoelectric response. This suggests that chemical reaction occurring on the Ru thin film surface is responsible for changing an important thin film property such as dipole orientation within the overlying AlN thin film.
Date: April 21, 1999
Creator: Clem, P. G.; Dimos, D. B.; Gonzales, D. M.; Ruffner, J. A. & Tuttle, B. A.
Object Type: Article
System: The UNT Digital Library
Evaluation of Arizona's enhanced I/M program (open access)

Evaluation of Arizona's enhanced I/M program

MOBILE5 slightly overpredicts initial reductions in CO and HC, and dramatically overpredicts initial reductions in NOx. About one-third of the vehicles that fail initial I/M testing do not complete the I/M program. Only a small portion of these receive a waiver. Initial I/M repair effectiveness as measured by remote sensing is only half of that as measured by IM240. Possible causes are sensitivity to operating mode, and how long after repair emissions are measured. 37% of the vehicles that initially fail and eventually pass in 1995 fail again in 1997. Half of these fail for the same combination of pollutants in both years. Vehicles that never pass the Im240 are still being driven in the I/M area; these vehicles are from all model years.
Date: April 21, 1999
Creator: Wenzel, Tom
Object Type: Article
System: The UNT Digital Library
Fresh Produce: Potential Consequences of Country-of-Origin Labeling (open access)

Fresh Produce: Potential Consequences of Country-of-Origin Labeling

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO provided information on the: (1) potential costs associated with the compliance and enforcement of a mandatory country-of-origin labeling requirement at the retail level for fresh produce; (2) potential trade issues associated with such a requirement; (3) potential impact of such a requirement on the ability of the federal government and the public to respond to outbreaks of illness caused by contaminated fresh produce; and (4) consumers' views of country-of-origin labeling."
Date: April 21, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Hybrid Blends of Non-Traditional Safety and Reliability Analysis Tools (open access)

Hybrid Blends of Non-Traditional Safety and Reliability Analysis Tools

Traditional safety and reliability analysis methods are applicable to many standard problems, including those examples illustrated in most formal courses. However, there are many real-world situations for which non-traditional methods appear to be more appropriate, mainly because most practical problems involve substantial subjectivity about the inputs and models used. This paper surveys some of the most applicable approaches found in a recent research study. Each approach is developed individually and is illuminated by selecting example situations of apparent applicability. Then, the combinational blending of the approaches with each other and with traditional methodology is discussed.
Date: April 21, 1999
Creator: Cooper, J.A.
Object Type: Article
System: The UNT Digital Library
Immigration Benefits: Applications for Adjustment of Status Under the Haitian Refugee Immigration Fairness Act of 1998 (open access)

Immigration Benefits: Applications for Adjustment of Status Under the Haitian Refugee Immigration Fairness Act of 1998

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO provided information on the number of Haitian nationals who have applied and been approved for adjustment of their status to legal permanent residence."
Date: April 21, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Interannual/decadal variability in MJO activity as diagnosed in the 40-year NCEP/NCAR reanalysis and simulated in an ensemble of GISST integrations (open access)

Interannual/decadal variability in MJO activity as diagnosed in the 40-year NCEP/NCAR reanalysis and simulated in an ensemble of GISST integrations

The Madden-Julian Oscillation (MJO) is the dominant mode of tropical variability at intraseasonal timescales. It displays substantial interannual variability in intensity which may have important implications for the predictability of the coupled system. The reasons for this interannual variability are not understood. The interannual behaviour of the MJO has been diagnosed initially in the 40-year NCEP/NCAR Reanalysis by calculating the variance of the 20-100 day filtered zonal mean zonal wind (10 o N-10 o S averaged) in a 100- day moving window. The results suggest that prior to the mid-1970s the activity of the MJO was consistently lower than during the latter part of the record. This may be related to either inadequacies in the data coverage, particularly over the tropical Indian Ocean prior to the introduction of satellite observations, or to the real effects of a decadal timescale warming in the tropical SSTs. This interdecadal trend is captured by the dominant EOF (explaining 28% of the variance) of the monthly mean SSTs (after removal of the mean seasonal cycle), as used in the NCEP/NCAR Reanalysis for the region of the tropics where the MJO is convectively active (i.e., 60 o E-180 o E, 20 o S-20 o N). During …
Date: April 21, 1999
Creator: Nortley, F; Rowell, D P; Slingo, J M & Sperber, K R
Object Type: Article
System: The UNT Digital Library
Investigation of using a Porous Media Approximation for Flow and Heat Transfer through the Nuclear Materials Storage Facility Drywell Array (open access)

Investigation of using a Porous Media Approximation for Flow and Heat Transfer through the Nuclear Materials Storage Facility Drywell Array

The Nuclear Materials Storage Facility (NMSF) is being renovated to provide a safe and secure long-term facility at Los Alamos National Laboratory to store nuclear materials. The concept for storage uses vertical tubes that are called drywells that have nuclear bearing canisters inside the tubes. The NMSF facility may use up to 370 of these tubes containing up to 10 canisters producing 15 W each. Analysts at the Laboratory wish to use CFD computer codes to predict the flow and thermal effects of air flow through the facility and the tube array. However, the complexity and large number of storage tubes precludes modeling the facility in enough detail to resolve the boundary layers around each and every tube. Therefore, certain approximations have to be made. A major approximation that has been used in this modeling effort has been to simulate the array of tubes as a porous media, The assumption-in the use of porous media is that the resistance of the drywells can be accounted for in a general way. The purpose of this study is to evaluate the suitability of the porous media approximation for modeling the tube array in the NMSF. In this study we will compare porous …
Date: April 21, 1999
Creator: Bernardin, J. D.; Gregory, W. S. & Owen, A. C.
Object Type: Article
System: The UNT Digital Library
Issues Associated with the Conveyance and Transfer of DOE Lands under Public Law 105-119 (open access)

Issues Associated with the Conveyance and Transfer of DOE Lands under Public Law 105-119

Public Law 105-119 (Law) was enacted in November 1997 as part of the Defense Authorization Act of 1998 (Act). The Law specifically requires the US Department of Energy (DOE) to identify lands that are suitable for conveyance or transfer at Los Alamos National Laboratory (LANL) within 90 days after enactment of the Act. In general, suitable lands include those parcels that are not required to meet the national security missions assigned to DOE at LANL within a ten year period beginning on the date of enactment of the Act. Additional suitability criteria are addressed below and include the need to establish clear title to the land and to restore areas contaminated with hazardous wastes. This proposed change in future land ownership is intended to serve as the final settlement of DOE community assistance obligations with respect to LANL and Los Alamos County and to stimulate economic development.
Date: April 21, 1999
Creator: Ladino, A.G.
Object Type: Article
System: The UNT Digital Library
Kosovo: International Reactions to NATO Air Strikes (open access)

Kosovo: International Reactions to NATO Air Strikes

None
Date: April 21, 1999
Creator: Donfried, Karen
Object Type: Report
System: The UNT Digital Library
Liquid waste certification plan 340 waste handling facility (open access)

Liquid waste certification plan 340 waste handling facility

This document addresses the discharges from the 340 Facility to the 300 Area Process Sewer and Retention Process Sewer.
Date: April 21, 1999
Creator: HALGREN, D.L.
Object Type: Report
System: The UNT Digital Library
Maleimide Functionalized Siloxane Resins (open access)

Maleimide Functionalized Siloxane Resins

In-situ filling through hydrolysis and condensation of silicon alkoxides has been utilized to generate nanocomposites in which the filler phase can be intimately associated with the polymer on relatively small length scales. One problem of the method has been achieving useful fill volumes without bulk phase separation of the reacting silicon monomer from the polymer. In this paper, we describe the preparation of a new class of nanocomposite materials in which the inorganic filler phase is pre-assembled before copolymerization with an organic species. Maleimide monomers, prepared from alkoxysilylpropyl amines and maleic anhydride, were protected against side reactions by forming the oxonorbornene Diels-Alder adduct with furan. The monomers were then reacted under sol-gel conditions to form oligomers or polymers-the filler phase. The material was activated by thermal deprotection of the maleimide and reacted with organic monomers or polymers to form the filled nanocomposite.
Date: April 21, 1999
Creator: Shaltout, R.M.; Loy, D.A. & Wheeler, D.R.
Object Type: Article
System: The UNT Digital Library
The mean evolution and variability of the Asian summer monsoon: comparison of ECMWF and NCEP/NCAR reanalyses (open access)

The mean evolution and variability of the Asian summer monsoon: comparison of ECMWF and NCEP/NCAR reanalyses

The behavior of the Asian Summer Monsoon is compared using the European Centre for Medium Range Weather Forecasts Reanalysis (ERA) and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis (Kalnay et al. 1996). The goals of this paper are to identify common features between the reanalyses, to assess their robustness for model validation, and especially to use reanalyses to develop their understanding of the mean evolution of the Asian Summer Monsoon and the characteristics of its interannual and intraseasonal variability (Annamalai et al. 1999).
Date: April 21, 1999
Creator: Annamalai, H.; Hodges, K.; Slingo, J. M. & Sperber, K. R.
Object Type: Article
System: The UNT Digital Library
New developments in the application of synchrotron radiation to material science. (open access)

New developments in the application of synchrotron radiation to material science.

Recent developments in the application of synchrotrons radiation to materials science are discussed, using techniques which exploit the high brilliance of the newer synchrotrons sources, such as microbeam techniques and correlation spectroscopy. These include studies of environmental systems, residual stress, slow dynamics of condensed matter systems and studies of liquid surfaces and thin magnetic films.
Date: April 21, 1999
Creator: Sinha, S. K.
Object Type: Article
System: The UNT Digital Library
Regulatory Reform: Comments on S. 746--The Regulatory Improvement Act of 1999 (open access)

Regulatory Reform: Comments on S. 746--The Regulatory Improvement Act of 1999

A statement of record issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed S.746, the Regulatory Improvement Act of 1999, focusing on: (1) the effectiveness of previous regulatory reform initiatives; (2) agencies' cost-benefit analysis practices and the trigger for the analytical requirements; (3) peer review of agencies' regulatory analyses; and (4) the transparency of the regulatory development and review process."
Date: April 21, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
The relationship between intraseasonal and interannual variability during the asian summer monsoon (open access)

The relationship between intraseasonal and interannual variability during the asian summer monsoon

The purpose of this paper is to investigate intraseasonal (30-70 days) and higher frequency (5-30 days) variability and its relationship to interannual variability. Various modelling studies have suggested a link between intraseasonal and interannual variability of the Asian summer monsoon. This relationship has been mainly based upon the similar spatial structures of the dominant EOF patterns of the monsoon circulation on intraseasonal and interannual time scales from simulations with simple models and atmospheric general circulation models. Here we investigate these relationships using 40 years of NCEP/NCAR Reanalysis. Motivation for this study is embodied in the suggestions of Charney and Shukla (1981) that boundary forcing (e.g., sea surface temperature) may predispose the monsoon system towards a dry or wet state, and the result of Palmer (1994), using the Lorenz (1963) model, that the probability of being in one regime of phase space or another is no longer equally probable in the presence of external forcing. To investigate the influence of the boundary forcing, the probability distribution functions (PDF�s) of the principal components are given.
Date: April 21, 1999
Creator: Annamalai, H; Slingo, J M & Sperber, K R
Object Type: Article
System: The UNT Digital Library