Unidirectional fibrous monoliths (FMs) based on dense, strong ZrSiO{sub 4} cells that were surrounded by a porous, weaker ZrSiO{sub 4} cell-boundary phase were fabricated. A duplex filament was coextruded, sectioned, bundled, and the resulting bundle was extruded to form a new filament. This filament was cut and packed into plate and bar dies to produce FM test specimens. Four-point flexural tests were conducted on the cell material, cell-boundary material, and FMs. After testing, fracture surfaces and cross sections were examined by scanning electron microscopy. The FMs exhibited graceful failure in flexural testing, and the fracture surfaces exhibited clear evidence of crack deflection and delamination.

This document describes a fatigue lifetime acceptance test criterion by which studs having rolled threads, larger than 1.0 inches (25 mm) in diameter, can be assured to meet minimum quality attributes associated with a controlled rolling process.

A defining property of metals is the existence of a Fermi surface: for two dimensions, a continuous contour in momentum space which separates occupied from unoccupied states. In this paper, I discuss angle resolved photoemission data on the cuprate superconductor BSCCO and argue that it is not best thought of in this conventional picture. Rather, the data are consistent with patches of finite area connected by more conventional arcs. Novel physics is associated with the patches, in that the states contained in a patch are dispersionless and thus interaction dominated. In the pseudogap phase, the patches are gapped out, leaving the Fermi arcs disconnected. This unusual situation may be the key to understanding the microscopic physics of the high temperature superconductors, in that the pairing correlations are strongest in the patches, yet the superfluid density lives only on the arcs.

There is a new magnetic alloy called Finemet which has very constant {mu}'{sub p}Qf up to {approximately} 2 kG and is very stable at high magnet flux density and temperature. It may be a good can-didate for high-gradient rf cavities. However, it has a rather low quality factor and is therefore very lossy. We compare the pros and cons of Finemet versus the common ferrite, when used in low-energy accelerating cavities, insertion for space-charge compensation, and barrier cavities.

The electrometallurgical treatment of metallic spent nuclear fuel produces two high-level waste streams; cladding hulls and chloride salt. Argonne National Laboratory is developing a glass bonded sodalite waste form to immobilize the salt waste stream. The waste form consists of 75 Vol.% crystalline sodalite (containing the salt) with 25 Vol.% of an ''intergranular'' glassy phase. Microindentation fracture toughness measurements were performed on representative samples of this material using a Vickers indenter. Palmqvist cracking was confirmed by post-indentation polishing of a test sample. Young's modulus was measured by an acoustic technique. Fracture toughness, microhardness, and Young's modulus values are reported, along with results from scanning electron microscopy studies.

A better understanding of the fraction of contaminants irreversibly sorbed by minerals is necessary to effectively quantify bioavailability. Ferrihydrite, a poorly crystalline iron oxide, is a natural sink for sorbed contaminants. Contaminants may be sorbed/occluded as ferrihydrite precipitates in natural waters or as it ages and transforms to more crystalline iron oxides such as goethite or hematite. Laboratory studies indicate that Cd, Co, Cr, Cu, Ni, Np, Pb, Sr, U, and Zn are irreversibly sorbed to some extent during the aging and transformation of synthetic ferrihydrite. Barium, Ra and Sr are known to sorb on ferrihydrite in the pH range of 6 to 10 and sorb more strongly at pH values above its zero point of charge (pH> 8). We will review recent literature on metal retardation, including our laboratory and modeling investigation of Ba (as an analogue for Ra) and Sr adsorption/resorption, during ferrihydrite transformation to more crystalline iron oxides. Four ferrihydrite suspensions were aged at pH 12 and 50 °C with or without Ba in 0.01 M KN03 for 68 h or in 0.17 M KN03 for 3424 h. Two ferrihydrite suspensions were aged with and without Sr at pH 8 in 0.1 M KN03 at 70°C. Barium …

This program seeks to better define electrode-electrolyte interfaces and solid-state ion transport mechanisms that are a central feature of fuel cells and advanced electrochemical systems. The goal is to develop a new generation of materials with enhanced energy efficiency and reduced tendency toward dendrite or passive film formation at the electrode-electrolyte interface.

Sandia National Laboratories has undertaken an ambitious, multiyear effort to greatly improve our parachute system modeling and analysis capabilities. The impetus for this effort is twofold. First, extending the stockpile lifetime raises serious questions regarding the ability of the parachutes to meet their requirements in the future due to material aging. These aging questions cannot currently be answered using available tools and techniques which are based upon the experience of expert staff and full-scale flight tests and are, therefore, not predictive. Second, the atrophy of our parachute technology base and the loss of our experienced staff has eroded our ability to respond to any future problems with stockpiled parachutes or to rapidly design a new parachute system on an experience base alone. To assure a future in-house capability for technical oversight of stockpile nuclear weapon parachutes, Sandia must move from our present empirically based approach to a computationally based, predictive methodology. This paper discusses the current status of the code development and experimental validation activities. Significant milestones that have been achieved and those that are coming up in the next year are discussed.

Argonne National Laboratory is developing a ceramic waste form to immobilize salt containing fission products and transuranic elements. Preliminary results have been presented for ceramic waste forms containing surrogate fission products such as cesium and the lanthanides. In this work results from scanning electron microscopy/energy dispersive spectroscopy and x-ray diffraction are presented in greater detail for ceramic waste forms containing surrogate fission products. Additionally, results for waste forms containing plutonium and surrogate fission products are presented. Most of the surrogate fission products appear to be silicates or aluminosilicates whereas the plutonium is usually found in an oxide form. There is also evidence for the presence of plutonium within the sodalite phase although the chemical speciation of the plutonium is not known.

Ferrochelatase (EC 4.99.1.1), the terminal enzyme of the heme biosynthetic pathway, catalyzes Fe²⁺ chelation into protoporphyrin IX. Resonance Raman and W-visible absorbance spectroscopes of wild type and engineered variants of murine ferrochelatase were used to examine the proposed structural mechanism for iron insertion into protoporphyrin by ferrochelatase. The recombinant variants (i.e., H207N and E287Q) are enzymes in which the conserved amino acids histidine-207 and glutamate-287 of murine ferrochelatase were substituted with asparagine and glutamine, respectively. Both of these residues are at the active site of the enzyme as deduced from the Bacillus subtilis ferrochelatase three-dimensional structure. Addition of free base or metalated porphyrins to wild type ferrochelatase and H207N variant yields a quasi 1:1 complex, possibly a monomeric protein-bound species. In contrast, the addition of porphyrin (either free base or metalated) to E287Q is sub-stoichiometric, as this variant retains bound porphyrin in the active site during isolation and purification. The specificity of porphyrin binding is confirmed by the narrowing of the structure-sensitive resonance Raman lines and the vinyl vibrational mode. Resonance Raman spectra of free base and metalated porphyrins bound to the wild type ferrochelatase indicate a nonplanar distortion of the porphyrin macrocycle, although the magnitude of the distortion cannot …

Microstructural-level residual stresses arise in ceramics due to thermal expansion anisotropy. The magnitude of these stresses can be very high and may cause spontaneous microcracking during the processing of these materials. The orientation data obtained by backscattered electron diffraction and grain boundary energies obtained by AFM were used in conjunction with an object oriented finite element analysis package (OOF) to predict the magnitude of residual stresses in alumina. Crack initiation and propagation were also simulated based on the Griffith fracture criterion.

A novel bioprocessing technology was developed that efficiently converts negative-value organic waste, including domestic refuse, animal manures, industrial wastes, food processing wastes, and municipal sewage sludge into saleable products, including fuel gas and compost. This technology is known as high solids anaerobic digestion and was developed at NREL from fundamental research to laboratory- and intermediate-scale system evaluations.

Waste stored in Hdord single-shell Tank 241-C-106 will be sluiced with a supernatant liquid from doubIe-shell Tank 241 -AY- 102 (AY-1 02) at the U.S. Department of Energy's Har@ord Site in Eastern Washington. The resulting slurry, containing up to 30 wtYo solids, will then be transferred to Tank AY-102. During the sluicing process, it is important to know the mass of the solids being transferred into AY- 102. One of the primary instruments used to measure solids transfer is an E+ densitometer located near the periphery of the tank at riser 15S. This study was undert.dcen to assess how well a densitometer measurement could represent the total mass of soiids transferred if a uniform lateral distribution was assumed. The study evaluated the C-1 06 slurry mixing and accumulation in Tank AY- 102 for the following five cases: Case 1: 3 wt'%0 slurry in 6.4-m AY-102 waste Case 2: 3 w-t% slurry in 4.3-m AY-102 waste Case 3: 30 wtYo slurry in 6.4-m AY-102 waste Case 4: 30 wt% slurry in 4.3-m AY-102 waste Case 5: 30 wt% slurry in 5. O-m AY-102 waste. The tirne-dependent, three-dimensional, TEMPEST computer code was used to simulate solid deposition and accumulation during the injection …

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The first synthesis of an octahalotetraalkylporphyrin [2,3,7,8,12,13,17,18 -octabromo-5,10,15,20- tetrakis(trifluoromethyl)porphinato nickel(II)] is reported; this perhalogenated porphyrin has several novel properties including a very nonplanar ruffled structure with an unusually short Ni- N distance, an extremely red-shifted optical spectrum, and hindered rotation of the trifluoromethyl groups ({Delta}G_278K =47 kJ mol^-1).

Studies directed at understanding structural and electronic properties of silver clusters have been and remain the subject of an active theoretical [1-22] and experimental [23- 38] effort. One of the reasons is the (still) important role these systems play in the photographic process. Investigations of interactions of silver clusters with different atoms and molecules are motivated primarily by a possible utility of these clusters in catalytic processes. The important role of silver in the selective oxidation of ethylene into ethylene oxide, the feedstock for polyester production, is well-known [39]. Possible variations in chemical reactivity with the cluster size and understanding of the mechanisms of interactions with different ligands may lead to new and more efficient applications. Investigations of cluster-ligand systems also contribute a great deal to a better understanding of gas-surface interactions. Accordingly, theoretical studies of silver clusters and cluster-ligand systems [40-44] fall into two categories--those that use clusters as models for silver surfaces [40], and those that target clusters and cluster-ligand interactions as subjects in their own right [41-44]. The common goal of all these studies is to elucidate the nature of the interatomic interactions and bonding at the microscopic level and thereby arrive at a fundamental understanding and …

Thermal management is a cross-cutting technology that directly or indirectly affects engine performance, fuel economy, safety and reliability, aerodynamics, driver/passenger comfort, materials selection, emissions, maintenance, and component life. This review paper provides an assessment of thermal management for large trucks, particularly as it impacts these features. Observations arrived at from a review of the state of the art for thermal management for over-the-road trucks are highlighted and commented on. Trends in the large truck industry, pertinent engine truck design and performance objectives, and the implications of these relative to thermal management, are presented. Finally, new thermal management concepts for high efficiency vehicles are described.

The field of synchrotron radiation research has grown rapidly over the last 25 years due to both the push of the accelerator and magnet technology that produces the x-ray beams and the pull of the extraordinary scientific research that is possible with them. Three successive generations of synchrotrons radiation facilities have resulted in beam brilliances 11 to 12 orders of magnitude greater than the standard laboratory x-ray tube. However, greater advances can be easily imagined given the fact that x-ray beams from present-day facilities do not exhibit the coherence or time structure so familiar with the optical laser. Theoretical work over the last ten years or so has pointed to the possibility of generating hard x-ray beams with laser-like characteristics. The concept is based on self-amplified spontaneous emission (SASE) in flee-electron lasers. A major facility of this type based upon a superconducting linac could produce a cost-effective facility that spans wave-lengths from the ultraviolet to the hard x-ray regime, simultaneously servicing large numbers experimenters from a wide range of disciplines. As with each past generation of synchrotrons facilities, immense new scientific opportunities would result from fourth-generation sources.

This sampling and analysis plan identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained to address vapor issues related to the sluicing of tank 241-C-106. Sampling will be performed in accordance with Waste Retrieval Sluicing System Emissions Collection Phase III (Jones 1999) and Process Test Plan Phase III, Waste Retrieval Sluicing System Emissions Collection (Powers 1999). Analytical requirements include those specified in Request for Ecology Concurrence on Draft Strategy/Path Forward to Address Concerns Regarding Organic Emissions from C-106 Sluicing Activities (Peterson 1998). The Waste Retrieval Sluicing System was installed to retrieve and transfer high-heat sludge from tank 241-C-106 to tank 241-AY-102, which is designed for high-heat waste storage. During initial sluicing of tank 241-C-106 in November 1998, operations were halted due to detection of unexpected high volatile organic compounds in emissions that exceeded regulatory permit limits. Several workers also reported smelling sharp odors and throat irritation. Vapor grab samples from the 296-C-006 ventilation system were taken as soon as possible after detection; the analyses indicated that volatile and semi-volatile organic compounds were present. In December 1998, a process test (phase I) was conducted in which the pumps in tanks 241-C-106 and 241-AY-102 …

Wet oxidation of high-Al-content AIGaAs semiconductor layers in vertical cavity surface emitting lasers (VCSELS) has produced devices with record low threshold currents and voltages and with wall-plug efficiencies greater than 50%. Wet oxidation of buried AlGaAs layers has been employed to reduce the problems associated with substrate current leakage in GaAs-on- insulator (GOI) MESFETS. Wet oxidation of high-Al-content AlGaAs semiconductor layers in vertical cavity surface emitting lasers (VCSELS) has produced devices with record low threshold currents and voltages and with wall-plug efficiencies greater than 50%. Wet oxidation of buried AlGaAs layers has been employed to reduce the problems associated with substrate current leakage in GaAs-on- insulator (GOI) MESFETS. Wet oxidation has also been considered as a route to the long-sought goal of a IH-V MIS technology. To continue improving device designs for even higher performance and to establish a truly manufacturable technology based on wet oxidation, the effect of oxidation of a given layer on the properties of the entire device structure must be understood. The oxidation of a given layer can strongly affect the electrical and chemical properties of adjacent layers. Many of these effects are derived from the production of large amounts of elemental As during the oxidation …

Vertical-bore, geothermal heat pumps (GHPs) have been providing heating and cooling to four new elementary schools located in Lincoln, Nebraska since 1995. According to representatives of the local utility and school district, the systems are providing a comfortable, complaint-free environment with utility costs that are nearly half of that of other schools in the district. Performance data collected from on-site energy management systems and district billing and utility records for all fifty schools in the Lincoln district indicate that only five consume less energy than the best performing GHP school; however these five cool less than 10% of their total floor area, while the GHP schools cool 100% of their floor area. When compared to other new schools (with similar ventilation loads), the GHP schools used approximately 26% less source energy per square foot of floor area. Variations in annual energy performance are evident among the four GHP schools, however, together they still consume less source energy than 70% of all schools in the district. These variations are most likely due to operational differences rather than installed equipment, building orientation, or environmental (bore field) conditions.

The Lincoln Public School District, in Lincoln, Nebraska, recently installed vertical-bore geothermal heat pump systems in four, new, elementary schools. Because the district has consistent maintenance records and procedures, it was possible to study repair, service and corrective maintenance requests for 20 schools in the district. Each school studied provides cooling to over 70% of its total floor area and uses one of the following heating and cooling systems: vertical-bore geothermal heat pumps (GHPs), air-cooled chiller with gas-fired hot water boiler (ACUGHWB), water-cooled chiller with gas-fired hot water boiler (WCCYGHWB), or water-cooled chiller with gas-fired steam boiler (WCUGSB). Preventative maintenance and capital renewal activities were not included in the available database. GHP schools reported average total costs at 2.13 cents/ft{sup 2}-yr, followed by ACC/GHWB schools at 2.88 cents/ft{sup 2}-yr, WCC/GSB schools at 3.73 cents/ft{sup 2}-yr, and WCC/GHWB schools at 6.07 cents/ft{sup 2}-yr. Because of tax-exemptions on material purchases, a reliance on in-house labor, and the absence of preventative maintenance records in the database, these costs are lower than those reported in previous studies. A strong relationship (R{sup 2}=O.52) was found between costs examined and cooling system age: the newer the cooling equipment, the less it costs to maintain.

This Corrective Action Decision Document (CADD) has been prepared for Corrective Action Unit (CAU) 423, Building 03-60 Underground Discharge Point (UDP) in accordance with the Federal Facility Agreement and Consent Order (FFACO) of 1996 that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the Nevada Division of Environmental Protection (NDEP); and the U.S Department of Defense (FFACO, 1996). The CADD provides or references the specific information necessary to recommend a preferred corrective action for the single Corrective Action Site (CAS), 03-02-002-0308, within CAU 423. Corrective Action Unit 423 is located at the Tonopah Test Range (TTR), Nevada. The TTR is approximately 255 kilometers (km) (140 miles[mi]) northwest of Las Vegas, Nevada. The UDP is approximately 73 meters (m) (240 feet [ft]) northwest of the northwest corner of Building 03-60, the Auto Maintenance Shop. Corrective Action Unit 423 is comprised of the UDP and an associated discharge line extending from Building 03-60. The UDP received waste oil products from the Auto Maintenance Shop, a light-duty fleet maintenance shop in the Area 3 compound, from 1965 to 1989 or 1990 (DOE/NV, 1997).

A new ground source heat pump routine has been incorporated in the DOE-2 building simulation program, but field validation of this routine is limited. Measured data are available for the operation of a ground source heat pump system for Maxey School, located in Lincoln, NE. Temperatures of the propylene glycol solution flowing in and out of the heat pump system vertical well field as predicted by the DOE-2 routine were compared with the measured data. The results showed a need for improvement in the routine, and a number of improvements were made. These changes helped, but some of the input parameters still had to be adjusted to obtain a reasonably good fit to the measured data. Future areas of investigation were suggested and a course of action was recommended.