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The following ceramics were prepared for this study: the baseline ceramic, the baseline ceramic plus process impurities, a zirconolite-rich composition, a brannerite-rich composition, a composition designed to have {approx} 10% perovskite in addition to the normal baseline phases, and an {approx} 10% phosphate-doped batch. These samples were prepared by oxide (via wet or dry milling) and alkoxide-routes. The milling method has a direct effect on the samples. Incomplete milling leads to inhomogeneity in the microstructure. The main effect of incomplete milling is that unreacted actinide oxides remain in the microstructure, usually surrounded by brannerite. The phase composition also alters due to the actinide being tied up in the unreacted oxide, e.g., the pyrochlore has less actinide and additional phases, such as zirconolite may form. The approach to equilibrium is determined by a number of factors--the efficiency of the milling, the sintering time, the sintering temperature and the batch composition. The latter is very important, e.g., the zirconolite-rich batch has a slower approach to equilibrium than the baseline ceramic requiring higher sintering temperatures or longer sintering times. The addition of process impurities dramatically alters the approach to equilibrium. The additives produce a silicate liquid phase (at the sintering temperatures), which aids …

It is well known that the work function of metals decreases when they are placed in a nonpolar liquid. A similar decrease occurs when the metal is placed into contact with a semiconductor forming a Schottky barrier. We report on a new method for detecting photons using the stress caused by photo-electrons emitted from a metal film surface in contact with a semiconductor microstructure. The photoelectrons diffuse into the microstructure and produce an electronic stress. The photon detection results from the measurement of the photo-induced bending of the microstructure. Internal photoemission has been used in the past to detect photons, however, in those cases the detection was accomplished by measuring the current due to photoelectrons and not due to electronic stress. Small changes in position (displacement) of microstructures are routinely measured in atomic force microscopy (AFM) where atomic imaging of surfaces relies on the measurement of small changes (< l0{sup -9} m) in the bending of microcantilevers. In the present work we studied the photon response of Si microcantilevers coated with a thin film of Pt. The Si microcantilevers were 500 nm thick and had a 30 nm layer of Pt. Photons with sufficient energies produce electrons from the platinum-silicon …

Recently there has been an increasing demand to perform real-time in-situ chemical detection of hazardous materials, contraband chemicals, and explosive chemicals. Currently, real-time chemical detection requires rather large analytical instrumentation that are expensive and complicated to use. The advent of inexpensive mass produced MEMS (micro-electromechanical systems) devices opened-up new possibilities for chemical detection. For example, microcantilevers were found to respond to chemical stimuli by undergoing changes in their bending and resonance frequency even when a small number of molecules adsorb on their surface. In our present studies, we extended this concept by studying changes in both the adsorption-induced stress and photo-induced stress as target chemicals adsorb on the surface of microcantilevers. For example, microcantilevers that have adsorbed molecules will undergo photo-induced bending that depends on the number of absorbed molecules on the surface. However, microcantilevers that have undergone photo-induced bending will adsorb molecules on their surfaces in a distinctly different way. Depending on the photon wavelength and microcantilever material, the microcantilever can be made to bend by expanding or contracting the irradiated surface. This is important in cases where the photo-induced stresses can be used to counter any adsorption-induced stresses and increase the dynamic range. Coating the surface of the …

The local strain and texture in Al interconnect wires have been investigated using white and monochromatic x-ray microbeams on the MHATTCAT undulator beam line at the Advanced Photon Source. Intergrain and intragrain orientations were obtained with ~0.01 degree sensitivity using white beam measurements on wide Al pads (~100 Mu-m) and thin (2 Mu-m) Al wires. Orientation changes of up to 1 degree were found within individual grains of the (111) textured Al interconnects. Deviatoric strain measurements indicate small intragranular strain variations, but intergranular strain variations were found to be quite large.

Tank 241-SY-101 waste level growth is an emergent, high priority issue. The purpose of this document is to record the hazards evaluation process and document potential hazardous conditions that could lead to the release of radiological and toxicological material from the proposed transfer of a limited quantity (approximately 100,000 gallons) of waste from Tank 241-SY-101 to Tank 241-SY-102. The results of the hazards evaluation were compared to the current Tank Waste Remediation System (TWRS) Basis for Interim Operation (HNF-SD-WM-BIO-001, 1998, Revision 1) to identify any hazardous conditions where Authorization Basis (AB) controls may not be sufficient or may not exist. Comparison to LA-UR-92-3196, A Safety Assessment for Proposed Pump Mixing Operations to Mitigate Episodic Gas Releases in Tank 241-SY-101, was also made in the case of transfer pump removal activities. Revision 1 of this document deletes hazardous conditions no longer applicable to the current waste transfer design and incorporates hazardous conditions related to the use of an above ground pump pit and overground transfer line. This document is not part of the AB and is not a vehicle for requesting authorization of the activity; it is only intended to provide information about the hazardous conditions associated with this activity. The …

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Thin film CoPt/Co bilayers have been prepared as a model system to investigate the relationship between microstructure and exchange coupling in two-phase hard/soft composite magnets. CoPt films, with a thickness of 25 nm, were sputter-deposited from a nearly equiatomic alloy target onto oxidized Si wafers. The films were subsequently annealed at 700 C and fully transformed from the FCC phase to the magnetically hard, ordered L1{sub 0} phase. The coercivity of the films increased rapidly with annealing time until it reached a plateau at approximately 9.5 kOe. Fully-ordered CoPt films were then used as substrates for deposition of Co layers, with thicknesses in the range of 2.8--225 nm, in order to produce the hard/soft composite bilayers. As predicted by theory, the magnetic coherency between the soft Co phase and the hard, ordered CoPt phase decreased as the thickness of the soft phase increased. This decrease in coupling was clearly seen in the magnetic hysteresis loops of the bilayers. At small thicknesses of Co (a few nanometers), the shape of the loop was one of a uniform material showing no indication of the presence of two phases with extremely different coercivities. At larger Co thicknesses, constricted loops, i.e., ones showing the …

Surface pressure data from the National Renewable Energy Laboratory's ''Unsteady Aerodynamics Experiment'' were analyzed to characterize the impact of three-dimensionality, unsteadiness, and flow separation effects observed to occur on downwind horizontal axis wind turbines (HAWT). Surface pressure and strain gage data were collected from two rectangular planform blades with S809 airfoil cross-sections, one flat and one twisted. Both blades were characterized by the maximum leading edge suction pressure and by the azimuth, velocity, and yaw at which it occurred. The occurrence of dynamic stall at all but the inboard station (30% span) shows good quantitative agreement with the theoretical limits on inflow velocity and yaw that should yield dynamic stall events. A full three-dimensional characterization of the surface pressure topographies combined with flow visualization data from surface mounted tufts offer key insights into the three-dimensional processes involved in the unsteady separation process and may help to explain the discrepancies observed with force measurements at 30% span. The results suggest that quasi-static separation and dynamic stall analysis methods relying on purely two-dimensional flow characterizations may not be capable of simulating the complex three-dimensional flows observed with these data.

Melt-quenched NdFeB is an important modern permanent magnet material. However there still remains doubt as to the magnetization reversal mechanism which controls coercivity in material prepared by this processing route. To investigate this problem a new technique based on measurements of reversible magnetization along recoil curves has been used. The technique identifies the presence of free domain walls during magnetic reversal. For this study samples of isotropic (MQI), hot pressed (MQII) and die upset (MQIII) melt-quenched NdFeB were examined. The results indicate that in MQI free domain walls are not present during reversal and the reversal mechanism is most likely incoherent rotation of some form. Free domain walls are also not present during reversal in the majority of grains of MQII, even though initial magnetization measurements indicate that the grain size is large enough to support them. In MQIII free domain walls are present during reversal. These results are attributed to the reduced domain wall nucleation field in MQIII compared with MQII and the increased dipolar interactions in MQIII.

The growth and properties of undoped and Mn-doped ZnGa{sub 2}O{sub 4} thin-film phosphors on (100) MgO and glass substrates using pulsed laser ablation were investigated. Blue-white and green emission were observed for as-deposited undoped and Mn-doped films, respectively. Luminescent properties as well as crystallinity were considerably affected by processing conditions and film stoichiometry. Films with enhanced luminescent characteristics were obtained on single crystal substrates without post-annealing.

This survey collected information from state government and city government fleet drivers who operate light-duty alternative fuel vehicles(AFVs). The survey posed questions about AFV use, fuel use and availability and performance.

Melt-quenched NdFeB is an important modern permanent magnet material. However, there still remains doubt as to the magnetization reversal mechanism which controls coercivity in material prepared by this processing route. To investigate this problem a new technique based on measurements of reversible magnetization along recoil curves has been used. The technique identifies the presence of free domain walls during magnetic reversal. For this study samples of isotropic (MQI), hot pressed (MQII) and die upset (MQIII) melt-quenched NdFeB were examined. The results indicate that in MQI free domain walls are not present during reversal and the reversal mechanism is most likely incoherent rotation of some form. Free domain walls are also not present during reversal in the majority of grains of MQII, even though initial magnetization measurements indicate that the grain size is large enough to support them. In MQIII free domain walls are present during reversal. These results are attributed to the reduced domain wall nucleation field in MQIII compared with MQII and the increased dipolar interactions in MQIII.

This eleventh quarterly report describes work done during the eleventh three-month period of the University of Pittsburgh's project on the ``Treatment of Metal-Laden Hazardous Wastes with Advanced Clean Coal Technology By-Products.'' This report describes the activities of the project team during the reporting period. The principal work has focused upon new laboratory evaluation of samples from Phase 1, discussions with MAX Environmental Technologies, Inc., on the field work of Phase 2, preparing and giving presentations, and making and responding to two outside contacts.

We have developed a novel chemical detection technique based on infrared micro-calorimetric spectroscopy that can be used to identify the presence of trace amounts of very low vapor pressure target compounds. Unlike numerous recently developed low-cost sensor approaches, the selectivity is derived from the unique differential temperature spectrum and does not require the questionable reliability of highly selective coatings to achieve the required specificity. This is accomplished by obtaining the infrared micro-calorimetric absorption spectrum of a small number of molecules absorbed on the surface of a thermal detector after illumination through a scanning monochromator. We have obtained infrared micro-calorimetric spectra for explosives such as TNT over the wavelength region 2.5 to 14.5 Mu-m. Thus both sophisticated and relatively crude explosive compounds and components are detectable with these ultra-sensitive thermal-mechanical micro-structures. In addition to the above mentioned spectroscopy technique and associated data, the development of these advanced thermal detectors is also presented in detail.

We have applied Atomic Number Contract Scanning Transmission Electron Microscopy (Z-Contrast STEM) and STEM/EELS (Electron Energy Loss Spectroscopy) towards the study of colloidal CdSe semiconductor nanocrystals embedded in MEH-PPV polymer films. Unlike the case of conventional phase-contrast High Resolution TEM, Z-Contrast images are direct projections of the atomic structure. Hence they can be interpreted without the need for sophisticated image simulation and the image intensity is a direct measure of the thickness of a nanocrystal. Our thickness measurements are in agreement with the predicted faceted shape of these nanocrystals. Our unique 1.3A resolution STEM has successfully resolve3d the sublattice structure of these CdSe nanocrystals. In [010] projection (the polar axis in the image plane) we can distinguish Se atom columns from Cd columns. Consequently we can study the effects of lattice polarity on the nanocrystal morphology. Furthermore, since the STEM technique does not rely on diffraction, it is superbly suited to the study of non-periodic detail, such as the surface structure of the nanocrystals. EELS measurements on individual nanocrystals indicate a significant amount (equivalet to 0.5-1 surface monolayers) of oxygen on the nanocrystals, despite processing in an inert atmosphere. Spatially resolved measurements at 7A resolution suggest a surface oxide layer. …

The authors present a detection process capable of directly imaging the transverse amplitude, phase, and Doppler shift of coherent electromagnetic fields. Based on coherent detection principles governing conventional heterodyned RADAR/LADAR systems, Fourier Transform Heterodyne incorporates transverse spatial encoding of the reference local oscillator for image capture. Appropriate selection of spatial encoding functions allows image retrieval by way of classic Fourier manipulations. Of practical interest: (1) imaging may be accomplished with a single element detector/sensor requiring no additional scanning or moving components, (2) as detection is governed by heterodyne principles, near quantum limited performance is achievable, (3) a wide variety of appropriate spatial encoding functions exist that may be adaptively configured in real-time for applications requiring optimal detection, and (4) the concept is general with the applicable electromagnetic spectrum encompassing the RF through optical.

The authors present a preliminary analysis and design framework developed for the evaluation and optimization of infrared, Imaging Spatial Heterodyne Spectrometer (SHS) electro-optic systems. Commensurate with conventional interferometric spectrometers, SHS modeling requires an integrated analysis environment for rigorous evaluation of system error propagation due to detection process, detection noise, system motion, retrieval algorithm and calibration algorithm. The analysis tools provide for optimization of critical system parameters and components including : (1) optical aperture, f-number, and spectral transmission, (2) SHS interferometer grating and Littrow parameters, and (3) image plane requirements as well as cold shield, optical filtering, and focal-plane dimensions, pixel dimensions and quantum efficiency, (4) SHS spatial and temporal sampling parameters, and (5) retrieval and calibration algorithm issues.

We have discussed two aspects of creating high integrity software that greatly benefit from the availability of transformation technology, which in this case is manifest by the requirement for a sophisticated backtracking parser. First, because of the potential for correctly manipulating programs via small changes, an automated non-procedural transformation system can be a valuable tool for constructing high assurance software. Second, modeling the processing of translating data into information as a, perhaps, context-dependent grammar leads to an efficient, compact implementation. From a practical perspective, the transformation process should begin in the domain language in which a problem is initially expressed. Thus in order for a transformation system to be practical it must be flexible with respect to domain-specific languages. We have argued that transformation applied to specification results in a highly reliable system. We also attempted to briefly demonstrate that transformation technology applied to the runtime environment will result in a safe and secure system. We thus believe that the sophisticated multi-lookahead backtracking parsing technology is central to the task of being in a position to demonstrate the existence of HIS.

Mission critical applications of MEMS devices require knowledge of the distribution in their material properties and long-term reliability of the small-scale structures. This project reports on a new testing program at Sandia to quantify the strength distribution using samples that reflect the dimensions of critical MEMS components. The strength of polysilicon fabricated with Sandia's SUMMiT 4-layer process was successfully measured using samples with gage sections 2.5 {micro}m thick by 1.7 {micro}m wide and lengths of 15 and 25 {micro}m. These tensile specimens have a freely moving pivot on one end that anchors the sample to the silicon die and prevents off axis loading during testing. Each sample is loaded in uniaxial tension by pulling laterally with a flat tipped diamond in a computer-controlled Nanoindenter. The stress-strain curve is calculated using the specimen cross section and gage length dimensions verified by measuring against a standard in the SEM. The first 48 samples had a means strength of 2.24 {+-} 0.35 GPa. Fracture strength measurements grouped into three strength levels, which matched three failure modes observed in post mortem examinations. The seven samples in the highest strength group failed in the gage section (strength of 2.77 {+-} 0.04 GPa), the moderate strength …

Scenario development has two primary purposes in the design and documentation of post-closure performance assessments in a regulatory setting. First, scenario development ensures a sufficiently comprehensive consideration of the possible future states of the system. Second, scenario development identifies the important scenarios that must be considered in quantitative analyses of the total system performance assessment (TSPA). Section 2.0 of this report describes the scenario development process. Steps in the process are described in Section 2.1, and terms introduced in this section are defined in Section 2.2. The electronic database used to document the process is described in Section 3, and Section 4 provides a summary of the current status of the YMP scenario development work. Section 5 contains acknowledgments, and Section 6 contains a list of the references cited.

We present experimented results directed at understanding the growth and structure of metallic barrier layer and interconnect films. Numerical simulation results associated with this experimental work are presented in an accompanying paper in these proceedings. Here, thin films of Al, Ti, Cu and Ta have been grown by magnetron sputtering onto oxidized Si substrates. Using a specially-constructed substrate holder, the orientation of the substrate with respect to the growth direction was varied from horizontal to vertical. Films were grown at both low and high argon pressure; in the case of Ta, the cathode power was varied as well. The film structure and in particular the surface roughness was measured by X-ray reflectance and also by atomic force microscopy. We find that the surface roughness increases markedly with orientation angle in the case of Ta and Cu films, and in Ti films grown at high argon pressure. At low pressure, however, the Ti film surface roughness remains constant for all substrate orientations. No variation in roughness with either orientation angle or argon pressure was observed in the Al films. These results suggest that, under certain circumstances, shadowing effects and/or grain orientation (i.e., texture) competition during growth can give rise to lower …

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In order to develop an alternative buffer layer architecture using the sol-gel process to produce YBCO (YBa2Cu307+) coated conductors, Yb203 has been chosen as the candidate material. Buffer layers of fi03 were epitaxkdly grown on biaxially textured-Ni (100) substrates by the sol gel process for the first time. The ~03 precursor solution was prepared from an alkoxide sol-gel route in 2-xnetho~ethanol and was deposited on textured-Ni (100) substrates by either spin coating or dip coating methods. The amorphous film was then processed at 1160oC under flowing (96%)MH2(4%) gas mixture for one hour. The fi03 iihn exhibited a strong c-axis orientation on the Ni (100) substrates. The phi and omega scans indicated good in plane and out of plane orientations. The X-ray (222) pde figure showed a cube-on-cube epitaxy. High current YBCO films were grown on the Y&03 sol-gel buffered-Ni substrates.