Fibrous monoliths (FMs) based on mullite combined with Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} have been produced. These FMs incorporate duplex cells in which compressive residual stresses were engineered into the surfaces of the cells. The residual stresses should increase average cell strength, which may allow them to achieve mechanical properties comparable to those of Si{sub 3}N{sub 4}/BN FMs. The expected residual stresses have been calculated, and data on sintering and thermal expansion have been gathered. Prototype FMs were produced and their microstructure examined.

For those chemical elements which have no stable nuclides with a terrestrial isotopic composition, the data on radioactive half-lives and relative atomic masses for the nuclides of interest and importance have been evaluated and the recommended values and uncertainties are listed.

For those chemical elements which have no stable nuclides with a terrestrial isotopic composition, the data on radioactive half-lives and relative atomic masses for the nuclides of interest and importance have been evaluated and the recommended values and uncertainties are listed.

The science and technology of ferroelectric thin films has experienced an explosive development during the last ten years. Low-density non-volatile ferroelectric random access memories (NVFRAMS) are now incorporated in commercial products such as ''smart cards'', while high permittivity capacitors are incorporated in cellular phones. However, substantial work is still needed to develop materials integration strategies for high-density memories. We have demonstrated that the implementation of complementary in situ characterization techniques is critical to understand film growth and device processes relevant to device development. We are using uniquely integrated time of flight ion scattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry (SE) techniques to perform in situ, real-time studies of film growth processes in the high background gas pressure required to growth ferroelectric thin films. TOF-ISARS provides information on surface processes, while SE permits the investigation of buried interfaces as they are being formed. Recent studies on SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub x}Sr{sub 1{minus}x}TiO{sub 3} (BST) film growth and interface processes are discussed. Direct imaging of ferroelectric domains under applied electric fields can provide valuable information to understand domain dynamics in ferroelectric films. We discuss results of piezoresponse scanning force microscopy (SFM) imaging for nanoscale studies of polarization reversal …

The health costs associated with urban air pollution are a growing problem faced by all societies. Automobiles burning gasoline and diesel contribute a great deal to this problem. The cost to the United States of imported oil is more than US$50 billion annually. Economic alternatives are being actively sought. Hydrogen fuel, used in an internal combustion engine optimized for maximum efficiency and as part of a hybrid-electric vehicle, will give excellent performance and range (>480 km) with emissions well below the ultra-low emission vehicle standards being required in California. These vehicles can also be manufactured without excessive cost. Hydrogen-fueled engines have demonstrated indicated efficiencies of more than 50% under lean operation. Combining engine and other component efficiencies, the overall vehicle efficiency should be about 40%, compared with 13% for a conventional vehicle in the urban driving cycle. The optimized engine-generator unit is the mechanical equivalent of the fuel cell but at a cost competitive with today`s engines. The increased efficiency of hybrid-electric vehicles now makes hydrogen fuel competitive with today`s conventional vehicles. Conservative analysis of the infrastructure options to support a transition to a hydrogen-fueled light-duty fleet indicates that hydrogen may be utilized at a total cost comparable to what …

A variety of nondestructive evaluation techniques were utilized to document the damage characteristics of a Si{sub 3}N{sub 4}-BN fibrous monolith. The techniques included X-ray radiography, infrared thermography, ultrasonic C-scanning, and acoustic emission detection. The focus of this paper is the nondestructive evaluation results from a modified single-edge notched tensile specimen inspected before and after testing. Of the techniques performed, the thermography and ultrasonic methods were the most successful at identifying the predominant types of damage incurred in the fibrous monolith material. Polished cross-sections of the specimen revealed that hairline cracks had developed along inter- and intra-laminar BN cell bundle boundaries. Neither type of crack could be identified from the X-ray radiograph. The delaminated zones were matched with results from the thermography and C-scans. The acoustic emissions correlated well with changes in the load-displacement data and provided source locations consistent with the thermal and C-scan images.

High power density electronic components such as fast microprocessors and power semiconductors must operate below the maximum rated device junction temperature to ensure reliability. function temperatures are determined by the amount of heat generated and the thermal resistance from junction to the ambient thermal environment. Two of the Largest contributions to this thermal resistance are the die attach interface and the package base. A decrease in these resistances can allow increased component packing density in MCMs, reduction of heat sink volume in tightly packed systems, enable the use of higher performance circuit components, and improve reliability. The substrate for high power density devices is the primary thermal link between the junctions and the heat sink. Present high power multichip modules and single chip packages use substrate materials such as silicon nitride or copper tungsten that have thermal conductivity in the range of 200 W/mK. We have developed Dymalloy, a copper-diamond composite, that has a thermal conductivity of 420 W/mK and an adjustable coefficient of thermal expansion, nominally 5.5 ppm/C at 25 C, compatible with silicon and gallium arsenide. Because of the matched coefficient of thermal expansion it is possible to use low thermal resistance hard die attach methods. Dymalloy is …

The paper discusses current European nuclear data measurement and evaluation requirements for fission reactor technology applications and problems involved in meeting the requirements. Reference is made to the NEA High Priority Nuclear Data Request List and to the production of the new JEFF-3 library of evaluated nuclear data. There are requirements for both differential (or basic) nuclear data measurements and for different types of integral measurement critical facility measurements and isotopic sample irradiation measurements. Cross-section adjustment procedures are being used to take into account the simpler types of integral measurement, and to define accuracy needs for evaluated nuclear data.

Two-particle correlations between pions in Au+Au collisions have been measured at beam kinetic energies of 6, 8, and 10.6 GeV/u at the Alternating Gradient Synchrotron (AGS) over a wide range of rapidities using a magnetic spectrometer. The data have been analyzed in the Hanbury-Brown and Twiss (HBT) framework to extract source parameters as functions of the reaction plane as well as beam energy.

The hadroproduction of lepton pairs with mass Q and transverse momentum Q{sub T} can be described in perturbative QCD by the same partonic subprocesses as prompt photon production. They demonstrate that, like prompt photon production, lepton pair production is dominated by quark-gluon scattering in the region Q{sub T} > Q/2. This leads to sensitivity to the gluon density in kinematical regimes that are accessible both at collider and fixed target experiments while eliminating the theoretical and experimental uncertainties present in prompt photon production.

An overview is given of the current spectroscopic effort on the Livermore electron beam ion trap facilities. The effort focuses on four aspects: spectral line position, line intensity, temporal evolution, and line shape. Examples of line position measurements include studies of the K-shell transitions in heliumlike Kr{sup 34+} and the 2s-2p intrashell transitions in lithiumlike Th{sup 87+} and U{sup 89+}, which provide benchmark values for testing the theory of relativistic and quantum electrodynamical contributions in high-Z ions. Examples of line intensity measurements are provided by measurements of the electron-impact excitation and dielectronic recombination cross sections of heliumlike transition-metal ions Ti{sup 20+} through CO{sup 25+}. A discussion of radiative lifetime measurements of metastable levels in heliumlike ions is given to illustrate the time-resolved spectroscopy techniques in the microsecond range. The authors also present a measurement of the spectral lineshape that illustrates the very low ion temperatures that can be achieved in an EBIT.

Recent studies show that large negative ion densities exist in plasma processing discharges, including those of weakly electronegative gases such as SiH{sub 4} and CF{sub 4}. Also, there is strong evidence that the negative ions could be the precursors for particulate formation in processing discharges. Even though it is now well established that large concentrations of negative ions exist in processing discharges, and that they play a crucial role in such discharges, the source of such high negative ion densities has not been clarified. In particular, gases like SiH{sub 4} and CH{sub 4}, which are commonly used in processing discharges, attach electrons only weakly in their ground electronic states (see the references). Due to the lack of an alternative mechanism, the origin of large negative ion densities in such weakly electronegative gases has been frequently attributed to electron attachment to radicals (molecular fragments) or other byproducts produced in the discharge. This hypothesis had not been tested in direct electron attachment measurements.

Very low power, short-range microwave ''radar-like'' sensors can measure the motions and vibrations of internal human speech articulators as speech is produced. In these animate (and also in inanimate acoustic systems) microwave sensors can measure vibration information associated with excitation sources and other interfaces. These data, together with the corresponding acoustic data, enable the calculation of system transfer functions. This information appears to be useful for a surprisingly wide range of applications such as speech coding and recognition, speaker or object identification, speech and musical instrument synthesis, noise cancellation, and other applications.

Fibrous monoliths (FMs) of Si{sub 3}N{sub 4}/BN ({approx}85 vol% Si{sub 3}N{sub 4}/15 vol% BN) with three different cell architectures (unidirectional, 0{degree}/90{degree}, and {+-}45{degree}) were tested in four-point-bend mode under ambient conditions. The FM constituents (hot-pressed monolithic Si{sub 3}N{sub 4} and BN) were also characterized. The unidirectional Si{sub 3}N{sub 4}/BN FM demonstrated the best properties, with ultimate strength of 476 {+-} 30 MPa and work-of-fracture of 12.6 {+-} 1.9 kJ/m{sup 2}, while Si{sub 3}N{sub 4}/BN FM with {+-}45{degree} cell architecture had the lowest strength (175 {+-} 13 MPa) and work-of-fracture (2.7 {+-} 1.7 kJ/m{sup 2}). The 0{degree}/90{degree} FM had intermediate values of 379 {+-} 86 MPa and 4.9 {+-} 2.2 kJ/m{sup 2}. High work-of-fracture for the unidirectional Si{sub 3}N{sub 4}/BN was correlated to toughening mechanisms such as extensive delamination and crack deflection. Predictions for the elastic moduli of the Si{sub 3}N{sub 4}/BN FMs based on laminate theory correlated well with the observed elastic moduli for the unidirectional and 0{degree}/90{degree} Si{sub 3}N{sub 4}/BN FMs. However, large discrepancies were observed between predictions and observed values for the {+-}45{degree} Si{sub 3}N{sub 4}/BN FMs, possibly due to the increasing role of the BN phase on mechanical properties in these FMs. Mechanical properties of monolithic Si{sub …

Deep-inelastic diffractive scaling violations have provided fundamental insight into the QCD pomeron, suggesting a single gluon inner structure rather than that of a perturbative two-gluon bound state. This talk outlines a derivation of a high-energy, transverse momentum cut-off, confining solution of QCD. The pomeron, in first approximation, is a single reggeized gluon plus a ''wee parton'' component that compensates for the color and particle properties of the gluon. This solution corresponds to a super-critical phase of Reggeon Field Theory.

What do we mean by a chemical element? A chemical element is matter, all of whose atoms are alike in having the same positive charge on the nucleus and the same number of extra-nuclear electrons. As we shall see in the following elemental review, the origin of the chemical elements show a wide diversity with some of these elements having an origin in antiquity, other elements having been discovered within the past few hundred years and still others have been synthesized within the past fifty years via nuclear reactions on heavy elements since these other elements are unstable and radioactive and do not exist in nature.

Atomic Mass Evaluations have had a major impact on the values of the atomic weights for the twenty mononuclidic elements plus two elements, Thorium and Protactinium, which have no stable nuclides but a characteristic terrestrial isotopic composition. This paper reviews the history of the atomic weight values of these elements in the years, since the reference mass standard changed from {sup 16}O to {sup 12}C. There is a problem for Thorium, which is considered to have an abundance value of 100%, but is not treated as such in the Standard Atomic Weights' Table. Recommendations for handling the Standard Atomic Weight values for 2001 are presented.

A new facility has recently been completed at the National Renewable Energy Laboratory that allows full-scale dynamometer testing of wind turbine components, from generators to complete wind turbines. This facility is equipped with a 2.5 MW motor, gearbox, and variable speed drive system to deliver shaft torque. To simulate other aspects of wind turbine loading an MTS fatigue-rated loading system is fully integrated into the facility. This will allow actuators to cyclically load the structure in a variety of ways. Enron [formally Zond] Wind Corporation has installed the first test article in the facility to help mature the Z-750 series wind turbine design. Tests include brake and control system tuning, endurance testing of gear elements and bearings, and structural testing. Some aspects of the power converter will also be tested. This paper describes the Dynamometer Test Bed and its capabilities. Also, an overview of the Zond testing program is presented.

In this article, thermal modeling techniques are used to simulate ISOL targets irradiated with high power proton beams. Beam scattering effects, nuclear reactions and beam power deposition distributions in the target were computed with the Monte Carlo simulation code, GEANT4. The power density information was subsequently used as input to the finite element thermal analysis code, ANSYS, for extracting temperature distribution information for a variety of target materials. The principal objective of the studies was to evaluate techniques for more uniformly distributing beam deposited heat over the volumes of targets to levels compatible with their irradiation with the highest practical primary-beam power, and to use the preferred technique to design high power ISOL targets. The results suggest that radiation cooling, in combination, with primary beam manipulation, can be used to control temperatures in practically sized targets, to levels commensurate with irradiation with 1 GeV, 100 kW proton beams.

Recently, sensitivity and uncertainty (S/U) techniques have been used to determine the area of applicability (AOA) of critical experiments used for code and data validation. These techniques require the computation of energy-dependent sensitivity coefficients for multiple reaction types for every nuclide in each system included in the validation. The sensitivity coefficients, as used for this application, predict the relative change in the system multiplication factor due to a relative change in a given cross-section data component or material number density. Thus, a sensitivity coefficient, S, for some macroscopic cross section, {Sigma}, is expressed as S = {Sigma}/k {partial_derivative}k/{partial_derivative}{Sigma}, where k is the effective neutron multiplication factor for the system. The sensitivity coefficient for the density of a material is equivalent to that of the total macroscopic cross section. Two distinct techniques have been employed in Monte Carlo radiation transport codes for the computation of sensitivity coefficients. The first, and most commonly employed, is the differential sampling technique. The second is the adjoint-based perturbation theory approach. This paper briefly describes each technique and presents the results of a simple test case, pointing out discrepancies in the computed results and proposing a remedy to these discrepancies.

Article asserts that this research presents a novel and environmentally friendly approach for the synthesis of multifunctional nanobiocomposites for the efficient removal of toxic heavy metal and dye, as well as the disinfection of wastewater microorganisms. The synthesized bioinspired nanocomposite KAC-CS-AgNPs could be an innovative solution for effective and sustainable wastewater treatment and has great potential for commercial applications.