The commonly known technology of field weakening for permanent-magnet (PM) motors is achieved by controlling the direct-axis current component through an inverter, without using mechanical variation of the air gap, a new machine approach for field weakening of PM machines by direct control of air-gap fluxes is introduced. The demagnetization situation due to field weakening is not an issue with this new method. In fact, the PMs are strengthened at field weakening. The field-weakening ratio can reach 1O:1 or higher. This technology is particularly useful for the PM generators and electric vehicle drives.

The Li(Si)/FeS{sub 2} and Li(Si)/CoS{sub 2} couples were evaluated with a low-melting LiBr-KBr-LiF eutectic and all-Li LiCl-LiBr-LiF electrolyte for a battery application that required both high energy and high power for short duration. Screening studies were carried out with 1.25 inch-dia. triple cells and with 10-cell batteries. The Li(Si)/LiCl-LiBr-LiF/CoS{sub 2} couple performed the best under the power load and the Li(Si)/LiCl-LiBr-LiF/FeS{sub 2} was better under the energy load. The former system was selected as the best overall performer for the wide range of temperatures for both loads, because of the higher thermal stability of CoS{sub 2}.

Six vitrification runs were conducted in the 5-inch Cylindrical Induction Melter (CIM5) to evaluate the system's ability to process potential product loading extremes that may be encountered during Am/Cm vitrification in the F-Canyon MPPF. This evaluation demonstrates the CIM5 system's ability to vitrify feed streams of the specified extremes.

A lattice-Monte Carlo approach was developed to simulate ferroelectric domain behavior. The model utilizes a Hamiltonian for the total energy that includes electrostatic terms (involving dipole-dipole interactions, local polarization gradients, and applied electric field), and elastic strain energy. The contributions of these energy components to the domain structure and to the overall applied field response of the system were examined. In general, the model exhibited domain structure characteristics consistent with those observed in a tetragonally distorted ferroelectric. Good qualitative agreement between the appearance of simulated electrical hysteresis loops and those characteristic of real ferroelectric materials was found.

The authors used micro-Raman spectroscopy to monitor the ferroelectric (FE) to antiferroelectric (AFE) phase transition in PZT ceramic bars during the application of uniaxial stress. They designed and constructed a simple loading device, which can apply sufficient uniaxial force to transform reasonably large ceramic bars while being small enough to fit on the mechanical stage of the microscope used for Raman analysis. Raman spectra of individual grains in ceramic PZT bars were obtained as the stress on the bar was increased in increments. At the same time gauges attached to the PZT bar recorded axial and lateral strains induced by the applied stress. The Raman spectra were used to calculate an FE coordinate, which is related to the fraction of FE phase present. The authors present data showing changes in the FE coordinates of individual PZT grains and correlate these changes to stress-strain data, which plot the macroscopic evolution of the FE-to-AFE transformation. Their data indicates that the FE-to-AFE transformation does not occur simultaneously for all PZT grains but that grains react individually to local conditions.

Monthly newsletter discussing news and activities related to the Atmospheric Radiation Measurement Program, articles about weather and atmospheric phenomena, and other related topics.

Amorphous carbon films with an s p{sup 3} content up to 25% and a negligible amount of hydrogen have been grown by evaporation of graphite and concurrent Ar{sup +} ion bombardment. The s p{sup 3} content is maximized for Ar{sup +} energies between 200 and 300 eV following a subplantation mechanism. Higher ion energies deteriorate the film due to sputtering and heating processes. The hardness of the films increases in the optimal assisting range from 8 to 18 GPa, and is explained by the crosslinking of graphitic planes through s p {sup 3} connecting site.

A flywheel is an electromechanical storage system in which energy is stored in the kinetic energy of a rotating mass. Flywheel systems under development include those with steel flywheel rotors and resin/glass or resin/carbon-fiber composite rotors. The mechanics of energy storage in a flywheel system are common to both steel- and composite-rotor flywheels. In both systems, the momentum of the rotating rotor stores energy. The rotor contains a motor/generator that converts energy between electrical and mechanical forms. In both types of systems, the rotor operates in a vacuum and spins on bearings to reduce friction and increase efficiency. Steel-rotor systems rely mostly on the mass of the rotor to store energy while composite flywheels rely mostly on speed. During charging, an electric current flows through the motor increasing the speed of the flywheel. During discharge, the generator produces current flow out of the system slowing the wheel down. The basic characteristics of a Flywheel system are shown. Steel flywheel systems are currently being marketed in the US and Germany and can be connected in parallel to provide greater power if required. Sizes range from 40kW to 1.6MW for times of 5--120 seconds. At this time sales are limited but growing. …

This report summarizes results of an analysis of hydride-related degradation of commercial spent-nuclear-fuel cladding under repository conditions. Based on applicable laboratory data on critical stress intensity obtained under isothermal conditions, occurrence of delayed hydride cracking from the inner-diameter side of cladding is concluded to be extremely unlikely. The key process for potential initiation of delayed hydride cracking at the outer-diameter side is long-term microstructural evolution near the localized regions of concentrated hydrides, i.e., nucleation, growth, and cracking of hydride blisters. Such locally concentrated hydrides are, however, limited to some high-burnup cladding only, and the potential for crack initiation and propagation at the outer-diameter side is expected to be insignificant for most spent fuels. Some degree of hydride reorientation could occur in high-burnup spent-fuel cladding. However, even if hydride reorientation occurs, accompanying stress-rupture failure in spent-fuel cladding is unlikely to occur.

The author begins by discussing the history of nuclear power development in the US. He discusses the challenges for nuclear power such as the proliferation of weapons material, waste management, economics, and safety. He then discusses the future for nuclear power, specifically advanced reactor development. People can all be thankful for nuclear power, for it may well be essential to the long term survival of civilization. Within the seeds of its potential for great good, are also the seeds for great harm. People must ensure that it is applied for great good. What is not in question is whether people can live without it, they cannot. United States leadership is crucial in determining how this technology is developed and applied. The size and capability of the United States technical community is decreasing, a trend that cannot be allowed to continue. It is the author's belief that in the future, the need, the vision and the confidence in nuclear power will be restored, but only if the US addresses the immediate challenges. It is a national challenge worthy of the best people this nation has to offer.

The use of vacuum multifoil (VMF) container for thermal insulation in long-life thermal batteries was investigated in a proof-of-concept demonstration. An InvenTek-designed VMF container 4.9 inches in diameter by 10 inches long was used with an internally heated aluminum block, to simulate a thermal-battery stack. The block was heated to 525 C or 600 C and allowed to cool while monitoring the temperature of the block and the external case at three locations with time. The data indicate that it should be possible to build an equivalent-sized thermal battery that should last up to six hours, which would meet the requirements for a long-life sonobuoy application.

Hemispherical reflectance and internal quantum efficiency measurements have been employed to evaluate the response of Si nanostructured surfaces formed by using random and periodic reactive ion etching techniques. Random RIE-textured surfaces have demonstrated solar weighted reflectance of {approx} 3% over 300--1,200-nm spectral range even without the benefit of anti-reflection films. Random RIE-texturing has been found to be applicable over large areas ({approximately} 180 cm{sup 2}) of both single and multicrystalline Si surfaces. Due to the surface contamination and plasma-induced damage, RIE-textured surfaces did not initially provide increased short circuit current as expected from the enhanced absorption. Improved processing combined with wet-chemical damage removal etches resulted in significant improvement in the short circuit current with IQEs comparable to the random, wet-chemically textured surfaces. An interesting feature of the RIE-textured surfaces was their superior performance in the near IR spectral range. The response of RIE-textured periodic surfaces can be broadly classified into three distinct regimes. One-dimensional grating structures with triangular profiles are characterized by exceptionally low, polarization-independent reflective behavior. The reflectance response of such surfaces is similar to a graded-index anti-reflection film. The IQE response from these surfaces is severely degraded in the UV-Visible spectral region due to plasma-induced surface damage. One-dimensional …

As computational needs for structural finite element analysis increase, a robust implicit structural dynamics code is needed which can handle millions of degrees of freedom in the model and produce results with quick turn around time. A parallel code is needed to avoid limitations of serial platforms. Salinas is an implicit structural dynamics code specifically designed for massively parallel platforms. It computes the structural response of very large complex structures and provides solutions faster than any existing serial machine. This paper gives a current status of Salinas and uses demonstration problems to show Salinas' performance.

This is a multiyear experimental research program focused on improving relevant material properties of high-T{sub c} superconductors (HTSs) and on development of fabrication methods that can be transferred to industry for production of commercial conductors. The development of teaming relationships through agreements with industrial partners is a key element of the Argonne program. Recent results are presented on YBa{sub 2}Cu{sub 3}O{sub x} (Y-123) coated conductors, sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) tapes, and applications development.

Maintaining the integrity of the reactor pressure vessel (RPV) in a light-water-cooled nuclear power plant is crucial in preventing and controlling severe accidents that have the potential for major contamination release. Because the RPV is the only key safety-related component of the plant for which a redundant backup system does not exist, it is imperative to fully understand the degree of irradiation-induced degradation of the RPV's fracture resistance that occurs during service. For this reason, the Heavy-Section Steel Irradiation (HSSI) Program has been established.

The SCDAP/RELAP5 code is being developed at the Idaho National Engineering and Environmental Laboratory under the primary sponsorship of the U.S. Nuclear Regulatory Commission (NRC) to provide best-estimate transient simulations of light water reactor coolant systems during severe accidents. This paper describes the modeling approach used in the SCDAP/RELAP5 code to calculate fluid heat transfer and flow losses through porous debris that has accumulated in the vessel lower head and core regions during the latter stages of a severe accident. The implementation of heat transfer and flow loss correlations into the code is discussed, and calculations performed to assess the validity of the modeling approach are described. The different modes of heat transfer in porous debris include: (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, (5) film boiling, and (6) transition from film boiling to convection to vapor. The correlations for flow losses in porous debris include frictional and form losses. The correlations for flow losses were integrated into the momentum equations in the RELAP5 part of the code. Since RELAP5 is a very general non-homogeneous non-equilibrium thermal-hydraulics code, the resulting modeling methodology is applicable to a wide range of debris thermal-hydraulic …

The authors report results from an experimental study that examines the influence of sintering and microstructure on ash deposit thermal conductivity. The measurements are made using a technique developed to make in situ, time-resolved measurements of the effective thermal conductivity of ash deposits formed under conditions that closely replicate those found in the convective pass of a commercial boiler. The technique is designed to minimize the disturbance of the natural deposit microstructure. The initial stages of sintering and densification are accompanied by an increase in deposit thermal conductivity. Subsequent sintering continues to densify the deposit, but has little effect on deposit thermal conductivity. SEM analyses indicates that sintering creates a layered deposit structure with a relatively unsintered innermost layer. They hypothesize that this unsintered layer largely determines the overall deposit thermal conductivity. A theoretical model that treats a deposit as a two-layered material predicts the observed trends in thermal conductivity.

Refrigerator energy use is a dominant component of total energy use for many low-income households. Poorly operating or inefficient refrigerators can place an unnecessary financial burden on those households or the public agencies that pay their electricity bills, such as housing authorities. This paper presents an analytic tool that is low cost and easy to use. The procedure can be implemented with minimal staff training. The tool enables housing providers or weatherization agencies to identify poorly operating or high use refrigerators and target them for replacement or repair. The use of the procedure is illustrated, and its value for participants in a bulk refrigerator purchase and replacement program is discussed.

Front-end sampling or preconcentration is an important analytical technique and will be crucial to the success of many microanalytical detector systems. This paper describes a microfabricated planar preconcentrator ideal for integration with microanalytical systems. The device incorporates a surfactant templated sol gel adsorbent layer deposited on a microhotplate to achieve efficient analyte collection, and rapid, efficient thermal desorption. Concentration factors of 100--500 for dimethyl methyl phosphonate (DMMP) have been achieved with this device, while selectivities to interfering compounds greater than a factor of 25 have been demonstrated. Device performance will be compared with conventional preconcentrators, and the effects of system flow rate, flow channel geometry and collection time will be presented. A physical model of adsorption/desorption from the device will be reviewed and compared with experiment, while numerical simulation of flow over the device will be described.

The main aim of National Spherical Torus Experiment (NSTX) is to establish the fusion physics principles of the innovative spherical torus (ST) concept. Physics outcome of the NSTX research program is relevant to near-term applications such as the Volume Neutron Source (VNS) and burning plasmas, and future applications such as the pilot and power plants. The NSTX device began plasma operations in February 1999 and the plasma current was successfully ramped up to the design value of 1 million amperes (MA) on December 14, 1999. The CHI (Coaxial Helicity Injection) and HHFW (High Harmonic Fast Wave) experiments have also started. Stable CHI discharges of up to 133 kA and 130-msec duration have been produced using 20 kA of injected current. Using eight antennas connected to two transmitters, up to 2 MW of HHFW power was successfully coupled to the plasma. The Neutral-beam Injection (NBI) heating system and associated NBI-based diagnostics such as the Charge-exchange Recombination Spectrometer (CHERS) will be operational in October 2000.

This paper will concentrate on the progression of the bioassay and dose evaluation programs at Savannah River Site.

Sandia National Laboratories has learned through their process of technology transfer that not all high tech transfers are alike. They are not alike by the nature of the customers involved, the process of becoming involved with these customers and finally and most importantly the very nature of the technology itself. Here they focus on technology transfer in the microsystems arena and specifically the sacrificial surface version of microsystems. They have learned and helped others learn that many MEMS applications are best realized through the use of surface micromachining (SMM). This is because SMM builds on the substantial integrated circuit industry. In this paper they review Sandia's process for transferring a disruptive MEMS technology in numerous cases.

In this note, the authors present the recipe recommended by the Search Limits Committee for the construction of confidence intervals for the use of D0 collaboration. In another note, currently in preparation, they present the rationale for this recipe, a critique of the current literature on this topic, and several examples of the use of the method. This note is intended to fill the need of the collaboration to have a reference available until the more complete note is finished. Section 2 introduces the notation used in this note, and Section 3 contains the suggested recipe.

This report will be revised upon completion of current testing investigating the radiolytic stability of additional energetic materials and the analysis of tank farm samples for volatile and semi-volatile organic compounds.