This paper highlights a three-year project by an interdisciplinary team on a legacy F77 computational fluid dynamics code, with the aim of demonstrating that implicit unstructured grid simulations can execute at rates not far from those of explicit structured grid codes, provided attention is paid to data motion complexity and the reuse of data positioned at the levels of the memory hierarchy closest to the processor, in addition to traditional operation count complexity. The demonstration code is from NASA and the enabling parallel hardware and (freely available) software toolkit are from DOE, but the resulting methodology should be broadly applicable, and the hardware limitations exposed should allow programmers and vendors of parallel platforms to focus with greater encouragement on sparse codes with indirect addressing. This snapshot of ongoing work shows a performance of 15 microseconds per degree of freedom to steady-state convergence of Euler flow on a mesh with 2.8 million vertices using 3072 dual-processor nodes of ASCI Red, corresponding to a sustained floating-point rate of 0.227 Tflop/s.

Measurements of electrical resistivity as a function of temperature from 25 to 1,500 C were conducted on polycrystalline samples in the Mo-Si-B system. Single phase, or nearly single phase, samples were prepared for the following phases: Mo{sub 3}Si, Mo{sub 5}SiB{sub 2}, Mo{sub 5}Si{sub 3}B{sub x}, MoB, MoSi{sub 2}, and Mo{sub 5}Si{sub 3}. Thesis materials all exhibit resistivity values within a narrow range(4--22 x 10{sup {minus}7}{Omega}-m), and the low magnitude suggests these materials are semi-metals or low density of states metals. With the exception of MoSi{sub 2}, all single phase materials in this study were also found to have low temperature coefficient of resistivity(TCR) values. These values ranged from 2.10 x 10{sup {minus}10} to 4.74 x 10{sup {minus}10}{Omega}-m/{degree} C, and MoSi{sub 2} had a TCR of 13.77 x 10{sup {minus}10}{Omega}-m/{degree} C. The results from the single phase sample measurements were employed in a natural log rule-of-mixtures model to relate the individual phase resistivity values to those of multiphase composites. Three Mo-Si-B phase regions were analyzed: the binary Mo{sub 5}Si{sub 3}-MoSi{sub 2} system, the ternary phase field Mo{sub 5}Si{sub 3}B{sub x}MoB-MoSi{sub 2}, and the Mo{sub 3}Si-Mo{sub 5}SiB{sub 2}-Mo{sub 5} Si{sub 3}B{sub x} ternary region. The experimental data for samples in each of …

A novel method for containing a pure ion plasma at thermonuclear densities and temperatures has been modeled. The method combines the confinement properties of a Penning-Malmberg trap and some aspects of the magnetic field geometry of a pulsed theta-pinch. A conventional Penning trap can confine a uniform-density plasma of about 5x1011 cm-3 with a 30-Tesla magnetic field. However, if the axial field is ramped, a much higher local ion density can be obtained. Starting with a 107 cm-3 trapped deuterium plasma in a conventional Penning-Malmberg trap at the Brillouin limit (B = 0.6 Tesla), the field is ramped to 30 Tesla. Because the plasma is comprised of particles of only one sign of charge, transport losses are very low, i.e., the conductivity is high. As a result, the ramped field does not penetrate the plasma and a diamagnetic surface current is generated, with the ions being accelerated to relativistic velocities. To counteract the inward j x B forces from this induced current, additional ions are injected into the plasma along the axis to increase the density (and mutual electrostatic repulsion) of the target plasma. In the absence of the higher magnetic field in the center, the injected ions drift outward …

Several candidate container materials have been studied in modified Yucca Mountain (YM) ground water in the presence or absence of YM bacteria. YM bacteria increased corrosion rates by 5-6 fold in UNS G10200 carbon steel, and nearly 100-fold in UNS NO4400 Ni-Cu alloy. YM bacteria caused microbiologically influenced corrosion (MIC) through de-alloying or Ni-depletion of Ni-Cu alloy as evidenced by scanning electronic microscopy (SEM) and inductively coupled plasma spectroscopy (ICP) analysis. MIC rates of more corrosion-resistant alloys such as UNS NO6022 Ni-Cr- MO-W alloy, UN's NO6625 Ni-Cr-Mo alloy, and UNS S30400 stainless steel were measured below 0.05 umyr, however YM bacteria affected depletion of Cr and Fe relative to Ni in these materials. The chemical change on the metal surface caused by depletion was characterized in anodic polarization behavior. The anodic polarization behavior of depleted Ni-based alloys was similar to that of pure Ni. Key words: MIC, container materials, YM bacteria, de-alloying, Ni-depletion, Cr-depletion, polarization resistance, anodic polarization,

Principles of the Hall thruster with segmented electrodes are explored. A suitable vacuum facility was put into service. For purposes of comparison between segmented and conventional thruster approaches, a modular laboratory prototype thruster was designed and built. Under conventional operation, the thruster achieves state-of-the-art efficiencies (56% at 300 V and 890 W). Very preliminary results under operation with segmented electrodes are also described.

By definition a plasma is an electrically conducting gaseous mixture containing a significant concentration of cations and electrons. The Inductively Coupled Plasma (ICP) is an electrodeless discharge in a gas at atmospheric pressure. This discharge is an excellent one for vaporizing, atomizing, and ionizing elements. The early development of the ICP began in 1942 by Babat and then by Reed in the early 1960s. This was then followed by the pioneering work of Fassel and coworkers in the late 1960s. Commercial ICP spectrometers were introduced in the mid 1970s. A major breakthrough in the area of ICP took place in the early 1980s when the ICP was shown to be an excellent ion source for mass spectrometry.

A three-field model to study drift-resistive, low-frequency waves in low-beta, non-axisymmetric plasmas [J.L.V. Lewandowski, Phys. Plasmas, 4 (11) 4023 (1997)] is used to analyze the effect of the inhomogeneities in the stellarator magnetic field on the fastest (linear) growth rate, gamma. Extensive numerical calculations for a toroidal heliac show that not all Fourier components in the representation of the equilibrium configuration are important as far as gamma is concerned.

The work summarizes results of the authors' studies on the energetic ion transport induced by sawtooth oscillations in tokamaks. The main attention is paid to description of physical mechanisms responsible for the transport. In addition to overview, the work contains new material. The new results concern the resonant interaction of the particles and the electromagnetic field of the sawtooth crash. In particular, it is discovered that the dominant harmonic of the crash (m = n = 1) can lead to stochastic motion of particles having large orbit width (potatoes). Regular motion of potatoes and quasi-stagnation particles in the presence of an n = 1 mode is studied, and their characteristic displacements associated with quick switching on/off the mode are found.

This dissertation presented several results which add to the general knowledge base regarding organothiolates monolayer spontaneously adsorbed at gold films. Common to the body of this work is the use of voltammetric reductive resorption and variants of scanning probe microscopy to gain insight into the nature of the monolayer formation process as well as the resulting interface. The most significant result from this work is the success of using friction force microscopy to discriminate the end group orientation of monolayer chemisorbed at smooth gold surfaces with micrometer resolution (Chapter 4). The ability to detect the differences in the orientational disposition is demonstrated by the use PDMS polymer stamp to microcontact print an adlayer of n-alkanethiolate of length n in a predefine pattern onto a gold surface, followed by the solution deposition of a n-alkanethiol of n {+-} 1 to fill in the areas on the gold surface intentionally not coated by the stamping process. These two-component monolayers can be discriminated by using friction force microscopy which detects differences in friction contributed by the differences in the orientation of the terminal groups at surfaces. This success has recently led to the detection of the orientation differences at nanometer scale. Although the …

Under the likely scenario in which public support for nuclear energy remains low and fossil fuels continue to be abundant and cheap, government supported nuclear research centers must adapt their missions to ensure that they tackle problems of current significance. It will be critical to be multidisciplinary, to generate economic value, and to apply nuclear competencies to current problems. Addressing problems in nuclear safety, D and D, nuclear waste management, nonproliferation, isotope production are a few examples of current needs in the nuclear arena. Argonne's original mission, to develop nuclear reactor technology, was a critical need for the U.S. in 1946. It would be wise to recognize that this mission was a special instance of a more general one--to apply unique human and physical capital to long term, high risk technology development in response to society's needs. International collaboration will enhance the collective chances for success as the world moves into the 21st century.

Fast methods for separation and detection of important neurotransmitters and the releases in central nervous system (CNS) were developed. Enzyme based immunoassay combined with capillary electrophoresis was used to analyze the contents of amino acid neurotransmitters from single neuron cells. The release of amino acid neurotransmitters from neuron cultures was monitored by laser induced fluorescence imaging method. The release and signal transduction of adenosine triphosphate (ATP) in CNS was studied with sensitive luminescence imaging method. A new dual-enzyme on-column reaction method combined with capillary electrophoresis has been developed for determining the glutamate content in single cells. Detection was based on monitoring the laser-induced fluorescence of the reaction product NADH, and the measured fluorescence intensity was related to the concentration of glutamate in each cell. The detection limit of glutamate is down to 10{sup {minus}8} M level, which is 1 order of magnitude lower than the previously reported detection limit based on similar detection methods. The mass detection limit of a few attomoles is far superior to that of any other reports. Selectivity for glutamate is excellent over most of amino acids. The glutamate content in single human erythrocyte and baby rat brain neurons were determined with this method and results …

Toroidicity induced Alfven Eigenmode (TAE) stability in National Spherical Torus Experiment (NSTX) is analyzed using the improved NOVA-K code, which includes finite orbit width and Larmor radius effects and is able to predicts the saturation amplitude for the mode using the quasilinear theory. Broad spectrum of unstable global TAEs with different toroidal mode numbers is predicted. Due to the strong poloidal field and the presence of the magnetic well in NSTX better particle confinement in the presence of TAEs in comparison with tokamaks is illustrated making use of the ORBIT code.

This report summarizes the work done on Grant DE-FG03-95ER40916 over the period April 1, 1995 through March 31, 1999. Detailed progress have been submitted for the years through March 31, 1999. The primary project during this period was the D0 experiment at Fermilab and is discussed first. The last year of the period was an extension to complete the study of laser induced fluorescence in neon. This work is discussed in the section ''Detector R and D''.

Presented are the most recent jet fragmentation results from CDF: inclusive distributions of charged particle momenta and their k{sub T} in jets; average track multiplicities, as well as angular distributions of multiplicity flow, for a wide range of jet energies with E{sub T} from 40 to 300 GeV. The results are compared with Monte-Carlo and, when possible, analytical calculations performed in resumed perturbative QCD approximations (MLLA).

Results of high-energy synchrotrons radiation experiments are presented demonstrating the advantages of the atomic Pair Distribution Function technique in determining the structure of materials with high resolution.

This research involves using molten magnesium (Mg) to remove neodymium (Nd) from NdFeB magnet scrap by diffusion. The results show that liquid metal extraction of Nd may be a viable and inexpensive method for recovering the expensive rare earth element Nd for use in Mg castings.

Fact sheet written for the Inventions and Innovation Program about a new method for making steel strapping and strip from rod stock produced from scrap steel. There is a large movement in the American steel industry to utilize more recycled steel. Recycled steel melted in the electric arc furnaces of mini-mills is being used as the source of raw materials for an increasing number of products, largely due to its lower price. However, conventional processes for producing steel strapping and cold-rolled strip steel restrict manufacturers from using more than 50% recycled steel. In addition, steel strapping and cold-rolled strip steel traditionally require many production steps. They are produced from primary steel that has been cast into slab, heated, rolled to achieve the desired thickness, and slit to the desired width. The slitting process produces microcracks along the edge of the strapping or strip, which reduce tensile strength. A new continuous process produces steel strapping and 1/2 inch to 6 inch strip steel from the rod and strip stock made from scrap steel in mini-mills. The new process creates steel strapping and strip with improved strength and quality due to the absence of microcracks caused by the conventional slitting process. The …

The ORNL Heat Pump Design Model is a FORTRAN-IV computer program to predict the steady-state performance of conventional, vapor compression, electrically-driven, air-to-air heat pumps in both heating and cooling modes. This model is intended to serve as an analytical design tool for use by heat pump manufacturers, consulting engineers, research institutions, and universities in studies directed toward the improvement of heat pump performance. The Heat Pump Design Model allows the user to specify: system operating conditions, compressor characteristics, refrigerant flow control devices, fin-and-tube heat exchanger parameters, fan and indoor duct characteristics, and any of ten refrigerants. The model will compute: system capacity and COP (or EER), compressor and fan motor power consumptions, coil outlet air dry- and wet-bulb temperatures, air- and refrigerant-side pressure drops, a summary of the refrigerant-side states throughout the cycle, and overall compressor efficiencies and heat exchanger effectiveness. This report provides thorough documentation of how to use and/or modify the model. This is a revision of an earlier report containing miscellaneous corrections and information on availability and distribution of the model--including an interactive version.

Argonne National Laboratory has completed the construction of a Website for the US Department of Energy (DOE) that provides detailed information on salt caverns and their use for disposing of nonhazardous oil field wastes (NOW) and naturally occurring radioactive materials (NORM). Specific topics in the Website include the following: descriptions of salt deposits and salt caverns within the US, salt cavern construction methods, potential types of wastes, waste emplacement, regulatory issues, costs, carcinogenic and noncarcinogenic human health risks associated with postulated cavern release scenarios, new information on cavern disposal (e.g., upcoming meetings, regulatory issues, etc.), other studies supported by the National Petroleum Technology Office (NPTO) (e.g., considerations of site location, cavern stability, development issues, and bedded salt characterization in the Midland Basin), and links to other associated Web sites. In addition, the Website allows downloadable access to reports prepared on the topic that were funded by DOE. Because of the large quantities of NOW and NORM wastes generated annually by the oil industry, information presented on this Website is particularly interesting and valuable to project managers, regulators, and concerned citizens.

Imaging through biologic tissue relies on the discrimination of weakly scattered from multiply scattered photons. The degree of polarization can be used as the discrimination criterion by which to reject multiply scattered photons. Polarized light propagation through biologic tissue is typically studied using tissue phantoms consisting of dilute aqueous suspensions of microsphere. We show that, although such phantoms are designed to match the macroscopic scattering properties of tissue (i.e.. the scattering coefficient, {mu}{sub 3}, and scattering anisotropy, g), they do not accurately represent biologic tissue for polarization-sensitive studies. In common tissue phantoms, such as dilute Intralipid and dilute 1-{micro}m-diameter polystyrene microsphere suspensions, we find that linearly polarized light is depolarized more quickly than circularly polarized light. In dense tissue, however, where scatterers are often located in close proximity to one another, circularly polarized light is depolarized similar to or more quickly than linearly polarized light. We also demonstrate that polarized light propagates differently in dilute versus densely packed microsphere suspensions, which may account for the differences seen between polarized light propagation in common dilute tissue phantoms versus dense biologic tissue.

Using CARM (Computer Aided Reduction Method), a computer program that automates the mechanism reduction process, a variety of different reduced chemical kinetic mechanisms for ethylene and n-heptane have been generated. The reduced mechanisms have been compared to detailed chemistry calculations in simple homogeneous reactors and experiments. Reduced mechanisms for combustion of ethylene having as few as 10 species were found to give reasonable agreement with detailed chemistry over a range of stoichiometries and showed significant improvement over currently used global mechanisms. The performance of reduced mechanisms derived from a large detailed mechanism for n-heptane was compared to results from a reduced mechanism derived from a smaller semi-empirical mechanism. The semi-empirical mechanism was advantageous as a starting point for reduction for ignition delay, but not for PSR calculations. Reduced mechanisms with as few as 12 species gave excellent results for n-heptane/air PSR calculations but 16-25 or more species are needed to simulate n-heptane ignition delay.

On March 3 and 4, 1998, a visit was made to Oak Ridge National Laboratory (ORNL) by two officials from Ghana: Mr. I.K. Mintah, Acting Executive Director, Technical Wing, Ministry of Mines and Energy (MOME) and Dr. A.K. Ofosu-Ahenkorah, Coordinator, Energy Efficiency and Conservation Program, MOME. As a result of this visit, Dr. John S. Hsu of ORNL was invited by MOME to visit the Republic of Ghana in order to study the feasibility of improving electric motor service centers in Ghana.

An ion linac formed of superconducting rf cavities can provide a multi-beam driver accelerator for the production of nuclei far from stability. A multi-beam driver supports a wide variety of production reactions and methods. This paper outlines a concept for a 1.3 GV linac capable of delivering several hundred kilowatts of uranium beam at an energy of 400 MeV per nucleon. The linac would accelerate the full mass range of ions, and provide higher velocities for the lighter ions, for example 730 MeV for protons. The accelerator will consist of an ECR ion source injecting a normally conducting RFQ and four short IH structures, then feeding an array of more than 400 superconducting cavities of six different types, which range in frequency from 58 to 700 MHz. A novel feature of the linac is the acceleration of beams containing more than one charge state through portions of the linac, in order to maximize beam current for the heavier ions. Such operation is made feasible by the large transverse and longitudinal acceptance provided by the large aperture and high gradient which are characteristic of superconducting rf cavities.

A project was initiated at the Oak Ridge Y-12 Plant to implement software geometric error compensation within a PC-based machine tool controller from Manufacturing Data Systems, Inc. This project may be the first in which this type of compensation system was implemented in a commercially available machine tool controller totally in software. Previous implementations typically required using an external computer and hardware to interface through the position feedback loop of the controller because direct access to the controller software was not available. The test-bed machine for this project was a 2-axis Excello 921 T-base lathe. A mathematical error model of the lathe was created using homogeneous transformation matrices to relate the positions of the machine's slides to each other and to a world reference system. Equations describing the effects of the geometric errors were derived from the model. A software architecture was developed to support geometric error compensation for machine tools with up to 3 linear axes. Rotary axes were not supported in this implementation, but the developed architecture would not preclude their support in the future. Specific implementations will be dependent upon the configuration of the machine tool. A laser measuring system from Automated Precision, Inc. was used to …