Status of large neodymium glass lasers (open access)

Status of large neodymium glass lasers

The elements of a Nd: Glass laser chain as it is constructed for fusion experiments are described. A brief overview of the ARGUS and SHIVA systems employing Nd lasers is given. (MOW)
Date: March 15, 1976
Creator: Glaze, J. A.; Simmons, W. W. & Hagen, W. F.
System: The UNT Digital Library
X-ray Spectropolarimetry of high temperature and high density plasma supported by LLNL Electron Beam Ion Trap Experiments (open access)

X-ray Spectropolarimetry of high temperature and high density plasma supported by LLNL Electron Beam Ion Trap Experiments

Plasma polarization spectroscopy work done by our group since the 3rd US-Japan PPS Workshop is overviewed. Theoretically, the polarization dependence on various electron distribution functions for He-like, Ne-like, and Ni-like x-ray transitions for a wide range of Z has been investigated. In particular, this study was focused on the polarization dependence for monoenergetic and steep electron distribution functions. The diagnostically important spectral lines and features of K-, L-, and M-shell ions were identified which can be used in x-ray spectropolarimetry of plasma. Importance of polarization-sensitive LLNL Electron Beam Ion Trap data is emphasized. The results of the UNR polarization-sensitive Ti and Mo x-pinch experiments are discussed.
Date: March 15, 2004
Creator: Shlyaptseva, A S; Kantsyrev, V L; Ouart, N D; Fedin, D A; Neill, P; Harris, C et al.
System: The UNT Digital Library
Strong field atomic physics in the mid-infrared (open access)

Strong field atomic physics in the mid-infrared

We examine strong field atomic physics in a wavelength region (3-4 microns) where very little work has previously been done. The soft photon energy allows the exploration of one-electron atoms with low binding energies (alkali metals). We find that photoionization spectra differ from rare gas studies at shorter wavelengths due to more complex ion core potentials. Harmonic generation is studied, and we find that harmonic bandwidths are consistent with theory and the possibility of compression to pulse widths much shorter than that of the driving pulse. Harmonic yields in the visible and W are sufficient for a complete study of their amplitude and phase characteristics.
Date: March 15, 2000
Creator: Sheehy, B.; Martin, J. D. D.; Clatterbuck, T. O.; Kim, D. W.; DiMauro, L. F.; Agostini, P. et al.
System: The UNT Digital Library
Associated Higgs Boson Production With Heavy Quarks. (open access)

Associated Higgs Boson Production With Heavy Quarks.

The production of a Higgs boson in association with a pair of e quarks will play a very important role at both hadron and lepton colliders. We review the status of theoretical predictions and their relevance to Higgs boson studies, with particular emphasis on the recently calculated NLO QCD corrections to the inclusive cross section for p{bar p}, pp {yields} t{bar t}h. We conclude by briefly discussing the case of exclusive b{bar b}h production and the potential of this process in revealing signals of new physics beyond the Standard Model.
Date: March 15, 2003
Creator: Dawson, S.; Orr, L. H.; Reina, L. & Wackeroth, D.
System: The UNT Digital Library
Freeeze-Out Dynamics at RHIC. (open access)

Freeeze-Out Dynamics at RHIC.

Investigation of the final hadronic state properties of ultra-relativistics pp and Au+Au collisions supplies information on freeze-out conditions at RHIC and possible insights into early stages of these collisions. A variety of particle spectra measured by STAR are studied within the framework of chemical and local kinetic equilibrium models. Here we present the extracted chemical and final kinetic freeze-out temperatures, strangeness saturation factor, final collective flow velocity, and the inferred flow velocity at chemical freeze-out. In light of those measurements we discuss dynamical evolution of the collision system.
Date: March 15, 2004
Creator: Barannikova, O.
System: The UNT Digital Library
Shock-induced alpha-omega structural phase transformation of titanium: A molecular-dynamics study (open access)

Shock-induced alpha-omega structural phase transformation of titanium: A molecular-dynamics study

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Date: March 15, 2004
Creator: Sadigh, B; Lenosky, T; Oppelstrup, T; Minich, R & Gilmer, G
System: The UNT Digital Library
EXPERIMENTAL VERIFICATION OF THE THREE-DIMENSIONAL THERMAL-HYDRAULIC MODELS IN THE BEST-ESTIMATE CODE BAGIRA. (open access)

EXPERIMENTAL VERIFICATION OF THE THREE-DIMENSIONAL THERMAL-HYDRAULIC MODELS IN THE BEST-ESTIMATE CODE BAGIRA.

In this paper we present verification results of the BAGIRA code that was performed using data from integral thermal-hydraulic experimental test facilities as well as data obtained from operating nuclear power plants. BAGIRA is a three-dimensional numerical best-estimate code that includes non-homogeneous modeling. Special consideration was given to the recently completed experimental data from the PSB-VVER integral test facility (EREC, Electrogorsk, Russia)--a new Russian large-scale four-loop unit, which has been designed to model the primary circuits of VVER-1000 type reactors. It is demonstrated that the code BAGIRA can be used to analyze nuclear reactor behavior under normal and accident conditions.
Date: March 15, 2004
Creator: KALINICHENKO,S. D. KROSHILIN,A. E. KROSHILIN,V. E. SMIRNOV,A. V. KOHUT,P.
System: The UNT Digital Library
Anisotropic Flow at RHIC. (open access)

Anisotropic Flow at RHIC.

We present the first measurement of directed flow (v{sub 1}) at the Relativistic Heavy Ion Collider (RHIC). v{sub 1} is found to be consistent with zero at pseudorapidities {eta} from -1.2 to 1.2, then rises to the level of a couple of percent over the range 2.4 < |{eta}| < 4. The latter observation is similar to that from NA49 if the SPS rapidities are shifted by the difference in beam rapidity between RHIC and SPS. We studied the evolution of elliptic flow from p + p collisions through d + Au collision, and onto Au + Au collisions. Measurements of higher harmonics are presented and discussed.
Date: March 15, 2004
Creator: Tang, A. H.
System: The UNT Digital Library
Atoms for Peace after Fifty Years (open access)

Atoms for Peace after Fifty Years

President Eisenhower's hopes for nuclear technology still resonate, but the challenges to fulfilling them are much different today. On December 8, 1953, President Eisenhower, returning from his meeting with the leaders of Britain and France at the Bermuda Summit, flew directly to New York to address the United Nations General Assembly. His presentation, known afterwards as the ''Atoms for Peace'' speech, was bold, broad, and visionary. Eisenhower highlighted dangers associated with the further spread of nuclear weapons and the end of the thermonuclear monopoly, but the president also pointed to opportunities. Earlier that year, Stalin had died and the Korean War armistice was signed. Talks on reunification of Austria were about to begin. The speech sought East-West engagement and outlined a framework for reducing nuclear threats to security while enhancing the civilian benefits of nuclear technology. One specific proposal offered to place surplus military fissile material under the control of an ''international atomic energy agency'' to be used for peaceful purposes, especially economic development. Eisenhower clearly recognized the complex interrelationships between different nuclear technologies and the risks and the benefits that accrue from each. The widespread use of civilian nuclear technology and absence of any use of a nuclear weapon …
Date: March 15, 2004
Creator: Joeck, N; Lehman, R; Vergino, E & Schock, R
System: The UNT Digital Library
PROTON - LAMBDA CORRELATIONS IN AU-AU COLLISIONS AT SQUARE ROOT NN = 200 GEV FROM THE STAR EXPERIMENT. (open access)

PROTON - LAMBDA CORRELATIONS IN AU-AU COLLISIONS AT SQUARE ROOT NN = 200 GEV FROM THE STAR EXPERIMENT.

The space-time evolution of the source of particles formed in the collision of nuclei can be studied through particle correlations. The STAR experiment is dedicated to study ultra-relativistic heavy ions collisions and allows to measure non-identical strange particle correlations. The source size can be extracted by studying p - {Lambda}, {bar p} - {bar {Lambda}}, {bar p} - {Lambda} and p - {bar {Lambda}} correlation functions. Strong interaction potential has been studied for these systems using an analytical model. Final State Interaction (FSI) parameters have been determined and has shown a significant annihilation process present in {bar p} - {Lambda} and p - {bar {Lambda}} systems not present in p - {Lambda} and {bar p} - {bar {Lambda}}.
Date: March 15, 2004
Creator: Renault, G.
System: The UNT Digital Library
Calculations of strong field multiphoton processes in alkali metal atoms (open access)

Calculations of strong field multiphoton processes in alkali metal atoms

The development of a new class of laser systems: capable of producing intense radiation in the mid-infrared (MIR) regime (photon energies between 0.3 and 0.4 eV), opens the possibility of observing multiphoton processes in a new class of systems with lower ionization potentials than those previously studied. Of particular interest are the alkali metal atoms, which are true one-(valence)-electron systems. We present theoretical calculations of above threshold ionization (ATI) and high harmonic generation (HHG) from alkali metal atoms subject to 3-4 {micro}m laser irradiation. The ATI calculations, which use a multiple gauge propagation method, show a striking dependence in the production of high-order photoelectrons on the electron-ion potential. The HHG calculations illustrate the importance of the strong ground-to-first excited state coupling in multiphoton processes in the alkali metals.
Date: March 15, 2000
Creator: Schafer, K. J.; Gaarde, M. B.; Kulander, K. C.; Sheehy, B. & DiMauro, L. F.
System: The UNT Digital Library
BRAHMS RESULTS IN THE CONTEXT OF SATURATION AND QUANTUM EVOLUTION. (open access)

BRAHMS RESULTS IN THE CONTEXT OF SATURATION AND QUANTUM EVOLUTION.

We report BRAHMS results from RHIC d+Au and p+p collisions at {radical}S{sub NN} = 200GeV. A remarkable change in the nuclear modification factor R{sub dAu} is seen as the pseudorapidity of the detected charged hadrons changes from zero at mid-rapidity to 3.2 at the most forward angle studied during the 2003 run. For pseudorapidity {eta} > 1 the suppression of the R{sub cp} factor is more pronounced in the sample of central events in contrast to the behavior at mid-rapidity where the central events show higher enhancement compared to a semi-central sample. These results are consistent with a saturated Au wave function strongly affected by quantum evolution at higher values of rapidity.
Date: March 15, 2004
Creator: DEBBE,R. (FOR THE BRAHMS COLLABORATION)
System: The UNT Digital Library
EVENT STRUCTURE AT RHIC FROM P-P TO AU-AU. (open access)

EVENT STRUCTURE AT RHIC FROM P-P TO AU-AU.

Several correlation analysis techniques are applied to p-p and Au-Au collisions at RHIC. Strong large-momentum-scale correlations are observed which can be related to local charge and momentum conservation during hadronization and to minijet (minimum-bias parton fragment) correlations.
Date: March 15, 2004
Creator: Trainor, T. A.
System: The UNT Digital Library
D phi detector (open access)

D phi detector

The D phi experiment is a recently approved effort at FERMILAB to study proton-antiproton collisions at 2 TeV. A powerful new detector has been designed for this experiment and is described. The D phi detector has been designed to optimize its discovery potential in the mass range where deviations from the Standard Model might be expected to manifest themselves. Rather than discussing the detector's response to particular hypothetical new states (Higgses, squarks, etc.), we focus here on more technical capabilities (leptons, jets, etc.). After a brief physics summary to motivate our technical choices, we consider the detector design subsystem by subsystem. 9 references.
Date: March 15, 1984
Creator: Aronson, S. H.
System: The UNT Digital Library
Microsats for On-Orbit Support Missions (open access)

Microsats for On-Orbit Support Missions

I appreciate the opportunity to address this conference and describe some of our work and plans for future space missions and capabilities. My presentation will consist of a short overview of our program, some potential missions and enabling technologies, as well as, a description of some of our test vehicles and ongoing docking experiments. The Micro-Satellite Technology Program at Lawrence Livermore National Laboratory is developing technologies for a new generation of a very highly capable autonomous microsats. A microsat is defined here as a vehicle that's less than 100 kilograms in mass. We're looking at a number of different microsat design configurations, between 0.5 to 1 meter in length and less than 40 kg in mass. You'll see several ground-test vehicles that we have been building that are modeled after potential future on-orbit systems. In order to have very aggressive missions, these microsats will require new integrated proximity operation sensors, advanced propulsion, avionics and guidance systems. Then to make this dream a reality a new approach to high fidelity ''hardware-in-the-loop'' ground testing, will be discussed that allows repeated tests with the same vehicle multiple times. This will enable you to ''get it right'' before going into space. I'll also show …
Date: March 15, 2001
Creator: Ledebuhr, A G
System: The UNT Digital Library
Exotic Particle Searches With Star at RHIC. (open access)

Exotic Particle Searches With Star at RHIC.

We present preliminary results of the STAR experiment at RHIC on exotic particle searches in minimum bias Au + Au collisions at {radical} s{sub NN} = 200 GeV. We observe a narrow peak at 1734 {+-} 0.5 {+-} 5 MeV in the {lambda}K{sub s}{sup 0} invariant mass with width consistent with the experimental resolution of about 6 MeV within the errors. The statistical significance can be quantified between 3 and 6 {sigma} depending on cuts and methods. If this peak corresponds to a real particle state it would be a candidate for the N{sup 0} or the {Xi}{sup 0} I = 1/2 pentaquark states.
Date: March 15, 2004
Creator: Kanaba, S.
System: The UNT Digital Library
ANALYSIS OF TWO-PHASE FLOW MODELS WITH TWO MOMENTUM EQUATIONS. (open access)

ANALYSIS OF TWO-PHASE FLOW MODELS WITH TWO MOMENTUM EQUATIONS.

An analysis of the standard system of differential equations describing multi-speed flows of multi-phase media is performed. It is proved that the Cauchy problem, as posed in most best-estimate thermal-hydraulic codes, results in unstable solutions and potentially unreliable description of many physical phenomena. A system of equations, free from instability effects, is developed allowing more rigorous numerical modeling.
Date: March 15, 2004
Creator: KROSHILIN,A. E. KROSHILIN,V. E. KOHUT,P.
System: The UNT Digital Library
Industrial Applications of Low Temperature Plasmas (open access)

Industrial Applications of Low Temperature Plasmas

The use of low temperature plasmas in industry is illustrated by the discussion of four applications, to lighting, displays, semiconductor manufacturing and pollution control. The type of plasma required for each application is described and typical materials are identified. The need to understand radical formation, ionization and metastable excitation within the discharge and the importance of surface reactions are stressed.
Date: March 15, 2001
Creator: Bardsley, J N
System: The UNT Digital Library
Operation of a Four-Cylinder 1.9L Propane Fueled HCCI Engine (open access)

Operation of a Four-Cylinder 1.9L Propane Fueled HCCI Engine

A four-cylinder 1.9 Volkswagen TDI Engine has been converted to run in Homogeneous Charge Compression Ignition (HCCI) mode. The stock configuration is a turbocharged direct injection Diesel engine. The combustion chamber has been modified by discarding the in-cylinder Diesel fuel injectors and replacing them with blank inserts (which contain pressure transducers). The stock pistons contain a reentrant bowl and have been retained for the tests reported here. The intake and exhaust manifolds have also been retained, but the turbocharger has been removed. A heater has been installed upstream of the intake manifold and fuel is added just downstream of this heater. The performance of this engine in naturally aspirated HCCI operation, subject to variable intake temperature and fuel flow rate, has been studied. The engine has been run with propane fuel at a constant speed of 1800 rpm. This work is intended to characterize the HCCI operation of the engine in this configuration that has been minimally modified from the base Diesel engine. The performance (BMEP, IMEP, efficiency, etc) and emissions (THC, CO, NOx) of the engine are presented, as are combustion process results based on heat release analysis of the pressure traces from each cylinder.
Date: March 15, 2001
Creator: Flowers, D.; Aceves, S. M.; Martinez-Frias, J.; Smith, J. R.; Au, M.; Girard, J. et al.
System: The UNT Digital Library
Nanostructured energetic materials derived from sol-gel chemistry (open access)

Nanostructured energetic materials derived from sol-gel chemistry

Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocrystalline ammonium perchlorate, the oxidizer, trapped within its pores. At optimum stoichiometry it has approximately the energy density of HMX. Transmission electron microscopy indicated no ammonium perchlorate crystallites larger than 20 nm while near-edge soft x-ray absorption microscopy showed that nitrogen was uniformly distributed, at least on the scale of less than 80 nm. Small-angle neutron scattering studies were conducted on the material. Those results were consistent with historical ones for this class of nanostructured materials. The average skeletal primary particle size was on the order of 2.7 nm, while the nanocomposite showed the growth of small 1 nm size crystals of ammonium perchlorate with some clustering to form particles greater than 10 nm.
Date: March 15, 2000
Creator: Simpson, R. L.; Tillotson, T. M.; Hrubesh, L. W. & Gash, A. E.
System: The UNT Digital Library
Actual Versus Predicted Impacts of Three Ethanol Plants on Aquatic and Terrestrial Resources (open access)

Actual Versus Predicted Impacts of Three Ethanol Plants on Aquatic and Terrestrial Resources

To help reduce US dependence on imported petroleum, Congress passed the Energy Security Act of 1980 (public Law 96-294). This legislation authorized the US Department of Energy (DOE) to promote expansion of the fuel alcohol industry through, among other measures, its Alcohol Fuels Loan Guarantee Program. Under this program, selected proposals for the conversion of plant biomass into fuel-grade ethanol would be granted loan guarantees. of 57 applications submitted for loan guarantees to build and operate ethanol fuel projects under this program, 11 were considered by DOE to have the greatest potential for satisfying DOE`s requirements and goals. In accordance with the National Environmental Policy Act (NEPA), DOE evaluated the potential impacts of proceeding with the Loan Guarantee Program in a programmatic environmental assessment (DOE 1981) that resulted in a finding of no significant impact (FANCY) (47 Federal Register 34, p. 7483). The following year, DOE conducted site-specific environmental assessments (EAs) for 10 of the proposed projects. These F-As predicted no significant environmental impacts from these projects. Eventually, three ethanol fuel projects received loan guarantees and were actually built: the Tennol Energy Company (Tennol; DOE 1982a) facility near Jasper in southeastern Tennessee; the Agrifuels Refining Corporation (Agrifuels; DOE 1985) facility …
Date: March 15, 1993
Creator: Eddlemon, Gerald K.; Webb, J. Warren; Hunsaker, Donald B., Jr. & Miller, Robert L.
System: The UNT Digital Library
A++/P++ array classes for architecture independent finite difference computations (open access)

A++/P++ array classes for architecture independent finite difference computations

Array class libraries have the potential to support development of a broad class of scientific computations. The high level array syntax coupled with machine dependent internal routines simplifies the structure of scientific codes and hides the details of particular machine architectures. Unfortunately, array class libraries generally suffer from recurring performance problems, making their use on high performance computers difficult to justify. In this paper, we discuss these performance issues for array class libraries and propose optimizations within A++/P++ to address them. Deferred evaluation in A++/P++ provides the information required for these optimizations. We present performance results on example finite difference computations which show that these performance problems can be overcome within array class libraries. The optimizations are equally applicable to more general scientific computations, thus establishing array class libraries as a viable program development strategy for scientific codes.
Date: March 15, 1994
Creator: Parsons, R. & Quinlan, D.
System: The UNT Digital Library
Quantized conic sections; quantum gravity (open access)

Quantized conic sections; quantum gravity

Starting from free relativistic particles whose position and velocity can only be measured to a precision < {Delta}r{Delta}v > {equivalent_to} {plus_minus} k/2 meter{sup 2}sec{sup {minus}1} , we use the relativistic conservation laws to define the relative motion of the coordinate r = r{sub 1} {minus} r{sub 2} of two particles of mass m{sub 1}, m{sub 2} and relative velocity v = {beta}c = {sub (k{sub 1} + k{sub 2}})/ {sup (k{sub 1} {minus} k{sub 2}}) in terms of conic section equation v{sup 2} = {Gamma} [2/r {plus_minus} 1/a] where ``+`` corresponds to hyperbolic and ``{minus}`` to elliptical trajectories. Equation is quantized by expressing Kepler`s Second Law as conservation of angular niomentum per unit mass in units of k. Principal quantum number is n {equivalent_to} j + {1/2} with``square`` {sub T{sup 2}}/{sup A{sup 2}} = (n {minus}1)nk{sup 2} {equivalent_to} {ell}{sub {circle_dot}}({ell}{sub {circle_dot}} + 1)k{sup 2}. Here {ell}{sub {circle_dot}} = n {minus} 1 is the angular momentumquantum number for circular orbits. In a sense, we obtain ``spin`` from this quantization. Since {Gamma}/a cannot reach c{sup 2} without predicting either circular or asymptotic velocities equal to the limiting velocity for particulate motion, we can also quantize velocities in terms of the principle quantum …
Date: March 15, 1993
Creator: Noyes, H. P.
System: The UNT Digital Library
Quantized conic sections; quantum gravity (open access)

Quantized conic sections; quantum gravity

Starting from free relativistic particles whose position and velocity can only be measured to a precision < [Delta]r[Delta]v > [equivalent to] [plus minus] k/2 meter[sup 2]sec[sup [minus]1] , we use the relativistic conservation laws to define the relative motion of the coordinate r = r[sub 1] [minus] r[sub 2] of two particles of mass m[sub 1], m[sub 2] and relative velocity v = [beta]c = [sub (k[sub 1] + k[sub 2]])/ [sup (k[sub 1] [minus] k[sub 2]]) in terms of conic section equation v[sup 2] = [Gamma] [2/r [plus minus] 1/a] where +'' corresponds to hyperbolic and [minus]'' to elliptical trajectories. Equation is quantized by expressing Kepler's Second Law as conservation of angular niomentum per unit mass in units of k. Principal quantum number is n [equivalent to] j + [1/2] with square'' [sub T[sup 2]]/[sup A[sup 2]] = (n [minus]1)nk[sup 2] [equivalent to] [ell][sub [circle dot]]([ell][sub [circle dot]] + 1)k[sup 2]. Here [ell][sub [circle dot]] = n [minus] 1 is the angular momentumquantum number for circular orbits. In a sense, we obtain spin'' from this quantization. Since [Gamma]/a cannot reach c[sup 2] without predicting either circular or asymptotic velocities equal to the limiting velocity for particulate motion, we can …
Date: March 15, 1993
Creator: Noyes, H. Pierre
System: The UNT Digital Library