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Correlation and prediction of partition coefficients between the gas phase and water, and the solvents dodecane and undecane (open access)

Correlation and prediction of partition coefficients between the gas phase and water, and the solvents dodecane and undecane

Article on the correlation and prediction of partition coefficients between the gas phase and water, and the solvents dodecane and undecane.
Date: October 29, 2004
Creator: Abraham, M. H. (Michael H.) & Acree, William E. (William Eugene)
System: The UNT Digital Library
A Detailed Chemical Kinetic Analysis of Low Temperature Non-Sooting Diesel Combustion (open access)

A Detailed Chemical Kinetic Analysis of Low Temperature Non-Sooting Diesel Combustion

We have developed a model of the diesel fuel injection process for application to analysis of low temperature non-sooting combustion. The model uses a simplified mixing correlation and detailed chemical kinetics, and analyzes a parcel of fuel as it moves along the fuel jet, from injection into evaporation and ignition. The model predicts chemical composition and soot precursors, and is applied at conditions that result in low temperature non-sooting combustion. Production of soot precursors is the first step toward production of soot, and modeling precursor production is expected to give insight into the overall evolution of soot inside the engine. The results of the analysis show that the model has been successful in describing many of the observed characteristics of low temperature combustion. The model predicts results that are qualitatively similar to those obtained for soot formation experiments at conditions in which the EGR rate is increased from zero to very high values as the fueling rate is kept constant. The model also describes the two paths to achieve non-sooting combustion. The first is smokeless rich combustion and the second is modulated kinetics (MK). The importance of the temperature after ignition and the equivalence ratio at the time of ignition …
Date: October 1, 2004
Creator: Aceves, S M & Flowers, D L
System: The UNT Digital Library
Computational Modeling of K-shell Argon Spectra from Z-pinch Dynamic Hohlraum Experiments (open access)

Computational Modeling of K-shell Argon Spectra from Z-pinch Dynamic Hohlraum Experiments

Z-pinch dynamic hohlraum experiments on the Z-Machine at Sandia National Laboratories measured K-shell argon spectra using a focusing spectrometer with spatial resolution. The spectra are modeled using Hullac atomic data input, Cretin nonlocal thermodynamic equilibrium (nlte) atomic kinetics and radiative transfer calculations, and Dakota optimization capabilities. Hullac provides atomic structure and cross section data for Ar XIX, Ar XXVIII (n=1 (illegible) 5), Ar XXVII (n=1 (illegible) 10), and Ar XXVI (n=1 (illegible) 5), where n is the principal quantum number. Cretin calculates the area-integrated spectral intensity escaping an argon doped Dcapsule as a function of electron density, electron temperature, and capsule radius. Dakota optimizes the plasma properties for the best to the measured spectrum by minimizing an objective function comprise of argon spectral line ratios and full-width at half-maximums (fwhms). We highlight the framework of this general spectroscopic capability and discuss the extension to magnetized plasmas using Totalb spectral line shapes.
Date: October 27, 2004
Creator: Adams, M L; Sinars, D B; Scott, H A; Brandon, S T; Chung, H K & Lee, R W
System: The UNT Digital Library
2nd International Conference on Pathways, Networks, and Systems: Theory and Experiments (open access)

2nd International Conference on Pathways, Networks, and Systems: Theory and Experiments

With the availability of whole genome sequences, research attention shifts from gene sequences and genome content to protein functions and systems biology. Genes comprise a major component of the ''parts list'' that is required for building and maintaining of living organisms. Genome DNA sequences reveal the genetic inventory for a rapidly increasing number of species. Defining and interpreting the instruction manual for protein functions, individually and collectively, is the emerging challenge. Defining protein functions is a complex problem because each gene typically encodes several distinct proteins. As a result, the protein inventory includes as many as 100,000 distinct proteins. Protein functions can vary with developmental stage, anatomical location, and environmental context. Like the problem of sequencing the human genome, the multidimensional nature of protein functions in time, space and context constitutes one of the ''big'' problems in biomedical research. Resolving this problem is key to revolutionizing health care where a deep understanding of complex biological systems will lead to more powerful and specific ways to treat, and perhaps, even prevent birth defects and adult diseases. The meeting addressed the above issues.
Date: October 1, 2004
Creator: Aegean Conferences
System: The UNT Digital Library
Realizing the Opportunities of Neutron Cross Section Measurements at RIA (open access)

Realizing the Opportunities of Neutron Cross Section Measurements at RIA

The Rare Isotope Accelerator will produce many isotopes at never before seen rates. This will allow for the first time measurements on isotopes very far from stability and new measurement opportunities for unstable nuclei near stability. In fact, the production rates are such that it should be possible to collect 10 micrograms of many isotopes with a half-life of 1 day or more. This ability to make targets of short-lived nuclei enables the possibility of making neutron cross-section measurements important to the astrophysics and the stockpile stewardship communities. But to fully realize this opportunity, the appropriate infrastructure must be included at the RIA facility. This includes isotope harvesting capabilities, radiochemical areas for processing collected material, and an intense, ''mono-energetic'', tunable neutron source. As such, we have been developing a design for neutron source facility to be included at the RIA site. This facility would produce neutrons via intense beams of deuterons and protons on a variety of targets. The facility would also include the necessary radiochemical facilities for target processing. These infrastructure needs will be discussed in addition to the methods that would be employed at RIA for measuring these neutron cross-sections.
Date: October 13, 2004
Creator: Ahle, L; Hausmann, M; Reifarth, R; Roberts, K; Roeben, M; Rusnak, B et al.
System: The UNT Digital Library
Non-Poisson Dichotomous Noise: Higher-Order Correlation Functions and Aging (open access)

Non-Poisson Dichotomous Noise: Higher-Order Correlation Functions and Aging

This article discusses non-Poisson dichotomous noise and higher-order correlation functions and aging.
Date: October 26, 2004
Creator: Allegrini, Paolo; Grigolini, Paolo; Palatella, Luigi & West, Bruce J.
System: The UNT Digital Library
THE IMPACT OF THE GLOBAL NUCLEAR SAFETY REGIME IN BRAZIL (open access)

THE IMPACT OF THE GLOBAL NUCLEAR SAFETY REGIME IN BRAZIL

A turning point of the world nuclear industry with respect to safety occurred due to the accident at Chernobyl, in 1986. A side from the tragic personal losses and the enormous financial damage, the Chernobyl accident has literally demonstrated that ''a nuclear accident anywhere is an accident everywhere''. The impact was felt immediately by the nuclear industry, with plant cancellations (e.g. Austria), elimination of national programs (e.g. Italy) and general construction delays. However, the reaction of the nuclear industry was equally immediate, which led to the proposal and establishment of a Global Nuclear Safety Regime. This regime is composed of biding international safety conventions, globally accepted safety standard, and a voluntary peer review system. In a previous work, the author has presented in detail the components of this Regime, and briefly discussed its impact in the Brazilian nuclear power organizations, including the Regulatory Body. This work, on the opposite, briefly reviews the Global Nuclear Safety Regime, and concentrates in detail in the discussion of its impact in Brazil, showing how it has produced some changes, and where the peer pressure regime has failed to produce real results.
Date: October 6, 2004
Creator: Almeida, C.
System: The UNT Digital Library
IRIS Reactor a Suitable Option to Provide Energy and Water Desalination for the Mexican Northwest Region (open access)

IRIS Reactor a Suitable Option to Provide Energy and Water Desalination for the Mexican Northwest Region

The Northwest region of Mexico has a deficit of potable water, along this necessity is the region growth, which requires of additional energy capacity. The IRIS reactor offers a very suitable source of energy given its modular size of 300 MWe and it can be coupled with a desalination plant to provide the potable water for human consumption, agriculture and industry. The present paper assess the water and energy requirements for the Northwest region of Mexico and how the deployment of the IRIS reactor can satisfy those necessities. The possible sites for deployment of Nuclear Reactors are considered given the seismic constraints and the closeness of the sea for external cooling. And in the other hand, the size of the desalination plant and the type of desalination process are assessed accordingly with the water deficit of the region.
Date: October 3, 2004
Creator: Alonso, G.; Ramirez, R.; Gomez, C. & Viais, J.
System: The UNT Digital Library
3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor (open access)

3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor

The DOE Advanced Fuel Cycle Initiative and Generation IV reactor programs are developing new fuel types for use in the current Light Water Reactors and future advanced reactor concepts. The Advanced Gas Reactor program is planning to test fuel to be used in the Next Generation Nuclear Plant (NGNP) nuclear reactor. Preliminary information for assessing performance of the fuel will be obtained from irradiations performed in the Advanced Test Reactor large ''B'' experimental facility. A test configuration has been identified for demonstrating fuel types typical of gas cooled reactors or fast reactors that may play a role in closing the fuel cycle or increasing efficiency via high temperature operation Plans are to have 6 capsules, each containing 12 compacts, for the test configuration. Each capsule will have its own temperature control system. Passing a helium-neon gas through the void regions between the fuel compacts and the graphite carrier and between the graphite carrier and the capsule wall will control temperature. This design with three compacts per axial level was evaluated for thermal performance to ascertain the temperature distributions in the capsule and test specimens with heating rates that encompass the range of initial heat generation rates.
Date: October 6, 2004
Creator: Ambrosek, Richard G.; Chang, Gray S. & Utterbeck, Debby J.
System: The UNT Digital Library
3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor (open access)

3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor

The DOE Advanced Fuel Cycle Initiative and Generation IV reactor programs are developing new fuel types for use in the current Light Water Reactors and future advanced reactor concepts. The Advanced Gas Reactor program is planning to test fuel to be used in the Next Generation Nuclear Plant (NGNP) nuclear reactor. Preliminary information for assessing performance of the fuel will be obtained from irradiations performed in the Advanced Test Reactor large “B” experimental facility. A test configurations has been identified for demonstrating fuel types typical of gas cooled reactors or fast reactors that may play a role in closing the fuel cycle or increasing efficiency via high temperature operation Plans are to have 6 capsules, each containing 12 compacts, for the test configuration. Each capsule will have its own temperature control system. Passing a helium-neon gas through the void regions between the fuel compacts and the graphite carrier and between the graphite carrier and the capsule wall will control temperature. This design with three compacts per axial level was evaluated for thermal performance to ascertain the temperature distributions in the capsule and test specimens with heating rates that encompass the range of initial heat generation rates.
Date: October 1, 2004
Creator: Ambrosek, Richard; Chang, Gray & Utterbeck, Debra
System: The UNT Digital Library
Hohlraum-driven ignition-like double-shell implosions on the Omega laser facility (open access)

Hohlraum-driven ignition-like double-shell implosions on the Omega laser facility

High-convergence ignition-like double-shell implosion experiments have been performed on the Omega laser facility [T.R. Boehly et al., Opt. Commun. 133, 495 (1997)] using cylindrical gold hohlraums with 40 drive beams. Repeatable, dominant primary (2.45 MeV) neutron production from the mix-susceptible compressional phase of a double-shell implosion, using fall-line design optimization and exacting fabrication standards, is experimentally inferred from time-resolved core x-ray imaging. Effective control of fuel-pusher mix during final compression is essential for achieving noncryogenic ignition with double-shell targets on the National Ignition Facility [Paisner et al., Laser Focus World 30, 75 (1994)].
Date: October 1, 2004
Creator: Amendt, P.; Robey, H. F.; Park, H. S.; Tipton, R. E.; Turner, R. E.; Milovich, J. L. et al.
System: The UNT Digital Library
VELOCITY BUNCHING OF HIGH-BRIGHTNESS ELECTRON BEAMS (open access)

VELOCITY BUNCHING OF HIGH-BRIGHTNESS ELECTRON BEAMS

Velocity bunching has been recently proposed as a tool for compressing electron beam pulses in modern high brightness photoinjector sources. This tool is familiar from earlier schemes implemented for bunching dc electron sources, but presents peculiar challenges when applied to high current, low emittance beams from photoinjectors. The main difficulty foreseen is control of emittance oscillations in the beam in this scheme, which can be naturally considered as an extension of the emittance compensation process at moderate energies. This paper presents two scenarios in which velocity bunching, combined with emittance control, is to play a role in nascent projects. The first is termed ballistic bunching, where the changing of relative particle velocities and positions occur in distinct regions, a short high gradient linac, and a drift length. This scenario is discussed in the context of the proposed ORION photoinjector. Simulations are used to explore the relationship between the degree of bunching, and the emittance compensation process. Experimental measurements performed at the UCLA Neptune Laboratory of the surprisingly robust bunching process, as well as accompanying deleterious transverse effects, are presented. An unanticipated mechanism for emittance growth in bends for highly momentum chirped beam was identified and studied in these experiments. The …
Date: October 15, 2004
Creator: Anderson, S. G.; Musumeci, P.; Rosenzweig, J. B.; Brown, W. J.; England, R. J.; Ferrario, M. et al.
System: The UNT Digital Library
Measurements of the Optical Constants of Scandium in the 50-1300eV Range. (open access)

Measurements of the Optical Constants of Scandium in the 50-1300eV Range.

Scandium containing multilayers have been produced with very high reflectivity in the soft x-ray spectrum. Accurate optical constants are required in order to model the multilayer reflectivity. Since there are relatively few measurements of the optical constants of Scandium in the soft x-ray region we have performed measurements over the energy range of 50-1,300 eV. Thin films of Scandium were deposited by ion-assisted magnetron sputtering at Linkoping University and DC Magnetron sputtering at CXRO. Transmission measurements were performed at the Advanced Light Source beamline 6.3.2. The absorption coefficient was deduced from the measurements and the dispersive part of the index of refraction was obtained using the Kramers-Kronig relation. The measured optical constants are used to model the near-normal incidence reflectivity of Cr/Sc multilayers near the Sc L{sub 2,3} edge.
Date: October 3, 2004
Creator: Aquila, A. L.; Salmassi, F.; Gullikson, E. M.; Eriksson, F. & Birch, J.
System: The UNT Digital Library
High-Resolution Compton-Suppressed CZT Detector for Fission Products Identification (open access)

High-Resolution Compton-Suppressed CZT Detector for Fission Products Identification

Room temperature semiconductor CdZnTe (CZT) detectors are currently limited to total detector volumes of 1-2 cm3, which is dictated by the poor charge transport characteristics. Because of this size limitation one of the problems in accurately determining isotope identification is the enormous background from the Compton scattering events. Eliminating this background will not only increase the sensitivity and accuracy of measurements but also help us to resolve peaks buried under the background and peaks in close vicinity of others. We are currently developing a fission products detection system based on the Compton-suppressed CZT detector. In this application, the detection system is required to operate in high radiation fields. Therefore, a small 10x10x5 mm3 CZT detector is placed inside the center of a well-shielded 3" in diameter by 3" long Nal detector. So far we have been able to successfully reduce the Compton background by a factor of 5.4 for a 137Cs spectrum. This reduction of background will definitely enhance the quality of the gamma-ray spectrum in the information-rich energy range below 1 MeV, which consequently increases the detection sensitivity. In this work, we will discuss the performance of this detection system as well as its applications.
Date: October 1, 2004
Creator: Aryaeinejd, R.; Hartwell, J. K. & Scates, Wade W.
System: The UNT Digital Library
HADES, A Code for Simulating a Variety of Radiographic Techniques (open access)

HADES, A Code for Simulating a Variety of Radiographic Techniques

It is often useful to simulate radiographic images in order to optimize imaging trade-offs and to test tomographic techniques. HADES is a code that simulates radiography using ray tracing techniques. Although originally developed to simulate X-Ray transmission radiography, HADES has grown to simulate neutron radiography over a wide range of energy, proton radiography in the 1 MeV to 100 GeV range, and recently phase contrast radiography using X-Rays in the keV energy range. HADES can simulate parallel-ray or cone-beam radiography through a variety of mesh types, as well as through collections of geometric objects. HADES was originally developed for nondestructive evaluation (NDE) applications, but could be a useful tool for simulation of portal imaging, proton therapy imaging, and synchrotron studies of tissue. In this paper we describe HADES' current capabilities and discuss plans for a major revision of the code.
Date: October 28, 2004
Creator: Aufderheide, Maurice B.; Henderson, Gary; Schach von Wittenau, Alexis E.; Slone, Dale M.; Barty, Anton & Martz, Harry E., Jr.
System: The UNT Digital Library
SPIN DEPENDENCE IN ELASTIC SCATTERING IN THE CNI REGION. (open access)

SPIN DEPENDENCE IN ELASTIC SCATTERING IN THE CNI REGION.

The interference of the electromagnetic spin-flip amplitude with a hadronic spin-nonflip amplitude in the elastic scattering of hadrons leads to significant spin dependencies at very low 4-momentum transfer t (0.001 < |t| < 0.01 (GeV/c){sup 2}). This kinematical region is known as the Coulomb Nuclear Interference (CNI) region. First results on spin effects in polarized proton-proton elastic scattering in the CNI region at 100 GeV from the 2004 polarized proton run at RHIC are presented. Preliminary results on A{sub N} in the elastic scattering of polarized protons off a carbon target over a wide energy range from 4 GeV to 100 GeV from AGS and RHIC are presented as well. These results allow us to further investigate the spin dependence in elastic scattering and the mechanisms at work.
Date: October 10, 2004
Creator: BRAVAR, A.; MAKDISI, Y. & AL., ET
System: The UNT Digital Library
Measurement of 107Ag(alpha,gamma)111 In Cross Sections (open access)

Measurement of 107Ag(alpha,gamma)111 In Cross Sections

Cross sections have been measured for the {sup 107}Ag({alpha},{gamma}){sup 111}In reaction at several a-particle energies between 7.8 MeV and 11.9 MeV. This reaction is of interest because it can provide a check on calculations of low-energy ({alpha},{gamma}) cross sections required for stellar nucleosynthesis predictions. Stacks of natural Ag foils of 1 mm thickness and 99.97% purity were bombarded with {sup 4}He{sup +} beams. Following irradiation, the yields of the 171-keV and 245-keV photons produced in the 2.805 day electron-capture decay of the {sup 111}In product nucleus were measured off-line. The Ag foils were interleaved with 99.6% purity, 6 {micro}m thick natural Ti foils so that known cross sections for the {sup 48}Ti({alpha},n) reaction could be used to check the accuracy of the beam current integration. For any given beam energy, beam energy degradation in the foils resulted in lower effective bombarding energies for successive foils in the stack, enabling measurements to be made for several energies per irradiation. The measured cross sections are compared with published statistical-model calculations.
Date: October 7, 2004
Creator: Baglin, C M; Norman, E B; Larimer, R & Rech, G A
System: The UNT Digital Library
Crystal Level Continuum Modeling of Phase Transformations: The (alpha) <--> (epsilon) Transformation in Iron (open access)

Crystal Level Continuum Modeling of Phase Transformations: The (alpha) <--> (epsilon) Transformation in Iron

We present a crystal level model for thermo-mechanical deformation with phase transformation capabilities. The model is formulated to allow for large pressures (on the order of the elastic moduli) and makes use of a multiplicative decomposition of the deformation gradient. Elastic and thermal lattice distortions are combined into a single lattice stretch to allow the model to be used in conjunction with general equation of state relationships. Phase transformations change the mass fractions of the material constituents. The driving force for phase transformations includes terms arising from mechanical work, from the temperature dependent chemical free energy change on transformation, and from interaction energy among the constituents. Deformation results from both these phase transformations and elasto-viscoplastic deformation of the constituents themselves. Simulation results are given for the {alpha} to {epsilon} phase transformation in iron. Results include simulations of shock induced transformation in single crystals and of compression of polycrystals. Results are compared to available experimental data.
Date: October 18, 2004
Creator: Barton, N R; Benson, D J; Becker, R; Bykov, Y & Caplan, M
System: The UNT Digital Library
APS Neutrino Study: Report of the neutrino astrophysics and cosmology working group (open access)

APS Neutrino Study: Report of the neutrino astrophysics and cosmology working group

In 2002, Ray Davis and Masatoshi Koshiba were awarded the Nobel Prize in Physics 'for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos'. However, while astronomy has undergone a revolution in understanding by synthesizing data taken at many wavelengths, the universe has only barely been glimpsed in neutrinos, just the Sun and the nearby SN 1987A. An entire universe awaits, and since neutrinos can probe astrophysical objects at densities, energies, and distances that are otherwise inaccessible, the results are expected to be particularly exciting. Similarly, the revolution in quantitative cosmology has heightened the need for very precise tests that depend on the effects of neutrinos, and prominent among them is the search for the effects of neutrino mass, since neutrinos are a small but known component of the dark matter. In this report, we highlight some of the key opportunities for progress in neutrino astrophysics and cosmology, and the implications for other areas of physics.
Date: October 2004
Creator: Barwick, Steve W.; Beacom, John F.; Cianciolo, Vince; Dodelson, Scott; Feng, Jonathan L.; Fuller, George M. et al.
System: The UNT Digital Library
Remarks on a model of thermal transport in nanofluids (open access)

Remarks on a model of thermal transport in nanofluids

None
Date: October 12, 2004
Creator: Bastea, S
System: The UNT Digital Library
Study of possible scintillation mechanism damage in PbWO(4) crystals after pion irradiation (open access)

Study of possible scintillation mechanism damage in PbWO(4) crystals after pion irradiation

None
Date: October 1, 2004
Creator: Batarin, V. A.; Butler, J.; Chen, T. Y.; Davidenko, A. M.; Derevschikov, A. A.; Goncharenko, Y. M. et al.
System: The UNT Digital Library
Study of Dark Matter inspired cMSSM scenarios at a TeV-class Linear Collider (open access)

Study of Dark Matter inspired cMSSM scenarios at a TeV-class Linear Collider

The accuracy in the measurement of the masses of sleptons and heavy Higgs bosons in cMSSM scenarios, compatible with the WMAP result on cold dark matter, has been re-analysed in view of the requirements for predicting this density to a few percent level from SUSY measurements at the linear collider.
Date: October 8, 2004
Creator: Battaglia, Marco
System: The UNT Digital Library
Towards pair production near threshold with unstable particle effective theory (open access)

Towards pair production near threshold with unstable particle effective theory

We illustrate the use of effective theory techniques to describe processes involving unstable particles close to resonance. First, we present the main ideas in the context of a scalar resonance in an Abelian gauge-Yukawa model. We then outline the necessary modifications to describe W-pair production close to threshold in electron-positron collisions.
Date: October 1, 2004
Creator: Beneke, M.; Kauer, N.; Signer, A. & Zanderighi, G.
System: The UNT Digital Library
Recent Results From Optimization Studies of Linear Non-Scaling Ffags for Muon Acceleration. (open access)

Recent Results From Optimization Studies of Linear Non-Scaling Ffags for Muon Acceleration.

Because of the highly repetitive nature and simple cell structure of FFAG lattices, it is possible to automatically design these lattices. In designing an FFAG lattice, one will try to meet certain constraints and then minimize some cost function by varying any remaining free parameters. I will first review previously published work on optimized FFAG design. Then I will describe recent advances in the understanding of linear non-scaling FFAG design that have come from these optimization techniques. I will describe how the lattice designs depend on some input parameters to the design. Finally, I will present a set of FFAG lattices that are optimized for muon acceleration using these techniques.
Date: October 13, 2004
Creator: Berg, J. S.
System: The UNT Digital Library