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Effects of Temporal Wind Patterns on the Value of Wind-Generated Electricity in California and the Northwest (open access)

Effects of Temporal Wind Patterns on the Value of Wind-Generated Electricity in California and the Northwest

Wind power production is variable, but also has diurnal and seasonal patterns. These patterns differ between sites, potentially making electric power from some wind sites more valuable for meeting customer loads or selling in wholesale power markets. This paper investigates whether the timing of wind significantly affects the value of electricity from sites in California and the Northwestern United States. We use both measured and modeled wind data and estimate the time-varying value of wind power with both financial and load-based metrics. We find that the potential difference in wholesale market value between better-correlated and poorly correlated wind sites is modest, on the order of 5-10 percent. A load-based metric, power production during the top 10 percent of peak load hours, varies more strongly between sites, suggesting that the capacity value of different wind projects could vary by as much as 50 percent based on the timing of wind alone.
Date: May 1, 2008
Creator: Wiser, Ryan H; Wiser, Ryan H & Fripp, Matthias
System: The UNT Digital Library
Measurement of Flow Phenomena in a VHTR Lower Plenum Model (open access)

Measurement of Flow Phenomena in a VHTR Lower Plenum Model

Mean velocity and turbulence data that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor are presented as a follow-up to summaries presented at the 2006 Annual Meeting and the 2006 Winter Meeting. The experiments were designed to develop benchmark databases to support the first Standard Problem endorsed by the Generation IV International Forum to validate the heat transfer and fluid flow software that will be used to study the behavior of the VHTR system.
Date: June 1, 2007
Creator: Jr., Hugh M. McIlroy; McEligot, Donald M. & Pink, Robert J.
System: The UNT Digital Library
Update on Mechanical Analysis of Monolithic Fuel Plates (open access)

Update on Mechanical Analysis of Monolithic Fuel Plates

Results on the relative bond strength of the fuel-clad interface in monolithic fuel plates have been presented at previous RRFM conferences. An understanding of mechanical properties of the fuel, cladding, and fuel / cladding interface has been identified as an important area of investigation and quantification for qualification of monolithic fuel forms. Significant progress has been made in the area of mechanical analysis of the monolithic fuel plates, including mechanical property determination of fuel foils, cladding processed by both hot isostatic pressing and friction bonding, and the fuel-clad composite. In addition, mechanical analysis of fabrication induced residual stress has been initiated, along with a study to address how such stress can be relieved prior to irradiation. Results of destructive examinations and mechanical tests are presented along with analysis and supporting conclusions. A brief discussion of alternative non-destructive evaluation techniques to quantify not only bond quality, but also bond integrity and strength, will also be provided. These are all necessary steps to link out-of-pile observations as a function of fabrication with in-pile behaviours.
Date: March 1, 2008
Creator: Burkes, D. E.; Rice, F. J.; Jue, J.-F. & Hallinan, N. P.
System: The UNT Digital Library
Making Sustainable Decisions Using the KONVERGENCE Framework (open access)

Making Sustainable Decisions Using the KONVERGENCE Framework

Hundreds of contaminated facilities and sites must be cleaned up. “Cleanup” includes decommissioning, environmental restoration, and waste management. Cleanup can be complex, expensive, risky, and time-consuming. Decisions are often controversial, can stall or be blocked, and are sometimes re-done - some before implementation, some decades later. Making and keeping decisions with long time horizons involves special difficulties and requires new approaches, including: • New ways (mental model) to analyze and visualize the problem, • Awareness of the option to shift strategy or reframe from a single decision to an adaptable network of decisions, and • Improved tactical processes that account for several challenges. These include the following: • Stakeholder values are a more fundamental basis for decision making and keeping than “meeting regulations.” • Late-entry players and future generations will question decisions. • People may resist making “irreversible” decisions. • People need “compelling reasons” to take action in the face of uncertainties. Our project goal is to make cleanup decisions easier to make, implement, keep, and sustain. By sustainability, we mean decisions that work better over the entire time-period—from when a decision is made, through implementation, to its end point. That is, alternatives that can be kept “as is” or …
Date: February 1, 2003
Creator: Piet, Steven James; Gibson, Patrick Lavern; Joe, Jeffrey Clark; Kerr, Thomas A; Nitschke, Robert Leon & Dakins, Maxine Ellen
System: The UNT Digital Library
Decays of B_s Mesons and b Baryons: A Review of Recent First Observations and Branching Fractions (open access)

Decays of B_s Mesons and b Baryons: A Review of Recent First Observations and Branching Fractions

Recent rate measurements of B{sub s}{sup 0} mesons and {Lambda}{sub b}{sup 0} baryons produced in {radical}s = 1.96 TeV proton-antiproton and {Upsilon}(5S) electron-positron collisions are reviewed, including the first observations of six new decay modes: B{sub s}{sup 0} {yields} D{sub s}{sup +} K{sup -} (CDF), B{sub s}{sup 0} {yields} D{sub s}{sup -} D{sub s}{sup +} (CDF), B{sub s}{sup 0} {yields} D{sub s1}{sup -}(2536){mu}{sup +} {nu}{sub {mu}} X (DZero), B{sub s}{sup 0} {yields} {phi}{gamma} (Belle)< {Lambda}{sub b}{sup 0} {yields} p{pi}{sup -} (CDF), and {Lambda}{sub b}{sup 0} {yields} pK{sup -} (CDF). Also examined are branching-fraction measurements or limits for the B{sub s}{sup 0} {yields} D{sub s}{sup (*)} D{sub s}{sup (*)} modes (Belle, CDF, and DZero), the B{sub s}{sup 0} {yields} {gamma}{gamma} radiative penguin decay (Belle), and three two-body charmless B{sub s}{sup 0} meson decay channels (CDF). Implications for the phenomenology of electroweak and QCD physics, as well as searches for physics beyond the Standard Model, are identified where applicable.
Date: June 1, 2008
Creator: Warburton, Andreas
System: The UNT Digital Library
Syntheses, Structure, Magnetism, and Optical Properties of Lutetium-based Interlanthanide Selenides (open access)

Syntheses, Structure, Magnetism, and Optical Properties of Lutetium-based Interlanthanide Selenides

Ln{sub 3}LuSe{sub 6} (Ln = La, Ce), {beta}-LnLuSe{sub 3} (Ln = Pr, Nd), and Ln{sub x}Lu{sub 4-x}Se{sub 6} (Ln = Sm, Gd; x = 1.82, 1.87) have been synthesized using a Sb{sub 2}Se{sub 3} flux at 1000 C. Ln{sub 3}LuSe{sub 6} (Ln = La, Ce) adopt the U{sub 3}ScS{sub 6}-type three-dimensional structure, which is constructed from two-dimensional {infinity}{sup 2} [Ln{sub 3}Se{sub 6}]{sup 3-} slabs with the gaps between these slabs filled by octahedrally coordinated Lu{sup 3+} ions. The series of {beta}-LnLuSe{sub 3} (Ln = Pr, Nd) are isotypic with UFeS{sub 3}. Their structures include layers formed from LuSe6 octahedra that are separated by eight-coordinate larger Ln{sup 3+} ions in bicapped trigonal prismatic environments. Sm{sub 1.82}Lu{sub 2.18}Se{sub 6} and Gd{sub 1.87}Lu{sub 2.13}Se{sub 6} crystallize in the disordered F-Ln{sub 2}S{sub 3} type structure with the eight-coordinate bicapped trigonal prismatic Ln(1) ions residing in the one-dimensional channels formed by three different double chains via edge and corner sharing. These double chains are constructed from Ln(2)Se{sub 7} monocapped trigonal prisms, Ln(3)Se{sub 6} octahedra, and Ln(4)S{sub 6} octahedra, respectively. The magnetic susceptibilities of {beta}-PrLuSe{sub 3} and {beta}-NdLuSe{sub 3} follow the Curie-Weiss law. Sm{sub 1.82}Lu{sub 2.18}Se{sub 6} shows van Vleck paramagnetism. Magnetic measurements show that Gd{sub …
Date: October 1, 2007
Creator: Booth, Corwin H; Jin, Geng Bang; Choi, Eun Sang; Guertin, Robert P.; Brooks, James S.; Booth, Corwin H. et al.
System: The UNT Digital Library
Optimization of the Helical Orbits in the Tevatron (open access)

Optimization of the Helical Orbits in the Tevatron

To avoid multiple head-on collisions the proton and antiproton beams in the Tevatron move along separate helical orbits created by 7 horizontal and 8 vertical electrostatic separators. Still the residual long-range beam-beam interactions can adversely affect particle motion at all stages from injection to collision. With increased intensity of the beams it became necessary to modify the orbits in order to mitigate the beam-beam effect on both antiprotons and protons. This report summarizes the work done on optimization of the Tevatron helical orbits, outlines the applied criteria and presents the achieved results.
Date: June 1, 2007
Creator: Alexahin, Y.
System: The UNT Digital Library
An array of low-background 3He proportional counters for theSudbury Neutrino Observatory (open access)

An array of low-background 3He proportional counters for theSudbury Neutrino Observatory

An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neutrons liberated by the neutrino-deuteronneutral current reaction in the D2O, and four strings lled with a mixtureof 4He and CF4 gas for background measurements. The proportional counterdiameter is 5 cm. The total deployed array length was 398 m. The SNO NCDarray is the lowest-radioactivity large array of proportional countersever produced. This article describes the design, construction,deployment, and characterization of the NCD array, discusses theelectronics and data acquisition system, and considers event signaturesand backgrounds.
Date: February 1, 2007
Creator: Amsbaugh, J. F.; Anaya, J. M.; Banar, J.; Bowles, T. J.; Browne, M. C.; Bullard, T. V. et al.
System: The UNT Digital Library
NC pi0 Production in the MiniBooNE Antineutrino Data (open access)

NC pi0 Production in the MiniBooNE Antineutrino Data

None
Date: January 1, 2008
Creator: Nguyen, V.T.
System: The UNT Digital Library
Tevatron results on the discovery of sigma^(*)_b, b_s oscillations and the measurement of delta m_s, the lifetime difference delta gamma_s and the cp-violating phase phi (open access)

Tevatron results on the discovery of sigma^(*)_b, b_s oscillations and the measurement of delta m_s, the lifetime difference delta gamma_s and the cp-violating phase phi

The author discusses results from the Tevatron experiments on mixing and CP-violation in B{sub s} mesons, including the observation of B{sub s} oscillations and the first precision measurement of the mixing frequency, as well as a measurement of the lifetime difference {Delta}{Lambda}{sub s} and the first measurement of the CP-violating phase {delta}{sub s}. The author also briefly reports on the observation of four new bottom baryons at CDF.
Date: October 1, 2007
Creator: Heijboer, Aart
System: The UNT Digital Library
Demonstration of Femtosecond-Phase Stabilization in 2 km OpticalFiber (open access)

Demonstration of Femtosecond-Phase Stabilization in 2 km OpticalFiber

Long-term phase drifts of less than a femtosecond per hour have been demonstrated in a 2 km length of single-mode optical fiber, stabilized interferometrically at 1530 nm. Recent improvements include a wide-band phase detector that reduces the possibility of fringe jumping due to fast external perturbations of the fiber and locking of the master CW laser wavelength to an atomic absorption line. Mode-locked lasers may be synchronized using two wavelengths of the comb, multiplexed over one fiber, each wavelength individually interferometrically stabilized.
Date: June 1, 2007
Creator: Staples, J. W.; Wilcox, R. & Byrd, J. M.
System: The UNT Digital Library
Impedance Noise Identification for State-of-Health Prognostics (open access)

Impedance Noise Identification for State-of-Health Prognostics

Impedance Noise Identification is an in-situ method of measuring battery impedance as a function of frequency using a random small signal noise excitation source. Through a series of auto- and cross-correlations and Fast Fourier Transforms, the battery complex impedance as a function of frequency can be determined. The results are similar to those measured under a lab-scale electrochemical impedance spectroscopy measurement. The lab-scale measurements have been shown to correlate well with resistance and power data that are typically used to ascertain the remaining life of a battery. To this end, the Impedance Noise Identification system is designed to acquire the same type of data as an on-board tool. A prototype system is now under development, and results are being compared to standardized measurement techniques such as electrochemical impedance spectroscopy. A brief description of the Impedance Noise Identification hardware system and representative test results are presented.
Date: July 1, 2008
Creator: Christophersen, Jon P.; Motloch, Chester G.; Morrison, John L.; Donnellan, Ian B. & Morrison, William H.
System: The UNT Digital Library
A short model excitation of an asymmetric force free superconducting transmission line magnet (open access)

A short model excitation of an asymmetric force free superconducting transmission line magnet

A short model of asymmetric force free magnet with single beam aperture was tested at Fermilab together with the excitation test of VLHC transmission line magnet. The design concept of asymmetric force free superconducting magnet was verified by the test. The testing reached up to 104 kA current and no indication of force imbalance was observed. Since the model magnet length was only 10cm, A 0.75m model was constructed and tested at KEK with low current to ensure the validity of the design. The cool down and the excitation at KEK were also successful finding very small thermal contraction of the conductor and reasonable field homogeneity.
Date: September 1, 2005
Creator: Wake, M.; Sato, H.; Carcagno, R.; Foster, W.; Hays, S.; Kashikhin, V. et al.
System: The UNT Digital Library
Measurement of correlated b-bbar production in p-pbar collisions at s**(1/2) = 1960 GeV (open access)

Measurement of correlated b-bbar production in p-pbar collisions at s**(1/2) = 1960 GeV

We present a measurement of the correlated b{bar b} production cross section. The data used in this analysis were taken with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider, and correspond to an integrated luminosity of 742 pb{sup -1}. We utilize muon pairs with invariant mass 5 {le} m{sub {mu}{mu}} {le} 80 GeV/c{sup 2} produced by b{bar b} double semileptonic decays. For muons with p{sub T} {ge} 3 GeV/c and |{eta}| {le} 0.7, that are produced by b and {bar b} quarks with p{sub T} {ge} 2 GeV/c and |y| {le} 1.3, we measure {sigma}{sub b{yields}{mu},{bar b}{yields}{mu}} = 1549 {+-} 133 pb. We compare this result with theoretical predictions and previous measurements. We also report the measurement of {sigma}{sub c{yields}{mu},{bar c}{yields}{mu}}, a by-product of the study of the background to b{bar b} production.
Date: November 1, 2007
Creator: Aaltonen, T.; Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M. G. et al.
System: The UNT Digital Library
Transatlantic transport of Fermilab 3.9 GHz cryomodule for TTF/FLASH to DESY (open access)

Transatlantic transport of Fermilab 3.9 GHz cryomodule for TTF/FLASH to DESY

In an exchange of technology agreement, Fermilab built and will deliver a 3.9 GHz (3rd harmonic) cryomodule to DESY to be installed in the TTF/FLASH beamline. This cryomodule delivery will involve a combination of flatbed air ride truck and commercial aircraft transport to Hamburg Germany. A description of the isolation and damping systems that maintain alignment during transport and protect fragile components is provided. Initially, transport and corresponding alignment stability studies were performed in order to assess the risk associated with transatlantic travel of a fully assembled cryomodule. Shock loads were applied to the cryomodule by using a coldmass mockup to prevent subjecting actual critical components (such as the cavities and input couplers) to excessive forces. Accumulative and peak shock loads were applied through over-the-road testing and using a pendulum hammer apparatus, respectively. Finite Element Analysis (FEA) studies were implemented to define location of instrumentation for transport studies and provide modal frequencies and shapes. Shock and vibration measurement results of transport studies and stabilization techniques are discussed.
Date: June 1, 2008
Creator: McGee, M. W.; Vocean, V.; Grimm, C. & Schappert, W.
System: The UNT Digital Library
Long Pulse High Performance Plasma Scenario Development for the National Spherical Torus Experiment (open access)

Long Pulse High Performance Plasma Scenario Development for the National Spherical Torus Experiment

The National Spherical Torus Experiment [Ono et al., Nucl. Fusion, 44, 452 (2004)] is targeting long pulse high performance, noninductive sustained operations at low aspect ratio, and the demonstration of nonsolenoidal startup and current rampup. The modeling of these plasmas provides a framework for experimental planning and identifies the tools to access these regimes. Simulations based on neutral beam injection (NBI)-heated plasmas are made to understand the impact of various modifications and identify the requirements for (1) high elongation and triangularity, (2) density control to optimize the current drive, (3) plasma rotation and/or feedback stabilization to operate above the no-wall limit, and (4) electron Bernstein waves (EBW) for off-axis heating/current drive (H/CD). Integrated scenarios are constructed to provide the transport evolution and H/CD source modeling, supported by rf and stability analyses. Important factors include the energy confinement, Zeff, early heating/H mode, broadening of the NBI-driven current profile, and maintaining q(0) and qmin>1.0. Simulations show that noninductive sustained plasmas can be reached at IP=800 kA, BT=0.5 T, 2.5, N5, 15%, fNI=92%, and q(0)>1.0 with NBI H/CD, density control, and similar global energy confinement to experiments. The noninductive sustained high plasmas can be reached at IP=1.0 MA, BT=0.35 T, 2.5, N9, 43%, …
Date: January 1, 2006
Creator: Kessel, C.E.; Bell, R.E.; Bell, M.G.; Gates, D.A. & Harvey, R.W.
System: The UNT Digital Library
Kinetics of the water adsorption driven structural transformationof ZnS nanoparticles (open access)

Kinetics of the water adsorption driven structural transformationof ZnS nanoparticles

Nanoparticles of certain materials can respond structurally to changes in their surface environments. We have previously shown that methanol, water adsorption, and aggregation-disaggregation can change the structure of 3 nm diameter zinc sulfide (ZnS). However, in prior observations of water-driven structure change, aggregation may also have taken place. Therefore, we investigated the structural consequences of water adsorption alone on anhydrous nanoparticles that were dried to minimize changes in aggregation. Using simultaneously collected small- and wide-angle x-ray scattering (SAXS/WAXS) data, we show that water vapor adsorption alone drives a structural transformation in ZnS nanoparticles in the temperature range 22-40 C. The transition kinetics are strongly temperature dependent, with an activation energy of 58.1 {+-} 9.8 kJ/mol, consistent with atom displacement rather than bond breaking. At 50 C, aggregate restructuring occurred, increasing the transition kinetics beyond the rate expected for water adsorption alone. The observation of isosbestic points in the WAXS data suggests that the particles do not transform continuously between the initial and final structural state but rather undergo an abrupt change from a less ordered to a more ordered state.
Date: August 1, 2007
Creator: Goodell, C. M.; Gilbert, B.; Weigand, S. J. & Banfield, J. F.
System: The UNT Digital Library
Carbon Dioxide Selective Supported Ionic Liquid Membranes: The Effect of Contaminants (open access)

Carbon Dioxide Selective Supported Ionic Liquid Membranes: The Effect of Contaminants

The integrated gasification combined cycle (IGCC) is widely viewed as a promising technology for the large scale production of energy in a carbon constrained world. These cycles, which include gasification, contaminant removal, water-gas shift, CO2 capture and compression, and combustion of the reduced-carbon fuel gas in a turbine, often have significant efficiency advantages over conventional combustion technologies. A CO2 selective membrane capable of maintaining performance at conditions approaching those of low temperature water-gas shift (260oC) could facilitate the production of carbon-neutral energy by simultaneously driving the shift reaction to completion and concentrating CO2 for sequestration. Supported ionic liquid membranes (SILMs) have been previously evaluated for this application and determined to be physically and chemically stable to temperatures in excess of 300oC. These membranes were based on ionic liquids which interacted physically with CO2 and diminished considerably in selectivity at higher temperatures. To alleviate this problem, the original ionic liquids were replaced with ionic liquids able to form chemical complexes with CO2. These complexing ionic liquid membranes have a local maximum in selectivity which is observed at increasing temperatures for more stable complexes. Efforts are currently underway to develop ionic liquids with selectivity maxima at temperatures greater than 75oC, the best …
Date: April 1, 2008
Creator: Luebke, D. R.; Ilconich, J. B.; Myers, C. R. & Pennline, H. W.
System: The UNT Digital Library
Some Interesting Min-Bias Distributions for Early LHC Runs (open access)

Some Interesting Min-Bias Distributions for Early LHC Runs

A few observable distributions in min-bias (inelastic, non-diffractive) events which could be well constrained with early LHC data are presented, with some comments on their significance for placing constraints on theoretical models. The effects of fiducial cuts (p{perpendicular} > 0.5 GeV, |{eta}| < 2.5) and extrapolation from the Tevatron are illustrated.
Date: December 1, 2007
Creator: Skands, P. Z.
System: The UNT Digital Library
Comparison groups on bills: Automated, personalized energy information (open access)

Comparison groups on bills: Automated, personalized energy information

A program called ``Innovative Billing?? has been developed to provide individualized energy information for a mass audience?the entireresidential customer base of an electric or gas utility. Customers receive a graph on the bill that compares that customer?s consumption with othersimilar customers for the same month. The program aims to stimulate customers to make ef?ciency improvements. To group as many as severalmillion customers into small ``comparison groups??, an automated method must be developed drawing solely from the data available to the utility.This paper develops and applies methods to compare the quality of resulting comparison groups.A data base of 114,000 customers from a utility billing system was used to evaluate Innovative Billing comparison groups, comparing fouralternative criteria: house characteristics (?oor area, housing type, and heating fuel); street; meter read route; billing cycle. Also, customers wereinterviewed to see what forms of comparison graphs made most sense and led to fewest errors of interpretation. We ?nd that good qualitycomparison groups result from using street name, meter book, or multiple house characteristics. Other criteria we tested, such as entire cycle, entiremeter book, or single house characteristics such as ?oor area, resulted in poor quality comparison groups. This analysis provides a basis forchoosing comparison groups based …
Date: July 1, 2006
Creator: Iyer, Maithili; Kempton, Willett & Payne, Christopher
System: The UNT Digital Library
Progress In High Temperature Electrolysis At The Idaho National Laboratory (open access)

Progress In High Temperature Electrolysis At The Idaho National Laboratory

The United States is considering the development of a domestic hydrogen-based energy economy. Hydrogen is of particular interest as a secondary energy carrier because it has the potential to be storable, transportable, environmentally benign, and useful in many chemical processes. Obviously, before a hydrogen economy can be implemented, an efficient and environmentally friendly means for large scale hydrogen production must be identified, proven, and developed. Hydrogen is now produced primarily via steam reforming of methane. However, from a long-term perspective, methane reforming is not a viable process for large-scale production of hydrogen since such fossil fuel conversion processes consume non-renewable resources and emit greenhouse gases. The U. S. National Research Council has recommended the use of water-splitting technologies to produce hydrogen using energy derived from a nuclear reactor. For the past several years, the Idaho National Laboratory has been actively studying the use of solid oxide fuel cells in conjunction with nuclear power for large-scale, high-temperature, electrolytic hydrogen production.
Date: October 1, 2007
Creator: Stoots, Carl M.; E.O'Brien, James; Herring, J. Steve & Hartvigsen, Joseph
System: The UNT Digital Library
Measurement of the Top Quark Mass using Quantities with Minimal Dependence on the Jet Energy Scale (open access)

Measurement of the Top Quark Mass using Quantities with Minimal Dependence on the Jet Energy Scale

None
Date: August 1, 2008
Creator: Garberson, F.; Incandela, J.; Koay, S.; Rossin, R.; /UC, Santa Barbara; Hill, C. et al.
System: The UNT Digital Library
Calculation of Reactive-evaporation Rates of Chromia (open access)

Calculation of Reactive-evaporation Rates of Chromia

A methodology is developed to calculate Cr-evaporation rates from Cr2O3 with a flat planar geometry. Variables include temperature, total pressure, gas velocity, and gas composition. The methodology was applied to solid-oxide, fuel cell conditions for metallic interconnects and to advanced-steam turbines conditions. The high velocities and pressures of the advanced steam turbine led to evaporation predictions as high as 5.18 9 10-8 kg/m2/s of CrO2(OH)2(g) at 760 °C and 34.5 MPa. This is equivalent to 0.080 mm per year of solid Cr loss. Chromium evaporation is expected to be an important oxidation mechanism with the types of nickel-base alloys proposed for use above 650 °C in advanced-steam boilers and turbines. It is shown that laboratory experiments, with much lower steam velocities and usually much lower total pressure than found in advanced steam turbines, would best reproduce chromium-evaporation behavior with atmospheres that approach either O2 + H2O or air + H2O with 57% H2O.
Date: April 1, 2008
Creator: Holcomb, G. R.
System: The UNT Digital Library
Search for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II Using Photon Timing (open access)

Search for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II Using Photon Timing

The authors present the results of the first hadron collider search for heavy, long-lived neutralinos that decay via {tilde {chi}}{sub 1}{sup 0} {yields} {gamma}{tilde G} in gauge-mediated supersymmetry breaking models. Using an integrated luminosity of 570 {+-} 34 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, they select {gamma}+jet+missing transverse energy candidate events based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed on the CDF II detector. They find 2 events, consistent with the background estimate of 1.3 {+-} 0.7 events. While the search strategy does not rely on model-specific dynamics, they set cross section limits and place the world-best 95% C.L. lower limit on the {tilde {chi}}{sub 1}{sup 0} mass of 101 GeV/c{sup 2} at {tau}{sub {tilde {chi}}{sub 1}{sup 0}} = 5 ns.
Date: April 1, 2008
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Alvarez Gonzalez, B.; Amerio, S. et al.
System: The UNT Digital Library