Neutron Capture and Transmission Measurements and Resonance Parameter Analysis of Niobium (open access)

Neutron Capture and Transmission Measurements and Resonance Parameter Analysis of Niobium

None
Date: July 1, 2005
Creator: Drindak, NJ; Burke, JA; Leinweber, G; Helm, JA; Hoole, JG; Block, RC et al.
System: The UNT Digital Library
Risked Based Inspection (External Conference MaterialsRBI) of Steam Systems (open access)

Risked Based Inspection (External Conference MaterialsRBI) of Steam Systems

This paper describes the implementation of a risk-based inspection program for process and utility steam lines in a large chemical process facility. The paper addresses first the development of an RBI matrix, the likelihood attributes, the consequence scores, and the overall risk in terms of personnel safety and costs. Systems are plotted on the RBI matrix to develop inspection priorities. The RBI ranking is followed by inspection planning, acceptance criteria, and wall thickness inspection techniques, including UT, pulsed eddy current and digital radiography.
Date: July 1, 2005
Creator: GEORGE, ANTAKI
System: The UNT Digital Library
Positron Annihilation in the Bipositronium Ps2 (open access)

Positron Annihilation in the Bipositronium Ps2

The electron-positron-pair annihilation in the bipositronium PS2 is considered. In particular, the two-, three-, one- and zero-photon annihilation rates are determined to high accuracy. The corresponding analytical expressions are also presented. Also, a large number of bound state properties have been determined for this system.
Date: July 1, 2005
Creator: Bailey, David H. & Frolov, Alexei M.
System: The UNT Digital Library
Identification of Severe Multiple Contingencies in Electric PowerNetworks (open access)

Identification of Severe Multiple Contingencies in Electric PowerNetworks

In this paper we propose a two-stage screening and analysis process for identifying multiple contingencies that may result in very severe disturbances and blackouts. In a screening stage we form an optimization problem to find the minimum change in the network to move the power flow feasibility boundary to the present operating point and that will cause the system to separate with a user-specified power imbalance. The lines identified by the optimization program are used in a subsequent analysis stage to find combinations that may lead to a blackout. This approach is applied to a 30-bus system with encouraging results.
Date: July 1, 2005
Creator: Donde, Vaibhav; Lopez, Vanessa; Lesieutre, Bernard; Pinar, Ali; Yang,Chao & Meza, Juan
System: The UNT Digital Library
Rationale for Measuring Duct Leakage Flows in Large Commercial Buildings (open access)

Rationale for Measuring Duct Leakage Flows in Large Commercial Buildings

Industry-wide methods of assessing duct leakage are based on duct pressurization tests, and focus on ''high pressure'' ducts. Even though ''low pressure'' ducts can be a large fraction of the system and tend to be leaky, few guidelines or construction specifications require testing these ducts. We report here on the measured leakage flows from ten large commercial duct systems at operating conditions: three had low leakage (less than 5% of duct inlet flow), and seven had substantial leakage (9 to 26%). By comparing these flows with leakage flows estimated using the industry method, we show that the latter method by itself is not a reliable indicator of whole-system leakage flow, and that leakage flows need to be measured.
Date: July 1, 2005
Creator: Wray, Craig P.; Diamond, Richard C. & Sherman, Max H.
System: The UNT Digital Library
Durability Testing of Fluidized Bed Steam Reforming Products (open access)

Durability Testing of Fluidized Bed Steam Reforming Products

Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of radioactive wastes but especially aqueous high sodium wastes at the Hanford site, at the Idaho National Laboratory (INL), and at the Savannah River Site (SRS). The FBSR technology converts organic compounds to CO{sub 2} and H{sub 2}O, converts nitrate/nitrite species to N{sub 2}, and produces a solid residue through reactions with superheated steam, the fluidizing media. If clay is added during processing a ''mineralized'' granular waste form can be produced. The mineral components of the waste form are primarily Na-Al-Si (NAS) feldspathoid minerals with cage-like and ring structures and iron bearing spinel minerals. The cage and ring structured minerals atomically bond radionuclides like Tc{sup 99} and Cs{sup 137} and anions such as SO{sub 4}, I, F, and Cl. The spinel minerals appear to stabilize Resource Conservation and Recovery Act (RCRA) hazardous species such as Cr and Ni. Durability testing of the FBSR products was performed using ASTM C1285 (Product Consistency Test) and the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP). The FBSR mineral products (bed and fines) evaluated in this study were found to be two orders of …
Date: July 1, 2005
Creator: JANTZEN, CAROL M.; PAREIZS, JOHN M.; LORIER, TROY H. & MARRA, JAMES C.
System: The UNT Digital Library
IFESS 2005 Special Session 5 Artifical Vision (open access)

IFESS 2005 Special Session 5 Artifical Vision

A special session on visual prostheses was held during the Annual Meeting of the International Functional Electrical Stimulation Society (IFESS), in Montreal, Canada, July 5-9, 2005. IFESS is a meeting that typically attracts researchers in implantable nerve stimulators, functional electrical stimulation, and rehabilitation. All of these areas have significant overlap with the retinal prosthesis, but these areas have decades of research behind them. The special session provided a forum for researchers with vast experience in nerve stimulation to interact with leading research in retinal and cortical visual prostheses. The grant paid for the travel and conference costs of the presenters in the session. The session was chaired by James Weiland (the PI on this grant). The session co-chair was Phil Troyk, Ph.D., from the Illinois Institute of Technology. The Department of Energy was acknowledged at the start of the session as the sponsor. The following talks were delivered: Clinical Trial of a Prototype Retinal Prosthesis James Weiland, Ph.D. Doheny Eye Institute, Los Angeles, California The U.S. Department of Energy's Artificial Sight Program Elias Greenbaum, Ph.D. Oak Ridge National Laboratory, Oak Ridge, Tennessee A 16-Channel stimulator ASIC for use in an intracortical visual prosthesis Phillip R. Troyk, Ph.D. Illinois Institute of …
Date: July 1, 2005
Creator: Weiland, J. D.; Greenbaum, E.; Delbeke, J.; Troyk, P. R. & Sawan, M.
System: The UNT Digital Library
Charm and beauty production at the Tevatron (open access)

Charm and beauty production at the Tevatron

None
Date: July 1, 2005
Creator: Shears, Tara
System: The UNT Digital Library
Studies of W/Z bosons at Tevatron (open access)

Studies of W/Z bosons at Tevatron

None
Date: July 1, 2005
Creator: Leone, Sandra
System: The UNT Digital Library
Measurement of total ion current from vacuum arc plasmasources (open access)

Measurement of total ion current from vacuum arc plasmasources

The total ion current generated by a vacuum arc plasma source was measured. The discharge system investigated allowed ion collection from the arc plasma streaming through a hemispherical mesh anode with geometric transparency of 72 percent. A range of different cathode materials was investigated, and the arc current was varied over the range 50-500 A. We find that the normalized ion current (Iion/Iarc) depends on the cathode material, with values in the range from 5 percent to 19 percent and generally greater for elements of low cohesive energy. The application of a strong axial magnetic field in the cathode and arc region leads to increased normalized ion current, but only by virtue of enhanced ion charge states formed in a strong magnetic field.
Date: July 1, 2005
Creator: Oks, Efim M.; Savkin, Konstantin P.; Yushkov, Georgiu Yu.; Nikolaev, Alexey G.; Anders, A. & Brown, Ian G.
System: The UNT Digital Library
Ventilation and Work Performance in Office Work (open access)

Ventilation and Work Performance in Office Work

Outdoor air ventilation rates vary considerably between and within buildings. The purpose of this study was to evaluate the potential work performance benefits of increased ventilation. They analyzed the literature relating work performance with ventilation rate and employed statistical analyses with weighting factors to combine the results of different studies. The studies included in the review assessed performance of various tasks in laboratory experiments and measured performance at work in real buildings. Almost all studies found increases in performance with higher ventilation rates. The studies indicated typically a 1-3% improvement in average performance per 10 L/s-person increase in outdoor air ventilation rate. The performance increase per unit increase in ventilation was bigger with ventilation rates below 20 L/s-person and almost negligible with ventilation rates over 45 L/s-person. The performance increase was statistically significant with increased ventilation rates up to 15 L/s-person with 95% CI and up to 17 L/s-person with 90% CI.
Date: July 1, 2005
Creator: Seppanen, Olli; Fisk, William J. & Lei, Q.H.
System: The UNT Digital Library
Tau identification at the Tevatron (open access)

Tau identification at the Tevatron

Methods for reconstructing and identifying the hadronic decays of tau leptons with the CDF and D0 detectors at the Fermilab Tevatron collider in Run II are described. Precision electroweak measurements of W and Z gauge boson cross sections are presented as well as results of searches for physics beyond the Standard Model with hadronically decaying tau leptons in the final state.
Date: July 1, 2005
Creator: Levy, Stephen
System: The UNT Digital Library
Results from the Cryogenic Dark Matter Search at Soudan Underground Laboratory (open access)

Results from the Cryogenic Dark Matter Search at Soudan Underground Laboratory

We present results from the Cryogenic Dark Matter Search at Soudan Underground Laboratory for two-tower arrays of detector. Twelve detectors were operated from March 25 to August 8, 2004, or 74.5 detector live days.Within expected background, no statistically significant indication of a WIMP signal was observed. Based on this null observation and combined with our previous results, we exclude a spin-averaged WIMP-nucleon interaction cross section above 1.6 x 10{sup -43} cm{sup 2} for Ge detectors, and 3 x 10{sup -42} cm{sup 2} for Si detectors, for a WIMP mass 60GeV/c{sup 2} with 90%C.L. This result constrains parameter space of minimal supersymmetric standard models (MSSM) and starts to reach the parameter space of a constrained model (CMSSM).
Date: July 1, 2005
Creator: Yoo, Jonghee
System: The UNT Digital Library
Experimental results for correlation-based wavefront sensing (open access)

Experimental results for correlation-based wavefront sensing

Correlation wave-front sensing can improve Adaptive Optics (AO) system performance in two keys areas. For point-source-based AO systems, Correlation is more accurate, more robust to changing conditions and provides lower noise than a centroiding algorithm. Experimental results from the Lick AO system and the SSHCL laser AO system confirm this. For remote imaging, Correlation enables the use of extended objects for wave-front sensing. Results from short horizontal-path experiments will show algorithm properties and requirements.
Date: July 1, 2005
Creator: Poyneer, L. A.; Palmer, D. W.; LaFortune, K. N. & Bauman, B.
System: The UNT Digital Library
Search for localized excess fluxes in Auger sky maps and prescription results (open access)

Search for localized excess fluxes in Auger sky maps and prescription results

Using the first surface detector data of the Pierre Auger Observatory, they present the results of a blind search for overdensities in the cosmic ray flux with respect to isotropic expectations. they consider two energy bands: 1 EeV {le} E {le} 5 EeV and E {ge} 5 EeV at two angular scales: 5{sup o} and 15{sup o}. They also report the results of searches for excesses in target directions already defined in a set of prescriptions presented at the ICRC in 2003. At the moment, both analyses give results that are compatible with isotropy.
Date: July 1, 2005
Creator: Revenu, Benoit & /Paris, Inst. Astrophys.
System: The UNT Digital Library
Eddy current scanning at Fermilab (open access)

Eddy current scanning at Fermilab

In the framework of SRF cavity development, Fermilab is creating the infrastructure needed for the characterization of the material used in the cavity fabrication. An important step in the characterization of ''as received'' niobium sheets is the eddy current scanning. Eddy current scanning is a non-destructive technique first adopted and further developed by DESY with the purpose of checking the cavity material for sub-surface defects and inclusions. Fermilab has received and further upgraded a commercial eddy current scanner previously used for the SNS project. The upgrading process included developing new filtering software. This scanner is now used daily to scan the niobium sheets for the Fermilab third harmonic and transverse deflecting cavities. This paper gives a status report on the scanning results obtained so far, including a discussion of the typology of signals being detected. We also report on the efforts to calibrate this scanner, a work conducted in collaboration with DESY.
Date: July 1, 2005
Creator: Boffo, C.; Bauer, P.; Foley, M.; /Fermilab; Brinkmann, A.; /DESY et al.
System: The UNT Digital Library
Di-boson physics at the Tevatron (open access)

Di-boson physics at the Tevatron

A summary is presented of recent measurements of di-boson production at the Tevatron. The results from the CDF and D0 experiments are based upon 130-320 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV. The W{gamma}, Z{gamma}, WW, and WZ production properties are compared to Standard Model predictions, and limits extracted for anomalous triple gauge couplings.
Date: July 1, 2005
Creator: Goshaw, A.T. & U., /Duke
System: The UNT Digital Library
Search for W and Z bosons in the reaction anti-p p ---> 2 jets + gamma at s**(1/2) = 1.8-TeV (open access)

Search for W and Z bosons in the reaction anti-p p ---> 2 jets + gamma at s**(1/2) = 1.8-TeV

The authors present a study of the dijet invariant mass distribution for the reaction {bar p}p {yields} 2 jets+{gamma} + X, at a center of mass energy of 1.8 TeV, using data collected by the CDF experiment. They compare the data to predictions for the production of a photon with two jets, together with the resonant processes {bar p}p {yields} W/Z + {gamma} + X, in which the W and Z bosons decay hadronically. A fit is made to the dijet invariant mass distribution combining the non-resonant background and resonant processes. They use the result to establish a limit for the inclusive production cross section of W/Z + {gamma} with hadronic decay of the W and Z bosons.
Date: July 1, 2005
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
System: The UNT Digital Library
Current and future searches for dark matter (open access)

Current and future searches for dark matter

Recent experimental data confirms that approximately one quarter of the universe consists of cold dark matter. Particle theories provide natural candidates for this dark matter in the form of either Axions or Weakly Interacting Massive Particles (WIMPs). A growing body of experiments is aimed at direct or indirect detection of particle dark matter. I summarize the current status of these experiments and offer projections of their future sensitivity.
Date: July 1, 2005
Creator: Bauer, Daniel A.
System: The UNT Digital Library
Validation of the real and simulated data of the pierre auger fluorescence telescopes (open access)

Validation of the real and simulated data of the pierre auger fluorescence telescopes

The fluorescence detector (FD) of the Pierre Auger Observatory is currently operating 18 fluorescence telescopes of the 24 that will be employed in the completed detector. These telescopes, grouped in 4 eyes each consisting of 6 telescopes, measure the longitudinal profile of cosmic ray showers with a 14% duty cycle. The reconstruction capability and triggering efficiency have been studied using a complete simulation and reconstruction production chain, employing both simulated CORSIKA showers and parameterized Gaisser-Hillas profiles. The propagation through the atmosphere and the detector response are taken into account and simulated in detail. These simulated data have been generated in a preliminary analysis using the method of importance sampling to efficiently cover the energy region of 0.3-300 EeV, various shower geometries and impact points and different primary particles. The distributions of observables have then been investigated in both real and simulated data, facilitating the validation of the reconstruction and simulation software. Comparisons of real and simulated data are discussed and used to assess their impact on the data analysis.
Date: July 1, 2005
Creator: Ewers, A.; Greenen, H.; Kampert, K-H.; Perrone, L.; Robbins, S.; Scherini, V. et al.
System: The UNT Digital Library
Measurement of the ttbar production cross section in ppbar collisions at s**(1/2) = 1.96 TeV using lepton plus jets events (open access)

Measurement of the ttbar production cross section in ppbar collisions at s**(1/2) = 1.96 TeV using lepton plus jets events

We present the measurement of the top quark pair production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using 318 pb{sup -1} of data collected by the CDF detector at the Fermilab Tevatron. We measure the cross section in events with one high transverse momentum electron or muon, large missing transverse energy and three or more jets, where at least one bottom quarks from the top quark decay is identified via a secondary vertex tagging algorithm. The measured t{bar t} cross section is 8.7{sub -0.9}{sup +0.9}(stat){sub -0.9}{sup +1.2}(syst) pb, assuming a top quark mass of 178 GeV. The cross section measurement in the subsample in which both b-quark jets are identified gives 10.1{sub -1.4}{sup +1.6}(stat){sub -1.4}{sup +2.1}(syst) pb. We present one additional measurement of the t{bar t} cross section in the same dataset but without the b-tagging requirement. Top quark events are distinguished from the primary background of W boson production with associated jets using an artificial neural network method with a variety of kinematic quantities. This measurement uses a larger dataset albeit with a smaller t{bar t} fraction. The t{bar t} cross section without b-tagging is measured to be 6.0 {+-} 0.8(stat) {+-} 1.0(syst) pb.
Date: July 1, 2005
Creator: Guimaraes da Costa, Joao & U., /Harvard
System: The UNT Digital Library
QCD (&) event generators (open access)

QCD (&) event generators

Recent developments in QCD phenomenology have spurred on several improved approaches to Monte Carlo event generation, relative to the post-LEP state of the art. In this brief review, the emphasis is placed on approaches for (1) consistently merging fixed-order matrix element calculations with parton shower descriptions of QCD radiation, (2) improving the parton shower algorithms themselves, and (3) improving the description of the underlying event in hadron collisions.
Date: July 1, 2005
Creator: Skands, Peter Z.
System: The UNT Digital Library
Charmless b decays at CDF (open access)

Charmless b decays at CDF

The authors report on the charmless B decays measurements performed on 180 pb{sup -1} of data collected with the CDF II detector at the Fermilab Tevatron collider. This paper describes: the first observation of the decay mode B{sub s} {yields} K{sup +}K{sup -} and the measurement of the direct Cp asymmetry in the ({bar B}){sub d} {yields} K{sup {+-}}{pi}{sup {-+}} decay; the first evidence of the decay mode B{sub s} {yields} {phi}{phi} and the branching ratio and Cp asymmetry for the B{sup {+-}} {yields} {phi}K{sup {+-}} decay.
Date: July 1, 2005
Creator: Donega, Mauro & U., /Geneva
System: The UNT Digital Library
Model independent measurement of S-wave K- pi+ systems using D+ ---> K pi pi decays from Fermilab E791 (open access)

Model independent measurement of S-wave K- pi+ systems using D+ ---> K pi pi decays from Fermilab E791

A model-independent partial-wave analysis of the S-wave component of the K{pi} system from decays of D{sup +} mesons to the three-body K{sup -}{pi}{sup +}{pi}{sup +} final state is described. Data come from the Fermilab E791 experiment. Amplitude measurements are made independently for ranges of K{sup -}{pi}{sup +} invariant mass, and results are obtained below 825 MeV/c{sup 2}, where previous measurements exist only in two mass bins. This method of parametrizing a three-body decay amplitude represents a new approach to analyzing such decays. Though no model is required for the S-wave, a parametrization of the relatively well-known reference P- and D-waves, optimized to describe the data used, is required. The observed phase variation for the S-, P- and D-waves do not match existing measurements of I = 1/2 K{sup -} {pi}{sup +} scattering in the invariant mass range in which scattering is predominantly elastic. If the data are mostly I = 1/2, this observation indicates that the Watson theorem, which requires these phases to have the same dependence on invariant mass, does not apply to these decays. The production rate of K{sup -}{pi}{sup +} from these decays, if assumed to be predominantly I = 1/2, is also found to have a …
Date: July 1, 2005
Creator: Aitala, E. M.; Amato, S.; Anjos, J. C.; Appel, J. A.; Ashery, D.; Banerjee, S. et al.
System: The UNT Digital Library