Resource Type

122 Matching Results

Results open in a new window/tab.

62-TeV center of mass hadron collider with superbunch beams (open access)

62-TeV center of mass hadron collider with superbunch beams

The scheme of a 62-TeV center of mass p-p collider with superbunch beams at Fermilab is proposed as a practical and realistically achievable future project. It will be built in two stages, using the same tunnel, first with a 2 Tesla low field magnet collider ring and later with a 10 Tesla high field magnet collider ring. Both low and high field magnets have twin bore aperture and will be installed in the tunnel with the circumference of 87.25 km. In each bore a proton beam is accelerated, using induction cavities to increase luminosity. In the first stage they install a 7 TeV accelerator ring with operating field of 2 Tesla, based on the superferric transmission-line design. This ring will be operated at a 14-TeV center of mass collider. This will have the same energy as the LHC, but it will have 15 times higher luminosity, namely 1.5 x 10{sup 35}/cm{sup 2}/sec. The estimated synchrotron radiation is negligible with this machine. The existing Fermilab accelerator system, including the 150 GeV main injector, will be used as the injector system. Its rough cost estimation and schedule for this first stage are presented. In the second stage proton beams are accelerated, also …
Date: November 5, 2001
Creator: al., Ryuji Yamada et
System: The UNT Digital Library
ACCOMPLISHMENTS OF THE AMERICAN-POLISH PROGRAM FOR ELIMINATION OF LOW EMISSIONS IN KRAKOW (open access)

ACCOMPLISHMENTS OF THE AMERICAN-POLISH PROGRAM FOR ELIMINATION OF LOW EMISSIONS IN KRAKOW

In 1991, US and Polish officials signed a Memorandum of Understanding formally initiating and directing the Cracow Clean Fossil Fuels and Energy Efficiency Program. Developing a program approach for the most effective use of the available funds required considerable effort on the part of all project participants. The team recognized early that the cost of solving the low emissions problem even in only one city far exceeded the amount of available US funds. Economic conditions in Poland limited availability of local capital funds for environmental projects. Imposing environmental costs on struggling companies or city residents under difficult conditions of the early 1990's required careful consideration of the economic and political impacts. For all of these reasons the program sought to identify technologies for achieving air quality goals which, through improved efficiency and/or reduced fuel cost, could be so attractive economically as to lead to self-sustaining activities beyond the end of the formal project. The effort under this program has been focused into 5 main areas of interest as follows: (1) Energy Conservation and Extension of Central Station District Heating; (2) Replacement of Coal- and Coke-Fired Boilers with Natural Gas-Fired Boilers; (3) Replacement of Coal-Fired Home Stoves with Electric Heating Appliances; …
Date: November 5, 1998
Creator: BUTCHER,T.A. & PIERCE,B.
System: The UNT Digital Library
ACCUMULATION OF RADIOCESIUM BY MUSHROOMS IN THE ENVIRONMENT: A LITERATURE REVIEW AND IMAGE GALLERY (open access)

ACCUMULATION OF RADIOCESIUM BY MUSHROOMS IN THE ENVIRONMENT: A LITERATURE REVIEW AND IMAGE GALLERY

During the last 50 years, a large amount of information on radionuclide accumulators or 'sentinel-type' organisms in the environment has been published. Much of this work focused on the risks of food-chain transfer of radionuclides to higher organisms such as reindeer and man. However, until the 1980's and 1990's, there has been little published data on the radiocesium ({sup 134}Cs and {sup 137}Cs) accumulation by mushrooms. This presentation will consist of a review of the published data for {sup 134,137}Cs accumulation by mushrooms in nature. The review will consider the time of sampling, sample location characteristics, the radiocesium source term and other aspects that promote {sup 134,137}Cs uptake by mushrooms. This review will focus on published data for mushrooms that demonstrate a large propensity for use in the environmental biomonitoring of radiocesium contamination. It will also provide photographs and descriptions of habitats for many of these mushrooms to facilitate their collection for biomonitoring.
Date: November 5, 2006
Creator: Duff, M & Mary Ramsey, M
System: The UNT Digital Library
AIR PERMIT COMPLIANCE FOR WASTE RETRIEVAL OEPRATIONS INVOLVING MULTI-UNIT OPERATIONS (open access)

AIR PERMIT COMPLIANCE FOR WASTE RETRIEVAL OEPRATIONS INVOLVING MULTI-UNIT OPERATIONS

Since 1970, approximately 38,000 suspect-transuranic and transuranic waste containers have been placed in retrievable storage on the Hanford Site in the 200 Areas burial grounds. Hanford's Waste Retrieval Project is retrieving these buried containers and processing them for safe storage and disposition. Container retrieval activities require an air emissions permit to account for potential emissions of radionuclides. The air permit covers the excavation activities as well as activities associated with assaying containers and installing filters in the retrieved transuranic containers lacking proper venting devices. Fluor Hanford, Inc. is required to track radioactive emissions resulting from the retrieval activities. Air, soil, and debris media contribute to the emissions and enabling assumptions allow for calculation of emissions. Each of these activities is limited to an allowed annual emission (per calendar year) and .contributes to the overall total emissions allowed for waste retrieval operations. Tracking these emissions is required to ensure a permit exceedance does not occur. A tracking tool was developed to calculate potential emissions in real time sense. Logic evaluations are established within the tracking system to compare real time data against license limits to ensure values are not exceeded for either an individual activity or the total limit. Data input …
Date: November 5, 2007
Creator: FM, SIMMONS
System: The UNT Digital Library
Alignment tolerances of IR quadrupoles in the LHC (open access)

Alignment tolerances of IR quadrupoles in the LHC

Luminosity in the LHC will depend critically on the alignment of the triplet quadrupoles. These quadrupoles are closest to the interaction points (IPs), have large gradients and the {beta} functions have their largest values within these quadrupoles. Within a triplet, the cold masses of the Q1 and Q3 quadrupoles will be housed in separate cryostats while Q2a and Q2b will be placed in a single cryostat. The absolute alignments of Q1, Q3 and the Q2a/Q2b pair with respect to the desired axes will be determined during installation. The relative alignment of Q2a and Q2b however will be fixed once they are placed in their common cryostat at Fermilab. In this note, we examine the required relative alignment tolerances of Q2a and Q2b. An early study of some alignment tolerances was done by Weisz [1].
Date: November 5, 1999
Creator: Sen, Tanaji
System: The UNT Digital Library
Analysis of Dry Storage Temperature Limits for Zircaloy-Clad Spent Nuclear Fuel (open access)

Analysis of Dry Storage Temperature Limits for Zircaloy-Clad Spent Nuclear Fuel

Safe interim dry storage of spent nuclear fuel (SNF) must be maintained for a minimum of twenty years according to the Code of Federal Regulations. The most important variable that must be regulated by dry storage licensees in order to meet current safety standards is the temperature of the SNF. The two currently accepted models to define the maximum allowable initial storage temperature for SNF are based on the diffusion controlled cavity growth (DCCG) failure mechanism proposed by Raj and Ashby. These models may not give conservative temperature limits. Some have suggested using a strain-based failure model to predict the maximum allowable temperatures, but we have shown that this is not applicable to the SNF as long as DCCG is the assumed failure mechanism. Although the two accepted models are based on the same fundamental failure theory (DCCG), the researchers who developed the models made different assumptions, including selection of some of the most critical variables in the DCCG failure equation. These inconsistencies are discussed together with recommended modifications to the failure models based on more recent data.
Date: November 5, 1999
Creator: Hayes, T.A.; Kassner, M.D. & Vecchio, K.S.
System: The UNT Digital Library
Anisotropic optical properties of single Si2Te3 nanoplates (open access)

Anisotropic optical properties of single Si2Te3 nanoplates

Article reporting a combined experimental and computational study of the optical properties of individual silicon telluride (Si2Te3) nanoplates.
Date: November 5, 2020
Creator: Chen, Jiyang; Bhattarai, Romakanta; Cui, Jingbiao; Shen, Xiao & Hoang, Thang
System: The UNT Digital Library
Antiferromagnetic exchange bias of a ferromagnetic semiconductor by a ferromagnetic metal (open access)

Antiferromagnetic exchange bias of a ferromagnetic semiconductor by a ferromagnetic metal

We demonstrate an exchange bias in (Ga,Mn)As induced by antiferromagnetic coupling to a thin overlayer of Fe. Bias fields of up to 240 Oe are observed. Using element-specific x-ray magnetic circular dichroism measurements, we distinguish an interface layer that is strongly pinned antiferromagnetically to the Fe. The interface layer remains polarized at room temperature.
Date: November 5, 2009
Creator: Olejnik, K.; Wadley, P.; Haigh, J.; Edmonds, K. W.; Campion, R. P.; Rushforth, A. W. et al.
System: The UNT Digital Library
Applications and advances of positron beam spectroscopy: appendix a (open access)

Applications and advances of positron beam spectroscopy: appendix a

Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory jointly sponsored by the DOE-Division of Materials Science, The Materials Research Institute at LLNL and the University of California Presidents Office. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques will play in materials analysis and the demand for the data. There were general discussions lead by review talks on positron analysis techniques, and their applications to problems in semiconductors, polymers and composites, metals and engineering materials, surface analysis and advanced techniques. These were followed by focus sessions on positron analysis opportunities in these same areas. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of science based stockpile stewardship. There was a detailed discussion of the LLNL capabilities and a tour …
Date: November 5, 1997
Creator: Howell, R. H.
System: The UNT Digital Library
Assessment of alternatives for long-term management of uranium ore residues and contaminated soils located at DOE's Niagara Falls Storage Site (open access)

Assessment of alternatives for long-term management of uranium ore residues and contaminated soils located at DOE's Niagara Falls Storage Site

About 11,000 m/sup 3/ of uranium ore residues and 180,000 m/sup 3/ of wastes (mostly slightly contaminated soils) are consolidated within a diked containment area at the Niagara Falls Storage Site (NFSS) located about 30 km north of Buffalo, NY. The residues account for less than 6% of the total volume of contaminated materials but almost 99% of the radioactivty. The average /sup 226/Ra concentration in the residues is 67,000 pCi/g. Several alternatives for long-term management of the wastes and residues are being considered, including: improvement of the containment at NFSS, modification of the form of the residues, management of the residues separately from the wastes, management of the wastes and residues at another humid site (Oak Ridge, TN) or arid site (Hanford, WA), and dispersal of the wastes in the ocean. Potential radiological risks are expected to be smaller than the nonradiological risks of occupational and transportation-related injuries and deaths. Dispersal of the slightly contaminated wastes in the ocean is not expected to result in any significant impacts on the ocean environment or pose any significant radiological risk to humans. It will be necessary to take perpetual care of the near-surface burial sites because the residues and wastes will …
Date: November 5, 1984
Creator: Merry-Libby, P.
System: The UNT Digital Library
Assessment of some of the problems in the USA of superconducting magnets for fusion research (open access)

Assessment of some of the problems in the USA of superconducting magnets for fusion research

This paper discusses some of the general difficulties and problems encountered during the development of the technology of superconductors and superconducting magnets for fusion and expresses some personal concerns.
Date: November 5, 1981
Creator: Cornish, D.N.
System: The UNT Digital Library
Asymptotic Diffusion-Limit Accuracy of Sn Angular Differencing Schemes (open access)

Asymptotic Diffusion-Limit Accuracy of Sn Angular Differencing Schemes

In a previous paper, Morel and Montry used a Galerkin-based diffusion analysis to define a particular weighted diamond angular discretization for S{sub n}n calculations in curvilinear geometries. The weighting factors were chosen to ensure that the Galerkin diffusion approximation was preserved, which eliminated the discrete-ordinates flux dip. It was also shown that the step and diamond angular differencing schemes, which both suffer from the flux dip, do not preserve the diffusion approximation in the Galerkin sense. In this paper we re-derive the Morel and Montry weighted diamond scheme using a formal asymptotic diffusion-limit analysis. The asymptotic analysis yields more information than the Galerkin analysis and demonstrates that the step and diamond schemes do in fact formally preserve the diffusion limit to leading order, while the Morel and Montry weighted diamond scheme preserves it to first order, which is required for full consistency in this limit. Nonetheless, the fact that the step and diamond differencing schemes preserve the diffusion limit to leading order suggests that the flux dip should disappear as the diffusion limit is approached for these schemes. Computational results are presented that confirm this conjecture. We further conjecture that preserving the Galerkin diffusion approximation is equivalent to preserving the …
Date: November 5, 2009
Creator: Bailey, T S; Morel, J E & Chang, J H
System: The UNT Digital Library
Band anticrossing in Group II-Ox-VI1-x highly mismatched alloys: Cd1-yMnyOxTe1-x quaternaries synthesized by O ion implantation (open access)

Band anticrossing in Group II-Ox-VI1-x highly mismatched alloys: Cd1-yMnyOxTe1-x quaternaries synthesized by O ion implantation

None
Date: November 5, 2001
Creator: Yu, K. M.; Walukiewicz, W.; Wu, J.; Beeman, J. W.; Ager, J. W., III; Haller, E. E. et al.
System: The UNT Digital Library
BOUT simulations of drift resistive ballooning L-mode turbulence in the edge of the DIII-D tokamak (open access)

BOUT simulations of drift resistive ballooning L-mode turbulence in the edge of the DIII-D tokamak

None
Date: November 5, 2012
Creator: Cohen, B. I.; Umansky, M. V.; Nevins, W. M.; Makowski, M.; Boedo, J.; Rudakov, D. et al.
System: The UNT Digital Library
BTeV level 1 vertex trigger (open access)

BTeV level 1 vertex trigger

BTeV is a B-physics experiment that expects to begin collecting data at the C0 interaction region of the Fermilab Tevatron in the year 2006. Its primary goal is to achieve unprecedented levels of sensitivity in the study of CP violation, mixing, and rare decays in b and c quark systems. In order to realize this, it will employ a state-of-the-art first-level vertex trigger (Level 1) that will look at every beam crossing to identify detached secondary vertices that provide evidence for heavy quark decays. This talk will briefly describe the BTeV detector and trigger, focus on the software and hardware aspects of the Level 1 vertex trigger, and describe work currently being done in these areas.
Date: November 5, 2001
Creator: Wang, Michael H.L.S.
System: The UNT Digital Library
Calculation of the substitutional fraction of ion-implanted He in an Fe target (open access)

Calculation of the substitutional fraction of ion-implanted He in an Fe target

None
Date: November 5, 2010
Creator: Erhart, P. & Marian, J.
System: The UNT Digital Library
I Cannot See You—The Perspectives of Deaf Students to Online Learning during COVID-19 Pandemic: Saudi Arabia Case Study (open access)

I Cannot See You—The Perspectives of Deaf Students to Online Learning during COVID-19 Pandemic: Saudi Arabia Case Study

This article investigates the e-learning experiences of deaf students, focusing on the college of the Technical and Vocational Training Corporation (TVTC) in the Kingdom of Saudi Arabia (KSA). Particularly, it studies the challenges and concerns faced by deaf students during the sudden shift to online learning. Results report problems with internet access, inadequate support, and inaccessibility of content from learning systems, among other issues. The authors argue that institutions should consider a procedure to create more accessible technology that is adaptable during the pandemic to serve individuals with diverse needs.
Date: November 5, 2021
Creator: Aljedaani, Wajdi; Aljedaani, Mona; AlOmar, Eman Abdullah; Mkaouer, Mohamed Wiem; Ludi, Stephanie & Khalaf, Yousef Bani
System: The UNT Digital Library
Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol (open access)

Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol

A detailed understanding of the sources, transformations, and fates of organic species in the environment is crucial because of the central roles that organics play in human health, biogeochemical cycles, and Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state (OSC), a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of OSC , using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number (nC).
Date: November 5, 2010
Creator: Technology, Massachusetts Institute of; Kroll, Jesse H.; Donahue, Neil M.; Jimenez, Jose L.; Kessler, Sean H.; Canagaratna, Manjula R. et al.
System: The UNT Digital Library
Catalytic epoxidation of propene with H2O-O2 reactants on Au/TiO2 (open access)

Catalytic epoxidation of propene with H2O-O2 reactants on Au/TiO2

Au/TiO{sub 2} catalysts form hydroperoxy species from H{sub 2}O-O{sub 2} mixtures at near-ambient temperatures. These species can be used in the selective epoxidation of propene to propylene oxide.
Date: November 5, 2008
Creator: Ojeda, Manuel & Iglesia, Enrique
System: The UNT Digital Library
The CDF data handling system (open access)

The CDF data handling system

The Collider Detector at Fermilab (CDF) records proton-antiproton collisions at center of mass energy of 2.0 TeV at the Tevatron collider. A new collider run, Run II, of the Tevatron started in April 2001. Increased luminosity will result in about 1 PB of data recorded on tapes in the next two years. Currently the CDF experiment has about 260 TB of data stored on tapes. This amount includes raw and reconstructed data and their derivatives. The data storage and retrieval are managed by the CDF Data Handling (DH) system. This system has been designed to accommodate the increased demands of the Run II environment and has proven robust and reliable in providing reliable flow of data from the detector to the end user. This paper gives an overview of the CDF Run II Data Handling system which has evolved significantly over the course of this year. An outline of the future direction of the system is given.
Date: November 5, 2003
Creator: Litvintsev, Dmitry O.
System: The UNT Digital Library
The CDF TESTCLK module - Providing system level clocking and triggering for Run 2 prototyping crates (open access)

The CDF TESTCLK module - Providing system level clocking and triggering for Run 2 prototyping crates

The TESTCLK module was specifically designed for use in prototyping crates for the Colliding Detector Facility (CDF) Run 2 Experiment at Fermi National Accelerator Laboratory. The TESTCLK Module allows the user to supply system clocks and trigger signals to stand-alone crates. This module has allowed designers of the CDF Run 2 electronics to thoroughly test their modules, despite the lack of a DAQ system supplied clock and trigger interface. This paper will explore the features that were found important to incorporate into the TESTCLK, and describe how they were implemented. The paper will also describe how the TESTCLK module has been used to support the initial implementation of the DAQ system at CDF. This has allowed data taking and testing of CDF Electronic modules before production clock and trigger modules became available.
Date: November 5, 1999
Creator: Stuermer, Theresa Shaw and Walter
System: The UNT Digital Library
Comparing structural loads in large pools evaluated with the LUSH code and current design methods (open access)

Comparing structural loads in large pools evaluated with the LUSH code and current design methods

Large pools for storing spent fuel elements from nuclear reactors are being proposed to augment the present storage capacity of pools located at nuclear power plants and fuel reprocessing plants. These pools will be part of either independent spent fuel storage installations or large reprocessing plants. Because of the large size of the pools, seismic loads are of significant interest, and in particular the adequacy of current design methods for calculating seismic loads was of special concern. An evaluation of design methods representative of current practice was carried out, and the results are summarized. The evaluation was based on a comparison of total structural loads obtained by these methods with those obtained using the LUSH code. The LUSH code offered a combination of latest technologies in structural analysis involving soil-structure interaction.
Date: November 5, 1976
Creator: Dong, R. G.
System: The UNT Digital Library
Completing fault models for abductive diagnosis (open access)

Completing fault models for abductive diagnosis

In logic-based diagnosis, the consistency-based method is used to determine the possible sets of faulty devices. If the fault models of the devices are incomplete or nondeterministic, then this method does not necessarily yield abductive explanations of system behavior. Such explanations give additional information about faulty behavior and can be used for prediction. Unfortunately, system descriptions for the consistency-based method are often not suitable for abductive diagnosis. Methods for completing the fault models for abductive diagnosis have been suggested informally by Poole and by Cox et al. Here we formalize these methods by introducing a standard form for system descriptions. The properties of these methods are determined in relation to consistency-based diagnosis and compared to other ideas for integrating consistency-based and abductive diagnosis.
Date: November 5, 1992
Creator: Knill, E. (Los Alamos National Lab., NM (United States)); Cox, P.T. & Pietrzykowski, T. (Technical Univ., NS (Canada))
System: The UNT Digital Library
Completing fault models for abductive diagnosis (open access)

Completing fault models for abductive diagnosis

In logic-based diagnosis, the consistency-based method is used to determine the possible sets of faulty devices. If the fault models of the devices are incomplete or nondeterministic, then this method does not necessarily yield abductive explanations of system behavior. Such explanations give additional information about faulty behavior and can be used for prediction. Unfortunately, system descriptions for the consistency-based method are often not suitable for abductive diagnosis. Methods for completing the fault models for abductive diagnosis have been suggested informally by Poole and by Cox et al. Here we formalize these methods by introducing a standard form for system descriptions. The properties of these methods are determined in relation to consistency-based diagnosis and compared to other ideas for integrating consistency-based and abductive diagnosis.
Date: November 5, 1992
Creator: Knill, E.; Cox, P. T. & Pietrzykowski, T.
System: The UNT Digital Library