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Sample records for alamos critical experiment

  1. The Pajarito Site operating procedures for the Los Alamos Critical Experiments Facility

    SciTech Connect

    Malenfant, R.E.

    1991-12-01

    Operating procedures consistent with DOE Order 5480.6, and the American National Standard Safety Guide for the Performance of Critical Experiments are defined for the Los Alamos Critical Experiments Facility (LACEF) of the Los Alamos National Laboratory. These operating procedures supersede and update those previously published in 1983 and apply to any criticality experiment performed at the facility. 11 refs.

  2. Dosimetry at the Los Alamos Critical Experiments Facility: Past, present, and future

    SciTech Connect

    Malenfant, R.E.

    1993-10-01

    Although the primary reason for the existence of the Los Alamos Critical Experiments Facility is to provide basic data on the physics of systems of fissile material, the physical arrangements and ability to provide sources of radiation have led to applications for all types of radiation dosimetry. In the broad definition of radiation phenomena, the facility has provided sources to evaluate biological effects, radiation shielding and transport, and measurements of basic parameters such as the evaluation of delayed neutron parameters. Within the last 15 years, many of the radiation measurements have been directed to calibration and intercomparison of dosimetry related to nuclear criticality safety. Future plans include (1) the new applications of Godiva IV, a bare-metal pulse assembly, for dosimetry (including an evaluation of neutron and gamma-ray room return); (2) a proposal to relocate the Health Physics Research Reactor from the Oak Ridge National Laboratory to Los Alamos, which will provide the opportunity to continue the application of a primary benchmark source to radiation dosimetry; and (3) a proposal to employ SHEBA, a low-enrichment solution assembly, for accident dosimetry and evaluation.

  3. Critical partnerships: Los Alamos, universities, and industry

    SciTech Connect

    Berger, C.L.

    1997-04-01

    Los Alamos National Laboratory, situated 35 miles northwest of Santa Fe, NM, is one of the Department of Energy`s three Defense Programs laboratories. It encompasses 43 square miles, employees approximately 10,000 people, and has a budget of approximately $1.1B in FY97. Los Alamos has a strong post-cold war mission, that of reducing the nuclear danger. But even with that key role in maintaining the nation`s security, Los Alamos views partnerships with universities and industry as critical to its future well being. Why is that? As the federal budget for R&D comes under continued scrutiny and certain reduction, we believe that the triad of science and technology contributors to the national system of R&D must rely on and leverage each others capabilities. For us this means that we will rely on these partners to help us in 5 key ways: We expect that partnerships will help us maintain and enhance our core competencies. In doing so, we will be able to attract the best scientists and engineers. To keep on the cutting edge of research and development, we have found that partnerships maintain the excellence of staff through new and exciting challenges. Additionally, we find that from our university and corporate partners we often learn and incorporate {open_quotes}best practices{close_quotes} in organizational management and operations. Finally, we believe that a strong national system of R&D will ensure and enhance our ability to generate revenues.

  4. Radiological dose assessment for bounding accident scenarios at the Critical Experiment Facility, TA-18, Los Alamos National Laboratory

    SciTech Connect

    1991-09-01

    A computer modeling code, CRIT8, was written to allow prediction of the radiological doses to workers and members of the public resulting from these postulated maximum-effect accidents. The code accounts for the relationships of the initial parent radionuclide inventory at the time of the accident to the growth of radioactive daughter products, and considers the atmospheric conditions at time of release. The code then calculates a dose at chosen receptor locations for the sum of radionuclides produced as a result of the accident. Both criticality and non-criticality accidents are examined.

  5. Los Alamos personnel and area criticality dosimeter systems

    SciTech Connect

    Vasilik, D.G.; Martin, R.W.

    1981-06-01

    Fissionable materials are handled and processed at the Los Alamos National Laboratory. Although the probability of a nuclear criticality accident is very remote, it must be considered. Los Alamos maintains a broad spectrum of dose assessment capabilities. This report describes the methods employed for personnel neutron, area neutron, and photon dose evaluations with passive dosimetry systems.

  6. Exploration geochemistry: The Los Alamos experience

    SciTech Connect

    Maassen, L.W.; Bolivar, S.L.

    1989-01-01

    Los Alamos National Laboratory became actively involved in geochemical exploration in 1975 by conducting a reconnaissance-scale exploration program for uranium as part of the National Uranium Resource Evaluation program. Initially, only uranium and thorium were analyzed. By 1979 Los Alamos was analyzing a multielement suite. The data were presented in histograms and as black and white concentration plots for uranium and thorium only. Data for the remaining elements were presented as hard copy data listings in an appendix to the report. In 1983 Los Alamos began using exploration geochemistry for the purpose of finding economic mineral deposits to help stimulate the economies of underdeveloped countries. Stream-sediment samples were collected on the Caribbean island of St. Lucia and a geochemical atlas of that island was produced. The data were statistically smoothed and presented as computer-generated color plots of each element of the multielement suite. Studies for the US Bureau of Land Management in 1984 consisted of development of techniques for the integration of several large data sets, which could then be used for computer-assisted mineral resource assessments. A supervised classification technique was developed which compares the attributes of grid cells containing mines or mineral occurrences with attributes of unclassified cells not known to contain mines or occurrences. Color maps indicate how closely unclassified cells match in attributes the cells with mines or occurrences. 20 refs., 1 fig., 1 tab.

  7. Experiments on planar plasma flow switches at Los Alamos

    SciTech Connect

    Benage, J.F. Jr.; Wysocki, F.J.; Bowers, R.; Oona, H.

    1997-12-01

    The authors have performed a series of experiments on the Colt facility at Los Alamos to study the performance of plasma flow switches and to understand the important physics issues which affect that performance. These experiments were done in planar geometry on a small machine to allow for better diagnostic access and a higher repetition rate. The Colt facility is a capacitor bank which stores 300 kJ at maximum charge and produced a peak current of 1.1 MA in 2.0 microseconds for these experiments. The diagnostics used for these experiments included an array of b-dot probes, visible framing pictures, visible spectroscopy, and laser interferometry. Characteristics of the switch are determined from spatial and temporal profiles of the magnetic field and the spatial profile and temperature of the switch plasma. Here the authors present results from experiments for a variety of switch conditions.

  8. Critical experiment data archiving

    SciTech Connect

    Koponen, B.L. ); Clayton, E.D.; Doherty, A.L. )

    1991-01-01

    Critical experiment facilities produced a large number of important data during the past 45 years; however, many useful data remain unpublished. The unpublished material exists in the form of experimenters' logbooks, notes, photographs, material descriptions, etc., This data could be important for computer code validation, understanding the physics of criticality, facility design, or for setting process limits. In the past, criticality specialists have been able to obtain unpublished details by direct contact with the experimenters. Obviously, this will not be possible indefinitely. Most of the US critical experiment facilities are now closed, and the experimenters are moving to other jobs, retiring, or otherwise becoming unavailable for this informal assistance. Also, the records are in danger of being discarded or lost during facility closures, cleanup activities, or in storage. A project was begun in 1989 to ensure that important unpublished data from critical experiment facilities in the United States are archived and made available as a resource of the US Department of Energy's (DOE's) Nuclear Criticality Information System (NCIS). The objective of this paper is to summarize the project accomplishments to date and bring these activities to the attention of those who might be aware of the location of source information needed for archiving and could assist in getting the materials included in the archive.

  9. National Criticality Experiments Research Center: Capability and Status

    SciTech Connect

    Hayes, David K.; Myers, William L.

    2012-07-12

    After seven years, the former Los Alamos Critical Experiments Facility (LACEF), or Pajarito Site, has reopened for business as the National Criticality Experiments Research Center (NCERC) at the Nevada National Security Site (NNSS). Four critical assembly machines (Comet, Planet, Flat-Top, and Godiva-IV) made the journey from Los Alamos to the NNSS. All four machines received safety system upgrades along with new digital control systems. Between these machines, systems ranging from the thermal through the intermediate to the fast spectrum may be assembled. Steady-State, transient, and super-prompt critical conditions may be explored. NCERC is the sole remaining facility in the United States capable of conducting general-purpose nuclear materials handling including the construction and operation of high-multiplication assemblies, delayed critical assemblies, and prompt critical assemblies. Reconstitution of the unique capabilities at NCERC ensures the viability of (1) The Nuclear Renaissance, (2) Stockpile Stewardship, and (3) and the next generation of criticality experimentalists.

  10. "Reminiscences of Los Alamos": Narrative, Critical Theory, and the Organizational Subject.

    ERIC Educational Resources Information Center

    Taylor, Bryan C.

    1990-01-01

    Examines autobiographical narratives of three scientists from the wartime Los Alamos Laboratory. Finds an organizational structure manifest in ideological discourses for nuclear practice and sensemaking, permitting rationalization for working identities and labor objectives. Considers implications for the critical study of organizational…

  11. Neutron Capture Experiments Using the DANCE Array at Los Alamos

    SciTech Connect

    Dashdorj, D.; Mitchell, G. E.; Baramsai, B.; Chyzh, A.; Walker, C.; Agvaanluvsan, U.; Becker, J. A.; Parker, W.; Sleaford, B.; Wu, C. Y.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Krticka, M.; Becvar, F.

    2009-03-31

    The Detector for Advanced Neutron Capture Experiments (DANCE) is designed for neutron capture measurements on very small and/or radioactive targets. The DANCE array of 160 BaF{sub 2} scintillation detectors is located at the Lujan Center at the Los Alamos Neutron Science Center (LANSCE). Accurate measurements of neutron capture data are important for many current applications as well as for basic understanding of neutron capture. The gamma rays following neutron capture reactions have been studied by the time-of-flight technique using the DANCE array. The high granularity of the array allows measurements of the gamma-ray multiplicity. The gamma-ray multiplicities and energy spectra for different multiplicities can be measured and analyzed for spin and parity determination of the resolved resonances.

  12. Nuclear-accident dosimetry: measurements at the Los Alamos SHEBA critical assembly

    SciTech Connect

    Vasilik, D.G.; Martin, R.W.; Fuller, D.

    1981-07-01

    Criticality dosimeters were exposed to different degraded neutron and gamma-ray energy spectra from the Los Alamos Solution High Energy Burst Assembly (SHEBA). The liquid critical test assembly was operated in the continuous mode to provide a mixed source of neutron and gamma-ray radiation for the evaluation of Los Alamos criticality detector systems. Different neutron and gamma-ray spectra were generated by operating the reactor (a) shielded by 12 cm of Lucite, (b) unshielded, (c) shielded by 20 cm of concrete, and (d) shielded by 15 cm of steel. This report summarizes the dosimetry measurements conducted for these different configurations. In-air measurements were conducted with shielded and unshielded area and personnel dosimeters. Phantom measurements were made using personnel dosimeters. Combined blood-sodium and hair sulfur activation measurements of absorbed dose were also made. In addition, indium foils placed on phantoms were evaluated for the purpose of screening personnel for radiation exposure.

  13. Los Alamos beam halo experiment: comparing theory, simulation and experiment.

    SciTech Connect

    Wangler, Thomas P.,; Qiang, J.

    2002-01-01

    We compare macroparticle simulations with measurements from a proton beam-halo experiment in a 52-quadrupole periodic-focusing channel. Three different initial distributions with the same Courant-Snyder parameters and emittances, but different shapes, predict different beam profiles in the transport system. Input distributions with greater population in the tails produce larger rates of emittance growth, a result that is qualitatively consistent with the particle-core model of halo formation in mismatched beams. The simulations underestimate the growth rate of halo and emittance for mismatched beams. Better agreement between simulations and experiment may require an input distribution that represents more accurately the tails of the real input beam.

  14. The Criticality Safety Information Resource Center (CSIRC) at Los Alamos National Laboratory

    SciTech Connect

    Henderson, B.D.; Meade, R.A.; Pruvost, N.L.

    1999-09-20

    The Criticality Safety Information Resource Center (CSIRC) at Los Alamos National Laboratory (LANL) is a program jointly funded by the U.S. Department of Energy (DOE) and the U.S. Nuclear Regulatory Commission (NRC) in conjunction with the Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 97-2. The goal of CSIRC is to preserve primary criticality safety documentation from U.S. critical experimental sites and to make this information available for the benefit of the technical community. Progress in archiving criticality safety primary documents at the LANL archives as well as efforts to make this information available to researchers are discussed. The CSIRC project has a natural linkage to the International Criticality Safety Benchmark Evaluation Project (ICSBEP). This paper raises the possibility that the CSIRC project will evolve in a fashion similar to the ICSBEP. Exploring the implications of linking the CSIRC to the international criticality safety community is the motivation for this paper.

  15. Nuclear criticality safety staff training and qualifications at Los Alamos National Laboratory

    SciTech Connect

    Monahan, S.P.; McLaughlin, T.P.

    1997-05-01

    Operations involving significant quantities of fissile material have been conducted at Los Alamos National Laboratory continuously since 1943. Until the advent of the Laboratory`s Nuclear Criticality Safety Committee (NCSC) in 1957, line management had sole responsibility for controlling criticality risks. From 1957 until 1961, the NCSC was the Laboratory body which promulgated policy guidance as well as some technical guidance for specific operations. In 1961 the Laboratory created the position of Nuclear Criticality Safety Office (in addition to the NCSC). In 1980, Laboratory management moved the Criticality Safety Officer (and one other LACEF staff member who, by that time, was also working nearly full-time on criticality safety issues) into the Health Division office. Later that same year the Criticality Safety Group, H-6 (at that time) was created within H-Division, and staffed by these two individuals. The training and education of these individuals in the art of criticality safety was almost entirely self-regulated, depending heavily on technical interactions between each other, as well as NCSC, LACEF, operations, other facility, and broader criticality safety community personnel. Although the Los Alamos criticality safety group has grown both in size and formality of operations since 1980, the basic philosophy that a criticality specialist must be developed through mentoring and self motivation remains the same. Formally, this philosophy has been captured in an internal policy, document ``Conduct of Business in the Nuclear Criticality Safety Group.`` There are no short cuts or substitutes in the development of a criticality safety specialist. A person must have a self-motivated personality, excellent communications skills, a thorough understanding of the principals of neutron physics, a safety-conscious and helpful attitude, a good perspective of real risk, as well as a detailed understanding of process operations and credible upsets.

  16. Critical assembly: A technical history of Los Alamos during the Oppenheimer years, 1943--1945

    SciTech Connect

    Hoddeson, L.; Henriksen, P.W.; Meade, R.A.; Westfall, C.

    1993-11-01

    This volume treats the technical research that led to the first atomic bombs. The authors explore how the ``critical assembly`` of scientists, engineers, and military Personnel at Los Alamos collaborated during World War II, blending their traditions to create a new approach to large-scale research. The research was characterized by strong mission orientation, multidisciplinary teamwork, expansion of the scientists` traditional methodology with engineering techniques, and a trail-and-error methodology responding to wartime deadlines. The book opens with an introduction laying out major themes. After a synopsis of the prehistory of the bomb project, from the discovery of nuclear fission to the start of the Manhattan Engineer District, and an overview of the early materials program, the book examines the establishment of the Los Alamos Laboratory, the implosion and gun assembly programs, nuclear physics research, chemistry and metallurgy, explosives, uranium and plutonium development, confirmation of spontaneous fission in pile-produced plutonium, the thermonuclear bomb, critical assemblies, the Trinity test, and delivery of the combat weapons.

  17. History of critical experiments at Pajarito Site

    SciTech Connect

    Paxton, H.C.

    1983-03-01

    This account describes critical and subcritical assemblies operated remotely at the Pajarito Canyon Site at the Los Alamos National Laboratory. Earliest assemblies, directed exclusively toward the nuclear weapons program, were for safety tests. Other weapon-related assemblies provided neutronic information to check detailed weapon calculations. Topsy, the first of these critical assemblies, was followed by Lady Godiva, Jezebel, Flattop, and ultimately Big Ten. As reactor programs came to Los Alamos, design studies and mockups were tested at Pajarito Site. For example, nearly all 16 Rover reactors intended for Nevada tests were preceded by zero-power mockups and proof tests at Pajarito Site. Expanded interest and capability led to fast-pulse assemblies, culminating in Godiva IV and Skua, and to the Kinglet and Sheba solution assemblies.

  18. Dose reconstruction for weapons experiments involving 140La at Los Alamos National Laboratory, 1944-1962.

    PubMed

    Kraig, D H

    1997-10-01

    A series of 254 weapons design experiments was conducted by Los Alamos National Laboratory from 1944 through 1962 and resulted in the dispersal of approximately 11 PBq (300 kCi) of radioactive 140La. All shots occurred at Point Able in Bayo Canyon, east of the Los Alamos townsite. Public interest and the Government Accounting Office probe precipitated a dose reconstruction to assess potential exposures to members of the public. The information available for each shot included explosive charge size, date and time of explosion, and shot activity. Detailed meteorological data were not available for the majority of the shots, requiring the development of statistically representative meteorological data. A wind rose was developed specific to the afternoon-evening time of the shots, and the wind frequency in each sector was used to determine the fraction of activity dispersed towards each hypothetical receptor. HOTSPOT 7, a Gaussian plume-based dispersion model, was used to determine the average dose per sector per unit of shot activity. The dose from penetrating radiation from ground-deposited 140La was greater by several orders of magnitude than the dose from inhalation and immersion. The highest doses to a permanent resident probably occurred in the easternmost part of the Los Alamos townsite. The highest annual dose occurred in 1955 and was approximately 0.23 mSv. Assuming an individual had been at the location of maximum potential exposure in the Los Alamos townsite continuously throughout the experiments, the total dose from the 18-y series would have been approximately 1.4 mSv with an average dose of approximately 0.09 mSv y(-1). Doses at nearby Totavi trailer park, San Ildefonso Pueblo, and Santa Clara Pueblo were approximately 75%, 40%, and 15%, respectively, of those at Los Alamos. Visitors to nearby public areas received negligible doses. PMID:9314221

  19. The Los Alamos megamp fiber z-pinch experiment

    SciTech Connect

    Scudder, D.W.; Shlachter, J.S.; Hammel, J.E.; Venneri, F.; Chrien, R. ); Lovberg, R.; Riley, R. )

    1990-01-01

    The HDZP-II experiment uses a 2 MV, 1.9 {Omega}, 1.2 MA, 100 ns risetime pulsed-power driver. Preliminary experiments have been performed at 600--800 kA (half the bank energy). Preliminary results show the plasma heating to several kilovolts (although a non-Maxwellian distribution is likely) while maintaining an overall straight and reasonably uniform axial configuration. However, interferograms and x-ray pinhole photographs show the column expanding rapidly with considerable small-scale structure, presumably due to m=0 activity. The neutron yield (typically 5 {times} 10{sup 9}) is consistent with thermonuclear reactions at the reduced density although detailed study of the neutron characteristics has not been performed. Preliminary isotropy measurements do not show significant neutron anisotropy. 10 refs.

  20. Modeling and analysis of high-explosive driven perturbed plate experiments at Los Alamos

    NASA Astrophysics Data System (ADS)

    Cooley, James H.; Olson, Russel T.; Oro, David

    2014-05-01

    We have carried out several experiments on the Los Alamos proton radiography (pRad) facility to explore the growth of perturbations subjected to shockless acceleration. These experiments have involved both Tantalum and depleted Uranium plates with various initial amplitudes. The experimental platform is based on the one first developed by Barnes et al. [1] and further advanced by Raevsky [2]. This paper presents both the data for these experiments and an initial attempt to model the experiments using the simulation code FLAG [3].

  1. Subpicosecond compression experiments at Los Alamos National Laboratory

    SciTech Connect

    Carlsten, B.E.; Russell, S.J.; Kinross-Wright, J.M.

    1995-09-01

    The authors report on recent experiments using a magnetic chicane compressor at 8 MeV. Electron bunches at both low (0.1 nC) and high (1 nC) charges were compressed from 20 ps to less than 1 ps (FWHM). A transverse deflecting rf cavity was used to measure the bunch length at low charge; the bunch length at high charge was inferred from an induced energy spread of the beam. The longitudinal centrifugal-space charge force is calculated using a point-to-point numerical simulation and is shown not to influence the energy-spread measurement.

  2. Environmental assessment for consolidation of certain materials and machines for nuclear criticality experiments and training

    SciTech Connect

    1996-05-21

    In support of its assigned missions and because of the importance of avoiding nuclear criticality accidents, DOE has adopted a policy to reduce identifiable nuclear criticality safety risks and to protect the public, workers, government property and essential operations from the effects of a criticality accident. In support of this policy, the Los Alamos Critical Experiments Facility (LACEF) at the Los Alamos National Laboratory (LANL) Technical Area (TA) 18, provides a program of general purpose critical experiments. This program, the only remaining one of its kind in the United States, seeks to maintain a sound basis of information for criticality control in those physical situations that DOE will encounter in handling and storing fissionable material in the future, and ensuring the presence of a community of individuals competent in practicing this control.

  3. Subpicosecond Compression Experiments at Los Alamos National Laboratory

    SciTech Connect

    Carlsten, B.E.; Feldman, D.W.; Kinross-Wright, J.M.; Milder, M.L.; Russell, S.J.; Plato, J.G.; Sherwood, B.A.; Weber, M.E.; Cooper, R.G.; Sturges, R.E.

    1996-04-01

    We report on recent experiments using a magnetic chicane compressor at 8 MeV. Electron bunches at both low (0.1 nC) and high (1 nC) charges were compressed from 10{endash}15 ps to less than 1 ps (FWHM). A transverse deflecting rf cavity was used to measure the bunch length at low charge; the bunch length at high charge was inferred from the induced energy spread of the beam. The longitudinal centrifugal space-charge force [{ital Phys}. {ital Rev}. {ital E} {bold 51}, 1453 (1995)] is calculated using a point-to-point numerical simulation and is shown not to influence the energy-spread measurement. {copyright} {ital 1996 American Institute of Physics.}

  4. The Los Alamos National Laboratory source geometry experiment

    SciTech Connect

    Stump, B.W.; Pearson, D.C.; Edwards, C.L.; Baker, D.F.

    1995-09-01

    The Source Geometry Experiment was successfully conducted over the time period 17 April to 7 May 95. Recording in the mine was conducted 24 April to 4 May 95. Five single sources were instrumented that included four cylindrical charges at different burdens (distance from the free face) and a pseudo-spherical charge. Nine production shots conducted during the two week visit to the mine were also recorded. Included in these production shots were a number of explosions designed to primarily bulk (no cast) the overburden and a number which cast material into the mine pit. Instrumentation was divided into six primary types: (1) Near-source accelerometers were deployed at distances of approximately 20 to 300 m [14, three-component 25 g/volt accelerometers and 16, three-component 1 g/volt accelerometers]; (2) Linear array of velocity gauges to quantify wave propagation effects [4-11 three component strong motion velocity gauges]; (3)Far-field velocity gages deployed in an azimuthal array around the mine at ranges from 500 to 2500 m [8, three component velocity gauges]; (4) High speed film and multiple camera video designed to quantify the two and three dimensional affects around the explosions [2 high speed cameras and 3 Hi-8 video cameras]; (5) Velocity of detonation and detonation time measurements of selected explosions [2 VODR systems]; and (6) Pre and post shot laser survey. Any one shot had as many as 154 channels of data. Although the complete data set is still being assembled, quality checked and analyzed, it appears that nearly 2,000 channels of data were successfully recovered during the experiment. Preliminary analysis of the data illustrates the: (1) Significant spall accompanied both the cylindrical and spherical single sources; (2) Similarity of waveforms from the cylindrical and spherical single sources; (3) Strong variations in the body and surface wave generation from the nine production shot.

  5. Review of the Los Alamos FRX-C experiment

    SciTech Connect

    Siemon, R.E.; Armstrong, W.T.; Barnes, D.C.; Bartsch, R.R.; Chrien, R.E.; Cochrane, J.C.; Hugrass, W.; Kewish, R.W.; Klingner, P.L.; Lewis, H.R.

    1985-01-01

    The FRX-C device is a large field-reversed theta pinch experiment, with linear dimensions twice those of its FRX-A and FRX-B predecessors. It is used to form field-reversed configurations (FRCs), which are high-beta, highly prolate compact toroids. FRX-C has demonstrated an R/sup 2/ scaling for particle confinement in FRCs, indicating particles are lost by diffusive processes. Particle losses were also observed to dominate the energy balance. FRC lifetimes exceeding 300 ..mu..s were observed when weak quadrupole fields were applied to stabilize the n = 2 rotational mode. Detailed studies of the FRC equilibrium were performed using multi-chord and holographic interferometry. Measurements of electron temperature by Thomson scattering showed a flat profile and substantial losses through the electron channel. The loss rate of the internal poloidal flux of the FRC was observed to be anomalous and to scale less strongly with temperature than predicted from classical resistivity.

  6. A Re-Analysis of Historical Los Alamos Critical Assembly Reaction Rate Measurements

    NASA Astrophysics Data System (ADS)

    Kahler, A. C.; MacInnes, M.; Chadwick, M. B.

    2016-02-01

    Starting in the 1950s and continuing into the early 1970s, a number of foil irradiations and fission chamber measurements were made in a variety of Fast critical assemblies at Los Alamos National Laboratory. These include (i) Godiva, a bare HEU spherical assembly; (ii) Flattop-25, a spherical assembly consisting of an HEU core and a natural uranium reflector; (iii) Jezebel, a bare 239Pu assembly; and (iv) Flattop-Pu, a spherical assembly consisting of a 239Pu core and a natural uranium reflector. In most instances the irradiations occur at or near the center of the assembly, but in selected instances data were obtained for a radial traverse extending into the Flattop reflector region. Measurements were made for a number of threshold reactions, including 45Sc(n,2n)44mSc, 51V(n,α)48Sc, 75As(n,2n)74As, 89Y(n,2n)88Y, 90Zr(n,2n)89Zr, 103Rh(n,2n)102gRh, 107Ag(n,2n)106mAg, 169Tm(n,2n)168Tm, 175Lu(n,2n)174Lu, 191Ir(n,2n)190Ir, 197Au(n,2n)196Au, 203Tl(n,2n)202Tl, 204Pb(n,2n)203Pb and 238U(n,2n)237U. Fission ratio data for 238U(n,f)/235U(n,f) and 239Pu(n,f)/235U(n,f) were also obtained. We report C/E values from MCNP6 calculations using ENDF/B-VII.1 and IRDFF-v1.03 cross section data.

  7. First results from the Los Alamos plasma source ion implantation experiment

    SciTech Connect

    Rej, D.J.; Faehl, R.J.; Gribble, R.J.; Henins, I.; Kodali, P.; Nastasi, M.; Reass, W.A.; Tesmer, J.; Walter, K.C.; Wood, B.P.; Conrad, J.R.; Horswill, N.; Shamim, M.; Sridharan, K.

    1993-12-01

    A new facility is operational at Los Alamos to examine plasma source ion implantation on a large scale. Large workpieces can be treated in a 1.5-m-diameter, 4.6-m-long plasma vacuum chamber. Primary emphasis is directed towards improving tribological properties of metal surfaces. First experiments have been performed at 40 kV with nitrogen plasmas. Both coupons and manufactured components, with surface areas up to 4 m{sup 2}, have been processed. Composition and surface hardness of implanted materials are evaluated. Implant conformality and dose uniformity into practical geometries are estimated with multidimensional particle-in-cell computations of plasma electron and ion dynamics, and Monte Carlo simulations of ion transport in solids.

  8. MCNP{sup TM} criticality primer and training experiences

    SciTech Connect

    Briesmeister, J.; Forster, R.A.; Busch, R.

    1995-09-01

    With the closure of many experimental facilities, the nuclear criticality safety analyst is increasingly required to rely on computer calculations to identify safe limits for the handling and storage of fissile materials. However, the analyst may have little experience with the specific codes available at his or her facility. Usually, the codes are quite complex, black boxes capable of analyzing numerous problems with a myriad of input options. Documentation for these codes is designed to cover all the possible configurations and types of analyses but does not give much detail on any particular type of analysis. For criticality calculations, the user of a code is primarily interested in the value of the effective multiplication factor for a system (k{sub eff}). Most codes will provide this, and truckloads of other information that may be less pertinent to criticality calculations. Based on discussions with code users in the nuclear criticality safety community, it was decided that a simple document discussing the ins and outs of criticality calculations with specific codes would be quite useful. The Transport Methods Group, XTM, at Los Alamos National Laboratory (LANL) decided to develop a primer for criticality calculations with their Monte Carlo code, MCNP. This was a joint task between LANL with a knowledge and understanding of the nuances and capabilities of MCNP and the University of New Mexico with a knowledge and understanding of nuclear criticality safety calculations and educating first time users of neutronics calculations. The initial problem was that the MCNP manual just contained too much information. Almost everything one needs to know about MCNP can be found in the manual; the problem is that there is more information than a user requires to do a simple k{sub eff} calculation. The basic concept of the primer was to distill the manual to create a document whose only focus was criticality calculations using MCNP.

  9. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory's Source Region Program

    SciTech Connect

    Whitaker, R.W.; Noel, S.D.

    1992-12-01

    The summary report by Tom Weaver gives the overall background for the series of IVE (Integrated Verification Experiment) experiments including information on the full set of measurements made. This appendix presents details of the infrasound data for the and discusses certain aspects of a few special experiments. Prior to FY90, the emphasis of the Infrasound Program was on underground nuclear test (UGT) detection and yield estimation. During this time the Infrasound Program was a separate program at Los Alamos, and it was suggested to DOE/OAC that a regional infrasound network be established around NTS. The IVE experiments took place in a time frame that allowed simultaneous testing of possible network sites and examination of propagation in different directions. Whenever possible, infrasound stations were combined with seismic stations so that a large number could be efficiently fielded. The regional infrasound network was not pursued by DOE, as world events began to change the direction of verification toward non-proliferation. Starting in FY90 the infrasound activity became part of the Source Region Program which has a goal of understanding how energy is transported from the UGT to a variety of measurement locations.

  10. Critical point wetting drop tower experiment

    NASA Technical Reports Server (NTRS)

    Kaukler, W. F.; Tcherneshoff, L. M.; Straits, S. R.

    1984-01-01

    Preliminary results for the Critical Point Wetting CPW Drop Tower Experiment are produced with immiscible systems. Much of the observed phenomena conformed to the anticipated behavior. More drops will be needed to test the CPW theory with these immiscible systems.

  11. Fast critical experiment data for space reactors

    NASA Astrophysics Data System (ADS)

    Collins, P. J.; McFarlane, H. F.; Olsen, D. N.; Atkinson, C. A.; Ross, J. R.

    Data from a number of previous critical experiments exist that are relevant to the design concepts being considered for SP-100 and MMW space reactors. Although substantial improvements in experiment techniques have since made some of the measured quantities somewhat suspect, the basic criticality data are still useful in most cases. However, experiments require recalculation with modern computational methods and nuclear cross section data before they can be applied to today's designs. Recently, about 20 fast benchmark critical experiments were calculated with the latest ENDF/B data and modern transport codes. These calculations were undertaken as a part of the planning process for a new series of benchmark experiments aimed at supporting preliminary designs of SP-100 and MMW space reactors.

  12. Critical experiments with mixed oxide fuel

    SciTech Connect

    Harris, D.R.

    1997-06-01

    This paper very briefly outlines technical considerations in performing critical experiments on weapons-grade plutonium mixed oxide fuel assemblies. The experiments proposed would use weapons-grade plutonium and Er{sub 2}O{sub 3} at various dissolved boron levels, and for specific fuel assemblies such as the ABBCE fuel assembly with five large water holes. Technical considerations described include the core, the measurements, safety, security, radiological matters, and licensing. It is concluded that the experiments are feasible at the Rensselaer Polytechnic Institute Reactor Critical Facility. 9 refs.

  13. What's so critical about Critical Neuroscience? Rethinking experiment, enacting critique.

    PubMed

    Fitzgerald, Des; Matusall, Svenja; Skewes, Joshua; Roepstorff, Andreas

    2014-01-01

    In the midst of on-going hype about the power and potency of the new brain sciences, scholars within "Critical Neuroscience" have called for a more nuanced and sceptical neuroscientific knowledge-practice. Drawing especially on the Frankfurt School, they urge neuroscientists towards a more critical approach-one that re-inscribes the objects and practices of neuroscientific knowledge within webs of social, cultural, historical and political-economic contingency. This paper is an attempt to open up the black-box of "critique" within Critical Neuroscience itself. Specifically, we argue that limiting enactments of critique to the invocation of context misses the force of what a highly-stylized and tightly-bound neuroscientific experiment can actually do. We show that, within the neuroscientific experiment itself, the world-excluding and context-denying "rules of the game" may also enact critique, in novel and surprising forms, while remaining formally independent of the workings of society, and culture, and history. To demonstrate this possibility, we analyze the Optimally Interacting Minds (OIM) paradigm, a neuroscientific experiment that used classical psychophysical methods to show that, in some situations, people worked better as a collective, and not as individuals-a claim that works precisely against reactionary tendencies that prioritize individual over collective agency, but that was generated and legitimized entirely within the formal, context-denying conventions of neuroscientific experimentation. At the heart of this paper is a claim that it was precisely the rigors and rules of the experimental game that allowed these scientists to enact some surprisingly critical, and even radical, gestures. We conclude by suggesting that, in the midst of large-scale neuroscientific initiatives, it may be "experiment", and not "context", that forms the meeting-ground between neuro-biological and socio-political research practices. PMID:24910605

  14. SILENE Benchmark Critical Experiments for Criticality Accident Alarm Systems

    SciTech Connect

    Miller, Thomas Martin; Reynolds, Kevin H.

    2011-01-01

    In October 2010 a series of benchmark experiments was conducted at the Commissariat a Energie Atomique et aux Energies Alternatives (CEA) Valduc SILENE [1] facility. These experiments were a joint effort between the US Department of Energy (DOE) and the French CEA. The purpose of these experiments was to create three benchmarks for the verification and validation of radiation transport codes and evaluated nuclear data used in the analysis of criticality accident alarm systems (CAASs). This presentation will discuss the geometric configuration of these experiments and the quantities that were measured and will present some preliminary comparisons between the measured data and calculations. This series consisted of three single-pulsed experiments with the SILENE reactor. During the first experiment the reactor was bare (unshielded), but during the second and third experiments it was shielded by lead and polyethylene, respectively. During each experiment several neutron activation foils and thermoluminescent dosimeters (TLDs) were placed around the reactor, and some of these detectors were themselves shielded from the reactor by high-density magnetite and barite concrete, standard concrete, and/or BoroBond. All the concrete was provided by CEA Saclay, and the BoroBond was provided by Y-12 National Security Complex. Figure 1 is a picture of the SILENE reactor cell configured for pulse 1. Also included in these experiments were measurements of the neutron and photon spectra with two BICRON BC-501A liquid scintillators. These two detectors were provided and operated by CEA Valduc. They were set up just outside the SILENE reactor cell with additional lead shielding to prevent the detectors from being saturated. The final detectors involved in the experiments were two different types of CAAS detectors. The Babcock International Group provided three CIDAS CAAS detectors, which measured photon dose and dose rate with a Geiger-Mueller tube. CIDAS detectors are currently in

  15. Review of operating experience at the Los Alamos Plutonium Electrorefining Facility, 1963-1977

    SciTech Connect

    Mullins, L.J.; Morgan, A.N.

    1981-12-01

    This report reviews the operation of the Los Alamos Plutonium Electrorefining Plant at Technical Area 21 for the period 1964 through 1977. During that period, approximately 1568 kg of plutonium metal, > 99.95% pure, was produced in 653 runs from 1930 kg of metal fabrication scrap, 99% pure. General considerations of the electrorefining process and facility operation and recommendations for further improvement of the process are discussed.

  16. Scientific Objectives of the Critical Viscosity Experiment

    NASA Technical Reports Server (NTRS)

    Berg, R. F.; Moldover, M. R.

    1993-01-01

    In microgravity, the Critical Viscosity Experiment will measure the viscosity of xenon 15 times closer to the critical point than is possible on earth. The results are expected to include the first direct observation of the predicted power-law divergence of viscosity in a pure fluid and they will test calculations of the value of the exponent associated with the divergence. The results, when combined with Zeno's decay-rate data, will strengthen the test of mode coupling theory. Without microgravity viscosity data, the Zeno test will require an extrapolation of existing 1-g viscosity data by as much as factor of 100 in reduced temperature. By necessity, the extrapolation would use an incompletely verified theory of viscosity crossover. With the microgravity viscosity data, the reliance on crossover models will be negligible allowing a more reliable extrapolation. During the past year, new theoretical calculations for the viscosity exponent finally achieved consistency with the best experimental data for pure fluids. This report gives the justification for the proposed microgravity Critical Viscosity Experiment in this new context. This report also combines for the first time the best available light scattering data with our recent viscosity data to demonstrate the current status of tests of mode coupling theory.

  17. Critical point wetting drop tower experiment

    NASA Technical Reports Server (NTRS)

    Kaukler, William F.

    1990-01-01

    The 100 m Drop Tower at NASA-Marshall was used to provide the step change in acceleration from 1.0 to 0.0005 g. An inter-fluid meniscus oscillates vertically within a cylindrical container when suddenly released from earth's gravity and taken into a microgravity environment. Oscillations damp out from energy dissipative mechanisms such as viscosity and interfacial friction. Damping of the oscillations by the later mechanism is affected by the nature of the interfacial junction between the fluid-fluid interface and the container wall. In earlier stages of the project, the meniscus shape which developed during microgravity conditions was applied to evaluations of wetting phenomena near the critical temperature. Variations in equilibrium contact angle against the container wall were expected to occur under critical wetting conditions. However, it became apparent that the meaningful phenomenon was the damping of interfacial oscillations. This latter concept makes up the bulk of this report. Perfluoromethyl cyclohexane and isopropanol in glass were the materials used for the experiment. The wetting condition of the fluids against the wall changes at the critical wetting transition temperature. This change in wetting causes a change in the damping characteristics of the interfacial excursions during oscillation and no measurable change in contact angle. The effect of contact line friction measured above and below the wetting transition temperature was to increase the period of vertical oscillation for the vapor-liquid interface when below the wetting transition temperature.

  18. The Zeus Copper/Uranium Critical Experiment at NCERC

    SciTech Connect

    Sanchez, Rene G.; Hayes, David K.; Bounds, John Alan; Jackman, Kevin R.; Goda, Joetta M.

    2012-06-15

    A critical experiment was performed to provide nuclear data in a non-thermal neutron spectrum and to reestablish experimental capability relevant to Stockpile Stewardship and Technical Nuclear Forensic programs. Irradiation foils were placed at specific locations in the Zeus all oralloy critical experiment to obtain fission ratios. These ratios were compared with others from other critical assemblies to assess the degree of softness in the neutron spectrum. This critical experiment was performed at the National Criticality Experiments Research Center (NCERC) in Nevada.

  19. A magnetospheric critical velocity experiment - Particle results

    NASA Technical Reports Server (NTRS)

    Torbert, R. B.; Newell, P. T.

    1986-01-01

    In March of 1983, a barium injection sounding rocket experiment (The Star of Lima) was conducted to investigate Alfven's critical ionization velocity (CIV) hypothesis in space. Included in the instrumented payload was a particle detection experiment consisting of five retarding potential analyzers. Despite conditions that appeared to be optimal for the critical velocity effect, the particle data, in agreement with optical observations, indicates that a fractional ionization of only approximately .0005 was observed, indicating that the conditions required for the effect to occur are still not well understood. However many of the required phenomena associated with the CIV effect were observed; in particular a superthermal electron population was formed at the expense of ion drift kinetic energy in the presence of intense electrostatic waves near the lower hybrid frequency. The amount of ionization produced is plausibly consistent with the observed electron flux, but could also be accounted for by residual solar UV at the injection point. It is shown based on the data set that one obvious explanation for the low ionization efficiency, namely that the ionizing superthermal electrons may rapidly escape along field lines, can be ruled out.

  20. Energy supply and environmental issues: The Los Alamos National Laboratory experience in regional and international programs

    SciTech Connect

    Goff, S.J.

    1995-12-31

    The Los Alamos National Laboratory, operated by the University of California, encompasses more than forty-three square miles of mesas and canyons in northern New Mexico. A Department of Energy national laboratory, Los Alamos is one of the largest multidisciplinary, multiprogram laboratories in the world. Our mission, to apply science and engineering capabilities to problems of national security, has expanded to include a broad array of programs. We conduct extensive research in energy, nuclear safeguards and security, biomedical science, computational science, environmental protection and cleanup, materials science, and other basic sciences. The Energy Technology Programs Office is responsible for overseeing and developing programs in three strategic areas: energy systems and the environment, transportation and infrastructure, and integrated chemicals and materials processing. Our programs focus on developing reliable, economic and environmentally sound technologies that can help ensure an adequate supply of energy for the nation. To meet these needs, we are involved in programs that range from new and enhanced oil recovery technologies and tapping renewable energy sources, through efforts in industrial processes, electric power systems, clean coal technologies, civilian radioactive waste, high temperature superconductivity, to studying the environmental effects of energy use.

  1. Cleanup of a Department of Energy Nonreactor Nuclear Facility: Experience at the Los Alamos National Laboratory High Pressure Tritium Laboratory

    SciTech Connect

    Horak, H.L.

    1995-02-01

    On October 25, 1990, Los Alamos National Laboratory (LANL) ceased programmatic operations at the High Pressure Tritium Laboratory (HPTL). Since that time, LANL has been preparing the facility for transfer into the Department of Energy`s (DOE`s) Decontamination and Decommissioning Program. LANL staff now has considerable operational experience with the cleanup of a 40-year-old facility used exclusively to conduct experiments in the use of tritium, the radioactive isotope of hydrogen. Tritium and its compounds have permeated the HPTL structure and equipment, have affected operations and procedures, and now dominate efforts at cleanup and disposal. At the time of shutdown, the HPTL still had a tritium inventory of over 100 grams in a variety of forms and containers.

  2. Critical experiment with uranium diluted with concrete and polyethylene

    SciTech Connect

    Sanchez, R.; Loaiza, D.; Kimpland, R.

    2006-07-01

    An experiment has been performed combining highly enriched uranium, a hydrogenous moderator (polyethylene), and concrete. The purpose of the experiment was to provide additional criticality data that can be used to verify and validate criticality safety evaluations in support of the decommissioning of nuclear facilities throughout the Dept. of Energy complex. In this experiment, criticality was observed as a function time due to the curing and drying processes that occurred in the concrete. (authors)

  3. Providing Nuclear Criticality Safety Analysis Education through Benchmark Experiment Evaluation

    SciTech Connect

    John D. Bess; J. Blair Briggs; David W. Nigg

    2009-11-01

    One of the challenges that today's new workforce of nuclear criticality safety engineers face is the opportunity to provide assessment of nuclear systems and establish safety guidelines without having received significant experience or hands-on training prior to graduation. Participation in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and/or the International Reactor Physics Experiment Evaluation Project (IRPhEP) provides students and young professionals the opportunity to gain experience and enhance critical engineering skills.

  4. The impact and applicability of critical experiment evaluations

    SciTech Connect

    Brewer, R.

    1997-06-01

    This paper very briefly describes a project to evaluate previously performed critical experiments. The evaluation is intended for use by criticality safety engineers to verify calculations, and may also be used to identify data which need further investigation. The evaluation process is briefly outlined; the accepted benchmark critical experiments will be used as a standard for verification and validation. The end result of the project will be a comprehensive reference document.

  5. Summary Report of Laboratory Critical Experiment Analyses Performed for the Disposal Criticality Analysis Methodology

    SciTech Connect

    J. Scaglione

    1999-09-09

    This report, ''Summary Report of Laboratory Critical Experiment Analyses Performed for the Disposal Criticality Analysis Methodology'', contains a summary of the laboratory critical experiment (LCE) analyses used to support the validation of the disposal criticality analysis methodology. The objective of this report is to present a summary of the LCE analyses' results. These results demonstrate the ability of MCNP to accurately predict the critical multiplication factor (keff) for fuel with different configurations. Results from the LCE evaluations will support the development and validation of the criticality models used in the disposal criticality analysis methodology. These models and their validation have been discussed in the ''Disposal Criticality Analysis Methodology Topical Report'' (CRWMS M&O 1998a).

  6. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory's Source Region Program

    SciTech Connect

    Fitzgerald, T.J.; Carlos, R.C.; Argo, P.E.

    1993-01-21

    As part of the integrated verification experiment (IVE), we deployed a network of hf ionospheric sounders to detect the effects of acoustic waves generated by surface ground motion following underground nuclear tests at the Nevada Test Site. The network sampled up to four geographic locations in the ionosphere from almost directly overhead of the surface ground zero out to a horizontal range of 60 km. We present sample results for four of the IVEs: Misty Echo, Texarkana, Mineral Quarry, and Bexar.

  7. Critical Friends Groups: Learning Experiences for Teachers

    ERIC Educational Resources Information Center

    Cox, Ernie

    2010-01-01

    How can school librarians know about other teachers' professional development experiences? School librarians need time to talk with fellow teachers about the wide range of issues and challenges present in schools. A collaborative mission gives precious time to create learning opportunities for students; but does it give enough time for reflective…

  8. Los Alamos Science: Number 23, 1995. Radiation protection and the human radiation experiments

    SciTech Connect

    Cooper, N.G.

    1995-12-31

    There are a variety of myths and misconceptions about the ionizing radiation that surrounds and penetrates us all. Dispel a few of these by taking a leisurely tour of radiation and its properties, of the natural and man-made sources of ionizing radiation, and of the way doses are calculated. By damaging DNA and inducing genetic mutations, ionizing radiation can potentially initiate a cell on the road to cancer. The authors review what is currently known about regulation of cellular reproduction, DNA damage and repair, cellular defense mechanisms, and the specific cancer-causing genes that are susceptible to ionizing radiation. A rapid survey of the data on radiation effects in humans shows that high radiation doses increase the risk of cancer, whereas the effects of low doses are very difficult to detect. The hypothetical risks at low doses, which are estimated from the atomic-bomb survivors, are compared to the low-dose data so that the reader can assess the present level of uncertainty. As part of the openness initiative, ten individuals who have worked with plutonium during various periods in the Laboratory`s history were asked to share their experiences including their accidental intakes. The history and prognosis of people who have had plutonium exposures is discussed by the Laboratory`s leading epidemiologist.

  9. Fiber Bragg grating sensing of detonation and shock experiments at Los Alamos National Laboratory

    NASA Astrophysics Data System (ADS)

    Rodriguez, G.; Sandberg, R. L.; Jackson, S. I.; Dattelbaum, D. M.; Vincent, S. W.; McCulloch, Q.; Martinez, R. M.; Gilbertson, S. M.; Udd, E.

    2013-05-01

    An all optical-fiber-based approach to measuring high explosive detonation front position and velocity is described. By measuring total light return using an incoherent light source reflected from a fiber Bragg grating sensor in contact with the explosive, dynamic mapping of the detonation front position and velocity versus time is obtained. We demonstrate two calibration procedures and provide several examples of detonation front measurements: PBX 9502 cylindrical rate stick, radial detonation front in PBX 9501, and PBX 9501 detonation along a curved meridian line. In the cylindrical rate stick measurement, excellent agreement with complementary diagnostics (electrical pins and streak camera imaging) is achieved, demonstrating accuracy in the detonation front velocity to below the 0.3% level when compared to the results from the pin data. In a similar approach, we use embedded fiber grating sensors for dynamic pressure measurements to test the feasibility of these sensors for high pressure shock wave research in gas gun driven flyer plate impact experiments. By applying well-controlled steady shock wave pressure profiles to soft materials such as PMMA, we study the dynamic pressure response of embedded fiber Bragg gratings to extract pressure amplitude of the shock wave. Comparison of the fiber sensor results is then made with traditional methods (velocimetry and electro-magnetic particle velocity gauges) to gauge the accuracy of the approach.

  10. Implementing NICU critical thinking programs: one unit's experience.

    PubMed

    Zimmerman, Denise; Pilcher, Jobeth

    2008-01-01

    Critical thinking is the hallmark of today's nursing practice environment. Nowhere is this more critical than in the high-tech environment of the NICU. Despite the importance of critical thinking in nursing practice, there is limited information on the process of teaching new NICU nurses to think critically. Based on the principles of adult education, orientation and continuing education for NICU nurses should be goal directed, build on the learner's prior experience, and build in opportunities for active participation, reflection, and experiential learning. This article reviews the principles of adult education and their application to the process of teaching critical thinking in the NICU. One unit's experience of critical thinking education is used to provide concrete examples of how NICU education can be transformed from a traditional didactic methodology to a more dynamic experiential approach. PMID:18697653

  11. Deconstructing Global Markets through Critical Performative Experiences in Puerto Rico

    ERIC Educational Resources Information Center

    Medina, Carmen Liliana; Weltsek, Gustave J.

    2013-01-01

    Critical Performative Pedagogies, the idea that "The nature of drama as a once removed creative experience turns non-critical implicit classroom identity formation into explicit identity performance as it asks participants to actively reflect upon how identity is created and engaged within fictional social interactions." (Weltsek and…

  12. Using Language Experience to ALERT Pupils' Critical Thinking Skills.

    ERIC Educational Resources Information Center

    Allen, Elizabeth Godwin; And Others

    1988-01-01

    Describes the "ALERT" procedure, whereby teachers may combine the language experience approach with the use of radio, television, newspaper, and magazine advertisements in a strategy that is useful for developing critical thinking skills, even in very young students. (ARH)

  13. Weightless experiments to probe universality of fluid critical behavior.

    PubMed

    Lecoutre, C; Guillaument, R; Marre, S; Garrabos, Y; Beysens, D; Hahn, I

    2015-06-01

    Near the critical point of fluids, critical opalescence results in light attenuation, or turbidity increase, that can be used to probe the universality of critical behavior. Turbidity measurements in SF6 under weightlessness conditions on board the International Space Station are performed to appraise such behavior in terms of both temperature and density distances from the critical point. Data are obtained in a temperature range, far (1 K) from and extremely close (a few μK) to the phase transition, unattainable from previous experiments on Earth. Data are analyzed with renormalization-group matching classical-to-critical crossover models of the universal equation of state. It results that the data in the unexplored region, which is a minute deviant from the critical density value, still show adverse effects for testing the true asymptotic nature of the critical point phenomena. PMID:26172640

  14. Weightless experiments to probe universality of fluid critical behavior

    NASA Astrophysics Data System (ADS)

    Lecoutre, C.; Guillaument, R.; Marre, S.; Garrabos, Y.; Beysens, D.; Hahn, I.

    2015-06-01

    Near the critical point of fluids, critical opalescence results in light attenuation, or turbidity increase, that can be used to probe the universality of critical behavior. Turbidity measurements in SF6 under weightlessness conditions on board the International Space Station are performed to appraise such behavior in terms of both temperature and density distances from the critical point. Data are obtained in a temperature range, far (1 K) from and extremely close (a few μ K ) to the phase transition, unattainable from previous experiments on Earth. Data are analyzed with renormalization-group matching classical-to-critical crossover models of the universal equation of state. It results that the data in the unexplored region, which is a minute deviant from the critical density value, still show adverse effects for testing the true asymptotic nature of the critical point phenomena.

  15. Experience With the SCALE Criticality Safety Cross Section Libraries

    SciTech Connect

    Bowman, S.M.

    2000-08-21

    This report provides detailed information on the SCALE criticality safety cross-section libraries. Areas covered include the origins of the libraries, the data on which they are based, how they were generated, past experience and validations, and performance comparisons with measured critical experiments and numerical benchmarks. The performance of the SCALE criticality safety cross-section libraries on various types of fissile systems are examined in detail. Most of the performance areas are demonstrated by examining the performance of the libraries vs critical experiments to show general trends and weaknesses. In areas where directly applicable critical experiments do not exist, performance is examined based on the general knowledge of the strengths and weaknesses of the cross sections. In this case, the experience in the use of the cross sections and comparisons with the results of other libraries on the same systems are relied on for establishing acceptability of application of a particular SCALE library to a particular fissile system. This report should aid in establishing when a SCALE cross-section library would be expected to perform acceptably and where there are known or suspected deficiencies that would cause the calculations to be less reliable. To determine the acceptability of a library for a particular application, the calculational bias of the library should be established by directly applicable critical experiments.

  16. Recent Research with the Detector for Advanced Neutron Capture Experiments (dance) at the LOS Alamos Neutron Science Center

    NASA Astrophysics Data System (ADS)

    Ullmann, J. L.

    2014-09-01

    The DANCE detector at Los Alamos is a 160 element, nearly 4π BaF2 detector array designed to make measurements of neutron capture on rare or radioactive nuclides. It has also been used to make measurements of gamma-ray multiplicity following capture and gamma-ray output from fission. Several examples of measurements are briefly discussed.

  17. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory`s Source Region Program. Appendix B: Surface ground motion

    SciTech Connect

    Weaver, T.A.; Baker, D.F.; Edwards, C.L.; Freeman, S.H.

    1993-10-01

    Surface ground motion was recorded for many of the Integrated Verification Experiments using standard 10-, 25- and 100-g accelerometers, force-balanced accelerometers and, for some events, using golf balls and 0.39-cm steel balls as surface inertial gauges (SIGs). This report contains the semi-processed acceleration, velocity, and displacement data for the accelerometers fielded and the individual observations for the SIG experiments. Most acceleration, velocity, and displacement records have had calibrations applied and have been deramped, offset corrected, and deglitched but are otherwise unfiltered or processed from their original records. Digital data for all of these records are stored at Los Alamos National Laboratory.

  18. Review of critical velocity experiments in the ionosphere

    NASA Technical Reports Server (NTRS)

    Torbert, R. B.

    1990-01-01

    Observations relevant to Alfven's Critical Velocity Effect, of the several shaped-charge releases in the ionosphere are compared with three generations of a macroscopic model of these releases. Good agreement is found with experiments which have reported a low ion yield, but major discrepancies remain with the Porcupine experiment which has the largest yield yet reported.

  19. Review of critical velocity experiments in the ionosphere

    NASA Astrophysics Data System (ADS)

    Torbert, R. B.

    Observations relevant to Alfven's Critical Velocity Effect, of the several shaped-charge releases in the ionosphere are compared with three generations of a macroscopic model of these releases. Good agreement is found with experiments which have reported a low ion yield, but major discrepancies remain with the Porcupine experiment which has the largest yield yet reported.

  20. An Undergraduate Journal Club Experience: A Lesson in Critical Thinking

    ERIC Educational Resources Information Center

    Roberts, Jennifer

    2009-01-01

    In an effort to better prepare undergraduate students to read and critically evaluate scientific literature, a journal club experience was introduced into a university's bachelor of science curriculum. As a result of this experience, students have been found to be more thoughtful, poised, and articulate presenters, a fact that they, the students,…

  1. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory`s Source Region Program. Appendix C, Infrasonic measurements of IVE events: Los Alamos Source Region Program

    SciTech Connect

    Whitaker, R.W.; Noel, S.D.

    1992-12-01

    The summary report by Tom Weaver gives the overall background for the series of IVE (Integrated Verification Experiment) experiments including information on the full set of measurements made. This appendix presents details of the infrasound data for the and discusses certain aspects of a few special experiments. Prior to FY90, the emphasis of the Infrasound Program was on underground nuclear test (UGT) detection and yield estimation. During this time the Infrasound Program was a separate program at Los Alamos, and it was suggested to DOE/OAC that a regional infrasound network be established around NTS. The IVE experiments took place in a time frame that allowed simultaneous testing of possible network sites and examination of propagation in different directions. Whenever possible, infrasound stations were combined with seismic stations so that a large number could be efficiently fielded. The regional infrasound network was not pursued by DOE, as world events began to change the direction of verification toward non-proliferation. Starting in FY90 the infrasound activity became part of the Source Region Program which has a goal of understanding how energy is transported from the UGT to a variety of measurement locations.

  2. Critical experiments analysis by ABBN-90 constant system

    SciTech Connect

    Tsiboulia, A.; Nikolaev, M.N.; Golubev, V.

    1997-06-01

    The ABBN-90 is a new version of the well-known Russian group-constant system ABBN. Included constants were calculated based on files of evaluated nuclear data from the BROND-2, ENDF/B-VI, and JENDL-3 libraries. The ABBN-90 is intended for the calculation of different types of nuclear reactors and radiation shielding. Calculations of criticality safety and reactivity accidents are also provided by using this constant set. Validation of the ABBN-90 set was made by using a computerized bank of evaluated critical experiments. This bank includes the results of experiments conducted in Russia and abroad of compact spherical assemblies with different reflectors, fast critical assemblies, and fuel/water-solution criticalities. This report presents the results of the calculational analysis of the whole collection of critical experiments. All calculations were produced with the ABBN-90 group-constant system. Revealed discrepancies between experimental and calculational results and their possible reasons are discussed. The codes and archives INDECS system is also described. This system includes three computerized banks: LEMEX, which consists of evaluated experiments and their calculational results; LSENS, which consists of sensitivity coefficients; and LUND, which consists of group-constant covariance matrices. The INDECS system permits us to estimate the accuracy of neutronics calculations. A discussion of the reliability of such estimations is finally presented. 16 figs.

  3. Validation of KENO V.a Comparison with Critical Experiments

    SciTech Connect

    Jordan, W.C.

    1999-01-01

    Section 1 of this report documents the validation of KENO V.a against 258 critical experiments. Experiments considered were primarily high or low enriched uranium systems. The results indicate that the KENO V.a Monte Carlo Criticality Program accurately calculates a broad range of critical experiments. A substantial number of the calculations showed a positive or negative bias in excess of 1 1/2% in k-effective (k{sub eff}). Classes of criticals which show a bias include 3% enriched green blocks, highly enriched uranyl fluoride slab arrays, and highly enriched uranyl nitrate arrays. If these biases are properly taken into account, the KENO V.a code can be used with confidence for the design and criticality safety analysis of uranium-containing systems. Section 2 of this report documents the results of investigation into the cause of the bias observed in Sect. 1. The results of this study indicate that the bias seen in Sect. 1 is caused by code bias, cross-section bias, reporting bias, and modeling bias. There is evidence that many of the experiments used in this validation and in previous validations are not adequately documented. The uncertainty in the experimental parameters overshadows bias caused by the code and cross sections and prohibits code validation to better than about 1% in k{sub eff}.

  4. A Geophysical Flow Experiment in a Compressible Critical Fluid

    NASA Technical Reports Server (NTRS)

    Hegseth, John; Garcia, Laudelino

    1996-01-01

    The first objective of this experiment is to build an experimental system in which, in analogy to a geophysical system, a compressible fluid in a spherical annulus becomes radially stratified in density through an A.C. electric field. When this density gradient is demonstrated, the system will be augmented so that the fluid can be driven by heating and rotation and tested in preparation for a microgravity experiment. This apparatus consists of a spherical capacitor filled with critical fluid in a temperature controlled environment. To make the fluid critical, the apparatus will be operated near the critical pressure, critical density, and critical temperature of the fluid. This will result in a highly compressible fluid because of the properties of the fluid near its critical point. A high voltage A.C. source applied across the capacitor will create a spherically symmetric central force because of the dielectric properties of the fluid in an electric field gradient. This central force will induce a spherically symmetric density gradient that is analogous to a geophysical fluid system. To generate such a density gradient the system must be small (approx. 1 inch diameter). This small cell will also be capable of driving the critical fluid by heating and rotation. Since a spherically symmetric density gradient can only be made in microgravity, another small cell, of the same geometry, will be built that uses incompressible fluid. The driving of the fluid by rotation and heating in these small cells will be developed. The resulting instabilities from the driving in these two systems will then be studied. The second objective is to study the pattern forming instabilities (bifurcations) resulting from the well controlled experimental conditions in the critical fluid cell. This experiment will come close to producing conditions that are geophysically similar and will be studied as the driving parameters are changed.

  5. Criticality experiments and benchmarks for cross section evaluation: the neptunium case

    NASA Astrophysics Data System (ADS)

    Leong, L. S.; Tassan-Got, L.; Audouin, L.; Paradela, C.; Wilson, J. N.; Tarrio, D.; Berthier, B.; Duran, I.; Le Naour, C.; Stéphan, C.

    2013-03-01

    The 237Np neutron-induced fission cross section has been recently measured in a large energy range (from eV to GeV) at the n_TOF facility at CERN. When compared to previous measurement the n_TOF fission cross section appears to be higher by 5-7% beyond the fission threshold. To check the relevance of n_TOF data, we apply a criticality experiment performed at Los Alamos with a 6 kg sphere of 237Np, surrounded by enriched uranium 235U so as to approach criticality with fast neutrons. The multiplication factor ke f f of the calculation is in better agreement with the experiment (the deviation of 750 pcm is reduced to 250 pcm) when we replace the ENDF/B-VII.0 evaluation of the 237Np fission cross section by the n_TOF data. We also explore the hypothesis of deficiencies of the inelastic cross section in 235U which has been invoked by some authors to explain the deviation of 750 pcm. With compare to inelastic large distortion calculation, it is incompatible with existing measurements. Also we show that the v of 237Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n_TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237Np.

  6. Validation of Cross Sections with Criticality Experiment and Reaction Rates: the Neptunium Case

    NASA Astrophysics Data System (ADS)

    Leong, L. S.; Tassan-Got, L.; Audouin, L.; Berthier, B.; Le Naour, C.; Stéphan, C.; Paradela, C.; Tarrío, D.; Duran, I.

    2014-04-01

    The 237Np neutron-induced fission cross section has been recently measured in a large energy range (from eV to GeV) at the n_TOF facility at CERN. When compared to previous measurements the n_TOF fission cross section appears to be higher by 5-7% beyond the fission threshold. To check the relevance of the n_TOF data, we considered a criticality experiment performed at Los Alamos with a 6 kg sphere of 237Np, surrounded by uranium highly enriched in 235U so as to approach criticality with fast neutrons. The multiplication factor keff of the calculation is in better agreement with the experiment when we replace the ENDF/B-VII.0 evaluation of the 237Np fission cross section by the n_TOF data. We also explored the hypothesis of deficiencies of the inelastic cross section in 235U which has been invoked by some authors to explain the deviation of 750 pcm. The large modification needed to reduce the deviation seems to be incompatible with existing inelastic cross section measurements. Also we show that the νbar of 237Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n_TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237Np.

  7. Postanalysis of the CNPS (Compact Nuclear Power Source) critical experiment

    NASA Astrophysics Data System (ADS)

    Palmer, R. G.

    The Compact Nuclear Power Source (CNPS) was designed to produce electric power for remote sites where fuel logistics and costs would justify a remotely sited nuclear power plant. Since the reactor was of novel design with no appropriate benchmarks, a series of critical experiments was carried out at LANL. This paper describes the methodology and reports the results of the postanalysis that was performed on the critical experiments, which included several distinct critical configurations, the measurement of the isothermal temperature coefficient of reactivity and various material worths. Comparisons with measurements indicate that current methods and cross sections are adequate for calculating at least the beginning of life conditions in low enriched U-235-graphite cores.

  8. Postanalysis of the CNPS (Compact Nuclear Power Source) critical experiment

    SciTech Connect

    Palmer, R.G.

    1988-01-01

    The Compact Nuclear Power Source (CNPS) was designed to produce electric power for remote sites where fuel logistics and costs would justify a remotely sited nuclear power plant. Since the reactor was of novel design with no appropriate benchmarks, a series of critical experiments was carried out at LANL. This paper describes the methodology and reports the results of the postanalysis that was performed on the critical experiments, which included several distinct critical configurations, the measurement of the isothermal temperature coefficient of reactivity and various material worths. Comparisons with measurements indicate that current methods and cross sections are adequate for calculating at least the beginning of life conditions in low enriched /sup 235/U-graphite cores. 7 refs., 4 figs., 4 tabs.

  9. The Nuclear Criticality Information System's project to archive unpublished critical experiment data

    SciTech Connect

    Koponen, B.L. ); Clayton, E.D.; Doherty, A.L. )

    1991-07-01

    Critical experiment facilities produced a large amount of important data during the past forty-five years. However, much useful data remains unpublished. The unpublished material exists in the form of experimenters' logbooks, notes, photographs, material descriptions, etc. These data could be important for computer code validation, understanding the physics of criticality, facility design, or for setting process limits. In the past, criticality specialists have been able to obtain unpublished details by direct contact with the experimenters. Obviously, this will not be possible indefinitely. Most of the US critical experiment facilities are now closed, the experimenters are moving the other jobs, retiring, or otherwise becoming unavailable for this informal assistance. The closure of the facilities and the loss of personnel is likely to lead to the loss of the facility records unless an effort is made to assure that the records are preserved. It has been recognized for some time that the unpublished records of critical experiment facilities comprise a valuable resource, thus the Nuclear Criticality Information System (NCIS) is working to insure that the records are preserved and made available via NCIS. As a first step in the archiving project, we identified criteria to help judge which series of experiments should be considered for archiving. Data that are used for validating calculations or the basis for subcritical limits in standards, handbooks, and guides are of particular importance. In this paper we will discuss the criteria for archiving, the priority list of experiments for archiving, and progress in developing an NCIS image database using current CD-ROM technology.

  10. The Nuclear Criticality Information System`s project to archive unpublished critical experiment data

    SciTech Connect

    Koponen, B.L.; Clayton, E.D.; Doherty, A.L.

    1991-07-01

    Critical experiment facilities produced a large amount of important data during the past forty-five years. However, much useful data remains unpublished. The unpublished material exists in the form of experimenters` logbooks, notes, photographs, material descriptions, etc. These data could be important for computer code validation, understanding the physics of criticality, facility design, or for setting process limits. In the past, criticality specialists have been able to obtain unpublished details by direct contact with the experimenters. Obviously, this will not be possible indefinitely. Most of the US critical experiment facilities are now closed, the experimenters are moving the other jobs, retiring, or otherwise becoming unavailable for this informal assistance. The closure of the facilities and the loss of personnel is likely to lead to the loss of the facility records unless an effort is made to assure that the records are preserved. It has been recognized for some time that the unpublished records of critical experiment facilities comprise a valuable resource, thus the Nuclear Criticality Information System (NCIS) is working to insure that the records are preserved and made available via NCIS. As a first step in the archiving project, we identified criteria to help judge which series of experiments should be considered for archiving. Data that are used for validating calculations or the basis for subcritical limits in standards, handbooks, and guides are of particular importance. In this paper we will discuss the criteria for archiving, the priority list of experiments for archiving, and progress in developing an NCIS image database using current CD-ROM technology.

  11. Critical Reflections: Interpretation and Analysis of Japanese Women's Settlement Experiences

    ERIC Educational Resources Information Center

    Takeda, Atsushi

    2012-01-01

    In this paper, I discuss how I came to call into question the way in which I interpreted interview data in my dissertation, which investigated the migration and settlement experience of Japanese women who are married to Australian men and reside in Australia. Through critical reflections, I realized the way in which the positionality of…

  12. Analysis of Fundamental NIST Sphere Experiments Related to Criticality Safety

    SciTech Connect

    Kim, Soon S.

    2007-06-01

    A series of neutron transport experiments was performed in 1989 and 1990 at NIST (National Institute of Standards and Technology) using a spherical stainless steel container and fission chambers. These experiments were performed to help understand errors observed in criticality calculations for arrays of individually subcritical components, particularly solution arrays [1-3]. They were supported by the U.S. Department of Energy, Environment and Health, Nuclear Criticality Technology and Safety Project. The intent was to evaluate the possibility that the criticality prediction errors stem from errors in the calculation of neutron leakage from individual components of the array. Thus, the explicit product of the experiments was the measurement of the leakage flux, as characterized by various Cd-shielded and unshielded fission rates. Because the various fission rates have different neutron-energy sensitivities, collectively they give an indication of the energy dependence of the leakage flux. Leakage and moderation were varied systematically through the use of different diameter spheres, with and without water. Some of these experiments with bare fission chambers have been evaluated by the International Criticality Safety Benchmark Evaluation Project (ICSBEP)[4].

  13. Implementation and Critical Assessment of the Flipped Classroom Experience

    ERIC Educational Resources Information Center

    Scheg, Abigail G., Ed.

    2015-01-01

    In the past decade, traditional classroom teaching models have been transformed in order to better promote active learning and learner engagement. "Implementation and Critical Assessment of the Flipped Classroom Experience" seeks to capture the momentum of non-traditional teaching methods and provide a necessary resource for individuals…

  14. TRIGA Mark II Criticality Benchmark Experiment with Burned Fuel

    SciTech Connect

    Persic, Andreja; Ravnik, Matjaz; Zagar, Tomaz

    2000-12-15

    The experimental results of criticality benchmark experiments performed at the Jozef Stefan Institute TRIGA Mark II reactor are presented. The experiments were performed with partly burned fuel in two compact and uniform core configurations in the same arrangements as were used in the fresh fuel criticality benchmark experiment performed in 1991. In the experiments, both core configurations contained only 12 wt% U-ZrH fuel with 20% enriched uranium. The first experimental core contained 43 fuel elements with average burnup of 1.22 MWd or 2.8% {sup 235}U burned. The last experimental core configuration was composed of 48 fuel elements with average burnup of 1.15 MWd or 2.6% {sup 235}U burned. The experimental determination of k{sub eff} for both core configurations, one subcritical and one critical, are presented. Burnup for all fuel elements was calculated in two-dimensional four-group diffusion approximation using the TRIGLAV code. The burnup of several fuel elements was measured also by the reactivity method.

  15. The National Criticality Experiments Research Center at the Device Assembly Facility, Nevada National Security Site: Status and Capabilities, Summary Report

    SciTech Connect

    S. Bragg-Sitton; J. Bess; J. Werner

    2011-09-01

    The National Criticality Experiments Research Center (NCERC) was officially opened on August 29, 2011. Located within the Device Assembly Facility (DAF) at the Nevada National Security Site (NNSS), the NCERC has become a consolidation facility within the United States for critical configuration testing, particularly those involving highly enriched uranium (HEU). The DAF is a Department of Energy (DOE) owned facility that is operated by the National Nuclear Security Agency/Nevada Site Office (NNSA/NSO). User laboratories include the Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL). Personnel bring their home lab qualifications and procedures with them to the DAF, such that non-site specific training need not be repeated to conduct work at DAF. The NNSS Management and Operating contractor is National Security Technologies, LLC (NSTec) and the NNSS Safeguards and Security contractor is Wackenhut Services. The complete report provides an overview and status of the available laboratories and test bays at NCERC, available test materials and test support configurations, and test requirements and limitations for performing sub-critical and critical tests. The current summary provides a brief summary of the facility status and the method by which experiments may be introduced to NCERC.

  16. Beryllium reflected cavity reactor for UF6 critical experiments

    NASA Technical Reports Server (NTRS)

    Jarvis, G. A.; Bernard, W.; Helmick, H. H.; White, R.

    1975-01-01

    Experiments and theoretical studies are being conducted for NASA on critical assemblies with one-meter diam by one-meter long low-density cores surrounded by a thick beryllium reflector. These assemblies make extensive use of existing nuclear propulsion reactor components, facilities, and instrumentation. Due to excessive porosity in the reflector, the initial critical mass was 19 kg U(93.2). Addition of a 17-cm-thick by 89-cm-diam beryllium flux trap in the cavity reduced the critical mass to 7 kg when all the uranium was in the zone just outside the flux trap. A mockup aluminum UF6 container was placed inside the flux trap and fueled with uranium-graphite elements. Fission distributions and reactivity worths of fuel and structural materials are available. These results will be used to guide the design of a prototype plasma core reactor which will test energy removal by optical radiation.

  17. High-energy density physics at Los Alamos

    NASA Astrophysics Data System (ADS)

    Byrnes, P.

    1993-03-01

    This brochure describes the facilities of the Above Ground Experiments 2 (AGEX 2) and the Inertial Confinement Fusion (ICF) programs at Los Alamo. Combined, these programs represent, an unparalleled capability to address important issues in high-energy density physics that are critical to the future defense, energy, and research needs of the United States. The mission of the AGEX 2 program at Los Alamos is to provide additional experimental opportunities for the nuclear weapons program. For this purpose we have assembled at Los Alamos the broadest array of high-energy density physics facilities of any laboratory in the world. Inertial confinement fusion seeks to achieve thermonuclear burn on a laboratory scale through the implosion of a small quantity of deuterium and tritium fuel to very high pressure and temperature. The Los Alamos ICF program is focused on target physics. With the largest scientific computing center in the world, We can perform calculations of unprecedented sophistication and precision. We field experiments at facilities worldwide--including our own Trident and Mercury lasers--to confirm our understanding and to provide the necessary data base to proceed toward the historic goal of controlled fusion in the laboratory. The ultrahigh magnetic fields produced in our high explosive pulsed-power generators can be used in a wide variety of solid state physics and temperature superconductor studies. The structure and dynamics of planetary atmospheres can be simulated through the compression of gas mixtures.

  18. Significant Learning Experiences in Ecohydrology in the Critical Zone

    NASA Astrophysics Data System (ADS)

    Lohse, K. A.

    2014-12-01

    We are integrating several significant learning experiences into the Reynolds Creek Critical Zone Observatory to engage the public, K-12, undergraduate and graduate students in ecohydrology in the critical zone. This observatory is meant to be a living laboratory for Idaho K-12 and college educators and support curriculum development for soil carbon for science education and centers. A new summer 2 week course in Environmental Field Methods is being developed and implemented to provide active learning experiences in soil and watershed hydrology, plant-water relations and carbon exchange, and soil descriptions. A graduate seminar has been implement to train graduate students in communicating science to the public and developing informal education such as exhibits to enhance active learning. Other educational outreach activities include adventure learning in the watershed by 8th graders from local school districts as well as public exhibits at environmental fairs, science festivals and communiversity events. These education and outreach activities are collectively targeted at engaging the public and new critical mass of graduate students and undergraduates in Critical Zone Science.

  19. Measurement of Critical Contact Angle in a Microgravity Space Experiment

    NASA Technical Reports Server (NTRS)

    Concus, P.; Finn, R.; Weislogel, M.

    1998-01-01

    Mathematical theory predicts that small changes in container shape or in contact angle can give rise to large shifts of liquid in a microgravity environment. This phenomenon was investigated in the Interface Configuration Experiment on board the USMT,2 Space Shuttle flight. The experiment's "double proboscis" containers were designed to strike a balance between conflicting requirements of sizable volume of liquid shift (for ease of observation) and abruptness of the shift (for accurate determination of critical contact angle). The experimental results support the classical concept of macroscopic contact angle and demonstrate the role of hysteresis in impeding orientation toward equilibrium.

  20. Measurement of Critical Contact Angle in a Microgravity Space Experiment

    NASA Technical Reports Server (NTRS)

    Concus, P.; Finn, R.; Weislogel, M.

    1998-01-01

    Mathematical theory predicts that small changes in container shape or in contact angle can give rise to large shifts of liquid in a microgravity environment. This phenomenon was investigated in the Interface Configuration Experiment on board the USML-2 Space Shuttle flight. The experiment's "double proboscis" containers were designed to strike a balance between conflicting requirements of sizable volume of liquid shift (for ease of observation) and abruptness of the shift (for accurate determination of critical contact angle). The experimental results support the classical concept of macroscopic contact angle and demonstrate the role of hysteresis in impeding orientation toward equilibrium.

  1. Parametric analyses of planned flowing uranium hexafluoride critical experiments

    NASA Technical Reports Server (NTRS)

    Rodgers, R. J.; Latham, T. S.

    1976-01-01

    Analytical investigations were conducted to determine preliminary design and operating characteristics of flowing uranium hexafluoride (UF6) gaseous nuclear reactor experiments in which a hybrid core configuration comprised of UF6 gas and a region of solid fuel will be employed. The investigations are part of a planned program to perform a series of experiments of increasing performance, culminating in an approximately 5 MW fissioning uranium plasma experiment. A preliminary design is described for an argon buffer gas confined, UF6 flow loop system for future use in flowing critical experiments. Initial calculations to estimate the operating characteristics of the gaseous fissioning UF6 in a confined flow test at a pressure of 4 atm, indicate temperature increases of approximately 100 and 1000 K in the UF6 may be obtained for total test power levels of 100 kW and 1 MW for test times of 320 and 32 sec, respectively.

  2. Feasibility of performing criticality experiments with spent LWR fuel

    SciTech Connect

    Bierman, S.R.

    1988-02-01

    Criticality experiments can be performed with irradiated LWR fuel under very well defined and controlled conditions to provide data sutiable for verifying calculational models. Two facilities currently exist in which such experiments could be performed. Furthermore, the experiments can be performed in a timely manner and for a relatively reasonable cost. It is expected the cost will be greater than those normally incurred for similar experiments with unirradiated fuel because of the handling problems created by the high radiation fields. Although the cost will of course depend on the scoper of the experimental programs, current estimates indicate the costs will be less or comparable to a similar level of effort in other activities with irradiated fuel (e.g., Dry Rod Consolation Project). 2 figs.

  3. Results from the CACTI experiment: Air-Cerenkov and particle measurements of PeV air showers at Los Alamos

    SciTech Connect

    Paling, S.; Hillas, A.M.; Berley, D.

    1997-07-01

    An array of six wide angle Cerenkov detectors was constructed amongst the scintillator and muon detectors of the CYGNUS II array at Los Alamos National Laboratory to investigate cosmic ray composition in the PeV region through measurements of the shape of Cerenkov lateral distributions. Data were collected during clear, moonless nights over three observing periods in 1995. Estimates of depths of shower maxima determined from the recorded Cerenkov lateral distributions align well with existing results at higher energies and suggest a mixed to heavy composition in the PeV region with no significant variation observed around the knee. The accuracy of composition determination is limited by uncertainties in the expected levels of depth of maximum predicted using different Monte-Carlo shower simulation models.

  4. Critical fluid thermal equilibration experiment (19-IML-1)

    NASA Technical Reports Server (NTRS)

    Wilkinson, R. Allen

    1992-01-01

    Gravity sometimes blocks all experimental techniques of making a desired measurement. Any pure fluid possesses a liquid-vapor critical point. It is defined by a temperature, pressure, and density state in thermodynamics. The critical issue that this experiment attempts to understand is the time it takes for a sample to reach temperature and density equilibrium as the critical point is approached; is it infinity due to mass and thermal diffusion, or do pressure waves speed up energy transport while mass is still under diffusion control. The objectives are to observe: (1) large phase domain homogenization without and with stirring; (2) time evolution of heat and mass after temperature step is applied to a one phase equilibrium sample; (3) phase evolution and configuration upon going two phase from a one phase equilibrium state; (4) effects of stirring on a low g two phase configuration; (5) two phase to one phase healing dynamics starting from a two phase low g configuration; and (6) effects of shuttle acceleration events on spatially and temporally varying compressible critical fluid dynamics.

  5. What’s so critical about Critical Neuroscience? Rethinking experiment, enacting critique

    PubMed Central

    Fitzgerald, Des; Matusall, Svenja; Skewes, Joshua; Roepstorff, Andreas

    2014-01-01

    In the midst of on-going hype about the power and potency of the new brain sciences, scholars within “Critical Neuroscience” have called for a more nuanced and sceptical neuroscientific knowledge-practice. Drawing especially on the Frankfurt School, they urge neuroscientists towards a more critical approach—one that re-inscribes the objects and practices of neuroscientific knowledge within webs of social, cultural, historical and political-economic contingency. This paper is an attempt to open up the black-box of “critique” within Critical Neuroscience itself. Specifically, we argue that limiting enactments of critique to the invocation of context misses the force of what a highly-stylized and tightly-bound neuroscientific experiment can actually do. We show that, within the neuroscientific experiment itself, the world-excluding and context-denying “rules of the game” may also enact critique, in novel and surprising forms, while remaining formally independent of the workings of society, and culture, and history. To demonstrate this possibility, we analyze the Optimally Interacting Minds (OIM) paradigm, a neuroscientific experiment that used classical psychophysical methods to show that, in some situations, people worked better as a collective, and not as individuals—a claim that works precisely against reactionary tendencies that prioritize individual over collective agency, but that was generated and legitimized entirely within the formal, context-denying conventions of neuroscientific experimentation. At the heart of this paper is a claim that it was precisely the rigors and rules of the experimental game that allowed these scientists to enact some surprisingly critical, and even radical, gestures. We conclude by suggesting that, in the midst of large-scale neuroscientific initiatives, it may be “experiment”, and not “context”, that forms the meeting-ground between neuro-biological and socio-political research practices. PMID:24910605

  6. The Los Alamos Space Science Outreach (LASSO) Program

    NASA Astrophysics Data System (ADS)

    Barker, P. L.; Skoug, R. M.; Alexander, R. J.; Thomsen, M. F.; Gary, S. P.

    2002-12-01

    The Los Alamos Space Science Outreach (LASSO) program features summer workshops in which K-14 teachers spend several weeks at LANL learning space science from Los Alamos scientists and developing methods and materials for teaching this science to their students. The program is designed to provide hands-on space science training to teachers as well as assistance in developing lesson plans for use in their classrooms. The program supports an instructional model based on education research and cognitive theory. Students and teachers engage in activities that encourage critical thinking and a constructivist approach to learning. LASSO is run through the Los Alamos Science Education Team (SET). SET personnel have many years of experience in teaching, education research, and science education programs. Their involvement ensures that the teacher workshop program is grounded in sound pedagogical methods and meets current educational standards. Lesson plans focus on current LANL satellite projects to study the solar wind and the Earth's magnetosphere. LASSO is an umbrella program for space science education activities at Los Alamos National Laboratory (LANL) that was created to enhance the science and math interests and skills of students from New Mexico and the nation. The LASSO umbrella allows maximum leveraging of EPO funding from a number of projects (and thus maximum educational benefits to both students and teachers), while providing a format for the expression of the unique science perspective of each project.

  7. Fast Reactor Spent Fuel Processing: Experience and Criticality Safety

    SciTech Connect

    Chad Pope

    2007-05-01

    This paper discusses operational and criticality safety experience associated with the Idaho National Laboratory Fuel Conditioning Facility which uses a pyrometallurgical process to treat spent fast reactor metallic fuel. The process is conducted in an inert atmosphere hot cell. The process starts with chopping metallic fuel elements into a basket. The basket is lowered into molten salt (LiCl-KCl) along with a steel mandrel. Active metal fission products, transuranic metals and sodium metal in the spent fuel undergo chemical oxidation and form chlorides. Voltage is applied between the basket, which serves as an anode, and the mandrel, which serves as a cathode, causing metallic uranium in the spent fuel to undergo electro-chemical oxidation thereby forming uranium chloride. Simultaneously at the cathode, uranium chloride undergoes electro-chemical reduction and deposits uranium metal onto the mandrel. The uranium metal and accompanying entrained salt are placed in a distillation furnace where the uranium melts forming an ingot and the entrained salt boils and subsequently condenses in a separate crucible. The uranium ingots are placed in long term storage. During the ten year operating history, over one hundred criticality safety evaluations were prepared. All criticality safety related limits and controls for the entire process are contained in a single document which required over thirty revisions to accommodate the process changes. Operational implementation of the limits and controls includes use of a near real-time computerized tracking system. The tracking system uses an Oracle database coupled with numerous software applications. The computerized tracking system includes direct fuel handler interaction with every movement of material. Improvements to this system during the ten year history include introduction of web based operator interaction, tracking of moderator materials and the development of a plethora database queries to assist in day to day

  8. Forecast of criticality experiments and experimental programs needed to support nuclear operations in the United States of America: 1994--1999

    SciTech Connect

    Rutherford, D.

    1994-03-01

    This Forecast is generated by the Chair of the Experiment Needs Identification Workgroup (ENIWG), with input from Department of Energy and the nuclear community. One of the current concerns addressed by ENIWG was the Defense Nuclear Facilities Safety Board`s Recommendation 93-2. This Recommendation delineated the need for a critical experimental capability, which includes (1) a program of general-purpose experiments, (2) improving the information base, and (3) ongoing departmental programs. The nuclear community also recognizes the importance of criticality theory, which, as a stepping stone to computational analysis and safety code development, needs to be benchmarked against well-characterized critical experiments. A summary project of the Department`s needs with respect to criticality information includes (1) hands-on training, (2) criticality and nuclear data, (3) detector systems, (4) uranium- and plutonium-based reactors, and (5) accident analysis. The Workgroup has evaluated, prioritized, and categorized each proposed experiment and program. Transportation/Applications is a new category intended to cover the areas of storage, training, emergency response, and standards. This category has the highest number of priority-1 experiments (nine). Facilities capable of performing experiments include the Los Alamos Critical Experiment Facility (LACEF) along with Area V at Sandia National Laboratory. The LACEF continues to house the most significant collection of critical assemblies in the Western Hemisphere. The staff of this facility and Area V are trained and certified, and documentation is current. ENIWG will continue to work with the nuclear community to identify and prioritize experiments because there is an overwhelming need for critical experiments to be performed for basic research and code validation.

  9. Paramedics' experiences and coping strategies when encountering critical incidents.

    PubMed

    Avraham, Nira; Goldblatt, Hadass; Yafe, Eli

    2014-02-01

    Paramedics frequently encounter critical incidents (CIs). Their emotional, cognitive, and behavioral responses to these encounters present them with a variety of difficulties on the way to, during, and after events. The aim of our study was to examine how paramedics working in a large emergency service organization in Israel experienced CIs and the coping strategies they used to deal with these experiences. We interviewed 15 paramedics from this organization. Through data analysis, we revealed two main themes: (1) between connection and detachment and (2) between control and lack of control of the situation. Paramedics, who connected with their feelings regarding the patient and/or the family in different CIs, as well as those who sensed a lack of control, experienced difficult and negative emotions. To achieve detachment, they used a variety of coping strategies. Those who experienced cognitive and functional control of the situation reported a positive and empowering experience. PMID:24495988

  10. The onset of visual experience gates auditory cortex critical periods

    PubMed Central

    Mowery, Todd M.; Kotak, Vibhakar C.; Sanes, Dan H.

    2016-01-01

    Sensory systems influence one another during development and deprivation can lead to cross-modal plasticity. As auditory function begins before vision, we investigate the effect of manipulating visual experience during auditory cortex critical periods (CPs) by assessing the influence of early, normal and delayed eyelid opening on hearing loss-induced changes to membrane and inhibitory synaptic properties. Early eyelid opening closes the auditory cortex CPs precociously and dark rearing prevents this effect. In contrast, delayed eyelid opening extends the auditory cortex CPs by several additional days. The CP for recovery from hearing loss is also closed prematurely by early eyelid opening and extended by delayed eyelid opening. Furthermore, when coupled with transient hearing loss that animals normally fully recover from, very early visual experience leads to inhibitory deficits that persist into adulthood. Finally, we demonstrate a functional projection from the visual to auditory cortex that could mediate these effects. PMID:26786281

  11. Experiments for IFR fuel criticality in ZPPR-21

    SciTech Connect

    Olsen, D N; Smith, D M; Grasseschi, G L; Goin, R W; Steinhauer, J A; Collins, P J; Carpenter, S G

    1991-01-01

    A series of six criticality benchmark cores was built in ZPPR-21 between June and September 1990 to provide data for validating criticality calculations for systems likely to arise in the IFR fuel processing operations. The assemblies were graphite reflected and had core compositions containing different mixtures of Pu/U/Zr fuel. No previous data existed for cores of this type. Analysis of the data was done, in full detail, with an automated input processor using the VIM Monte Carlo code and ENDF/B-V.2 data. Since the validated method of criticality calculations at ANL is the KENO code and data, a second set of calculations, using a simplified model in RZ geometry was made with both VIM and KENO. An RZ model is specified together with geometrical corrections from the VIM calculations. This enables simple calculations to be made and corrections applied within the statistical uncertainty limits. The full description of the experiments is provided to enable calculations to be made in detail with KENO or any other code. 13 refs., 16 figs., 13 tabs.

  12. Star of Condor - A strontium critical velocity experiment, Peru, 1983

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T.; Foeppl, H.; Valenzuela, A.

    1986-01-01

    'Star of Condor' was a critical velocity experiment using Sr vapor produced in a radial shaped charge, which was carried to 571.11 km altitude on a Taurus-Tomahawk rocket launched from Punto Lobos, Peru, and detonated in the plane of the magnetic field lines so that all ranges of pitch angles from parallel to B to perpendicular to B were covered. Sr has a critical velocity of 3.3 km/s, and from observation, 42.5 percent of the neutral Sr gas had a velocity component perpendicular to B exceeding that value. No Sr ion emissions were detected shortly after the burst with usual TV integration times. However, about 10 min after the detonation a faint field-aligned streak was discovered with long TV integration times. The brightness is estimated as 5 R, which, combined with the streak geometry, implies an ion production of 2.4 x 10 to the 19th ions. This is only 0.0036 percent ionization of the Sr vapor. All the ions could easily have been produced by thermal ionization from the original detonation thermal distribution. The breakup of the Sr gas into small bloblike structures may have allowed the high-energy electrons to escape before an ionization cascade could be produced. For whatever reason, the Alfven mechanism proposed for space plasmas in the absence of laboratory walls did not produce an ionization cascade in the experiment.

  13. Designing Critical Experiments in Support of Full Burnup Credit

    SciTech Connect

    Mueller, Don; Roberts, Jeremy A

    2008-01-01

    Burnup credit is the process of accounting for the negative reactivity due to fuel burnup and generation of parasitic absorbers over fuel assembly lifetime. For years, the fresh fuel assumption was used as a simple bound in criticality work for used fuel storage and transportation. More recently, major actinides have been included [1]. However, even this yields a highly conservative estimate in criticality calculations. Because of the numerous economical benefits including all available negative reactivity (i.e., full burnup credit) could provide [2], it is advantageous to work toward full burnup credit. Unfortunately, comparatively little work has been done to include non-major actinides and other fission products (FP) in burnup credit analyses due in part to insufficient experimental data for validation of codes and nuclear data. The Burnup Credit Criticality Experiment (BUCCX) at Sandia National Laboratory was a set of experiments with {sup 103}Rh that have relevance for burnup credit [3]. This work uses TSUNAMI-3D to investigate and adjust a BUCCX model to match isotope-specific, energy-dependent k{sub eff} sensitivity profiles to those of a representative high-capacity cask model (GBC-32) [4] for each FP of interest. The isotopes considered are {sup 149}Sm, {sup 143}Nd, {sup 103}Rh, {sup 133}Cs, {sup 155}Gd, {sup 152}Sm, {sup 99}Tc, {sup 145}Nd, {sup 153}Eu, {sup 147}Sm, {sup 109}Ag, {sup 95}Mo, {sup 150}Sm, {sup 101}Ru, and {sup 151}Eu. The goal is to understand the biases and bias uncertainties inherent in nuclear data, and ultimately, to apply these in support of full burnup credit.

  14. SR90, strontium shaped-charge critical ionization velocity experiment

    NASA Technical Reports Server (NTRS)

    Wescott, Eugene M.; Stenbaek-Nielsen, Hans; Swift, Daniel W.; Valenzuela, Arnoldo; Rees, David

    1990-01-01

    In May 1986 an experiment was performed to test Alfven's critical ionization velocity (CIV) effect in free space, using the first high explosive shaped charge with a conical liner of strontium metal. The release, made at 540 km altitude at dawn twilight, was aimed at 48 deg to B. The background electron density was 1.5 x 10(exp 4) cu cm. A faint field-aligned Sr(+) ion streak with tip velocity of 2.6 km/s was observed from two optical sites. Using two calibration methods, it was calculated that between 4.5 x 10(exp 20) and 2 x 10(exp 21) ions were visible. An ionization time constant of 1920 s was calculated for Sr from the solar UV spectrum and ionization cross section which combined with a computer simulation of the injection predicts 1.7 x 10(exp 21) solar UV ions in the low-velocity part of the ion streak. Thus all the observed ions are from solar UV ionization of the slow (less than critical) velocity portion of the neutral jet. The observed neutral Sr velocity distribution and computer simulations indicate that 2 x 10(exp 21) solar UV ions would have been created from the fast (greater than critical) part of the jet. They would have been more diffuse, and were not observed. Using this fact it was estimated that any CIV ions created were less than 10(exp 21). It was concluded that future Sr CIV free space experiments should be conducted below the UV shadow height and in much larger background plasma density.

  15. ESADA Plutonium Program Critical Experiments: Power Distribution Measurements

    SciTech Connect

    Akkurt, H.

    2001-06-12

    In 1967, a series of critical experiments were conducted at the Westinghouse Reactor Evaluation Center (WREC) using mixed-oxide (MOX) PuO{sub 2}-UO{sub 2} and/or UO{sub 2} fuels in various lattices and configurations. These experiments were performed under the joint sponsorship of Empire State Atomic Development Associates (ESADA) plutonium program and Westinghouse. The purpose of these experiments was to develop experimental data useful in validating analytical methods used in the design of plutonium-bearing replacement fuel for water reactors. Three different fuel types were used during the experimental program: two MOX fuels and a low-enriched UO{sub 2} fuel. The MOX fuels were distinguished by their {sup 240}Pu content: 8 wt % {sup 240}Pu and 24 wt % {sup 240}Pu. Both MOX fuels contained 2.0 wt % PuO{sub 2} in natural UO{sub 2}. The UO{sub 2} fuel with 2.72 wt % enrichment was used for comparison with the plutonium data and for use in multiregion experiments.

  16. Experiences of critical care nurses caring for unresponsive patients.

    PubMed

    Villanueva, N E

    1999-08-01

    Grounded theory methodology was utilized to explore the experiences of critical care nurses caring for patients who were unable to respond due to a traumatic brain injury or receiving neuromuscular blocking agents. The registered nurses participating in the study worked in a neuroscience intensive care unit. Saturation of the categories was achieved with 16 interviews. The core category that emerged from the study is Giving the Patient a Chance. The subcategories of Learning about My Patient, Maintaining and Monitoring, Talking to My Patient, Working with Families, Struggling with Dilemmas and Personalizing the Experience all centered upon the focus of doing everything to help the patient attain the best possible outcome. Factors influencing each of the subcategories were identified such as the acuity of the patient, experience level of the nurse and the presence or absence of family members or significant others. These factors accounted for the variations in the nurses' experience. Several reasons accounting for the variations were determined. The study identified areas that need to be addressed in both general nursing education and nursing practice, such as instruction on talking to comatose patients, working with families and orientation information for nurses new to caring for these populations. Recommendations for improvement in these areas, as well as for future studies are discussed. PMID:10553569

  17. The Relationships of Critical Thinking Skills, Critical Thinking Dispositions, and College Experiences of Theological Students in Indonesia

    ERIC Educational Resources Information Center

    Soeherman, Sylvia

    2010-01-01

    The purposes of this study were to assess the critical thinking skills of theological students in Indonesia and to explore the relationships between these students' critical thinking skills and their demographic profiles, critical thinking dispositions, and college experiences. All third-year students who pursued either the Sarjana Theologi (a…

  18. Nuclear criticality safety: 2-day training course

    SciTech Connect

    Schlesser, J.A.

    1997-02-01

    This compilation of notes is presented as a source reference for the criticality safety course. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used as Los Alamos; be able to identify examples of circumstances present during criticality accidents; have participated in conducting two critical experiments; be asked to complete a critique of the nuclear criticality safety training course.

  19. The Meadowhurst Experience: Phases in the Process of Educational Criticism.

    ERIC Educational Resources Information Center

    Barone, Thomas E., Jr.

    1982-01-01

    This article addresses the issue of what the process of participating in educational criticism feels like. Certain intellectual and emotional pleasures and perplexities that were confronted by the author while taking part in an educational criticism project are discussed. (CJ)

  20. Critical experiments at Sandia National Laboratories : technical meeting on low-power critical facilities and small reactors.

    SciTech Connect

    Harms, Gary A.; Ford, John T.; Barber, Allison Delo

    2010-11-01

    Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE since the 1960's. Over this period, the research reactor facilities at Sandia have had a primary mission to provide appropriate nuclear radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor III (SPR-III), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The SPR-III is currently defueled. The SPR Facility (SPRF) has hosted a series of critical experiments. A purpose-built critical experiment was first operated at the SPRF in the late 1980's. This experiment, called the Space Nuclear Thermal Propulsion Critical Experiment (CX), was designed to explore the reactor physics of a nuclear thermal rocket motor. This experiment was fueled with highly-enriched uranium carbide fuel in annular water-moderated fuel elements. The experiment program was completed and the fuel for the experiment was moved off-site. A second critical experiment, the Burnup Credit Critical Experiment (BUCCX) was operated at Sandia in 2002. The critical assembly for this experiment was based on the assembly used in the CX modified to accommodate low-enriched pin-type fuel in water moderator. This experiment was designed as a platform in which the reactivity effects of specific fission product poisons could be measured. Experiments were carried out on rhodium, an important fission product poison. The fuel and assembly hardware for the BUCCX remains at Sandia and is available for future experimentation. The critical experiment currently in operation at the SPRF is the Seven Percent Critical Experiment (7uPCX). This experiment is designed to provide benchmark

  1. Critical Incidents in Multicultural Training: An Examination of Student Experiences

    ERIC Educational Resources Information Center

    Coleman, M. Nicole

    2006-01-01

    This study examined critical incidents in graduate students' multicultural counseling training. Trainees (N=59) were asked to describe a critical incident and their multicultural training environment by responding to a critical incident protocol and the multicultural environment Inventory-Revised (D. B. Pope-Davis, W. M. Liu, J. Nevitt, & R. L.…

  2. Los Alamos National Laboratory.

    ERIC Educational Resources Information Center

    Hammel, Edward F., Jr.

    1982-01-01

    Current and post World War II scientific research at the Los Alamos National Laboratory (New Mexico) is discussed. The operation of the laboratory, the Los Alamos consultant program, and continuation education, and continuing education activities at the laboratory are also discussed. (JN)

  3. Comparison and analysis of 2-D simulation results with two implosion radiation experiments on the Los Alamos Pegasus I and Pegasus II capacitor banks

    SciTech Connect

    Peterson, D.L.; Bowers, R.L.; Lebeda, C.F.; Matuska, W.; Benage, J.; Idzorek, G.; Oona, H.; Stokes, J.; Roderick, N.F.

    1995-09-01

    Two experiments, PegI-41, conducted on the Los Alamos Pegasus I capacitor bank, and PegII-25, on the Pegasus II bank, consisted of the implosions of 13 mg (nominal), 5 cm radius, 2 cm high thin cylindrical aluminum foils resulting in soft x-ray radiation pulses from the plasma thermalization on axis. The implosions were conducted in direct-drive (no intermediate switching) mode with peak currents of about 4 MA and 5 MA respectively, and implosion times of about 2.5 {micro}s and 2.0 {micro}s. A radiation yield of about 250 kJ was measured for PegII-25. The purpose of these experiments was to examine the physics of the implosion and relate this physics to the production of the radiation pulse and to provide detailed experimental data which could be compared with 2-D radiation-magnetohydrodynamic (RMHD) simulations. Included in the experimental diagnostic suites were faraday rotation and dB/dt current measurements, a visible framing camera, an x-ray stripline camera, time-dependent spectroscopy, bolometers and XRD`S. A comparison of the results from these experiments shows agreement with 2-D simulation results in the instability development, current, and radiation pulse data, including the pulsewidth, shape, peak power and total radiation yield as measured by bolometry. Instabilities dominate the behavior of the implosion and largely determine the properties of the resulting radiation pulse. The 2-D simulations can be seen to be an important tool in understanding the implosion physics.

  4. Clinical review: The Israeli experience: conventional terrorism and critical care

    PubMed Central

    Aschkenasy-Steuer, Gabriella; Shamir, Micha; Rivkind, Avraham; Mosheiff, Rami; Shushan, Yigal; Rosenthal, Guy; Mintz, Yoav; Weissman, Charles; Sprung, Charles L; Weiss, Yoram G

    2005-01-01

    Over the past four years there have been 93 multiple-casualty terrorist attacks in Israel, 33 of them in Jerusalem. The Hadassah-Hebrew University Medical Center is the only Level I trauma center in Jerusalem and has therefore gained important experience in caring for critically injured patients. To do so we have developed a highly flexible operational system for managing the general intensive care unit (GICU). The focus of this review will be on the organizational steps needed to provide operational flexibility, emphasizing the importance of forward deployment of intensive care unit personnel to the trauma bay and emergency room and the existence of a chain of command to limit chaos. A retrospective review of the hospital's response to multiple-casualty terror incidents occurring between 1 October 2000 and 1 September 2004 was performed. Information was assembled from the medical center's trauma registry and from GICU patient admission and discharge records. Patients are described with regard to the severity and type of injury. The organizational work within intensive care is described. Finally, specific issues related to the diagnosis and management of lung, brain, orthopedic and abdominal injuries, caused by bomb blast events associated with shrapnel, are described. This review emphasizes the importance of a multidisciplinary team approach in caring for these patients. PMID:16277738

  5. Integrated verification experiment data collected as part of the Los Alamos National Laboratory`s Source Region program. Appendix F: Regional data from Lawrence Livermore National Laboratory and Sandia National Laboratory Seismic Networks

    SciTech Connect

    Taylor, S.R.

    1993-06-11

    A dataset of regional seismograms assembled for a series of Integrated Verification Experiments conducted by the Los Alamos National Laboratory Source Region program is described. The seismic data has been assembled from networks operated by Lawrence Livermore National Laboratory and Sandia National Laboratory. Examples of the data are shown and basic recording characteristics of the network are described. The seismograms are available on a data tape in SAC format upon request.

  6. Experiment to investigate anti. nu. /sub. mu. /. -->. anti. nu. /sub e/ oscillations at Los Alamos Meson Physics Facility

    SciTech Connect

    Kruse, H.W.; Toevs, J.W.

    1981-01-01

    An experiment, being planned at LAMPF, aims to investigate a possible neutrino oscillation channel, anti ..nu../sub ..mu../ ..-->.. anti ..nu../sub e/. If anti ..nu../sub ..mu../, produced in the LAMPF beam stop, oscillate to anti ..nu../sub e/, then interactions anti ..nu../sub e/ + p ..-->.. e/sup +/ + n, may be detected. A large volume liquid scintillator (4470 liter) emplaced at 33 m from the beam stop, detects e/sup +/ and n, after moderation in the hydrogenous liquid and capture in Gd, loaded into the scintillator. Our anticipated signal rate is currently estimated at 1.67 (sigma m/sup 2/)/sup 2//day assuming full amplitude oscillation. The corresponding counting rate, assuming all anti ..nu../sub ..mu../ have oscillated to anti ..nu../sub e/ at the detector is 1.5/day. Cosmic rates are estimated at 0.033/day. Correlated backgrounds from the beam stop are calculated to be small in comparison to cosmic events, except for reactions of ..nu../sub e/ in Pb. These reactions may be reduced with an Fe shield within the detector. With the above rate, a limit on the sensitivity of our experiment for the value of sigma m/sup 2/ is estimated at 0.12 eV/sup 2/ with 70 days of counting. Detector features, estimated background rates, and sensitivity values are discussed.

  7. Assessment as Critical Praxis: A Community College Experience.

    ERIC Educational Resources Information Center

    Cameron, Jeanne; Walsh, Philip; Stavenhagen Helgren, Tina; Kobritz, Barbara

    2002-01-01

    Describes a program for assessing student learning at a community college using critical theories of knowledge and the learning process. Finds all measures of learning indicate significant improvement in learning outcomes. Records and discusses the program methodology within the framework of critical pedagogical theory. (Author/KDR)

  8. Critical Pedagogy: EFL Teachers' Views, Experience and Academic Degrees

    ERIC Educational Resources Information Center

    Mahmoodarabi, Mahsa; Khodabakhsh, Mohammad Reza

    2015-01-01

    Although critical pedagogy has brought about positive changes in the field of education by shifting from traditional pedagogy to emancipatory pedagogy, not much attention has been paid to the factors affecting teachers' beliefs of critical pedagogy and only few studies have been conducted to design reliable and valid instruments to study EFL…

  9. Stockpile Stewardship: Los Alamos

    SciTech Connect

    McMillan, Charlie; Morgan, Nathanial; Goorley, Tom; Merrill, Frank; Funk, Dave; Korzekwa, Deniece; Laintz, Ken

    2012-01-26

    "Heritage of Science" is a short video that highlights the Stockpile Stewardship program at Los Alamos National Laboratory. Stockpile Stewardship was conceived in the early 1990s as a national science-based program that could assure the safety, security, and effectiveness of the U.S. nuclear deterrent without the need for full-scale underground nuclear testing. This video was produced by Los Alamos National Laboratory for screening at the Lab's Bradbury Science Museum in Los Alamos, NM and is narrated by science correspondent Miles O'Brien.

  10. Stockpile Stewardship: Los Alamos

    ScienceCinema

    McMillan, Charlie; Morgan, Nathanial; Goorley, Tom; Merrill, Frank; Funk, Dave; Korzekwa, Deniece; Laintz, Ken

    2014-08-12

    "Heritage of Science" is a short video that highlights the Stockpile Stewardship program at Los Alamos National Laboratory. Stockpile Stewardship was conceived in the early 1990s as a national science-based program that could assure the safety, security, and effectiveness of the U.S. nuclear deterrent without the need for full-scale underground nuclear testing. This video was produced by Los Alamos National Laboratory for screening at the Lab's Bradbury Science Museum in Los Alamos, NM and is narrated by science correspondent Miles O'Brien.

  11. Proceedings of the Nuclear Criticality Technology and Safety Project Workshop

    SciTech Connect

    Sanchez, R.G.

    1994-01-01

    This report is the proceedings of the annual Nuclear Criticality Technology and Safety Project (NCTSP) Workshop held in Monterey, California, on April 16--28, 1993. The NCTSP was sponsored by the Department of Energy and organized by the Los Alamos Critical Experiments Facility. The report is divided into six sections reflecting the sessions outlined on the workshop agenda.

  12. Does military sexual trauma moderate the impact of critical warzone experiences?

    PubMed

    Wilson, Laura C; Simmons, Brittany L; Leheney, Emma K; Ballman, Alesha D; Meyer, Eric C; DeBeer, Bryann B; Morissette, Sandra B; Kimbrel, Nathan A

    2015-09-30

    The present research sought to replicate the finding that military sexual trauma (MST) moderates the effect of critical warzone experiences on mental health outcomes in a sample of male veterans. One-hundred eighty-one male veterans completed measures of MST, critical warzone experiences, and mental health symptoms. The hypothesized interaction was not significant, nor was a significant main effect observed for MST. In contrast, both critical warzone experiences and childhood maltreatment had significant main effects. PMID:26210649

  13. Criticality experiments with neutron flux traps containing voids

    SciTech Connect

    Bierman, S.R.

    1990-04-01

    A research program was initiated for the US Department of Energy (DOE) by the Sandia National Laboratory Transportation Systems Development Department in 1982 to provide benchmark type experimental criticality data in support of the design and safe operations of nuclear fuel transportation systems. The overall objective of the program is to identify and provide the experimental data needed to form a consistent, firm, and complete data base for verifying calculational models used in the criticality analyses of nuclear transport and related systems. 2 refs., 6 figs., 7 tabs.

  14. DETERMINISTIC TRANSPORT METHODS AND CODES AT LOS ALAMOS

    SciTech Connect

    J. E. MOREL

    1999-06-01

    The purposes of this paper are to: Present a brief history of deterministic transport methods development at Los Alamos National Laboratory from the 1950's to the present; Discuss the current status and capabilities of deterministic transport codes at Los Alamos; and Discuss future transport needs and possible future research directions. Our discussion of methods research necessarily includes only a small fraction of the total research actually done. The works that have been included represent a very subjective choice on the part of the author that was strongly influenced by his personal knowledge and experience. The remainder of this paper is organized in four sections: the first relates to deterministic methods research performed at Los Alamos, the second relates to production codes developed at Los Alamos, the third relates to the current status of transport codes at Los Alamos, and the fourth relates to future research directions at Los Alamos.

  15. Critical Incidents in Multicultural Supervision: Exploring Supervisees' and Supervisors' Experiences

    ERIC Educational Resources Information Center

    Toporek, Rebecca L.; Ortega-Villalobos, Lideth; Pope-Davis, Donald B.

    2004-01-01

    Reports of supervisors' and supervisees' critical incidents in multicultural supervision were used to (a) explore events in supervision that influenced supervisees' multicultural competence, (b) explore how supervision was experienced differently by supervisors and supervisees, and (c) identify recommendations for improving multicultural…

  16. Critical and Creative Thinking Nexus: Learning Experiences of Doctoral Students

    ERIC Educational Resources Information Center

    Brodin, Eva M.

    2016-01-01

    Critical and creative thinking constitute important learning outcomes at doctoral level across the world. While the literature on doctoral education illuminates this matter through the lens of experienced senior researchers, the doctoral students' own perspective is missing. Based upon interviews with 14 doctoral students from four disciplines at…

  17. Effects of Diversity Experiences on Critical Thinking Skills: Who Benefits?

    ERIC Educational Resources Information Center

    Loes, Chad; Pascarella, Ernest; Umbach, Paul

    2012-01-01

    This study analyzed data from the Wabash National Study of Liberal Arts Education to estimate the unique effects of exposure to classroom diversity and involvement in interactional diversity on growth in critical thinking skills during the first year of college. Net of important confounding influences, neither classroom nor interactional diversity…

  18. Learning to Think Critically: A Visual Art Experiment

    ERIC Educational Resources Information Center

    Bowen, Daniel H.; Greene, Jay P.; Kisida, Brian

    2014-01-01

    This article examines whether exposure to the arts has an effect on the ability of students to engage in critical thinking. We conduct a randomized controlled trial involving 3,811 students who were assigned by lottery to participate in a School Visit Program at the newly opened Crystal Bridges Museum of American Art. Students who participated in…

  19. Experiences of Latino Couples in Relationship Education: A Critical Analysis

    ERIC Educational Resources Information Center

    Perez, Carlos; Brown, Matthew D.; Whiting, Jason B.; Harris, Steven M.

    2013-01-01

    There exists a need to better understand the applicability of Marriage and Relationship Education (MRE) initiatives with diverse populations. This study presents findings from focus groups with Latino men and women (N = 16) who participated in MRE classes. A critical theory approach guided the researchers who used grounded theory methodology to…

  20. Learning Experiences to Develop Critical Thinking through Understanding by Design

    ERIC Educational Resources Information Center

    Williams, David; Williams, Margot

    2009-01-01

    In some classrooms, gifted students are not exposed to the large and complex body of information and knowledge available today; instead, they are limited to what is deemed appropriate for the majority of their classmates. As a result, capable bright students may not develop the critical thinking skills necessary to analyze, synthesize, and…

  1. Critical Investigations into Interns' Urban Teaching Apprenticeship Experiences

    ERIC Educational Resources Information Center

    Lockhart, John

    2009-01-01

    A critical task for public school teachers is to build and maintain productive relationships with their students, especially to facilitate learning. That task is particularly important in preparing new teachers for urban schools because cultural differences between the majority of urban teachers and their students can complicate and impair those…

  2. Feasibility of Electrostriction for Measurement of the Critical Temperature in the Critical Viscosity Experiment

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Moldover, Michael R.

    1993-01-01

    The large compressibility of a pure fluid near its critical point is a potential means of measuring the critical temperature. At the suggestion of Prof. Ferrell we observed electrostriction in xenon by applying a large voltage across a small, open capacitor immersed in the sample and then measuring the capacitance change caused by the subsequent increase in the xenon's local density. This scheme was attractive because the compressibility is a large, well-understood effect and because we were already familiar with low-voltage capacitance measurements. We found qualitative agreement with our initial expectations based on the fluid's compressibility. However, we also found an additional effect comparable in size to the expected electrostriction but proportional to the applied voltage. We have no explanation for this effect. Thus, given the Science Panel's recommendation against investing extensive effort in this direction, we are abandoning further development of an alternate means for measuring the critical temperature.

  3. Calculation of Critical Experiments involving U(37)O2F2 Solution

    SciTech Connect

    Goluoglu, K.L.

    2006-03-03

    Critical experiments were conducted at the Oak Ridge Critical Experiment Facility (ORCEF) to determine the critical concentration for an unreflected 69.2-cm-diameter sphere of UO{sub 2}F{sub 2}, at an enrichment of {approx}37 percent U{sup 235}, by weight. These experiments were a continuation of previous efforts to determine critical dimensions for fissile materials in simple geometry. Some of the earlier experiments in this vessel have been published as part of the OECD handbook. The reports concerning these experiments have only recently become available. Until August 2005, Refs. 2 and 3 were still classified. These documents, along with experimental logbooks and unclassified papers available on the experimental campaign and facility are being used to generate a computer model for this critical experiment.

  4. The Experiences of Neophyte Teachers: A Critical Constructivist Assessment.

    ERIC Educational Resources Information Center

    Goddard, J. Tim; Foster, Rosemary Y.

    2001-01-01

    Interviewed beginning teachers to examine their experiences and the extent to which their preservice programs adequately prepared them for teaching. Results revealed six conceptual and temporal states through which they passed during their initial experiences: archetype; approaching the gates; clearing the gates; the gloss wears off;…

  5. Critical care air transport team (CCATT) nurses' deployed experience.

    PubMed

    Brewer, Theresa L; Ryan-Wenger, Nancy A

    2009-05-01

    The objective of this study was to use descriptive and phenomenological methods with Critical Care Air Transport Team (CCATT) nurses to identify knowledge and skills required to provide care for critically ill patients in a combat environment. Unstructured interviews, focus groups, written narratives, group interviews, participant observation, and review of in-flight documentation of care were used to obtain data from 23 registered nurses who had deployed with CCATT missions. Dimensions that emerged from the data included: clinical and operational competence, personal, physical, and psychosocial readiness, soldier and survival skills, leadership, administrative concerns, group identification and integration, aircraft air and evacuation familiarity, and nurse characteristics. This information should be shared with CCATT trainers and unit personnel to better prepare them for the realities of future deployments. Future research could incorporate these data into a self-assessment scale to evaluate CCATT nurses' readiness for future deployments. PMID:20731282

  6. Los Alamos Science: Number 16

    SciTech Connect

    Cooper, N.G.

    1988-01-01

    It was an unusually stimulating day and a half at Los Alamos when two Nobel Laureates in physiology, a leading paleontologist, and a leading bio-astrophysicist came together to discuss ''Unsolved Problems in the Science of Life,'' the topic of the second in a series of special meetings sponsored by the Fellows of the Laboratory. Just like the first one on ''Creativity in Science,'' this colloquium took us into a broader arena of ideas and viewpoints than is our usual daily fare. To contemplate the evolution and mysteries of intelligent life from the speakers' diverse points of view at one time, in one place was indeed a rare experience.

  7. Los Alamos offers Fellowships

    NASA Astrophysics Data System (ADS)

    Los Alamos National Laboratory in New Mexico is calling for applications for postdoctoral appointments and research fellowships. The positions are available in geoscience as well as other scientific disciplines.The laboratory, which is operated by the University of California for the Department of Energy, awards J. Robert Oppenheimer Research Fellowships to scientists that either have or will soon complete doctoral degrees. The appointments are for two years, are renewable for a third year, and carry a stipend of $51,865 per year. Potential applicants should send a resume or employment application and a statement of research goals to Carol M. Rich, Div. 89, Human Resources Development Division, MS P290, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 by mid-November.

  8. Experiments in software reliability - Life-critical applications

    NASA Technical Reports Server (NTRS)

    Dunham, J. R.

    1986-01-01

    The paper discusses four reliability data gathering experiments which were conducted using a small sample of programs for two problems having ultrareliability requirements, n-version programming for fault detection, and repetitive run modeling for failure and fault rate estimation. The experimental results agree with those of Nagel and Skrivan in that the program error rates suggest an approximate log-linear pattern and the individual faults occurred with significantly different error rates. Additional analysis of the experimental data raises new questions concerning the phenomenon of interacting faults. This phenomenon may provide one explanation for software reliability decay. The fourth experiment underscored the difficulty in distinguishing between observations of deficiencies in the design of the algorithm and observations of software faults for real-time process control software. These experiments are a part of a program of serial experiments being pursued by the System Validation Methods of NASA-Langley Research Center to find a means of credibly performing reliability evaluations of flight control software.

  9. The Los Alamos primer

    SciTech Connect

    Serber, R.

    1992-01-01

    This book contains the 1943 lecture notes of Robert Serber. Serber was a protege of J. Robert Oppenheimer and member of the team that built the first atomic bomb - reveal what the Los Alamos scientists knew, and did not know, about the terrifying weapon they were building.

  10. Criticality: the experience of developing an interactive educational tool based on board games.

    PubMed

    Gibson, Vanessa; Douglas, Margaret

    2013-12-01

    Critical care services have seen many changes over recent years prompted by the seminal paper by the Department of Health (2000) Comprehensive critical care: A review of adult critical care services. This led to the expansion of critical care services with the resultant recruitment of large numbers of nurses new to critical care. Northumbria and other Universities within the UK were commissioned to provide formal education to critical care nurses and developed Foundations in Acute and Critical Care Module to provide nurses new to critical care, or from other acute clinical settings, with the knowledge and skills to manage this complex group of patients. The aim of this paper is to share the authors' experience of developing "Criticality" a board game designed to formatively assess learning amongst critical care nurses following a formal taught module in a Higher Education Institution (HEI) and prior to the summative assessment. Author experience suggests that Criticality is a useful revision tool and also fun and interactive which helped the students to identify strengths and weaknesses in their knowledge base and thus direct their revision prior to summative assessment. PMID:23462518

  11. Los Alamos Explosives Performance Key to Stockpile Stewardship

    ScienceCinema

    Dattelbaum, Dana

    2015-01-05

    As the U.S. Nuclear Deterrent ages, one essential factor in making sure that the weapons will continue to perform as designed is understanding the fundamental properties of the high explosives that are part of a nuclear weapons system. As nuclear weapons go through life extension programs, some changes may be advantageous, particularly through the addition of what are known as "insensitive" high explosives that are much less likely to accidentally detonate than the already very safe "conventional" high explosives that are used in most weapons. At Los Alamos National Laboratory explosives research includes a wide variety of both large- and small-scale experiments that include small contained detonations, gas and powder gun firings, larger outdoor detonations, large-scale hydrodynamic tests, and at the Nevada Nuclear Security Site, underground sub-critical experiments.

  12. Los Alamos Explosives Performance Key to Stockpile Stewardship

    SciTech Connect

    Dattelbaum, Dana

    2014-11-03

    As the U.S. Nuclear Deterrent ages, one essential factor in making sure that the weapons will continue to perform as designed is understanding the fundamental properties of the high explosives that are part of a nuclear weapons system. As nuclear weapons go through life extension programs, some changes may be advantageous, particularly through the addition of what are known as "insensitive" high explosives that are much less likely to accidentally detonate than the already very safe "conventional" high explosives that are used in most weapons. At Los Alamos National Laboratory explosives research includes a wide variety of both large- and small-scale experiments that include small contained detonations, gas and powder gun firings, larger outdoor detonations, large-scale hydrodynamic tests, and at the Nevada Nuclear Security Site, underground sub-critical experiments.

  13. Critical care delivery: the experience of a civilian terrorist attack.

    PubMed

    Shirley, P J

    2006-03-01

    It has been recognised for some time that a terrorist incident was threatened in the U.K. and it has been noted previously in the JRAMC that the locations for terrorist atrocities are likely to be more diverse than previously experienced. July 7th 2005 witnessed the first terrorist suicide bombing on the U.K. mainland, targeting the public transport system in London. These attacks were unprecedented in both scale and intensity but they were anticipated in London. However there were clear difficulties, relating to multiple sites, their location underground and early problems with communication (2). This article highlights some of the experiences and learning points of the Intensive Care Medicine Service at the Royal London Hospital (RLH) in the wake of the July 7th bombings. The RLH was the single biggest receiver of casualties (195); seven of whom were admitted to the Intensive Care Unit. The Defence Medical Services have tri-service representation (both regular and reserve) at the RLH in Emergency Medicine and Pre-hospital Care, Surgical Services and Intensive Care Medicine. PMID:16749465

  14. Turning Experiences into Critical Re?ections: Examples from Taiwanese In-Service Teachers

    ERIC Educational Resources Information Center

    Chi, Feng-ming

    2013-01-01

    The aims of this paper are twofold: to investigate how Taiwanese teachers of English as a Foreign Language turned experiences into critical reflections via journal writings and to describe how they gauged critical reflections as teaching inquiry. The participants were 12 Taiwanese in-service teachers enrolled in an elective course entitled "Doing…

  15. Analysis of fresh fuel critical experiments appropriate for burnup credit validation

    SciTech Connect

    DeHart, M.D.; Bowman, S.M.

    1995-10-01

    The ANS/ANS-8.1 standard requires that calculational methods used in determining criticality safety limits for applications outside reactors be validated by comparison with appropriate critical experiments. This report provides a detailed description of 34 fresh fuel critical experiments and their analyses using the SCALE-4.2 code system and the 27-group ENDF/B-IV cross-section library. The 34 critical experiments were selected based on geometry, material, and neutron interaction characteristics that are applicable to a transportation cask loaded with pressurized-water-reactor spent fuel. These 34 experiments are a representative subset of a much larger data base of low-enriched uranium and mixed-oxide critical experiments. A statistical approach is described and used to obtain an estimate of the bias and uncertainty in the calculational methods and to predict a confidence limit for a calculated neutron multiplication factor. The SCALE-4.2 results for a superset of approximately 100 criticals are included in uncertainty analyses, but descriptions of the individual criticals are not included.

  16. Historic Manhattan Project Sites at Los Alamos

    ScienceCinema

    McGehee, Ellen

    2014-05-22

    The Manhattan Project laboratory constructed at Los Alamos, New Mexico, beginning in 1943, was intended from the start to be temporary and to go up with amazing speed. Because most of those WWII-era facilities were built with minimal materials and so quickly, much of the original infrastructure was torn down in the late '40s and early '50s and replaced by more permanent facilities. However, a few key facilities remained, and are being preserved and maintained for historic significance. Four such sites are visited briefly in this video, taking viewers to V-Site, the buildings where the first nuclear explosive device was pre-assembled in preparation for the Trinity Test in Southern New Mexico. Included is another WWII area, Gun Site. So named because it was the area where scientists and engineers tested the so-called "gun method" of assembling nuclear materials -- the fundamental design of the Little Boy weapon that was eventually dropped on Hiroshima. The video also goes to Pajarito Site, home of the "Slotin Building" and "Pond Cabin." The Slotin Building is the place where scientist Louis Slotin conducted a criticality experiment that went awry in early 1946, leading to his unfortunate death, and the Pond Cabin served the team of eminent scientist Emilio Segre who did early chemistry work on plutonium that ultimately led to the Fat Man weapon.

  17. Cryogenic design of the liquid helium experiment ``critical dynamics in microgravity``

    SciTech Connect

    Moeur, W.A.; Adriaans, M.J.; Boyd, S.T.; Strayer, D.M.; Duncan, R.V. |

    1995-10-01

    Although many well controlled experiments have been conducted to measure the static properties of systems near criticality, few experiments have explored the transport properties in systems driven far away from equilibrium as a phase transition occurs. The cryogenic design of an experiment to study the dynamic aspect of critical phenomena is reported here. Measurements of the thermal gradient across the superfluid (He II) -- normal fluid (He I) interface in helium under microgravity conditions will be performed as a heat flux holds the system away from equilibrium. New technologies are under development for this experiment, which is in the definition phase for a space shuttle flight.

  18. Calculated k-effectives for light water reactor typical, U + Pu nitrate solution critical experiments

    SciTech Connect

    Primm, R.T. III; Mincey, J.F.

    1982-01-01

    The Department of Energy's Consolidated Fuel Reprocessing Program has as a goal the design of nuclear fuel reprocessing equipment. In order to validate computer codes used for criticality analyses in the design of such equipment, k-effectives have been calculated for several U + Pu nitrate solution critical experiments. As of January 1981, descriptions of 45 unpoisoned, U + Pu solution experiments were available in the open literature. Twelve of these experiments were performed with solutions which have physical characteristics typical of dissolved, light water reactor fuel. This paper contains a discussion of these twelve experiments, a review of the calculational procedure used to determine k-effectives, and the results of the calculations.

  19. Bibliography for nuclear criticality accident experience, alarm systems, and emergency management

    SciTech Connect

    Putman, V.L.

    1995-09-01

    The characteristics, detection, and emergency management of nuclear criticality accidents outside reactors has been an important component of criticality safety for as long as the need for this specialized safety discipline has been recognized. The general interest and importance of such topics receives special emphasis because of the potentially lethal, albeit highly localized, effects of criticality accidents and because of heightened public and regulatory concerns for any undesirable event in nuclear and radiological fields. This bibliography lists references which are potentially applicable to or interesting for criticality alarm, detection, and warning systems; criticality accident emergency management; and their associated programs. The lists are annotated to assist bibliography users in identifying applicable: industry and regulatory guidance and requirements, with historical development information and comments; criticality accident characteristics, consequences, experiences, and responses; hazard-, risk-, or safety-analysis criteria; CAS design and qualification criteria; CAS calibration, maintenance, repair, and testing criteria; experiences of CAS designers and maintainers; criticality accident emergency management (planning, preparedness, response, and recovery) requirements and guidance; criticality accident emergency management experience, plans, and techniques; methods and tools for analysis; and additional bibliographies.

  20. Science Requirements for a Space Flight Experiment Entitled Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Moldover, Michael R.

    1993-01-01

    We propose to measure in low gravity the viscosity of xenon close to its critical point. The accuracy will be sufficient to eliminate uncertainties currently associated with the analysis of l-g experiments. The measurements will provide the first direct observation of the predicted power-law divergence of viscosity in a pure fluid. The measurements will also strengthen Zeno's test of mode coupling theory by greatly increasing the reliability of the extrapolation of viscosity to low reduced temperatures. Our scientific objectives are described in more detail in one of the attached reports. The low-gravity experiment will be the final stage of a program whose completed ground-based stages are: (1) theoretical studies by one of the principal investigators (MRM) and coworkers, (2) critical viscosity measurements of binary liquid mixtures, (3) critical viscosity measurements of pure fluids in l-g, and development of a suitable vibration-insensitive viscometer. Our technical approach is described in the draft Science Requirements Document. One of us (MRM) has reviewed opportunities for critical phenomena research in low gravity. Both of us were co-principal investigators in the Thermal Equilibration Experiment in the Critical Point Facility, flown on IML-1 in 1992. From this experience, and from the technical maturity of our ground-based work, we believe our critical point viscometer is ready for development as a flight experiment.

  1. Critical experiments on low-enriched uranium oxide systems with H/U = 2. 03

    SciTech Connect

    Rothe, R E; Goebel, G R

    1982-02-01

    Seven critical experiments were performed on a horizontal split table machine using 4.48% enriched /sup 235/U uranium oxide (U/sub 3/O/sub 8/). The oxide was compacted to a density of 4.68 g/cm/sup 3/ and placed in 152-mm cubical aluminum cans. Water was added to achieve an H/U atomic ratio of 2.03. Various arrays of oxide cans were distributed on each half of the split table and the separation between halves reduced until criticality occurred. The critical table separation varied from 4.3 mm to 29.3 mm. These experiments were performed in both plastic and concrete reflectors. The first five experiments required the addition of a high-enriched (approx. 93% /sup 235/U) metal driver to achieve criticality. Critical uranium driver masses ranged from 2.765 kg to 13.730 kg for 5 x 5 x 5 arrays of uranium oxide cans. In all five cases, the center can of the array was deleted to accommodate the driver. The uranium oxide mass was 1859.6 kg. Two additional experiments in the plastic reflector contained either 9.3-mm- or 24.3-mm-thick plastic moderator material between the oxide cans. These latter experiments did not require a driver to achieve criticality; and the uranium oxide mass was 723.9 kg for the configuration having the thinner interstitial moderator and 452.4 kg for the other.

  2. Benchmark Evaluation of the Medium-Power Reactor Experiment Program Critical Configurations

    SciTech Connect

    Margaret A. Marshall; John D. Bess

    2013-02-01

    A series of small, compact critical assembly (SCCA) experiments were performed in 1962-1965 at the Oak Ridge National Laboratory Critical Experiments Facility (ORCEF) for the Medium-Power Reactor Experiment (MPRE) program. The MPRE was a stainless-steel clad, highly enriched uranium (HEU)-O2 fuelled, BeO reflected reactor design to provide electrical power to space vehicles. Cooling and heat transfer were to be achieved by boiling potassium in the reactor core and passing vapor directly through a turbine. Graphite- and beryllium-reflected assemblies were constructed at ORCEF to verify the critical mass, power distribution, and other reactor physics measurements needed to validate reactor calculations and reactor physics methods. The experimental series was broken into three parts, with the third portion of the experiments representing the beryllium-reflected measurements. The latter experiments are of interest for validating current reactor design efforts for a fission surface power reactor. The entire series has been evaluated as acceptable benchmark experiments and submitted for publication in the International Handbook of Evaluated Criticality Safety Benchmark Experiments and in the International Handbook of Evaluated Reactor Physics Benchmark Experiments.

  3. Simulated and Virtual Science Laboratory Experiments: Improving Critical Thinking and Higher-Order Learning Skills

    ERIC Educational Resources Information Center

    Simon, Nicole A.

    2013-01-01

    Virtual laboratory experiments using interactive computer simulations are not being employed as viable alternatives to laboratory science curriculum at extensive enough rates within higher education. Rote traditional lab experiments are currently the norm and are not addressing inquiry, Critical Thinking, and cognition throughout the laboratory…

  4. Stakeholder Perceptions of the Positive Benefits and Critical Challenges Involved in Student Service-Learning Experiences

    ERIC Educational Resources Information Center

    Hohenthal, K. Darcy

    2010-01-01

    The Bolman and Deal (2003) Four-Frame Model was adapted in this qualitative phenomenological research study to describe how stakeholders experience student service-learning. The study presents how students perceive the positive benefits and critical challenges encountered in their service-learning experience; how professors perceive the positive…

  5. The metaphor of experience and the experience of metaphor: critical reflection on a contemplative process toward aliveness and compassion.

    PubMed

    Kuchan, Karen L

    2009-01-01

    An epistemological web invites critical reflection and the possibility of new ideas emerging in the space between experience and different ways of thinking. A web offers a postmodern method of a hermeneutic of experience and a way of knowing that creates space for a robust, flexible, dynamic process of critical reflection and discovery. The following article utilizes an inter-textual epistemological web (see Figure 1, p. 4) to answer the question, "Do metaphors of experience and experiences of metaphor during contemplative healing prayer with a spiritual director nurture a transformational process toward aliveness and compassion?" How can one discover and communicate this reality in dialog with Hebrew scripture, psychoanalytic theory, affective neuroscience and ways of thinking about contemplative transformation? PMID:20306943

  6. Maternal critical care: what can we learn from patient experience? A qualitative study

    PubMed Central

    Hinton, Lisa; Locock, Louise; Knight, Marian

    2015-01-01

    Objective For every maternal death, nine women develop severe maternal morbidity. Many of those women will need care in an intensive care unit (ICU) or high dependency unit (HDU). Critical care in the context of pregnancy poses distinct issues for staff and patients, for example, with breastfeeding support and separation from the newborn. This study aimed to understand the experiences of women who experience a maternal near miss and require critical care after childbirth. Setting Women and some partners from across the UK were interviewed as part of a study of experiences of near-miss maternal morbidity. Design A qualitative study, using semistructured interviews. Participants A maximum variation sample was recruited of 35 women and 11 partners of women who had experienced a severe maternal illness, which without urgent medical attention would have led to her death. 18 of the women were admitted to ICU or HDU. Results The findings are presented in three themes: being in critical care; being a new mother in critical care; transfer and follow-up after critical care. The study highlights the shock of requiring critical care for new mothers and the gulf between their expectations of birth and what actually happened; the devastation of being separated from their baby, how valuable access to their newborn was, if possible, and the importance of breast feeding; the difficulties of transfer and the need for more support; the value of follow-up and outreach to this population of critical care patients. Conclusions While uncommon, critical illness in pregnancy can be devastating for new mothers and presents a challenge for critical care and maternity staff. This study provides insights into these challenges and recommendations for overcoming them drawn from patient experiences. PMID:25916486

  7. Calculated K-effectives using ENDF/B-V data for U + Pu solution critical experiments

    SciTech Connect

    Primm, R.T. III; Mincey, J.F.

    1981-01-01

    Effective multiplication factors for 12 critical experiments have been calculated using multigroup cross sections derived from the ENDF/B-V library. All 12 experiments contained mixed plutonium and uranium nitrate solutions. The range of hydrogen-to-fissile plutonium atom ratios spanned by these experiments was 200 to 2200. A comparison with K-effectives calculated with ENDF/B-IV data is presented.

  8. Nuclear Forensics at Los Alamos National Laboratory

    SciTech Connect

    Podlesak, David W; Steiner, Robert E.; Burns, Carol J.; LaMont, Stephen P.; Tandon, Lav

    2012-08-09

    The overview of this presentation is: (1) Introduction to nonproliferation efforts; (2) Scope of activities at Los Alamos National Laboratory; (3) Facilities for radioanalytical work at LANL; (4) Radiochemical characterization capabilities; and (5) Bulk chemical and materials analysis capabilities. Some conclusions are: (1) Analytical chemistry measurements on plutonium and uranium matrices are critical to numerous defense and non-defense programs including safeguards accountancy verification measurements; (2) Los Alamos National Laboratory operates capable actinide analytical chemistry and material science laboratories suitable for nuclear material forensic characterization; (3) Actinide analytical chemistry uses numerous means to validate and independently verify that measurement data quality objectives are met; and (4) Numerous LANL nuclear facilities support the nuclear material handling, preparation, and analysis capabilities necessary to evaluate samples containing nearly any mass of an actinide (attogram to kilogram levels).

  9. Solution High-Energy Burst Assembly (SHEBA) results from subprompt critical experiments with uranyl fluoride fuel

    SciTech Connect

    Cappiello, C.C.; Butterfield, K.B.; Sanchez, R.G.; Bounds, J.A.; Kimpland, R.H.; Damjanovich, R.P.; Jaegers, P.J.

    1997-08-01

    Experiments were performed to measure a variety of parameters for SHEBA: behavior of the facility during transient and steady-state operation; characteristics of the SHEBA fuel; delayed-critical solution height vs solution temperature; initial reactor period and reactivity vs solution height; calibration of power level vs reactor power instrumentation readings; flux profile in SHEBA; radiation levels and neutron spectra outside the assembly for code verification and criticality alarm and dosimetry purposes; and effect on reactivity of voids in the fuel.

  10. Evaluation of Plutonium Hemisphere Critical Experiments Partially Reflected by Steel and Oil

    SciTech Connect

    John D. Bess

    2012-01-01

    A series of 15 critical experiments performed at the Rocky Flats Critical Mass Laboratory in the late 1960s were evaluated and then determined to represent acceptable benchmark experiments for the validation of calculational methods. This series of experiments was part of a larger set of experiments performed to evaluate operational safety margins at the Rocky Flats Plant. The experiments consisted of bare plutonium metal hemishells reflected by steel hemishells of increasing thickness and motor oil. The hemishell assembly was suspended within dual aluminum tanks. Criticality was achieved by pumping oil into the tanks such that effectively infinite reflection was achieved in all directions except directly above the assembly; then the critical oil height was recorded. The results of these experiments had been initially ignored because early computational methods had been inadequate to analyze partially-reflected configurations. The dominant uncertainties include the uncertainty in the average plutonium density and the composition of materials in the gaps between the plutonium hemishells. Simple and detailed benchmark models were developed. Eigenvalue calculations using MCNP5 and ENDF/B-VII.0 were within 2s of the benchmark values. This benchmark evaluation has been added to the ICSBEP Handbook.

  11. Experiment of Critical Swimming Speed of Fingerling Masu Salmon (Oncorhynchus masou masou) Using River Water

    NASA Astrophysics Data System (ADS)

    Izumi, Mattashi; Kato, Koh

    The authors conducted a field swimming experiment using cultured masu salmon (Oncorhynchus masou masou) fingerlings in order to study their critical swimming speed during their release into the river in the Iwaki River diversion weir. The experimental equipment was a small, rectangular cross-section channel, which was installed in a local riverbed at the fishway. The experiment was conducted using an average cross-sectional water flow velocity of 17 to 92 cm·s-1, and using masu salmon fingerlings from 4.8 to 7.1 cm in the length. River water temperature was between 13.7 and 20.6 °C. The critical swimming speed measured over 60 minutes was between 16 and 41 cm·s-1 and a positive correlation was found between the critical swimming speed and body length. The critical swimming speed measured by body length (BL) was 3.5 to 6.9 times (that is, the distance travelled per second based on body length), and the mean critical swimming speed was 5.5 (with a standard deviation of 1.1). Results showed that water temperature differences in the experiment had no significant effect on the critical swimming speed measured over 60 minutes.

  12. Simulated and Virtual Science Laboratory Experiments: Improving Critical Thinking and Higher-Order Learning Skills

    NASA Astrophysics Data System (ADS)

    Simon, Nicole A.

    Virtual laboratory experiments using interactive computer simulations are not being employed as viable alternatives to laboratory science curriculum at extensive enough rates within higher education. Rote traditional lab experiments are currently the norm and are not addressing inquiry, Critical Thinking, and cognition throughout the laboratory experience, linking with educational technologies (Pyatt & Sims, 2007; 2011; Trundle & Bell, 2010). A causal-comparative quantitative study was conducted with 150 learners enrolled at a two-year community college, to determine the effects of simulation laboratory experiments on Higher-Order Learning, Critical Thinking Skills, and Cognitive Load. The treatment population used simulated experiments, while the non-treatment sections performed traditional expository experiments. A comparison was made using the Revised Two-Factor Study Process survey, Motivated Strategies for Learning Questionnaire, and the Scientific Attitude Inventory survey, using a Repeated Measures ANOVA test for treatment or non-treatment. A main effect of simulated laboratory experiments was found for both Higher-Order Learning, [F (1, 148) = 30.32,p = 0.00, eta2 = 0.12] and Critical Thinking Skills, [F (1, 148) = 14.64,p = 0.00, eta 2 = 0.17] such that simulations showed greater increases than traditional experiments. Post-lab treatment group self-reports indicated increased marginal means (+4.86) in Higher-Order Learning and Critical Thinking Skills, compared to the non-treatment group (+4.71). Simulations also improved the scientific skills and mastery of basic scientific subject matter. It is recommended that additional research recognize that learners' Critical Thinking Skills change due to different instructional methodologies that occur throughout a semester.

  13. A short review of critical experiments performed at the Kurchatov Institute

    SciTech Connect

    Gagarinski, A.Yu.; Glushkov, Y.S.; Ponomarev-Stepnoi, N.N.

    1997-06-01

    Since the 1950s, the Institute of Atomic Energy (now the Russian Research Center Kurchatov Institute) has investigated nuclear reactors intended for various purposes. A summary of the present state of these assemblies is given in an attachment to the paper. A second attachment provides a brief description of critical experiments for small nuclear power systems intended for decentralized power generation. The critical assemblies for these experiments were moderated by water and zirconium hydride, and fuel elements ranged in enrichment from 5% to 95% uranium 235. 7 refs.

  14. Critical experiment tests of bowing and expansion reactivity calculations for LMRS

    SciTech Connect

    Schaefer, R.W.

    1988-01-01

    Experiments done in several LMR-type critical assemblies simulated core axial expansion, core radial expansion and bowing, coolant expansion, and control driveline expansion. For the most part new experimental techniques were developed to do these experiments. Calculations of the experiments basically used design-level methods, except when it was necessary to investigate complexities peculiar to the experiments. It was found that these feedback reactivities generally are overpredicted, but the predictions are within 30% of the experimental values. 14 refs., 2 figs., 4 tabs.

  15. GROWTH OF THE INTERNATIONAL CRITICALITY SAFETY AND REACTOR PHYSICS EXPERIMENT EVALUATION PROJECTS

    SciTech Connect

    J. Blair Briggs; John D. Bess; Jim Gulliford

    2011-09-01

    Since the International Conference on Nuclear Criticality Safety (ICNC) 2007, the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP) have continued to expand their efforts and broaden their scope. Eighteen countries participated on the ICSBEP in 2007. Now, there are 20, with recent contributions from Sweden and Argentina. The IRPhEP has also expanded from eight contributing countries in 2007 to 16 in 2011. Since ICNC 2007, the contents of the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments1' have increased from 442 evaluations (38000 pages), containing benchmark specifications for 3955 critical or subcritical configurations to 516 evaluations (nearly 55000 pages), containing benchmark specifications for 4405 critical or subcritical configurations in the 2010 Edition of the ICSBEP Handbook. The contents of the Handbook have also increased from 21 to 24 criticality-alarm-placement/shielding configurations with multiple dose points for each, and from 20 to 200 configurations categorized as fundamental physics measurements relevant to criticality safety applications. Approximately 25 new evaluations and 150 additional configurations are expected to be added to the 2011 edition of the Handbook. Since ICNC 2007, the contents of the 'International Handbook of Evaluated Reactor Physics Benchmark Experiments2' have increased from 16 different experimental series that were performed at 12 different reactor facilities to 53 experimental series that were performed at 30 different reactor facilities in the 2011 edition of the Handbook. Considerable effort has also been made to improve the functionality of the searchable database, DICE (Database for the International Criticality Benchmark Evaluation Project) and verify the accuracy of the data contained therein. DICE will be discussed in separate papers at ICNC 2011. The status of the ICSBEP and the IRPh

  16. Nuclear criticality safety experiments, calculations, and analyses: 1958 to 1982. Volume 1. Lookup tables

    SciTech Connect

    Koponen, B.L.; Hampel, V.E.

    1982-10-21

    This compilation contains 688 complete summaries of papers on nuclear criticality safety as presented at meetings of the American Nuclear Society (ANS). The selected papers contain criticality parameters for fissile materials derived from experiments and calculations, as well as criticality safety analyses for fissile material processing, transport, and storage. The compilation was developed as a component of the Nuclear Criticality Information System (NCIS) now under development at the Lawrence Livermore National Laboratory. The compilation is presented in two volumes: Volume 1 contains a directory to the ANS Transaction volume and page number where each summary was originally published, the author concordance, and the subject concordance derived from the keyphrases in titles. Volume 2 contains - in chronological order - the full-text summaries, reproduced here by permission of the American Nuclear Society from their Transactions, volumes 1-41.

  17. Safety analysis report for the Hanford Critical Mass Laboratory: Supplement No. 2. Experiments with heterogeneous assemblies

    SciTech Connect

    Gore, B.F.; Davenport, L.C.

    1981-04-01

    Factors affecting the safety of criticality experiments using heterogeneous assemblies are described and assessed. It is concluded that there is no substantial change in safety from experiments already being routinely performed at the Critical Mass Laboratory (CML), and that laboratory and personnel safety are adequately provided by the combination of engineered and administrative safety limits enforced at the CML. This conclusion is based on the analysis of operational controls, potential hazards, and the consequences of accidents. Contingencies considered that could affect nuclear criticality include manual changes in fuel loadings, water flooding, fire, explosion, loss of services, earthquake, windstorm, and flood. Other potential hazards considered include radiation exposure to personnel, and potential releases within the Assembly Room and outside to the environment. It is concluded that the Maximum Credible Nuclear Burst of 3 x 10/sup 18/ fissions (which served as the design basis for the CML) is valid for heterogeneous assemblies as well as homogeneous assemblies. This is based upon examination of the results of reactor destructive tests and the results of the SL-1 reactor destructive accident. The production of blast effects which might jeopardize the CML critical assembly room (of thick reinforced concrete) is not considered credible due to the extreme circumstances required to produce blast effects in reactor destructive tests. Consequently, it is concluded that, for experiments with heterogeneous assemblies, the consequences of the Maximum Credible Burst are unchanged from those previously estimated for experiments with homogeneous systems.

  18. The Impact of Simulation-Based Learning Experience on Critical Thinking Acquisition

    ERIC Educational Resources Information Center

    Rome, Candice

    2012-01-01

    The purpose of this comparative experimental project was to compare the impact of simulation-based learning experiences to traditional clinical rotations on critical thinking acquisition of associate nursing students within a maternal-child course. Innovative pedagogies have been integrated in nursing programs to augment inadequate clinical…

  19. 76 FR 40945 - Rensselaer Polytechnic Institute Critical Experiments Facility; Notice of Issuance of Renewed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-12

    ... Opportunity for Hearing published in the Federal Register on May 15, 2008 (73 FR 28170). The NRC received no... Impact for license renewal, noticed in the Federal Register on June 14, 2011 (76 FR 34770), and concluded... COMMISSION Rensselaer Polytechnic Institute Critical Experiments Facility; Notice of Issuance of...

  20. Using Compression Isotherms of Phospholipid Monolayers to Explore Critical Phenomena: A Biophysical Chemistry Experiment

    ERIC Educational Resources Information Center

    Gragson, Derek E.; Beaman, Dan; Porter, Rhiannon

    2008-01-01

    Two experiments are described in which students explore phase transitions and critical phenomena by obtaining compression isotherms of phospholipid monolayers using a Langmuir trough. Through relatively simple analysis of their data students gain a better understanding of compression isotherms, the application of the Clapeyron equation, the…

  1. Calculational assessment of critical experiments with mixed oxide fuel pin arrays moderated by organic solution

    SciTech Connect

    Smolen, G.R.

    1987-01-01

    Critical experiments have been conducted with organic-moderated mixed oxide (MOX) fuel pin assemblies at the Pacific Northwest Laboratory (PNL) Critical Mass Laboratory (CML). These experiments are part of a joint exchange program between the United States Department of Energy (USDOE) and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan in the area of criticality data development. The purpose of these experiments is to benchmark computer codes and cross-section libraries and to assess the reactivity difference between systems moderated by water and those moderated by an organic solution. Past studies have indicated that some organic mixtures may be better moderators than water. This topic is of particular importance to the criticality safety of fuel processing plants where fissile material is dissolved in organic solutions during the solvent extraction process. In the past, it has been assumed that the codes and libraries benchmarked with water-moderated experiments were adequate when performing design and licensing studies of organic-moderated systems. Calculations presented in this paper indicated that the SCALE code system and the 27-energy-group cross-section accurately compute k-effectives for organic moderated MOX fuel-pin assemblies. Furthermore, the reactivity of an organic solution with a 32-vol-% TBP/68-vol-% NPH mixture in a heterogeneous configuration is the same, for practical purposes, as water. 5 refs.

  2. The Experience of Critical Self-Reflection by Life Coaches: A Phenomenological Study

    ERIC Educational Resources Information Center

    Shaw, Deanna Lynn

    2012-01-01

    The purpose of this study was to describe the experience of critical self-reflection by life coaches. Life coaching is expanding within many disciplines including education, health care, business, social work, and wellness. Life coaching involves a coach working with an individual or groups aimed at effecting change for professional and personal…

  3. A Critical Dialectical Pluralistic Examination of the Lived Experience of Select Women Doctoral Students

    ERIC Educational Resources Information Center

    Onwuegbuzie, Anthony J.; Rosli, Roslinda; Ingram, Jacqueline M.; Frels, Rebecca K.

    2014-01-01

    The purpose of this study was to explore and to understand the daily life experiences of 8 women doctoral students who were in pursuit of their doctorates. A partially mixed concurrent dominant status design was utilized in this study embedded within a mixed methods phenomenological research lens and driven by a critical dialectical pluralistic…

  4. Development of Critical Thinking through Aesthetic Experience: The Case of Students of an Educational Department

    ERIC Educational Resources Information Center

    Raikou, Natassa

    2016-01-01

    This article addresses an application performed in tertiary education--a department of pedagogical and educational sciences--of a contemporary method, Transformative Learning through Aesthetic Experience. The method is based on the use of art and aims to reinforce and promote the development of critical thinking within educational settings.…

  5. Critical Race Theory, Disability Microaggressions and Latina/o Student Experiences in Special Education

    ERIC Educational Resources Information Center

    Dávila, Brianne

    2015-01-01

    This research draws upon critical race theory (CRT) to explore the experiences of Latina/o students in special education. It seeks to extend the theoretical construct of racial microaggressions and illustrate the additional layer of disability as I present data that are particular to the context of special education and the assigned label of…

  6. How Do Virtual World Experiences Bring about Learning? A Critical Review of Theories

    ERIC Educational Resources Information Center

    Loke, Swee-Kin

    2015-01-01

    While students do learn real-world knowledge and skills in virtual worlds, educators have yet to adequately theorise how students' virtual world experiences bring about this learning. This paper critically reviewed theories currently used to underpin empirical work in virtual worlds for education. In particular, it evaluated how applicable these…

  7. Interrogating Students' Perceptions of Their Online Learning Experiences with Brookfield's Critical Incident Questionnaire

    ERIC Educational Resources Information Center

    Phelan, Liam

    2012-01-01

    This article discusses whether the very act of accessing online students' experiences of teaching may itself foster students' sense of belonging to a learning community. The article reports and reflects on the application of Brookfield's critical incident questionnaire (CIQ) in postgraduate courses delivered online in 2008-2010 through the…

  8. Evaluation of Fission Product Critical Experiments and Associated Biases for Burnup Credit Validation

    SciTech Connect

    Mueller, Don; Rearden, Bradley T; Reed, Davis Allan

    2010-01-01

    One of the challenges associated with implementation of burnup credit is the validation of criticality calculations used in the safety evaluation; in particular the availability and use of applicable critical experiment data. The purpose of the validation is to quantify the relationship between reality and calculated results. Validation and determination of bias and bias uncertainty require the identification of sets of critical experiments that are similar to the criticality safety models. A principal challenge for crediting fission products (FP) in a burnup credit safety evaluation is the limited availability of relevant FP critical experiments for bias and bias uncertainty determination. This paper provides an evaluation of the available critical experiments that include FPs, along with bounding, burnup-dependent estimates of FP biases generated by combining energy dependent sensitivity data for a typical burnup credit application with the nuclear data uncertainty information distributed with SCALE 6. A method for determining separate bias and bias uncertainty values for individual FPs and illustrative results is presented. Finally, a FP bias calculation method based on data adjustment techniques and reactivity sensitivity coefficients calculated with the SCALE sensitivity/uncertainty tools and some typical results is presented. Using the methods described in this paper, the cross-section bias for a representative high-capacity spent fuel cask associated with the ENDF/B-VII nuclear data for 16 most important stable or near stable FPs is predicted to be no greater than 2% of the total worth of the 16 FPs, or less than 0.13 % k/k.

  9. Experiments on ocular tissue ablation at 5.3 and 6.0 {mu}m with the Los Alamos advanced FEL

    SciTech Connect

    Nguyen, D.C.; Ren, Q.; Hill, R.

    1995-12-31

    We investigated the ablation characteristics of a picosecond free-electron laser and compared its ablation effects on ocular tissues at 5.3 {mu}m and 6.0 {mu}m. The Advanced FEL at Los Alamos, operating in the wavelength range 4-6 {mu}m, was used for this study. The 10-{mu}s macropulse consisted of {approximately}1000 micropulses, each approximately 15 ps in length and separated from one another by 9.2 ns. The FEL beam was passed through a series of attenuator and focused to a 200-{mu}m spot in the sample with a 150-mm f.l. CaF{sub 2} lens. The energy in each macropulse ranged from 5 to 120 mJ. Five transplantable corneal-scleral buttons preserved in corneal storage media were used for this study. The tissue sample was positioned at the focused FEL beam for the ablation, and then fixed for histologic study. Corneal cuts made at 6.0 {mu}m revealed a well-defined ablation boundary. The measured lateral zone of the tissue damage was 11 {+-} 2 {mu}m. The integrity of the adjacent tissue was well maintained. By contrast, the ablation boundary of the corneal cuts made at 5.3 {mu}m appeared to be very disruptive. The collagen fiber near the ablation was thermally denatured and lost its organized structure. The lateral dimension of such effect extended out to 220 {mu}m beyond the intended cut into the surrounding tissues. We concluded that a short-pulsed laser operating at 6 {mu}m may be a potentially effective tool for cutting ocular tissues.

  10. Graphite and Beryllium Reflector Critical Assemblies of UO2 (Benchmark Experiments 2 and 3)

    SciTech Connect

    Margaret A. Marshall; John D. Bess

    2012-11-01

    INTRODUCTION A series of experiments was carried out in 1962-65 at the Oak Ridge National Laboratory Critical Experiments Facility (ORCEF) for use in space reactor research programs. A core containing 93.2 wt% enriched UO2 fuel rods was used in these experiments. The first part of the experimental series consisted of 252 tightly-packed fuel rods (1.27-cm triangular pitch) with graphite reflectors [1], the second part used 252 graphite-reflected fuel rods organized in a 1.506-cm triangular-pitch array [2], and the final part of the experimental series consisted of 253 beryllium-reflected fuel rods in a 1.506-cm-triangular-pitch configuration and in a 7-tube-cluster configuration [3]. Fission rate distribution and cadmium ratio measurements were taken for all three parts of the experimental series. Reactivity coefficient measurements were taken for various materials placed in the beryllium reflected core. All three experiments in the series have been evaluated for inclusion in the International Reactor Physics Experiment Evaluation Project (IRPhEP) [4] and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbooks, [5]. The evaluation of the first experiment in the series was discussed at the 2011 ANS Winter meeting [6]. The evaluations of the second and third experiments are discussed below. These experiments are of interest as benchmarks because they support the validation of compact reactor designs with similar characteristics to the design parameters for a space nuclear fission surface power systems [7].

  11. Determination of Critical Experiment Correlations Using the Sampler Sequence Within SCALE 6.2

    SciTech Connect

    Marshall, William BJ J; Rearden, Bradley T

    2015-01-01

    The validation of neutron transport methods used in nuclear criticality safety analyses is required by consensus American National Standards Institute/American Nuclear Society (ANSI/ANS) standards. In the last decade, there has been an increased interest in correlations among critical experiments used in validation that have shared physical attributes and which impact the independence of each measurement. The statistical methods included in many of the frequently cited guidance documents on performing validation calculations incorporate the assumption that all individual measurements are independent, so little guidance is available to practitioners on the topic. Typical guidance includes recommendations to select experiments from multiple facilities and experiment series in an attempt to minimize the impact of correlations or common-cause errors in experiments. Recent efforts have been made both to determine the magnitude of such correlations between experiments and to develop and apply methods for adjusting the bias and bias uncertainty to account for the correlations. This paper describes recent work performed at Oak Ridge National Laboratory using the Sampler sequence from the SCALE code system to develop experimental correlations using a Monte Carlo sampling technique. Sampler will be available for the first time with the release of SCALE 6.2, and a brief introduction to the methods used to calculate experiment correlations within this new sequence is presented in this paper. Techniques to utilize these correlations in the establishment of upper subcritical limits are the subject of a companion paper and will not be discussed here. Example experimental uncertainties and correlation coefficients are presented for a variety of low-enriched uranium water-moderated lattice experiments selected for use in a benchmark exercise by the Working Party on Nuclear Criticality Safety Subgroup on Uncertainty Analysis in Criticality Safety Analyses. The results include

  12. Los Alamos National Laboratory

    SciTech Connect

    Dogliani, Harold O

    2011-01-19

    The purpose of the briefing is to describe general laboratory technical capabilities to be used for various groups such as military cadets or university faculty/students and post docs to recruit into a variety of Los Alamos programs. Discussed are: (1) development and application of high leverage science to enable effeictive, predictable and reliability outcomes; (2) deter, detect, characterize, reverse and prevent the proliferation of weapons of mass destruction and their use by adversaries and terrorists; (3) modeling and simulation to define complex processes, predict outcomes, and develop effective prevention, response, and remediation strategies; (4) energetic materials and hydrodynamic testing to develop materials for precise delivery of focused energy; (5) materials cience focused on fundamental understanding of materials behaviors, their quantum-molecular properties, and their dynamic responses, and (6) bio-science to rapidly detect and characterize pathogens, to develop vaccines and prophylactic remedies, and to develop attribution forensics.

  13. Consolidated fuel reprocessing program: Criticality experiments with fast test reactor fuel pins in an organic moderator

    SciTech Connect

    Bierman, S.R.

    1986-12-01

    The results obtained in a series of criticality experiments performed as part of a joint program on criticality data development between the United States Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan are presented in this report along with a complete description of the experiments. The experiments involved lattices of Fast Test Reactor (FTR) fuel pins in an organic moderator mixture similar to that used in the solvent extraction stage of fuel reprocessing. The experiments are designed to provide data for direct comparison with previously performed experimental measurements with water moderated lattices of FTR fuel pins. The same lattice arrangements and FTR fuel pin types are used in these organic moderated experimental assemblies as were used in the water moderated experiments. The organic moderator is a mixture of 38 wt % tributylphosphate in a normal paraffin hydrocarbon mixture of C{sub 11}H{sub 24} to C{sub 15}H{sub 32} molecules. Critical sizes of 1054.8, 599.2, 301.8, 199.5 and 165.3 fuel pins were obtained respectively for organic moderated lattices having 0.761 cm, 0.968 cm, 1.242 cm, 1.537 cm and 1.935 cm square lattice pitches as compared to 1046.9, 571.9, 293.9, 199.7 and 165.1 fuel pins for the same lattices water moderated.

  14. The Experience of African Students Studying Nursing in the United States in Relation to Their Use of Critical Thinking

    ERIC Educational Resources Information Center

    Tyson, Donald Lee

    2012-01-01

    This qualitative study explores the critical thinking experiences of African nursing students enrolled in several universities in the U.S. Using a semi-structured interview approach, twelve African students discussed their experiences using and learning a western critical thinking approach, as well as described their educational experiences in…

  15. Criticality experiments with mixed oxide fuel pin arrays in plutonium-uranium nitrate solution

    SciTech Connect

    Lloyd, R.C. ); Smolen, G.R. )

    1988-08-01

    A series of critical experiments was completed with mixed plutonium-uranium solutions having a Pu/(Pu + U) ratio of approximately 0.22 in a boiler tube-type lattice assembly. These experiments were conducted as part of the Criticality Data Development Program between the United States Department of Energy (USDOE) and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. A complete description of the experiments and data are included in this report. The experiments were performed with an array of mixed oxide fuel pins in aqueous plutonium-uranium solutions. The fuel pins were contained in a boiler tube-type tank and arranged in a 1.4 cm square pitch array which resembled cylindrical geometry. One experiment was perfomed with the fuel pins removed from the vessel. The experiments were performed with a water reflector. The concentration of the solutions in the boiler tube-type tank was varied from 4 to 468 g (Pu + U)/liter. The ratio of plutonium to total heavy metal (plutonium plus uranium) was approximately 0.22 for all experiments.

  16. Planning the Unplanned Experiment: Assessing the Efficacy of Standards for Safety Critical Software

    NASA Technical Reports Server (NTRS)

    Graydon, Patrick J.; Holloway, C. Michael

    2015-01-01

    We need well-founded means of determining whether software is t for use in safety-critical applications. While software in industries such as aviation has an excellent safety record, the fact that software aws have contributed to deaths illustrates the need for justi ably high con dence in software. It is often argued that software is t for safety-critical use because it conforms to a standard for software in safety-critical systems. But little is known about whether such standards `work.' Reliance upon a standard without knowing whether it works is an experiment; without collecting data to assess the standard, this experiment is unplanned. This paper reports on a workshop intended to explore how standards could practicably be assessed. Planning the Unplanned Experiment: Assessing the Ecacy of Standards for Safety Critical Software (AESSCS) was held on 13 May 2014 in conjunction with the European Dependable Computing Conference (EDCC). We summarize and elaborate on the workshop's discussion of the topic, including both the presented positions and the dialogue that ensued.

  17. Los Alamos National Laboratory strategic directions

    SciTech Connect

    Hecker, S.

    1995-10-01

    It is my pleasure to welcome you to Los Alamos. I like the idea of bringing together all aspects of the research community-defense, basic science, and industrial. It is particularly important in today`s times of constrained budgets and in fields such as neutron research because I am convinced that the best science and the best applications will come from their interplay. If we do the science well, then we will do good applications. Keeping our eye focused on interesting applications will spawn new areas of science. This interplay is especially critical, and it is good to have these communities represented here today.

  18. MCNP benchmark analyses of critical experiments for the Space Nuclear Thermal Propulsion program

    SciTech Connect

    Selcow, E.C.; Cerbone, R.J.; Ludewig, H.; Mughabghab, S.F.; Schmidt, E.; Todosow, M. ); Parma, E.J. ); Ball, R.M.; Hoovler, G.S. )

    1993-01-15

    Benchmark analyses have been performed of Particle Bed Reactor (PBR) critical experiments (CX) using the MCNP radiation transport code. The experiments have been conducted at the Sandia National Laboratory reactor facility in support of the Space Nuclear Thermal Propulsion (SNTP) program. The test reactor is a nineteen element water moderated and reflected thermal system. A series of integral experiments have been carried out to test the capabilities of the radiation transport codes to predict the performance of PBR systems. MCNP was selected as the preferred radiation analysis tool for the benchmark experiments. Comparison between experimental and calculational results indicate close agreement. This paper describes the analyses of benchmark experiments designed to quantify the accuracy of the MCNP radiation transport code for predicting the performance characteristics of PBR reactors.

  19. MCNP benchmark analyses of critical experiments for the Space Nuclear Thermal Propulsion program

    SciTech Connect

    Selcow, E.C.; Cerbone, R.J.; Ludewig, H.; Mughabghab, S.F.; Schmidt, E.; Todosow, M.; Parma, E.J.; Ball, R.M.; Hoovler, G.S.

    1993-06-01

    Benchmark analyses have been performed of Particle Bed Reactor (PBR) critical experiments (CX) using the MCNP radiation transport code. The experiments have been conducted at the Sandia National Laboratory reactor facility in support of the Space Nuclear Thermal Propulsion (SNTP) program. The test reactor is a nineteen element water moderated and reflected thermal system. A series of integral experiments have been carried out to test the capabilities of the radiation transport codes to predict the performance of PBR systems. MCNP was selected as the preferred radiation analysis tool for the benchmark experiments. Comparison between experimental and calculational results indicate very good agreement. This paper describes the analyses of benchmark experiments designed to quantify the accuracy of the MCNP radiation transport code for predicting the performance characteristics of PBR reactors.

  20. Los Alamos National Laboratory Overview

    SciTech Connect

    Neu, Mary

    2010-06-02

    Mary Neu, Associate Director for Chemistry, Life and Earth Sciences at Los Alamos National Laboratory, delivers opening remarks at the "Sequencing, Finishing, Analysis in the Future" meeting in Santa Fe, NM

  1. Evaluation of the French Haut Taux de Combustion (HTC) Critical Experiment Data

    SciTech Connect

    Mueller, Don; Elam, Karla Riggle; Fox, Patricia B

    2008-09-01

    In the 1980s, a series of critical experiments referred to as the Haut Taux de Combustion (HTC) experiments was conducted by the Institut de Radioprotection et de Surete Nucleaire (IRSN) at the experimental criticality facility in Valduc, France. The plutonium-to- uranium ratio and the isotopic compositions of both the uranium and plutonium used in the simulated fuel rods were designed to be similar to what would be found in a typical pressurized-water reactor fuel assembly that initially had an enrichment of 4.5 wt% {sup 235}U and was burned to 37,500 MWd/MTU. The fuel material also includes {sup 241}Am, which is present due to the decay of {sup 241}Pu. The HTC experiments include configurations designed to simulate fuel handling activities, pool storage, and transport in casks constructed of thick lead or steel. Rights of use for the HTC experiment data were purchased under an agreement that limits release of the information. Consequently, a detailed and complete description of the experiments is not presented in this report. This report discusses evaluation of the four HTC data reports, modeling of the experiments, sensitivity and uncertainty analysis, and upper subcritical limit (USL) calculation. The report also presents some conclusions and recommendations concerning use of the HTC experiment data for burnup credit applications. The similarity of the HTC experiments with PWR spent nuclear fuel has been quantified using sensitivity/uncertainty analysis, confirming that the HTC experiments are significantly more applicable to the validation of burnup credit calculations than other available mixed-oxide (MOX) experiments. The HTC experiments were designed and executed with a high level of rigor, resulting in experimental uncertainties that are lower than many of the earlier MOX experiments. The HTC data reports, together with information provided in this report, provide sufficient data to allow for either detailed or simplified computational models to be

  2. Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers

    SciTech Connect

    Rothe, R.E.

    1996-09-30

    A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution`s concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the `Poisoned Tube Tank` because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service.

  3. Dry critical experiments and analyses performed in support of the Topaz-2 Safety Program

    NASA Astrophysics Data System (ADS)

    Pelowitz, D. B.; Sapir, J.; Glushkov, E. S.; Ponomarev-Stepnoi, N. N.; Bubelev, V. G.; Kompanietz, G. B.; Krutov, A. M.; Polyakov, D. N.; Loynstev, V. A.

    In December 1991, the Strategic Defense Initiative Organization decided to investigate the possibility of launching a Russian Topaz-2 space nuclear power system. Functional safety requirements developed for the Topaz mission mandated that the reactor remain subcritical when flooded and immersed in water. Initial experiments and analyses performed in Russia and the United States indicated that the reactor could potentially become supercritical in several water- or sand-immersion scenarios. Consequently, a series of critical experiments was performed on the Narciss M-II facility at the Kurchatov Institute to measure the reactivity effects of water and sand immersion, to quantify the effectiveness of reactor modifications proposed to preclude criticality, and to benchmark the calculational methods and nuclear data used in the Topaz-2 safety analyses. In this paper we describe the Narciss M-II experimental configurations along with the associated calculational models and methods. We also present and compare the measured and calculated results for the dry experimental configurations.

  4. Dry critical experiments and analyses performed in support of the TOPAZ-2 safety program

    NASA Astrophysics Data System (ADS)

    Pelowitz, Denise B.; Sapir, Joseph; Glushkov, Evgeny S.; Ponomarev-Stepnoi, Nikolai N.; Bubelev, Vladimir G.; Kompanietz, George B.; Krutov, Aleksei M.; Polyakov, Dmitry N.; Lobynstev, Viacheslav A.

    1995-01-01

    In December 1991, the Strategic Defense Initiative Organization decided to investigate the possibility of launching a Russian Topaz-2 space nuclear power system. Functional safety requirements developed for the Topaz mission mandated that the reactor remain subcritical when flooded and immersed in water. Initial experiments and analyses performed in Russia and the United States indicated that the reactor could potentially become supercritical in several water- or sand-immersion scenarios. Consequently, a series of critical experiments was performed on the Narciss M-II facility at the Kurchatov Institute to measure the reactivity effects of water and sand immersion, to quantify the effectiveness of reactor modifications proposed to preclude criticality, and to benchmark the calculational methods and nuclear data used in the Topaz-2 safety analyses. In this paper we describe the Narciss M-II experimental configurations along with the associated calculational models and methods. We also present and compare the measured and calculated results for the dry experimental configurations.

  5. SCALE TSUNAMI Analysis of Critical Experiments for Validation of 233U Systems

    SciTech Connect

    Mueller, Don; Rearden, Bradley T

    2009-01-01

    Oak Ridge National Laboratory (ORNL) staff used the SCALE TSUNAMI tools to provide a demonstration evaluation of critical experiments considered for use in validation of current and anticipated operations involving {sup 233}U at the Radiochemical Development Facility (RDF). This work was reported in ORNL/TM-2008/196 issued in January 2009. This paper presents the analysis of two representative safety analysis models provided by RDF staff.

  6. Real-time reinforcement learning by sequential Actor-Critics and experience replay.

    PubMed

    Wawrzyński, Paweł

    2009-12-01

    Actor-Critics constitute an important class of reinforcement learning algorithms that can deal with continuous actions and states in an easy and natural way. This paper shows how these algorithms can be augmented by the technique of experience replay without degrading their convergence properties, by appropriately estimating the policy change direction. This is achieved by truncated importance sampling applied to the recorded past experiences. It is formally shown that the resulting estimation bias is bounded and asymptotically vanishes, which allows the experience replay-augmented algorithm to preserve the convergence properties of the original algorithm. The technique of experience replay makes it possible to utilize the available computational power to reduce the required number of interactions with the environment considerably, which is essential for real-world applications. Experimental results are presented that demonstrate that the combination of experience replay and Actor-Critics yields extremely fast learning algorithms that achieve successful policies for non-trivial control tasks in considerably short time. Namely, the policies for the cart-pole swing-up [Doya, K. (2000). Reinforcement learning in continuous time and space. Neural Computation, 12(1), 219-245] are obtained after as little as 20 min of the cart-pole time and the policy for Half-Cheetah (a walking 6-degree-of-freedom robot) is obtained after four hours of Half-Cheetah time. PMID:19523786

  7. MCNP analysis of PNL split-table critical experiments containing mixed-oxide fuels

    SciTech Connect

    Abdurrahman, N.M.; Yavuz, M.; Radulescu, G.

    1997-12-01

    Pacific Northwest Laboratory (PNL) Split-Table Critical experiments containing mixed-oxide (MOX) fuels for various core configurations are studied using MCNP4A with the ENDF/B-VI continuous-energy library. These experiments were performed to provide necessary technical information and experimental criticality data that would serve as benchmark data in support of the liquid-metal fast breeder reactor program. Because of the current interest in the utilization of weapons-grade plutonium in the form of MOX fuel in light water reactors, such experimental data are extremely important for checking the performance of the modem computational tools. The {sup 239}Pu content in plutonium of the PNL MOX fuels is {approximately}91 wt%, which is very close to that of the weapons-grade {sup 239}Pu. The MOX fuels used in these critical experiments consist of 30.0, 14.62, and 7.89 wt% Pu and N{sub H}/(N{sub Pu} + Nu) moderation ratios (MRs) of 47.4, 30.6, and 51.8, respectively.

  8. Planning the Unplanned Experiment: Towards Assessing the Efficacy of Standards for Safety-Critical Software

    NASA Technical Reports Server (NTRS)

    Graydon, Patrick J.; Holloway, C. M.

    2015-01-01

    Safe use of software in safety-critical applications requires well-founded means of determining whether software is fit for such use. While software in industries such as aviation has a good safety record, little is known about whether standards for software in safety-critical applications 'work' (or even what that means). It is often (implicitly) argued that software is fit for safety-critical use because it conforms to an appropriate standard. Without knowing whether a standard works, such reliance is an experiment; without carefully collecting assessment data, that experiment is unplanned. To help plan the experiment, we organized a workshop to develop practical ideas for assessing software safety standards. In this paper, we relate and elaborate on the workshop discussion, which revealed subtle but important study design considerations and practical barriers to collecting appropriate historical data and recruiting appropriate experimental subjects. We discuss assessing standards as written and as applied, several candidate definitions for what it means for a standard to 'work,' and key assessment strategies and study techniques and the pros and cons of each. Finally, we conclude with thoughts about the kinds of research that will be required and how academia, industry, and regulators might collaborate to overcome the noted barriers.

  9. Nuclear criticality research at the University of New Mexico

    SciTech Connect

    Busch, R.D.

    1997-06-01

    Two projects at the University of New Mexico are briefly described. The university`s Chemical and Nuclear Engineering Department has completed the final draft of a primer for MCNP4A, which it plans to publish soon. The primer was written to help an analyst who has little experience with the MCNP code to perform criticality safety analyses. In addition, the department has carried out a series of approach-to-critical experiments on the SHEBA-II, a UO{sub 2}F{sub 2} solution critical assembly at Los Alamos National Laboratory. The results obtained differed slightly from what was predicted by the TWODANT code.

  10. Analysis of Godiva-IV delayed-critical and static super-prompt-critical conditions

    SciTech Connect

    Mosteller, Russell D; Goda, Joetta M

    2009-01-01

    Super-prompt-critical burst experiments were conducted on the Godiva-IV assembly at Los Alamos National Laboratory from the 1960s through 2005. Detailed and simplified benchmark models have been constructed for four delayed-critical experiments and for the static phase of a super-prompt-critical burst experiment. In addition, a two-dimensional cylindrical model has been developed for the super-prompt-critical condition. Criticality calculations have been performed for all of those models with four modern nuclear data libraries: ENDFIB-VI, ENDF/8-VII.0, JEFF-3.1 , and JENDL-3.3. Overall, JENDL-3.3 produces the best agreement with the reference values for k{sub eff}.

  11. Critical Experiments With Aqueous Solutions of {sup 233}UO{sub 2}(NO{sub 3}){sub 2}

    SciTech Connect

    Thomas, J.T.

    2001-05-17

    This report provides the critical experimenter's interpretations and descriptions of informal critical experiment logbook notes and associated information (e.g., experimental equipment designs/sketches, chemical and isotopic analyses, etc.) for the purpose of formally documenting the results of critical experiments performed in the late 1960s at the Oak Ridge Critical Experiments Facility. The experiments were conducted with aqueous solutions of 97.6 wt % {sup 233}U uranyl nitrate having uranium densities varying between about 346 g U/l and 45 g U/l. Criticality was achieved with single simple units (e.g., cylinders and spheres) and with spaced subcritical simple cylindrical units arranged in unreflected, water-reflected, and polyethylene reflected critical arrays.

  12. Critical Experiments With Aqueous Solutions of {sup 233}UO{sub 2}(NO{sub ;3}){sub 2}

    SciTech Connect

    Thomas, J T

    2001-05-17

    This report provides the critical experimenter's interpretations and descriptions of informal critical experiment logbook notes and associated information (e.g., experimental equipment designs/sketches, chemical and isotopic analyses, etc.) for the purpose of formally documenting the results of critical experiments performed in the late 1960s at the Oak Ridge Critical Experiments Facility. The experiments were conducted with aqueous solutions of 97.6 wt % {sup 233}U uranyl nitrate having uranium densities varying between about 346 g U/l and 45 g U/l. Criticality was achieved with single simple units (e.g., cylinders and spheres) and with spaced subcritical simple cylindrical units arranged in unreflected, water-reflected, and polyethylene reflected critical arrays.

  13. Correlation between Knowledge, Experience and Common Sense, with Critical Thinking Capability of Medical Faculty's Students at Indonesia Christian University

    ERIC Educational Resources Information Center

    Nadeak, Bernadetha

    2015-01-01

    This research discusses correlation between knowledge, experience and common sense with critical thinking of Medical Faculty's Student. As to the objective of this research is to find the correlation between knowledge, experience and common sense with critical thinking of Medical Faculty's Students at Christian University of Indonesia. It is…

  14. Women, Poverty, and Educational Success: A Critical Exploration of Low-Income Women's Experience in Community Colleges

    ERIC Educational Resources Information Center

    Barry, Kate R.

    2012-01-01

    The purpose of this study is to critically explore low-income women's experience as they negotiate post secondary education in community colleges. Three research questions explore the context through which low-income women have entered the college experience, what that experience is like for them, and how the community college experience has…

  15. Charge exchange contamination of CRIT-II barium CIV experiment. [critical ionization velocity in ionosphere

    NASA Technical Reports Server (NTRS)

    Swenson, G. R.; Mende, S. B.; Meyerott, R. E.; Rairden, R. L.

    1991-01-01

    Experiments have been recently performed which attempted to confirm critical ionization velocity (CIV) ionization by deploying chemicals at high velocity in the ionosphere. Specifically, the CRIT-II rocket performed a barium release in the ionosphere, where observations of Ba(+) resonant emissions following the release are believed to have resulted from the CIV process. Calculations are presented which suggest a significant fraction (if not all) of the Ba(+) observed likely resulted from charge exchange with the thermosphere ions and not through CIV processes. The results presented here are pertinent to other CIV experiments performed in the ionosphere. It is recommended that laboratory measurements should be made of the charge exchange cross section between O(+) and Ba as well as other metal vapors used in CIV experiments.

  16. 'Visual' parsing can be taught quickly without visual experience during critical periods.

    PubMed

    Reich, Lior; Amedi, Amir

    2015-01-01

    Cases of invasive sight-restoration in congenital blind adults demonstrated that acquiring visual abilities is extremely challenging, presumably because visual-experience during critical-periods is crucial for learning visual-unique concepts (e.g. size constancy). Visual rehabilitation can also be achieved using sensory-substitution-devices (SSDs) which convey visual information non-invasively through sounds. We tested whether one critical concept--visual parsing, which is highly-impaired in sight-restored patients--can be learned using SSD. To this end, congenitally blind adults participated in a unique, relatively short (~70 hours), SSD-'vision' training. Following this, participants successfully parsed 2D and 3D visual objects. Control individuals naïve to SSDs demonstrated that while some aspects of parsing with SSD are intuitive, the blind's success could not be attributed to auditory processing alone. Furthermore, we had a unique opportunity to compare the SSD-users' abilities to those reported for sight-restored patients who performed similar tasks visually, and who had months of eyesight. Intriguingly, the SSD-users outperformed the patients on most criteria tested. These suggest that with adequate training and technologies, key high-order visual features can be quickly acquired in adulthood, and lack of visual-experience during critical-periods can be somewhat compensated for. Practically, these highlight the potential of SSDs as standalone-aids or combined with invasive restoration approaches. PMID:26482105

  17. 'Visual’ parsing can be taught quickly without visual experience during critical periods

    PubMed Central

    Reich, Lior; Amedi, Amir

    2015-01-01

    Cases of invasive sight-restoration in congenital blind adults demonstrated that acquiring visual abilities is extremely challenging, presumably because visual-experience during critical-periods is crucial for learning visual-unique concepts (e.g. size constancy). Visual rehabilitation can also be achieved using sensory-substitution-devices (SSDs) which convey visual information non-invasively through sounds. We tested whether one critical concept – visual parsing, which is highly-impaired in sight-restored patients – can be learned using SSD. To this end, congenitally blind adults participated in a unique, relatively short (~70 hours), SSD-‘vision’ training. Following this, participants successfully parsed 2D and 3D visual objects. Control individuals naïve to SSDs demonstrated that while some aspects of parsing with SSD are intuitive, the blind’s success could not be attributed to auditory processing alone. Furthermore, we had a unique opportunity to compare the SSD-users’ abilities to those reported for sight-restored patients who performed similar tasks visually, and who had months of eyesight. Intriguingly, the SSD-users outperformed the patients on most criteria tested. These suggest that with adequate training and technologies, key high-order visual features can be quickly acquired in adulthood, and lack of visual-experience during critical-periods can be somewhat compensated for. Practically, these highlight the potential of SSDs as standalone-aids or combined with invasive restoration approaches. PMID:26482105

  18. From idealistic helper to enterprising learner: critical reflections on personal development through experiences from Afghanistan.

    PubMed

    Wickford, Jenny; Rosberg, Susanne

    2012-05-01

    There is little written about the cultural, social, and ethical challenges encountered by physiotherapists engaging in development work. This article takes a critical perspective on what it means to engage in development work as an expatriate physiotherapist, through a self-critical reflection on experiences from Afghanistan. The field notes from an ethnographic study of a development project conducted in Afghanistan were analysed to explore the transformative process of personal and professional development of the development worker. The critical reflective process entailed a change in meaning perspective, described as a shift from the position of an Idealistic Helper to an Enterprising Learner. Of importance in this process were "disorienting dilemmas" that challenged personal perceptions. Critical reflection over such dilemmas led to deeper understanding facilitating the process of change. The essential lesson learned is that the baseline for understanding others is an understanding of one's own meaning perspectives and manner of participation in relation to others and their context. The insights gained have implications for physiotherapists working in development contexts, for other development workers, and for physiotherapists working with patients in clinical practice in a nondevelopment context. Exploring how to collaborate in development contexts could be done using reflective groups with expatriate and local physiotherapists and/or patients. This could lead to greater understanding of oneself, each other, and the local context. PMID:22047471

  19. Recollections of a very junior physicist at Los Alamos, 1944-1946

    NASA Astrophysics Data System (ADS)

    French, Anthony P.

    2008-04-01

    The author came to Los Alamos as a member of the British Mission after two years of making fission cross section measurements at the Cavendish Laboratory. He worked in a group headed by Egon Bretscher in Enrico Fermi's F Division. The talk presents his personal memories and experiences at Los Alamos as compared to his life and work in wartime Britain.

  20. Participation in ICZM initiatives: critical aspects and lessons learnt from the Mediterranean and Black Sea experiences.

    PubMed

    Soriani, Stefano; Buono, Fabrizia; Tonino, Marco; Camuffo, Monica

    2015-03-15

    Public participation is recognized as a necessary tool to ensure a successful implementation of Integrated Coastal Zone Management (ICZM) strategies and plans. This paper, based on the experiences carried out in the Mediterranean and in the Black Sea within the EU FP7 project PEGASO, presents some critical aspects and lessons learnt regarding participation in ICZM projects. The research shows that data availability, the complexity of data interpretation, an inadequate legal and cultural framework and the difficulties in promoting integration of all the components of coastal management within short term projects are all elements that if not properly considered since the beginning of the participatory process may hinder public participation effectiveness. Moreover the definition of the spatial scale of coastal phenomenon as well as the discrepancy between the local scale of coastal governance and the complex multi-scale nature of coastal systems remain highly critical aspects to be addressed. PMID:25659448

  1. Non-solar UV produced ions observed optically from the 'Crit I' critical velocity ionization experiment

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Rees, D.; Valenzuela, A.; Brenning, N.

    1990-01-01

    A critical velocity ionization experiment was carried out with a heavily instrumented rocket launched from Wallops Island on May 13, 1986. Two neutral barium beams were created by explosive shaped charges released from the rocket and detonated at 48 deg to B at altitudes near 400 km and below the solar UV cutoff. Critical velocity ionization was expected to form a detectable ion jet along the release field line, but, instead, an ion cloud of fairly uniform intensity was observed stretching from the release field line across to where the neutral barium jet reached sunlight. The process creating these ions must have been present from the time of the release; the efficiency is estimated to be equivalent to an ionization time constant of 1800 sec. This ionization is most likely from collisions between the neutral barium jet and the ambient atmospheric oxygen, and, if so, the cross section for collisional ionization is 9 x 10 to the -18th sq cm.

  2. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory`s Source Region Program. Appendix D: Ionospheric measurements for IVEs

    SciTech Connect

    Fitzgerald, T.J.; Carlos, R.C.; Argo, P.E.

    1993-01-21

    As part of the integrated verification experiment (IVE), we deployed a network of hf ionospheric sounders to detect the effects of acoustic waves generated by surface ground motion following underground nuclear tests at the Nevada Test Site. The network sampled up to four geographic locations in the ionosphere from almost directly overhead of the surface ground zero out to a horizontal range of 60 km. We present sample results for four of the IVEs: Misty Echo, Texarkana, Mineral Quarry, and Bexar.

  3. The critical warzone experiences (CWE) scale: initial psychometric properties and association with PTSD, anxiety, and depression.

    PubMed

    Kimbrel, Nathan A; Evans, Lianna D; Patel, Amee B; Wilson, Laura C; Meyer, Eric C; Gulliver, Suzy B; Morissette, Sandra B

    2014-12-30

    The objective of the present research was to develop and evaluate a critical warzone experiences (CWE) scale for use with Iraq/Afghanistan veterans. The psychometric properties of the CWE were evaluated across three independent samples of Iraq/Afghanistan veterans. Despite its brevity (7 items), the CWE exhibited good internal consistency (average α =0.83), good temporal stability (1-year test-retest reliability=0.73), good concurrent validity with lengthier measures of warzone experiences (average r=0.74), and a clear unidimensional factor structure (average factor loading=0.69). Study 2 confirmed the CWE׳s factor structure through confirmatory factor analysis, and structural equation modeling demonstrated a strong association between CWE and post-deployment mental health, β =0.49, p<0.001. Study 3 provided further support for the predictive validity of the CWE by demonstrating that it was associated with PTSD diagnosis, clinician-rated PTSD symptom severity, and global functional impairment in an independent sample of Iraq/Afghanistan veterans (average r=0.59). While replication of these findings in more diverse samples is needed, the preliminary evidence from these studies indicates that the CWE is a brief, reliable, and valid measure of critical warzone experiences among Iraq/Afghanistan war veterans. PMID:25238984

  4. Validation of KENO-VI: A comparison with hexagonal lattice light-water-reactor critical experiments

    SciTech Connect

    Lichtenwalter, J.J.

    1998-06-01

    The KENO-VI Monte Carlo code, released with Version 4.3 of the SCALE Code System, provides the capability to model more complex geometries than previously allowed by KENO-V.a. One significant improvement is the simplistic specification of hexprism unit cells and hexagonal arrays, an arduous task to complete in KENO-V.a. This report documents the validation of KENO-VI against 30 critical experiments consisting of low enriched uranium, light water reactor (LWR) fuel rods in hexagonal lattices with no poisons. The reference, enrichment, pitch, cladding, and core identification of the experiments are given. The results indicate that KENO-VI accurately calculates these critical experiments, with a bias of {minus}0.51% for the 238 group cross section library and {minus}0.24% for the 44 group cross section library. If these biases are properly taken into account, the KENO-VI code can be used with confidence for the design and safety analysis of storage and transportation systems of similar LWR type fuels.

  5. Critical experiments on single-unit spherical plutonium geometries reflected and moderated by oil

    SciTech Connect

    Rothe, R.E.

    1997-05-01

    Experimental critical configurations are reported for several dozen spherical and hemispherical single-unit assemblies of plutonium metal. Most were solid but many were hollow-centered, thick, shell-like geometries. All were constructed of nested plutonium (mostly {sup 2139}Pu) metal hemispherical shells. Three kinds of critical configurations are reported. Two required interpolation and/or extrapolation of data to obtain the critical mass because reflector conditions were essentially infinite. The first finds the plutonium essentially fully reflected by a hydrogen-rich oil; the second is essentially unreflected. The third kind reports the critical oil reflector height above a large plutonium metal assembly of accurately known mass (no interpolation required) when that mass was too great to permit full oil reflection. Some configurations had thicknesses of mild steel just outside the plutonium metal, separating it from the oil. These experiments were performed at the Rocky Flats Critical Mass Laboratory in the late 1960s. They have not been published in a form suitable for benchmark-quality comparisons against state-of-the-art computational techniques until this paper. The age of the data and other factors lead to some difficulty in reconstructing aspects of the program and may, in turn, decrease confidence in certain details. Whenever this is true, the point is acknowledged. The plutonium metal was alpha-phase {sup 239}Pu containing 5.9 wt-% {sup 240}Pu. All assemblies were formed by nesting 1.667-mm-thick (nominal) bare plutonium metal hemispherical shells, also called hemishells, until the desired configuration was achieved. Very small tolerance gaps machined into radial dimensions reduced the effective density a small amount in all cases. Steel components were also nested hemispherical shells; but these were nominally 3.333-mm thick. Oil was used as the reflector because of its chemical compatibility with plutonium metal.

  6. Long-Term Soil Experiments: A Key to Managing Earth's Rapidly Changing Critical Zones

    NASA Astrophysics Data System (ADS)

    Richter, D., Jr.

    2014-12-01

    In a few decades, managers of Earth's Critical Zones (biota, humans, land, and water) will be challenged to double food and fiber production and diminish adverse effects of management on the wider environment. To meet these challenges, an array of scientific approaches is being used to increase understanding of Critical Zone functioning and evolution, and one amongst these approaches needs to be long-term soil field studies to move us beyond black boxing the belowground Critical Zone, i.e., to further understanding of processes driving changes in the soil environment. Long-term soil experiments (LTSEs) provide direct observations of soil change and functioning across time scales of decades, data critical for biological, biogeochemical, and environmental assessments of sustainability; for predictions of soil fertility, productivity, and soil-environment interactions; and for developing models at a wide range of temporal and spatial scales. Unfortunately, LTSEs globally are not in a good state, and they take years to mature, are vulnerable to loss, and even today remain to be fully inventoried. Of the 250 LTSEs in a web-based network, results demonstrate that soils and belowground Critical Zones are highly dynamic and responsive to human management. The objective of this study is to review the contemporary state of LTSEs and consider how they contribute to three open questions: (1) can soils sustain a doubling of food production in the coming decades without further impinging on the wider environment, (2) how do soils interact with the global C cycle, and (3) how can soil management establish greater control over nutrient cycling. While LTSEs produce significant data and perspectives for all three questions, there is on-going need and opportunity for reviews of the long-term soil-research base, for establishment of an efficiently run network of LTSEs aimed at sustainability and improving management control over C and nutrient cycling, and for research teams that

  7. Undergraduate experiment in critical phenomena. II. The coexistence curve of a binary fluid mixture

    NASA Astrophysics Data System (ADS)

    Ngubane, S. B.; Jacobs, D. T.

    1986-06-01

    An undergraduate experiment is described that uses meniscus heights to determine the coexistence curve of a binary fluid mixture. The data can be obtained with a minimum of equipment and yield results that are easily interpreted by the theory also presented. Data taken on the binary liquid mixture methanol-isooctane are presented and analyzed. The critical temperature and composition were found to be (42.5±0.5) °C and (67.3±0.2)% by volume isooctane, respectively.

  8. Acoustic Experiment to Measure the Bulk Viscosity of Near-Critical Xenon in Microgravity

    NASA Technical Reports Server (NTRS)

    Gillis, K. A.; Shinder, I.; Moldover, M. R.; Zimmerli, G. A.

    2002-01-01

    We plan a rigorous test of the theory of dynamic scaling by accurately measuring the bulk viscosity of xenon in microgravity 50 times closer to the critical temperature T(sub c) than previous experiments. The bulk viscosity zeta (or "second viscosity" or "dilational viscosity") will be determined by measuring the attenuation length of sound alpha lambda and also measuring the frequency-dependence of the speed of sound. For these measurements, we developed a unique Helmholtz resonator and specialized electro-acoustic transducers. We describe the resonator, the transducers, their performance on Earth, and their expected performance in microgravity.

  9. Analysis of a boron-carbide-drum-controlled critical reactor experiment

    NASA Technical Reports Server (NTRS)

    Mayo, W. T.

    1972-01-01

    In order to validate methods and cross sections used in the neutronic design of compact fast-spectrum reactors for generating electric power in space, an analysis of a boron-carbide-drum-controlled critical reactor was made. For this reactor the transport analysis gave generally satisfactory results. The calculated multiplication factor for the most detailed calculation was only 0.7-percent Delta k too high. Calculated reactivity worth of the control drums was $11.61 compared to measurements of $11.58 by the inverse kinetics methods and $11.98 by the inverse counting method. Calculated radial and axial power distributions were in good agreement with experiment.

  10. Space, the final frontier: A critical review of recent experiments performed in microgravity.

    PubMed

    Vandenbrink, Joshua P; Kiss, John Z

    2016-02-01

    Space biology provides an opportunity to study plant physiology and development in a unique microgravity environment. Recent space studies with plants have provided interesting insights into plant biology, including discovering that plants can grow seed-to-seed in microgravity, as well as identifying novel responses to light. However, spaceflight experiments are not without their challenges, including limited space, limited access, and stressors such as lack of convection and cosmic radiation. Therefore, it is important to design experiments in a way to maximize the scientific return from research conducted on orbiting platforms such as the International Space Station. Here, we provide a critical review of recent spaceflight experiments and suggest ways in which future experiments can be designed to improve the value and applicability of the results generated. These potential improvements include: utilizing in-flight controls to delineate microgravity versus other spaceflight effects, increasing scientific return via next-generation sequencing technologies, and utilizing multiple genotypes to ensure results are not unique to one genetic background. Space experiments have given us new insights into plant biology. However, to move forward, special care should be given to maximize science return in understanding both microgravity itself as well as the combinatorial effects of living in space. PMID:26795156

  11. Interpretation of the electric fields measured in an ionospheric critical ionization velocity experiment

    NASA Technical Reports Server (NTRS)

    Brenning, N.; Faelthammar, C.-G.; Marklund, G.; Haerendel, G.; Kelley, M. C.; Pfaff, R.

    1991-01-01

    The quasi-dc electric fields measured in the CRIT I ionospheric release experiment are studied. In the experiment, two identical barium shaped charges were fired toward a main payload, and three-dimensional measurements of the electric field inside the streams were made. The relevance of proposed mechanisms for electron heating in the critical ionization velocity (CIV) mechanism is addressed. It is concluded that both the 'homogeneous' and the 'ionizing front' models probably are valid, but in different parts of the streams. It is also possible that electrons are directly accelerated by a magnetic field-aligned component of the electric field. The coupling between the ambient ionosphere and the ionized barium stream is more complicated that is usually assumed in CIV theories, with strong magnetic-field-aligned electric fields and probably current limitation as important processes.

  12. Plasma-wall interaction data needs critical to a Burning Core Experiment (BCX)

    SciTech Connect

    Not Available

    1985-11-01

    The Division of Development and Technology has sponsored a four day US-Japan workshop ''Plasma-Wall Interaction Data Needs Critical to a Burning Core Experiment (BCX)'', held at Sandia National Laboratories, Livermore, California on June 24 to 27, 1985. The workshop, which brought together fifty scientists and engineers from the United States, Japan, Germany, and Canada, considered the plasma-material interaction and high heat flux (PMI/HHF) issues for the next generation of magnetic fusion energy devices, the Burning Core Experiment (BCX). Materials options were ranked, and a strategy for future PMI/HHF research was formulated. The foundation for international collaboration and coordination of this research was also established. This volume contains the last three of the five technical sessions. The first of the three is on plasma materials interaction issues, the second is on research facilities and the third is from smaller working group meetings on graphite, beryllium, advanced materials and future collaborations.

  13. Defect printability of alternating phase-shift mask: a critical comparison of simulation and experiment

    NASA Astrophysics Data System (ADS)

    Ozawa, Ken; Komizo, Tooru; Kikuchi, Koji; Ohnuma, Hidetoshi; Kawahira, Hiroichi

    2002-07-01

    An alternative phase shift mask (alt-PSM) is a promising device for extending optical lithography to finer design rules. There have been few reports, however, on the mask's ability to identify phase defects. We report here an alt-PSM of a dual-trench type for KrF exposure, with programmed quartz defects used to evaluate defect printability by measuring aerial images with a Zeiss MSM100 measuring system. The experimental results are simulated using the TEMPEST program. First, a critical comparison of the simulation and the experiment is conducted. The actual measured topography of quartz defects are used in the simulation. Moreover, a general simulation study on defect printability using an alt-PSM for ArF exposure is conducted. The defect dimensions, which produce critical CD errors are determined by simulation that takes into account the full 3-dimensional structure of phase defects as well as a simplified structure. The critical dimensions of an isolated defect identified by the alt-PSM of a single-trench type for ArF exposure are 240 nm in bottom diameter and 50 degrees in height (phase) for the cylindrical shape and 240 nm in bottom diameter and 90 degrees in height (phase) for the rotating trapezoidal shape, where the CD error limit is +/- 5%.

  14. Pathways and pipelines: Self-reported critical experiences for expert and novice geologists

    NASA Astrophysics Data System (ADS)

    LaDue, N.; Pacheco, H. A.

    2011-12-01

    The recruitment and retention of geology students has received attention due to pressure from industry to replenish an aging workforce nearing retirement (Gonzales and Keane, 2010). Thorough, qualitative studies have been conducted using critical incident methodology to understand what experiences cause various groups of people to choose careers in the geosciences or geoscience degree programs (Levine et al., 2007; Houlton, 2010). This study both builds upon earlier studies and provides new insights about capacity building in the geosciences. Individuals who have been successfully pipelined into the geosciences ranging from upper-level undergraduates to decades-long professionals, were selected for an expert-novice study about field mapping. All of the 38 participants have field-mapping experience and were selected to achieve a balance of age, gender and experience in the sample and secondarily based on geographic diversity. Participants were asked how they became interested in geology as the last question of an interview about the other tasks during the study. Participants were surficially probed, in contrast to in-depth interviews conducted using critical incident methods. Remarkably, though the interview question was unstructured and open ended, the three persistent themes that emerged are consistent with previous studies of women geologists (Holmes and O'Connell, 2003), under-represented minorities (Levine et al., 2007), and undergraduate geoscience majors (Houlton, 2010): Role or influence of academic experience, influence of and/or connections with people and connections with Earth. Additionally, individual participant comments are well aligned the proposed framework by Kraft et al. (2011) for engaging geoscience students through the affective domain. We suggest that future studies should examine whether these findings are consistent across geologists from sub-domains that are less field-based and involve primarily modeling, or other computer- and lab

  15. Solution High-Energy Burst Assembly (SHEBA) results from subprompt critical experiments with uranyl fluoride fuel

    SciTech Connect

    Cappiello, C.C.; Butterfield, K.B.; Sanchez, R.G.

    1997-10-01

    The Solution High-Energy Burst Assembly (SHEBA) was originally constructed during 1980 and was designed to be a clean free-field geometry, right-circular, cylindrically symmetric critical assembly employing U(5%)O{sub 2}F{sub 2} solution as fuel. A second version of SHEBA, employing the same fuel but equipped with a fuel pump and shielding pit, was commissioned in 1993. This report includes data and operating experience for the 1993 SHEBA only. Solution-fueled benchmark work focused on the development of experimental measurements of the characterization of SHEBA; a summary of the results are given. A description of the system and the experimental results are given in some detail in the report. Experiments were designed to: (1) study the behavior of nuclear excursions in a low-enrichment solution, (2) evaluate accidental criticality alarm detectors for fuel-processing facilities, (3) provide radiation spectra and dose measurements to benchmark radiation transport calculations on a low-enrichment solution system similar to centrifuge enrichment plants, and (4) provide radiation fields to calibrate personnel dosimetry. 15 refs., 37 figs., 10 tabs.

  16. Dry critical experiments and analyses performed in support of the TOPAZ-2 safety program

    SciTech Connect

    Pelowitz, D.B.; Sapir, J.; Glushkov, E.S.; Ponomarev-Stepnoi, N.N.; Bubelev, V.G.; Kompanietz, G.B.; Krutov, A.M.; Polyakov, D.N.; Lobynstev, V.A.

    1995-01-20

    In December 1991, the Strategic Defense Initiative Organization decided to investigate the possibility of launching a Russian Topaz-2 space nuclear power system. Functional safety requirements developed for the Topaz mission mandated that the reactor remain subcritical when flooded and immersed in water. Initial experiments and analyses performed in Russia and the United States indicated that the reactor could potentially become supercritical in several water- or sand-immersion scenarios. Consequently, a series of critical experiments was performed on the Narciss M-II facility at the Kurchatov Institute to measure the reactivity effects of water and sand immersion, to quantify the effectiveness of reactor modifications proposed to preclude criticality, and to benchmark the calculational methods and nuclear data used in the Topaz-2 safety analyses. In this paper we describe the Narciss M-II experimental configurations along with the associated calculational models and methods. We also present and compare the measured and calculated results for the dry experimental configurations. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}

  17. Critical periods after stroke study: translating animal stroke recovery experiments into a clinical trial

    PubMed Central

    Dromerick, Alexander W.; Edwardson, Matthew A.; Edwards, Dorothy F.; Giannetti, Margot L.; Barth, Jessica; Brady, Kathaleen P.; Chan, Evan; Tan, Ming T.; Tamboli, Irfan; Chia, Ruth; Orquiza, Michael; Padilla, Robert M.; Cheema, Amrita K.; Mapstone, Mark E.; Fiandaca, Massimo S.; Federoff, Howard J.; Newport, Elissa L.

    2015-01-01

    Introduction: Seven hundred ninety-five thousand Americans will have a stroke this year, and half will have a chronic hemiparesis. Substantial animal literature suggests that the mammalian brain has much potential to recover from acute injury using mechanisms of neuroplasticity, and that these mechanisms can be accessed using training paradigms and neurotransmitter manipulation. However, most of these findings have not been tested or confirmed in the rehabilitation setting, in large part because of the challenges in translating a conceptually straightforward laboratory experiment into a meaningful and rigorous clinical trial in humans. Through presentation of methods for a Phase II trial, we discuss these issues and describe our approach. Methods: In rodents there is compelling evidence for timing effects in rehabilitation; motor training delivered at certain times after stroke may be more effective than the same training delivered earlier or later, suggesting that there is a critical or sensitive period for strongest rehabilitation training effects. If analogous critical/sensitive periods can be identified after human stroke, then existing clinical resources can be better utilized to promote recovery. The Critical Periods after Stroke Study (CPASS) is a phase II randomized, controlled trial designed to explore whether such a sensitive period exists. We will randomize 64 persons to receive an additional 20 h of upper extremity therapy either immediately upon rehab admission, 2–3 months after stroke onset, 6 months after onset, or to an observation-only control group. The primary outcome measure will be the Action Research Arm Test (ARAT) at 1 year. Blood will be drawn at up to 3 time points for later biomarker studies. Conclusion: CPASS is an example of the translation of rodent motor recovery experiments into the clinical setting; data obtained from this single site randomized controlled trial will be used to finalize the design of a Phase III trial. PMID

  18. Los Alamos Using Neutrons to Stop Nuclear Smugglers

    ScienceCinema

    Favalli, Andrea; Swinhoe, Martyn

    2014-06-02

    Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

  19. Los Alamos Using Neutrons to Stop Nuclear Smugglers

    SciTech Connect

    Favalli, Andrea; Swinhoe, Martyn

    2013-06-03

    Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

  20. Information about Practicums at Los Alamos

    SciTech Connect

    Bradley, Paul A.

    2012-07-24

    The Los Alamos Neutron Science Center is the premier facility for neutron science experiments ranging from cross section measurements, neutron scattering experiments, proton radiography, cold neutrons, actinide neutronic properties, and many other exciting topics. The National High Magnetic Field Laboratory is home to several powerful magnets, including the one that created the first non-destructive 100 Tesla field in March 2012. They probe the electronic structure of superconductors, magnetic properties of materials (including magneto-quantum effects). Research is also conducted in correlated materials, thermoacoustics, and magnetic properties of actinides. The Trident Laser has a unique niche with very high power, short pulse experiments, with a peak power of 10{sup 20} W in short pulse mode. Discoveries range from production of monoenergetic MeV ion beam, nonlinear kinetic plasma waves, the transition between kinetic and fluid nonlinear behavior and other laser-plasma interaction processes.

  1. Working with Fermi at Chicago and Los Alamos

    NASA Astrophysics Data System (ADS)

    Garwin, Richard L.

    2010-02-01

    I discuss my experience with Enrico Fermi as student and fellow faculty member at Chicago and with him as consultants to the Los Alamos Scientific Laboratory in 1950-1952. The talk shares observations about this great physicist and exemplary human being. )

  2. Optical velocimetry at the Los Alamos Proton Radiography Facility

    NASA Astrophysics Data System (ADS)

    Tupa, Dale; Tainter, Amy; Neukirch, Levi; Hollander, Brian; Buttler, William; Holtkamp, David; The Los Alamos Proton Radiography Team Team

    2016-05-01

    The Los Alamos Proton Radiography Facility (pRad) employs a high-energy proton beam to image the properties and behavior of materials driven by high explosives. We will discuss features of pRad and describe some recent experiments, highlighting optical diagnostics for surface velocity measurements.

  3. A progress report on UNICOS misuse detection at Los Alamos

    SciTech Connect

    Thompson, J.L.; Jackson, K.A.; Stallings, C.A.; Simmonds, D.D.; Siciliano, C.L.B.; Pedicini, G.A.

    1995-10-01

    An effective method for detecting computer misuse is the automatic monitoring and analysis of on-line user activity. During the past year, Los Alamos enhanced its Network Anomaly Detection and Intrusion Reporter (NADIR) to include analysis of user activity on Los Alamos` UNICOS Crays. In near real-time, NADIR compares user activity to historical profiles and tests activity against expert rules. The expert rules express Los Alamos` security policy and define improper or suspicious behavior. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes the implementation to date of the UNICOS component of NADIR, along with the operational experiences and future plans for the system.

  4. Student research in criticality safety at the University of Arizona

    SciTech Connect

    Hetrick, D.L.

    1997-06-01

    A very brief progress report on four University of Arizona student projects is given. Improvements were made in simulations of power pulses in aqueous solutions, including the TWODANT model. TWODANT calculations were performed to investigate the effect of assembly shape on the expansion coefficient of reactivity for solutions. Preliminary calculations were made of critical heights for the Los Alamos SHEBA assembly. Calculations to support French experiments to measure temperature coefficients of dilute plutonium solutions confirmed feasibility.

  5. RFQ development at Los Alamos

    SciTech Connect

    Wangler, T.P.; Crandall, K.R.; Stokes, R.H.

    1982-01-01

    The basic principles of the radio-frequency quadrupole (RFQ) linac are reviewed and a summary of past and present Los Alamos work is presented. Some beam-dynamics effects, important for RFQ design, are discussed. A design example is shown for xenon and a brief discussion of low-frequency RFQ structures is given.

  6. Experiences of fathering a baby admitted to neonatal intensive care: a critical gender analysis.

    PubMed

    Deeney, Kathleen; Lohan, Maria; Spence, Dale; Parkes, Jackie

    2012-09-01

    More fathers than ever before attend at the birth of their child and, internationally, there is a palpable pressure on maternity and neonatal services to include and engage with fathers. It is, thus, more important than ever to understand how fathers experience reproductive and neonatal health services and to understand how fathers can be successfully accommodated in these environments alongside their partners. In this paper we advance a theoretical framework for re-thinking fatherhood and health services approaches to fatherhood based on Critical Studies on Men (CSM). We illustrate the importance of this feminist informed theoretical approach to understanding the gendered experiences of fathers in a Neonatal Intensive Care Unit (NICU) setting in Northern Ireland. Using a longitudinal follow-up research design, with two data collection points, a total of 39 in-depth semi-structured interviews was conducted with 21 fathers of infants admitted to the NICU between August 2008 and December 2009. The findings demonstrate: (i) how men are forging new gendered identities around the birth of their baby but, over time, acknowledge women as the primary caregivers; (ii) how social class is a key determinant of men's ability to enact hegemonic forms of 'involved fatherhood' in the NICU, and; (iii) how men also encounter resistance from their partners and health professionals in challenging a gender order which associates women with the competent care of infants. An understanding of these gendered experiences operating at both individual and structural levels is critical to leading change for the inclusion of fathers as equal parents in healthcare settings. PMID:22694990

  7. The GUINEVERE experiment: First PNS measurements in a lead moderated sub-critical fast core

    SciTech Connect

    Thyebault, H. E.; Billebaud, A.; Chabod, S.; Lecolley, F. R.; Lecouey, J. L.; Lehaut, G.; Marie, N.; Ban, G.

    2012-07-01

    The GUINEVERE (Generation of Uninterrupted Intense Neutrons at the lead Venus Reactor) experimental program is dedicated to the study of Accelerator Driven System reactivity monitoring. It was partly carried out within the EUROTRANS integrated project (EURATOM FP6). GUINEVERE consists in coupling the fast core of the VENUS-F reactor (SCK-CEN, Mol (Belgium)), composed of enriched uranium and solid lead, with a T(d,n) neutron source provided by the GENEPI-3C deuteron accelerator. This neutron source can be operated in several modes: pulsed mode, continuous mode and also continuous mode with short beam interruptions (the so called 'beam trips'). In the past, the key questions of the reactivity control and monitoring in a subcritical system were studied in the MUSE experiments (1998-2004). These experiments highlighted the difficulty to determine precisely the reactivity with a single technique. This led to investigate a new strategy which is based on the combination of the relative reactivity monitoring via the core power to beam current relationship with absolute reactivity cross-checks during programmed beam interruptions. Consequently, to determine the reactivity, several dynamical techniques of reactivity determination have to be compared. In addition, their accuracy for absolute reactivity determination must be evaluated using a reference reactivity determination technique (from a critical state: rod drop and MSM measurements). The first sub-critical configuration which was studied was around k{sub eff} = 0.96 (SCI). Pulsed Neutron Source experiments (PNS) were carried out. The neutron population decrease was measured using fission chambers in different locations inside the core and the reflector. Neutron population time decrease was analyzed using fitting techniques and the Area Method Results obtained for the SCI reactivity will be shown, discussed and compared to the reference value given by the MSM method. (authors)

  8. Pre-Service Teachers' Critical Reflections of Arts and Education Discourse: Reconstructions of Experiences in Early Childhood and Higher Education

    ERIC Educational Resources Information Center

    Miller, Melinda G.; Nicholas, Ellen L.; Lambeth, Meaghan L.

    2008-01-01

    This layered account of arts education is produced through the three authors' critical reflections of experiences in their own early childhood education, and their pre-service teacher education. The first layer establishes links between the arts, learning in the arts and critically reflective practices through an account of teaching and learning…

  9. The undergraduate premedical experience in the United States: a critical review

    PubMed Central

    Lin, Katherine Y.; Parnami, Sonali; Fuhrel-Forbis, Andrea; Anspach, Renee R.; Crawford, Brett; De Vries, Raymond G.

    2013-01-01

    Objectives To better understand the consequences of the premedical years for the character of (future) physicians by critically reviewing the empirical research done on the undergraduate premedical experience in the United States. Methods We searched ERIC, JSTOR, PubMed, Scopus, ISI Web of Science, and PsycINFO from the earliest available date for empirical, peer-reviewed studies of premedical students in the United States. We then used qualitative methods to uncover overall themes present in this literature. Results The initial literature search identified 1,168 articles, 19 of which were included for review. Reviewed articles were published between 1976 and 2010 with the majority published prior to 1990. Articles covered two broad topics: explaining attrition from the premedical track, and investigating the personality traits and stereotypes of premedical students. Self-selection bias and high attrition rates were among the limitations of the reviewed articles. Conclusions There is very little current research on the premedical experience. Given the importance of the premedical years on the process of becoming a medical professional, it is imperative that we do more and better research on how the premedical experience shapes future physicians. PMID:23951400

  10. Star of Lima - Overview and optical diagnostics of a barium Alfven critical velocity experiment

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T.; Foeppl, H.; Valenzuela, A.

    1986-01-01

    The Alfven critical velocity mechanism for ionization of a neutral gas streaming across the magnetic field has been demonstrated in laboratory experiments. In March 1983, two rocket-borne experiments with Ba and Sr tested the effect in the wall-less laboratory of space from Punto Lobos, Peru, near 430 km altitude. 'Star of Lima' used a conical Ba shaped charge aimed at an instrument payload about 2 km away. Because of rocket overperformance the detonation occurred in partial sunlight, so that less than 21.6 percent of the ionizing UV was present. Particle and field measurements indicate the production of hot electrons and waves in the energy and frequency range that are respectively predicted to produce a cascade of ionization by the Alfven mechanism. However, the ionization fluxes and wave energy density did not reach cascade levels, and optical observations indicate that only 2.5 to 5 x 10 to the 20th Ba ions were produced. A substantial portion and perhaps all of the ionization could have been produced by solar UV. The failure of the Alfven process in this experiment is not well understood.

  11. New directions for critical internet health studies: representing cancer experience on the web.

    PubMed

    Seale, Clive

    2005-05-01

    Studies of health representations on the internet have been preoccupied with the assessment of their (medically-defined) accuracy and quality. This contrasts with studies of health representations in 'old' media, where critical sociological analyses are common. Medical sociologists have been concerned to establish the potential of web information in transforming professional-client relations. A case study of breast and prostate cancer web sites provides evidence of the increasing convergence of the 'new' medium of the internet and old media such as newspapers and television. Large institutions are now consolidating their presence on the web so that users experience increasingly similar messages across media platforms. Search engines and links to the web from old media sources direct people to heavily resourced, mainstream health sites where, in the case of cancer, representations of gender are strikingly similar to those found in studies of old media sources. The media convergence thesis contrasts with earlier celebrations of the internet as a new medium that would promote a diversity of perspectives on health. Using existing methods for analysing media texts and developing new methods where appropriate, sociologists and media analysts interested in health need to develop more critical perspectives on this important new medium. PMID:15998349

  12. Optical observations on the CRIT-II Critical Ionization Velocity Experiment

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Haerendel, G.; Valenzuela, A.

    1990-01-01

    A rocket borne Critical Ionization Velocity (CIV0 experiment was carried out from Wallops Island at dusk on May 4, 1989. Two barium shaped charges were released below the solar terminator (to prevent photoionization) at altitudes near 400 km. The ambient ionospheric electron density was 50,000/cu cm. The neutral barium jet was directed upward and at an angle of nominally 45 degrees to B which gives approximately 3 x 10 to the 23rd neutrals with super critical velocity. Ions created by a CIV process in the region of the neutral jet would travel up along B into sunlight where they can be detected optically. Well defined ion clouds (max. brightness 750 R) were observed in both releases. An ionization rate of 0.8 percent/sec (125 sec ionization time constant) can account for the observed ion cloud near the release field line, but the ionization rate falls off with increasing distance from the release. It is concluded that a CIV process was present in the neutral jet out to about 50 km from the release, which is significantly further than allowed by current theories.

  13. On the BepiColombo and juno radio science experiments: Precise models and critical estimates

    NASA Astrophysics Data System (ADS)

    Tommei, Giacomo

    2015-08-01

    Radio Science Experiments (RSEs) use radio links between spacecraft and Earth to look for changes in the frequency as well as roundtrip light time of signals to investigate geophysical phenomena and for tests of fundamental physics. BepiColombo and Juno are two space missions that will perform RSEs, thanks to a very accurate tracking: to extract the desired information, it is not sufficient to improve the precision of observations, we need also to develop accurate mathematical models making smaller the residuals, defined as the observed observables minus the computed observables. However, sometimes, even highly accurate mathematical models are not sufficient for the determination of a given parameter with the required accuracy. In this paper, after a brief summary of the mathematical models needed for top accuracy RSEs, we will present two critical cases from the simulations of the BepiColombo and Juno where also these accurate models may not be sufficient to determine some quantities with the desired accuracy

  14. Analyzing the thermionic reactor critical experiments. [thermal spectrum of uranium 235 core

    NASA Technical Reports Server (NTRS)

    Niederauer, G. F.

    1973-01-01

    The Thermionic Reactor Critical Experiments (TRCE) consisted of fast spectrum highly enriched U-235 cores reflected by different thicknesses of beryllium or beryllium oxide with a transition zone of stainless steel between the core and reflector. The mixed fast-thermal spectrum at the core reflector interface region poses a difficult neutron transport calculation. Calculations of TRCE using ENDF/B fast spectrum data and GATHER library thermal spectrum data agreed within about 1 percent for the multiplication factor and within 6 to 8 percent for the power peaks. Use of GAM library fast spectrum data yielded larger deviations. The results were obtained from DOT R Theta calculations with leakage cross sections, by region and by group, extracted from DOT RZ calculations. Delineation of the power peaks required extraordinarily fine mesh size at the core reflector interface.

  15. Analysis of selected critical experiments using ENDF/B-IV and ENDF/B-V data

    NASA Astrophysics Data System (ADS)

    Singh, U. N.; Rec, J. R.; Jonsson, A.

    1981-10-01

    Selected critical experiments - TRX 1 & 2 (U metal; BNL 1, 2, 3 (ThO2/U-233); and B & W TUPE 15B (ThO2/U-235) - were analyzed using ENDF/B-V data, and the results were compared to the measured parameters and to values obtained using ENDF/B-IV. Calculations were performed with DIT, an integral transport assembly design code. A heterogeneous cell calculation in 85 energy groups was performed for each configuration. Leakage was accounted for through B-1 calculation using the measured bucklings. Overall, ENDF/B-V data have been found to improve the agreement with experimental results with the exception of the TUPE 15B core. However, the changes in the capture cross sections of U-238 (epithermal) and Th-232 do not fully resolve the long-standing differences with the measurements.

  16. Water/sand flooded and immersed critical experiment and analysis performed in support of the TOPAZ-II Safety Program

    SciTech Connect

    Glushkov, E.S.; Ponomarev-Stepnoi, N.N.; Bubelev, V.G.; Garin, V.P.; Gomin, E.A.; Kompanietz, G.V.; Krutoy, A.M.; Lobynstev, V.A.; Maiorov, L.V.; Polyakov, D.N.

    1994-11-01

    Presented is a brief description of the Narciss-M2 critical assemblies, which simulate accidental water/wet-sand immersion of the TOPAZ-II reactor as well as water-flooding of core cavities. Experimental results obtained from these critical assemblies, including experiments with several fuel elements removed from the core, are shown. These configurations with several extracted fuel elements simulate a proposed fuel-out anticriticality-device modification to the TOPAZ-II reactor. Preliminary computational analysis of these experiments using the Monte Carlo neutron-transport method is outlined. Nuclear criticality safety of the TOPAZ-II reactor with an incorporated anticriticality unit is demonstrated.

  17. Critical Race Media Projects: Counterstories and Praxis (Re)Claim Chicana/o Experiences

    ERIC Educational Resources Information Center

    Alemán, Sonya M.; Alemán, Enrique, Jr.

    2016-01-01

    This article maps out two critical race media projects -- a documentary and a Chicana/o-centric student newspaper--developed by Chicana/o scholars seeking to fulfilll the promise of praxis hailed by critical race theorists. Fortified and guided by the quintessential tenets of critical race theory and Latino critical race theory, these critical…

  18. Creating an Alternate Reality: Critical, Creative, and Empathic Thinking Generated in the "Global Village Playground" Capstone Experience

    ERIC Educational Resources Information Center

    Dondlinger, Mary Jo; Wilson, Douglas A.

    2012-01-01

    The "Global Village Playground" ("GVP") was a capstone learning experience designed to address institutional assessment needs while providing an integrated and authentic learning experience for students aimed at fostering critical and creative thinking. In the "GVP", students work on simulated and real-world problems as a design team tasked with…

  19. Critical Experiments that Simulated Damp MOX Powders - Do They Meet the Need?

    SciTech Connect

    J. Blair Briggs; Dr. Ali Nouri; Dr. Claes Nordborg

    2005-09-01

    The OECD Nuclear Energy Agency (NEA) Working Party on Nuclear Criticality Safety (WPNCS) identified the MOX fuel manufacturing process as an area in which there is a need for additional integral benchmark data. The specific need focused on damp MOX powders. The WPNCS was ultimately asked by the NEA Nuclear Science Committee (NSC) to provide the framework for the selection and performance of new experiments that fill the identified need. A set of criteria was established to enable uniform comparison of experimental proposals with generic MOX application data. Criteria were established for five general characteristics: (1) neutronic parameters, (2) type of experiments, (3) financial aspects, (4) schedule, and (5) other considerations. Proposals were judged most importantly on their ability to match the neutronic parameters of predetermined MOX applications. The neutronic parameters that formed the basis for comparison included core average values (not local values) for flux, fission and capture rate; detailed balance data (fission and capture) for the main isotopes (Actinides, H and O); sensitivity coefficients to important nuclear reactions (fission, capture, elastic and inelastic scatter, nu-bar, mu-bar) for all uranium and plutonium isotopes, hydrogen, and oxygen; sensitivity profiles to the main nuclear reactions for uranium and plutonium isotopes; energy of average lethargy causing fission; and the average fission group energy. The focus of this paper is on the definition of the need; the neutronics criteria established to assess which, if any, of three proposed MOX experimental programs best meet the need; and the actual assessment of the proposed experimental programs.

  20. Sedimentation equilibria in polydisperse ferrofluids: critical comparisons between experiment, theory, and computer simulation.

    PubMed

    Elfimova, Ekaterina A; Ivanov, Alexey O; Lakhtina, Ekaterina V; Pshenichnikov, Alexander F; Camp, Philip J

    2016-05-14

    The sedimentation equilibrium of dipolar particles in a ferrofluid is studied using experiment, theory, and computer simulation. A theory of the particle-concentration profile in a dipolar hard-sphere fluid is developed, based on the local-density approximation and accurate expressions from a recently introduced logarithmic free energy approach. The theory is tested critically against Monte Carlo simulation results for monodisperse and bidisperse dipolar hard-sphere fluids in homogeneous gravitational fields. In the monodisperse case, the theory is very accurate over broad ranges of gravitational field strength, volume fraction, and dipolar coupling constant. In the bidisperse case, with realistic dipolar coupling constants and compositions, the theory is excellent at low volume fraction, but is slightly inaccurate at high volume fraction in that it does not capture a maximum in the small-particle concentration profile seen in simulations. Possible reasons for this are put forward. Experimental measurements of the magnetic-susceptibility profile in a real ferrofluid are then analysed using the theory. The concentration profile is linked to the susceptibility profile using the second-order modified mean-field theory. It is shown that the experimental results are not consistent with the sample being monodisperse. By introducing polydispersity in the simplest possible way, namely by assuming the system is a binary mixture, almost perfect agreement between theory and experiment is achieved. PMID:27042815

  1. Critical Ethnographic Analysis of "Doing Good" on Short-Term International Immersion Experiences.

    PubMed

    Elliot, Michelle L

    2015-09-01

    Reciprocal partnerships are growing alongside the rise of international learning and "doing" experiences for students and clinicians. This paper questions how global citizenship, the acquisition of awareness and skills to sensitively navigate through a rapidly globalized social world, is cultivated amidst international partnerships focused on short-term immersion opportunities. Using an ethnographic methodology to examine the experiences of occupational therapy students abroad, this paper addresses the potential for competing agendas when the motivation to participate within these partnerships is driven in part by a desire to "do good." The empirical lens was directed towards the students' verbal, written and enacted narratives rather than the sociocultural realm of the sending institution, the host organization or the occupational realities of the local communities, therefore is limited in discursive scope. Nevertheless, the need is great for further critical appraisal of objectives and expectations by all parties to foster a partnership culture of reciprocity and equality and to diminish the neocolonial legacy of Western expertise dissemination. By examining how the stated and implied desire to do good exists alongside the risk to do harm to individuals and international networks, the conclusions can be extended locally to highlight the challenges to "partnering up" between clinicians and patients. PMID:25925873

  2. On the evaluation of pebble bed reactor critical experiments using the PEBBED code

    SciTech Connect

    Hans D. Gougar; R. Sonat Sen

    2001-10-01

    The PEBBED pebble bed reactor fuel management code under development at the Idaho National Laboratory is designed for rapid design and analysis of pebble bed high temperature reactors (PBRs). Embedded within the code are the THERMIX-KONVEK thermal fluid solver and the COMBINE-7 spectrum generation code for inline cross section homogenization. Because 1D symmetry can be found at each stage of core heterogeneity; spherical at TRISO and pebble levels, and cylindrical at the control rod and core levels, the 1-D transport capability of ANISN is assumed to be sufficient in most cases for generating flux solutions for cross section homogenization. Furthermore, it is fast enough to be executed during the analysis or the equilibrium core. Multi-group diffusion-based design codes such as PEBBED and VSOP are not expected to yield the accuracy and resolution of continuous energy Monte Carlo codes for evaluation of critical experiments. Nonetheless, if the preparation of multigroup cross sections can adequately capture the physics of the mixing of PBR fuel elements and leakage from the core, reasonable results may be obtained. In this paper, results of the application of PEBBED to two critical experiments (HTR Proteus and HTR-10) and associated computational models are presented. The embedded 1-D transport solver is shown to capture the double heterogeneity of the pebble fuel in unit cell calculations. Eigenvalue calculations of a whole core are more challenging, particularly if the boron concentration is uncertain. The sensitivity of major safety parameters to variations in modeling assumptions, however, is shown to be minimal. The embedded transport solver can also be used to obtain control rod worths but only with adjustment of the local spectrum. Results are compared to those of other codes as well as Core 4 of the HTR-Proteus experiment which contains partially inserted rods. They indicate the need for a reference solution to adjust the radius of the graphite in the

  3. RFQ development at Los Alamos

    SciTech Connect

    Armstrong, D.D.; Cornelius, W.D.; Purser, F.O.; Jameson, R.A.; Wangler, T.P.

    1984-01-01

    We report recent progress on the two radio-frequency quadrupole (RFQ) structures being developed at Los Alamos. First, we report on the second 425-MHz RFQ for H/sup -/ acceleration, which is being built in a research effort to understand and further develop the RFQ. Second, we discuss progress on the 80-MHz cw RFQ for deuterons, which is being built for the Fusion Materials Irradiation Test (FMIT) facility.

  4. Qualitative critical incident study of patients’ experiences leading to emergency hospital admission with advanced respiratory illness

    PubMed Central

    Karasouli, Eleni; Munday, Daniel; Bailey, Cara; Staniszewska, Sophie; Hewison, Alistair; Griffiths, Frances

    2016-01-01

    Objectives The high volume of emergency admissions to hospital is a challenge for health systems internationally. Patients with lung cancer and chronic obstructive pulmonary disease (COPD) are frequently admitted to hospital as emergency cases. While the frequency of emergency admission has been investigated, few studies report patient experiences, particularly in relation to the decision-making process prior to emergency admission. We sought to explore patient and carer experiences and those of their healthcare professionals in the period leading up to emergency admission to hospital. Setting 3 UK hospitals located in different urban and rural settings. Design Qualitative critical incident study. Participants 24 patients with advanced lung cancer and 15 with advanced COPD admitted to hospital as emergencies, 20 of their carers and 50 of the health professionals involved in the patients’ care. Results The analysis of patient, carer and professionals’ interviews revealed a detailed picture of the complex processes involved leading to emergency admission to hospital. 3 phases were apparent in this period: self-management of deteriorating symptoms, negotiated decision-making and letting go. These were dynamic processes, characterised by an often rapidly changing clinical condition, uncertainty and anxiety. Patients considered their options drawing on experience, current and earlier advice. Patients tried to avoid admission, reluctantly accepting it, albeit often with a sense of relief, as anxiety increased with worsening symptoms. Conclusions Patients with advanced respiratory illness, and their carers, try to avoid emergency admission, and use logical and complex decision-making before reluctantly accepting it. Clinicians and policy-makers need to understand this complex process when considering how to reduce emergency hospital admissions rather than focusing on identifying and labelling admissions as ‘inappropriate’. PMID:26916687

  5. A validation study of existing neutronics tools against ZPPR-21 and ZPPR-15 critical experiments.

    SciTech Connect

    Yang, W.S.; Kim, S.J.

    2007-09-30

    A study was performed to validate the existing tools for fast reactor neutronics analysis against previous critical experiments. The six benchmark problems for the ZPPR-21 critical experiments phases A through F specified in the Handbook of Evaluated Criticality Safety Benchmark Experiments were analyzed. Analysis was also performed for three loading configurations of the ZPPR-15 Phase A experiments. As-built core models were developed in XYZ geometries using the reactor loading records and drawer master information. Detailed Monte Carlo and deterministic transport calculations were performed, along with various modeling sensitivity analyses. The Monte Carlo simulations were carried out with the VIM code with continuous energy cross sections based on the ENDF/B-V.2 data. For deterministic calculations, region-dependent 230-group cross sections were generated using the ETOE-2/MC-2/SDX code system, again based on the ENDF/B-V.2 data. Plate heterogeneity effects were taken into account by SDX unit cell calculations. Core calculations were performed with the TWODANT discrete ordinate code for the ZPPR-21 benchmarks, and with the DIF3D nodal transport option for the ZPPR-15 experiments. For all six ZPPR-21 configurations where the Pu-239 concentration varies from 0 to 49 w/o and the U-235 concentration accordingly varies from 62 to 0 w/o, the core multiplication factor determined with a 230-group TWODANT calculation agreed with the VIM Monte Carlo solution within 0.20 %{Delta}k, and there was no indication of any systematic bias. The quality of principal cross sections generated with the MC-2 code was comparable to that of VIM cross sections. The overall reactivity effect due to the errors in the 230-group principal cross sections was estimated to be less than 0.05 %{Delta}k. The statistics of the differences between calculated values and specified benchmark experimental values showed similar bias (from -0.28 %{Delta}k to 0.33 %{Delta}k) for MC{sup 2}-2/TWODANT and VIM

  6. Occurrences at Los Alamos National Laboratory: What can they tell us?

    SciTech Connect

    Richard A. Reichelt; A. Jeffery Eichorst; Marc E. Clay; Rita J. Henins; Judith D. DeHaven; Richard J. Brake

    2000-03-01

    The authors analyzed the evolution of institutional and facility response to groups of abnormal incidents at Los Alamos National Laboratory (LANL). The analysis is divided into three stages: (1) the LANL response to severe accidents from 1994 to 1996, (2) the LANL response to facility-specific clusters of low-consequence incidents from 1997 to 1999, and (3) the ongoing development of and response to a Laboratory-wide trending and analysis program. The first stage is characterized by five severe accidents at LANL--a shooting fatality, a forklift accident, two electrical shock incidents, and an explosion in a nuclear facility. Each accident caused LANL and the Department of Energy (DOE) to launch in-depth investigations. A recurrent theme of the investigations was the failure of LANL and DOE to identify and act on precursor or low-consequence events that preceded the severe accidents. The second stage is characterized by LANL response to precursor or low-consequence incidents over a two-year period. In this stage, the Chemistry and Metallurgy Research Facility, the Los Alamos Critical Experiments Facility, and the Los Alamos Neutron Science Center responded to an increase in low-consequence events by standing down their facilities. During the restart process, each facility collectively analyzed the low-consequence events and developed systemic corrective actions. The third stage is characterized by the development of a Laboratory-wide trending and analysis program, which involves proactive division-level analysis of incidents and development of systemic actions. The authors conclude that, while the stages show an encouraging evolution, the facility standdowns and restarts are overly costly and that the institutional trending and analysis program is underutilized. The authors therefore recommend the implementation of an institutional, mentored program of trending and analysis that identifies clusters of related low-consequence events, analyzes those events, and

  7. Critical Media Literacy and Popular Film: Experiences of Teaching and Learning in a Graduate Class

    ERIC Educational Resources Information Center

    Stuckey, Heather; Kring, Kelly

    2007-01-01

    This chapter describes the use of popular film and semiotics for the development of critical media literacy in a graduate-level education course entitled "Pop Culture as Pedagogy: The Role of Entertainment Media in Teaching for Critical Consciousness and Critical Media Literacy." The course focused on analysis of different forms of pop culture,…

  8. [The use of nitric oxide during transport of newborns with critical respiratory insufficiency: own experience, preliminary report].

    PubMed

    Ziebiński, Marek; Walas, Wojciech

    2002-01-01

    This preliminary report presents author's experience with inhaled nitric oxide during transport of newborns with critical respiratory insufficiency. The theoretical basis, indications and contraindications as well as principles of administration during transport are described. The required equipment and some technical aspects are discussed. A short preview of performed transportations is given. Preliminary data show, that use of NO during transport is very helpful in children with critical respiratory insufficiency. PMID:12108077

  9. Nuclear accident dosimetry studies at Los Alamos National Laboratory

    SciTech Connect

    Casson, W.H.; Buhl, T.E.; Upp, D.L.

    1995-12-01

    Two critical assemblies have been characterized at the Los Alamos Critical Experiments Facility (LACEF) for use in testing nuclear accident dosimeters and related devices. These device, Godiva IV and SHEBA II, have very different characteristics in both operation and emitted neutron energy spectra. The Godiva assembly is a bare metal fast burst device with a hard spectrum. This spectrum can be modified by use of several shields including steel, concrete, and plexiglas. The modified spectra vary in both average neutron energy and in the specific distribution of the neutron energies in the intermediate energy range. This makes for a very favorable test arrangement as the response ratios between different activation foils used in accident dosimeters are significantly altered such as the ratio between gold, copper, and sulfur elements. The SHEBA device is a solution assembly which has both a slow ramp and decay period and a much softer spectrum. The uncertainly introduced in the response of fast decay foils such as indium can therefore be evaluated into the test results. The neutron energy spectrum for each configuration was measured during low power operations with a multisphere system. These measurements were extended to high dose pulsed operation by use of TLDs moderated TLDs, and special activation techniques. The assemblies were used in the testing of several accident dosimetry devices in studies modeled after the Nuclear Accident Dosimetry Studies that were conducted at Oak Ridge National Laboratory for about 25 years using the Health Physics Research Reactor. It is our intention to conduct these studies approximately annually for the evaluation of the nuclear accident dosimeter systems currently in use within the DOE, alternative systems used internationally, and new dosimeter designs being developed or considered for field application. Participation in selected studies will be open to all participants.

  10. Spacelab experiment definition study on phase transition and critical phenomena in fluids: Interim report on experimental justification

    NASA Technical Reports Server (NTRS)

    Moldover, M. R.; Hocken, M. R.; Gammon, R. W.; Sengers, J. V.

    1976-01-01

    Pure fluids and fluid mixtures near critical points are identified and are related to the progress of several disciplines. Consideration is given to thermodynamic properties, transport properties, and the complex nonlinear phenomena which occur when fluids undergo phase transitions in the critical region. The distinction is made between practical limits which may be extended by advances in technology and intrinsic ones which arise from the modification of fluid properties by the earth's gravitational field. The kinds of experiments near critical points which could best exploit the low gravity environment of an orbiting laboratory are identified. These include studies of the index of refraction, constant volume specific heat, and phase separation.

  11. Criticality experiments with mixed plutonium and uranium nitrate solution at a plutonium fraction of 0.4 in slab geometry

    SciTech Connect

    Pohl, B.A.; Keeton, S.C.

    1997-09-01

    R. C. Lloyd of PNL has completed and published a series of critical experiments with mixed plutonium- uranium nitrate solutions (Reference 1). This series of critical experiments was part of an extensive program jointly sponsored by the U. S. Department of Energy (DOE) and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan and was carried out in the mid-1980`s. The experiments evaluated here (published as Report PNL-6327) were performed with mixed plutonium- uranium nitrate solution in a variable thickness slab tank with two 106.7 cm square sides and a width that could be varied from 7.6 to 22.8 cm. The objective of these experiments was to obtain experimental data to permit the validation of computer codes for criticality calculations and of cross-section data to minimize the uncertainties inherent therein, so that facility safety, efficiency, and reliability could be enhanced. The concentrations of the solution were about 105, 293, and 435 g(Pu+U)/liter with a ratio of plutonium to total heavy metal (plutonium plus uranium) of about 0. 40 for all eight experiments. Four measurements were made with a water reflector, and four with no reflector. Following the publication of the initial PNL reports, considerable effort was devoted to an extensive reevaluation of this series of experiments by a collaboration of researchers from ORNL, PNL, and PNC (Reference 2). Their work resulted in a more accurate description of the ``as built`` hardware configuration and the materials specifications. For the evaluations in this report, the data published in Reference 2 by Smolen et al. is selected to supersede the original PNL report. Eight experiments have been evaluated and seven (063, 064, 071, 072, 074, 075, and 076) provide benchmark criticality data. Experiment 073 could not achieve criticality within vessel height limitations.

  12. Why Deuterium+Au was the critical control experiment at RHIC

    NASA Astrophysics Data System (ADS)

    Gyulassy, Miklos

    2003-10-01

    One of the striking discoveries at RHIC was the strong (factor of 4-5) suppression of high pT pions above 4 GeV/c in central Au+Au at 200 AGeV. In addition the data reveal an evolution from di-jet correlations in peripheral collisions to mono-jet production in central collisions. Two paradigms existed prior to the new D+Au data proporting to explain the same jet quenching pattern. One is based on the formation of an opaque Quark-Gluon Plasma [1]. The other is based on initial state gluon shadowing in the Color Glass Condensate model for the nuclear wavefunction [2]. I review both paradigms and how the D+Au reaction provides the critical control experiment to decide which is closer to reality under RHIC conditions. I conclude that if the preliminary d+Au data are confirmed, then a QGP was in fact formed in central Au+Au at RHIC. References: [1] M. Gyulassy, Ivan Vitev, Xin-Nian Wang, Ben-Wei Zhang nucl-th/0302077 and refs. therein. [2] Edmond Iancu, Raju Venugopalan hep-ph/0303204 and refs. therein.

  13. K/sub infinity/-meter concept verified via subcritical-critical TRIGA experiments

    SciTech Connect

    Ocampo Mansilla, H.

    1983-01-01

    This work presents a technique for building a device to measure the k/sub infinity/ of a spent nuclear fuel assembly discharged from the core of a nuclear power plant. The device, called a k/sub infinity/-meter, consists of a cross-shaped subcritical assembly, two artificial neutron sources, and two separate neutron counting systems. The central position of the subcritical assembly is used to measure k/sub infinity/ of the spent fuel assembly. The initial subcritical assembly is calibrated to determine its k/sub eff/ and verify the assigned k/sub infinity/ of a selected fuel assembly placed in the central position. Count rates are taken with the fuel assembly of known k/sub infinity/'s placed in the central position and then repeated with a fuel assembly of unknown k/sub infinity/ placed in the central position. The count rate ratio of the unknown fuel assembly to the known fuel assembly is used to determine the k/sub infinity/ of the unknown fuel assembly. The k/sub infinity/ of the unknown fuel assembly is represented as a polynomial function of the count rate ratios. The coefficients of the polynomial equation are determined using the neutronic codes LEOPARD and EXTERMINATOR-II. The analytical approach has been validated by performing several subcritical/critical experiments, using the Penn State Breazeale TRIGA Reactor (PSBR), and comparing the experimental results with the calculations.

  14. Critical Heat Flux Experiments on the Reactor Vessel Wall Using 2-D Slice Test Section

    SciTech Connect

    Jeong, Yong Hoon; Chang, Soon Heung; Baek, Won-Pil

    2005-11-15

    The critical heat flux (CHF) on the reactor vessel outer wall was measured using the two-dimensional slice test section. The radius and the channel area of the test section were 2.5 m and 10 cm x 15 cm, respectively. The flow channel area and the heater width were smaller than those of the ULPU experiments, but the radius was greater than that of the ULPU. The CHF data under the inlet subcooling of 2 to 25 deg. C and the mass flux 0 to 300 kg/m{sup 2}.s had been acquired. The measured CHF value was generally slightly lower than that of the ULPU. The difference possibly comes from the difference of the test section material and the thickness. However, the general trend of CHF according to the mass flux was similar with that of the ULPU. The experimental CHF data were compared with the predicted values by SULTAN correlation. The SULTAN correlation predicted well this study's data only for the mass flux higher than 200 kg/m{sup 2}.s, and for the exit quality lower than 0.05. The local condition-based correlation was developed, and it showed good prediction capability for broad quality (-0.01 to 0.5) and mass flux (<300 kg/m{sup 2}.s) conditions with a root-mean-square error of 2.4%. There were increases in the CHF with trisodium phosphate-added water.

  15. Experience report: Using formal methods for requirements analysis of critical spacecraft software

    NASA Technical Reports Server (NTRS)

    Lutz, Robyn R.; Ampo, Yoko

    1994-01-01

    Formal specification and analysis of requirements continues to gain support as a method for producing more reliable software. However, the introduction of formal methods to a large software project is difficult, due in part to the unfamiliarity of the specification languages and the lack of graphics. This paper reports results of an investigation into the effectiveness of formal methods as an aid to the requirements analysis of critical, system-level fault-protection software on a spacecraft currently under development. Our experience indicates that formal specification and analysis can enhance the accuracy of the requirements and add assurance prior to design development in this domain. The work described here is part of a larger, NASA-funded research project whose purpose is to use formal-methods techniques to improve the quality of software in space applications. The demonstration project described here is part of the effort to evaluate experimentally the effectiveness of supplementing traditional engineering approaches to requirements specification with the more rigorous specification and analysis available with formal methods.

  16. Recent developments in the Los Alamos radiation transport code system

    SciTech Connect

    Forster, R.A.; Parsons, K.

    1997-06-01

    A brief progress report on updates to the Los Alamos Radiation Transport Code System (LARTCS) for solving criticality and fixed-source problems is provided. LARTCS integrates the Diffusion Accelerated Neutral Transport (DANT) discrete ordinates codes with the Monte Carlo N-Particle (MCNP) code. The LARCTS code is being developed with a graphical user interface for problem setup and analysis. Progress in the DANT system for criticality applications include a two-dimensional module which can be linked to a mesh-generation code and a faster iteration scheme. Updates to MCNP Version 4A allow statistical checks of calculated Monte Carlo results.

  17. Critical Components of a Successful Undergraduate Research Experience in the Geosciences for Minority Students

    NASA Astrophysics Data System (ADS)

    Liou-Mark, J.; Blake, R.; Chukuigwe, C.

    2013-12-01

    For the past five years, the New York City College of Technology has administered a successful National Science Foundation (NSF) Research Experience for Undergraduates (REU) program. The program provides rich, substantive, academic and life-transformative STEM educational experiences for students who would otherwise not pursue STEM education altogether or would not pursue STEM education through to the graduate school level. The REU Scholars are provided with an opportunity to conduct intensive satellite and ground-based remote sensing research at the National Oceanic and Atmospheric Administration Cooperative Remote Sensing Science and Technology Center (NOAA-CREST). Candidates for the program are recruited from the City University of New York's twenty-three separate campuses. These students engage in a research experience that spans the summer and the fall and spring semesters. Eighty-four percent (84%) of the program participants are underrepresented minorities in STEM, and they are involved in a plethora of undergraduate research best practice activities that include: training courses in MATLAB programming, Geographic Information Systems, and Remote Sensing; workshops in Research Ethics, Scientific Writing, and Oral and Poster Research Presentations; national, regional, and local conference presentations; graduate school support; and geoscience exposure events at national laboratories, agencies, and research facilities. To enhance their success in the program, the REU Scholars are also provided with a comprehensive series of safety nets that include a multi-tiered mentoring design specifically to address critical issues faced by this diverse population. Since the inception of the REU program in 2008, a total of 61 undergraduate students have finished or are continuing with their research or are pursuing their STEM endeavors. All the REU Scholars conducted individual satellite and ground-based remote sensing research projects that ranged from the study of

  18. Trauma-exposed firefighters: relationships among posttraumatic growth, posttraumatic stress, resource availability, coping and critical incident stress debriefing experience.

    PubMed

    Sattler, David N; Boyd, Bill; Kirsch, Julie

    2014-12-01

    This project examines protective factors associated with resilience/posttraumatic growth and risk factors associated with posttraumatic stress among firefighters exposed to critical incidents. The participants were 286 (257 men and 29 women) volunteer and paid firefighters in Whatcom County, Washington. Participants completed an anonymous survey asking about demographics, critical incident exposure, posttraumatic stress symptoms, posttraumatic growth, resource availability, coping, occupational stress and critical incident stress debriefing experience. Most participants had significant critical incident exposure, and about half had attended critical incident stress debriefing sessions. Posttraumatic growth was associated with being female, critical incident exposure, critical incident stress debriefing attendance, posttraumatic stress symptoms (negative association), occupational support, occupation satisfaction, occupational effort, problem-focused coping, emotion-focused coping and personal characteristic resources. Posttraumatic stress symptoms were positively associated with years of firefighting, burnout, occupational effort and disengagement coping and negatively associated with critical incident stress debriefing attendance, posttraumatic growth, social support, internal locus of control, personal characteristic resources, energy resources and condition resources. The findings support conservation of resources stress theory and show that the maintenance and acquisition of resources can offset losses and facilitate resilience/posttraumatic growth. Implications of the findings for enhancing firefighter resources, facilitating resilience and minimizing occupational stressors are discussed. PMID:25476961

  19. Results of critical velocity experiments with barium, strontium, and calcium releases from CRRES satellite

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hampton, D. L.; Delamere, P. A.

    1994-01-01

    As part of the NASA Combined Release and Radiation Effects Satellite (CRRES) chemical release program in September 1990, two Ba and also one each Sr and Ca canisters of a boron-titanium thermite mixture, which vaporizes the element on ignition, were released near perigee after dusk in the South Pacific to study the critical velocity effect proposed by Alfven. The critical velocities of these three elements are 2.7, 3.5, and 5.4 km/s respectively, all well below the orbital velocity of 9.4 km/s. On September 10, 1990, a Sr and Ba pair (G-13, or critical ionization velocity (CIV) I) was released near Rarotonga at approximately 515 km altitude in a background electron density of 3.4 x 10(exp 6)/cu cm. On September 14, 1990, G-14 or CIV II released a Ca and Ba pair west of New Caledonia near 595 km at an electron density of 1.5 x 10(exp 6)/cu cm. Ions of all three elements were observed with low-light level imagers from two aircraft after they had transited up the magnetic field lines into the sunlight. Emissions from the spherically expanding neutral gas shells below the solar terminator, observed with cameras filtered for the Ba(+) ion line at 4554 A and also in unfiltered imagers for approximately 15 s after release, are probably due to excitation by hot electrons created in the CIV process. The ions created clearly lost much of their energy, which we now show can be explained by elastic collisions: Ba(+) + O. Inventories of the observed ions indicate yields of 0.15% and 1.84% for Ba in the first and second experiments, 0.02% for Sr and 0.27% for Ca. Ionization from all the releases continued along the satellite trajectory much longer (greater than 45 s) than expected for a CIV process. The ion production along the satellite track versus time typically shows a rapid rise to a peak in a few seconds followed by an exponential decrease to a level essentially constant rate. The characteristic distances for CIV I and II are 47 and 62 km, respectively. We interpret the

  20. Promotion of critical thinking in e-learning: a qualitative study on the experiences of instructors and students

    PubMed Central

    Gharib, Mitra; Zolfaghari, Mitra; Mojtahedzadeh, Rita; Mohammadi, Aeen; Gharib, Atoosa

    2016-01-01

    Background With the increasing popularity of e-learning programs, educational stakeholders are attempting to promote critical thinking in the virtual education system. This study aimed to explore the experiences of both the instructors and the students about critical thinking promotion within the virtual education system. Methods This qualitative study recruited the instructors and students from four academic disciplines provided by the Virtual School of Tehran University of Medical Sciences (Tehran, Iran). All programs were master’s degree programs and utilized a blended (combination of e-learning and face to face) training. Semistructured interviews with the participants were used to collect data. Results The participants had a variety of experiences about how to promote critical thinking. These experiences were conceptualized in four main themes, namely, instructional design, educational leadership and management, local evidence, and belief systems. Conclusion The present study clarified the factors affecting critical thinking promotion in e-learning. Not only the instructors but also the educational designers and leaders can benefit from our findings to improve the quality of virtual education programs and promote critical thinking. PMID:27217807

  1. Determining the tube bundle streamlining critical parameters using the numerical experiment method

    NASA Astrophysics Data System (ADS)

    Kaplunov, S. M.; Val'es, N. G.; Samolysov, A. V.; Marchevskaya, O. A.

    2015-08-01

    The article is devoted to development and application of mathematical models describing the most dangerous mechanisms through which vibrations are excited in tube bundles and blunt cylindrically shaped structures, and to development of reliable calculation methods for describing these models, which would make it possible to obtain prompt data for designing and subsequent operation of the considered structural elements. For solving such problems, a comprehensive approach is required, which should be based on a combined use of numerical experiments on computers and experimental investigations on full-scale equipment. The authors have developed a procedure for numerically investigating the hydrodynamic forces arising during stalled streamlining and the tube bundle vibrations caused by these forces. The procedure is based on using the developed mathematical model describing fluid-elastic excitation of vibrations in a bundle of elastic tubes placed in external cross flow. The problem of studying fluid-elastic excitation is brought to stability analysis, which is carried out with the assumption about a linear behavior of destabilizing forces for undisturbed state of elastic tubes. A theoretical investigation of the developed mathematical model was carried out, from which the necessary and sufficient condition of system stability has been obtained in terms of system dimensionless parameters (mass, damping, and velocity). An algorithm for numerically determining the matrices of linear hydrodynamic coupling coefficients for particular tube bundles is developed. The validity of the algorithm and the computer programs developed on its basis are checked by comparing the results of test calculations with the bank of known experimental data. A procedure is proposed for determining the matrices of linear hydrodynamic coupling coefficients in bundles having a regular layout of their cross section and a large number of tubes through calculating these matrices for a relatively small

  2. Campus Climate and the Underrepresented Minority Engineering Student Experience: A Critical Race Study

    NASA Astrophysics Data System (ADS)

    Mayes, Terrance

    In the current technological era, the number of minorities in science, technology, engineering, and mathematics (STEM) is a crucial factor in predetermining the economic growth of the United States. Since the minority population is growing at much faster rates than the non-minority population, the lack of proportionate production of minority engineers poses a threat to the United States' ability to remain a global competitor in technological innovation. Sixty-three per cent (63%) of undergraduate students who enter engineering majors continue on to graduate in that major. The graduation rate, however, for African-American, Hispanic, and Native-American students in engineering is significantly lower at 39%. As this group represents only a small fraction of the annual student enrollment, engineering programs are graduating these minority groups at rates that are greatly disproportionate to United States demographics. Therefore, researchers are thoroughly investigating certain initiatives that promote academic success among underrepresented minority students in engineering. Colleges and universities have attempted to address the growing achievement gap between underrepresented minority and non-minority engineering students, predominately through various deficit-based interventions, focusing on the student's flaws and problems. As the pipeline for minorities in engineering continues to narrow, it begs the question of whether institutions are focusing on the right solutions to the problem. Critical Race Theory scholars argue that colleges and universities must address institutional climate issues around students, such as racism, microaggressions, and marginalization, before members of oppressed groups can truly succeed. This dissertation explored the unique experiences of underrepresented minority engineering students in a predominately White and Asian campus.

  3. Power Distribution Analysis for the ORNL High Flux Isotope Reactor Critical Experiment 3

    SciTech Connect

    Chandler, David; Primm, Trent; Maldonado, G Ivan

    2010-01-01

    The mission of the Reduced Enrichment for Research and Test Reactors Program is to minimize and, to the extent possible, eliminate the use of highly enriched uranium (HEU) in civilian nuclear applications by working to convert research and test reactors, as well as radioisotope production processes, to low-enriched uranium (LEU) fuel and targets. Oak Ridge National Laboratory (ORNL) is currently reviewing the design bases and key operating criteria including fuel operating parameters, enrichment-related safety analyses, fuel performance, and fuel fabrication in regard to converting the fuel of the High Flux Isotope Reactor (HFIR) from HEU to LEU. The purpose of this study is to validate Monte Carlo methods currently in use for conversion analyses. The methods have been validated for the prediction offlux values in the reactor target, reflector, and beam tubes, but this study focuses on the prediction of the power density profile in the core. Power distributions were calculated in the fuel elements of the HFIR, a research reactor at ORNL, via MCNP and were compared to experimentally obtained data. This study was performed to validate Monte Carlo methods for power density calculations and to observe biases. A current three-dimensional MCNP model was modified to replicate the 1965 HFIR Critical Experiment 3 (HFIRCE-3). In this experiment, the power profile was determined by counting the gamma activity at selected locations in the core. 'Foils' (chunks of fuel meat and clad) were punched out of the fuel elements in HFIRCE-3 following irradiation, and experimental relative power densities were obtained by measuring the activity of these foils and comparing each foil's activity to the activity of a normalizing foil. This analysis consisted of calculating corresponding activities by inserting volume tallies into the modified MCNP model to represent the punchings. The average fission density was calculated for each foil location and then normalized to the reference foil

  4. Analysis results from the Los Alamos 2D/3D program

    SciTech Connect

    Boyack, B.E.; Cappiello, M.W.; Stumpf, H.; Shire, P.; Gilbert, J.; Hedstrom, J.

    1986-01-01

    Los Alamos National Laboratory is a participant in the 2D/3D program. Activities conducted at Los Alamos National Laboratory in support of 2D/3D program goals include analysis support of facility design, construction, and operation; provision of boundary and initial conditions for test facility operations based on analysis of pressurized water reactors; performance of pretest and posttest predictions and analyses; and use of experimental results to validate and assess the single- and multidimensional nonequilibrium features in the Transient Reactor Analysis Code (TRAC). During Fiscal Year 1986, Los Alamos conducted analytical assessment activities using data from the Cylindrical Core Test Facility and the Slab Core Test Facility. Los Alamos also continued to provide support analysis for the planning of Upper Plenum Test Facility experiments. Finally, Los Alamos either completed or is currently working on three areas of TRAC modeling improvement. In this paper, Los Alamos activities during Fiscal Year 1986 are summarized; several significant accomplishments are described in more detail to illustrate the work activities at Los Alamos.

  5. Enhancing Critical Thinking across the Undergraduate Experience: An Exemplar from Engineering

    ERIC Educational Resources Information Center

    Ralston, Patricia A.; Bays, Cathy L.

    2013-01-01

    Faculty in a large, urban school of engineering designed a longitudinal study to assess the critical thinking skills of undergraduate students as they progressed through the engineering program. The Paul-Elder critical thinking framework was used to design course assignments and develop a holistic assessment rubric. The curriculum was re-designed…

  6. Water/sand flooded and immersed critical experiment and analysis performed in support of the TOPAZ-II safety program

    SciTech Connect

    Glushkov, E.S.; Ponomarev-Stepnoi, N.N.; Bubelev, V.G.; Garin, V.P.; Gomin, E.A.; Kompanietz, G.V.; Krutov, A.M.; Lobynstev, V.A.; Maiorov, L.V.; Polyakov, D.N.; Chunyaev, E.I.; Marshall, A.C.; Sapir, J.L.; Pelowitz, D.B.

    1995-01-20

    Presented is a brief description of the Narciss-M2 critical assemblies, which simulate accidental water/wet-sand immersion of the TOPAZ-II reactor as well as water-flooding of core cavities. Experimental results obtained from these critical assemblies, including experiments with several fuel elements removed from the core, are shown. These configurations with several extracted fuel elements simulate a proposed fuel-out anticriticality-device modification to the TOPAZ-II reactor. Preliminary computational analysis of these experiments using the Monte Carlo neutron-transport method is outlined. Nuclear criticality safety of the TOPAZ-II reactor with an incorporated anticriticality unit is demonstrated. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}

  7. Teaching Computers to Tell Learning Stories: Using Critical Narrative Theory to Frame Design and Evaluation Strategies for Online Educational Experiences

    ERIC Educational Resources Information Center

    Voithofer, Rick

    2004-01-01

    Through a critical analysis of Classroom Connect's Quest experiences from 1998-2002, this study provides a framework for using narrative theory to guide the design and evaluation of educational multimedia and online education. Narrative theory, derived from literary and media studies and influenced by cultural studies, offers numerous parallels to…

  8. Can Educators Make a Difference? Experimenting with, and Experiencing, Democracy in Education. Critical Constructions: Studies on Education and Society

    ERIC Educational Resources Information Center

    Carr, Paul R., Ed.; Zyngier, David, Ed.; Pruyn, Marc, Ed.

    2012-01-01

    As the title of this book suggests, how one understands, perceives and experiences democracy may have a significant effect on how he/she actually engages in, and with, democracy. Within the educational context, this is a key concern, and forms the basis of the research presented in this volume within a critical, comparative analysis. The Global…

  9. Assessment of Zero Power Critical Experiments and Needs for a Fission Surface Power System

    SciTech Connect

    Jim R Parry; John Darrell bess; Brad T. Rearden; Gary A. Harms

    2009-06-01

    The National Aeronautics and Space Administration (NASA) is providing funding to the Department of Energy (DOE) to assess, develop, and test nuclear technologies that could provide surface power to a lunar outpost. Sufficient testing of this fission surface power (FSP) system will need to be completed to enable a decision by NASA for flight development. The near-term goal for the FSP work is to conduct the minimum amount of testing needed to validate the system performance within an acceptable risk. This report attempts to assess the current modeling capabilities and quantify any bias associated with the modeling methods for designing the nuclear reactor. The baseline FSP system is a sodium-potassium (NaK) cooled, fast spectrum reactor with 93% 235U enriched HEU-O2 fuel, SS316 cladding, and beryllium reflectors with B4C control drums. The FSP is to produce approximately 40 kWe net power with a lifetime of at least 8 years at full power. A flight-ready FSP is to be ready for launch and deployment by 2020. Existing benchmarks from the International Criticality Safety Benchmark Evaluation Program (ICSBEP) were reviewed and modeled in MCNP. An average bias of less than 0.6% was determined using the ENDF/B-VII cross-section libraries except in the case of subcritical experiments, which exhibited an average bias of approximately 1.5%. The bias increases with increasing reflector worth of the beryllium. The uncertainties and sensitivities in cross section data for the FSP model and ZPPR-20 configurations were assessed using TSUNAMI-3D. The cross-section covariance uncertainty in the FSP model was calculated as 2.09%, which was dominated by the uncertainty in the 235U(n,?) reactions. Global integral indices were generated in TSUNAMI-IP using pre-release SCALE 6 cross-section covariance data. The ZPPR-20 benchmark models exhibit strong similarity with the FSP model. A penalty assessment was performed to determine the degree of which the FSP model could not be characterized

  10. Bias and Uncertainty of Critical Experiment Models with CSAS25 from SCALE4.4a for Criticality Safety Analyses On the HP J-5600 (CMODB) Workstation

    SciTech Connect

    Smith, R.H.; Keener, H.J.; DeClue, J.F.; Krass, A.W.; Cain, V.R.

    2001-02-01

    This report documents establishment of bias, bias trends and uncertainty for validation of the CSAS25 control module from the SCALE 4.4a computer code system for use in evaluating criticality safety of uranium systems. The 27-group ENDF/B-IV, 44-group ENDF/B-V, and 238-group ENDF/B-V cross-section libraries were used. The criticality validation calculations were performed using over 500 benchmark cases from Volumes II and IV of the ''International Handbook of Evaluated Criticality Safety Benchmark Experiments,'' published by the Nuclear Energy Agency Organization for Economic Cooperation and Development (NEA/OECD). Based on statistical analysis of the calculation results, the bias, bias trends and uncertainty of the benchmark calculations have been established for these benchmark experiments. Numerical methods for applying margins are briefly described, but the determination of appropriate correlating parameter and values for additional margin, applicable to a particular analysis, must be determined as part of process analysis. As such, this document does not specify upper subcritical limits as has been done in the past. A follow-on report will be written to assess the methods for determination of an upper safety limit in more detail, provide comparisons, and recommend a preferred method. Analysts using these results are responsible for exercising sound engineering judgment using strong technical arguments to develop a margin in k{sub eff} or other correlating parameter that is sufficiently large to ensure that conditions (calculated by this method to be subcritical by this margin) will actually be subcritical. Documentation of determination and justification of the appropriate margin in the analyst's evaluation, in conjunction with this report, will constitute the complete Validation Report in accordance with ANSI/ANS-8.1-1998, Section 4.3.6(4).

  11. Use of Sensitivity and Uncertainty Analysis in the Design of Reactor Physics and Criticality Benchmark Experiments for Advanced Nuclear Fuel

    SciTech Connect

    Rearden, B.T.; Anderson, W.J.; Harms, G.A.

    2005-08-15

    Framatome ANP, Sandia National Laboratories (SNL), Oak Ridge National Laboratory (ORNL), and the University of Florida are cooperating on the U.S. Department of Energy Nuclear Energy Research Initiative (NERI) project 2001-0124 to design, assemble, execute, analyze, and document a series of critical experiments to validate reactor physics and criticality safety codes for the analysis of commercial power reactor fuels consisting of UO{sub 2} with {sup 235}U enrichments {>=}5 wt%. The experiments will be conducted at the SNL Pulsed Reactor Facility.Framatome ANP and SNL produced two series of conceptual experiment designs based on typical parameters, such as fuel-to-moderator ratios, that meet the programmatic requirements of this project within the given restraints on available materials and facilities. ORNL used the Tools for Sensitivity and Uncertainty Analysis Methodology Implementation (TSUNAMI) to assess, from a detailed physics-based perspective, the similarity of the experiment designs to the commercial systems they are intended to validate. Based on the results of the TSUNAMI analysis, one series of experiments was found to be preferable to the other and will provide significant new data for the validation of reactor physics and criticality safety codes.

  12. CRITICAL EXPERIMENTS TO DETERMINE IF EARLY NUTRITIONAL INFLUENCES ON EPIGENETIC MECHANISMS CAUSE METABOLIC IMPRINTING IN HUMANS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metabolic imprinting occurs when nutritional influences during critical periods of development cause specific metabolic adaptations that persist to adulthood. Epigenetic mechanisms, which regulate the broad diversity of tissue-specific gene expression, are established during development and largely ...

  13. Criticality experiments and analysis of molybdenum reflected cylindrical uranyl fluoride water solution reactors

    NASA Technical Reports Server (NTRS)

    Fieno, D.; Fox, T.; Mueller, R.

    1972-01-01

    Clean criticality data were obtained from molybdenum-reflected cylindrical uranyl-fluoride-water solution reactors. Using ENDF/B molybdenum cross sections, a nine energy group two-dimensional transport calculation of a reflected reactor configuration predicted criticality to within 7 cents of the experimental value. For these reactors, it was necessary to compute the reflector resonance integral by a detailed transport calculation at the core-reflector interface volume in the energy region of the two dominant resonances of natural molybdenum.

  14. Los Alamos Science, Number 25 -- 1997: Celebrating the Neutrino

    DOE R&D Accomplishments Database

    Cooper, N. G. ed.

    1997-01-01

    This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solar neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.

  15. Los Alamos Science, Number 25 -- 1997: Celebrating the neutrino

    SciTech Connect

    Cooper, N.G.

    1997-12-31

    This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solar neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.

  16. DOES CRITICAL MASS DECREASE AS TEMPERATURE INCREASES: A REVIEW OF FIVE BENCHMARK EXPERIMENTS THAT SPAN A RANGE OF ELEVATED TEMPERATURES AND CRITICAL CONFIGURATIONS

    SciTech Connect

    Yates, K.

    2009-06-10

    Five sets of benchmark experiments are reviewed herein that cover a diverse set of fissile system configurations. The review specifically focused on the change in critical mass of these systems at elevated temperatures and the temperature reactivity coefficient ({alpha}{sub T}) on the system. Because plutonium-based critical benchmark experiments at varying temperatures were not found at the time this review was prepared, only uranium-based systems are included, as follows: (1) HEU-SOL-THERM-010 - UO{sub 2}F{sub 2} solutions with high U{sup 235} enrichment; (2) HEU-COMP-THERM-016 - uranium-graphite blocks with low U concentration; (3) LEU-COMP-THERM-032 - water moderated lattices of UO{sub 2} with stainless steel cladding, and intermediate U{sup 235} enrichment; (4) IEU-COMP-THERM-002 - water moderated lattices of annular UO{sub 2} with/without absorbers, and intermediate U{sup 235} enrichment; and (5) LEU-COMP-THERM-026 - water moderated lattices of UO{sub 2} at different pitches, and low U{sup 235} enrichment. In three of the five benchmarks (1, 3 and 5), modeling of the critical system at room temperature is conservative compared to modeling the system at elevated temperatures, i.e., a greater fissile mass is required at elevated temperature. In one benchmark (4), there was no difference in the fissile mass between the room temperature system and the system at the examined elevated temperature. In benchmark (2), the system clearly had a negative temperature reactivity coefficient. Some of the high temperature benchmark experiments were treated with appropriate (and comprehensive) adjustments to the cross section sets and thermal expansion coefficients, while other experiments were treated with partial adjustments. Regardless of the temperature treatment, modeling the systems at room temperature was found to be conservative for the examined systems, i.e., a smaller critical mass was obtained. While the five benchmarks presented herein demonstrate that, for the

  17. Los Alamos PC estimating system

    SciTech Connect

    Stutz, R.A.; Lemon, G.D.

    1987-01-01

    The Los Alamos Cost Estimating System (QUEST) is being converted to run on IBM personal computers. This very extensive estimating system is capable of supporting cost estimators from many different and varied fields. QUEST does not dictate any fixed method for estimating. QUEST supports many styles and levels of detail estimating. QUEST can be used with or without data bases. This system allows the estimator to provide reports based on levels of detail defined by combining work breakdown structures. QUEST provides a set of tools for doing any type of estimate without forcing the estimator to use any given method. The level of detail in the estimate can be mixed based on the amount of information known about different parts of the project. The system can support many different data bases simultaneously. Estimators can modify any cost in any data base.

  18. Critical heat-flux experiments under low-flow conditions in a vertical annulus. [PWR; BWR; LMFBR

    SciTech Connect

    Mishima, K.; Ishii, M.

    1982-03-01

    An experimental study was performed on critical heat flux (CHF) at low flow conditions for low pressure steam-water upward flow in an annulus. The test section was transparent, therefore, visual observations of dryout as well as various instrumentations were made. The data indicated that a premature CHF occurred due to flow regime transition from churn-turbulent to annular flow. It is shown that the critical heat flux observed in the experiment is essentially similar to a flooding-limited burnout and the critical heat flux can be well reproduced by a nondimensional correlation derived from the previously obtained criterion for flow regime transition. The observed CHF values are much smaller than the standard high quality CHF criteria at low flow, corresponding to the annular flow film dryout. This result is very significant, because the coolability of a heater surface at low flow rates can be drastically reduced by the occurrence of this mode of CHF.

  19. The physics of sub-critical lattices in accelerator driven hybrid systems: The MUSE experiments in the MASURCA facility

    SciTech Connect

    Chauvin, J. P.; Lebrat, J. F.; Soule, R.; Martini, M.; Jacqmin, R.; Imel, G. R.; Salvatores, M.

    1999-06-10

    Since 1991, the CEA has studied the physics of hybrid systems, involving a sub-critical reactor coupled with an accelerator. These studies have provided information on the potential of hybrid systems to transmute actinides and, long lived fission products. The potential of such a system remains to be proven, specifically in terms of the physical understanding of the different phenomena involved and their modelling, as well as in terms of experimental validation of coupled systems, sub-critical environment/accelerator. This validation must be achieved through mock-up studies of the sub-critical environments coupled to a source of external neutrons. The MUSE-4 mock-up experiment is planed at the MASURCA facility and will use an accelerator coupled to a tritium target. The great step between the generator used in the past and the accelerator will allow to increase the knowledge in hybrid physic and to decrease the experimental biases and the measurement uncertainties.

  20. MCNP benchmark analyses of critical experiments for space nuclear thermal propulsion

    SciTech Connect

    Selcow, E.C.; Cerbone, R.J.; Ludewig, H. )

    1993-01-01

    The particle-bed reactor (PBR) system is being developed for use in the Space Nuclear Thermal Propulsion (SNTP) Program. This reactor system is characterized by a highly heterogeneous, compact configuration with many streaming pathways. The neutronics analyses performed for this system must be able to accurately predict reactor criticality, kinetics parameters, material worths at various temperatures, feedback coefficients, and detailed fission power and heating distributions. The latter includes coupled axial, radial, and azimuthal profiles. These responses constitute critical inputs and interfaces with the thermal-hydraulics design and safety analyses of the system.

  1. Tiger Team Assessment of the Los Alamos National Laboratory

    SciTech Connect

    Not Available

    1991-11-01

    The purpose of the safety and health assessment was to determine the effectiveness of representative safety and health programs at the Los Alamos National Laboratory (LANL). Within the safety and health programs at LANL, performance was assessed in the following technical areas: Organization and Administration, Quality Verification, Operations, Maintenance, Training and Certification, Auxiliary Systems, Emergency Preparedness, Technical Support, Packaging and Transportation, Nuclear Criticality Safety, Security/Safety Interface, Experimental Activities, Site/Facility Safety Review, Radiological Protection, Personnel Protection, Worker Safety and Health (OSHA) Compliance, Fire Protection, Aviation Safety, Explosives Safety, Natural Phenomena, and Medical Services.

  2. Women's experiences of symptoms of posttraumatic stress disorder (PTSD) after traumatic childbirth: a review and critical appraisal.

    PubMed

    James, Stella

    2015-12-01

    This paper critically analyses nine studies on postnatal posttraumatic stress disorder (PTSD) following traumatic childbirth, in order to find common themes of PTSD symptoms, using the cognitive model of PTSD as a guide; it critically appraised one of the studies in depth and it attempted to explain the lived experience of women suffering from postnatal PTSD following traumatic childbirth and the suitability of cognitive behavioural therapy (CBT) for postnatal PTSD. This paper found that women following traumatic childbirth do experience postnatal PTSD; postnatal PTSD symptoms are similar to PTSD symptoms of other events and that CBT for PTSD of other events is just as effective for postnatal PTSD. Future recommendations include more qualitative studies with interpretative phenomenological approach in order to establish evidence-based CBT treatment for this client group, and more referrals need to be sent to the psychological services for CBT intervention. PMID:26264506

  3. In Pursuit of Critical Literacy: Understanding Experiences of Exclusion for Adult Literacy Learners

    ERIC Educational Resources Information Center

    Howard, Margaret; Logan, Anna

    2012-01-01

    This paper explores exclusion and equality through critical theory, in the context of adult literacy provision in Ireland, by investigating the sites of exclusion that exist for a group of five male adult literacy learners. A summary review of literacy theories, exclusion and equality is provided framing the reporting of data from this…

  4. Voice, Identity, and the Organizing of Student Experience: Managing Pedagogical Dilemmas in Critical Classroom Discussions

    ERIC Educational Resources Information Center

    Yannuzzi, Thomas J.; Martin, Daniela

    2014-01-01

    The current paper explores the discursive complexities of teaching and learning in inclusive, critically oriented classrooms. It argues that to accomplish the ontological goals of higher learning, we need to focus on the construction of student voice, or the ability to be considered in and have influence on teaching and learning. The paper further…

  5. Reconceptualizing Self and Other through Critical Media Engagement. Experiences and Reflections of English Learners and Teacher

    ERIC Educational Resources Information Center

    Huang, Shin-ying

    2015-01-01

    This research explores how critical media literacy transforms ways of engaging with media texts and expands the understanding and practice of literacy. In this qualitative teacher inquiry, even though the teacher researcher had envisioned for the students an identity as academic-language learners who engage with competing ideologies of masculinity…

  6. Critical source area management of agricultural phosphorus: experiences, challenges and opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The concept of critical source areas of phosphorus (P) loss produced by coinciding source and transport factors has been studied since the mid 1990s. It is widely recognized that identification of such areas has led to targeting of management strategies and conservation practices that more effectiv...

  7. Critically Ill Patients and End-of-Life Decision-Making: The Senior Medical Resident Experience

    ERIC Educational Resources Information Center

    Ahern, Stephane P.; Doyle, Tina K.; Marquis, Francois; Lesk, Corey; Skrobik, Yoanna

    2012-01-01

    In order to improve the understanding of educational needs among residents caring for the critically ill, narrative accounts of 19 senior physician trainees participating in level of care decision-making were analyzed. In this multicentre qualitative study involving 9 university centers in Canada, in-depth interviews were conducted in either…

  8. New Graduate Nurses' Perceived Definition of Critical Thinking during Their First Nursing Experience

    ERIC Educational Resources Information Center

    Kaddoura, Mahmoud

    2013-01-01

    Critical thinking (CT) is a flourishing concept that has been developing throughout the fields of both nursing education and practice. In fact, every person thinks in his or her own way that is varied among individuals; it is the nature of human mankind to do so. Nevertheless, much of our thinking might be subjective, indefinite, limited,…

  9. Studying Critical Classroom Encounters: The Experiences of Students in German College Education

    ERIC Educational Resources Information Center

    Voss, Roediger

    2009-01-01

    Purpose: This paper seeks to explore satisfactory and unsatisfactory classroom (student-lecturer) encounters in higher education from a student's perspective. Design/methodology/approach: The critical incident technique (CIT) is used to categorise positive and negative student-lecturer interactions, to reveal quality dimensions of the lecturer,…

  10. Critical Race Theory and Social Studies: Centering the Native American Experience

    ERIC Educational Resources Information Center

    Chandler, Prentice T.

    2010-01-01

    This article looks at the ways in which the topic of race is treated in social studies classrooms and the conceptual application of the field of critical race theory (CRT) to the teaching of American history. The author discusses the field of the social studies in terms of its stated goals and how these goals are not met because of a lack of…

  11. The Steward Street School Experiment: A Critical Case Study of Possibilities

    ERIC Educational Resources Information Center

    Burke, Catherine; Grosvenor, Ian

    2013-01-01

    This article presents a critical case study of an inner city state school that for a decade (1940s-1950s) attracted the interest of a wide contingency of educationalists, policy makers, researchers, artists and various press and film media. It has been argued that if we are to progress "social alternatives" in education, researchers need to…

  12. What Matters in College to Students: Critical Incidents in the Undergraduate Experience

    ERIC Educational Resources Information Center

    Vianden, Jörg

    2015-01-01

    This article advances that undergraduates are partners to higher education institutions in establishing the educational enterprise. Leaning on student relationship management as a theoretical construct and the critical incident technique as method, the study found 58 undergraduates' interpersonal interactions with faculty, staff, and peers…

  13. ACCELERATION OF LOS ALAMOS NATIONAL LABORATORY TRANSURANIC WASTE DISPOSITION

    SciTech Connect

    O'LEARY, GERALD A.

    2007-01-04

    Energy Los Alamos Site Office, Carlsbad Field Office and the Department of Energy Headquaeters. Rather than simply processing containers as retrieved, the plan places priority on efficient curie disposition, a direct correlation to reducing risk. Key elements of the approch include balancing inventory and operational risks, tailoring methods to meet requirements, optimizing existing facilities, equipment and staff, and incorporating best practices from other Department of Energy sites. With sufficient funding this will enable LANL to ship the above-ground high activity contact-handled transuranic waste offsite by the end of Fiscal Year (FY) 2007 and to disposition the remaining above- and below-ground contact-handled and remote-handled transuranic waste inventory by December 2010. Nearly 70% of the contact-handled transuranic waste containers, including the high activity waste, require processing and repackaging before characterization and certification for shipment to the Waste Isolation Pilot Plant. LANL is employing a balanced risk approach that accomplishes significant long-term risk reduction by accepting short-term increased facility operations risk under well-developed and justified interim controls. Reviews of facility conditions and additional analyses show that the Waste Characterization, Reduction and Repackaging Facility and the Radioassay and Nondestructive Testing Facility are the most appropriate facilities to safetly remediate, repackage, and ship lower activity and the remaining high activity drums. Updated safety documentation supporting limited Hazard Category 2 operations in these facilities has been developed. Once approved, limited-term operations to process the high activity drums can begin in early 2007, building upon the experience base established performing Hazard Category 3 operations processing lower activity waste in these facilities. LANL is also implementing a series of actions to improve and sustain operations for processing contact

  14. Effects of Diversity Experiences on Critical Thinking Skills over 4 Years of College

    ERIC Educational Resources Information Center

    Pascarella, Ernest T.; Martin, Georgianna L.; Hanson, Jana M.; Trolian, Teniell L.; Gillig, Benjamin; Blaich, Charles

    2014-01-01

    The benefits of student engagement in diversity experiences on a range of college outcomes have been well documented. However, the potential influence of involvement in diversity experiences during college on the cognitive and intellectual outcomes of post-secondary education is only beginning to be understood. Gurin et al. (2002) made a…

  15. HBCUs as Critical Context for Identity Work: Reflections, Experiences, and Lessons Learned

    ERIC Educational Resources Information Center

    Greenfield, Derek F.; Innouvong, Tony; Aglugub, Richard Jay; Yusuf, Ismail A.

    2015-01-01

    Using narratives from a diverse group of students and staff in terms of race and religion, this chapter gives voice to these individuals' experiences with issues of diversity and inclusion at an HBCU. This chapter also discusses how these experiences helped to facilitate the authors' racial and cultural identity development.

  16. Sunset at the ALaMO

    NASA Video Gallery

    A new color all-sky camera has opened its eyes at the ALaMO, or Automated Lunar and Meteor Observatory, at NASA's Marshall Space Flight Center in Huntsville, Ala. Watch its inaugural video below, s...

  17. Environmental surveillance at Los Alamos during 1994

    SciTech Connect

    1996-07-01

    This report describes environmental monitoring activities at Los Alamos National Laboratory for 1994. Data were collected to assess external penetrating radiation, airborne emissions, liquid effluents, radioactivity of environmental materials and food stuffs, and environmental compliance.

  18. New Rad Lab for Los Alamos

    ScienceCinema

    None

    2010-01-08

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  19. Publications of Los Alamos research 1988

    SciTech Connect

    Varjabedian, K.; Dussart, S.A.; McClary, W.J.; Rich, J.A.

    1989-12-01

    This bibliography lists unclassified publications of work done at the Los Alamos National Laboratory for 1988. The entries, which are subdivided by broad subject categories, are cross-referenced with an author index and a numeric index.

  20. New Rad Lab for Los Alamos

    SciTech Connect

    2008-08-06

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  1. Analysis of Np-237 ENDF for the theortical interpretation of critical assembly experiments.

    SciTech Connect

    Mihaila, B.; Chadwick, M. B.; MacFarlane, R. E.; Kawano, T.

    2004-01-01

    We report on the present status of our effort toward an improved Np-237 evaluated nuclear data file (ENDF). The aim here is to bridge the gap between calculated and observed k-eff values, as measured at the Np-U critical assembly at LANL, TA-18. As such, we perform a critical analysis of the existing body of experimental data and recommended evaluations. We are targeting in principal the fission nu-bar and cross section in Np-237, as well as the inelastic scattering which is particularly important since Np-237 is a threshold fissioner. This analysis will be employed in a future sensitivity study of the calculated k-eff with respect to variations of the afore mentioned nuclear data.

  2. Generation of thin, near critical density gas targets for laser plasma interaction experiments

    NASA Astrophysics Data System (ADS)

    Salehi, Fatholah; Goers, Andy; Hine, George; Feder, Linus; Miao, Bo; Milchberg, Howard

    2015-11-01

    We present the design and characterization of a thin (200µm FWHM), high density pulsed gas jet which we use to study near critical and overcritical laser plasma interactions. We show that cryogenic cooling of the pulsed jet provides the necessary density enhancement for reaching overcritical plasma densities at 800 nm (> 1 . 7 × >102 1 cm-3) with pure hydrogen gas at plenum pressures below 1000 psi. Further, we present 2D and 3D PIC simulations showing the interaction of femtosecond pulses with our experimentally measured near critical gas density profile. The simulations show electron and ion acceleration at drive pulse energies as low as a few tens of millijoules. This work supported by DTRA and the US Department of Energy.

  3. Edward Teller Returns to LOS Alamos

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.

    2010-01-01

    I was asked to share some reflections of Edward Teller's return to Los Alamos during my directorship. I met Teller late in his life. My comments focus on that time and they will be mostly in the form of stories of my interactions and those of my colleagues with Teller. Although the focus of this symposium is on Teller's contributions to science, at Los Alamos it was never possible to separate Teller's science from policy and controversy ...

  4. Internship at Los Alamos National Laboratory

    SciTech Connect

    Dunham, Ryan Q.

    2012-07-11

    Los Alamos National Laboratory (LANL) is located in Los Alamos, New Mexico. It provides support for our country's nuclear weapon stockpile as well as many other scientific research projects. I am an Undergraduate Student Intern in the Systems Design and Analysis group within the Nuclear Nonproliferation division of the Global Security directorate at LANL. I have been tasked with data analysis and modeling of particles in a fluidized bed system for the capture of carbon dioxide from power plant flue gas.

  5. Los Alamos Laser Eye Investigation.

    SciTech Connect

    Odom, C. R.

    2005-01-01

    A student working in a laser laboratory at Los Alamos National Laboratory sustained a serious retinal injury to her left eye when she attempted to view suspended particles in a partially evacuated target chamber. The principle investigator was using the white light from the flash lamp of a Class 4 Nd:YAG laser to illuminate the particles. Since the Q-switch was thought to be disabled at the time of the accident, the principal investigator assumed it would be safe to view the particles without wearing laser eye protection. The Laboratory Director appointed a team to investigate the accident and to report back to him the events and conditions leading up to the accident, equipment malfunctions, safety management causal factors, supervisory and management action/inaction, adequacy of institutional processes and procedures, emergency and notification response, effectiveness of corrective actions and lessons learned from previous similar events, and recommendations for human and institutional safety improvements. The team interviewed personnel, reviewed documents, and characterized systems and conditions in the laser laboratory during an intense six week investigation. The team determined that the direct and primary failures leading to this accident were, respectively, the principle investigator's unsafe work practices and the institution's inadequate monitoring of worker performance. This paper describes the details of the investigation, the human and institutional failures, and the recommendations for improving the laser safety program.

  6. Temperature Gradients on the Cell Wall in the Critical Viscosity Experiment

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Moldover, Michael R.

    1993-01-01

    Because of the diverging susceptibility delta rho/delta Tau near the liquid-vapor critical point, temperature gradients must be kept small to maintain adequate sample homogeneity. In our Science Requirements Document we paid particular attention to radial density gradients caused by equilibration of the xenon sample. Axial density gradients were addressed through the requirement that the cell's copper wall have a gradient less than 22 microK/m. This report re-examines the cell wall's temperature distribution in more detail by estimating all known significant contributions to temperature differences on the cell's wall.

  7. ISS-Crystal Growth of Photorefractive Materials (BSO): Critical Design Issues for Optimized Data Extraction from Space Experiments

    NASA Technical Reports Server (NTRS)

    Hyers, Robert W.; Motakef, S.; Witt, A. F.; Wuensch, B.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Realization of the full potential of photorefractive materials in device technology is seriously impeded by our inability to achieve controlled formation of critical defects during single crystal growth and by difficulties in meeting the required degree of compositional uniformity on a micro-scale over macroscopic dimensions. The exact nature and origin of the critical defects which control photorefractivity could not as yet be identified because of gravitational interference. There exists, however, strong evidence that the density of defect formation and their spatial distribution are adversely affected by gravitational interference which precludes the establishment of quantifiable and controllable heat and mass transfer conditions during crystal growth. The current, NASA sponsored research at MIT is directed at establishing a basis for the development of a comprehensive approach to the optimization of property control during melt growth of photorefractive materials, making use of the m-g environment, provided in the International Space Station. The objectives to be pursued in m-g research on photorefractive BSO (Bi12SiO20) are: (a) identification of the x-level(s) responsible for photorefractivity in undoped BSO; (b) development of approaches leading to the control of x-level formation at uniform spatial distribution; (c) development of doping and processing procedures for optimization of the critical, application specific parameters, spectral response, sensitivity, response time and matrix stability. The presentation will focus on: the rationale for the justification of the space experiment, ground-based development efforts, design considerations for the space experiments, strategic plan of the space experiments, and approaches to the quantitative analysis of the space experiments.

  8. Swimming without the water: a critical perspective on mental health experience for adult nursing students.

    PubMed

    Barrett, Paul; Jackson, Andrew

    2013-11-01

    Adult nurses and adult field nursing students come into contact with a diverse range of other patient groups in their practice but perhaps none more so than those who have co-existing mental health issues. Consequently adult field student nurses must be equipped with the requisite knowledge and skills to competently care for their patients who also experience mental health problems. Given the pressure on placements many education providers have developed alternatives to direct mental health experiences. The authors review their own experience of some of the modalities that higher education institutes (HEI) use to instruct their students in this field. They argue that, ideally, there is no substitute for the practical experience of placements in the mental health sector, particularly if these include contact with mental health nursing. The paper concludes with some recommendations for nursing education and our professional body that could help equip adult field nursing students with the necessary experience and skills of mental health to support them into their future careers. PMID:23830557

  9. Critical view to ``IGEX 76Ge neutrinoless double-beta decay experiment: Prospects for next generation experiments''

    NASA Astrophysics Data System (ADS)

    Klapdor-Kleingrothaus, H. V.; Dietz, A.; Krivosheina, I. V.

    2004-10-01

    Recently, a paper entitled “The IGEX 76Ge neutrinoless double-beta decay experiment: Prospects for next generation experiments” has been published [

    Phys. Rev. D 65, 092007 (2002)PRVDAQ0556-282110.1103/PhysRevD.65.092007
    ]. In view of the recently reported evidence for neutrinoless double-beta decay [
    Mod. Phys. Lett. A 16, 2409 (2001).MPLAEQ0217-732310.1142/S0217732301005825
    ;
    Found. Phys.FNDPA40015-9018 31, 1181 (2002)
    ;
    Phys. Lett. BPYLBAJ0370-2693 586, 198 (2004).10.1016/j.physletb.2004.02.025
    ], it is particularly unfortunate that the IGEX paper is rather incomplete in its presentation. We would like to point out in this Comment that and why it would be highly desirable to make more details about the experimental conditions and the analysis of IGEX available. We list some of the main points, which require further explanation. We also point to an arithmetic mistake in the analysis of the IGEX data, the consequence of which are too high half-life limits given in that paper.

  10. Experience of critical incident stress among ambulance service staff and relationship to psychological symptoms.

    PubMed

    Gallagher, Sharon; McGilloway, Sinéad

    2009-01-01

    This two-stage study was undertaken to assess the extent and nature of Critical Incident Stress (CIS) amongst frontline staff in a large ambulance service in Ireland. In Stage One, 63% (112/180) of participants completed a Screening Questionnaire and the GHQ-12. In Stage Two, 27 participants, who had experienced a critical incident (CI) during the previous year completed several measures to assess PTSD symptomatology, burnout, health-related Quality of Life, and dispositional optimism. Eighty-one per cent (80/94) of the Stage One group reported that their health had been affected by a CI; 42% (44/106) were identified as 'cases' on the GHQ-12. Stage Two results indicated that 12 participants had PTSD symptoms while this entire group showed moderate levels of emotional exhaustion and depersonalization, despite experiencing high levels of personal accomplishment and optimism. The findings suggest a high prevalence of CIS among ambulance personnel in Ireland and a significant impact on overall health and wellbeing. This has important implications for the effective management of CIS and suggests an important role for occupational health and organizational psychologists in providing routine support to ambulance service staff andpossibly other emergency services personnel. PMID:20524508

  11. Accelerators for critical experiments involving single-particle upset in solid-state microcircuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1985-01-01

    Charged-particle interactions in microelectronic circuit chips (integrated circuits) present a particularly insidious problem for solid-state electronic systems due to the generation of soft errors or single-particle event upset (SEU) by either cosmic rays or other radiation sources. Particle accelerators are used to provide both light and heavy ions in order to assess the propensity of integrated circuit chips for SEU. Critical aspects of this assessment involve the ability to analytically model SEU for the prediction of error rates in known radiation environments. In order to accurately model SEU, the measurement and prediction of energy deposition in the form of an electron-hole plasma generated along an ion track is of paramount importance. This requires the use of accelerators which allow for ease in both energy control (change of energy) and change of ion species. This and other aspects of ion-beam control and diagnostics (e.g., uniformity and flux) are of critical concern for the experimental verification of theoretical SEU models.

  12. Validation of HELIOS Neutron Cross-Section Library for RBMK Reactors Against the Data From the Critical Facility Experiments

    SciTech Connect

    Jasiulevicius, Audrius; Sehgal, Bal Raj

    2002-07-01

    The RBMK reactors are channel type, water-cooled and graphite moderated reactors. The first RBMK type electricity production reactor was put on-line in 1973. Currently there are 13 operating reactors of this type. Two of the RBMK-1500 reactors are at the Ignalina NPP in Lithuania. Experimental Critical Facility for RBMK reactors, located at Kurchatov Institute, Moscow was designed to carry out critical reactivity experiments on assemblies, which imitate parts of the RBMK reactor core. The facility is composed of Control and Protection Rods (CPR's), fuel assemblies with different enrichment in U-235 and other elements, typical for RBMK reactor core loadings, e.g. additional absorber assemblies, CPR imitators, etc. A simulation of a set of the experiments, performed at the Experimental Critical Facility, was carried out at the Royal Institute of Technology (RIT), Nuclear Power Safety Division, using CORETRAN 3-D neutron dynamics code. The neutron cross sections for assemblies were calculated using HELIOS code. The aim of this work was to evaluate capabilities of the HELIOS code to provide correct cross section data for the RBMK reactor. The calculation results were compared to the similar CORETRAN calculations, when employing WIMS-D4 code generated cross section data. For some of the experiments, where calculation results with CASMO-4 code generated cross sections are available, the comparison is also performed against CASMO-4 results. Eleven different experiments were simulated. Experiments differ in size of the facility core (number of assemblies loaded): from simple core loadings, composed only of a few fuel assemblies, to complicated configurations, which represent a part of the RBMK reactor core. Diverse types of measurements were carried out during these experiments: reactivity, neutron flux distributions (both axial and radial), rod reactivity worth and the voiding effects. Results of the reactivity measurements and relative neutron flux distributions were

  13. Community College Students' Experiences with Financial Aid Policies and Practices: A Critical Case Study

    ERIC Educational Resources Information Center

    White, Julie A.

    2013-01-01

    This case study describes community college students' experiences with governmental financial aid policies and institutional financial aid processes at an urban community college campus in the Northeastern United States. Drawing from theories of social justice, conceptions of social capital, and institutionalist analyses of the community…

  14. Congruency between Student Interns and Worksite Supervisors Regarding Critical Elements of an Internship Experience.

    ERIC Educational Resources Information Center

    Henry, Janice S.; Rehwaldt, Susan S.; Vineyard, George M.

    2001-01-01

    Comparison was made of 39 student interns' and 30 worksite supervisors' identification of the importance of 15 academic elements and 9 worksite elements to all interns and to their own recent internship experiences. Different rankings of general and particular elements among students, among employers, and between the groups can help identify…

  15. Critical Race Reflections: Valuing the Experiences of Teachers of Color in Teacher Education

    ERIC Educational Resources Information Center

    Kohli, Rita

    2009-01-01

    While research has demonstrated that White teachers often must be taught about the pain of racism in order to not perpetuate it, this may not apply to racial minority teachers. Through personal experience, Teachers of Color are likely aware of the trauma that racism can cause students. Within teacher education, we must create research and teaching…

  16. Enhancing Critical Consciousness through a Cross-Cultural Immersion Experience in South Africa

    ERIC Educational Resources Information Center

    Choi, Kyoung Mi; VanVoorhis, Richard W.; Ellenwood, Audrey E.

    2015-01-01

    Using phenomenological approaches, the author explored the meanings and essences of a cross-cultural immersion experience in South Africa among counseling master's-level students. Five core themes--the meaning of being American, sociopolitical awareness, engagement with South Africans and their communities, appreciation of life, and commitment to…

  17. Is This a Meaningful Learning Experience? Interactive Critical Self-Inquiry as Investigation

    ERIC Educational Resources Information Center

    Allard, Andrea C.; Gallant, Andrea

    2012-01-01

    What conditions enable educators to engage in meaningful learning experiences with peers and beginning practitioners? This article documents a self-study on our actions-in-practice in a peer mentoring project. The investigation involved an iterative process to improve our knowledge as teacher educators, reflective practitioners, and researchers.…

  18. Are Sojourners Natural Comparativists? Critical Perspectives on the Learning Experiences of International Students

    ERIC Educational Resources Information Center

    Schweisfurth, Michele

    2012-01-01

    Students who spend a period of time studying outside of their own national systems have a number of advantages in terms of developing a comparative perspective on education. The experience of living and studying abroad provides them with the opportunity to act as participant observers of at least two different systems, and the natural…

  19. Cumulative experiences with life adversity: Identifying critical levels for targeting prevention efforts

    PubMed Central

    Mitchell, Kimberly J.; Tynes, Brendesha; Umaña-Taylor, Adriana J.; Williams, David

    2015-01-01

    This paper aims to assess the role of individual types and cumulative life adversity for understanding depressive symptomatology and aggressive behavior. Data were collected in 2011 as part of the Teen Life Online and in Schools Study from 916 ethnically-diverse students from 12 middle, K-8, 6-12 and high schools in the Midwest United States. Youth reported an average of 4.1 non-victimization adversities and chronic stressors in their lifetimes. There was a linear relationship between number of adversities and depression and aggression scores. Youth reporting the highest number of adversities (7 or more) had significantly higher depression and aggression scores than youth reporting any other number of adversities suggesting exposure at this level is a critical tipping point for mental health concerns. Findings underscore an urgent need to support youth as they attempt to negotiate, manage, and cope with adversity in their social worlds. PMID:26057876

  20. Experiences with Extra-Vehicular Activities in Response to Critical ISS Contingencies

    NASA Technical Reports Server (NTRS)

    Van Cise, Edward A.; Kelly, Brian J.; Radigan, Jeffery P.; Cranmer, Curtis W.

    2016-01-01

    Initial "Big 14" work was put to the test for the first time in 2010. Deficiencies were found in some of the planning and approaches to that work; Failure Response Assessment Team created in 2010 to address deficiencies -Identify and perform engineering analysis in operations products prior to failure; incorporate results into operations products -Identify actions for protecting ISS against a Next Worse Failure after the first failure occurs -Better document not only EVA products but also planning products, assumptions, and open actions; Pre-failure investments against critical failures best postures ISS for swift response and recovery -A type of insurance policy -Has proven effective in a number of contingency EVA cases since 2010. Planning for MBSU R&R in 2012, Second PM R&R in 2013, EXT MDM R&R in 2014; Current FRAT schedule projects completion of all analysis in 2018

  1. Flow-Boiling Critical Heat Flux Experiments Performed in Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Hasan, Mohammad M.; Mudawar, Issam

    2005-01-01

    Poor understanding of flow boiling in microgravity has recently emerged as a key obstacle to the development of many types of power generation and advanced life support systems intended for space exploration. The critical heat flux (CHF) is perhaps the most important thermal design parameter for boiling systems involving both heatflux-controlled devices and intense heat removal. Exceeding the CHF limit can lead to permanent damage, including physical burnout of the heat-dissipating device. The importance of the CHF limit creates an urgent need to develop predictive design tools to ensure both the safe and reliable operation of a two-phase thermal management system under the reduced-gravity (like that on the Moon and Mars) and microgravity environments of space. At present, very limited information is available on flow-boiling heat transfer and the CHF under these conditions.

  2. Cumulative experiences with life adversity: Identifying critical levels for targeting prevention efforts.

    PubMed

    Mitchell, Kimberly J; Tynes, Brendesha; Umaña-Taylor, Adriana J; Williams, David

    2015-08-01

    This paper aims to assess the role of individual types and cumulative life adversity for understanding depressive symptomatology and aggressive behavior. Data were collected in 2011 as part of the Teen Life Online and in Schools Study from 916 ethnically-diverse students from 12 middle, K-8, 6-12 and high schools in the Midwest United States. Youth reported an average of 4.1 non-victimization adversities and chronic stressors in their lifetimes. There was a linear relationship between number of adversities and depression and aggression scores. Youth reporting the highest number of adversities (7 or more) had significantly higher depression and aggression scores than youth reporting any other number of adversities suggesting exposure at this level is a critical tipping point for mental health concerns. Findings underscore an urgent need to support youth as they attempt to negotiate, manage, and cope with adversity in their social worlds. PMID:26057876

  3. Microstructure, critical current density and trapped field experiments in IG-processed Y-123

    NASA Astrophysics Data System (ADS)

    Muralidhar, M.; Ide, N.; Koblischka, M. R.; Diko, P.; Inoue, K.; Murakami, M.

    2016-05-01

    In this paper, we adapted the top-seeded infiltration growth ‘IG’ technique and produced several YBa2Cu3O y ‘Y-123’ samples with an addition of Y2BaCuO5 ‘Y-211’ secondary phase particles with varying sizes by the sintering process and the ball milling technique. For the first set of samples, Y-211 disks were sintered at temperatures ranging between 900 °C and 1100 °C and were used for the production of Y-123 material by the IG process. Magnetization measurements showed a sharp superconducting transition with an onset T c at around 92 K, irrespective of the sintering temperature. However, the trapped field and critical current density (J c) values were dependent on the sintering temperature and it was found that the best temperature is around 925 °C. Further, the trapped field distribution measurements at 77 K indicated that all samples are of single grain nature. The highest trapped field was recorded around 0.31 T at 77 K for the Y-123 sample with 20 mm in diameter and 5 mm thickness produced by Y-211 pre-from around 925 °C. On the other hand, a second set of samples Y-211 were controlled by ball milling technique combined with an optimized slow cooling process. As a result, the critical current density (J c) at 77 K and zero field was determined to be 225 kA cm-2. The improved performance of the Y-123 material can be understood in terms of homogeneous distribution of fine secondary phase particles which is demonstrated by AFM micrographs.

  4. Doctors’ and nurses’ views and experience of transferring patients from critical care home to die: A qualitative exploratory study

    PubMed Central

    Coombs, Maureen; Darlington, Anne-Sophie; Richardson, Alison

    2015-01-01

    Background: Dying patients would prefer to die at home, and therefore a goal of end-of-life care is to offer choice regarding where patients die. However, whether it is feasible to offer this option to patients within critical care units and whether teams are willing to consider this option has gained limited exploration internationally. Aim: To examine current experiences of, practices in and views towards transferring patients in critical care settings home to die. Design: Exploratory two-stage qualitative study Setting/participants: Six focus groups were held with doctors and nurses from four intensive care units across two large hospital sites in England, general practitioners and community nurses from one community service in the south of England and members of a Patient and Public Forum. A further 15 nurses and 6 consultants from critical care units across the United Kingdom participated in follow-on telephone interviews. Findings: The practice of transferring critically ill patients home to die is a rare event in the United Kingdom, despite the positive view of health care professionals. Challenges to service provision include patient care needs, uncertain time to death and the view that transfer to community services is a complex, highly time-dependent undertaking. Conclusion: There are evidenced individual and policy drivers promoting high-quality care for all adults approaching the end of life encompassing preferred place of death. While there is evidence of this choice being honoured and delivered for some of the critical care population, it remains debatable whether this will become a conventional practice in end of life in this setting. PMID:25519147

  5. From Memory Impairment to Posttraumatic Stress Disorder-Like Phenotypes: The Critical Role of an Unpredictable Second Traumatic Experience.

    PubMed

    Finsterwald, Charles; Steinmetz, Adam B; Travaglia, Alessio; Alberini, Cristina M

    2015-12-01

    Arousal and stress critically regulate memory formation and retention. Increasing levels of stress produce an inverted U-shaped effect on cognitive performance, including the retention of explicit memories, and experiencing a severe stress during a traumatic event may lead to posttraumatic stress disorder (PTSD). The molecular mechanisms underlying the impairing effect of a severe stress on memory and the key contribution of traumatic experiences toward the development of PTSD are still unknown. Here, using increasing footshock intensities in an inhibitory avoidance paradigm, we reproduced the inverted U-shaped curve of memory performance in rats. We then show that the inverted U profile of memory performance correlates with an inverted U profile of corticosterone level in the circulation and of brain-derived neurotrophic factor, phosphorylated tropomyosin-receptor kinase B, and methyl CpG binding protein in the dorsal hippocampus. Furthermore, training with the highest footshock intensity (traumatic experience) led to a significant elevation of hippocampal glucocorticoid receptors. Exposure to an unpredictable, but not to a predictable, highly stressful reminder shock after a first traumatic experience resulted in PTSD-like phenotypes, including increased memory of the trauma, high anxiety, threat generalization, and resistance to extinction. Systemic corticosterone injection immediately after the traumatic experience, but not 3 d later, was sufficient to produce PTSD-like phenotypes. We suggest that, although after a first traumatic experience a suppression of the corticosterone-dependent response protects against the development of an anxiety disorder, experiencing more than one trauma (multiple hits) is a critical contributor to the etiology of PTSD. PMID:26631471

  6. From Memory Impairment to Posttraumatic Stress Disorder-Like Phenotypes: The Critical Role of an Unpredictable Second Traumatic Experience

    PubMed Central

    Finsterwald, Charles; Steinmetz, Adam B.; Travaglia, Alessio

    2015-01-01

    Arousal and stress critically regulate memory formation and retention. Increasing levels of stress produce an inverted U-shaped effect on cognitive performance, including the retention of explicit memories, and experiencing a severe stress during a traumatic event may lead to posttraumatic stress disorder (PTSD). The molecular mechanisms underlying the impairing effect of a severe stress on memory and the key contribution of traumatic experiences toward the development of PTSD are still unknown. Here, using increasing footshock intensities in an inhibitory avoidance paradigm, we reproduced the inverted U-shaped curve of memory performance in rats. We then show that the inverted U profile of memory performance correlates with an inverted U profile of corticosterone level in the circulation and of brain-derived neurotrophic factor, phosphorylated tropomyosin-receptor kinase B, and methyl CpG binding protein in the dorsal hippocampus. Furthermore, training with the highest footshock intensity (traumatic experience) led to a significant elevation of hippocampal glucocorticoid receptors. Exposure to an unpredictable, but not to a predictable, highly stressful reminder shock after a first traumatic experience resulted in PTSD-like phenotypes, including increased memory of the trauma, high anxiety, threat generalization, and resistance to extinction. Systemic corticosterone injection immediately after the traumatic experience, but not 3 d later, was sufficient to produce PTSD-like phenotypes. We suggest that, although after a first traumatic experience a suppression of the corticosterone-dependent response protects against the development of an anxiety disorder, experiencing more than one trauma (multiple hits) is a critical contributor to the etiology of PTSD. SIGNIFICANCE STATEMENT Increasing levels of stress produce an inverted U-shaped effect on memory retention. Humans experiencing an acute trauma may develop posttraumatic stress disorder (PTSD), but the key

  7. Automated workflows for critical time-dependent calibrations at the CMS experiment

    NASA Astrophysics Data System (ADS)

    Cerminara, G.; van Besien, B.

    2015-12-01

    Fast and efficient methods for the calibration and the alignment of the detector are a key asset to exploit the physics potential of the Compact Muon Solenoid (CMS) detector and to ensure timely preparation of results for conferences and publications. To achieve this goal, the CMS experiment has set up a powerful framework. This includes automated workflows in the context of a prompt calibration concept, which allows for a quick turnaround of the calibration process following as fast as possible any change in running conditions. The presentation will review the design and operational experience of these workflows and the related monitoring system during the LHC Run I and focus on the development, deployment and commissioning in preparation of Run II.

  8. Critical transition for the edge shear layer formation: Comparison of model and experiment

    SciTech Connect

    Carreras, B. A.; Garcia, L.; Pedrosa, M. A.; Hidalgo, C.

    2006-12-15

    The experimental results for the emergence of the plasma edge shear flow layer in TJ-II [C. Alehaldre et al.Fusion Technol. 17, 131 (1990)] can be explained using a simple model for a second-order transition based on the sheared flow amplification by Reynolds stress and turbulence suppression by shearing. In the dynamics of the model, the resistive interchange instability is used. This model gives power dependence on density gradients before and after the transition, consistent with experiment.

  9. Laser protective eyewear program at the Los Alamos Scientific Laboratory

    SciTech Connect

    Winburn, D.C.

    1980-01-01

    The proliferation of lasers at Los Alamos focused considerable attention on providing adequate eye protection for experimenters involved in the use of a wide variety of nonionizing radiation. Experiments with fast-pulsed lasers (Nd:YAG, HF, and CO/sub 2/) were performed to gain biological threshold data on ocular damage. In parallel, eye protection devices were evaluated, which resulted in the development of lightweight, comfortable spectacles of colored glass filters that can be ground to prescription specifications. Goggle styles are employed in specific applications.

  10. Auditing nuclear weapons quality programs at Los Alamos

    SciTech Connect

    Davis, A.H.

    1988-01-01

    Some of the problems involved in introducing quality assurance on a broad scale in a national laboratory are discussed. A philosophy of how QA can be utilized beneficially in research and development activities is described briefly, and our experiences at Los Alamos in applying QA to nuclear weapons activities are outlines. The important role of audits is emphasized; audits are used not merely to determine the effectiveness of QA programs but also to explain and demonstrate the usefulness of QA to a generally sceptical body of engineers and scientists. Finally, some ways of easing the application of QA in the future are proposed. 1 ref.

  11. Criticality safety training

    SciTech Connect

    Woodruff, S.K.

    1997-06-01

    Criticality safety training is an important element of the Plutonium Facility safety program at Los Alamos National Laboratory. Training consists of student self-study handbooks and hands-on performance-based training in a mock-up laboratory containing gloveboxes, trolley conveyor system, and self-monitoring instruments. A 10-minute video tape and lecture was presented to describe how training in this area is conducted.

  12. The Supporting Role of Mesocosm-Scale Laboratory Experiments in Solving Critical Issues at Hydrogeological Research Sites

    NASA Astrophysics Data System (ADS)

    Schincariol, R.; Nagare, R.; Quinton, W.; Hayashi, M.

    2008-12-01

    Hydrogeological research sites provide a unique opportunity to study parameters and processes at the field scale. However, the most successful long-term research sites have been coupled with laboratory-scale experiments and numerical modeling studies. Mesocosm-scale laboratory experiments allow the investigation of local-scale hydrogeological processes often with sensors that exceed the spatial, temporal, and accuracy of field based monitoring. After over two years of design and construction a unique mesocosm-scale hydrogeological climate chamber was emplaced at the University of Western Ontario Biotron facility in April 2008. What makes this chamber different from other ecohydrological chambers is the ability to reproduce the subarctic solar and atmospheric environment and house soil monoliths up to 1.5 m in diameter and 4 m in height. Of particular importance is the ability to subject soil monoliths, inclusive of vegetation, to climate forcing experiments (varying solar energy, air temperature, precipitation, wind, CO2) while continuously monitoring liquid, gas, and energy fluxes. At present, experiments on 60 cm diameter by 90 cm deep peat / permafrost cores from our central Mackenzie River basin long-term field site are being conducted to better elucidate moisture and carbon transport processes occurring in the active layer. These climate forcing laboratory based experiments will be closely integrated with on-going field studies in the basin. Through this research we will be able to develop a physically-based numerical model to estimate the volume and timing of runoff from wetland-dominated basins in discontinuous permafrost. The experiments will answer critical questions, not addressable by field data alone, on how subarctic ecosystems will respond to climate change. We would also like to foster collaborations to address other scientific questions utilizing the climate chamber. In particular, experiments in support of pilot scale remediation efforts in cold

  13. Defect printability of ArF alternative phase-shift mask: a critical comparison of simulation and experiment

    NASA Astrophysics Data System (ADS)

    Ozawa, Ken; Komizo, Tooru; Ohnuma, Hidetoshi

    2002-07-01

    An alternative phase shift mask (alt-PSM) is a promising device for extending optical lithography to finer design rules. There have been few reports, however, on the mask's ability to identify phase defects. We report here an alt-PSM of a single-trench type with undercut for ArF exposure, with programmed phase defects used to evaluate defect printability by measuring aerial images with a Zeiss MSM193 measuring system. The experimental results are simulated using the TEMPEST program. First, a critical comparison of the simulation and the experiment is conducted. The actual measured topographies of quartz defects are used in the simulation. Moreover, a general simulation study on defect printability using an alt-PSM for ArF exposure is conducted. The defect dimensions, which produce critical CD errors, are determined by simulation that takes into account the full 3-dimensional structure of phase defects as well as a simplified structure. The critical dimensions of an isolated bump defect identified by the alt-PSM of a single-trench type with undercut for ArF exposure are 300 nm in bottom dimension and 74 degrees in height (phase) for the real shape, where the depth of wet-etching is 100 nm and the CD error limit is +/- 5 percent.

  14. Three-Dimensional Electromagnetic Monte Carlo Particle-in-Cell Simulations of Critical Ionization Velocity Experiments in Space

    NASA Technical Reports Server (NTRS)

    Wang, J.; Biasca, R.; Liewer, P. C.

    1996-01-01

    Although the existence of the critical ionization velocity (CIV) is known from laboratory experiments, no agreement has been reached as to whether CIV exists in the natural space environment. In this paper we move towards more realistic models of CIV and present the first fully three-dimensional, electromagnetic particle-in-cell Monte-Carlo collision (PIC-MCC) simulations of typical space-based CIV experiments. In our model, the released neutral gas is taken to be a spherical cloud traveling across a magnetized ambient plasma. Simulations are performed for neutral clouds with various sizes and densities. The effects of the cloud parameters on ionization yield, wave energy growth, electron heating, momentum coupling, and the three-dimensional structure of the newly ionized plasma are discussed. The simulations suggest that the quantitative characteristics of momentum transfers among the ion beam, neutral cloud, and plasma waves is the key indicator of whether CIV can occur in space. The missing factors in space-based CIV experiments may be the conditions necessary for a continuous enhancement of the beam ion momentum. For a typical shaped charge release experiment, favorable CIV conditions may exist only in a very narrow, intermediate spatial region some distance from the release point due to the effects of the cloud density and size. When CIV does occur, the newly ionized plasma from the cloud forms a very complex structure due to the combined forces from the geomagnetic field, the motion induced emf, and the polarization. Hence the detection of CIV also critically depends on the sensor location.

  15. The first critical experiment with a LEU Russian fuel IRT-4M at the training reactor VR-1

    SciTech Connect

    Frybort, Jan

    2008-07-15

    A critical experiment is a standard part of training of students at the Training Reactor VR-1 operated within the Faculty of Nuclear Sciences and Physical Engineering at the Czech Technical University in Prague. In autumn 2005 the HEU fuel IRT-3M with enrichment 36 % {sup 235}U was replaced by the LEU fuel IRT-4M with enrichment 19.7 % {sup 235}U. The fuel replacement at the VR-1 Reactor is a part of an international program RERTR. This Paper presents basic information about preparation for the fuel replacement and approaching of the first critical state with the new zone configuration C1 which replaced B1 core with the old IRT-3M fuel. The whole process was carried out according to the Czech law and the relevant international recommendations. The experience with the VR-1 operation confirms the assumption that the C1 core configuration will be suitable from the point of view of the reactivity balance for the long term safe operation of the Training Reactor VR-1. (author)

  16. ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

    SciTech Connect

    G. Palmiotti

    2011-12-01

    The ENDF/B-VII.1 library is the latest revision to the United States' Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 418 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [1]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected 235U and 239Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for selected actinide reaction rates such as 236U capture. Other deficiencies, such as the overprediction of Pu solution system critical eigenvalues and a decreasing trend in calculated eigenvalue for

  17. ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

    NASA Astrophysics Data System (ADS)

    Kahler, A. C.; MacFarlane, R. E.; Mosteller, R. D.; Kiedrowski, B. C.; Frankle, S. C.; Chadwick, M. B.; McKnight, R. D.; Lell, R. M.; Palmiotti, G.; Hiruta, H.; Herman, M.; Arcilla, R.; Mughabghab, S. F.; Sublet, J. C.; Trkov, A.; Trumbull, T. H.; Dunn, M.

    2011-12-01

    The ENDF/B-VII.1 library is the latest revision to the United States' Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [M. B. Chadwick et al., "ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data," Nuclear Data Sheets, 112, 2887 (2011)]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected 235U and 239Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for selected

  18. ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

    SciTech Connect

    Kahler, A.C.; Herman, M.; Kahler,A.C.; MacFarlane,R.E.; Mosteller,R.D.; Kiedrowski,B.C.; Frankle,S.C.; Chadwick,M.B.; McKnight,R.D.; Lell,R.M.; Palmiotti,G.; Hiruta,H.; Herman,M.; Arcilla,R.; Mughabghab,S.F.; Sublet,J.C.; Trkov,A.; Trumbull,T.H.; Dunn,M.

    2011-12-01

    The ENDF/B-VII.1 library is the latest revision to the United States Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [M. B. Chadwick et al., 'ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data,' Nuclear Data Sheets, 112, 2887 (2011)]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected {sup 235}U and {sup 239}Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for

  19. Solar pond research at the Los Alamos National Laboratory

    SciTech Connect

    Jones, G.F.; Meyer, K.A.; Hedstrom, J.C.; Grimmer, D.P.

    1984-01-01

    A description of solar pond research at Los Alamos National Laboratory is presented. The main issues in the theory of solar ponds are discussed. Among these are the interfacial-boundary-layer model, models for interface motion and pond performance, heat extraction, and ground heat loss. The core of the research effort at Los Alamos was the development of a one-dimensional computer program to accurately predict dynamic performance of a solar pond. The computer model and the experiments that were designed and performed to validate it are described. The experiments include two laboratory tanks wherein temperature, salinity, and flow visualization data were obtained and a 232 m/sup 2/ outdoor solar pond. Results from preliminary validation show good agreement between the pond's predicted dynamic behavior and that which actually occurred in the experiments. More validation using data from full-sized solar ponds is needed. A new correlation for the ratio of interfacial salt-flux to heat-flux is proposed which agrees well with our data. Recommendations for future research are given.

  20. New Generation of Los Alamos Opacity Tables

    NASA Astrophysics Data System (ADS)

    Colgan, James; Kilcrease, D. P.; Magee, N. H.; Sherrill, M. E.; Abdallah, J.; Hakel, P.; Fontes, C. J.; Guzik, J. A.; Mussack, K. A.

    2016-05-01

    We present a new generation of Los Alamos OPLIB opacity tables that have been computed using the ATOMIC code. Our tables have been calculated for all 30 elements from hydrogen through zinc and are publicly available through our website. In this poster we discuss the details of the calculations that underpin the new opacity tables. We also show several recent applications of the use of our opacity tables to solar modeling and other astrophysical applications. In particular, we demonstrate that use of the new opacities improves the agreement between solar models and helioseismology, but does not fully resolve the long-standing `solar abundance' problem. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396.

  1. Status of Monte Carlo at Los Alamos

    SciTech Connect

    Thompson, W.L.; Cashwell, E.D.

    1980-01-01

    At Los Alamos the early work of Fermi, von Neumann, and Ulam has been developed and supplemented by many followers, notably Cashwell and Everett, and the main product today is the continuous-energy, general-purpose, generalized-geometry, time-dependent, coupled neutron-photon transport code called MCNP. The Los Alamos Monte Carlo research and development effort is concentrated in Group X-6. MCNP treats an arbitrary three-dimensional configuration of arbitrary materials in geometric cells bounded by first- and second-degree surfaces and some fourth-degree surfaces (elliptical tori). Monte Carlo has evolved into perhaps the main method for radiation transport calculations at Los Alamos. MCNP is used in every technical division at the Laboratory by over 130 users about 600 times a month accounting for nearly 200 hours of CDC-7600 time.

  2. Publications of Los Alamos Research, 1983

    SciTech Connect

    Sheridan, C.J.; McClary, W.J.; Rich, J.A.; Rodriguez, L.L.

    1984-10-01

    This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1983. Papers published in 1982 are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted - even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was published more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers released as non-Laboratory reports, journal articles, books, chapters of books, conference papers either published separately or as part of conference proceedings issued as books or reports, papers publishd in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.

  3. Publications of Los Alamos research 1980

    SciTech Connect

    Salazar, C.A.; Willis, J.K.

    1981-09-01

    This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1980. Papers published in 1980 are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted-even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was pubished more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers released as non-laboratory reports, journal articles, books, chapters of books, conference papers published either separately or as part of conference proceedings issued as books or reports, papers published in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.

  4. Experiences with Extra-Vehicular Activities in Response to Critical ISS Contingencies

    NASA Technical Reports Server (NTRS)

    Van Cise, E. A.; Kelly, B. J.; Radigan, J. P.; Cranmer, C. W.

    2016-01-01

    Contingency EVA preparation team structure, approach, goals, and the resources allocated to its work after the 2010 events. Finally, the authors will overview the implementation of these updates in addressing failures onboard the ISS in 2012, 2013, and 2014. The successful use of the updated approaches, and the application of the approaches to other spacewalks, will demonstrate the effectiveness of this additional work and make a case for putting significant time and resources into pre-failure planning and analysis for critical hardware items on human-tended spacecraft.

  5. Experiences with Extra-Vehicular Activities in Response to Critical ISS Contingencies

    NASA Technical Reports Server (NTRS)

    Van Cise, E. A.; Kelly, B. J.; Radigan, J. P.; Cranmer, C. W.

    2016-01-01

    EVA preparation team structure, approach, goals, and the resources allocated to its work after the 2010 events. Finally, the authors will overview the implementation of these updates in addressing failures onboard the ISS in 2012, 2013, and 2014. The successful use of the updated approaches, and the application of the approaches to other spacewalks, will demonstrate the effectiveness of this additional work and make a case for putting significant time and resources into pre-failure planning and analysis for critical hardware items on human-tended spacecraft.

  6. Recent UCN source developments at Los Alamos

    SciTech Connect

    Seestrom, S.J.; Anaya, J.M.; Bowles, T.J.

    1998-12-01

    The most intense sources of ultra cold neutrons (UCN) have bee built at reactors where the high average thermal neutron flux can overcome the low UCN production rate to achieve usable densities of UCN. At spallation neutron sources the average flux available is much lower than at a reactor, though the peak flux can be comparable or higher. The authors have built a UCN source that attempts to take advantage of the high peak flux available at the short pulse spallation neutron source at the Los Alamos Neutron Science Center (LANSCE) to generate a useful number of UCN. In the source UCN are produced by Doppler-shifted Bragg scattering of neutrons to convert 400-m/s neutrons down into the UCN regime. This source was initially tested in 1996 and various improvements were made based on the results of the 1996 running. These improvements were implemented and tested in 1997. In sections 2 and 3 they discuss the improvements that have been made and the resulting source performance. Recently an even more interesting concept was put forward by Serebrov et al. This involves combining a solid Deuterium UCN source, previously studied by Serebrov et al., with a pulsed spallation source to achieve world record UCN densities. They have initiated a program of calculations and measurements aimed at verifying the solid Deuterium UCN source concept. The approach has been to develop an analytical capability, combine with Monte Carlo calculations of neutron production, and perform benchmark experiments to verify the validity of the calculations. Based on the calculations and measurements they plan to test a modified version of the Serebrov UCN factory. They estimate that they could produce over 1,000 UCN/cc in a 15 liter volume, using 1 {micro}amp of 800 MeV protons for two seconds every 500 seconds. They will discuss the result UCN production measurements in section 4.

  7. Beam funneling studies at Los Alamos

    SciTech Connect

    Stovall, J.E.; Guy, F.W.; Stokes, R.H.; Wangler, T.P.

    1988-01-01

    Funneling two ion beams by interlacing their bunches can reduce the cost and complexity of systems producing intense beams. Applications of funneling could include accelerators for heavy ion inertial fusion, electronuclear breeding, and fusion materials irradiation. Funneling in an RFQ-like structure is an elegant solution at low energy where electric fields are needed to provide strong focusing. Discrete-element funnels, with separate focusing elements, bending magnets, rebunchers and if deflectors, are more flexible. At sufficiently high energies, magnetic-quadrupole lenses can provide strong focusing in a discrete-element funnel. Such a funnel has been designed as a preliminary example of a second funnel in the HIBALL-II accelerator system. In a simulation, two Bi/sup +1/ (mass = 209 amu) beams at 0.5 MeV/A, 20 MHz, 40-mA, separated by 55 cm and angled at +-6/degree/ were combined into a single 80-mA beam at 40 MHz. Emittance growth was calculated, by a modified version of the PIC (particle-in-cell) code PARMILA, to be about 1%. Funnel design experience at Los Alamos has evolved rules-of-thumb that reduce emittance growth. Some of these are to maintain focusing periodicity and strength in both transverse and longitudinal directions; use strong focusing so that the bunch will be small; minimize angles of bend and rf deflection; adjust longitudinal focusing to produce a short bunch at the rf deflector; and design rf deflectors for a uniform electrical field. 4 refs., 3 figs., 2 tabs.

  8. SEDs at Los Alamos: A Personal Memoir

    NASA Astrophysics Data System (ADS)

    Bederson, Benjamin

    2001-03-01

    I have written this personal memoir approximately 55 years after the events I describe. It is based almost exclusively on memory, since apart from the diary I kept while on Tinian, I have few documents concerning it. It covers my service in the U.S. Army's Special Engineering Detachment (SED) in Oak Ridge and Los Alamos in 1944-45, on Tinian island, the launching pad for the bombing raids on Japan, in the summer and fall of 1945, and my return to Los Alamos until my discharge in January 1946.

  9. Upper Los Alamos canyon fact sheet

    SciTech Connect

    Berger, Jeffrey H

    2007-01-01

    Los Alamos National Laboratory is planning to make environmental assessments in portions of Upper Los Alamos Canyon. Upper Los Alamos Canyon is one of the areas included in the 2005 Consent Order agreed to by Los Alamos National Laboratory, the National Nuclear Security Administration, and the New Mexico Environment Department. As such, it must be evaluated for potential contamination. The area is located within and south of the Los Alamos townsite in Technical Areas 00, 01, 03, 32, 41, 43, and 61 of Los Alamos National Laboratory and includes a total of 115 solid waste management units and areas of concern. This area was home to some of the earliest operations at Los Alamos, dating from the 1940s. Of the 115 solid-waste management units and areas of concern, 54 have been addressed previously. The remaining 61 are the focus of this project. These include septic tanks and outfalls, sanitary and industrial waste lines, storm drains, soil contamination areas, landfill and surface disposal areas, transformer sites, and incinerators. The Consent Order requires the Laboratory to evaluate historical work sites for the potential presence of residual contamination. It also requires the Laboratory to identify and implement corrective actions should contamination be found. The Laboratory began performing these types of activities in the 1990s. The Upper Los Alamos Canyon project entails: (1) collecting soil and rock samples using the most efficient and least-invasive methods practicable; (2) defining the nature and extent of any residual contamination associated with each solid waste management unit or area of concern; and (3) gathering additional data if needed to evaluate potential remedial alternatives. A variety of methods, including studies of engineering drawings, nonintrusive geophysical surveys, and trenching, may be used to identify the final sampling locations. The field team then determines which collection method to use at each location, based on such site

  10. Plutonium 238 facilities at Los Alamos

    NASA Astrophysics Data System (ADS)

    Rinehart, Gary H.

    1991-01-01

    Plutonium 238 operations at Los Alamos are performed at the Plutonium Facility (TA-55), the Chemistry and Metallurgy Research (CMR) Building, and the Radioisotope Fuels Impact Test Facility. The plutonium 238 facilities at Los Alamos support a wide variety of heat source activities including development of new fuel forms and containment materials, research on the high temperature properties of containment materials, investigation of the high temperature compatibility of fuels with potential container materials, processing plutonium 238 fuel forms, manufacture of heat sources under quality assurance surveillance, and performing safety testing on heat sources and radioisotope thermoelectric generators.

  11. Plutonium-238 facilities at Los Alamos

    NASA Astrophysics Data System (ADS)

    Rinehart, Gary H.

    Plutonium-238 operations at Los Alamos are performed at the Plutonium Facility (TA-55), the Chemistry and Metallurgy Research (CMR) Building, and the Radioisotope Fuels Impact Test Facility. The plutonium-238 facilities at Los Alamos support a wide variety of heat source activities including development of new fuel forms and containment materials, research on the high temperature properties of containment materials, investigation of the high temperature compatibility of fuels with potential container materials, processing plutonium-238 fuel forms, manufacture of heat sources under quality assurance surveillance, and performing safety testing on heat sources and radioisotope thermoelectric generators.

  12. UCN Transport for the UCNA Experiment

    NASA Astrophysics Data System (ADS)

    Vorndick, Brittney

    2014-03-01

    The UCNA Experiment at Los Alamos National Laboratory utilizes polarized ultracold neutrons (UCN) from a spallation-driven solid deuterium UCN converter. The polarized UCN are bottled in a 1 Tesla 2 × 2 π magnetic spectrometer to measure the β asymmetry parameter A. In order to store the UCN, the materials used for transport and storage of UCN is critical. Diamond-like carbon (DLC) coatings are used in order to minimize depolarization and loss. We discuss the fabrication, characterization, and modeling of DLC-coated guides used in the experiment.

  13. "A Moving Target": A Critical Race Analysis of Latina/o Faculty Experiences, Perspectives, and Reflections on the Tenure and Promotion Process

    ERIC Educational Resources Information Center

    Urrieta, Luis, Jr.; Méndez, Lina; Rodríguez, Esmeralda

    2015-01-01

    This article examines how Latina/o professors perceive, experience, and reflect on the tenure and promotion process. Findings for this longitudinal study are drawn from a purposive sample of nine female and seven male, Latina/o tenure-track faculty participants. Using a Critical Race Theory, Latino Critical (LatCrit) Race Theory, and Chicana…

  14. Quantifying critical conditions for seaward expansion of tidal marshes: A transplantation experiment

    NASA Astrophysics Data System (ADS)

    Silinski, Alexandra; van Belzen, Jim; Fransen, Erik; Bouma, Tjeerd J.; Troch, Peter; Meire, Patrick; Temmerman, Stijn

    2016-02-01

    The alternative stable states theory is increasingly applied to tidal marsh shorelines, where the two opposing stable states - a dense vegetated state on the one hand and a bare tidal flat on the other hand - can coexist in time but differ in space. The shift from the bare to vegetated state by the establishment of individual plants (seedlings, rhizome-grown shoots) on the bare tidal flat is known to be triggered by the occurrence of windows of opportunity. These are periods when species- and life stage-dependent thresholds, such as sediment dynamics or wave impact, are not exceeded. One controlling environmental parameter in intertidal wetlands is elevation as many important stressors for plants - such as hydroperiod, sediment dynamics and wave properties (wave period and wave height) - are typically correlated to it. Disentangling the respective impact of these correlated stressors remains challenging. In this paper, we present the results of a transplantation experiment where the establishment of three different life stages (seedlings, rhizome-grown shoots and patches) of the brackish pioneer Scirpus maritimus was tested over an elevation gradient at two locations of contrasting wave exposure. This gradient reached from the bare tidal flat into the marsh and covered an elevation range at which continuous S. maritimus-dominated pioneer marsh is known to occur. We found that erosion stress influences seedling survival on tidal flats while drought stress seems to limit long-term establishment of individual shoots and seedlings in the marsh. Furthermore, survival of transplants was more successful on the tidal flat of the sheltered site compared to the tidal flat of the exposed site whereas survival time within the marsh did not differ between sites. This highlights the attenuation of waves and currents in exposed marshes. However, no long-term establishment occurred on the tidal flat, emphasizing the importance of clonal integration for tidal flat colonization.

  15. Half of the family members of critically ill patients experience excessive daytime sleepiness

    PubMed Central

    Verceles, Avelino C.; Corwin, Douglas S.; Afshar, Majid; Friedman, Eliot B.; McCurdy, Michael T.; Shanholtz, Carl; Oakjones, Karen; Zubrow, Marc T.; Titus, Jennifer; Netzer, Giora

    2015-01-01

    Background Sleepiness and fatigue are commonly reported by family members of intensive care unit (ICU) patients. Sleep deprivation may result in cognitive deficits. Sleep deprivation and cognitive blunting have not been quantitatively assessed in this population. We sought to determine the proportion of family members of ICU patients that experience excessive daytime sleepiness, sleep-associated functional impairment, and cognitive blunting. Methods Multicenter, cross-sectional survey of family members of patients admitted to ICUs at the University of Maryland Medical Center, Johns Hopkins University Hospital, and Christiana Hospital. Family members of ICU patients were evaluated using the Epworth Sleepiness Scale, a validated survey assessing sleepiness in everyday situations (normal, less than 10); the Functional Outcomes of Sleep Questionnaire-10 (FOSQ-10), a questionnaire quantifying the impact of sleepiness on daily activities (normal, at least 17.9); and psychomotor vigilance testing, a test of cognitive function, in relation to sleep deprivation (normal mean reaction time less than 500 ms). Results A total of 225 family members were assessed. Of these, 50.2 % (113/225) had Epworth scores consistent with excessive daytime sleepiness. Those with sleepiness experienced greater impairment in performing daily activities by FOSQ-10 (15.6 ± 3.0 vs 17.4 ± 2.2, p < 0.001). Cognitive blunting was found in 13.3 % (30/225) of family members and 15.1 % (14/93) of surrogate decision-makers. Similar rates of cognitive blunting as reported by mean reaction time of at least 500 ms were found among family members whether or not they reported sleepiness (15.0 % (17/113) vs. 11.6 % (13/112), p = 0.45). Conclusions Half of the family members of ICU patients suffer from excessive daytime sleepiness. This sleepiness is associated with functional impairment, but not cognitive blunting. PMID:24898893

  16. Los Alamos contribution to target diagnostics on the National Ignition Facility

    SciTech Connect

    Mack, J.M.; Baker, D.A.; Caldwell, S.E.

    1994-07-01

    The National Ignition Facility (NIF) will have a large suite of sophisticated target diagnostics. This will allow thoroughly diagnosed experiments to be performed both at the ignition and pre-ignition levels. As part of the national effort Los Alamos National Laboratory will design, construct and implement a number of diagnostics for the NIF. This paper describes Los Alamos contributions to the ``phase I diagnostics.`` Phase I represents the most fundamental and basic measurement systems that will form the core for most work on the NIF. The Los Alamos effort falls into four categories: moderate to hard X-ray (time resolved imaging neutron spectroscopy- primarily with neutron time of flight devices; burn diagnostics utilizing gamma ray measurements; testing measurement concepts on the TRIDENT laser system at Los Alamos. Because of the high blast, debris and radiation environment, the design of high resolution X-ray imaging systems present significant challenges. Systems with close target proximity require special protection and methods for such protection is described. The system design specifications based on expected target performance parameters is also described. Diagnosis of nuclear yield and burn will be crucial to the NIF operation. Nuclear reaction diagnosis utilizing both neutron and gamma ray detection is discussed. The Los Alamos TRIDENT laser system will be used extensively for the development of new measurement concepts and diagnostic instrumentation. Some its potential roles in the development of diagnostics for NIF are given.

  17. RCRA facility investigation for the townsite of Los Alamos, New Mexico

    SciTech Connect

    Dorries, A.M.; Conrad, R.C.; Nonno, L.M.

    1992-01-01

    During World War II, Los Alamos, New Mexico was established as an ideal location for the secrecy and safety needed for the research and development required to design a nuclear fission bomb. Experiments carried out in the 1940s generated both radioactive and hazardous waste constituents on what is presently part of the Los Alamos townsite. Under the RCRA permit issued to Los alamos national Laboratory in 1990, the Laboratory is scheduled for investigation of its solid waste management units (SWMUs). The existing information on levels of radioactivity on the townsite is principally data from soil samples taken during the last site decontamination in 1976, little information on the presence of hazardous constituents exists today. This paper addresses pathway analysis and a preliminary risk assessment for current residents of the Los Alamos townsite. The estimated dose levels, in mrem per year, show that the previously decontaminated SWMU areas on the Los Alamos townsite will not contribute a radiation dose of any concern to the current residents.

  18. RCRA facility investigation for the townsite of Los Alamos, New Mexico

    SciTech Connect

    Dorries, A.M.; Conrad, R.C.; Nonno, L.M.

    1992-02-01

    During World War II, Los Alamos, New Mexico was established as an ideal location for the secrecy and safety needed for the research and development required to design a nuclear fission bomb. Experiments carried out in the 1940s generated both radioactive and hazardous waste constituents on what is presently part of the Los Alamos townsite. Under the RCRA permit issued to Los alamos national Laboratory in 1990, the Laboratory is scheduled for investigation of its solid waste management units (SWMUs). The existing information on levels of radioactivity on the townsite is principally data from soil samples taken during the last site decontamination in 1976, little information on the presence of hazardous constituents exists today. This paper addresses pathway analysis and a preliminary risk assessment for current residents of the Los Alamos townsite. The estimated dose levels, in mrem per year, show that the previously decontaminated SWMU areas on the Los Alamos townsite will not contribute a radiation dose of any concern to the current residents.

  19. Experience-dependent emergence of beta and gamma band oscillations in the primary visual cortex during the critical period

    PubMed Central

    Chen, Guang; Rasch, Malte J.; Wang, Ran; Zhang, Xiao-hui

    2015-01-01

    Neural oscillatory activities have been shown to play important roles in neural information processing and the shaping of circuit connections during development. However, it remains unknown whether and how specific neural oscillations emerge during a postnatal critical period (CP), in which neuronal connections are most substantially modified by neural activity and experience. By recording local field potentials (LFPs) and single unit activity in developing primary visual cortex (V1) of head-fixed awake mice, we here demonstrate an emergence of characteristic oscillatory activities during the CP. From the pre-CP to CP, the peak frequency of spontaneous fast oscillatory activities shifts from the beta band (15–35 Hz) to the gamma band (40–70 Hz), accompanied by a decrease of cross-frequency coupling (CFC) and broadband spike-field coherence (SFC). Moreover, visual stimulation induced a large increase of beta-band activity but a reduction of gamma-band activity specifically from the CP onwards. Dark rearing of animals from the birth delayed this emergence of oscillatory activities during the CP, suggesting its dependence on early visual experience. These findings suggest that the characteristic neuronal oscillatory activities emerged specifically during the CP may represent as neural activity trait markers for the experience-dependent maturation of developing visual cortical circuits. PMID:26648548

  20. Design of experiments reveals critical parameters for pilot-scale freeze-and-thaw processing of L-lactic dehydrogenase.

    PubMed

    Roessl, Ulrich; Humi, Sebastian; Leitgeb, Stefan; Nidetzky, Bernd

    2015-09-01

    Freezing constitutes an important unit operation of biotechnological protein production. Effects of freeze-and-thaw (F/T) process parameters on stability and other quality attributes of the protein product are usually not well understood. Here a design of experiments (DoE) approach was used to characterize the F/T behavior of L-lactic dehydrogenase (LDH) in a 700-mL pilot-scale freeze container equipped with internal temperature and pH probes. In 24-hour experiments, target temperature between -10 and -38°C most strongly affected LDH stability whereby enzyme activity was retained best at the highest temperature of -10°C. Cooling profile and liquid fill volume also had significant effects on LDH stability and affected the protein aggregation significantly. Parameters of the thawing phase had a comparably small effect on LDH stability. Experiments in which the standard sodium phosphate buffer was exchanged by Tris-HCl and the non-ionic surfactant Tween 80 was added to the protein solution showed that pH shift during freezing and protein surface exposure were the main factors responsible for LDH instability at the lower freeze temperatures. Collectively, evidence is presented that supports the use of DoE-based systematic analysis at pilot scale in the identification of F/T process parameters critical for protein stability and in the development of suitable process control strategies. PMID:25820483

  1. Critical experiments with mixed plutonium-uranium nitrate solutions having Pu:(Pu + U) ratios greater than 0.5

    SciTech Connect

    Primm, R.T. III; Lloyd, R.C.; Clayton, E.D.

    1986-04-01

    A series of critical experiments was conducted with mixed plutonium-uranium nitrate solutions having Pu:(Pu+U) ratios >0.5. Three geometries and four conditions of reflection were examined. The plutonium concentrations ranged from 170 to 350 g/L. The value of k-effective for each experiment was calculated using the KENO-IV code and 27-group cross sections derived from the Evaluated Nuclear Data File B--version IV (ENDF/B-IV). The mean value for the set of 26 experiments was 1.003, with a minimum value of 0.987 and a maximum of 1.022. The spread in the distribution of calculated k-effectives is believed to be the result of uncertainties in analytical chemistry measurements. No correlation between condition of reflection and calculated k-effective was found. An allowable multiplication factor to be used in the evaluation of reprocessing equipment at conditions that have been investigated was calculated to be 0.945.

  2. Los Alamos Controlled Air Incinerator for radioactive waste. Volume I. Rationale, process, equipment, performance, and recommendations

    SciTech Connect

    Neuls, A.S.; Draper, W.E.; Koenig, R.A.; Newmyer, J.M.; Warner, C.L.

    1982-08-01

    This two-volume report is a detailed design and operating documentation of the Los Alamos National Laboratory Controlled Air Incinerator (CAI) and is an aid to technology transfer to other Department of Energy contractor sites and the commercial sector. Volume I describes the CAI process, equipment, and performance, and it recommends modifications based on Los Alamos experience. It provides the necessary information for conceptual design and feasibility studies. Volume II provides descriptive engineering information such as drawing, specifications, calculations, and costs. It aids duplication of the process at other facilities.

  3. Los Alamos Controlled Air Incinerator for radioactive waste. Volume II. Engineering design reference manual

    SciTech Connect

    Koenig, R.A.; Draper, W.E.; Newmyer, J.M.; Warner, C.L.

    1982-10-01

    This two-volume report is a detailed design and operating documentation of the Los Alamos National Laboratory Controlled Air Incinerator (CAI) and is an aid to technology transfer to other Department of Energy contractor sites and the commercial sector. Volume I describes the CAI process, equipment, and performance, and it recommends modifications based on Los Alamos experience. It provides the necessary information for conceptual design and feasibility studies. Volume II provides descriptive engineering information such as drawings, specifications, calculations, and costs. It aids duplication of the process at other facilities.

  4. Proceedings of the Los Alamos neutrino workshop

    SciTech Connect

    Boehm, F.; Stephenson, G.J. Jr.

    1982-08-01

    A workshop on neutrino physics was held at Los Alamos from June 8 to 12, 1981. The material presented has been provided in part by the organizers, in part by the chairmen of the working sessions. Closing date for contributions was October 1981.

  5. Induction inserts at the Los Alamos PSR

    SciTech Connect

    King-Yuen Ng

    2002-09-30

    Ferrite-loaded induction tuners installed in the Los Alamos Proton Storage Ring have been successful in compensating space-charge effects. However, the resistive part of the ferrite introduces unacceptable microwave instability and severe bunch lengthening. An effective cure was found by heating the ferrite cores up to {approx} 130 C. An understanding of the instability and cure is presented.

  6. Los Alamos waste drum shufflers users manual

    SciTech Connect

    Rinard, P.M.; Adams, E.L.; Painter, J.

    1993-08-24

    This user manual describes the Los Alamos waste drum shufflers. The primary purpose of the instruments is to assay the mass of {sup 235}U (or other fissile materials) in drums of assorted waste. It can perform passive assays for isotopes that spontaneously emit neutrons or active assays using the shuffler technique as described on this manual.

  7. INTEGRAL BENCHMARKS AVAILABLE THROUGH THE INTERNATIONAL REACTOR PHYSICS EXPERIMENT EVALUATION PROJECT AND THE INTERNATIONAL CRITICALITY SAFETY BENCHMARK EVALUATION PROJECT

    SciTech Connect

    J. Blair Briggs; Lori Scott; Enrico Sartori; Yolanda Rugama

    2008-09-01

    Interest in high-quality integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties accelerate to meet the demands of next generation reactor and advanced fuel cycle concepts. The International Reactor Physics Experiment Evaluation Project (IRPhEP) and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) continue to expand their efforts and broaden their scope to identify, evaluate, and provide integral benchmark data for method and data validation. Benchmark model specifications provided by these two projects are used heavily by the international reactor physics, nuclear data, and criticality safety communities. Thus far, 14 countries have contributed to the IRPhEP, and 20 have contributed to the ICSBEP. The status of the IRPhEP and ICSBEP is discussed in this paper, and the future of the two projects is outlined and discussed. Selected benchmarks that have been added to the IRPhEP and ICSBEP handbooks since PHYSOR’06 are highlighted, and the future of the two projects is discussed.

  8. Los Alamos Fires From Landsat 7

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On May 9, 2000, the Landsat 7 satellite acquired an image of the area around Los Alamos, New Mexico. The Landsat 7 satellite acquired this image from 427 miles in space through its sensor called the Enhanced Thematic Mapper Plus (ETM+). Evident within the imagery is a view of the ongoing Cerro Grande fire near the town of Los Alamos and the Los Alamos National Laboratory. Combining the high-resolution (30 meters per pixel in this scene) imaging capacity of ETM+ with its multi-spectral capabilities allows scientists to penetrate the smoke plume and see the structure of the fire on the surface. Notice the high-level of detail in the infrared image (bottom), in which burn scars are clearly distinguished from the hotter smoldering and flaming parts of the fire. Within this image pair several features are clearly visible, including the Cerro Grande fire and smoke plume, the town of Los Alamos, the Los Alamos National Laboratory and associated property, and Cerro Grande peak. Combining ETM+ channels 7, 4, and 2 (one visible and two infrared channels) results in a false color image where vegetation appears as bright to dark green (bottom image). Forested areas are generally dark green while herbaceous vegetation is light green. Rangeland or more open areas appear pink to light purple. Areas with extensive pavement or urban development appear light blue or white to purple. Less densely-developed residential areas appear light green and golf courses are very bright green. The areas recently burned appear black. Dark red to bright red patches, or linear features within the burned area, are the hottest and possibly actively burning areas of the fire. The fire is spreading downslope and the front of the fire is readily detectable about 2 kilometers to the west and south of Los Alamos. Combining ETM+ channels 3, 2, and 1 provides a true-color image of the greater Los Alamos region (top image). Vegetation is generally dark to medium green. Forested areas are very dark green

  9. Validation of multigroup neutron cross sections and calculational methods for the advanced neutron source against the FOEHN critical experiments measurements

    SciTech Connect

    Smith, L.A.; Gallmeier, F.X.; Gehin, J.C.

    1995-05-01

    The FOEHN critical experiment was analyzed to validate the use of multigroup cross sections and Oak Ridge National Laboratory neutronics computer codes in the design of the Advanced Neutron Source. The ANSL-V 99-group master cross section library was used for all the calculations. Three different critical configurations were evaluated using the multigroup KENO Monte Carlo transport code, the multigroup DORT discrete ordinates transport code, and the multigroup diffusion theory code VENTURE. The simple configuration consists of only the fuel and control elements with the heavy water reflector. The intermediate configuration includes boron endplates at the upper and lower edges of the fuel element. The complex configuration includes both the boron endplates and components in the reflector. Cross sections were processed using modules from the AMPX system. Both 99-group and 20-group cross sections were created and used in two-dimensional models of the FOEHN experiment. KENO calculations were performed using both 99-group and 20-group cross sections. The DORT and VENTURE calculations were performed using 20-group cross sections. Because the simple and intermediate configurations are azimuthally symmetric, these configurations can be explicitly modeled in R-Z geometry. Since the reflector components cannot be modeled explicitly using the current versions of these codes, three reflector component homogenization schemes were developed and evaluated for the complex configuration. Power density distributions were calculated with KENO using 99-group cross sections and with DORT and VENTURE using 20-group cross sections. The average differences between the measured values and the values calculated with the different computer codes range from 2.45 to 5.74%. The maximum differences between the measured and calculated thermal flux values for the simple and intermediate configurations are {approx} 13%, while the average differences are < 8%.

  10. Is a good death possible in Australian critical and acute settings?: physician experiences with end-of-life care

    PubMed Central

    2014-01-01

    Background In Australia approximately 70% of all deaths are institutionalised but over 15% of deaths occur in intensive care settings where the ability to provide a “good death” is particularly inhibited. Yet, there is a growing trend for death and dying to be managed in the ICU and physicians are increasingly challenged to meet the new expectations of their specialty. This study examined the unexplored interface between specialised Australian palliative and intensive care and the factors influencing a physician’s ability to manage deaths well. Method A qualitative investigation was focused on palliative and critical/acute settings. A thematic analysis was conducted on semi-structured in-depth interviews with 13 specialist physicians. Attention was given to eliciting meanings and experiences in Australian end-of-life care. Results Physicians negotiated multiple influences when managing dying patients and their families in the ICU. The way they understood and experienced end-of-life care practices was affected by cultural, institutional and professional considerations, and personal values and beliefs. Interpersonal and intrapsychic aspects highlighted the emotional and psychological relationship physicians have with patients and others. Many physicians were also unaware of what their cross-disciplinary colleagues could or could not do; poor professional recognition and collaboration, and ineffective care goal transition impaired their ability to assist good deaths. Experience was subject to the efficacy of physicians in negotiating complex bedside dynamics. Conclusions Regardless of specialty, all physicians identified the problematic nature of providing expert palliation in critical and acute settings. Strategies for integrating specialised palliative and intensive care were offered with corresponding directions for future research and clinical development. PMID:25147481

  11. Los Alamos Guns Take Aim at Material's Mysteries

    ScienceCinema

    Byers, Mark; Moore, David; Dimarino, Steve

    2014-05-30

    Los Alamos National Laboratory scientists and technicians conduct thousands of experiments a year, delving into the fundamental nature of everything from supernovas to subatomic particles. One set of instruments used to better understand the fundamental nature of various materials are 10 scientific gun systems that fire various projectiles at high-tech targets to create enormous velocities, pressures, and temperatures - and using laser, x-ray, and other diagnostics - explore the very nature of metals and other materials. The hundreds of gun-based experiments conducted every year at the Laboratory require a highly-skilled staff of scientists and technicians, and has given rise to a special organization called the "gun working group" to foster open communications, cooperation, problem-solving, and a healthy safety culture.

  12. Los Alamos Guns Take Aim at Material's Mysteries

    SciTech Connect

    Byers, Mark; Moore, David; Dimarino, Steve

    2014-04-14

    Los Alamos National Laboratory scientists and technicians conduct thousands of experiments a year, delving into the fundamental nature of everything from supernovas to subatomic particles. One set of instruments used to better understand the fundamental nature of various materials are 10 scientific gun systems that fire various projectiles at high-tech targets to create enormous velocities, pressures, and temperatures - and using laser, x-ray, and other diagnostics - explore the very nature of metals and other materials. The hundreds of gun-based experiments conducted every year at the Laboratory require a highly-skilled staff of scientists and technicians, and has given rise to a special organization called the "gun working group" to foster open communications, cooperation, problem-solving, and a healthy safety culture.

  13. Los Alamos Center for Computer Security formal computer security model

    SciTech Connect

    Dreicer, J.S.; Hunteman, W.J.; Markin, J.T.

    1989-01-01

    This paper provides a brief presentation of the formal computer security model currently being developed at the Los Alamos Department of Energy (DOE) Center for Computer Security (CCS). The need to test and verify DOE computer security policy implementation first motivated this effort. The actual analytical model was a result of the integration of current research in computer security and previous modeling and research experiences. The model is being developed to define a generic view of the computer and network security domains, to provide a theoretical basis for the design of a security model, and to address the limitations of present formal mathematical models for computer security. The fundamental objective of computer security is to prevent the unauthorized and unaccountable access to a system. The inherent vulnerabilities of computer systems result in various threats from unauthorized access. The foundation of the Los Alamos DOE CCS model is a series of functionally dependent probability equations, relations, and expressions. The model is undergoing continued discrimination and evolution. We expect to apply the model to the discipline of the Bell and LaPadula abstract sets of objects and subjects. 6 refs.

  14. Seismic vulnerability study Los Alamos Meson Physics Facility (LAMPF)

    SciTech Connect

    Salmon, M.; Goen, L.K.

    1995-12-01

    The Los Alamos Meson Physics Facility (LAMPF), located at TA-53 of Los Alamos National Laboratory (LANL), features an 800 MeV proton accelerator used for nuclear physics and materials science research. As part of the implementation of DOE Order 5480.25 and in preparation for DOE Order 5480.28, a seismic vulnerability study of the structures, systems, and components (SSCs) supporting the beam line from the accelerator building through to the ends of die various beam stops at LAMPF has been performed. The study was accomplished using the SQUG GIP methodology to assess the capability of the various SSCs to resist an evaluation basis earthquake. The evaluation basis earthquake was selected from site specific seismic hazard studies. The goals for the study were as follows: (1) identify SSCs which are vulnerable to seismic loads; and (2) ensure that those SSCs screened during die evaluation met the performance goals required for DOE Order 5480.28. The first goal was obtained by applying the SQUG GIP methodology to those SSCS represented in the experience data base. For those SSCs not represented in the data base, information was gathered and a significant amount of engineering judgment applied to determine whether to screen the SSC or to classify it as an outlier. To assure the performance goals required by DOE Order 5480.28 are met, modifications to the SQUG GIP methodology proposed by Salmon and Kennedy were used. The results of this study ire presented in this paper.

  15. The Los Alamos suite of relativistic atomic physics codes

    SciTech Connect

    Fontes, C. J.; Zhang, H. L.; Jr, J. Abdallah; Clark, R. E. H.; Kilcrease, D. P.; Colgan, J.; Cunningham, R. T.; Hakel, P.; Magee, N. H.; Sherrill, M. E.

    2015-05-28

    The Los Alamos SuitE of Relativistic (LASER) atomic physics codes is a robust, mature platform that has been used to model highly charged ions in a variety of ways. The suite includes capabilities for calculating data related to fundamental atomic structure, as well as the processes of photoexcitation, electron-impact excitation and ionization, photoionization and autoionization within a consistent framework. These data can be of a basic nature, such as cross sections and collision strengths, which are useful in making predictions that can be compared with experiments to test fundamental theories of highly charged ions, such as quantum electrodynamics. The suite can also be used to generate detailed models of energy levels and rate coefficients, and to apply them in the collisional-radiative modeling of plasmas over a wide range of conditions. Such modeling is useful, for example, in the interpretation of spectra generated by a variety of plasmas. In this work, we provide a brief overview of the capabilities within the Los Alamos relativistic suite along with some examples of its application to the modeling of highly charged ions.

  16. The Los Alamos suite of relativistic atomic physics codes

    DOE PAGESBeta

    Fontes, C. J.; Zhang, H. L.; Jr, J. Abdallah; Clark, R. E. H.; Kilcrease, D. P.; Colgan, J.; Cunningham, R. T.; Hakel, P.; Magee, N. H.; Sherrill, M. E.

    2015-05-28

    The Los Alamos SuitE of Relativistic (LASER) atomic physics codes is a robust, mature platform that has been used to model highly charged ions in a variety of ways. The suite includes capabilities for calculating data related to fundamental atomic structure, as well as the processes of photoexcitation, electron-impact excitation and ionization, photoionization and autoionization within a consistent framework. These data can be of a basic nature, such as cross sections and collision strengths, which are useful in making predictions that can be compared with experiments to test fundamental theories of highly charged ions, such as quantum electrodynamics. The suitemore » can also be used to generate detailed models of energy levels and rate coefficients, and to apply them in the collisional-radiative modeling of plasmas over a wide range of conditions. Such modeling is useful, for example, in the interpretation of spectra generated by a variety of plasmas. In this work, we provide a brief overview of the capabilities within the Los Alamos relativistic suite along with some examples of its application to the modeling of highly charged ions.« less

  17. Hydrologic transport of depleted uranium associated with open air dynamic range testing at Los Alamos National Laboratory, New Mexico, and Eglin Air Force Base, Florida

    SciTech Connect

    Becker, N.M.; Vanta, E.B.

    1995-05-01

    Hydrologic investigations on depleted uranium fate and transport associated with dynamic testing activities were instituted in the 1980`s at Los Alamos National Laboratory and Eglin Air Force Base. At Los Alamos, extensive field watershed investigations of soil, sediment, and especially runoff water were conducted. Eglin conducted field investigations and runoff studies similar to those at Los Alamos at former and active test ranges. Laboratory experiments complemented the field investigations at both installations. Mass balance calculations were performed to quantify the mass of expended uranium which had transported away from firing sites. At Los Alamos, it is estimated that more than 90 percent of the uranium still remains in close proximity to firing sites, which has been corroborated by independent calculations. At Eglin, we estimate that 90 to 95 percent of the uranium remains at test ranges. These data demonstrate that uranium moves slowly via surface water, in both semi-arid (Los Alamos) and humid (Eglin) environments.

  18. Los Alamos National Security, LLC Request for Information from industrial entities that desire to commercialize Laboratory-developed Extremely Low Resource Optical Identifier (ELROI) tech

    SciTech Connect

    Erickson, Michael Charles

    2015-11-10

    Los Alamos National Security, LLC (LANS) is the manager and operator of the Los Alamos National Laboratory for the U.S. Department of Energy National Nuclear Security Administration under contract DE-AC52-06NA25396. LANS is a mission-centric Federally Funded Research and Development Center focused on solving the most critical national security challenges through science and engineering for both government and private customers.

  19. Evaluation of the concrete shield compositions from the 2010 criticality accident alarm system benchmark experiments at the CEA Valduc SILENE facility

    SciTech Connect

    Miller, Thomas Martin; Celik, Cihangir; Dunn, Michael E; Wagner, John C; McMahan, Kimberly L; Authier, Nicolas; Jacquet, Xavier; Rousseau, Guillaume; Wolff, Herve; Savanier, Laurence; Baclet, Nathalie; Lee, Yi-kang; Trama, Jean-Christophe; Masse, Veronique; Gagnier, Emmanuel; Naury, Sylvie; Blanc-Tranchant, Patrick; Hunter, Richard; Kim, Soon; Dulik, George Michael; Reynolds, Kevin H.

    2015-01-01

    In October 2010, a series of benchmark experiments were conducted at the French Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA) Valduc SILENE facility. These experiments were a joint effort between the United States Department of Energy Nuclear Criticality Safety Program and the CEA. The purpose of these experiments was to create three benchmarks for the verification and validation of radiation transport codes and evaluated nuclear data used in the analysis of criticality accident alarm systems. This series of experiments consisted of three single-pulsed experiments with the SILENE reactor. For the first experiment, the reactor was bare (unshielded), whereas in the second and third experiments, it was shielded by lead and polyethylene, respectively. The polyethylene shield of the third experiment had a cadmium liner on its internal and external surfaces, which vertically was located near the fuel region of SILENE. During each experiment, several neutron activation foils and thermoluminescent dosimeters (TLDs) were placed around the reactor. Nearly half of the foils and TLDs had additional high-density magnetite concrete, high-density barite concrete, standard concrete, and/or BoroBond shields. CEA Saclay provided all the concrete, and the US Y-12 National Security Complex provided the BoroBond. Measurement data from the experiments were published at the 2011 International Conference on Nuclear Criticality (ICNC 2011) and the 2013 Nuclear Criticality Safety Division (NCSD 2013) topical meeting. Preliminary computational results for the first experiment were presented in the ICNC 2011 paper, which showed poor agreement between the computational results and the measured values of the foils shielded by concrete. Recently the hydrogen content, boron content, and density of these concrete shields were further investigated within the constraints of the previously available data. New computational results for the first experiment are now available that

  20. Manipulation of BDNF Signaling Modifies the Experience-Dependent Plasticity Induced by Pure Tone Exposure during the Critical Period in the Primary Auditory Cortex

    PubMed Central

    Anomal, Renata; de Villers-Sidani, Etienne; Merzenich, Michael M.; Panizzutti, Rogerio

    2013-01-01

    Sensory experience powerfully shapes cortical sensory representations during an early developmental “critical period” of plasticity. In the rat primary auditory cortex (A1), the experience-dependent plasticity is exemplified by significant, long-lasting distortions in frequency representation after mere exposure to repetitive frequencies during the second week of life. In the visual system, the normal unfolding of critical period plasticity is strongly dependent on the elaboration of brain-derived neurotrophic factor (BDNF), which promotes the establishment of inhibition. Here, we tested the hypothesis that BDNF signaling plays a role in the experience-dependent plasticity induced by pure tone exposure during the critical period in the primary auditory cortex. Elvax resin implants filled with either a blocking antibody against BDNF or the BDNF protein were placed on the A1 of rat pups throughout the critical period window. These pups were then exposed to 7 kHz pure tone for 7 consecutive days and their frequency representations were mapped. BDNF blockade completely prevented the shaping of cortical tuning by experience and resulted in poor overall frequency tuning in A1. By contrast, BDNF infusion on the developing A1 amplified the effect of 7 kHz tone exposure compared to control. These results indicate that BDNF signaling participates in the experience-dependent plasticity induced by pure tone exposure during the critical period in A1. PMID:23700463

  1. Nuclear criticality safety guide

    SciTech Connect

    Pruvost, N.L.; Paxton, H.C.

    1996-09-01

    This technical reference document cites information related to nuclear criticality safety principles, experience, and practice. The document also provides general guidance for criticality safety personnel and regulators.

  2. Effect of visual experience on tubulin synthesis during a critical period of visual cortex development in the hooded rat.

    PubMed

    Cronly-Dillon, J; Perry, G W

    1979-08-01

    1. In some species, restriction of visual experience in early life may affect normal functional development of visual cortical cells. The purpose of the present study was to determine if visual deprivation during post-natal development in the hooded rat also affects the production in brain cells of certain molecular components such as tubulin, that are needed for growth and maintenance of synapses and neurites. 2. Norwegian black hooded rats were reared under a variety of conditions of visual deprivation. At various stages of development the animals were killed and the rate of synthesis of tubulin in visual and motor cortex determined. Tritiated colchicine was used to assay tubulin and L-[14C]leucine injected into the brain ventricles 2 hr before death was used to measure rate of tubulin synthesis. 3. In rats reared in normal light there is a marked elevation in visual cortex tubulin synthesis that spans the period from eye-opening (13 days) until approximately 35 days. This elevation in tubulin synthesis is absent in animals reared in darkness from birth or deprived of pattern vision by eyelid suture. Also the effect of visual deprivation on tubulin synthesis was specifically confined to visual cortex and was not found for the motor cortex. Similarly, the incorporation of L-[14C]leucine into total protein in visual cortex was unaffected by dark rearing. Hence the stimulation of tubulin synthesis by visual experience in rat visual cortex is not attributable to a general non-specific stimulation of protein synthesis. 4. Rats that were dark-reared from birth and then exposed to a lighted environment for 24 hr during a certain critical period that extends from eye-opening (13 days) until approximately 35 days, displayed a significant increase in visual cortex tubulin rats that were brought into the light later than 35 days showed no significant increase in tubulin synthesis when compared with their continuously dark-rearer controls. 5. It is suggested that the number

  3. Amphibians and Reptiles of Los Alamos County

    SciTech Connect

    Teralene S. Foxx; Timothy K. Haarmann; David C. Keller

    1999-10-01

    Recent studies have shown that amphibians and reptiles are good indicators of environmental health. They live in terrestrial and aquatic environments and are often the first animals to be affected by environmental change. This publication provides baseline information about amphibians and reptiles that are present on the Pajarito Plateau. Ten years of data collection and observations by researchers at Los Alamos National Laboratory, the University of New Mexico, the New Mexico Department of Game and Fish, and hobbyists are represented.

  4. Los Alamos Novel Rocket Design Flight Tested

    ScienceCinema

    Tappan, Bryce

    2015-01-05

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  5. Los Alamos Novel Rocket Design Flight Tested

    SciTech Connect

    Tappan, Bryce

    2014-10-23

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  6. Los Alamos Team Demonstrates Bottle Scanner Technology

    SciTech Connect

    Espy, Michelle; Schultz, Larry

    2014-05-06

    Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

  7. The Los Alamos accelerator code group

    SciTech Connect

    Krawczyk, F.L.; Billen, J.H.; Ryne, R.D.; Takeda, Harunori; Young, L.M.

    1995-05-01

    The Los Alamos Accelerator Code Group (LAACG) is a national resource for members of the accelerator community who use and/or develop software for the design and analysis of particle accelerators, beam transport systems, light sources, storage rings, and components of these systems. Below the authors describe the LAACG`s activities in high performance computing, maintenance and enhancement of POISSON/SUPERFISH and related codes and the dissemination of information on the INTERNET.

  8. Los Alamos Team Demonstrates Bottle Scanner Technology

    ScienceCinema

    Espy, Michelle; Schultz, Larry

    2014-06-02

    Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

  9. Los Alamos National Laboratory Facility Review

    SciTech Connect

    Nelson, Ronald Owen

    2015-06-05

    This series of slides depicts the Los Alamos Neutron Science Center (LANSCE). The Center's 800-MeV linac produces H+ and H- beams as well as beams of moderated (cold to 1 MeV) and unmoderated (0.1 to 600 MeV) neutrons. Experimental facilities and their capabilities and characteristics are outlined. Among these are LENZ, SPIDER, and DANCE.

  10. Los Alamos synchronous orbit data set

    SciTech Connect

    Baker, D.N.; Higbie, P.R.; Belian, R.D.; Hones, E.W.; Klebesadel, R.W.

    1981-01-01

    Energetic electron (30-15000 keV) and proton 145 keV to 150 MeV) measurements made by Los Alamos National Laboratory sensors at geostationary orbit (6.6 R/sub E/) are summarized. The instrumentation employed and the satellite positions are described. The spacecraft have been variously located, but in their present configuration the Los Alamos satellites designated 1976-059, 1977-007, and 1979-053 are located, respectively, at approx. 70/sup 0/W, approx. 70/sup 0/E, and approx. 135/sup 0/W longitude. Several examples of the high temporal and full three-dimensional spatial measurement capabilities of these instruments are illustrated by examples from the published literature. Discussion is also given for the Los Alamos Synoptic Data Set (SDS) which gives a broad overview of the Los Alamos geostationary orbit measurements. The SDS data are plotted in terms of daily average spectra, 3-hour local time averages, and in a variety of statistical formats. The data summarize conditions from mid-1976 through 1978 (S/C 1976-059) and from early 1977 through 1978 (S/C 1977-007). The SDS compilations presented correspond to measurements at 35/sup 0/W, 70/sup 0/W, and 135/sup 0/W geographic longitude and thus are indicative of conditions at 9/sup 0/, 11/sup 0/, and 4.8/sup 0/ geomagnetic latitude, respectively. The bulk of the SDS report presents data plots which are organized according to Carrington solar rotations and, as such, the data are readily comparable to solar rotation-dependent interplanetary conditions. Potential applications of the Synoptic Data Set (available to all interested users in June 1981) are discussed.

  11. Status of the Los Alamos Anger camera

    SciTech Connect

    Seeger, P.A.; Nutter, M.J.

    1985-01-01

    Results of preliminary tests of the neutron Anger camera being developed at Los Alamos are presented. This detector uses a unique encoding scheme involving parellel processing of multiple receptive fields. Design goals have not yet been met, but the results are very encouraging and improvements in the test procedures are expected to show that the detector will be ready for use on a small-angle scattering instrument next year. 3 refs., 4 figs.

  12. Los Alamos National Laboratory Building Cost Index

    SciTech Connect

    Orr, H.D.; Lemon, G.D.

    1983-01-01

    The Los Alamos National Laboratory Building Cost Index indicates that actual escalation since 1970 is near 10% per year. Therefore, the Laboratory will continue using a 10% per year escalation rate for construction estimates through 1985 and a slightly lower rate of 8% per year from 1986 through 1990. The computerized program compares the different elements involved in the cost of a typical construction project, which for our purposes, is a complex of office buildings and experimental laboratores. The input data used in the program consist primarily of labor costs and material and equipment costs. The labor costs are the contractural rates of the crafts workers in the Los Alamos area. For the analysis, 12 field-labor draft categories are used; each is weighted corresponding to the labor craft distribution associated with the typical construction project. The materials costs are current Los Alamos prices. Additional information sources include material and equipment quotes obtained through conversations with vendors and from trade publications. The material and equipment items separate into 17 categories for the analysis and are weighted corresponding to the material and equipment distribution associated with the typical construction project. The building cost index is compared to other national building cost indexes.

  13. Los Alamos National Laboratory building cost index

    SciTech Connect

    Orr, H.D.; Lemon, G.D.

    1982-10-01

    The Los Alamos National Laboratory Building Cost Index indicates that actual escalation since 1970 is near 10% per year. Therefore, the Laboratory will continue using a 10% per year escalation rate for construction estimates through 1985 and a slightly lower rate of 8% per year from 1986 through 1990. The computerized program compares the different elements involved in the cost of a typical construction project, which for our purposes, is a complex of office buildings and experimental laboratories. The input data used in the program consist primarily of labor costs and material and equipment costs. The labor costs are the contractual rates of the crafts workers in the Los Alamos area. For the analysis, 12 field-labor craft categories are used; each is weighted corresponding to the labor craft distribution associated with the typical construction project. The materials costs are current Los Alamos prices. Additional information sources include material and equipment quotes obtained through conversations with vendors and from trade publications. The material and equipment items separate into 17 categories for the analysis and are weighted corresponding to the material and equipment distribution associated with the typical construction project. The building cost index is compared to other national building cost indexes.

  14. Criticality experiments with mixed plutonium and uranium nitrate solution at a plutonium fraction of 0.5 in slab and cylindrical geometry

    SciTech Connect

    Lloyd, R.C.

    1986-12-01

    A series of critical experiments was completed with mixed plutonium-uranium solutions having Pu/(Pu + U) ratios of approximately 0.5. These experiments were a part of the Criticality Data Development Program between the United States Department of Energy (USDOE), and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. A complete description of, and data from, the experiments are included in this report. The experiments were performed with mixed plutonium-uranium solutions in cylindrical and slab geometries and included measurements with a water reflector, a concrete reflector, and without an added reflector. The concentration was varied from 112 to 332 g (Pu + U)/liter. The ratio of plutonium to total heavy metal (plutonium plus uranium) was 52% for all experiments.

  15. Criticality Experiments with Mixed Plutonium and Uranium Nitrate Solution at a Plutonium Fraction of 0.4 in Slab and Cylindrical Geometry

    SciTech Connect

    Lloyd, RC

    1988-04-01

    A series of critical experiments was completed with mixed plutonium-uranium solutions having Pu/(Pu + U) ratios of approximately 0.4. These experiments were a part of the Criticality Data Development Program between the United States Department of Energy (USDOE), and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. A complete description of, and data from, the experiments are included in this report. The experiments were performed with mixed plutonium-uranium solutions in cylinqrical and slab geometries and included measurements with a water reflector, a concrete reflector, and without an added reflector. The concentration was varied from 105 to 436 g (Pu + U)/liter. The ratio of plutonium to total heavy metal (plutonium plus uranium) was 0.4 for all experiments.

  16. Criticality Experiments with Mixed Plutonium and Uranium Nitrate Solution at a Plutonium Fraction of 0.5 in Annular Cylindrical Geometry

    SciTech Connect

    Lloyd, RC

    1988-04-01

    A series of critical experiments was completed with mixed plutonium-uranium solutions having Pu/(Pu + U) ratios of approximately 0.5. These experiments were a part of the Criticality Data Development Program between the United States Department of Energy (USDOE), and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. A complete description of, and data from, the experiments are included in this report. The experiments were performed with mixed plutonium-uranium solutions in annular cylindrical geometry. The measurements were made with a water reflector. The central region included a concrete annular cylinder containing B{sub 4}C. Interior to the concrete insert was a stainless steel bottle containing plutonium-uranium solution. The concentration of the solution in the annular region was varied from 116 to 433 g (Pu + U)/liter. The ratio of plutonium to total heavy metal (plutonium plus uranium) was 52% for all experiments.

  17. The Development, Content, Design, and Conduct of the 2011 Piloted US DOE Nuclear Criticality Safety Program Criticality Safety Engineering Training and Education Project

    SciTech Connect

    Hopper, Calvin Mitchell

    2011-01-01

    In May 1973 the University of New Mexico conducted the first nationwide criticality safety training and education week-long short course for nuclear criticality safety engineers. Subsequent to that course, the Los Alamos Critical Experiments Facility (LACEF) developed very successful 'hands-on' subcritical and critical training programs for operators, supervisors, and engineering staff. Since the inception of the US Department of Energy (DOE) Nuclear Criticality Technology and Safety Project (NCT&SP) in 1983, the DOE has stimulated contractor facilities and laboratories to collaborate in the furthering of nuclear criticality as a discipline. That effort included the education and training of nuclear criticality safety engineers (NCSEs). In 1985 a textbook was written that established a path toward formalizing education and training for NCSEs. Though the NCT&SP went through a brief hiatus from 1990 to 1992, other DOE-supported programs were evolving to the benefit of NCSE training and education. In 1993 the DOE established a Nuclear Criticality Safety Program (NCSP) and undertook a comprehensive development effort to expand the extant LACEF 'hands-on' course specifically for the education and training of NCSEs. That successful education and training was interrupted in 2006 for the closing of the LACEF and the accompanying movement of materials and critical experiment machines to the Nevada Test Site. Prior to that closing, the Lawrence Livermore National Laboratory (LLNL) was commissioned by the US DOE NCSP to establish an independent hands-on NCSE subcritical education and training course. The course provided an interim transition for the establishment of a reinvigorated and expanded two-week NCSE education and training program in 2011. The 2011 piloted two-week course was coordinated by the Oak Ridge National Laboratory (ORNL) and jointly conducted by the Los Alamos National Laboratory (LANL) classroom education and facility training, the Sandia National

  18. Final Environmental Impact Statement for the Proposed Relocation of Technical Area 18 Capabilities and Materials at the Los Alamos National Laboratory

    SciTech Connect

    N /A

    2002-09-20

    The National Nuclear Security Administration, a separately organized agency within DOE, is responsible for providing the Nation with nuclear weapons, ensuring the safety and reliability of those nuclear weapons, and supporting programs that reduce global nuclear proliferation. These missions are accomplished with a core team of highly trained nuclear experts. One of the major training facilities for these personnel is located at Technical Area 18 (TA-18), within the Los Alamos National Laboratory (LANL), Los Alamos, New Mexico. Principal TA-18 operational activities involve research in and the design, development, construction, and application of experiments on nuclear criticality. Though TA-18 is judged to be secure by DOE's independent inspection office, its buildings and infrastructure are from 30 to more than 50 years old and are increasingly expensive to maintain and operate. Additionally, the TA-18 operations are located in a relatively isolated area, resulting in increasingly high costs to maintain a security Category I infrastructure. NNSA wishes to maintain the important capabilities currently provided at TA-18 in a manner that reduces the long-term costs for safeguards and security. NNSA proposes to accomplish this by relocating the TA-18 security Category I/II capabilities and materials to new locations. The TA-18 Relocation EIS evaluates the potential direct, indirect, and cumulative environmental impacts associated with this proposed action at the following DOE sites: (1) a different site at LANL at Los Alamos, New Mexico; (2) the Sandia National Laboratories/New Mexico at Albuquerque, New Mexico; (3) the Nevada Test Site near Las Vegas, Nevada (the Preferred Alternative); and (4) the Argonne National Laboratory-West near Idaho Falls, Idaho. The EIS also analyzes the alternatives of upgrading the existing TA-18 facilities and the No Action Alternative of maintaining the operations at the current TA-18 location.

  19. Critical Drivers for Safety Culture: Examining Department of Energy and U.S. Army Operational Experiences - 12382

    SciTech Connect

    Lowes, Elizabeth A.

    2012-07-01

    Evaluating operational incidents can provide a window into the drivers most critical to establishing and maintaining a strong safety culture, thereby minimizing the potential project risk associated with safety incidents. By examining U.S. Department of Energy (DOE) versus U.S. Army drivers in terms of regulatory and contract requirements, programs implemented to address the requirements, and example case studies of operational events, a view of the elements most critical to making a positive influence on safety culture is presented. Four case studies are used in this evaluation; two from DOE and two from U.S. Army experiences. Although the standards guiding operations at these facilities are different, there are many similarities in the level of hazards, as well as the causes and the potential consequences of the events presented. Two of the incidents examined, one from a DOE operation and the other from a U.S. Army facility, resulted in workers receiving chemical burns. The remaining two incidents are similar in that significant conduct of operations failures occurred resulting in high-level radioactive waste (in the case of the DOE facility) or chemical agent (in the case of the Army facility) being transferred outside of engineering controls. A review of the investigation reports for all four events indicates the primary causes to be failures in work planning leading to ineffective hazard evaluation and control, lack of procedure adherence, and most importantly, lack of management oversight to effectively reinforce expectations for safe work planning and execution. DOE and Army safety programs are similar, and although there are some differences in contractual requirements, the expectations for safe performance are essentially the same. This analysis concludes that instilling a positive safety culture comes down to management leadership and engagement to (1) cultivate an environment that values a questioning attitude and (2) continually reinforce expectations

  20. Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term Irradiation at Elevated Temperature: Critical Experiments

    SciTech Connect

    Was, Gary; Jiao, Zhijie; Allen, Todd; Yang, Yong

    2013-12-20

    radiation on these important materials. The objective of this project is to conduct critical experiments to understand the evolution of microstructural and microchemical features (loops, voids, precipitates, and segregation) and mechanical properties (hardening and creep) under high temperature and full dose range radiation, including the effect of differences in the initial material composition and microstructure on the microstructural response, including key questions related to saturation of the microstructure at high doses and temperatures.

  1. SNM holdup assessment of Los Alamos exhaust ducts. Final report

    SciTech Connect

    Marshall, R.S.

    1994-02-01

    Fissile material holdup in glovebox and fume hood exhaust ducting has been quantified for all Los Alamos duct systems. Gamma-based, nondestructive measurements were used to quantify holdup. The measurements were performed during three measurement campaigns. The first campaign, Phase I, provided foot-by-foot, semiquantitative measurement data on all ducting. These data were used to identify ducting that required more accurate (quantitative) measurement. Of the 280 duct systems receiving Phase I measurements, 262 indicated less than 50 g of fissile holdup and 19 indicated fissile holdup of 50 or more grams. Seven duct systems were measured in a second campaign, called Series 1, Phase II. Holdup estimates on these ducts ranged from 421 g of {sup 235}U in a duct servicing a shut-down uranium-machining facility to 39 g of {sup 239}Pu in a duct servicing an active plutonium-processing facility. Measurements performed in the second campaign proved excessively laborious, so a third campaign was initiated that used more efficient instrumentation at some sacrifice in measurement quality. Holdup estimates for the 12 duct systems measured during this third campaign ranged from 70 g of {sup 235}U in a duct servicing analytical laboratories to 1 g of {sup 235}U and 1 g of {sup 239}Pu in a duct carrying exhaust air to a remote filter building. These quantitative holdup estimates support the conclusion made at the completion of the Phase I measurements that only ducts servicing shut-down uranium operations contain about 400 g of fissile holdup. No ventilation ducts at Los Alamos contain sufficient fissile material holdup to present a criticality safety concern.

  2. Personnel neutron dosimetry improvements at Los Alamos National Laboratory

    SciTech Connect

    Harvey, W.F.; Hoffman, J.M.; Brake, R.J.; Bliss, J.L.

    1992-08-01

    We are investigating methods to improve neutron dosimetry at Los Alamos National Laboratory (LANL) using the track etch dosemeter CR-39. Specifically, use of CR-39 for dynamic environments, typically encountered at the LANL Plutonium Facility, is shown to be a superior method for personnel neutron dosimetry when compared to the currently used TLD system. The results of glovebox experiments simulating hydrogenous shielding used at LANL, temporal variations of neutron correction factors used at the Plutonium Facility, trial implementation at this facility and preliminary neutron spectroscopy measurements are presented and compared to reference dosimetry measurements. Our results confirm that use of a TLD system in a facility implementing hydrogenous shielding requires frequent field re-calibration. When such correction factors are not re-evaluated frequently, or are maintained at pre-shielding levels, significant (i.e., 2- to 3-fold) overestimation of the neutron dose equivalent can occur.

  3. Personnel neutron dosimetry improvements at Los Alamos National Laboratory

    SciTech Connect

    Harvey, W.F.; Hoffman, J.M.; Brake, R.J. ); Bliss, J.L. . Dept. of Nuclear Engineering)

    1992-01-01

    We are investigating methods to improve neutron dosimetry at Los Alamos National Laboratory (LANL) using the track etch dosemeter CR-39. Specifically, use of CR-39 for dynamic environments, typically encountered at the LANL Plutonium Facility, is shown to be a superior method for personnel neutron dosimetry when compared to the currently used TLD system. The results of glovebox experiments simulating hydrogenous shielding used at LANL, temporal variations of neutron correction factors used at the Plutonium Facility, trial implementation at this facility and preliminary neutron spectroscopy measurements are presented and compared to reference dosimetry measurements. Our results confirm that use of a TLD system in a facility implementing hydrogenous shielding requires frequent field re-calibration. When such correction factors are not re-evaluated frequently, or are maintained at pre-shielding levels, significant (i.e., 2- to 3-fold) overestimation of the neutron dose equivalent can occur.

  4. Decommissioning the UHTREX Reactor Facility at Los Alamos, New Mexico

    SciTech Connect

    Salazar, M.; Elder, J.

    1992-08-01

    The Ultra-High Temperature Reactor Experiment (UHTREX) facility was constructed in the late 1960s to advance high-temperature and gas-cooled reactor technology. The 3-MW reactor was graphite moderated and helium cooled and used 93% enriched uranium as its fuel. The reactor was run for approximately one year and was shut down in February 1970. The decommissioning of the facility involved removing the reactor and its associated components. This document details planning for the decommissioning operations which included characterizing the facility, estimating the costs of decommissioning, preparing environmental documentation, establishing a system to track costs and work progress, and preplanning to correct health and safety concerns in the facility. Work to decommission the facility began in 1988 and was completed in September 1990 at a cost of $2.9 million. The facility was released to Department of Energy for other uses in its Los Alamos program.

  5. Study of polyelectrolytes for Los Alamos National Laboratory. Final report

    SciTech Connect

    Labonne, N.

    1994-11-01

    To assess the safety of a potential radioactive waste repository, analysis of the fluid solution containing low levels of activity need to be performed. In some cases, the radioactivity would be so weak (3--30 pCi/L) that the solution must be concentrated for measurement. For this purpose, Los Alamos National Laboratory scientists are synthesizing some water soluble polyelectrolytes, which, because they are strong complexing agents for inorganic cations, can concentrate the radioelements in solution. To assist in characterization of these polyelectrolytes, the author has performed experiments to determine physico-chemical constants, such as pKa values and stability constants. The complexation constants between both polyelectrolytes and europium were determined by two methods: solvent extraction and ion exchange. Results are presented.

  6. The performance of the Los Alamos Proton Storage Ring

    SciTech Connect

    Lawrence, G.P.

    1987-03-01

    The Proton Storage Ring (PSR) now in operation at Los Alamos is a high-current accumulator that generates intense 800-MeV proton pulses for driving the Los Alamos Neutron Scattering Center (LANSCE) spallation source. The ring compresses up to 1000-..mu..s-long macropulses from the LAMPF linac into 250-ns bunches and ejects them to a neutron-production target, providing an output optimized for thermal-neutron-scattering research. The design pulse rate and peak pulse intensity of PSR are 12 Hz and 5.2 . 10/sup 13/ protons per pulse (ppp), yielding 100 ..mu..A average current when full performance is reached. This paper summarizes commissioning results and operational experience in the two years since first beam. The PSR has operated in production at average currents up to 30 ..mu..A and has reached a peak intensity of 3.4 . 10/sup 13/ ppp. These achievements represents 30% and 65% of the design objectives. Higher current production has been inhibited by beam losses during accumulation and extraction. Therefore, experiments to understand loss mechanisms have occupied a large fraction of the commissioning effort. Correction of an extraction-channel aperture restriction identified late in 1986 should dramatically reduce extraction losses, which will permit higher current production in 1987. Beam tests in the 10/sup 13/-ppp range have indicated the presence of a collective instability tentatively identified as transverse. However, by suitable parameter adjustments, the instability threshold can be pushed above the top charge-level attainable with the existing H /sup -/ source.

  7. ORSPHERE: CRITICAL, BARE, HEU(93.2)-METAL SPHERE

    SciTech Connect

    Margaret A. Marshall

    2013-09-01

    In the early 1970’s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) in an attempt to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950’s (HEU-MET-FAST-001). The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with the GODIVA I experiments. “The very accurate description of this sphere, as assembled, establishes it as an ideal benchmark for calculational methods and cross-section data files.” (Reference 1) While performing the ORSphere experiments care was taken to accurately document component dimensions (±0. 0001 in. for non-spherical parts), masses (±0.01 g), and material data The experiment was also set up to minimize the amount of structural material in the sphere proximity. A three part sphere was initially assembled with an average radius of 3.4665 in. and was then machined down to an average radius of 3.4420 in. (3.4425 in. nominal). These two spherical configurations were evaluated and judged to be acceptable benchmark experiments; however, the two experiments are highly correlated.

  8. Commercialization of Los Alamos National Laboratory technologies via small businesses. Final report

    SciTech Connect

    Brice, R.; Cartron, D.; Rhyne, T.; Schulze, M.; Welty, L.

    1997-06-01

    Over the past decade, numerous companies have been formed to commercialize research results from leading U.S. academic and research institutions. Emerging small businesses in areas such as Silicon Valley, Boston`s Route 128 corridor, and North Carolina`s Research Triangle have been especially effective in moving promising technologies from the laboratory bench to the commercial marketplace--creating new jobs and economic expansion in the process. Unfortunately, many of the U.S. national laboratories have not been major participants in this technology/commercialization activity, a result of a wide variety of factors which, until recently, acted against successful commercialization. This {open_quotes}commercialization gap{close_quotes} exists partly due to a lack, within Los Alamos in particular and the DOE in general, of in-depth expertise and experience in such business areas as new business development, securities regulation, market research and the determination of commercial potential, the identification of entrepreneurial management, marketing and distribution, and venture capital sources. The immediate consequence of these factors is the disappointingly small number of start-up companies based on technologies from Los Alamos National Laboratory that have been attempted, the modest financial return Los Alamos has received from these start-ups, and the lack of significant national recognition that Los Alamos has received for creating and commercializing these technologies.

  9. Plant Uptake of Organic Pollutants from Soil: A Critical Review ofBioconcentration Estimates Based on Modelsand Experiments

    SciTech Connect

    McKone, Thomas E.; Maddalena, Randy L.

    2007-01-01

    The role of terrestrial vegetation in transferring chemicals from soil and air into specific plant tissues (stems, leaves, roots, etc.) is still not well characterized. We provide here a critical review of plant-to-soil bioconcentration ratio (BCR) estimates based on models and experimental data. This review includes the conceptual and theoretical formulations of the bioconcentration ratio, constructing and calibrating empirical and mathematical algorithms to describe this ratio and the experimental data used to quantify BCRs and calibrate the model performance. We first evaluate the theoretical basis for the BCR concept and BCR models and consider how lack of knowledge and data limits reliability and consistency of BCR estimates. We next consider alternate modeling strategies for BCR. A key focus of this evaluation is the relative contributions to overall uncertainty from model uncertainty versus variability in the experimental data used to develop and test the models. As a case study, we consider a single chemical, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and focus on variability of bioconcentration measurements obtained from 81 experiments with different plant species, different plant tissues, different experimental conditions, and different methods for reporting concentrations in the soil and plant tissues. We use these observations to evaluate both the magnitude of experimental variability in plant bioconcentration and compare this to model uncertainty. Among these 81 measurements, the variation of the plant/soil BCR has a geometric standard deviation (GSD) of 3.5 and a coefficient of variability (CV-ratio of arithmetic standard deviation to mean) of 1.7. These variations are significant but low relative to model uncertainties--which have an estimated GSD of 10 with a corresponding CV of 14.

  10. NEPA and NHPA- successful decommissioning of historic Manhattan Project properties at Los Alamos National Laboratory, Los Alamos, New Mexico

    SciTech Connect

    McGehee, E.D.; Pendergrass, A.K.

    1997-05-21

    This paper describes experiences at Los Alamos National Laboratory during the process of planning and executing decommissioning and decontamination activities on a number of properties constructed as part of the Manhattan project. Many of these buildings had been abandoned for many years and were in deteriorating condition, in addition to being contaminated with asbestos, lead based paints and high explosive residues. Due to the age and use of the structures they were evaluated against criteria for the National Register of Historic Places. This process is briefly reviewed, along with the results, as well as actions implemented as a result of the condition and safety of the structures. A number of the structures have been decontaminated and demolished. Planning is still ongoing for the renovation of one structure, and the photographic and drawing records of the properties is near completion.

  11. Nuclear criticality safety experiments, calculations, and analyses - 1958 to 1982. Volume 2. Summaries. Complilation of papers from the Transactions of the American Nuclear Society

    SciTech Connect

    Koponen, B.L.; Hampel, V.E.

    1982-10-21

    This compilation contains 688 complete summaries of papers on nuclear criticality safety as presented at meetings of the American Nuclear Society (ANS). The selected papers contain criticality parameters for fissile materials derived from experiments and calculations, as well as criticality safety analyses for fissile material processing, transport, and storage. The compilation was developed as a component of the Nuclear Criticality Information System (NCIS) now under development at the Lawrence Livermore National Laboratory. The compilation is presented in two volumes: Volume 1 contains a directory to the ANS Transaction volume and page number where each summary was originally published, the author concordance, and the subject concordance derived from the keyphrases in titles. Volume 2 contains-in chronological order-the full-text summaries, reproduced here by permission of the American Nuclear Society from their Transactions, volumes 1-41.

  12. Experiments on small-size fast critical fuel assemblies at the AKSAMIT facility and their use for development of computational models

    NASA Astrophysics Data System (ADS)

    Glushkov, E. S.; Glushkov, A. E.; Gomin, E. A.; Daneliya, S. B.; Zimin, A. A.; Kalugin, M. A.; Kapitonova, A. V.; Kompaniets, G. V.; Moroz, N. P.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

    2013-12-01

    Small-size fast critical assemblies with highly enriched fuel at the AKSAMIT facility are described in detail. Computational models of the critical assemblies at room temperature are given. The calculation results for the critical parameters are compared with the experimental data. A good agreement between the calculations and the experimental data is shown. The physical models developed for the critical assemblies, as well as the experimental results, can be applied to verify various codes intended for calculation of the neutronic characteristics of small-size fast nuclear reactors. For these experiments, the results computed using the codes of the MCU family show a high quality of the neutron data and of the physical models used.

  13. An Investigation of the Effects of Field Experience and Critical Reflection on Pre-Service Teachers' Beliefs about Diversity

    ERIC Educational Resources Information Center

    Renn, Peter C.

    2012-01-01

    This study was conducted to investigate the effects of critical reflection and field experiences on pre-service teachers' beliefs about diversity. A convenience sample of 64 students enrolled in two sections of an education course at a Midwestern university participated in the study. Participants in the intervention group completed field…

  14. Writing Critical Race Theory and Method: A Composite Counterstory on the Experiences of Black Teachers in New Orleans Post-Katrina

    ERIC Educational Resources Information Center

    Cook, Daniella Ann; Dixson, Adrienne D.

    2013-01-01

    Using a critical race theory lens, the authors propose a way of writing race research using composite counterstories. Drawing on data from a yearlong study of school rebuilding in the time period immediately after Hurricane Katrina devastated the City of New Orleans, the authors examine the experiences of African-American educators in the school…

  15. Negotiating Identity in a Bubble: A Critical Race Analysis of African American High School Students' Experiences in an Elite, Independent School

    ERIC Educational Resources Information Center

    DeCuir-Gunby, Jessica T.

    2007-01-01

    This study used critical race theory to examine how African American adolescents negotiated race and class identity at Wells Academy, a predominately white, independent school. Interviews were conducted, exploring the experiences of six African American high school students. Their counterstories were analyzed focusing on the critique of…

  16. Los Alamos Before and After the Fire

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On May 4, 2000, a prescribed fire was set at Bandelier National Monument, New Mexico, to clear brush and dead and dying undergrowth to prevent a larger, subsequent wildfire. Unfortunately, due to high winds and extremely dry conditions in the surrounding area, the prescribed fire quickly raged out of control and, by May 10, the blaze had spread into the nearby town of Los Alamos. In all, more than 20,000 people were evacuated from their homes and more than 200 houses were destroyed as the flames consumed about 48,000 acres in and around the Los Alamos area. The pair of images above were acquired by the Enhanced Thematic Mapper Plus (ETM+) sensor, flying aboard NASA's Landsat 7 satellite, shortly before the Los Alamos fire (top image, acquired April 14) and shortly after the fire was extinguished (lower image, June 17). The images reveal the extent of the damage caused by the fire. Combining ETM+ channels 7, 4, and 2 (one visible and two infrared channels) results in a false-color image where vegetation appears as bright to dark green. Forested areas are generally dark green while herbaceous vegetation is light green. Rangeland or more open areas appear pink to light purple. Areas with extensive pavement or urban development appear light blue or white to purple. Less densely-developed residential areas appear light green and golf courses are very bright green. In the lower image, the areas recently burned appear bright red. Landsat 7 data courtesy United States Geological Survey EROS DataCenter. Images by Robert Simmon, NASA GSFC.

  17. Towards a conceptual model of motorcyclists' Risk Awareness: a comparative study of riding experience effect on hazard detection and situational criticality assessment.

    PubMed

    Bellet, Thierry; Banet, Aurélie

    2012-11-01

    This research investigates risk awareness abilities among different populations of motorcyclists. Risk awareness is defined here as an extension of the Situational Awareness theory applied to critical driving situations. This study is more particularly focused on two main cognitive abilities supporting risk awareness: hazard detection, corresponding to riders' skill to perceive critical event occurring in the road environment and to identify it as a threat, and situational criticality assessment, corresponding to a subjective assessment of the accident risk. From this theoretical framework, the aim is to compare motorcyclists' performances in risk awareness according to their experience in motorcycling. Four populations of motorcyclists are investigated: Professional (Policemen), Experienced riders, Novices, and Beginners. Method implemented is based of a set of 25 video sequences of driving situations presenting a risk of collision. Participants' task was firstly to stop the video film if they detect a hazard. Then, at the end of each sequence, they have also to assess the criticality of the driving situation as a whole, with a Likert scale (from 0 to 100% of criticality). Results obtained show that cognitive abilities in both (i) hazard detection and (ii) situational criticality assessment depend of the riding experience, and are learnt from two different timing. On one side, Professional and Experienced riders obtained better results than Novices and Beginners for hazard perception (i.e. shortest reaction time). In terms of situational criticality assessment, Beginners underestimate the situational risk and seem overconfident in their abilities to manage the situational risk, against Novices, Professional and Experienced riders, who have better competences in criticality assessment. From these empirical results, a conceptual model of motorcyclists' Risk Awareness is proposed. PMID:23036392

  18. A Journey From Sandia To Los Alamos - 12465

    SciTech Connect

    Goyal, K.K.; Humphrey, B.J.; Krause, T.J.; Gluth, J.W.; Kiefer, M.L.; Haynes, S.

    2012-07-01

    The U.S. Department of Energy (DOE) relies on laboratory experiments and computer-based models to verify the reliability of the nation's nuclear stockpile. Sandia National Laboratories/New Mexico (SNL/NM) tests various materials in extreme environments designed to mimic those of nuclear explosions using the Z machine. The Z machine is a key tool in the National Nuclear Security Administration's (NNSA) stockpile stewardship mission and is used to study the dynamic properties of nuclear weapon materials. In 2006, SNL/NM and Los Alamos National Laboratory (LANL) signed a Memorandum of Understanding (MOU) defining experiments to be conducted in the Z machine involving plutonium (Pu) provided by LANL. Five Pu experiments have been completed with as many as 20 more planned through 2016. The experimental containment vessel used for the experiment and containing the Pu residues, becomes transuranic (TRU) waste after the experiment and termination of safeguards and is considered a LANL waste stream. Each containment vessel is placed in a 55-gallon Type A drum or standard waste box (SWB) for shipment back to LANL for final certification and eventual disposal at the Waste Isolation Pilot Plant (WIPP). The experimental containment vessels are greater than 99% metallic materials (ferrous and non-ferrous metals). In addition to the Pu targets, detonators with high explosives (HE) are used in the experiments to isolate the containment vessel from the Z machine as energy is delivered to the Pu samples. The characterization requirements, transportation issues, required documentation, and the approvals needed before shipments were challenging and required close coordination between SNL/NM, Sandia Site Office, LANL, Los Alamos Site Office, Washington TRU Solutions, Inc., the Central Characterization Project, and the Carlsbad Field Office. Between 2006 and 2010, representatives from SNL/NM and LANL worked to develop an approved path forward to meet the requirements of all stakeholders

  19. LAMPF II workshop, Los Alamos National Laboratory, Los Alamos, New Mexico, February 1-4, 1982

    SciTech Connect

    Thiessen, H.A.

    1982-01-01

    This report contains the proceedings of the first LAMPF II Workshop held at Los Alamos February 1 to 4, 1982. Included are the talks that were available in written form. The conclusion of the participants was that there are many exciting areas of physics that will be addressed by such a machine.

  20. Biological assessment for the effluent reduction program, Los Alamos National Laboratory, Los Alamos, New Mexico

    SciTech Connect

    Cross, S.P.

    1996-08-01

    This report describes the biological assessment for the effluent recution program proposed to occur within the boundaries of Los Alamos National Laboratory. Potential effects on wetland plants and on threatened and endangered species are discussed, along with a detailed description of the individual outfalls resulting from the effluent reduction program.

  1. Analysis of muon radiography of the Toshiba nuclear critical assembly reactor

    SciTech Connect

    Morris, C. L.; Bacon, Jeffery; Borozdin, Konstantin; Fabritius, J. M.; Perry, John; Ramsey, John; Ban, Yuichiro; Izumi, Mikio; Sano, Yuji; Yoshida, Noriyuki; Miyadera, Haruo; Mizokami, Shinya; Otsuka, Yasuyuki; Yamada, Daichi; Sugita, Tsukasa; Yoshioka, Kenichi

    2014-01-13

    A 1.2 × 1.2 m{sup 2} muon tracker was moved from Los Alamos to the Toshiba facility at Kawasaki, Japan, where it was used to take ∼4 weeks of data radiographing the Toshiba Critical Assembly Reactor with cosmic ray muons. In this paper, we describe the analysis procedure, show results of this experiment, and compare the results to Monte Carlo predictions. The results validate the concept of using cosmic rays to image the damaged cores of the Fukushima Daiichi reactors.

  2. Analysis of muon radiography of the Toshiba nuclear critical assembly reactor

    NASA Astrophysics Data System (ADS)

    Morris, C. L.; Bacon, Jeffery; Ban, Yuichiro; Borozdin, Konstantin; Fabritius, J. M.; Izumi, Mikio; Miyadera, Haruo; Mizokami, Shinya; Otsuka, Yasuyuki; Perry, John; Ramsey, John; Sano, Yuji; Sugita, Tsukasa; Yamada, Daichi; Yoshida, Noriyuki; Yoshioka, Kenichi

    2014-01-01

    A 1.2 × 1.2 m2 muon tracker was moved from Los Alamos to the Toshiba facility at Kawasaki, Japan, where it was used to take ˜4 weeks of data radiographing the Toshiba Critical Assembly Reactor with cosmic ray muons. In this paper, we describe the analysis procedure, show results of this experiment, and compare the results to Monte Carlo predictions. The results validate the concept of using cosmic rays to image the damaged cores of the Fukushima Daiichi reactors.

  3. Los Alamos National Laboratory computer benchmarking 1982

    SciTech Connect

    Martin, J.L.

    1983-06-01

    Evaluating the performance of computing machinery is a continual effort of the Computer Research and Applications Group of the Los Alamos National Laboratory. This report summarizes the results of the group's benchmarking activities performed between October 1981 and September 1982, presenting compilation and execution times as well as megaflop rates for a set of benchmark codes. Tests were performed on the following computers: Cray Research, Inc. (CRI) Cray-1S; Control Data Corporation (CDC) 7600, 6600, Cyber 73, Cyber 825, Cyber 835, Cyber 855, and Cyber 205; Digital Equipment Corporation (DEC) VAX 11/780 and VAX 11/782; and Apollo Computer, Inc., Apollo.

  4. Ultraprecision machining of optics at Los Alamos

    SciTech Connect

    Rhorer, R.L.; Gauler, A.L.; Colston, E.W.; Ruhe, J.R.

    1982-01-01

    Ultraprecision machine tools are used at the Los Alamos National Laboratory for single-point diamond turning of optics and other precision parts. Measurements of a 50-mm-diam copper flat illustrate the quality of a part that can be machined on the Moore No. 3 lathe. Measurements of a 0.4-m-diam aluminum mirror with a 20-m radius of curvature are presented as an example of a part machined on the Moore No. 5 lathe. A varying frequency sine wave grating shows a type of special optical grating that can be produced using the Pneumo lathe.

  5. Ultraprecision machining of optics at Los Alamos

    SciTech Connect

    Rhorer, R.L.; Gauler, A.L.; Colston, E.W.; Ruhe, J.R.

    1981-01-01

    Ultraprecision machine tools are used at Los Alamos for single point diamond turning of optics and other precision parts. Measurements of a 50-mm-dia copper flat are used to illustrate the quality of a part which can be machined on the Moore No. 3 lathe. Measurements of a 0.4-m-dia aluminum mirror with a 20-m radius-of-curvature are presented as an example of a part machined on the Moore No. 5 lathe. A varying frequency sine wave grating is used to show a type of special optical grating which can be produced using the Pneumo lathe.

  6. Environmental Programs at Los Alamos National Laboratory

    SciTech Connect

    Jones, Patricia

    2012-07-11

    Summary of this project is: (1) Teamwork, partnering to meet goals - (a) Building on cleanup successes, (b) Solving legacy waste problems, (c) Protecting the area's environment; (2) Strong performance over the past three years - (a) Credibility from four successful Recovery Act Projects, (b) Met all Consent Order milestones, (c) Successful ramp-up of TRU program; (3) Partnership between the National Nuclear Security Administration's Los Alamos Site Office, DOE Carlsbad Field Office, New Mexico Environment Department, and contractor staff enables unprecedented cleanup progress; (4) Continued focus on protecting water resources; and (5) All consent order commitments delivered on time or ahead of schedule.

  7. Criticality Model

    SciTech Connect

    A. Alsaed

    2004-09-14

    The ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003) presents the methodology for evaluating potential criticality situations in the monitored geologic repository. As stated in the referenced Topical Report, the detailed methodology for performing the disposal criticality analyses will be documented in model reports. Many of the models developed in support of the Topical Report differ from the definition of models as given in the Office of Civilian Radioactive Waste Management procedure AP-SIII.10Q, ''Models'', in that they are procedural, rather than mathematical. These model reports document the detailed methodology necessary to implement the approach presented in the Disposal Criticality Analysis Methodology Topical Report and provide calculations utilizing the methodology. Thus, the governing procedure for this type of report is AP-3.12Q, ''Design Calculations and Analyses''. The ''Criticality Model'' is of this latter type, providing a process evaluating the criticality potential of in-package and external configurations. The purpose of this analysis is to layout the process for calculating the criticality potential for various in-package and external configurations and to calculate lower-bound tolerance limit (LBTL) values and determine range of applicability (ROA) parameters. The LBTL calculations and the ROA determinations are performed using selected benchmark experiments that are applicable to various waste forms and various in-package and external configurations. The waste forms considered in this calculation are pressurized water reactor (PWR), boiling water reactor (BWR), Fast Flux Test Facility (FFTF), Training Research Isotope General Atomic (TRIGA), Enrico Fermi, Shippingport pressurized water reactor, Shippingport light water breeder reactor (LWBR), N-Reactor, Melt and Dilute, and Fort Saint Vrain Reactor spent nuclear fuel (SNF). The scope of this analysis is to document the criticality computational method. The criticality

  8. The search for safety, control, and voice for mothers living with the legacy of childhood violence experiences: a critical feminist narrative inquiry.

    PubMed

    Pitre, Nicole Y; Kushner, Kaysi E; Hegadoren, Kathy M

    2011-01-01

    We explored the experiences of 12 women who mothered their children while they encountered challenges stemming from the legacy of childhood violence experiences. We examined the participants' narratives through critical, feminist, and symbolic interaction lenses to locate the forces and conditions facilitating and constraining women's mothering choices and decisions. Women's stories revealed their agency in the face of enduring distrust experiences. Women were determined to "change the story." They met pervasive self-doubt with a "search for anchors" and "constant comparisons." Persistent distrust of others meant women relied on "hypervigilance" and "gatekeeping." Implications for knowledge development, research, and practice are discussed. PMID:21822073

  9. The large area crop inventory experiment: An experiment to demonstrate how space-age technology can contribute to solving critical problems here on earth

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The large area crop inventory experiment is being developed to predict crop production through satellite photographs. This experiment demonstrates how space age technology can contribute to solving practical problems of agriculture management.

  10. Recent diagnostic development for inertial confinement fusion research at Los Alamos National Laboratory

    SciTech Connect

    Murphy, T.J.; Oertel, J.A.; Archuleta, T.N.

    1997-09-01

    Inertial Confinement Fusion (ICF) experiments require sophisticated diagnostics with temporal resolution measured in tens of picoseconds and spatial resolutions measured in microns. The Los Alamos ICF Program is currently supporting a number of diagnostics on the Nova and Triden laser facilities, and is developing new diagnostics for use on the Omega laser facility. New systems and technologies are being developed for use on the National Ignition Facility, which is expected to be operational early in the next decade.

  11. Automatic beam position control at Los Alamos Spallation Radiation Effects Facility (LASREF)

    SciTech Connect

    Oothoudt, M.; Pillai, C.; Zumbro, M.

    1997-08-01

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual methods to control the position of the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp is used to automatically adjust steering magnets to maintain beam position to required tolerances.

  12. Audit of personal property management at Los Alamos National Laboratory

    SciTech Connect

    Not Available

    1993-12-07

    The Department of Energy`s (Department) Albuquerque Operations Office (Albuquerque) and the Los Alamos National Laboratory (Los Alamos) are responsible for ensuring that Los Alamos maintains an efficient and effective personal property management system that protects, identifies, and controls Government-owned personal property in accordance with applicable regulations. Albuquerque is responsible for reviewing and approving Los Alamos` personal property management system. Los Alamos is responsible for ensuring that personal property is properly protected, identified, and controlled. The audit disclosed that Los Alamos did not have an efficient and effective personal property management system to ensure that personal property was adequately protected, identified, and controlled. In addition, Albuquerque did not approve or disapprove Los Alamos` personal property management system consistent with Federal and Department regulations. Specifically, the audit showed that Los Alamos did not account for $11.6 million of personal property. In addition, $22.2 million of personal property was not properly recorded in the database, $61.7 million of personal property could not be inventoried, and loans to employees and other entities were not adequately justified. As a result, from a total personal property inventory of approximately $1 billion, it is estimated that $100 million of personal property may not be accounted for, and $207 million may not be correctly recorded in the database. Moreover, substantial amounts of personal property on loan to employees and other entities were at risk of unauthorized use. Albuquerque concurred with the finding and agreed to implement the corrective actions recommended in the report.

  13. The Climate at Los Alamos; Are we measurement changes?

    SciTech Connect

    Dewart, Jean Marie

    2015-04-16

    A new report shows new graphic displays of the weather trends in Los Alamos, New Mexico, and at the Los Alamos National Laboratory (LANL). The graphs show trends of average, minimum average, and maximum average temperature for summer and winter months going back decades. Records of summer and winter precipitation are also included in the report.

  14. Radionuclide concentrations in pinto beans, sweet corn, and zucchini squash grown in Los Alamos Canyon at Los Alamos National Laboratory

    SciTech Connect

    Fresquez, P.R.; Mullen, M.A.; Naranjo, L. Jr.; Armstrong, D.R.

    1997-05-01

    Pinto beans, sweet corn, and zucchini squash (Cucurbita pepo var. black beauty) were grown in a randomized complete-block field/pot experiment at a site that contained the highest observed levels of surface gross gamma radioactivity within Los Alamos Canyon (LAC) at Los Alamos National Laboratory. Soils as well as washed edible and nonedible crop tissues were analyzed for various radionuclides and heavy metals . Most radionuclides, with the exception of {sup 3}H and {sup tot}U, in soil from LAC were detected in significantly higher concentrations (p <0.01) than in soil collected from regional background (RBG) locations. Similarly, most radionuclides in edible crop portions of beans, squash, and corn were detected in significantly higher (p <0.01 and 0.05) concentrations than RBG. Most soil-to-plant concentration ratios for radionuclides in edible and nonedible crop tissues from LAC were within the default values given by the Nuclear Regulatory Commission and Environmental Protection Agency. All heavy metals in soils, as well as edible and nonedible crop tissues grown in soils from LAC, were within RBG concentrations. Overall, the total maximum net positive committed effective dose equivalent (CEDE)--the CEDE plus two sigma for each radioisotope minus background and then all positive doses summed--to a hypothetical 50-year resident that ingested 160 kg of beans, corn, and squash in equal proportions, was 74 mrem y{sup -1}. This dose was below the International Commission on Radiological Protection permissible dose limit (PDL) of 100 mrem y{sup -1} from all pathways; however, the addition of other internal and external exposure route factors may increase the overall dose over the PDL. Also, the risk of an excess cancer fatality, based on 74 mrem y{sup -1}, was 3.7 x 10{sup -5} (37 in a million), which is above the Environmental Protection Agency`s (acceptable) guideline of one in a million. 31 refs., 15 tabs.

  15. Los Alamos High-Brightness Accelerator FEL (HIBAF) facility

    SciTech Connect

    Cornelius, W.D.; Bender, S.; Meier, K.; Thode, L.E.; Watson, J.M.

    1989-01-01

    The 10-/mu/m Los Alamos free-electron laser (FEL) facility is being upgraded. The conventional electron gun and bunchers have been replaced with a much more compact 6-MeV photoinjector accelerator. By adding existing parts from previous experiments, the primary beam energy will be doubled to 40 MeV. With the existing 1-m wiggler (/lambda//sub w/ = 2.7 cm) and resonator, the facility can produce photons with wavelengths from 3 to 100 /mu/m when lasing on the fundamental mode and produce photons in the visible spectrum with short-period wigglers or harmonic operation. After installation of a 150/degree/ bend, a second wiggler will be added as an amplifier. The installation of laser transport tubes between the accelerator vault and an upstairs laboratory will provide experimenters with a radiation-free environment for experiments. Although the initial experimental program of the upgraded facility will be to test the single accelerator-master oscillator/power amplifier configuration, some portion of the operational time of the facility can be dedicated to user experiments. 13 refs., 5 figs., 6 tabs.

  16. Investigations and Recommendations on the Use of Existing Experiments in Criticality Safety Analysis of Nuclear Fuel Cycle Facilities for Weapons-Grade Plutonium

    SciTech Connect

    Rearden, B.T.

    2002-05-29

    Sensitivity and Uncertainty (S/U) methods, recently developed at Oak Ridge National Laboratory (ORNL) have been demonstrated to determine the applicability of critical benchmark experiments to the criticality code validation of design systems. These methods, although still under development, have been recently published in several sources. Development of the techniques used in this report was conducted through joint support from the United States Department of Energy (U.S. DOE) and the Nuclear Regulatory Commission (NRC) to provide a physics-based approach for the establishment of the area of applicability of critical experiments per the requirements of ANSI/ANS-8.1. Use of these methods may allow users to interpolate and extrapolate the traditional area of applicability (AOA) of a given set of critical experiments to include new application areas that may not have been anticipated during the experiment design. The new S/U analytical tools include the SEN1 and SEN3 sensitivity analysis sequences, which will be available with the next release of the Standardized Computer Analyses for Licensing Evaluation (SCALE) code system. These analysis sequences compute the relative change in the system neutron multiplication factor, k{sub eff}, which would be observed for perturbations in the group-wise neutron cross-section data for each reaction of each nuclide in the system. The CANDE code uses sensitivity data determined separately for the design system applications and the individual experiments, along with the cross-section-covariance data, to calculate integral parameters which give a measure of the similarity between a particular design system and an experimental benchmark. A high-valued integral parameter for an experiment application pair indicates that the experiment demonstrates similar properties to the application. Thus, the experiment is applicable for the criticality code validation of the design system. A theoretical basis for the S/U techniques applied in this

  17. Portable MRI developed at Los Alamos

    SciTech Connect

    Espy, Michelle

    2015-04-22

    Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are

  18. Los Alamos experiments on the few nucleon systems

    SciTech Connect

    Spinka, H.

    1986-01-01

    A summary of recently studied proton-, pion-, and neutron-induced reactions on nuclei up to /sup 4/He at LAMPF is given. Upgrades to the LAMPF experimental facilities for these studies are described. Some new proton-proton total cross sections in pure helicity states (..delta..sigma/sub L/(pp)) from the ZGS near 3 GeV/c are also presented. 46 refs., 4 figs.

  19. Students' Critical Mathematical Thinking Skills and Character: Experiments for Junior High School Students through Realistic Mathematics Education Culture-Based

    ERIC Educational Resources Information Center

    Palinussa, Anderson L.

    2013-01-01

    This paper presents the findings of a quasi-experimental with pre-test-post-test design and control group that aims to assess students' critical mathematical thinking skills and character through realistic mathematics education (RME) culture-based. Subjects of this study were 106 junior high school students from two low and medium schools level in…

  20. The Discourse of Parent Involvement in Special Education: A Critical Analysis Linking Policy Documents to the Experiences of Mothers

    ERIC Educational Resources Information Center

    Lai, Yuan; Vadeboncoeur, Jennifer A.

    2013-01-01

    Parent involvement is acknowledged as a crucial aspect of the education of students with special needs. However, the discourse of parent involvement represents parent involvement in limited ways, thereby controlling how and the extent to which parents can be involved in the education of their children. In this article, critical discourse analysis…

  1. Environmental surveillance at Los Alamos during 1979

    SciTech Connect

    Not Available

    1980-04-01

    This report documents the environmental surveillance program conducted by the Los Alamos Scientific Laboratory (LASL) in 1979. Routine monitoring for radiation and radioactive or chemical substances was conducted on the Laboratory site and in the surrounding region to determine compliance with appropriate standards and permit early identification of possible undesirable trends. Results and interpretation of the data for 1979 on penetrating radiation, chemical and radiochemical quality of ambient air, surface and ground water, municipal water supply, soils and sediments, food, and airborne and liquid effluents are included. Comparisons with appropriate standards and regulations or with background levels from natural or other non-LASL sources provide a basis for concluding that environmental effects attributable to LASL operations are minor and cannot be considered likely to result in any hazard to the population of the area. Results of several special studies provide documentation of some unique environmental conditions in the LASL environs.

  2. Environmental surveillance at Los Alamos during 1992

    SciTech Connect

    Kohen, K.; Stoker, A.; Stone, G.

    1994-07-01

    This report describes the environmental surveillance program at Los Alamos National Laboratory during 1992. The Laboratory routinely monitors for radiation and for radioactive and nonradioactive materials at (or on) Laboratory sites as well as in the surrounding region. LANL uses the monitoring results to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1992 to assess external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Using comparisons with standards, regulations, and background levels, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, laboratory employees, or the environment.

  3. Foreign National Involvement at Los Alamos

    NASA Astrophysics Data System (ADS)

    Wilhelmy, Jerry

    2000-04-01

    Since the beginning of the spring of 1999 there has been an intense national media focus on alleged security breaches by a foreign born scientist employed at LANL. Alarmed by an apparent growing sense of xenophobia, the Fellows of the Los Alamos National Laboratory addressed this issue by preparing a white paper on Foreign National Involvement at LANL (www.fellows.lanl.gov). Its purpose was to recognize and acknowledge the vital role that foreign scientists have played and continue to play in making LANL a forefront scientific institution. This legacy will be discussed, as well as concerns that constraining regulations triggered by this episode and subsequent reactions to this by our scientific peer community could have long term consequences on the vitality of the Laboratory.

  4. Environmental surveillance at Los Alamos during 1989

    SciTech Connect

    Not Available

    1990-12-01

    This report describes the environmental surveillance program conducted by Los Alamos National Laboratory during 1989. Routine monitoring for radiation and radioactive or chemical materials is conducted on the Laboratory site as well as in the surrounding region. Monitoring results are used to determine compliance with appropriate standards and to permit early identification of potentially undesirable trends. Results and interpretation of data for 1989 cover external penetrating radiation; quantities of airborne emissions and effluents; concentrations of chemicals and radionuclides in ambient air, surface and ground waters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Comparisons with appropriate standards, regulations, and background levels provide the basis for concluding that environmental effects from Laboratory operations are small and do not pose a threat to the public, Laboratory employees, or the environment. 58 refs., 31 figs., 39 tabs.

  5. Environmental surveillance at Los Alamos during 1995

    SciTech Connect

    1996-10-01

    This report describes the environmental surveillance program at Los Alamos National Laboratory (LANL or the Laboratory) during 1995. The Laboratory routinely monitors for radiation and for radioactive and nonradioactive materials at (or on) Laboratory sites as well as in the surrounding region. LANL uses the monitoring result to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1995 to assess external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Using comparisons with standards, regulations, and background levels, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, Laboratory employees, or the environment.

  6. Environmental surveillance at Los Alamos during 1987

    SciTech Connect

    Not Available

    1988-05-01

    This report describes the environmental surveillance program conducted by Los Alamos National Laboratory during 1987. Routine monitoring for radiation and radioactive or chemical materials is conducted on the Laboratory site as well as in the surrounding region. Monitoring results are used to determine compliance with appropriate standards and to permit early identification of potentially undesirable trends. Results and interpretation of data for 1987 cover: external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface and ground waters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Comparisons with appropriate standards, regulations, and background levels provide the basis for concluding that environmental effects from Laboratory operations are insignificant and do not pose a threat to the public, Laboratory employees, or the environment. 113 refs., 33 figs., 120 tabs.

  7. Los Alamos National Laboratory transuranic database analysis

    SciTech Connect

    Christensen, D.V.; Rogers, P.S.Z.; Kosiewicz, S.T.; LeBrun, D.B.

    1997-02-01

    This paper represents an overview of analyses conducted on the TRU database maintained by the Los Alamos National Laboratory (LANL). This evaluation was conducted to support the ``TRU Waste Workoff Strategies`` document and provides an estimation of the waste volume that potentially could be certified and ready for shipment to (WIPP) in April of 1998. Criteria defined in the WIPP WAC, including container type, weight limits, plutonium fissile gram equivalents and decay heat, were used to evaluated the waste for compliance. LANL evaluated the containers by facility and by waste stream to determining the most efficient plan for characterization and certification of the waste. Evaluation of the waste presently in storage suggested that 40- 60% potentially meets the WIPP WAC Rev. 5 criteria.

  8. Explorer at Los Alamos: A library for the future

    SciTech Connect

    Waters, M.; McDonald, J.

    1998-03-01

    Since 1993, Los Alamos National Laboratory, has been developing World Wide Web (WWW) applications to facilitate access to vast quantities of information critical to the successful operation of a nuclear weapons facility Explorer is a web-based tool that integrates full-text search and retrieval technology, custom user in interface faces, user-friendly navigation tools, extremely large document collections, and data collection and workflow applications. Explorer`s first major thrust was to enable quick access to regulatory and policy information used by Department of Energy facilities throughout the country. Today, Explorer users can easily search document collections containing, millions of pages of information scattered across Web sites around the country. Over fifteen large applications containing multiple collections are searchable through Explorer, and the subject areas range from DOE regulations to quality management-related resources to technology transfer opportunities. Explorer has succeeded because it provides quick and easy access to stored data across the Web; it saves time and reduces costs in comparison with traditional information distribution, access, and retrieval methods.

  9. Environmental analysis of Lower Pueblo/Lower Los Alamos Canyon, Los Alamos, New Mexico

    SciTech Connect

    Ferenbaugh, R.W.; Buhl, T.E.; Stoker, A.K.; Becker, N.M.; Rodgers, J.C.; Hansen, W.R.

    1994-12-01

    The radiological survey of the former radioactive waste treatment plant site (TA-45), Acid Canyon, Pueblo Canyon, and Los Alamos Canyon found residual contamination at the site itself and in the channel and banks of Acid, Pueblo, and lower Los Alamos Canyons all the way to the Rio Grande. The largest reservoir of residual radioactivity is in lower Pueblo Canyon, which is on DOE property. However, residual radioactivity does not exceed proposed cleanup criteria in either lower Pueblo or lower Los Alamos Canyons. The three alternatives proposed are (1) to take no action, (2) to construct a sediment trap in lower Pueblo Canyon to prevent further transport of residual radioactivity onto San Ildefonso Indian Pueblo land, and (3) to clean the residual radioactivity from the canyon system. Alternative 2, to cleanup the canyon system, is rejected as a viable alternative. Thousands of truckloads of sediment would have to be removed and disposed of, and this effort is unwarranted by the low levels of contamination present. Residual radioactivity levels, under either present conditions or projected future conditions, will not result in significant radiation doses to persons exposed. Modeling efforts show that future transport activity will not result in any residual radioactivity concentrations higher than those already existing. Thus, although construction of a sediment trap in lower Pueblo Canyon is a viable alternative, this effort also is unwarranted, and the no-action alternative is the preferred alternative.

  10. Environmental surveillance at Los Alamos during 2008

    SciTech Connect

    Fuehne, David; Gallagher, Pat; Hjeresen, Denny; Isaacson, John; Johson, Scot; Morgan, Terry; Paulson, David; Rogers, David

    2009-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) Environmental Programs Directorate, as required by US Department of Energy Order 450.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2007. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, air; Chapters 5 and 6, water and sediments; Chapter 7, soils; and Chapter 8, foodstuffs and biota) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory’s technical areas and their associated programs, and Appendix D provides web links to more information.

  11. Environmental surveillance at Los Alamos during 2005

    SciTech Connect

    2006-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (LANL or the Laboratory) environmental organization, as required by US Department of Energy Order 5400.1, General Environmental Protection Program, and US Department of Energy Order 231.IA, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory's efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory's major environmental programs. Chapter 2 reports the Laboratory's compliance status for 2005. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, Air; Chapters 5 and 6, Water and Sediments; Chapter 7, Soils; and Chapter 8, Foodstuffs and Biota) in a format to meet the needs of a general and scientific audience. Chapter 9, new for this year, provides a summary of the status of environmental restoration work around LANL. A glossary and a list ofacronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory's technical areas and their associated programs, and Appendix D provides web links to more information.

  12. Environmental surveillance at Los Alamos during 2009

    SciTech Connect

    Fuehne, David; Poff, Ben; Hjeresen, Denny; Isaacson, John; Johnson, Scot; Morgan, Terry; Paulson, David; Salzman, Sonja; Rogers, David

    2010-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) environmental organization, as required by US Department of Energy Order 5400.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2009. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (air in Chapter 4; water and sediments in Chapters 5 and 6; soils in Chapter 7; and foodstuffs and biota in Chapter 8) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. The new Chapter 10 describes the Laboratory’s environmental stewardship efforts and provides an overview of the health of the Rio Grande. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory’s technical

  13. Integrating Safety with Science,Technology and Innovation at Los Alamos National Laboratory

    SciTech Connect

    Rich, Bethany M

    2012-04-02

    The mission of Los Alamos National Laboratory (LANL) is to develop and apply science, technology and engineering solutions to ensure the safety, security, and reliability of the U.S. nuclear deterrent; reduce global threats; and solve emerging national security challenges. The most important responsibility is to direct and conduct efforts to meet the mission with an emphasis on safety, security, and quality. In this article, LANL Environmental, Safety, and Health (ESH) trainers discuss how their application and use of a kinetic learning module (learn by doing) with a unique fall arrest system is helping to address one the most common industrial safety challenges: slips and falls. A unique integration of Human Performance Improvement (HPI), Behavior Based Safety (BBS) and elements of the Voluntary Protection Program (VPP) combined with an interactive simulator experience is being used to address slip and fall events at Los Alamos.

  14. An Analysis of a Counselor Education Program with a Critical Examination of Practicum and Group Experiences. Final Report.

    ERIC Educational Resources Information Center

    Anderson, Sharon

    Part I of this two-part study compared prospective counselors' scores on selected measuring instruments at the beginning of their course work and practicum experience, and later at the end of their practicum experience. Part II examined the effect of a course in group counseling techniques on prospective counselors' self concepts, self images,…

  15. Final Progress Report: Internship at Los Alamos National Laboratory

    SciTech Connect

    Dunham, Ryan Q.

    2012-08-10

    Originally I was tasked fluidized bed modeling, however, I changed projects. While still working with ANSYS Fluent, I performed a study of particle tracks in glove boxes. This is useful from a Health-Physics perspective, dealing respirable particles that can be hazardous to the human body. I iteratively tested different amounts of turbulent particles in a steady-state flow. The goal of this testing was to discover how Fluent handles built-in Rosin-Rammler distributions for particle injections. I worked on the health physics flow problems and distribution analysis under the direction of two mentors, Bruce Letellier and Dave Decroix. I set up and ran particle injection calculations using Fluent. I tried different combinations of input parameters to produce sets of 500,000, 1 million, and 1.5 million particles to determine what a good test case would be for future experiments. I performed a variety of tasks in my work as an Undergraduate Student Intern at LANL this summer, and learned how to use a powerful CFD application in addition to expanding my skills in MATLAB. I enjoyed my work at LANL and hope to be able to use the experience here to further my career in the future working in a security-conscious environment. My mentors provided guidance and help with all of my projects and I am grateful for the opportunity to work at Los Alamos National Laboratory.

  16. Alternate measurements of benefit to criticality issues at Hanford

    SciTech Connect

    Toffer, H.; Cabrilla, D.E.

    1997-06-01

    Measurements in a critical mass facility, such as the Los Alamos Critical Experiments Facility, could be performed on simulated nuclear waste materials that would provide important critical mass information and concurrently provide a calibration of alternate measurement techniques. In addition to criticality information, the measurements could also provide a better assessment of diluent material/neutron interaction cross sections. An Hanford, large quantities of fissionable materials are dispersed in tanks, fuel storage pools, and in solid waste. Although the fissionable materials are well diluted by a variety of neutron-moderating and -absorbing substances, it is difficult to assess the margin of subcriticality. A number of measurement approaches are proposed that will either help determine fissionable material concentrations, distributions, or provide a direct measure of subcriticality. The methods under consideration involve passive neutron counting, active neutron measurements, pulse neutron applications, neutron noise analyses, and cover gas evaluations. Active neutron measurements can also provide insight into the determination of neutron absorber concentrations. Efforts are underway to test some of the methods in actual waste tank environments and geometries. It is important that these methods be tested and calibrated in a critical mass facility.

  17. Discovering the nature of advanced nursing practice in high dependency care: a critical care nurse consultant's experience.

    PubMed

    Fairley, Debra

    2005-06-01

    This paper describes how a critical care nurse consultant's clinical role has evolved within a surgical high dependency unit (SHDU) in a large teaching hospitals trust. In order to provide some background to role development, an overview of the research exploring the nature of advanced nursing practice in the context of critical care will be presented. From the outset, advanced nursing practice was not perceived as the acquisition and application of technical procedures usually undertaken by doctors, but possibly an integration of medicine and nursing where holistic nursing assessment is combined with symptom-focused physical examination. A reflective account of practical problems encountered relating to role integration, professional autonomy, legal and consent issues, non-medical prescribing, and role evaluation will be presented. A model of working that can be applied to high dependency units, integrating the role of the advanced nurse practitioner within the clinical team, will be described. PMID:15907666

  18. Critical care nurses' experiences caring for the casualties of war evacuated from the front line: lessons learned and needs identified.

    PubMed

    Kenny, Deborah J; Hull, Mary S

    2008-03-01

    Nursing in a critical care environment is stressful, particularly when patients are young, previously healthy soldiers who have experienced multiple severe, life-threatening injuries. These injuries not only devastate the injured soldiers and their families, but also significantly impact the nurses caring for these patients. This article discusses some stressors identified by critical care nurses in two military medical treatment facilities where the most severely injured soldiers undergo definitive care, and examines the evolution of the concept of compassion fatigue, its symptoms, and methods of coping. Examples of how the nurses currently working with these young soldiers manage their own stressors are discussed and suggestions for successful coping strategies are provided. PMID:18206583

  19. 2015 Los Alamos Space Weather Summer School Research Reports

    SciTech Connect

    Cowee, Misa; Chen, Yuxi; Desai, Ravindra; Hassan, Ehab; Kalmoni, Nadine; Lin, Dong; Depascuale, Sebastian; Hughes, Randall Scott; Zhou, Hong

    2015-11-24

    The fifth Los Alamos Space Weather Summer School was held June 1st - July 24th, 2015, at Los Alamos National Laboratory (LANL). With renewed support from the Institute of Geophysics, Planetary Physics, and Signatures (IGPPS) and additional support from the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) Office of Science, we hosted a new class of five students from various U.S. and foreign research institutions. The summer school curriculum includes a series of structured lectures as well as mentored research and practicum opportunities. Lecture topics including general and specialized topics in the field of space weather were given by a number of researchers affiliated with LANL. Students were given the opportunity to engage in research projects through a mentored practicum experience. Each student works with one or more LANL-affiliated mentors to execute a collaborative research project, typically linked with a larger ongoing research effort at LANL and/or the student’s PhD thesis research. This model provides a valuable learning experience for the student while developing the opportunity for future collaboration. This report includes a summary of the research efforts fostered and facilitated by the Space Weather Summer School. These reports should be viewed as work-in-progress as the short session typically only offers sufficient time for preliminary results. At the close of the summer school session, students present a summary of their research efforts. Titles of the papers included in this report are as follows: Full particle-in-cell (PIC) simulation of whistler wave generation, Hybrid simulations of the right-hand ion cyclotron anisotropy instability in a sub-Alfvénic plasma flow, A statistical ensemble for solar wind measurements, Observations and models of substorm injection dispersion patterns, Heavy ion effects on Kelvin-Helmholtz instability: hybrid study, Simulating plasmaspheric electron densities with a two

  20. Limited-scope probabilistic safety analysis for the Los Alamos Meson Physics Facility (LAMPF)

    SciTech Connect

    Sharirli, M.; Rand, J.L.; Sasser, M.K.; Gallegos, F.R.

    1992-01-01

    The reliability of instrumentation and safety systems is a major issue in the operation of accelerator facilities. A probabilistic safety analysis was performed or the key safety and instrumentation systems at the Los Alamos Meson Physics Facility (LAMPF). in Phase I of this unique study, the Personnel Safety System (PSS) and the Current Limiters (XLs) were analyzed through the use of the fault tree analyses, failure modes and effects analysis, and criticality analysis. Phase II of the program was done to update and reevaluate the safety systems after the Phase I recommendations were implemented. This paper provides a brief review of the studies involved in Phases I and II of the program.

  1. [Experience of extracorporeal membrane oxygenation in critical care of respiratory failure in newborn with congenital diaphragmatic hernia in perinatal center].

    PubMed

    Burov, A A; Nikiforov, D V; Podurovskaia, Iu L; Dorofeeva, E I; Abramian, M A; Makhalin, M V; Shatalov, K V; Nikiforov, V S; Degtiarev, D N

    2013-01-01

    The article deals with an experience of veno-arterial extracorporeal membrane oxygenation use in preterm infants with congenital diaphragmatic hernia during postoperative period in the perinatal center. PMID:24749262

  2. Integral Reactor Physics Benchmarks - the International Criticality Safety Benchmark Evaluation Project (icsbep) and the International Reactor Physics Experiment Evaluation Project (irphep)

    NASA Astrophysics Data System (ADS)

    Briggs, J. Blair; Nigg, David W.; Sartori, Enrico

    2006-04-01

    Since the beginning of the nuclear industry, thousands of integral experiments related to reactor physics and criticality safety have been performed. Many of these experiments can be used as benchmarks for validation of calculational techniques and improvements to nuclear data. However, many were performed in direct support of operations and thus were not performed with a high degree of quality assurance and were not well documented. For years, common validation practice included the tedious process of researching integral experiment data scattered throughout journals, transactions, reports, and logbooks. Two projects have been established to help streamline the validation process and preserve valuable integral data: the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP). The two projects are closely coordinated to avoid duplication of effort and to leverage limited resources to achieve a common goal. A short history of these two projects and their common purpose are discussed in this paper. Accomplishments of the ICSBEP are highlighted and the future of the two projects outlined.

  3. Micrometer-sized ice particles for planetary-science experiments - I. Preparation, critical rolling friction force, and specific surface energy

    NASA Astrophysics Data System (ADS)

    Gundlach, B.; Kilias, S.; Beitz, E.; Blum, J.

    2011-08-01

    Coagulation models assume a higher sticking threshold for micrometer-sized ice particles than for micrometer-sized silicate particles. However, in contrast to silicates, laboratory investigations of the collision properties of micrometer-sized ice particles (in particular, of the most abundant H 2O-ice) have not been conducted yet. Thus, we used two different experimental methods to produce micrometer-sized H 2O-ice particles, i.e. by spraying H 2O droplets into liquid nitrogen and by spraying H 2O droplets into a cold nitrogen atmosphere. The mean particle radii of the ice particles produced with these experimental methods are (1.49 ± 0.79) μm and (1.45 ± 0.65) μm. Ice aggregates composed of the micrometer-sized ice particles are highly porous (volume filling factor: ϕ = 0.11 ± 0.01) or rather compact (volume filling factor: ϕ = 0.72 ± 0.04), depending on the method of production. Furthermore, the critical rolling friction force of FRoll, ice = (114.8 ± 23.8) × 10 -10 N was measured for micrometer-sized ice particles, which exceeds the critical rolling friction force of micrometer-sized SiO 2 particles (F=(12.1±3.6)×10-10N). This result implies that the adhesive bonding between micrometer-sized ice particles is stronger than the bonding strength between SiO 2 particles. An estimation of the specific surface energy of micrometer-sized ice particles, derived from the measured critical rolling friction forces and the surface energy of micrometer-sized SiO 2 particles, results in γice = 0.190 J m -2.

  4. Assessment of TRAC-PF1/MOD1 version 14. 3 using separate effects critical flow and blowdown experiments

    SciTech Connect

    Spindler, B.; Pellissier, M. )

    1990-01-01

    Independent assessment of the TRAC code was conducted at the Centre d'Etudes Nucleaires de Grenoble of the Commissariate a l'Energie Atomique (France) in the frame of the ICAP. This report presents the results of the assessment of TRAC-PF1/MOD1 version 14.3 using critical flow steady state tests (MOBY-DICK, SUPER-MOBY-DICK), and blowdown tests (CANON, SUPER-CANON, VERTICAL-CANON, MARVIKEN, OMEGA-TUBE, OMEGA-BUNDLE). This document, Volume 1, presents the text and tables from this assessment.

  5. Assessment of TRAC-PF1/MOD1 Version 14. 3 using separate effects critical flow and blowdown experiments

    SciTech Connect

    Spindler, B.; Pellissier, M. )

    1990-01-01

    Independent assessment of the TRAC code was conducted at the Centre d'Etudes Nucleaires de Grenoble of the Commissariate a l'Energie Atomique (France) in the frame of the ICAP. This report presents the results of the assessment of TRAC-PF1/MOD1 version 14.3 using critical flow steady state tests (MOBY-DICK, SUPER-MOBY-DICK), and blowdown tests (CANON, SUPER-CANON, VERTICAL-CANON, MARVIKEN, OMEGA-TUBE, OMEGA-BUNDLE). This document, Volume 2, presents the experimental data and figures from the assessment.

  6. The Prompt Fission Neutron Spectrum: From Experiment to the Evaluated Data and its Impact on Critical Assemblies

    SciTech Connect

    Rising, Michael Evan

    2015-06-10

    After a brief introduction concerning nuclear data, prompt fission neutron spectrum (PFNS) evaluations and the limited PFNS covariance data in the ENDF/B-VII library, and the important fact that cross section uncertainties ~ PFNS uncertainties, the author presents background information on the PFNS (experimental data, theoretical models, data evaluation, uncertainty quantification) and discusses the impact on certain well-known critical assemblies with regard to integral quantities, sensitivity analysis, and uncertainty propagation. He sketches recent and ongoing research and concludes with some final thoughts.

  7. A study of the perception and experiences of critical care nurses in caring for potential and actual organ donors: implications for nurse education.

    PubMed

    Watkinson, G E

    1995-11-01

    This paper describes a research study designed to explore the knowledge, perceptions and attitudes of practising critical care nurses towards caring for 'brain stem dead' cadaver organ donors and their families. The influence of formal nurse education and experiential learning were investigated together with what nurses felt could better prepare them for this role. Data were collected through self-completion questionnaires from 103 critical care nurses. This was instrumental in forming a semi-structured interview schedule whereby seven respondents were interviewed. The findings of the study suggest that nurses are very favourable towards organ donation and this correlated with their knowledge of brain stem death (P < 0.024). Nurses with between 6 and 10 years critical care experience had a significantly higher knowledge base (P < 0.05) than those of less or greater experience. Nevertheless, when challenged some nurses were less comfortable with the concept of brain stem death and caring for these patients. A degree of cognitive dissonance was identified. Discussion revealed that all nurses need to have a better understanding of their role in organ donation, no mater what nursing discipline they practice. This may help to expel some of the myths that have, undeservedly, become established and given the donor process a rather sinister image. PMID:8568068

  8. Development and validation of a critical gradient energetic particle driven Alfven eigenmode transport model for DIII-D tilted neutral beam experiments

    NASA Astrophysics Data System (ADS)

    Waltz, R. E.; Bass, E. M.; Heidbrink, W. W.; VanZeeland, M. A.

    2015-11-01

    Recent experiments with the DIII-D tilted neutral beam injection (NBI) varying the beam energetic particle (EP) source profiles have provided strong evidence that unstable Alfven eigenmodes (AE) drive stiff EP transport at a critical EP density gradient [Heidbrink et al 2013 Nucl. Fusion 53 093006]. Here the critical gradient is identified by the local AE growth rate being equal to the local ITG/TEM growth rate at the same low toroidal mode number. The growth rates are taken from the gyrokinetic code GYRO. Simulation show that the slowing down beam-like EP distribution has a slightly lower critical gradient than the Maxwellian. The ALPHA EP density transport code [Waltz and Bass 2014 Nucl. Fusion 54 104006], used to validate the model, combines the low-n stiff EP critical density gradient AE mid-core transport with the Angioni et al (2009 Nucl. Fusion 49 055013) energy independent high-n ITG/TEM density transport model controling the central core EP density profile. For the on-axis NBI heated DIII-D shot 146102, while the net loss to the edge is small, about half the birth fast ions are transported from the central core r/a  <  0.5 and the central density is about half the slowing down density. These results are in good agreement with experimental fast ion pressure profiles inferred from MSE constrained EFIT equilibria.

  9. New Developments in Proton Radiography at the Los Alamos Neutron Science Center (LANSCE)

    SciTech Connect

    Morris, C. L.; Brown, E. N.; Agee, C.; Bernert, T.; Bourke, M. A. M.; Burkett, M. W.; Buttler, W. T.; Byler, D. D.; Chen, C. F.; Clarke, A. J.; Cooley, J. C.; Gibbs, P. J.; Imhoff, S. D.; Jones, R.; Kwiatkowski, K.; Mariam, F. G.; Merrill, F. E.; Murray, M. M.; Olinger, C. T.; Oro, D. M.; Nedrow, P.; Saunders, A.; Terrones, G.; Trouw, F.; Tupa, D.; Vogan, W.; Winkler, B.; Wang, Z.; Zellner, M. B.

    2015-12-30

    An application of nuclear physics, a facility for using protons for flash radiography, was developed at the Los Alamos Neutron Science Center (LANSCE). Protons have proven far superior to high energy x-rays for flash radiography because of their long mean free path, good position resolution, and low scatter background. Although this facility is primarily used for studying very fast phenomena such as high explosive driven experiments, it is finding increasing application to other fields, such as tomography of static objects, phase changes in materials and the dynamics of chemical reactions. The advantages of protons are discussed, data from some recent experiments will be reviewed and concepts for new techniques are introduced.

  10. Rotational symmetry breaking in the topological superconductor SrxBi2Se3 probed by upper-critical field experiments

    PubMed Central

    Pan, Y.; Nikitin, A. M.; Araizi, G. K.; Huang, Y. K.; Matsushita, Y.; Naka, T.; de Visser, A.

    2016-01-01

    Recently it was demonstrated that Sr intercalation provides a new route to induce superconductivity in the topological insulator Bi2Se3. Topological superconductors are predicted to be unconventional with an odd-parity pairing symmetry. An adequate probe to test for unconventional superconductivity is the upper critical field, Bc2. For a standard BCS layered superconductor Bc2 shows an anisotropy when the magnetic field is applied parallel and perpendicular to the layers, but is isotropic when the field is rotated in the plane of the layers. Here we report measurements of the upper critical field of superconducting SrxBi2Se3 crystals (Tc = 3.0 K). Surprisingly, field-angle dependent magnetotransport measurements reveal a large anisotropy of Bc2 when the magnet field is rotated in the basal plane. The large two-fold anisotropy, while six-fold is anticipated, cannot be explained with the Ginzburg-Landau anisotropic effective mass model or flux flow induced by the Lorentz force. The rotational symmetry breaking of Bc2 indicates unconventional superconductivity with odd-parity spin-triplet Cooper pairs (Δ4-pairing) recently proposed for rhombohedral topological superconductors, or might have a structural nature, such as self-organized stripe ordering of Sr atoms. PMID:27350295

  11. Rotational symmetry breaking in the topological superconductor SrxBi2Se3 probed by upper-critical field experiments.

    PubMed

    Pan, Y; Nikitin, A M; Araizi, G K; Huang, Y K; Matsushita, Y; Naka, T; de Visser, A

    2016-01-01

    Recently it was demonstrated that Sr intercalation provides a new route to induce superconductivity in the topological insulator Bi2Se3. Topological superconductors are predicted to be unconventional with an odd-parity pairing symmetry. An adequate probe to test for unconventional superconductivity is the upper critical field, Bc2. For a standard BCS layered superconductor Bc2 shows an anisotropy when the magnetic field is applied parallel and perpendicular to the layers, but is isotropic when the field is rotated in the plane of the layers. Here we report measurements of the upper critical field of superconducting SrxBi2Se3 crystals (Tc = 3.0 K). Surprisingly, field-angle dependent magnetotransport measurements reveal a large anisotropy of Bc2 when the magnet field is rotated in the basal plane. The large two-fold anisotropy, while six-fold is anticipated, cannot be explained with the Ginzburg-Landau anisotropic effective mass model or flux flow induced by the Lorentz force. The rotational symmetry breaking of Bc2 indicates unconventional superconductivity with odd-parity spin-triplet Cooper pairs (Δ4-pairing) recently proposed for rhombohedral topological superconductors, or might have a structural nature, such as self-organized stripe ordering of Sr atoms. PMID:27350295

  12. A design of experiments test to define critical spray cleaning parameters for Brulin 815 GD and Jettacin cleaners

    NASA Technical Reports Server (NTRS)

    Keen, Jill M.; Evans, Kurt B.; Schiffman, Robert L.; Deweese, C. Darrell; Prince, Michael E.

    1995-01-01

    Experimental design testing was conducted to identify critical parameters of an aqueous spray process intended for cleaning solid rocket motor metal components (steel and aluminum). A two-level, six-parameter, fractional factorial matrix was constructed and conducted for two cleaners, Brulin 815 GD and Diversey Jettacin. The matrix parameters included cleaner temperature and concentration, wash density, wash pressure, rinse pressure, and dishwasher type. Other spray parameters: nozzle stand-off, rinse water temperature, wash and rinse time, dry conditions, and type of rinse water (deionized) were held constant. Matrix response testing utilized discriminating bond specimens (fracture energy and tensile adhesion strength) which represent critical production bond lines. Overall, Jettacin spray cleaning was insensitive to the range of conditions tested for all parameters and exhibited bond strengths significantly above the TCA test baseline for all bond lines tested. Brulin 815 was sensitive to cleaning temperature, but produced bond strengths above the TCA test baseline even at the lower temperatures. Ultimately, the experimental design database was utilized to recommend process parameter settings for future aqueous spray cleaning characterization work.

  13. Critical Heat Flux Phenomena at HighPressure & Low Mass Fluxes: NEUP Final Report Part I: Experiments

    SciTech Connect

    Corradini, Michael; Wu, Qiao

    2015-04-30

    This report is a preliminary document presenting an overview of the Critical Heat Flux (CHF) phenomenon, the High Pressure Critical Heat Flux facility (HPCHF), preliminary CHF data acquired, and the future direction of the research. The HPCHF facility has been designed and built to study CHF at high pressure and low mass flux ranges in a rod bundle prototypical of conceptual Small Modular Reactor (SMR) designs. The rod bundle is comprised of four electrically heated rods in a 2x2 square rod bundle with a prototypic chopped-cosine axial power profile and equipped with thermocouples at various axial and circumferential positions embedded in each rod for CHF detection. Experimental test parameters for CHF detection range from pressures of ~80 – 160 bar, mass fluxes of ~400 – 1500 kg/m2s, and inlet water subcooling from ~30 – 70°C. The preliminary data base established will be further extended in the future along with comparisons to existing CHF correlations, models, etc. whose application ranges may be applicable to the conditions of SMRs.

  14. Establishing a Wild, Ex Situ Population of a Critically Endangered Shade-Tolerant Rainforest Conifer: A Translocation Experiment.

    PubMed

    Zimmer, Heidi C; Offord, Catherine A; Auld, Tony D; Baker, Patrick J

    2016-01-01

    Translocation can reduce extinction risk by increasing population size and geographic range, and is increasingly being used in the management of rare and threatened plant species. A critical determinant of successful plant establishment is light environment. Wollemia nobilis (Wollemi pine) is a critically endangered conifer, with a wild population of 83 mature trees and a highly restricted distribution of less than 10 km2. We used under-planting to establish a population of W. nobilis in a new rainforest site. Because its optimal establishment conditions were unknown, we conducted an experimental translocation, planting in a range of different light conditions from deeply shaded to high light gaps. Two years after the experimental translocation, 85% of plants had survived. There were two distinct responses: very high survival (94%) but very low growth, and lower survival (69%) and higher growth, associated with initial plant condition. Overall survival of translocated W. nobilis was strongly increased in planting sites with higher light, in contrast to previous studies demonstrating long-term survival of wild W. nobilis juveniles in deep shade. Translocation by under-planting may be useful in establishing new populations of shade-tolerant plant species, not least by utilizing the range of light conditions that occur in forest understories. PMID:27403527

  15. Establishing a Wild, Ex Situ Population of a Critically Endangered Shade-Tolerant Rainforest Conifer: A Translocation Experiment

    PubMed Central

    Zimmer, Heidi C.; Offord, Catherine A.; Auld, Tony D.; Baker, Patrick J.

    2016-01-01

    Translocation can reduce extinction risk by increasing population size and geographic range, and is increasingly being used in the management of rare and threatened plant species. A critical determinant of successful plant establishment is light environment. Wollemia nobilis (Wollemi pine) is a critically endangered conifer, with a wild population of 83 mature trees and a highly restricted distribution of less than 10 km2. We used under-planting to establish a population of W. nobilis in a new rainforest site. Because its optimal establishment conditions were unknown, we conducted an experimental translocation, planting in a range of different light conditions from deeply shaded to high light gaps. Two years after the experimental translocation, 85% of plants had survived. There were two distinct responses: very high survival (94%) but very low growth, and lower survival (69%) and higher growth, associated with initial plant condition. Overall survival of translocated W. nobilis was strongly increased in planting sites with higher light, in contrast to previous studies demonstrating long-term survival of wild W. nobilis juveniles in deep shade. Translocation by under-planting may be useful in establishing new populations of shade-tolerant plant species, not least by utilizing the range of light conditions that occur in forest understories. PMID:27403527

  16. Review of liquid metal heat pipe work at Los Alamos

    SciTech Connect

    Reid, R.S.; Merrigan, M.A.; Sena, J.T.

    1990-01-01

    A survey of space-power related liquid metal heat pipe work at Los Alamos National Laboratory is presented. Heat pipe development at Los Alamos has been on-going since 1963. Heat pipes were initially developed for thermionic nuclear-electrical power production in space. Since then Los Alamos has developed liquid metal heat pipes for numerous applications related to high temperature systems in both the space and terrestrial environments. Some of these applications include thermionic electrical generators, thermoelectric energy conversion (both in-core and direct radiation), thermal energy storage, hypersonic vehicle leading edge cooling, and heat pipe vapor laser cells. Some of the work performed at Los Alamos has been documented in internal reports that are often little-known. A representative description and summary of progress in space-related liquid metal heat pipe technology is provided followed by a reference section citing sources where these works may be found. 53 refs.

  17. Explosive Flux Compression: 50 Years of Los Alamos Activities

    SciTech Connect

    Fowler, C.M.; Thomson, D.B.; Garn, W.B.

    1998-10-18

    Los Alamos flux compression activities are surveyed, mainly through references in view of space limitations. However, two plasma physics programs done with Sandia National Laboratory are discussed in more detail.

  18. Environmental Surveillance at Los Alamos during 2007

    SciTech Connect

    2008-09-30

    Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) Environmental Directorate, as required by US Department of Energy Order 450.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and near the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2007. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, air; Chapters 5 and 6, water and sediments; Chapter 7, soils; and Chapter 8, foodstuffs and biota) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the laboratory’s technical areas and their associated programs, and Appendix D provides web links to more information. In printed copies of this report or Executive Summary, we have

  19. A complexity basis for phenomenology: How information states at criticality offer a new approach to understanding experience of self, being and time.

    PubMed

    Hankey, Alex

    2015-12-01

    In the late 19th century Husserl studied our internal sense of time passing, maintaining that its deep connections into experience represent prima facie evidence for it as the basis for all investigations in the sciences: Phenomenology was born. Merleau-Ponty focused on perception pointing out that any theory of experience must accord with established aspects of biology i.e. be embodied. Recent analyses suggest that theories of experience require non-reductive, integrative information, together with a specific property connecting them to experience. Here we elucidate a new class of information states with just such properties found at the loci of control of complex biological systems, including nervous systems. Complexity biology concerns states satisfying self-organized criticality. Such states are located at critical instabilities, commonly observed in biological systems, and thought to maximize information diversity and processing, and hence to optimize regulation. Major results for biology follow: why organisms have unusually low entropies; and why they are not merely mechanical. Criticality states form singular self-observing systems, which reduce wave packets by processes of perfect self-observation associated with feedback gain g = 1. Analysis of their information properties leads to identification of a new kind of information state with high levels of internal coherence, and feedback loops integrated into their structure. The major idea presented here is that the integrated feedback loops are responsible for our 'sense of self', and also the feeling of continuity in our sense of time passing. Long-range internal correlations guarantee a unique kind of non-reductive, integrative information structure enabling such states to naturally support phenomenal experience. Being founded in complexity biology, they are 'embodied'; they also fulfill the statement that 'The self is a process', a singular process. High internal correlations and René Thom

  20. [Experience with knowledge development in food handlers with te implementation of Hazard Analysis Critical control points (HACCP) in a hospital food service].

    PubMed

    de Sousa, A A; de Salles, R K; Felipe, M R; Tosin, I

    1999-03-01

    The present article has as objective to describe the methodology of an experience of implantation of Hazard Analyses Critical Control Points (HACCP) with food handlers in a hospital food service establishment, inside of a conception of relationship and construction of knowledge. Meetings with the food handlers and nutritionists, with the objective of raising the difficulties poined for the sector and the work to be developed. The HACCP consisted of the evaluation of the operations, following the sequential steps recommended, looking itself to instruct the food handlers on the methods of the operations and its interpretations. The detected critical points, the measures of control, the criteria of correction and the monitoring have widely been argued, serving as didactic elements for the reconstruction of quality of the preparations. The discussions generated actions that were developed in short term, revealing the need of a more effective and continuous partnership for the new proposals. PMID:10412507

  1. The moral experience of parents regarding life-support decisions for their critically-ill children: a preliminary study in France.

    PubMed

    Carnevale, Franco A; Canouï, Pierre; Hubert, Philippe; Farrell, Catherine; Leclerc, Francis; Doussau, Amélie; Seguin, Marie-Josée; Lacroix, Jacques

    2006-03-01

    The common paediatric critical care practice in France is for physicians (rather than parents) to maintain the ultimate responsibility for lifesupport decisions in children. Some French literature asserts that it is inappropriate for parents to bear such responsibilities because they do not have the required knowledge and should be protected from feeling culpable for such decisions. The aim of this grounded theory preliminary study was to examine the moral experience of parents of critically-ill children that required life-support decisions in France. A convenience purposive sample of seven parents was recruited in Paris. Five principal themes emerged as significant from these interviews: (1) a need for more information; (2) physicians should be responsible for life-support decisions; (3) the child's concerns and wishes need to be better heard; (4) maternal guilt; and (5) physicians require better training in parent communication. These findings raise important issues for clinical practice and further research in France. PMID:16464934

  2. Conducting Multi-Generational Qualitative Research in Education: An Experiment in Grounded Theory. Black Studies and Critical Thinking. Volume 5

    ERIC Educational Resources Information Center

    Collins, Donald R.

    2011-01-01

    This book outlines a methodology for viewing multiple generations of African Americans, specifically those who were called or called themselves Negro, Colored, Black, or African American (NCBAA). Within this framework, African Americans of varying ages describe their lives and educational experiences, allowing researchers to address a variety of…

  3. Unpacking Your Study Abroad Experience: Critical Reflection for Workplace Competencies. Volume 1, Issue 1. CERI Research Brief 1-2008

    ERIC Educational Resources Information Center

    Gardner, Phil; Gross, Linda; Steglitz, Inge

    2008-01-01

    Colleges and universities are in competition to claim leadership in preparing students for a global world through participation in international experiences. Michigan State University (MSU) is often recognized as one of the leaders in study abroad, having woven the ethos of global education tightly into the core fabric of the university and…

  4. Worldviews, Criticisms, and the Peer Circle: A Study of the Experiences of a Student Teacher in an Overseas School

    ERIC Educational Resources Information Center

    Karaman, A. Cendel; Tochon, Francois V.

    2010-01-01

    This article explores international student teaching (IST) within the narratives of a prospective language teacher from the midwestern region of the United States. With a focus on one participant, the case study highlights significant factors that relate to the IST experience in Ecuador. A corpus generated from verbal protocols collected over a…

  5. Growth and Expansion of the International Criticality Safety Benchmark Evaluation Project and the Newly Organized International Reactor Physics Experiment Evaluation Project

    SciTech Connect

    J. Blair Briggs; Lori Scott; Yolanda Rugama; Enrico Satori

    2007-05-01

    Since ICNC 2003, the International Criticality Safety Benchmark Evaluation Project (ICSBEP) has continued to expand its efforts and broaden its scope. Criticality-alarm / shielding type benchmarks and fundamental physics measurements that are relevant to criticality safety applications are not only included in the scope of the project, but benchmark data are also included in the latest version of the handbook. A considerable number of improvements have been made to the searchable database, DICE and the criticality-alarm / shielding benchmarks and fundamental physics measurements have been included in the database. There were 12 countries participating on the ICSBEP in 2003. That number has increased to 18 with recent contributions of data and/or resources from Brazil, Czech Republic, Poland, India, Canada, and China. South Africa, Germany, Argentina, and Australia have been invited to participate. Since ICNC 2003, the contents of the “International Handbook of Evaluated Criticality Safety Benchmark Experiments” have increased from 350 evaluations (28,000 pages) containing benchmark specifications for 3070 critical or subcritical configurations to 442 evaluations (over 38,000 pages) containing benchmark specifications for 3957 critical or subcritical configurations, 23 criticality-alarm-placement / shielding configurations with multiple dose points for each, and 20 configurations that have been categorized as fundamental physics measurements that are relevant to criticality safety applications in the 2006 Edition of the ICSBEP Handbook. Approximately 30 new evaluations and 250 additional configurations are expected to be added to the 2007 Edition of the Handbook. Since ICNC 2003, a reactor physics counterpart to the ICSBEP, The International Reactor Physics Experiment Evaluation Project (IRPhEP) was initiated. Beginning in 1999, the IRPhEP was conducted as a pilot activity by the by the Organization of Economic Cooperation and Development (OECD) Nuclear Energy

  6. Los Alamos low-level waste performance assessment status

    SciTech Connect

    Wenzel, W.J.; Purtymun, W.D.; Dewart, J.M.; Rodgers, J.E.

    1986-06-01

    This report reviews the documented Los Alamos studies done to assess the containment of buried hazardous wastes. Five sections logically present the environmental studies, operational source terms, transport pathways, environmental dosimetry, and computer model development and use. This review gives a general picture of the Los Alamos solid waste disposal and liquid effluent sites and is intended for technical readers with waste management and environmental science backgrounds but without a detailed familiarization with Los Alamos. The review begins with a wide perspective on environmental studies at Los Alamos. Hydrology, geology, and meteorology are described for the site and region. The ongoing Laboratory-wide environmental surveillance and waste management environmental studies are presented. The next section describes the waste disposal sites and summarizes the current source terms for these sites. Hazardous chemical wastes and liquid effluents are also addressed by describing the sites and canyons that are impacted. The review then focuses on the transport pathways addressed mainly in reports by Healy and Formerly Utilized Sites Remedial Action Program. Once the source terms and potential transport pathways are described, the dose assessment methods are addressed. Three major studies, the waste alternatives, Hansen and Rogers, and the Pantex Environmental Impact Statement, contributed to the current Los Alamos dose assessment methodology. Finally, the current Los Alamos groundwater, surface water, and environmental assessment models for these mesa top and canyon sites are described.

  7. Electron clearing in the Los Alamos Proton Storage Ring

    SciTech Connect

    Plum, M.A.; Allen, J.; Borden, M.J.; Fitzgerald, D.H.; Macek, R.J.; Wang, T.S.

    1995-05-01

    The instability observed in the Los Alamos Proton Storage Ring (PSR) has been tentatively identified as an electron-proton instability. A source of electrons must exist for this instability to occur. The PSR injection section contains the stripper foil, and therefore provides several strong sources of electrons. An electron clearing system was installed in the injection section to clear out these electrons. The system comprised: (1) a foil biasing system to clear the SEM and thermionic electrons, (2) a pair of low-field bending magnets with a Faraday cup to clear the convoy electrons, and (3) two pairs of clearing electrodes, one upstream and one downstream of the stripper foil, to clear the remaining electrons. This paper discusses the design and performance of the Electron Clearing System, and its effect on the instability. Also presented are some results from other charge-collection experiments that suggest there is also substantial electron production in parts of the ring other than the injection section.

  8. The CIV processes in the CRIT experiments. [reconciliation of Critical Ionization Velocity hypothesis with sounding rocket observations

    NASA Technical Reports Server (NTRS)

    Papadopoulos, K.

    1992-01-01

    A qualitative analysis is conducted to reconcile the experimental data from critical ionization velocity (CIV) studies with CIV theories. The experimental data are reviewed demonstrating that: (1) the wave frequency is variable and low; (2) the wave polarization is almost isotropic; (3) electron energization is not easily reconciled with the observed wave spectrum; and (4) ambient electron density plays a role in determining CIV triggering conditions. Analytical treatment is given to the dispersion relation of the lower hybrid wave (LWH) instability driven by the streaming of an ion beam generated by the interaction of the neutral cloud with the ambient atmosphere. By incorporating the LWH instabilities of strong turbulence and finite-size effects into theoretical CIV relationships, the observations can be interpreted. The issues raised by the experimental data are understood within the context of a hypothesis of backward propagating nonlinearly collapsing wavepackets.

  9. Frank A. Beach award: programming of neuroendocrine function by early-life experience: a critical role for the immune system.

    PubMed

    Bilbo, Staci D

    2013-05-01

    Many neuropsychiatric disorders are associated with a strong dysregulation of the immune system, and several have a striking etiology in development as well. Our recent evidence using a rodent model of neonatal Escherichia coli infection has revealed novel insight into the mechanisms underlying cognitive deficits in adulthood, and suggests that the early-life immune history of an individual may be critical to understanding the relative risk of developing later-life mental health disorders in humans. A single neonatal infection programs the function of immune cells within the brain, called microglia, for the life of the rodent such that an adult immune challenge results in exaggerated cytokine production within the brain and associated cognitive deficits. I describe the important role of the immune system, notably microglia, during brain development, and discuss some of the many ways in which immune activation during early brain development can affect the later-life outcomes of neural function, immune function, and cognition. PMID:23474365

  10. Experience Of A US Air Force Surgical And Critical Care Team Deployed In Support Of Special Operations Command Africa.

    PubMed

    Delmonaco, Brian L; Baker, Aaron; Clay, Jared; Kilbourn, James

    2016-01-01

    An eight-person team of conventional US Air Force (USAF) medical providers deployed to support US Special Operations Forces (SOF) in North and West Africa for the first time in November 2014. The predeployment training, operations while deployed, and lessons learned from the challenges of performing surgery and medical evacuations in the remote desert environment of Chad and Niger on the continent of Africa are described. The vast area of operations and far-forward posture of these teams requires cooperation between partner African nations, the French military, and SOF to make these medical teams effective providers of surgical and critical care in Africa. The continuous deployment of conventional USAF medical providers since 2014 in support of US Special Operations Command Africa is challenging and will benefit from more medical teams and effective air assets to provide casualty evacuation across the vast area of operations. PMID:27045506

  11. Expanded recycling at Los Alamos National Laboratory

    SciTech Connect

    Betschart, J.F.; Malinauskas, L.; Burns, M.

    1996-07-01

    The Pollution Prevention Program Office has increased recycling activities, reuse, and options to reduce the solid waste streams through streamlining efforts that applied best management practices. The program has prioritized efforts based on volume and economic considerations and has greatly increased Los Alamos National Laboratory`s (LANL`s) recycle volumes. The Pollution Prevention Program established and chairs a Solid Waste Management Solutions Group to specifically address and solve problems in nonradioactive, Resource Conservation and Recovery Act (RCRA), state-regulated, and sanitary and industrial waste streams (henceforth referred to as sanitary waste in this paper). By identifying materials with recycling potential, identifying best management practices and pathways to return materials for reuse, and introducing the concept and practice of {open_quotes}asset management,{open_quotes} the Group will divert much of the current waste stream from disposal. This Group is developing procedures, agreements, and contracts to stage, collect, sort, segregate, transport and process materials, and is also garnering support for the program through the involvement of upper management, facility managers, and generators.

  12. Saving Water at Los Alamos National Laboratory

    SciTech Connect

    Erickson, Andy

    2015-03-16

    Los Alamos National Laboratory decreased its water usage by 26 percent in 2014, with about one-third of the reduction attributable to using reclaimed water to cool a supercomputing center. The Laboratory's goal during 2014 was to use only re-purposed water to support the mission at the Strategic Computing Complex. Using reclaimed water from the Sanitary Effluent Reclamation Facility, or SERF, substantially decreased water usage and supported the overall mission. SERF collects industrial wastewater and treats it for reuse. The reclamation facility contributed more than 27 million gallons of re-purposed water to the Laboratory's computing center, a secured supercomputing facility that supports the Laboratory’s national security mission and is one of the institution’s larger water users. In addition to the strategic water reuse program at SERF, the Laboratory reduced water use in 2014 by focusing conservation efforts on areas that use the most water, upgrading to water-conserving fixtures, and repairing leaks identified in a biennial survey.

  13. Cultural competence in psychosocial and psychiatric care: a critical perspective with reference to research and clinical experiences in California, US and in Germany.

    PubMed

    Schultz, Dagmar

    2004-01-01

    The impact of culture and ethnicity on the diagnosis and treatment of patients with mental disorders has been of growing interest and concern to professionals in the United States and also in Germany. This contribution intends to give an overview of key aspects regarding competence in intercultural situations using research and clinical experiences from the United States and from Germany. The issue of racism and discrimination as contributing factors in the development of mental disorders will be critically examined from a US and a German perspective. PMID:15774394

  14. Uranium systems to enhance benchmarks for use in the verification of criticality safety computer models. Final report, February 16, 1990--December 31, 1994

    SciTech Connect

    Busch, R.D.

    1995-02-24

    Dr. Robert Busch of the Department of Chemical and Nuclear Engineering was the principal investigator on this project with technical direction provided by the staff in the Nuclear Criticality Safety Group at Los Alamos. During the period of the contract, he had a number of graduate and undergraduate students working on subtasks. The objective of this work was to develop information on uranium systems to enhance benchmarks for use in the verification of criticality safety computer models. During the first year of this project, most of the work was focused on setting up the SUN SPARC-1 Workstation and acquiring the literature which described the critical experiments. By august 1990, the Workstation was operational with the current version of TWODANT loaded on the system. MCNP, version 4 tape was made available from Los Alamos late in 1990. Various documents were acquired which provide the initial descriptions of the critical experiments under consideration as benchmarks. The next four years were spent working on various benchmark projects. A number of publications and presentations were made on this material. These are briefly discussed in this report.

  15. Extending the benefits of early mobility to critically ill patients undergoing continuous renal replacement therapy: the Michigan experience.

    PubMed

    Talley, Cheryl L; Wonnacott, Robert O; Schuette, Janice K; Jamieson, Jill; Heung, Michael

    2013-01-01

    Evidence to support improved outcomes with early ambulation is strong in medical literature. Yet, critically ill continuous renal replacement therapy (CRRT) patients remain tethered to their beds by devices delivering supportive therapy. The University of Michigan Adult CRRT Committee identified this deficiency and sought to change it. There was no guidance in the literature to support mobilizing this population; therefore, we reviewed literature from devices with similar technological profiles. Revision of our institutional mobility protocol for the CRRT population included a simple safety acronym, ASK. The acronym addresses appropriate candidacy; secured, appropriate access; and potential device and patient complications as a memorable aid to help nursing staff determine whether their CRRT patients are candidates for early mobility. After implementing our CRRT mobility standard, a preliminary study of 109 CRRT patients and a review of incident reports related to CRRT demonstrated no significant adverse patient events or falls and no access complications related to mobility. This deliberate intervention allows CRRT patients to safely engage in mobility activities to improve this population's outcomes. A simple mobility protocol and safety acronym partnered with strong clinical leadership has permitted the University of Michigan to add CRRT patients to the body of early mobility literature. PMID:23221445

  16. The path from art to evidence in treating critical limb ischaemia--reflections on 35 years' experience.

    PubMed

    Lepäntalo, M

    2012-01-01

    Despite numerous attempts, chronic critical limb ischaemia (CLI) has not been unequivocally defined as yet. Its epidemiology is poorly investigated and its prevalence probably higher than anticipated. It is accompanied by high mortality and morbidity irrespective of the way it is treated. Its management is very expensive. Additionally, the prevailing diabetes epidemic is increasing the need for revascularizations although there is a clear lack of evidence as to when to revascularize an ulcerated diabetic foot. The fast development of endovascular techniques blurs the vision as the window of opportunity for gathering proper evidence keeps narrowing. The notion of endovascular artistry prevails, but attempts to conduct proper studies with clear definitions, strict criteria and appropriate outcome measures in a standardised manner should continue--preferably using propensity scoring if randomised controlled trials are not possible. This review highlights some of the steps leading from art to evidence and illustrates the difficulties encountered along the path. In parallel with this overview, the progress of the treatment for CLI in Finland is described from the perspective of the work concluded at Helsinki University Central Hospital. PMID:22623439

  17. Group Dynamics as a Critical Component of Successful Space Exploration: Conceptual Theory and Insights from the Biosphere 2 Closure Experiment

    NASA Astrophysics Data System (ADS)

    Nelson, Mark; Allen, John P.

    As space exploration and eventually habitation achieves longer durations, successfully managing group dynamics of small, physically isolated groups will become vital. The paper summarizes important underlying research and conceptual theory and how these manifested in a well-documented example: the closure experiments of Biosphere 2. Key research breakthroughs in discerning the operation of small human groups comes from the pioneering work of W.R. Bion. He discovered two competing modalities of behavior. The first is the “task-oriented” or work group governed by shared acceptance of goals, reality-thinking in relation to time, resources and rational, and intelligent management of challenges presented. The opposing, usually unconscious, modality is what Bion called the “basic-assumption” group and alternates between three “group animal” groups: dependency/kill the leader; fight/flight and pairing. If not dealt with, these dynamics work to undermine and defeat the conscious task group’s goal achievement. The paper discusses crew training and selection, various approaches to structuring the work and hierarchy of the group, the importance of contact with a larger population through electronic communication and dealing with the “us-them” syndrome frequently observed between crew and Mission Control. The experience of the first two year closure of Biosphere 2 is drawn on in new ways to illustrate vicissitudes and management of group dynamics especially as both the inside team of biospherians and key members of Mission Control had training in working with group dynamics. Insights from that experience may help mission planning so that future groups in space cope successfully with inherent group dynamics challenges that arise.

  18. Using formal specification in the Guidance and Control Software (GCS) experiment. Formal design and verification technology for life critical systems

    NASA Technical Reports Server (NTRS)

    Weber, Doug; Jamsek, Damir

    1994-01-01

    The goal of this task was to investigate how formal methods could be incorporated into a software engineering process for flight-control systems under DO-178B and to demonstrate that process by developing a formal specification for NASA's Guidance and Controls Software (GCS) Experiment. GCS is software to control the descent of a spacecraft onto a planet's surface. The GCS example is simplified from a real example spacecraft, but exhibits the characteristics of realistic spacecraft control software. The formal specification is written in Larch.

  19. Nuclear criticality safety: 5-day training course

    SciTech Connect

    Schlesser, J.A.

    1992-11-01

    This compilation of notes is presented as a source reference for the criticality safety course. It represents the contributions of many people, particularly Tom McLaughlin, the course's primary instructor. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used at Los Alamos; be able to identify examples of circumstances present during criticality accidents; be able to identify examples of computer codes used by the nuclear criticality safety specialist; be able to identify examples of safety consciousness required in nuclear criticality safety.

  20. Nuclear criticality safety: 5-day training course

    SciTech Connect

    Schlesser, J.A.

    1992-11-01

    This compilation of notes is presented as a source reference for the criticality safety course. It represents the contributions of many people, particularly Tom McLaughlin, the course`s primary instructor. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used at Los Alamos; be able to identify examples of circumstances present during criticality accidents; be able to identify examples of computer codes used by the nuclear criticality safety specialist; be able to identify examples of safety consciousness required in nuclear criticality safety.