Science.gov

Sample records for critical loading configurations

  1. CRITICAL LOADS METHODS

    EPA Science Inventory

    I summarize the results of an interagency project that 1) defines a generic approach to quantifying and reporting critical loads, and 2) exercises that generic approach by examining a data rich system -- the critical loads of sulfur deposition and it's effect on the chronic acidi...

  2. Azo dye load-shock on relative behavior of biofilm and suspended growth configured periodic discontinuous batch mode operations: critical evaluation with enzymatic and bio-electrocatalytic analysis.

    PubMed

    Naresh Kumar, A; Nagendranatha Reddy, C; Hari Prasad, R; Venkata Mohan, S

    2014-09-01

    Effect of dye (C.I.Acid Black 10B) load-shock was comparatively evaluated in biofilm (self-immobilized) and suspended growth systems operated in periodic discontinuous batch mode (PDBR, anoxic-aerobic-anoxic) was investigated. At higher dye load (1250 mg dye/l), biofilm system showed relatively higher dye (74.5%) and COD (46%) removal efficiencies than the corresponding suspended mode operation (dye/COD removal efficiency, 42%/65%). Increment in dye load showed increment in azo reductase and dehydrogenase enzyme activities. Voltammograms (cyclic) showed higher reduction currents (RC) with increment in dye load specifically in biofilm system. Derivative cyclic voltammograms analysis depicted the involvement of mediators (NAD (+), FAD(+), etc.) which presumably played a major role in electron transport chain and dye degradation. Disappearance of peak (1612 cm(-1)) specific to azo group in FTIR spectrum, at higher loading rate in both the systems indicates the non-inhibitory and robust nature of PDBR operation. PMID:24859232

  3. Compensator configurations for load currents' symmetrization

    NASA Astrophysics Data System (ADS)

    Rusinaru, D.; Manescu, L. G.; Dinu, R. C.

    2016-02-01

    This paper approaches aspects regarding the mitigation effects of asymmetries in 3-phase 3-wire networks. The measure consisting in connecting of load current symmetrization devices at the load coupling point is presented. A time-variation of compensators parameters is determined as a function of the time-recorded electrical values. The general sizing principle of the load current symmetrization reactive components is based on a simple equivalent model of the unbalanced 3-phase loads. By using these compensators a certain control of the power components transits is ensured in the network. The control is based on the variations laws of the compensators parameters as functions of the recorded electrical values: [B] = [T]·[M]. The link between compensator parameters and measured values is ensured by a transformation matrix [T] for each operation conditions of the supply network. Additional conditions for improving of energy and efficiency performance of the compensator are considered: i.e. reactive power compensation. The compensator sizing algorithm was implemented into a MATLAB environment software, which generate the time-evolution of the parameters of load current symmetrization device. The input data of application takes into account time-recording of the electrical values. By using the compensator sizing software, some results were achieved for the case of a consumer connected at 20 kV busbar of a distribution substation, during 24 hours measurement session. Even the sizing of the compensators aimed some additional network operation aspects (power factor correction) correlated with the total or major load symmetrizations, the harmonics aspects of the network values were neglected.

  4. Initial dynamic load estimates during configuration design

    NASA Technical Reports Server (NTRS)

    Schiff, Daniel

    1987-01-01

    This analysis includes the structural response to shock and vibration and evaluates the maximum deflections and material stresses and the potential for the occurrence of elastic instability, fatigue and fracture. The required computations are often performed by means of finite element analysis (FEA) computer programs in which the structure is simulated by a finite element model which may contain thousands of elements. The formulation of a finite element model can be time consuming, and substantial additional modeling effort may be necessary if the structure requires significant changes after initial analysis. Rapid methods for obtaining rough estimates of the structural response to shock and vibration are presented for the purpose of providing guidance during the initial mechanical design configuration stage.

  5. Inductrack III configuration--a maglev system for high loads

    DOEpatents

    Post, Richard F

    2013-11-12

    Inductrack III configurations are suited for use in transporting heavy freight loads. Inductrack III addresses a problem associated with the cantilevered track of the Inductrack II configuration. The use of a cantilevered track could present mechanical design problems in attempting to achieve a strong enough track system such that it would be capable of supporting very heavy loads. In Inductrack III, the levitating portion of the track can be supported uniformly from below, as the levitating Halbach array used on the moving vehicle is a single-sided one, thus does not require the cantilevered track as employed in Inductrack II.

  6. Inductrack III configuration--a maglev system for high loads

    DOEpatents

    Post, Richard F

    2015-03-24

    Inductrack III configurations are suited for use in transporting heavy freight loads. Inductrack III addresses a problem associated with the cantilevered track of the Inductrack II configuration. The use of a cantilevered track could present mechanical design problems in attempting to achieve a strong enough track system such that it would be capable of supporting very heavy loads. In Inductrack III, the levitating portion of the track can be supported uniformly from below, as the levitating Halbach array used on the moving vehicle is a single-sided one, thus does not require the cantilevered track as employed in Inductrack II.

  7. Acoustic-loads research for powered-lift configurations

    NASA Technical Reports Server (NTRS)

    Schoenster, J. A.; Willis, C. M.; Schroeder, J. C.; Mixson, J. S.

    1976-01-01

    Data presented from large-scale model tests with jet engines having thrusts of 9 kN (2000 lb) and 36 kN (8000 lb) include acoustic loads for an externally blown wing and flap induced by a TF34 jet engine, an upper surface blown (USB) aircraft model in a wind tunnel, and two USB models in static tests. Comparisons of these results with results from acoustic loads studies on configurations of other sizes are made and the implications of these results on interior noise and acoustic fatigue are discussed.

  8. Loading configurations and driving mechanisms for joints based on the Griffith energy-balance concept

    NASA Astrophysics Data System (ADS)

    Engelder, Terry; Fischer, Mark P.

    1996-05-01

    Using the Griffith energy-balance concept to model joint propagation in the brittle crust, two laboratory loading configurations serve as appropriate analogs for in situ conditions: the dead-weight load and the fixed-grips load. The distinction between these loading configurations is based largely on whether or not a loaded boundary moves as a joint grows. During displacement of a loaded boundary, the energy necessary for joint propagation comes from work by the dead weight (i.e., a remote stress). When the loaded boundary remains stationary, as if held by rigid grips, the energy for joint propagation develops upon release of elastic strain energy within the rock mass. These two generic loading configurations serve as models for four common natural loading configurations: a joint-normal load; a thermoelastic load; a fluid load; and an axial load. Each loading configuration triggers a different joint-driving mechanism, each of which is the release of energy through elastic strain and/or work. The four mechanisms for energy release are joint-normal stretching, elastic contraction, poroelastic contraction under either a constant fluid drive or fluid decompression, and axial shortening, respectively. Geological circumstances favoring each of the joint-driving mechanisms are as follows. The release of work under joint-normal stretching occurs whenever layer-parallel extension keeps pace with slow or subcritical joint propagation. Under fixed grips, a substantial crack-normal tensile stress can accumulate by thermoelastic contraction until joint propagation is driven by the release of elastic strain energy. Within the Earth the rate of joint propagation dictates which of these two driving mechanisms operates, with faster propagation driven by release of strain energy. Like a dead-weight load acting to separate the joint walls, pore fluid exerts a traction on the interior of some joints. Joint propagation under fluid loading may be driven by a release of elastic strain

  9. The critical shear load of rectangular plates

    NASA Technical Reports Server (NTRS)

    Seydel, Edgar

    1933-01-01

    This report gives formulas for analyzing the critical shear load of a simply supported square, isotropic (simple flat plate), or orthogonal anisotropic plate (a plate in which the rigidity in two directions perpendicular to each other is different, i.e. plywood or corrugated sheet), these formulas, although arrived at by approximation method, seem to agree fairly well with experimental results.

  10. Critical Configurations of Hard Disks on the Torus

    Energy Science and Technology Software Center (ESTSC)

    2013-04-16

    CCHDT constructs and classifies various arrangements of hard disks of a single radius places on the unit square with periodic boundary conditions. Specifially, a given configuration is evolved to the nearest critical point on a smoothed hard disk energy fuction, and is classified by the adjacency matrix of the canonically labelled contact graph.

  11. Configuration and Sizing of a Test Fixture for Panels Under Combined Loads

    NASA Technical Reports Server (NTRS)

    Lovejoy, Andrew E.

    2006-01-01

    Future air and space structures are expected to utilize composite panels that are subjected to combined mechanical loads, such as bi-axial compression/tension, shear and pressure. Therefore, the ability to accurately predict the buckling and strength failures of such panels is important. While computational analysis can provide tremendous insight into panel response, experimental results are necessary to verify predicted performances of these panels to judge the accuracy of computational methods. However, application of combined loads is an extremely difficult task due to the complex test fixtures and set-up required. Presented herein is a comparison of several test set-ups capable of testing panels under combined loads. Configurations compared include a D-box, a segmented cylinder and a single panel set-up. The study primarily focuses on the preliminary sizing of a single panel test configuration capable of testing flat panels under combined in-plane mechanical loads. This single panel set-up appears to be best suited to the testing of both strength critical and buckling critical panels. Required actuator loads and strokes are provided for various square, flat panels.

  12. Configuration selection study for isolated loads using parabolic dish modules

    NASA Technical Reports Server (NTRS)

    Revere, W.; Bowyer, J.; Fujita, T.; Awaya, H.

    1981-01-01

    A configuration tradeoff study has been conducted to determine optimum solar thermal parabolic dish power systems for isolated load applications. The specific application of an essentially constant power demand as required for MX missile shelters is treated. Supplying a continuous level of power with high reliability is shown to require a power system comprising modular parabolic dish power units where the heat engines of the modular power units can be driven by fossil fuels as well as solar-derived heat. Since constraints on reliability result in the provision of a power generating capability that exceeds the constant demand level, efficient utilization of the power system requires battery storage. Tradeoffs regarding the optimum size of storage are investigated as a function of the number of power modules and the cost of the fossil fuel which is used to meet the demand when insolation is unavailable and storage is depleted.

  13. Configuration selection study for isolated loads using parabolic dish modules

    NASA Technical Reports Server (NTRS)

    Revere, W.; Bowyer, J.; Fujita, T.; Awaya, H.

    1982-01-01

    A configuration tradeoff study was conducted to determine optimum solar thermal parabolic dish power systems for isolated load applications. The specific application of an essentially constant power demand as required for MX missile shelters is treated. Supplying a continuous level of power with high reliability is shown to require a power system comprising modular parabolic dish power units where the heat engines of the modular power units can be driven by fossil fuels as well as solar-derived heat. Since constraints on reliability result in the provision of a power generating capability that exceeds the constant demand level, efficient utilization of the power system requires battery storage. Tradeoffs regarding the optimum size of storage are investigated as a function of the number of power modules and the cost of the fossil fuel.

  14. Silicon Nitride Creep Under Various Specimen-Loading Configurations

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Holland, Frederic A.

    2000-01-01

    Extensive creep testing of a hot-pressed silicon nitride (NC 132) was performed at 1300 C in air using five different specimen-loading configurations: (1) pure tension, (2) pure compression, (3) four-point uniaxial flexure, (4) ball-on-ring biaxial flexure, and (5) ring-on-ring biaxial flexure. This paper reports experimental results as well as test techniques developed in this work. Nominal creep strain and its rate for a given nominal applied stress were greatest in tension, least in compression, and intermediate in uniaxial and biaxial flexure. Except for the case of compression loading, nominal creep strain generally decreased with time, resulting in a less-defined steady-state condition. Of the four creep formulations-power-law, hyperbolic sine, step, and redistribution--the conventional power-law formulation still provides the most convenient and reasonable estimation of the creep parameters of the NC 132 material. The data base to be obtained will be used to validate the NASA Glenn-developed design code CARES/Creep (ceramics analysis and reliability evaluation of structures and creep).

  15. Critical load and buckling of the single pile foundation subjected to the vertical load

    NASA Astrophysics Data System (ADS)

    Ma, Jianjun; Peng, Jian; Wang, Lianhua; Zhao, Yueyu

    2013-07-01

    In this study, the critical load and buckling of the single pile foundation subjected to the vertical load are investigated. Considering the second-order moment of the soil-structure interaction, the refined model of the single pile foundation is derived. Then, the critical load and buckling phenomenon of the single pile foundation is examined. Moreover, the effects of the vertical load and the foundation parameters on the critical load and buckling of the single pile foundation are systematically investigated.

  16. Criticality Benchmark Analysis of the HTTR Annular Startup Core Configurations

    SciTech Connect

    John D. Bess

    2009-11-01

    One of the high priority benchmarking activities for corroborating the Next Generation Nuclear Plant (NGNP) Project and Very High Temperature Reactor (VHTR) Program is evaluation of Japan's existing High Temperature Engineering Test Reactor (HTTR). The HTTR is a 30 MWt engineering test reactor utilizing graphite moderation, helium coolant, and prismatic TRISO fuel. A large amount of critical reactor physics data is available for validation efforts of High Temperature Gas-cooled Reactors (HTGRs). Previous international reactor physics benchmarking activities provided a collation of mixed results that inaccurately predicted actual experimental performance.1 Reevaluations were performed by the Japanese to reduce the discrepancy between actual and computationally-determined critical configurations.2-3 Current efforts at the Idaho National Laboratory (INL) involve development of reactor physics benchmark models in conjunction with the International Reactor Physics Experiment Evaluation Project (IRPhEP) for use with verification and validation methods in the VHTR Program. Annular cores demonstrate inherent safety characteristics that are of interest in developing future HTGRs.

  17. Photovoltaic power converter system with a controller configured to actively compensate load harmonics

    DOEpatents

    de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

    2008-12-16

    Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

  18. On Critical Buckling Loads of Columns under End Load Dependent on Direction

    PubMed Central

    Başbük, Musa; Eryılmaz, Aytekin; Atay, M. Tarık

    2014-01-01

    Most of the phenomena of various fields of applied sciences are nonlinear problems. Recently, various types of analytical approximate solution techniques were introduced and successfully applied to the nonlinear differential equations. One of the aforementioned techniques is the Homotopy analysis method (HAM). In this study, we applied HAM to find critical buckling load of a column under end load dependent on direction. We obtained the critical buckling loads and compared them with the exact analytic solutions in the literature. PMID:27379303

  19. Cognitive Load for Configuration Comprehension in Computer-Supported Geometry Problem Solving: An Eye Movement Perspective

    ERIC Educational Resources Information Center

    Lin, John Jr-Hung; Lin, Sunny S. J.

    2014-01-01

    The present study investigated (a) whether the perceived cognitive load was different when geometry problems with various levels of configuration comprehension were solved and (b) whether eye movements in comprehending geometry problems showed sources of cognitive loads. In the first investigation, three characteristics of geometry configurations…

  20. Critical top tension for static equilibrium configuration of a steel catenary riser

    NASA Astrophysics Data System (ADS)

    Athisakul, Chainarong; Klaycham, Karun; Chucheepsakul, Somchai

    2014-12-01

    This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser (SCR) by using the finite element method. The critical top tension is the minimum top tension that can maintain the equilibrium of the SCR. If the top tension is smaller than the critical value, the equilibrium of the SCR does not exist. If the top tension is larger than the critical value, there are two possible equilibrium configurations. These two configurations exhibit the nonlinear large displacement. The configuration with the smaller displacement is stable, while the one with larger displacement is unstable. The numerical results show that the increases in the riser's vertical distances, horizontal offsets, riser's weights, internal flow velocities, and current velocities increase the critical top tensions of the SCR. In addition, the parametric studies are also performed in order to investigate the limit states for the analysis and design of the SCR.

  1. Explosive Welding of Tubular Configurated Joints for Critical Applications

    NASA Technical Reports Server (NTRS)

    Hardwick, R.

    1985-01-01

    Explosive welding can provide the answer to problems of permanently joining metals typically used in the aerospace industry. The explosive bonding process is a solid state bonding process enabling material incompatibility problems associated with fusion welding to be overcome. In addition, heat affected zones are eliminated thus, enhancing joint strength, properties and performance. The process requires the parts being joined to be impelled, by means of explosives, to collide with each other. Certain critical collision parameters must be met and controlled and these parameters are defined. Various component geometries which satisfy the collision parameters are described. Examples of transition joints used in the aerospace industry are described and illustrated.

  2. Geometrical aspects of critical Ising configurations in two dimensions

    NASA Astrophysics Data System (ADS)

    Blöte, H. W. J.; Knops, Y. M. M.; Nienhuis, B.

    1992-06-01

    We present a physical interpretation of a number of exotic exponents of the two-dimensional Ising model, i.e., exponents that do have a conformal classification, but outside the unitary grid. They describe the scaling behavior of geometric properties of Ising and random clusters. For instance, the probability that two spins at a distance r lie on the perimeter of the same Ising cluster decays as r-5/4 at criticality. These results are obtained via mappings on the Coulomb gas. A part of the Coulomb gas scenario is verified by means of finite-size scaling of transfer-matrix results.

  3. Improved critical current in confined superconductors in parallel field configuration

    NASA Astrophysics Data System (ADS)

    Glatz, Andreas; Aronson, Igor; Wang, Yonglei; Xiao, Zhili

    2015-03-01

    We present results on the re-entrance of the superconducting state in systems placed into a magnetic field parallel to the applied current. In experiments it was observed that the magneto-resistance first increases with magnetic field, but at higher field drops again such that superconductivity is recovered. This effect is strongly temperature dependent and can lead to a suppression of resistance below the measurable threshold over a range of a few kG. We study the vortex dynamics and magneto-resistance in this situation in the framework of a large-scale time-dependent Ginzburg Landau simulation. A small external current as well as the magnetic field are applied in the x-direction, the latter is then ramped up. Our simulations reproduce this effect and reveal the mechanism for the observed behavior: the intermediate resistive state is due to a vortex instability leading to an unwinding of twisted vortex configurations. This leads to a periodic dynamic resistive state. When the field increases these instabilities get stabilized due to a higher vortex density and the resistance drops upon increasing the magnetic field. Work was supported by the Scientific Discovery through Advanced Computing (SciDAC) program funded by U.S. Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences, and by the Office of Science, Materials Sc.

  4. Loads analysis and testing of flight configuration solid rocket motor outer boot ring segments

    NASA Technical Reports Server (NTRS)

    Ahmed, Rafiq

    1990-01-01

    The loads testing on in-house-fabricated flight configuration Solid Rocket Motor (SRM) outer boot ring segments. The tests determined the bending strength and bending stiffness of these beams and showed that they compared well with the hand analysis. The bending stiffness test results compared very well with the finite element data.

  5. Critical-load studies of a shield support

    SciTech Connect

    Barczak, T.M.; Schwemmer, D.E.

    1987-01-01

    One of the primary goals of Bureau of Mines research is to reduce the cost of coal mining by improving the efficiency of longwall supports. One method of achieving this goal is the optimization of stress distribution within the support structure, resulting in a lower over-all weight, more fully stressed shield. However, before stress optimization can be initiated, load conditions must be defined that cause maximum stress in the various support components. A finite-element model of a longwall shield was used to identify these critical load conditions. These load conditions were then evaluated in the Bureau's mine roof simulator by instrumentation of a longwall shield and measurement of strains in each of the shield components. The critical (canopy-base contact) load conditions were identified that can cause structural failure at less than rated shield (hydraulic yield) capacity. Comparisons were made between full-contact and partial-contact load conditions. Other parameters investigated included the stiffness of the contact material, changes in shield geometry, rate of load application, and effects of horizontal constraint. Conclusions are drawn regarding the structural integrity of the major shield components and potential for stress optimization.

  6. N2O emissions: modeling the effect of process configuration and diurnal loading patterns.

    PubMed

    Houweling, Dwight; Wunderlin, Pascal; Dold, Peter; Bye, Chris; Joss, Adriano; Siegrist, Hansruedi

    2011-12-01

    The objective of this research was to develop a mechanistic model for quantifying N2O emissions from activated sludge plants and demonstrate how this may be used to evaluate the effects of process configuration and diurnal loading patterns. The model describes the mechanistic link between the factors recognized to correlate positively with N2O emissions. The primary factors are the presence of ammonia and nitrite accumulation. Low dissolved oxygen concentrations also may be implicated through differential impacts on ammonia-oxidizing bacteria (AOB) versus nitrite-oxidizing bacteria (NOB) activity. Factors promoting N2O emissions at treatment plants are discussed below. The model was applied to data from laboratory and pilot-scale systems. From a practical standpoint, plant configuration (e.g., plug-flow versus complete-mix), influent loading patterns (and peak load), and certain operating strategies (e.g., handling of return streams) are all important in determining N2O emissions. PMID:22368954

  7. Estimating Critical Nitrogen Loads for a California Grassland

    NASA Astrophysics Data System (ADS)

    Weiss, S. B.

    2007-12-01

    Rigorously established critical nitrogen loads to protect biodiversity can be effective policy tools for addressing the insidious impacts of atmospheric N-deposition on ecosystems. This presentation describes methods for determining critical N-loads to a California grassland ecosystem by careful examination of the continuum from emissions, transport, atmospheric chemistry, deposition, ecosystem response, and impacts on biodiversity. Nutrient-poor soils derived from serpentinite bedrock support diverse native grasslands with dazzling wildflower displays and numerous threatened and endangered species, including the Bay checkerspot butterfly. Under moderate atmospheric N-deposition, these sites are rapidly invaded by introduced nitrophilous annual grasses in the absence of appropriate grazing or other management. Critical loads to this ecosystem have been approached by measurements of atmospheric concentrations of reactive N gases using Ogawa passive samplers and seasonally averaged deposition velocities. A regional-scale pollution gradient was complemented by a very local-scale pollution gradient extending a few hundred meters downwind of a heavily traveled road in a relatively unpolluted area. The local gradient suggests a critical load of 5 kg-N ha-1 a-1 or less. The passive monitor calculations largely agree with deposition calculated with the CMAQ model at 4 km scale. Emissions of NH3 from catalytic converters are the dominant N-source at the roadway site, and are a function of traffic volume and speed. Plant tissue N-content and 15N gradients support the existence of N-deposition gradients. The complexities of more detailed calculations and measurements specific to this ecosystem include seasonal changes in LAI, temporal coincidence of traffic emissions and stomatal conductance, surface moisture, changes in oxidized versus reduced N sources, and annual weather variation. The concept of a "critical cumulative load" may be appropriate over decadal time scales in

  8. Dissimilar phloem loading in leaves with symplasmic or apoplasmic minor-vein configurations.

    PubMed

    van Bel, A J; Gamalei, Y V; Ammerlaan, A; Bik, L P

    1992-03-01

    Plant species were selected on the basis of abundant or no symplasmic continuity between sieveelement-companion-cell (SE-CC) complexes and adjacent cells in the minor veins. Symplasmic continuity and discontinuity are denoted, respectively, as symplasmic and apoplasmic minor-vein configurations. Discs of predarkened leaves from which the lower epidermis had been removed, were exposed to (14)CO2. After 2 h of subsequent incubation, phloem loading in control discs and discs treated with p-chloromercuribenzenesulfonic acid (PCMBS) was recorded by autoradiography. Phloem loading was strongly suppressed by PCMBS in minor veins with symplasmically isolated SE-CC complexes (Centaurea, Impatiens, Ligularia, Pelargonium, Pisum, Symphytum). No significant inhibition of phloem loading by PCMBS was observed in minor veins containing sieve elements with abundant symplasmic connections (Epilobium, Fuchsia, Hydrangea, Oenothera, Origanum, Stachys). Phloem loading in minor veins with both types of SE-CC complex (Acanthus) had apoplasmic features. The results provide strong evidence for coincidence between the mode of phloem loading and the minor-vein configuration. The widespread occurrence of a symplasmic mode of phloem loading is postulated. PMID:24186781

  9. Determination of the critical loads of shells by nondestructive methods

    NASA Technical Reports Server (NTRS)

    Horton, W. H.; Nassar, E. M.; Singhal, M. K.

    1977-01-01

    Two methods for determining the location of and load level to produce instability of compressed cylindrical shells are presented. The first relates the variation in the wall normal stiffness as a function of applied compressive force to the critical load. It uses the distribution of stiffness over the surface of the shell as a guide to buckle location. The second method associates the local dynamic mass with instability behavior. The test data presented show that either method will give excellent prediction capability from low-load-level data for shells of orthodox form. Neither method appears to apply to spirally stiffened shells. This is thought to be due to the fact that there is a substantial difference between the buckle pattern under axial compression and the imperfection shape induced by the normal displacement which is used to ascertain the wall stiffness and the dynamic mass.

  10. Critical-load studies of a shield support

    SciTech Connect

    Barczak, T.M.; Schwemmer, D.E.

    1987-01-01

    One of the primary goals of Bureau of Mines research is to reduce the cost of coal mining by improving the efficiency of longwall supports. One method of achieving the goal is the optimization of stress distribution within the support structure, resulting in a lower overall weight, more fully stressed shield. However, before stress optimization can be initiated, load conditions must be defined that cause maximum stress in the various support components. A finite element model of a longwall shield was used to identify these critical load conditions. These load conditions were then evaluated in the Bureau's mine roof simulator by instrumentation of a longwall shield and measurement of strains in each of the shield components. Conclusions were drawn regarding the structural integrity of the major shield components and potential for stress optimization.

  11. Aerothermal loads analysis for high speed flow over a quilted surface configuration

    NASA Astrophysics Data System (ADS)

    Olsen, G. C.; Smith, R. E.

    1984-08-01

    Attention is given to hypersonic laminar flow over a quilted surface configuration that simulates an array of Space Shuttle Thermal Protection System panels bowed in a spherical shape as a result of thermal gradient through the panel thickness. Pressure and heating loads to the surface are determined. The flow field over the configuration was mathematically modeled by means of time-dependent, three-dimensional conservation of mass, momentum, and energy equations. A boundary mapping technique was then used to obtain a rectangular, parallel piped computational domain, and an explicit MacCormack (1972) explicit time-split predictor corrector finite difference algorithm was used to obtain steady state solutions. Total integrated heating loads vary linearly with bowed height when this value does not exceed the local boundary layer thickness.

  12. Parametric study of critical constraints for a canard configured medium range transport using conceptual design optimization

    NASA Technical Reports Server (NTRS)

    Arbuckle, P. D.; Sliwa, S. M.

    1983-01-01

    Constrained parameter optimization was used to perform optimal conceptual design of both canard and conventional configurations of a medium range transport. A number of design constants and design constraints were systematically varied to compare the sensitivities of canard and conventional configurations to a variety of technology assumptions. Main landing gear location and horizontal stabilizer high-lift performance were identified as critical design parameters for a statically stable, subsonic canard transport.

  13. Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for mediterranean evergreen woodlands

    NASA Astrophysics Data System (ADS)

    Pinho, P.; Theobald, M. R.; Dias, T.; Tang, Y. S.; Cruz, C.; Martins-Loução, M. A.; Máguas, C.; Sutton, M.; Branquinho, C.

    2011-11-01

    Nitrogen (N) has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds have been established, such as critical loads (deposition fluxes) and levels (concentrations). For Mediterranean ecosystems, few studies have been carried out to assess these parameters. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for Mediterranean evergreen woodlands. For that we have considered changes in epiphytic lichen communities, which have been shown to be one of the most sensitive to excessive N. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done under Mediterranean climate, in evergreen cork-oak woodlands, by sampling lichen functional diversity and annual atmospheric ammonia concentrations and modelling N deposition downwind from a reduced N source (a cattle barn). By modelling the highly significant relationship between lichen functional groups and N deposition, the critical load was estimated to be below 26 kg (N) ha-1 yr-1, which is within the upper range established for other semi-natural ecosystems. By modelling the highly significant relationship of lichen functional groups with annual atmospheric ammonia concentration, the critical level was estimated to be below 1.9 μg m-3, in agreement with recent studies for other ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should be taken into account in policies that aim at protecting Mediterranean woodlands from the initial effects of excessive N.

  14. Scale-4 Analysis of Pressurized Water Reactor Critical Configurations: Volume 3-Surry Unit 1 Cycle 2

    SciTech Connect

    Bowman, S.M.

    1995-01-01

    The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor criticality safety analyses be validated against experimental measurements. If credit for the negative reactivity of the depleted (or spent) fuel isotopics is desired, it is necessary to benchmark computational methods against spent fuel critical configurations. This report summarizes a portion of the ongoing effort to benchmark away-from-reactor criticality analysis methods using selected critical configurations from commercial pressurized-water reactors. The analysis methodology selected for all the calculations in this report is based on the codes and data provided in the SCALE-4 code system. The isotopic densities for the spent fuel assemblies in the critical configurations were calculated using the SAS2H analytical sequence of the SCALE-4 system. The sources of data and the procedures for deriving SAS2H input parameters are described in detail. The SNIKR code module was used to extract the necessary isotopic densities from the SAS2H results and to provide the data in the format required by the SCALE criticality analysis modules. The CSASN analytical sequence in SCALE-4 was used to perform resonance processing of the cross sections. The KENO V.a module of SCALE-4 was used to calculate the effective multiplication factor (k{sub eff}) of each case. The SCALE-4 27-group burnup library containing ENDF/B-IV (actinides) and ENDF/B-V (fission products) data was used for all the calculations. This volume of the report documents the SCALE system analysis of two reactor critical configurations for Surry Unit 1 Cycle 2. This unit and cycle were chosen for a previous analysis using a different methodology because detailed isotopics from multidimensional reactor calculations were available from the Virginia Power Company. These data permitted a direct comparison of criticality calculations using the utility-calculated isotopics with those using the isotopics generated by the SCALE-4

  15. Transition of oxide film configuration and the critical stress inferred by scanning probe microscopy at nanoscale

    NASA Astrophysics Data System (ADS)

    Fang, Xufei; Li, Yan; Zhang, Changxing; Dong, Xuelin; Feng, Xue

    2016-09-01

    Scanning probe microscopy (SPM) equipped in high temperature nanoindentation instrument is adopted to in situ characterize the oxide film growth on Ni-base single crystal at nanoscale. SPM images reveal a transition of oxide film configuration that the originally flat surface roughens during oxidation. Based on the stress-diffusion coupling effect during oxidation, the stress evolution in the oxide film and the evolution of surface configuration are analyzed. A new method to infer the critical stress in the oxide film at the transition point is proposed by measuring the undulated surface wavelength based on the surface morphology obtained by SPM.

  16. Air Pollution Critical Loads in the U.S.: Past, Present and Future

    NASA Astrophysics Data System (ADS)

    Blett, T. F.

    2012-12-01

    "Critical loads" describe the amount of air pollution initiating harmful changes in sensitive ecosystems. Critical loads generally have both a "science" component, describing the amount of deposition needed to alter chemical indicators (such as surface water acid neutralizing capacity) or biological endpoints (such as lichen biodiversity) and a "policy" component where critical loads are evaluated and utilized to help make land management or regulatory decisions. Critical loads science and policy have both made substantial headway in the U.S. over the past decade. For example, a recent review of critical loads of nitrogen cited over 300 published papers relevant to critical loads development in the U.S. The National Atmospheric Deposition Program's Critical Loads Science Subcommittee (CLAD) has recently synthesized most available U.S. critical loads data into a national-scale database and used it to develop maps for modeled surface water acidification, modeled soil acidification, and empirically derived excess nitrogen effects. Air quality regulators and land managers are increasingly using critical loads, in conjunction with policy objectives, to establish goals (target loads) for deposition reductions needed to improve sensitive resource conditions in impacted areas. These goals help focus air pollution emissions reduction efforts where they will be most effective. We will discuss critical loads history in the U.S., provide an overview of some of the most recent national-scale critical loads products, and outline future needs.

  17. Effect of load carriage on gait due to firefighting air bottle configuration.

    PubMed

    Park, Kiwon; Hur, Pilwon; Rosengren, Karl S; Horn, Gavin P; Hsiao-Wecksler, Elizabeth T

    2010-07-01

    The air bottle configuration (mass and size) used with a firefighter's self-contained breathing apparatus may affect functional gait performance and slip/trip/fall risk, contributing to one of the most common and costly fire ground injuries to this population. To examine the potential effect of bottle mass and size on firefighter gait performance, four 30-min air bottle configurations were tested. To quantify biomechanical gait performance, kinetic and kinematic gait data were collected on 24 male firefighters while walking at normal and fast speeds during three conditions (no obstacle, 10 cm or 30 cm stationary obstacle). Bottle mass, obstacle height and walking speed - but not bottle size - were found to significantly impact gait parameters. Ten subjects (42%) contacted the taller obstacle while wearing heavier bottles, suggesting greater risk for tripping. Heavier bottles also resulted in larger forces by the trailing leg in both the anterior-posterior and vertical directions, suggesting greater risk for slipping. These results suggest that increased bottle weight may result in a decrease in gait performance and an increase in fall risk. STATEMENT OF RELEVANCE: Occupations, such as firefighting, often require use of a self-contained breathing apparatus that includes a pressurised air bottle. No systematic assessment has investigated how modest changes in load carriage due to bottle configuration (mass and size) might affect gait behaviour, especially when crossing obstacles. Bottle mass, but not size, was found to decrease gait performance and increase fall risk. PMID:20582769

  18. Nitrogen removal from high organic loading wastewater in modified Ludzack-Ettinger configuration MBBR system.

    PubMed

    Torkaman, Mojtaba; Borghei, Seyed Mehdi; Tahmasebian, Sepehr; Andalibi, Mohammad Reza

    2015-01-01

    A moving bed biofilm reactor with pre-denitrification configuration was fed with a synthetic wastewater containing high chemical oxygen demand (COD) and ammonia. By changing different variables including ammonium and COD loading, nitrification rate in the aerobic reactor and denitrification rate in the anoxic reactor were monitored. Changing the influent loading was achieved via adjusting the inlet COD (956-2,096 mg/L), inlet ammonium (183-438 mg/L), and hydraulic retention time of the aerobic reactor (8, 12, and 18 hours). The overall organic loading rate was in the range of 3.60-17.37 gCOD/m2·day, of which 18.5-91% was removed in the anoxic reactor depending on the operational conditions. Considering the complementary role of the aerobic reactor, the overall COD removal was in the range 87.3-98.8%. In addition, nitrification rate increased with influent ammonium loading, the maximum rate reaching 3.05 gNH4/m2·day. One of the most important factors affecting nitrification rate was influent C:N entering the aerobic reactor, by increasing which nitrification rate decreased asymptotically. Nitrate removal efficiency in the anoxic reactor was also controlled by the inlet nitrate level entering the anoxic reactor. Furthermore, by increasing the nitrate loading rate from 0.91 to 3.49 gNO/m3·day, denitrification rate increased from 0.496 to 2.47 gNO/m3·day. PMID:26465296

  19. SCALE-4 Analysis of LaSalle Unit 1 BWR Commercial Reactor Critical Configurations

    SciTech Connect

    Gauld, I.C.

    2000-03-01

    Five commercial reactor criticals (CRCs) for the LaSalle Unit 1 boiling-water reactor have been analyzed using KENO V.a, the Monte Carlo criticality code of the SCALE 4 code system. The irradiated fuel assembly isotopics for the criticality analyses were provided by the Waste Package Design team at the Yucca Mountain Project in the US, who performed the depletion calculations using the SAS2H sequence of SCALE 4. The reactor critical measurements involved two beginning-of-cycle and three middle-of-cycle configurations. The CRCs involved relatively low-cycle burnups, and therefore contained a relatively high gadolinium poison content in the reactor assemblies. This report summarizes the data and methods used in analyzing the critical configurations and assesses the sensitivity of the results to some of the modeling approximations used to represent the gadolinium poison distribution within the assemblies. The KENO V.a calculations, performed using the SCALE 44GROUPNDF5 ENDF/B-V cross-section library, yield predicted k{sub eff} values within about 1% {Delta}k/k relative to reactor measurements for the five CRCs using general 8-pin and 9-pin heterogeneous gadolinium poison pin assembly models.

  20. SCALE-4 Analysis of LaSalle Unit 1 BWR Commercial Reactor Critical Configuration

    SciTech Connect

    Gauld, I.C.

    2000-03-16

    Five commercial reactor criticals (CRCs) for the LaSalle Unit 1 boiling-water reactor have been analyzed using KENO V.a, the Monte Carlo criticality code of the SCALE 4 code system. The irradiated fuel assembly isotopics for the criticality analyses were provided by the Waste Package Design team at the Yucca Mountain Project in the United States, who performed the depletion calculations using the SAS2H sequence of SCALE 4. The reactor critical measurements involved two beginning-of-cycle and three middle-of-cycle configurations. The CRCs involved relatively low-cycle burnups, and therefore contained a relatively high gadolinium poison content in the reactor assemblies. This report summarizes the data and methods used in analyzing the critical configurations and assesses the sensitivity of the results to some of the modeling approximations used to represent the gadolinium poison distribution within the assemblies. The KENO V.a calculations, performed using the SCALE 44GROUPNDF5 ENDF/B-V cross-section library, yield predicted k{sub eff} values within about 1% {Delta}k/k relative to reactor measurements for the five CRCs using general 8-pin and 9-pin heterogeneous gadolinium poison pin assembly models.

  1. Critical configurations (determinantal loci) for range and range difference satellite networks

    NASA Technical Reports Server (NTRS)

    Tsimis, E.

    1973-01-01

    The observational modes of Geometric Satellite Geodesy are discussed. The geometrical analysis of the problem yielded a regression model for the adjustment of the observations along with a suitable and convenient metric for the least-squares criterion. The determinantal loci (critical configurations) for range networks are analyzed. An attempt is made to apply elements of the theory of variants for this purpose. The use of continuously measured range differences for loci determination is proposed.

  2. Final report for the field-reversed configuration power plant critical-issue scoping study

    SciTech Connect

    Santarius, John F.; Mogahed, Elsayed A.; Emmert, Gilbert A.; Khater, Hesham Y.; Nguyen, Canh N.; Ryzhkov, Sergei V.; Stubna, Michael D.; Steinhauer, Loren C.; Miley, George H.

    2001-03-01

    This report describes research in which a team from the Universities of Wisconsin, Washington, and Illinois performed a scoping study of critical issues for field-reversed configuration (FRC) power plants. The key tasks for this research were (1) systems analysis of deuterium-tritium (D-T) FRC fusion power plants, and (2) conceptual design of the blanket and shield module for an FRC fusion core.

  3. Scale-4 Analysis of Pressurized Water Reactor Critical Configurations: Volume 4-Three Mile Island Unit 1 Cycle 5

    SciTech Connect

    DeHart, M.D.

    1995-01-01

    The requirements of ANSI/ANS-8.1 specify that calculational methods for away-from-reactor criticality safety analyses be validated against experimental measurements. If credit is to be taken for the reduced reactivity of burned or spent fuel relative to its original ''fresh'' composition, it is necessary to benchmark computational methods used in determining such reactivity worth against spent fuel reactivity measurements. This report summarizes a portion of the ongoing effort to benchmark away-from-reactor criticality analysis methods using relevant and well-documented critical configurations from commercial pressurized water reactors. The analysis methodology utilized for all calculations in this report is based on the modules and data associated with the SCALE-4 code system. Isotopic densities for spent fuel assemblies in the core were calculated using the SCALE-4 SAS2H analytical sequence. The sources of data and the procedures for deriving SAS2H input parameters are described in detail. The SNIKR code family was used to extract the necessary isotopic densities from SAS2H results and to provide the data in the format required for SCALE criticality analysis modules. The CSASN analytical sequence in SCALE-4 was used to perform resonance processing of cross sections. The KENO V.a module of SCALE-4 was used to calculate the effective multiplication factor (k{sub eff}) for the critical configuration. The SCALE-4 27-group burnup library containing ENDF/B-IV (actinides) and ENDF/B-V (fission products) data was used for all calculations. This volume of the report documents a reactor critical calculation for GPU Nuclear Corporation's Three Mile Island Unit 1 (TMI-1) during hot, zero-power startup testing for the beginning of cycle 5. This unit and cycle were selected because of their relevance in spent fuel benchmark applications: (1) cycle 5 startup occurred after an especially long downtime of 6.6 years; and (2) the core consisted primarily (75%) of burned fuel, with

  4. Scale-4 Analysis of Pressurized Water Reactor Critical Configurations: Volume 1-Summary

    SciTech Connect

    DeHart, M.D.

    1995-01-01

    The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor criticality safety analyses be validated against experimental measurements. If credit is to be taken for the reduced reactivity of burned or spent fuel relative to its original ''fresh'' composition, it is necessary to benchmark computational methods used in determining such reactivity worth against spent fuel reactivity measurements. This report summarizes a portion of the ongoing effort to benchmark away-from-reactor criticality analysis methods using critical configurations from commercial pressurized- water reactors (PWR). The analysis methodology utilized for all calculations in this report is based on the modules and data associated with the SCALE-4 code system. Isotopic densities for spent fuel assemblies in the core were calculated using the SAS2H analytical sequence in SCALE-4. The sources of data and the procedures for deriving SAS2H input parameters are described in detail. The SNIKR code sequence was used to extract the necessary isotopic densities from SAS2H results and to provide the data in the format required for SCALE-4 criticality analysis modules. The CSASN analytical sequence in SCALE-4 was used to perform resonance processing of cross sections. The KENO V.a module of SCALE-4 was used to calculate the effective multiplication factor (k{sub eff}) for the critical configuration. The SCALE-4 27-group burnup library containing ENDF/B-IV (actinides) and ENDF/B-V (fission products) data was used for analysis of each critical configuration. Each of the five volumes comprising this report provides an overview of the methodology applied. Subsequent volumes also describe in detail the approach taken in performing criticality calculations for these PWR configurations: Volume 2 describes criticality calculations for the Tennessee Valley Authority's Sequoyah Unit 2 reactor for Cycle 3; Volume 3 documents the analysis of Virginia Power's Surry Unit 1 reactor for the

  5. SSME/side loads analysis for flight configuration, revision A. [structural analysis of space shuttle main engine under side load excitation

    NASA Technical Reports Server (NTRS)

    Holland, W.

    1974-01-01

    This document describes the dynamic loads analysis accomplished for the Space Shuttle Main Engine (SSME) considering the side load excitation associated with transient flow separation on the engine bell during ground ignition. The results contained herein pertain only to the flight configuration. A Monte Carlo procedure was employed to select the input variables describing the side load excitation and the loads were statistically combined. This revision includes an active thrust vector control system representation and updated orbiter thrust structure stiffness characteristics. No future revisions are planned but may be necessary as system definition and input parameters change.

  6. Critical Configuration and Physics Measurements for Assemblies of U(93.15)O2 Fuel Rods

    SciTech Connect

    Margaret A. Marshall

    2013-03-01

    A series of critical experiments were completed in 1962-1965 at Oak Ridge National Laboratory’s (ORNL’s) Critical Experiments Facility (CEF) in support of the Medium-Power Reactor Experiments (MPRE) program. In the late 1950s, efforts were made to study “power plants for the production of electrical power in space vehicles.”(a) The MPRE program was a part of those efforts and studied the feasibility of a stainless-steel system, boiling potassium 1 MW(t), or about 140 kW(e), reactor. The program was carried out in [fiscal years] 1964, 1965, and 1966. A summary of the program’s effort was compiled in 1967. The delayed critical experiments were a mockup of a small, potassium-cooled space power reactor for validation of reactor calculations and reactor physics methods. Initial experiments, performed in November and December of 1962, consisted of a core of unmoderated stainless-steel tubes, each containing 26 UO2 fuel pellets, surrounded by a graphite reflector. Measurements were made to determine critical reflector arrangements, fission-rate distributions, and cadmium ratio distributions. Subsequent experiments used beryllium reflectors and also measured the reactivity for various materials placed in the core. “The [assemblies were built] on [a] vertical assembly machine so that the movable part was the core and bottom reflector.”(Reference 1) The experiment studied in this evaluation was the first of the series and had the fuel tubes packed tightly into a 22.87 cm outside diameter (OD) core tank. Two critical configurations were found by varying the amount of graphite reflector (References 1 and 2). Once the critical configurations had been achieved, various measurements of reactivity, relative axial and radial activation rates of 235U, , and cadmium ratios were performed. The cadmium ratio, reactivity, and activation rate measurements performed on the critical configurations are described in Sections 1.3, 1.4 and 1.7, respectively. Information for this

  7. Critical Configuration and Physics Measurements for Assemblies of U(93.15)O2 Fuel Rods

    SciTech Connect

    Margaret A. Marshall

    2012-09-01

    A series of critical experiments were completed in 1962-1965 at Oak Ridge National Laboratory’s (ORNL’s) Critical Experiments Facility (CEF) in support of the Medium-Power Reactor Experiments (MPRE) program. In the late 1950s, efforts were made to study “power plants for the production of electrical power in space vehicles.”(a) The MPRE program was a part of those efforts and studied the feasibility of a stainless-steel system, boiling potassium 1 MW(t), or about 140 kW(e), reactor. The program was carried out in [fiscal years] 1964, 1965, and 1966. A summary of the program’s effort was compiled in 1967. The delayed critical experiments were a mockup of a small, potassium-cooled space power reactor for validation of reactor calculations and reactor physics methods. Initial experiments, performed in November and December of 1962, consisted of a core of unmoderated stainless-steel tubes, each containing 26 UO2 fuel pellets, surrounded by a graphite reflector. Measurements were made to determine critical reflector arrangements, fission-rate distributions, and cadmium ratio distributions. Subsequent experiments used beryllium reflectors and also measured the reactivity for various materials placed in the core. “The [assemblies were built] on [a] vertical assembly machine so that the movable part was the core and bottom reflector.”(Reference 1) The experiment studied in this evaluation was the first of the series and had the fuel tubes packed tightly into a 22.87 cm outside diameter (OD) core tank. Two critical configurations were found by varying the amount of graphite reflector (References 1 and 2). Once the critical configurations had been achieved, various measurements of reactivity, relative axial and radial activation rates of 235U, , and cadmium ratios were performed. The cadmium ratio, reactivity, and activation rate measurements performed on the critical configurations are described in Sections 1.3, 1.4 and 1.7, respectively. Information for this

  8. Creep of a Silicon Nitride Under Various Specimen/Loading Configurations

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Powers, Lynn M.; Holland, Frederic A.; Gyekenyesi, John P.; Holland, F. A. (Technical Monitor)

    2000-01-01

    Extensive creep testing of a hot-pressed silicon nitride (NC132) was performed at 1300 C in air using five different specimen/loading configurations, including pure tension, pure compression, four-point uniaxial flexure, ball-on-ring biaxial flexure, and ring-on-ring biaxial flexure. Nominal creep strain and its rate for a given nominal applied stress were greatest in tension, least in compression, and intermediate in uniaxial and biaxial flexure. Except for the case of compressive loading, nominal creep strain generally decreased with time, resulting in less-defined steady-state condition. Of the four different creep formulations - power-law, hyperbolic sine, step, redistribution models - the conventional power-law model still provides the most convenient and reasonable means to estimate simple, quantitative creep parameters of the material. Predictions of creep deformation for the case of multiaxial stress state (biaxial flexure) were made based on pure tension and compression creep data by using the design code CARES/Creep.

  9. Loading Configurations and Ground Reaction Forces During Treadmill Running in Weightlessness

    NASA Technical Reports Server (NTRS)

    DeWitt, John; Schaffner, Grant; Blazine, Kristi; Bentley, Jason; Laughlin, Mitzi; Loehr, James; Hagan, Donald

    2003-01-01

    Studies have shown losses in bone mineral density of 1-2% per month in critical weight bearing areas such as the proximal femur during long-term space flight (Grigoriev, 1998). The astronauts currently onboard the International Space Station (ISS) use a treadmill as an exercise countermeasure to bone loss that occurs as a result of prolonged exposure to weightlessness. A crewmember exercising on the treadmill is attached by a harness and loading device. Ground reaction forces are obtained through the loading device that pulls the crewn1ember towards the treadmill surface during locomotion. McCrory et al. (2002) found that the magnitude of the peak ground reaction force (pGRF) during horizontal suspension running, or simulated weightlessness, was directly related to the load applied to the subject. It is thought that strain magnitude and strain rate affects osteogenesis, and is a function of the magnitude and rate of change of the ground reaction force. While it is not known if a minimum stimulus exists for osteogenesis, it has been hypothesized that in order to replicate the bone formation occurring in normal gravity (1 G), the exercise in weightlessness should mimic the forces that occur on earth. Specifically, the pGRF obtained in weightlessness should be comparable to that achieved in 1 G.

  10. Scale-4 analysis of pressurized water reactor critical configurations: Volume 5, North Anna Unit 1 Cycle 5

    SciTech Connect

    Bowman, S.M.; Suto, T. |

    1996-10-01

    ANSI/ANS 8.1 requires that calculational methods for away-from- reactor (AFR) criticality safety analyses be validated against experiment. This report summarizes part of the ongoing effort to benchmark AFR criticality analysis methods using selected critical configurations from commercial PWRs. Codes and data in the SCALE-4 code system were used. This volume documents the SCALE system analysis of one reactor critical configuration for North Anna Unit 1 Cycle 5. The KENO V.a criticality calculations for the North Anna 1 Cycle 5 beginning-of-cycle model yielded a value for k{sub eff} of 1. 0040{+-}0.0005.

  11. Moment ratios and dynamic critical behavior of a reactive system with several absorbing configurations.

    PubMed

    de Andrade, M F; Figueiredo, W

    2011-03-01

    We determine the critical behavior of a reactive model with many absorbing configurations. Monomers A and B land on the sites of a linear lattice and can react depending on the state of their nearest-neighbor sites. The probability of a reaction depends on temperature of the catalyst as well as on the energy coupling between pairs of nearest-neighbor monomers. We employ Monte Carlo simulations to calculate the moments of the order parameter of the model as a function of temperature. Some ratios between pairs of moments are independent of temperature and are in the same universality class of the contact process. We also find the dynamical critical exponents of the model and we show that they are in the directed percolation universality class whatever the values of temperature. PMID:21517455

  12. The geometric configuration and morphometry of the rabbit oesophagus during luminal pressure loading.

    PubMed

    Liao, Donghua; Cassin, Jeff; Zhao, Jingbo; Gregersen, Hans

    2006-08-01

    The aim of the present study was to determine the geometric configuration and morphometric dimensions in the rabbit oesophagus during luminal pressure loading. The geometric configuration is of fundamental importance because it is related to stress and strain and determines the resistance to flow. The oesophagus was excised from rabbits, transferred to an organ bath and stretched to the in vivo length. Cannulas were inserted into both ends and each oesophagus was subjected to a luminal pressure up to 0, 1, 2, 5 and 10 cm H(2)O. After equilibrium was reached, the oesophagus was snap-frozen in liquid nitrogen. Sections were cut from five locations in the oesophagus and videotaped in the frozen state. Geometric and morphometric data including perimeter, circularities, area, thickness, buckles and strains in different layers were obtained from the video images. These variables did not show axial variation in the oesophagus. All variables changed as a function of the pressure. The whole wall thickness decreased as an inverse function of the pressure. The thickness decrease was mainly due to thinning of the submucosa and muscle. The number of buckles decreased from 4.05 +/- 0.34 at 0 cm H(2)O pressure to 0.07 +/- 0.07 at 10 cm H(2)O. Circumferential Green strain-pressure curves for the various layers all showed an exponential pattern. The curve obtained at the submucosa-muscle layer interface was located to the right of the other curves, indicating that the muscle layer was softest. The data obtained in this study will be useful for further modelling of the mechanics of the oesophagus. PMID:16772669

  13. SECOND WASTE PACKAGE PROBABILISTIC CRITICALITY ANALYSIS: GENERATION AND EVALUATION OF INTERNAL CRITICIALITY CONFIGURATIONS

    SciTech Connect

    P. Gottlieb, J.R. Massari, J.K. McCoy

    1996-03-27

    This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department to provide an evaluation of the criticality potential within a waste package having sonic or all of its contents degraded by corrosion and removal of neutron absorbers. This analysis is also intended to provide an estimate of the consequences of any internal criticality, particularly in terms of any increase in radionuclide inventory. These consequence estimates will be used as part of the WPD input to the Total System Performance Assessment. The ultimate objective of this analysis is to augment the information gained from the Initial Waste Package Probabilistic Criticality Analyses (Ref. 5.8 and 5.9, hereafter referred to as IPA) to a degree which will support preliminary waste package design recommendations intended to reduce the risk of waste package criticality and the risk to total repository system performance posed by the consequences of any criticality. The IPA evaluated the criticality potential under the assumption that the waste package basket retained its structural integrity, so that the assemblies retained their initial separation, even when the neutron absorbers had been leached from the basket. This analysis is based on the more realistic condition that removal of the neutron absorbers is a consequence of the corrosion of the steel in which they are contained, which has the additional consequence of reducing the structural support between assemblies. The result is a set of more reactive configurations having a smaller spacing between assemblies, or no inter-assembly spacing at all. Another difference from the IPA is the minimal attention to probabilistic evaluation given in this study. Although the IPA covered a time horizon to 100,000 years, the lack of consideration of basket degradation modes made it primarily applicable to the first 10,000 years. In contrast, this study, by focusing on the degraded modes of the basket, is primarily

  14. Estimates of critical acid loads and exceedances for forest soils across the conterminous United States.

    PubMed

    McNulty, Steven G; Cohen, Erika C; Moore Myers, Jennifer A; Sullivan, Timothy J; Li, Harbin

    2007-10-01

    Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A pollutant load in excess of a critical acid load is termed exceedance. This study combined a simple mass balance equation with national-scale databases to estimate critical acid load and exceedance for forest soils at a 1-km(2) spatial resolution across the conterminous US. This study estimated that about 15% of US forest soils are in exceedance of their critical acid load by more than 250eqha(-1)yr(-1), including much of New England and West Virginia. Very few areas of exceedance were predicted in the western US. PMID:17629382

  15. Empirical Critical Loads of Atmospheric Nitrogen Deposition for Nutrient Enrichment and Acidification of Sensitive US Lakes

    EPA Science Inventory

    A critical load is a “quantitative estimate of the exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge”. Critical loads can be either modeled, or calculated empi...

  16. Field-Reversed Configuration Power Plant Critical-Issue Scoping Study

    SciTech Connect

    Santarius, J. F.; Mogahed, E. A.; Emmert, G. A.; Khater, H. Y.; Nguyen, C. N.; Ryzhkov, S. V.; Stubna, M. D.

    2000-03-31

    A team from the Universities of Wisconsin, Washington, and Illinois performed an engineering scoping study of critical issues for field-reversed configuration (FRC) power plants. The key tasks for this research were (1) systems analysis for deuterium-tritium (D-T) FRC fusion power plants, and (2) conceptual design of the blanket and shield module for an FRC fusion core. For the engineering conceptual design of the fusion core, the project team focused on intermediate-term technology. For example, one decision was to use steele structure. The FRC systems analysis led to a fusion power plant with attractive features including modest size, cylindrical symmetry, good thermal efficiency (52%), relatively easy maintenance, and a high ratio of electric power to fusion core mass, indicating that it would have favorable economics.

  17. [Mapping Critical Loads of Heavy Metals for Soil Based on Different Environmental Effects].

    PubMed

    Shi, Ya-xing; Wu, Shao-hua; Zhou, Sheng-lu; Wang, Chun-hui; Chen, Hao

    2015-12-01

    China's rapid development of industrialization and urbanization causes the growing problem of heavy metal pollution of soil, threatening environment and human health. Therefore, prevention and management of heavy metal pollution become particularly important. Critical loads of heavy metals are an important management tool that can be utilized to prevent the occurrence of heavy metal pollution. Our study was based on three cases: status balance, water environmental effects and health risks. We used the steady-state mass balance equation to calculate the critical loads of Cd, Cu, Pb, Zn at different effect levels and analyze the values and spatial variation of critical loads. In addition, we used the annual input fluxes of heavy metals of the agro-ecosystem in the Yangtze River delta and China to estimate the proportion of area with exceedance of critical loads. The results demonstrated that the critical load value of Cd was the minimum, and the values of Cu and Zn were lager. There were spatial differences among the critical loads of four elements in the study area, lower critical loads areas mainly occurred in woodland and high value areas distributed in the east and southwest of the study area, while median values and the medium high areas mainly occurred in farmland. Comparing the input fluxes of heavy metals, we found that Pb and Zn in more than 90% of the area exceeded the critical loads under different environmental effects in the study area. The critical load exceedance of Cd mainly occurred under the status balance and the water environmental effect, while Cu under the status balance and water environmental effect with a higher proportion of exceeded areas. Critical loads of heavy metals at different effect levels in this study could serve as a reference from effective control of the emissions of heavy metals and to prevent the occurrence of heavy metal pollution. PMID:27011999

  18. Climate Change Impacts on Forest Soils Critical Acid Loads and Exceedances at a National Scale

    NASA Astrophysics Data System (ADS)

    McNulty, S. G.; Cohen, E.; Moore Myers, J.; Sun, G.; Caldwell, P.

    2011-12-01

    The Federal agencies of the United States (US) are currently developing guidelines for forest soil critical acid loads across the US. A critical acid load is defined as the amount of acid deposition (usually expressed on a annual basis) that an ecosystem can absorb. Traditionally, an ecosystem is considered to be at risk for health impairment when the critical acid load exceeds a level known to impair forest health. The excess over the critical acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical acid load applies to a single, long-term pollutant exposure. These guidelines are often used to establish regulations designed to maintain acidic deposition (e.g., nitrogen and sulfur) inputs below the level shown to exceed an ecosystem's critical acid load. The traditional definition for a critical acid load generally assume that the ecosystem is in a steady state condition (i.e. no major changes in the factors that regulate the ecosystems ability to absorb acids. Unfortunately, climate change is altering weather patterns and, thus, impacting the factors that regulate critical acid load limits. This paper explores which factors associated with establishing forest soil critical acid load limits will most likely be influenced by climate change, and how these changes might impact forest soil critical acid load limits across the US. Base cation weathering could increase with global warming, along with nitrogen uptake as a function of increased forest growth across New England. A moderate 20% increase in base cation weathering and nitrogen uptake would result in at least a 25% decrease in the amount of forest soil area that exceeded the critical acid load limit and at least a 50% decrease in the amount of high exceedance area across the US. While these results are encouraging, they do not account for other negative potential forest health risks associated with climate change such as elevated

  19. Development and Implementation of Critical Loads for Atmospheric Deposition: Federal Land Management Implications

    NASA Astrophysics Data System (ADS)

    Porter, E. M.

    2004-12-01

    Critical loads for atmospheric deposition have been widely developed and used in Europe, Canada, and other countries. Critical loads are used to influence air pollution emissions reductions, thereby protecting and restoring aquatic and terrestrial ecosystems. In the United States, federal land management agencies are adopting the critical load concept as a potentially valuable resource management tool. Certain parks and wilderness areas are currently being affected by anthropogenic nitrogen and sulfur deposition. Effects of excess deposition include acidification, nitrogen enrichment, toxicity, and changes in biotic communities. Streams in both Shenandoah and Great Smoky Mountains National Parks are experiencing chronic and episodic acidification and brook trout fisheries in Shenandoah have been affected. High elevation ecosystems in Rocky Mountain National Park are undergoing subtle changes in aquatic and terrestrial ecosystems attributable to atmospheric deposition. Natural resources in many other federal areas have been affected or are at risk from deposition. Federal land managers are refining strategies for critical loads that include working with scientists to identify resources sensitive to deposition, defining resource protection criteria that will meet management objectives, and estimating and implementing critical loads. Critical loads will be used in resource management decisions and federal land management planning. They will be used to evaluate management actions and assess progress towards meeting management goals. Federal land managers will also communicate critical loads information to air pollution regulatory agencies to inform emissions management strategies for clean air.

  20. Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands

    NASA Astrophysics Data System (ADS)

    Pinho, P.; Theobald, M. R.; Dias, T.; Tang, Y. S.; Cruz, C.; Martins-Loução, M. A.; Máguas, C.; Sutton, M.; Branquinho, C.

    2012-03-01

    Nitrogen (N) has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds such as critical loads (deposition fluxes) and levels (concentrations) can be established. Few studies have assessed these thresholds for semi-natural Mediterranean ecosystems. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands. We have considered changes in epiphytic lichen communities, one of the most sensitive comunity indicators of excessive N in the atmosphere. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done for a Mediterranean climate in evergreen cork-oak woodlands, based on the relation between lichen functional diversity and modelled N deposition for critical loads and measured annual atmospheric ammonia concentrations for critical levels, evaluated downwind from a reduced N source (a cattle barn). Modelling the highly significant relationship between lichen functional groups and annual atmospheric ammonia concentration showed the critical level to be below 1.9 μg m-3, in agreement with recent studies for other ecosystems. Modelling the highly significant relationship between lichen functional groups and N deposition showed that the critical load was lower than 26 kg (N) ha-1 yr-1, which is within the upper range established for other semi-natural ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should aid development of policies to protect Mediterranean woodlands from the initial effects of excessive N.

  1. Modeling and mapping of critical loads for heavy metals in Kunshan soil.

    PubMed

    Wu, Shaohua; Shi, Yaxing; Zhou, Shenglu; Wang, Chunhui; Chen, Hao

    2016-11-01

    The assessment of critical loads of metals in soil can be used as an important tool for evaluation and for risk precaution of future inputs of metal in order to avoid the occurrence of heavy metal pollution and its long-term risks for people. In this study, critical loads of Cd, Cu, and Pb in farming and non-farming areas of Kunshan were calculated based on three main effects. Two of these effects, limit value of daily metals dose and different environmental water quality criteria are new ways to calculate the critical content of heavy metals. The mean value of critical loads decreased in the order Cu>Pb>Cd when calculated using mass balance effects, child health risk effects, and adult health risk effects. Critical loads were highest in the areas near construction land, areas of low critical load were scattered throughout the city. The areal proportion of critical load exceedance is greatest for Pb based on mass balance effects, followed by Cu based on water quality effects, and Cd based on mass balance effects. Exceedances only occurred in 6% and 3% of farming areas for water quality effects for Cd and Pb when compared critical load values to the input fluxes in the Yangtze River delta. However, for these metals, values were up to 83% and 100%, respectively, based on mass balance effects. Exceedances completely covered non-farming areas for each effect for Pb. Most exceedances occurred in the north and south of the city in non-farming areas. Spatially explicit critical loads of heavy metals based on the different effects can serve as a reference for controlling the emissions of heavy metals effectively and meeting the demands of different management objectives. PMID:27343938

  2. Debonding in Composite Skin/Stringer Configurations Under Multi-Axial Loading

    NASA Technical Reports Server (NTRS)

    Cvitkovich, Michael K.; Krueger, Ronald; OBrien, T.; Minguet, Pierre J.

    2004-01-01

    The objective of this work was to investigate the damage mechanisms in composite bonded skin/stringer constructions under uniaxial and biaxial (in-plane/out-of-plane) loading conditions as typically experienced by aircraft crown fuselage panels. The specimens for all tests were identical and consisted of a tapered composite flange, representing a stringer or frame, bonded onto a composite skin. Tests were performed under monotonic loading conditions in tension, three-point bending, and combined tension/bending to evaluate the debonding mechanisms between the skin and the bonded stringer. For combined tension/bending testing, a unique servohydraulic load frame was used that was capable of applying both loads simultaneously. Microscopic investigations of the specimen edges were used to document the damage occurrence and to identify typical damage patterns. The observations showed that, for all three load cases, failure initiated in the flange near the flange tip causing the flange to almost fully debond from the skin. A two-dimensional plain-strain finite element model was developed to analyze the different test cases using a geometrically nonlinear solution. For all three loading conditions, principal stresses exceeded the transverse strength of the material in the flange area. Additionally, delaminations of various lengths were simulated in the locations where delaminations were experimentally observed. The analyses showed that unstable delamination propagation is likely to occur at the loads corresponding to matrix ply crack initiation for all three loadings.

  3. Load and dynamic assessment of B-52B-008 carrier aircraft for finned configuration 1 space shuttle solid rocket booster decelerator subsystem drop test vehicle. Volume 2: Airplane flutter and load analysis results

    NASA Technical Reports Server (NTRS)

    Quade, D. A.

    1978-01-01

    The airplane flutter and maneuver-gust load analysis results obtained during B-52B drop test vehicle configuration (with fins) evaluation are presented. These data are presented as supplementary data to that given in Volume 1 of this document. A brief mathematical description of airspeed notation and gust load factor criteria are provided as a help to the user. References are defined which provide mathematical description of the airplane flutter and load analysis techniques. Air-speed-load factor diagrams are provided for the airplane weight configurations reanalyzed for finned drop test vehicle configuration.

  4. CRITICAL ASSUMPTIONS IN THE F-TANK FARM CLOSURE OPERATIONAL DOCUMENTATION REGARDING WASTE TANK INTERNAL CONFIGURATIONS

    SciTech Connect

    Hommel, S.; Fountain, D.

    2012-03-28

    The intent of this document is to provide clarification of critical assumptions regarding the internal configurations of liquid waste tanks at operational closure, with respect to F-Tank Farm (FTF) closure documentation. For the purposes of this document, FTF closure documentation includes: (1) Performance Assessment for the F-Tank Farm at the Savannah River Site (hereafter referred to as the FTF PA) (SRS-REG-2007-00002), (2) Basis for Section 3116 Determination for Closure of F-Tank Farm at the Savannah River Site (DOE/SRS-WD-2012-001), (3) Tier 1 Closure Plan for the F-Area Waste Tank Systems at the Savannah River Site (SRR-CWDA-2010-00147), (4) F-Tank Farm Tanks 18 and 19 DOE Manual 435.1-1 Tier 2 Closure Plan Savannah River Site (SRR-CWDA-2011-00015), (5) Industrial Wastewater Closure Module for the Liquid Waste Tanks 18 and 19 (SRRCWDA-2010-00003), and (6) Tank 18/Tank 19 Special Analysis for the Performance Assessment for the F-Tank Farm at the Savannah River Site (hereafter referred to as the Tank 18/Tank 19 Special Analysis) (SRR-CWDA-2010-00124). Note that the first three FTF closure documents listed apply to the entire FTF, whereas the last three FTF closure documents listed are specific to Tanks 18 and 19. These two waste tanks are expected to be the first two tanks to be grouted and operationally closed under the current suite of FTF closure documents and many of the assumptions and approaches that apply to these two tanks are also applicable to the other FTF waste tanks and operational closure processes.

  5. Scale-4 Analysis of Pressurized Water Reactor Critical Configurations: Volume 5 - North Anna Unit 1 Cycle 5

    SciTech Connect

    Bowman, S.M.

    1993-01-01

    The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor (AFR) criticality safety analyses be validated against experimental measurements. If credit for the negative reactivity of the depleted (or spent) fuel isotopics is desired, it is necessary to benchmark computational methods against spent fuel critical configurations. This report summarizes a portion of the ongoing effort to benchmark AFR criticality analysis methods using selected critical configurations from commercial pressurized-water reactors (PWR). The analysis methodology selected for all calculations reported herein was the codes and data provided in the SCALE-4 code system. The isotopic densities for the spent fuel assemblies in the critical configurations were calculated using the SAS2H analytical sequence of the SCALE-4 system. The sources of data and the procedures for deriving SAS2H input parameters are described in detail. The SNIKR code module was used to extract the necessary isotopic densities from the SAS2H results and to provide the data in the format required by the SCALE criticality analysis modules. The CSASN analytical sequence in SCALE-4 was used to perform resonance processing of the cross sections. The KENO V.a module of SCALE-4 was used to calculate the effective multiplication factor (k{sub eff}) of each case. The SCALE-4 27-group burnup library containing ENDF/B-IV (actinides) and ENDF/B-V (fission products) data was used for all the calculations. This volume of the report documents the SCALE system analysis of one reactor critical configuration for North Anna Unit 1 Cycle 5. This unit and cycle were chosen for a previous analysis using a different methodology because detailed isotopics from multidimensional reactor calculations were available from the Virginia Power Company. These data permitted comparison of criticality calculations directly using the utility-calculated isotopics to those using the isotopics generated by the SCALE-4 SAS2H

  6. Empirical critical loads of atmospheric nitrogen deposition for nutrient enrichment and acidification of sensitive US lakes

    USGS Publications Warehouse

    Baron, J.S.; Driscoll, C.T.; Stoddard, J.L.; Richer, E.E.

    2011-01-01

    The ecological effects of elevated atmospheric nitrogen (N) deposition on high-elevation lakes of the western and northeastern United States include nutrient enrichment and acidification. The nutrient enrichment critical load for western lakes ranged from 1.0 to 3.0 kilograms (kg) of N per hectare (ha) per year, reflecting the nearly nonexistent watershed vegetation in complex, snowmelt-dominated terrain. The nutrient enrichment critical load for northeastern lakes ranged from 3.5 to 6.0 kg N per ha per year. The N acidification critical loads associated with episodic N pulses in waters with low values of acid neutralizing capacity were 4.0 kg N per ha per year (western) and 8.0 kg N per ha per year (northeastern). The empirical critical loads for N-caused acidification were difficult to determine because of a lack of observations in the West, and high sulfur deposition in the East. For both nutrient enrichment and acidification, the N critical load was a function of how atmospheric N deposition was determined. ?? 2011 by American Institute of Biological Sciences. All rights reserved.

  7. A novel modeling to predict the critical current behavior of Nb3Sn PIT strand under transverse load based on a scaling law and Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Wang, Tiening; Chiesa, Luisa; Takayasu, Makoto; Bordini, Bernardo

    2014-09-01

    Superconducting Nb3Sn Powder-In-Tube (PIT) strands could be used for the superconducting magnets of the next generation Large Hadron Collider. The strands are cabled into the typical flat Rutherford cable configuration. During the assembly of a magnet and its operation the strands experience not only longitudinal but also transverse load due to the pre-compression applied during the assembly and the Lorentz load felt when the magnets are energized. To properly design the magnets and guarantee their safe operation, mechanical load effects on the strand superconducting properties are studied extensively; particularly, many scaling laws based on tensile load experiments have been established to predict the critical current dependence on strain. However, the dependence of the superconducting properties on transverse load has not been extensively studied so far. One of the reasons is that transverse loading experiments are difficult to conduct due to the small diameter of the strand (about 1 mm) and the data currently available do not follow a common measurement standard making the comparison between different data sets difficult. Recently at the University of Geneva, a new device has been developed to characterize the critical current of Nb3Sn strands under transverse loads. In this work we present a new 2D Finite Element Analysis (FEA) to predict the electro-mechanical response of a PIT strand that was tested at the University of Geneva when transverse load is applied. The FEA provides the strain map for the superconducting filaments when the load is applied. Those strain maps are then used to evaluate the critical current behavior of a PIT strand using a recently developed scaling law that correlates the superconducting properties of a wire with the strain invariants due to the load applied on the superconductor. The benefits and limitations of this method are discussed based on the comparison between the critical current simulation results obtained with the filament

  8. Critical loads for lead in France: First results on forest soils

    NASA Astrophysics Data System (ADS)

    Probst, A.; Moncoulon, D.; Godderis, Y.; Hernandez, L.; Party, J.-P.

    2003-05-01

    Within the framework of the United Nation Convention on Long Range Transboundary Air Pollution, France is part of the Working Group on Effect which aims at evaluating the impact of atmospheric deposition on ecosystems by calculating critical loads. The “critical loads” are “the highest deposition of compounds that will not cause chemical changes in soil leading to long-term harmful effects on ecosystem structure and function”. A guidance manual for calculation of critical loads for heavy metals (lead and cadmium) has been proposed by the Coordination Center for Effects (executive body of the WGE). French National Focal Center (CNRS and ADEME) aims in this study at evaluating the accuracy of the european methodology for calculation of critical loads for french forest soils. It appears that critical load approach is adapted for France but need to be calibrated at least for calculation of weathering fluxes and determination of critical limits. Stand-still on the contrary is not adequate because of inherent contradictions in the method and too much uncertainties in the transfer functions.

  9. Highly loaded multi-stage fan drive turbine: Performance of final three configurations

    NASA Technical Reports Server (NTRS)

    Cherry, D. G.; Thomas, M. W.

    1974-01-01

    Results for a three-stage highly loaded fan drive turbine follow-on test program are presented. The effects of combinations of tandem and leaned bladerows on three-stage turbine performance were tested. The three-stage turbine with a tandem stator in stage two exhibited a total-to-total efficiency of approximately 0.887 as compared to 0.886 for the plain blade turbine base case.

  10. The scratch test - Different critical load determination techniques. [adhesive strength of thin hard coatings

    NASA Technical Reports Server (NTRS)

    Sekler, J.; Hintermann, H. E.; Steinmann, P. A.

    1988-01-01

    Different critical load determination techniques such as microscopy, acoustic emission, normal, tangential, and lateral forces used for scratch test evaluation of complex or multilayer coatings are investigated. The applicability of the scratch test to newly developed coating techniques, systems, and applications is discussed. Among the methods based on the use of a physical measurement, acoustic emission detection is the most effective. The dynamics ratio between the signals below and above the critical load for the acoustic emission (much greater than 100) is well above that obtained with the normal, tangential, and lateral forces. The present commercial instruments are limited in load application performance. A scratch tester able to apply accurate loads as low as 0.01 N would probably overcome most of the actual limitations and would be expected to extend the scratch testing technique to different application fields such as optics and microelectronics.

  11. Criticality Analysis for Proposed Maximum Fuel Loading in a Standardized SNF Canister with Type 1a Baskets

    SciTech Connect

    Chad Pope; Larry L. Taylor; Soon Sam Kim

    2007-02-01

    This document represents a summary version of the criticality analysis done to support loading SNF in a Type 1a basket/standard canister combination. Specifically, this engineering design file (EDF) captures the information pertinent to the intact condition of four fuel types with different fissile loads and their calculated reactivities. These fuels are then degraded into various configurations inside a canister without the presence of significant moderation. The important aspect of this study is the portrayal of the fuel degradation and its effect on the reactivity of a single canister given the supposition there will be continued moderation exclusion from the canister. Subsequent analyses also investigate the most reactive ‘dry’ canister in a nine canister array inside a hypothetical transport cask, both dry and partial to complete flooding inside the transport cask. The analyses also includes a comparison of the most reactive configuration to other benchmarked fuels using a software package called TSUNAMI, which is part of the SCALE 5.0 suite of software.

  12. Empirical critical loads of atmospheric nitrogen deposition for nutrient enrichment and acidification of sensitive US lakes

    NASA Astrophysics Data System (ADS)

    Baron, J.; Driscoll, C. T.; Stoddard, J. L.; Richer, E. E.

    2011-12-01

    Ecological effects of elevated atmospheric N deposition for high elevation lakes of the western and northeastern US include nutrient enrichment and acidification. These effects are most evident in high elevation lakes, which are sensitive to atmospheric deposition and have been minimally impacted by land disturbance. Nitrogen-limited lakes will exhibit increases in productivity and shifts in the composition of phytoplankton in response to increases in atmospheric N deposition. Wet N deposition reported by NADP/NTN does not accurately depict total N deposition including dry species, and national NADP maps can misrepresent total deposition amounts in regions of complex terrain, so we calculated N deposition three different ways in order to explore critical loads. The nutrient enrichment critical load for Western lakes ranged 1.0-3.0 kg N per ha per yr, reflecting near-lack of watershed vegetation in complex, snow-melt dominated terrain. The nutrient enrichment critical load for Northeastern lakes ranged 3.5-6.0 kg N per ha per yr. The N acidification critical loads associated with episodic N pulses in waters with low values of acid neutralizing capacity were 4.0 kg N per ha per yr (western) and 8.0 kg N per ha per yr (northeastern). Empirical critical loads for N-caused acidification were difficult to determine due to lack of observations in the West, and because of the additive effects of decades of atmospheric sulfur deposition in the Northeast. For both nutrient enrichment and acidification, the N critical load was a function of how atmospheric N deposition was determined.

  13. A New Mechanical Loading Configuration for Maximizing The Performance of Dielectric Elastomer Generators

    NASA Astrophysics Data System (ADS)

    Shian, Samuel; Huang, Jiangshui; Suo, Zhigang; Clarke, David

    2013-03-01

    Electrical energy can be generated from mechanical deformations using dielectric elastomers but currently achieved energy densities and conversion efficiencies are still small. In this presentation, we demonstrate that significant improvements, an energy density over 500 mJ/g and up to 10% in efficiency, can be produced using VHB elastomers by altering the mechanical loading geometry. A major limitation is viscous losses in the VHB elastomer indicating that higher efficiencies with other elastomers will be attainable. The basic concept of mechanical energy harvesting with a dielectric elastomer sheet is a straightforward electromechanical cycle leading to a voltage step-up: a sheet is stretched, electrical charge at low voltage is placed on either side using compliant electrodes, the stretch is released causing the sheet's initial thickness and area to be recovered increasing the charge potential which can then be harvested. Integral to maximizing the energy conversion is the amount of mechanical energy that can be stored elastically and the amount of capacitance change in the elastomer sheet during stretching. We show that these factors can be maximized by equi-biaxial loading. Details of our dielectric elastomer generator will be described as well as the procedures we use for quantifying its performance.

  14. Maximum-load predictions in the Dugdale model using critical CTOA criterion

    SciTech Connect

    Inhoy Gu . Dept. of Mechanical Engineering)

    1993-11-01

    An engineering method of elastic-plastic fracture analysis is suggested for plane-strain specimens under tension. The condition for an increment of crack extension is set by a critical increment of crack tip opening displacement (CTOD). The CTOD increment divided by the incremental crack extension is a critical crack tip opening angle (CTOA), assumed to be constant for a material of a given thickness, characterizing the tearing resistance of material. Based on a finite-element analysis of crack tip deformation, a load term in the CTOD equation of the Dugdale strip yield model is modified to accommodate large and small scale yielding, for which cohesive stress in the strip is assumed greater than that for the plane-stress model. Approximate generalization of the Dugdale model is suggested for finite-size specimens. A definition of CTOD is reviewed with a round and sharp crack tip. In a successive application of the CTOA is reviewed with a round and sharp crack tip. In a successive application of the CTOA criterion at a current extending crack tip, the integration of the incremental crack extensions and load increments after fracture initiation gives a relationship in which a maximum load is either a peak load or a limit load on an unbroken ligament. Material constants are evaluated so that the calculated loads agree with test loads at each crack extension. The proposed method is applied to various specimens of 304 stainless steel for which test data are available.

  15. Pressure loads and aerodynamic force information for the -89A space shuttle orbiter configuration, volume 2. [for structural strength analysis

    NASA Technical Reports Server (NTRS)

    Mennell, R. C.

    1973-01-01

    Experimental aerodynamic investigations were conducted on an 0.0405 scale representation of the Rockwell -89A Light Weight Space Shuttle Orbiter. The test purpose was to obtain pressure loads data in the presence of the ground for orbiter structural strength analysis. Aerodynamic force data was also recorded to allow correlation with all pressure loads information. Angles of attack from minus 3 deg to 18 deg and angles of sideslip of 0 deg, plus or minus 50 deg, and plus or minus 10 deg were tested in the presence of the NAAL ground plane. Static pressure bugs were used to obtain a pressure loads survey of the basic configuration, elevon deflections of 5 deg, 10 deg, 15 deg, and minus 20 deg and a rudder deflection of minus 15 deg, at a tunnel dynamic pressure of 40 psi. The test procedure was to locate a maximum of 30 static pressure bugs on the model surface at various locations calculated to prevent aerodynamic and physical interference. Then by various combinations of location the pressure bugs output was to define a complete pressure survey for the fuselages, wing, vertical tail, and main landing gear door.

  16. ESTIMATING CRITICAL LOADS OF SULFATE TO SURFACE WATERS IN THE NORTHEASTERN UNITED STATES

    EPA Science Inventory

    It is important to note that no attempt to evaluate or identify any of the results presented here as right/wrong, or to rank the reliability of results was made. he objective, rather, has been to generate sets of critical load estimates using multiple models and data sets, and to...

  17. NATIONAL CRITICAL LOADS FOR ATMOSPHERIC DEPOSITION EFFECTS ASSESSMENT: I. METHODS SUMMARY

    EPA Science Inventory

    The United State Environmental Protection Agency (EPA), with the assistance of the US Department of Energy (DOE) and the National Oceanographic and Atmospheric Admn (NOAA) is examining the utility of a critical loads approach for evaluating atmospheric pollutant effects on sensit...

  18. Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

    USGS Publications Warehouse

    Pardo, L.H.; Fenn, M.E.; Goodale, C.L.; Geiser, L.H.; Driscoll, C.T.; Allen, E.B.; Baron, J.S.; Bobbink, R.; Bowman, W.D.; Clark, C.M.; Emmett, B.; Gilliam, F.S.; Greaver, T.L.; Hall, S.J.; Lilleskov, E.A.; Liu, L.; Lynch, J.A.; Nadelhoffer, K.J.; Perakis, S.S.; Robin-Abbott, M. J.; Stoddard, J.L.; Weathers, K.C.; Dennis, R.L.

    2011-01-01

    Human activity in the last century has led to a significant increase in nitrogen (N) emissions and atmospheric deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the deposition of pollution that would be harmful to ecosystems is the determination of critical loads. A critical load is defined as the input of a pollutant below which no detrimental ecological effects occur over the long-term according to present knowledge. The objectives of this project were to synthesize current research relating atmospheric N deposition to effects on terrestrial and freshwater ecosystems in the United States, and to estimate associated empirical N critical loads. The receptors considered included freshwater diatoms, mycorrhizal fungi, lichens, bryophytes, herbaceous plants, shrubs, and trees. Ecosystem impacts included: (1) biogeochemical responses and (2) individual species, population, and community responses. Biogeochemical responses included increased N mineralization and nitrification (and N availability for plant and microbial uptake), increased gaseous N losses (ammonia volatilization, nitric and nitrous oxide from nitrification and denitrification), and increased N leaching. Individual species, population, and community responses included increased tissue N, physiological and nutrient imbalances, increased growth, altered root : shoot ratios, increased susceptibility to secondary stresses, altered fire regime, shifts in competitive interactions and community composition, changes in species richness and other measures of biodiversity, and increases in invasive species. The range of critical loads for nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1-39 kg N.ha -1.yr -1, spanning the range of N deposition observed over most of the country. The empirical critical loads for N tend to

  19. Criticality Safety Analysis Of As-loaded Spent Nuclear Fuel Casks

    SciTech Connect

    Banerjee, Kaushik; Scaglione, John M

    2015-01-01

    The final safety analysis report (FSAR) or the safety analysis report (SAR) for a particular spent nuclear fuel (SNF) cask system documents models and calculations used to demonstrate that a system meets the regulatory requirements under all normal, off-normal, and accident conditions of spent fuel storage, and normal and accident conditions of transportation. FSAR/SAR calculations and approved content specifications are intended to be bounding in nature to certify cask systems for a variety of fuel characteristics with simplified SNF loading requirements. Therefore, in general, loaded cask systems possess excess and uncredited criticality margins (i.e., the difference between the licensing basis and the as-loaded calculations). This uncredited margin could be quantified by employing more detailed cask-specific evaluations that credit the actual as-loaded cask inventory, and taking into account full (actinide and fission product) burnup credit. This uncredited criticality margin could be potentially used to offset (1) uncertainties in the safety basis that needs to account for the effects of system aging during extended dry storage prior to transportation, and (2) increases in SNF system reactivity over a repository performance period (e.g., 10,000 years or more) as the system undergoes degradation and internal geometry changes. This paper summarizes an assessment of cask-specific, as-loaded criticality margins for SNF stored at eight reactor sites (215 loaded casks were analyzed) under fully flooded conditions to assess the margins available during transportation after extended storage. It is observed that the calculated keff margin varies from 0.05 to almost 0.3 Δkeff for the eight selected reactor sites, demonstrating that significant uncredited safety margins are present. In addition, this paper evaluates the sufficiency of this excess margin in applications involving direct disposal of currently loaded SNF casks.

  20. STRUTEX: A prototype knowledge-based system for initially configuring a structure to support point loads in two dimensions

    NASA Technical Reports Server (NTRS)

    Robers, James L.; Sobieszczanski-Sobieski, Jaroslaw

    1989-01-01

    Only recently have engineers begun making use of Artificial Intelligence (AI) tools in the area of conceptual design. To continue filling this void in the design process, a prototype knowledge-based system, called STRUTEX has been developed to initially configure a structure to support point loads in two dimensions. This prototype was developed for testing the application of AI tools to conceptual design as opposed to being a testbed for new methods for improving structural analysis and optimization. This system combines numerical and symbolic processing by the computer with interactive problem solving aided by the vision of the user. How the system is constructed to interact with the user is described. Of special interest is the information flow between the knowledge base and the data base under control of the algorithmic main program. Examples of computed and refined structures are presented during the explanation of the system.

  1. STRUTEX: A prototype knowledge-based system for initially configuring a structure to support point loads in two dimensions

    NASA Technical Reports Server (NTRS)

    Rogers, James L.; Feyock, Stefan; Sobieszczanski-Sobieski, Jaroslaw

    1988-01-01

    The purpose of this research effort is to investigate the benefits that might be derived from applying artificial intelligence tools in the area of conceptual design. Therefore, the emphasis is on the artificial intelligence aspects of conceptual design rather than structural and optimization aspects. A prototype knowledge-based system, called STRUTEX, was developed to initially configure a structure to support point loads in two dimensions. This system combines numerical and symbolic processing by the computer with interactive problem solving aided by the vision of the user by integrating a knowledge base interface and inference engine, a data base interface, and graphics while keeping the knowledge base and data base files separate. The system writes a file which can be input into a structural synthesis system, which combines structural analysis and optimization.

  2. EVALUATION OF THE INITIAL CRITICAL CONFIGURATION OF THE HTR-10 PEBBLE-BED REACTOR

    SciTech Connect

    William K. Terry

    2005-11-01

    This report describes the evaluation of data from the initial criticality measurement of the HTR-10 pebble-bed reactor at the Institute of Nuclear Energy Technology in China to determine whether the data are of sufficient quality to use as benchmarks for reactor physics computer codes intended for pebble-bed reactor analysis. The evaluation applied the INL pebble-bed reactor physics code PEBBED to perform an uncertainty analysis on the core critical height. The overall uncertainty in k-effective was slightly over 0.5%, which is considered adequate for an experimental benchmark.

  3. 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.

  4. New approaches to provide ride-through for critical loads in electric power distribution systems

    NASA Astrophysics Data System (ADS)

    Montero-Hernandez, Oscar C.

    2001-07-01

    The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly

  5. A conceptual framework: redefining forest soil's critical acid loads under a changing climate.

    PubMed

    McNulty, Steven G; Boggs, Johnny L

    2010-06-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period

  6. Efficient identification of critical stresses in structures subject to dynamic loads

    NASA Technical Reports Server (NTRS)

    Haftka, R. T.; Watson, L. T.; Grandhi, R. V.

    1986-01-01

    Optimum structural design problems generally employ constraints which are parametric in terms of space and time variables. A parametric constraint may be replaced by equivalent critical point constraints at its local minima for optimization applications. In complex structures, accurate identification of such critical points is computationally expensive due to the cost of finite element analyses. Three techniques are described for efficiently and accurately identifying critical points for space- and time-dependent parametric constraints. An adaptive search technique and a spline interpolation technique are developed for exactly known response. A least squares spline approximation is suggested for noisy behavior. A helicopter tail-boom structure subjected to transient loading is used as an example to demonstrate the techniques described. All three techniques are shown to be computationally efficient for critical point identification and the least squares approximation also removes noise from the data. The case of multiple constraints per element is shown to be particularly suited to the use of spline techniques.

  7. Critical assessment of precracked specimen configuration and experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate

    NASA Technical Reports Server (NTRS)

    Domack, M. S.

    1985-01-01

    A research program was conducted to critically assess the effects of precracked specimen configuration, stress intensity solutions, compliance relationships and other experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate. Modified compact and double beam wedge-loaded specimens were tested and analyzed to determine the threshold stress intensity factor and stress corrosion crack growth rate. Stress intensity solutions and experimentally determined compliance relationships were developed and compared with other solutions available in the literature. Crack growth data suggests that more effective crack length measurement techniques are necessary to better characterize stress corrosion crack growth. Final load determined by specimen reloading and by compliance did not correlate well, and was considered a major source of interlaboratory variability. Test duration must be determined systematically, accounting for crack length measurement resolution, time for crack arrest, and experimental interferences. This work was conducted as part of a round robin program sponsored by ASTM committees G1.06 and E24.04 to develop a standard test method for stress corrosion testing using precracked specimens.

  8. CRITICALITY CALCULATION FOR THE MOST REACTIVE DEGRADED CONFIGURATIONS OF THE FFTF SNF CODISPOSAL WP CONTAINING AN INTACT IDENT-69 CONTAINER

    SciTech Connect

    D.R. Moscalu

    2002-08-28

    The objective of this calculation is to perform additional degraded mode criticality evaluations of the Department of Energy's (DOE) Fast Flux Test Facility (FFTF) Spent Nuclear Fuel (SNF) codisposed in a 5-Defense High-Level Waste (5-DHLW) Waste Package (WP). The scope of this calculation is limited to the most reactive degraded configurations of the codisposal WP with an almost intact Ident-69 container (breached and flooded but otherwise non-degraded) containing intact FFTF SNF pins. The configurations have been identified in a previous analysis (CRWMS M&O 1999a) and the present evaluations include additional relevant information that was left out of the original calculations. The additional information describes the exact distribution of fissile material in each container (DOE 2002a). The effects of the changes that have been included in the baseline design of the codisposal WP (CRWMS M&O 2000) are also investigated. The calculation determines the effective neutron multiplication factor (k{sub eff}) for selected degraded mode internal configurations of the codisposal waste package. These calculations will support the demonstration of the technical viability of the design solution adopted for disposing of MOX (FFTF) spent nuclear fuel in the potential repository. This calculation is subject to the Quality Assurance Requirements and Description (QARD) (DOE 2002b) per the activity evaluation under work package number P6212310M2 in the technical work plan TWP-MGR-MD-000010 REV 01 (BSC 2002).

  9. Environmental burden of acid gas emissions associated with the exceedence of critical loads

    NASA Astrophysics Data System (ADS)

    Fisher, Bernard E. A.

    This paper demonstrates an approach to assessing environmental burdens based on optimising the integrated deposition footprints of characteristic sources, such as power stations, urban areas or poultry farms, relative to 1 km×1 km ecosystem-dependent critical loads. It makes use of a penalty function and an adjoint Green's function method describing how the deposition of acid gases and reduced nitrogen compounds compare with critical loads, from which the optimum source location in Great Britain may be found. The effect of a unit of emission from a source category can be described on a single map. This simple risk based approach to environmental burdens is compared to a more elaborate optimisation, using large combustion plant emissions as an example.

  10. Critical-load studies of a shield support. Report of investigations/1987

    SciTech Connect

    Barczak, T.M.; Schwemmer, D.E.

    1987-01-01

    One of the primary goals of Bureau of Mines research is to reduce the cost of coal mining by improving the efficiency of longwall supports. One method of achieving the goal is the optimization of stress distribution within the support structure, resulting in a lower overall weight, more fully stressed shield. However, before stress optimization can be initiated, load conditions must be defined that cause maximum stress in the various support components. A finite-element model of a longwall shield was used to identify these critical load conditions. These load conditions were then evaluated in the Bureau's mine roof simulator by instrumentation of a longwall shield and measurement of strains in each of the shield components.

  11. Critical loads and the relevance of ammonia to an effects-based nitrogen protocol

    NASA Astrophysics Data System (ADS)

    Bull, K. R.; Sutton, M. A.

    With the signing of the Second Sulphur Protocol in Oslo in 1994, many countries indicated their willingness to adopt an effects-based approach to reducing pollutant emissions. Current activities under the UNECE Convention on Long-Range Transboundary Air Pollution have now moved to revision of the NO x Protocol. Because of the complex interaction of NO x with other pollutants, a "multi-pollutant, multi-effect" approach is envisaged, taking into account emissions of total reactive N (as NO x and NH 3), and considering acidification, nutrient N and photochemical oxidant effects. The magnitude of NH 3 emissions and deposition of NH x at an international scale have necessitated that NH 3 be considered. Adoption of an effects-based approach for NH 3 demands much information regarding the quantification of emissions and deposition, the understanding of physicochemical and biological processes for estimating critical loads, and the assessment of effectiveness and costs of emission abatement measures. In addition, methodology is needed to enable abatement strategies to be developed for SO 2, NO x and NH 3 at the same time. For the Second S Protocol, an approach defining the "S fraction" ( Sf) of acidity critical loads was used to distinguish S and N effects. Besides being difficult to justify scientifically, the dependence of Sf on "current" deposition results in changing critical loads as deposition is reduced. Current work under the Convention uses a "critical loads function", which considers S and N deposition simultaneously, for both acidification and eutrophication. This approach, together with the integrated assessment models approach used for the S Protocol, is achieving some of the multi-pollutant goals, though because of the link of emissions to environmental impacts, ongoing scientific underpinning and improved data remain essential.

  12. Nitrogen Critical Loads for an Alpine Meadow Ecosystem on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zong, Ning; Shi, Peili; Song, Minghua; Zhang, Xianzhou; Jiang, Jing; Chai, Xi

    2016-03-01

    Increasing atmospheric nitrogen (N) deposition has the potential to alter plant diversity and thus the function and stability of terrestrial ecosystems. N-limited alpine ecosystems are expected to be particularly susceptible to increasing N deposition. However, little is known about the critical loads and saturation thresholds of ecosystem responses to increasing N deposition on the Tibetan Plateau, despite its importance to ecosystem management. To evaluate the N critical loads and N saturation thresholds in an alpine ecosystem, in 2010, we treated an alpine meadow with five levels of N addition (0, 10, 20, 40, and 80 kg N ha-1 year-1) and characterized plant and soil responses. The results showed that plant species richness and diversity index did not statistically vary with N addition treatments, but they both changed with years. N addition affected plant cover and aboveground productivity, especially for grasses, and soil chemical features. The N critical loads and saturation thresholds, in terms of plant cover and biomass change at the community level, were 8.8-12.7 and 50 kg N ha-1 year-1 (including the ambient N deposition rate), respectively. However, pronounced changes in soil inorganic N and net N mineralization occurred under the 20 and 40 kg N ha-1 year-1 treatments. Our results indicate that plant community cover and biomass are more sensitive than soil to increasing N inputs. The plant community composition in alpine ecosystems on the Qinghai-Tibetan Plateau may change under increasing N deposition in the future.

  13. Nitrogen Critical Loads for an Alpine Meadow Ecosystem on the Tibetan Plateau.

    PubMed

    Zong, Ning; Shi, Peili; Song, Minghua; Zhang, Xianzhou; Jiang, Jing; Chai, Xi

    2016-03-01

    Increasing atmospheric nitrogen (N) deposition has the potential to alter plant diversity and thus the function and stability of terrestrial ecosystems. N-limited alpine ecosystems are expected to be particularly susceptible to increasing N deposition. However, little is known about the critical loads and saturation thresholds of ecosystem responses to increasing N deposition on the Tibetan Plateau, despite its importance to ecosystem management. To evaluate the N critical loads and N saturation thresholds in an alpine ecosystem, in 2010, we treated an alpine meadow with five levels of N addition (0, 10, 20, 40, and 80 kg N ha(-1) year(-1)) and characterized plant and soil responses. The results showed that plant species richness and diversity index did not statistically vary with N addition treatments, but they both changed with years. N addition affected plant cover and aboveground productivity, especially for grasses, and soil chemical features. The N critical loads and saturation thresholds, in terms of plant cover and biomass change at the community level, were 8.8-12.7 and 50 kg N ha(-1) year(-1) (including the ambient N deposition rate), respectively. However, pronounced changes in soil inorganic N and net N mineralization occurred under the 20 and 40 kg N ha(-1) year(-1) treatments. Our results indicate that plant community cover and biomass are more sensitive than soil to increasing N inputs. The plant community composition in alpine ecosystems on the Qinghai-Tibetan Plateau may change under increasing N deposition in the future. PMID:26475686

  14. Unsteady loads due to propulsive lift configurations. Part D: The development of an experimental facility for the investigation of scaling effects on propulsive lift configurations

    NASA Technical Reports Server (NTRS)

    Haviland, J. K.; Herling, W. W.

    1978-01-01

    The design and construction of an experimental facility for the investigation of scaling effects in propulsive lift configurations are described. The facility was modeled after an existing full size NASA facility which consisted of a coaxial turbofan jet engine with a rectangular nozzle in a blown surface configuration. The flow field of the model facility was examined with and without a simulated wing surface in place at several locations downstream of the nozzle exit plane. Emphasis was placed on obtaining pressure measurements which were made with static probes and surface pressure ports connected via plastic tubing to condenser microphones for fluctuating measurements. Several pressure spectra were compared with those obtained from the NASA facility, and were used in a preliminary evaluation of scaling laws.

  15. Atmospheric Deposition and Critical Loads for Nitrogen and Metals in Arctic Alaska: Review and Current Status

    USGS Publications Warehouse

    Linder, Greg L.; Brumbaugh, William G.; Neitlich, Peter; Little, Edward

    2013-01-01

    To protect important resources under their bureau’s purview, the United States National Park Service’s (NPS) Arctic Network (ARCN) has developed a series of “vital signs” that are to be periodically monitored. One of these vital signs focuses on wet and dry deposition of atmospheric chemicals and further, the establishment of critical load (CL) values (thresholds for ecological effects based on cumulative depositional loadings) for nitrogen (N), sulfur, and metals. As part of the ARCN terrestrial monitoring programs, samples of the feather moss Hylocomium splendens are being col- lected and analyzed as a cost-effective means to monitor atmospheric pollutant deposition in this region. Ultimately, moss data combined with refined CL values might be used to help guide future regulation of atmospheric contaminant sources potentially impacting Arctic Alaska. But first, additional long-term studies are needed to determine patterns of contaminant deposition as measured by moss biomonitors and to quantify ecosystem responses at particular loadings/ ranges of contaminants within Arctic Alaska. Herein we briefly summarize 1) current regulatory guidance related to CL values 2) derivation of CL models for N and metals, 3) use of mosses as biomonitors of atmospheric deposition and loadings, 4) preliminary analysis of vulnerabilities and risks associated with CL estimates for N, 5) preliminary analysis of existing data for characterization of CL values for N for interior Alaska and 6) implications for managers and future research needs.

  16. New Colistin Population Pharmacokinetic Data in Critically Ill Patients Suggesting an Alternative Loading Dose Rationale

    PubMed Central

    Grégoire, N.; Mimoz, O.; Mégarbane, B.; Comets, E.; Chatelier, D.; Lasocki, S.; Gauzit, R.; Balayn, D.; Gobin, P.; Marchand, S.

    2014-01-01

    Colistin is an old antibiotic that has recently gained a considerable renewal of interest as the last-line defense therapy against multidrug-resistant Gram-negative bacteria. It is administered as colistin methanesulfonate (CMS), an inactive prodrug, and it was shown that due to slow CMS conversion, colistin plasma concentrations increase very slowly after treatment initiation, which constitutes the rationale for a loading dose in critically ill patients. However, faster CMS conversion was observed in healthy volunteers but using a different CMS brand, which may also have a major impact on colistin pharmacokinetics. Seventy-three critically ill patients not undergoing dialysis received multiple doses of CMS. The CMS concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a pharmacokinetic analysis was conducted using a population approach. We confirmed that CMS renal clearance and colistin concentrations at steady state are mostly governed by creatinine clearance, but we predict a typical maximum concentration of drug in serum (Cmax) of colistin close to 2 mg/liter, occurring 3 h after an initial dose of 2 million international units (MIU) of CMS. Accordingly, the estimated colistin half-life (t1/2) was relatively short (3.1 h), with rapid attainment of steady state. Our results are only partially consistent with other recently published results. We confirm that the CMS maintenance dose should be adjusted according to renal function in critically ill patients. However, much higher than expected colistin concentrations were observed after the initial CMS dose, with rapid steady-state achievement. These discrepancies challenge the pharmacokinetic rationale for a loading dose, which may still be appropriate for rapid bacterial eradication and an improved clinical cure rate. PMID:25267662

  17. New colistin population pharmacokinetic data in critically ill patients suggesting an alternative loading dose rationale.

    PubMed

    Grégoire, N; Mimoz, O; Mégarbane, B; Comets, E; Chatelier, D; Lasocki, S; Gauzit, R; Balayn, D; Gobin, P; Marchand, S; Couet, W

    2014-12-01

    Colistin is an old antibiotic that has recently gained a considerable renewal of interest as the last-line defense therapy against multidrug-resistant Gram-negative bacteria. It is administered as colistin methanesulfonate (CMS), an inactive prodrug, and it was shown that due to slow CMS conversion, colistin plasma concentrations increase very slowly after treatment initiation, which constitutes the rationale for a loading dose in critically ill patients. However, faster CMS conversion was observed in healthy volunteers but using a different CMS brand, which may also have a major impact on colistin pharmacokinetics. Seventy-three critically ill patients not undergoing dialysis received multiple doses of CMS. The CMS concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a pharmacokinetic analysis was conducted using a population approach. We confirmed that CMS renal clearance and colistin concentrations at steady state are mostly governed by creatinine clearance, but we predict a typical maximum concentration of drug in serum (Cmax) of colistin close to 2 mg/liter, occurring 3 h after an initial dose of 2 million international units (MIU) of CMS. Accordingly, the estimated colistin half-life (t1/2) was relatively short (3.1 h), with rapid attainment of steady state. Our results are only partially consistent with other recently published results. We confirm that the CMS maintenance dose should be adjusted according to renal function in critically ill patients. However, much higher than expected colistin concentrations were observed after the initial CMS dose, with rapid steady-state achievement. These discrepancies challenge the pharmacokinetic rationale for a loading dose, which may still be appropriate for rapid bacterial eradication and an improved clinical cure rate. PMID:25267662

  18. Influence of the heater material on the critical heat load at boiling of liquids on surfaces with different sizes

    NASA Astrophysics Data System (ADS)

    Anokhina, E. V.

    2010-05-01

    Data on critical heat loads q cr for the saturated and unsaturated pool boiling of water and ethanol under atmospheric pressure are reported. It is found experimentally that the critical heat load does not necessarily coincide with the heat load causing burnout of the heater, which should be taken into account. The absolute values of q cr for the boiling of water and ethanol on copper surfaces 65, 80, 100, 120, and 200 μm in diameter; tungsten surface 100 μm in diameter; and nichrome surface 100 μm in diameter are obtained experimentally.

  19. Aerothermal loads analysis for high speed flow over a quilted surface configuration. [metallic Thermal Protection System panels simulation for Space Shuttle

    NASA Technical Reports Server (NTRS)

    Olsen, G. C.; Smith, R. E.

    1984-01-01

    Attention is given to hypersonic laminar flow over a quilted surface configuration that simulates an array of Space Shuttle Thermal Protection System panels bowed in a spherical shape as a result of thermal gradients through the panel thickness. Pressure and heating loads to the surface are determined. The flow field over the configuration was mathematically modeled by means of time-dependent, three-dimensional conservation of mass, momentum, and energy equations. A boundary mapping technique was then used to obtain a rectangular, parallelepiped computational domain, and an explicit MacCormack (1972) explicit time-split predictor-corrector finite difference algorithm was used to obtain steady state solutions. Total integrated heating loads vary linearly with bowed height when this value does not exceed the local boundary layer thickness.

  20. Nitrogen critical loads and management alternatives for N-impacted ecosystems in California.

    PubMed

    Fenn, M E; Allen, E B; Weiss, S B; Jovan, S; Geiser, L H; Tonnesen, G S; Johnson, R F; Rao, L E; Gimeno, B S; Yuan, F; Meixner, T; Bytnerowicz, A

    2010-12-01

    Empirical critical loads for N deposition effects and maps showing areas projected to be in exceedance of the critical load (CL) are given for seven major vegetation types in California. Thirty-five percent of the land area for these vegetation types (99,639 km(2)) is estimated to be in excess of the N CL. Low CL values (3-8 kg N ha(-1) yr(-1)) were determined for mixed conifer forests, chaparral and oak woodlands due to highly N-sensitive biota (lichens) and N-poor or low biomass vegetation in the case of coastal sage scrub (CSS), annual grassland, and desert scrub vegetation. At these N deposition critical loads the latter three ecosystem types are at risk of major vegetation type change because N enrichment favors invasion by exotic annual grasses. Fifty-four and forty-four percent of the area for CSS and grasslands are in exceedance of the CL for invasive grasses, while 53 and 41% of the chaparral and oak woodland areas are in exceedance of the CL for impacts on epiphytic lichen communities. Approximately 30% of the desert (based on invasive grasses and increased fire risk) and mixed conifer forest (based on lichen community changes) areas are in exceedance of the CL. These ecosystems are generally located further from emissions sources than many grasslands or CSS areas. By comparison, only 3-15% of the forested and chaparral land areas are estimated to be in exceedance of the NO(3)(-) leaching CL. The CL for incipient N saturation in mixed conifer forest catchments was 17 kg N ha(-1) yr(-1). In 10% of the CL exceedance areas for all seven vegetation types combined, the CL is exceeded by at least 10 kg N ha(-1) yr(-1), and in 27% of the exceedance areas the CL is exceeded by at least 5 kg N ha(-1) yr(-1). Management strategies for mitigating the effects of excess N are based on reducing N emissions and reducing site N capital through approaches such as biomass removal and prescribed fire or control of invasive grasses by mowing, selective herbicides, weeding or

  1. 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

  2. Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

    USGS Publications Warehouse

    Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

    2012-01-01

    Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (-1 yr-1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha-1 yr-1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha-1 yr-1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO3- threshold at which ecological effects are thought to occur. Based on an NO3- threshold of 0.5 μmol L-1, N deposition exceeds CLNdep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

  3. Empirical and modeling approaches to setting critical loads for N deposition in southern California shrublands

    NASA Astrophysics Data System (ADS)

    Allen, E. B.; Rao, L. E.; Fenn, M. E.; Bytnerowicz, A.; Tonnesen, G.

    2008-12-01

    Southern California deserts and coastal sage scrub (CSS) are undergoing vegetation-type conversion to exotic annual grassland, especially in regions downwind of urban areas that receive high N, primarily as dry deposition. To determine critical loads (CL) of N that cause negative impacts, we measured plant and soil responses along N deposition gradients, fertilized vegetation at different N levels, and used biomass production output from the DayCent model. N deposition gradients were identified from the CMAQ model and compared with measured N deposition values. CSS receives N deposition as high as 30 kg ha-1yr- 1, while the desert has levels up to 16 kg ha-1yr-1. Unlike more mesic ecosystems where critical loads are determined by changes in soil chemistry or biogeocycling, these arid and semiarid ecosystems are subject to increases in exotic species production, loss of native species diversity, and increased fire risk at relatively low CL's for N of 5 - 10 kg ha-1yr-1. For instance, a gradient survey in CSS showed that exotic grass increased and native plant species and arbuscular mycorrhizal species richness declined by almost half above 11 kg N ha-1yr-1. Fertilization studies in desert creosote bush scrub showed a significant increase in exotic species biomass with 5 kg N ha-1yr-1 in a wet year, and biomass output from DayCent modeling indicated an increased fire risk from exotic grasses with 1 T per ha production during years with moderate to high precipitation at 5 kg N ha-1yr-1. The difference in CL between desert and CSS may be related to the responsiveness of native vs. exotic plant species to N, as well as the degree to which precipitation and soil N limits plant growth in the two vegetation types.

  4. Empirical and simulated critical loads for nitrogen deposition in California mixed conifer forests.

    PubMed

    Fenn, M E; Jovan, S; Yuan, F; Geiser, L; Meixner, T; Gimeno, B S

    2008-10-01

    Empirical critical loads (CL) for N deposition were determined from changes in epiphytic lichen communities, elevated NO(3)(-) leaching in streamwater, and reduced fine root biomass in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at sites with varying N deposition. The CL for lichen community impacts of 3.1 kg ha(-1) year(-1) is expected to protect all components of the forest ecosystem from the adverse effects of N deposition. Much of the western Sierra Nevada is above the lichen-based CL, showing significant changes in lichen indicator groups. The empirical N deposition threshold and that simulated by the DayCent model for enhanced NO(3)(-)leaching were 17 kg N ha(-1) year(-1). DayCent estimated that elevated NO(3)(-) leaching in the San Bernardino Mountains began in the late 1950s. Critical values for litter C:N (34.1), ponderosa pine foliar N (1.1%), and N concentrations (1.0%) in the lichen Letharia vulpina ((L.) Hue) are indicative of CL exceedance. PMID:18499320

  5. A Simulation Study to Explore Configuring the New SAT® Critical Reading Section without Analogy Items. Research Report No. 2004-2. ETS RR-04-01

    ERIC Educational Resources Information Center

    Liu, Jinghua; Feigenbaum, Miriam; Cook, Linda

    2004-01-01

    This study explored possible configurations of the new SAT® critical reading section without analogy items. The item pool contained items from SAT verbal (SAT-V) sections of 14 previously administered SAT tests, calibrated using the three-parameter logistic IRT model. Multiple versions of several prototypes that do not contain analogy items were…

  6. Critical nitrogen deposition loads in high-elevation lakes of the western US inferred from paleolimnological records

    USGS Publications Warehouse

    Saros, J.E.; Clow, D.W.; Blett, T.; Wolfe, A.P.

    2011-01-01

    Critical loads of nitrogen (N) from atmospheric deposition were determined for alpine lake ecosystems in the western US using fossil diatom assemblages in lake sediment cores. Changes in diatom species over the last century were indicative of N enrichment in two areas, the eastern Sierra Nevada, starting between 1960 and 1965, and the Greater Yellowstone Ecosystem, starting in 1980. In contrast, no changes in diatom community structure were apparent in lakes of Glacier National Park. To determine critical N loads that elicited these community changes, we modeled wet nitrogen deposition rates for the period in which diatom shifts first occurred in each area using deposition data spanning from 1980 to 2007. We determined a critical load of 1.4 kg N ha-1 year-1 wet N deposition to elicit key nutrient enrichment effects on diatom communities in both the eastern Sierra Nevada and the Greater Yellowstone Ecosystem. ?? 2010 Springer Science+Business Media B.V.

  7. INFUENCE OF SPECIMEN TYPE AND LOADING CONFIGURATION ON THE FRACTURE STRENGTH OF SiC LAYER IN COATED PARTICLE FUEL

    SciTech Connect

    Byun, Thak Sang; Hong, Seong Gu; Katoh, Yutai; Snead, Lance Lewis

    2006-01-01

    Internal pressurization and diametrical loading techniques were developed to measure the fracture strength of the chemical vapor deposition (CVD) silicon carbide (SiC) coatings in nuclear fuel particles. Miniature tubular and hemispherical shell specimens were used for both test methods. In the internal pressurization test an expansion load was applied to the inner surface of a specimen by use of a compressively loaded elastomeric insert (polyurethane). In the crush test a diametrical compressive load was applied to the outer surface(s) of a specimen. The test results revealed that the fracture strengths from four test methods obeyed Weibull's two-parameter distribution, and the measured values of the Weibull modulus were consistent for different test methods. The fracture strengths measured by crush test techniques were larger than those by internal pressurization tests. This is because the internal pressurization produces uniform stress distribution while the diametrical loading technique produces severely localized stress distribution. The test method dependence of fracture strength was explained by the size effect predicted by effective surface.

  8. Critical Configuration and Physics Measurements for Assemblies of U(93.15)O2 Fuel Rods (1.506-cm Pitch)

    SciTech Connect

    Margaret A. Marshall

    2013-03-01

    A series of critical experiments were completed from 1962–1965 at Oak Ridge National Laboratory’s (ORNL’s) Critical Experiments Facility (CEF) in support of the Medium-Power Reactor Experiments (MPRE) program. In the late 1950s, efforts were made to study “power plants for the production of electrical power in space vehicles.”(a) The MPRE program was a part of those efforts and studied the feasibility of a stainless-steel system, boiling potassium 1 MW(t), or about 140 kW(e), reactor. The program was carried out in [fiscal years] 1964, 1965, and 1966. A summary of the program’s effort was compiled in 1967.a The delayed critical experiments were a mockup of a small, potassium-cooled space power reactor for validation of reactor calculations and reactor physics methods. Initial experiments, performed in November and December of 1962, consisted of a core of unmoderated stainless-steel tubes, each containing 26 UO2 fuel pellets, surrounded by a graphite reflector. Measurements were performed to determine critical reflector arrangements, relative fission-rate distributions, and cadmium ratio distributions. Subsequent experiments used beryllium reflectors and also measured the reactivity for various materials placed in the core. “The [assemblies were built] on [a] vertical assembly machine so that the movable part was the core and bottom reflector” (see Reference 1). The experiment studied in this evaluation was the second of the series and had the fuel rods in a 1.506-cm-triangular pitch. One critical configuration was found (see Reference 3). Once the critical configuration had been achieved, various measurements of reactivity, relative axial and radial activation rates of 235U,bc and cadmium ratios were performed. The cadmium ratio, reactivity, and activation rate measurements performed on the critical configuration are described in Sections 1.3, 1.4, and 1.7, respectively.

  9. Ecological risk assessment of acidification in the Northern Eurasia using critical load concept

    SciTech Connect

    Bashkin, V.; Golinets, O.

    1995-12-31

    This research presents the risk analysis of acid forming compounds input using critical loads (CL) values of sulfur, nitrogen, and acidity under the computer calculations for terrestrial and freshwater ecosystems of Northern Eurasia. The Cl values are used to set goals for future deposition rates of acidifying and eutrophication compounds so that the environment is protected. CL values for various ecosystems are determined using EM GIS approach. The most influential sources, such as nitrogen, sulfur and base cations uptake by vegetation, surface and groundwater leaching from terrestrial to freshwater ecosystems are described for the whole territory under study regarding uncertainty analysis and the level of corresponding risk assessment. This may be explained by many factors of which the most important are: the estimation of plant uptake is carried out on the basis of data on the biogeochemical cycling of various elements, for which adequate quantitative characterization for all ecosystems under study is either absent or insufficient; reliable information on the quantitative assessment of the ratio between perennial plant biomes increase and dead matter is absent for the required level of spatial and temporal resolution; reliable data on surface and underground runoff in various ecosystems are rare; the influence of hydrothermic factors on the above mentioned processes has not been quantitatively determined at required level of model resolution.

  10. Optical feather and foil for shape and dynamic load sensing of critical flight surfaces

    NASA Astrophysics Data System (ADS)

    Black, Richard J.; Costa, Joannes M.; Faridian, Fereydoun; Moslehi, Behzad; Pakmehr, Mehrdad; Schlavin, Jon; Sotoudeh, Vahid; Zagrai, Andrei

    2014-04-01

    Future flight vehicles may comprise complex flight surfaces requiring coordinated in-situ sensing and actuation. Inspired by the complexity of the flight surfaces on the wings and tail of a bird, it is argued that increasing the number of interdependent flight surfaces from just a few, as is normal in an airplane, to many, as in the feathers of a bird, can significantly enlarge the flight envelope. To enable elements of an eco-inspired Dynamic Servo-Elastic (DSE) flight control system, IFOS is developing a multiple functionality-sensing element analogous to a feather, consisting of a very thin tube with optical fiber based strain sensors and algorithms for deducing the shape of the "feather" by measuring strain at multiple points. It is envisaged that the "feather" will act as a unit of sensing and/or actuation for establishing shape, position, static and dynamic loads on flight surfaces and in critical parts. Advanced sensing hardware and software control algorithms will enable the proposed DSE flight control concept. The hardware development involves an array of optical fiber based sensorized needle tubes for attachment to key parts for dynamic flight surface measurement. Once installed the optical fiber sensors, which can be interrogated over a wide frequency range, also allow damage detection and structural health monitoring.

  11. Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

    USGS Publications Warehouse

    Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

    2012-01-01

    Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (−1 yr−1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha−1 yr−1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha−1 yr−1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO3− threshold at which ecological effects are thought to occur. Based on an NO3− threshold of 0.5 μmol L−1, N deposition exceeds CLNdep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

  12. Use of Combined Biogeochemical Model Approaches and Empirical Data to Assess Critical Loads of Nitrogen

    SciTech Connect

    Fenn, Mark E.; Driscoll, Charles; Zhou, Qingtao; Rao, Leela E.; Meixner, Tom; Allen, Edith B.; Yuan, Fengming; Sullivan, Timothy J.

    2015-01-01

    Empirical and dynamic biogeochemical modelling are complementary approaches for determining the critical load (CL) of atmospheric nitrogen (N) or other constituent deposition that an ecosystem can tolerate without causing ecological harm. The greatest benefits are obtained when these approaches are used in combination. Confounding environmental factors can complicate the determination of empirical CLs across depositional gradients, while the experimental application of N amendments for estimating the CL does not realistically mimic the effects of chronic atmospheric N deposition. Biogeochemical and vegetation simulation models can provide CL estimates and valuable ecosystem response information, allowing for past and future scenario testing with various combinations of environmental factors, pollutants, pollutant control options, land management, and ecosystem response parameters. Even so, models are fundamentally gross simplifications of the real ecosystems they attempt to simulate. Empirical approaches are vital as a check on simulations and CL estimates, to parameterize models, and to elucidate mechanisms and responses under real world conditions. In this chapter, we provide examples of empirical and modelled N CL approaches in ecosystems from three regions of the United States: mixed conifer forest, desert scrub and pinyon- juniper woodland in California; alpine catchments in the Rocky Mountains; and lakes in the Adirondack region of New York state.

  13. Effects of method of loading and specimen configuration on compressive strength of graphite/epoxy composite materials

    NASA Technical Reports Server (NTRS)

    Clark, R. K.; Lisagor, W. B.

    1980-01-01

    Three test schemes were examined for testing graphite/epoxy (Narmco T300/5208) composite material specimens to failure in compression, including an adaptation of the IITRI "wedge grip" compression fixture, a face-supported-compression fixture, and an end-loaded-coupon fixture. The effects of specimen size, specimen support arrangement and method of load transfer on compressive behavior of graphite/epoxy were investigated. Compressive stress strain, strength, and modulus data obtained with the three fixtures are presented with evaluations showing the effects of all test parameters, including fiber orientation. The IITRI fixture has the potential to provide good stress/strain data to failure for unidirectional and quasi-isotropic laminates. The face supported fixture was found to be the most desirable for testing + or - 45 s laminates.

  14. Slow Crack Growth Behavior and Life/Reliability Analysis of 96 wt % Alumina at Ambient Temperature With Various Specimen/Loading Configurations

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Powers, Lynn M.; Nemeth, Noel N.

    2000-01-01

    Extensive constant stress-rate testing for 96 wt % alumina was conducted in room-temperature distilled water using four different specimen/loading configurations: rectangular beam test specimens under four-point uniaxial flexure, square plate test specimens in ring-on-ring biaxial flexure, square plate test specimens in ball-on-ring biaxial flexure, and dog-boned tensile test specimens in pure tension. The slow crack growth (SCG) parameter n was almost independent of specimen/loading configurations, in either four-point uniaxial flexure, ring-on-ring biaxial flexure, ball-on-ring biaxial flexure, or pure tension, ranging from n = 35 to 47 with an average value of n = 41.1 +/- 4.5. The prediction of fatigue strength/reliability based on the four-point uniaxial flexure data by using the CARES/Life design code as well as a simple PIA model was in good agreement with both the ring-on-ring biaxial and the ball-on-ring biaxial flexure data. A poor prediction using the PIA model was observed for the dog-boned tensile test specimens, presumably due to different flaw population involved in the tensile test specimens.

  15. Present and future nitrogen deposition to national parks in the United States: critical load exceedances

    NASA Astrophysics Data System (ADS)

    Ellis, R. A.; Jacob, D. J.; Payer, M.; Zhang, L.; Holmes, C. D.; Schichtel, B. A.; Blett, T.; Porter, E.; Pardo, L. H.; Lynch, J. A.

    2013-04-01

    National parks in the United States are protected areas wherein the natural habitat is to be conserved for future generations. Deposition of anthropogenic nitrogen (N) transported from areas of human activity (fuel combustion, agriculture) may affect these natural habitats if it exceeds an ecosystem-dependent critical load (CL). We quantify and interpret the deposition to Class I US national parks for present-day and future (2050) conditions using the GEOS-Chem global chemical transport model with 1/2° × 2/3° horizontal resolution over North America. We estimate CL values in the range 2.5-5 kg N ha-1 yr-1 for the different parks with the goal of protecting the most sensitive ecosystem receptors. For present-day conditions, we find 24 out of 45 parks to be in CL exceedance and 14 more to be marginally so. Many of these are in remote areas of the West. Most (40-85%) of the deposition originates from NOx emissions (fuel combustion). We then project future changes in N deposition using the Representative Concentration Pathway (RCP) emission scenarios for 2050. These feature 52-73% declines in US NOx emissions relative to present but 19-50% increases in US ammonia (NH3) emissions. Nitrogen deposition at US national parks then becomes dominated by domestic NH3 emissions. While deposition decreases in the East relative to present, there is little progress in the West and increases in some regions. We find that 17-25 US national parks will have CL exceedances in 2050 based on the RCP scenarios. Even in total absence of anthropogenic NOx emissions, 14-18 parks would still have a CL exceedance. Returning all parks to N deposition below CL by 2050 will require at least a 55% decrease in anthropogenic NH3 emissions relative to RCP-projected 2050 levels.

  16. Present and future nitrogen deposition to national parks in the United States: critical load exceedances

    NASA Astrophysics Data System (ADS)

    Ellis, R. A.; Jacob, D. J.; Sulprizio, M. P.; Zhang, L.; Holmes, C. D.; Schichtel, B. A.; Blett, T.; Porter, E.; Pardo, L. H.; Lynch, J. A.

    2013-09-01

    National parks in the United States are protected areas wherein the natural habitat is to be conserved for future generations. Deposition of anthropogenic nitrogen (N) transported from areas of human activity (fuel combustion, agriculture) may affect these natural habitats if it exceeds an ecosystem-dependent critical load (CL). We quantify and interpret the deposition to Class I US national parks for present-day and future (2050) conditions using the GEOS-Chem global chemical transport model with 1/2° × 2/3° horizontal resolution over North America. We estimate CL values in the range 2.5-5 kg N ha-1 yr-1 for the different parks to protect the most sensitive ecosystem receptors. For present-day conditions, we find 24 out of 45 parks to be in CL exceedance and 14 more to be marginally so. Many of these are in remote areas of the West. Most (40-85%) of the deposition originates from NOx emissions (fuel combustion). We project future changes in N deposition using representative concentration pathway (RCP) anthropogenic emission scenarios for 2050. These feature 52-73% declines in US NOx emissions relative to present but 19-50% increases in US ammonia (NH3) emissions. Nitrogen deposition at US national parks then becomes dominated by domestic NH3 emissions. While deposition decreases in the East relative to present, there is little progress in the West and increases in some regions. We find that 17-25 US national parks will have CL exceedances in 2050 based on the RCP8.5 and RCP2.6 scenarios. Even in total absence of anthropogenic NOx emissions, 14-18 parks would still have a CL exceedance. Returning all parks to N deposition below CL by 2050 would require at least a 50% decrease in US anthropogenic NH3 emissions relative to RCP-projected 2050 levels.

  17. A regional approach for mineral soil weathering estimation and critical load assessment in boreal Saskatchewan, Canada.

    PubMed

    Whitfield, Colin J; Watmough, Shaun A

    2012-10-15

    In boreal regions of the province of Saskatchewan, Canada, there is concern over emerging acid precursor emission sources associated with the oil sands industry. Base cation weathering rates (BC(w)) and steady-state critical loads of sulfur (CL(S)) were identified for upland forest soil plots (n=107) in 45 ecodistricts according to a new method for approximation of BC(w) in the region. This method was developed by regression of simple soil and site properties with BC(w) calculated through application of a soil chemical model (PROFILE). PROFILE was parameterized using detailed physicochemical data for a subset (n=35) of the sites. Sand content, soil moisture and latitude emerged as important predictive variables in this empirical regression approximation. Base cation weathering varied widely (0.1-8000 mmol(c) m(-3) yr(-1)) across the study sites, consistent with their contrasting soil properties. Several sites had lower rates than observed in other acid-sensitive regions of Canada owing to quartz dominated mineralogy and coarse-textured soils with very low surface area. Weathering was variable within ecodistricts, although rates were consistently low among ecodistricts located in the northwest of the province. Overall, half of the forest plots demonstrated CL(S) less than 45 mmol(c) m(-2) yr(-1). Historically, the acidification risk in this region has been considered low and monitoring has been limited. Given the very low CL(S) in many northern ecodistricts and the potential for increased acid deposition as oil sands activities expand, soil acidification in these regions warrants further study. PMID:22940479

  18. WE-A-17A-05: Differences in Applicator Configuration and Dwell Loading Between Standard and Image-Guided Tandem and Ring (T and R) HDR Brachytherapy

    SciTech Connect

    Damato, A; Cormack, R; Bhagwat, M; Buzurovic, I; Lee, L; Viswanathan, A

    2014-06-15

    Purpose: To investigate differences in: (i) relative location of the tandem and the ring compared to a rigid standard applicator model; and (ii) relative loading and changes in loading pattern between standard and image-guided planning. Methods: All T and R insertions performed in 2013 in our institution under CT- or MR-guidance were analyzed. Standard plans were generated using library applicator models with a fixed relationship between ring and tandem, standardized uniform dwell loading and normalization to point A. The graphic plans and the associated standard-plan dwell configurations were compared: the rings were rigidly registered, and the residual tandem shift, rotation and maximum distance between plan tandem dwell and corresponding model tandem dwell were calculated. The normalization ratio (NR = the ratio of graphic versus standard-plan total reference air kerma [TRAK]), the general loading difference (GLD = the difference between graphic and standard ratios of the tandem versus the ring TRAK), and the percent standard deviation (SD% = SD/mean) of the tandem and the ring TRAK for the graphic plan (all standard-plans SD% = 0) were calculated. Results: 71 T and R were analyzed. Residual tandem shift, rotation and maximum corresponding dwell distance were 1.2±0.8mm (0.4±0.4mm lateral, 0.9±0.8mm craniocaudal, 0.4±0.3mm anterior-posterior), 2.3±1.9deg and 3.4±2.3mm. NR was 0.86±0.11 indicating a lower overall loading of the graphic compared to the standard plans. GLD was -0.12±0.16 indicating a modest increased ring loading relative to the tandem in the graphic plans. SD% was 2.1±1.6% for tandem and 2.8±1.9% for ring, indicating small deviations from uniform loading. Conclusion: Variability in the relative locations of the tandem and the ring necessitates the independent registration of each component model for accurate digitization. Our clinical experience suggests that graphically planned T and R results on average in a lower total dose to the

  19. Experimental study on the thorium-loaded accelerator-driven system at the Kyoto Univ. critical assembly

    SciTech Connect

    Pyeon, C. H.; Yagi, T.; Lim, J. Y.; Misawa, T.

    2012-07-01

    The experimental study on the thorium-loaded accelerator-driven system (ADS) is conducted in the Kyoto Univ. Critical Assembly (KUCA). The experiments are carried out in both the critical and subcritical states for attaining the reaction rates of the thorium capture and fission reactions. In the critical system, the thorium plate irradiation experiment is carried out for the thorium capture and fission reactions. From the results of the measurements, the thorium fission reactions are obtained apparently in the critical system, and the C/E values of reaction rates show the accuracy of relative difference of about 30%. In the ADS experiments with 14 MeV neutrons and 100 MeV protons, the subcritical experiments are carried out in the thorium-loaded cores to obtain the capture reaction rates through the measurements of {sup 115}In(n, {gamma}){sup 116m}In reactions. The results of the experiments reveal the difference between the reaction rate distributions for the change in not only the neutron spectrum but also the external neutron source. The comparison between the measured and calculated reaction rate distributions demonstrates a discrepancy of the accuracy of reaction rate analyses of thorium capture reactions through the thorium-loaded ADS experiments with 14 MeV neutrons. Hereafter, kinetic experiments are planned to be carried out to deduce the delayed neutron decay constants and subcriticality using the pulsed neutron method. (authors)

  20. Determining Exercise Strength Requirements for Astronaut Critical Mission Tasks: Reaching Under G-Load

    NASA Technical Reports Server (NTRS)

    Schaffner, Grant; Bentley, Jason

    2008-01-01

    The critical mission tasks assessments effort seeks to determine the physical performance requirements that astronauts must meet in order to safely and successfully accomplish lunar exploration missions. These assessments will determine astronaut preflight strength, fitness, and flexibility requirements, and the extent to which exercise and other countermeasures must prevent the physical deconditioning associated with prolonged weightlessness. The purpose is to determine the flexibility and strength that crewmembers must possess in order to reach Crew Exploration Vehicle controls during maneuvers that result in sustained acceleration levels ranging from 3.7G to 7.8G. An industry standard multibody dynamics application was used to create human models representing a 5th percentile female, a 50th percentile male, and a 95th percentile male. The additional mass of a space suit sleeve was added to the reaching arm to account for the influence of the suit mass on the reaching effort. The human model was merged with computer models of a pilot seat and control panel for the Crew Exploration Vehicle. Three dimensional paths were created that guided the human models hand from a starting position alongside its thigh to three control targets: a joystick, a keyboard, and an overhead switch panel. The reaching motion to each target was repeated under four vehicle acceleration conditions: nominal ascent (3.7G), two ascent aborts (5.5G and 7.8G) and lunar reentry (4.6G). Elbow and shoulder joint angular excursions were analyzed to assess range of motion requirements. Mean and peak elbow and shoulder joint torques were determined and converted to equivalent resistive exercise loads to assess strength requirements. Angular excursions for the 50th and 95th percentile male models remained within joint range of motion limits. For the 5th percentile female, both the elbow and the shoulder exceeded range of motion limits during the overhead reach. Elbow joint torques ranged from 10 N

  1. Determination of critical loads for cylindrical sandwich panels of composite materials under two-sided compression and shear

    NASA Astrophysics Data System (ADS)

    Rubina, A. L.; Krashakov, Yu. F.

    The problem of determining the critical buckling stress of symmetric and nonsymmetric sandwich panels loaded in two-sided compression and shear is investigated analytically. The governing equation is obtained by solving equations of balance of forces and moments for an element of a sandwich structure in the case of buckling. The solution is based on the general assumptions of the theory of thin shallow shells. The results of the study can be used to optimize the structure of sandwich panels.

  2. The Science and Application of Critical Loads for Deposition of Nitrogen and Sulfur Compounds in National Parks

    NASA Astrophysics Data System (ADS)

    Porter, E.

    2008-12-01

    The National Parks of the U.S. contain resources of unsurpassed beauty and ecological significance. Park managers are directed to preserve the scenery and natural resources in these parks unimpaired for future generations. However, air pollution can damage the very resources that parks were created to preserve and, often, air pollution originates from outside park boundaries and therefore beyond the National Park Service's management jurisdiction. The Clean Air Act provides a framework and certain tools for protecting park resources from air pollution, but despite these programs, air pollution impacts to national park resources are widespread, including acidification or eutrophication from atmospheric deposition of nitrogen and sulfur compounds. Advances in ecosystem research and modeling have allowed national park managers to use critical loads to better evaluate ecosystem condition and set clear management goals for parks. Critical loads define the amount of deposition, usually nitrogen or sulfur compounds, below which harmful effects to a given resource are not expected. Resource protection goals based on critical loads, in turn, can be communicated to federal and State air regulatory agencies, and incorporated into air quality management planning for ecosystem protection. For example, the National Park Service, the Colorado Department of Public Health and Environment, and the Environmental Protection Agency have collaborated to use a critical load to set goals for a nitrogen deposition reduction plan to remedy ecosystem impacts in Rocky Mountain National Park. Elevated nitrogen deposition to the park has caused changes in the type and abundance of aquatic plant species, elevated levels of nitrate in surface waters, elevated levels of nitrogen in spruce needles, long-term accumulation of nitrogen in forest soils, and a shift in alpine tundra plant communities favoring sedges and grasses over the natural wildflower flora. The plan calls for nitrogen deposition to

  3. The effects of display variables and secondary loading on the dual axis critical task performance

    NASA Technical Reports Server (NTRS)

    Swisher, G. M.; Nataraj, S.

    1973-01-01

    The effects of scanning displays for separated instruments, separated versus combined displays, and the effects of secondary loading are investigated. An operator rating scale for handling qualities is established analogous to the Cooper Harper Scale.

  4. Developing Critical Loads of acidity for streams in the Great Smoky Mountains National Park, using PnET-BGC model

    NASA Astrophysics Data System (ADS)

    Fakhraei, H.

    2015-12-01

    Acid deposition has impaired acid-sensitive streams and reduced aquatic biotic integrity in Great Smoky Mountains National Park (GRSM) by decreasing pH and acid neutralizing capacity (ANC). Twelve streams in GRSM are listed by the state of Tennessee as impaired due to low stream pH (pH<6.0) under Section 303(d) of the Clean Water Act. A dynamic biogeochemical model, PnET-BGC, was used to evaluate past, current and potential future changes in soil and water chemistry of watersheds of GRSM in response to changes in acid deposition. Calibrating 30 stream-watersheds in GRSM (including 12 listed impaired streams) to the long-term stream chemistry observations, the model was parameterized for the Park. The calibrated model was used to evaluate the level of atmospheric deposition above which harmful effects occur, known as "critical loads", for individual study watersheds. Estimated critical loads and exceedances (levels of deposition above the critical load) of atmospheric sulfur and nitrogen deposition were depicted through geographic information system maps. Accuracy of model simulations in the presence of uncertainties in the estimated model parameters and inputs was assessed using three uncertainty and sensitivity techniques.

  5. Calculation of theoretical and empirical nutrient N critical loads in the mixed conifer ecosystems of southern California.

    PubMed

    Breiner, Joan; Gimeno, Benjamin S; Fenn, Mark

    2007-01-01

    Edaphic, foliar, and hydrologic forest nutrient status indicators from 15 mixed conifer forest stands in the Sierra Nevada, San Gabriel Mountains, and San Bernardino National Forest were used to estimate empirical or theoretical critical loads (CL) for nitrogen (N) as a nutrient. Soil acidification response to N deposition was also evaluated. Robust empirical relationships were found relating N deposition to plant N uptake (N in foliage), N fertility (litter C/N ratio), and soil acidification. However, no consistent empirical CL were obtained when the thresholds for parameters indicative of N excess from other types of ecosystems were used. Similarly, the highest theoretical CL for nutrient N calculated using the simple mass balance steady state model (estimates ranging from 1.4-8.8 kg N/ha/year) was approximately two times lower than the empirical observations. Further research is needed to derive the thresholds for indicators associated with the impairment of these mixed conifer forests exposed to chronic N deposition within a Mediterranean climate. Further development or parameterization of models for the calculation of theoretical critical loads suitable for these ecosystems will also be an important aspect of future critical loads research. PMID:17450298

  6. Identification of research relating to the critical loads concept and its potential application to the regulation of acidic deposition

    SciTech Connect

    Bhatti, N.

    1993-12-01

    The overwhelming majority of strategies currently implemented to regulate acidic deposition have focused on source-based or emission-control techniques. In the past few years, however, the fact that such source-based. strategies may not be sufficient to prevent adverse ecological effects and may therefore need to be supplemented with other control options, such as receptor-based strategies, has become apparent. Partly in response to this insufficiency of regulatory controls, the US Congress has required the National Acid Precipitation Assessment Program to determine (1) what deposition levels are needed to prevent such ecological damage, (2) whether such safe deposition levels (i.e., critical loads) can realistically be identified, and (3) what the costs and benefits of attaining such deposition levels are. This report reviews and culls the existing research on these alternative control strategies, emphasizing the critical loads concept, to determine the advantages and limitations and the cost-benefit relationships associated with receptor-based control options. The results of this study indicate that in spite of the significant limitations associated with the critical loads concept, this strategy dominates all discussions of non-source-based control options and offers considerable advantages, including cost-effectiveness, over the more traditional source-based control methods. Summaries of 10 of the most relevant studies dealing with alternative control strategies and the costs and benefits associated with them are also presented in this report.

  7. The effect of loading on peri-implant bone: a critical review of the literature.

    PubMed

    Duyck, J; Vandamme, K

    2014-10-01

    In the 90s, there was a general belief that mechanical overloading was one of the main reasons for late implant failure. This triggered research to assess the role of mechanical loading on the establishment and the maintenance of oral implant osseointegration. Animal experimental studies indeed suggested the potential detrimental effect of excessive mechanical load on peri-implant bone, although randomised or controlled clinical trials of treatment interventions of oral implants designed to study overload are lacking. The lack of quantification of so-called overload at the implant level in the intra-oral setting is one of the main shortcomings in the literature. The level of evidence of the studies on bone response to implant loading is weak and does not indicate that overload can lead to peri-implant bone loss, except in case of inflammation. Clinical and animal experimental studies on early and immediate implant loading, however, provide information on the impact of mechanical loading on the process of osseointegration. It is obvious that micromotion between the implant and host tissues compromises osseointegration. However, in case of an efficient force transfer between implant and surrounding tissues, mechanical loading might even stimulate peri-implant bone formation and therefore osseointegration. PMID:24889500

  8. Strategies to optimize lithium-ion supercapacitors achieving high-performance: Cathode configurations, lithium loadings on anode, and types of separator

    NASA Astrophysics Data System (ADS)

    Cao, Wanjun; Li, Yangxing; Fitch, Brian; Shih, Jonathan; Doung, Tien; Zheng, Jim

    2014-12-01

    The Li-ion capacitor (LIC) is composed of a lithium-doped carbon anode and an activated carbon cathode, which is a half Li-ion battery (LIB) and a half electrochemical double-layer capacitor (EDLC). LICs can achieve much more energy density than EDLC without sacrificing the high power performance advantage of capacitors over batteries. LIC pouch cells were assembled using activated carbon (AC) cathode and hard carbon (HC) + stabilized lithium metal power (SLMP®) anode. Different cathode configurations, various SLMP loadings on HC anode, and two types of separators were investigated to achieve the optimal electrochemical performance of the LIC. Firstly, the cathode binders study suggests that the PTFE binder offers improved energy and power performances for LIC in comparison to PVDF. Secondly, the mass ratio of SLMP to HC is at 1:7 to obtain the optimized electrochemical performance for LIC among all the various studied mass ratios between lithium loading amounts and active anode material. Finally, compared to the separator Celgard PP 3501, cellulose based TF40-30 is proven to be a preferred separator for LIC.

  9. Surface water acidification responses and critical loads of sulfur and nitrogen deposition in Loch Vale watershed, Colorado

    USGS Publications Warehouse

    Sullivan, T.J.; Cosby, B.J.; Tonnessen, K.A.; Clow, D.W.

    2005-01-01

    We evaluated the sensitivity of The Loch, a subalpine lake in Rocky Mountain National Park in Colorado, to acidification in response to increased atmospheric loading of sulfur (S) and nitrogen (N) using the Model of Acidification of Groundwater in Catchments (MAGIC). Lake water acid-base chemistry was moderately sensitive to changes in both S and N deposition. However, the loads of S deposition that would drive chronic lake water acid neutralizing capacity (ANC) to below 0 or 20 ??eq L-1 were estimated to be 11 and 8 kg S ha-1 yr-1, respectively, assuming constant future N deposition at current levels. Comparable loads for N deposition, assuming constant future S deposition, were estimated to be 21 and 12 kg N ha-1 yr-1, respectively. Modeling results for Andrews Creek, an alpine tributary to The Loch, suggested critical loads for surface water acidification that averaged about one third lower. Surface water ANC = 50 ??eq L-1 was projected to occur in 50 years in The Loch if S or N deposition increased by a moderate amount (<40%) but could not be achieved in Andrews Creek by reducing either S or N deposition to zero. On the basis of the results of synoptic surveys of lake water chemistry, about one fifth of the wilderness lakes in the Colorado Front Range are more acid-sensitive than The Loch. This modeling exercise suggests the need for a regional analysis of critical loads for the larger population of acid-sensitive aquatic resources in order to provide part of the scientific foundation for federally mandated land management decisions. Copyright 2005 by the American Geophysical Union.

  10. Streamwater acid-base chemistry and critical loads of atmospheric sulfur deposition in Shenandoah National Park, Virginia.

    PubMed

    Sullivan, T J; Cosby, B J; Webb, J R; Dennis, R L; Bulger, A J; Deviney, F A

    2008-02-01

    A modeling study was conducted to evaluate the acid-base chemistry of streams within Shenandoah National Park, Virginia and to project future responses to sulfur (S) and nitrogen (N) atmospheric emissions controls. Many of the major stream systems in the park have acid neutralizing capacity (ANC) less than 20 microeq/L, levels at which chronic and/or episodic adverse impacts on native brook trout are possible. Model hindcasts suggested that none of these streams had ANC less than 50 microeq/L in 1900. Model projections, based on atmospheric emissions controls representative of laws already enacted as of 2003, suggested that the ANC of those streams simulated to have experienced the largest historical decreases in ANC will increase in the future. The levels of S deposition that were simulated to cause streamwater ANC to increase or decrease to three specified critical levels (0, 20, and 50 microeq/L) ranged from less than zero (ANC level not attainable) to several hundred kg/ha/year, depending on the selected site and its inherent acid-sensitivity, selected ANC endpoint criterion, and evaluation year for which the critical load was calculated. Several of the modeled streams situated on siliciclastic geology exhibited critical loads <0 kg/ha/year to achieve ANC >50 microeq/L in the year 2040, probably due at least in part to base cation losses from watershed soil. The median modeled siliciclastic stream had a calculated critical load to achieve ANC >50 microeq/L in 2100 that was about 3 kg/ha/year, or 77% lower than deposition in 1990, representing the time of model calibration. PMID:17492359

  11. Soil acidification in southern Switzerland between 1987 and 1997: A case study based on the critical load concept

    SciTech Connect

    Blaser, P.; Zimmermann, S.; Luster, J. ); Zysset, M. . Dept. of Soil Sciences)

    1999-07-15

    Southern Switzerland with its mainly acidic bedrock is potentially very sensitive to the effects of atmospheric proton input. In addition, this region suffers from relatively high acid deposition originating from the greater Milano area. The soil solution composition at different depths of a cryptopodzolic soil was monitored over a 10 year period with samples collected fortnightly. On the basis of the concept of critical loads of acidity, the molar ratio of base nutrient cations (BC) to aluminum was used as the parameter to assess acidification. Despite characteristic seasonal short-term variations of BC and Al, which could be attributed qualitatively to specific soil chemical processes, statistically significant trends over the entire observation period were observed. In all horizons a depletion of BC concentrations indicated an impoverishment of the nutrient status of the vegetation. Aluminum decreased in the upper soil, whereas a significant increase was observed at the lowest soil depth. The BC/Al ratio decreased significantly in all mineral soil horizons, indicating rapid soil acidification. Considering the constant decrease of acid deposition at the site during the observation period with values significantly below calculated critical loads, the observed acidification is attribute to a memory effect of the high acid loads between 1965 and 1985.

  12. Loading and testing a light scattering cell with a binary fluid mixture near its critical composition

    NASA Astrophysics Data System (ADS)

    Jacobs, Donald T.; Becker, James S.

    1993-06-01

    Critical phenomena has been the subject of physics research for many years. However, only in recent years has the research effort become intense. The current intensity has caused the study of critical phenomena to be grouped into a previous older era and a present contemporary era. Turbidity cell filling with methanol cyclohexane is one of the first steps toward a further understanding of critical phenomena. Work performed during the research period is outlined. During this period, research was spent developing apparatus and techniques that will make it possible to study critical phenomena through turbidity measurements on methanol cyclohexane. Topics covered range from the orientation of turbidity cell parts for assembly to the filling apparatus and procedure used when th cell is built. The last section will briefly cover some of the observations made when viewing the cell in a controlled water bath. However, before mention is made of the specifics of the summer research, a short introduction to critical phenomena and turbidity and how they relate to this experiment is provided.

  13. Loading and testing a light scattering cell with a binary fluid mixture near its critical composition

    NASA Technical Reports Server (NTRS)

    Jacobs, Donald T.; Becker, James S.

    1993-01-01

    Critical phenomena has been the subject of physics research for many years. However, only in recent years has the research effort become intense. The current intensity has caused the study of critical phenomena to be grouped into a previous older era and a present contemporary era. Turbidity cell filling with methanol cyclohexane is one of the first steps toward a further understanding of critical phenomena. Work performed during the research period is outlined. During this period, research was spent developing apparatus and techniques that will make it possible to study critical phenomena through turbidity measurements on methanol cyclohexane. Topics covered range from the orientation of turbidity cell parts for assembly to the filling apparatus and procedure used when th cell is built. The last section will briefly cover some of the observations made when viewing the cell in a controlled water bath. However, before mention is made of the specifics of the summer research, a short introduction to critical phenomena and turbidity and how they relate to this experiment is provided.

  14. Comparison among model estimates of critical loads of acidic deposition using different sources and scales of input data.

    PubMed

    McDonnell, T C; Cosby, B J; Sullivan, T J; McNulty, S G; Cohen, E C

    2010-09-01

    The critical load (CL) of acidic atmospheric deposition represents the load of acidity deposited from the atmosphere to the earth's surface at which harmful acidification effects on sensitive biological receptors are thought to occur. In this study, the CL for forest soils was estimated for 27 watersheds throughout the United States using a steady-state mass balance approach based on both national and site-specific data and using different approaches for estimating base cation weathering. Results suggested that the scale and source of input data can have large effects on the calculated CL and that the most important parameter in the steady-state model used to estimate CL is base cation weathering. These results suggest that the data and approach used to estimate weathering must be robust if the calculated CL is to be useful for its intended purpose. PMID:20609503

  15. Extraction Method Plays Critical Role in Antibacterial Activity of Propolis-Loaded Hydrogels.

    PubMed

    de Lima, Gabriel G; de Souza, Ronaldo O; Bozzi, Aline D; Poplawska, Malgorzata A; Devine, Declan M; Nugent, Michael J D

    2016-03-01

    Extracted propolis has been used for a long time as a remedy. However, if the release rate of propolis is not controlled, the efficacy is reduced. To overcome this issue, extracted propolis was added to a cryogel system. Propolis collected from southern Brazil was extracted using different methods and loaded at different concentrations into polyvinyl alcohol (PVA) and polyacrylic acid hydrogels as carrier systems. The material properties were investigated with a focus on the propolis release profiles and the cryogel antibacterial properties against 4 different bacteria, namely: Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Pseudomonas putida. Swelling studies indicated that the swelling of the hydrogel was inversely related to propolis content. In addition, propolis release studies indicated a decreased release rate with increased propolis loading. PVA and PVA/polyacrylic acid-loaded propolis were effective against all 4 bacteria studied. These results indicate that the efficacy of propolis can be enhanced by incorporation into hydrogel carrier systems and that hydrogels with higher concentrations of propolis can be considered for use as bactericide dressing. PMID:26886307

  16. Critical Configuration and Physics Mesaurements for Graphite Reflected Assemblies of U(93.15)O2 Fuel Rods (1.27-CM Pitch)

    SciTech Connect

    Margaret A. Marshall

    2011-09-01

    A series of critical experiments were completed in 1962-1965 at Oak Ridge National Laboratory's Critical Experiments Facility in support of the Medium-Power Reactor Experiments (MPRE) program. In the late 1950's efforts were made to study 'power plants for the production of electrical power in space vehicles'. The MPRE program was a part of those efforts and studied the feasibility of a stainless steel system, boiling potassium 1 MW(t), or about 140 kW(e), reactor. The program was carried out in FY 1964, 1965, and 1966. A summary of the program's effort was compiled in 1967. The delayed critical experiments served as a mockup of a small, potassium-cooled space power reactor for validation of reactor calculations and reactor physics methods. Initial experiments, performed in November and December of 1962, consisted of a core of unmoderated 253 stainless steel tubes, each containing 26 UO2 fuel pellets, surrounded by a graphite reflector. Measurements were made to determine critical reflector arrangements, fission-rate distributions, and cadmium ratio distributions. Subsequent experiments used beryllium reflectors and also measured the reactivity for various materials placed in the core. 'The [assemblies were built] on [a] vertical assembly machine so that the movable part was the core and bottom reflector.' The experiment studied within this evaluation was the first of the series and had the 253 fuel tubes packed tightly into a 22.87 cm outside diameter (OD) core tank. Two critical configurations were found by varying the amount of graphite reflector (References 1 and 2). Information for this evaluation was compiled from Reference 1 and 2, reports on subsequent experiments in the series, and the experimental logbook as well as from communication with the experimenter, John T. Mihalczo.

  17. A properly configured ring structure is critical for the function of the mitochondrial DNA recombination protein, Mgm101.

    PubMed

    Nardozzi, Jonathan D; Wang, Xiaowen; Mbantenkhu, MacMillan; Wilkens, Stephan; Chen, Xin Jie

    2012-10-26

    Mgm101 is a Rad52-type recombination protein of bacteriophage origin required for the repair and maintenance of mitochondrial DNA (mtDNA). It forms large oligomeric rings of ∼14-fold symmetry that catalyze the annealing of single-stranded DNAs in vitro. In this study, we investigated the structural elements that contribute to this distinctive higher order structural organization and examined its functional implications. A pair of vicinal cysteines, Cys-216 and Cys-217, was found to be essential for mtDNA maintenance. Mutations to the polar serine, the negatively charged aspartic and glutamic acids, and the hydrophobic amino acid alanine all destabilize mtDNA in vivo. The alanine mutants have an increased propensity of forming macroscopic filaments. In contrast, mutations to aspartic acid drastically destabilize the protein and result in unstructured aggregates with severely reduced DNA binding activity. Interestingly, the serine mutants partially disassemble the Mgm101 rings into smaller oligomers. In the case of the C216S mutant, a moderate increase in DNA binding activity was observed. By using small angle x-ray scattering analysis, we found that Mgm101 forms rings of ∼200 Å diameter in solution, consistent with the structure previously established by transmission electron microscopy. We also found that the C216A/C217A double mutant tends to form broken rings, which likely provide free ends for seeding the growth of the super-stable but functionally defective filaments. Taken together, our data underscore the importance of a delicately maintained ring structure critical for Mgm101 activity. We discuss a potential role of Cys-216 and Cys-217 in regulating Mgm101 function and the repair of damaged mtDNA under stress conditions. PMID:22948312

  18. The lithospheric-scale 3D structural configuration of the North Alpine Foreland Basin constrained by gravity modelling and the calculation of the 3D load distribution

    NASA Astrophysics Data System (ADS)

    Przybycin, Anna M.; Scheck-Wenderoth, Magdalena; Schneider, Michael

    2014-05-01

    The North Alpine Foreland Basin is situated in the northern front of the European Alps and extends over parts of France, Switzerland, Germany and Austria. It formed as a wedge shaped depression since the Tertiary in consequence of the Euro - Adriatic continental collision and the Alpine orogeny. The basin is filled with clastic sediments, the Molasse, originating from erosional processes of the Alps and underlain by Mesozoic sedimentary successions and a Paleozoic crystalline crust. For our study we have focused on the German part of the basin. To investigate the deep structure, the isostatic state and the load distribution of this region we have constructed a 3D structural model of the basin and the Alpine area using available depth and thickness maps, regional scale 3D structural models as well as seismic and well data for the sedimentary part. The crust (from the top Paleozoic down to the Moho (Grad et al. 2008)) has been considered as two-parted with a lighter upper crust and a denser lower crust; the partition has been calculated following the approach of isostatic equilibrium of Pratt (1855). By implementing a seismic Lithosphere-Asthenosphere-Boundary (LAB) (Tesauro 2009) the crustal scale model has been extended to the lithospheric-scale. The layer geometry and the assigned bulk densities of this starting model have been constrained by means of 3D gravity modelling (BGI, 2012). Afterwards the 3D load distribution has been calculated using a 3D finite element method. Our results show that the North Alpine Foreland Basin is not isostatically balanced and that the configuration of the crystalline crust strongly controls the gravity field in this area. Furthermore, our results show that the basin area is influenced by varying lateral load differences down to a depth of more than 150 km what allows a first order statement of the required compensating horizontal stress needed to prevent gravitational collapse of the system. BGI (2012). The International

  19. Experimental study of acoustic loads on an upper-surface-blown STOL airplane configuration. [Langley full-scale wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Willis, C. M.; Schoenster, J. A.

    1979-01-01

    Fluctuating pressure levels were measured on the flap and fuselage of an upper-surface-blown jet-flap airplane configuration in a wind tunnel. The model tested had turbofan engines with a bypass ratio of 3 and a thrust rating of 10 kN. Rectangular nozzles were mounted flush with the upper surface at 35 percent of the wing chord. Test parameters were flap deflection angle, jet impingement angle, angle of attack, free-stream velocity, spanwise location of the engine, and jet dynamic pressure. Load levels were high throughout the jet impingement region, with the highest levels (about 159 dB) occurring on the fuselage and near the knee of the flap. The magnitude of the forward-velocity effect appeared to depend upon the ratio of free-stream and jet velocities. Good agreement was obtained between fluctuating pressure spectra measured at jet dynamic pressures of 7 and 22 kPa when the spectra were scaled by nondimensional functions of dynamic pressure, velocity, and the empirical relationship between dynamic pressure and overall fluctuating pressure level.

  20. Self-Reevaluation as a Critical Component in Sustained Viral Load Change for HIV+ Adults with Alcohol Problems

    PubMed Central

    Longmire-Avital, Buffie; Golub, Sarit A.

    2010-01-01

    Self-reevaluation is one of the ten processes of change in the transtheoretical model and involves cognitive reappraisal of how behavior change is part of one’s identity. Although self-reevaluation is a critical motivator for individuals in the contemplation stage of change, few studies have examined its impact on disease progression associated with sustained behavior change. This study investigated the contribution of self-reevaluation on sustained viral load improvement among 143 participants in a randomized controlled trial testing an eight-session intervention (Project Positive Living through Understanding and Support) designed to improve treatment adherence among HIV+ adults with alcohol problems. Participants’ self-reevaluation scores at 3 months emerged as significant and independent predictors of sustained improvement in viral load at 6 months, over and above self-reported HAART dose adherence (p<0.05). Results underscore the role of self-reevaluation as a critical factor in behavioral interventions and highlight its role in sustained change necessary to slow disease progression. PMID:20668976

  1. COMPARISON OF SELECTED CRITICAL LOADS ESTIMATION APPROACHES FOR ASSESSING THE EFFECTS OF SULFATE DEPOSITION ON LAKES IN THE NORTHEASTERN UNITED STATES

    EPA Science Inventory

    Recent international agreements for controlling atmospheric pollutant emissions have been based on the use of target loads that, in turn, require countries to develop national estimates of critical loads--the highest deposition of acidifying compounds that will not cause chemical...

  2. CRITICAL CONFIGURATION FOR BERYLLIUM REFLECTED ASSEMBLIES OF U(93.15)O2 FUEL RODS (1.506-CM PITCH AND 7-TUBE CLUSTERS)

    SciTech Connect

    Margaret A. Marshall

    2012-05-01

    A series of critical experiments were completed in 1962-1965 at Oak Ridge National Laboratory’s Critical Experiments Facility in support of the Medium-Power Reactor Experiments (MPRE) program. In the late 1950’s efforts were made to study “power plants for the production of electrical power in space vehicles”. The MPRE program was a part of those efforts and studied the feasibility of a stainless steel system, boiling potassium 1 MW(t), or about 140 kW(e), reactor. The program was carried out in [fiscal years] 1964, 1965, and 1966. A summary of the program’s effort was compiled in 1967. The delayed critical experiments were a mockup of a small, potassium-cooled space power reactor for validation of reactor calculations and reactor physics methods. Initial experiments, performed in November and December of 1962, consisted of a core of 253 unmoderated stainless steel tubes, each containing 26 UO2 fuel pellets, surrounded by a graphite reflector. Measurements were made to determine critical reflector arrangements, fission-rate distributions, and cadmium ratio distributions. “The [assemblies were built] on [a] vertical assembly machine so that the movable part was the core and bottom reflector.” The first two experiments in the series were evaluated in HEU-COMP-FAST-001 (SCCA-FUND-EXP-001) and HEU-COMP-FAST-002 (SCCA-FUND-EXP-002). The first experiment had the 253 fuel tubes packed tightly into a 22.87 cm outside diameter (OD) core tank (References 1 and 2). The second experiment in the series, performed in early 1963, had the 253 fuel tubes at a 1.506-cm triangular lattice in a 25.96 cm OD core tank and graphite reflectors on all sides. The third set of experiments in the series, performed in mid-1963, which is studied in this evaluation, used beryllium reflectors. The beryllium reflected system was the preferred reactor configuration for this application because of the small thickness of the reflector. The two core configurations had the 253 fuel tubes

  3. Design oriented identification of critical times in transient response. [due to dynamic loads

    NASA Technical Reports Server (NTRS)

    Haftka, R. T.; Watson, L. T.; Grandhi, R. V.

    1984-01-01

    Two techniques are presented for reducing the computational effort in identifying the critical time points. One approach is an adaptive search technique, well suited for the case where the response is exactly known. The other technique, useful for noisy response, is based on a least-squares spline approximation of the response. The possibility of grouping several closely spaced local peaks to identify a single super peak from each group is also investigated. The computational efficiency of the techniques proposed here is illustrated by two examples.

  4. The mechanisms of plastic strain accommodation and post critical behavior of heterogeneous reactive composites subject to dynamic loading

    NASA Astrophysics Data System (ADS)

    Olney, Karl L.

    The dynamic behavior of granular/porous and laminate reactive materials is of interest due to their practical applications; reactive structural components, reactive fragments, etc. The mesostructural properties control meso- and macro-scale dynamic behavior of these heterogeneous composites including the behavior during the post-critical stage of deformation. They heavily influence mechanisms of fragment generation and the in situ development of local hot spots, which act as sites of ignition in these materials. This dissertation concentrates on understanding the mechanisms of plastic strain accommodation in two representative reactive material systems with different heterogeneous mesostructrues: Aluminum-Tungsten granular/porous and Nickel-Aluminum laminate composites. The main focus is on the interpretation of results of the following dynamic experiments conducted at different strain and strain rates: drop weight tests, explosively expanded ring experiments, and explosively collapsed thick walled cylinder experiments. Due to the natural limitations in the evaluation of the mesoscale behavior of these materials experimentally and the large variation in the size scales between the mesostructural level and the sample, it is extremely difficult, if not impossible, to examine the mesoscale behavior in situ. Therefore, numerical simulations of the corresponding experiments are used as the main tool to explore material behavior at the mesoscale. Numerical models were developed to elucidate the mechanisms of plastic strain accommodation and post critical behavior in these heterogeneous composites subjected to dynamic loading. These simulations were able to reproduce the qualitative and quantitative features that were observable in the experiments and provided insight into the evolution of the mechanisms of plastic strain accommodation and post critical behavior in these materials with complex mesotructure. Additionally, these simulations provided a framework to examine

  5. A perfusion bioreactor system efficiently generates cell-loaded bone substitute materials for addressing critical size bone defects.

    PubMed

    Kleinhans, Claudia; Mohan, Ramkumar Ramani; Vacun, Gabriele; Schwarz, Thomas; Haller, Barbara; Sun, Yang; Kahlig, Alexander; Kluger, Petra; Finne-Wistrand, Anna; Walles, Heike; Hansmann, Jan

    2015-09-01

    Critical size bone defects and non-union fractions are still challenging to treat. Cell-loaded bone substitutes have shown improved bone ingrowth and bone formation. However, a lack of methods for homogenously colonizing scaffolds limits the maximum volume of bone grafts. Additionally, therapy robustness is impaired by heterogeneous cell populations after graft generation. Our aim was to establish a technology for generating grafts with a size of 10.5 mm in diameter and 25 mm of height, and thus for grafts suited for treatment of critical size bone defects. Therefore, a novel tailor-made bioreactor system was developed, allowing standardized flow conditions in a porous poly(L-lactide-co-caprolactone) material. Scaffolds were seeded with primary human mesenchymal stem cells derived from four different donors. In contrast to static experimental conditions, homogenous cell distributions were accomplished under dynamic culture. Additionally, culture in the bioreactor system allowed the induction of osteogenic lineage commitment after one week of culture without addition of soluble factors. This was demonstrated by quantitative analysis of calcification and gene expression markers related to osteogenic lineage. In conclusion, the novel bioreactor technology allows efficient and standardized conditions for generating bone substitutes that are suitable for the treatment of critical size defects in humans. PMID:26011163

  6. A perfusion bioreactor system efficiently generates cell‐loaded bone substitute materials for addressing critical size bone defects

    PubMed Central

    Kleinhans, Claudia; Mohan, Ramkumar Ramani; Vacun, Gabriele; Schwarz, Thomas; Haller, Barbara; Sun, Yang; Kahlig, Alexander; Kluger, Petra; Finne‐Wistrand, Anna; Walles, Heike

    2015-01-01

    Abstract Critical size bone defects and non‐union fractions are still challenging to treat. Cell‐loaded bone substitutes have shown improved bone ingrowth and bone formation. However, a lack of methods for homogenously colonizing scaffolds limits the maximum volume of bone grafts. Additionally, therapy robustness is impaired by heterogeneous cell populations after graft generation. Our aim was to establish a technology for generating grafts with a size of 10.5 mm in diameter and 25 mm of height, and thus for grafts suited for treatment of critical size bone defects. Therefore, a novel tailor‐made bioreactor system was developed, allowing standardized flow conditions in a porous poly(L‐lactide‐co‐caprolactone) material. Scaffolds were seeded with primary human mesenchymal stem cells derived from four different donors. In contrast to static experimental conditions, homogenous cell distributions were accomplished under dynamic culture. Additionally, culture in the bioreactor system allowed the induction of osteogenic lineage commitment after one week of culture without addition of soluble factors. This was demonstrated by quantitative analysis of calcification and gene expression markers related to osteogenic lineage. In conclusion, the novel bioreactor technology allows efficient and standardized conditions for generating bone substitutes that are suitable for the treatment of critical size defects in humans. PMID:26011163

  7. Colistin Population Pharmacokinetics after Application of a Loading Dose of 9 MU Colistin Methanesulfonate in Critically Ill Patients

    PubMed Central

    Friberg, Lena E.; Pontikis, Konstantinos; Ioannidis, Konstantinos; Tsagkari, Vasiliki; Galani, Lamprini; Kostakou, Eirini; Baziaka, Fotini; Paskalis, Charalambos; Koutsoukou, Antonia; Giamarellou, Helen

    2015-01-01

    Colistin has been revived, in the era of extensively drug-resistant (XDR) Gram-negative infections, as the last-resort treatment in critically ill patients. Recent studies focusing on the optimal dosing strategy of colistin have demonstrated the necessity of a loading dose at treatment initiation (D. Plachouras, M. Karvanen, L. E. Friberg, E. Papadomichelakis, A. Antoniadou, I. Tsangaris, I. Karaiskos, G. Poulakou, F. Kontopidou, A. Armaganidis, O. Cars, and H. Giamarellou, Antimicrob Agents Chemother 53:3430–3436, 2009, http://dx.doi.org/10.1128/AAC.01361-08; A. F. Mohamed, I. Karaiskos, D. Plachouras, M. Karvanen, K. Pontikis, B. Jansson, E. Papadomichelakis, A. Antoniadou, H. Giamarellou, A. Armaganidis, O. Cars, and L. E. Friberg, Antimicrob Agents Chemother 56:4241– 4249, 2012, http://dx.doi.org/10.1128/AAC.06426-11; S. M. Garonzik, J. Li, V. Thamlikitkul, D. L. Paterson, S. Shoham, J. Jacob, F. P. Silveira, A. Forrest, and R. L. Nation, Antimicrob Agents Chemother 55:3284–3294, 2011, http://dx.doi.org/10.1128/AAC.01733-10). In 19 critically ill patients with suspected or microbiologically documented infections caused by XDR Gram-negative strains, a loading dose of 9 MU colistin methanesulfonate (CMS) (∼270 mg colistin base activity) was administered with a maintenance dose of 4.5 MU every 12 h, commenced after 24 h. Patients on renal replacement were excluded. CMS infusion was given over 30 min or 1 h. Repeated blood sampling was performed after the loading dose and after the 5th or 6th dose. Colistin concentrations and measured CMS, determined after hydrolization to colistin and including the partially sulfomethylated derivatives, were determined with a liquid chromatography-tandem mass spectrometry assay. Population pharmacokinetic analysis was conducted in NONMEM with the new data combined with data from previous studies. Measured colistimethate concentrations were described by 4 compartments for distribution and removal of sulfomethyl groups

  8. Colistin Population Pharmacokinetics after Application of a Loading Dose of 9 MU Colistin Methanesulfonate in Critically Ill Patients.

    PubMed

    Karaiskos, Ilias; Friberg, Lena E; Pontikis, Konstantinos; Ioannidis, Konstantinos; Tsagkari, Vasiliki; Galani, Lamprini; Kostakou, Eirini; Baziaka, Fotini; Paskalis, Charalambos; Koutsoukou, Antonia; Giamarellou, Helen

    2015-12-01

    Colistin has been revived, in the era of extensively drug-resistant (XDR) Gram-negative infections, as the last-resort treatment in critically ill patients. Recent studies focusing on the optimal dosing strategy of colistin have demonstrated the necessity of a loading dose at treatment initiation (D. Plachouras, M. Karvanen, L. E. Friberg, E. Papadomichelakis, A. Antoniadou, I. Tsangaris, I. Karaiskos, G. Poulakou, F. Kontopidou, A. Armaganidis, O. Cars, and H. Giamarellou, Antimicrob Agents Chemother 53:3430-3436, 2009, http://dx.doi.org/10.1128/AAC.01361-08; A. F. Mohamed, I. Karaiskos, D. Plachouras, M. Karvanen, K. Pontikis, B. Jansson, E. Papadomichelakis, A. Antoniadou, H. Giamarellou, A. Armaganidis, O. Cars, and L. E. Friberg, Antimicrob Agents Chemother 56:4241- 4249, 2012, http://dx.doi.org/10.1128/AAC.06426-11; S. M. Garonzik, J. Li, V. Thamlikitkul, D. L. Paterson, S. Shoham, J. Jacob, F. P. Silveira, A. Forrest, and R. L. Nation, Antimicrob Agents Chemother 55:3284-3294, 2011, http://dx.doi.org/10.1128/AAC.01733-10). In 19 critically ill patients with suspected or microbiologically documented infections caused by XDR Gram-negative strains, a loading dose of 9 MU colistin methanesulfonate (CMS) (∼ 270 mg colistin base activity) was administered with a maintenance dose of 4.5 MU every 12 h, commenced after 24 h. Patients on renal replacement were excluded. CMS infusion was given over 30 min or 1 h. Repeated blood sampling was performed after the loading dose and after the 5th or 6th dose. Colistin concentrations and measured CMS, determined after hydrolization to colistin and including the partially sulfomethylated derivatives, were determined with a liquid chromatography-tandem mass spectrometry assay. Population pharmacokinetic analysis was conducted in NONMEM with the new data combined with data from previous studies. Measured colistimethate concentrations were described by 4 compartments for distribution and removal of sulfomethyl groups, while

  9. A Survey on Investigating the Need for Intelligent Power-Aware Load Balanced Routing Protocols for Handling Critical Links in MANETs

    PubMed Central

    Sivakumar, B.; Bhalaji, N.; Sivakumar, D.

    2014-01-01

    In mobile ad hoc networks connectivity is always an issue of concern. Due to dynamism in the behavior of mobile nodes, efficiency shall be achieved only with the assumption of good network infrastructure. Presence of critical links results in deterioration which should be detected in advance to retain the prevailing communication setup. This paper discusses a short survey on the specialized algorithms and protocols related to energy efficient load balancing for critical link detection in the recent literature. This paper also suggests a machine learning based hybrid power-aware approach for handling critical nodes via load balancing. PMID:24790546

  10. Spatial Variation of Atmospheric Nitrogen Deposition and Estimated Critical Loads for Aquatic Ecosystems in the Greater Yellowstone Area

    NASA Astrophysics Data System (ADS)

    Nanus, L.; McMurray, J. A.; Clow, D. W.; Saros, J. E.; Blett, T.

    2015-12-01

    Aquatic ecosystems at high-elevations in the Greater Yellowstone Area (GYA) are sensitive to the effects of atmospheric nitrogen (N) deposition. Current and historic N deposition has impacted aquatic ecosystems in the GYA and N deposition is increasing in many areas. Anticipated changes in atmospheric emissions may further affect these sensitive ecosystems. Understanding the spatial variation in atmospheric N deposition is needed to develop estimates of air pollution critical loads for aquatic ecosystems in complex terrain. For the GYA, high resolution (400 meter) maps were developed for 1993-2014 to identify areas of high loading of mean annual Total N deposition (wet + dry) and wet deposition of inorganic N (nitrate and ammonium). Total N deposition estimates in the GYA range from ≤ 1.4 to 7.5 kg N ha-1 yr-1 and show greater variability than inorganic N deposition. Spatially explicit estimates of critical loads of N deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed using a geostatistical approach. CLNdep in the GYA ranges from less than 1.5 kg N ha-1 yr-1 to over 10 kg N ha-1 yr-1 and variability is controlled by differences in basin characteristics. The lowest CLNdep estimates occurred in high-elevation basins with steep slopes, sparse vegetation, and exposed bedrock, including areas within GYA Wilderness boundaries. These areas often have high inorganic N deposition (>3 kg N ha-1 yr-1), resulting in CLNdep exceedances greater than 1.5 kg N ha-1 yr-1. The N deposition maps were used to identify CLNdep exceedances for aquatic ecosystems, and to explore scale dependence and boundary issues related to estimating CLNdep. Based on a NO3- threshold of 1.0 μmol L-1, inorganic N deposition exceeds CLNdep in 12% of the GYA, and Total N deposition is in exceedance for 23% of the GYA. These maps can be used to help identify and protect sensitive ecosystems that may be impacted by excess N deposition in the GYA.

  11. The Influence of Salmonid Spawning on Grain Architecture, Critical Bed Shear Stress, and Bed Load Transport in Streams

    NASA Astrophysics Data System (ADS)

    Buxton, T.; Buffington, J. M.; Yager, E. M.; Fremier, A. K.; Hassan, M. A.

    2012-12-01

    Salmonid spawning occurs in many high to mid-order streams in North America and Europe, but the detailed mechanics of this disturbance on stream bed mobility is not well studied. We calculated and measured spawning effects on incipient bed mobility and sediment transport in a laboratory flume and found that the tailspill portion of simulated spawning nests ("redds") are less stable than unspawned beds. This result agrees with field research by others, but counters prior calculations of tailspill stability that used grain architecture relationships derived from unspawned beds. Redds have coarser and better sorted surfaces, which reduce grain exposure and protrusion compared to unspawned beds, but load cell measurements of the total resistance to movement of grains on redds were lower despite deeper grain pockets and larger pivot angles. This is because the redd-building process flushed fine sediment that had previously cemented bed material, resulting in a looser bed structure and more mobile grains. These observations are supported by force balance calculations of critical shear stress on redds being lower on average than on unspawned beds. Computational results are supported by visual observations and measurements of bed load transport from redds and unspawned beds in the flume, where redds mobilized sooner and exhibited a higher sediment transport rate than unspawned beds. Redds were observed to erode by translating, then dispersing and evacuating downstream, before grains on the unspawned bed mobilized. Further increase in discharge mobilized greater proportions of the unspawned bed but did not scour the deeper portion of redds where spawners deposit their eggs. Our results suggest both an evolutionary trade-off and advantage to large spawning populations. Namely, the structurally loose tailspill likely increases intragravel flow to eggs at the expense of tailspill instability, which may sufficiently elevate sediment yields in streams with high spawner densities

  12. Fracture behavior under fatigue loading at room temperature and its influence on critical current of Nb-Ti/Cu composite wire

    NASA Astrophysics Data System (ADS)

    Hojo, Masaki; Iwasaki, Naoya; Sekino, Fumiaki; Ochiai, Shojiro; Sakai, Shuji; Watanabe, Kazuo

    1999-11-01

    Fracture behavior under fatigue loading at room temperature and its influence on critical superconducting current at 4.2 K were investigated for Nb-Ti/Cu multifilamentary composite wire with a copper ratio of 7.83 and an overall diameter of 0.504 mm in which 24 Nb-Ti filaments were embedded. There was a knee in the relation between the applied maximum stress and the number of cycles to failure ( S- N relations). The fracture mechanism below and above this knee was different. When the maximum stress in the fatigue test was high, extensive multiple necking of the Nb-Ti filament occurred, and this was responsible for the final fracture of the composite wire. On the other hand, when the maximum stress in the fatigue tests was low, the fatigue crack nucleated in the copper, which grew and caused the fracture of the Nb-Ti filaments. The critical current was insensitive to fatigue loading when the maximum stress was low. When the maximum stress was high, the critical current after fatigue loading was lower than that after static loading. This was due to severe multiple necking during fatigue loading. Extracted Nb-Ti filaments were also fatigued using a specially designed fatigue testing machine. The S- N curve of filaments agreed well with the stress component of the filament calculated from the S- N relation of the composite wire.

  13. Buckling of Beams and Columns under Combined Axial and Horizontal Loading with Various Axial Loading Application Locations

    NASA Astrophysics Data System (ADS)

    Javidinejad, Amir

    2012-12-01

    In this paper the buckling behaviour of an I-beam under combined axial and horizontal side loading is examined. It is to shown that the actual application location of the axial loading governs the buck- ling behaviour of the long I-beam. Theoretical formulation is developed to determine the critical buckling load for such combined loading configura- tion from the elastic static theory. Both, the beam deflection theoretical model and the critical load capacity are derived for this combined loading condition. The Finite Element Analysis (FEA) is utilized to apply the axial load on the beam at various configuration locations and it is shown that this application location determines the buckling behaviour and the critical load of the buckling of the I-beam. Numerical example is given.

  14. Load and dynamic assessment of B-52B-008 carrier aircraft for finned configuration 1 space shuttle solid rocket booster deceleration subsystem drop test vehicle. Volume 4: Pylon load data

    NASA Technical Reports Server (NTRS)

    Quade, D. A.

    1978-01-01

    The pylon loading at the drop test vehicle and wing interface attack points is presented. The loads shown are determined using a stiffness method, which assumes the side stiffness of the forward hook guide and the fore and aft stiffness of each drag pin to be equal. The net effect of this assumption is that the forward hook guide reacts approximately 96% of the drop test vehicle yawing moment. For a comparison of these loads to previous X-15 analysis design loadings, see Volume 1 of this document.

  15. Load and dynamic assessment of B-52B-008 carrier aircraft for finned configuration 1 space shuttle solid rocket booster decelerator subsystem drop test vehicle. Volume 3: Pylon load data method 1

    NASA Technical Reports Server (NTRS)

    Quade, D. A.

    1978-01-01

    The pylon loading at the drop test vehicle and wing interface attach points is presented. The loads shown are determined using a stiffness method, which assumes the side stiffness of the foreward hook guide to be one-fourth of the fore and aft stiffness of each drag pin. The net effect of this assumption is that the forward hook guide reacts approximately 85% of the drop test vehicle yawing moment. For a comparison of these loads to previous X-15 analysis design loadings, see Volume 1 of this document.

  16. Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India.

    NASA Astrophysics Data System (ADS)

    Sharma, Disha; Kulshrestha, Umesh

    Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India. The Critical Load approach alongwith integrated assessment models has been used in the European nations for policy formations to reduce acidic emissions. This unique approach was applied to assess the of vulnerability of natural systems to the present day atmospheric pollution scenario. The calculated values of critical loads of sulphur ( 225 - 275 eq/ha/yr) and nitrogen (298 - 303 eq/ha/yr), for the soil system in Delhi, were calculated with respect to Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S) = 26.40 eq/ha/yr) and nitrogen (PL(N) = 36.51 eq/ha/yr) were found to be much lower than their critical loads without posing any danger of atmospheric acidic deposition on the soil systems. The study indicated that the system is still protective due to high pH of soil. The nature of buffering capability of calcium derived from soil dust can be considered as a natural tool to combat acidification in the Indian region. The results showed that the pollution status in Delhi is still within the safe limits. However, at the pace at which the city is growing, it is likely that in coming decades, it may exceed these critical values. In order to set deposition limits and avoid adverse effects of acidic deposition this approach can be applied in India too. Such approach is very useful, not only in abating pollution but also in devising means of cost optimal emission abatement strategies.

  17. CRITICAL CONFIGURATION AND PHYSICS MEASUREMENTS FOR BERYLLIUM REFLECTED ASSEMBLIES OF U(93.15)O2 FUEL RODS (1.506-CM PITCH)

    SciTech Connect

    Margaret A. Marshall

    2013-03-01

    Cadmium ratios were measured with enriched uranium metal foils at various locations in the assembly with the fuel tube at the 1.506-cm spacing. They are described in the following subsections. The experiment configuration was the same as the first critical configuration described in HEU-COMP-FAST-004 (Case 1). The experimenter placed 0.75-cm-diameter × 0.010-cm-thick 93.15%-235U-enriched uranium metal foils with and without 0.051-cm-thick cadmium covers at various locations in the core and top reflector. One part of the cadmium cover was cupshape and contained the uranium foil. The other part was a lid that fit over the exposed side of the foil when it was in the cup shaped section of the cover. As can be seen in the logbook, two runs were required to obtain all the measurements necessary for the cadmium ratio. The bare foil measurements within the top reflector were run first as part of the axial foil activation measurements. The results of this run are used for both the axial activation results and the cadmium ratios. Cadmium covered foils were then placed at the same location through the top reflector in a different run. Three pairs of bare and cadmium covered foils were also placed through the core tank. One pair was placed at the axial center of a fuel tube 11.35 cm from the center of the core. Two pairs of foils were placed on top of fuel tubes 3.02 and 12.06 cm from the center of the core. The activation of the uranium metal foils was measured after removal from the assembly using two lead shielded NaI scintillation detectors as follows. The NaI scintillators were carefully matched and had detection efficiencies for counting delayed-fission-product gamma rays with energies above 250 KeV within 5%. In all foil activation measurements, one foil at a specific location was used as a normalizing foil to remove the effects of the decay of fission products during the counting measurements with the NaI detectors. The normalization foil was placed on one Na

  18. CRITICAL CONFIGURATION AND PHYSICS MEASUREMENTS FOR BERYLLIUM REFLECTED ASSEMBLIES OF U(93.15)O2 FUEL RODS (1.506-CM PITCH AND 7-TUBE CLUSTERS)

    SciTech Connect

    Margaret A. Marshall

    2014-03-01

    Cadmium ratios were measured with enriched uranium metal foils at various locations in the assembly with the fuel tube at the 1.506-cm spacing. They are described in the following subsections. The experiment configuration was the same as the first critical configuration described in HEU-COMP-FAST-004 (Case 1). The experimenter placed 0.75-cm-diameter × 0.010-cm-thick 93.15%-235U-enriched uranium metal foils with and without 0.051-cm-thick cadmium covers at various locations in the core and top reflector. One part of the cadmium cover was cupshape and contained the uranium foil. The other part was a lid that fit over the exposed side of the foil when it was in the cup shaped section of the cover. As can be seen in the logbook, two runs were required to obtain all the measurements necessary for the cadmium ratio. The bare foil measurements within the top reflector were run first as part of the axial foil activation measurements. The results of this run are used for both the axial activation results and the cadmium ratios. Cadmium covered foils were then placed at the same location through the top reflector in a different run. Three pairs of bare and cadmium covered foils were also placed through the core tank. One pair was placed at the axial center of a fuel tube 11.35 cm from the center of the core. Two pairs of foils were placed on top of fuel tubes 3.02 and 12.06 cm from the center of the core. The activation of the uranium metal foils was measured after removal from the assembly using two lead shielded NaI scintillation detectors as follows. The NaI scintillators were carefully matched and had detection efficiencies for counting delayed-fission-product gamma rays with energies above 250 KeV within 5%. In all foil activation measurements, one foil at a specific location was used as a normalizing foil to remove the effects of the decay of fission products during the counting measurements with the NaI detectors. The normalization foil was placed on one Na

  19. Critical Configuration and Physics Measurements for Beryllium Reflected Assemblies of U(93.15)O₂ Fuel Rods (1.506-cm Pitch and 7-Tube Clusters)

    SciTech Connect

    Marshall, Margaret A.; Bess, John D.; Briggs, J. Blair; Murphy, Michael F.; Mihalczo, John T.

    2015-03-01

    Cadmium ratios were measured with enriched uranium metal foils at various locations in the assembly with the fuel tube at the 1.506-cm spacing. They are described in the following subsections. The experiment configuration was the same as the first critical configuration described in HEU-COMP-FAST-004 (Case 1). The experimenter placed 0.75-cm-diameter × 0.010-cm-thick 93.15%-235U-enriched uranium metal foils with and without 0.051-cm-thick cadmium covers at various locations in the core and top reflector. One part of the cadmium cover was cupshape and contained the uranium foil. The other part was a lid that fit over the exposed side of the foil when it was in the cup shaped section of the cover. As can be seen in the logbook, two runs were required to obtain all the measurements necessary for the cadmium ratio. The bare foil measurements within the top reflector were run first as part of the axial foil activation measurements. The results of this run are used for both the axial activation results and the cadmium ratios. Cadmium covered foils were then placed at the same location through the top reflector in a different run. Three pairs of bare and cadmium covered foils were also placed through the core tank. One pair was placed at the axial center of a fuel tube 11.35 cm from the center of the core. Two pairs of foils were placed on top of fuel tubes 3.02 and 12.06 cm from the center of the core. The activation of the uranium metal foils was measured after removal from the assembly using two lead shielded NaI scintillation detectors as follows. The NaI scintillators were carefully matched and had detection efficiencies for counting delayed-fission-product gamma rays with energies above 250 KeV within 5%. In all foil activation measurements, one foil at a specific location was used as a normalizing foil to remove the effects of the decay of fission products during the counting measurements with the NaI detectors. The normalization foil was placed on one Na

  20. Critical loads and H+ budgets of forest soils affected by air pollution from oil sands mining in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Jung, Kangho; Chang, Scott X.; Ok, Yong Sik; Arshad, M. A.

    2013-04-01

    We investigated the critical load (CL) and exceedance (EX) of sulfur (S) deposition, temporal changes in soil chemistry, and H+ budget of soils in plots dominated by Pinus banksiana (jack pine) or Populus tremuloides (trembling aspen, aspen) in two acid-sensitive watersheds to assess the risk of soil acidification by S emissions from oil sands mining in the Athabasca oil sands region (AOSR), Canada. The CLs and EXs were determined by two methods: one was based on bulk deposition and the other based on total deposition (as a sum of bulk deposition and interception deposition). The CLs ranged from 223 to 711 molc ha-1 yr-1 based on bulk deposition. Those values were similar to that obtained based on total deposition. However, EXs based on bulk deposition were significantly lower (p < 0.001) than those based on total deposition due to the relative increase of SO concentrations in interception deposition, indicating that EXs based on bulk deposition only could underestimate the risk of soil acidification in the AOSR. The S deposition did not exceed CLs in the long-term for both methods. The pH in the forest floor increased and available SO (as the sum of soluble and adsorbed SO) in the forest floor and surface mineral soils increased in both jack pine and aspen stands between 2005 and 2010. The H+ budget ranged from -289 to -130 molc ha-1 yr-1 in jack pine stands and from -510 to -371 molc ha-1 yr-1 in aspen stands. Our results suggest that 1) soils in the studied forest stands have recovered from acidification based on the increasing soil pH over time and the negative H+ budget, and 2) the risk of soil acidification should be assessed by CL and EX calculated based on total deposition.

  1. Synthesis of recent advances in critical loads research on impacts from atmospheric nitrogen deposition on terrestrial plant communities.

    NASA Astrophysics Data System (ADS)

    Clark, C.; Horn, K. J.; Thomas, R. Q.; Simkin, S.; Pardo, L. H.; Blett, T.; Lawrence, G. B.; Belyazid, S.; Phelan, J.

    2015-12-01

    Nitrogen (N) deposition is one of the primary threats to plant biodiversity world-wide after habitat destruction and climate change. As a primary limiting nutrient and contributor to soil acidification, N inputs have the capacity to alter ecosystems through several mechanisms. Up until now, there was very little detailed information on the impacts from this stressor at the species level, or how climate and edaphic factors could alter ecosystem sensitivity. Here we summarize and synthesize four major efforts, funded by EPA, USGS, USFS, and the NPS, which greatly advance our understanding of this stressor. These include (1) a national analysis of sensitivity to N deposition for 114 tree species, (2) a national analysis of impacts from N deposition on herbaceous species and how climate and soil factors modify that sensitivity, (3) a regional dynamic modeling study of impacts and recovery from N and S deposition for a dominant northeastern forest type under a range of future climate and deposition scenarios, and (4) a large assessment of impacts to streams, soils, and vegetation along the 2000+ mile stretch of the Appalachian Trail. Here we show many responses to this stressor for all taxonomic groups, with some species decreasing, some increasing, and some unaffected by N deposition. However, dozens of tree and herb species are negatively affected and are of particular concern for conservation purposes, with vulnerability being greatly affected by regional climate and local edaphic factors. Dynamic modeling suggests that, at least in some northeastern forests, recovery across a broad range of climate change and management scenarios is unlikely by 2100. The study along the Appalachian Trail, a beloved national recreation trail, echoes these findings, with stream, soils, and vegetation impacted across large percentages of sites, and only moderate capacity for recovery by 2100. In total, this work highlights several recent advances in the area of critical loads research

  2. Configuring load as a resource for competitive electricity markets--Review of demand response programs in the U.S. and around the world

    SciTech Connect

    Heffner, Grayson C.

    2002-09-01

    The restructuring of regional and national electricity markets in the U.S. and around the world has been accompanied by numerous problems, including generation capacity shortages, transmission congestion, wholesale price volatility, and reduced system reliability. These problems have created new opportunities for technologies and business approaches that allow load serving entities and other aggregators to control and manage the load patterns of wholesale and retail end-users they serve. Demand Response Programs, once called Load Management, have re-emerged as an important element in the fine-tuning of newly restructured electricity markets. During the summers of 1999 and 2001 they played a vital role in stabilizing wholesale markets and providing a hedge against generation shortfalls throughout the U.S.A. Demand Response Programs include ''traditional'' capacity reservation and interruptible/curtailable rates programs as well as voluntary demand bidding programs offered by either Load Serving Entities (LSEs) or regional Independent System Operators (ISOs). The Lawrence Berkeley National Lab (LBNL) has been monitoring the development of new types of Demand Response Programs both in the U.S. and around the world. This paper provides a survey and overview of the technologies and program designs that make up these emerging and important new programs.

  3. Module Configuration

    DOEpatents

    Oweis, Salah; D'Ussel, Louis; Chagnon, Guy; Zuhowski, Michael; Sack, Tim; Laucournet, Gaullume; Jackson, Edward J.

    2002-06-04

    A stand alone battery module including: (a) a mechanical configuration; (b) a thermal management configuration; (c) an electrical connection configuration; and (d) an electronics configuration. Such a module is fully interchangeable in a battery pack assembly, mechanically, from the thermal management point of view, and electrically. With the same hardware, the module can accommodate different cell sizes and, therefore, can easily have different capacities. The module structure is designed to accommodate the electronics monitoring, protection, and printed wiring assembly boards (PWAs), as well as to allow airflow through the module. A plurality of modules may easily be connected together to form a battery pack. The parts of the module are designed to facilitate their manufacture and assembly.

  4. Effects of design variables on the critical stresses of eye bars under load: an evaluation by photoelastic modeling

    SciTech Connect

    Scott, R.G.; Stone, J.C.

    1982-01-08

    Textbooks on machine design and other relevant handbooks have not approached in depth the problem of estimating the effects of major design variables on the critical stresses in eye-bar lugs used for heavy lifting. The critical stresses determined experimentally by the photoelastic modeling of design variations of geometry and pin clearance with and without a bushing between the pin and the lug are discussed. Experimental data are compared to values developed from theoretical analysis.

  5. Design and commissioning of a valve-regulated lead/acid battery energy-storage system for backing up critical environmental loads

    NASA Astrophysics Data System (ADS)

    Hunt, G. W.

    Momentary and sustained electrical power interruptions and voltage depressions represent two of the most difficult and important power quality and delivery problems that face many industrial and commercial users. There is a definite need at many industrial processing plants and commercial users of electrical power to have a dependable, efficient and controllable source of real and reactive power that is available instantly to support large electrical loads (greater than 5 MVA), even if the incoming utility a.c. connection is lost. When power is interrupted or lost, the results can be extremely disruptive for critical processes and cause lost production, costly downtime and loss of customer good will, and in certain industries, can lead to environmental damage through the release of toxic emissions into the air. Recently, this challenge was faced by GNB Technologies at its lead reclaiming and smelting facility in Vernon, CA, USA. This study describes a versatile, cost-effective, workable solution to the problem that has resulted in the design and installation of a 5 MVA, 3.5 MWh battery energy storage system (BESS) which provides uninterruptible power to the critical environmental control equipment throughout the plant. The BESS at Vernon provides the required power, combined with both voltage and frequency control, to allow the plant to tolerate disconnection from the utility grid without suffering unacceptable impacts on critical loads. The system also provides the company with a demand-side energy management system for conducting daily peak shaving of energy demand and, thereby, reduces its electrical bills.

  6. Observed Temperature Effects on Hourly Residential Electric LoadReduction in Response to an Experimental Critical Peak PricingTariff

    SciTech Connect

    Herter, Karen B.; McAuliffe, Patrick K.; Rosenfeld, Arthur H.

    2005-11-14

    The goal of this investigation was to characterize themanual and automated response of residential customers to high-price"critical" events dispatched under critical peak pricing tariffs testedin the 2003-2004 California Statewide Pricing Pilot. The 15-monthexperimental tariff gave customers a discounted two-price time-of-userate on 430 days in exchange for 27 critical days, during which the peakperiod price (2 p.m. to 7 p.m.) was increased to about three times thenormal time-of-use peak price. We calculated response by five-degreetemperature bins as the difference between peak usage on normal andcritical weekdays. Results indicatedthat manual response to criticalperiods reached -0.23 kW per home (-13 percent) in hot weather(95-104.9oF), -0.03 kW per home (-4 percent) in mild weather (60-94.9oF),and -0.07 kW per home (-9 percent) during cold weather (50-59.9oF).Separately, we analyzed response enhanced by programmable communicatingthermostats in high-use homes with air-conditioning. Between 90oF and94.9oF, the response of this group reached -0.56 kW per home (-25percent) for five-hour critical periods and -0.89 kW/home (-41 percent)for two-hour critical periods.

  7. Investigation of space shuttle vehicle 140C configuration orbiter (model 16-0) wheel well pressure loads in the Rockwell International 7.75 x 11 foot wind tunnel (OA143)

    NASA Technical Reports Server (NTRS)

    Mennell, R. C.

    1975-01-01

    Experimental aerodynamic investigations were conducted on a sting mounted .0405-scale representation of the 140C outer mold line space shuttle orbiter configuration in the Rockwell International 7.75 x 11.00 foot low speed wind tunnel. The primary test objectives were to define the orbiter wheel well pressure loading and its effects on landing gear thermal insulation and to investigate the pressure environment experienced by both the horizontal flight nose probe and air vent door probes. Steady state and dynamic pressure values were recorded in the orbiter nose gear well, left main landing gear well, horizontal flight nose probe, and both left and right air vent door probe. All steady state pressure levels were measured by Statham differential pressure transducers while dynamic pressure levels were recorded by Kulite high frequency response pressure sensors.

  8. 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

  9. Fingernail Configuration

    PubMed Central

    Jung, Jin Woo; Shin, Jun Ho; Kwon, Yu Jin; Hwang, Jae Ha; Lee, Sam Yong

    2015-01-01

    Background A number of conditions can alter a person's fingernail configuration. The ratio between fingernail width and length (W/L) is an important aesthetic criterion, and some underlying diseases can alter the size of the fingernail. Fingernail curvature can be altered by systemic disorders or disorders of the fingernail itself. Although the shape and curvature of the fingernail can provide diagnostic clues for various diseases, few studies have precisely characterized normal fingernail configuration. Methods We measured the W/L ratio of the fingernail, transverse fingernail curvature, hand length, hand breadth, and distal interphalangeal joint width in 300 volunteers with healthy fingernails. We also investigated whether age, sex, height, and handedness influenced the fingernail W/L ratio and transverse fingernail curvature. Results In women, fingernail W/L ratios were similar across all five fingers, and were lower than those in men. The highest value of transverse fingernail curvature was found in the thumb, followed by the index, middle, ring, and little fingers. Handedness and aging influenced transverse fingernail curvature, but not the fingernail W/L ratio. Fingernails were flatter on the dominant hand than on the non-dominant hand. The radius of transverse fingernail curvature increased with age, indicating that fingernails tended to flatten with age. Conclusions Our quantitative data on fingernail configuration can be used as a reference range for diagnosing various diseases and deformities of the fingernail, and for performing reconstructive or aesthetic fingernail surgery. PMID:26618124

  10. Earthquake damage potential and critical scour depth of bridges exposed to flood and seismic hazards under lateral seismic loads

    NASA Astrophysics Data System (ADS)

    Song, Shin-Tai; Wang, Chun-Yao; Huang, Wen-Hsiu

    2015-12-01

    Many bridges located in seismic hazard regions suffer from serious foundation exposure caused by riverbed scour. Loss of surrounding soil significantly reduces the lateral strength of pile foundations. When the scour depth exceeds a critical level, the strength of the foundation is insufficient to withstand the imposed seismic demand, which induces the potential for unacceptable damage to the piles during an earthquake. This paper presents an analytical approach to assess the earthquake damage potential of bridges with foundation exposure and identify the critical scour depth that causes the seismic performance of a bridge to differ from the original design. The approach employs the well-accepted response spectrum analysis method to determine the maximum seismic response of a bridge. The damage potential of a bridge is assessed by comparing the imposed seismic demand with the strengths of the column and the foundation. The versatility of the analytical approach is illustrated with a numerical example and verified by the nonlinear finite element analysis. The analytical approach is also demonstrated to successfully determine the critical scour depth. Results highlight that relatively shallow scour depths can cause foundation damage during an earthquake, even for bridges designed to provide satisfactory seismic performance.

  11. CRITICAL CONFIGURATION AND PHYSICS MEASUREMENTS FOR GRAPHITE REFLECTED ASSEMBLIES OF U(93.15)O2 FUEL RODS (1.506-CM PITCH)

    SciTech Connect

    Margaret A. Marshall

    2012-03-01

    A series of critical experiments were completed in 1962-1965 at Oak Ridge National Laboratory’s Critical Experiments Facility in support of the Medium-Power Reactor Experiments (MPRE) program. In the late 1950’s efforts were made to study “power plants for the production of electrical power in space vehicles”. The MPRE program was a part of those efforts and studied the feasibility of a stainless steel system, boiling potassium 1 MW(t), or about 140 kW(e), reactor. The program was carried out in [fiscal years] 1964, 1965, and 1966. A summary of the program’s effort was compiled in 1967. The delayed critical experiments were a mockup of a small, potassium-cooled space power reactor for validation of reactor calculations and reactor physics methods. Initial experiments, performed in November and December of 1962, consisted of a core of 253 unmoderated stainless steel tubes, each containing 26 UO2 fuel pellets, surrounded by a graphite reflector. Measurements were made to determine critical reflector arrangements, fission-rate distributions, and cadmium ratio distributions. Subsequent experiments used beryllium reflectors and also measured the reactivity for various materials placed in the core. “The [assemblies were built] on [a] vertical assembly machine so that the movable part was the core and bottom reflector.” The first experiment in the series was evaluated in HEU-COMP-FAST-001. It had the 253 fuel tubes packed tightly into a 22.87 cm outside diameter (OD) core tank (References 1 and 2). The second experiment in the series, performed in early 1963, which is studied in this evaluation, had the 253 fuel tubes at a 1.506-cm triangular lattice in a 25.96 cm OD core tank and graphite reflectors on all sides. The experiment has been determined to represent an acceptable benchmark experiment. Information for this evaluation was compiled from published reports on all three parts of the experimental series (Reference 1-5) and the experimental logbook as

  12. Analytical method development for powder characterization: Visualization of the critical drug loading affecting the processability of a formulation for direct compression.

    PubMed

    Hirschberg, Cosima; Sun, Changquan Calvin; Rantanen, Jukka

    2016-09-01

    Characterization of particulate systems (powders) is one of the remaining scientific challenges. Evaluation of powder behaviour is often empirical and the decision-making processes are experience-based. There is a need for development of analytical instrumentation enabling more fundamental understanding of powder behaviour. Flowability and tabletability, two key factors in commercial scale manufacturing of tablets with direct compression (DC) approach, were analysed for formulations containing increasing amounts of several model active pharmaceutical ingredients (APIs). Flowability was investigated using a ring shear tester and tablets were prepared at four different compression pressures using a single punch tablet press. Thereby, a material sparing screening approach was developed to estimate the influence of APIs on behaviour of a given DC formulation. Additionally, this approach is useful for estimating the low threshold amount of API (wt%), at which the properties of an API start affecting the powder behaviour of a given formulation (API-excipient mixture). This threshold will be referred to as critical drug loading. The flowability of microcrystalline cellulose (reference grade pH 102) was used as a threshold for adequate flowability of model formulations. The threshold for tablet tensile strength was set to 2MPa. Simultaneous visual presentation of both- flowability and tabletability were used for a fast evaluation of manufacturability of a given formulation. The results confirmed that flowability is more sensitive to drug loading than tabletability, and that the critical drug loading for a DC formulation is strongly affected by particulate properties of API. For example, decreasing the particle size of paracetamol led to rapid decrease in flowability index, whereas the tabletability was not affected. PMID:27368089

  13. Combined impacts of precipitation and temperature on diffuse phosphorus pollution loading and critical source area identification in a freeze-thaw area.

    PubMed

    Wei, Peng; Ouyang, Wei; Hao, Fanghua; Gao, Xiang; Yu, Yongyong

    2016-05-15

    The loss of diffuse phosphorus (P) presented different characteristics in the freeze-thaw area due to the combined impacts of precipitation and temperature, which caused spatiotemporal variations of the critical source area of diffuse P (CSAP). The temperature and precipitation classification (TPC) method was proposed to identify the spatiotemporal characteristics of the CSAP in the cold area, and each year was divided into a freeze-thaw season and a growing season according to the average monthly temperature. The Soil and Water Assessment Tool (SWAT) provided the spatiotemporal patterns of the diffuse P loads. The years were also reclassified into dry, normal and wet years according to the annual precipitation levels. The CSAP with the 1st cumulative load level shared 9.68% of the same area between the two seasons, which had dry land as the dominant land use with direct P fertilization. The spatial distributions of the potential areas and the CSAP with the 2nd cumulative load level were more sensitive to the variation in temperature, which had 30.8%-46.1% of unvaried area between seasons. The cumulative load level analysis indicated that 14 subbasins in the freeze-thaw season and 7 subbasins in the growing season, which covered 61.2% and 48.6% of the total basin area, respectively, changed with the traditional CSAP identification among dry, normal and wet years. The fluctuation level analysis was carried out to compare the distributional difference of the CSAP and the potential areas between the TPC method and the traditional method, which highlighted the advantages of the TPC method. The results would be useful in identifying the distribution of the CSAP in cold areas, which improved the efficiency of diffuse pollution control. PMID:26970198

  14. Computational methods for predicting the response of critical as-built infrastructure to dynamic loads (architectural surety)

    SciTech Connect

    Preece, D.S.; Weatherby, J.R.; Attaway, S.W.; Swegle, J.W.; Matalucci, R.V.

    1998-06-01

    Coupled blast-structural computational simulations using supercomputer capabilities will significantly advance the understanding of how complex structures respond under dynamic loads caused by explosives and earthquakes, an understanding with application to the surety of both federal and nonfederal buildings. Simulation of the effects of explosives on structures is a challenge because the explosive response can best be simulated using Eulerian computational techniques and structural behavior is best modeled using Lagrangian methods. Due to the different methodologies of the two computational techniques and code architecture requirements, they are usually implemented in different computer programs. Explosive and structure modeling in two different codes make it difficult or next to impossible to do coupled explosive/structure interaction simulations. Sandia National Laboratories has developed two techniques for solving this problem. The first is called Smoothed Particle Hydrodynamics (SPH), a relatively new gridless method comparable to Eulerian, that is especially suited for treating liquids and gases such as those produced by an explosive. The SPH capability has been fully implemented into the transient dynamics finite element (Lagrangian) codes PRONTO-2D and -3D. A PRONTO-3D/SPH simulation of the effect of a blast on a protective-wall barrier is presented in this paper. The second technique employed at Sandia National Laboratories uses a relatively new code called ALEGRA which is an ALE (Arbitrary Lagrangian-Eulerian) wave code with specific emphasis on large deformation and shock propagation. ALEGRA is capable of solving many shock-wave physics problems but it is especially suited for modeling problems involving the interaction of decoupled explosives with structures.

  15. Enabling the Distributed Generation Market of High Temperature Fuel Cell and Absorption Chiller Systems to Support Critical and Commercial Loads

    NASA Astrophysics Data System (ADS)

    DiMola, Ashley M.

    Buildings account for over 18% of the world's anthropogenic Greenhouse Gas (GHG) emissions. As a result, a technology that can offset GHG emissions associated with buildings has the potential to save over 9 Giga-tons of GHG emissions per year. High temperature fuel cell and absorption chiller (HTFC/AC) technology offers a relatively low-carbon option for meeting cooling and electric loads for buildings while producing almost no criteria pollutants. GHG emissions in the state of California would decrease by 7.48 million metric tons per year if every commercial building in the State used HTFC/AC technology to meet its power and cooling requirements. In order to realize the benefits of HTFC/AC technology on a wide scale, the distributed generation market needs to be exposed to the technology and informed of its economic viability and real-world potential. This work characterizes the economics associated with HTFC/AC technology using select scenarios that are representative of realistic applications. The financial impacts of various input factors are evaluated and the HTFC/AC simulations are compared to the economics of traditional building utilities. It is shown that, in addition to the emissions reductions derived from the systems, HTFC/AC technology is financially preferable in all of the scenarios evaluated. This work also presents the design of a showcase environment, centered on a beta-test application, that presents (1) system operating data gathered using a custom data acquisition module, and (2) HTFC/AC technology in a clear and approachable manner in order to serve the target audience of market stakeholders.

  16. Characterizing the uncertainty in holddown post load measurements

    NASA Technical Reports Server (NTRS)

    Richardson, J. A.; Townsend, J. S.

    1993-01-01

    In order to understand unexpectedly erratic load measurements in the launch-pad supports for the space shuttle, the sensitivities of the load cells in the supports were analyzed using simple probabilistic techniques. NASA engineers use the loads in the shuttle's supports to calculate critical stresses in the shuttle vehicle just before lift-off. The support loads are measured with 'load cells' which are actually structural components of the mobile launch platform which have been instrumented with strain gauges. Although these load cells adequately measure vertical loads, the horizontal load measurements have been erratic. The load measurements were simulated in this study using Monte Carlo simulation procedures. The simulation studies showed that the support loads are sensitive to small deviations in strain and calibration. In their current configuration, the load cells will not measure loads with sufficient accuracy to reliably calculate stresses in the shuttle vehicle. A simplified model of the holddown post (HDP) load measurement system was used to study the effect on load measurement accuracy for several factors, including load point deviations, gauge heights, and HDP geometry.

  17. The influence of the modulus-density relationship and the material mapping method on the simulated mechanical response of the proximal femur in side-ways fall loading configuration.

    PubMed

    Helgason, B; Gilchrist, S; Ariza, O; Vogt, P; Enns-Bray, W; Widmer, R P; Fitze, T; Pálsson, H; Pauchard, Y; Guy, P; Ferguson, S J; Cripton, P A

    2016-07-01

    Contributing to slow advance of finite element (FE) simulations for hip fracture risk prediction, into clinical practice, could be a lack of consensus in the biomechanics community on how to map properties to the models. Thus, the aim of the present study was first, to systematically quantify the influence of the modulus-density relationship (E-ρ) and the material mapping method (MMM) on the predicted mechanical response of the proximal femur in a side-ways fall (SWF) loading configuration and second, to perform a model-to-model comparison of the predicted mechanical response within the femoral neck for all the specimens tested in the present study, using three different modelling techniques that have yielded good validation outcome in terms of surface strain prediction and whole bone response according to the literature. We found the outcome to be highly dependent on both the E-ρ relationship and the MMM. In addition, we found that the three modelling techniques that have resulted in good validation outcome in the literature yielded different principal strain prediction both on the surface as well as internally in the femoral neck region of the specimens modelled in the present study. We conclude that there exists a need to carry out a more comprehensive validation study for the SWF loading mode to identify which combination of MMMs and E-ρ relationship leads to the best match for whole bone and local mechanical response. The MMMs tested in the present study have been made publicly available at https://simtk.org/home/mitk-gem. PMID:27185044

  18. Influence of the overall stiffness of a load-bearing porous titanium implant on bone ingrowth in critical-size mandibular bone defects in sheep.

    PubMed

    Schouman, T; Schmitt, M; Adam, C; Dubois, G; Rouch, P

    2016-06-01

    The aim of this work was to assess the influence of reduction of the apparent mechanical properties of fully load-bearing porous titanium implants used in mandibular bone defects. Segmental 18mm long bone defects were created bilaterally in the lower jaws of adult ewes. One group of 6 ewes (group A) was treated with load-bearing 'rigid' (high stiffness) porous implants on the right side, and with control on the left side. A second group of 6 ewes (group B) was treated with 'flexible' porous and control implants exhibiting apparent mechanical properties ten times lower than the rigid implants. The mechanical behavior of the reconstructed hemi-mandibles was assessed by cantilever testing and bone ingrowth into the segmental defects was assessed by BV/TV measurement within the implant using micro-CT 12 weeks after implantation. A significantly higher rigidity was identified for porous implants compared with control implants at the anterior interface in group B. BV/TV of porous implants was significantly higher than that of control implants in group A. BV/TV differences were significant between porous and control implants in group B and were homogeneous along the main axis. Significantly higher BV/TV was identified in most sub-volumes of group B porous implants compared with group A. This work highlights the critical importance of the tuning of scaffolds to promote bone ingrowth with reference to the local strains occurring within the porous scaffold, which in this application was achieved using fully load-bearing low-stiffness porous titanium implants. PMID:26999620

  19. LOADING DEVICE

    DOEpatents

    Ohlinger, L.A.

    1958-10-01

    A device is presented for loading or charging bodies of fissionable material into a reactor. This device consists of a car, mounted on tracks, into which the fissionable materials may be placed at a remote area, transported to the reactor, and inserted without danger to the operating personnel. The car has mounted on it a heavily shielded magazine for holding a number of the radioactive bodies. The magazine is of a U-shaped configuration and is inclined to the horizontal plane, with a cap covering the elevated open end, and a remotely operated plunger at the lower, closed end. After the fissionable bodies are loaded in the magazine and transported to the reactor, the plunger inserts the body at the lower end of the magazine into the reactor, then is withdrawn, thereby allowing gravity to roll the remaining bodies into position for successive loading in a similar manner.

  20. Aquarius main structure configuration

    NASA Astrophysics Data System (ADS)

    Eremenko, A.

    The Aquarius/SAC-D Observatory is a joint US-Argentine mission to map the salinity at the ocean surface. This information is critical to improving our understanding of two major components of Earth's climate system - the water cycle and ocean circulation. By measuring ocean salinity from space, the Aquarius/SAC-D Mission will provide new insights into how the massive natural exchange of freshwater between the ocean, atmosphere and sea ice influences ocean circulation, weather and climate. Aquarius is the primary instrument on the SAC-D spacecraft. It consists of a Passive Microwave Radiometer to detect the surface emission that is used to obtain salinity and an Active Scatterometer to measure the ocean waves that affect the precision of the salinity measurement. The Aquarius Primary Structure houses instrument electronics, feed assemblies, and supports a deployable boom with a 2.5 m Reflector, and provides the structural interface to the SAC-D Spacecraft. The key challenge for the Aquarius main structure configuration is to satisfy the needs of component accommodations, ensuring that the instrument can meet all operational, pointing, environmental, and launch vehicle requirements. This paper describes the evolution of the Aquarius main structure configuration, the challenges of balancing the conflicting requirements, and the major configuration driving decisions and compromises.

  1. Operational experience and performance characteristics of a valve-regulated lead-acid battery energy-storage system for providing the customer with critical load protection and energy-management benefits at a lead-recycling plant

    NASA Astrophysics Data System (ADS)

    Hunt, G. W.

    The Power Control Division of GNB Technologies, commissioned on May 13, 1996 a new facility which houses a 5-MW battery energy-storage system (BESS) at GNB's Lead Recycling Centre in Vernon, CA. When the plant loses utility power (which typically happens two or three times a year), the BESS will provide up to 5 MW of power at 4160 VAC in support of all the plant loads. Since the critical loads are not isolated, it is necessary to carry the entire plant load (maximum of 5 MVA) for a short period immediately following an incident until non-critical loads have been automatically shed. Plant loading typically peaks at 3.5 MVA with critical loads of about 2.1 MVA. The BESS also provides the manufacturing plant with customer-side-of-the-meter energy management options to reduce its energy demand during peak periods of the day. The BESS has provided a reduction in monthly electric bills through daily peak-shaving. By design, the battery can provide up to 2.5 MWh of energy and still retain 2.5 MWh of capacity in reserve to handle the possibility of a power outage in protecting the critical loads for up to 1 h. By storing energy from the utility during off-peak hours of the night in the batteries when the cost is low (US4.5¢ per kWh), GNB can then discharge this energy during high demand periods of the day (US14.50 per kW). For example, by reducing its peak demand by 300 kW, the lead-recycling centre can save over US4000 per month in its electric bills. The BESS at Vernon represents a first large-scale use of valve-regulated lead-acid batteries in such a demanding application. This paper presents a summary of the operational experience and performance characteristics of the BESS over the past 2 years.

  2. Data on respiratory variables in critically ill patients with acute respiratory failure placed on proportional assist ventilation with load adjustable gain factors (PAV+).

    PubMed

    Georgopoulos, Dimitris; Xirouchaki, Nectaria; Tzanakis, Nikolaos; Younes, Magdy

    2016-09-01

    The data show respiratory variables in 108 critically ill patients with acute respiratory failure placed on proportional assist ventilation with load adjustable gain factors (PAV+) after at least 36 h on passive mechanical ventilation. PAV+ was continued for 48 h until the patients met pre-defined criteria either for switching to controlled modes or for breathing without ventilator assistance. Data during passive mechanical ventilation and during PAV+ are reported. Data are acquired from the whole population, as well as from patients with and without acute respiratory distress syndrome. The reported variables are tidal volume, driving pressure (ΔP, the difference between static end-inspiratory plateau pressure and positive end-expiratory airway pressure), respiratory system compliance and resistance, and arterial blood gasses. The data are supplemental to our original research article, which described individual ΔP in these patients and examined how it related to ΔP when the same patients were ventilated with passive mechanical ventilation using the currently accepted lung-protective strategy "Driving pressure during assisted mechanical ventilation. Is it controlled by patient brain?" [1]. PMID:27358909

  3. Evaluation of Cask Drop Criticality Issues at K Basin

    SciTech Connect

    GOLDMANN, L.H.

    2000-01-24

    An analysis of ability of Multi-canister Overpack (MCO) to withstand drops at K Basin without exceeding the criticality design requirements. Report concludes the MCO will function acceptably. The spent fuel currently residing in the 105 KE and 105 KW storage basins will be placed in fuel storage baskets which will be loaded into the MCO cask assembly. During the basket loading operations the MCO cask assembly will be positioned near the bottom of the south load out pit (SLOP). The loaded MCO cask will be lifted from the SLOP transferred to the transport trailer and delivered to the Cold Vacuum Drying Facility (CVDF). In the wet condition there is a potential for criticality problems if significant changes in the designed fuel configurations occur. The purpose of this report is to address structural issues associated with criticality design features for MCO cask drop accidents in the 105 KE and 105 KW facilities.

  4. DICE: Database for the International Criticality Safety Benchmark Evaluation Program Handbook

    SciTech Connect

    Nouri, Ali; Nagel, Pierre; Briggs, J. Blair; Ivanova, Tatiana

    2003-09-15

    The 2002 edition of the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments' (ICSBEP Handbook) spans more than 26 000 pages and contains 330 evaluations with benchmark specifications for 2881 critical or near-critical configurations. With such a large content, it became evident that the users needed more than a broad and qualitative classification of experiments to make efficient use of the ICSBEP Handbook. This paper describes the features of Database for the International Handbook of Evaluated Criticality Safety Benchmark Experiments (DICE), which is a database for the ICSBEP Handbook. The DICE program contains a relational database loaded with selected information from each configuration and a users' interface that enables one to query the database and to extract specific parameters. Summary descriptions of each experimental configuration can also be obtained. In addition, plotting capabilities provide the means of comparing neutron spectra and sensitivity coefficients for a set of configurations.

  5. Critical material attributes (CMAs) of strip films loaded with poorly water-soluble drug nanoparticles: I. Impact of plasticizer on film properties and dissolution.

    PubMed

    Krull, Scott M; Patel, Hardik V; Li, Meng; Bilgili, Ecevit; Davé, Rajesh N

    2016-09-20

    Recent studies have demonstrated polymer films to be a promising platform for delivery of poorly water-soluble drug particles. However, the impact of critical material attributes, for example plasticizer, on the properties of and drug release from such films has yet to be investigated. In response, this study focuses on the impact of plasticizer and plasticizer concentration on properties and dissolution rate of polymer films loaded with poorly water-soluble drug nanoparticles. Glycerin, triacetin, and polyethylene glycol were selected as film plasticizers. Griseofulvin was used as a model Biopharmaceutics Classification System class II drug and hydroxypropyl methylcellulose was used as a film-forming polymer. Griseofulvin nanoparticles were prepared via wet stirred media milling in aqueous suspension. A depression in film glass transition temperature was observed with increasing plasticizer concentration, along with a decrease in film tensile strength and an increase in film elongation, as is typical of plasticizers. However, the type and amount of plasticizer necessary to produce strong yet flexible films had no significant impact on the dissolution rate of the films, suggesting that film mechanical properties can be effectively manipulated with minimal impact on drug release. Griseofulvin nanoparticles were successfully recovered upon redispersion in water regardless of plasticizer or content, even after up to 6months' storage at 40°C and 75% relative humidity, which contributed to similar consistency in dissolution rate after 6months' storage for all films. Good content uniformity (<4% R.S.D. for very small film sample size) was also maintained across all film formulations. PMID:27402100

  6. Wind-tunnel investigation of aerodynamic performance, steady amd vibratory loads, surface temperatures, and acoustic characteristics of a large-scale twin-engine upper-surface blown jet-flap configuration

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Static and wind-on tests were conducted to determine the aerodynamic characteristics of and the effects of jet impingement on the wing of a large scale upper surface blown configuration powered with an actual turbine engine. The wing and flaps were instrumented with experimental dual-sensing transducer units consisting of a fluctuating pressure gage, a vibratory accelerometer, and a surface mounted alumel thermocouple. Noise directivity and spectral content measurements were obtained for various flap configurations and various engine thrust settings to provide baseline noise data for other upper surface blown configurations.

  7. CFD Data Generation Process for Nonlinear Loads

    NASA Technical Reports Server (NTRS)

    Arslan, Alan; Magee, Todd; Unger, Eric; Hartwich, Peter; Agrawal, Shreekant; Giesing, Joseph; Bharadvaj, Bala; Chaderjian, Neal; Murman, Scott

    1999-01-01

    This paper discusses the development of a process to generate a CFD database for the non-linear loads process capability for critical loads evaluation at Boeing Long Beach. The CFD simulations were performed for wing/body configurations at high angles of attack and Reynolds numbers with transonic and elastic deflection effects. Convergence criteria had to be tailored for loads applications rather than the usual drag performance. The time-accurate approach was subsequently adopted in order to improve convergence and model possible unsteadiness in the flowfield. In addition, uncertainty issues relating to the turbulence model and grid resolution in areas of high vortical flows were addressed and investigated for one of the cases.

  8. Constrained simultaneous multi-state reconfigurable wing structure configuration optimization

    NASA Astrophysics Data System (ADS)

    Snyder, Matthew

    A reconfigurable aircraft is capable of in-flight shape change to increase mission performance or provide multi-mission capability. Reconfigurability has always been a consideration in aircraft design, from the Wright Flyer, to the F-14, and most recently the Lockheed-Martin folding wing concept. The Wright Flyer used wing-warping for roll control, the F-14 had a variable-sweep wing to improve supersonic flight capabilities, and the Lockheed-Martin folding wing demonstrated radical in-flight shape change. This dissertation will examine two questions that aircraft reconfigurability raises, especially as reconfiguration increases in complexity. First, is there an efficient method to develop a light weight structure which supports all the loads generated by each configuration? Second, can this method include the capability to propose a sub-structure topology that weighs less than other considered designs? The first question requires a method that will design and optimize multiple configurations of a reconfigurable aerostructure. Three options exist, this dissertation will show one is better than the others. Simultaneous optimization considers all configurations and their respective load cases and constraints at the same time. Another method is sequential optimization which considers each configuration of the vehicle one after the other - with the optimum design variable values from the first configuration becoming the lower bounds for subsequent configurations. This process repeats for each considered configuration and the lower bounds update as necessary. The third approach is aggregate combination — this method keeps the thickness or area of each member for the most critical configuration, the configuration that requires the largest cross-section. This research will show that simultaneous optimization produces a lower weight and different topology for the considered structures when compared to the sequential and aggregate techniques. To answer the second question

  9. NCSX Machine Configuration Design Progress

    NASA Astrophysics Data System (ADS)

    Neilson, G. H.; Brooks, A.; Johnson, D.; Kugel, H.; Majeski, R.; Reiersen, W.; Zarnstorff, M.; Berry, L.; Cole, M.; Hirshman, S.; Nelson, B.; Strickler, D.

    2000-10-01

    A new experimental facility, the National Compact Stellarator Experiment, is being designed to support the development of high-beta, low aspect-ratio stellarators. To fulfill its mission, the facility design is required to: 1)be based on a stellarator magnetic configuration which enables it to address reactor physics issues, 2)have high probability of achieving its physics mission within the uncertainties of present-day physics models, and 3)provide access for experimental tools such as plasma heating systems and diagnostics. The most critical machine component is the coil system which determines the plasma configuration and its properties. To gain an understanding of the practical implications of the mission requirements and determine the optimum approach to satisfying them, a range of coil configuration options was investigated. To address requirement 1, each option was designed to reconstruct a common stellarator plasma configuration with desired stability and transport properties. To mitigate mission risk (requirement 2), magnetic configuration flexibility features, e.g., coils for inductive current drive and axisymmetric field shaping and an operating space exceeding the nominal magnetic field and pulse-length requirements, were included in all designs. To implement requirement 3, port access requirements for neutral-beam and radiofrequency heating systems, a diagnostic array, and vacuum pumping were determined and these were used to analyze the various designs. Differential costs were evaluated to provide a basis for assessing benefit/cost.

  10. Methodology for consideration of specific features of combined-cycle plants with the optimal sharing of the thermal and the electric loads at combined heat power plants with equipment of a complex configuration

    NASA Astrophysics Data System (ADS)

    Arakelyan, E. K.; Andriushin, A. V.; Burtsev, S. Y.; Andriushin, K. A.; Hurshudyan, S. R.

    2015-05-01

    When a combined-cycle power plant operates as part of a combined heat power plant, the optimal load-sharing among the power-generating units of the station is complicated owing to specific features of operating a combined-cycle power plant, viz., the dependence of its adjustment range values on the outdoor air temperature, degradation of the ecological and economic performance figures under underloading conditions, possibility of load-sharing between the gas turbines, and a high flexibility. A method for optimal sharing of the load among the power-generating plants of combined heat power plants is proposed that takes into consideration the above features of the combined-cycle power plants. The combined heat power plant is divided into "equivalent" units according to the group power supply points. The first step is the intra-unit optimization over the entire variation range of the thermal and electric loads to achieve the best energy performance of the "equivalent" unit. The second step is the optimization of the load-sharing among the "equivalent" units.

  11. Operational Dynamic Configuration Analysis

    NASA Technical Reports Server (NTRS)

    Lai, Chok Fung; Zelinski, Shannon

    2010-01-01

    Sectors may combine or split within areas of specialization in response to changing traffic patterns. This method of managing capacity and controller workload could be made more flexible by dynamically modifying sector boundaries. Much work has been done on methods for dynamically creating new sector boundaries [1-5]. Many assessments of dynamic configuration methods assume the current day baseline configuration remains fixed [6-7]. A challenging question is how to select a dynamic configuration baseline to assess potential benefits of proposed dynamic configuration concepts. Bloem used operational sector reconfigurations as a baseline [8]. The main difficulty is that operational reconfiguration data is noisy. Reconfigurations often occur frequently to accommodate staff training or breaks, or to complete a more complicated reconfiguration through a rapid sequence of simpler reconfigurations. Gupta quantified a few aspects of airspace boundary changes from this data [9]. Most of these metrics are unique to sector combining operations and not applicable to more flexible dynamic configuration concepts. To better understand what sort of reconfigurations are acceptable or beneficial, more configuration change metrics should be developed and their distribution in current practice should be computed. This paper proposes a method to select a simple sequence of configurations among operational configurations to serve as a dynamic configuration baseline for future dynamic configuration concept assessments. New configuration change metrics are applied to the operational data to establish current day thresholds for these metrics. These thresholds are then corroborated, refined, or dismissed based on airspace practitioner feedback. The dynamic configuration baseline selection method uses a k-means clustering algorithm to select the sequence of configurations and trigger times from a given day of operational sector combination data. The clustering algorithm selects a simplified

  12. 14 CFR 23.301 - Loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.301 Loads. (a... to determine load intensities and distribution on canard and tandem wing configurations must...

  13. Cold-air investigation of a 31/2-stage fan-drive turbine with a stage loading factor of 4 designed for an integral lift engine. 2: Performance of 2-, 3- and 3 1/2-stage configurations

    NASA Technical Reports Server (NTRS)

    Whitney, W. J.

    1977-01-01

    The stage work distribution among the three stages was very close to the design value. The specific work output-mass flow characteristics of the three stages were closely matched. The efficiency of the 3 1/2 stage turbine at design specific work output and design speed was within 0.008 of the estimated value, and this agreement was felt to demonstrate the adequacy of the prediction method in the high stage loading factor regime.

  14. Computer Lab Configuration.

    ERIC Educational Resources Information Center

    Wodarz, Nan

    2003-01-01

    Describes the layout and elements of an effective school computer lab. Includes configuration, storage spaces, cabling and electrical requirements, lighting, furniture, and computer hardware and peripherals. (PKP)

  15. Self-Configuring Network Monitor

    Energy Science and Technology Software Center (ESTSC)

    2004-05-01

    Self-Configuring Network Monitor (SCNM) is a passive monitoring that can collect packet headers from any point in a network path. SCNM uses special activation packets to automatically activate monitors deployed at the layer three ingress and egress routers of the wide-area network, and at critical points within the site networks. Monitoring output data is sent back to the application data source or destination host. No modifications are required to the application or network routing infrastructuremore » in order to activate monitoring of traffic for an application. This ensures that the monitoring operation does not add a burden to the networks administrator.« less

  16. Elastomeric load sharing device

    NASA Technical Reports Server (NTRS)

    Isabelle, Charles J. (Inventor); Kish, Jules G. (Inventor); Stone, Robert A. (Inventor)

    1992-01-01

    An elastomeric load sharing device, interposed in combination between a driven gear and a central drive shaft to facilitate balanced torque distribution in split power transmission systems, includes a cylindrical elastomeric bearing and a plurality of elastomeric bearing pads. The elastomeric bearing and bearing pads comprise one or more layers, each layer including an elastomer having a metal backing strip secured thereto. The elastomeric bearing is configured to have a high radial stiffness and a low torsional stiffness and is operative to radially center the driven gear and to minimize torque transfer through the elastomeric bearing. The bearing pads are configured to have a low radial and torsional stiffness and a high axial stiffness and are operative to compressively transmit torque from the driven gear to the drive shaft. The elastomeric load sharing device has spring rates that compensate for mechanical deviations in the gear train assembly to provide balanced torque distribution between complementary load paths of split power transmission systems.

  17. Configuration of a shear web based actuation system

    NASA Astrophysics Data System (ADS)

    Natterer, Franz Josef; Monner, Hans-Peter

    2010-04-01

    Shape adaptive systems and structural configurations are necessary to fulfill the demands of a future unmanned aerial vehicle structure. Predominantly the present approaches are based on a passive load-bearing structure having smart actuation systems deforming the passive structural configuration elastically in the wanted shape. Therefore the actuation system can be based on discrete actuators, like electrically driven motors using gearing systems to transform the displacement into the structure or on smart material configurations placed on the load bearing passive structure, deforming the structure within the elastic region into the wanted shape. Using smart materials within load-bearing structures, elastic and static strength properties vary between passive and active structures. Matching these properties is a great challenge for future structural configurations. This is a successful approach for certain applications, e.g. smart rotor blade. The availability of two-dimensional smart actuator configurations with distinct actuation orientation allows the definition of a distinct load bearing active structure. Therefore the so called "web" of a spar-equivalent configuration was substituted by such a smart material actuator also known as macro fiber composite (MFC). Activating the web of the active cantilevered spar-configuration is resulting in a free end displacement. The main advantage lies in the fact that this approach will allow larger active displacements in comparison to a passive structural configuration with applied smart material actuators. Within the paper the process of developing the shear web based actuation system with configuration details will be illustrated and future steps will be proposed.

  18. Configuration Management Process Assessment Strategy

    NASA Technical Reports Server (NTRS)

    Henry, Thad

    2014-01-01

    Purpose: To propose a strategy for assessing the development and effectiveness of configuration management systems within Programs, Projects, and Design Activities performed by technical organizations and their supporting development contractors. Scope: Various entities CM Systems will be assessed dependent on Project Scope (DDT&E), Support Services and Acquisition Agreements. Approach: Model based structured against assessing organizations CM requirements including best practices maturity criteria. The model is tailored to the entity being assessed dependent on their CM system. The assessment approach provides objective feedback to Engineering and Project Management of the observed CM system maturity state versus the ideal state of the configuration management processes and outcomes(system). center dot Identifies strengths and risks versus audit gotcha's (findings/observations). center dot Used "recursively and iteratively" throughout program lifecycle at select points of need. (Typical assessments timing is Post PDR/Post CDR) center dot Ideal state criteria and maturity targets are reviewed with the assessed entity prior to an assessment (Tailoring) and is dependent on the assessed phase of the CM system. center dot Supports exit success criteria for Preliminary and Critical Design Reviews. center dot Gives a comprehensive CM system assessment which ultimately supports configuration verification activities.*

  19. Load cell

    DOEpatents

    Spletzer, Barry L.

    2001-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs which can be combined to determine any one of the six general load components.

  20. Load cell

    DOEpatents

    Spletzer, B.L.

    1998-12-15

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components. 16 figs.

  1. Load cell

    DOEpatents

    Spletzer, Barry L.

    1998-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components.

  2. FEL phased array configurations

    NASA Astrophysics Data System (ADS)

    Shellan, Jeffrey B.

    1986-01-01

    The advantages and disadvantages of various phased array and shared aperture concepts for FEL configurations are discussed. Consideration is given to the characteristics of intra- and inter-micropulse phasing; intra-macropulse phasing; an internal coupled resonator configuration; and an injection locked oscillator array. The use of a master oscillator power amplifier (MOPA) configuration with multiple or single master oscillators for FELs is examined. The venetian blind, rotating plate, single grating, and grating rhomb shared aperture concepts are analyzed. It is noted that the shared aperture approach using a grating rhomb and the MOPA concept with a single master oscillator and a coupled resonator are useful for FEL phased array configurations; and the MOPA concept is most applicable.

  3. Critical review of the trailing edge condition in steady and unsteady flow. Blade flutter in compressors and fans: Numerical simulation of the aerodynamic loading

    NASA Technical Reports Server (NTRS)

    Radwan, S. F.; Rockwell, D. O.; Johnson, S. H.

    1982-01-01

    Existing interpretations of the trailing edge condition, addressing both theoretical and experimental works in steady, as well as unsteady flows are critically reviewed. The work of Kutta and Joukowski on the trailing edge condition in steady flow is reviewed. It is shown that for most practical airfoils and blades (as in the case of most turbomachine blades), this condition is violated due to rounded trailing edges and high frequency effects, the flow dynamics in the trailing edge region being dominated by viscous forces; therefore, any meaningful modelling must include viscous effects. The question of to what extent the trailing edge condition affects acoustic radiation from the edge is raised; it is found that violation of the trailing edge condition leads to significant sound diffraction at the tailing edge, which is related to the problem of noise generation. Finally, various trailing edge conditions in unsteady flow are discussed, with emphasis on high reduced frequencies.

  4. ION Configuration Editor

    NASA Technical Reports Server (NTRS)

    Borgen, Richard L.

    2013-01-01

    The configuration of ION (Inter - planetary Overlay Network) network nodes is a manual task that is complex, time-consuming, and error-prone. This program seeks to accelerate this job and produce reliable configurations. The ION Configuration Editor is a model-based smart editor based on Eclipse Modeling Framework technology. An ION network designer uses this Eclipse-based GUI to construct a data model of the complete target network and then generate configurations. The data model is captured in an XML file. Intrinsic editor features aid in achieving model correctness, such as field fill-in, type-checking, lists of valid values, and suitable default values. Additionally, an explicit "validation" feature executes custom rules to catch more subtle model errors. A "survey" feature provides a set of reports providing an overview of the entire network, enabling a quick assessment of the model s completeness and correctness. The "configuration" feature produces the main final result, a complete set of ION configuration files (eight distinct file types) for each ION node in the network.

  5. Nonlinear Aeroelastic Analysis of Joined-Wing Configurations

    NASA Astrophysics Data System (ADS)

    Cavallaro, Rauno

    Aeroelastic design of joined-wing configurations is yet a relatively unexplored topic which poses several difficulties. Due to the overconstrained nature of the system combined with structural geometric nonlinearities, the behavior of Joined Wings is often counterintuitive and presents challenges not seen in standard layouts. In particular, instability observed on detailed aircraft models but never thoroughly investigated, is here studied with the aid of a theoretical/computational framework. Snap-type of instabilities are shown for both pure structural and aeroelastic cases. The concept of snap-divergence is introduced to clearly identify the true aeroelastic instability, as opposed to the usual aeroelastic divergence evaluated through eigenvalue approach. Multi-stable regions and isola-type of bifurcations are possible characterizations of the nonlinear response of Joined Wings, and may lead to branch-jumping phenomena well below nominal critical load condition. Within this picture, sensitivity to (unavoidable) manufacturing defects could have potential catastrophic effects. The phenomena studied in this work suggest that the design process for Joined Wings needs to be revisited and should focus, when instability is concerned, on nonlinear post-critical analysis since linear methods may provide wrong trend indications and also hide potentially catastrophical situations. Dynamic aeroelastic analyses are also performed. Flutter occurrence is critically analyzed with frequency and time-domain capabilities. Sensitivity to different-fidelity aeroelastic modeling (fluid-structure interface algorithm, aerodynamic solvers) is assessed showing that, for some configurations, wake modeling (rigid versus free) has a strong impact on the results. Post-flutter regimes are also explored. Limit cycle oscillations are observed, followed, in some cases, by flip bifurcations (period doubling) and loss of periodicity of the solution. Aeroelastic analyses are then carried out on a

  6. Results of experimental investigations to determine external tank protuberance loads using a 0.03-scale model of the Space Shuttle launch configuration (model 47-OTS) in the NASA/ARC unitary plan wind tunnel, volume 1

    NASA Technical Reports Server (NTRS)

    Houlihan, S. R.

    1992-01-01

    Data were obtained on a 3-percent model of the Space Shuttle launch vehicle in the NASA/Ames Research Center 11x11-foot and 9x7-foot Unitary Plan Wind Tunnels. This test series has been identified as IA190A/B and was conducted from 7 Feb. 1980 to 19 Feb. 1980 (IA190A) and from 17 March 1980 to 19 March 1980 and from 8 May 1980 to 30 May 1980 (IA190B). The primary test objective was to obtain structural loads on the following external tank protuberances: (1) LO2 feedline, (2) GO2 pressure line, (3) LO2 antigeyser line, (4) GH2 pressure line, (5) LH2 tank cable tray, (6) LO2 tank cable tray, (7) Bipod, (8) ET/SRB cable tray, and (9) Crossbeam/Orbiter cable tray. To fulfill these objectives the following steps were taken: (1) Eight 3-component balances were used to measure forces on various sections of 1 thru 6 above. (2) 315 pressure orifices were distributed over all 9 above items. The LO2 feedline was instrumented with 96 pressure taps and was rotated to four positions to yield 384 pressure measurements. The LO2 antigeyser line was instrumented with 64 pressure taps and was rotated to two positions to yield 128 pressure measurements. (3) Three Chrysler miniature flow direction probes were mounted on a traversing mechanism on the tank upper surface centerline to obtain flow field data between the forward and aft attach structures. (4) Schlieren photographs and ultraviolet flow photographs were taken at all test conditions. Data from each of the four test phases are presented.

  7. Results of Experimental Investigations to Determine External Tank Protuberance Loads Using a 0.03-Scale Model of the Space Shuttle Launch Configuration (Model 47-OTS) in the NASA/ARC Unitary Plan Wind Tunnel, Volume 2

    NASA Technical Reports Server (NTRS)

    Houlihan, S. R.

    1992-01-01

    Data were obtained on a 3-percent model of the Space Shuttle launch vehicle in the NASA/Ames Research Center 11x11-foot and 9x7-foot Unitary Plan Wind Tunnels. This test series has been identified as IA19OA/B and was conducted from 7 Feb. 1980 to 19 Feb. 1980 (IA19OA) and from 17 March 1980 to 19 March 1980 and from 8 May 1980 to 30 May 1980 (IA19OB). The primary test objective was to obtain structural loads on the following external tank protuberances: (1) LO2 feedline; (2) GO2 pressure line; (3) LO2 antigeyser line; (4) GH2 pressure line; (5) LH2 tank cable tray; (6) LO2 tank cable tray; (7) Bipod; (8) ET/SRB cable tray; and (9) Crossbeam/Orbiter cable tray. To fulfill these objectives the following steps were taken: Eight 3-component balances were used to measure forces on various sections of 1 thru 6 above; 315 pressure orifices were distributed over all 9 above items. The LO2 feedline was instrumented with 96 pressure taps and was rotated to four positions to yield 384 pressure measurements. The LO2 antigeyser line was instrumented with 64 pressure taps and was rotated to two positions to yield 128 pressure measurements; Three Chrysler miniature flow direction probes were mounted on a traversing mechanism on the tank upper surface centerline to obtain flow field data between the forward and aft attach structures; and Schlieren photographs and ultraviolet flow photographs were taken at all test conditions. Data from each of the four test phases are presented.

  8. Minimum induced drag configurations with jet interaction

    NASA Technical Reports Server (NTRS)

    Pao, J. L.; Lan, C. E.

    1978-01-01

    A theoretical method is presented for determining the optimum camber shape and twist distribution for the minimum induced drag in the wing-alone case without prescribing the span loading shape. The same method was applied to find the corresponding minimum induced drag configuration with the upper-surface-blowing jet. Lan's quasi-vortex-lattice method and his wing-jet interaction theory was used. Comparison of the predicted results with another theoretical method shows good agreement for configurations without the flowing jet. More applicable experimental data with blowing jets are needed to establish the accuracy of the theory.

  9. Snowflake divertor configuration studies for NSTX-Upgrade

    SciTech Connect

    Soukhanovskii, V A

    2011-11-12

    Snowflake divertor experiments in NSTX provide basis for PMI development toward NSTX-Upgrade. Snowflake configuration formation was followed by radiative detachment. Significant reduction of steady-state divertor heat flux observed in snowflake divertor. Impulsive heat loads due to Type I ELMs are partially mitigated in snowflake divertor. Magnetic control of snowflake divertor configuration is being developed. Plasma material interface development is critical for NSTX-U success. Four divertor coils should enable flexibility in boundary shaping and control in NSTX-U. Snowflake divertor experiments in NSTX provide good basis for PMI development in NSTX-Upgrade. FY 2009-2010 snowflake divertor experiments in NSTX: (1) Helped understand control of magnetic properties; (2) Core H-mode confinement unchanged; (3) Core and edge carbon concentration reduced; and (4) Divertor heat flux significantly reduced - (a) Steady-state reduction due to geometry and radiative detachment, (b) Encouraging results for transient heat flux handling, (c) Combined with impurity-seeded radiative divertor. Outlook for snowflake divertor in NSTX-Upgrade: (1) 2D fluid modeling of snowflake divertor properties scaling - (a) Edge and divertor transport, radiation, detachment threshold, (b) Compatibility with cryo-pump and lithium conditioning; (2) Magnetic control development; and (3) PFC development - PFC alignment and PFC material choice.

  10. Low speed wind tunnel test of ground proximity and deck edge effects on a lift cruise fan V/STOL configuration, volume 1

    NASA Technical Reports Server (NTRS)

    Stewart, V. R.

    1979-01-01

    The characteristics were determined of a lift cruise fan V/STOL multi-mission configuration in the near proximity to the edge of a small flat surface representation of a ship deck. Tests were conducted at both static and forward speed test conditions. The model (0.12 scale) tested was a four fan configuration with modifications to represent a three fan configuration. Analysis of data showed that the deck edge effects were in general less critical in terms of differences from free air than a full deck (in ground effect) configuration. The one exception to this was when the aft edge of the deck was located under the center of gravity. This condition, representative of an approach from the rear, showed a significant lift loss. Induced moments were generally small compared to the single axis control power requirements, but will likely add to the pilot work load.

  11. Software Configuration Management Guidebook

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The growth in cost and importance of software to NASA has caused NASA to address the improvement of software development across the agency. One of the products of this program is a series of guidebooks that define a NASA concept of the assurance processes which are used in software development. The Software Assurance Guidebook, SMAP-GB-A201, issued in September, 1989, provides an overall picture of the concepts and practices of NASA in software assurance. Lower level guidebooks focus on specific activities that fall within the software assurance discipline, and provide more detailed information for the manager and/or practitioner. This is the Software Configuration Management Guidebook which describes software configuration management in a way that is compatible with practices in industry and at NASA Centers. Software configuration management is a key software development process, and is essential for doing software assurance.

  12. Oxygen configurations in silica

    SciTech Connect

    Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

    2000-07-15

    We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O{sub 2} bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society.

  13. DAQMAN - A flexible configurable data acquisition system

    SciTech Connect

    Sivertz, Michael; Larry Hoff, Seth Nemesure

    2012-08-01

    DAQMAN is a flexible configurable interface that allows the user to build and operate a VME-based data acquisition system on a Linux workstation. It consists of two parts: a Java-based Graphical User Interface to configure the system, and a C-based utility that reads out the data and creates the output ASCII data file, with two levels of diagnostic tools. The data acquisition system requires a CAEN CONET-VME Bridge to communicate between the hardware in the VME crate and the Linux workstation. Data acquisition modules, such as ADCs, TDC, Scalers, can be loaded into the system, or removed easily. The GUI allows users to activate modules, and channels within modules by clicking on icons. Running configurations are stored; data are collected and can be viewed either as raw numbers, or by charts and histograms that update as the data are accumulated. Data files are written to disk in ASCII format, with a date and time stamp.

  14. Sonic boom configuration minimization

    NASA Technical Reports Server (NTRS)

    Sohn, Robert A.

    1992-01-01

    The topics covered include the following: the sonic boom 'big picture'; current low boom technology; Mach number impact on gross weight; equal loudness equivalent areas; performance and sizing results; potential configuration modifications; equivalent area matching; and impact of nose bluntness on aerodynamic characteristics.

  15. Space Station Final Configuration

    NASA Technical Reports Server (NTRS)

    1994-01-01

    An artist's conception of what the final configuration of the International Space Station (ISS) will look like when it is fully built and deployed. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide an unprecedented undertaking in scientific, technological, and international experimentation.

  16. Inclusive Services Innovation Configuration

    ERIC Educational Resources Information Center

    Holdheide, Lynn R.; Reschly, Daniel J.

    2011-01-01

    Teacher preparation to deliver inclusive services to students with disabilities is increasingly important because of changes in law and policy emphasizing student access to, and achievement in, the general education curriculum. This innovation configuration identifies the components of inclusive services that should be incorporated in teacher…

  17. Relatedness with different interaction configurations.

    PubMed

    Taylor, Peter D; Grafen, A

    2010-02-01

    In an inclusive fitness model of social behaviour, a key concept is that of the relatedness between two interactants. This is typically calculated with reference to a "focal" actor taken to be representative of all actors, but when there are different interaction configurations, relatedness must be constructed as an average over all such configurations. We provide an example of such a calculation in an island model with local reproduction but global mortality, leading to variable island size and hence variable numbers of individual interactions. We find that the analysis of this example significantly sharpens our understanding of relatedness. As an application, we obtain a version of Hamilton's rule for a tag-based model of altruism in a randomly mixed population. For large populations, the selective advantage of altruism is enhanced by low (but not too low) tag mutation rates and large numbers of tags. For moderate population sizes and moderate numbers of tags, we find a window of tag mutation rates with critical benefit/cost ratios of between 1 and 3. PMID:19833134

  18. Analyzing Static Loading of Complex Structures

    NASA Technical Reports Server (NTRS)

    Gallear, D. C.

    1986-01-01

    Critical loading conditions determined from analysis of each structural element. Automated Thrust Structures Loads and Stresses (ATLAS) system is series of programs developed to analyze elements of complex structure under static-loading conditions. ATLAS calculates internal loads, beam-bending loads, column- and web-buckling loads, beam and panel stresses, and beam-corner stresses. Programs written in FORTRAN IV and Assembler for batch execution.

  19. Some aerodynamic characteristics of the scissor wing configuration

    NASA Technical Reports Server (NTRS)

    Selberg, Bruce P.; Rokhsaz, Kamran; Housh, Clinton S.

    1989-01-01

    A scissor wing configuration, consisting of four adjustable wing surfaces, is compared with a comparable fixed wing baseline configuration. Wave drag, induced drag, viscous drag, thrust required, and gust loading are calculated for both configurations. The scissor wing is shown to have lower zero lift wave drag and higher total lift to drag ratios than the baseline. It is demonstrated that the scissor configurations' sweep can be programmed to keep the static margin fixed. Thrust required for both the fixed static margin case and a constant sweep angle case are presented with the scissor configuration requiring lower thrust levels. The gust loading ratio of the scissor wing to the baseline is also shown to be significantly less than 1.0 for sweep angles greater than 20 degrees.

  20. Critical Joints in Large Composite Primary Aircraft Structures. Volume 3: Ancillary Test Results

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.; Sagui, R. L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints for composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of a comprehensive ancillary test program are summarized, consisting of single-bolt composite joint specimens tested in a variety of configurations. These tests were conducted to characterize the strength and load deflection properties that are required for multirow joint analysis. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.005 and 0.01 inch thick unidirectional tape. Tests were conducted in single and double shear for loaded and unloaded hole configurations under both tensile and compressive loading. Two different layup patterns were examined. All tests were conducted at room temperature. In addition, the results of NASA Standard Toughness Test (NASA RP 1092) are reported, which were conducted for several material systems.

  1. Configurations of the amphiphilic molecules in micelles

    SciTech Connect

    Dill, K.A.

    1982-04-29

    Several theoretic models aim to account for the properties of micelles in terms of the configurations of the constituent amphiphilic chain molecules. Recent /sup 13/C NMR measurement of one property of the configuration distribution of the the hydrocarbon chain segments allows critical evaluation of these theories. It is concluded that the interphase and singly-bent chain theories, which fully account for chain continuity and for intermolecular constraints imposed by hydrophobic and steric forces, give a more satisfactory description of micellar molecular organization than models in which chains are ordered and radially aligned, or in which they have the complete disorder characteristic of an amorphous hydrocarbon liquid.

  2. Suspended Load

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The suspended load of rivers and streams consists of the sediments that are kept in the water column by the upward components of the flow velocity. Suspended load may be divided into cohesive and non-cohesive loads which are primarily discriminated by sediment particle size. Non-cohesive sediment ...

  3. Versatile composite amplifier configuration

    NASA Astrophysics Data System (ADS)

    Gift, Stephan J. G.; Maundy, Brent

    2015-06-01

    This paper describes a versatile composite amplifier in which a current feedback amplifier (CFA) drives an operational amplifier (OPA). In the conventional OPA-CFA composite amplifier, an OPA drives a CFA resulting in a composite structure that combines the DC input stability of the OPA and the high speed capability of the CFA. The proposed composite configuration combines different features of the CFA and OPA, specifically the constant bandwidth property of the CFA and the high power and high current output capacity of the OPA. The new circuit is easily implemented in the standard inverting and non-inverting configurations using commercially available devices, and the accuracy and constant bandwidth features were experimentally verified. Local feedback around the associated CFA ensures that the proposed composite amplifier possesses a higher level of bandwidth constancy than a single CFA.

  4. Dynamic Airspace Configuration

    NASA Technical Reports Server (NTRS)

    Bloem, Michael J.

    2014-01-01

    In air traffic management systems, airspace is partitioned into regions in part to distribute the tasks associated with managing air traffic among different systems and people. These regions, as well as the systems and people allocated to each, are changed dynamically so that air traffic can be safely and efficiently managed. It is expected that new air traffic control systems will enable greater flexibility in how airspace is partitioned and how resources are allocated to airspace regions. In this talk, I will begin by providing an overview of some previous work and open questions in Dynamic Airspace Configuration research, which is concerned with how to partition airspace and assign resources to regions of airspace. For example, I will introduce airspace partitioning algorithms based on clustering, integer programming optimization, and computational geometry. I will conclude by discussing the development of a tablet-based tool that is intended to help air traffic controller supervisors configure airspace and controllers in current operations.

  5. Modular small hydro configuration

    NASA Astrophysics Data System (ADS)

    1981-09-01

    Smaller sites (those under 750 kilowatts) which previously were not attractive to develop using equipment intended for application at larger scale sites, were the focal point in the conception of a system which utilizes standard industrial components which are generally available within short procurement times. Such components were integrated into a development scheme for sites having 20 feet to 150 feet of head. The modular small hydro configuration maximizes the use of available components and minimizes modification of existing civil works. A key aspect of the development concept is the use of a vertical turbine multistage pump, used in the reverse mode as a hydraulic turbine. The configuration allows for automated operation and control of the hydroelectric facilities with sufficient flexibility for inclusion of potential hydroelectric sites into dispersed storage and generation (DSG) utility grid systems.

  6. Weighted Configuration Model

    NASA Astrophysics Data System (ADS)

    Serrano, M. Ángeles; Boguñá, Marián

    2005-06-01

    The configuration model is one of the most successful models for generating uncorrelated random networks. We analyze its behavior when the expected degree sequence follows a power law with exponent smaller than two. In this situation, the resulting network can be viewed as a weighted network with non trivial correlations between strength and degree. Our results are tested against large scale numerical simulations, finding excellent agreement.

  7. Fuel cell system configurations

    DOEpatents

    Kothmann, Richard E.; Cyphers, Joseph A.

    1981-01-01

    Fuel cell stack configurations having elongated polygonal cross-sectional shapes and gaskets at the peripheral faces to which flow manifolds are sealingly affixed. Process channels convey a fuel and an oxidant through longer channels, and a cooling fluid is conveyed through relatively shorter cooling passages. The polygonal structure preferably includes at least two right angles, and the faces of the stack are arranged in opposite parallel pairs.

  8. The Configuration Interaction Method

    NASA Astrophysics Data System (ADS)

    Sherrill, C. David; Schaefer, Henry F., III

    Highly correlated configuration interaction (CI) wavefunctions going beyond the simple singles and doubles (CISD) model space can provide very reliable potential energy surfaces, describe electronic excited states, and yield benchmark energies and molecular properties for use in calibrating more approximate methods. Unfortunately, such wavefunctions are also notoriously difficult to evaluate due to their extreme computational demands. The dimension of a full CI procedure, which represents the exact solution of the electronic Schrödinger equation for a fixed one-particle basis set, grows factorially with the number of electrons and basis functions. For very large configuration spaces, the number of CI coupling coefficients becomes prohibitively large to store on disk; these coefficients must be evaluated as needed in a so-called direct CI procedure. Work done by several groups since 1980 has focused on using Slater determinants rather than spin (S2) eigenfunctions because coupling coefficients are easier to compute with the former. We review the fundamentals of the configuration interaction method and discuss various determinant-based CI algorithms. Additionally, we consider some applications of highly correlated CI methods.

  9. Analyzing Visibility Configurations.

    PubMed

    Dachsbacher, C

    2011-04-01

    Many algorithms, such as level of detail rendering and occlusion culling methods, make decisions based on the degree of visibility of an object, but do not analyze the distribution, or structure, of the visible and occluded regions across surfaces. We present an efficient method to classify different visibility configurations and show how this can be used on top of existing methods based on visibility determination. We adapt co-occurrence matrices for visibility analysis and generalize them to operate on clusters of triangular surfaces instead of pixels. We employ machine learning techniques to reliably classify the thus extracted feature vectors. Our method allows perceptually motivated level of detail methods for real-time rendering applications by detecting configurations with expected visual masking. We exemplify the versatility of our method with an analysis of area light visibility configurations in ray tracing and an area-to-area visibility analysis suitable for hierarchical radiosity refinement. Initial results demonstrate the robustness, simplicity, and performance of our method in synthetic scenes, as well as real applications. PMID:20498504

  10. Criticality safety analysis on fissile materials in Fukushima reactor cores

    SciTech Connect

    Liu, Xudong; Lemaitre-Xavier, E.; Ahn, Joonhong; Hirano, Fumio

    2013-07-01

    The present study focuses on the criticality analysis for geological disposal of damaged fuels from Fukushima reactor cores. Starting from the basic understanding of behaviors of plutonium and uranium, a scenario sequence for criticality event is considered. Due to the different mobility of plutonium and uranium in geological formations, the criticality safety is considered in two parts: (1) near-field plutonium system and (2) far-field low enriched uranium (LEU) system. For the near-field plutonium system, a mathematical analysis for pure-solute transport was given, assuming a particular buffer material and waste form configuration. With the transport and decay of plutonium accounted, the critical mass of plutonium was compared with the initial load of a single canister. Our calculation leads us to the conclusion that our system with the initial loading being the average mass of plutonium in an assembly just before the accident is very unlikely to become critical over time. For the far-field LEU system, due to the uncertainties in the geological and geochemical conditions, calculations were made in a parametric space that covers the variation of material compositions and different geometries. Results show that the LEU system could not remain sub-critical within the entire parameter space assumed, although in the iron-rich rock, the neutron multiplicity is significantly reduced.

  11. 44-BWR WASTE PACKAGE LOADING CURVE EVALUATION

    SciTech Connect

    J.M. Scaglione

    2004-08-25

    The objective of this calculation is to evaluate the required minimum burnup as a function of initial boiling water reactor (BWR) assembly enrichment that would permit loading of spent nuclear fuel into the 44 BWR waste package configuration as provided in Attachment IV. This calculation is an application of the methodology presented in ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003). The scope of this calculation covers a range of enrichments from 0 through 5.0 weight percent (wt%) U-235, and a burnup range of 0 through 40 GWd/MTU. This activity supports the validation of the use of burnup credit for commercial spent nuclear fuel applications. The intended use of these results will be in establishing BWR waste package configuration loading specifications. Limitations of this evaluation are as follows: (1) The results are based on burnup credit for actinides and selected fission products as proposed in YMP (2003, Table 3-1) and referred to as the ''Principal Isotopes''. Any change to the isotope listing will have a direct impact on the results of this report. (2) The results of 100 percent of the current BWR projected waste stream being able to be disposed of in the 44-BWR waste package with Ni-Gd Alloy absorber plates is contingent upon the referenced waste stream being sufficiently similar to the waste stream received for disposal. (3) The results are based on 1.5 wt% Gd in the Ni-Gd Alloy material and having no tuff inside the waste package. If the Gd loading is reduced or a process to introduce tuff inside the waste package is defined, then this report would need to be reevaluated based on the alternative materials.

  12. Load cell verification of the uprated high pressure oxygen turbopump for the Space Shuttle Main Engine

    NASA Technical Reports Server (NTRS)

    Beatty, R. F.; Hine, M. J.

    1986-01-01

    The high pressure turbomachinery of the Space Shuttle Main Engine has the highest power-to-weight ratio of any operational machine known. Subsynchronous rotor whirl of the high pressure oxygen turbopump occurred in development testing at full-power level (109 percent thrust). The means by which the turbopump was successfully uprated is presented herein. The subsynchronous motion was determined to be driven by impeller destabilizing forces in combination with low net damping and bearing degradation. The degradation resulted from ball wear due primarily to an excessive loading condition of operating too near the lightly damped rotor second critical speed while under a large static load and, secondarily, from reverse bearing loading or loss of internal clearance and coolant during simulated flight conditions. The rotor response was reduced by stiffening the shaft and supports, optimizing the stiffness and damping of annular seals, and increasing the bearing deadband. The uprated oxygen turbopump configuration was verified by converting the pump and bearing support into a load cell for the purpose of systematically quantifying the load reduction benefits relative to baseline turbopumps. The damped second critical speed margin and the load sharing have been substantially improved which has resulted in reduced bearing loads for improved service life of the machine at full-power level.

  13. Multiplexer/Demultiplexer Loading Tool (MDMLT)

    NASA Technical Reports Server (NTRS)

    Brewer, Lenox Allen; Hale, Elizabeth; Martella, Robert; Gyorfi, Ryan

    2012-01-01

    The purpose of the MDMLT is to improve the reliability and speed of loading multiplexers/demultiplexers (MDMs) in the Software Development and Integration Laboratory (SDIL) by automating the configuration management (CM) of the loads in the MDMs, automating the loading procedure, and providing the capability to load multiple or all MDMs concurrently. This loading may be accomplished in parallel, or single MDMs (remote). The MDMLT is a Web-based tool that is capable of loading the entire International Space Station (ISS) MDM configuration in parallel. It is able to load Flight Equivalent Units (FEUs), enhanced, standard, and prototype MDMs as well as both EEPROM (Electrically Erasable Programmable Read-Only Memory) and SSMMU (Solid State Mass Memory Unit) (MASS Memory). This software has extensive configuration management to track loading history, and the performance improvement means of loading the entire ISS MDM configuration of 49 MDMs in approximately 30 minutes, as opposed to 36 hours, which is what it took previously utilizing the flight method of S-Band uplink. The laptop version recently added to the MDMLT suite allows remote lab loading with the CM of information entered into a common database when it is reconnected to the network. This allows the program to reconfigure the test rigs quickly between shifts, allowing the lab to support a variety of onboard configurations during a single day, based on upcoming or current missions. The MDMLT Computer Software Configuration Item (CSCI) supports a Web-based command and control interface to the user. An interface to the SDIL File Transfer Protocol (FTP) server is supported to import Integrated Flight Loads (IFLs) and Internal Product Release Notes (IPRNs) into the database. An interface to the Monitor and Control System (MCS) is supported to control the power state, and to enable or disable the debug port of the MDMs to be loaded. Two direct interfaces to the MDM are supported: a serial interface (debug port) to

  14. The emergence of load-oriented sterilization.

    PubMed

    Kolstad, R A

    1994-01-01

    Achieving maximum equipment sterilization is critical. Factors that contribute to sterilization efficiency are covered, including sterilization accuracy level, chamber loading and biological indicators. PMID:8031354

  15. GSC configuration management plan

    NASA Technical Reports Server (NTRS)

    Withers, B. Edward

    1990-01-01

    The tools and methods used for the configuration management of the artifacts (including software and documentation) associated with the Guidance and Control Software (GCS) project are described. The GCS project is part of a software error studies research program. Three implementations of GCS are being produced in order to study the fundamental characteristics of the software failure process. The Code Management System (CMS) is used to track and retrieve versions of the documentation and software. Application of the CMS for this project is described and the numbering scheme is delineated for the versions of the project artifacts.

  16. System Measures Loads In Bolts

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.

    1994-01-01

    Improved technique for ultrasonic nondestructive measurement of loads in bolts involves use of pulsed phase-locked loop interferometer. Provides for correction of errors and for automatic readout of loads in bolts. Actual bolt load measured, using transducers rebonded after bolts tightened. Calibration block and thermometer added. Technique applicable to critical fasteners in aerospace applications, nuclear reactors, petroleum and other chemical processing plants, steel bridges, and other structures.

  17. Configurational Entropy Revisited

    NASA Astrophysics Data System (ADS)

    Lambert, Frank L.

    2007-09-01

    Entropy change is categorized in some prominent general chemistry textbooks as being either positional (configurational) or thermal. In those texts, the accompanying emphasis on the dispersal of matter—independent of energy considerations and thus in discord with kinetic molecular theory—is most troubling. This article shows that the variants of entropy can be treated from a unified viewpoint and argues that to decrease students' confusion about the nature of entropy change these variants of entropy should be merged. Molecular energy dispersal in space is implicit but unfortunately tacit in the cell models of statistical mechanics that develop the configurational entropy change in gas expansion, fluids mixing, or the addition of a non-volatile solute to a solvent. Two factors are necessary for entropy change in chemistry. An increase in thermodynamic entropy is enabled in a process by the motional energy of molecules (that, in chemical reactions, can arise from the energy released from a bond energy change). However, entropy increase is only actualized if the process results in a larger number of arrangements for the system's energy, that is, a final state that involves the most probable distribution for that energy under the new constraints. Positional entropy should be eliminated from general chemistry instruction and, especially benefiting "concrete minded" students, it should be replaced by emphasis on the motional energy of molecules as enabling entropy change.

  18. Ductile-to-brittle transition characterization using surface crack specimens loaded in combined tension and bending

    SciTech Connect

    Joyce, J.A.; Link, R.E.

    1997-12-31

    Surface cracked tension specimens of ASTM A515, Grade B steel plate were tested to failure in the ductile-to-brittle transition region. Two different specimen configurations were used: one configuration was loaded in tension except for the natural bending resulting from the presence of the surface crack, the second configuration had an offset test section and was pin-loaded to provide a strong bending component in addition to the tension load. For each configuration, at least seven repeat tests were conducted at each of two temperatures. All specimens failed by cleavage and the critical J-integral, J{sub c}, was obtained using three-dimensional finite element analysis of the specimen. The FEM analysis was validated by comparison with experimental strain gage and displacement measurements taken during the tests. The results were compared with previous fracture toughness measurements on the same plate using 2T SE(B) specimens and surface cracked bend SC(B) specimens. The present results exhibited the expected elevation in fracture toughness and downward shift in the transition temperature compared to the highly constrained, deeply cracked SE(B) specimens. The master curve approach was used to characterize the transition curves for each specimen geometry and the shift in the transition temperature was characterized by the associated reference temperature.

  19. SIM Configuration Evolution

    NASA Technical Reports Server (NTRS)

    Aaron, Kim M.

    2000-01-01

    The Space Interferometry Mission (SIM) is a space-based 10 m baseline Michelson interferometer. Planned for launch in 2005 aboard a Delta III launch vehicle, or equivalent, its primary objective is to measure the positions of stars and other celestial objects with an unprecedented accuracy of 4 micro arc seconds. With such an instrument, tremendous advancement can be expected in our understanding of stellar and galactic dynamics. Using triangulation from opposite sides of the orbit around the sun (i.e. by using parallax) one can measure the distance to any observable object in our galaxy. By directly measuring the orbital wobble of nearby stars, the mass and orbit of planets can be determined over a wide range of parameters. The distribution of velocity within nearby galaxies will be measurable. Observations of these and other objects will improve the calibration of distance estimators by more than an order of magnitude. This will permit a much better determination of the Hubble Constant as well as improving our overall understanding of the evolution of the universe. SIM has undergone several transformations, especially over the past year and a half since the start of Phase A. During this phase of a project, it is desirable to perform system-level trade studies, so the substantial evolution of the design that has occurred is quite appropriate. Part of the trade-off process has addressed two major underlying architectures: SIM Classic; and Son of SIM. The difference between these two architectures is related to the overall arrangement of the optical elements and the associated metrology system. Several different configurations have been developed for each architecture. Each configuration is the result of design choices that are influenced by many competing considerations. Some of the more important aspects will be discussed. The Space Interferometry Mission has some extremely challenging goals: millikelvin thermal stability, nanometer stabilization of optics

  20. Ames Optimized TCA Configuration

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Reuther, James J.; Hicks, Raymond M.

    1999-01-01

    Configuration design at Ames was carried out with the SYN87-SB (single block) Euler code using a 193 x 49 x 65 C-H grid. The Euler solver is coupled to the constrained (NPSOL) and the unconstrained (QNMDIF) optimization packages. Since the single block grid is able to model only wing-body configurations, the nacelle/diverter effects were included in the optimization process by SYN87's option to superimpose the nacelle/diverter interference pressures on the wing. These interference pressures were calculated using the AIRPLANE code. AIRPLANE is an Euler solver that uses a unstructured tetrahedral mesh and is capable of computations about arbitrary complete configurations. In addition, the buoyancy effects of the nacelle/diverters were also included in the design process by imposing the pressure field obtained during the design process onto the triangulated surfaces of the nacelle/diverter mesh generated by AIRPLANE. The interference pressures and nacelle buoyancy effects are added to the final forces after each flow field calculation. Full details of the (recently enhanced) ghost nacelle capability are given in a related talk. The pseudo nacelle corrections were greatly improved during this design cycle. During the Ref H and Cycle 1 design activities, the nacelles were only translated and pitched. In the cycle 2 design effort the nacelles can translate vertically, and pitch to accommodate the changes in the lower surface geometry. The diverter heights (between their leading and trailing edges) were modified during design as the shape of the lower wing changed, with the drag of the diverter changing accordingly. Both adjoint and finite difference gradients were used during optimization. The adjoint-based gradients were found to give good direction in the design space for configurations near the starting point, but as the design approached a minimum, the finite difference gradients were found to be more accurate. Use of finite difference gradients was limited by the

  1. Load cell having strain gauges of arbitrary location

    DOEpatents

    Spletzer, Barry

    2007-03-13

    A load cell utilizes a plurality of strain gauges mounted upon the load cell body such that there are six independent load-strain relations. Load is determined by applying the inverse of a load-strain sensitivity matrix to a measured strain vector. The sensitivity matrix is determined by performing a multivariate regression technique on a set of known loads correlated to the resulting strains. Temperature compensation is achieved by configuring the strain gauges as co-located orthogonal pairs.

  2. An automated approach to magnetic divertor configuration design

    NASA Astrophysics Data System (ADS)

    Blommaert, M.; Dekeyser, W.; Baelmans, M.; Gauger, N. R.; Reiter, D.

    2015-01-01

    Automated methods based on optimization can greatly assist computational engineering design in many areas. In this paper an optimization approach to the magnetic design of a nuclear fusion reactor divertor is proposed and applied to a tokamak edge magnetic configuration in a first feasibility study. The approach is based on reduced models for magnetic field and plasma edge, which are integrated with a grid generator into one sensitivity code. The design objective chosen here for demonstrative purposes is to spread the divertor target heat load as much as possible over the entire target area. Constraints on the separatrix position are introduced to eliminate physically irrelevant magnetic field configurations during the optimization cycle. A gradient projection method is used to ensure stable cost function evaluations during optimization. The concept is applied to a configuration with typical Joint European Torus (JET) parameters and it automatically provides plausible configurations with reduced heat load.

  3. Power converter connection configuration

    DOEpatents

    Beihoff, Bruce C.; Kehl, Dennis L.; Gettelfinger, Lee A.; Kaishian, Steven C.; Phillips, Mark G.; Radosevich, Lawrence D.

    2008-11-11

    EMI shielding is provided for power electronics circuits and the like via a direct-mount reference plane support and shielding structure. The thermal support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support. The support forms a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

  4. Configurable Aperture Space Telescope

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Bendek, Eduardo

    2015-01-01

    In December 2014, we were awarded Center Innovation Fund to evaluate an optical and mechanical concept for a novel implementation of a segmented telescope based on modular, interconnected small sats (satlets). The concept is called CAST, a Configurable Aperture Space Telescope. With a current TRL is 2 we will aim to reach TLR 3 in Sept 2015 by demonstrating a 2x2 mirror system to validate our optical model and error budget, provide straw man mechanical architecture and structural damping analyses, and derive future satlet-based observatory performance requirements. CAST provides an alternative access to visible and/or UV wavelength space telescope with 1-meter or larger aperture for NASA SMD Astrophysics and Planetary Science community after the retirement of HST

  5. Software Configurable Multichannel Transceiver

    NASA Technical Reports Server (NTRS)

    Freudinger, Lawrence C.; Cornelius, Harold; Hickling, Ron; Brooks, Walter

    2009-01-01

    Emerging test instrumentation and test scenarios increasingly require network communication to manage complexity. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. A fundamental requirement for a software-definable radio system is independence from carrier frequencies, one of the radio components that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate the viability of a promising chipset that performs conversion of radio frequency (RF) signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit the size of a commodity disk drive, programmable for any frequency band between 1 MHz and 6 GHz.

  6. Inductrack magnet configuration

    DOEpatents

    Post, Richard Freeman

    2003-10-14

    A magnet configuration comprising a pair of Halbach arrays magnetically and structurally connected together are positioned with respect to each other so that a first component of their fields substantially cancels at a first plane between them, and a second component of their fields substantially adds at this first plane. A track of windings is located between the pair of Halbach arrays and a propulsion mechanism is provided for moving the pair of Halbach arrays along the track. When the pair of Halbach arrays move along the track and the track is not located at the first plane, a current is induced in the windings and a restoring force is exerted on the pair of Halbach arrays.

  7. Inductrack magnet configuration

    DOEpatents

    Post, Richard Freeman

    2003-12-16

    A magnet configuration comprising a pair of Halbach arrays magnetically and structurally connected together are positioned with respect to each other so that a first component of their fields substantially cancels at a first plane between them, and a second component of their fields substantially adds at this first plane. A track of windings is located between the pair of Halbach arrays and a propulsion mechanism is provided for moving the pair of Halbach arrays along the track. When the pair of Halbach arrays move along the track and the track is not located at the first plane, a current is induced in the windings and a restoring force is exerted on the pair of Halbach arrays.

  8. Investigation of the Loads on a Conventional Front and Rear Sliding Canopy

    NASA Technical Reports Server (NTRS)

    Dexter, Howard E.; Rickey, Edward A.

    1947-01-01

    As one phase of a comprehensive canopy load investigation, conventional front and rear sliding canopies which are typified by installation on the SB2C-4E airplane, were tested in the Langley full-scale tunnel to determine the pressure distributions and the aerodynamic loads on the canopies. A preliminary analysis of the results of these tests is presented in this report. Plots are presented that show the distribution of pressure at four longitudinal stations through each canopy for a range of conditions selected to determine the effects of varying canopy position, yaw, lift coefficient, and power. The results indicate that the maximum loads, based on the external-internal pressure differential, for the front and rear canopies were obtained with the airplane simulating the high speed flight condition. The highest loading on the front canopy was in the exploding direction for the configuration with the front and rear canopies closed. The highest loads on the rear canopy were in the crushing direction with the front canopy open and the rear canopy closed. For most of the simulated flight conditions, the highest loads on the front canopy, per unit area, were over twice as great as the highest loads on the rear canopy when the comparison was made for the most critical canopy configuration in each case. The external pressure distribution over the front and rear canopies, which were fairly symmetrical to 0 degree angle of yaw, were greatly distorted at other yaw attitudes, particularly for the propeller operating conditions. These distorted pressure distributions resulted in local exploding and crushing loads on both canopies which were often considerably higher than the average canopy loads.

  9. CFD configurations for hydraulic turbine startup

    NASA Astrophysics Data System (ADS)

    Nicolle, J.; Giroux, A. M.; Morissette, J. F.

    2014-03-01

    This paper presents various numerical setups for modelling Francis turbine startups involving moving meshes and variable runner speed in order to help define best practices. During the accelerating phase of the startup, the flow is self-similar between channels, thus making single sector configuration appropriate. Adding the draft tube improves the results by allowing pressure recovery midway during in the startup. At the speed no-load regime, a rotating stall phenomenon occurs and can only be capted with the full runner included in the simulation. Comparison with experimental data, such as runner speed and strain gauge measurements, generally shows good agreement.

  10. Potential flow applications to complex configurations

    NASA Technical Reports Server (NTRS)

    Cenko, A.; Tseng, W.; Madson, M.

    1991-01-01

    Recent advances in CFD methods have enabled the analytic calculation of the carriage loads for stores mounted on complex aircraft. The latest results have demonstrated excellent agreement with test data for the F-15 at M = 0.98. However, in a preliminary design environment, the necessity of generating and validating a Euler grid to fit the aircraft and store arrangement may not be feasible, particularly when effects of configuration changes are considered. For that reason alternative approaches which require less time to arrive at an answer deserve consideration. The paper presents the results of a study to determine if potential flow solutions can give acceptable estimates of store carriage loads at transonic speeds in a timely manner.

  11. Achieving Integrated FEA Model and Loads Management

    NASA Astrophysics Data System (ADS)

    Lauzon, Dominick; Huf, Brian; Hagstrom, Dustin

    2012-07-01

    Recent developments in enterprise level simulation tools now enable CAE engineers and managers to keep up with today’s accelerating rate in the number and complexity of simulation models. All simulation related activities including Finite Element Models (FEM) variants and their respective results datasets can now be captured and managed. This provides valuable model pedigree from the source geometry referenced in the PDM system, spacecraft design and FEM configurations, external loads, simulation results and internal loads down to key results with the final critical design review and test correlation reports. The process presented in this paper demonstrates how simulation data capture and relationships can be achieved. Moreover, process management from conceptual design to spacecraft final proto-flight tests can now be achieved systematically and efficiently while performing and ensuring model quality, all the way from assembly level down to component level. MSC Software’s SimXpert and SimManager, two commercial off-the-shelf software codes, are used to highlight the benefits of this approach. In addition, an automation process that performs model validation per aerospace engineering best practice standards is also presented.

  12. Hubble Space Telescope Configuration

    NASA Technical Reports Server (NTRS)

    1985-01-01

    This image illustrates the overall Hubble Space Telescope (HST) configuration. The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

  13. Finite Element Development of Honeycomb Panel Configurations with Improved Transmission Loss

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Palumbo, Daniel L.; Klos, Jacob; Castle, William D.

    2006-01-01

    The higher stiffness-to-mass ratio of a honeycomb panel compared to a homogeneous panel results in a lower acoustic critical frequency. Above the critical frequency the panel flexural wave speed is acoustically fast and the structure becomes a more efficient radiator with associated lower sound transmission loss. Finite element models of honeycomb sandwich structures are presented featuring areas where the core is removed from the radiating face sheet disrupting the supersonic flexural and shear wave speeds that exist in the baseline honeycomb panel. These modified honeycomb panel structures exhibit improved transmission loss for a pre-defined diffuse field sound excitation. The models were validated by the sound transmission loss of honeycomb panels measured in the Structural Acoustic Loads and Transmission (SALT) facility at the NASA Langley Research Center. A honeycomb core panel configuration is presented exhibiting a transmission loss improvement of 3-11 dB compared to a honeycomb baseline panel over a frequency range from 170 Hz to 1000 Hz. The improved transmission loss panel configuration had a 5.1% increase in mass over the baseline honeycomb panel, and approximately twice the deflection when excited by a static force.

  14. Critical fluid light scattering

    NASA Technical Reports Server (NTRS)

    Gammon, Robert W.

    1988-01-01

    The objective is to measure the decay rates of critical density fluctuations in a simple fluid (xenon) very near its liquid-vapor critical point using laser light scattering and photon correlation spectroscopy. Such experiments were severely limited on Earth by the presence of gravity which causes large density gradients in the sample when the compressibility diverges approaching the critical point. The goal is to measure fluctuation decay rates at least two decades closer to the critical point than is possible on earth, with a resolution of 3 microK. This will require loading the sample to 0.1 percent of the critical density and taking data as close as 100 microK to the critical temperature. The minimum mission time of 100 hours will allow a complete range of temperature points to be covered, limited by the thermal response of the sample. Other technical problems have to be addressed such as multiple scattering and the effect of wetting layers. The experiment entails measurement of the scattering intensity fluctuation decay rate at two angles for each temperature and simultaneously recording the scattering intensities and sample turbidity (from the transmission). The analyzed intensity and turbidity data gives the correlation length at each temperature and locates the critical temperature. The fluctuation decay rate data from these measurements will provide a severe test of the generalized hydrodynamic theories of transport coefficients in the critical regions. When compared to equivalent data from binary liquid critical mixtures they will test the universality of critical dynamics.

  15. Multi-Body Analysis of a Tiltrotor Configuration

    NASA Technical Reports Server (NTRS)

    Ghiringhelli, G. L.; Masarati, P.; Mantegazza, P.; Nixon, M. W.

    1997-01-01

    The paper describes the aeroelastic analysis of a tiltrotor configuration. The 1/5 scale wind tunnel semispan model of the V-22 tiltrotor aircraft is considered. The analysis is performed by means of a multi-body code, based on an original formulation. The differential equilibrium problem is stated in terms of first order differential equations. The equilibrium equations of every rigid body are written, together with the definitions of the momenta. The bodies are connected by kinematic constraints, applied in form of Lagrangian multipliers. Deformable components are mainly modelled by means of beam elements, based on an original finite volume formulation. Multi-disciplinar problems can be solved by adding user-defined differential equations. In the presented analysis the equations related to the control of the swash-plate of the model are considered. Advantages of a multi-body aeroelastic code over existing comprehensive rotorcraft codes include the exact modelling of the kinematics of the hub, the detailed modelling of the flexibility of critical hub components, and the possibility to simulate steady flight conditions as well as wind-up and maneuvers. The simulations described in the paper include: 1) the analysis of the aeroelastic stability, with particular regard to the proprotor/pylon instability that is peculiar to tiltrotors, 2) the determination of the dynamic behavior of the system and of the loads due to typical maneuvers, with particular regard to the conversion from helicopter to airplane mode, and 3) the stress evaluation in critical components, such as the pitch links and the conversion downstop spring.

  16. Effects of partial interlaminar bonding on impact resistance and loaded-hole behavior of graphite/epoxy quasi-isotropic laminates

    NASA Technical Reports Server (NTRS)

    Illg, W.

    1986-01-01

    A partial-bonding interlaminar toughening concept was evaluated for resistance to impact and for behavior of a loaded hole. Perforated Mylar sheets were interleaved between all 24 plies of a graphite/epoxy quasi-isotropic lay-up. Specimens were impacted by aluminum spheres while under tensile or compressive loads. Impact-failure thresholds and residual strengths were obtained. Loaded-hole specimens were tested in three configurations that were critical in bearing, shear, or tension. Partial bonding reduced the tensile and compressive strengths of undamaged specimens by about one-third. For impact, partial bonding did not change the threshold for impact failure under tensile preload. However, under compressive preload, partial bonding caused serious degradation of impact resistance. Partial bonding reduced the maximum load-carrying capacity of all three types of loaded-hole specimens. Overall, partial bonding degraded both impact resistance and bearing strength of holes.

  17. DAQMAN - A flexible configurable data acquisition system

    Energy Science and Technology Software Center (ESTSC)

    2012-08-01

    DAQMAN is a flexible configurable interface that allows the user to build and operate a VME-based data acquisition system on a Linux workstation. It consists of two parts: a Java-based Graphical User Interface to configure the system, and a C-based utility that reads out the data and creates the output ASCII data file, with two levels of diagnostic tools. The data acquisition system requires a CAEN CONET-VME Bridge to communicate between the hardware in themore » VME crate and the Linux workstation. Data acquisition modules, such as ADCs, TDC, Scalers, can be loaded into the system, or removed easily. The GUI allows users to activate modules, and channels within modules by clicking on icons. Running configurations are stored; data are collected and can be viewed either as raw numbers, or by charts and histograms that update as the data are accumulated. Data files are written to disk in ASCII format, with a date and time stamp.« less

  18. Computational topology for configuration spaces of hard disks.

    PubMed

    Carlsson, Gunnar; Gorham, Jackson; Kahle, Matthew; Mason, Jeremy

    2012-01-01

    We explore the topology of configuration spaces of hard disks experimentally and show that several changes in the topology can already be observed with a small number of particles. The results illustrate a theorem of Baryshnikov, Bubenik, and Kahle that critical points correspond to configurations of disks with balanced mechanical stresses and suggest conjectures about the asymptotic topology as the number of disks tends to infinity. PMID:22400561

  19. A novel approach to magnetic divertor configuration design

    NASA Astrophysics Data System (ADS)

    Blommaert, M.; Baelmans, M.; Dekeyser, W.; Gauger, N. R.; Reiter, D.

    2015-08-01

    Divertor exhaust system design and analysis tools are crucial to evolve from experimental fusion reactors towards commercial power plants. In addition to material research and dedicated vessel geometry design, improved magnetic configurations can contribute to sustaining the diverted heat loads. Yet, computational design of the magnetic divertor is a challenging process involving a magnetic equilibrium solver, a plasma edge grid generator and a computationally demanding plasma edge simulation. In this paper, an integrated approach to efficient sensitivity calculations is discussed and applied to a set of slightly reduced divertor models. Sensitivities of target heat load performance to the shaping coil currents are directly evaluated. Using adjoint methods, the cost for a sensitivity evaluation is reduced to about two times the simulation cost of one specific configuration. Further, the use of these sensitivities in an optimal design framework is illustrated by a case with realistic Joint European Torus (JET) configurational parameters.

  20. Analysis on shock attenuation in gap test configuration for characterizing energetic materials

    NASA Astrophysics Data System (ADS)

    Kim, Bohoon; Park, Jungsu; Yoh, Jack J.

    2016-04-01

    A pyrotechnic system consisting of donor/acceptor pair separated by a gap relies on shock attenuation characteristics of the gap material and shock sensitivity of the donor and the acceptor charges. Despite of its common use, a numerical study of such a pyrotechnic train configuration is seldom reported because proper modeling of the full process requires precise capturing of the shock wave attenuation in the gap prior to triggering a full detonation of a high explosive and accurate description of the high strain rate dynamics of the explosively loaded inert confinements. We apply a hybrid particle level-set based multimaterial hydrocode with reactive flow models for pentolite donor and heavily aluminized cyclotrimethylene-trinitramine as the acceptor charge. The complex shock interaction, a critical gap thickness, an acoustic impedance, and go/no-go characteristics of the pyrotechnic system are quantitatively investigated.

  1. Carbohydrate Loading.

    ERIC Educational Resources Information Center

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  2. Space Station reference configuration update

    NASA Technical Reports Server (NTRS)

    Bonner, Tom F., Jr.

    1985-01-01

    The reference configuration of the NASA Space Station as of November 1985 is presented in a series of diagrams, drawings, graphs, and tables. The configurations for components to be contributed by ESA, Canada, and Japan are included. Brief captions are provided, along with answers to questions raised at the conference.

  3. Critical Thinking.

    ERIC Educational Resources Information Center

    Callison, Daniel

    1998-01-01

    Distinguishes between critical and creative thinking and discusses critical-thinking in relation to modern instructional programs and information literacy. Outlines goals in critical-thinking curriculum, critical thinking skills (student disposition, interpretation, analysis, evaluation, inference, presenting argument, and reflection), and…

  4. Radiant-interchange Configuration Factors

    NASA Technical Reports Server (NTRS)

    Hamilton, D C :; Morgan, W R

    1952-01-01

    A study is presented of the geometric configuration factors required for computing radiant heat transfer between opaque surfaces separated by a nonabsorbing medium and various methods of determining the configuration factors are discussed. Configuration-factor solutions available in the literature have been checked and the more complicated equations are presented as families of curves. Cases for point, line, and finite-area sources are worked out over a wide range of geometric proportions. These cases include several new configurations involving rectangles, triangles, and cylinders of finite length which are integrated and tabulated. An analysis is presented, in which configuration factors are employed of the radiant heat transfer to the rotor blades of a typical gas turbine under different conditions of temperature and pressure. (author)

  5. Parametric analysis of ATT configurations.

    NASA Technical Reports Server (NTRS)

    Lange, R. H.

    1972-01-01

    This paper describes the results of a Lockheed parametric analysis of the performance, environmental factors, and economics of an advanced commercial transport envisioned for operation in the post-1985 time period. The design parameters investigated include cruise speeds from Mach 0.85 to Mach 1.0, passenger capacities from 200 to 500, ranges of 2800 to 5500 nautical miles, and noise level criteria. NASA high performance configurations and alternate configurations are operated over domestic and international route structures. Indirect and direct costs and return on investment are determined for approximately 40 candidate aircraft configurations. The candidate configurations are input to an aircraft sizing and performance program which includes a subroutine for noise criteria. Comparisons are made between preferred configurations on the basis of maximum return on investment as a function of payload, range, and design cruise speed.

  6. Ultrasonic measurement and monitoring of loads in bolts used in structural joints

    NASA Astrophysics Data System (ADS)

    Koshti, Ajay M.

    2015-04-01

    The paper is an overview of work by the author in measuring and monitoring loads in bolts using an ultrasonic extensometer. A number of cases of bolted joints are covered. These include, a clamped joint with clearance fit between the bolt and hole, a clamped joint with bolt in an interference fit with the hole, a flanged joint which allows the flange and bolt to bend; and a shear joint in a clevis and tang configuration. These applications were initially developed for measuring and monitoring preload in National Aeronautics and Space Administration (NASA) Space Shuttle Orbiter critical joints but are also applicable for monitoring loads in other critical bolted joints of structures such as transportation bridges and other aerospace structures. The papers cited here explain how to set-up a model to estimate the ultrasonic load factor and accuracy for the ultrasonic preload application in a clamped joint with clearance fit. The ultrasonic preload application for clamped joint with bolt in an interference fit can also be used to measure diametrical interference between the bolt shank and hole, as well as interference pressure on the bolt shank. Results of simulation and experimental data are given to demonstrate use of ultrasonic measurements in a shear joint. A bolt in a flanged joint experiences both tensile and bending loads. This application involves measurement of bending and tensile preload in a bolt. The ultrasonic beam bends due to bending load on the bolt. Results of a numerical technique to compute the trace of ultrasonic ray are presented.

  7. Physics and Engineering Assessmetns of the K-DEMO Magnet Configuration

    SciTech Connect

    Neilson, George H.; Brown, Thomas

    2014-09-01

    Increased attention is being given now to studies of next-step fusion facilities with nuclear missions. Among these, South Korea's K DEMO is unique in its focus on a high toroidal magnetic field, large major radius, steady-state tokamak design for the core of a facility to test fusion nuclear components in Phase I and, after upgrades, produce 500 MW of electricity in a Phase II. Innovative features of the K DEMO magnet set include the use of two toroidal field (TF) coil winding packs with conductor grading and a machine configuration designed for vertical maintenance. The magnet arrangement features large TF coils and widely spaced poloidal field (PF) coils to accommodate removal of in-vessel components as large modules. Physics and engineering assessments of the pre-conceptual K-DEMO magnet configuration are reported, including: 1) design point and operating space assessment, 2) conductor assessment, and 3) structural assessment. It is found that a reference design point at 6.8 m major radius and 7.4 T toroidal field provides sufficient operating margins for the 500 MWe Phase II mission. Analyses of candidate cable-in-conduit conductors provide predictions of critical current degradation, both in the initial load cycle and an additionally with cyclic loading. A first-pass global analysis of the magnet system found minimal out-of-plane deformations of the TF coil, but an overstress condition in the inner leg of the TF coil. However an analysis taking into account elastic-plastic behavior, frictional sliding, and displacement shows that the structure can safely carry the load. Although the design evolution is still at an early stage, these assessments support the design point choices to date and the expectation that a feasible solution for the high-field K DEMO magnet system can be found.

  8. The ASTRO-1 preliminary design review coupled load analysis

    NASA Technical Reports Server (NTRS)

    Mcghee, D. S.

    1984-01-01

    Results of the ASTRO-1 preliminary design review coupled loads analysis are presented. The M6.0Y Generic Shuttle mathematical models were used. Internal accelerations, interface forces, relative displacements, and net e.g., accelerations were recovered for two ASTRO-1 payloads in a tandem configuration. Twenty-seven load cases were computed and summarized. Load exceedences were found and recommendations made.

  9. Thinking Critically about Critical Thinking

    ERIC Educational Resources Information Center

    Mulnix, Jennifer Wilson

    2012-01-01

    As a philosophy professor, one of my central goals is to teach students to think critically. However, one difficulty with determining whether critical thinking can be taught, or even measured, is that there is widespread disagreement over what critical thinking actually is. Here, I reflect on several conceptions of critical thinking, subjecting…

  10. Viscous Design of TCA Configuration

    NASA Technical Reports Server (NTRS)

    Krist, Steven E.; Bauer, Steven X. S.; Campbell, Richard L.

    1999-01-01

    The goal in this effort is to redesign the baseline TCA configuration for improved performance at both supersonic and transonic cruise. Viscous analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between overset grids. Viscous designs are conducted with OVERDISC, a script which couples OVERFLOW with the Constrained Direct Iterative Surface Curvature (CDISC) inverse design method. The successful execution of any computational fluid dynamics (CFD) based aerodynamic design method for complex configurations requires an efficient method for regenerating the computational grids to account for modifications to the configuration shape. The first section of this presentation deals with the automated regridding procedure used to generate overset grids for the fuselage/wing/diverter/nacelle configurations analysed in this effort. The second section outlines the procedures utilized to conduct OVERDISC inverse designs. The third section briefly covers the work conducted by Dick Campbell, in which a dual-point design at Mach 2.4 and 0.9 was attempted using OVERDISC; the initial configuration from which this design effort was started is an early version of the optimized shape for the TCA configuration developed by the Boeing Commercial Airplane Group (BCAG), which eventually evolved into the NCV design. The final section presents results from application of the Natural Flow Wing design philosophy to the TCA configuration.

  11. LOADED WAVEGUIDES

    DOEpatents

    Mullett, L.B.; Loach, B.G.; Adams, G.L.

    1958-06-24

    >Loaded waveguides are described for the propagation of electromagnetic waves with reduced phase velocities. A rectangular waveguide is dimensioned so as to cut-off the simple H/sub 01/ mode at the operating frequency. The waveguide is capacitance loaded, so as to reduce the phase velocity of the transmitted wave, by connecting an electrical conductor between directly opposite points in the major median plane on the narrower pair of waveguide walls. This conductor may take a corrugated shape or be an aperature member, the important factor being that the electrical length of the conductor is greater than one-half wavelength at the operating frequency. Prepared for the Second U.N. International ConferThe importance of nuclear standards is duscussed. A brief review of the international callaboration in this field is given. The proposal is made to let the International Organization for Standardization (ISO) coordinate the efforts from other groups. (W.D.M.)

  12. Device configuration-management system

    SciTech Connect

    Nowell, D.M.

    1981-01-01

    The Fusion Chamber System, a major component of the Magnetic Fusion Test Facility, contains several hundred devices which report status to the Supervisory Control and Diagnostic System for control and monitoring purposes. To manage the large number of diversity of devices represented, a device configuration management system was required and developed. Key components of this software tool include the MFTF Data Base; a configuration editor; and a tree structure defining the relationships between the subsystem devices. This paper will describe how the configuration system easily accomodates recognizing new devices, restructuring existing devices, and modifying device profile information.

  13. Loading operations for spacecraft propulsion subsystems

    NASA Astrophysics Data System (ADS)

    Purohit, G. P.; Nordeng, H. O.; Ellison, J. R.

    1992-07-01

    This paper provides a broad overview of loading operations for pressurized blowdown monopropellant and pressure regulated integral bipropellant propulsion subsystems used in geosynchronous communication satellites. Propellant chemical composition, cleanliness, processing, and handling requirements are addressed. Ground servicing equipment (GSE) and propellant transfer procedures for the various loading configurations are discussed. Effects of helium solubility and helium saturation levels in both GSE carts and propellant tanks are examined. Predicted equilibrium pressures for actual postload tank pressures are compared against extensive loading data on Hughes bipropellant spacecraft. Helium tank pressurization and manifold pressurization practices are described. Propellant loading facility requirements and safety requirements are discussed.

  14. Structural Concepts Study of Non-circular Fuselage Configurations

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, Vivel

    1996-01-01

    A preliminary study of structural concepts for noncircular fuselage configurations is presented. For an unconventional flying-wing type aircraft, in which the fuselage is inside the wing, multiple fuselage bays with non-circular sections need to be considered. In a conventional circular fuselage section, internal pressure is carried efficiently by a thin skin via hoop tension. If the section is non-circular, internal pressure loads also induce large bending stresses. The structure must also withstand additional bending and compression loads from aerodynamic and gravitational forces. Flat and vaulted shell structural configurations for such an unconventional, non-circular pressurized fuselage of a large flying-wing were studied. A deep honeycomb sandwich-shell and a ribbed double-wall shell construction were considered. Combinations of these structural concepts were analyzed using both analytical and simple finite element models of isolated sections for a comparative conceptual study. Weight, stress, and deflection results were compared to identify a suitable configuration for detailed analyses. The flat sandwich-shell concept was found preferable to the vaulted shell concept due to its superior buckling stiffness. Vaulted double-skin ribbed shell configurations were found to be superior due to their weight savings, load diffusion, and fail-safe features. The vaulted double-skin ribbed shell structure concept was also analyzed for an integrated wing-fuselage finite element model. Additional problem areas such as wing-fuselage junction and pressure-bearing spar were identified.

  15. Optimized Minimal Inductance Transmission Line Configuration for Z-Pinch Experiments

    SciTech Connect

    Hurricane, O

    2003-10-16

    Successful dynamic Z-pinch experiments generally require good current delivery to the target load. Power flow losses through highly inductive transmission line configurations reduce the current available to the load. In this Brief Report, a variational calculus technique is used to determine the transmission line configuration that produces the least possible inductance and therefore the best possible current delivery for Z-pinch experiments.

  16. SAMI Automated Plug Plate Configuration

    NASA Astrophysics Data System (ADS)

    Lorente, N. P. F.; Farrell, T.; Goodwin, M.

    2013-10-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) which uses a plug-plate to mount its 13×61-core imaging fibre bundles (hexabundles) in the optical path at the telescope's prime focus. In this paper we describe the process of determining the positions of the plug-plate holes, where plates contain three or more stacked observation configurations. The process, which up until now has involved several separate processes and has required significant manual configuration and checking, is now being automated to increase efficiency and reduce error. This is carried out by means of a thin Java controller layer which drives the configuration cycle. This layer controls the user interface and the C++ algorithm layer where the plate configuration and optimisation is carried out. Additionally, through the Aladin display package, it provides visualisation and facilitates user verification of the resulting plates.

  17. Critical Care

    MedlinePlus

    Critical care helps people with life-threatening injuries and illnesses. It might treat problems such as complications from surgery, ... attention by a team of specially-trained health care providers. Critical care usually takes place in an ...

  18. Space Station reference configuration description

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The data generated by the Space Station Program Skunk Works over a period of 4 months which supports the definition of a Space Station reference configuration is documented. The data were generated to meet these objectives: (1) provide a focal point for the definition and assessment of program requirements; (2) establish a basis for estimating program cost; and (3) define a reference configuration in sufficient detail to allow its inclusion in the definition phase Request for Proposal (RFP).

  19. Context based configuration management system

    NASA Technical Reports Server (NTRS)

    Gawdiak, Yuri O. (Inventor); Gurram, Mohana M. (Inventor); Maluf, David A. (Inventor); Mederos, Luis A. (Inventor)

    2010-01-01

    A computer-based system for configuring and displaying information on changes in, and present status of, a collection of events associated with a project. Classes of icons for decision events, configurations and feedback mechanisms, and time lines (sequential and/or simultaneous) for related events are displayed. Metadata for each icon in each class is displayed by choosing and activating the corresponding icon. Access control (viewing, reading, writing, editing, deleting, etc.) is optionally imposed for metadata and other displayed information.

  20. Dynamic Stability Optimization of Laminated Composite Plates under Combined Boundary Loading

    NASA Astrophysics Data System (ADS)

    Shafei, Erfan; Kabir, Mohammad Zaman

    2011-12-01

    Dynamic stability and design optimization of laminated simply supported plates under planar conservative boundary loads are investigated in current study. Examples can be found in internal connecting elements of spacecraft and aerospace structures subjected to edge axial and shear loads. Designation of such elements is function of layup configuration, plate aspect ratio, loading combinations, and layup thickness. An optimum design aims maximum stability load satisfying a predefined stable vibration frequency. The interaction between compound loading and layup angle parameter affects the order of merging vibration modes and may stabilize the dynamic response. Laminated plates are assumed to be angle-plies symmetric to mid-plane surface. Dynamic equilibrium PDE has been solved using kernel integral transformation for modal frequency values and eigenvalue-based orthogonal functions for critical stability loads. The dictating dynamic stability mode is shown to be controlled by geometric stiffness distributions of composite plates. Solution of presented design optimization problem has been done using analytical approach combined with interior penalty multiplier algorithm. The results are verified by FEA approach and stability zones of original and optimized plates are stated as final data. Presented method can help designers to stabilize the dynamic response of composite plates by selecting an optimized layup orientation and thickness for prescribed design circumstances.

  1. Mapping HIV community viral load: space, power and the government of bodies.

    PubMed

    Gagnon, Marilou; Guta, Adrian

    2012-12-01

    HIV plasma viral load testing has become more than just a clinical tool to monitor treatment response at the individual level. Increasingly, individual HIV plasma viral load testing is being reported to public health agencies and is used to inform epidemiological surveillance and monitor the presence of the virus collectively using techniques to measure 'community viral load'. This article seeks to formulate a critique and propose a novel way of theorizing community viral load. Based on the salient work of Michel Foucault, especially the governmentality literature, this article critically examines the use of community viral load as a new strategy of government. Drawing also on the work of Miller and Rose, this article explores the deployment of 'community' through the re-configuration of space, the problematization of viral concentrations in specific microlocales, and the government (in the Foucauldian sense) of specific bodies which are seen as 'risky', dangerous and therefore, in need of attention. It also examines community viral load as a necessary precondition - forming the 'conditions of possibility' - for the recent shift to high impact prevention tactics that are being scaled up across North America. PMID:23060688

  2. EAST alternative magnetic configurations: modelling and first experiments

    NASA Astrophysics Data System (ADS)

    Calabrò, G.; Xiao, B. J.; Chen, S. L.; Duan, Y. M.; Guo, Y.; Li, J. G.; Liu, L.; Luo, Z. P.; Wang, L.; Xu, J.; Zhang, B.; Albanese, R.; Ambrosino, R.; Crisanti, F.; Pericoli Ridolfini, V.; Villone, F.; Viola, B.; Barbato, L.; De Magistris, M.; De Tommasi, G.; Giovannozzi, E.; Mastrostefano, S.; Minucci, S.; Pironti, A.; Ramogida, G.; Tuccillo, A. A.; Zagórski, R.

    2015-08-01

    Heat and particle loads on the plasma facing components are among the most challenging issues to be solved for a reactor design. Alternative magnetic configurations may enable tokamak operation with a lower peak heat load than a standard single null (SN) divertor. This papers reports on the creation and control of one of such alternatives: a two-null nearby divertor configuration. An important element of this study is that this two-null divertor was produced on a large superconducting tokamak as an experimental advanced superconducting tokamak. A preliminary experiment with the second null forming a configuration with significant distance between the two nulls and a contracting geometry near the target plates was performed in 2014. These configurations have been designed using the FIXFREE code and optimized with CREATE-NL tools and are discussed in the paper. Predictive edge simulations using the TECXY code are also presented by comparing the advanced divertor and SN configuration. Finally, the experimental results of ohmic and low confinement (L-mode) two-null divertor and SN discharges and interpretative two-dimensional edge simulations are discussed. Future experiments will be devoted to varying the distance between the two nulls in high confinement (H-mode) discharges.

  3. Optimal configuration algorithm of a satellite transponder

    NASA Astrophysics Data System (ADS)

    Sukhodoev, M. S.; Savenko, I. I.; Martynov, Y. A.; Savina, N. I.; Asmolovskiy, V. V.

    2016-04-01

    This paper describes the algorithm of determining the optimal transponder configuration of the communication satellite while in service. This method uses a mathematical model of the pay load scheme based on the finite-state machine. The repeater scheme is shown as a weighted oriented graph that is represented as plexus in the program view. This paper considers an algorithm example for application with a typical transparent repeater scheme. In addition, the complexity of the current algorithm has been calculated. The main peculiarity of this algorithm is that it takes into account the functionality and state of devices, reserved equipment and input-output ports ranged in accordance with their priority. All described limitations allow a significant decrease in possible payload commutation variants and enable a satellite operator to make reconfiguration solutions operatively.

  4. Impact of dynamic loads on propulsion integration

    NASA Technical Reports Server (NTRS)

    Seiner, J. M.

    1994-01-01

    Aircraft dynamic loads produced by engine exhaust plumes are examined for a class of military fighter and bomber configurations in model and full scale. The configurations examined are associated with the USAF F-15 and B-1B aircraft, and the US F-18 HARV and ASTOVL programs. The experience gained as a result of these studies is used to formulate a level of understanding concerning this phenomena that could be useful at the preliminary stage of propulsion/airframe design.

  5. Modal Analysis and Correlation of International Space Station Early Configurations

    NASA Technical Reports Server (NTRS)

    Kaouk, Mohamed; Shein, Shya-Ling; Kim, Hyoung M.

    2000-01-01

    This paper will summarize the modal analysis and model refinement results for the International Space Station (ISS) Flight-2A mated configuration. To maintain structural integrity of the ISS, structural loading distributions have been rigorously analyzed through numerical simulation and taken into account during the design of the structure and mission operations. The accuracy of the analysis results is directly affected by the precision of mathematical models and estimated input forces. A mathematical model of an ISS configuration is composed of individual component math models. Each component model is required to be correlated with ground test data.

  6. Drag of the complete configuration aerodynamic considerations, 2

    NASA Technical Reports Server (NTRS)

    Roskam, J.

    1975-01-01

    A number of drag items are related to the performance of a complete aircraft configuration. First, the effect of fuselage camber, wing and nacelle incidence are discussed from a viewpoint of design decision making. Second, the effect of overall cruise drag on the design gross and empty weight of the airplane is discussed. Examples show that cruise drag can have a very important influence on total airplane weight. Third, the effects of usable cruise lift-to-drag ratio and wing loading are shown to be important. Finally several research needs relating to design of the complete configuration are reviewed.

  7. Split torque transmission load sharing

    NASA Technical Reports Server (NTRS)

    Krantz, T. L.; Rashidi, M.; Kish, J. G.

    1992-01-01

    Split torque transmissions are attractive alternatives to conventional planetary designs for helicopter transmissions. The split torque designs can offer lighter weight and fewer parts but have not been used extensively for lack of experience, especially with obtaining proper load sharing. Two split torque designs that use different load sharing methods have been studied. Precise indexing and alignment of the geartrain to produce acceptable load sharing has been demonstrated. An elastomeric torque splitter that has large torsional compliance and damping produces even better load sharing while reducing dynamic transmission error and noise. However, the elastomeric torque splitter as now configured is not capable over the full range of operating conditions of a fielded system. A thrust balancing load sharing device was evaluated. Friction forces that oppose the motion of the balance mechanism are significant. A static analysis suggests increasing the helix angle of the input pinion of the thrust balancing design. Also, dynamic analysis of this design predicts good load sharing and significant torsional response to accumulative pitch errors of the gears.

  8. Critical Thoughts on Critical Thinking

    ERIC Educational Resources Information Center

    Cody, Dean E.

    2006-01-01

    Scholars in many academic areas, including librarians, devote a significant amount of thought to critical thinking. Surveying views of its use and possibility, the author considers some key librarians' thoughts on critical thinking. In conclusion, the inability to define critical thinking means that librarians need to emphasize control of…

  9. Critical Thinking vs. Critical Consciousness

    ERIC Educational Resources Information Center

    Doughty, Howard A.

    2006-01-01

    This article explores four kinds of critical thinking. The first is found in Socratic dialogues, which employ critical thinking mainly to reveal logical fallacies in common opinions, thus cleansing superior minds of error and leaving philosophers free to contemplate universal verities. The second is critical interpretation (hermeneutics) which…

  10. Critically Thinking about Critical Thinking

    ERIC Educational Resources Information Center

    Weissberg, Robert

    2013-01-01

    In this article, the author states that "critical thinking" has mesmerized academics across the political spectrum and that even high school students are now being called upon to "think critically." He furthers adds that it is no exaggeration to say that "critical thinking" has quickly evolved into a scholarly…

  11. How Critical Is Critical Thinking?

    ERIC Educational Resources Information Center

    Shaw, Ryan D.

    2014-01-01

    Recent educational discourse is full of references to the value of critical thinking as a 21st-century skill. In music education, critical thinking has been discussed in relation to problem solving and music listening, and some researchers suggest that training in critical thinking can improve students' responses to music. But what exactly is…

  12. Experiment Configurations for the DAST

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This image shows three vehicle configurations considered for the Drones for Aerodynamic and Structural Testing (DAST) program, conducted at NASA's Dryden Flight Research Center between 1977 and 1983. The DAST project planned for three wing configurations. These were the Instrumented Standard Wing (ISW), the Aeroelastic Research Wing-1 (ARW-1), and the ARW-2. After the DAST-1 crash, project personnel fitted a second Firebee II with a rebuilt ARW-1 wing. Due to the project's ending, it never flew the ARW-2 wing. These are the image contact sheets for each image resolution of the NASA Dryden Drones for Aerodynamic and Structural Testing (DAST) Photo Gallery. From 1977 to 1983, the Dryden Flight Research Center, Edwards, California, (under two different names) conducted the DAST Program as a high-risk flight experiment using a ground-controlled, pilotless aircraft. Described by NASA engineers as a 'wind tunnel in the sky,' the DAST was a specially modified Teledyne-Ryan BQM-34E/F Firebee II supersonic target drone that was flown to validate theoretical predictions under actual flight conditions in a joint project with the Langley Research Center, Hampton, Virginia. The DAST Program merged advances in electronic remote control systems with advances in airplane design. Drones (remotely controlled, missile-like vehicles initially developed to serve as gunnery targets) had been deployed successfully during the Vietnamese conflict as reconnaissance aircraft. After the war, the energy crisis of the 1970s led NASA to seek new ways to cut fuel use and improve airplane efficiency. The DAST Program's drones provided an economical, fuel-conscious method for conducting in-flight experiments from a remote ground site. DAST explored the technology required to build wing structures with less than normal stiffness. This was done because stiffness requires structural weight but ensures freedom from flutter-an uncontrolled, divergent oscillation of the structure, driven by aerodynamic

  13. 14 CFR 23.341 - Gust loads factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... from gusts specified in § 23.333(c). (b) The gust load for a canard or tandem wing configuration must... (slugs/cu.ft.); W/S=Wing loading (p.s.f.) due to the applicable weight of the airplane in the particular load case. W/S=Wing loading (p.s.f.); C=Mean geometric chord (ft.); g=Acceleration due to gravity...

  14. 14 CFR 23.341 - Gust loads factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... from gusts specified in § 23.333(c). (b) The gust load for a canard or tandem wing configuration must... (slugs/cu.ft.); W/S=Wing loading (p.s.f.) due to the applicable weight of the airplane in the particular load case. W/S=Wing loading (p.s.f.); C=Mean geometric chord (ft.); g=Acceleration due to gravity...

  15. Configurational entropy in thermoset polymers.

    PubMed

    Jensen, Martin; Jakobsen, Johnny

    2015-04-30

    The configurational entropy describes the atomic structure in a material and controls several material properties. Often the configurational entropy is determined through dielectric or calorimetric measurements where the difference between the entropies of the crystalline state and the amorphous state is determined. Many amorphous materials such as thermoset polymers have a high crystallization barrier, greatly limiting the applicability of the existing methods for determining the configurational entropy. In this work, a novel differential scanning calorimetry (DSC) method, based on measurement of the glass transition temperature at different heating rates, for determination of the configurational entropy is introduced. The theory behind the method has a universal character for amorphous materials, as it solely involves measurement of the glass transition temperature. The temperature dependency of the configurational entropy is determined for epoxy resins and PMMA (poly(methyl methacrylate)) to demonstrate the versatility of the method. On the basis of the findings of the introduced method, the influence of the degree of cross-linking and the chemical structure of the network is discussed. PMID:25844504

  16. Self-weight loading of horizontal hydraulic cylinders with axial load

    NASA Astrophysics Data System (ADS)

    Hale, J. M.; Sim, Ee Yu

    2016-05-01

    An iterative matrix method is described to determine the deformed shape of a horizontal stepped tube with large axial load, representing a heavy hydraulic cylinder. The method is applicable to both simply supported (pinned-pinned) and clamped-clamped end constraints. The clamped-clamped case is extended to include rotational compliance in the clamps. Using this analysis, radial loads on the piston seals of the cylinder are determined. Comparison is made between the seal loading of a typical large cylinder in pinned-pinned and clamped-clamped configurations, respectively. It is shown that the seal loading can be considerably reduced by the use of the clamped-clamped configuration provided the ends can be well aligned, but that the load is sensitive to angular misalignment.

  17. Gearbox Reliability Collaborative (GRC) Description and Loading

    SciTech Connect

    Oyague, F.

    2011-11-01

    This document describes simulated turbine load cases in accordance to the IEC 61400-1 Ed.3 standard, which is representative of the typical wind turbine design process. The information presented herein is intended to provide a broad understanding of the gearbox reliability collaborative 750kW drivetrain and turbine configuration. In addition, fatigue and ultimate strength drivetrain loads resulting from simulations are presented. This information provides the bases for the analytical work of the gearbox reliability collaborative effort.

  18. Configuration evaluation and criteria plan. Volume 2: Evaluation criteria plan (update). Space Transportation Main Engine (STME) configuration study

    NASA Technical Reports Server (NTRS)

    Bair, E. K.

    1987-01-01

    Candidate main engine configurations which enhance vehicle performance, operation and cost are identified. These candidate configurations are evaluated and the configurations which provide significant advantages over existing systems are selected for consideration for the next generation of launch vehicles. The unbiased selection of the Space Transportation Main Engine (STME) configuration requires that the candidate engines be evaluated against a predetermined set of criteria which must be properly weighted to emphasize critical requirements defined prior to the actual evaluation. During a prior study of the STME a Gas Generator Cycle engine was selected for conceptual design, with emphasis on reusability, reliability and low cost while achieving good performance. In this study emphasis is on expendable application of the STME while maintaining low cost and high reliability.

  19. Critical Care

    MedlinePlus

    Critical care helps people with life-threatening injuries and illnesses. It might treat problems such as complications from surgery, accidents, infections, and severe breathing problems. It involves ...

  20. Configurable silicon photonic crystal waveguides

    SciTech Connect

    Prorok, Stefan; Petrov, Alexander; Eich, Manfred; Luo, Jingdong; Jen, Alex K.-Y.

    2013-12-23

    In this Letter, we demonstrate that the mode cut off of a photonic crystal waveguide can be trimmed with high accuracy by electron beam bleaching of a chromophore doped polymer cladding. Using this method, configurable waveguides are realized, which allow for spatially resolved changes of the photonic crystal's effective lattice constant as small as 7.6 pm. We show three different examples how to take advantage of configurable photonic crystal waveguides: Shifting of the complete transmission spectrum, definition of cavities with high quality factor, and tuning of existing cavities.

  1. Runway configuration improvement programming model.

    NASA Technical Reports Server (NTRS)

    Yu, J. C.; Gibson, D. R.

    1973-01-01

    The basic objectives of the study were to subject a set of runway configurations to cost analysis and to develop a dynamic programming model which would enable an airport to economically match the ground capacity to its air traffic demand. Quantitative differences in the capacity of runway configurations result from the various aircraft/aircraft and aircraft/air-system interactions. A problem formulation and solution procedure is presented which is intended to be a meaningful technique for the long-range planning of runway expansion programs.

  2. Configurable silicon photonic crystal waveguides

    NASA Astrophysics Data System (ADS)

    Prorok, Stefan; Petrov, Alexander; Eich, Manfred; Luo, Jingdong; Jen, Alex K.-Y.

    2013-12-01

    In this Letter, we demonstrate that the mode cut off of a photonic crystal waveguide can be trimmed with high accuracy by electron beam bleaching of a chromophore doped polymer cladding. Using this method, configurable waveguides are realized, which allow for spatially resolved changes of the photonic crystal's effective lattice constant as small as 7.6 pm. We show three different examples how to take advantage of configurable photonic crystal waveguides: Shifting of the complete transmission spectrum, definition of cavities with high quality factor, and tuning of existing cavities.

  3. Experimental transonic flutter characteristics of supersonic cruise configurations

    NASA Technical Reports Server (NTRS)

    Durham, Michael H.; Cole, Stanley R.; Cazier, F. W., Jr.; Keller, Donald F.; Parker, Ellen C.; Wilkie, W. Keats

    1990-01-01

    The flutter characteristics of a generic arrow-wing supersonic transport configuration are studied. The wing configuration has a 3 percent biconvex airfoil and a leading-edge sweep of 73 deg out to a cranked tip with a 60 deg leading-edge sweep. The ground vibration tests and flutter test procedure are described. The effects of flutter on engine nacelles, fuel loading, wing-mounted vertical fin, wing angle-of-attack, and wing tip mass and stiffness distributions are analyzed. The data reveal that engine nacelles reduce the transonic flutter dynamic pressure by 25-30 percent; fuel loadings decrease dynamic pressures by 25 percent; 4-6 deg wing angles-of-attack cause steep transonic boundaries; and 5-10 percent changes in flutter dynamic pressures are the result of the wing-mounted vertical fin and wing-tip mass and stiffness distributions.

  4. 14 CFR 29.865 - External loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used...-load combinations to be used for nonhuman external cargo except for the failure of critical...

  5. 14 CFR 29.865 - External loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used...-load combinations to be used for nonhuman external cargo except for the failure of critical...

  6. 14 CFR 29.865 - External loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used...-load combinations to be used for nonhuman external cargo except for the failure of critical...

  7. 14 CFR 29.865 - External loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used...-load combinations to be used for nonhuman external cargo except for the failure of critical...

  8. Heat-load simulator for heat sink design

    NASA Technical Reports Server (NTRS)

    Dunleavy, A. M.; Vaughn, T. J.

    1968-01-01

    Heat-load simulator is fabricated from 1/4-inch aluminum plate with a contact surface equal in dimensions and configuration to those of the electronic installation. The method controls thermal output to simulate actual electronic component thermal output.

  9. Space segment configuration of the Canadian mobile satellite system

    NASA Technical Reports Server (NTRS)

    Bertenyi, Elemer

    1990-01-01

    The performance requirements, the main parameters, and the configuration of the MSAT spacecraft are reviewed. The major features of the communications subsystem are discussed in some detail. Key technology items include the L-band Radio Frequency (RF) power amplifier which must operate with a high DC to RF power efficiency and generate low intermodulation when loaded with multi-carrier signals; and the large diameter deployable L-band antenna. The development status and expected performance of these spacecraft components is examined.

  10. JWST ISIM Primary Structure and Kinematic Mount Configuration

    NASA Technical Reports Server (NTRS)

    Bartoszyk, Andrew; Carnahan, Tim; Hendricks, Steve; Kaprielian, Charles; Kuhn, Jonathan; Kunt, Cengiz

    2004-01-01

    In this presentation we will review the evolution of the ISIM primary structure tube topology and kinematic mount configuration to the current baseline concept. We will also show optimization procedures used and challenges resulting from complex joints under launch loads. Two additional key ISIM structure challenges of meeting thermal distortion and stability requirements and metal-composite bonded joint survivability at cryogenic temperatures are covered in other presentations.

  11. Bi-2223 HTS winding in toroidal configuration for SMES coil

    NASA Astrophysics Data System (ADS)

    Kondratowicz-Kucewicz, B.; Janowski, T.; Kozak, S.; Kozak, J.; Wojtasiewicz, G.; Majka, M.

    2010-06-01

    Energy can be stored in the magnetic field of a coil. Superconducting Magnetic Energy Storage (SMES) is very promising as a power storage system for load levelling or power stabilizer. However, the strong electromagnetic force caused by high magnetic field and large coil current is a problem in SMES systems. A toroidal configuration would have a much less extensive external magnetic field and electromagnetic forces in winding. The paper describes the design of HTS winding for SMES coil in modular toroid configuration consist of seven Bi-2223 double-pancakes as well as numerical analysis of SMES magnet model using FLUX 3D package. As the results of analysis the paper presents the optimal coil configuration and the parameters such as radius of toroidal magnet, energy stored in magnet and magnetic field distribution.

  12. Critical Muralism

    ERIC Educational Resources Information Center

    Rosette, Arturo

    2009-01-01

    This study focuses on the development and practices of Critical Muralists--community-educator-artist-leader-activists--and situates these specifically in relation to the Mexican mural tradition of los Tres Grandes and in relation to the history of public art more generally. The study examines how Critical Muralists address artistic and…

  13. A Communication Configuration of AIDS.

    ERIC Educational Resources Information Center

    Hughey, Jim D.

    A study focused on the way that image, knowledge, behavioral intent, and communicative responsiveness are configured for Acquired Immunodeficiency Syndrome (AIDS). The classic model of the adoption process expects that knowledge about a subject will lead to a favorable evaluation of it, which in turn will lead to a decision to act. But the…

  14. Inversion and Configuration of Faces.

    ERIC Educational Resources Information Center

    Bartlett, James C.; Searcy, Jean

    1993-01-01

    The Thatcher illusion, in which the inverted mouth and eyes of a face appear grotesque when upright, but not when the whole configuration is inverted, was studied in 3 experiments involving 89 undergraduates. Results suggest that the illusion represents a disruption of encoding of holistic information when faces are inverted. (SLD)

  15. Configuration Effects on Liner Performance

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Brown, Martha C.; Jones, Michael G.; Howerton, Brian M.

    2012-01-01

    The acoustic performance of a duct liner depends not only on the intrinsic properties of the liner but also on the configuration of the duct in which it is used. A series of experiments is performed in the NASA Langley Research Center Curved Duct Test Rig (at Mach 0.275) to evaluate the effect of duct configuration on the acoustic performance of single degree of freedom perforate-over-honeycomb liners. The liners form the sidewalls of the duct's test section. Variations of duct configuration include: asymmetric (liner on one side and hard wall opposite) and symmetric (liner on both sides) wall treatment; inlet and exhaust orientation, in which the sound propagates either against or with the flow; and straight and curved flow path. The effect that duct configuration has on the overall acoustic performance, particularly the shift in frequency and magnitude of peak attenuation, is quantified. The redistribution of incident mode content is shown. The liners constitute the side walls of the liner test section and the scatter of incident horizontal order 1 mode by the asymmetric treatment and order 2 mode by the symmetric treatment into order 0 mode is shown. Scatter of order 0 incident modes into higher order modes is also shown. This redistribution of mode content is significant because it indicates that the liner design can be manipulated such that energy is scattered into more highly attenuated modes, thus enhancing liner performance.

  16. NCCDS configuration management process improvement

    NASA Technical Reports Server (NTRS)

    Shay, Kathy

    1993-01-01

    By concentrating on defining and improving specific Configuration Management (CM) functions, processes, procedures, personnel selection/development, and tools, internal and external customers received improved CM services. Job performance within the section increased in both satisfaction and output. Participation in achieving major improvements has led to the delivery of consistent quality CM products as well as significant decreases in every measured CM metrics category.

  17. Configuration Aerodynamics: Past - Present - Future

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Agrawal, Shreekant; Bencze, Daniel P.; Kulfan, Robert M.; Wilson, Douglas L.

    1999-01-01

    The Configuration Aerodynamics (CA) element of the High Speed Research (HSR) program is managed by a joint NASA and Industry team, referred to as the Technology Integration Development (ITD) team. This team is responsible for the development of a broad range of technologies for improved aerodynamic performance and stability and control characteristics at subsonic to supersonic flight conditions. These objectives are pursued through the aggressive use of advanced experimental test techniques and state of the art computational methods. As the HSR program matures and transitions into the next phase the objectives of the Configuration Aerodynamics ITD are being refined to address the drag reduction needs and stability and control requirements of High Speed Civil Transport (HSCT) aircraft. In addition, the experimental and computational tools are being refined and improved to meet these challenges. The presentation will review the work performed within the Configuration Aerodynamics element in 1994 and 1995 and then discuss the plans for the 1996-1998 time period. The final portion of the presentation will review several observations of the HSR program and the design activity within Configuration Aerodynamics.

  18. Configural Processing and Face Viewpoint

    ERIC Educational Resources Information Center

    McKone, Elinor

    2008-01-01

    Configural/holistic processing, a key property of face recognition, has previously been examined only for front views of faces. Here, 6 experiments tested front (0 degree), three-quarter (45 degree), and profile views (90 degree), using composite and peripheral inversion tasks. Results showed an overall disadvantage in identifying profiles. This…

  19. HotSpot Software Configuration Management Plan

    SciTech Connect

    Walker, H; Homann, S G

    2009-03-12

    This Software Configuration Management Plan (SCMP) describes the software configuration management procedures used to ensure that the HotSpot dispersion model meets the requirements of its user base, which includes: (1) Users of the PC version of HotSpot for consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. This plan is intended to meet Critical Recommendations 1 and 3 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

  20. Shock wave loading of Nickel based superalloy and microstructural features of the compacts

    NASA Astrophysics Data System (ADS)

    Sharma, A. D.; Sharma, A. K.; Thakur, N.

    2015-02-01

    Explosive shock wave loading has been employed to consolidate micro-sized nickel based IN718 superalloy powder. Cylindrical geometry configuring the various critical parameters with optimized detonation pressure has been used to consolidate the powder with desirable means. The thrust on the work is to compact the powder nearer to theoretical density having almost negligible density gradient and without melting the core of the specimen. XRD study indicates that the crystal structure of the post compacts remains the same. Shock wave loading deformed the particles as has been inferred from SEM. The variation in particle size has been measured from Laser Diffraction based Particle Size Analyzer (LDPSA). It is found that this is a rapid fast technique to produce larger and crack free compacts of metal powders without their melting and with less particle size variation.

  1. High-Energy Electron Confinement in a Magnetic Cusp Configuration

    NASA Astrophysics Data System (ADS)

    Park, Jaeyoung; Krall, Nicholas A.; Sieck, Paul E.; Offermann, Dustin T.; Skillicorn, Michael; Sanchez, Andrew; Davis, Kevin; Alderson, Eric; Lapenta, Giovanni

    2015-04-01

    We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when β (plasma pressure/magnetic field pressure) is of order unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high β a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. While not able to confirm the details of Grad's work, the current experiment does validate, for the first time, the conjecture that confinement is substantially improved at high β . This represents critical progress toward an understanding of the plasma dynamics in a high-β cusp system. We hope that these results will stimulate a renewed interest in the cusp configuration as a fusion confinement candidate. In addition, the enhanced high-energy electron confinement resolves a key impediment to progress of the Polywell fusion concept, which combines a high-β cusp configuration with electrostatic fusion for a compact, power-producing nuclear fusion reactor.

  2. Nonequilibrium dynamics of emergent field configurations

    NASA Astrophysics Data System (ADS)

    Howell, Rafael Cassidy

    The processes by which nonlinear physical systems approach thermal equilibrium is of great importance in many areas of science. Central to this is the mechanism by which energy is transferred between the many degrees of freedom comprising these systems. With this in mind, in this research the nonequilibrium dynamics of nonperturbative fluctuations within Ginzburg-Landau models are investigated. In particular, two questions are addressed. In both cases the system is initially prepared in one of two minima of a double-well potential. First, within the context of a (2 + 1) dimensional field theory, we investigate whether emergent spatio-temporal coherent structures play a dynamcal role in the equilibration of the field. We find that the answer is sensitive to the initial temperature of the system. At low initial temperatures, the dynamics are well approximated with a time-dependent mean-field theory. For higher temperatures, the strong nonlinear coupling between the modes in the field does give rise to the synchronized emergence of coherent spatio-temporal configurations, identified with oscillons. These are long-lived coherent field configurations characterized by their persistent oscillatory behavior at their core. This initial global emergence is seen to be a consequence of resonant behavior in the long wavelength modes in the system. A second question concerns the emergence of disorder in a highly viscous system modeled by a (3 + 1) dimensional field theory. An integro-differential Boltzmann equation is derived to model the thermal nucleation of precursors of one phase within the homogeneous background. The fraction of the volume populated by these precursors is computed as a function of temperature. This model is capable of describing the onset of percolation, characterizing the approach to criticality (i.e. disorder). It also provides a nonperturbative correction to the critical temperature based on the nonequilibrium dynamics of the system.

  3. Configuration based Collisional-Radiative Model including configuration interaction

    NASA Astrophysics Data System (ADS)

    Busquet, Michel

    2007-11-01

    Atomic levels mixing through Configuration Interaction (CI) yields important effects. It transfers oscillator strengthes from allowed lines to forbidden lines, and produces strong shift and broadening of line arrays, although the total emissivity is almost insensitive to CI, being proportional to the average wave number. However for hi Z material, like Xe or Sn (potential xuv-ray source for micro-lithography), a non-LTE calculation accounting for all relevant levels wiill be untractable with billions of states. The model we constructed, CAVCRM (caf'e-crème), is a non-LTE C.R.M. where states are configurations but it includes C.I. to give full richness of spectral quantities, using the latest version of the HULLAC-v9 suite of codes and our newly developped algorithm for large set of states with as many as 50,000 states [1]. [1] M.Klapisch et al, this conference

  4. Mapping HIV community viral load: space, power and the government of bodies

    PubMed Central

    Gagnon, Marilou; Guta, Adrian

    2012-01-01

    HIV plasma viral load testing has become more than just a clinical tool to monitor treatment response at the individual level. Increasingly, individual HIV plasma viral load testing is being reported to public health agencies and is used to inform epidemiological surveillance and monitor the presence of the virus collectively using techniques to measure ‘community viral load’. This article seeks to formulate a critique and propose a novel way of theorizing community viral load. Based on the salient work of Michel Foucault, especially the governmentality literature, this article critically examines the use of community viral load as a new strategy of government. Drawing also on the work of Miller and Rose, this article explores the deployment of ‘community’ through the re-configuration of space, the problematization of viral concentrations in specific microlocales, and the government (in the Foucauldian sense) of specific bodies which are seen as ‘risky’, dangerous and therefore, in need of attention. It also examines community viral load as a necessary precondition — forming the ‘conditions of possibility’ — for the recent shift to high impact prevention tactics that are being scaled up across North America. PMID:23060688

  5. Relevance of aerodynamic modelling for load reduction control strategies of two-bladed wind turbines

    NASA Astrophysics Data System (ADS)

    Luhmann, B.; Cheng, P. W.

    2014-06-01

    A new load reduction concept is being developed for the two-bladed prototype of the Skywind 3.5MW wind turbine. Due to transport and installation advantages both offshore and in complex terrain two-bladed turbine designs are potentially more cost-effective than comparable three-bladed configurations. A disadvantage of two-bladed wind turbines is the increased fatigue loading, which is a result of asymmetrically distributed rotor forces. The innovative load reduction concept of the Skywind prototype consists of a combination of cyclic pitch control and tumbling rotor kinematics to mitigate periodic structural loading. Aerodynamic design tools must be able to model correctly the advanced dynamics of the rotor. In this paper the impact of the aerodynamic modelling approach is investigated for critical operational modes of a two-bladed wind turbine. Using a lifting line free wake vortex code (FVM) the physical limitations of the classical blade element momentum theory (BEM) can be evaluated. During regular operation vertical shear and yawed inflow are the main contributors to periodic blade load asymmetry. It is shown that the near wake interaction of the blades under such conditions is not fully captured by the correction models of BEM approach. The differing prediction of local induction causes a high fatigue load uncertainty especially for two-bladed turbines. The implementation of both cyclic pitch control and a tumbling rotor can mitigate the fatigue loading by increasing the aerodynamic and structural damping. The influence of the time and space variant vorticity distribution in the near wake is evaluated in detail for different cyclic pitch control functions and tumble dynamics respectively. It is demonstrated that dynamic inflow as well as wake blade interaction have a significant impact on the calculated blade forces and need to be accounted for by the aerodynamic modelling approach. Aeroelastic simulations are carried out using the high fidelity multi body

  6. Accelerator driven sub-critical core

    DOEpatents

    McIntyre, Peter M; Sattarov, Akhdiyor

    2015-03-17

    Systems and methods for operating an accelerator driven sub-critical core. In one embodiment, a fission power generator includes a sub-critical core and a plurality of proton beam generators. Each of the proton beam generators is configured to concurrently provide a proton beam into a different area of the sub-critical core. Each proton beam scatters neutrons within the sub-critical core. The plurality of proton beam generators provides aggregate power to the sub-critical core, via the proton beams, to scatter neutrons sufficient to initiate fission in the sub-critical core.

  7. Alternative geographic configurations for Medicare payments to health maintenance organizations.

    PubMed

    Porell, F W; Tompkins, C P; Turner, W M

    1990-01-01

    Under prevailing legislation, Medicare payments to health maintenance organizations (HMOs) are based upon projected fee-for-service reimbursement levels for enrollees' county of residence. These rates have been criticized in light of substantial variations in rates among neighboring counties and large fluctuations in rates over time. In this study, the use of nine alternative configurations and the county itself were evaluated on the basis of payment-area homogeneity, payment rate stability, and policy criteria, including the fiscal impacts of reconfiguration on HMOs. The results revealed rather modest differences among most alternative configurations and do not lend strong support for payment area reconfiguration at this time. PMID:10113270

  8. Balancing Loads Among Robotic-Manipulator Arms

    NASA Technical Reports Server (NTRS)

    Kreutz, Kenneth K.; Lokshin, Anatole

    1990-01-01

    Paper presents rigorous mathematical approach to control of multiple robot arms simultaneously grasping one object. Mathematical development focuses on relationship between ability to control degrees of freedom of configuration and ability to control forces within grasped object and robot arms. Understanding of relationship leads to practical control schemes distributing load more equitably among all arms while grasping object with proper nondamaging forces.

  9. Critics and Criticism of Education

    ERIC Educational Resources Information Center

    Ornstein, Allan C.

    1977-01-01

    Radical educational critics, such as Edgar Friedenberg, Paul Goodman, A. S. Neill, John Holt, Jonathan Kozol, Herbert Kohl, James Herndon, and Ivan Illich, have few constructive goals, no strategy for broad change, and a disdain for modernization and compromise. Additionally, these critics, says the author, fail to consider social factors related…

  10. Methods and apparatus for rotor load control in wind turbines

    DOEpatents

    Moroz, Emilian Mieczyslaw

    2006-08-22

    A wind turbine having a rotor, at least one rotor blade, and a plurality of generators, of which a first generator is configured to provide power to an electric grid and a second generator is configured to provide power to the wind turbine during times of grid loss. The wind turbine is configured to utilize power provided by the second generator to reduce loads on the wind turbine during times of grid loss.

  11. Parametric study of a canard-configured transport using conceptual design optimization

    NASA Technical Reports Server (NTRS)

    Arbuckle, P. D.; Sliwa, S. M.

    1985-01-01

    Constrained-parameter optimization is used to perform optimal conceptual design of both canard and conventional configurations of a medium-range transport. A number of design constants and design constraints are systematically varied to compare the sensitivities of canard and conventional configurations to a variety of technology assumptions. Main-landing-gear location and canard surface high-lift performance are identified as critical design parameters for a statically stable, subsonic, canard-configured transport.

  12. The Structure of Magnetocentrifugal Jets and Winds I. Steady Mass Loading

    SciTech Connect

    Anderson, J.

    2004-12-15

    We present the results of a series of time-dependent numerical simulations of cold, magnetocentrifugally launched winds from accretion disks. The goal of this study is to determine how the mass loading from the disk affects the structure and dynamics of the wind for a given distribution of magnetic field. Our simulations span four and half decades of mass loading; in the context of a disk with a launching region from 0.1 AU to 1.0 AU around a 1M{circle_dot} star and a field strength of about 20 G at the inner disk edge, this amounts to mass loss rates of 1 x 10{sup -9} - 3 x 10{sup -5} M{circle_dot} yr{sup -1} from each side of the disk. We find that, as expected intuitively, the degree of collimation of the wind increases with mass loading; however even the ''lightest'' wind simulated is significantly collimated compared with the force-free magnetic configuration of the same magnetic flux distribution at the launching surface, which becomes radial at large distances. The implication is that for flows from young stellar objects a radial field approximation is inappropriate. Surprisingly, the terminal velocity of the wind and the magnetic lever arm are still well-described by the analytical solutions for a radial field geometry. We also find that the isodensity contours and Alfven surface are very nearly self-similar in mass loading. The wind becomes unsteady above some critical mass loading rate. The exact value of the critical rate depends on the (small) velocity with which we inject the material into the wind. For a small enough injection speed, we are able to obtain the first examples of a class of heavily-loaded magnetocentrifugal winds with magnetic fields completely dominated by the toroidal component all the way to the launching surface. The stability of such toroidally dominated winds in 3D will be the subject of a future investigation.

  13. Generalized Ellipsometry in Unusual Configurations

    SciTech Connect

    Jellison Jr, Gerald Earle; Holcomb, David Eugene; Hunn, John D; Rouleau, Christopher M; Wright, Gomez W

    2006-01-01

    Most ellipsometry experiments are performed by shining polarized light onto a sample at a large angle of incidence, and the results are interpreted in terms of thin film thicknesses and isotropic optical functions of the film or substrate. However, it is possible to alter the geometrical arrangement, either by observing the sample in transmission or at normal-incidence reflection. In both cases, the experiment is fundamentally the same, but the interpretation of the results is considerably different. Both configurations can be used in conjunction with microscope optics, allowing for images to be made of the sample. The results of three examples of these different configurations using the two-modulator generalized ellipsometer (2-MGE) are reported: (1) spectroscopic birefringence measurements of ZnO, (2) electric field-induced birefringence (Pockels effect) in GaAs, and (3) normal-incidence reflection anisotropy of highly oriented pyrolytic graphite (HOPG).

  14. Solar disk sextant optical configuration

    NASA Technical Reports Server (NTRS)

    Chiu, H.-Y.; Maier, E.; Schatten, K. H.; Sofia, S.

    1984-01-01

    In this paper the performance of a plausible configuration for the solar disk sextant, an instrument to be used to monitor the solar diameter, is evaluated. Overall system requirements are evaluated, and tolerable uncertainties are obtained. It is concluded that by using a beam splitting wedge, a folded optics design can be used to measure the solar diameter to an accuracy of 10 to the -6th, despite the greater aberrations present in such optical systems.

  15. Unlimited full configuration interaction calculations

    NASA Astrophysics Data System (ADS)

    Knowles, Peter J.; Handy, Nicholas C.

    1989-08-01

    In very large full configuration interaction (full CI), nearly all of the CI coefficients are very small. Calculations, using a newly developed algorithm which exploits this fact, on NH3 with a DZP basis are reported, involving 2×108 Slater determinants. Such calculations are impossible with other existing full CI codes. The new algorithm opens up the opportunity of full CI calculations which are unlimited in size.

  16. Stereoscopic Configurations To Minimize Distortions

    NASA Technical Reports Server (NTRS)

    Diner, Daniel B.

    1991-01-01

    Proposed television system provides two stereoscopic displays. Two-camera, two-monitor system used in various camera configurations and with stereoscopic images on monitors magnified to various degrees. Designed to satisfy observer's need to perceive spatial relationships accurately throughout workspace or to perceive them at high resolution in small region of workspace. Potential applications include industrial, medical, and entertainment imaging and monitoring and control of telemanipulators, telerobots, and remotely piloted vehicles.

  17. Predictive Modeling of Tokamak Configurations*

    NASA Astrophysics Data System (ADS)

    Casper, T. A.; Lodestro, L. L.; Pearlstein, L. D.; Bulmer, R. H.; Jong, R. A.; Kaiser, T. B.; Moller, J. M.

    2001-10-01

    The Corsica code provides comprehensive toroidal plasma simulation and design capabilities with current applications [1] to tokamak, reversed field pinch (RFP) and spheromak configurations. It calculates fixed and free boundary equilibria coupled to Ohm's law, sources, transport models and MHD stability modules. We are exploring operations scenarios for both the DIII-D and KSTAR tokamaks. We will present simulations of the effects of electron cyclotron heating (ECH) and current drive (ECCD) relevant to the Quiescent Double Barrier (QDB) regime on DIII-D exploring long pulse operation issues. KSTAR simulations using ECH/ECCD in negative central shear configurations explore evolution to steady state while shape evolution studies during current ramp up using a hyper-resistivity model investigate startup scenarios and limitations. Studies of high bootstrap fraction operation stimulated by recent ECH/ECCD experiments on DIIID will also be presented. [1] Pearlstein, L.D., et al, Predictive Modeling of Axisymmetric Toroidal Configurations, 28th EPS Conference on Controlled Fusion and Plasma Physics, Madeira, Portugal, June 18-22, 2001. * Work performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  18. Ringed Accretion Disks: Equilibrium Configurations

    NASA Astrophysics Data System (ADS)

    Pugliese, D.; Stuchlík, Z.

    2015-12-01

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  19. Method of recertifying a loaded bearing member

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor)

    1992-01-01

    A method is described of recertifying a loaded bearing member using ultrasound testing to compensate for different equipment configurations and temperature conditions. The standard frequency F1 of a reference block is determined via an ultrasonic tone burst generated by a first pulsed phased locked loop (P2L2) equipment configuration. Once a lock point number S is determined for F1, the reference frequency F1a of the reference block is determined at this lock point number via a second P2L2 equipment configuration to permit an equipment offset compensation factor Fo1=((F1-F1a)/F1)(1000000) to be determined. Next, a reference frequency F2 of the unloaded bearing member is determined using a second P2L2 equipment configuration and is then compensated for equipment offset errors via the relationship F2+F2(Fo1)/1000000. A lock point number b is also determined for F2. A resonant frequency F3 is determined for the reference block using a third P2L2 equipment configuration to determine a second offset compensation factor F02=((F1-F3)/F1) 1000000. Next the resonant frequency F4 of the loaded bearing member is measured at lock point number b via the third P2L2 equipment configuration and the bolt load determined by the relationship (-1000000)CI(((F2-F4)/F2)-Fo2), wherein CI is a factor correlating measured frequency shift to the applied load. Temperature compensation is also performed at each point in the process.

  20. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure. Part 1; Ultimate Design Loads

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses finite element analysis and testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part I of the paper considers the five most critical load conditions, which are internal pressure only and positive and negative g-loads with and without internal pressure. Analysis results are compared with measurements acquired during testing. Performance of the test article is found to be closely aligned with predictions and, consequently, able to support the hybrid wing body design loads in pristine and barely visible impact damage conditions.

  1. 21-PWR WASTE PACKAGE WITH ABSORBER PLATES LOADING CURVE EVALUATION

    SciTech Connect

    J.M. Scaglione

    2004-12-17

    The objective of this calculation is to evaluate the required minimum burnup as a function of initial pressurized water reactor (PWR) assembly enrichment that would permit loading of spent nuclear fuel into the 21 PWR waste package with absorber plates design as provided in Attachment IV. This calculation is an example of the application of the methodology presented in the ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003). The scope of this calculation covers a range of enrichments from 0 through 5.0 weight percent U-235, and a burnup range of 0 through 45 GWd/MTU. Higher burnups were not necessary because 45 GWd/MTU was high enough for the loading curve determination. This activity supports the validation of the use of burnup credit for commercial spent nuclear fuel applications. The intended use of these results will be in establishing PWR waste package configuration loading specifications. Limitations of this evaluation are as follows: (1) The results are based on burnup credit for actinides and selected fission products as proposed in YMP (2003, Table 3-1) and referred to as the ''Principal Isotopes''. Any change to the isotope listing will have a direct impact on the results of this report. (2) The results are based on 1.5 wt% Gd in the Ni-Gd Alloy material and having no tuff inside the waste package. If the Gd loading is reduced or a process to introduce tuff inside the waste package is defined, then this report would need to be reevaluated based on the alternative materials. This calculation is subject to the ''Quality Assurance Requirements and Description'' (QARD) (DOE 2004) because it concerns engineered barriers that are included in the ''Q-List'' (BSC 2004k, Appendix A) as items important to safety and waste isolation.

  2. Critical Transitions in Early Embryonic Aortic Arch Patterning and Hemodynamics

    PubMed Central

    Kowalski, William J.; Dur, Onur; Wang, Yajuan; Patrick, Michael J.; Tinney, Joseph P.; Keller, Bradley B.; Pekkan, Kerem

    2013-01-01

    Transformation from the bilaterally symmetric embryonic aortic arches to the mature great vessels is a complex morphogenetic process, requiring both vasculogenic and angiogenic mechanisms. Early aortic arch development occurs simultaneously with rapid changes in pulsatile blood flow, ventricular function, and downstream impedance in both invertebrate and vertebrate species. These dynamic biomechanical environmental landscapes provide critical epigenetic cues for vascular growth and remodeling. In our previous work, we examined hemodynamic loading and aortic arch growth in the chick embryo at Hamburger-Hamilton stages 18 and 24. We provided the first quantitative correlation between wall shear stress (WSS) and aortic arch diameter in the developing embryo, and observed that these two stages contained different aortic arch patterns with no inter-embryo variation. In the present study, we investigate these biomechanical events in the intermediate stage 21 to determine insights into this critical transition. We performed fluorescent dye microinjections to identify aortic arch patterns and measured diameters using both injection recordings and high-resolution optical coherence tomography. Flow and WSS were quantified with 3D computational fluid dynamics (CFD). Dye injections revealed that the transition in aortic arch pattern is not a uniform process and multiple configurations were documented at stage 21. CFD analysis showed that WSS is substantially elevated compared to both the previous (stage 18) and subsequent (stage 24) developmental time-points. These results demonstrate that acute increases in WSS are followed by a period of vascular remodeling to restore normative hemodynamic loading. Fluctuations in blood flow are one possible mechanism that impacts the timing of events such as aortic arch regression and generation, leading to the variable configurations at stage 21. Aortic arch variations noted during normal rapid vascular remodeling at stage 21 identify a

  3. Axial-Loading Circumferential Dovetail Turbine-Blade Mount

    NASA Technical Reports Server (NTRS)

    Pierce, Martin J.; Ward, Steven D.; Eskridge, Ronald R.

    1992-01-01

    In new configuration, retaining ring holds base of blades in circumferential dovetail slot. Blades inserted axially via loading slots into circumferential dovetail slot. Ring placed over loading slots and fastened with split ring held by arm of disk. Blades less likely to be shaken loose during operation.

  4. Stormwater Pollutant Control from Critical Source Areas

    EPA Science Inventory

    Critical source areas include: vehicular maintenance facilities, parking lots and bus terminals, junk and lumber yards, industrial storage facilities, loading docks and refueling areas, manufacturing sites, etc. Addressing pollutant runoff from these areas is an important compon...

  5. Vertical load capacities of roof truss cross members

    PubMed Central

    Gearhart, David F.; Morsy, Mohamed Khaled

    2016-01-01

    Trusses used for roof support in coal mines are constructed of two grouted bolts installed at opposing forty-five degree angles into the roof and a cross member that ties the angled bolts together. The load on the cross member is vertical, which is transverse to the longitudinal axis, and therefore the cross member is loaded in the weakest direction. Laboratory tests were conducted to determine the vertical load capacity and deflection of three different types of cross members. Single-point load tests, with the load applied in the center of the specimen and double-point load tests, with a span of 2.4 m, were conducted. For the single-point load configuration, the yield of the 25 mm solid bar cross member was nominally 98 kN of vertical load, achieved at 42 cm of deflection. For cable cross members, yield was not achieved even after 45 cm of deflection. Peak vertical loads were about 89 kN for 17 mm cables and 67 kN for the 15 mm cables. For the double-point load configurations, the 25 mm solid bar cross members yielded at 150 kN of vertical load and 25 cm of deflection. At 25 cm of deflection individual cable strands started breaking at 133 and 111 kN of vertical load for the 17 and 15 mm cable cross members respectively. PMID:27547484

  6. Multiple forearm robotic elbow configuration

    SciTech Connect

    Fisher, J.J.

    1990-09-11

    This patent describes a dual forearmed robotic elbow configuration comprises a main arm having a double elbow from which two coplanar forearms depend, two actuators carried in the double elbow for moving the forearms, and separate, independent end effectors, operated by a cable carried from the main arm through the elbow, is attached to the distal end of each forearm. Coiling the cables around the actuators prevents bending or kinking when the forearms are rotated 360 degrees. The end effectors can have similar or different capabilities. Actuator canisters within the dual elbow are modular for rapid replacement or maintenance. Coarse and fine resolver transducers within the actuators provide accurate position referencing information.

  7. Configuration optimization of space structures

    NASA Technical Reports Server (NTRS)

    Felippa, Carlos; Crivelli, Luis A.; Vandenbelt, David

    1991-01-01

    The objective is to develop a computer aid for the conceptual/initial design of aerospace structures, allowing configurations and shape to be apriori design variables. The topics are presented in viewgraph form and include the following: Kikuchi's homogenization method; a classical shape design problem; homogenization method steps; a 3D mechanical component design example; forming a homogenized finite element; a 2D optimization problem; treatment of volume inequality constraint; algorithms for the volume inequality constraint; object function derivatives--taking advantage of design locality; stiffness variations; variations of potential; and schematics of the optimization problem.

  8. Configurational diffusion of coal macromolecules

    SciTech Connect

    Guin, J.A.; Curtis, C.W.; Tarrer, A.R.

    1990-01-01

    As shown in last quarter's report on the configurational diffusion of coal macromolecules, the hindered diffusion data for both TPP and coal macromolecules were significantly different from the theoretical correlations. In order to evaluate the factors which could lead to this difference an error analysis was conducted, and the detailed results reported herein. Generally, we did not find any errors which could account for the deviation from the theory, and thus we conclude that this deviation is real and can be ascribed to some factor not considered by the hindered diffusion theory, i.e., attractive or repulsive forces. 2 refs., 4 figs., 4 tabs.

  9. Multiple forearm robotic elbow configuration

    SciTech Connect

    Fisher, John J.

    1990-01-01

    A dual forearmed robotic elbow configuration comprises a main arm having a double elbow from which two coplanar forearms depend, two actuators carried in the double elbow for moving the forearms, and separate, independent end effectors, operated by a cable carried from the main arm through the elbow, is attached to the distal end of each forearm. Coiling the cables around the actuators prevents bending or kinking when the forearms are rotated 360 degrees. The end effectors can have similar or different capabilities. Actuator cannisters within the dual elbow are modular for rapid replacement or maintenance. Coarse and fine resolver transducers within the actuators provide accurate position referencing information.

  10. Interface Configuration Experiment: Preliminary results

    SciTech Connect

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

    1993-09-01

    The Interface Configuration Experiment (ICE) was carried out on USML-1 to investigate liquid-gas interfaces in certain rotationally-symmetric containers having prescribed, mathematically derived shapes. These containers have the property that they admit an entire continuum of distinct equilibrium rotationally-symmetric interfaces for a given liquid volume and contact angle. Furthermore, it can be shown that none of these interfaces can be stable. It was found, after the containers were filled in orbit, that an initial equilibrium interface from the symmetric continuum reoriented, when perturbed, to a stable interface that was not rotationally symmetric, in accordance with the mathematical theory.

  11. Interface Configuration Experiment: Preliminary Results

    NASA Technical Reports Server (NTRS)

    Concus, Paul; Finn, Robert; Weislogel, Mark

    1994-01-01

    The Interface Configuration Experiment (ICE) was carried out on USML-1 to investigate liquid-gas interfaces in certain rotationally-symmetric containers having prescribed, mathematically derived shapes. These containers have the property that they admit an entire continuum of distinct equilibrium rotationally-symmetric interfaces for a given liquid volume and contact angle. Furthermore, it can be shown that none of these interfaces can be stable. It was found, after the containers were filled in orbit, that an initial equilibrium interface from the symmetric continuum re-oriented, when perturbed, to a stable interface that was not rotationally symmetric, in accordance with the mathematical theory.

  12. Dimensional regularization in configuration space

    SciTech Connect

    Bollini, C.G. |; Giambiagi, J.J.

    1996-05-01

    Dimensional regularization is introduced in configuration space by Fourier transforming in {nu} dimensions the perturbative momentum space Green functions. For this transformation, the Bochner theorem is used; no extra parameters, such as those of Feynman or Bogoliubov and Shirkov, are needed for convolutions. The regularized causal functions in {ital x} space have {nu}-dependent moderated singularities at the origin. They can be multiplied together and Fourier transformed (Bochner) without divergence problems. The usual ultraviolet divergences appear as poles of the resultant analytic functions of {nu}. Several examples are discussed. {copyright} {ital 1996 The American Physical Society.}

  13. Flicker Test as a Load Measurement During the Combined Effect of Heat and Noise.

    PubMed

    Luczak; Kurkus-Rozowska; Sobolewski

    1995-01-01

    This study was a joint physiological and psychological experiment undertaken in order to determine changes in physiological and psychological human functions under the combined influence of heat, noise and physical activity. Seven experimental situations were simulated in a climatic chamber, with different configurations of three independent variables: heat (40 degrees C), noise (98 dB) and physical effort (30% of maximum volume of oxygen uptake--V0&inf2; max). Five psychological variables (critical flicker fusion--CFF, hand tremor, reaction time, subjective climate evaluation and subjective evaluation of the given condition load) and two physiological variables (heart rate and rectal temperature) were monitored. Results indicate that CFF changed (increased) significantly when more than one experimental variable was applied. These changes coincided with significant changes in both subjective climate evaluation and subjective evaluation of a given condition load. There were no significant changes in psychomotor functions (hand tremor and reaction time). None of the observed physiological parameters were above the critical value. The results obtained let us suggest that CFF can be treated as a psychophysical load indicator. PMID:10603547

  14. Blank fire configuration for automatic pistol

    DOEpatents

    Teague, Tommy L.

    1990-01-01

    A pistol configured to fire blank cartridges includes a modified barrel with a breech portion connected to an aligned inner sleeve. Around the inner sleeve, there is disposed an outer sleeve having a vent therein through which the cartridge discharges. The breech portion is connected to a barrel anchor to move backward in a slight arc when the pistol is fired. A spring retention rod projects from the barrel anchor and receives a shortened recoil spring therearound which recoil spring has one end abutting a stop on the barrel anchor and the other end in abutment with the end of a spring retaining cup. The spring retaining cup is engaged by a flange projecting from a slide so that when the pistol is fired, the slide moves rearwardly against the compression of the spring to eject the spent cartridge and then moves forwardly under the urging of the spring to load a fresh cartridge into the breech portion. The spring then returns all of the slidable elements to their initial position so that the pistol may again be fired.

  15. Blank fire configuration for automatic pistol

    SciTech Connect

    Teague, T.L.

    1990-03-13

    This patent describes a pistol configured to fire blank cartridges that includes a modified barrel with a breech portion connected to an aligned inner sleeve. Around the inner sleeve, there is disposed an outer sleeve having a vent therein through which the cartridge discharges. The breech portion is connected to a barrel anchor to move backward in a slight arc when the pistol is fired. A spring retention rod projects from the barrel anchor and receives a shortened recoil spring therearound which recoil spring has one end abutting a stop on the barrel anchor and the other end in abutment with the end of a spring retaining cup. The spring retaining cup is engaged by a flange projecting from a slide so that when the pistol is fired, the slide moves rearwardly against the compression of the spring to eject the spent cartridge and then moves forwardly under the urging of the spring to load a fresh cartridge into the breech portion. The spring then returns all of the slidable elements to their initial position so that the pistol may again be fired.

  16. Blank fire configuration for automatic pistol

    SciTech Connect

    Teague, T.L.

    1988-08-31

    A pistol configured to fire blank cartridges includes a modified barrel with a breach portion connected to an aligned inner sleeve. Around the inner sleeve, there is disposed an outer sleeve having a vent therein through which the cartridge discharges. The breach portion is connected to a barrel anchor to move backward in a slight arc when the pistol is fired. A spring retaining rod projects from the barrel anchor and receives a coiled recoil spring therearound which recoil spring has one end abutting a stop on the barrel anchor and the other end in abutment with the end of a spring retaining cup. The spring retaining cup is engaged by a flange projecting from the slider so that when the pistol is fired, the slider moves rearwardly against the compression of the spring to eject the spent cartridge and then moves forwardly under the urging of the spring to load a fresh cartridge into the breach portion. The spring then returns all of the slidable elements to their initial position so that the pistol may again be fired. 4 figs.

  17. Cryogenics Testbed Laboratory Flange Baseline Configuration

    NASA Technical Reports Server (NTRS)

    Acuna, Marie Lei Ysabel D.

    2013-01-01

    As an intern at Kennedy Space Center (KSC), I was involved in research for the Fluids and Propulsion Division of the NASA Engineering (NE) Directorate. I was immersed in the Integrated Ground Operations Demonstration Units (IGODU) project for the majority of my time at KSC, primarily with the Ground Operations Demonstration Unit Liquid Oxygen (GODU L02) branch of IGODU. This project was established to develop advancements in cryogenic systems as a part of KSC's Advanced Exploration Systems (AES) program. The vision of AES is to develop new approaches for human exploration, and operations in and beyond low Earth orbit. Advanced cryogenic systems are crucial to minimize the consumable losses of cryogenic propellants, develop higher performance launch vehicles, and decrease operations cost for future launch programs. During my internship, I conducted a flange torque tracking study that established a baseline configuration for the flanges in the Simulated Propellant Loading System (SPLS) at the KSC Cryogenics Test Laboratory (CTL) - the testing environment for GODU L02.

  18. Measurement and analysis of critical CTOA for an aluminum alloy sheet

    NASA Technical Reports Server (NTRS)

    Dawicke, D. S.; Sutton, M. A.; Newman, J. C., Jr.; Bigelow, C. A.

    1993-01-01

    The stable tearing behavior of thin sheets of 2024-T3 aluminum alloy was investigated for middle crack tension, M(T), and compact tension, C(T), specimens. The surface crack-tip opening angle (CTOA), applied loads, crack extension, and local displacements were measured. A critical CTOA fracture criterion was incorporated into a two-dimensional, elastic plastic finite element code and used to simulate the experimental fracture behavior. The CTOA measurements and observations of the fracture surfaces have shown that large values for surface CTOA were observed for small crack extensions (less than the sheet thickness); substantial tunneling of the crack was associated with small crack extensions; crack tunneling in the M(T) specimen was less than that observed in the C(T) configuration; for larger crack extensions, the measured CTOA values were determined to be approximately 6 degrees for both the M(T) and C(T) configuration; and for larger crack extensions, crack tunneling remained constant. The two-dimensional finite element predictions of fracture behavior assumed a constant critical CTOA value of 6 degrees and accounted for local crack tip constraint with a plane strain core of elements ahead of the crack tip. The plane strain core extended 5 mm above the crack plane. The simulations were within +/- 4 percent of the maximum applied load for the C(T) tests within 2 percent for the M(T) tests.

  19. Microscopic Approaches to Nuclear Structure: Configuration Interaction

    SciTech Connect

    Ormand, W E

    2007-09-21

    The configuration interaction (CI) approach to solving the nuclear many-body problem, also known as the interacting shell model, has proven to be powerful tool in understanding the structure of nuclei. The principal criticism of past applications of the shell model is the reliance on empirical tuning to interaction matrix elements. If an accurate description of nuclei far from the valley of stability, where little or no data is available, a more fundamental approach is needed. This starts with recent ab initio approaches with effective interactions in the no-core shell model (NCSM). Using effective-field theory for guidance, fully ab initio descriptions of nuclei up to {sup 16}O with QCD based NN, NNN, and NNNN interactions will be possible within the next five years. An important task is then to determine how to use these NCSM results to develop effective interactions to describe heavier nuclei without the need to resort to an empirical retuning with every model space. Thus, it is likely that more traditional CI applications utilizing direct diagonalization and more fundamental interactions will be applicable to nuclei with perhaps up to one hundred constituents. But, these direct diagonalization CI applications will always be computationally limited due to the rapid increase in the number of configurations with particle number. Very recently, the shifted-contour method has been applied to the Auxiliary-field Monte Carlo approach to the Shell Model (AFMCSM), and preliminary applications exhibit a remarkable taming of the notorious sign problem. If the mitigation of the sign problem holds true, the AFMCSM will offer a method to compute quantum correlations to mean-field applications for just about all nuclei; giving exact results for CI model spaces that can approach 10{sup 20-25}. In these lectures, I will discuss modern applications of CI to the nuclear many-body problem that have the potential to guide nuclear structure theory into the next decade.

  20. Using HPC within an operational forecasting configuration

    NASA Astrophysics Data System (ADS)

    Jagers, H. R. A.; Genseberger, M.; van den Broek, M. A. F. H.

    2012-04-01

    Various natural disasters are caused by high-intensity events, for example: extreme rainfall can in a short time cause major damage in river catchments, storms can cause havoc in coastal areas. To assist emergency response teams in operational decisions, it's important to have reliable information and predictions as soon as possible. This starts before the event by providing early warnings about imminent risks and estimated probabilities of possible scenarios. In the context of various applications worldwide, Deltares has developed an open and highly configurable forecasting and early warning system: Delft-FEWS. Finding the right balance between simulation time (and hence prediction lead time) and simulation accuracy and detail is challenging. Model resolution may be crucial to capture certain critical physical processes. Uncertainty in forcing conditions may require running large ensembles of models; data assimilation techniques may require additional ensembles and repeated simulations. The computational demand is steadily increasing and data streams become bigger. Using HPC resources is a logical step; in different settings Delft-FEWS has been configured to take advantage of distributed computational resources available to improve and accelerate the forecasting process (e.g. Montanari et al, 2006). We will illustrate the system by means of a couple of practical applications including the real-time dynamic forecasting of wind driven waves, flow of water, and wave overtopping at dikes of Lake IJssel and neighboring lakes in the center of The Netherlands. Montanari et al., 2006. Development of an ensemble flood forecasting system for the Po river basin, First MAP D-PHASE Scientific Meeting, 6-8 November 2006, Vienna, Austria.

  1. Systems and methods for providing power to a load based upon a control strategy

    SciTech Connect

    Perisic, Milun; Lawrence, Christopher P; Ransom, Ray M; Kajouke, Lateef A

    2014-11-04

    Systems and methods are provided for an electrical system. The electrical system, for example, includes a first load, an interface configured to receive a voltage from a voltage source, and a controller configured to receive the voltage through the interface and to provide a voltage and current to the first load. The controller may be further configured to, receive information on a second load electrically connected to the voltage source, determine an amount of reactive current to return to the voltage source such that a current drawn by the electrical system and the second load from the voltage source is substantially real, and provide the determined reactive current to the voltage source.

  2. Critical Thinking

    ERIC Educational Resources Information Center

    Villano, Matt

    2006-01-01

    True excellence in technology implementation emerges when IT, administrative, and academic leaders link IT to mission-critical institutional objectives, investing in hardware and software to serve an explicit purpose and a distinct population of users. This article illustrates that at public institutions of higher education in New Hampshire as…

  3. Configurational diffusion of coal macromolecules

    SciTech Connect

    Guin, J.A.; Curtis, C.W.; Tarrer, A.R.; Kim, S.; Hwang, D.; Chen, C.C.; Chiou, Z.

    1991-01-01

    The objective of our research was to obtain fundamental information regarding the functional dependence of the diffusion coefficient of coal molecules on the ratio of molecule to pore diameter. That is, the objective of our study was to examine the effect of molecule size and configuration on hindered diffusion of coal macromolecules through as porous medium. To best accomplish this task, we circumvented the complexities of an actual porous catalyst by using a well defined porous matrix with uniform capillaric pores, i.e., a track-etched membrane. In this way, useful information was obtained regarding the relationship of molecular size and configuration on the diffusion rate of coal derived macromolecules through a pore structure with known geometry. Similar studies were performed using a pellet formed of porous alumina, to provide a link between the idealized membranes and the actual complex pore structure of real catalyst extrudates. The fundamental information from our study will be useful toward the tailoring of catalysts to minimize diffusional influences and thereby increase coal conversion and selectivity for desirable products. (VC)

  4. Vertical and horizontal access configurations

    SciTech Connect

    Spampinato, P.T.

    1987-01-01

    A number of configuration features and maintenance operations are influenced by the choice of whether a design is based on vertical or horizontal access for replacing reactor components. The features which are impacted most include the first wall/blanket segmentation, the poloidal field coil locations, the toroidal field coil number and size, access port size for in-vessel components, and facilities. Since either configuration can be made to work, the choice between the two is not clear cut because both have certain advantages. It is apparent that there are large cost benefits in the poloidal field coil system for ideal coil locations for high elongation plasmas and marginal savings for the INTOR case. If we assume that a new tokamak design will require a higher plasma elongation, the recommendation is to arrange the poloidal field coils in a cost-effective manner while providing reasonable midplane access for heating interfaces and test modules. If a new design study is not based on a high elongation plasma, it still appears prudent to consider this approach so that in-vessel maintenance can be accomplished without moving very massive structures such as the bulk shield. 10 refs., 29 figs., 3 tabs.

  5. Computational methods for stellerator configurations

    NASA Astrophysics Data System (ADS)

    Betancourt, O.

    This project had two main objectives. The first one was to continue to develop computational methods for the study of three dimensional magnetic confinement configurations. The second one was to collaborate and interact with researchers in the field who can use these techniques to study and design fusion experiments. The first objective has been achieved with the development of the spectral code BETAS and the formulation of a new variational approach for the study of magnetic island formation in a self consistent fashion. The code can compute the correct island width corresponding to the saturated island, a result shown by comparing the computed island with the results of unstable tearing modes in Tokamaks and with experimental results in the IMS Stellarator. In addition to studying three dimensional nonlinear effects in Tokamaks configurations, these self consistent computed island equilibria will be used to study transport effects due to magnetic island formation and to nonlinearly bifurcated equilibria. The second objective was achieved through direct collaboration with Steve Hirshman at Oak Ridge, D. Anderson and R. Talmage at Wisconsin as well as through participation in the Sherwood and APS meetings.

  6. The configuration management program for the Emergency Management Support System

    SciTech Connect

    Probasco, K M; Stephan, E G

    1991-08-01

    Emergency response software is used increasingly by the US Department of Energy's (DOE's) Emergency Management Project (EMP) personnel at Hanford Site. This software must be reliable, of high quality, and capable of performing critical functions to support assessment of actual or potential consequences of any hazardous accidents onsite or events having potential offsite impacts. To better control the software and ensure its suitability for use as a tool to protect employees, the public, and environment, a method for specifying and certifying its capabilities and documenting its development and implementation was needed. A team of EMP staff, composed of personnel from Pacific Northwest Laboratory (PNL) and Boeing Computer Services- Richland (BCSR) under the direction of PNL EMP, responded to this need by developing a software configuration management program (CMP). This report documents the development of the CMP, including the strategies upon which the CMP is based, and describes the program as it has been implemented for EMS System software. The program relies on the integration of its three primary elements: the configuration management staff, tools, and process. Configuration management staff run the program, using specially designed configuration management forms to guide, document, and track the life cycle of the software. The configuration management process itself is reflected in the instructive forms and summarized in flowcharts representing each phase of the process -- from requirements specification through implementation and maintenance. 7 refs., 9 figs., 1 tab.

  7. A Numerical Investigation on Configurational Distortions in Nematic Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Pandolfi, Anna; Napoli, Gaetano

    2011-10-01

    When subjected to magnetic or electric fields, nematic liquid crystals confined between two parallel glass plates and initially uniformly oriented may undergo homogeneous one-dimensional spatial distortions (Fréedericksz and Zolina, Trans. Faraday Soc. 29:919, 1933) or periodic distortions (Lonberg and Meyer, Phys. Rev. Lett. 55(7):718-721, 1985; and Srajer et al., Phys. Rev. Lett. 67(9):1102-1105, 1991). According to the experimental observations, periodic phases are stable configurations at intermediate intensity of the acting field, while homogeneous phases are stable at higher strengths. We present a fully nonlinear finite element approach able to describe homogeneous and periodic configurational phases in a cell of confined nematic liquid crystal with strong planar anchoring boundary conditions. Stationary configurations are obtained by setting to zero the first variation of the discretized total energy of the system. Unstable configurations are identified by evaluating the behavior of the solution under small numerical perturbations. Numerical calculations are able to describe the evolution of the configurational distortions as a function of the applied field and are able to capture the critical points between homogeneous and periodic phases. The proposed approach has been proved to be an excellent tool to predict the existence of unstable or metastable distortions, characterized by higher energy levels.

  8. Equilibrium Configuration in a Nematic Liquid Crystal Droplet with Homeotropic Anchoring of Finite Strength

    NASA Astrophysics Data System (ADS)

    Kanke, Masaki; Sasaki, Kazuo

    2013-09-01

    Equilibrium configuration of order parameter in a nematic liquid crystal droplet with homeotropic anchoring of finite strength at the surface is studied numerically by using the Landau--de Gennes approach. It is found that a hedgehog-like configuration with a disclination loop of a small radius is stable for strong anchoring while an axial configuration without defect is stable for weak anchoring. A first-order phase transition from one configuration to the other occurs as the strength of the anchoring is varied. The critical anchoring strength turns out to increase almost linearly with the inverse of the droplet radius.

  9. Tank waste remediation system configuration management plan

    SciTech Connect

    Vann, J.M.

    1998-01-08

    The configuration management program for the Tank Waste Remediation System (TWRS) Project Mission supports management of the project baseline by providing the mechanisms to identify, document, and control the functional and physical characteristics of the products. This document is one of the tools used to develop and control the mission and work. It is an integrated approach for control of technical, cost, schedule, and administrative information necessary to manage the configurations for the TWRS Project Mission. Configuration management focuses on five principal activities: configuration management system management, configuration identification, configuration status accounting, change control, and configuration management assessments. TWRS Project personnel must execute work in a controlled fashion. Work must be performed by verbatim use of authorized and released technical information and documentation. Application of configuration management will be consistently applied across all TWRS Project activities and assessed accordingly. The Project Hanford Management Contract (PHMC) configuration management requirements are prescribed in HNF-MP-013, Configuration Management Plan (FDH 1997a). This TWRS Configuration Management Plan (CMP) implements those requirements and supersedes the Tank Waste Remediation System Configuration Management Program Plan described in Vann, 1996. HNF-SD-WM-CM-014, Tank Waste Remediation System Configuration Management Implementation Plan (Vann, 1997) will be revised to implement the requirements of this plan. This plan provides the responsibilities, actions and tools necessary to implement the requirements as defined in the above referenced documents.

  10. Biomechanical evaluation of 10 configurations of a small external fixator set.

    PubMed

    Katolik, Leonid I; Stewart, Mark; Fernandez, John; MacLennan, Allison; Cohen, Mark

    2008-09-01

    The small AO (Synthes, Paoli, Pa) external fixator is a valuable tool for the treatment of distal radius fractures. The construct has many possible bar and pin configurations. However, there are no data regarding which construct is optimal with respect to strength and versatility. We tested 10 configurations to determine bending stiffness, rotation, and axial loading. Although slight variations were found between constructs for bending and rotation forces, there were marked differences between constructs during axial loading. A frame design without bar-to-bar clamps was determined stiffest. However, this configuration may be more difficult to apply and adjust in the clinical setting. Although an "ideal" construct applicable to all fracture types does not exist, knowledge of the strengths of various configurations may allow for optimization of fixator assembly to meet specific clinical needs. PMID:18982182

  11. Evaluating the effects of loading parameters on single-crystal slip in tantalum using molecular mechanics

    NASA Astrophysics Data System (ADS)

    Alleman, Coleman; Ghosh, Somnath; Luscher, D. J.; Bronkhorst, Curt A.

    2014-01-01

    This study is aimed at developing a physics-based crystal plasticity finite element model for body-centred cubic (BCC) metals, through the introduction of atomic-level deformation information from molecular dynamics (MD) investigations of dislocation motion at the onset of plastic flow. In this study, three critical variables governing crystal plasticity mediated by dislocation motion are considered. MD simulations are first performed across a range of finite temperatures up to 600K to quantify the temperature dependence of critical stress required for slip initiation. An important feature of slip in BCC metals is that it is not solely dependent on the Schmid law measure of resolved shear stress, commonly employed in crystal plasticity models. The configuration of a screw dislocation and its subsequent motion is studied under different load orientations to quantify these non-Schmid effects. Finally, the influence of strain rates on thermal activation is studied by inducing higher stresses during activation at higher applied strain rates. Functional dependence of the critical resolved shear stress on temperature, loading orientation and strain rate is determined from the MD simulation results. The functional forms are derived from the thermal activation mechanisms that govern the plastic behaviour and quantification of relevant deformation variables. The resulting physics-based rate-dependent crystal plasticity model is implemented in a crystal plasticity finite element code. Uniaxial simulations reveal orientation-dependent tension-compression asymmetry of yield that more accurately represents single-crystal experimental results than standard models.

  12. Autoclave nuclear criticality safety analysis

    SciTech Connect

    D`Aquila, D.M.; Tayloe, R.W. Jr.

    1991-12-31

    Steam-heated autoclaves are used in gaseous diffusion uranium enrichment plants to heat large cylinders of UF{sub 6}. Nuclear criticality safety for these autoclaves is evaluated. To enhance criticality safety, systems are incorporated into the design of autoclaves to limit the amount of water present. These safety systems also increase the likelihood that any UF{sub 6} inadvertently released from a cylinder into an autoclave is not released to the environment. Up to 140 pounds of water can be held up in large autoclaves. This mass of water is sufficient to support a nuclear criticality when optimally combined with 125 pounds of UF{sub 6} enriched to 5 percent U{sup 235}. However, water in autoclaves is widely dispersed as condensed droplets and vapor, and is extremely unlikely to form a critical configuration with released UF{sub 6}.

  13. Interfacial stress in a carbon-to-metal bond joint under thermal shock loading

    SciTech Connect

    You, J.H.

    1998-02-01

    The duplex bond joint consisting of a metallic substrate armored with carbon-base materials is a promising candidate configuration for application to high heat flux operations. When a bond joint is subjected to thermal loadings, significant thermal stresses may develop due to mismatch of the thermal expansion coefficients. Stress intensification occurs near the free surface edge of the interface, sometimes showing singularity. The singular stress fields are critical for understanding the loading nature of the bond interface in a joint system. In this paper, thermal stresses in the bond interface of a carbon-to-molybdenum joint element were investigated. A high heat flux (HHF) pulse was assumed as the reference load history to simulate the thermal shock condition. The thermomechanical behavior was described quantitatively in terms of the stress intensity factor. The stress solutions of the singular field computed by the theoretical approach showed a good agreement with the numerical results of the finite element analysis. The stress intensity factor of the singular stress fields near the free surface edge of the interface showed a time variation similar to that of the bulk stress. The temperature gradient induced by the transient HHF load affected the overall interfacial stress only slightly.

  14. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas; Goyal, Vinay; Lundgren, Eric; Patel, Dhruv; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. Fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a strength reduction of 10 percent due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  15. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas; Goyal, Vinay; Lundgren, Eric; Patel, Dhruv; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and facesheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  16. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas A.; Goyal, Vinay K.; Lundgren, Eric C.; Patel, Dhruv N.; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth N.

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  17. Numerical investigations of rib fracture failure models in different dynamic loading conditions.

    PubMed

    Wang, Fang; Yang, Jikuang; Miller, Karol; Li, Guibing; Joldes, Grand R; Doyle, Barry; Wittek, Adam

    2016-01-01

    Rib fracture is one of the most common thoracic injuries in vehicle traffic accidents that can result in fatalities associated with seriously injured internal organs. A failure model is critical when modelling rib fracture to predict such injuries. Different rib failure models have been proposed in prediction of thorax injuries. However, the biofidelity of the fracture failure models when varying the loading conditions and the effects of a rib fracture failure model on prediction of thoracic injuries have been studied only to a limited extent. Therefore, this study aimed to investigate the effects of three rib failure models on prediction of thoracic injuries using a previously validated finite element model of the human thorax. The performance and biofidelity of each rib failure model were first evaluated by modelling rib responses to different loading conditions in two experimental configurations: (1) the three-point bending on the specimen taken from rib and (2) the anterior-posterior dynamic loading to an entire bony part of the rib. Furthermore, the simulation of the rib failure behaviour in the frontal impact to an entire thorax was conducted at varying velocities and the effects of the failure models were analysed with respect to the severity of rib cage damages. Simulation results demonstrated that the responses of the thorax model are similar to the general trends of the rib fracture responses reported in the experimental literature. However, they also indicated that the accuracy of the rib fracture prediction using a given failure model varies for different loading conditions. PMID:26214136

  18. Preliminary design study of lunar housing configurations

    NASA Technical Reports Server (NTRS)

    Reynolds, K. H.

    1992-01-01

    A preliminary design study assesses various configurations for habitation of the lunar surface. The study assumes an initial 4-man habitation module expandable to a 48-man concept. Through the numerous coupling combinations of identical modules, five basic configuration types are identified. A design model presents each configuration in light of certain issues. The issues include circulation, internal and external spatial characteristics, functional organizations, and future growth potential. The study discusses the attributes, potentials, and unique requirements of each configuration.

  19. Load to Failure and Stiffness

    PubMed Central

    Esquivel, Amanda O.; Duncan, Douglas D.; Dobrasevic, Nikola; Marsh, Stephanie M.; Lemos, Stephen E.

    2015-01-01

    Background: Rotator cuff tendinopathy is a frequent cause of shoulder pain that can lead to decreased strength and range of motion. Failures after using the single-row technique of rotator cuff repair have led to the development of the double-row technique, which is said to allow for more anatomical restoration of the footprint. Purpose: To compare 5 different types of suture patterns while maintaining equality in number of anchors. The hypothesis was that the Mason-Allen–crossed cruciform transosseous-equivalent technique is superior to other suture configurations while maintaining equality in suture limbs and anchors. Study Design: Controlled laboratory study. Methods: A total of 25 fresh-frozen cadaveric shoulders were randomized into 5 suture configuration groups: single-row repair with simple stitch technique; single-row repair with modified Mason-Allen technique; double-row Mason-Allen technique; double-row cross-bridge technique; and double-row suture bridge technique. Load and displacement were recorded at 100 Hz until failure. Stiffness and bone mineral density were also measured. Results: There was no significant difference in peak load at failure, stiffness, maximum displacement at failure, or mean bone mineral density among the 5 suture configuration groups (P < .05). Conclusion: According to study results, when choosing a repair technique, other factors such as number of sutures in the repair should be considered to judge the strength of the repair. Clinical Relevance: Previous in vitro studies have shown the double-row rotator cuff repair to be superior to the single-row repair; however, clinical research does not necessarily support this. This study found no difference when comparing 5 different repair methods, supporting research that suggests the number of sutures and not the pattern can affect biomechanical properties. PMID:26665053

  20. 47 CFR 22.623 - System configuration.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false System configuration. 22.623 Section 22.623... Paging and Radiotelephone Service Point-To-Multipoint Operation § 22.623 System configuration. This section requires a minimum configuration for point-to-multipoint systems using the channels listed in §...

  1. 47 CFR 22.623 - System configuration.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false System configuration. 22.623 Section 22.623... Paging and Radiotelephone Service Point-To-Multipoint Operation § 22.623 System configuration. This section requires a minimum configuration for point-to-multipoint systems using the channels listed in §...

  2. Resolvability and the Tetrahedral Configuration of Carbon.

    ERIC Educational Resources Information Center

    Kauffman, George B.

    1983-01-01

    Discusses evidence for the tetrahedral configuration of the carbon atom, indicating that three symmetrical configurations are theoretically possible for coordination number four. Includes table indicating that resolvability of compounds of type CR'R"R"'R"" is a necessary but not sufficient condition for proving tetrahedral configuration. (JN)

  3. Preliminary aerodynamic design considerations for advanced laminar flow aircraft configurations

    NASA Technical Reports Server (NTRS)

    Johnson, Joseph L., Jr.; Yip, Long P.; Jordan, Frank L., Jr.

    1986-01-01

    Modern composite manufacturing methods have provided the opportunity for smooth surfaces that can sustain large regions of natural laminar flow (NLF) boundary layer behavior and have stimulated interest in developing advanced NLF airfoils and improved aircraft designs. Some of the preliminary results obtained in exploratory research investigations on advanced aircraft configurations at the NASA Langley Research Center are discussed. Results of the initial studies have shown that the aerodynamic effects of configuration variables such as canard/wing arrangements, airfoils, and pusher-type and tractor-type propeller installations can be particularly significant at high angles of attack. Flow field interactions between aircraft components were shown to produce undesirable aerodynamic effects on a wing behind a heavily loaded canard, and the use of properly designed wing leading-edge modifications, such as a leading-edge droop, offset the undesirable aerodynamic effects by delaying wing stall and providing increased stall/spin resistance with minimum degradation of laminar flow behavior.

  4. Biaxial fatigue loading of notched composites

    NASA Technical Reports Server (NTRS)

    Francis, P. H.; Walrath, D. E.; Sims, D. F.; Weed, D. N.

    1977-01-01

    Thin-walled, 2.54-cm diameter tubular specimens of graphite/epoxy were fatigue cycled in combinations of axial, torsional, and internal pressure loading. Two different four-ply layup configurations were tested: (0-90)s and (+ or- 45)s; each tube contained a 0.48-cm diameter circular hole penetrating one wall midway along the tube length. S-N curves were developed to characterize fatigue behavior under pure axial, torsional, or internal pressure loading, as well as combined loading fatigue. A theory was developed based on a plane stress model which enabled the S-N curve for combined stress states to be predicted from the S-N data for the uniaxial loading modes. Correlation of the theory with the experimental data proved to be remarkably good.

  5. Biaxial fatigue loading of notched composites

    NASA Technical Reports Server (NTRS)

    Francis, P. H.; Walrath, D. E.; Sims, D. F.; Weed, D. N.

    1977-01-01

    Thin walled, 2.54-cm (1-in.) diameter tubular specimens of T300/934 graphite/epoxy were fabricated and fatigue cycled in combinations of axial, torsional, and internal pressure loading. Two different four-ply layup configurations were tested: (0/90)S and (+ or - 45)S; all tubes contained a 0.48-cm (3/16-in.) diameter circular hole penetrating one wall midway along the tube length. S-N curves were developed to characterize fatigue behavior under pure axial, torsional, or internal pressure loading, as well as combined loading fatigue. A theory was developed based on the Hill plane stress model which enabled the S-N curve for combined stress states to be predicted from the S-N data for the uniaxial loading modes. Correlation of the theory with the experimental data proved to be remarkably good.

  6. Loads for pulsed power cylindrical implosion experiments

    SciTech Connect

    Anderson, W.E.; Armijo, E.V.; Barthell, B.L.; Bartos, J.J.; Bush, H.; Foreman, L.R.; Garcia, F.P.; Gobby, P.L.; Gomez, V.M.; Gurule, V.A.

    1994-07-01

    Pulse power can be used to generate high energy density conditions in convergent hollow cylindrical geometry through the use of appropriate electrode configuration and cylindrical loads. Cylindrically symmetric experiments are conducted with the Pegasus-H inductive store, capacitor energized pulse power facility at Los Alamos using both precision machined cylindrical liner loads and low mass vapor deposited cylindrical foil loads. The liner experiments investigate solid density hydrodynamic topics. Foil loads vaporize from Joule heating to generate an imploding cylindrical plasma which can be used to simulate some fluxes associated with fusion energy processes. Similar experiments are conducted with {open_quotes}Procyon{close_quotes} inductive store pulse power assemblies energized by explosively driven magnetic flux compression.

  7. Plutonium immobilization -- Can loading

    SciTech Connect

    Kriikku, E.

    2000-02-17

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Project (PIP). The PIP adds the excess plutonium to ceramic pucks, loads the pucks into cans, and places the cans into DWPF canisters. This paper discusses the PIP process steps, the can loading conceptual design, can loading equipment design, and can loading work completed.

  8. Reactor Configuration Development for ARIES-CS

    SciTech Connect

    Ku LP, the ARIES-CS Team

    2005-09-27

    New compact, quasi-axially symmetric stellarator configurations have been developed as part of the ARIES-CS reactor studies. These new configurations have good plasma confinement and transport properties, including low losses of α particles and good integrity of flux surfaces at high β. We summarize the recent progress by showcasing two attractive classes of configurationsconfigurations with judiciously chosen rotational transforms to avoid undesirable effects of low order resonances on the flux surface integrity and configurations with very small aspect ratios (∼2.5) that have excellent quasi-axisymmetry and low field ripples.

  9. Stable molecular configuration in crystalline carboxylic acids

    NASA Astrophysics Data System (ADS)

    Hayashi, Soichi; Umemura, Junzo; Nakamura, Ryoko

    1980-12-01

    The stable (lower enthalpy) molecular configurations of propionic, butyric, Jeric and lauric acids in the crystalline state have been examined via their atom-atom potentials. It was found that the cis configuration is more stable than the trans configuration for propionic, butyric and valeric acids, and that the trans configuration is more stable than the cis configuration for lauric acid, in accord with a previous IR spectral analysis. The potential energy of benzoic acid was recalculated using the positions of atoms given by Speakman, and indicates that the A form is more stable than the B form, in agreement with the results of previous work.

  10. Analysis of surface pressure distributions on two elliptic missile configurations

    NASA Technical Reports Server (NTRS)

    Allen, J. M.; Pittman, J. L.

    1983-01-01

    The state-of-the-art methods for predicting missile aerodynamic characteristics do not accurately predict the loads of missile configurations with bodies of elliptic cross section. An investigation of this problem found significant nonlinear flow disturbance on the windward surface of a 3:1 elliptic body at Mach 2.50 in addition to the nonlinear vortical flows which develop on the leeside. A nonlinear full-potential flow method (NCOREL) was found to provide extremely accurate pressure estimates for attached-flow conditions and the vortex prediction method contained in the state-of-the-art method (NOSEVTX) was shown to accurately calculate body vortices and leeside pressures.

  11. Wind-tunnel roll-damping measurements of a winged space shuttle configuration in launch attitude

    NASA Technical Reports Server (NTRS)

    Hess, R. W.; Davenport, E. E.

    1973-01-01

    Ground-wind load studies were conducted on three model configurations to assess the importance of aeroelastic instabilities of erected space shuttle vehicles. Roll damping was measured on a fuselage-alone model, which had a D cross section, and a fuselage and tail surfaces in combination with either a clipped-delta wing or a low-sweep tapered wing as the primary lifting surface. The largest negative roll-damping coefficients were measured with the fuselage-alone configuration and were a function of wind azimuth. At the wind azimuths at which the wing-fuselage configuration was unstable, the negative roll-damping coefficients were a function of reduced frequency.

  12. Systems and methods for providing power to a load based upon a control strategy

    DOEpatents

    Perisic, Milun; Kajouke, Lateef A; Ransom, Ray M

    2013-12-24

    Systems and methods are provided for an electrical system. The electrical system includes a load, an interface configured to receive a voltage from a voltage source, and a controller configured to receive the voltage from the voltage source through the interface and to provide a voltage and current to the load. Wherein, when the controller is in a constant voltage mode, the controller provides a constant voltage to the load, when the controller is in a constant current mode, the controller provides a constant current to the load, and when the controller is in a constant power mode, the controller provides a constant power to the load.

  13. Intelligent electrical outlet for collective load control

    SciTech Connect

    Lentine, Anthony L.; Ford, Justin R.; Spires, Shannon V.; Goldsmith, Steven Y.

    2015-10-27

    Various technologies described herein pertain to an electrical outlet that autonomously manages loads in a microgrid. The electrical outlet can provide autonomous load control in response to variations in electrical power generation supply in the microgrid. The electrical outlet includes a receptacle, a sensor operably coupled to the receptacle, and an actuator configured to selectively actuate the receptacle. The sensor measures electrical parameters at the receptacle. Further, a processor autonomously controls the actuator based at least in part on the electrical parameters measured at the receptacle, electrical parameters from one or more disparate electrical outlets in the microgrid, and a supply of generated electric power in the microgrid at a given time.

  14. Structural load challenges during space shuttle development

    NASA Technical Reports Server (NTRS)

    Mackey, A. C.; Gatto, R. E.

    1985-01-01

    The challenges that resulted from the unique configuration of the space shuttle and capabilities developed to meet these challenges are described. The methods and the organization that were developed to perform dynamic loads analyses on the space shuttle configuration and to assess dynamic data developed after design are discussed. Examples are presented from the dynamic loads analysis of the lift-off and maximum dynamic pressure portion of ascent. Also shown are orbital flight test results, for which selected predicted responses are compared to measured data for the lift-off and high-dynamic-pressure times of ascent. These results have generally verified the design analysis. However, subscale testing was found to be deficient in predicting full-scale results in two areas: the ignition overpressure at lift-off and the aerodynamics/plume interactions at high-q boost. In these areas, the results of the flight test program were accommodated with no impact to the vehicle design.

  15. Configurational forces in solid nanostructures

    SciTech Connect

    Zhigang Suo

    2006-06-12

    The DOE grant (DE-FG02-99ER45787) to Princeton University, entitled Configurational Forces in Solid Nanostructures, was intended to cover the four-year period from September 1999 to September 2003. Effective 1 July 2003, the PI will relocate from Princeton to join the Harvard faculty. Princeton University will submit the Final Financial Report, the Final Property Report, and the Final Patent Report. The expenditures to date are $261,513 with %8,487 remaining of the awarded amount of $320,000. Harvard University will submit a request for the remaining amount. This Final Technical Report covers from the period between September 1999 to June 2003. Three Ph.D. students, Wei Lu, Yanfei Gao and Wei Hong, admitted to Princeton in the fall of 1998, 1999, 2002, respectively, have been dedicated to this project. Wei Lu earned his Ph.D. in August 2001, and is now an assistant professor at The University of Michigan, Ann Arbor. Yanfei Gao earned his Ph.D. in February 2003, and is now a post-doc at Brown University. The amount of funding covers one student at a time. All three students received first-year fellowships from Princeton University. In the Mechanical and Aerospace Engineering Department, to fulfill a doctoral degree requirement, every student serves as a teaching assistant for three semesters, for which the student is partially paid by the University.

  16. High Performance Field Reversed Configurations

    NASA Astrophysics Data System (ADS)

    Binderbauer, Michl

    2014-10-01

    The field-reversed configuration (FRC) is a prolate compact toroid with poloidal magnetic fields. FRCs could lead to economic fusion reactors with high power density, simple geometry, natural divertor, ease of translation, and possibly capable of burning aneutronic fuels. However, as in other high-beta plasmas, there are stability and confinement concerns. These concerns can be addressed by introducing and maintaining a significant fast ion population in the system. This is the approach adopted by TAE and implemented for the first time in the C-2 device. Studying the physics of FRCs driven by Neutral Beam (NB) injection, significant improvements were made in confinement and stability. Early C-2 discharges had relatively good confinement, but global power losses exceeded the available NB input power. The addition of axially streaming plasma guns, magnetic end plugs as well as advanced surface conditioning leads to dramatic reductions in turbulence driven losses and greatly improved stability. As a result, fast ion confinement significantly improved and allowed for build-up of a dominant fast particle population. Under such appropriate conditions we achieved highly reproducible, long-lived, macroscopically stable FRCs with record lifetimes. This demonstrated many beneficial effects of large orbit particles and their performance impact on FRCs Together these achievements point to the prospect of beam-driven FRCs as a path toward fusion reactors. This presentation will review and expand on key results and present context for their interpretation.

  17. Space Station-Baseline Configuration

    NASA Technical Reports Server (NTRS)

    1989-01-01

    In response to President Reagan's directive to NASA to develop a permanent marned Space Station within a decade, part of the State of the Union message to Congress on January 25, 1984, NASA and the Administration adopted a phased approach to Station development. This approach provided an initial capability at reduced costs, to be followed by an enhanced Space Station capability in the future. This illustration depicts the baseline configuration, which features a 110-meter-long horizontal boom with four pressurized modules attached in the middle. Located at each end are four photovoltaic arrays generating a total of 75-kW of power. Two attachment points for external payloads are provided along this boom. The four pressurized modules include the following: A laboratory and habitation module provided by the United States; two additional laboratories, one each provided by the European Space Agency (ESA) and Japan; and an ESA-provided Man-Tended Free Flyer, a pressurized module capable of operations both attached to and separate from the Space Station core. Canada was expected to provide the first increment of a Mobile Serving System.

  18. Skylab Components in Launch Configuration

    NASA Technical Reports Server (NTRS)

    1969-01-01

    This cutaway drawing illustrates major Skylab components in launch configuration on top of the Saturn V. In an early effort to extend the use of Apollo for further applications, NASA established the Apollo Applications Program (AAP) in August of 1965. The AAP was to include long duration Earth orbital missions during which astronauts would carry out scientific, technological, and engineering experiments in space by utilizing modified Saturn launch vehicles and the Apollo spacecraft. Established in 1970, the Skylab Program was the forerurner of the AAP. The goals of the Skylab were to enrich our scientific knowledge of the Earth, the Sun, the stars, and cosmic space; to study the effects of weightlessness on living organisms, including man; to study the effects of the processing and manufacturing of materials utilizing the absence of gravity; and to conduct Earth resource observations. The Skylab also conducted 19 selected experiments submitted by high school students. Skylab's 3 different 3-man crews spent up to 84 days in Earth orbit. The Marshall Space Flight Center (MSFC) had responsibility for developing and integrating most of the major components of the Skylab: the Orbital Workshop (OWS), Airlock Module (AM), Multiple Docking Adapter (MDA), Apollo Telescope Mount (ATM), Payload Shroud (PS), and most of the experiments. MSFC was also responsible for providing the Saturn IB launch vehicles for three Apollo spacecraft and crews and a Saturn V launch vehicle for the Skylab.

  19. RCA direct broadcast satellite configuration

    NASA Astrophysics Data System (ADS)

    Miller, R.; Buntschuh, R. F.

    System requirements and the spacecraft configuration for a DBS mission in 1986, contracted by RCA Americom, are presented. Performance features are to include a dc power of 315 W, a stationkeeping accuracy of up to 0.1 deg, a pointing accuracy of up to 0.05 deg, and continental U.S. coverage. Four on-orbit operating satellites are needed, each weighing at least 1100 kg, having antennas of about 3 m diam, six RF channels, and no eclipse operating requirements. Three-axis stabilization, a pivoted momentum wheel, hydrazine thrusters, a bipropellant liquid perigee stage, a solid apogee kick motor, Ni-Cd batteries, 230 W power amplifiers, and launch compatibility with the STS. The spacecraft length will be approximately 23 m with solar panels deployed. Feedhorns will be used on for transmissions and a switching network will be installed to optimize time zone coverage. Each spacecraft will generate over 1.38 kW of on-board RF power.

  20. Breast tomosynthesis imaging configuration analysis.

    PubMed

    Rayford, Cleveland E; Zhou, Weihua; Chen, Ying

    2013-01-01

    Traditional two-dimensional (2D) X-ray mammography is the most commonly used method for breast cancer diagnosis. Recently, a three-dimensional (3D) Digital Breast Tomosynthesis (DBT) system has been invented, which is likely to challenge the current mammography technology. The DBT system provides stunning 3D information, giving physicians increased detail of anatomical information, while reducing the chance of false negative screening. In this research, two reconstruction algorithms, Back Projection (BP) and Shift-And-Add (SAA), were used to investigate and compare View Angle (VA) and the number of projection images (N) with parallel imaging configurations. In addition, in order to better determine which method displayed better-quality imaging, Modulation Transfer Function (MTF) analyses were conducted with both algorithms, ultimately producing results which improve upon better breast cancer detection. Research studies find evidence that early detection of the disease is the best way to conquer breast cancer, and earlier detection results in the increase of life span for the affected person. PMID:23900440

  1. High Power Disk Loaded Guide Load

    SciTech Connect

    Farkas, Z.D.; /SLAC

    2006-02-22

    A method to design a matching section from a smooth guide to a disk-loaded guide, using a variation of broadband matching, [1, 2] is described. Using this method, we show how to design high power loads. The load consists of a disk-loaded coaxial guide operating in the TE{sub 01}-mode. We use this mode because it has no electric field terminating on a conductor, has no axial currents, and has no current at the cylinder-disk interface. A high power load design that has -35 dB reflection and a 200 MHz, -20 dB bandwidth, is presented. It is expected that it will carry the 600 MW output peak power of the pulse compression network. We use coaxial geometry and stainless steel material to increase the attenuation per cell.

  2. Criticality assessment of LLRWDF closure

    SciTech Connect

    Sarrack, A.G.; Weber, J.H.; Woody, N.D.

    1992-10-06

    During the operation of the Low Level Radioactive Waste Disposal Facility (LLRWDF), large amounts (greater than 100 kg) of enriched uranium (EU) were buried. This EU came primarily from the closing and decontamination of the Naval Fuels Facility in the time period from 1987--1989. Waste Management Operations (WMO) procedures were used to keep the EU boxes separated to prevent possible criticality during normal operation. Closure of the LLRWDF is currently being planned, and waste stabilization by Dynamic Compaction (DC) is proposed. Dynamic compaction will crush the containers in the LLRWDF and result in changes in their geometry. Research of the LLRWDF operations and record keeping practices have shown that the EU contents of trenches are known, but details of the arrangement of the contents cannot be proven. Reviews of the trench contents, combined with analysis of potential critical configurations, revealed that some portions of the LLRWDF can be expected to be free of criticality concerns while other sections have credible probabilities for the assembly of a critical mass, even in the uncompacted configuration. This will have an impact on the closure options and which trenches can be compacted.

  3. Combined mechanical loading of composite tubes

    NASA Technical Reports Server (NTRS)

    Derstine, Mark S.; Pindera, Marek-Jerzy; Bowles, David E.

    1988-01-01

    An analytical/experimental investigation was performed to study the effect of material nonlinearities on the response of composite tubes subjected to combined axial and torsional loading. The effect of residual stresses on subsequent mechanical response was included in the investigation. Experiments were performed on P75/934 graphite-epoxy tubes with a stacking sequence of (15/0/ + or - 10/0/ -15), using pure torsion and combined axial/torsional loading. In the presence of residual stresses, the analytical model predicted a reduction in the initial shear modulus. Experimentally, coupling between axial loading and shear strain was observed in laminated tubes under combined loading. The phenomenon was predicted by the nonlinear analytical model. The experimentally observed linear limit of the global shear response was found to correspond to the analytically predicted first ply failure. Further, the failure of the tubes was found to be path dependent above a critical load level.

  4. Optimization of baffle configuration for stray light reduction

    NASA Astrophysics Data System (ADS)

    Pancrazzi, M.; Vivès, S.; Landini, F.; Guillon, C.; Escolle, C.; Garcia, J.

    2013-09-01

    Reducing the stray light level is one of the issues that astronomical instruments have to face. In particular, the design of baffles requires special attention in order to minimize the light scattered and diffracted by the edge of the baffle's vanes. The choice of the materials and the treatments used to manufacturing those parts can significantly increase the performance of stray light suppression. This is particularly critical for instruments in which the main source of stray light is in the field-of-view and its brightness is much higher than the signal the experiment aims to measure, such as solar and stellar coronagraphs. In order to identify the best configuration to adopt in the design and manufacture of a future coronagraph, we designed a dedicated set-up that allows comparing different edge geometries and finishing in a fast and comprehensive approach. A reference edge configuration was chosen and all the other configurations were compared with it. In this paper, we describe the set-up, the characterized configurations and the obtained results.

  5. High speed research system study. Advanced flight deck configuration effects

    NASA Technical Reports Server (NTRS)

    Swink, Jay R.; Goins, Richard T.

    1992-01-01

    In mid-1991 NASA contracted with industry to study the high-speed civil transport (HSCT) flight deck challenges and assess the benefits, prior to initiating their High Speed Research Program (HSRP) Phase 2 efforts, then scheduled for FY-93. The results of this nine-month effort are presented, and a number of the most significant findings for the specified advanced concepts are highlighted: (1) a no nose-droop configuration; (2) a far forward cockpit location; and (3) advanced crew monitoring and control of complex systems. The results indicate that the no nose-droop configuration is critically dependent upon the design and development of a safe, reliable, and certifiable Synthetic Vision System (SVS). The droop-nose configuration would cause significant weight, performance, and cost penalties. The far forward cockpit location, with the conventional side-by-side seating provides little economic advantage; however, a configuration with a tandem seating arrangement provides a substantial increase in either additional payload (i.e., passengers) or potential downsizing of the vehicle with resulting increases in performance efficiencies and associated reductions in emissions. Without a droop nose, forward external visibility is negated and takeoff/landing guidance and control must rely on the use of the SVS. The technologies enabling such capabilities, which de facto provides for Category 3 all-weather operations on every flight independent of weather, represent a dramatic benefits multiplier in a 2005 global ATM network: both in terms of enhanced economic viability and environmental acceptability.

  6. Lexical Configuration and Lexical Engagement: When Adults Learn New Words

    PubMed Central

    Leach, Laura; Samuel, Arthur G.

    2007-01-01

    People know thousands of words in their native language, and each of these words must be learned at some time in the person's lifetime. A large number of these words will be learned when the person is an adult, reflecting the fact that the mental lexicon is continuously changing. We explore how new words get added to the mental lexicon, and provide empirical support for a theoretical distinction between what we call lexical configuration and lexical engagement. Lexical configuration is the set of factual knowledge associated with a word (e.g., the word's sound, spelling, meaning, or syntactic role). Almost all previous research on word learning has focused on this aspect. However it is also critical to understand the process by which a word becomes capable of lexical engagement – the ways in which a lexical entry dynamically interacts with other lexical entries, and with sublexical representations. For example, lexical entries compete with each other during word recognition (inhibition within the lexical level), and they also support the activation of their constituents (top-down lexical-phonemic facilitation, and lexically-based perceptual learning). We systematically vary the learning conditions for new words, and use separate measures of lexical configuration and engagement. Several surprising dissociations in behavior demonstrate the importance of the theoretical distinction between configuration and engagement. PMID:17367775

  7. Configurable Middleware-Level Intrusion Detection for Embedded Systems

    SciTech Connect

    Naess, Eivind; Frincke, Deborah A.; McKinnon, A. D.; Bakken, David E.

    2005-06-20

    Embedded systems have become integral parts of a diverse range of systems from automobiles to critical infrastructure applications such as gas and electric power distribution. Unfortunately, research on computer security in general and intrusion detection in particular, has not kept pace. Furthermore, embedded systems, by their very nature, are application specific and therefore frameworks for developing application-specific intrusion detection systems for distributed embedded systems must be researched, designed, and implemented. In this paper, we present a configurable middleware-based intrusion detection framework. In particular, this paper presents a system model and a concrete implementation of a highly configurable intrusion detection framework that is integrated into MicroQoSCORBA, a highly configurable middleware framework developed for embedded systems. By exploiting the application-specific logic available to a middleware framework (e.g., object interfaces and method signatures), our integrated framework is able to autogenerate application-specific intrusion detection systems. Next, a set of configurable intrusion detection mechanisms suitable for embedded systems is presented. A performance evaluation of these mechanisms, run on two hardware platforms, is presented at the end of the paper.

  8. Stability Of Plasma Configurations During Compression

    SciTech Connect

    Ruden, E L; Hammer, J H

    2006-10-27

    quasispherical (3-D) compression otherwise. Use of a Field Reversed Configuration (FRC) substantially resolves the wall contact issue, but at the cost of introducing a new (rotational) instability. An FRC has an open magnetic field outside a separatrix which effectively diverts wall material. However, FRC particles diffusing across the separatrix have a preferred angular momentum, causing the FRC within to counter-rotate in response. When the FRC's rotational-diamagnetic drift frequency ratio {alpha} reaches a critical value of order unity, the FRC undergoes a rotational instability that results in rapid particle loss. The instability is exacerbated by cylindrical compression since {beta} {approx} R{sup -2/5} during this phase, assuming angular momentum conservation. A multipole magnetic field frozen into the solid liner during compression may stabilize this mode directly and/or by impeding spin-up without significantly perturbing the implosion's azimuthal symmetry.

  9. Modeling and Simulation of a Helicopter Slung Load Stabilization Device

    NASA Technical Reports Server (NTRS)

    Cicolani, Luigi S.; Ehlers, George E.

    2002-01-01

    This paper addresses the problem of simulation and stabilization of the yaw motions of a cargo container slung load. The study configuration is a UH-60 helicopter carrying a 6ft x 6 ft x 8 ft CONEX container. This load is limited to 60 KIAS in operations and flight testing indicates that it starts spinning in hover and that spin rate increases with airspeed. The simulation reproduced the load yaw motions seen in the flight data after augmenting the load model with terms representing unsteady load yaw moment effects acting to reinforce load oscillations, and augmenting the hook model to include yaw resistance at the hook. The use of a vertical fin to stabilize the load is considered. Results indicate that the CONEX airspeed can be extended to 110 kts using a 3x5 ft fin.

  10. Metrics for measuring distances in configuration spaces.

    PubMed

    Sadeghi, Ali; Ghasemi, S Alireza; Schaefer, Bastian; Mohr, Stephan; Lill, Markus A; Goedecker, Stefan

    2013-11-14

    In order to characterize molecular structures we introduce configurational fingerprint vectors which are counterparts of quantities used experimentally to identify structures. The Euclidean distance between the configurational fingerprint vectors satisfies the properties of a metric and can therefore safely be used to measure dissimilarities between configurations in the high dimensional configuration space. In particular we show that these metrics are a perfect and computationally cheap replacement for the root-mean-square distance (RMSD) when one has to decide whether two noise contaminated configurations are identical or not. We introduce a Monte Carlo approach to obtain the global minimum of the RMSD between configurations, which is obtained from a global minimization over all translations, rotations, and permutations of atomic indices. PMID:24320265

  11. Metrics for measuring distances in configuration spaces

    SciTech Connect

    Sadeghi, Ali Ghasemi, S. Alireza; Schaefer, Bastian; Mohr, Stephan; Goedecker, Stefan; Lill, Markus A.

    2013-11-14

    In order to characterize molecular structures we introduce configurational fingerprint vectors which are counterparts of quantities used experimentally to identify structures. The Euclidean distance between the configurational fingerprint vectors satisfies the properties of a metric and can therefore safely be used to measure dissimilarities between configurations in the high dimensional configuration space. In particular we show that these metrics are a perfect and computationally cheap replacement for the root-mean-square distance (RMSD) when one has to decide whether two noise contaminated configurations are identical or not. We introduce a Monte Carlo approach to obtain the global minimum of the RMSD between configurations, which is obtained from a global minimization over all translations, rotations, and permutations of atomic indices.

  12. Integrative application of active controls (IAAC) technology to an advanced subsonic transport project. Initial act configuration design study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The performance and economic benefits of a constrained application of Active Controls Technology (ACT) are identified, and the approach to airplane design is established for subsequent steps leading to the development of a less constrained final ACT configuration. The active controls configurations are measured against a conventional baseline configuration, a state-of-the-art transport, to determine whether the performance and economic changes resulting from ACT merit proceeding with the project. The technology established by the conventional baseline configuration was held constant except for the addition of ACT. The wing, with the same planform, was moved forward on the initial ACT configuration to move the loading range aft relative to the wing mean aerodynamic chord. Wing trailing-edge surfaces and surface controls also were reconfigured for load alleviation and structural stabilization.

  13. Estimating the Configuration of a Continuum Dexterous Manipulator with Variable Curvature Bending Using Partial Shape-Sensing

    PubMed Central

    Murphy, Ryan J.; Armand, Mehran

    2016-01-01

    Reliably estimating the shape of variable curvature continuum dexterous manipulators (CDMs) is necessary to use these devices in biomedical applications. Embedding shape-sensing elements have been shown to effectively measure the shape of constant curvature CDMs. This paper explores several methods for estimating the configuration of variable curvature CDMs. Experiments bent the CDM in varying configurations, applied an external load, and measured the configuration. Three methods are described that use the measurements from simulated shape-sensing elements. Analyses included varying the number and placement of the shape sensors. The results showed at least three shape-sensing elements are necessary to predict manipulator configuration, with one method demonstrating average error less than 0.35 mm for a CDM under an external load. The presented techniques offer promise for successfully predicting, tracking, and controlling CDM configuration during surgery. PMID:26737480

  14. Parasitic load control system for exhaust temperature control

    DOEpatents

    Strauser, Aaron D.; Coleman, Gerald N.; Coldren, Dana R.

    2009-04-28

    A parasitic load control system is provided. The system may include an exhaust producing engine and a fuel pumping mechanism configured to pressurize fuel in a pressure chamber. The system may also include an injection valve configured to cause fuel pressure to build within the pressure chamber when in a first position and allow injection of fuel from the pressure chamber into one or more combustion chambers of the engine when in a second position. The system may further include a controller configured to independently regulate the pressure in the pressure chamber and the injection of fuel into the one or more combustion chambers, to increase a load on the fuel pumping mechanism, increasing parasitic load on the engine, thereby increasing a temperature of the exhaust produced by the engine.

  15. Analytical stress intensity solution for the Stable Poisson Loaded specimen

    NASA Astrophysics Data System (ADS)

    Ghosn, Louis J.; Calomino, Anthony M.; Brewer, David N.

    1993-04-01

    An analytical calibration of the Stable Poisson Loaded (SPL) specimen is presented. The specimen configuration is similar to the ASTM E-561 compact-tension specimen with displacement controlled wedge loading used for R-curve determination. The crack mouth opening displacements (CMODs) are produced by the diametral expansion of an axially compressed cylindrical pin located in the wake of a machined notch. Due to the unusual loading configuration, a three-dimensional finite element analysis was performed with gap elements simulating the contact between the pin and specimen. In this report, stress intensity factors, CMODs, and crack displacement profiles, are reported for different crack lengths and different contacting conditions. It was concluded that the computed stress intensity factor decreases sharply with increasing crack length thus making the SPL specimen configuration attractive for fracture testing of brittle, high modulus materials.

  16. Numerical calibration of the stable poisson loaded specimen

    NASA Astrophysics Data System (ADS)

    Ghosn, Louis J.; Calomino, Anthony M.; Brewer, Dave N.

    1992-10-01

    An analytical calibration of the Stable Poisson Loaded (SPL) specimen is presented. The specimen configuration is similar to the ASTM E-561 compact-tension specimen with displacement controlled wedge loading used for R-Curve determination. The crack mouth opening displacements (CMOD's) are produced by the diametral expansion of an axially compressed cylindrical pin located in the wake of a machined notch. Due to the unusual loading configuration, a three-dimensional finite element analysis was performed with gap elements simulating the contact between the pin and specimen. In this report, stress intensity factors, CMOD's, and crack displacement profiles are reported for different crack lengths and different contacting conditions. It was concluded that the computed stress intensity factor decreases sharply with increasing crack length, thus making the SPL specimen configuration attractive for fracture testing of brittle, high modulus materials.

  17. Analytical stress intensity solution for the stable Poisson loaded specimen

    NASA Astrophysics Data System (ADS)

    Ghosn, Louis J.; Calomino, Anthony M.; Brewer, David N.

    1993-04-01

    An analytical calibration of the Stable Poisson Loaded (SPL) specimen is presented. The specimen configuration is similar to the ASTM E-561 compact-tension specimen with displacement controlled wedge loading used for R-curve determination. The crack mouth opening displacements (CMOD's) are produced by the diametral expansion of an axially compressed cylindrical pin located in the wake of a machined notch. Due to the unusual loading configuration, a three-dimensional finite element analysis was performed with gap elements simulating the contact between the pin and specimen. In this report, stress intensity factors, CMOD's, and crack displacement profiles, are reported for different crack lengths and different contacting conditions. It was concluded that the computed stress intensity factor decreases sharply with increasing crack length thus making the SPL specimen configuration attractive for fracture testing of brittle, high modulus materials.

  18. Numerical calibration of the stable poisson loaded specimen

    NASA Technical Reports Server (NTRS)

    Ghosn, Louis J.; Calomino, Anthony M.; Brewer, Dave N.

    1992-01-01

    An analytical calibration of the Stable Poisson Loaded (SPL) specimen is presented. The specimen configuration is similar to the ASTM E-561 compact-tension specimen with displacement controlled wedge loading used for R-Curve determination. The crack mouth opening displacements (CMOD's) are produced by the diametral expansion of an axially compressed cylindrical pin located in the wake of a machined notch. Due to the unusual loading configuration, a three-dimensional finite element analysis was performed with gap elements simulating the contact between the pin and specimen. In this report, stress intensity factors, CMOD's, and crack displacement profiles are reported for different crack lengths and different contacting conditions. It was concluded that the computed stress intensity factor decreases sharply with increasing crack length, thus making the SPL specimen configuration attractive for fracture testing of brittle, high modulus materials.

  19. Configuration management: Phase II implementation guidance

    SciTech Connect

    Not Available

    1994-03-01

    Configuration management (CM) is essential to maintaining an acceptable level of risk to the public, workers, environment, or mission success. It is a set of activities and techniques used to maintain consistency among physical and functional configuration, applicable requirements, and key documents. This document provides guidance for continuing the implementation of CM in a phased and graded manner. It describes a cost-effective approach to documented consistency with requirements, with early emphasis on items most important to safety and environmental protection. It is intended to help responsible line managers and configuration management staff personnel in meeting the Energy Systems configuration management policy standard.

  20. The Database Driven ATLAS Trigger Configuration System

    NASA Astrophysics Data System (ADS)

    Chavez, Carlos; Gianelli, Michele; Martyniuk, Alex; Stelzer, Joerg; Stockton, Mark; Vazquez, Will

    2015-12-01

    The ATLAS trigger configuration system uses a centrally provided relational database to store the configurations for all levels of the ATLAS trigger system. The configuration used at any point during data taking is maintained in this database. A interface to this database is provided by the TriggerTool, a Java-based graphical user interface. The TriggerTool has been designed to work as both a convenient browser and editor of configurations in the database for both general users and experts. The updates to the trigger system necessitated by the upgrades and changes in both hardware and software during the first long shut down of the LHC will be explored.

  1. International Space Station Configuration Analysis and Integration

    NASA Technical Reports Server (NTRS)

    Anchondo, Rebekah

    2016-01-01

    Ambitious engineering projects, such as NASA's International Space Station (ISS), require dependable modeling, analysis, visualization, and robotics to ensure that complex mission strategies are carried out cost effectively, sustainably, and safely. Learn how Booz Allen Hamilton's Modeling, Analysis, Visualization, and Robotics Integration Center (MAVRIC) team performs engineering analysis of the ISS Configuration based primarily on the use of 3D CAD models. To support mission planning and execution, the team tracks the configuration of ISS and maintains configuration requirements to ensure operational goals are met. The MAVRIC team performs multi-disciplinary integration and trade studies to ensure future configurations meet stakeholder needs.

  2. Peltier Current Leads with conical configuration

    NASA Astrophysics Data System (ADS)

    Hakimi, I.; Nikulshin, Y.; Wolfus, S.; Yeshurun, Y.

    2016-04-01

    Current leads in cryogenic systems are a major heat source which eventually affects the entire system. It has been shown in recent years that Peltier elements are useful in reducing incoming heat into the cold system. In this article we present a new tapered cone-like configuration of the Peltier Current Leads which increases the power saving. This configuration is compared to the standard cylindrical configuration utilizing advanced ANSYS simulations. The simulations show an additional power saving of 4% when using the tapered lead configuration.

  3. Load sensing system

    DOEpatents

    Sohns, Carl W.; Nodine, Robert N.; Wallace, Steven Allen

    1999-01-01

    A load sensing system inexpensively monitors the weight and temperature of stored nuclear material for long periods of time in widely variable environments. The system can include an electrostatic load cell that encodes weight and temperature into a digital signal which is sent to a remote monitor via a coaxial cable. The same cable is used to supply the load cell with power. When multiple load cells are used, vast

  4. Configurable Multi-Purpose Processor

    NASA Technical Reports Server (NTRS)

    Valencia, J. Emilio; Forney, Chirstopher; Morrison, Robert; Birr, Richard

    2010-01-01

    Advancements in technology have allowed the miniaturization of systems used in aerospace vehicles. This technology is driven by the need for next-generation systems that provide reliable, responsive, and cost-effective range operations while providing increased capabilities such as simultaneous mission support, increased launch trajectories, improved launch, and landing opportunities, etc. Leveraging the newest technologies, the command and telemetry processor (CTP) concept provides for a compact, flexible, and integrated solution for flight command and telemetry systems and range systems. The CTP is a relatively small circuit board that serves as a processing platform for high dynamic, high vibration environments. The CTP can be reconfigured and reprogrammed, allowing it to be adapted for many different applications. The design is centered around a configurable field-programmable gate array (FPGA) device that contains numerous logic cells that can be used to implement traditional integrated circuits. The FPGA contains two PowerPC processors running the Vx-Works real-time operating system and are used to execute software programs specific to each application. The CTP was designed and developed specifically to provide telemetry functions; namely, the command processing, telemetry processing, and GPS metric tracking of a flight vehicle. However, it can be used as a general-purpose processor board to perform numerous functions implemented in either hardware or software using the FPGA s processors and/or logic cells. Functionally, the CTP was designed for range safety applications where it would ultimately become part of a vehicle s flight termination system. Consequently, the major functions of the CTP are to perform the forward link command processing, GPS metric tracking, return link telemetry data processing, error detection and correction, data encryption/ decryption, and initiate flight termination action commands. Also, the CTP had to be designed to survive and

  5. Taking a Load Off.

    ERIC Educational Resources Information Center

    Kenny, John

    1995-01-01

    Discusses the snow -load capacity of school roofs and how understanding this data aids in planning preventive measures and easing fear of roof collapse. Describes how to determine snow-load capacity, and explains the load-bearing behavior of flat versus sloped roofs. Collapse prevention measures are highlighted. (GR)

  6. Ship resistance of quadramaran with various hull position configurations

    NASA Astrophysics Data System (ADS)

    Yanuar; Gunawan; Muhyi, A.; Jamaluddin, A.

    2016-03-01

    Multihull ships are widely used for sea transportation, and those with four hulls are known as quadramarans. Hull position configurations of a quadramaran include the diamond, tetra, and slice. In general, multihull vessels traveling at high speeds have better hydrodynamic efficiency than monohull ships. This study aims to identify possible effects of various quadramaran hull position configurations on ship resistance for hull dimensions of 2 m length, 0.21 m breadth, and 0.045 m thickness. We conducted a towing test in which we varied the hull spacing and speed at Fr values between 0.08 and 0.62 and measured the total resistance using a load cell transducer. The experimental results reveal that the lowest total resistance was achieved with a diamond quadramaran configuration at Fr = 0.1-0.6 and an effective interference factor of up to 0.35 with S/L = 3/10 and R/L = 1/2 at Fr = 0.62.

  7. Effect of Configuration Pitching Motion on Twin Tail Buffet Response

    NASA Technical Reports Server (NTRS)

    Sheta, Essam F.; Kandil, Osama A.

    1998-01-01

    The effect of dynamic pitch-up motion of delta wing on twin-tail buffet response is investigated. The computational model consists of a delta wing-twin tail configuration. The computations are carried out on a dynamic multi-block grid structure. This multidisciplinary problem is solved using three sets of equations which consists of the unsteady Navier-Stokes equations, the aeroelastic equations, and the grid displacement equations. The configuration is pitched-up from zero up to 60 deg. angle of attack, and the freestream Mach number and Reynolds number are 0.3 and 1.25 million, respectively. With the twin tail fixed as rigid surfaces and with no-forced pitch-up motion, the problem is solved for the initial flow conditions. Next, the problem is solved for the twin-tail response for uncoupled bending and torsional vibrations due to the unsteady loads on the twin tail and due to the forced pitch-up motion. The dynamic pitch-up problem is also solved for the flow response with the twin tail kept rigid. The configuration is investigated for inboard position of the twin tail which corresponds to a separation distance between the twin tail of 33% wing chord. The computed results are compared with the available experimental data.

  8. Resistance analysis of unsymmetrical trimaran model with outboard sidehulls configuration

    NASA Astrophysics Data System (ADS)

    Yanuar; Gunawan; Talahatu, M. A.; Indrawati, Ragil T.; Jamaluddin, A.

    2013-09-01

    The application of multi-hull ship or trimaran vessel as a mode of transports in both river and sea environments have grown rapidly in recent years. Trimaran vessels are currently of interest for many new high speed ship projects due to the high levels of hydrodynamic efficiency that can be achieved, compared to the mono-hull and catamaran hull forms. The purpose of this study is to identify the possible effects of using an unsymmetrical trimaran ship model with configuration ( S/ L) 0.1-0.3 and R/ L=0.1-0.2. Unsymmetrical trimaran ship model with main dimensions: L=2000mm, B=200 mm and T=45 mm. Experimental methods (towing tank) were performed in the study using speed variations at Froude number 0.1-0.6. The ship model was pulled by an electric motor whose speed could be varied and adjusted. The ship model resistance was measured precisely by using a load cell transducer. The comparison of ship resistance for each configuration with mono-hull was shown on the graph as a function of the total resistance coefficient and Froude number. The test results found that the effective drag reduction could be achieved up to 17% at Fr=0.35 with configuration S/ L=0.1.

  9. Structural Configuration Analysis of Crew Exploration Vehicle Concepts

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, V.

    2006-01-01

    Structural configuration modeling and finite element analysis of crew exploration vehicle (CEV) concepts are presented. In the structural configuration design approach, parametric solid models of the pressurized shell and tanks are developed. The CEV internal cabin pressure is same as in the International Space Station (ISS) to enable docking with the ISS without an intermediate airlock. Effects of this internal pressure load on the stress distribution, factor of safety, mass and deflections are investigated. Uniform 7 mm thick skin shell, 5 mm thick shell with ribs and frames, and isogrid skin construction options are investigated. From this limited study, the isogrid construction appears to provide most strength/mass ratio. Initial finite element analysis results on the service module tanks are also presented. These rapid finite element analyses, stress and factor of safety distribution results are presented as a part of lessons learned and to build up a structural mass estimation and sizing database for future technology support. This rapid structural analysis process may also facilitate better definition of the vehicles and components for rapid prototyping. However, these structural analysis results are highly conceptual and exploratory in nature and do not reflect current configuration designs being conducted at the program level by NASA and industry.

  10. A new adaptive configuration of PID type fuzzy logic controller.

    PubMed

    Fereidouni, Alireza; Masoum, Mohammad A S; Moghbel, Moayed

    2015-05-01

    In this paper, an adaptive configuration for PID type fuzzy logic controller (FLC) is proposed to improve the performances of both conventional PID (C-PID) controller and conventional PID type FLC (C-PID-FLC). The proposed configuration is called adaptive because its output scaling factors (SFs) are dynamically tuned while the controller is functioning. The initial values of SFs are calculated based on its well-tuned counterpart while the proceeding values are generated using a proposed stochastic hybrid bacterial foraging particle swarm optimization (h-BF-PSO) algorithm. The performance of the proposed configuration is evaluated through extensive simulations for different operating conditions (changes in reference, load disturbance and noise signals). The results reveal that the proposed scheme performs significantly better over the C-PID controller and the C-PID-FLC in terms of several performance indices (integral absolute error (IAE), integral-of-time-multiplied absolute error (ITAE) and integral-of-time-multiplied squared error (ITSE)), overshoot and settling time for plants with and without dead time. PMID:25530256

  11. Experimental Configuration Effects on ICE Tumble Flow Evaluation

    NASA Astrophysics Data System (ADS)

    Santana, Bryan; Puzinauskas, Paulius

    2014-11-01

    The generation of ICE (Internal Combustion Engine) in-cylinder charge motions, such as swirl and tumble, have shown positive effects on reducing fuel consumption and exhaust emission levels at partial engine loads. Tumble flow is commonly measured utilizing a steady-flow rig and two-dimensional PIV (Particle Image Velocimetry) systems, among others. In order to optimize the tumble flow, it is important to retrieve accurate measurements. The tumble flow values could be affected by variations in the geometry and/or design of the steady-flow rig utilized during flow tests. In this research, a four-valve per cylinder head was tested on a steady flow bench, varying several aspects of the configuration to evaluate how they influence bulk momentum as well as PIV measurements. The configuration variations included symmetrical, asymmetrical and runner-fed configurations throughout testing. Volumetric flow rate and tumble strength flow measurements were retrieved at the selected L/D ratios. Additionally, several PIV seeding particles were characterized for size and shape. Corresponding PIV flow measurements using each type of seeding were made to evaluate how the particles influence the results. NSF ECE Grant #1358991 supported Bryan Santana Rivera as an REU student.

  12. Dynamic critical approach to self-organized criticality

    NASA Astrophysics Data System (ADS)

    Laneri, Karina; Rozenfeld, Alejandro F.; Albano, Ezequiel V.

    2005-12-01

    A dynamic scaling ansatz for the approach to the self-organized critical (SOC) regime is proposed and tested by means of extensive simulations applied to the Bak-Sneppen model (BS), which exhibits robust SOC behavior. Considering the short-time scaling behavior of the density of sites [ρ(t)] below the critical value, it is shown that (i) starting the dynamics with configurations such that ρ(t=0)→0 one observes an initial increase of the density with exponent θ=0.12(2) ; (ii) using initial configurations with ρ(t=0)→1 , the density decays with exponent δ=0.47(2) . It is also shown that the temporal autocorrelation decays with exponent Ca=0.35(2) . Using these dynamically determined critical exponents and suitable scaling relationships, all known exponents of the BS model can be obtained, e.g., the dynamical exponent z=2.10(5) , the mass dimension exponent D=2.42(5) , and the exponent of all returns of the activity τALL=0.39(2) , in excellent agreement with values already accepted and obtained within the SOC regime.

  13. Structural dynamics model and response of the deployable reference configuration space station

    NASA Technical Reports Server (NTRS)

    Housner, J. M.

    1985-01-01

    The analytical models and results of a structural dynamics investigation of the reference initial operation and evolutionary configurations of the nine foot bay space station are presented. This investigation was carried out between April and August 1984 as part of a team effort to define a reference configuration for the first U.S. manned space station. The results presented herein serve as a guide, a point of departure and a standard for future NASA and contractor studies leading to the design of the Space Station. The reference initial operation configuration of the nine foot bay station was found to be very flexible, with its lowest mode between 0.096 and 0.138 Hertz depending on station attachments. However, for the transient load cases which were then available, internal member loads had positive margins of safety and preliminary results indicate that laboratory experiments which require quiescent conditions can be satisfied down to the order of 0.0001 g's.

  14. 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).

  15. Load attenuating passively adaptive wind turbine blade

    DOEpatents

    Veers, Paul S.; Lobitz, Donald W.

    2003-01-01

    A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

  16. Load attenuating passively adaptive wind turbine blade

    DOEpatents

    Veers, Paul S.; Lobitz, Donald W.

    2003-01-07

    A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

  17. 14 CFR 27.865 - External loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used... except for the failure of critical structural elements that would result in a hazard to the...

  18. 14 CFR 27.865 - External loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used... except for the failure of critical structural elements that would result in a hazard to the...

  19. 14 CFR 27.865 - External loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used... except for the failure of critical structural elements that would result in a hazard to the...

  20. 14 CFR 27.865 - External loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of any other electrical or mechanical rotorcraft system. (c) For rotorcraft-load combinations to be used... except for the failure of critical structural elements that would result in a hazard to the...

  1. Error-field penetration in reversed magnetic shear configurations

    SciTech Connect

    Wang, H. H.; Wang, Z. X.; Wang, X. Q.; Wang, X. G.

    2013-06-15

    Error-field penetration in reversed magnetic shear (RMS) configurations is numerically investigated by using a two-dimensional resistive magnetohydrodynamic model in slab geometry. To explore different dynamic processes in locked modes, three equilibrium states are adopted. Stable, marginal, and unstable current profiles for double tearing modes are designed by varying the current intensity between two resonant surfaces separated by a certain distance. Further, the dynamic characteristics of locked modes in the three RMS states are identified, and the relevant physics mechanisms are elucidated. The scaling behavior of critical perturbation value with initial plasma velocity is numerically obtained, which obeys previously established relevant analytical theory in the viscoresistive regime.

  2. Rare Relativistic Configuration Interaction Calculations

    NASA Astrophysics Data System (ADS)

    Dinov, Konstantin Dimitrov

    1995-01-01

    Valence shell Relativistic Configuration Interaction (RCI) Calculations for several Rare Earth elements resulted the following electron affinities: (1) Ce^ - 6p attachment to the 4f 5d 6s^2 ^1G_sp{4 }{circ} ground state: (2J,EA) = (9,259 meV), (7,147 meV), [7_ {rm first exc.},55 rm meV], (5,105 meV), (3,43 meV). The electron affinity of the 5d attachment in 4f 5d^2 6s^2 ^5H _{7/2} is 178 meV. (2) Pr ^- 6p attachment to the 4f^3 6s^2 ^4I_sp {9/2}{circ} ground state gives 128 meV for the 4f^3 6s^2 6p J = 5 state (^5K 60%), and 110 meV for the J = 4 state (^5I 42%). No evidence for 5d attachment was found. (3) U^- 7p attachment to the 5f ^3 6d 7s^2 ^5L _sp{6}{circ} ground state gives: 175 meV for the 2J = 13 state (^6M 54%). No other 7p or 6d bound states were found. The hyperfine structure constants for the 5f^3 6d 7s^2 7p, 2J = 13 state are A = -72.4 MHz, B = 2644 MHz. No evidence is found to support f attachment in these species. We investigated two low lying 4f ^2 thresholds in Ce, to which one could attach s or p electron, but neither attachment gives enough energy to bind the negative ion. The missing core-valence effects may reduce the EAs by 0.06 eV, based on the difference between the theoretical predictions and experimental measurements for the electron affinity of Strontium. These results correspond to the observed negative ion yields: high for Ce^ -, moderate for Pr^-, and small for U^-.. The REDUCE method was extensively used for the U^- case. The current version of the RCI program allows up to 7 000 vectors (10M elements) in RAM. The enhancement of the computer programs is by a speed factor of 6, and 7 times bigger matrices. A parallel version of the RCI programs was developed. All of these systems are unbound at the MCDF level (single manifold). By far the biggest contributor to the binding is nsto (n-1)d correlation, while the biggest unbinding comes from ns^2 to np^2 correlation. Other important correlations are: ns^2to (n-1)d^2, (n-1)d nsto np^2 & np

  3. Load Model Data Tool

    SciTech Connect

    David Chassin, Pavel Etingov

    2013-04-30

    The LMDT software automates the process of the load composite model data preparation in the format supported by the major power system software vendors (GE and Siemens). Proper representation of the load composite model in power system dynamic analysis is very important. Software tools for power system simulation like GE PSLF and Siemens PSSE already include algorithms for the load composite modeling. However, these tools require that the input information on composite load to be provided in custom formats. Preparation of this data is time consuming and requires multiple manual operations. The LMDT software enables to automate this process. Software is designed to generate composite load model data. It uses the default load composition data, motor information, and bus information as an input. Software processes the input information and produces load composition model. Generated model can be stored in .dyd format supported by GE PSLF package or .dyr format supported by Siemens PSSE package.

  4. Load Model Data Tool

    Energy Science and Technology Software Center (ESTSC)

    2013-04-30

    The LMDT software automates the process of the load composite model data preparation in the format supported by the major power system software vendors (GE and Siemens). Proper representation of the load composite model in power system dynamic analysis is very important. Software tools for power system simulation like GE PSLF and Siemens PSSE already include algorithms for the load composite modeling. However, these tools require that the input information on composite load to bemore » provided in custom formats. Preparation of this data is time consuming and requires multiple manual operations. The LMDT software enables to automate this process. Software is designed to generate composite load model data. It uses the default load composition data, motor information, and bus information as an input. Software processes the input information and produces load composition model. Generated model can be stored in .dyd format supported by GE PSLF package or .dyr format supported by Siemens PSSE package.« less

  5. Configuration analysis of nickel hydrogen cell

    NASA Technical Reports Server (NTRS)

    Holleck, G.

    1978-01-01

    The significance of various stack configurations and components on the cycle life for nickel hydrogen cells for synchronous orbit used was evaluated. Failure modes of electrolyte management and 02 management were solved by modifications in the reservoir, the wick, and/or the stack configuration.

  6. Configuration-Control Scheme Copes With Singularities

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun; Colbaugh, Richard D.

    1993-01-01

    Improved configuration-control scheme for robotic manipulator having redundant degrees of freedom suppresses large joint velocities near singularities, at expense of small trajectory errors. Provides means to enforce order of priority of tasks assigned to robot. Basic concept of configuration control of redundant robot described in "Increasing The Dexterity Of Redundant Robots" (NPO-17801).

  7. 40 CFR 610.41 - Test configurations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Test configurations. 610.41 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria General Vehicle Test Procedures § 610.41 Test configurations. (a) In order to measure the effectiveness of a retrofit device at least two,...

  8. 14 CFR 35.2 - Propeller configuration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller configuration. 35.2 Section 35.2 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all the components, including references...

  9. Marking up lattice QCD configurations and ensembles

    SciTech Connect

    P.Coddington; B.Joo; C.M.Maynard; D.Pleiter; T.Yoshie

    2007-10-01

    QCDml is an XML-based markup language designed for sharing QCD configurations and ensembles world-wide via the International Lattice Data Grid (ILDG). Based on the latest release, we present key ingredients of the QCDml in order to provide some starting points for colleagues in this community to markup valuable configurations and submit them to the ILDG.

  10. When One Configuration Is Not Enough

    ERIC Educational Resources Information Center

    McMillin, David R.

    2008-01-01

    For most molecules molecular orbital theory predicts a ground-state electronic configuration that is useful for rationalizing relative bond lengths, magnetic properties, and so forth. However, when electron correlation is a dominant consideration, the ground-state configuration may provide a poor representation of the system. In such cases,…

  11. System for Configuring Modular Telemetry Transponders

    NASA Technical Reports Server (NTRS)

    Varnavas, Kosta A. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A system for configuring telemetry transponder cards uses a database of error checking protocol data structures, each containing data to implement at least one CCSDS protocol algorithm. Using a user interface, a user selects at least one telemetry specific error checking protocol from the database. A compiler configures an FPGA with the data from the data structures to implement the error checking protocol.

  12. 40 CFR 610.41 - Test configurations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Test configurations. 610.41 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria General Vehicle Test Procedures § 610.41 Test configurations. (a) In order to measure the effectiveness of a retrofit device at least two,...

  13. 40 CFR 610.41 - Test configurations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Test configurations. 610.41 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria General Vehicle Test Procedures § 610.41 Test configurations. (a) In order to measure the effectiveness of a retrofit device at least two,...

  14. 40 CFR 610.41 - Test configurations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Test configurations. 610.41 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria General Vehicle Test Procedures § 610.41 Test configurations. (a) In order to measure the effectiveness of a retrofit device at least two,...

  15. 14 CFR 35.2 - Propeller configuration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller configuration. 35.2 Section 35.2 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all...

  16. Structural dynamics and attitude control study of early manned capability space station configurations

    NASA Technical Reports Server (NTRS)

    Ayers, J. Kirk; Cirillo, William M.; Giesy, Daniel P.; Hitchcock, Jay C.; Kaszubowski, Martin J.; Raney, J. Philip

    1987-01-01

    A study was performed to determine the vibration and attitude control characteristics of critical space station configurations featuring early manned capability during buildup from initial user support through the operations capability reference station. Five configurations were selected and were examined thus determining the changes that are likely to occur in the characteristics of the system as the station progresses from a single boom structure to a mature, dual keel, operations capability reference station. Both 9 foot and 5 meter truss bay sizes were investigated. All configurations analyzed were stable; however, the 5 meter truss bay size structure exhibited superior stability characteristics.

  17. Fracture mechanics analysis for various fiber/matrix interface loadings

    NASA Technical Reports Server (NTRS)

    Naik, R. A.; Crews, J. H., Jr.

    1991-01-01

    Fiber/matrix (F/M) cracking was analyzed to provide better understanding and guidance in developing F/M interface fracture toughness tests. Two configurations, corresponding to F/M cracking at a broken fiber and at the free edge, were investigated. The effects of mechanical loading, thermal cooldown, and friction were investigated. Each configuration was analyzed for two loadings: longitudinal and normal to the fiber. A nonlinear finite element analysis was performed to model friction and slip at the F/M interface. A new procedure for fitting a square-root singularity to calculated stresses was developed to determine stress intensity factors (K sub I and K sub II) for a bimaterial interface crack. For the case of F/M cracking at a broken fiber with longitudinal loading, crack tip conditions were strongly influenced by interface friction. As a result, an F/M interface toughness test based on this case was not recommended because nonlinear data analysis methods would be required. For the free edge crack configuration, both mechanical and thermal loading caused crack opening, thereby avoiding frictional effects. A F/M interface toughness test based on this configuration would provide data for K(sub I)/K(sub II) ratios of about 0.7 and 1.6 for fiber and radial normal loading, respectively. However, thermal effects must be accounted for in the data analysis.

  18. Fracture mechanics analysis for various fiber/matrix interface loadings

    NASA Technical Reports Server (NTRS)

    Naik, Rajiv A.; Crews, John H., Jr.

    1992-01-01

    Fiber/matrix (F/M) cracking was analyzed to provide better understanding and guidance in developing F/M interface fracture toughness tests. Two configurations, corresponding to F/M cracking at a broken fiber and at the free edge, were investigated. The effects of mechanical loading, thermal cooldown, and friction were investigated. Each configuration was analyzed for two loadings: longitudinal and normal to the fiber. A nonlinear finite element analysis was performed to model friction and slip at the F/M interface. A new procedure for fitting a square-root singularity to calculated stresses was developed to determine stress intensity factors (K sub I and K sub II) for a bimaterial interface crack. For the case of F/M cracking at a broken fiber with longitudinal loading, crack tip conditions were strongly influenced by interface friction. As a result, an F/M interface toughness test based on this case was not recommended because nonlinear data analysis methods would be required. For the free edge crack configuration, both mechanical and thermal loading caused crack opening, theory avoiding fractional effects. A F/M interface toughness test based on this configuration would provide data for K(sub I/K(sub II) ratios of about 0.7 and 1.6 for fiber and radial normal loading, respectively. However, thermal effects must be accounted for in the data analysis.

  19. Fracture mechanics analysis for various fiber/matrix interface loadings

    NASA Technical Reports Server (NTRS)

    Naik, R. A.; Crews, J. H., Jr.

    1991-01-01

    Fiber/matrix (F/M) cracking was analyzed to provide better understanding and guidance in developing F/M interface fracture toughness tests. Two configurations, corresponding to F/M cracking at a broken fiber and at the free edge, were investigated. The effects of mechanical loading, thermal cooldown, and friction were investigated. Each configuration was analyzed for two loadings: longitudinal and normal to the fiber. A nonlinear finite element analysis was performed to model friction and slip at the F/M interface. A new procedure for fitting a square-root singularity to calculated stresses was developed to determine stress intensity factors (K sub I and K sub II) for a bimaterial interface crack. For the case of F/M cracking at a broken fiber with longitudinal loading, crack tip conditions were strongly influenced by interface friction. As a result, an F/M interface toughness test based on this case was not recommended because nonlinear data analysis methods would be required. For the free edge crack configuration, both mechanical and thermal loading caused crack opening, thereby avoiding frictional effects. An F/M interface toughness test based on this configuration would provide data for K(sub I)/K(sub II) ratios of about 0.7 and 1.6 for fiber and radial normal loading, respectively. However, thermal effects must be accounted for in the data analysis.

  20. Critical Branches and Lucky Loads in Control-Independence Architectures

    ERIC Educational Resources Information Center

    Malik, Kshitiz

    2009-01-01

    Branch mispredicts have a first-order impact on the performance of integer applications. Control Independence (CI) architectures aim to overlap the penalties of mispredicted branches with useful execution by spawning control-independent work as separate threads. Although control independent, such threads may consume register and memory values…

  1. Centaur Standard Shroud (CSS) static ultimate load structural tests

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A series of tests were conducted on the jettisonable metallic shroud used on the Titan/Centaur launch vehicle to verify its structural capabilities and to evaluate its structural interaction with the Centaur stage. A flight configured shroud and the interfacing Titan/Centaur structural assemblies were subjected to tests consisting of combinations of applied axial and shear loads to design ultimate values, including a set of tests on thermal conditions and two dynamic response tests to verify the analytical stiffness model. The strength capabilities were demonstrated at ultimate (125 percent of design limit) loads. It was also verified that the spring rate of the flight configured shroud-to-Centaur forward structural deflections of the specimen became nonlinear, as expected, above limit load values. This test series qualification program verified that the Titan/Centaur shroud and the Centaur and Titan interface components are qualified structurally at design ultimate loads.

  2. Configuration Management Plan for K Basins

    SciTech Connect

    Weir, W.R.; Laney, T.

    1995-01-27

    This plan describes a configuration management program for K Basins that establishes the systems, processes, and responsibilities necessary for implementation. The K Basins configuration management plan provides the methodology to establish, upgrade, reconstitute, and maintain the technical consistency among the requirements, physical configuration, and documentation. The technical consistency afforded by this plan ensures accurate technical information necessary to achieve the mission objectives that provide for the safe, economic, and environmentally sound management of K Basins and the stored material. The configuration management program architecture presented in this plan is based on the functional model established in the DOE Standard, DOE-STD-1073-93, {open_quotes}Guide for Operational Configuration Management Program{close_quotes}.

  3. Evolution of the Configuration Database Design

    SciTech Connect

    Salnikov, A

    2006-04-19

    The BABAR experiment at SLAC successfully collects physics data since 1999. One of the major parts of its on-line system is the configuration database which provides other parts of the system with the configuration data necessary for data taking. Originally the configuration database was implemented in the Objectivity/DB ODBMS. Recently BABAR performed a successful migration of its event store from Objectivity/DB to ROOT and this prompted a complete phase-out of the Objectivity/DB in all other BABAR databases. It required the complete redesign of the configuration database to hide any implementation details and to support multiple storage technologies. In this paper we describe the process of the migration of the configuration database, its new design, implementation strategy and details.

  4. CFD Simulations of Tiltrotor Configurations in Hover

    NASA Technical Reports Server (NTRS)

    Potsdam, Mark a.; Strawn, Roger C.

    2002-01-01

    Navier-Stokes computational fluid dynamics calculations are presented for isolated, half-span, and full-span V-22 tiltrotor hover configurations. These computational results extend the validity of CFD hover methodology beyond conventional rotorcraft applications to tiltrotor configurations. Computed steady-state, isolated rotor performance agrees well with experimental measurements, showing little sensitivity to grid resolution. However, blade-vortex interaction flowfield details are sensitive to numerical dissipation and are more difficult to model accurately. Time-dependent, dynamic, half- and full-span installed configurations show sensitivities in performance to the tiltrotor fountain flow. As such, the full-span configuration exhibits higher rotor performance and lower airframe download than the half-span configuration. Half-span rotor installation trends match available half-span data, and airframe downloads are reasonably well predicted. Overall, the CFD solutions provide a wealth of flowfield details that can be used to analyze and improve tiltrotor aerodynamic performance.

  5. Failure of laminated composites at thickness discontinuities under complex loading and elevated temperatures

    NASA Astrophysics Data System (ADS)

    Lee, Sangwook

    1998-12-01

    Failure initiation of laminated composites with discontinuous thickness is examined in terms of typical structural load description (tension, shear force and bending moment) rather than in terms of micromechanics considerations. Because transverse shear produced relatively small effects in failure initiation, results are presented as tension-bending interactions. Two loading frames were designed to apply moments and tension simultaneously. Four types of specimens of different stacking sequence were examined to determine failure initiation, and analyzed subsequently via a finite element analysis (ABAQUS). Depending on the stacking sequence across the interface of the step, two different failure modes are identified: For uni-directional fiber orientation across the interface in the tension direction, failure occurs through cracking and delamination which is governed by a fracture mechanics criterion. While the initiation strength for this failure mode is higher than for the cross-ply configurations, the residual strength after initiation is only marginally higher, providing virtually no margin of safety (10%). For cases involving cross-plies on either side of the interface, failure initiation occurs by matrix cracking, with a critical strain across the fibers providing a universal failure criterion. In these cases the residual load bearing capability was 30 to 45% higher than the failure initiation loads. The interaction between moment and tension at failure initiation is linear, an observation that does not hold for the delamination failure driven by crack propagation. It is found that all failures can be described in terms of a common fracture principle; the stress or strain criteria are interchangeable with the fracture energy computations, provided one allows for a range of values of associated fracture energies. Assuming that time dependent aspects of the failure process are not dominant, elevated temperatures did not change the general results of how bending

  6. Accurate rotor loads prediction using the FLAP (Force and Loads Analysis Program) dynamics code

    SciTech Connect

    Wright, A.D.; Thresher, R.W.

    1987-10-01

    Accurately predicting wind turbine blade loads and response is very important in predicting the fatigue life of wind turbines. There is a clear need in the wind turbine community for validated and user-friendly structural dynamics codes for predicting blade loads and response. At the Solar Energy Research Institute (SERI), a Force and Loads Analysis Program (FLAP) has been refined and validated and is ready for general use. Currently, FLAP is operational on an IBM-PC compatible computer and can be used to analyze both rigid- and teetering-hub configurations. The results of this paper show that FLAP can be used to accurately predict the deterministic loads for rigid-hub rotors. This paper compares analytical predictions to field test measurements for a three-bladed, upwind turbine with a rigid-hub configuration. The deterministic loads predicted by FLAP are compared with 10-min azimuth averages of blade root flapwise bending moments for different wind speeds. 6 refs., 12 figs., 3 tabs.

  7. Response of long shallow cylindrical panels to radial line loads

    NASA Technical Reports Server (NTRS)

    Johnson, E. R.; Hyer, M. W.; Carper, D. M.

    1984-01-01

    The large displacement static response of shallow orthotropic panels subjected to lateral loading is examined both theoretically and experimentally. The panels are circular cylindrical open shells which are also thin and long. The straight edges are simply supported at a fixed distance apart, and the curved edges are free. The lateral load is a spatially uniform line load acting along the generator direction of the cylinder, and is directed radially inward toward the center of curvature. The load induces a circumferential thrust, and the panel can, and does, snap-through to an inverted configuration at the buckling load. The effect of load position on the response is also examined. The test panels discussed in the paper are /(90/0)3/S graphite-epoxy laminates. Nominal dimensions are a radius of 60 in., a thickness of 0.060 in., and an arc length of 12 in. Very good agreement between theory and experiment is achieved.

  8. Learjet Model 55 Wing Analysis with Landing Loads

    NASA Technical Reports Server (NTRS)

    Boroughs, R. R.

    1985-01-01

    The NASTRAN analysis was used to determine the impact of new landing loads on the Learjet Model 55 wing. These new landing loads were the result of a performance improvement effort to increase the landing weight of the aircraft to 18,000 lbs. from 17,000 lbs. and extend the life of the tires and brakes by incorporating larger tires and heavy duty brakes. Landing loads for the original 17,000 lb. airplane landing configuration were applied to the full airplane NASTRAN model. The analytical results were correlated with the strain gage data from the original landing load static tests. The landing loads for the 18,000 lb. airplane were applied to the full airplane NASTRAN model, and a comparison was made with the original Model 55 data. The results of this comparison enable Learjet to determine the difference in stress distribution in the wing due to these two different sets of landing loads.

  9. Progression of damage and fracture in composites under dynamic loading

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Murthy, Pappu L. N.; Chamis, Christos C.

    1990-01-01

    A new computational simulation method is presented to evaluate the dynamic aspects of composite structural response and durability that have not been simulated previously. Composite structural behavior under any loading condition, geometry, composite system, laminate configuration, and boundary conditions can now be simulated. Structural degradation, delamination, fracture, and damage propagation are included in the simulation. An angle-plied composite plate structure under normal impact loading is used as an example to demonstrate the versatility of the simulation method.

  10. Wind-tunnel investigation of a full-scale canard-configured general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Yip, L. P.; Coy, P. F.

    1982-01-01

    As part of a broad research program to provide a data base on advanced airplane configurations, a wind-tunnel investigation was conducted in the Langley 30-by 60-Foot Wind Tunnel to determine the aerodynamic characteristics of an advanced canard-configured general aviation airplane. The investigation included measurements of forces and moments of the complete configuration, isolated canard loads, and pressure distributions on the wing, winglet, and canard. Flow visualization was obtained by using surface tufts to determine regions of flow separation and by using a chemical sublimation technique to determine boundary-layer transition locations. Additionally, other tests were conducted to determine simulated rain effects on boundary layer transition. Investigation of configuration effects included variations of canard locations, canard airfoil section, winglet size, and use of a leading-edge droop on the out-board section of the wing.

  11. Comparative performance of several SST configurations powered by noise limited turbojet engines

    NASA Technical Reports Server (NTRS)

    Whitlow, J. B., Jr.

    1972-01-01

    A simplified study was made in which the mission performances of three Mach 2.7 airplane configurations were compared. Both wing loading and size of the unaugmented turbojet engines were varied at different levels of suppressor technology. The lowest gross weight and the best return on investment were obtained with an advanced arrow wing configuration when a mission range of 4200 nautical miles was specified. This comparison was made for the takeoff noise levels specified in F.A.R. 36 using retractable jet noise suppressors assumed to be capable of 15 PNdb of suppression with only a 7.5-percent thrust loss. With less advanced suppressor technology, a modified delta configuration is a close competitor of the arrow wing. Despite its good takeoff characteristics, a swing-wing configuration was too structurally heavy to be competitive at F.A.R. 36 noise levels. Engine performance and weight commensurate with engine definition in 1975 were postulated.

  12. Critical Pedagogy for Critical Mathematics Education

    ERIC Educational Resources Information Center

    Tutak, Fatma Aslan; Bondy, Elizabeth; Adams, Thomasenia L.

    2011-01-01

    This article provides a brief introduction to critical pedagogy and further discussion on critical mathematics education. Critical mathematics education enables students to read the world with mathematics. Three emerging domains of mathematics education related to critical mathematics education are discussed in this manuscript: ethnomathematics,…

  13. Dynamic load cases on Ariane 5

    NASA Astrophysics Data System (ADS)

    Chemoul, B.; Louaas, E.

    1991-10-01

    Ariane 5 will be able to launch payloads weighing up to 20 tons. The environmental requirements for these various payloads must be given early in the launcher's development's program. The first launcher's intrumented tests have not yet begun and for this reason some load cases still remain unknown (e.g. engines thrust decay). To find those load cases, assumptions must be made using the experience of previous programs. If this experience does not exist and if the expected load cases are supposed to be critical, particular studies must be carried out (e.g. blast wave). The low frequency load cases considered on Ariane 5 to establish the environmental requirements depend on the flight phases: lift off (blastwave, symmetrical and unsymmetrical ignition); aerodynamic flight (transonic or max dynamic pressure) gust; and end of stage's thrust (strap on boosters, Vulcain, upperstage). Several causes are presented and analyzed. Applications with Astral are shown considering the dynamical coupling between Ariane 5 and standard payloads.

  14. Mechanical Predictors of Discomfort during Load Carriage.

    PubMed

    Wettenschwiler, Patrick D; Lorenzetti, Silvio; Stämpfli, Rolf; Rossi, René M; Ferguson, Stephen J; Annaheim, Simon

    2015-01-01

    Discomfort during load carriage is a major issue for activities using backpacks (e.g. infantry maneuvers, children carrying school supplies, or outdoor sports). It is currently unclear which mechanical parameters are responsible for subjectively perceived discomfort. The aim of this study was to identify objectively measured mechanical predictors of discomfort during load carriage. We compared twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt. The pressure distribution under the hip belt and the shoulder strap, as well as the tensile force in the strap and the relative motion of the backpack were measured. Multiple linear regression analyses were conducted to investigate possible predictors of discomfort. The results demonstrate that static peak pressure, or alternatively, static strap force is a significant (p<0.001) predictor of discomfort during load carriage in the shoulder and hip region, accounting for 85% or more of the variation in discomfort. As an additional finding, we discovered that the regression coefficients of these predictors are significantly smaller for the hip than for the shoulder region. As static peak pressure is measured directly on the body, it is less dependent on the type of load carriage system than static strap force. Therefore, static peak pressure is well suited as a generally applicable, objective mechanical parameter for the optimization of load carriage system design. Alternatively, when limited to load carriage systems of the type backpack with hip belt, static strap force is the most valuable predictor of discomfort. The regionally differing regression coefficients of both predictors imply that the hip region is significantly more tolerant than the shoulder region. In order to minimize discomfort, users should be encouraged to shift load from the shoulders to the hip region wherever possible, at the same time likely decreasing the risk of low back pain or injury

  15. Mechanical Predictors of Discomfort during Load Carriage

    PubMed Central

    Wettenschwiler, Patrick D.; Lorenzetti, Silvio; Stämpfli, Rolf; Rossi, René M.; Ferguson, Stephen J.; Annaheim, Simon

    2015-01-01

    Discomfort during load carriage is a major issue for activities using backpacks (e.g. infantry maneuvers, children carrying school supplies, or outdoor sports). It is currently unclear which mechanical parameters are responsible for subjectively perceived discomfort. The aim of this study was to identify objectively measured mechanical predictors of discomfort during load carriage. We compared twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt. The pressure distribution under the hip belt and the shoulder strap, as well as the tensile force in the strap and the relative motion of the backpack were measured. Multiple linear regression analyses were conducted to investigate possible predictors of discomfort. The results demonstrate that static peak pressure, or alternatively, static strap force is a significant (p<0.001) predictor of discomfort during load carriage in the shoulder and hip region, accounting for 85% or more of the variation in discomfort. As an additional finding, we discovered that the regression coefficients of these predictors are significantly smaller for the hip than for the shoulder region. As static peak pressure is measured directly on the body, it is less dependent on the type of load carriage system than static strap force. Therefore, static peak pressure is well suited as a generally applicable, objective mechanical parameter for the optimization of load carriage system design. Alternatively, when limited to load carriage systems of the type backpack with hip belt, static strap force is the most valuable predictor of discomfort. The regionally differing regression coefficients of both predictors imply that the hip region is significantly more tolerant than the shoulder region. In order to minimize discomfort, users should be encouraged to shift load from the shoulders to the hip region wherever possible, at the same time likely decreasing the risk of low back pain or injury

  16. Improving motorcycle conspicuity through innovative headlight configurations.

    PubMed

    Ranchet, Maud; Cavallo, Viola; Dang, Nguyen-Thong; Vienne, Fabrice

    2016-09-01

    Most motorcycle crashes involve another vehicle that violated the motorcycle's right-of-way at an intersection. Two kinds of perceptual failures of other road users are often the cause of such accidents: motorcycle-detection failures and motion-perception errors. The aim of this study is to investigate the effect of different headlight configurations on motorcycle detectability when the motorcycle is in visual competition with cars. Three innovative headlight configurations were tested: (1) standard yellow (central yellow headlight), (2) vertical white (one white light on the motorcyclist's helmet and two white lights on the fork in addition to the central white headlight), and (3) vertical yellow (same configuration as (2) with yellow lights instead of white). These three headlight configurations were evaluated in comparison to the standard configuration (central white headlight) in three environments containing visual distractors formed by car lights: (1) daytime running lights (DRLs), (2) low beams, or (3) DRLs and low beams. Video clips of computer-generated traffic situations were displayed briefly (250ms) to 57 drivers. The results revealed a beneficial effect of standard yellow configuration and the vertical yellow configuration on motorcycle detectability. However, this effect was modulated by the car-DRL environment. Findings and practical recommendations are discussed with regard to possible applications for motorcycles. PMID:27280780

  17. Zigzag configurations and air classifier performance

    SciTech Connect

    Peirce, J.; Wittenberg, N.

    1984-03-01

    The fundamental aspects of zigzag air classifier configurations are studied in terms of the design and operation of a waste-to-energy production facility. The development of a method of performance evaluation defined by operating range is examined. Historically, air classification has been used in industry and agriculture in mineral extraction, limestone sizing, and seed and grain cleaning. However, the adaption of air classifiers to resource recovery and waste-to-energy production facilities presents new problems due to the complex and variable nature of the wastes. A series of configurations providing a continuous range of zigzag classifier shape components are tested. Each configuration is evaluated to determine its efficiency of separation, and sensitivity to operating air speeds. Results indicate that the configuration of a zigzag classifier does not influence its peak efficiency of separation. However, findings point to distinct limits on operating parameters which lead to peak efficiencies for the different configurations. These operating range values represent the sensitivity of the air classifier to changes in the air flow. A major finding concerns the effect of configuration on the particle size distribution observed in the material exiting the classifier: smaller particles appear to be influenced by configuration changes and larger particles do not. A new method for classifer performance evaluation is developed and applied.

  18. Zigzag configurations and air classifier performance

    SciTech Connect

    Peirce, J.J.; Wittenberg, N.

    1984-03-01

    The fundamental aspects of zigzag air classifier configurations are studied in terms of the design and operation of a waste-to-energy production facility. The development of a method of performance evaluation defined by operating range is examined. Historically, air classification has been used in industry and agriculture in mineral extraction, limestone sizing, and seed and grain cleaning. However, the adaption of air classifiers to resource recovery and waste-to-energy production facilities presents new problems due to the complex and variable nature of the wastes. A series of configurations providing a continuous range of zigzag classifier shape components are tested. Each configuration is evaluated to determine its efficiency of separation, and sensitivity to operating air speeds. Results indicate that the configuration of a zigzag classifier does not influence its peak efficiency of separation. However, findings point to distinct limits on operating parameters which lead to peak efficiencies for the different configurations. These operating range values represent the sensitivity of the air classifier to changes in the air flow. A major finding concerns the effect of configuration on the particle size distribution observed in the material exiting the classifier: smaller particles appear to be influenced by configuration changes and larger particles do not. A new method for classifier performance evaluation is developed and applied.

  19. Phalange Tactile Load Cell

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas Martin (Inventor); Platt, Robert (Inventor); Griffith, Bryan Kristian (Inventor)

    2010-01-01

    A tactile load cell that has particular application for measuring the load on a phalange in a dexterous robot system. The load cell includes a flexible strain element having first and second end portions that can be used to mount the load cell to the phalange and a center portion that can be used to mount a suitable contact surface to the load cell. The strain element also includes a first S-shaped member including at least three sections connected to the first end portion and the center portion and a second S-shaped member including at least three sections coupled to the second end portion and the center portion. The load cell also includes eight strain gauge pairs where each strain gauge pair is mounted to opposing surfaces of one of the sections of the S-shaped members where the strain gauge pairs provide strain measurements in six-degrees of freedom.

  20. Mississippi River nitrate loads from high frequency sensor measurements and regression-based load estimation

    USGS Publications Warehouse

    Pellerin, Brian A.; Bergamaschi, Brian A.; Gilliom, Robert J.; Crawford, Charles G.; Saraceno, John F.; Frederick, C. Paul; Downing, Bryan D.; Murphy, Jennifer C.

    2014-01-01

    Accurately quantifying nitrate (NO3–) loading from the Mississippi River is important for predicting summer hypoxia in the Gulf of Mexico and targeting nutrient reduction within the basin. Loads have historically been modeled with regression-based techniques, but recent advances with high frequency NO3– sensors allowed us to evaluate model performance relative to measured loads in the lower Mississippi River. Patterns in NO3– concentrations and loads were observed at daily to annual time steps, with considerable variability in concentration-discharge relationships over the two year study. Differences were particularly accentuated during the 2012 drought and 2013 flood, which resulted in anomalously high NO3– concentrations consistent with a large flush of stored NO3– from soil. The comparison between measured loads and modeled loads (LOADEST, Composite Method, WRTDS) showed underestimates of only 3.5% across the entire study period, but much larger differences at shorter time steps. Absolute differences in loads were typically greatest in the spring and early summer critical to Gulf hypoxia formation, with the largest differences (underestimates) for all models during the flood period of 2013. In additional to improving the accuracy and precision of monthly loads, high frequency NO3– measurements offer additional benefits not available with regression-based or other load estimation techniques.

  1. Mississippi River nitrate loads from high frequency sensor measurements and regression-based load estimation.

    PubMed

    Pellerin, Brian A; Bergamaschi, Brian A; Gilliom, Robert J; Crawford, Charles G; Saraceno, JohnFranco; Frederick, C Paul; Downing, Bryan D; Murphy, Jennifer C

    2014-11-01

    Accurately quantifying nitrate (NO3-) loading from the Mississippi River is important for predicting summer hypoxia in the Gulf of Mexico and targeting nutrient reduction within the basin. Loads have historically been modeled with regression-based techniques, but recent advances with high frequency NO3- sensors allowed us to evaluate model performance relative to measured loads in the lower Mississippi River. Patterns in NO3- concentrations and loads were observed at daily to annual time steps, with considerable variability in concentration-discharge relationships over the two year study. Differences were particularly accentuated during the 2012 drought and 2013 flood, which resulted in anomalously high NO3- concentrations consistent with a large flush of stored NO3- from soil. The comparison between measured loads and modeled loads (LOADEST, Composite Method, WRTDS) showed underestimates of only 3.5% across the entire study period, but much larger differences at shorter time steps. Absolute differences in loads were typically greatest in the spring and early summer critical to Gulf hypoxia formation, with the largest differences (underestimates) for all models during the flood period of 2013. In additional to improving the accuracy and precision of monthly loads, high frequency NO3- measurements offer additional benefits not available with regression-based or other load estimation techniques. PMID:25310505

  2. Truck loading positions for maximum live load girder moment in skewed integral bridges

    NASA Astrophysics Data System (ADS)

    Yalcin, O. Fatih

    2015-12-01

    In this study, the effect of the longitudinal and transverse truck positions on the distribution of live load moment among the girders of skewed integral abutment bridges (SIBs) is investigated. For this purpose, three dimensional finite element models (FEMs) of several single-span SIBs are built and analyzed. In the analyses, bridges with various skew angles under all possible single and double truck loading positions both in longitudinal and transverse directions are considered. An automated analysis procedure managed by a visual basic program is developed to obtain the structural models and apply the wheel loads of trucks. The finite element analyses (FEA) results are then used to find the most critical loading cases of single truck and adjacent two trucks for the live load moment in the girders of SIBs. The results revealed that, the trucks should be placed nearby the midline of the bridge deck in a diagonal manner.

  3. ARES I-X USS Fracture Analysis Loads Spectra Development

    NASA Technical Reports Server (NTRS)

    Larsen, Curtis; Mackey, Alden

    2008-01-01

    This report describes the development of a set of bounding load spectra for the ARES I-X launch vehicle. These load spectra are used in the determination of the critical initial flaw size (CIFS) of the welds in the ARES I-X upper stage simulator (USS).

  4. Strategy Guideline. Accurate Heating and Cooling Load Calculations

    SciTech Connect

    Burdick, Arlan

    2011-06-01

    This guide presents the key criteria required to create accurate heating and cooling load calculations and offers examples of the implications when inaccurate adjustments are applied to the HVAC design process. The guide shows, through realistic examples, how various defaults and arbitrary safety factors can lead to significant increases in the load estimate. Emphasis is placed on the risks incurred from inaccurate adjustments or ignoring critical inputs of the load calculation.

  5. Strategy Guideline: Accurate Heating and Cooling Load Calculations

    SciTech Connect

    Burdick, A.

    2011-06-01

    This guide presents the key criteria required to create accurate heating and cooling load calculations and offers examples of the implications when inaccurate adjustments are applied to the HVAC design process. The guide shows, through realistic examples, how various defaults and arbitrary safety factors can lead to significant increases in the load estimate. Emphasis is placed on the risks incurred from inaccurate adjustments or ignoring critical inputs of the load calculation.

  6. Flight loads and control

    NASA Technical Reports Server (NTRS)

    Mowery, D. K.; Winder, S. W.

    1972-01-01

    The prediction of flight loads and their potential reduction, using various control logics for the space shuttle vehicles, is very complex. Some factors, not found on previous launch vehicles, that increase the complexity are large lifting surfaces, unsymmetrical structure, unsymmetrical aerodynamics, trajectory control system coupling, and large aeroelastic effects. Discussed are these load producing factors and load reducing techniques. Identification of potential technology areas is included.

  7. Configuration effects on satellite charging response

    NASA Technical Reports Server (NTRS)

    Purvis, C. K.

    1980-01-01

    The response of various spacecraft configurations to a charging environment in sunlight was studied using the NASA Charging Analyzer Program code. The configuration features geometry, type of stabilization, and overall size. Results indicate that sunlight charging response is dominated by differential charging effects. Shaded insulation charges negatively result in the formation of potential barriers which suppress photoelectron emission from sunlit surfaces. Sunlight charging occurs relatively slowly: with 30 minutes of charging simulations, in none of the configurations modeled did the most negative surface cell reach half its equilibrium potential in eclipse.

  8. Atom localization with double-cascade configuration

    NASA Astrophysics Data System (ADS)

    Gordeev, Maksim Yu; Efremova, Ekaterina A.; Rozhdestvensky, Yuri V.

    2016-03-01

    We investigate the one-dimensional (1D) and two-dimensional (2D) atom localization of a four-level system in a double-cascade configuration. We demonstrate the possibility of 1D localization in the field of a standing wave, 2D localization in the field of two standing waves and 2D localization only in the field of running waves by using different configurations of driven waves on transitions. In addition, for each configuration we reached a high-precision atom localization in one of the states at scales much smaller than the wavelength of the incident optical radiation.

  9. PDSS configuration control plan and procedures

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The payload development support system (PDSS) configuration control plan and procedures are presented. These plans and procedures establish the process for maintaining configuration control of the PDSS system, especially the Spacelab experiment interface device's (SEID) RAU, HRM, and PDI interface simulations and the PDSS ECOS DEP Services simulation. The plans and procedures as specified are designed to provide a simplified but complete configuration control process. The intent is to require a minimum amount of paperwork but provide total traceability of PDSS during experiment test activities.

  10. Space Transportation Booster Engine (STBE) configuration study

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The overall objective of this Space Transportation Booster Engine (STBE) study is to identify candidate engine configurations which enhance vehicle performance and provide operational flexibility at low cost. The specific objectives are as follows: (1) to identify and evaluate candidate LOX/HC engine configurations for the Advanced Space Transportation System for an early 1995 IOC and a late 2000 IOC; (2) to select one optimum engine for each time period; 3) to prepare a conceptual design for each configuration; (4) to develop a technology plan for the 2000 IOC engine; and, (5) to prepare preliminary programmatic planning and analysis for the 1995 IOC engine.

  11. Metastable configurations of small-world networks.

    PubMed

    Heylen, R; Skantzos, N S; Blanco, J Busquets; Bollé, D

    2006-01-01

    We calculate the number of metastable configurations of Ising small-world networks that are constructed upon superimposing sparse Poisson random graphs onto a one-dimensional chain. Our solution is based on replicated transfer-matrix techniques. We examine the denegeracy of the ground state and find a jump in the entropy of metastable configurations exactly at the crossover between the small-world and the Poisson random graph structures. We also examine the difference in entropy between metastable and all possible configurations, for both ferromagnetic and bond-disordered long-range couplings. PMID:16486247

  12. Metastable configurations of small-world networks

    NASA Astrophysics Data System (ADS)

    Heylen, R.; Skantzos, N. S.; Blanco, J. Busquets; Bollé, D.

    2006-01-01

    We calculate the number of metastable configurations of Ising small-world networks that are constructed upon superimposing sparse Poisson random graphs onto a one-dimensional chain. Our solution is based on replicated transfer-matrix techniques. We examine the denegeracy of the ground state and find a jump in the entropy of metastable configurations exactly at the crossover between the small-world and the Poisson random graph structures. We also examine the difference in entropy between metastable and all possible configurations, for both ferromagnetic and bond-disordered long-range couplings.

  13. Rigged Configurations and the Bethe Ansatz

    NASA Astrophysics Data System (ADS)

    Schilling, Anne

    2003-07-01

    This note is a review of rigged configurations and the Bethe Ansatz. In the first part, we focus on the algebraic Bethe Ansatz for the spin 1/2 XXX model and explain how rigged configurations label the solutions of the Bethe equations. This yields the bijection between rigged configurations and crystal paths/Young tableaux of Kerov, Kirillov and Reshetikhin. In the second part, we discuss a generalization of this bijection for the symmetry algebra Dn(1) , based on work in collaboration with Okado and Shimozono.

  14. A Criticality Safety Study on Storing Unirradiated Cintichem-Type Targets at Sandia National Laboratories

    SciTech Connect

    Romero, D.J.; Parma, E.J.; Busch, R.D.

    1999-04-21

    This criticality safety analysis is performed to determine the effective multiplication factor (k{sub eff}) for a storage cabinet filled with unirradiated Cintichem-type targets. These targets will be used to produce {sup 99}Mo at Sandia National Laboratories and will be stored on-site prior to irradiation in the Annular Core Research Reactor. The analysis consisted of using the Monte Carlo code MCNP (Version 4A) to model and predict the k{sub eff} for the proposed dry storage configuration under credible loss of geometry and moderator control. Effects of target pitch, non-uniform loading, and target internal/external flooding are evaluated. Further studies were done with deterministic methods to verify the results obtained from MCNP and to obtain a clearer understanding of the parameters affecting system criticality. The diffusion accelerated neutral particle transport code ONEDANT was used to model the target in a one-dimensional, infinite half-slab geometry and determine the critical slab thickness. Hand calculations were also completed to determine the critical slab thickness with modified one-group, and one-group, two region approximations. Results obtained from ONEDANT and the hand calculations were compared to applicable cases in a commonly used criticality safety analysis handbook. Overall, the critical slab thicknesses obtained in the deterministic analysis were much larger than the dimensions of the cabinet and further support the predictions by MCNP that a critical system cannot be attained for the base case or in conditions where loss of geometry and moderation control occur.

  15. Load regulating expansion fixture

    DOEpatents

    Wagner, Lawrence M.; Strum, Michael J.

    1998-01-01

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components.

  16. Load regulating expansion fixture

    DOEpatents

    Wagner, L.M.; Strum, M.J.

    1998-12-15

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils is disclosed. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components. 1 fig.

  17. Load sensing system

    DOEpatents

    Sohns, C.W.; Nodine, R.N.; Wallace, S.A.

    1999-05-04

    A load sensing system inexpensively monitors the weight and temperature of stored nuclear material for long periods of time in widely variable environments. The system can include an electrostatic load cell that encodes weight and temperature into a digital signal which is sent to a remote monitor via a coaxial cable. The same cable is used to supply the load cell with power. When multiple load cells are used, vast inventories of stored nuclear material can be continuously monitored and inventoried of minimal cost. 4 figs.

  18. Impact of sampling strategy on stream load estimates in till landscape of the Midwest

    USGS Publications Warehouse

    Vidon, P.; Hubbard, L.E.; Soyeux, E.

    2009-01-01

    Accurately estimating various solute loads in streams during storms is critical to accurately determine maximum daily loads for regulatory purposes. This study investigates the impact of sampling strategy on solute load estimates in streams in the US Midwest. Three different solute types (nitrate, magnesium, and dissolved organic carbon (DOC)) and three sampling strategies are assessed. Regardless of the method, the average error on nitrate loads is higher than for magnesium or DOC loads, and all three methods generally underestimate DOC loads and overestimate magnesium loads. Increasing sampling frequency only slightly improves the accuracy of solute load estimates but generally improves the precision of load calculations. This type of investigation is critical for water management and environmental assessment so error on solute load calculations can be taken into account by landscape managers, and sampling strategies optimized as a function of monitoring objectives. ?? 2008 Springer Science+Business Media B.V.

  19. Peering inside the granular bed: illuminating feedbacks between bed-load transport and bed-structure evolution

    NASA Astrophysics Data System (ADS)

    Houssais, M.; Jerolmack, D. J.; Martin, R. L.

    2013-12-01

    The threshold of motion is perhaps the most important quantity to determine for understanding rates of bed load transport, however it is a moving target. Decades of research show that it changes in space and in time within a river, and is highly variable among different systems; however, these differences are not mechanistically understood. Recent researchers have proposed that the critical Shields stress is strongly dependent on the local configuration of the sediment bed [Frey and Church, 2011]. Critical Shields stress has been observed to change following sediment-transporting flood events in natural rivers [e.g., Turowski et al., 2011], while small-scale laboratory experiments have produced declining bed load transport rates associated with slow bed compaction [Charru et al., 2004]. However, no direct measurements have been made of the evolving bed structure under bed load transport, so the connection between granular controls and the threshold of motion remains uncertain. A perspective we adopt is that granular effects determine the critical Shields stress, while the fluid supplies a distribution of driving stresses. In order to isolate the granular effect, we undertake laminar bed load transport experiments using plastic beads sheared by a viscous oil in a small, annular flume. The fluid and beads are refractive index matched, and the fluid impregnated with a fluorescing powder. When illuminated with a planar laser sheet, we are able to image slices of the granular bed while also tracking the overlying sediment transport. We present the first results showing how bed load transport influences granular packing, and how changes in packing influence the threshold of motion to feed back on bed load transport rates. This effect may account for much of the variability observed in the threshold of motion in natural streams, and by extension offers a plausible explanation for hysteresis in bed load transport rates observed during floods. Charru, F., H. Mouilleron, and

  20. Continuous Security and Configuration Monitoring of HPC Clusters

    SciTech Connect

    Garcia-Lomeli, H. D.; Bertsch, A. D.; Fox, D. M.

    2015-05-08

    Continuous security and configuration monitoring of information systems has been a time consuming and laborious task for system administrators at the High Performance Computing (HPC) center. Prior to this project, system administrators had to manually check the settings of thousands of nodes, which required a significant number of hours rendering the old process ineffective and inefficient. This paper explains the application of Splunk Enterprise, a software agent, and a reporting tool in the development of a user application interface to track and report on critical system updates and security compliance status of HPC Clusters. In conjunction with other configuration management systems, the reporting tool is to provide continuous situational awareness to system administrators of the compliance state of information systems. Our approach consisted of the development, testing, and deployment of an agent to collect any arbitrary information across a massively distributed computing center, and organize that information into a human-readable format. Using Splunk Enterprise, this raw data was then gathered into a central repository and indexed for search, analysis, and correlation. Following acquisition and accumulation, the reporting tool generated and presented actionable information by filtering the data according to command line parameters passed at run time. Preliminary data showed results for over six thousand nodes. Further research and expansion of this tool could lead to the development of a series of agents to gather and report critical system parameters. However, in order to make use of the flexibility and resourcefulness of the reporting tool the agent must conform to specifications set forth in this paper. This project has simplified the way system administrators gather, analyze, and report on the configuration and security state of HPC clusters, maintaining ongoing situational awareness. Rather than querying each cluster independently, compliance checking