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Sample records for acr-1000 fuel bundle

  1. Proliferation Resistance Evaluation of ACR-1000 Fuel with Minor Actinides

    SciTech Connect

    Gray S. Chang

    2008-09-01

    The Global Nuclear Energy Partnership (GNEP) program is to significantly advance the science and technology of nuclear energy systems and to enhance the spent fuel proliferation resistance. It consists of both innovative nuclear reactors and innovative research in separation and transmutation. The merits of nuclear energy are high-density energy, with low environmental impacts (i.e. almost zero greenhouse gas emission). Planned efforts involve near-term and intermediate-term improvements in fuel utilization and recycling in current light water reactors (LWRs) as well as the longer-term development of new nuclear energy systems that offer much improved fuel utilization and proliferation resistance, along with continued advances in operational safety. For future advanced nuclear systems, minor actinides (MA) are viewed more as a resource to be recycled, and transmuted to less hazardous and possibly more useful forms, rather than simply disposed of as a waste stream in an expensive repository facility. MAs can play a much larger part in the design of advanced systems and fuel cycles, not only as additional sources of useful energy, but also as direct contributors to the reactivity control of the systems into which they are incorporated. In this work, an Advanced CANDU Reactor (ACR) fuel unit lattice cell model with 43 UO2 fuel rods will be used to investigate the effectiveness of a Minor Actinide Reduction Approach (MARA) for enhancing proliferation resistance and improving the fuel cycle performance. The main MARA objective is to increase the 238Pu / Pu isotope ratio by using the transuranic nuclides (237Np and 241Am) in the high burnup fuel and thereby increase the proliferation resistance even for a very low fuel burnup. As a result, MARA is a very effective approach to enhance the proliferation resistance for the on power refueling ACR system nuclear fuel. The MA transmutation characteristics at different MA loadings were compared and their impact on neutronics

  2. SEU43 fuel bundle shielding analysis during spent fuel transport

    SciTech Connect

    Margeanu, C. A.; Ilie, P.; Olteanu, G.

    2006-07-01

    The basic task accomplished by the shielding calculations in a nuclear safety analysis consist in radiation doses calculation, in order to prevent any risks both for personnel protection and impact on the environment during the spent fuel manipulation, transport and storage. The paper investigates the effects induced by fuel bundle geometry modifications on the CANDU SEU spent fuel shielding analysis during transport. For this study, different CANDU-SEU43 fuel bundle projects, developed in INR Pitesti, have been considered. The spent fuel characteristics will be obtained by means of ORIGEN-S code. In order to estimate the corresponding radiation doses for different measuring points the Monte Carlo MORSE-SGC code will be used. Both codes are included in ORNL's SCALE 5 programs package. A comparison between the considered SEU43 fuel bundle projects will be also provided, with CANDU standard fuel bundle taken as reference. (authors)

  3. Fuel bundle design for enhanced usage of plutonium fuel

    DOEpatents

    Reese, Anthony P.; Stachowski, Russell E.

    1995-01-01

    A nuclear fuel bundle includes a square array of fuel rods each having a concentration of enriched uranium and plutonium. Each rod of an interior array of the rods also has a concentration of gadolinium. The interior array of rods is surrounded by an exterior array of rods void of gadolinium. By this design, usage of plutonium in the nuclear reactor is enhanced.

  4. Fuel bundle design for enhanced usage of plutonium fuel

    DOEpatents

    Reese, A.P.; Stachowski, R.E.

    1995-08-08

    A nuclear fuel bundle includes a square array of fuel rods each having a concentration of enriched uranium and plutonium. Each rod of an interior array of the rods also has a concentration of gadolinium. The interior array of rods is surrounded by an exterior array of rods void of gadolinium. By this design, usage of plutonium in the nuclear reactor is enhanced. 10 figs.

  5. LWR fuel rod bundle behavior under severe fuel damage conditions

    SciTech Connect

    Kuczera, B. Hagen, S.; Hofmann, P.

    1988-01-01

    Light water reactor (LWR) safety research and development activities conducted at Kernforschungszentrum Karlsruhe have recently been reorganized with a concentrated mission under the LWR safety project group. The topics treated relate mainly to severe-accident analysis research and source term assessment as well as to source term mitigation measures. A major part of the investigations concerns the early phase of a severe core meltdown accident, specifically LWR rod assembly behavior under sever fuel damage (SFD) conditions. To determine the extent of fuel rod damage, including the relocation behavior of molten reaction products, damage propagation, time-dependent H{sub 2} generation from clad oxidation, and fragmentation of oxygen-embrittled materials during cooldown and quenching, extensive out-of-pile rod bundle experiments have been initiated in the new CORA test facility. The bundle parameters, such as rod dimensions, rod pitch, and grid spacer, can be adjusted to both pressurized water reactor (PWR) and boiling water reactor (BWR) conditions. Currently, the test program consists of 15 experiments in which the influence of Inconel grid spacer, (Ag,In,Cd)-absorber rods (PWR) and of B{sub 4}C control blades (BWR) on fuel damage initiation and damage propagation are being investigated for different boundary conditions. As of June 1988, four bundle tests had been successfully carried out for PWR accident conditions.

  6. Interconnection of bundled solid oxide fuel cells

    SciTech Connect

    Brown, Michael; Bessette, II, Norman F; Litka, Anthony F; Schmidt, Douglas S

    2014-01-14

    A system and method for electrically interconnecting a plurality of fuel cells to provide dense packing of the fuel cells. Each one of the plurality of fuel cells has a plurality of discrete electrical connection points along an outer surface. Electrical connections are made directly between the discrete electrical connection points of adjacent fuel cells so that the fuel cells can be packed more densely. Fuel cells have at least one outer electrode and at least one discrete interconnection to an inner electrode, wherein the outer electrode is one of a cathode and and anode and wherein the inner electrode is the other of the cathode and the anode. In tubular solid oxide fuel cells the discrete electrical connection points are spaced along the length of the fuel cell.

  7. The design of the DUPIC spent fuel bundle counter

    SciTech Connect

    Menlove, H.O.; Rinard, P.M.; Kroncke, K.E.; Lee, Y.G.

    1997-05-01

    A neutron coincidence detector had been designed to measure the amount of curium in the fuel bundles and associated process samples used in the direct use of plutonium in Canadian deuterium-uranium (CANDU) fuel cycle. All of the sample categories are highly radioactive from the fission products contained in the pressurized water reactor (PWR) spent fuel feed stock. Substantial shielding is required to protect the He-3 detectors from the intense gamma rays. The Monte Carlo neutron and photon calculational code has been used to design the counter with a uniform response profile along the length of the CANDU-type fuel bundle. Other samples, including cut PWR rods, process powder, waste, and finished rods, can be measured in the system. This report describes the performance characteristics of the counter and support electronics. 3 refs., 23 figs., 6 tabs.

  8. Hydraulic reinforcement of channel at lower tie-plate in BWR fuel bundle

    SciTech Connect

    Johansson, E.B.

    1989-12-26

    This patent describes an apparatus in a fuel bundle for confining fuel rods for the generation of steam in a steam water mixture passing interior of the fuel bundle. The fuel bundle includes: a lower tie-plate for supporting the fuel rods and permitting flow from the lower exterior portion of the fuel bundle into the interior portion of the fuel bundle; a plurality of fuel rods. The fuel rods supported on the lower tie-plate extending upwardly to and towards the upper portion of the fuel bundle for the generation of steam in a passing steam and water mixture interior of the fuel bundle; an upper tie-plate for maintaining the fuel rods in side-by-side relation and permitting a threaded connection between a plurality of the fuel rods with the threaded connection being at the upper and lower tie-plate. The upper tie-plate permitting escape of a steam water mixture from the top of the fuel bundle; a fuel bundle channel; and a labyrinth seal configured in the lower tie-plate.

  9. Two-dimensional computational modeling of sodium boiling in simulated LMFBR fuel-pin bundles

    SciTech Connect

    Dearing, J.F.

    1981-01-01

    Extensive sodium boiling tests have been carried out in two simulated LMFBR fuel pin bundles in the Thermal-Hydraulic Out-of-Reactor Safety (THORS) Facility at Oak Ridge National Laboratory. Experimental results from a 19-pin bundle (THORS Bundle 6A) have been previously reported, and experimental results from a 61-pin bundle (THORS Bundle 9) will be reported soon. The results discussed here are from the 19-pin bundle. Preliminary analysis has shown that the computational methods used and conclusions reached are equally valid for the 61-pin bundle, as well as the 19-pin in-reactor Sodium Loop Safety Facility (SLSF) W-1 experiment. The main result of THORS sodium boiling experimentation is that boiling behavior is determined by two-dimensional effects, i.e., the rates of mass, momentum and energy transfer in the direction perpendicular to the axes of the fuel pins.

  10. Cap assembly for a bundled tube fuel injector

    DOEpatents

    LeBegue, Jeffrey Scott; Melton, Patrick Benedict; Westmoreland, III, James Harold; Flanagan, James Scott

    2016-04-26

    A cap assembly for a bundled tube fuel injector includes an impingement plate and an aft plate that is disposed downstream from the impingement plate. The aft plate includes a forward side that is axially separated from an aft side. A tube passage extends through the impingement plate and the aft plate. A tube sleeve extends through the impingement plate within the tube passage towards the aft plate. The tube sleeve includes a flange at a forward end and an aft end that is axially separated from the forward end. A retention plate is positioned upstream from the impingement plate. A spring is disposed between the retention plate and the flange. The spring provides a force so as to maintain contact between at least a portion of the aft end of the tube sleeve and the forward side of the aft plate.

  11. Verification of the FBR fuel bundle-duct interaction analysis code BAMBOO by the out-of-pile bundle compression test with large diameter pins

    NASA Astrophysics Data System (ADS)

    Uwaba, Tomoyuki; Ito, Masahiro; Nemoto, Junichi; Ichikawa, Shoichi; Katsuyama, Kozo

    2014-09-01

    The BAMBOO computer code was verified by results for the out-of-pile bundle compression test with large diameter pin bundle deformation under the bundle-duct interaction (BDI) condition. The pin diameters of the examined test bundles were 8.5 mm and 10.4 mm, which are targeted as preliminary fuel pin diameters for the upgraded core of the prototype fast breeder reactor (FBR) and for demonstration and commercial FBRs studied in the FaCT project. In the bundle compression test, bundle cross-sectional views were obtained from X-ray computer tomography (CT) images and local parameters of bundle deformation such as pin-to-duct and pin-to-pin clearances were measured by CT image analyses. In the verification, calculation results of bundle deformation obtained by the BAMBOO code analyses were compared with the experimental results from the CT image analyses. The comparison showed that the BAMBOO code reasonably predicts deformation of large diameter pin bundles under the BDI condition by assuming that pin bowing and cladding oval distortion are the major deformation mechanisms, the same as in the case of small diameter pin bundles. In addition, the BAMBOO analysis results confirmed that cladding oval distortion effectively suppresses BDI in large diameter pin bundles as well as in small diameter pin bundles.

  12. Bundle duct interaction studies for fuel assemblies. [LMFBR

    SciTech Connect

    Hsia, H.T.S.; Kaplan, S.

    1981-06-01

    It is known that the wire-wrapped rods and duct in an LMFBR are undergoing a gradual structural distortion from the initially uniform geometry under the combined effects of thermal expansion and irradiation induced swelling and creep. These deformations have a significant effect on flow characteristics, thus causing changes in thermal behavior such as cladding temperature and temperature distribution within a bundle. The temperature distribution may further enhance or retard irradiation induced deformation of the bundle. This report summarizes the results of the continuing effort in investigating the bundle-duct interaction, focusing on the need for the large development plant.

  13. System for supporting a bundled tube fuel injector within a combustor

    DOEpatents

    LeBegue, Jeffrey Scott; Melton, Patrick Benedict; Westmoreland, III, James Harold; Flanagan, James Scott

    2016-06-21

    A combustor includes an end cover having an outer side and an inner side, an outer barrel having a forward end that is adjacent to the inner side of the end cover and an aft end that is axially spaced from the forward end. An inner barrel is at least partially disposed concentrically within the outer barrel and is fixedly connected to the outer barrel. A fluid conduit extends downstream from the end cover. A first bundled tube fuel injector segment is disposed concentrically within the inner barrel. The bundled tube fuel injector segment includes a fuel plenum that is in fluid communication with the fluid conduit and a plurality of parallel tubes that extend axially through the fuel plenum. The bundled tube fuel injector segment is fixedly connected to the inner barrel.

  14. Temperature Distributions in LMR Fuel Pin Bundles as Modeled by COBRA-IV-I

    NASA Astrophysics Data System (ADS)

    Wright, Steven A.; Stout, Sherry

    2005-02-01

    Most pin type reactor designs for space power or terrestrial applications group the fuel pins into a number of relatively large fuel pin bundles or subassemblies. Fuel bundles for terrestrial liquid metal fast breeders reactors typically use 217 - 271 pins per sub-assembly, while some SP100 designs use up to 331 pins in a central subassembly that was surrounded by partial assemblies. Because thermal creep is exponentially related to temperature, small changes in fuel pin cladding temperature can make large differences in the lifetime in a high temperature liquid metal reactor (LMR). This paper uses the COBRA-IV-I computer code to determine the temperature distribution within LMR fuel bundles. COBRA-IV-I uses the sub-channel analysis approach to determine the enthalpy (or temperature) and flow distribution in rod bundles for both steady-state and transient conditions. The COBRA code runs in only a few seconds and has been benchmarked and tested extensively over a wide range of flow conditions. In this report the flow and temperature distributions for two types of lithium cooled space reactor core designs were calculated. One design uses a very tight fuel pin packing that has a pitch to diameter ratio of 1.05 (small wire wrap with a diameter of 392 μm) as proposed in SP100. The other design uses a larger pitch to diameter ratio of 1.09 with a larger more conventional sized wire wrap diameter of 1 mm. The results of the COBRA pin bundle calculations show that the larger pitch-to-diameter fuel bundle designs are more tolerant to local flow blockages, and in addition they are less sensitive to mal-flow distributions that occur near the edges of the subassembly.

  15. Temperature Distributions in LMR Fuel Pin Bundles as Modeled by COBRA-IV-I

    SciTech Connect

    Wright, Steven A.; Stout, Sherry

    2005-02-06

    Most pin type reactor designs for space power or terrestrial applications group the fuel pins into a number of relatively large fuel pin bundles or subassemblies. Fuel bundles for terrestrial liquid metal fast breeders reactors typically use 217 - 271 pins per sub-assembly, while some SP100 designs use up to 331 pins in a central subassembly that was surrounded by partial assemblies. Because thermal creep is exponentially related to temperature, small changes in fuel pin cladding temperature can make large differences in the lifetime in a high temperature liquid metal reactor (LMR). This paper uses the COBRA-IV-I computer code to determine the temperature distribution within LMR fuel bundles. COBRA-IV-I uses the sub-channel analysis approach to determine the enthalpy (or temperature) and flow distribution in rod bundles for both steady-state and transient conditions. The COBRA code runs in only a few seconds and has been benchmarked and tested extensively over a wide range of flow conditions. In this report the flow and temperature distributions for two types of lithium cooled space reactor core designs were calculated. One design uses a very tight fuel pin packing that has a pitch to diameter ratio of 1.05 (small wire wrap with a diameter of 392 {mu}m) as proposed in SP100. The other design uses a larger pitch to diameter ratio of 1.09 with a larger more conventional sized wire wrap diameter of 1 mm. The results of the COBRA pin bundle calculations show that the larger pitch-to-diameter fuel bundle designs are more tolerant to local flow blockages, and in addition they are less sensitive to mal-flow distributions that occur near the edges of the subassembly.

  16. Results of international standard problem No. 36 severe fuel damage experiment of a VVER fuel bundle

    SciTech Connect

    Firnhaber, M.; Yegorova, L.; Brockmeier, U.

    1995-09-01

    International Standard Problems (ISP) organized by the OECD are defined as comparative exercises in which predictions with different computer codes for a given physical problem are compared with each other and with a carefully controlled experimental study. The main goal of ISP is to increase confidence in the validity and accuracy of analytical tools used in assessing the safety of nuclear installations. In addition, it enables the code user to gain experience and to improve his competence. This paper presents the results and assessment of ISP No. 36, which deals with the early core degradation phase during an unmitigated severe LWR accident in a Russian type VVER. Representatives of 17 organizations participated in the ISP using the codes ATHLET-CD, ICARE2, KESS-III, MELCOR, SCDAP/RELAP5 and RAPTA. Some participants performed several calculations with different codes. As experimental basis the severe fuel damage experiment CORA-W2 was selected. The main phenomena investigated are thermal behavior of fuel rods, onset of temperature escalation, material behavior and hydrogen generation. In general, the calculations give the right tendency of the experimental results for the thermal behavior, the hydrogen generation and, partly, for the material behavior. However, some calculations deviate in important quantities - e.g. some material behavior data - showing remarkable discrepancies between each other and from the experiments. The temperature history of the bundle up to the beginning of significant oxidation was calculated quite well. Deviations seem to be related to the overall heat balance. Since the material behavior of the bundle is to a great extent influenced by the cladding failure criteria a more realistic cladding failure model should be developed at least for the detailed, mechanistic codes. Regarding the material behavior and flow blockage some models for the material interaction as well as for relocation and refreezing requires further improvement.

  17. Rod bundle thermal-hydraulic and melt progression analysis of CORA severe fuel damage experiments

    SciTech Connect

    Suh, K.Y. )

    1994-04-01

    An integral, fast-running computational model is developed to simulate the thermal-hydraulic and melt progression behavior in a nuclear reactor rod bundle under severe fuel damage conditions. This consists of the submodels for calculating steaming from the core, hydrogen formation, heat transfer in and out of the core, cooling from core spray or injection, and, most importantly, fuel melting, relocation, and freezing with chemical interactions taking place among the material constituents in a degrading core. The integral model is applied to three German severe fuel damage tests to analyze the core thermal and melt behavior: CORA-16 (18-rod bundle and slow cooling), CORA-17 (18-rod bundle and quenching), and CORA-18 (48-rod bundle and slow cooling). Results of the temperature response of the fuel rods, the channel box, and the absorber blade; hydrogen generation from the fuel rod and the channel box; and core material eutectic formation, melt relocation, and blockage formation are discussed. Reasonable agreement is observed for component temperatures at midelevation where prediction and measurement uncertainties are minimal. However, discrepancies or uncertainties are noticed for hydrogen generation and core-melt progression. The experimentally observed peak generation of hydrogen upon reflooding is not able to be reproduced, and the total amount generated is generally underpredicted primarily because of the early relocation of the Zircaloy fuel channel box and cladding. Also, difficulties are encountered in the process of assessing the core-melt formation and the relocation model because of either modeling uncertainties or a lack of definitive metallurgical data as a function of time throughout the transient.

  18. Evaluation of the magnitude and effects of bundle duct interaction in fuel assemblies at developmental plant conditions

    SciTech Connect

    Serell, D.C.; Kaplan, S.

    1980-09-01

    Purpose of this evaluation is to estimate the magnitude and effects of irradiation and creep induced fuel bundle deformations in the developmental plant. This report focuses on the trends of the results and the ability of present models to evaluate the assembly temperatures in the presence of bundle deformation. Although this analysis focuses on the developmental plant, the conclusions are applicable to LMFBR fuel assemblies in general if they have wire spacers.

  19. A Mechanistic Approach for the Prediction of Critical Power in BWR Fuel Bundles

    NASA Astrophysics Data System (ADS)

    Chandraker, Dinesh Kumar; Vijayan, Pallipattu Krishnan; Sinha, Ratan Kumar; Aritomi, Masanori

    The critical power corresponding to the Critical Heat Flux (CHF) or dryout condition is an important design parameter for the evaluation of safety margins in a nuclear fuel bundle. The empirical approaches for the prediction of CHF in a rod bundle are highly geometric specific and proprietary in nature. The critical power experiments are very expensive and technically challenging owing to the stringent simulation requirements for the rod bundle tests involving radial and axial power profiles. In view of this, the mechanistic approach has gained momentum in the thermal hydraulic community. The Liquid Film Dryout (LFD) in an annular flow is the mechanism of CHF under BWR conditions and the dryout modeling has been found to predict the CHF quite accurately for a tubular geometry. The successful extension of the mechanistic model of dryout to the rod bundle application is vital for the evaluation of critical power in the rod bundle. The present work proposes the uniform film flow approach around the rod by analyzing individual film of the subchannel bounded by rods with different heat fluxes resulting in different film flow rates around a rod and subsequently distributing the varying film flow rates of a rod to arrive at the uniform film flow rate as it has been found that the liquid film has a strong tendency to be uniform around the rod. The FIDOM-Rod code developed for the dryout prediction in BWR assemblies provides detailed solution of the multiple liquid films in a subchannel. The approach of uniform film flow rate around the rod simplifies the liquid film cross flow modeling and was found to provide dryout prediction with a good accuracy when compared with the experimental data of 16, 19 and 37 rod bundles under BWR conditions. The critical power has been predicted for a newly designed 54 rod bundle of the Advanced Heavy Water Reactor (AHWR). The selected constitutive models for the droplet entrainment and deposition rates validated for the dryout in tube were

  20. Numerical Study on Influence of Cross Flow on Rewetting of AHWR Fuel Bundle

    PubMed Central

    Kumar, Mithilesh; Mukhopadhyay, D.; Ghosh, A. K.; Kumar, Ravi

    2014-01-01

    Numerical study on AHWR fuel bundle has been carried out to assess influence of circumferential and cross flow rewetting on the conduction heat transfer. The AHWR fuel bundle quenching under accident condition is designed primarily with radial jets at several axial locations. A 3D (r, θ, z) transient conduction fuel pin model has been developed to carry out the study with a finite difference method (FDM) technique with alternating direction implicit (ADI) scheme. The single pin has been considered to study effect of circumferential conduction and multipins have been considered to study the influence of cross flow. Both analyses are carried out with the same fluid temperature and heat transfer coefficients as boundary conditions. It has been found from the analyses that, for radial jet, the circumferential conduction is significant and due to influence of overall cross flow the reductions in fuel temperature in the same quench plane in different rings are different with same initial surface temperature. Influence of cross flow on rewetting is found to be very significant. Outer fuel pins rewetting time is higher than inner. PMID:24672341

  1. Calculation of the Local Neutronic Parameters for CANDU Fuel Bundles Using Transport Methods

    SciTech Connect

    Balaceanu, Victoria; Rizoiu, Andrei; Hristea, Viorel

    2006-07-01

    For a realistic neutronic evaluation of the CANDU reactor core it is important to accurately perform the local neutronic parameters (i.e. multigroup macroscopic cross sections for the core materials) calculation. This means using codes that allow a good geometric representation of the CANDU fuel bundle and then solving the transport equation. The paper reported here intends to study in detail the local behavior for two types of CANDU fuel, NU{sub 3}7 (Natural Uranium, 37 elements) and SEU{sub 4}3 (Slightly Enriched Uranium, 43 elements, with 1.1 wt% enrichment). The considered fuel types represent fresh and used bundles. The two types of CANDU super-cells are reference NU{sub 3}7, perturbed NU{sub 3}7, reference SEU{sub 4}3 and perturbed SEU{sub 4}3. The perturbed super-cells contain a Mechanical Control Absorber (a very strong reactivity device). For reaching the proposed objective a methodology is used based on WIMS and PIJXYZ codes. WIMS is a standard lattice-cell code, based on transport theory and it is used for producing fuel cell multigroup macroscopic cross sections. For obtaining the fine local neutronic parameters in the CANDU super-cells (k-eff values, local MCA reactivity worth, flux distributions and reaction rates), the PIJXYZ code is used. PIJXYZ is a 3D integral transport code using the first collision probability method and it has been developed for CANDU cell geometry. It is consistent with WIMS lattice-cell calculations and allows a good geometrical representation of the CANDU bundle in three dimensions. The analysis of the neutronic parameters consists of comparing the obtained results with the similar results calculated with the DRAGON code. This comparison shows a good agreement between these results. (authors)

  2. Combustor having mixing tube bundle with baffle arrangement for directing fuel

    DOEpatents

    Hughes, Michael John; McConnaughhay, Johnie Franklin

    2016-08-23

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface, and a plurality of tubes extend from the upstream surface through the downstream surface to provide fluid communication through the tube bundle. A barrier extends radially inside the tube bundle between the upstream and downstream surfaces, and a baffle extends axially inside the tube bundle between the upstream surface and the barrier.

  3. Heat Transfer Enhancement By Three-Dimensional Surface Roughness Technique In Nuclear Fuel Rod Bundles

    NASA Astrophysics Data System (ADS)

    Najeeb, Umair

    This thesis experimentally investigates the enhancement of single-phase heat transfer, frictional loss and pressure drop characteristics in a Single Heater Element Loop Tester (SHELT). The heater element simulates a single fuel rod for Pressurized Nuclear reactor. In this experimental investigation, the effect of the outer surface roughness of a simulated nuclear rod bundle was studied. The outer surface of a simulated fuel rod was created with a three-dimensional (Diamond-shaped blocks) surface roughness. The angle of corrugation for each diamond was 45 degrees. The length of each side of a diamond block is 1 mm. The depth of each diamond block was 0.3 mm. The pitch of the pattern was 1.614 mm. The simulated fuel rod had an outside diameter of 9.5 mm and wall thickness of 1.5 mm and was placed in a test-section made of 38.1 mm inner diameter, wall thickness 6.35 mm aluminum pipe. The Simulated fuel rod was made of Nickel 200 and Inconel 625 materials. The fuel rod was connected to 10 KW DC power supply. The Inconel 625 material of the rod with an electrical resistance of 32.3 kO was used to generate heat inside the test-section. The heat energy dissipated from the Inconel tube due to the flow of electrical current flows into the working fluid across the rod at constant heat flux conditions. The DI water was employed as working fluid for this experimental investigation. The temperature and pressure readings for both smooth and rough regions of the fuel rod were recorded and compared later to find enhancement in heat transfer coefficient and increment in the pressure drops. Tests were conducted for Reynold's Numbers ranging from 10e4 to 10e5. Enhancement in heat transfer coefficient at all Re was recorded. The maximum heat transfer co-efficient enhancement recorded was 86% at Re = 4.18e5. It was also observed that the pressure drop and friction factor increased by 14.7% due to the increased surface roughness.

  4. Fuel cell integral bundle assembly including ceramic open end seal and vertical and horizontal thermal expansion control

    SciTech Connect

    Zafred, Paolo R.; Gillett, James E.

    2012-04-24

    A plurality of integral bundle assemblies contain a top portion with an inlet fuel plenum and a bottom portion containing a base support, the base supports a dense, ceramic air exhaust manifold having four supporting legs, the manifold is below and connects to air feed tubes located in a recuperator zone, the air feed tubes passing into the center of inverted, tubular, elongated, hollow electrically connected solid oxide fuel cells having an open end above a combustion zone into which the air feed tubes pass and a closed end near the inlet fuel plenum, where the open end of the fuel cells rest upon and within a separate combination ceramic seal and bundle support contained in a ceramic support casting, where at least one flexible cushion ceramic band seal located between the recuperator and fuel cells protects and controls horizontal thermal expansion, and where the fuel cells operate in the fuel cell mode and where the base support and bottom ceramic air exhaust manifolds carry from 85% to all of the weight of the generator.

  5. Development of a Fast Breeder Reactor Fuel Bundle Deformation Analysis Code - BAMBOO: Development of a Pin Dispersion Model and Verification by the Out-of-Pile Compression Test

    SciTech Connect

    Uwaba, Tomoyuki; Ito, Masahiro; Ukai, Shigeharu

    2004-02-15

    To analyze the wire-wrapped fast breeder reactor fuel pin bundle deformation under bundle/duct interaction conditions, the Japan Nuclear Cycle Development Institute has developed the BAMBOO computer code. This code uses the three-dimensional beam element to calculate fuel pin bowing and cladding oval distortion as the primary deformation mechanisms in a fuel pin bundle. The pin dispersion, which is disarrangement of pins in a bundle and would occur during irradiation, was modeled in this code to evaluate its effect on bundle deformation. By applying the contact analysis method commonly used in the finite element method, this model considers the contact conditions at various axial positions as well as the nodal points and can analyze the irregular arrangement of fuel pins with the deviation of the wire configuration.The dispersion model was introduced in the BAMBOO code and verified by using the results of the out-of-pile compression test of the bundle, where the dispersion was caused by the deviation of the wire position. And the effect of the dispersion on the bundle deformation was evaluated based on the analysis results of the code.

  6. Development of a Fast Breeder Reactor Fuel Bundle-Duct Interaction Analysis Code - BAMBOO: Analysis Model and Validation by the Out-of-Pile Compression Test

    SciTech Connect

    Uwaba, Tomoyuki; Tanaka, Kosuke

    2001-10-15

    To analyze the wire-wrapped fast breeder reactor (FBR) fuel pin bundle deformation under bundle-duct interaction (BDI) conditions, the Japan Nuclear Cycle Development Institute has developed the BAMBOO computer code. A three-dimensional beam element model is used in this code to calculate fuel pin bowing and cladding oval distortion, which are the dominant deformation mechanisms in a fuel pin bundle. In this work, the property of the cladding oval distortion considering the wire-pitch was evaluated experimentally and introduced in the code analysis.The BAMBOO code was validated in this study by using an out-of-pile bundle compression testing apparatus and comparing these results with the code results. It is concluded that BAMBOO reasonably predicts the pin-to-duct clearances in the compression tests by treating the cladding oval distortion as the suppression mechanism to BDI.

  7. Electrolytic/fuel cell bundles and systems including a current collector in communication with an electrode thereof

    DOEpatents

    Hawkes, Grant L.; Herring, James S.; Stoots, Carl M.; O& #x27; Brien, James E.

    2013-03-05

    Electrolytic/fuel cell bundles and systems including such bundles include an electrically conductive current collector in communication with an anode or a cathode of each of a plurality of cells. A cross-sectional area of the current collector may vary in a direction generally parallel to a general direction of current flow through the current collector. The current collector may include a porous monolithic structure. At least one cell of the plurality of cells may include a current collector that surrounds an outer electrode of the cell and has at least six substantially planar exterior surfaces. The planar surfaces may extend along a length of the cell, and may abut against a substantially planar surface of a current collector of an adjacent cell. Methods for generating electricity and for performing electrolysis include flowing current through a conductive current collector having a varying cross-sectional area.

  8. Development of an internally cooled annular fuel bundle for pressurized heavy water reactors

    SciTech Connect

    Hamilton, H.; Armstrong, J.; Kittmer, A.; Zhuchkova, A.; Xu, R.; Hyland, B.; King, M.; Nava-Dominguez, A.; Livingstone, S.; Bergeron, A.

    2013-07-01

    A number of preliminary studies have been conducted at Atomic Energy of Canada Limited to explore the potential of using internally cooled annular fuel (ICAF) in CANDU reactors including finite element thermo-mechanical modelling, reactor physics, thermal hydraulics, fabrication and mechanical design. The most compelling argument for this design compared to the conventional solid-rod design is the significant reduction in maximum fuel temperature for equivalent LERs (linear element ratings). This feature presents the potential for power up-rating or higher burnup and a decreased defect probability due to in-core power increases. The thermal-mechanical evaluation confirmed the significant reduction in maximum fuel temperatures for ICAF fuel compared to solid-rod fuel for equivalent LER. The maximum fuel temperature increase as a function of LER increase is also significantly less for ICAF fuel. As a result, the sheath stress induced by an equivalent power increase is approximately six times less for ICAF fuel than solid-rod fuel. This suggests that the power-increase thresholds to failure (due to stress-corrosion cracking) for ICAF fuel should be well above those for solid-rod fuel, providing improvement in operation flexibility and safety.

  9. Irradiation performance of long-rod duplex fuel-pellet bundle test - LDR test (AWBA Development Program)

    SciTech Connect

    Waldman, L.A.; Sphar, C.D.; Alff, T.H.

    1982-04-01

    The Long Duplex Rod (LDR) test is a five-rod bundle irradiation test of 0.30-inch diameter, 8-foot long, Zircaloy-clad rods containing duplex fuel pellets. These pellets include fissile material in an outer annulus surrounding fertile material in an inner cylindrical core. The rods are axially supported by top or bottom base plates and are laterally supported by an AM-350 stainless steel grid system. Design of the test, which includes duplex pellet annuli of three different compositions (UO/sub 2/, ZrO/sub 2/-UO/sub 2/-CaO, and ThO/sub 2/-UO/sub 2/), is described; and results of nondestructive examination after operation at peak linear power output of 9 to 18 Kw/ft to a peak depletion of 15 x 10/sup 20/ fissions/cm/sup 3/ of compartment (6.0 x 10/sup 4/ MWD/Tonne U + Th), or 30 x 10/sup 20/ fissions/cm/sup 3/ of fuel annulus volume (1.2 x 10/sup 5/ MWD/Tonne U + Th), are presented. It is concluded that performance capability of the duplex pellets is satisfactory for use in prebreeder reactor cores.

  10. Fuel bundle assembly machine

    SciTech Connect

    Tunnell, G.W.; Schoenig, F.C. Jr.; Mc Lemore, D.R.; Patterson, R.G.

    1987-03-17

    An apparatus is described for placing elongate objects of substantially identical size and shape in a coordinate array in a support structure. The objects are parallel and mutually spaced from each other and each object occupies a designated coordinate position as determined by an identifying code carried by each object; the apparatus comprising: a queuing station for holding the plurality of objects; means for selectively removing the objects from the queuing station one at a time; means for reading the code on the removed objects; means responsive to each code read for positioning the corresponding object in horizontal and vertical alignment with the coordinate position; transport means for longitudinally moving each of the aligned objects into the two-dimensional coordinate position; and control means responsive to the presence of each object in a plurality of critical positions during its transfer between the queuing station and the coordinate position for timing and confirming the proper operation of the apparatus.

  11. COBRA-IV PC: A personal computer version of COBRA-IV-I for thermal-hydraulic analysis of rod bundle nuclear fuel elements and cores

    SciTech Connect

    Webb, B.J.

    1988-01-01

    COBRA-IV PC is a modified version of COBRA-IV-I, adapted for use with most IBM PC and PC-compatible desktop computers. Like COBRA-IV-I, COBRA-IV PC uses the subchannel analysis approach to determine the enthalpy and flow distribution in rod bundles for both steady-state and transient conditions. The steady-state and transient solution schemes used in COBRA-IIIC are still available in COBRA-IV PC as the implicit solution scheme option. An explicit solution scheme is also available, allowing the calculation of severe transients involving flow reversals, recirculations, expulsions, and reentry flows, with a pressure or flow boundary condition specified. In addition, several modifications have been incorporated into COBRA-IV PC to allow the code to run on the PC. These include a reduction in the array dimensions, the removal of the dump and restart options, and the inclusion of several code modifications by Oregon State University, most notably, a critical heat flux correlation for boiling water reactor fuel and a new solution scheme for cross-flow distribution calculations. 7 refs., 8 figs., 1 tab.

  12. His bundle electrography

    MedlinePlus

    ... can be given medicines during the test. Electrocardiogram (ECG) leads are placed on your arms and legs. ... HBE; His bundle recording; Electrogram - His bundle Images ECG References Miller JM, Zipes DP. Diagnosis of cardiac ...

  13. A two-phase flow regime map for a MAPLE-type nuclear research reactor fuel channel: Effect of hexagonal finned bundle

    SciTech Connect

    Harvel, G.D.; Chang, J.S.; Krishnan, V.S.

    1997-05-01

    A two-phase flow regime map is developed experimentally and theoretically for a vertical hexagonal flow channel with and without a 36-finned rod hexagonal bundle. This type of flow channel is of interest to MAPLE-type nuclear research reactors. The flow regime maps are determined by visual observations and observation of waveforms shown by a capacitance-type void fraction meter. The experimental results show that the inclusion of the finned hexagonal bundle shifts the flow regime transition boundaries toward higher water flow rates. Existing flow regime maps based on pipe flow require slight modifications when applied to the hexagonal flow channel with and without a MAPLE-type finned hexagonal bundle. The proposed theoretical model agrees well with experimental results.

  14. Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Progress report

    SciTech Connect

    Todreas, N.E.; Golay, M.W.; Wold, L.

    1981-02-01

    Four tasks are reported on: bundle geometry (wrapped and bare rods), subchannel geometry (bare rods), LMFBR outlet plenum flow mixing, and theoretical determination of local temperature fields in LMFBR fuel rod bundles. (DLC)

  15. Estimation of clearance potential index and hazard factors of Candu fuel bundle and its validation based on the measurements of radioisotopes inventories from Pickering reactor fuel

    SciTech Connect

    Pavelescu, Alexandru Octavian; Tinti, Renato; Voukelatou, Konstantina; Cepraga, Dan Gabriel

    2007-07-01

    This paper is related to the clearance potential levels, ingestion and inhalation hazard factors of the spent nuclear fuel and radioactive wastes. This study required a complex activity that consisted of more steps such as: the acquisition, setting up, validation and application of procedures, codes and libraries. The paper reflects the validation stage of this study. Its objective was to compare the measured inventories of selected actinide and fission products radionuclides in an element from the Pickering Candu reactor with the inventories predicted using a recent version of the SCALE 5/ORIGEN-ARP code coupled with the time dependent cross sections library for the Candu 28 reactor (produced by the sequence SCALE4.4a/SAS2H and SCALE4.4a/ORIGEN-S). In this way, the procedures, the codes and the libraries for the characterization of radioactive material in terns of radioactive inventories, clearance, and biological hazard factors could be qualified and validated, in support of the safety management of the radioactive wastes. (authors)

  16. German bundle shear - cold test results

    SciTech Connect

    Kunze, P.

    1986-01-01

    In the planned Federal Republic of Germany (FRG) reprocessing plant, the mechanical decladding of the fuel elements will be done with a bundle shear. This shear was designed and built with Thyssen Henschel by adapting the experiences of the Wiederaufarbeitungsanlage Karlsruhe (WAK), the FRG reprocessing pilot plant. The tests included boiling water reactor (BWR) and pressurized water reactor (PWR) dummy elements filled with porcelain as well as steel fuel rod simulators. During the test period with prototype bundle shear, some technical improvements have been found that refer both to operating conditions and to remote handling. In 1987 the acceptance tests will be run.

  17. Fuel transfer system

    DOEpatents

    Townsend, Harold E.; Barbanti, Giancarlo

    1994-01-01

    A nuclear fuel bundle fuel transfer system includes a transfer pool containing water at a level above a reactor core. A fuel transfer machine therein includes a carriage disposed in the transfer pool and under the water for transporting fuel bundles. The carriage is selectively movable through the water in the transfer pool and individual fuel bundles are carried vertically in the carriage. In a preferred embodiment, a first movable bridge is disposed over an upper pool containing the reactor core, and a second movable bridge is disposed over a fuel storage pool, with the transfer pool being disposed therebetween. A fuel bundle may be moved by the first bridge from the reactor core and loaded into the carriage which transports the fuel bundle to the second bridge which picks up the fuel bundle and carries it to the fuel storage pool.

  18. Fuel transfer system

    DOEpatents

    Townsend, H.E.; Barbanti, G.

    1994-03-01

    A nuclear fuel bundle fuel transfer system includes a transfer pool containing water at a level above a reactor core. A fuel transfer machine therein includes a carriage disposed in the transfer pool and under the water for transporting fuel bundles. The carriage is selectively movable through the water in the transfer pool and individual fuel bundles are carried vertically in the carriage. In a preferred embodiment, a first movable bridge is disposed over an upper pool containing the reactor core, and a second movable bridge is disposed over a fuel storage pool, with the transfer pool being disposed therebetween. A fuel bundle may be moved by the first bridge from the reactor core and loaded into the carriage which transports the fuel bundle to the second bridge which picks up the fuel bundle and carries it to the fuel storage pool. 6 figures.

  19. Fiber bundle endocytoscopy

    PubMed Central

    Hughes, Michael; Chang, Tou Pin; Yang, Guang-Zhong

    2013-01-01

    Endocytoscopy is an optical biopsy technique which uses a miniaturized camera to capture white light microscopy images through an endoscope. We have developed an alternative design that instead relays images to an external camera via a coherent fiber bundle. In this paper we characterize the device and demonstrate microscopy of porcine tissue ex vivo. One advantage of our approach is the ease with which other bundle-compatible imaging modalities can be deployed simultaneously. We show this by acquiring quasi-simultaneous endocytoscopy and fluorescence confocal endomicroscopy images through a single fiber bundle. This opens up possibilities for multi-modal endomicroscopy, combining white light and fluorescence imaging. PMID:24409380

  20. MEGARA fiber bundles

    NASA Astrophysics Data System (ADS)

    Pérez-Calpena, A.; García-Vargas, María. Luisa; Arrillaga, X.; Gil de Paz, A.; Sánchez-Blanco, E.; Martínez-Delgado, I.; Carrera, M. A.; Gallego, J.; Carrasco, E.; Sánchez-Moreno, F. M.; Iglesias-Páramo, J.

    2014-07-01

    MEGARA (Multi Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the 10.4-m Gran Telescopio CANARIAS (GTC). MEGARA has three different fiber bundles, the Large Central Bundle covering 12.5 arcsec x 11.3 arcsec on sky, the Small Compact Bundle, of 8.5 arcsec x 6.7 arcsec, and a Fiber MOS positioner system that is able to place up to 100 mini-bundles with 7 fibers each in MOS configuration within a 3.5 arcmin x 3.5 arcmin FOV. The MEGARA focal plane subsystems are located at one of the GTC Folded Cassegrain focal stations. A field lens provides a telecentric focal plane, where the fibers are located. Micro-lenses arrays couple the telescope beam to the collimator focal ratio at the entrance of the fibers. Finally, the fibers, organized in bundles conducted the light from the focal plane to the pseudo-slit plates at the entrance of the MEGARA spectrograph, which shall be located at one of the Nasmyth platforms. This article also summarizes the prototypes already done and describes the set-up that shall be used to integrate fibers and micro-lens and characterize the fiber bundles.

  1. Bundle Binding in Polyelectrolyte Solutions

    SciTech Connect

    Stevens, M.J.

    1999-01-21

    Stiff polyelectrolytes are found to spontaneously form oriented bundles. Conditions under which bundling occurs are found. Molecular dynamics simulations show that divalent counterions are necessary, and the chains must be sufficiently long and stiff. No aggregation occurs for monovalent counterions. For flexible or short chains aggregation occurs, but bundle formation does not. Due to dynamical constraints the systems tend to order into a network of connected bundles, not a single bundle.

  2. Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Progress report, March 1, 1980-May 31, 1980

    SciTech Connect

    Todreas, N.E.; Golay, M.W.; Wolf, L.

    1980-01-01

    Experimental and theoretical work is reported on four tasks: bundle geometry (wrapped and bare rods), subchannel geometry (bare rods), LMFBR outlet plenum flow mixing, and theoretical local temperature files in LMFBR fuel rod bundles. (DLC)

  3. Dynamics of flagellar bundling

    NASA Astrophysics Data System (ADS)

    Janssen, Pieter; Graham, Michael

    2010-11-01

    Flagella are long thin appendages of microscopic organisms used for propulsion in low-Reynolds environments. For E. coli the flagella are driven by a molecular motor, which rotates the flagella in a counter-clockwise motion (CCM). When in a forward swimming motion, all flagella bundle up. If a motor reverses rotation direction, the flagella unbundle and the cell makes a tumbling motion. When all motors turn in the same CC direction again, the flagella bundle up, and forward swimming continues. To investigate the bundling, we consider two flexible helices next to each other, as well as several flagella attached to a spherical body. Each helix is modeled as several prolate spheroids connected at the tips by springs. For hydrodynamic interactions, we consider the flagella to made up of point forces, while the finite size of the body is incorporated via Fax'en's laws. We show that synchronization occurs quickly relative to the bundling process. For flagella next to each other, the initial deflection is generated by rotlet interactions generated by the rotating helices. At longer times, simulations show the flagella only wrap once around each other, but only for flagella that are closer than about 4 helix radii. Finally, we show a run-and-tumble motion of the body with attached flagella.

  4. Bundled monocapillary optics

    DOEpatents

    Hirsch, Gregory

    2002-01-01

    A plurality of glass or metal wires are precisely etched to form the desired shape of the individual channels of the final polycapillary optic. This shape is created by carefully controlling the withdrawal speed of a group of wires from an etchant bath. The etched wires undergo a subsequent operation to create an extremely smooth surface. This surface is coated with a layer of material which is selected to maximize the reflectivity of the radiation being used. This reflective surface may be a single layer of material, or a multilayer coating for optimizing the reflectivity in a narrower wavelength interval. The collection of individual wires is assembled into a close-packed multi-wire bundle, and the wires are bonded together in a manner which preserves the close-pack configuration, irrespective of the local wire diameter. The initial wires are then removed by either a chemical etching procedure or mechanical force. In the case of chemical etching, the bundle is generally segmented by cutting a series of etching slots. Prior to removing the wire, the capillary array is typically bonded to a support substrate. The result of the process is a bundle of precisely oriented radiation-reflecting hollow channels. The capillary optic is used for efficiently collecting and redirecting the radiation from a source of radiation which could be the anode of an x-ray tube, a plasma source, the fluorescent radiation from an electron microprobe, a synchrotron radiation source, a reactor or spallation source of neutrons, or some other source.

  5. [Masquerading bundle branch block].

    PubMed

    Kukla, Piotr; Baranchuk, Adrian; Jastrzębski, Marek; Bryniarski, Leszek

    2014-01-01

    We here describe a surface 12-lead electrocardiogram (ECG) of a 72-year-old female with a prior history of breast cancer and chemotherapy-induced cardiomyopathy. An echocardiogram revealed left ventricular dysfunction, ejection fraction of 23%, with mild enlarged left ventricle. The 12-lead ECG showed atrial fibrillation with a mean heart rate of about 100 bpm, QRS duration 160 ms, QT interval 400 ms, right bundle branch block (RBBB) and left anterior fascicular block (LAFB). The combination of RBBB features in the precordial leads and LAFB features in the limb leads is known as ''masquerading bundle branch block''. In most cases of RBBB and LAFB, the QRS axis deviation is located between - 80 to -120 degrees. Rarely, when predominant left ventricular forces are present, the QRS axis deviation is near about -90 degrees, turning the pattern into an atypical form. In a situation of RBBB associated with LAFB, the S wave can be absent or very small in lead I. Such a situation is the result of not only purely LAFB but also with left ventricular hypertrophy and/or focal block due to scar (extensive anterior myocardial infarction) or fibrosis (cardiomyopathy). Sometimes, this specific ECG pattern is mistaken for LBBB. RBBB with LAFB may imitate LBBB either in the limb leads (known as 'standard masquerading' - absence of S wave in lead I), or in the precordial leads (called 'precordial masquerading' - absence of S wave in leads V₅ and V₆). Our ECG showed both these types of masquerading bundle branch block - absence of S wave in lead I and in leads V₅ and V₆. PMID:24469750

  6. Monad constructions of omalous bundles

    NASA Astrophysics Data System (ADS)

    Henni, Abdelmoubine Amar; Jardim, Marcos

    2013-12-01

    We consider a particular class of holomorphic vector bundles relevant for supersymmetric string theory, called omalous, over nonsingular projective varieties. We use monads to construct examples of such bundles over 3-fold hypersurfaces in P4, complete intersection Calabi-Yau manifolds in Pk, blow-ups of P2 at n distinct points, and products Pm×Pn.

  7. Bundle Security Protocol for ION

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.; Birrane, Edward J.; Krupiarz, Christopher

    2011-01-01

    This software implements bundle authentication, conforming to the Delay-Tolerant Networking (DTN) Internet Draft on Bundle Security Protocol (BSP), for the Interplanetary Overlay Network (ION) implementation of DTN. This is the only implementation of BSP that is integrated with ION.

  8. Fiber bundle phase conjugate mirror

    SciTech Connect

    Ward, Benjamin G.

    2012-05-01

    An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

  9. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: (1) 3.7 amps per wire; (2) bundle of 15 or more wires; (3) 70 C environment: and (4) vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  10. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1999-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 degree C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: (1) 3.7 amps per wire (2) bundle of 15 or more wires (3) 70 C environment (4) vacuum of 10(exp -5) torr or less To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  11. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: 3.7 amps per wire, bundle of 15 or more wires, 70 C environment, and vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  12. Evaluating big deal journal bundles.

    PubMed

    Bergstrom, Theodore C; Courant, Paul N; McAfee, R Preston; Williams, Michael A

    2014-07-01

    Large commercial publishers sell bundled online subscriptions to their entire list of academic journals at prices significantly lower than the sum of their á la carte prices. Bundle prices differ drastically between institutions, but they are not publicly posted. The data that we have collected enable us to compare the bundle prices charged by commercial publishers with those of nonprofit societies and to examine the types of price discrimination practiced by commercial and nonprofit journal publishers. This information is of interest to economists who study monopolist pricing, librarians interested in making efficient use of library budgets, and scholars who are interested in the availability of the work that they publish. PMID:24979785

  13. Evaluating big deal journal bundles

    PubMed Central

    Bergstrom, Theodore C.; Courant, Paul N.; McAfee, R. Preston; Williams, Michael A.

    2014-01-01

    Large commercial publishers sell bundled online subscriptions to their entire list of academic journals at prices significantly lower than the sum of their á la carte prices. Bundle prices differ drastically between institutions, but they are not publicly posted. The data that we have collected enable us to compare the bundle prices charged by commercial publishers with those of nonprofit societies and to examine the types of price discrimination practiced by commercial and nonprofit journal publishers. This information is of interest to economists who study monopolist pricing, librarians interested in making efficient use of library budgets, and scholars who are interested in the availability of the work that they publish. PMID:24979785

  14. Tube bundle system

    PubMed Central

    Marchewka, W.; Mohamed, K.; Addis, J.; Karnack, F.

    2015-01-01

    A tube bundle system (TBS) is a mechanical system for continuously drawing gas samples through tubes from multiple monitoring points located in an underground coal mine. The gas samples are drawn via vacuum pump to the surface and are typically analyzed for oxygen, methane, carbon dioxide and carbon monoxide. Results of the gas analyses are displayed and recorded for further analysis. Trends in the composition of the mine atmosphere, such as increasing methane or carbon monoxide concentration, can be detected early, permitting rapid intervention that prevents problems, such as a potentially explosive atmosphere behind seals, fire or spontaneous combustion. TBS is a well-developed technology and has been used in coal mines around the world for more than 50 years. Most longwall coal mines in Australia deploy a TBS, usually with 30 to 40 monitoring points as part of their atmospheric monitoring. The primary uses of a TBS are detecting spontaneous combustion and maintaining sealed areas inert. The TBS might also provide mine atmosphere gas composition data after a catastrophe occurs in an underground mine, if the sampling tubes are not damaged. TBSs are not an alternative to statutory gas and ventilation airflow monitoring by electronic sensors or people; rather, they are an option to consider in an overall mine atmosphere monitoring strategy. This paper describes the hardware, software and operation of a TBS and presents one example of typical data from a longwall coal mine PMID:26306052

  15. Reconnection of superfluid vortex bundles.

    PubMed

    Alamri, Sultan Z; Youd, Anthony J; Barenghi, Carlo F

    2008-11-21

    Using the vortex filament model and the Gross-Pitaevskii nonlinear Schroedinger equation, we show that bundles of quantized vortex lines in He II are structurally robust and can reconnect with each other maintaining their identity. We discuss vortex stretching in superfluid turbulence and show that, during the bundle reconnection process, kelvin waves of large amplitude are generated, in agreement with the finding that helicity is produced by nearly singular vortex interactions in classical Euler flows. PMID:19113421

  16. Bundle Formation in Biomimetic Hydrogels.

    PubMed

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J

    2016-08-01

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks. PMID:27409975

  17. Cohomology of line bundles: Applications

    NASA Astrophysics Data System (ADS)

    Blumenhagen, Ralph; Jurke, Benjamin; Rahn, Thorsten; Roschy, Helmut

    2012-01-01

    Massless modes of both heterotic and Type II string compactifications on compact manifolds are determined by vector bundle valued cohomology classes. Various applications of our recent algorithm for the computation of line bundle valued cohomology classes over toric varieties are presented. For the heterotic string, the prime examples are so-called monad constructions on Calabi-Yau manifolds. In the context of Type II orientifolds, one often needs to compute cohomology for line bundles on finite group action coset spaces, necessitating us to generalize our algorithm to this case. Moreover, we exemplify that the different terms in Batyrev's formula and its generalizations can be given a one-to-one cohomological interpretation. Furthermore, we derive a combinatorial closed form expression for two Hodge numbers of a codimension two Calabi-Yau fourfold.

  18. Chirality and equilibrium biopolymer bundles.

    PubMed

    Grason, Gregory M; Bruinsma, Robijn F

    2007-08-31

    We use continuum theory to show that chirality is a key thermodynamic control parameter for the aggregation of biopolymers: chirality produces a stable disperse phase of hexagonal bundles under moderately poor solvent conditions, as has been observed in in vitro studies of F actin [O. Pelletier et al., Phys. Rev. Lett. 91, 148102 (2003)]. The large characteristic radius of these chiral bundles is not determined by a mysterious long-range molecular interaction but by in-plane shear elastic stresses generated by the interplay between a chiral torque and an unusual, but universal, nonlinear gauge term in the strain tensor of ordered chains that is imposed by rotational invariance. PMID:17931038

  19. Exploring Bundling Theory with Geometry

    ERIC Educational Resources Information Center

    Eckalbar, John C.

    2006-01-01

    The author shows how instructors might successfully introduce students in principles and intermediate microeconomic theory classes to the topic of bundling (i.e., the selling of two or more goods as a package, rather than separately). It is surprising how much students can learn using only the tools of high school geometry. To be specific, one can…

  20. PDS4 Bundle Creation Governance Using BPMN

    NASA Astrophysics Data System (ADS)

    Radulescu, C.; Levoe, S. R.; Algermissen, S. S.; Rye, E. D.; Hardman, S. H.

    2015-06-01

    The AMMOS-PDS Pipeline Service (APPS) provides a Bundle Builder tool, which governs the process of creating, and ultimately generates, PDS4 bundles incrementally, as science products are being generated.

  1. Remote handling equipment and techniques used in the postirradiation examination of the severe fuel damage tests

    SciTech Connect

    Van Deusen, L.C.; Cook, B.A.

    1984-01-01

    Two, 32-rod, experimental fuel bundles from a pressurized water reactor have been subjected to severe reactor operation conditions in the Power Burst Facility. After testing, the fuel bundles were examined in a shielded, remotely handling facility to determine the condition of the bundles after a severe reactor transient. Special handling equipment and techniques were developed for unique application in the postirradiation examination of these large irradiated fuel bundles. This equipment was required to remotely handle the heavy, highly radioactive fuel bundles without disruption of the bundle geometry.

  2. NUCLEAR REACTOR FUEL ELEMENT

    DOEpatents

    Wheelock, C.W.; Baumeister, E.B.

    1961-09-01

    A reactor fuel element utilizing fissionable fuel materials in plate form is described. This fuel element consists of bundles of fuel-bearing plates. The bundles are stacked inside of a tube which forms the shell of the fuel element. The plates each have longitudinal fins running parallel to the direction of coolant flow, and interspersed among and parallel to the fins are ribs which position the plates relative to each other and to the fuel element shell. The plate bundles are held together by thin bands or wires. The ex tended surface increases the heat transfer capabilities of a fuel element by a factor of 3 or more over those of a simple flat plate.

  3. Anisotropic Turbulence Modeling for Accurate Rod Bundle Simulations

    SciTech Connect

    Baglietto, Emilio

    2006-07-01

    An improved anisotropic eddy viscosity model has been developed for accurate predictions of the thermal hydraulic performances of nuclear reactor fuel assemblies. The proposed model adopts a non-linear formulation of the stress-strain relationship in order to include the reproduction of the anisotropic phenomena, and in combination with an optimized low-Reynolds-number formulation based on Direct Numerical Simulation (DNS) to produce correct damping of the turbulent viscosity in the near wall region. This work underlines the importance of accurate anisotropic modeling to faithfully reproduce the scale of the turbulence driven secondary flows inside the bundle subchannels, by comparison with various isothermal and heated experimental cases. The very low scale secondary motion is responsible for the increased turbulence transport which produces a noticeable homogenization of the velocity distribution and consequently of the circumferential cladding temperature distribution, which is of main interest in bundle design. Various fully developed bare bundles test cases are shown for different geometrical and flow conditions, where the proposed model shows clearly improved predictions, in close agreement with experimental findings, for regular as well as distorted geometries. Finally the applicability of the model for practical bundle calculations is evaluated through its application in the high-Reynolds form on coarse grids, with excellent results. (author)

  4. Beta-peptide bundles with fluorous cores.

    PubMed

    Molski, Matthew A; Goodman, Jessica L; Craig, Cody J; Meng, He; Kumar, Krishna; Schepartz, Alanna

    2010-03-24

    We reported recently that certain beta-peptides self-assemble spontaneously into cooperatively folded bundles whose kinetic and thermodynamic metrics mirror those of natural helix bundle proteins. The structures of four such beta-peptide bundles are known in atomic detail. These structures reveal a solvent-sequestered, hydrophobic core stabilized by a unique arrangement of leucine side chains and backbone methylene groups. Here we report that this hydrophobic core can be re-engineered to contain a fluorous subdomain while maintaining the characteristic beta-peptide bundle fold. Like alpha-helical bundles possessing fluorous cores, fluorous beta-peptide bundles are stabilized relative to hydrocarbon analogues and undergo cold denaturation. Beta-peptide bundles with fluorous cores represent the essential first step in the synthesis of orthogonal protein assemblies that can sequester selectively in an interstitial membrane environment. PMID:20196598

  5. Quantum Bundles and Their Symmetries

    NASA Astrophysics Data System (ADS)

    Balachandran, A. P.; Marmo, G.; Simoni, A.; Sparano, G.

    Wave functions in the domain of observables such as the Hamiltonian are not always smooth functions on the classical configuration space Q. Rather, they are often best regarded as functions on a G bundle EG over Q or as sections of an associated bundle. If H is a classical group which acts on Q, its quantum version HG, which acts on EG, is not always H, but an extension of H by G. A powerful and physically transparent construction of EG and HG, where G=U(1) and H1(Q, Z)=0, has been developed using the path space {P}. ({P} consists of paths on Q from a fixed point.) In this paper we show how to construct EG and HG when G is U(1) or U(1)×π1(Q) and there is no restriction on H1(Q, Z). The method is illustrated with concrete examples, such as a system of charges and monopoles. We argue also that {P} is a sort of superbundle from which a large variety of bundles can be obtained by imposing suitable equivalence relations.

  6. Material distribution in light water reactor-type bundles tested under severe accident conditions

    SciTech Connect

    Noack, V.; Hagen, S.J.L.; Hofmann, P.; Schanz, G.; Sepold, L.K.

    1997-02-01

    Severe fuel damage experiments simulating small-break loss-of-coolant accidents have been carried out in the CORA out-of-pile test facility at Forschungszentrum Karlsruhe. Rod bundles with electrically heated fuel rod simulators containing annular UO{sub 2} pellets, UO{sub 2} full pellet rods, and absorber rods of two kinds (Ag/In/Cd to represent pressurized water reactor conditions and B{sub 4}C to represent boiling water reactor and VVER-1000 fuel elements) were subjected to temperature transients up to 2,300 K. A special method was applied to determine the axial mass distribution of bundle materials. The low-temperature melt formation by various interactions between zirconium and components of absorber and spacer grids strongly influences the bundle degradation and material relocation. Absorber materials can separate from the fuel by a noncoherent relocation of the materials at different temperatures. The distributions of solidified materials in the different test bundles show a clear dependence on the axial temperature profile. Coolant channel blockages are observed mainly at the lower end of the bundle, i.e., near the lowest elevation at which an oxidation excursion resulting from the highly exothermic zirconium-steam reaction had been experienced. This elevation corresponds with a steep axial temperature gradient in the maximum temperature attained. Oxide layers on Zircaloy result in reduced melt formation.

  7. Distribution of heating in an LVRF bundle due to dysprosium in the central element

    SciTech Connect

    Tsang, K.; Buijs, A.

    2006-07-01

    The computer code MCNP was used to establish the effect of adding dysprosium to the central pin of the proposed BRUCE-B CANFLEX{sup R} Low-Void-Reactivity Fuel (LVRF) on the heat load of the central pin and the heat balance inside the fuel bundle. The Dy generates heat through radiative capture of thermal neutrons, as well as through beta decay of {sup 165}Dy to {sup 165}Ho. We conclude that for fresh fuel, the presence of Dy contributes 26% of the overall heat to the central pin, and 0.5% to the whole fuel bundle. These percentages decrease to 11% and 0.5% at the end-of-life burnup condition. A second, operational quantity is the HPFP ratio (heating-power to fission-power ratio). This ratio is 1.63 for fresh fuel and decreases to 1.19 for fuel at the end-of-life burnup condition. (authors)

  8. Global analysis of bundle behavior in pressurized water reactor specific CORA experiments

    SciTech Connect

    Hering, W. ); Minato, Kazuo; Nagase, Fumihisa )

    1993-04-01

    At Kernforschungszentrum Karlsruhe, out-of-pile bundle experiments are performed in the CORA facility to investigate the behavior of light water reactor fuel elements during severe fuel damage accidents. To analyze the phenomena observed during the tests, such as claddin failure, oxidation, and deformation, as well as their influence on the post test bundle state, four pressurized water reactor specific tests are selected: CORA-2, CORA-3, CORA-5, and CORA-12. From each of these tests, a detailed global analysis using all the measured temperatures, pressures, and fluid compositions as well as videoscope information has been performed. To describe the post test bundle state quantitatively, axial profiles of the bundle cross-section area, the damage state of the rods, the average cladding oxidation, and the damage to the pellets are measured. The effects of CORA-specific components on the bundle melt progression and the measured axial profiles are identified and assessed. Most of the observations during the tests as well as the post test bundle state can be explained by the established common sequence of phenomena. For a better understanding of the melt progression, some physical phenomena, such as the energy release associated with the double-sided oxidation of the cladding, the melt release, or the melt relocation, must be analyzed in detail.

  9. Parallel transport on principal bundles over stacks

    NASA Astrophysics Data System (ADS)

    Collier, Brian; Lerman, Eugene; Wolbert, Seth

    2016-09-01

    In this paper we introduce a notion of parallel transport for principal bundles with connections over differentiable stacks. We show that principal bundles with connections over stacks can be recovered from their parallel transport thereby extending the results of Barrett, Caetano and Picken, and Schreiber and Waldorf from manifolds to stacks. In the process of proving our main result we simplify Schreiber and Waldorf's original definition of a transport functor for principal bundles with connections over manifolds and provide a more direct proof of the correspondence between principal bundles with connections and transport functors.

  10. Damping Properties of the Hair Bundle

    NASA Astrophysics Data System (ADS)

    Baumgart, Johannes; Kozlov, Andrei S.; Risler, Thomas; Hudspeth, A. J.

    2011-11-01

    The viscous liquid surrounding a hair bundle dissipates energy and dampens oscillations, which poses a fundamental physical challenge to the high sensitivity and sharp frequency selectivity of hearing. To identify the mechanical forces at play, we constructed a detailed finite-element model of the hair bundle. Based on data from the hair bundle of the bullfrog's sacculus, this model treats the interaction of stereocilia both with the surrounding liquid and with the liquid in the narrow gaps between the individual stereocilia. The investigation revealed that grouping stereocilia in a bundle dramatically reduces the total drag. During hair-bundle deflections, the tip links potentially induce drag by causing small but very dissipative relative motions between stereocilia; this effect is offset by the horizontal top connectors that restrain such relative movements at low frequencies. For higher frequencies the coupling liquid is sufficient to assure that the hair bundle moves as a unit with a low total drag. This work reveals the mechanical characteristics originating from hair-bundle morphology and shows quantitatively how a hair bundle is adapted for sensitive mechanotransduction.

  11. Fock modules and noncommutative line bundles

    NASA Astrophysics Data System (ADS)

    Landi, Giovanni

    2016-09-01

    To a line bundle over a noncommutative space there is naturally associated a Fock module. The algebra of corresponding creation and annihilation operators is the total space algebra of a principal U(1) -bundle over the noncommutative space. We describe the general construction and illustrate it with examples.

  12. Net order optimization in analog net bundles

    NASA Astrophysics Data System (ADS)

    Jambor, Thomas; Schreiner, Lars; Olbrich, Markus; Barke, Erich

    2005-06-01

    This paper presents a new approach to optimize net order in analog busses. It is used for the PARasitic SYmmetric router (PARSY), which routes net bundles, e.g. busses or differential pairs, maintaining parasitic symmetry and limiting differential coupling. The router is mainly devoted to analog signal interconnect but can also be used for critical digital busses. Net bundles have a fixed order, because wire crossing is not allowed in net bundle segments to enforce symmetry. Wires inside net bundle segments are generated by module generators. Connecting cell terminals to the first or the last net bundle segment is complex, because the cell terminals can vary in geometry and placement. Therefore, an assignment between nets and wires (net order) in a segment is required. This assignment does not affect the order in which nets or net bundles are routed sequentially. The optimization objective for the connections from net bundle segments to terminals is to minimize the number of crossings and the length difference, while maintaining symmetry if possible. Therefore, a net order has to be calculated, which globally optimizes these criteria for all terminal connections. Different net orders can be computed from the placement of terminals, which have to be connected to a net bundle segment. An additional order is calculated from these net orders, which contains the most characteristic features of all net orders. For all net orders costs are evaluated, and the one with the lowest cost is chosen.

  13. Delay Tolerant Networking - Bundle Protocol Simulation

    NASA Technical Reports Server (NTRS)

    SeGui, John; Jenning, Esther

    2006-01-01

    In this paper, we report on the addition of MACHETE models needed to support DTN, namely: the Bundle Protocol (BP) model. To illustrate the useof MACHETE with the additional DTN model, we provide an example simulation to benchmark its performance. We demonstrate the use of the DTN protocol and discuss statistics gathered concerning the total time needed to simulate numerous bundle transmissions.

  14. Line bundle embeddings for heterotic theories

    NASA Astrophysics Data System (ADS)

    Nibbelin, Stefan Groot; Ruehle, Fabian

    2016-04-01

    In heterotic string theories consistency requires the introduction of a non-trivial vector bundle. This bundle breaks the original ten-dimensional gauge groups E8 × E8 or SO(32) for the supersymmetric heterotic string theories and SO(16) × SO(16) for the non-supersymmetric tachyon-free theory to smaller subgroups. A vast number of MSSM-like models have been constructed up to now, most of which describe the vector bundle as a sum of line bundles. However, there are several different ways of describing these line bundles and their embedding in the ten-dimensional gauge group. We recall and extend these different descriptions and explain how they can be translated into each other.

  15. Preliminary report: NIF laser bundle review

    SciTech Connect

    Tietbohl, G.L.; Larson, D.W.; Erlandson, A.C.

    1995-08-31

    As requested in the guidance memo {sup 1}, this committe determined whether there are compelling reasons to recommend a change from the NIF CDR baseline laser. The baseline bundle design based on a tradeoff between cost and technical risk, which is replicated four times to create the required 192 beams. The baseline amplifier design uses bottom loading 1{times}4 slab and flashlamp cassettes for amplifier maintenance and large vacuum enclosures (2.5m high {times} 7m wide in cross-section for each of the two spatial filters in each of the four bundles. The laser beams are arranged in two laser bays configured in a u-shape around the target area. The entire bundle review effort was performed in a very short time (six weeks) and with limited resources (15 personnel part-time). This should be compared to the effort that produced the CDR design (12 months, 50 to 100 personnel). This committee considered three alternate bundle configurations (2{times}2, 4{times}2, and 4{times}4 bundles), and evaluated each bundle against the baseline design using the seven requested issues in the guidance memo: Cost; schedule; performance risk; maintainability/operability; hardware failure cost exposure; activation; and design flexibility. The issues were reviewed to identify differences between each alternate bundle configuration and the baseline.

  16. Prioritary omalous bundles on Hirzebruch surfaces

    NASA Astrophysics Data System (ADS)

    Aprodu, Marian; Marchitan, Marius

    2016-01-01

    An irreducible algebraic stack is called unirational if there exists a surjective morphism, representable by algebraic spaces, from a rational variety to an open substack. We prove unirationality of the stack of prioritary omalous bundles on Hirzebruch surfaces, which implies also the unirationality of the moduli space of omalous H-stable bundles for any ample line bundle H on a Hirzebruch surface (compare with Costa and Miro-Ŕoig, 2002). To this end, we find an explicit description of the duals of omalous rank-two bundles with a vanishing condition in terms of monads. Since these bundles are prioritary, we conclude that the stack of prioritary omalous bundles on a Hirzebruch surface different from P1 ×P1 is dominated by an irreducible section of a Segre variety, and this linear section is rational (Ionescu, 2015). In the case of the space quadric, the stack has been explicitly described by N. Buchdahl. As a main tool we use Buchdahl's Beilinson-type spectral sequence. Monad descriptions of omalous bundles on hypersurfaces in P4, Calabi-Yau complete intersection, blowups of the projective plane and Segre varieties have been recently obtained by A.A. Henni and M. Jardim (Henni and Jardim, 2013), and monads on Hirzebruch surfaces have been applied in a different context in Bartocci et al. (2015).

  17. Calculation of Quad-Cities Central Bundle Documented by the U.S. in FY98 Using Russian Computer Codes

    SciTech Connect

    Pavlovichev, A.M.

    2001-06-19

    The report presents calculation results of isotopic composition of irradiated fuel performed for the Quad Cities-1 reactor bundle with UO{sub 2} and MOX fuel. The MCU-REA code was used for calculations. The code is developed in Kurchatov Institute, Russia. The MCU-REA results are compared with the experimental data and HELIOS code results.

  18. Contraction of cross-linked actomyosin bundles

    NASA Astrophysics Data System (ADS)

    Yoshinaga, Natsuhiko; Marcq, Philippe

    2012-08-01

    Cross-linked actomyosin bundles retract when severed in vivo by laser ablation, or when isolated from the cell and micromanipulated in vitro in the presence of ATP. We identify the timescale for contraction as a viscoelastic time τ, where the viscosity is due to (internal) protein friction. We obtain an estimate of the order of magnitude of the contraction time τ ≈ 10-100 s, consistent with available experimental data for circumferential microfilament bundles and stress fibers. Our results are supported by an exactly solvable, hydrodynamic model of a retracting bundle as a cylinder of isotropic, active matter, from which the order of magnitude of the active stress is estimated.

  19. Actively Contracting Bundles of Polar Filaments

    NASA Astrophysics Data System (ADS)

    Kruse, K.; Jülicher, F.

    2000-08-01

    We introduce a phenomenological model to study the properties of bundles of polar filaments which interact via active elements. The stability of the homogeneous state, the attractors of the dynamics in the unstable regime, and the tensile stress generated in the bundle are discussed. We find that the interaction of parallel filaments can induce unstable behavior and is responsible for active contraction and tension in the bundle. The interaction between antiparallel filaments leads to filament sorting. Our model could apply to simple contractile structures in cells such as stress fibers.

  20. Requirements for contractility in disordered cytoskeletal bundles

    NASA Astrophysics Data System (ADS)

    Lenz, Martin; Gardel, Margaret L.; Dinner, Aaron R.

    2012-03-01

    Actomyosin contractility is essential for biological force generation, and is well understood in highly organized structures such as striated muscle. Additionally, actomyosin bundles devoid of this organization are known to contract both in vivo and in vitro, which cannot be described by standard muscle models. To narrow down the search for possible contraction mechanisms in these systems, we investigate their microscopic symmetries. We show that contractile behavior requires non-identical motors that generate large-enough forces to probe the nonlinear elastic behavior of F-actin. This suggests a role for filament buckling in the contraction of these bundles, consistent with recent experimental results on reconstituted actomyosin bundles.

  1. Characteristic classes associated to Q-bundles

    NASA Astrophysics Data System (ADS)

    Kotov, Alexei; Strobl, Thomas

    2015-10-01

    A Q-manifold is a graded manifold endowed with a vector field of degree 1 squaring to zero. We consider the notion of a Q-bundle, that is, a fiber bundle in the category of Q-manifolds. To each homotopy class of "gauge fields" (sections in the category of graded manifolds) and each cohomology class of a certain subcomplex of forms on the fiber we associate a cohomology class on the base. As any principal bundle yields canonically a Q-bundle, this construction generalizes Chern-Weil classes. Novel examples include cohomology classes that are locally de Rham differential of the integrands of topological sigma models obtained by the AKSZ-formalism in arbitrary dimensions. For Hamiltonian Poisson fibrations one obtains a characteristic 3-class in this manner. We also relate the framework to equivariant cohomology and Lecomte's characteristic classes of exact sequences of Lie algebras.

  2. Quantum Bundle Description of Quantum Projective Spaces

    NASA Astrophysics Data System (ADS)

    Ó Buachalla, Réamonn

    2012-12-01

    We realise Heckenberger and Kolb's canonical calculus on quantum projective ( N - 1)-space C q [ C p N-1] as the restriction of a distinguished quotient of the standard bicovariant calculus for the quantum special unitary group C q [ SU N ]. We introduce a calculus on the quantum sphere C q [ S 2 N-1] in the same way. With respect to these choices of calculi, we present C q [ C p N-1] as the base space of two different quantum principal bundles, one with total space C q [ SU N ], and the other with total space C q [ S 2 N-1]. We go on to give C q [ C p N-1] the structure of a quantum framed manifold. More specifically, we describe the module of one-forms of Heckenberger and Kolb's calculus as an associated vector bundle to the principal bundle with total space C q [ SU N ]. Finally, we construct strong connections for both bundles.

  3. Robust incoherent fiber optic bundle decoder

    NASA Technical Reports Server (NTRS)

    Roberts, Hilary E. (Inventor); DePlachett, Charles P. (Inventor); Deason, Brent E. (Inventor); Pilgrim, Robert A. (Inventor); Sanford, Harold S. (Inventor)

    2003-01-01

    Apparatus and method for calibrating an incoherent fiber optic bundle for use in transmitting visual or infrared coherent images. The apparatus includes a computer, a computer video monitor, an objective lens adjacent to the input end of the bundle, a second lens adjacent the output end of the bundle, and a CCD camera. The camera transmits video data to the monitor to produce an illuminated fiber optic image. The coordinates for the center of each fiber is found through an imaging process and the output fibers coordinates are related to the input fiber coordinates and processed in the computer to produce a mapping lookup-table (LUT) unique to the specific fiber bundle. Remapping of the LUT due to changes in the lens focus, CCD camera, or the addition of an infrared filter is accomplished by a software utility in the computer.

  4. Sealed fiber-optic bundle feedthrough

    DOEpatents

    Tanner, Carol E.

    2002-01-01

    A sealed fiber-optic bundle feedthrough by which a multitude of fiber-optic elements may be passed through an opening or port in a wall or structure separating two environments at different pressures or temperatures while maintaining the desired pressure or temperature in each environment. The feedthrough comprises a rigid sleeve of suitable material, a bundle of individual optical fibers, and a resin-based sealing material that bonds the individual optical fibers to each other and to the rigid sleeve.

  5. Simulating Topological Defects in Twisted Fiber Bundles

    NASA Astrophysics Data System (ADS)

    Bruss, Isaac R.; Grason, Gregory M.

    2012-02-01

    Twisted bundles are a common motif found in naturally occurring structures of self-assembled fibers, such as collagen and fibrin. By understanding the general principles governing such organizations, new synthetic materials--from the nano to the macroscale--may also be realized. Recently, continuum elasticity theory has been applied to describe generic twisted fiber bundles. This has revealed a relation between a bundle's twist and the presence of topological defects in the cross-sectional packing of the fibers. Here we employ numerical simulations to examine this interdependence. We model a bundle's cross-section as beads confined to a plane. The interactions between beads is governed by a modified Lennard-Jones potential that accounts for the effects of twist. We observe configurations that range from perfect hexagonal packing for cases of no twist, to defect populated structures above a critical amount of twist. For small bundles of less than ˜100 beads, there exists a discrete spectrum of energy ground states corresponding to integer numbers of five-fold disclinations. For larger bundles, we hope to uncover what types of defect arrangements effectively screen the stresses caused by twist, and compare these to current predictions of the internal organization of collagen fibrils.

  6. Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Final report

    SciTech Connect

    Todreas, N.E.; Cheng, S.K.; Basehore, K.

    1984-08-01

    This project principally undertook the investigation of the thermal hydraulic performance of wire wrapped fuel bundles of LMFBR configuration. Results obtained included phenomenological models for friction factors, flow split and mixing characteristics; correlations for predicting these characteristics suitable for insertion in design codes; numerical codes for analyzing bundle behavior both of the lumped subchannel and distributed parameter categories and experimental techniques for pressure velocity, flow split, salt conductivity and temperature measurement in water cooled mockups of bundles and subchannels. Flow regimes investigated included laminar, transition and turbulent flow under forced convection and mixed convection conditions. Forced convections conditions were emphasized. Continuing efforts are underway at MIT to complete the investigation of the mixed convection regime initiated here. A number of investigations on outlet plenum behavior were also made. The reports of these investigations are identified.

  7. Buckling Behavior of Individual and Bundled Microtubules

    PubMed Central

    Soheilypour, Mohammad; Peyro, Mohaddeseh; Peter, Stephen J.; Mofrad, Mohammad R.K.

    2015-01-01

    As the major structural constituent of the cytoskeleton, microtubules (MTs) serve a variety of biological functions that range from facilitating organelle transport to maintaining the mechanical integrity of the cell. Neuronal MTs exhibit a distinct configuration, hexagonally packed bundles of MT filaments, interconnected by MT-associated protein (MAP) tau. Building on our previous work on mechanical response of axonal MT bundles under uniaxial tension, this study is focused on exploring the compression scenarios. Intracellular MTs carry a large fraction of the compressive loads sensed by the cell and therefore, like any other column-like structure, are prone to substantial bending and buckling. Various biological activities, e.g., actomyosin contractility and many pathological conditions are driven or followed by bending, looping, and buckling of MT filaments. The coarse-grained model previously developed in our lab has been used to study the mechanical behavior of individual and bundled in vivo MT filaments under uniaxial compression. Both configurations show tip-localized, decaying, and short-wavelength buckling. This behavior highlights the role of the surrounding cytoplasm and MAP tau on MT buckling behavior, which allows MT filaments to bear much larger compressive forces. It is observed that MAP tau interconnections improve this effect by a factor of two. The enhanced ability of MT bundles to damp buckling waves relative to individual MT filaments, may be interpreted as a self-defense mechanism because it helps axonal MTs to endure harsher environments while maintaining their function. The results indicate that MT filaments in a bundle do not buckle simultaneously implying that the applied stress is not equally shared among the MT filaments, that is a consequence of the nonuniform distribution of MAP tau proteins along the bundle length. Furthermore, from a pathological perspective, it is observed that axonal MT bundles are more vulnerable to failure in

  8. Nerve Bundles and Deep Dyspareunia in Endometriosis.

    PubMed

    Williams, Christina; Hoang, Lien; Yosef, Ali; Alotaibi, Fahad; Allaire, Catherine; Brotto, Lori; Fraser, Ian S; Bedaiwy, Mohamed A; Ng, Tony L; Lee, Anna F; Yong, Paul J

    2016-07-01

    The etiology of deep dyspareunia in endometriosis is unclear. Our objective was to determine whether nerve bundle density in the cul-de-sac/uterosacrals (zone II) is associated with deep dyspareunia in women with endometriosis. We conducted a blinded retrospective immunohistochemistry study (n = 58) at a tertiary referral center (2011-2013). Patients were stringently phenotyped into a study group and 2 control groups. The study group (tender endometriosis, n = 29) consisted of patients with deep dyspareunia, a tender zone II on examination, and an endometriosis lesion in zone II excised at surgery. Control group 1 (nontender endometriosis, n = 17) consisted of patients without deep dyspareunia, a nontender zone II on examination, and an endometriosis lesion in zone II excised at surgery. Control group 2 (tender nonendometriosis, n = 12) consisted of patients with deep dyspareunia, a tender zone II on examination, and a nonendometriosis lesion (eg, normal histology) in zone II excised at surgery. Protein gene product 9.5 (PGP9.5) immunohistochemistry was performed to identify nerve bundles (nerve fibers surrounded by perineurium) in the excised zone II lesion. PGP9.5 nerve bundle density (bundles/high powered field [HPF]) was then scored by a pathologist blinded to the group. We found a significant difference in PGP9.5 nerve bundle density between the 3 groups (analysis of variance, F2,55 = 6.39, P = .003). Mean PGP9.5 nerve bundle density was significantly higher in the study group (1.16 ± 0.56 bundles/HPF [±standard deviation]) compared to control group 1 (0.65 ± 0.36, Tukey test, P = .005) and control group 2 (0.72 ± 0.56, Tukey test, P = .044). This study provides evidence that neurogenesis in the cul-de-sac/uterosacrals may be an etiological factor for deep dyspareunia in endometriosis. PMID:26711313

  9. Mechanism of Actin Filament Bundling by Fascin

    SciTech Connect

    Jansen, Silvia; Collins, Agnieszka; Yang, Changsong; Rebowski, Grzegorz; Svitkina, Tatyana; Dominguez, Roberto

    2013-03-07

    Fascin is the main actin filament bundling protein in filopodia. Because of the important role filopodia play in cell migration, fascin is emerging as a major target for cancer drug discovery. However, an understanding of the mechanism of bundle formation by fascin is critically lacking. Fascin consists of four {beta}-trefoil domains. Here, we show that fascin contains two major actin-binding sites, coinciding with regions of high sequence conservation in {beta}-trefoil domains 1 and 3. The site in {beta}-trefoil-1 is located near the binding site of the fascin inhibitor macroketone and comprises residue Ser-39, whose phosphorylation by protein kinase C down-regulates actin bundling and formation of filopodia. The site in {beta}-trefoil-3 is related by pseudo-2-fold symmetry to that in {beta}-trefoil-1. The two sites are {approx}5 nm apart, resulting in a distance between actin filaments in the bundle of {approx}8.1 nm. Residue mutations in both sites disrupt bundle formation in vitro as assessed by co-sedimentation with actin and electron microscopy and severely impair formation of filopodia in cells as determined by rescue experiments in fascin-depleted cells. Mutations of other areas of the fascin surface also affect actin bundling and formation of filopodia albeit to a lesser extent, suggesting that, in addition to the two major actin-binding sites, fascin makes secondary contacts with other filaments in the bundle. In a high resolution crystal structure of fascin, molecules of glycerol and polyethylene glycol are bound in pockets located within the two major actin-binding sites. These molecules could guide the rational design of new anticancer fascin inhibitors.

  10. Photothermal imaging through coherent infrared bundles

    NASA Astrophysics Data System (ADS)

    Milstein, Yonat; Tepper, Michal; Harrington, James A.; Ben David, Moshe; Gannot, Israel

    2011-03-01

    This study aims to develop a photothermal imaging system through a coherent infrared bundle. This system will be used to determine the oxygenation level of various tissues, suspected malignant tissues in particular. The oxygenation estimation is preformed using a computerized algorithm. In order to evaluate the system, different bundle configurations were used for the determination of the optimal one. Bundle transmittance and the algorithm's estimation ability were measured, measurements were performed using agar phantoms consisting of varying ratios of Methylene Blue and ICG. A bundle consisting of 19 Teflon waveguides with a of 1.1mm was found to be the optimal configuration with an RMS of the error of 9.38%. At a second stage the system was validated on blood samples with varying oxygenation levels and there oxygenation levels were estimated. This stage had an RMS of the error of 10.16% for the oxygenation level estimation for samples with a 50% oxygenation level and higher. Once the basic system was validated successfully on agar phantoms and blood samples a portable system was designed and built in order to fit the system for portable use. The portable system consists of a white light illuminating source followed by filters transmitting certain wavelengths, a transmitting fiber, a thermal imaging bundle and a portable thermal camera. This portable system will be evaluated in order to have an adequate portable system for implementing the method out of the lab.

  11. Double bundle or single bundle plus extraarticular tenodesis in ACL reconstruction? A CAOS study.

    PubMed

    Monaco, E; Labianca, L; Conteduca, F; De Carli, A; Ferretti, A

    2007-10-01

    Anatomic reconstructions of anterior cruciate ligament (ACL) with double bundle gracilis and semitendonosus tendons graft, reproducing AM and PL bundles, have been introduced to offer a better biomechanical outcome, especially during rotatory loads. On the other hand, many methods of tenodesing the lateral aspect of the tibia to the femur to reduce internal rotation (IR) of the tibia and minimize anterior translation of the tibia relative to the femur as a backup for intra-articular reconstruction, have been also suggested. The goal of this study is to evaluate the effect, on the IR of the tibia, of a lateral reconstruction in addition to a standard single bundle ACL reconstruction as compared with an anatomic double bundle ACL reconstruction. Computer assisted ACL reconstruction has been used because it could be very effective in evaluating the global kinematic performance of the reconstructed knee. We selected 20 consecutive ACL reconstruction procedures to be performed in males in our hospital. Patients were alternately assigned to one of the two groups--group A: standard single bundle ACL reconstruction with doubled gracilis and semitendinosus tendons graft with an arthroscopically assisted two incisions technique and a lateral extraarticular reconstruction; group B: double bundle ACL reconstruction with doubled gracilis and semitendinosus tendons graft with an arthroscopically assisted two incisions technique. In all ACL reconstruction procedures navigation process was performed. Both surgical techniques reduced significantly AP displacement, IR and external rotation (ER) of the tibia respect to pre-operative ACL deficient condition (p<0.05). Comparing the group A after the single bundle reconstruction and the group B after the AM bundle fixation, non differences were found in AP displacement, IR and ER of the tibia (p=0.75, p=0.07 and p=0.07 respectively; power: 0.94). Comparing the group A after the addition of the lateral tenodesis and group B after the PL

  12. A Kinetic Model of Active Extensile Bundles

    NASA Astrophysics Data System (ADS)

    Goldstein, Daniel; Chakraborty, Bulbul; Baskaran, Aparna

    Recent experiments in active filament networks reveal interesting rheological properties (Dan Chen: APS March Meeting 2015 D49.00001). This system consumes ATP to produce an extensile motion in bundles of microtubules. This extension then leads to self generated stresses and spontaneous flows. We propose a minimal model where the activity is modeled by self-extending bundles that are part of a cross linked network. This network can reorganize itself through buckling of extending filaments and merging events that alter the topology of the network. We numerically simulate this minimal kinetic model and examine the emergent rheological properties and determine how stresses are generated by the extensile activity. We will present results that focus on the effects of confinement and network connectivity of the bundles on stress fluctuations and response of an active gel.

  13. Extremal Bundles on Calabi-Yau Threefolds

    NASA Astrophysics Data System (ADS)

    Gao, Peng; He, Yang-Hui; Yau, Shing-Tung

    2015-06-01

    We study constructions of stable holomorphic vector bundles on Calabi-Yau threefolds, especially those with exact anomaly cancellation which we call extremal. By going through the known databases we find that such examples are rare in general and can be ruled out for the spectral cover construction for all elliptic threefolds. We then introduce a general Hartshorne-Serre construction and use it to find extremal bundles of general ranks and study their stability, as well as computing their Chern numbers. Based on both existing and our new constructions, we revisit the DRY conjecture for the existence of stable sheaves on Calabi-threefolds, and provide theoretical and numerical evidence for its correctness. Our construction can be easily generalized to bundles with no extremal conditions imposed.

  14. Hydrodynamic interaction of bacterial flagella - flagellar bundling

    NASA Astrophysics Data System (ADS)

    Lim, Sookkyung

    2013-11-01

    Flagellar bundling is an important aspect of locomotion in bacteria such as Escherichia coli. To study the hydrodynamic behavior of helical flagella, we present a computational model that is based on the geometry of the bacterial flagellar filament at the micrometer scale. We consider two model flagella, each of which has a rotary motor at its base with the rotation rate of the motor set at 100 Hz. Bundling occurs when both flagella are left-handed helices turning counterclockwise (when viewed from the nonmotor end of the flagellum looking back toward the motor) or when both flagella are right-handed helices turning clockwise. Helical flagella of the other combinations of handedness and rotation direction do not bundle. In this work we use the generalized immersed boundary method combined with the unconstrained Kirchhoff rod theory, which allows us to study the complicated hydrodynamics of flagellar behavior. This is a joint work with Charlie Peskin at NYU. NSF

  15. Carbon nanotube bundles under electric field perturbations

    NASA Astrophysics Data System (ADS)

    Hammes, I.; Latgé, A.

    2012-03-01

    Here we address the important role played by electric fields applied in carbon nanotube bundles in providing convenient scenarios for their use in electronic devices. We show that a gap modulation may be derived depending on the bundle configuration and the details of the applied field configuration. The system is described by a tight binding Hamiltonian and the Green function formalism is used to calculate the local density of states. Small bundles were used to validate our model on the basis of ab initio calculations. Further analysis shows that the number of tubes, geometrical configuration details and field intensities may be controlled to tune the electronic structure close to the Fermi energy, envisaging atomic-scale devices.

  16. Porous Silicon and Denim Fiber Bundle Characterization

    NASA Astrophysics Data System (ADS)

    Deuro, Randi Ellen

    My thesis research aims to characterize and exploit materials in an efficient, rapid, non-destructive manner. Part I of this document summarizes my research on porous silicon (pSi) design, fabrication, and surface modification for use as a novel chemical sensor. The optimization of fabrication process parameters (etching time, etching solution, electrode shape, and the fixing process) on pSi photoluminescence (PL) is presented. I have also investigated the effects of analyte vapors (acetonitrile, toluene, methanol, acetone) on the pSi PL and surface chemistry using luminescence and Fourier-transform infrared (FT-IR) spectroscopy and microscopy methods. The mechanism and benefits of one method of pSi surface modification and protection (ultraviolet (UV) hydrosilylation) will also be presented. Finally, high thorough-put methods of pSi sensor production are described. In Part II of this document, I introduce a novel technique for analyzing and discriminating among denim fiber bundles. An investigation into the benefits of luminescence-based multispectral imaging (LMSI) for denim fiber bundle identification has been conducted. I explore the power of nitromethane (CH 3NO2) based quenching in fiber bundle classification and identify the quenching mechanism. The luminescence spectra (450 - 850 nm) and images from the denim fiber bundles were obtained while exciting at 325 nm or 405 nm. Here, LMSI data were recorded in < 10 s and subsequently assessed by principal component analysis (PCA) and rendered red, green, blue (RGB) component histograms. The results show that LMSI data can be used to rapidly and uniquely classify all the fiber bundle types studied in this research. These non-destructive techniques eliminate extensive sample preparation and allow for rapid multispectral image collection, analysis, and assessment. The quenching data also revealed that the dye molecules within the individual fiber bundles exhibited dramatically different accessibilities to CH 3NO2.

  17. Infrared imaging with fiber optic bundles

    NASA Astrophysics Data System (ADS)

    Hilton, Albert R., Sr.; McCord, James; Thompson, W. S.; LeBlanc, Richard A.

    2003-09-01

    Efforts have resumed to improve the image quality of infrared imaging bundles formed at AMI using the ribbon stacking method. The C4 glass has been used to reduce core size, increase packing density and improve flexibility. Ribbons are formed from unclad fiber wound on a drum with pitch, ribbon count and spacing between ribbons computer controlled. A small portion of each ribbon is compressed and fused using thin, dilute Epoxy. Unfortunately, the Epoxy, serving as a clad, absorbs most all the LWIR energy making the bundles unsuited for 8-12 μm cameras. The ribbons are removed from the drum and stacked, one on top of the other observing proper orientation to form the bundle. A typical 1 meter bundle is formed from 50-70 count ribbons for a total of 2500-4900 fibers, made from 2.5-4.9 Km of C4 fiber. Typical core diameters are 60-80 μm. Active surface area ranges from 60-70%. Infrared resolution images formed using a NIR tube camera equipped with a special relay lens demonstrates the resolution limit for the bundle. Currently, the limit is about 10 lp/mm. The bundle end is imaged in the 3-5 μm Agema 210 camera using an Amtir 1 F/1 meniscus, coated 3-5 μm. Video images taken in natural light of an individual, easily recognizable at 50 feet, will be shown. Results of careful evaluation carried out at Lockheed Martin in Orlando using a high performance Raytheon Galileo camera will be presented.

  18. Bundling in semiflexible polymers: A theoretical overview.

    PubMed

    Benetatos, Panayotis; Jho, YongSeok

    2016-06-01

    Supramolecular assemblies of polymers are key modules to sustain the structure of cells and their function. The main elements of these assemblies are charged semiflexible polymers (polyelectrolytes) generally interacting via a long(er)-range repulsion and a short(er)-range attraction. The most common supramolecular structure formed by these polymers is the bundle. In the present paper, we critically review some recent theoretical and computational advances on the problem of bundle formation, and point a few promising directions for future work. PMID:26813628

  19. Scaling Shift in Multicracked Fiber Bundles

    NASA Astrophysics Data System (ADS)

    Manca, Fabio; Giordano, Stefano; Palla, Pier Luca; Cleri, Fabrizio

    2014-12-01

    Bundles of fibers, wires, or filaments are ubiquitous structures in both natural and artificial materials. We investigate the bundle degradation induced by an external damaging action through a theoretical model describing an assembly of parallel fibers, progressively damaged by a random population of cracks. Fibers in our model interact by means of a lateral linear coupling, thus retaining structural integrity even after substantial damage. Monte Carlo simulations of the Young's modulus degradation for increasing crack density demonstrate a remarkable scaling shift between an exponential and a power-law regime. Analytical solutions of the model confirm this behavior, and provide a thorough understanding of the underlying physics.

  20. Crosstalk analysis of carbon nanotube bundle interconnects.

    PubMed

    Zhang, Kailiang; Tian, Bo; Zhu, Xiaosong; Wang, Fang; Wei, Jun

    2012-01-01

    Carbon nanotube (CNT) has been considered as an ideal interconnect material for replacing copper for future nanoscale IC technology due to its outstanding current carrying capability, thermal conductivity, and mechanical robustness. In this paper, crosstalk problems for single-walled carbon nanotube (SWCNT) bundle interconnects are investigated; the interconnect parameters for SWCNT bundle are calculated first, and then the equivalent circuit has been developed to perform the crosstalk analysis. Based on the simulation results using SPICE simulator, the voltage of the crosstalk-induced glitch can be reduced by decreasing the line length, increasing the spacing between adjacent lines, or increasing the diameter of SWCNT. PMID:22340628

  1. Scaling shift in multicracked fiber bundles.

    PubMed

    Manca, Fabio; Giordano, Stefano; Palla, Pier Luca; Cleri, Fabrizio

    2014-12-19

    Bundles of fibers, wires, or filaments are ubiquitous structures in both natural and artificial materials. We investigate the bundle degradation induced by an external damaging action through a theoretical model describing an assembly of parallel fibers, progressively damaged by a random population of cracks. Fibers in our model interact by means of a lateral linear coupling, thus retaining structural integrity even after substantial damage. Monte Carlo simulations of the Young's modulus degradation for increasing crack density demonstrate a remarkable scaling shift between an exponential and a power-law regime. Analytical solutions of the model confirm this behavior, and provide a thorough understanding of the underlying physics. PMID:25554893

  2. Balance Ability and Proprioception after Single-Bundle, Single-Bundle Augmentation, and Double-Bundle ACL Reconstruction

    PubMed Central

    Ma, Yubao; Iwaki, Daisuke; Asaeda, Makoto; Adachi, Nobuo; Ochi, Mitsuo

    2014-01-01

    Purpose. The present study sought to determine the influences of single-bundle (SB), single-bundle augmentation (SBA), and double-bundle (DB) reconstructions on balance ability and proprioceptive function. Methods. 67 patients who underwent a single- or double-bundle ACL reconstruction or a SBA using multistranded autologous hamstring tendons were included in this study with a 1-year follow-up. Body sway and knee kinesthesia (using the threshold to detect passive motion test (TTDPM)) were measured to indicate balance ability and proprioceptive function, respectively. Additionally, within-subject differences in anterior-posterior stability of the tibia and lower extremity muscle strength were evaluated before and after surgery. Results. At 6 and 12 months after surgery, DB reconstruction resulted in better balance and proprioceptive function than SB reconstruction (P < 0.05). Although no significant difference was observed in balance ability or proprioceptive function between the SBA and DB reconstructions, knee stability was significantly better with SBA and DB reconstructions than SB reconstruction (P < 0.05). No significant differences were found in quadriceps and hamstrings strength among the three reconstruction techniques. Conclusions. Our findings consider that joint stability, proprioceptive function, and balance ability were superior with SBA and DB reconstructions compared to SB reconstruction at 6 and 12 months after surgery. PMID:25614884

  3. Social Bundles: Thinking through the Infant Body

    ERIC Educational Resources Information Center

    Brownlie, Julie; Leith, Valerie M. Sheach

    2011-01-01

    Drawing on a UK research study on immunization, this article investigates parents' understandings of the relationship between themselves, their infants, other bodies, the state, and cultural practices--material and symbolic. The article argues that infant bodies are best thought of as always social bundles, rather than as biobundles made social…

  4. High precision optical fiber bundle displacement sensor

    NASA Astrophysics Data System (ADS)

    Cao, Hui-min; Chen, You-ping; Zhang, Gang; Zhou, Zu-de

    2006-02-01

    A noncontact optical fiber bundle displacement sensor with nanometer resolution and low drift is proposed. The principle of the sensor is based on reflective intensity modulation technique. The optical fiber bundle probe contains one transmitting bundle and two receiving bundles. There are 727 identical glass optical fibers with a diameter of 50μm arranged in a concentric random pattern at the probe end. The diameter of the probe coated with a thin stainless ferrule is as small as 2.5mm. A carrier amplifier system is adopted to reduce dc drift and the interference of ambient stray light. The disturbance caused by fluctuation of light source and variation of target surface reflectivity is eliminated by taking a ratio of two receiving signals. The thermal drifts from two photoelectric signal processing circuits cancel out each other by using elements with identical specifications for both photodetector-amplifier chains. The sensitivity of the sensor is 5.9mV/nm over a linear range of 700-2300μm with a nonlinearity of 1%. The achieved resolution is 1nm/square root Hz; over a dynamic bandwidth of 10KHz and the dynamic range is 286dB. It has been proved that the sensor run sufficiently well when used with nano-technological instruments.

  5. The Bundled Payments for Care Improvement Initiative.

    PubMed

    Hirsch, Joshua A; Leslie-Mazwi, Thabele M; Barr, Robert M; McGinty, Geraldine; Nicola, Gregory N; Silva, Ezequiel; Manchikanti, Laxmaiah

    2016-05-01

    The Affordable Care Act enters its fifth year firmly entrenched in our national consciousness. One method that has entered the vernacular for achieving cost savings is accountable care. There are other approaches that are less well known. The Bundled Payments for Care Improvement Initiative has the potential to significantly impact neurointerventionalists. We review that initiative here. PMID:25829366

  6. Interplanetary Overlay Network Bundle Protocol Implementation

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.

    2011-01-01

    The Interplanetary Overlay Network (ION) system's BP package, an implementation of the Delay-Tolerant Networking (DTN) Bundle Protocol (BP) and supporting services, has been specifically designed to be suitable for use on deep-space robotic vehicles. Although the ION BP implementation is unique in its use of zero-copy objects for high performance, and in its use of resource-sensitive rate control, it is fully interoperable with other implementations of the BP specification (Internet RFC 5050). The ION BP implementation is built using the same software infrastructure that underlies the implementation of the CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol (CFDP) built into the flight software of Deep Impact. It is designed to minimize resource consumption, while maximizing operational robustness. For example, no dynamic allocation of system memory is required. Like all the other ION packages, ION's BP implementation is designed to port readily between Linux and Solaris (for easy development and for ground system operations) and VxWorks (for flight systems operations). The exact same source code is exercised in both environments. Initially included in the ION BP implementations are the following: libraries of functions used in constructing bundle forwarders and convergence-layer (CL) input and output adapters; a simple prototype bundle forwarder and associated CL adapters designed to run over an IPbased local area network; administrative tools for managing a simple DTN infrastructure built from these components; a background daemon process that silently destroys bundles whose time-to-live intervals have expired; a library of functions exposed to applications, enabling them to issue and receive data encapsulated in DTN bundles; and some simple applications that can be used for system checkout and benchmarking.

  7. An Alternative Bundle-to-Bundle Suturing Technique for Repairing Fresh Achilles Tendon Rupture.

    PubMed

    Zhao, Jingjing; Yu, Bin; Xie, Ming; Huang, Ruokun; Xiao, Kai

    2016-01-01

    The main concern about conventional Achilles tendon repair surgical techniques is how to maintain the initial strength of the ruptured Achilles tendon through complicated suturing methods. The primary surgical problem lies in the properties of the soft tissue; the deterioration of the Achilles tendon, especially in its elasticity; and the surface lubricity of the local tissues. In the present study, we describe an innovative bundle-to-bundle suturing method that addresses these potential problems. PMID:26970908

  8. Oxidation induced stress-rupture of fiber bundles

    SciTech Connect

    Lara-Curzio, E.

    1997-03-01

    The effect of oxidation on the stress-rupture behavior of fiber bundles was modeled. It is shown that oxidation-induced fiber strength degradation results in the delayed failure of the associated fiber bundle and that the fiber bundle strength decreases with time as t{sup {minus}1/4}. It is also shown that the temperature dependence of the bundle loss of strength reflects the thermal dependence of the mechanism controlling the oxidation of the fibers. The effect of gauge length on the fiber bundle strength was also analyzed. Numerical examples are presented for the special case of Nicalon{trademark} fibers.

  9. Anatomic Double-Bundle Posterior Cruciate Ligament Reconstruction.

    PubMed

    Chahla, Jorge; Nitri, Marco; Civitarese, David; Dean, Chase S; Moulton, Samuel G; LaPrade, Robert F

    2016-02-01

    The posterior cruciate ligament (PCL) is known to be the main posterior stabilizer of the knee. Anatomic single-bundle PCL reconstruction, focusing on reconstruction of the larger anterolateral bundle, is the most commonly performed procedure. Because of the residual posterior and rotational tibial instability after the single-bundle procedure and the inability to restore the normal knee kinematics, an anatomic double-bundle PCL reconstruction has been proposed in an effort to re-create the native PCL footprint more closely and to restore normal knee kinematics. We detail our technique for an anatomic double-bundle PCL reconstruction using Achilles and anterior tibialis tendon allografts. PMID:27284530

  10. Multiwalled carbon nanotube reinforced biomimetic bundled gel fibres.

    PubMed

    Kim, Young-Jin; Yamamoto, Seiichiro; Takahashi, Haruko; Sasaki, Naruo; Matsunaga, Yukiko T

    2016-08-19

    This work describes the fabrication and characterization of hydroxypropyl cellulose (HPC)-based biomimetic bundled gel fibres. The bundled gel fibres were reinforced with multiwalled carbon nanotubes (MWCNTs). A phase-separated aqueous solution with MWCNT and HPC was transformed into a bundled fibrous structure after being injected into a co-flow microfluidic device and applying the sheath flow. The resulting MWCNT-bundled gel fibres consist of multiple parallel microfibres. The mechanical and electrical properties of MWCNT-bundled gel fibres were improved and their potential for tissue engineering applications as a cell scaffold was demonstrated. PMID:27200527

  11. A Comparison between Clinical Results of Selective Bundle and Double Bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Yoo, Yon-Sik; Song, Si Young; Yang, Cheol Jung; Ha, Jong Mun; Kim, Yoon Sang

    2016-01-01

    Purpose The purpose of this study was to compare the clinical outcomes of arthroscopic anatomical double bundle (DB) anterior cruciate ligament (ACL) reconstruction with either selective anteromedial (AM) or posterolateral (PL) bundle reconstruction while preserving a relatively healthy ACL bundle. Materials and Methods The authors evaluated 98 patients with a mean follow-up of 30.8±4.0 months who had undergone DB or selective bundle ACL reconstructions. Of these, 34 cases underwent DB ACL reconstruction (group A), 34 underwent selective AM bundle reconstruction (group B), and 30 underwent selective PL bundle reconstructions (group C). These groups were compared with respect to Lysholm and International Knee Documentation Committee (IKDC) score, side-to-side differences of anterior laxity measured by KT-2000 arthrometer at 30 lbs, and stress radiography and Lachman and pivot shift test results. Pre- and post-operative data were objectively evaluated using a statistical approach. Results The preoperative anterior instability measured by manual stress radiography at 90° of knee flexion in group A was significantly greater than that in groups B and C (all p<0.001). At last follow-up, mean side-to-side instrumented laxities measured by the KT-2000 and manual stress radiography were significantly improved from preoperative data in all groups (all p<0.001). There were no significant differences between the three groups in anterior instability measured by KT-2000 arthrometer, pivot shift, or functional scores. Conclusion Selective bundle reconstruction in partial ACL tears offers comparable clinical results to DB reconstruction in complete ACL tears. PMID:27401652

  12. Emitters of N-photon bundles.

    PubMed

    Muñoz, C Sánchez; Del Valle, E; Tudela, A González; Müller, K; Lichtmannecker, S; Kaniber, M; Tejedor, C; Finley, J J; Laussy, F P

    2014-07-01

    Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or "bundles" of N photons, for integer N. Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state of the art samples. The emission can be tuned with system parameters so that the device behaves as a laser or as a N-photon gun. The theoretical formalism to characterize such emitters is developed, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications. PMID:25013456

  13. Phase Slips in Oscillatory Hair Bundles

    PubMed Central

    Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

    2013-01-01

    Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production. PMID:25167040

  14. Phase slips in oscillatory hair bundles.

    PubMed

    Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

    2013-04-01

    Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production. PMID:25167040

  15. Heterotic String Compactification and New Vector Bundles

    NASA Astrophysics Data System (ADS)

    Lin, Hai; Wu, Baosen; Yau, Shing-Tung

    2016-07-01

    We propose a construction of Kähler and non-Kähler Calabi-Yau manifolds by branched double covers of twistor spaces. In this construction we use the twistor spaces of four-manifolds with self-dual conformal structures, with the examples of connected sum of n {mathbb{P}2}s. We also construct K3-fibered Calabi-Yau manifolds from the branched double covers of the blow-ups of the twistor spaces. These manifolds can be used in heterotic string compactifications to four dimensions. We also construct stable and polystable vector bundles. Some classes of these vector bundles can give rise to supersymmetric grand unified models with three generations of quarks and leptons in four dimensions.

  16. Covariance and the hierarchy of frame bundles

    NASA Technical Reports Server (NTRS)

    Estabrook, Frank B.

    1987-01-01

    This is an essay on the general concept of covariance, and its connection with the structure of the nested set of higher frame bundles over a differentiable manifold. Examples of covariant geometric objects include not only linear tensor fields, densities and forms, but affinity fields, sectors and sector forms, higher order frame fields, etc., often having nonlinear transformation rules and Lie derivatives. The intrinsic, or invariant, sets of forms that arise on frame bundles satisfy the graded Cartan-Maurer structure equations of an infinite Lie algebra. Reduction of these gives invariant structure equations for Lie pseudogroups, and for G-structures of various orders. Some new results are introduced for prolongation of structure equations, and for treatment of Riemannian geometry with higher-order moving frames. The use of invariant form equations for nonlinear field physics is implicitly advocated.

  17. Phase Slips in Oscillatory Hair Bundles

    NASA Astrophysics Data System (ADS)

    Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

    2013-04-01

    Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production.

  18. Are Medicare bundles in your future?

    PubMed

    Mulvany, Chad

    2015-08-01

    To ensure they are well-positioned for an expansion by the Centers for Medicare & Medicaid Services of bundled payment, hospitals that are not participants in the Bundled Payments for Care Improvement initiative should take the following steps: Understand which organizations in their markets are already participating and which might participate. Understand care utilization patterns within their care delivery networks and how those patterns affect cost per episode. Identify high-quality, cost-efficient postacute care providers and begin collaborating with them to further improve outcomes. Educate discharging physicians about the impact that choices related to postacute settings have on both beneficiary out-of-pocket obligations and overall cost of care. PMID:26548136

  19. Heterotic String Compactification and New Vector Bundles

    NASA Astrophysics Data System (ADS)

    Lin, Hai; Wu, Baosen; Yau, Shing-Tung

    2016-06-01

    We propose a construction of Kähler and non-Kähler Calabi-Yau manifolds by branched double covers of twistor spaces. In this construction we use the twistor spaces of four-manifolds with self-dual conformal structures, with the examples of connected sum of n {P2} s. We also construct K3-fibered Calabi-Yau manifolds from the branched double covers of the blow-ups of the twistor spaces. These manifolds can be used in heterotic string compactifications to four dimensions. We also construct stable and polystable vector bundles. Some classes of these vector bundles can give rise to supersymmetric grand unified models with three generations of quarks and leptons in four dimensions.

  20. Hierarchical scaling law for the strength of composite fibre bundles

    NASA Astrophysics Data System (ADS)

    Pimenta, Soraia; Pinho, Silvestre T.

    2013-06-01

    This paper presents an analytical model for size effects on the longitudinal tensile strength of composite fibre bundles. The strength of individual fibres is modelled by a Weibull distribution, while the matrix (or fibre-matrix interface) is represented through a perfectly plastic shear-lag model. A probabilistic analysis of the failure process in hierarchical bundles (bundles of bundles) is performed, so that a scaling law relating the strength distributions and characteristic lengths of consecutive bundle levels is derived. An efficient numerical scheme (based on asymptotic limits) is proposed, hence coupon-sized bundle strength distributions are obtained almost instantaneously. Parametric studies show that both fibre and matrix properties are critical for bundle strength; model predictions at different scales are validated against experimental results available in the literature.

  1. Radiological evidence for the triple bundle anterior cruciate ligament.

    PubMed

    MacKay, James W; Whitehead, Harry; Toms, Andoni P

    2014-10-01

    The anterior cruciate ligament (ACL) has traditionally been described as having two bundles--one anteromedial and one posterolateral. This has been challenged by studies proposing the existence of a third, intermediate, bundle with distinct functional significance, an arrangement that has been described in a number of domesticated animal species. No radiological evidence for the triple bundle ACL has previously been described. A prevalence study was carried out on 73 consecutive human knee magnetic resonance (MR) studies to determine the number of visible bundles, excluding individuals with a history of ACL injury or mucoid degeneration. A triple bundle ACL was demonstrated in 15 out of 73 human knees (20.5%, 95% confidence interval 12.9-31.2%). This is the first radiological description of the human triple bundle ACL. There was MR imaging evidence of a triple bundle ACL in approximately one fifth of human knees in this study. PMID:24890455

  2. Uncovering Ecosystem Service Bundles through Social Preferences

    PubMed Central

    Martín-López, Berta; Iniesta-Arandia, Irene; García-Llorente, Marina; Palomo, Ignacio; Casado-Arzuaga, Izaskun; Amo, David García Del; Gómez-Baggethun, Erik; Oteros-Rozas, Elisa; Palacios-Agundez, Igone; Willaarts, Bárbara; González, José A.; Santos-Martín, Fernando; Onaindia, Miren; López-Santiago, Cesar; Montes, Carlos

    2012-01-01

    Ecosystem service assessments have increasingly been used to support environmental management policies, mainly based on biophysical and economic indicators. However, few studies have coped with the social-cultural dimension of ecosystem services, despite being considered a research priority. We examined how ecosystem service bundles and trade-offs emerge from diverging social preferences toward ecosystem services delivered by various types of ecosystems in Spain. We conducted 3,379 direct face-to-face questionnaires in eight different case study sites from 2007 to 2011. Overall, 90.5% of the sampled population recognized the ecosystem’s capacity to deliver services. Formal studies, environmental behavior, and gender variables influenced the probability of people recognizing the ecosystem’s capacity to provide services. The ecosystem services most frequently perceived by people were regulating services; of those, air purification held the greatest importance. However, statistical analysis showed that socio-cultural factors and the conservation management strategy of ecosystems (i.e., National Park, Natural Park, or a non-protected area) have an effect on social preferences toward ecosystem services. Ecosystem service trade-offs and bundles were identified by analyzing social preferences through multivariate analysis (redundancy analysis and hierarchical cluster analysis). We found a clear trade-off among provisioning services (and recreational hunting) versus regulating services and almost all cultural services. We identified three ecosystem service bundles associated with the conservation management strategy and the rural-urban gradient. We conclude that socio-cultural preferences toward ecosystem services can serve as a tool to identify relevant services for people, the factors underlying these social preferences, and emerging ecosystem service bundles and trade-offs. PMID:22720006

  3. Alpha1 LASSO data bundles Lamont, OK

    DOE Data Explorer

    Gustafson, William Jr; Vogelmann, Andrew; Endo, Satoshi; Toto, Tami; Xiao, Heng; Li, Zhijin; Cheng, Xiaoping; Krishna, Bhargavi (ORCID:000000018828528X)

    2016-08-03

    A data bundle is a unified package consisting of LASSO LES input and output, observations, evaluation diagnostics, and model skill scores. LES input includes model configuration information and forcing data. LES output includes profile statistics and full domain fields of cloud and environmental variables. Model evaluation data consists of LES output and ARM observations co-registered on the same grid and sampling frequency. Model performance is quantified by skill scores and diagnostics in terms of cloud and environmental variables.

  4. Stable vector bundles and string theory

    SciTech Connect

    Gomez, Tomas L.; Sols, Ignacio; Lukic, Sergio

    2009-05-06

    In [4], Braun, He, Ovrut and Pantev proposed a model of string theory (based on the Calabi-Yau 3-fold X) whose low energy limit predicts certain properties of the Standard Model of particle Physics. This model depends on two vector bundles that have to be stable. We calculate the ample cone of X, and prove that one of them is stable, and the other one is not.

  5. End-of-life nondestructive examination of Light Water Breeder Reactor fuel rods (LWBR Development Program)

    SciTech Connect

    Gorscak, D.A.; Campbell, W.R.; Clayton, J.C.

    1987-10-01

    In-bundle and out-of-bundle (single rod) nondestructive examinations of Light Water Breeder Reactor fuel rods were performed. In-bundle examinations included visual examination and measurement of rod bow, rod-to-rod gaps, and rod removal forces. Out-of-bundle examinations included rod visuals and measurement of fuel rod length, diameter and ovality, cladding oxide and crud thickness, support grid induced cladding wear mark depth and volume, and fuel rod free hanging bow. The out-of-bundle examination also included ultrasonic inspection for cladding defects, neutron radiography for pellet integrity and plenum gap measurements, and gamma scans for instack axial gap screening and binary fuel stack length measurements. The measurements confirmed design predictions of fuel rod performance and provided evidence of excellent fuel rod performance for operation of Light Water Breeder Reactor to 29,047 effective full power hours (EFPH).

  6. An analytical fiber bundle model for pullout mechanics of root bundles

    NASA Astrophysics Data System (ADS)

    Cohen, D.; Schwarz, M.; Or, D.

    2011-09-01

    Roots in soil contribute to the mechanical stability of slopes. Estimation of root reinforcement is challenging because roots form complex biological networks whose geometrical and mechanical characteristics are difficult to characterize. Here we describe an analytical model that builds on simple root descriptors to estimate root reinforcement. Root bundles are modeled as bundles of heterogeneous fibers pulled along their long axes neglecting root-soil friction. Analytical expressions for the pullout force as a function of displacement are derived. The maximum pullout force and corresponding critical displacement are either derived analytically or computed numerically. Key model inputs are a root diameter distribution (uniform, Weibull, or lognormal) and three empirical power law relations describing tensile strength, elastic modulus, and length of roots as functions of root diameter. When a root bundle with root tips anchored in the soil matrix is pulled by a rigid plate, a unique parameter, ?, that depends only on the exponents of the power law relations, dictates the order in which roots of different diameters break. If ? < 1, small roots break first; if ? > 1, large roots break first. When ? = 1, all fibers break simultaneously, and the maximum tensile force is simply the roots' mean force times the number of roots in the bundle. Based on measurements of root geometry and mechanical properties, the value of ? is less than 1, usually ranging between 0 and 0.7. Thus, small roots always fail first. The model shows how geometrical and mechanical characteristics of roots and root diameter distribution affect the pullout force, its maximum and corresponding displacement. Comparing bundles of roots that have similar mean diameters, a bundle with a narrow variance in root diameter will result in a larger maximum force and a smaller displacement at maximum force than a bundle with a wide diameter distribution. Increasing the mean root diameter of a bundle without

  7. Bundled payment fails to gain a foothold In California: the experience of the IHA bundled payment demonstration.

    PubMed

    Ridgely, M Susan; de Vries, David; Bozic, Kevin J; Hussey, Peter S

    2014-08-01

    To determine whether bundled payment could be an effective payment model for California, the Integrated Healthcare Association convened a group of stakeholders (health plans, hospitals, ambulatory surgery centers, physician organizations, and vendors) to develop, through a consensus process, the methods and means of implementing bundled payment. In spite of a high level of enthusiasm and effort, the pilot did not succeed in its goal to implement bundled payment for orthopedic procedures across multiple payers and hospital-physician partners. An evaluation of the pilot documented a number of barriers, such as administrative burden, state regulatory uncertainty, and disagreements about bundle definition and assumption of risk. Ultimately, few contracts were signed, which resulted in insufficient volume to test hypotheses about the impact of bundled payment on quality and costs. Although bundled payment failed to gain a foothold in California, the evaluation provides lessons for future bundled payment initiatives. PMID:25092835

  8. Force-generation and dynamic instability of microtubule bundles

    PubMed Central

    Laan, Liedewij; Husson, Julien; Munteanu, E. Laura; Kerssemakers, Jacob W. J.; Dogterom, Marileen

    2008-01-01

    Individual dynamic microtubules can generate pushing or pulling forces when their growing or shrinking ends are in contact with cellular objects such as the cortex or chromosomes. These microtubules can operate in parallel bundles, for example when interacting with mitotic chromosomes. Here, we investigate the force-generating capabilities of a bundle of growing microtubules and study the effect that force has on the cooperative dynamics of such a bundle. We used an optical tweezers setup to study microtubule bundles growing against a microfabricated rigid barrier in vitro. We show that multiple microtubules can generate a pushing force that increases linearly with the number of microtubules present. In addition, the bundle can cooperatively switch to a shrinking state, due to a force-induced coupling of the dynamic instability of single microtubules. In the presence of GMPCPP, bundle catastrophes no longer occur, and high bundle forces are reached more effectively. We reproduce the observed behavior with a simple simulation of microtubule bundle dynamics that takes into account previously measured force effects on single microtubules. Using this simulation, we also show that a constant compressive force on a growing bundle leads to oscillations in bundle length that are of potential relevance for chromosome oscillations observed in living cells. PMID:18577596

  9. Combustor and method for distributing fuel in the combustor

    DOEpatents

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; York, William David

    2016-04-26

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface. A plurality of tubes extends from the upstream surface through the downstream surface, and each tube provides fluid communication through the tube bundle. A baffle extends axially inside the tube bundle between adjacent tubes. A method for distributing fuel in a combustor includes flowing a fuel into a fuel plenum defined at least in part by an upstream surface, a downstream surface, a shroud, and a plurality of tubes that extend from the upstream surface to the downstream surface. The method further includes impinging the fuel against a baffle that extends axially inside the fuel plenum between adjacent tubes.

  10. Fluid-mixing studies in a hexagonal 217-pin wire-wrapped rod bundle. [LMFBR

    SciTech Connect

    Symolon, P.D.; Todreas, N.E.

    1981-02-01

    Mixing, pressure drop, and flow split experiments were performed on a 217 pin LMFBR fuel bundle with a pitch to diameter ratio of 1.25 and a lead length of 12 inches. It was found that the turbulent flow data could best be characterized by the energy parameter C/sub 1L/=.106, which is 9% higher than the value from the correlation of Chiu et al. Chiu's correlation was developed on a data base of 61 and 91 pins. The spread of existing data about the correlation is +- 25%, but the error band on our data is expected to be less (approx. +- 10% since injection depth effects were not previously considered). This result is consistent with the concept of increased swirl flow in larger bundles (more pins).

  11. Numerical Simulation of Boiling Two-Phase Flow in Tight-Lattice Rod Bundle by 3-Dimensional Two-Fluid Model Code ACE-3D

    NASA Astrophysics Data System (ADS)

    Yoshida, Hiroyuki; Misawa, Takeharu; Takase, Kazuyuki

    Two-fluid model can simulate two-phase flow by computational cost less than detailed two-phase flow simulation method such as interface tracking method or particle interaction method. Therefore, two-fluid model is useful for thermal hydraulic analysis in large-scale domain such as a rod bundle. Japan Atomic Energy Agency (JAEA) develops three dimensional two-fluid model analysis code ACE-3D that adopts boundary fitted coordinate system in order to simulate complex shape flow channel. In this paper, boiling two-phase flow analysis in a tight-lattice rod bundle was performed by ACE-3D code. The parallel computation using 126 CPUs was applied to this analysis. In the results, the void fraction, which distributes in outermost region of rod bundle, is lower than that in center region of rod bundle. The tendency of void fraction distribution agreed with the measurement results by neutron radiography qualitatively. To evaluate effects of two-phase flow model used in ACE-3D code, numerical simulation of boiling two-phase in tight-lattice rod bundle with no lift force model was also performed. From the comparison of calculated results, it was concluded that the effects of lift force model were not so large for overall void fraction distribution of tight-lattice rod bundle. However, the lift force model is important for local void fraction distribution of fuel bundles.

  12. Synchronization of Spontaneous Active Motility of Hair Cell Bundles

    PubMed Central

    Zhang, Tracy-Ying; Ji, Seung; Bozovic, Dolores

    2015-01-01

    Hair cells of the inner ear exhibit an active process, believed to be crucial for achieving the sensitivity of auditory and vestibular detection. One of the manifestations of the active process is the occurrence of spontaneous hair bundle oscillations in vitro. Hair bundles are coupled by overlying membranes in vivo; hence, explaining the potential role of innate bundle motility in the generation of otoacoustic emissions requires an understanding of the effects of coupling on the active bundle dynamics. We used microbeads to connect small groups of hair cell bundles, using in vitro preparations that maintain their innate oscillations. Our experiments demonstrate robust synchronization of spontaneous oscillations, with either 1:1 or multi-mode phase-locking. The frequency of synchronized oscillation was found to be near the mean of the innate frequencies of individual bundles. Coupling also led to an improved regularity of entrained oscillations, demonstrated by an increase in the quality factor. PMID:26540409

  13. Synchronization of Spontaneous Active Motility of Hair Cell Bundles.

    PubMed

    Zhang, Tracy-Ying; Ji, Seung; Bozovic, Dolores

    2015-01-01

    Hair cells of the inner ear exhibit an active process, believed to be crucial for achieving the sensitivity of auditory and vestibular detection. One of the manifestations of the active process is the occurrence of spontaneous hair bundle oscillations in vitro. Hair bundles are coupled by overlying membranes in vivo; hence, explaining the potential role of innate bundle motility in the generation of otoacoustic emissions requires an understanding of the effects of coupling on the active bundle dynamics. We used microbeads to connect small groups of hair cell bundles, using in vitro preparations that maintain their innate oscillations. Our experiments demonstrate robust synchronization of spontaneous oscillations, with either 1:1 or multi-mode phase-locking. The frequency of synchronized oscillation was found to be near the mean of the innate frequencies of individual bundles. Coupling also led to an improved regularity of entrained oscillations, demonstrated by an increase in the quality factor. PMID:26540409

  14. Mechanics of Individual Keratin Bundles in Living Cells

    PubMed Central

    Nolting, Jens-Friedrich; Möbius, Wiebke; Köster, Sarah

    2014-01-01

    Along with microtubules and microfilaments, intermediate filaments are a major component of the eukaryotic cytoskeleton and play a key role in cell mechanics. In cells, keratin intermediate filaments form networks of bundles that are sparser in structure and have lower connectivity than, for example, actin networks. Because of this, bending and buckling play an important role in these networks. Buckling events, which occur due to compressive intracellular forces and cross-talk between the keratin network and other cytoskeletal components, are measured here in situ. By applying a mechanical model for the bundled filaments, we can access the mechanical properties of both the keratin bundles themselves and the surrounding cytosol. Bundling is characterized by a coupling parameter that describes the strength of the linkage between the individual filaments within a bundle. Our findings suggest that coupling between the filaments is mostly complete, although it becomes weaker for thicker bundles, with some relative movement allowed. PMID:25468348

  15. The proteome of mouse vestibular hair bundles over development

    PubMed Central

    Krey, Jocelyn F.; Sherman, Nicholas E.; Jeffery, Erin D; Choi, Dongseok; Barr-Gillespie, Peter G.

    2015-01-01

    Development of the vertebrate hair bundle is a precisely orchestrated event that culminates in production of a tightly ordered arrangement of actin-rich stereocilia and a single axonemal kinocilium. To understand how the protein composition of the bundle changes during development, we isolated bundles from young (postnatal days P4-P6) and mature (P21-P25) mouse utricles using the twist-off method, then characterized their constituent proteins using liquid-chromatography tandem mass spectrometry with data-dependent acquisition. Using MaxQuant and label-free quantitation, we measured relative abundances of proteins in both bundles and in the whole utricle; comparison of protein abundance between the two fractions allows calculation of enrichment in bundles. These data, which are available via ProteomeXchange with identifier PXD002167, will be useful for examining the proteins present in mammalian vestibular bundles and how their concentrations change over development. PMID:26401315

  16. Historical dynamics in ecosystem service bundles.

    PubMed

    Renard, Delphine; Rhemtulla, Jeanine M; Bennett, Elena M

    2015-10-27

    Managing multiple ecosystem services (ES), including addressing trade-offs between services and preventing ecological surprises, is among the most pressing areas for sustainability research. These challenges require ES research to go beyond the currently common approach of snapshot studies limited to one or two services at a single point in time. We used a spatiotemporal approach to examine changes in nine ES and their relationships from 1971 to 2006 across 131 municipalities in a mixed-use landscape in Quebec, Canada. We show how an approach that incorporates time and space can improve our understanding of ES dynamics. We found an increase in the provision of most services through time; however, provision of ES was not uniformly enhanced at all locations. Instead, each municipality specialized in providing a bundle (set of positively correlated ES) dominated by just a few services. The trajectory of bundle formation was related to changes in agricultural policy and global trends; local biophysical and socioeconomic characteristics explained the bundles' increasing spatial clustering. Relationships between services varied through time, with some provisioning and cultural services shifting from a trade-off or no relationship in 1971 to an apparent synergistic relationship by 2006. By implementing a spatiotemporal perspective on multiple services, we provide clear evidence of the dynamic nature of ES interactions and contribute to identifying processes and drivers behind these changing relationships. Our study raises questions about using snapshots of ES provision at a single point in time to build our understanding of ES relationships in complex and dynamic social-ecological systems. PMID:26460005

  17. Systematic Bundle Adjustment of HRSC Image Data

    NASA Astrophysics Data System (ADS)

    Bostelmann, J.; Schmidt, R.; Heipke, C.

    2012-07-01

    The European Mars Express mission was launched in June 2003 and sent into orbit around Mars. On board the orbiter is the German High Resolution Stereo Camera (HRSC). This multi-line sensor images the Martian surface with a resolution of up to 12m per pixel in three dimensions and provides RGB and infra-red color information. The usage of the stereoscopic image information for the improvement of the observed position and attitude information via bundle adjustment is important to derive high quality 3D surface models, color orthoimages and other data products. In many cases overlapping image strips of different orbits can be used to form photogrammetric blocks, thus allowing the simultaneous adjustment of the exterior orientation data. This reduces not only local, but also regional inconsistencies in the data. With the growing number of HRSC image strips in this ongoing mission, the size and complexity of potential blocks is increasing. Therefore, a workflow has been built up for the systematic improvement of the exterior orientation using single orbit strips and regional blocks. For a successful bundle adjustment of blocks using multiple image strips a sufficient number of tie points in the overlapping area is needed. The number of tie points depends mainly on the geometric and radiometric quality of the images. This is considered by detailed analysis of the tie point accuracy and distribution. The combination of methods for image pre-processing, tie point matching, bundle adjustment and evaluation of the results in an automated workflow allows for all HRSC images a global assessment of the quality and a systematic selection of data for larger blocks.

  18. Chemical vapor infiltration of carbon fiber bundles

    SciTech Connect

    Currier, R.P.; Devlin, D.J.; Barbero, R.S.

    1992-12-31

    Chemical vapor infiltration in carbon fiber bundles is studied under isothermal conditions over the temperature range 1000--1090 C at a nominal pressure of 300 Torr. Pyrolytic decomposition of methane is used in the infiltration experiments with carbon weight gain data obtained continuously from thermogravimetric analysis. The sensitivity of the infiltration dynamics to initial yarn porosity and to spatial variations in fiber positioning are explored. Results indicate that small changes in initial porosity can have significant impact on the weight gain above the solid phase percolation threshold.

  19. Chemical vapor infiltration of carbon fiber bundles

    SciTech Connect

    Currier, R.P.; Devlin, D.J.; Barbero, R.S.

    1992-01-01

    Chemical vapor infiltration in carbon fiber bundles is studied under isothermal conditions over the temperature range 1000--1090 C at a nominal pressure of 300 Torr. Pyrolytic decomposition of methane is used in the infiltration experiments with carbon weight gain data obtained continuously from thermogravimetric analysis. The sensitivity of the infiltration dynamics to initial yarn porosity and to spatial variations in fiber positioning are explored. Results indicate that small changes in initial porosity can have significant impact on the weight gain above the solid phase percolation threshold.

  20. Compression of a bundle of light rays.

    PubMed

    Marcuse, D

    1971-03-01

    The performance of ray compression devices is discussed on the basis of a phase space treatment using Liouville's theorem. It is concluded that the area in phase space of the input bundle of rays is determined solely by the required compression ratio and possible limitations on the maximum ray angle at the output of the device. The efficiency of tapers and lenses as ray compressors is approximately equal. For linear tapers and lenses the input angle of the useful rays must not exceed the compression ratio. The performance of linear tapers and lenses is compared to a particular ray compressor using a graded refractive index distribution. PMID:20094478

  1. Bohr-Sommerfeld Lagrangians of moduli spaces of Higgs bundles

    NASA Astrophysics Data System (ADS)

    Biswas, Indranil; Gammelgaard, Niels Leth; Logares, Marina

    2015-08-01

    Let X be a compact connected Riemann surface of genus at least two. Let MH(r, d) denote the moduli space of semistable Higgs bundles on X of rank r and degree d. We prove that the compact complex Bohr-Sommerfeld Lagrangians of MH(r, d) are precisely the irreducible components of the nilpotent cone in MH(r, d) . This generalizes to Higgs G-bundles and also to the parabolic Higgs bundles.

  2. COBRA-PI: an extension of the COBRA-3M code dynamically dimensioned to accept pin bundles of any size. [LMFBR

    SciTech Connect

    Froehle, P.H.; Bauer, T.H.

    1983-03-28

    COBRA, in general, performs a thermal-hydraulic analysis of an actual pin bundle by subdividing the bundle cross-section into coolant subchannels, pin sectors, duct wall sectors. Its calculation includes heat convected axially upward through coolant mass flow, heat flow between pin sectors and adjoining subchannels, and heat and mass flow between coolant subchannels. COBRA-3M is a version of COBRA built for LMFBR applications, that includes a sophisticated thermal model of fuel pins and duct wall. COBRA-3M that can explicitly model a wider variety of pin bundle configurations than 3M would allow and includes significant improvements to its thermal modeling. COBRA-PI is currently being used for thermal-hydraulic analysis of hypothetical LMFBR accident transients in both power and flow. Pin bundles currently being analyzed explicitly range from 7 to 37 pins of axial lengths ranging from approx. 0.3-2.0 meters.

  3. Robust Mapping of Incoherent Fiber-Optic Bundles

    NASA Technical Reports Server (NTRS)

    Roberts, Harry E.; Deason, Brent E.; DePlachett, Charles P.; Pilgrim, Robert A.; Sanford, Harold S.

    2007-01-01

    A method and apparatus for mapping between the positions of fibers at opposite ends of incoherent fiber-optic bundles have been invented to enable the use of such bundles to transmit images in visible or infrared light. The method is robust in the sense that it provides useful mapping even for a bundle that contains thousands of narrow, irregularly packed fibers, some of which may be defective. In a coherent fiber-optic bundle, the input and output ends of each fiber lie at identical positions in the input and output planes; therefore, the bundle can be used to transmit images without further modification. Unfortunately, the fabrication of coherent fiber-optic bundles is too labor-intensive and expensive for many applications. An incoherent fiber-optic bundle can be fabricated more easily and at lower cost, but it produces a scrambled image because the position of the end of each fiber in the input plane is generally different from the end of the same fiber in the output plane. However, the image transmitted by an incoherent fiber-optic bundle can be unscrambled (or, from a different perspective, decoded) by digital processing of the output image if the mapping between the input and output fiber-end positions is known. Thus, the present invention enables the use of relatively inexpensive fiber-optic bundles to transmit images.

  4. Force-strain relation of bundles of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Xiao, Tan; Ren, Yu; Wu, Ping; Liao, Kin

    2006-07-01

    The force-strain relation and tensile strength of carbon nanotube bundles are studied based on the assumption that the tensile strength of individual carbon nanotubes (CNTs) obeys the Weibull distribution, with nonlinear stress-strain behavior. The Weibull modulus of the CNT that characterizes the dispersion of tensile strength can be estimated in terms of the maximum sustained force and the failure strain of the bundle. Bundles of single-walled carbon nanotubes (SWNTs) were subjected to tensile testing using a nanomechanical testing device. Results show that the nonlinear behavior of SWNTs does affect the force-strain relation of SWNT bundles, more apparent at large strain.

  5. Bundle formation in parallel aligned polymers with competing interactions

    NASA Astrophysics Data System (ADS)

    Dutta, Sandipan; Benetatos, P.; Jho, Y. S.

    2016-04-01

    Aggregation of like-charged polymers is widely observed in biological- and soft-matter systems. In many systems, bundles are formed when a short-range attraction of diverse physical origin like charge bridging, hydrogen bonding or hydrophobic interaction, overcomes the longer-range charge repulsion. In this letter, we present a general mechanism of bundle formation in these systems as the breaking of the translational invariance in parallel aligned polymers with competing interactions of this type. We derive a criterion for finite-sized bundle formation as well as for macroscopic phase separation (formation of infinite bundles).

  6. Constrained ripple optimization of Tokamak bundle divertors

    SciTech Connect

    Hively, L.M.; Rome, J.A.; Lynch, V.E.; Lyon, J.F.; Fowler, R.H.; Peng, Y-K.M.; Dory, R.A.

    1983-02-01

    Magnetic field ripple from a tokamak bundle divertor is localized to a small toroidal sector and must be treated differently from the usual (distributed) toroidal field (TF) coil ripple. Generally, in a tokamak with an unoptimized divertor design, all of the banana-trapped fast ions are quickly lost due to banana drift diffusion or to trapping between the 1/R variation in absolute value vector B ..xi.. B and local field maxima due to the divertor. A computer code has been written to optimize automatically on-axis ripple subject to these constraints, while varying up to nine design parameters. Optimum configurations have low on-axis ripple (<0.2%) so that, now, most banana-trapped fast ions are confined. Only those ions with banana tips near the outside region (absolute value theta < or equal to 45/sup 0/) are lost. However, because finite-sized TF coils have not been used in this study, the flux bundle is not expanded.

  7. Tangent Bundle Elastica and Computer Vision.

    PubMed

    Ben-Shahar, Ohad; Ben-Yosef, Guy

    2015-01-01

    Visual curve completion, an early visual process that completes the occluded parts between observed boundary fragments (a.k.a. inducers), is a major problem in perceptual organization and a critical step toward higher level visual tasks in both biological and machine vision. Most computational contributions to solving this problem suggest desired perceptual properties that the completed contour should satisfy in the image plane, and then seek the mathematical curves that provide them. Alternatively, few studies (including by the authors) have suggested to frame the problem not in the image plane but rather in the unit tangent bundleR (2) × S(1), the space that abstracts the primary visual cortex, where curve completion allegedly occurs. Combining both schools, here we propose and develop a biologically plausible theory of elastica in the tangent bundle that provides not only perceptually superior completion results but also a rigorous computational prediction that inducer curvatures greatly affects the shape of the completed curve, as indeed indicated by human perception. PMID:26353216

  8. Development boiling to sprinkled tube bundle

    NASA Astrophysics Data System (ADS)

    Kracík, Petr; Pospíšil, Jiří

    2016-03-01

    This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes' interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

  9. Emitters of N-photon bundles

    NASA Astrophysics Data System (ADS)

    Muñoz, C. Sánchez; Del Valle, E.; Tudela, A. González; Müller, K.; Lichtmannecker, S.; Kaniber, M.; Tejedor, C.; Finley, J. J.; Laussy, F. P.

    2014-07-01

    Controlling the output of a light emitter is one of the basic tasks in photonics, with landmarks such as the development of the laser and single-photon sources. The ever growing range of quantum applications is making it increasingly important to diversify the available quantum sources. Here, we propose a cavity quantum electrodynamics scheme to realize emitters that release their energy in groups (or `bundles') of N photons (where N is an integer). Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state-of-the-art samples. The emission can be tuned with the system parameters so that the device behaves as a laser or as an N-photon gun. Here, we develop the theoretical formalism to characterize such emitters, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications.

  10. Confinement-dependent friction in peptide bundles.

    PubMed

    Erbaş, Aykut; Netz, Roland R

    2013-03-19

    Friction within globular proteins or between adhering macromolecules crucially determines the kinetics of protein folding, the formation, and the relaxation of self-assembled molecular systems. One fundamental question is how these friction effects depend on the local environment and in particular on the presence of water. In this model study, we use fully atomistic MD simulations with explicit water to obtain friction forces as a single polyglycine peptide chain is pulled out of a bundle of k adhering parallel polyglycine peptide chains. The whole system is periodically replicated along the peptide axes, so a stationary state at prescribed mean sliding velocity V is achieved. The aggregation number is varied between k = 2 (two peptide chains adhering to each other with plenty of water present at the adhesion sites) and k = 7 (one peptide chain pulled out from a close-packed cylindrical array of six neighboring peptide chains with no water inside the bundle). The friction coefficient per hydrogen bond, extrapolated to the viscous limit of vanishing pulling velocity V → 0, exhibits an increase by five orders of magnitude when going from k = 2 to k = 7. This dramatic confinement-induced friction enhancement we argue to be due to a combination of water depletion and increased hydrogen-bond cooperativity. PMID:23528088

  11. Positioning and locking device for fuel pin to grid attachment

    DOEpatents

    Frick, Thomas M.; Wineman, Arthur L.

    1976-01-01

    A positioning and locking device for fuel pin to grid attachment provides an inexpensive means of positively positioning and locking the individual fuel pins which make up the driver fuel assemblies used in nuclear reactors. The device can be adapted for use with a currently used attachment grid assembly design and insures that the pins remain in their proper position throughout the in-reactor life of the assembly. This device also simplifies fuel bundle assembly in that a complete row of fuel pins can be added to the bundle during each step of assembly.

  12. Hair bundle profiles along the chick basilar papilla

    PubMed Central

    DUNCAN, R. K.; ILE, K. E.; DUBIN, M. G.; SAUNDERS, J. C.

    2001-01-01

    Cochlear hair cells play a central role in the transduction of sound into neural output. Anatomical descriptions of these cells, and their protruding hair bundles, are of fundamental interest since hair cell transduction is dependent on hair bundle micromechanics and hair bundle micromechanics depends on hair bundle morphology. In this paper, we describe quantitatively changes in the staircase profile of the hair bundle along the apical portion of the chick's basilar papilla. Images of hair cells from 8 discretely dissected segments of the apical 3rd of the basilar papilla were archived, and the profile contour outlined by the tips of the stereocilia was digitised and curves were fitted by linear and power equations. The hair bundles of tall hair cells exhibited both linear and curvilinear profiles, which were equally distributed along the papilla. All short hair cells in our sample had straight contours. The differences in hair bundle shape among the tall hair cells may lead to differential susceptibility to injury and some variance in the current-displacement transduction curves due to differences in the translation of forces throughout the hair bundle. PMID:11215761

  13. Molecular Architecture of the Chick Vestibular Hair Bundle

    PubMed Central

    Shin, Jung-Bum; Krey, Jocelyn F.; Hassan, Ahmed; Metlagel, Zoltan; Tauscher, Andrew N.; Pagana, James M.; Sherman, Nicholas E.; Jeffery, Erin D.; Spinelli, Kateri J.; Zhao, Hongyu; Wilmarth, Phillip A.; Choi, Dongseok; David, Larry L.; Auer, Manfred; Barr-Gillespie, Peter G.

    2012-01-01

    Hair bundles of the inner ear have a unique structure and protein composition that underlies their sensitivity to mechanical stimulation. Using mass spectrometry, we identified and quantified >1100 proteins, present from a few to 400,000 copies per stereocilium, from purified chick bundles; 336 of these were significantly enriched in bundles. Bundle proteins that we detected have been shown to regulate cytoskeleton structure and dynamics, energy metabolism, phospholipid synthesis, and cell signaling. Three-dimensional imaging using electron tomography allowed us to count the number of actin-actin crosslinkers and actin-membrane connectors; these values compared well to those obtained from mass spectrometry. Network analysis revealed several hub proteins, including RDX (radixin) and SLC9A3R2 (NHERF2), which interact with many bundle proteins and may perform functions essential for bundle structure and function. The quantitative mass spectrometry of bundle proteins reported here establishes a framework for future characterization of dynamic processes that shape bundle structure and function. PMID:23334578

  14. Molecular architecture of the chick vestibular hair bundle.

    PubMed

    Shin, Jung-Bum; Krey, Jocelyn F; Hassan, Ahmed; Metlagel, Zoltan; Tauscher, Andrew N; Pagana, James M; Sherman, Nicholas E; Jeffery, Erin D; Spinelli, Kateri J; Zhao, Hongyu; Wilmarth, Phillip A; Choi, Dongseok; David, Larry L; Auer, Manfred; Barr-Gillespie, Peter G

    2013-03-01

    Hair bundles of the inner ear have a specialized structure and protein composition that underlies their sensitivity to mechanical stimulation. Using mass spectrometry, we identified and quantified >1,100 proteins, present from a few to 400,000 copies per stereocilium, from purified chick bundles; 336 of these were significantly enriched in bundles. Bundle proteins that we detected have been shown to regulate cytoskeleton structure and dynamics, energy metabolism, phospholipid synthesis and cell signaling. Three-dimensional imaging using electron tomography allowed us to count the number of actin-actin cross-linkers and actin-membrane connectors; these values compared well to those obtained from mass spectrometry. Network analysis revealed several hub proteins, including RDX (radixin) and SLC9A3R2 (NHERF2), which interact with many bundle proteins and may perform functions essential for bundle structure and function. The quantitative mass spectrometry of bundle proteins reported here establishes a framework for future characterization of dynamic processes that shape bundle structure and function. PMID:23334578

  15. Amplitude death of coupled hair bundles with stochastic channel noise

    NASA Astrophysics Data System (ADS)

    Kim, Kyung-Joong; Ahn, Kang-Hun

    2014-04-01

    Hair cells conduct auditory transduction in vertebrates. In lower vertebrates such as frogs and turtles, due to the active mechanism in hair cells, hair bundles (stereocilia) can be spontaneously oscillating or quiescent. Recently an amplitude death phenomenon has been proposed [K.-H. Ahn, J. R. Soc. Interface, 10, 20130525 (2013)] as a mechanism for auditory transduction in frog hair-cell bundles, where sudden cessation of the oscillations arises due to the coupling between nonidentical hair bundles. The gating of the ion channel is intrinsically stochastic due to the stochastic nature of the configuration change of the channel. The strength of the noise due to the channel gating can be comparable to the thermal Brownian noise of hair bundles. Thus, we perform stochastic simulations of the elastically coupled hair bundles. In spite of stray noisy fluctuations due to its stochastic dynamics, our simulation shows the transition from collective oscillation to amplitude death as interbundle coupling strength increases. In its stochastic dynamics, the formation of the amplitude death state of coupled hair bundles can be seen as a sudden suppression of the displacement fluctuation of the hair bundles as the coupling strength increases. The enhancement of the signal-to-noise ratio through the amplitude death phenomenon is clearly seen in the stochastic dynamics. Our numerical results demonstrate that the multiple number of transduction channels per hair bundle is an important factor to the amplitude death phenomenon, because the phenomenon may disappear for a small number of transduction channels due to strong gating noise.

  16. Bundled slaty cleavage in laminated argillite, north-central minnesota

    USGS Publications Warehouse

    Southwick, D.L.

    1987-01-01

    Exceptional bundled slaty cleavage (defined herein) has been found in drill cores of laminated, folded, weakly metamorphosed argillite at several localities in the early Proterozoic Animikie basin of north-central Minnesota. The cleavage domains are more closely spaced within the cleavage bundles than outside them, the mean tectosilicate grain size of siltstone layers, measured normal to cleavage, is less in the cleavage bundles than outside them, and the cleavage bundles are enriched in opaque phases and phyllosilicates relative to extra-bundle segments. These facts suggest that pressure solution was a major factor in bundle development. If it is assumed that opaque phases have been conserved during pressure solution, the modal differences in composition between intra-bundle and extra-bundle segments of beds provide a means for estimating bulk material shortening normal to cleavage. Argillite samples from the central part of the Animikie basin have been shortened a minimum of about 22%, as estimated by this method. These estimates are similar to the shortening values derived from other strain markers in other rock types interbedded with the argillite, and are also consistent with the regional pattern of deformation. ?? 1987.

  17. Properties of microtubule bundles induced by Glyceraldehyde-3-phosphate dehydrogenase

    NASA Astrophysics Data System (ADS)

    Somers, Marijke; Engelborghs, Yves

    1991-05-01

    The binding of Glyceraldehyde-3-phosphate dehydrogenase (GAPDH; E.C. 1.2.1.12) to microtubules causes the microtubules to assemble into large bundles. This bundling can be considered as a further step in the assembly of supramolecular structures. The rate of bundle formation, after addition of GAPDH to preformed microtubules, is not dependent on the GAPDH concentration and reflects bundling kinetics. Bundle disassembly can be studied by the addition of 1 mM adenosine 5'-(β, -imidotri-phosphate) (AMPPNP) to bundled microtubules, and is extremely fast. Bundling reduces the rate of association of tubulin dimers to microtubules, as well as the dissocation from the microtubles. Both rates are reduced to the same extent. This is in agreement with the fact that the critical concentration of tubulin is practically not influenced by the binding of the enzyme. Adding microtubule associated proteins (at I=0.1 M) does not appreciably influence the affinity for GAPDH, but reduces bundle formation possibly for sterical reasons.

  18. Lexical Bundles: Facilitating University "Talk" in Group Discussions

    ERIC Educational Resources Information Center

    Heng, Chan Swee; Kashiha, Hadi; Tan, Helen

    2014-01-01

    Group discussion forms an integral language experience for most language learners, providing them with an opportunity to express themselves in a naturalistic setting. Multi-word expressions are commonly used and one of them is lexical bundles. Lexical bundles are types of extended collocations that occur more commonly than we expect; they are…

  19. His bundle pacing: Initial experience and lessons learned.

    PubMed

    Deshmukh, Amrish; Deshmukh, Pramod

    2016-01-01

    Direct His bundle pacing provides the most physiologic means of artificial pacing of the ventricles with a preserved His-Purkinje system and may play a role in patients with a diseased intrinsic conduction system. We describe our initial motivations and experience with permanent direct His bundle pacing and important lessons learned since that time. PMID:27591359

  20. 76 FR 61365 - Bundled Payments for Care Improvement Initiative

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... 25, 2011 we published a notice requesting applications in the Federal Register [76 FR 53137] to... HUMAN SERVICES Centers for Medicare & Medicaid Services Bundled Payments for Care Improvement Initiative.... SUMMARY: This notice extends the deadlines for the submission of the Bundled Payments for Care...

  1. A thermal-hydraulic code for transient analysis in a channel with a rod bundle

    SciTech Connect

    Khodjaev, I.D.

    1995-09-01

    The paper contains the model of transient vapor-liquid flow in a channel with a rod bundle of core of a nuclear power plant. The computer code has been developed to predict dryout and post-dryout heat transfer in rod bundles of nuclear reactor core under loss-of-coolant accidents. Economizer, bubble, dispersed-annular and dispersed regimes are taken into account. The computer code provides a three-field representation of two-phase flow in the dispersed-annular regime. Continuous vapor, continuous liquid film and entrained liquid drops are three fields. For the description of dispersed flow regime two-temperatures and single-velocity model is used. Relative droplet motion is taken into account for the droplet-to-vapor heat transfer. The conservation equations for each of regimes are solved using an effective numerical technique. This technique makes it possible to determine distribution of the parameters of flows along the perimeter of fuel elements. Comparison of the calculated results with the experimental data shows that the computer code adequately describes complex processes in a channel with a rod bundle during accident.

  2. Bundling of bovine and brine shrimp (Artemia) microtubules in vitro.

    PubMed

    MacRae, T H

    1984-06-01

    Cell-free extracts from embryos of the brine shrimp (Artemia) induced bundling of bovine microtubules assembled in the presence of glycerol and Mg++. Sedimentation of microtubules through sucrose cushions and subsequent electrophoresis revealed that bundling occurred independently of accessory proteins tightly bound to the microtubules. Bovine microtubules containing microtubule-associated proteins (MAPS) or assembled with taxol did not bundle. The unusual polymerization properties of homogeneous Artemia tubulin, bundling in the absence of added factors and the small number of microtubules assembled in crude embryo extracts upon addition of taxol precluded a complete comparative study of Artemia and bovine microtubule bundling. Interesting properties of the in vitro assembly of Artemia microtubules were, however, elaborated and putative Artemia MAPs were observed as a consequence of the work with brine shrimp embryos. PMID:6744423

  3. Assembly of hair bundles, an amazing problem for cell biology.

    PubMed

    Barr-Gillespie, Peter-G

    2015-08-01

    The hair bundle--the sensory organelle of inner-ear hair cells of vertebrates--exemplifies the ability of a cell to assemble complex, elegant structures. Proper construction of the bundle is required for proper mechanotransduction in response to external forces and to transmit information about sound and movement. Bundles contain tightly controlled numbers of actin-filled stereocilia, which are arranged in defined rows of precise heights. Indeed, many deafness mutations that disable hair-cell cytoskeletal proteins also disrupt bundles. Bundle assembly is a tractable problem in molecular and cellular systems biology; the sequence of structural changes in stereocilia is known, and a modest number of proteins may be involved. PMID:26229154

  4. Voltage- and calcium-dependent motility of saccular hair bundles

    NASA Astrophysics Data System (ADS)

    Quiñones, Patricia M.; Meenderink, Sebastiaan W. F.; Bozovic, Dolores

    2015-12-01

    Active bundle motility, which is hypothesized to supply feedback for mechanical amplification of signals, is thought to enhance sensitivity and sharpen tuning in vestibular and auditory organs. To study active hair bundle motility, we combined high-speed camera recordings of bullfrog sacculi, which were mounted in a two-compartment chamber, and voltage-clamp of the hair cell membrane potential. Using this paradigm, we measured three types of bundle motions: 1) spontaneous oscillations which can be analyzed to measure the physiological operating range of the transduction channel; 2) a sustained quasi-static movement of the bundle that depends on membrane potential; and 3) a fast, transient and asymmetric movement that resets the bundle position and depends on changes in the membrane potential. These data support a role for both calcium and voltage in the transduction-channel function.

  5. Genetic algorithm for bundle adjustment in aerial panoramic stitching

    NASA Astrophysics Data System (ADS)

    Zhang, Chunxiao; Wen, Gaojin; Wu, Chunnan; Wang, Hongmin; Shang, Zhiming; Zhang, Qian

    2015-03-01

    This paper presents a genetic algorithm for bundle adjustment in aerial panoramic stitching. Compared with the conventional LM (Levenberg-Marquardt) algorithm for bundle adjustment, the proposed bundle adjustment combining the genetic algorithm optimization eliminates the possibility of sticking into the local minimum, and not requires the initial estimation of desired parameters, naturally avoiding the associated steps, that includes the normalization of matches, the computation of homography transformation, the calculations of rotation transformation and the focal length. Since the proposed bundle adjustment is composed of the directional vectors of matches, taking the advantages of genetic algorithm (GA), the Jacobian matrix and the normalization of residual error are not involved in the searching process. The experiment verifies that the proposed bundle adjustment based on the genetic algorithm can yield the global solution even in the unstable aerial imaging condition.

  6. Vision, healing brush, and fiber bundles

    NASA Astrophysics Data System (ADS)

    Georgiev, Todor

    2005-03-01

    The Healing Brush is a tool introduced for the first time in Adobe Photoshop (2002) that removes defects in images by seamless cloning (gradient domain fusion). The Healing Brush algorithms are built on a new mathematical approach that uses Fibre Bundles and Connections to model the representation of images in the visual system. Our mathematical results are derived from first principles of human vision, related to adaptation transforms of von Kries type and Retinex theory. In this paper we present the new result of Healing in arbitrary color space. In addition to supporting image repair and seamless cloning, our approach also produces the exact solution to the problem of high dynamic range compression of17 and can be applied to other image processing algorithms.

  7. Extendability of parallel sections in vector bundles

    NASA Astrophysics Data System (ADS)

    Kirschner, Tim

    2016-01-01

    I address the following question: Given a differentiable manifold M, what are the open subsets U of M such that, for all vector bundles E over M and all linear connections ∇ on E, any ∇-parallel section in E defined on U extends to a ∇-parallel section in E defined on M? For simply connected manifolds M (among others) I describe the entirety of all such sets U which are, in addition, the complement of a C1 submanifold, boundary allowed, of M. This delivers a partial positive answer to a problem posed by Antonio J. Di Scala and Gianni Manno (2014). Furthermore, in case M is an open submanifold of Rn, n ≥ 2, I prove that the complement of U in M, not required to be a submanifold now, can have arbitrarily large n-dimensional Lebesgue measure.

  8. Geometries and applications of active fiber bundles

    NASA Astrophysics Data System (ADS)

    Giglmayr, Josef

    2001-10-01

    Active fiber bundles (FBs) are aimed to model photonic switching and processing in 3-D without the restrictions of the photonic technology. The 2-D photonic architectures are assumed to be implemented by networks of directional couplers (DCs) and Mach-Zehnder interferometers (MZIs), respectively. For the implementation several crucial problems are expected: (1) proper operation of the spatial couplers/switches (nonblocking interconnections) and (2) coupling in the interstage interconnection section mainly caused by parallel and crossing fibers/waveguides (WGs). For the design of proper operating switches (refinement of couplers) the application of decoupling concepts of modern control theory is proposed. The final goal is to translate the refined couplers into integrated photonic architectures rather than into additional lightwave circuits (LWCs) which simply would increase the coupling. The decoupling concepts are reviewed. The paper is an attempt to prepare for applying well-known system engineering concepts to the upcoming technology of photonics.

  9. Advanced tube-bundle rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Kazaroff, John M.; Pavli, Albert J.

    1990-01-01

    An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

  10. Emitters of N-photon bundles

    PubMed Central

    Muñoz, C. Sánchez; del Valle, E.; Tudela, A. González; Müller, K.; Lichtmannecker, S.; Kaniber, M.; Tejedor, C.; Finley, J.J.; Laussy, F.P.

    2014-01-01

    Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or “bundles” of N photons, for integer N. Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state of the art samples. The emission can be tuned with system parameters so that the device behaves as a laser or as a N-photon gun. The theoretical formalism to characterize such emitters is developed, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications. PMID:25013456

  11. Fiber bundle model under fluid pressure

    NASA Astrophysics Data System (ADS)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting.

  12. Fiber bundle model under fluid pressure.

    PubMed

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting. PMID:27078437

  13. Historical dynamics in ecosystem service bundles

    PubMed Central

    Renard, Delphine; Rhemtulla, Jeanine M.; Bennett, Elena M.

    2015-01-01

    Managing multiple ecosystem services (ES), including addressing trade-offs between services and preventing ecological surprises, is among the most pressing areas for sustainability research. These challenges require ES research to go beyond the currently common approach of snapshot studies limited to one or two services at a single point in time. We used a spatiotemporal approach to examine changes in nine ES and their relationships from 1971 to 2006 across 131 municipalities in a mixed-use landscape in Quebec, Canada. We show how an approach that incorporates time and space can improve our understanding of ES dynamics. We found an increase in the provision of most services through time; however, provision of ES was not uniformly enhanced at all locations. Instead, each municipality specialized in providing a bundle (set of positively correlated ES) dominated by just a few services. The trajectory of bundle formation was related to changes in agricultural policy and global trends; local biophysical and socioeconomic characteristics explained the bundles’ increasing spatial clustering. Relationships between services varied through time, with some provisioning and cultural services shifting from a trade-off or no relationship in 1971 to an apparent synergistic relationship by 2006. By implementing a spatiotemporal perspective on multiple services, we provide clear evidence of the dynamic nature of ES interactions and contribute to identifying processes and drivers behind these changing relationships. Our study raises questions about using snapshots of ES provision at a single point in time to build our understanding of ES relationships in complex and dynamic social-ecological systems. PMID:26460005

  14. His bundle recordings in right bundle-branch block coexisting with iatrogenic right ventricular pre-excitation

    PubMed Central

    Castellanos, Agustin; Castillo, Cesar A.

    1972-01-01

    Iatrogenic right ventricular pre-excitation failed to abolish right bundle-branch block in two patients. When `exclusive' His bundle pacing was performed, the QRS complexes, St-V, and St-LVE intervals were similar to the ventricular deflections, H-V, and V-LVE (intervals) recorded during sinus rhythm. `Exclusive' pacing of the ordinary muscle at the right ventricular inflow tract produced a complete left bundle-branch block pattern without abnormal left axis deviation. Pacing of both His bundle and ordinary muscle yielded combination complexes in which the right bundle-branch block pattern persisted. The ventricular activation process was studied in these beats, as well as during the right and left bundle-branch block induced by coupled atrial stimulation. It appeared as if certain areas of the right septal surface behaved, electrophysiologically, as if they belonged to the left ventricle. Impulses emerging from these sites were not propagated to the right ventricular free wall. The latter was activated by the excitation front emerging through the left bundle system. During right bundle-branch block the endocardium of the right ventricular inflow was activated before the peak of the R in V1. Bipolar leads, 1 mm apart (with the possible exception of the ones over the tricuspid valve), were helpful in mapping the spread of activation in the human heart. Images PMID:18610233

  15. DESIGN OF WIRE-WRAPPED ROD BUNDLE MATCHED INDEX-OF-REFRACTION EXPERIMENTS

    SciTech Connect

    Hugh McIlroy; Hongbin Zhang; Kurt Hamman

    2008-05-01

    Experiments will be conducted in the Idaho National Laboratory (INL) Matched Index-of-Refraction (MIR) Flow Facility [1] to characterize the three-dimensional velocity and turbulence fields in a wire-wrapped rod bundle typically employed in liquid-metal cooled fast reactors and to provide benchmark data for computer code validation. Sodium cooled fast reactors are under consideration for use in the U.S. Department of Energy (DOE) Global Nuclear Energy Partnership (GNEP) program. The experiment model will be constructed of quartz components and the working fluid will be mineral oil. Accurate temperature control (to within 0.05 oC) matches the index-of-refraction of mineral oil with that of quartz and renders the model transparent to the wavelength of laser light employed for optical measurements. The model will be a scaled 7-pin rod bundle enclosed in a hexagonal canister. Flow field measurements will be obtained with a LaVision 3-D particle image velocimeter (PIV) and complimented by near-wall velocity measurements obtained from a 2-D laser Doppler velocimeter (LDV). These measurements will be used as benchmark data for computational fluid dynamics (CFD) validation. The rod bundle model dimensions will be scaled up from the typical dimensions of a fast reactor fuel assembly to provide the maximum Reynolds number achievable in the MIR flow loop. A range of flows from laminar to fully-turbulent will be available with a maximum Reynolds number, based on bundle hydraulic diameter, of approximately 22,000. The fuel pins will be simulated by 85 mm diameter quartz tubes (closed on the inlet ends) and the wire-wrap will be simulated by 25 mm diameter quartz rods. The canister walls will be constructed from quartz plates. The model will be approximately 2.13 m in length. Bundle pressure losses will also be measured and the data recorded for code comparisons. The experiment design and preliminary CFD calculations, which will be used to provide qualitative hydrodynamic

  16. Optical fuel pin scanner. [Patent application; for reading identifications

    DOEpatents

    Kirchner, T.L.; Powers, H.G.

    1980-12-09

    This patent relates to an optical identification system developed for post-irradiation disassembly and analysis of fuel bundle assemblies. The apparatus is designed to be lowered onto a stationary fuel pin to read identification numbers or letters imprinted on the circumference of the top fuel pin and cap. (DLC)

  17. Effectiveness of Hair Bundle Motility as the Cochlear Amplifier

    PubMed Central

    Sul, Bora; Iwasa, Kuni H.

    2009-01-01

    Abstract The effectiveness of hair bundle motility in mammalian and avian ears is studied by examining energy balance for a small sinusoidal displacement of the hair bundle. The condition that the energy generated by a hair bundle must be greater than energy loss due to the shear in the subtectorial gap per hair bundle leads to a limiting frequency that can be supported by hair-bundle motility. Limiting frequencies are obtained for two motile mechanisms for fast adaptation, the channel re-closure model and a model that assumes that fast adaptation is an interplay between gating of the channel and the myosin motor. The limiting frequency obtained for each of these models is an increasing function of a factor that is determined by the morphology of hair bundles and the cochlea. Primarily due to the higher density of hair cells in the avian inner ear, this factor is ∼10-fold greater for the avian ear than the mammalian ear, which has much higher auditory frequency limit. This result is consistent with a much greater significance of hair bundle motility in the avian ear than that in the mammalian ear. PMID:19917218

  18. Mechanical Amplification Exhibited by Quiescent Saccular Hair Bundles

    PubMed Central

    Roongthumskul, Yuttana; Bozovic, Dolores

    2015-01-01

    Spontaneous oscillations exhibited by free-standing hair bundles from the Bullfrog sacculus suggest the existence of an active process that might underlie the exquisite sensitivity of the sacculus to mechanical stimulation. However, this spontaneous activity is suppressed by coupling to an overlying membrane, which applies a large mechanical load on the bundle. How a quiescent hair bundle utilizes its active process is still unknown. We studied the dynamics of motion of individual hair bundles under different offsets in the bundle position, and observed the occurrence of spikes in hair-bundle motion, associated with the generation of active work. These mechanical spikes can be evoked by a sinusoidal stimulus, leading to an amplified movement of the bundle with respect to the passive response. Amplitude gain reached as high as 100-fold at small stimulus amplitudes. Amplification of motion decreased with increasing amplitude of stimulation, ceasing at ∼6–12 pN stimuli. Results from numerical simulations suggest that the adaptation process, mediated by myosin 1c, is not required for the production of mechanical spikes. PMID:25564852

  19. Spontaneous Oscillation by Hair Bundles of the Bullfrog's Sacculus

    PubMed Central

    Martin, Pascal; Bozovic, D.; Choe, Y.; Hudspeth, A. J.

    2007-01-01

    One prominent manifestation of mechanical activity in hair cells is spontaneous otoacoustic emission, the unprovoked emanation of sound by an internal ear. Because active hair-bundle motility probably constitutes the active process of non-mammalian hair cells, we investigated the ability of hair bundles in the bullfrog's sacculus to produce oscillations that might underlie spontaneous otoacoustic emissions. When maintained in the ear's normal ionic milieu, many bundles oscillated spontaneously through distances as great as 80 nm at frequencies of 5-50 Hz. Whole-cell recording disclosed that the positive phase of movement was associated with the opening of transduction channels. Gentamicin, which blocks transduction channels, reversibly arrested oscillation; drugs that affect the cAMP phosphorylation pathway and might influence myosin's activity altered the rate of oscillation. Increasing the Ca2+ concentration rendered oscillations faster and smaller until they were suppressed; lowering the Ca2+ concentration moderately with chelators had the opposite effect. When a bundle was offset with a stimulus fiber, oscillations were transiently suppressed but gradually resumed. Loading a bundle by partial displacement clamping, which simulated the presence of the accessory structures to which a bundle is ordinarily attached, increased the frequency and diminished the magnitude of oscillation. These observations accord with a model in which oscillations arise from the interplay of the hair bundle's negative stiffness with the activity of adaptation motors and with Ca2+-dependent relaxation of gating springs. PMID:12805294

  20. Mechanical amplification exhibited by quiescent saccular hair bundles.

    PubMed

    Roongthumskul, Yuttana; Bozovic, Dolores

    2015-01-01

    Spontaneous oscillations exhibited by free-standing hair bundles from the Bullfrog sacculus suggest the existence of an active process that might underlie the exquisite sensitivity of the sacculus to mechanical stimulation. However, this spontaneous activity is suppressed by coupling to an overlying membrane, which applies a large mechanical load on the bundle. How a quiescent hair bundle utilizes its active process is still unknown. We studied the dynamics of motion of individual hair bundles under different offsets in the bundle position, and observed the occurrence of spikes in hair-bundle motion, associated with the generation of active work. These mechanical spikes can be evoked by a sinusoidal stimulus, leading to an amplified movement of the bundle with respect to the passive response. Amplitude gain reached as high as 100-fold at small stimulus amplitudes. Amplification of motion decreased with increasing amplitude of stimulation, ceasing at ∼6-12 pN stimuli. Results from numerical simulations suggest that the adaptation process, mediated by myosin 1c, is not required for the production of mechanical spikes. PMID:25564852

  1. Spontaneous oscillation by hair bundles of the bullfrog's sacculus.

    PubMed

    Martin, Pascal; Bozovic, D; Choe, Y; Hudspeth, A J

    2003-06-01

    One prominent manifestation of mechanical activity in hair cells is spontaneous otoacoustic emission, the unprovoked emanation of sound by an internal ear. Because active hair bundle motility probably constitutes the active process of nonmammalian hair cells, we investigated the ability of hair bundles in the bullfrog's sacculus to produce oscillations that might underlie spontaneous otoacoustic emissions. When maintained in the normal ionic milieu of the ear, many bundles oscillated spontaneously through distances as great as 80 nm at frequencies of 5-50 Hz. Whole-cell recording disclosed that the positive phase of movement was associated with the opening of transduction channels. Gentamicin, which blocks transduction channels, reversibly arrested oscillation; drugs that affect the cAMP phosphorylation pathway and might influence the activity of myosin altered the rate of oscillation. Increasing the Ca 2+ concentration rendered oscillations faster and smaller until they were suppressed; lowering the Ca 2+ concentration moderately with chelators had the opposite effect. When a bundle was offset with a stimulus fiber, oscillations were transiently suppressed but gradually resumed. Loading a bundle by partial displacement clamping, which simulated the presence of the accessory structures to which a bundle is ordinarily attached, increased the frequency and diminished the magnitude of oscillation. These observations accord with a model in which oscillations arise from the interplay of the hair bundle's negative stiffness with the activity of adaptation motors and with Ca 2+-dependent relaxation of gating springs. PMID:12805294

  2. Equivariant algebraic vector bundles over representations of reductive groups: theory.

    PubMed Central

    Masuda, M; Petrie, T

    1991-01-01

    Let G be a reductive algebraic group and let B be an affine variety with an algebraic action of G. Everything is defined over the field C of complex numbers. Consider the trivial G-vector bundle B x S = S over B where S is a G-module. From the endomorphism ring R of the G-vector bundle S a construction of G-vector bundles over B is given. The bundles constructed this way have the property that when added to S they are isomorphic to F + S for a fixed G-module F. For such a bundle E an invariant rho(E) is defined that lies in a quotient of R. This invariant allows us to distinguish nonisomorphic G-vector bundles. This is applied to the case where B is a G-module and, in that case, an invariant of the underlying equivariant variety is given too. These constructions and invariants are used to produce families of inequivalent G-vector bundles over G-modules and families of inequivalent G actions on affine spaces for some finite and some connected semisimple groups. PMID:11607220

  3. Stochastic Molecular Transport on Microtubule Bundles with Structural Defects

    NASA Astrophysics Data System (ADS)

    Gramlich, M. W.; Tabei, S. M. Ali

    Intracellular transport involves complex coordination of multiple components such as: the cytoskeletal network and molecular motors. Perturbations in this process can amplify over time and space, thereby affecting transport. One little studied component of transport are structural defects in the cytoskeletal network. In this talk we will present a stochastic model of the interaction of the molecular motor, kinesin-1, and a bundled cystoskeletal network of microtubules, and explicitly explore the role of microtubule ends (a type of defect) on long-range transport. We will show how different types of end distributions can ultimately result in the same observed transport behavior for bundles. We compare transport on completely uniform bundles, found in the axon, to completely random bundles, found in dendrites. Because of the un-biased random bundle nature, defects affect transport on dendrite bundles more than on uniform bundles in the axon. Further, defects act as large spatial-scale traps that result in random wait-times which have been assumed in previous models.

  4. Measurement of depletion-induced force in microtubule bundles

    NASA Astrophysics Data System (ADS)

    Hilitski, Fiodar; Ward, Andrew; Dogic, Zvonimir

    2014-03-01

    Microtubule (MT) bundles formed in the presence of non-adsorbing polymers - poly-ethylene glycol (PEG) or Dextran - are widely used in experimental active matter systems. However, many properties of such MT bundles have not been studied experimentally. In this work, we combine optical trapping techniques with an umbrella sampling method in order to measure the depletion force acting on individual microtubule in the axial direction within the bundle. We find depletion force is independent of bundle overlap length and measure its magnitude to be on the order of tens of kB/T μm. We explore the dependence of the depletion force on concentration of depletant (PEG 20K) as well as K+ ions (necessary for screening electrostatic repulsion between MT filaments). We also verify additivity of depletion interaction and confirm that force is increased by a factor of two for three-MT bundles. Additionally, our experimental technique allows us to probe interactions between MTs within the bundle. Experimental data suggests that filaments in the bundle interact only hydrodynamically when depletant concentrations are low enough; however, we observe onset of solid-like friction when osmotic pressure is increased above a certain threshold.

  5. Steric Effects Induce Geometric Remodeling of Actin Bundles in Filopodia.

    PubMed

    Dobramysl, Ulrich; Papoian, Garegin A; Erban, Radek

    2016-05-10

    Filopodia are ubiquitous fingerlike protrusions, spawned by many eukaryotic cells, to probe and interact with their environments. Polymerization dynamics of actin filaments, comprising the structural core of filopodia, largely determine their instantaneous lengths and overall lifetimes. The polymerization reactions at the filopodial tip require transport of G-actin, which enter the filopodial tube from the filopodial base and diffuse toward the filament barbed ends near the tip. Actin filaments are mechanically coupled into a tight bundle by cross-linker proteins. Interestingly, many of these proteins are relatively short, restricting the free diffusion of cytosolic G-actin throughout the bundle and, in particular, its penetration into the bundle core. To investigate the effect of steric restrictions on G-actin diffusion by the porous structure of filopodial actin filament bundle, we used a particle-based stochastic simulation approach. We discovered that excluded volume interactions result in partial and then full collapse of central filaments in the bundle, leading to a hollowed-out structure. The latter may further collapse radially due to the activity of cross-linking proteins, hence producing conical-shaped filament bundles. Interestingly, electron microscopy experiments on mature filopodia indeed frequently reveal actin bundles that are narrow at the tip and wider at the base. Overall, our work demonstrates that excluded volume effects in the context of reaction-diffusion processes in porous networks may lead to unexpected geometric growth patterns and complicated, history-dependent dynamics of intermediate metastable configurations. PMID:27166814

  6. Bundling actin filaments from membranes: some novel players

    PubMed Central

    Thomas, Clément

    2012-01-01

    Progress in live-cell imaging of the cytoskeleton has significantly extended our knowledge about the organization and dynamics of actin filaments near the plasma membrane of plant cells. Noticeably, two populations of filamentous structures can be distinguished. On the one hand, fine actin filaments which exhibit an extremely dynamic behavior basically characterized by fast polymerization and prolific severing events, a process referred to as actin stochastic dynamics. On the other hand, thick actin bundles which are composed of several filaments and which are comparatively more stable although they constantly remodel as well. There is evidence that the actin cytoskeleton plays critical roles in trafficking and signaling at both the cell cortex and organelle periphery but the exact contribution of actin bundles remains unclear. A common view is that actin bundles provide the long-distance tracks used by myosin motors to deliver their cargo to growing regions and accordingly play a particularly important role in cell polarization. However, several studies support that actin bundles are more than simple passive highways and display multiple and dynamic roles in the regulation of many processes, such as cell elongation, polar auxin transport, stomatal and chloroplast movement, and defense against pathogens. The list of identified plant actin-bundling proteins is ever expanding, supporting that plant cells shape structurally and functionally different actin bundles. Here I review the most recently characterized actin-bundling proteins, with a particular focus on those potentially relevant to membrane trafficking and/or signaling. PMID:22936939

  7. Two-state approach to stochastic hair bundle dynamics

    NASA Astrophysics Data System (ADS)

    Clausznitzer, Diana; Lindner, Benjamin; Jülicher, Frank; Martin, Pascal

    2008-04-01

    Hair cells perform the mechanoelectrical transduction of sound signals in the auditory and vestibular systems of vertebrates. The part of the hair cell essential for this transduction is the so-called hair bundle. In vitro experiments on hair cells from the sacculus of the American bullfrog have shown that the hair bundle comprises active elements capable of producing periodic deflections like a relaxation oscillator. Recently, a continuous nonlinear stochastic model of the hair bundle motion [Nadrowski , Proc. Natl. Acad. Sci. U.S.A. 101, 12195 (2004)] has been shown to reproduce the experimental data in stochastic simulations faithfully. Here, we demonstrate that a binary filtering of the hair bundle's deflection (experimental data and continuous hair bundle model) does not change significantly the spectral statistics of the spontaneous as well as the periodically driven hair bundle motion. We map the continuous hair bundle model to the FitzHugh-Nagumo model of neural excitability and discuss the bifurcations between different regimes of the system in terms of the latter model. Linearizing the nullclines and assuming perfect time-scale separation between the variables we can map the FitzHugh-Nagumo system to a simple two-state model in which each of the states corresponds to the two possible values of the binary-filtered hair bundle trajectory. For the two-state model, analytical expressions for the power spectrum and the susceptibility can be calculated [Lindner and Schimansky-Geier, Phys. Rev. E 61, 6103 (2000)] and show the same features as seen in the experimental data as well as in simulations of the continuous hair bundle model.

  8. Examination of Zircaloy-clad spent fuel after extended pool storage

    SciTech Connect

    Bradley, E.R.; Bailey, W.J.; Johnson, A.B. Jr.; Lowry, L.M.

    1981-09-01

    This report presents the results from metallurgical examinations of Zircaloy-clad fuel rods from two bundles (0551 and 0074) of Shippingport PWR Core 1 blanket fuel after extended water storage. Both bundles were exposed to water in the reactor from late 1957 until discharge. The estimated average burnups were 346 GJ/kgU (4000 MWd/MTU) for bundle 0551 and 1550 GJ/kgU (18,000 MWd/MTU) for bundle 0074. Fuel rods from bundle 0551 were stored in deionized water for nearly 21 yr prior to examination in 1980, representing the world's oldest pool-stored Zircaloy-clad fuel. Bundle 0074 has been stored in deionized water since reactor discharge in 1964. Data from the current metallurgical examinations enable a direct assessment of extended pool storage effects because the metallurgical condition of similar fuel rods was investigated and documented soon after reactor discharge. Data from current and past examinations were compared, and no significant degradation of the Zircaloy cladding was indicated after almost 21 yr in water storage. The cladding dimensions and mechanical properties, fission gas release, hydrogen contents of the cladding, and external oxide film thicknesses that were measured during the current examinations were all within the range of measurements made on fuel bundles soon after reactor discharge. The appearance of the external surfaces and the microstructures of the fuel and cladding were also similar to those reported previously. In addition, no evidence of accelerated corrosion or hydride redistribution in the cladding was observed.

  9. Modifications of bundles, elliptic integrable systems, and related problems

    NASA Astrophysics Data System (ADS)

    Zotov, A. V.; Smirnov, A. V.

    2013-10-01

    We describe a construction of elliptic integrable systems based on bundles with nontrivial characteristic classes, especially attending to the bundle-modification procedure, which relates models corresponding to different characteristic classes. We discuss applications and related problems such as the Knizhnik-Zamolodchikov-Bernard equations, classical and quantum R-matrices, monopoles, spectral duality, Painlevé equations, and the classical-quantum correspondence. For an SL(N,ℂ)-bundle on an elliptic curve with nontrivial characteristic classes, we obtain equations of isomonodromy deformations.

  10. Structural Transitions of F-Actin:Espin Bundles

    NASA Astrophysics Data System (ADS)

    Purdy, Kirstin; Bartles, James; Wong, Gerard

    2006-03-01

    Espin is an actin bundling protein involved in the formation of the parallel bundles of filamentous actin in hair cell stereocilia. Mutations in espin are implicated in deafness phenotypes in mice and humans. We present measurements of the F-actin structures induced by wild type and by mutated espin obtained via small angle x-ray scattering and fluorescence microscopy. We found that wild type espin induced a paracrystalline hexagonal array of twisted F-actin, whereas the mutated espin only condensed the F-actin into a nematic-like phase. The possibility of coexisting nematic and bundled actin in mixtures containing both mutant and wild type espins was also investigated.

  11. Code System for Spent Fuel Heating Analysis.

    Energy Science and Technology Software Center (ESTSC)

    1999-05-24

    Version 00 SFHA calculates steady-state fuel rod temperatures for hexagon and square-fuel bundles. The code is used to perform sensitivity studies and confirmatory analyses of results submitted by applicants for spent fuel storage licenses. All three modes of heat transfer are considered; radiation, convection, and conduction. Each is modeled separately. SFHA benchmark calculations were made with test data to validate the use of a simple one-dimensional heat transfer model for estimating fuel rod temperatures. Benchmarkmore » results show that SFHA is capable of calculating spent fuel rod temperatures for square and hexagonal fuel bundles under various environments for the consolidated or unconsolidated condition. The program is menu-driven and executes automatically after all required information is entered.« less

  12. Fuel or irradiation subassembly

    DOEpatents

    Seim, O.S.; Hutter, E.

    1975-12-23

    A subassembly for use in a nuclear reactor is described which incorporates a loose bundle of fuel or irradiation pins enclosed within an inner tube which in turn is enclosed within an outer coolant tube and includes a locking comb consisting of a head extending through one side of the inner sleeve and a plurality of teeth which extend through the other side of the inner sleeve while engaging annular undercut portions in the bottom portion of the fuel or irradiation pins to prevent movement of the pins.

  13. Concise Care Bundles In Acute Medicine

    PubMed Central

    Kivlin, Jude; Altemimi, Harith

    2015-01-01

    The Queen Elizabeth Hospital in King's Lynn, Norfolk is a 488 bed hospital providing services to approximately 331,000 people across 750 square miles. In 2012 a need was recognised for documentation (pathways) in a practical format to increase usage of national guidelines and facilitate adherence to best practice (gold standards of care) that could be easily version controlled, auditable and provide support in clinical decision-making by junior doctors. BMJ Action Sets[1] fulfilled the brief with expert knowledge, version control and support, though they were deemed too lengthy and unworkable in fast paced settings like the medical assessment unit; they formed the base creation of concise care bundles (CCB). CCB were introduced for 21 clinical presentations and one procedure. Outcomes were fully audited and showed significant improvement in a range of measures, including an increase in completions of CHADVASC score in atrial fibrillation, antibiotics prescribed per protocol in chronic obstructive pulmonary disease (COPD), and Blatchford score recorded for patients presenting with upper gastrointestinal bleed. PMID:26734437

  14. WEAVE MOS fibre bundle test plan

    NASA Astrophysics Data System (ADS)

    Sayède, Frédéric; Guinouard, Isabelle; Fasola, Gilles; Lhome, Emilie; Amans, Jean-Philippe; Bonifacio, Piercarlo; Abrams, Don Carlos; Middleton, Kevin; Dalton, Gavin; Aguerri, J. Alfonso L.; Trager, Scott C.; Loeb, Avi

    2014-07-01

    WEAVE is the next-generation wide-field optical spectroscopy facility for the William Herschel Telescope (WHT) in La Palma, Canary Islands, Spain. WEAVE mainly aims at spectroscopic follow-up of ground-based (e.g. LOFAR) and space-based (GAIA) surveys. The facility consists of a new 2-degree field-of-view prime focus corrector with a 1000- multiplex fibre positioner, a small number of individually deployable integral field units, and a large single integral field unit. The IFUs (Integral Field Units) and the MOS fibres can be used to feed a dual-beam spectrograph that will provide full coverage of the majority of the visible spectrum in a single exposure at a spectral resolution of ~5000 or modest wavelength coverage in both arms at a resolution ~20000. The instrument is expected to be on-sky by 2017 to provide spectroscopic sampling of the fainter end of the Gaia astrometric catalogue, chemical labeling of stars to V~17, and dedicated follow up of substantial numbers of sources from the medium deep LOFAR surveys. After a brief description of the MOS fibre bundle, we described the proposed test plan and the test bench of the 2x1000 WEAVE MOS fibres. The test bench allows us to evaluate the Focal Ratio Degradation and the throughput of the fibers fitted with their buttons and slitlets.

  15. Microendoscopic holography with flexible fiber bundle

    NASA Astrophysics Data System (ADS)

    Coquoz, Olivier; Depeursinge, Christian D.; Conde, Ramiro; de Haller, Emmanuel B.

    1994-05-01

    An in situ holographic technique, involving the use of a flexible miniaturized endoscope (diameter less than 1 mm) coupled to a CCD camera, to record the hologram, has been developed for medical applications. The hologram is formed, by reflection, on the tip of a multimode fiber bundle (MMB), sampled, and then treated electronically. The image is reconstructed numerically, providing more flexibility to the holographic process. Reconstructed images show the capability of the microendoscopic system to restore 3D informations of the observed scene. The limitations of the holographic approach with the microendoscope have been evaluated and discussed in terms of the resolution limit. In particular, the low frequency sampling of the hologram through the MMB is not a limiting factor for the range of observation distance investigated (4 - 10 mm). A good accordance between the experimental results and the theoretical predictions was found by comparing the cut-off frequency obtained. Our results show that, for the considered observation distances, objects of a few micrometers can be clearly identified. The different sources of noise are analyzed and their influence on the quality of the reconstructed image have been quantified.

  16. Heat transfer to water from a vertical tube bundle under natural-circulation conditions. [PWR; BWR

    SciTech Connect

    Gruszczynski, M.J.; Viskanta, R.

    1983-01-01

    The natural circulation heat transfer data for longitudinal flow of water outside a vertical rod bundle are needed for developing correlations which can be used in best estimate computer codes to model thermal-hydraulic behavior of nuclear reactor cores under accident or shutdown conditions. The heat transfer coefficient between the fuel rod surface and the coolant is the key parameter required to predict the fuel temperature. Because of the absence of the required heat transfer coefficient data base under natural circulation conditions, experiments have been performed in a natural circulation loop. A seven-tube bundle having a pitch-to-diameter ratio of 1.25 was used as a test heat exchanger. A circulating flow was established in the loop, because of buoyancy differences between its two vertical legs. Steady-state and transient heat transfer measurements have been made over as wide a range of thermal conditions as possible with the system. Steady state heat transfer data were correlated in terms of relevant dimensionless parameters. Empirical correlations for the average Nusselt number, in terms of Reynolds number, Rayleigh number and the ratio of Grashof to Reynolds number are given.

  17. Stability analysis of a square rod bundle sub-channel in supercritical water reactor

    NASA Astrophysics Data System (ADS)

    Hai-jun, Wang; Ting, You; Lei, Zhang; Hong-fang, Gu; Yu-shan, Luo; Ji-lian, Bian

    2013-07-01

    Extensive investigations on the flow and heat transfer behavior in SCWR fuel assembly have been undertaken worldwide. However, stability analysis of supercritical water in the sub-channels of tight lattices is still lacking. In this paper, the flow stability of a fuel bundle channel with square pitches has been analyzed using commercial CFD code-ANSYS Fluent. Typical dynamic instability of Density Wave Oscillation (DWO) has occurred in heated channel containing fluids at supercritical pressure. A further discussion about the impacts of various operational parameters (e.g. power input, system pressure, mass velocity, inlet temperature, etc) shows that the system becomes more stable as system pressure and/or mass flow rate increases. An increase in inlet temperature also has a stabilizing effect on the system.

  18. 15. VIEW OF SHINGLES BUNDLED, PLACED ON PALLET, AND READIED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW OF SHINGLES BUNDLED, PLACED ON PALLET, AND READIED FOR FORKLIFT OPERATOR TO MOVE PALLET OF SHINGLES TO LOADING DOCK - Lester Shingle Mill, 1602 North Eighteenth Street, Sweet Home, Linn County, OR

  19. Mechanical Models of Microtubule Bundle Collapse in Alzheimer's Disease

    NASA Astrophysics Data System (ADS)

    Sendek, Austin; Singh, Rajiv; Cox, Daniel

    2013-03-01

    Amyloid-beta aggregates initiate Alzheimer's disease, and downstream trigger degradation of tau proteins that act as microtubule bundle stabilizers and mechanical spacers. Currently it is unclear which of tau cutting by proteases, tau phosphorylation, or tau aggregation are responsible for cytoskeleton degradation., We construct a percolation simulation of the microtubule bundle using a molecular spring model for the taus and including depletion force attraction between microtubules and membrane/actin cytoskeletal surface tension. The simulation uses a fictive molecular dynamics to model the motion of the individual microtubules within the bundle as a result of random tau removal, and calculates the elastic modulus of the bundle as the tau concentration falls. We link the tau removal steps to kinetic tau steps in various models of tau degradation. Supported by US NSF Grant DMR 1207624

  20. Heat transfer characteristics of tube bundles during boiling in vacuum

    NASA Astrophysics Data System (ADS)

    Slesarenko, V. N.; Zakharov, G. A.

    1992-06-01

    Heat transfer during boiling in vacuum was compared experimentally for single tubes, rows of tube, and tube bundles to analyze characteristic properties of vaporization under such conditions. Relations for calculating heat transfer coefficients are proposed.

  1. Bundles of Norms About Teen Sex and Pregnancy.

    PubMed

    Mollborn, Stefanie; Sennott, Christie

    2015-09-01

    Teen pregnancy is a cultural battleground in struggles over morality, education, and family. At its heart are norms about teen sex, contraception, pregnancy, and abortion. Analyzing 57 interviews with college students, we found that "bundles" of related norms shaped the messages teens hear. Teens did not think their communities encouraged teen sex or pregnancy, but normative messages differed greatly, with either moral or practical rationalizations. Teens readily identified multiple norms intended to regulate teen sex, contraception, abortion, childbearing, and the sanctioning of teen parents. Beyond influencing teens' behavior, norms shaped teenagers' public portrayals and post hoc justifications of their behavior. Although norm bundles are complex to measure, participants could summarize them succinctly. These bundles and their conflicting behavioral prescriptions create space for human agency in negotiating normative pressures. The norm bundles concept has implications for teen pregnancy prevention policies and can help revitalize social norms for understanding health behaviors. PMID:25387911

  2. Assembly of hair bundles, an amazing problem for cell biology

    PubMed Central

    Barr-Gillespie, Peter-G.

    2015-01-01

    The hair bundle—the sensory organelle of inner-ear hair cells of vertebrates—exemplifies the ability of a cell to assemble complex, elegant structures. Proper construction of the bundle is required for proper mechanotransduction in response to external forces and to transmit information about sound and movement. Bundles contain tightly controlled numbers of actin-filled stereocilia, which are arranged in defined rows of precise heights. Indeed, many deafness mutations that disable hair-cell cytoskeletal proteins also disrupt bundles. Bundle assembly is a tractable problem in molecular and cellular systems biology; the sequence of structural changes in stereocilia is known, and a modest number of proteins may be involved. PMID:26229154

  3. National Partnership for Maternal Safety: Consensus Bundle on Obstetric Hemorrhage.

    PubMed

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-07-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and System Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation. PMID:26241269

  4. Topological T-duality for torus bundles with monodromy

    NASA Astrophysics Data System (ADS)

    Baraglia, David

    2015-05-01

    We give a simplified definition of topological T-duality that applies to arbitrary torus bundles. The new definition does not involve Chern classes or spectral sequences, only gerbes and morphisms between them. All the familiar topological conditions for T-duals are shown to follow. We determine necessary and sufficient conditions for existence of a T-dual in the case of affine torus bundles. This is general enough to include all principal torus bundles as well as torus bundles with arbitrary monodromy representations. We show that isomorphisms in twisted cohomology, twisted K-theory and of Courant algebroids persist in this general setting. We also give an example where twisted K-theory groups can be computed by iterating T-duality.

  5. National Partnership for Maternal Safety: Consensus Bundle on Venous Thromboembolism.

    PubMed

    D'Alton, Mary E; Friedman, Alexander M; Smiley, Richard M; Montgomery, Douglas M; Paidas, Michael J; D'Oria, Robyn; Frost, Jennifer L; Hameed, Afshan B; Karsnitz, Deborah; Levy, Barbara S; Clark, Steven L

    2016-01-01

    Obstetric venous thromboembolism is a leading cause of severe maternal morbidity and mortality. Maternal death from thromboembolism is amenable to prevention, and thromboprophylaxis is the most readily implementable means of systematically reducing the maternal death rate. Observational data support the benefit of risk-factor-based prophylaxis in reducing obstetric thromboembolism. This bundle, developed by a multidisciplinary working group and published by the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care, supports routine thromboembolism risk assessment for obstetric patients, with appropriate use of pharmacologic and mechanical thromboprophylaxis. Safety bundles outline critical clinical practices that should be implemented in every maternity unit. The safety bundle is organized into four domains: Readiness, Recognition, Response, and Reporting and Systems Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. PMID:27619099

  6. PWR FLECHT SEASET 163-Rod Bundle Flow Blockage Task data report. NRC/EPRI/Westinghouse report No. 13, August-October 1982

    SciTech Connect

    Loftus, M J; Hochreiter, L E; McGuire, M F; Valkovic, M M

    1983-10-01

    This report presents data from the 163-Rod Bundle Blow Blockage Task of the Full-Length Emergency Cooling Heat Transfer Systems Effects and Separate Effects Test Program (FLECHT SEASET). The task consisted of forced and gravity reflooding tests utilizing electrical heater rods with a cosine axial power profile to simulate PWR nuclear core fuel rod arrays. These tests were designed to determine effects of flow blockage and flow bypass on reflooding behavior and to aid in the assessment of computational models in predicting the reflooding behavior of flow blockage in rod bundle arrays.

  7. Reversible separation of single-walled carbon nanotubes in bundles

    SciTech Connect

    Sahoo, Sangeeta; Lastella, Sarah; Maranganti, Ravi; Sharma, Pradeep; Mallick, Govind; Karna, Shashi; Ajayan, Pulickel M.

    2008-08-25

    We show that electrostatic charging of nanotubes and the consequent repulsion can lead to reversible separation of individual single-walled carbon nanotubes in bundles. Low-energy electron beam irradiation leads to this completely reversible phenomenon. A simple semianalytical model is used to explain the observed separation mechanism. The reversibility of the separation process is attributed to discharging and thermal-fluctuation induced motion of the nanotubes in ambient air. Further, the separation impacts the electrical conductance of small nanotube bundled devices.

  8. Plantain fibre bundles isolated from Colombian agro-industrial residues.

    PubMed

    Gañán, Piedad; Zuluaga, Robin; Restrepo, Adriana; Labidi, Jalel; Mondragon, Iñaki

    2008-02-01

    Comestible fruit production from Musaceas plants is an important economical activity in developing countries like Colombia. However, it generates a large amount of agro-industrial residues. Some of them are a potential resource of natural fibres, which can be used as reinforcement for composite materials. In this work, a series of commercial plantain (Musa AAB, cv "Dominico Harton") fibre bundles extracted from pseudostem, leaf sheath and rachis agricultural wastes were analyzed. Mechanical decortication and biological retting processes were used during fiber extraction. No significant differences in composition of vascular bundles were observed for both extraction processes. Gross morphological characteristics and mechanical behavior have been evaluated. Conducting tissues with spiral-like arrangement are observed attached to fibre bundles. This fact suggests a big amount of these tissues in commercial plantain plants. Both used extraction methods are not enough to remove them. Pseudostem fibre bundles have higher specific strength and modulus and lower strain at break than leaf sheath and rachis fibre bundles, having values comparable to other lignocellulosic fibres bundles. PMID:17350832

  9. An evaluation of the impact of the ventilator care bundle.

    PubMed

    Crunden, Eddie; Boyce, Carolyn; Woodman, Helen; Bray, Barbara

    2005-01-01

    A number of interventions have been shown to improve the outcomes of patients who are invasively ventilated in intensive care units (ICUs). However, significant problems still exist in implementing research findings into clinical practice. The aim of this study was to assess whether the systematic and methodical implementation of evidence-based interventions encapsulated in a care bundle influenced length of ventilation and ICU length of stay (LOS). A ventilator care bundle was introduced within a general ICU and evaluated 1 year later. The care bundle was composed of four protocols that consisted of prophylaxis against peptic ulceration, prophylaxis against deep vein thrombosis, daily cessation of sedation and elevation of the patient's head and chest to at least 30 degrees to the horizontal. Compliance with the bundle was assessed, as was ICU LOS, ICU mortality and ICU/high-dependency unit patient throughput. Mean ICU LOS was reduced from 13-75 [standard deviation (SD) 19.11] days to 8.36 (SD 10.21) days (p<0.05). Mean ventilator days were reduced from 10.8 (SD 15.58) days to 6.1 (SD 8.88) days. Unit patient throughput increased by 30.1% and the number of invasively ventilated patients increased by 39.5%. Care bundles encourage the consistent and systematic application of evidence-based protocols used in particular treatment regimes. Since the introduction of the ventilator care bundle, length of ventilation and ICU LOS have reduced significantly. PMID:16161379

  10. Talin can crosslink actin filaments into both networks and bundles.

    PubMed

    Zhang, J; Robson, R M; Schmidt, J M; Stromer, M H

    1996-01-17

    The talin-actin interaction was examined by using negative staining and cosedimentation assays. At pH 6.4 and low ionic strength, talin extensively crosslinked actin filaments into both networks and bundles. The bundles consist of parallel actin filaments with a center-to-center distance of 13 nm, and talin crossbridges spaced at 36-nm intervals along the bundles. As pH was increased stepwise from 6.4 to 7.3, talin's bundling activity was decreased first, then its networking activity. Qualitatively similar results were obtained at pH 6.4 by increasing ionic strength. Chemical crosslinking indicated talin was present as a dimer from pH 6.4 to 7.3, with or without added KC1. The results show that talin can interact directly with actin filaments by formation of actin filament networks and bundles, with the bundles more sensitive to dissolution by increase in pH or ionic strength. PMID:8561791

  11. A Radiologist's Primer on Bundles and Care Episodes.

    PubMed

    Seidenwurm, David; Lexa, Frank James

    2016-09-01

    Bundled or episode payments are among the most heavily emphasized approaches to aligning incentives and promoting care coordination, efficiency, and accountability in health care redesign. Bundled or episode payments price a market basket of services for an entire episode of care with both a clearly defined trigger and termination. Because the radiologist is "ancillary" in many bundles, the specialty is often unaware of the phenomenon. This is likely to change rapidly. Radiology is pivotal in high-prevalence, high-impact care areas such as low back pain and stroke that are focuses of widely used system performance metrics. More important, radiology is central to the diagnosis and management of a wide range of important diagnostic issues in areas such as breast cancer, pulmonary nodules, and incidental findings. Three models of bundled care will probably involve radiology intimately in the near future. Pure radiology bundles might be constructed for breast cancer screening and diagnosis, and these could be priced on the basis of guideline-based best-practice frequencies of care events such as recall and biopsy. Clinical bundles, for example low back pain, could be priced on the basis of optimal imaging frequencies. Finally, pricing of imaging studies might include evidence-based frequencies of follow-up imaging for incidental findings. PMID:27210231

  12. Steady state temperature profiles in two simulated liquid metal reactor fuel assemblies with identical design specifications

    SciTech Connect

    Levin, A.E.; Carbajo, J.J.; Lloyd, D.B.; Montgomery, B.H.; Rose, S.D.; Wantland, J.L.

    1985-01-01

    Temperature data from steady state tests in two parallel, simulated liquid metal reactor fuel assemblies with identical design specifications have been compared to determine the extent to which they agree. In general, good agreement was found in data at low flows and in bundle-center data at higher flows. Discrepancies in the data wre noted near the bundle edges at higher flows. An analysis of bundle thermal boundary conditions showed that the possible eccentric placement of one bundle within the housing could account for these discrepancies.

  13. Coolant mass flow equalizer for nuclear fuel

    DOEpatents

    Betten, Paul R.

    1978-01-01

    The coolant mass flow distribution in a liquid metal cooled reactor is enhanced by restricting flow in sub-channels defined in part by the peripheral fuel elements of a fuel assembly. This flow restriction, which results in more coolant flow in interior sub-channels, is achieved through the use of a corrugated liner positioned between the bundle of fuel elements and the inner wall of the fuel assembly coolant duct. The corrugated liner is expandable to accommodate irradiation induced growth of fuel assembly components.

  14. External Verification of the Bundle Adjustment in Photogrammetric Software Using the Damped Bundle Adjustment Toolbox

    NASA Astrophysics Data System (ADS)

    Börlin, Niclas; Grussenmeyer, Pierre

    2016-06-01

    The aim of this paper is to investigate whether the Matlab-based Damped Bundle Adjustment Toolbox (DBAT) can be used to provide independent verification of the BA computation of two popular software—PhotoModeler (PM) and PhotoScan (PS). For frame camera data sets with lens distortion, DBAT is able to reprocess and replicate subsets of PM results with high accuracy. For lens-distortion-free data sets, DBAT can furthermore provide comparative results between PM and PS. Data sets for the discussed projects are available from the authors. The use of an external verification tool such as DBAT will enable users to get an independent verification of the computations of their software. In addition, DBAT can provide computation of quality parameters such as estimated standard deviations, correlation between parameters, etc., something that should be part of best practice for any photogrammetric software. Finally, as the code is free and open-source, users can add computations of their own.

  15. Time-dependent fiber bundles with local load sharing.

    PubMed

    Newman, W I; Phoenix, S L

    2001-02-01

    Fiber bundle models, where fibers have random lifetimes depending on their load histories, are useful tools in explaining time-dependent failure in heterogeneous materials. Such models shed light on diverse phenomena such as fatigue in structural materials and earthquakes in geophysical settings. Various asymptotic and approximate theories have been developed for bundles with various geometries and fiber load-sharing mechanisms, but numerical verification has been hampered by severe computational demands in larger bundles. To gain insight at large size scales, interest has returned to idealized fiber bundle models in 1D. Such simplified models typically assume either equal load sharing (ELS) among survivors, or local load sharing (LLS) where a failed fiber redistributes its load onto its two nearest flanking survivors. Such models can often be solved exactly or asymptotically in increasing bundle size, N, yet still capture the essence of failure in real materials. The present work focuses on 1D bundles under LLS. As in previous works, a fiber has failure rate following a power law in its load level with breakdown exponent rho. Surviving fibers under fixed loads have remaining lifetimes that are independent and exponentially distributed. We develop both new asymptotic theories and new computational algorithms that greatly increase the bundle sizes that can be treated in large replications (e.g., one million fibers in thousands of realizations). In particular we develop an algorithm that adapts several concepts and methods that are well-known among computer scientists, but relatively unknown among physicists, to dramatically increase the computational speed with no attendant loss of accuracy. We consider various regimes of rho that yield drastically different behavior as N increases. For 1/2< or =rho< or =1, ELS and LLS have remarkably similar behavior (they have identical lifetime distributions at rho=1) with approximate Gaussian bundle lifetime statistics and a

  16. Geometric Frustration Selects Morphology in Chiral Filament Bundles

    NASA Astrophysics Data System (ADS)

    Hall, Douglas; Bruss, Isaac; Barone, Justin; Grason, Gregory

    Assemblies of twisted filaments appear in a range of biological contexts, from extracellular filament bundles to amyloid fibrils. Owing to numerous distinctions in molecular structures and interactions underlying these diverse assemblies, a framework to predict and classify the basic mechanisms of structure formation in twisted filament assemblies is still lacking. In this study, we model how the size and shape of self-assembled fibers are controlled by competition between the elastic costs of inter-filament frustration, bending deformation of filaments and bundle surface energy. Exploiting a geometric mapping between inter-filament packing in twisted bundles and packing on positively-curved 2D surfaces, we show that the anisotropy of the bundle cross-section is determined by a single parameter describing the competition between elastic and bending costs. We compare the continuum model's predictions for stability of cylindrical and tape-like twisted morphologies to numerical simulations of cohesive filament bundles and observations of micron-scale amyloid fibers assembled from hydrolyzed protein fragments. Nsf (CAREER) DMR-0955760.

  17. CRYPTOCHROME2 in Vascular Bundles Regulates Flowering in Arabidopsis

    PubMed Central

    Endo, Motomu; Mochizuki, Nobuyoshi; Suzuki, Tomomi; Nagatani, Akira

    2007-01-01

    Plants make full use of light signals to determine the timing of flowering. In Arabidopsis thaliana, a blue/UV-A photoreceptor, CRYPTOCHROME 2 (cry2), and a red/far-red photoreceptor, PHYTOCHROME B (phyB), are two major photoreceptors that control flowering. The light stimuli for the regulation of flowering are perceived by leaves. We have recently shown that phyB expression in mesophyll but not in vascular bundles suppresses the expression of a key flowering regulator, FLOWERING LOCUS T (FT), in vascular bundles. In this study, we asked where in the leaf cry2 perceives light stimuli to regulate flowering. To answer this question, we established transgenic Arabidopsis lines in which the cry2–green fluorescent protein (GFP) fusion was expressed under the control of organ/tissue-specific promoters in a cry2-deficient mutant background. Analysis of these lines revealed that expression of cry2-GFP in vascular bundles, but not in epidermis or mesophyll, rescued the late flowering phenotype. We further confirmed that cry2-GFP expressed in vascular bundles increased FT expression only in vascular bundles. Hence, in striking contrast with phyB, cry2 most likely regulates FT expression in a cell-autonomous manner. PMID:17259260

  18. Variable recruitment in bundles of miniature pneumatic artificial muscles.

    PubMed

    DeLaHunt, Sylvie A; Pillsbury, Thomas E; Wereley, Norman M

    2016-01-01

    The natural compliance and force generation properties of pneumatic artificial muscles (PAMs) allow them to operate like human muscles in anthropomorphic robotic manipulators. Traditionally, manipulators use a single PAM or multiple PAMs actuated in unison in place of a human muscle. However, these standard manipulators can experience significant efficiency losses when operated outside their target performance ranges at low actuation pressures. This study considers the application of a variable recruitment control strategy to a parallel bundle of miniature PAMs as an attempt to mimic the selective recruitment of motor units in a human muscle. Bundles of miniature PAMs are experimentally characterized, their actuation behavior is modeled, and the efficiency gains and losses associated with the application of a variable recruitment control strategy are assessed. This bio-inspired control strategy allows muscle bundles to operate the fewest miniature PAMs necessary to achieve a desired performance objective, improving the muscle bundle's operating efficiency over larger ranges of force generation and displacement. The study also highlights the need for improved PAM fabrication techniques to facilitate the production of identical miniature PAMs for inclusion in muscle bundles. PMID:27623216

  19. Hair-bundle friction from transduction channels' gating forces

    NASA Astrophysics Data System (ADS)

    Bormuth, Volker; Barral, Jérémie; Joanny, Jean-François; Jülicher, Frank; Martin, Pascal

    2015-12-01

    Hearing starts when sound-evoked mechanical vibrations of the hair-cell bundle activate mechanosensitive ion channels, giving birth to an electrical signal. As for any mechanical system, friction impedes movements of the hair bundle and thus constrains the sensitivity and frequency selectivity of auditory transduction. We have shown recently that the opening and closing of the transduction channels produce internal frictional forces that can dominate viscous drag on the micrometer-sized hair bundle and thus provide a major source of damping [2]. We develop here a physical theory of passive hair-bundle mechanics that explains the origin of channel friction. We show that channel friction can be understood quantitatively by coupling the dynamics of the conformational change associated with channel gating to tip-link tension. As a result, varying channel properties affects friction, with faster channels producing smaller friction. The analysis emphasizes the dual role of transduction channels' gating forces, which affect both hair-bundle stiffness and drag. Friction originating from gating of ion channels is a general concept that is relevant to all mechanosensitive channels.

  20. Hierarchical streamline bundles for visualizing 2D flow fields.

    SciTech Connect

    Shene, Ching-Kuang; Wang, Chaoli; Yu, Hongfeng; Chen, Jacqueline H.

    2010-08-01

    We present hierarchical streamline bundles, a new approach to simplifying and visualizing 2D flow fields. Our method first densely seeds a flow field and produces a large number of streamlines that capture important flow features such as critical points. Then, we group spatially neighboring and geometrically similar streamlines to construct a hierarchy from which we extract streamline bundles at different levels of detail. Streamline bundles highlight multiscale flow features and patterns through a clustered yet non-cluttered display. This selective visualization strategy effectively accentuates visual foci and therefore is able to convey the desired insight into the flow fields. The hierarchical streamline bundles we have introduced offer a new way to characterize and visualize the flow structure and patterns in multiscale fashion. Streamline bundles highlight critical points clearly and concisely. Exploring the hierarchy allows a complete visualization of important flow features. Thanks to selective streamline display and flexible LOD refinement, our multiresolution technique is scalable and is promising for viewing large and complex flow fields. In the future, we would like to seek a cost-effective way to generate streamlines without enforcing the dense seeding condition. We will also extend this approach to handle real-world 3D complex flow fields.

  1. Thermal imaging through infrared fiber/waveguides bundles

    NASA Astrophysics Data System (ADS)

    Gannot, Israel; Goren, Alon; Rave, Eran; Katzir, Abraham; Gopal, Veena; Revezin, Gregory; Harrington, James A.

    2004-06-01

    Trans-endoscopic Infrared Imaging (IRI) relates the possibility to conduct IRI diagnosis of internal body surfaces under minimal invasiveness. It may also be utilized to control and to optimize the thermal interactions and the potential side effects during Minimally Invasive Surgeries (MIS). However, transferring the thermal images transendoscopically requires the usage of IR imaging bundles, which are neither yet mature nor commercially available. In our setup we have used two basic types of recently-developed imaging bundles: Ag/AgI-coated Hollow Glass Waveguide (HGW) bundles and Silver Halide (AgClBr) core-clad fiber bundles. The optical setup system was consisted of IR optics (e.g. ZnSe lenses, reflective objectives) and a thermal IR camera. We have succeeded to image objects through the bundles, such as various shapes of electrically heated wires, ex-vivo biological phantoms (samples of porcine stomach) and in-vivo phantom models (mice) irradiated by CO2 laser. Measurements were conducted for both - static and dynamic object states.

  2. Reaction–diffusion model of hair-bundle morphogenesis

    PubMed Central

    Jacobo, Adrian; Hudspeth, A. J.

    2014-01-01

    The hair bundle, an apical specialization of the hair cell composed of several rows of regularly organized stereocilia and a kinocilium, is essential for mechanotransduction in the ear. Its precise organization allows the hair bundle to convert mechanical stimuli to electrical signals; mutations that alter the bundle’s morphology often cause deafness. However, little is known about the proteins involved in the process of morphogenesis and how the structure of the bundle arises through interactions between these molecules. We present a mathematical model based on simple reaction–diffusion mechanisms that can reproduce the shape and organization of the hair bundle. This model suggests that the boundary of the cell and the kinocilium act as signaling centers that establish the bundle’s shape. The interaction of two proteins forms a hexagonal Turing pattern—a periodic modulation of the concentrations of the morphogens, sustained by local activation and long-range inhibition of the reactants—that sets a blueprint for the location of the stereocilia. Finally we use this model to predict how different alterations to the system might impact the shape and organization of the hair bundle. PMID:25313064

  3. FUEL ELEMENT FOR NUCLEAR REACTORS

    DOEpatents

    Dickson, J.J.

    1963-09-24

    A method is described whereby fuel tubes or pins are cut, loaded with fuel pellets and a heat transfer medium, sealed at each end with slotted fittings, and assembled into a rectangular tube bundle to form a fuel element. The tubes comprising the fuel element are laterally connected between their ends by clips and tabs to form a linear group of spaced parallel tubes, which receive their vertical support by resting on a grid. The advantages of this method are that it permits elimination of structural material (e.g., fuel-element cans) within the reactor core, and removal of at least one fuel pin from an element and replacement thereof so that a burnable poison may be utilized during the core lifetime. (AEC)

  4. Experiment data report for Multirod Burst Test (MRBT) Bundle B-5. [PWR

    SciTech Connect

    Chapman, R H; Crowley, J L; Longest, A W

    1984-08-01

    A reference source of MRBT bundle B-5 test data is presented with interpretation limited to that necessary to understand pertinent features of the test. Primary objectives of this 8 x 8 multirod burst test were to investigate the effects of array size and rod-to-rod interactions on cladding deformation in the high-alpha-Zircaloy temperature range under simulated light-water reactor loss-of-coolant accident (LOCA) conditions. B-5 test conditions, nominally the same as used in an earlier 4 x 4 (B-3) test, simulated the adiabatic heatup (reheat) phase of an LOCA and were conducive to large deformation. The fuel pin simulators were electrically heated (average linear power generation of 3.0 kW/m) and were slightly cooled with a very low flow (Re approx. 140) of low-pressure superheated steam. The cladding temperature increased from the initial temperature (335/sup 0/C) to the burst temperature at a rate of 9.8/sup 0/C/s. The simulators burst in a very narrow temperature range, with an average of 768/sup 0/C. Cladding burst strain ranged from 32% to 95%, with an average of 61%. Volumetric expansion over the heated length of the cladding ranged from 35% to 79%, with an average of 52%. The results clearly show deformation was greater in the bundle interior and suggest rod-to-rod mechanical interactions caused axial propagation of the deformation.

  5. In-Situ Imaging and Quantification of Tritium Surface Contamination via Coherent Fiber Bundle

    SciTech Connect

    Charles A. Gentile; John J. Parker; Stewart J. Zweben

    2001-11-12

    Princeton Plasma Physics Laboratory (PPPL) has developed a method of imaging tritium on in-situ surfaces for the purpose of real-time data collection. This method expands upon a previous tritium imaging concept, also developed at PPPL. Enhancements include an objective lens coupled to the entry aperture of a coherent fiber optic (CFO) bundle, and a relay lens connecting the exit aperture of the fiber bundle to an intensifier tube and a charge-coupled device (CCD) camera. The system has been specifically fabricated for use in determining tritium concentrations on first wall materials. One potential complication associated with the development of D-T [deuterium-tritium] fueled fusion reactors is the deposition of tritium (i.e., co-deposited layer) on the surface of the primary wall of the vacuum vessel. It would be advantageous to implement a process to accurately determine tritium distribution on these inner surfaces. This fiber optic imaging device provides a highly practical method for determining the location, concentration, and activity of surface tritium deposition. In addition, it can be employed for detection of tritium ''hot-spots'' and ''hide-out'' regions present on the surfaces being imaged.

  6. The Annular Two-phase Flow on Rod Bundle: The Effects of Spacers

    NASA Astrophysics Data System (ADS)

    Kunugi, Tomoaki; Pham, Son; Kawara, Zensaku; Yokomine, Takehiko

    2013-11-01

    The annular two-phase flow on rod bundle keeps an important role in many heat exchange systems but our knowledge about it, especially the interaction between the liquid film flowing on the rods' surfaces and the spacers is very limited. This study is aimed to the investigation of how the spacer affects the disturbance waves of the flow in a 3 × 3 simulating BWR fuel rod bundle test section. Firstly, the characteristics of the disturbance waves at both upstream and downstream locations of the spacer were obtained by using reflected light arrangement with a high speed camera Phantom V7.1 (Vision Research Inc.) and a Nikon macro lens 105mm f/2.8. The data showed that the parameters such as frequency and circumferential coherence of the disturbance waves are strongly modified when they go through the spacer. Then, the observations at the locations right before and after the spacer were performed by using the back light arrangement with the same high speed camera and a Cassegrain optical system (Seika Cooperation). The obtained images at micro-scale of time and space provided the descriptions of the wavy interface behaviors right before and after the spacer as well as different droplets creation processes caused by the presence of this spacer.

  7. System for supporting bundled tube segments within a combustor

    DOEpatents

    Melton, Patrick Benedict

    2016-03-01

    A system for supporting bundled tube segments within a combustor includes an annular sleeve that extends circumferentially and axially within the combustor, a support lug that extends radially inward from the annular sleeve and an annular support frame that is disposed within the annular sleeve. The annular support frame includes an inner ring portion, an outer ring portion and a plurality of spokes that extend radially between the inner and outer ring portions. The inner ring portion, the outer ring portion and the plurality of spokes define an annular array of openings for receiving a respective bundled tube segment. The inner ring portion is connected to each bundled tube segment and the outer ring portion is coupled to the support lug.

  8. β-Peptide bundles: Design. Build. Analyze. Biosynthesize.

    PubMed

    Wang, Pam S P; Schepartz, Alanna

    2016-06-14

    Peptides containing β-amino acids are unique non-natural polymers known to assemble into protein-like tertiary and quaternary structures. When composed solely of β-amino acids, the structures formed, defined assemblies of 14-helices called β-peptide bundles, fold cooperatively in water solvent into unique and discrete quaternary assemblies that are highly thermostable, bind complex substrates and metal ion cofactors, and, in certain cases, catalyze chemical reactions. In this Perspective, we recount the design and elaboration of β-peptide bundles and provide an outlook on recent, unexpected discoveries that could influence research on β-peptides and β-peptide bundles (and β-amino acid-containing proteins) for decades to come. PMID:27146019

  9. Stable parabolic Higgs bundles as asymptotically stable decorated swamps

    NASA Astrophysics Data System (ADS)

    Beck, Nikolai

    2016-06-01

    Parabolic Higgs bundles can be described in terms of decorated swamps, which we studied in a recent paper. This description induces a notion of stability of parabolic Higgs bundles depending on a parameter, and we construct their moduli space inside the moduli space of decorated swamps. We then introduce asymptotic stability of decorated swamps in order to study the behaviour of the stability condition as one parameter approaches infinity. The main result is the existence of a constant, such that stability with respect to parameters greater than this constant is equivalent to asymptotic stability. This implies boundedness of all decorated swamps which are semistable with respect to some parameter. Finally, we recover the usual stability condition of parabolic Higgs bundles as asymptotic stability.

  10. Magnetic Propulsion of Microswimmers with DNA-Based Flagellar Bundles

    PubMed Central

    2016-01-01

    We show that DNA-based self-assembly can serve as a general and flexible tool to construct artificial flagella of several micrometers in length and only tens of nanometers in diameter. By attaching the DNA flagella to biocompatible magnetic microparticles, we provide a proof of concept demonstration of hybrid structures that, when rotated in an external magnetic field, propel by means of a flagellar bundle, similar to self-propelling peritrichous bacteria. Our theoretical analysis predicts that flagellar bundles that possess a length-dependent bending stiffness should exhibit a superior swimming speed compared to swimmers with a single appendage. The DNA self-assembly method permits the realization of these improved flagellar bundles in good agreement with our quantitative model. DNA flagella with well-controlled shape could fundamentally increase the functionality of fully biocompatible nanorobots and extend the scope and complexity of active materials. PMID:26821214

  11. Infinite number of MSSMs from heterotic line bundles?

    NASA Astrophysics Data System (ADS)

    Groot Nibbelink, Stefan; Loukas, Orestis; Ruehle, Fabian; Vaudrevange, Patrick K. S.

    2015-08-01

    We consider heterotic E8×E8 supergravity compactified on smooth Calabi-Yau manifolds with line bundle gauge backgrounds. Infinite sets of models that satisfy the Bianchi identities and flux quantization conditions can be constructed by letting their background flux quanta grow without bound. Even though we do not have a general proof, we find that all examples are at the boundary of the theory's validity: the Donaldson-Uhlenbeck-Yau equations, which can be thought of as vanishing D-term conditions, cannot be satisfied inside the Kähler cone unless a growing number of scalar vacuum expectation values is switched on. As they are charged under various line bundles simultaneously, the gauge background gets deformed by these VEVs to a non-Abelian bundle. In general, our physical expectation is that such infinite sets of models should be impossible, since they never seem to occur in exact conformal field theory constructions.

  12. Magnetic Propulsion of Microswimmers with DNA-Based Flagellar Bundles.

    PubMed

    Maier, Alexander M; Weig, Cornelius; Oswald, Peter; Frey, Erwin; Fischer, Peer; Liedl, Tim

    2016-02-10

    We show that DNA-based self-assembly can serve as a general and flexible tool to construct artificial flagella of several micrometers in length and only tens of nanometers in diameter. By attaching the DNA flagella to biocompatible magnetic microparticles, we provide a proof of concept demonstration of hybrid structures that, when rotated in an external magnetic field, propel by means of a flagellar bundle, similar to self-propelling peritrichous bacteria. Our theoretical analysis predicts that flagellar bundles that possess a length-dependent bending stiffness should exhibit a superior swimming speed compared to swimmers with a single appendage. The DNA self-assembly method permits the realization of these improved flagellar bundles in good agreement with our quantitative model. DNA flagella with well-controlled shape could fundamentally increase the functionality of fully biocompatible nanorobots and extend the scope and complexity of active materials. PMID:26821214

  13. Betti numbers of graded modules and cohomology of vector bundles

    NASA Astrophysics Data System (ADS)

    Eisenbud, David; Schreyer, Frank-Olaf

    2009-07-01

    In the remarkable paper Graded Betti numbers of Cohen-Macaulay modules and the multiplicity conjecture, Mats Boij and Jonas Soederberg conjectured that the Betti table of a Cohen-Macaulay module over a polynomial ring is a positive linear combination of Betti tables of modules with pure resolutions. We prove a strengthened form of their conjectures. Applications include a proof of the Multiplicity Conjecture of Huneke and Srinivasan and a proof of the convexity of a fan naturally associated to the Young lattice. With the same tools we show that the cohomology table of any vector bundle on projective space is a positive rational linear combination of the cohomology tables of what we call supernatural vector bundles. Using this result we give new bounds on the slope of a vector bundle in terms of its cohomology.

  14. Overview of rod-bundle thermal-hydraulic analysis

    SciTech Connect

    Sha, W.T.

    1980-11-01

    Three methods used in rod-bundle thermal-hydraulic analysis are summarized. These methods are: (1) subchannel analysis, and its inherent assumptions are clearly stated; (2) porous medium formulation with volume porosity, surface permeability, distributed resistance and distributed heat source (sink) - the concept of surface permeability is new in porous medium formulation, and greatly facilitates modeling anisotropic effects; and (3) benchmark rod-bundle thermal-hydraulic analysis using a boundary-fitted coordinate system, and it represents the most rigorous method to date. For laminar flow, this method gives solutions without any assumptions and it requires information on rod bundle geometry and thermal physical properties of the fluid. Basic limitations and merits of each method are discussed in detail. 19 refs., 6 figs., 1 tab.

  15. On some transverse geometrical structures of lifted foliation to its conormal bundle.

    PubMed

    Ida, Cristian; Oană, Alexandru

    2015-01-01

    We consider the lift of a foliation to its conormal bundle and some transverse geometrical structures associated with this foliation are studied. We introduce a good vertical connection on the conormal bundle and, moreover, if the conormal bundle is endowed with a transversal Cartan metric, we obtain that the lifted foliation to its conormal bundle is a Riemannian one. Also, some transversally framed f(3, ε)-structures of corank 2 on the normal bundle of lifted foliation to its conormal bundle are introduced and an almost (para)contact structure on a transverse Liouville distribution is obtained. PMID:25834835

  16. Phase Transition to Bundles of Flexible Supramolecular Polymers

    NASA Astrophysics Data System (ADS)

    Huisman, B. A. H.; Bolhuis, P. G.; Fasolino, A.

    2008-05-01

    We report Monte Carlo simulations of the self-assembly of supramolecular polymers based on a model of patchy particles. We find a first-order phase transition, characterized by hysteresis and nucleation, toward a solid bundle of polymers, of length much greater than the average gas phase length. We argue that the bundling transition is the supramolecular equivalent of the sublimation transition, which results from a weak chain-chain interaction. We provide a qualitative equation of state that gives physical insight beyond the specific values of the parameters used in our simulations.

  17. One-sided ejaculation of echidna sperm bundles.

    PubMed

    Johnston, S D; Smith, B; Pyne, M; Stenzel, D; Holt, W V

    2007-12-01

    We report for the first time an unusual ejaculatory mechanism in the short-beaked echidna in which each side of the bilaterally symmetrical, rosettelike glans penis is used alternately, with the other being shut down. This is unparalleled in mammals but is reminiscent of the use of hemipenes in squamate reptiles, providing further reproductive evidence of a sauropsidian lineage in the Monotremata. Further, we describe the occurrence of motile sperm bundles in ejaculated echidna semen and provide scanning electron micrographs of their morphology. Sperm bundling appears to confer increased sperm motility, which may provide the potential for sperm competition between males. PMID:18171162

  18. Medicare bundled payment: what is it worth to you?

    PubMed

    Harris, John; Elizondo, Idette; Isdaner, Andrew

    2014-01-01

    Hospital leaders who are contemplating participation in a bundled payment initiative should first assess current circumstances to determine the extent of the opportunity for their organizations. Those who have decided conditions are favorable for such an initiative should next perform a financial assessment that includes modeling direct contract results, assessing the financial impact of reduced utilization and of improved clinical care and operations, and evaluating the net financial impact. Hospital executives also should understand the competitive and strategic benefits that bundled payment offers. PMID:24511781

  19. Capture and manipulation of hybrid DNAs by carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Li, Zhenhai; Yang, Wei

    2010-05-01

    When approached from both sides, a piece of single-duplex-single DNA may be drawn into the inlets of two bundles of carbon nanotubes. This provides opportunities to manipulate the DNA by two bundles of nanotubes. The capture and manipulation processes envisaged above are simulated by molecular dynamics in this work. The radius of the carbon nanotube and the ambient temperature show the effects on the spontaneous insertion of DNA strands. This procedure, if successful, could be used for capturing expectant sdsDNAs, with subsequent manipulation to pull or to unzip the captured DNA.

  20. Artificial metalloenzymes derived from three-helix bundles

    PubMed Central

    Tebo, Alison G.; Pecoraro, Vincent L.

    2015-01-01

    Three-helix bundles and coiled-coil motifs are well-established de novo designed scaffolds that have been investigated for their metal-binding and catalytic properties. Satisfaction of the primary coordination sphere for a given metal is sufficient to introduce catalytic activity and a given structure may catalyze different reactions dependent on the identity of the incorporated metal. Here we describe recent contributions in the de novo design of metalloenzymes based on three-helix bundles and coiled-coil motifs, focusing on non-heme systems for hydrolytic and redox chemistry. PMID:25579452

  1. Experimental study of heat transfer in a 7-element bundle cooled with supercritical Freon-12

    SciTech Connect

    Richards, G.; Shelegov, A. S.; Kirillov, P. L.; Pioro, I. L.; Harvel, G.

    2012-07-01

    Experimental data on Supercritical-Water (SCW) cooled bundles are very limited. Major problems with performing such experiments are technical difficulties in testing and experimental costs at high pressures, temperatures and heat fluxes. Also, there are only a few SCW experimental setups currently in the world capable of providing data. Supercritical Water-cooled nuclear Reactors (SCWRs), as one of the six concepts of Generation IV reactors, cannot be designed without such data. Therefore, a preliminary approach uses modeling fluids such as carbon dioxide and refrigerants instead of water is practical. In particularly, experiments in supercritical refrigerant-cooled bundles can be used. One of the SC modeling fluids typically used is Freon-12 (R-12) with the critical pressure of 4.136 MPa and the critical temperature of 111.97 deg. C. These conditions correspond to the critical pressure of 22.064 MPa and critical temperature of 373.95 deg. C in water. A set of experimental data obtained at the Inst. of Physics and Power Engineering (IPPE, Obninsk, Russia) in a vertically-oriented bundle cooled with supercritical R-12 was analyzed. This dataset consisted of 20 runs. The test section was 7-element bundle installed in a hexagonal flow channel with 3 grid spacers. Data was collected at pressures of approximately 4.65 MPa for several different combinations of wall and bulk-fluid temperatures that were below, at, or above the pseudo-critical temperature. The values of mass flux were ranged from 400 to 1320 kg/m{sup 2}s and inlet temperatures ranged from 72 to 120 deg. C. The test section consisted of fuel-element simulators that were 9.5 mm in OD with the total heated length of about 1 m. Bulk-fluid and wall temperature profiles were recorded using a combination of 8 different thermocouples. Analysis of the data has confirmed that there are three distinct heat-transfer regimes for forced convention in supercritical fluids: 1) Normal heat transfer; 2) Deteriorated heat

  2. Fuel flexible fuel injector

    SciTech Connect

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  3. A Method of Assembling Compact Coherent Fiber-Optic Bundles

    NASA Technical Reports Server (NTRS)

    Martin, Stefan; Liu, Duncan; Levine, Bruce Martin; Shao, Michael; Wallace, James

    2007-01-01

    A method of assembling coherent fiber-optic bundles in which all the fibers are packed together as closely as possible is undergoing development. The method is based, straightforwardly, on the established concept of hexagonal close packing; hence, the development efforts are focused on fixtures and techniques for practical implementation of hexagonal close packing of parallel optical fibers.

  4. Heat transfer and fluid friction in bundles of twisted tubes

    NASA Astrophysics Data System (ADS)

    Dzyubenko, B. V.; Dreitser, G. A.

    1986-06-01

    The results of heat-transfer and friction studies in bundles of twisted tubes and rods with spiral wire-wrap spacers are analyzed, and recommendations are given for calculating the heat-transfer coefficient in heat exchangers using twisted tubes.

  5. Ion adsorption mechanism of bundled single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yoshida, Y.; Tsutsui, M.; Al-zubaidi, A.; Ishii, Y.; Kawasaki, S.

    2016-07-01

    In order to elucidate ion adsorption mechanism of bundled single-walled carbon nanotubes (SWCNTs), in situ synchrotron XRD measurements of SWCNT electrode in alkali halide aqueous electrolyte at several applied potentials were performed. It was found that the surface inside SWCNT is the important ion adsorption site.

  6. Structureless Bundle Adjustment with Self-Calibration Using Accumulated Constraints

    NASA Astrophysics Data System (ADS)

    Cefalu, A.; Haala, N.; Fritsch, D.

    2016-06-01

    Bundle adjustment based on collinearity is the most widely used optimization method within image based scene reconstruction. It incorporates observed image coordinates, exterior and intrinsic camera parameters as well as object space coordinates of the observed points. The latter dominate the resulting nonlinear system, in terms of the number of unknowns which need to be estimated. In order to reduce the size of the problem regarding memory footprint and computational effort, several approaches have been developed to make the process more efficient, e.g. by exploitation of sparsity or hierarchical subdivision. Some recent developments express the bundle problem through epipolar geometry and scale consistency constraints which are free of object space coordinates. These approaches are usually referred to as structureless bundle adjustment. The number of unknowns in the resulting system is drastically reduced. However, most work in this field is focused on optimization towards speed and considers calibrated cameras, only. We present our work on structureless bundle adjustment, focusing on precision issues as camera calibration and residual weighting. We further investigate accumulation of constraint residuals as an approach to decrease the number of rows of the Jacobian matrix.

  7. Appraising Lexical Bundles in Mathematics Classroom Discourse: Obligation and Choice

    ERIC Educational Resources Information Center

    Herbel-Eisenmann, Beth; Wagner, David

    2010-01-01

    Working from a large corpus of transcripts from secondary mathematics classrooms, we identify patterns of speech that encode interpersonal positioning. We extend our analysis from a previous article (Herbel-Eisenmann, Wagner & Cortes, Educ Stud Math, 2010, in press), in which we introduced a concept from corpus linguistics--a "lexical bundle,"…

  8. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    ERIC Educational Resources Information Center

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  9. Non-Euclidean geometry of twisted filament bundle packing

    PubMed Central

    Bruss, Isaac R.; Grason, Gregory M.

    2012-01-01

    Densely packed and twisted assemblies of filaments are crucial structural motifs in macroscopic materials (cables, ropes, and textiles) as well as synthetic and biological nanomaterials (fibrous proteins). We study the unique and nontrivial packing geometry of this universal material design from two perspectives. First, we show that the problem of twisted bundle packing can be mapped exactly onto the problem of disc packing on a curved surface, the geometry of which has a positive, spherical curvature close to the center of rotation and approaches the intrinsically flat geometry of a cylinder far from the bundle center. From this mapping, we find the packing of any twisted bundle is geometrically frustrated, as it makes the sixfold geometry of filament close packing impossible at the core of the fiber. This geometrical equivalence leads to a spectrum of close-packed fiber geometries, whose low symmetry (five-, four-, three-, and twofold) reflect non-Euclidean packing constraints at the bundle core. Second, we explore the ground-state structure of twisted filament assemblies formed under the influence of adhesive interactions by a computational model. Here, we find that the underlying non-Euclidean geometry of twisted fiber packing disrupts the regular lattice packing of filaments above a critical radius, proportional to the helical pitch. Above this critical radius, the ground-state packing includes the presence of between one and six excess fivefold disclinations in the cross-sectional order. PMID:22711799

  10. Fission Yeast Scp3 Potentially Maintains Microtubule Orientation through Bundling

    PubMed Central

    Ozaki, Kanako; Chikashige, Yuji; Hiraoka, Yasushi; Matsumoto, Tomohiro

    2015-01-01

    Microtubules play important roles in organelle transport, the maintenance of cell polarity and chromosome segregation and generally form bundles during these processes. The fission yeast gene scp3+ was identified as a multicopy suppressor of the cps3-81 mutant, which is hypersensitive to isopropyl N-3-chlorophenylcarbamate (CIPC), a poison that induces abnormal multipolar spindle formation in higher eukaryotes. In this study, we investigated the function of Scp3 along with the effect of CIPC in the fission yeast Schizosaccharomyces pombe. Microscopic observation revealed that treatment with CIPC, cps3-81 mutation and scp3+ gene deletion disturbed the orientation of microtubules in interphase cells. Overexpression of scp3+ suppressed the abnormal orientation of microtubules by promoting bundling. Functional analysis suggested that Scp3 functions independently from Ase1, a protein largely required for the bundling of the mitotic spindle. A strain lacking the ase1+ gene was more sensitive to CIPC, with the drug affecting the integrity of the mitotic spindle, indicating that CIPC has a mitotic target that has a role redundant with Ase1. These results suggested that multiple systems are independently involved to ensure microtubule orientation by bundling in fission yeast. PMID:25767875