Defects in flexoelectric solids
Mao, Sheng; Purohit, Prashant K.
2015-11-01
A solid is said to be flexoelectric when it polarizes in proportion to strain gradients. Since strain gradients are large near defects, we expect the flexoelectric effect to be prominent there and decay away at distances much larger than a flexoelectric length scale. Here, we quantify this expectation by computing displacement, stress and polarization fields near defects in flexoelectric solids. For point defects we recover some well known results from strain gradient elasticity and non-local piezoelectric theories, but with different length scales in the final expressions. For edge dislocations we show that the electric potential is a maximum in the vicinity of the dislocation core. We also estimate the polarized line charge density of an edge dislocation in an isotropic flexoelectric solid which is in agreement with some measurements in ice. We perform an asymptotic analysis of the crack tip fields in flexoelectric solids and show that our results share some features from solutions in strain gradient elasticity and piezoelectricity. We also compute the energy release rate for cracks using simple crack face boundary conditions and use them in classical criteria for crack growth to make predictions. Our analysis can serve as a starting point for more sophisticated analytic and computational treatments of defects in flexoelectric solids which are gaining increasing prominence in the field of nanoscience and nanotechnology.
Motor-mediated bidirectional transport along an antipolar microtubule bundle: a mathematical model.
Lin, Congping; Ashwin, Peter; Steinberg, Gero
2013-05-01
Long-distance bidirectional transport of organelles depends on the coordinated motion of various motor proteins on the cytoskeleton. Recent quantitative live cell imaging in the elongated hyphal cells of Ustilago maydis has demonstrated that long-range motility of motors and their endosomal cargo occurs on unipolar microtubules (MTs) near the extremities of the cell. These MTs are bundled into antipolar bundles within the central part of the cell. Dynein and kinesin-3 motors coordinate their activity to move early endosomes (EEs) in a bidirectional fashion where dynein drives motility towards MT minus ends and kinesin towards MT plus ends. Although this means that one can easily assign the drivers of bidirectional motion in the unipolar section, the bipolar orientations in the bundle mean that it is possible for either motor to drive motion in either direction. In this paper we use a multilane asymmetric simple exclusion process modeling approach to simulate and investigate phases of bidirectional motility in a minimal model of an antipolar MT bundle. In our model, EE cargos (particles) change direction on each MT with a turning rate Ω and there is switching between MTs in the bundle at the minus ends. At these ends, particles can hop between MTs with rate q(1) on passing from a unipolar to a bipolar section (the obstacle-induced switching rate) or q(2) on passing in the other direction (the end-induced switching rate). By a combination of numerical simulations and mean-field approximations, we investigate the distribution of particles along the MTs for different values of these parameters and of Θ, the overall density of particles within this closed system. We find that even if Θ is low, the system can exhibit a variety of phases with shocks in the density profiles near plus and minus ends caused by queuing of particles. We discuss how the parameters influence the type of particle that dominates active transport in the bundle.
Motor-mediated bidirectional transport along an antipolar microtubule bundle: A mathematical model
Lin, Congping; Ashwin, Peter; Steinberg, Gero
2013-05-01
Long-distance bidirectional transport of organelles depends on the coordinated motion of various motor proteins on the cytoskeleton. Recent quantitative live cell imaging in the elongated hyphal cells of Ustilago maydis has demonstrated that long-range motility of motors and their endosomal cargo occurs on unipolar microtubules (MTs) near the extremities of the cell. These MTs are bundled into antipolar bundles within the central part of the cell. Dynein and kinesin-3 motors coordinate their activity to move early endosomes (EEs) in a bidirectional fashion where dynein drives motility towards MT minus ends and kinesin towards MT plus ends. Although this means that one can easily assign the drivers of bidirectional motion in the unipolar section, the bipolar orientations in the bundle mean that it is possible for either motor to drive motion in either direction. In this paper we use a multilane asymmetric simple exclusion process modeling approach to simulate and investigate phases of bidirectional motility in a minimal model of an antipolar MT bundle. In our model, EE cargos (particles) change direction on each MT with a turning rate Ω and there is switching between MTs in the bundle at the minus ends. At these ends, particles can hop between MTs with rate q1 on passing from a unipolar to a bipolar section (the obstacle-induced switching rate) or q2 on passing in the other direction (the end-induced switching rate). By a combination of numerical simulations and mean-field approximations, we investigate the distribution of particles along the MTs for different values of these parameters and of Θ, the overall density of particles within this closed system. We find that even if Θ is low, the system can exhibit a variety of phases with shocks in the density profiles near plus and minus ends caused by queuing of particles. We discuss how the parameters influence the type of particle that dominates active transport in the bundle.
Motor-free actin bundle contractility driven by molecular crowding
Schnauß, Jörg; Schuldt, Carsten; Schmidt, B U Sebastian; Glaser, Martin; Strehle, Dan; Heussinger, Claus; Käs, Josef A
2015-01-01
Modeling approaches of suspended, rod-like particles and recent experimental data have shown that depletion forces display different signatures depending on the orientation of these particles. It has been shown that axial attraction of two rods yields contractile forces of 0.1pN that are independent of the relative axial shift of the two rods. Here, we measured depletion-caused interactions of actin bundles extending the phase space of single pairs of rods to a multi-particle system. In contrast to a filament pair, we found forces up to 3pN . Upon bundle relaxation forces decayed exponentially with a mean decay time of 3.4s . These different dynamics are explained within the frame of a mathematical model by taking pairwise interactions to a multi-filament scale. The macromolecular content employed for our experiments is well below the crowding of cells. Thus, we propose that arising forces can contribute to biological force generation without the need to convert chemical energy into mechanical work.
Drechsler, Hauke; McAinsh, Andrew D
2016-03-22
Human Kinesin-12 (hKif15) plays a crucial role in assembly and maintenance of the mitotic spindle. These functions of hKif15 are partially redundant with Kinesin-5 (Eg5), which can cross-link and drive the extensile sliding of antiparallel microtubules. Although both motors are known to be tetramers, the functional properties of hKif15 are less well understood. Here we reveal how single or multiple Kif15 motors can cross-link, transport, and focus the plus-ends of intersecting microtubules. During transport, Kif15 motors step simultaneously along both microtubules with relative microtubule transport driven by a velocity differential between motor domain pairs. Remarkably, this differential is affected by the underlying intersection geometry: the differential is low on parallel and extreme on antiparallel microtubules where one motor domain pair becomes immobile. As a result, when intersecting microtubules are antiparallel, canonical transport of one microtubule along the other is allowed because one motor is firmly attached to one microtubule while it is stepping on the other. When intersecting microtubules are parallel, however, Kif15 motors can drive (biased) parallel sliding because the motor simultaneously steps on both microtubules that it cross-links. These microtubule rearrangements will focus microtubule plus-ends and finally lead to the formation of parallel bundles. At the same time, Kif15 motors cooperate to suppress catastrophe events at polymerizing microtubule plus-ends, raising the possibility that Kif15 motors may synchronize the dynamics of bundles that they have assembled. Thus, Kif15 is adapted to operate on parallel microtubule substrates, a property that clearly distinguishes it from the other tetrameric spindle motor, Eg5.
A peridynamic approach to flexoelectricity
Roy, Pranesh
2016-01-01
A flexoelectric peridynamic (PD) theory is proposed. Using the PD framework, the formulation introduces, perhaps for the first time, a nanoscale flexoelectric coupling that entails non-uniform strain in centrosymmetric dielectrics. This potentially enables PD modeling of a large class of phenomena in solid dielectrics involving cracks, discontinuities etc. wherein large strain gradients are present and the classical electromechanical theory based on partial differential equations do not directly apply. Derived from Hamilton's principle, PD electromechanical equations are shown to satisfy the global balance requirements. Linear PD constitutive equations reflect the electromechanical coupling effect, with the mechanical force state affected by the polarization state and the electrical force state in turn by the displacement state. An analytical solution of the PD electromechanical equations in the integral form is presented for the static case when a point mechanical force and a point electric force act in a th...
Flexoelectricity in barium strontium titanate thin film
Energy Technology Data Exchange (ETDEWEB)
Kwon, Seol Ryung; Huang, Wenbin; Yuan, Fuh-Gwo; Jiang, Xiaoning, E-mail: xjiang5@ncsu.edu [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Shu, Longlong [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Electronic Materials Research Laboratory, International Center for Dielectric Research, Xi' an Jiao Tong University, Xi' an, Shaanxi 710049 (China); Maria, Jon-Paul [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
2014-10-06
Flexoelectricity, the linear coupling between the strain gradient and the induced electric polarization, has been intensively studied as an alternative to piezoelectricity. Especially, it is of interest to develop flexoelectric devices on micro/nano scales due to the inherent scaling effect of flexoelectric effect. Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} thin film with a thickness of 130 nm was fabricated on a silicon wafer using a RF magnetron sputtering process. The flexoelectric coefficients of the prepared thin films were determined experimentally. It was revealed that the thin films possessed a transverse flexoelectric coefficient of 24.5 μC/m at Curie temperature (∼28 °C) and 17.44 μC/m at 41 °C. The measured flexoelectric coefficients are comparable to that of bulk BST ceramics, which are reported to be 10–100 μC/m. This result suggests that the flexoelectric thin film structures can be effectively used for micro/nano-sensing devices.
International Nuclear Information System (INIS)
We use linear stability analysis and numerical solutions of partial differential equations to investigate pattern formation in the one-dimensional system of short dynamic polymers and one (plus-end directed) or two (one is plus-end, another minus-end directed) molecular motors. If polymer sliding and motor gliding rates are slow and/or the polymer turnover rate is fast, then the polymer-motor bundle has mixed polarity and homogeneous motor distribution. However, if motor gliding is fast, a sarcomeric pattern with periodic bands of alternating polymer polarity separated by motor aggregates evolves. On the other hand, if polymer sliding is fast, a graded-polarity bundle with motors at the center emerges. In the presence of the second, minus-end directed motor, the sarcomeric pattern is more ubiquitous, while the graded-polarity pattern is destabilized. However, if the minus-end motor is weaker than the plus-end directed one, and/or polymer nucleation is autocatalytic, and/or long polymers are present in the bundle, then a spindle-like architecture with a sorted-out polarity emerges with the plus-end motors at the center and minus-end motors at the edges. We discuss modeling implications for actin-myosin fibers and in vitro and meiotic spindles.
Fabrication and measurement of a flexoelectric micro-pyramid composite
Huang, Wenbin; Shu, Longlong; Ryung Kwon, Seol; Zhang, Shujun; Yuan, Fuh-Gwo; Jiang, Xiaoning
2014-12-01
A fabrication method by combining precision mechanical dicing and wet etching was developed to prepare micro-pyramid structures based on (Ba0.67Sr0.33)TiO3 ceramics. The effective piezoelectric properties of flexoelectric pyramid structures in ten micrometers scale were investigated and measured through converse flexoelectric effect. The scaling effect of the flexoelectric response was demonstrated as the structure size shrinks down. The results do suggest the great potential of flexoelectric micro pyramids as an alternative to lead-free piezoelectric material.
Study on a flexoelectric microphone using barium strontium titanate
Kwon, S. R.; Huang, W. B.; Zhang, S. J.; Yuan, F. G.; Jiang, X. N.
2016-04-01
In this study, a flexoelectric microphone was, for the first time, designed and fabricated in a bridge structure using barium strontium titanate (Ba0.65Sr0.35TiO3) ceramic and tested afterwards. The prototyped flexoelectric microphone consists of a 1.5 mm × 768 μm × 50 μm BST bridge structure and a silicon substrate with a cavity. The sensitivity and resonance frequency were designed to be 0.92 pC/Pa and 98.67 kHz, respectively. The signal to noise ratio was measured to be 74 dB. The results demonstrate that the flexoelectric microphone possesses high sensitivity and a wide working frequency range simultaneously, suggesting that flexoelectricity could be an excellent alternative sensing mechanism for microphone applications.
Computational evaluation of the flexoelectric effect in dielectric solids
Energy Technology Data Exchange (ETDEWEB)
Abdollahi, Amir; Peco, Christian; Millán, Daniel; Arroyo, Marino; Arias, Irene, E-mail: irene.arias@upc.edu [Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya (UPC), Campus Nord UPC-C2, E-08034 Barcelona (Spain)
2014-09-07
Flexoelectricity is a size-dependent electromechanical mechanism coupling polarization and strain gradient. It exists in a wide variety of materials, and is most noticeable for nanoscale objects, where strain gradients are higher. Simulations are important to understand flexoelectricity because experiments at very small scales are difficult, and analytical solutions are scarce. Here, we computationally evaluate the role of flexoelectricity in the electromechanical response of linear dielectric solids in two-dimensions. We deal with the higher-order coupled partial differential equations using smooth meshfree basis functions in a Galerkin method, which allows us to consider general geometries and boundary conditions. We focus on the most common setups to quantify the flexoelectric response, namely, bending of cantilever beams and compression of truncated pyramids, which are generally interpreted through approximate solutions. While these approximations capture the size-dependent flexoelectric electromechanical coupling, we show that they only provide order-of-magnitude estimates as compared with a solution fully accounting for the multidimensional nature of the problem. We discuss the flexoelectric mechanism behind the enhanced size-dependent elasticity in beam configurations. We show that this mechanism is also responsible for the actuation of beams under purely electrical loading, supporting the idea that a mechanical flexoelectric sensor also behaves as an actuator. The predicted actuation-induced curvature is in a good agreement with experimental results. The truncated pyramid configuration highlights the critical role of geometry and boundary conditions on the effective electromechanical response. Our results suggest that computer simulations can help understanding and quantifying the physical properties of flexoelectric devices.
First-principles theory and calculation of flexoelectricity
Hong, Jiawang; Vanderbilt, David
2013-01-01
We develop a general and unified first-principles theory of piezoelectric and flexoelectric tensor, formulated in such a way that the tensor elements can be computed directly in the context of density-functional calculations, including electronic and lattice contributions. We introduce a practical supercell-based methods for calculating the flexoelectric coefficients from first principles, and demonstrate them by computing the coefficients for a variety of cubic insulating materials, includin...
Computational evaluation of the flexoelectric effect in dielectric solids
Abdollahi, Amir; Peco, Christian; Millán, Daniel; Arroyo, Marino; Arias, Irene
2014-09-01
Flexoelectricity is a size-dependent electromechanical mechanism coupling polarization and strain gradient. It exists in a wide variety of materials, and is most noticeable for nanoscale objects, where strain gradients are higher. Simulations are important to understand flexoelectricity because experiments at very small scales are difficult, and analytical solutions are scarce. Here, we computationally evaluate the role of flexoelectricity in the electromechanical response of linear dielectric solids in two-dimensions. We deal with the higher-order coupled partial differential equations using smooth meshfree basis functions in a Galerkin method, which allows us to consider general geometries and boundary conditions. We focus on the most common setups to quantify the flexoelectric response, namely, bending of cantilever beams and compression of truncated pyramids, which are generally interpreted through approximate solutions. While these approximations capture the size-dependent flexoelectric electromechanical coupling, we show that they only provide order-of-magnitude estimates as compared with a solution fully accounting for the multidimensional nature of the problem. We discuss the flexoelectric mechanism behind the enhanced size-dependent elasticity in beam configurations. We show that this mechanism is also responsible for the actuation of beams under purely electrical loading, supporting the idea that a mechanical flexoelectric sensor also behaves as an actuator. The predicted actuation-induced curvature is in a good agreement with experimental results. The truncated pyramid configuration highlights the critical role of geometry and boundary conditions on the effective electromechanical response. Our results suggest that computer simulations can help understanding and quantifying the physical properties of flexoelectric devices.
Computational evaluation of the flexoelectric effect in dielectric solids
International Nuclear Information System (INIS)
Flexoelectricity is a size-dependent electromechanical mechanism coupling polarization and strain gradient. It exists in a wide variety of materials, and is most noticeable for nanoscale objects, where strain gradients are higher. Simulations are important to understand flexoelectricity because experiments at very small scales are difficult, and analytical solutions are scarce. Here, we computationally evaluate the role of flexoelectricity in the electromechanical response of linear dielectric solids in two-dimensions. We deal with the higher-order coupled partial differential equations using smooth meshfree basis functions in a Galerkin method, which allows us to consider general geometries and boundary conditions. We focus on the most common setups to quantify the flexoelectric response, namely, bending of cantilever beams and compression of truncated pyramids, which are generally interpreted through approximate solutions. While these approximations capture the size-dependent flexoelectric electromechanical coupling, we show that they only provide order-of-magnitude estimates as compared with a solution fully accounting for the multidimensional nature of the problem. We discuss the flexoelectric mechanism behind the enhanced size-dependent elasticity in beam configurations. We show that this mechanism is also responsible for the actuation of beams under purely electrical loading, supporting the idea that a mechanical flexoelectric sensor also behaves as an actuator. The predicted actuation-induced curvature is in a good agreement with experimental results. The truncated pyramid configuration highlights the critical role of geometry and boundary conditions on the effective electromechanical response. Our results suggest that computer simulations can help understanding and quantifying the physical properties of flexoelectric devices
Catalan, G; Sinnamon, LJ; Gregg, JM
2004-01-01
Recent experimental measurements of large flexoelectric coefficients in ferroelectric ceramics suggest that strain gradients can affect the polarization and permittivity behaviour of inhomogeneously strained ferroelectrics. Here we present a phenomenological model of the effect of flexoelectricity o
Analysis of smart nanobeams integrated with a flexoelectric nano actuator layer
Ray, M. C.
2016-05-01
This paper is concerned with the derivation of exact solutions for the static responses of simply supported nanobeams integrated with a flexoelectric layer acting as the distributed nano actuator. Considering both the direct and the converse flexoelectric effects, the governing equations and the associated boundary conditions of the overall beams are derived to obtain exact solutions for the displacements and the electric potential in the flexoelectric layer and the substrate beam. Due to the converse flexoelectric effect, the active flexoelectric layer significantly counteracts the deformations of the substrate beams caused by the applied mechanical load, resulting in the coupling of bending and stretching deformations in the substrate beams. For particular values of the length and thickness of the substrate beam and the applied voltage in the flexoelectric layer, the deflection of the substrate beam due to the converse flexoelectric effect increases with increasing thickness of the flexoelectric layer up to a certain value of the latter. Beyond this value, any further increase in the thickness of the flexoelectric layer causes a decrease in its ability to actuate the substrate beam. The electric potential varies linearly across the thickness of the flexoelectric layer. The benchmark results presented here may be useful for verifying further research and the present study suggests that the flexoelectric layer may be effectively exploited for advanced applications as a smart nano actuator.
A theory of flexoelectricity with surface effect for elastic dielectrics
Shen, Shengping; Hu, Shuling
2010-05-01
The flexoelectric effect is very strong for nanosized dielectrics. Moreover, on the nanoscale, surface effects and the electrostatic force cannot be ignored. In this paper, an electric enthalpy variational principle for nanosized dielectrics is proposed concerning with the flexoelectric effect, the surface effects and the electrostatic force. Here, the surface effects contain the effects of both surface stress and surface polarization. From this variational principle, the governing equations and the generalized electromechanical Young-Laplace equations are derived and can account for the effects of flexoelectricity, surface and the electrostatic force. Moreover, based on this variational principle, both the generalized bulk and surface electrostatic stresses can be obtained and are composed of two parts: the Maxwell stress corresponding to the polarization and strain and the remainder relating to the polarization gradient and the strain gradient. The theory developed in this paper provides the underlying framework for the analyses and computational solutions of electromechanical problems in nanodielectrics.
Giant flexoelectric polarization in a micromachined ferroelectric diaphragm
Wang, Zhihong
2012-08-14
The coupling between dielectric polarization and strain gradient, known as flexoelectricity, becomes significantly large on the micro- and nanoscale. Here, it is shown that giant flexoelectric polarization can reverse remnant ferroelectric polarization in a bent Pb(Zr0.52Ti0.48) O3 (PZT) diaphragm fabricated by micromachining. The polarization induced by the strain gradient and the switching behaviors of the polarization in response to an external electric field are investigated by observing the electromechanical coupling of the diaphragm. The method allows determination of the absolute zero polarization state in a PZT film, which is impossible using other existing methods. Based on the observation of the absolute zero polarization state and the assumption that bending of the diaphragm is the only source of the self-polarization, the upper bound of flexoelectric coefficient of PZT film is calculated to be as large as 2.0 × 10-4 C m -1. The strain gradient induced by bending the diaphragm is measured to be on the order of 102 m-1, three orders of magnitude larger than that obtained in the bulk material. Because of this large strain gradient, the estimated giant flexoelectric polarization in the bent diaphragm is on the same order of magnitude as the normal remnant ferroelectric polarization of PZT film. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Flexoelectric rotation of polarization in ferroelectric thin films
Catalan, G.; Lubk, A.; Vlooswijk, A. H. G.; Snoeck, E.; Magen, C.; Janssens, A.; Rispens, G.; Rijnders, G.; Blank, D. H. A.; Noheda, Beatriz
2011-01-01
Strain engineering enables modification of the properties of thin films using the stress from the substrates on which they are grown. Strain may be relaxed, however, and this can also modify the properties thanks to the coupling between strain gradient and polarization known as flexoelectricity. Her
Dielectric behavior of antiferroelectric liquid crystals in presence of flexoelectric effect
Energy Technology Data Exchange (ETDEWEB)
Das, Deblal; Mandal, Pravash; Majumder, Tapas Pal, E-mail: tpm@klyuniv.ac.in [Department of Physics, University of Kalyani, West Bengal (India)
2015-06-15
We studied theoretically the effect of flexoelectricity on the behavior of dielectric fluctuations of antiferroelectric liquid crystals (AFLCs) influenced by the mechanical distortion associated with flexoelectric effect. By using the appropriate free energy and the Landau-Ginzburg equation, we found an approximate expression of dielectric permittivity, which was strongly influenced by the existence of flexoelectric polarization for both in-phase and anti-phase motions. Consequently, the corresponding dielectric strength for both in-phase and anti-phase motions were varied due to the existence of flexoelectric polarization. (author)
Dielectric Behavior of Antiferroelectric Liquid Crystals in Presence of Flexoelectric Effect
Das, Deblal; Mandal, Pravash; Pal Majumder, Tapas
2015-06-01
We studied theoretically the effect of flexoelectricity on the behavior of dielectric fluctuations of antiferroelectric liquid crystals (AFLCs) influenced by the mechanical distortion associated with flexoelectric effect. By using the appropriate free energy and the Landau-Ginzburg equation, we found an approximate expression of dielectric permittivity, which was strongly influenced by the existence of flexoelectric polarization for both in-phase and anti-phase motions. Consequently, the corresponding dielectric strength for both in-phase and anti-phase motions were varied due to the existence of flexoelectric polarization.
The flexoelectric effect associated size dependent pyroelectricity in solid dielectrics
Energy Technology Data Exchange (ETDEWEB)
Bai, Gang, E-mail: baigang@njupt.edu.cn [Jiangsu Provincial Engineering Laboratory for RF Integration and Micropackaging and College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Liu, Zhiguo [Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Xie, Qiyun; Guo, Yanyan; Li, Wei [Jiangsu Provincial Engineering Laboratory for RF Integration and Micropackaging and College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Yan, Xiaobing [College of Electronic and information Engineering, Hebei University, Baoding 071002 (China)
2015-09-15
A phenomenological thermodynamic theory is used to investigate the effect of strain gradient on the pyroelectric effect in centrosymmetric dielectric solids. Direct pyroelectricity can exist as external mechanical stress is applied to non-pyroelectric dielectrics with shapes such as truncated pyramids, due to elastic strain gradient induced flexoelectric polarization. Effective pyroelectric coefficient was analyzed in truncated pyramids. It is found to be controlled by size, ambient temperature, stress, and aspect ratio and depends mainly on temperature sensitivity of flexoelectric coefficient (TSFC) and strain gradient of the truncated pyramids dielectric solids. These results show that the pyroelectric property of Ba{sub 0.67}Sr{sub 0.33}TiO{sub 3} above T{sub c} similar to PZT and other lead-based ferroelectrics can be obtained. This feature might widely broaden the selection of materials for infrared detectors with preferable properties.
The flexoelectric effect associated size dependent pyroelectricity in solid dielectrics
International Nuclear Information System (INIS)
A phenomenological thermodynamic theory is used to investigate the effect of strain gradient on the pyroelectric effect in centrosymmetric dielectric solids. Direct pyroelectricity can exist as external mechanical stress is applied to non-pyroelectric dielectrics with shapes such as truncated pyramids, due to elastic strain gradient induced flexoelectric polarization. Effective pyroelectric coefficient was analyzed in truncated pyramids. It is found to be controlled by size, ambient temperature, stress, and aspect ratio and depends mainly on temperature sensitivity of flexoelectric coefficient (TSFC) and strain gradient of the truncated pyramids dielectric solids. These results show that the pyroelectric property of Ba0.67Sr0.33TiO3 above Tc similar to PZT and other lead-based ferroelectrics can be obtained. This feature might widely broaden the selection of materials for infrared detectors with preferable properties
Revisiting pyramid compression to quantify flexoelectricity: A three-dimensional simulation study
Abdollahi, Amir; Millán, Daniel; Peco, Christian; Arroyo, Marino; Arias, Irene
2015-03-01
Flexoelectricity is a universal property of all dielectrics by which they generate a voltage in response to an inhomogeneous deformation. One of the controversial issues in this field concerns the magnitude of flexoelectric coefficients measured experimentally, which greatly exceed theoretical estimates. Furthermore, there is a broad scatter amongst experimental measurements. The truncated pyramid compression method is one of the common setups to quantify flexoelectricity, the interpretation of which relies on simplified analytical equations to estimate strain gradients. However, the deformation fields in three-dimensional pyramid configurations are highly complex, particularly around its edges. In the present work, using three-dimensional self-consistent simulations of flexoelectricity, we show that the simplified analytical estimations of strain gradients in compressed pyramids significantly overestimate flexoelectric coefficients, thus providing a possible explanation to reconcile different estimates. In fact, the interpretation of pyramid compression experiments is highly nontrivial. We systematically characterize the magnitude of this overestimation, of over one order of magnitude, as a function of the truncated pyramid configuration. These results are important to properly characterize flexoelectricity, and provide design guidelines for effective electromechanical transducers exploiting flexoelectricity.
Flexoelectric piezoelectric metamaterials based on the bending of ferroelectric ceramic wafers
Zhang, Xiaotong; Liu, Jiliang; Chu, Mingjin; Chu, Baojin
2016-08-01
Conventional piezoelectric ceramics lose their piezoelectric properties near the Curie temperature (Tc), which limits their application at high temperatures. One approach to resolving this issue is to design flexoelectric piezoelectric composites or piezoelectric metamaterials by exploiting the flexoelectric effect of the ferroelectric materials. In this work, an experimental study on two designs of flexoelectric metamaterials is demonstrated. When a ferroelectric ceramic wafer is placed on a metal ring or has a domed shape, which is produced through the diffusion between two pieces of ferroelectric ceramic of different compositions at high temperatures, an apparent piezoelectric response originating from the flexoelectric effect can be measured under a stress. The apparent piezoelectric response of the materials based on the designs can be sustained well above Tc. This study provides an approach to designing materials for high-temperature electromechanical applications.
Flexoelectricity and the polarity of complex ferroelastic twin patterns
Salje, Ekhard K. H.; Li, Suzhi; Stengel, Massimiliano; Gumbsch, Peter; Ding, Xiangdong
2016-07-01
We study, by means of an atomistic toy model, the interplay of ferroelastic twin patterns and electrical polarization. Our molecular dynamics simulations reproduce polarity in straight twin walls as observed experimentally. We show, by making contact with continuum theory, that the effect is governed by linear flexoelectricity. Complex twin patterns, with very high densities of kinks and/or junctions, produce winding structures in the dipolar field, which are reminiscent of polarization vortices. By means of a "cold shearing" technique, we produce patches with high vortex densities; these unexpectedly show a net macroscopic polarization even if neither the original sample nor the applied mechanical perturbation breaks inversion symmetry by itself. These results may explain some puzzling experimental observations of "parasitic" polarity in the paraelectric phase of BaTi O3 and LaAl O3 .
Strong surface effect on direct bulk flexoelectric response in solids
Energy Technology Data Exchange (ETDEWEB)
Yurkov, A. S. [Ioffe Physical-Technical Institute, 26 Politekhnicheskaya, 194021 St. Petersburg (Russian Federation); Tagantsev, A. K. [Ceramics Laboratory, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne (Switzerland); Ioffe Physical-Technical Institute, 26 Politekhnicheskaya, 194021 St. Petersburg (Russian Federation)
2016-01-11
In the framework of a continuum theory, it is shown that the direct bulk flexoelectric response of a finite sample essentially depends on the surface polarization energy, even in the thermodynamic limit where the body size tends to infinity. It is found that a modification of the surface energy can lead to a change in the polarization response by a factor of two. The origin of the effect is an electric field produced by surface dipoles induced by the strain gradient. The unexpected sensitivity of the polarization response to the surface energy in the thermodynamic limit is conditioned by the fact that the moments of the surface dipoles may scale as the body size.
Heal, Geoffrey
2002-01-01
Biodiversity provides essential services to human societies. Many of these services are provided as public goods, so that they will typically be underprovided both by market mechanisms (because of the impossibility of excluding non-payers from using the services) and by government-run systems (because of the free rider problem). I suggest here that in some cases the public goods provided by biodiversity conservation can be bundled with private goods and their value to consumers captured in th...
Thermal gradient induced flexoelectric effects in bulk Ba0.67Sr0.33TiO3
Kim, Taeyang; Huang, Wenbin; Huang, Shujin; Jiang, Xiaoning
2016-05-01
Flexoelectric effect, denoting electric field gradient induced mechanical strain or mechanical strain gradient induced electric polarization, is a universal phenomenon in all dielectrics. Although research on the topic of flexoelectricity under stress fields and electric fields has advanced significantly, information regarding the phenomenon under thermal fields is rather limited. In this letter, the flexoelectricity field of Ba0.67Sr0.33TiO3 (BST) was investigated by generating temperature gradients along the lengths of samples with symmetric geometry. An electric field gradient induced by a thermal gradient was analyzed based on the temperature-dependent dielectric property of BST. The strain was then experimentally verified due to the electric field gradient. Experimental results suggest converse flexoelectric effect of BST samples with symmetric geometry in a thermal field. This result was not only consistent with the theoretical prediction, but it also followed the scaling effect of flexoelectricity.
Zhang, Zhiqiang; Geng, Dalong; Wang, Xudong
2016-04-01
A simple and effective decoupled finite element analysis method was developed for simulating both the piezoelectric and flexoelectric effects of zinc oxide (ZnO) and barium titanate (BTO) nanowires (NWs). The piezoelectric potential distribution on a ZnO NW was calculated under three deformation conditions (cantilever, three-point, and four-point bending) and compared to the conventional fully coupled method. The discrepancies of the electric potential maximums from these two methods were found very small, validating the accuracy and effectiveness of the decoupled method. Both ZnO and BTO NWs yielded very similar potential distributions. Comparing the potential distributions induced by the piezoelectric and flexoelectric effects, we identified that the middle segment of a four-point bending NW beam is the ideal place for measuring the flexoelectric coefficient, because the uniform parallel plate capacitor-like potential distribution in this region is exclusively induced by the flexoelectric effect. This decoupled method could provide a valuable guideline for experimental measurements of the piezoelectric effects and flexoelectric effects in the nanometer scale.
Kancharala, Ashok; Freeman, Eric; Philen, Michael
2016-10-01
Droplet interface bilayers have found applications in the development of biologically-inspired mechanosensors. In this research, a comprehensive flexoelectric framework has been developed to predict the mechanoelectric capabilities of the biological membrane under mechanical excitation for sensing and energy harvesting applications. The dynamic behavior of the droplets has been modeled using nonlinear finite element analysis, coupled with a flexoelectric model for predicting the resulting material polarization. This coupled model allows for the prediction of the mechanoelectrical response of the droplets under excitation. Using the developed framework, the potential for sensing and energy harvesting through lipid membranes is investigated.
Requirements for disordered actomyosin bundle contractility
Lenz, Martin
2011-01-01
Actomyosin contractility is essential for biological force generation, and is well understood in highly ordered structures such as striated muscle. In vitro experiments have shown that non-sarcomeric bundles comprised only of F-actin and myosin thick filaments can also display contractile behavior, which cannot be described by standard muscle models. Here we investigate the microscopic symmetries underlying this process in large non-sarcomeric bundles with long actin filaments. We prove that contractile behavior requires non-identical motors that generate large enough forces to probe the nonlinear elastic behavior of F-actin. A simple disordered bundle model demonstrates a contraction mechanism based on these assumptions and predicts realistic bundle deformations. Recent experimental observations of F-actin buckling in in vitro contractile bundles support our model.
International Nuclear Information System (INIS)
The increase of bundle supply has become widespread in several sectors (for instance in telecommunications and energy fields). This paper review relates strategic aspects of bundling. The main purpose of this paper is to analyze profitability of bundling strategies according to the degree of competition and the characteristics of goods. Moreover, bundling can be used as price discrimination tool, screening device or entry barriers. In monopoly case bundling strategy is efficient to sort consumers in different categories in order to capture a maximum of surplus. However, when competition increases, the profitability on bundling strategies depends on correlation of consumers' reservations values. (author)
Experimental Investigations of Direct and Converse Flexoelectric Effect in Bilayer Lipid Membranes.
Todorov, Angelio Todorov
Flexoelectric coefficients (direct and converse), electric properties (capacitance and resistivity) and mechanical properties (thickness and elastic coefficients) have been determined for bilayer lipid membranes (BLMs) prepared from egg yolk lecithin (EYL), glycerol monoleate (GMO), phosphatidyl choline (PC) and phosphatidyl serine (PS) as a function of frequency, pH and surface charge modifiers. Direct flexoelectric effect manifested itself in the development of microvolt range a.c. potential (U_{f}) upon subjecting one side of a BLM to an oscillating hydrostatic pressure, in the 100-1000 Hz range. Operationally, the flexoelectric coefficient (f) is expressed by the ratio between U_{f} and the change of curvature (c) which accompanied the flexing of the membrane. Membrane curvature was determined by means of either the electric method (capacitance microphone effect) or by the newly developed method of stroboscopic interferometry. Real-time stroboscopic interferometry coupled with simultaneous electric measurements, provided a direct method for the determination of f. Two different frequency regimes of f were recognized. At low frequencies (GMO BLMs. At high frequencies (>300 Hz), associated with blocked mobility of the surfactant, f-values of 16.5 times 10^ {-19} and 0.30 times 10^{-19} Coulombs were obtained for PC and GMO BLMs. The theoretically calculated value for the GMO BLM oscillating at high frequency (0.12 times 10^{-19 } Coulombs) agreed well with that determined experimentally (0.3 times 10 ^{-19} Coulombs). For charged bovine brain PS BLM the observed flexocoefficient was f = 4.0 times 10^{ -18} Coulombs. Converse flexoelectric effect manifested itself in voltage-induced BLM curvature. Observations were carried out on uranyl acetate (UA) stabilized PS BLM under a.c. excitation. Frequency dependence of f was revealed by means of real-time stroboscopic interferometry. Satisfactory agreement was observed between the direct and converse f-values, measured
Bundling in Telecommunications
Begoña García-Mariñoso; Xavier Martinez-Giralt; Pau Olivella
2008-01-01
The paper offers an overview of the literature on bundling in the telecommunications sector and its application in the Spanish market. We argue that the use of bundling in the provision of services is associated to technological reasons. Therefore, there appears no need to regulate bundling activities. However, this is not to say that other related telecom markets should not be scrutinized and regulated, or that the regulator should not pay attention to other bundling-related anticompetitive ...
Unified ab initio formulation of flexoelectricity and strain-gradient elasticity
Stengel, Massimiliano
2016-06-01
The theory of flexoelectricity and that of nonlocal elasticity are closely related, and are often considered together when modeling strain-gradient effects in solids. Here I show, based on a first-principles lattice-dynamical analysis, that their relationship is much more intimate than previously thought, and their consistent simultaneous treatment is crucial for obtaining correct physical answers. In particular, I identify a gauge invariance in the theory, whereby the energies associated to strain-gradient elasticity and flexoelectrically induced electric fields are individually reference dependent, and only when summed up they yield a well-defined result. To illustrate this, I construct a minimal thermodynamic functional incorporating strain-gradient effects, and establish a formal link between the continuum description and ab initio phonon dispersion curves to calculate the relevant tensor quantities. As a practical demonstration, I apply such a formalism to bulk SrTiO3, where I find an unusually strong contribution of nonlocal elasticity, mediated by the interaction between the ferroelectric soft mode and the transverse acoustic branches. These results have important implications towards the construction of well-defined thermodynamic theories where flexoelectricity and ferroelectricity coexist. More generally, they open exciting new avenues for the implementation of hierarchical multiscale concepts in the first-principles simulation of crystalline insulators.
Biswas, Indranil
2011-01-01
We construct projectivization of a parabolic vector bundle and a tautological line bundle over it. It is shown that a parabolic vector bundle is ample if and only if the tautological line bundle is ample. This allows us to generalize the notion of a k-ample bundle, introduced by Sommese, to the context of parabolic bundles. A parabolic vector bundle $E_*$ is defined to be k-ample if the tautological line bundle ${\\mathcal O}_{{\\mathbb P}(E_*)}(1)$ is $k$--ample. We establish some properties of parabolic k-ample bundles.
Lerman, Eugene
2003-01-01
We define contact fiber bundles and investigate conditions for the existence of contact structures on the total space of such a bundle. The results are analogous to minimal coupling in symplectic geometry. The two applications are construction of K-contact manifolds generalizing Yamazaki's fiber join construction and a cross-section theorem for contact moment maps
Principal noncommutative torus bundles
DEFF Research Database (Denmark)
Echterhoff, Siegfried; Nest, Ryszard; Oyono-Oyono, Herve
2008-01-01
action) and give necessary and sufficient conditions for any non-commutative principal torus bundle being RKK-equivalent to a commutative one. As an application of our methods we shall also give a K-theoretic characterization of those principal torus-bundles with H-flux, as studied by Mathai...... and Rosenberg which possess "classical" T-duals....
Yu, Pengfei; Hu, Shuling; Shen, Shengping
2016-08-01
Recently, a new scanning probe microscopy approach, referred to as electrochemical strain microscopy (ESM), for probing local ionic flows and electrochemical reactions in solids based on the bias-strain coupling was proposed by Morozovska et al. Then, a series of theoretical papers for analyzing the image formation and spectroscopic mechanism of ESM were published within the framework of Fermi-Dirac statistics, the Vegard law, the direct flexoelectric coupling effect, the electrostriction effect, and so on. However, most of the models in these papers are limited to the partial coupling or particular process, and numerically solved by using decoupling approximation. In this paper, to model the ESM measurement with the coupling electrical-chemical-mechanical process, the chemical Gibbs function variational principle for the thermal electrical chemical mechanical fully coupling problem is proposed. The fully coupling governing equations are derived from the variational principle. When the tip concentrates the electric field within a small volume of the material, the inhomogeneous electric field is induced. So, both direct and inverse flexoelectric effects should be taken into account. Here, the bulk defect electrochemical reactions are also taken into account, which are usually omitted in the existing works. This theory can be used to deal with coupling problems in solids, including conductors, semiconductors, and piezoelectric and non-piezoelectric dielectrics. As an application of this work, a developed initial-boundary value problem is solved numerically in a mixed ion-electronic conductor. Numerical results show that it is meaningful and necessary to consider the bulk defect chemical reaction. Besides, the chemical reaction and the flexoelectric effect have an interactive influence on each other. This work can provide theoretical basis for the ESM as well as investigating the bulk chemical reaction process in solids.
Flexoelectric coefficient measurements in the nematic liquid crystal phase of 5CB
Directory of Open Access Journals (Sweden)
F. Castles
2012-06-01
Full Text Available We report measurements of the bulk flexoelectric coefficient (e1 − e3 of 5CB (4-Cyano-4′-pentylbiphenyl, in the temperature range 20–34 °C, with a relative combined standard uncertainty of 2 %. The chiral flexoelectro-optic method was used with 1 wt % high-twisting-power chiral additive. At 25 °C, (e1 − e3 = 7.10 pC/m with a combined standard uncertainty of 0.14 pC/m.
Restrictions of stable bundles
Balaji, V
2011-01-01
The Mehta-Ramanathan theorem ensures that the restriction of a stable vector bundle to a sufficiently high degree complete intersection curve is again stable. We improve the bounds for the "sufficiently high degree" and propose a possibly optimal conjecture.
Han, Jin Kyu; Jeon, Do Hyun; Cho, Sam Yeon; Kang, Sin Wook; Yang, Sun A.; Bu, Sang Don; Myung, Sung; Lim, Jongsun; Choi, Moonkang; Lee, Minbaek; Lee, Min Ku
2016-07-01
We report the first attempt to prepare a flexoelectric nanogenerator consisting of direct-grown piezoelectrics on multi-walled carbon nanotubes (mwCNT). Direct-grown piezoelectrics on mwCNTs are formed by a stirring and heating method using a Pb(Zr0.52Ti0.48)O3 (PZT)-mwCNT precursor solution. We studied the unit cell mismatch and strain distribution of epitaxial PZT nanoparticles, and found that lattice strain is relaxed along the growth direction. A PZT-mwCNT nanogenerator was found to produce a peak output voltage of 8.6 V and an output current of 47 nA when a force of 20 N is applied. Direct-grown piezoelectric nanogenerators generate a higher voltage and current than simple mixtures of PZT and CNTs resulting from the stronger connection between PZT crystals and mwCNTs and an enhanced flexoelectric effect caused by the strain gradient. These experiments represent a significant step toward the application of nanogenerators using piezoelectric nanocomposite materials.
Gui-Li, Zheng; Hui, Zhang; Wen-Jiang, Ye; Zhi-Dong, Zhang; Hong-Wei, Song; Li, Xuan
2016-03-01
Based on the experimental phenomena of flexoelectric response at defect sites in nematic inversion walls conducted by Kumar et al., we gave the theoretical analysis using the Frank elastic theory. When a direct-current electric field normal to the plane of the substrate is applied to the parallel aligned nematic liquid crystal cell with weak anchoring, the rotation of ±1 defects in the narrow inversion walls can be exhibited. The free energy of liquid crystal molecules around the +1 and -1 defect sites in the nematic inversion walls under the electric field was formulated and the electric-field-driven structural changes at the defect site characterized by polar and azimuthal angles of the local director were simulated. The results reveal that the deviation of azimuthal angle induced by flexoelectric effect are consistent with the switching of extinction brushes at the +1 and -1 defects obtained in the experiment conducted by Kumar et al. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374087, 11274088, and 11304074), the Natural Science Foundation of Hebei Province, China (Grant Nos. A2014202123 and A2016202282), the Research Project of Hebei Education Department, China (Grant Nos. QN2014130 and QN2015260), and the Key Subject Construction Project of Hebei Province University, China.
Subtleties Concerning Conformal Tractor Bundles
Graham, C Robin
2012-01-01
The realization of tractor bundles as associated bundles in conformal geometry is studied. It is shown that different natural choices of principal bundle with normal Cartan connection corresponding to a given conformal manifold can give rise to topologically distinct associated tractor bundles for the same inducing representation. Consequences for homogeneous models and conformal holonomy are described. A careful presentation is made of background material concerning standard tractor bundles and equivalence between parabolic geometries and underlying structures.
DEFF Research Database (Denmark)
Bussink, Barbara E; Holst, Anders Gaarsdal; Jespersen, Lasse;
2013-01-01
AimsTo determine the prevalence, predictors of newly acquired, and the prognostic value of right bundle branch block (RBBB) and incomplete RBBB (IRBBB) on a resting 12-lead electrocardiogram in men and women from the general population.Methods and resultsWe followed 18 441 participants included.......5%/2.3% in women, P Right bundle branch block was associated with significantly...... increased all-cause and cardiovascular mortality in both genders with age-adjusted hazard ratios (HR) of 1.31 [95% confidence interval (CI), 1.11-1.54] and 1.87 (95% CI, 1.48-2.36) in the gender pooled analysis with little attenuation after multiple adjustment. Right bundle branch block was associated...
Principal -bundles on Nodal Curves
Indian Academy of Sciences (India)
Usha N Bhosle
2001-08-01
Let be a connected semisimple affine algebraic group defined over . We study the relation between stable, semistable -bundles on a nodal curve and representations of the fundamental group of . This study is done by extending the notion of (generalized) parabolic vector bundles to principal -bundles on the desingularization of and using the correspondence between them and principal -bundles on . We give an isomorphism of the stack of generalized parabolic bundles on with a quotient stack associated to loop groups. We show that if is simple and simply connected then the Picard group of the stack of principal -bundles on is isomorphic to ⊕ , being the number of components of .
Directory of Open Access Journals (Sweden)
J. W. Kitchen
1994-01-01
Full Text Available We study bundles of Banach algebras π:A→X, where each fiber Ax=π−1({x} is a Banach algebra and X is a compact Hausdorff space. In the case where all fibers are commutative, we investigate how the Gelfand representation of the section space algebra Γ(π relates to the Gelfand representation of the fibers. In the general case, we investigate how adjoining an identity to the bundle π:A→X relates to the standard adjunction of identities to the fibers.
On projective space bundle with nef normalized tautological line bundle
Yasutake, Kazunori
2011-01-01
In this paper, we study the structure of projective space bundles whose relative anti-canonical line bundle is nef. As an application, we get a characterization of abelian varieties up to finite etale covering.
Institute of Scientific and Technical Information of China (English)
关荣华; 叶文江; 邢红玉
2015-01-01
The physical effects on surface and flexoelectric polarization in a weak anchoring nematic liquid crystal cell are investigated systematically. We derive the analytic expressions of two effective anchoring energies for lower and upper substrates respectively as well as their effective anchoring strengths and corresponding tilt angles of effective easy direction. All of these quantities are relevant to the magnitudes of both two polarizations and the applied voltage U . Based on these expressions, the variations of effective anchoring strength and the tilt angle with the applied voltage are calculated for the fixed values of two polarizations. For an original weak anchoring hybrid aligned nematic cell, it may be equivalent to a planar cell for a small value of U and has a threshold voltage. The variation of reduced threshold voltage with reduced surface polarization strength is also calculated. The role of surface polarization is important without the adsorptive ions considered.
Energy Minimization for Liquid Crystal Equilibrium with Electric and Flexoelectric Effects
Adler, J H; Benson, T R; Emerson, D B; MacLachlan, S P
2014-01-01
This paper outlines an energy-minimization finite-element approach to the modeling of equilibrium configurations for nematic liquid crystals in the presence of internal and external electric fields. The method targets minimization of system free energy based on the electrically and flexoelectrically augmented Frank-Oseen free energy models. The Hessian, resulting from the linearization of the first-order optimality conditions, is shown to be invertible for both models when discretized by a mixed finite-element method under certain assumptions. This implies that the intermediate discrete linearizations are well-posed. A coupled multigrid solver with Vanka-type relaxation is proposed and numerically vetted for approximation of the solution to the linear systems arising in the linearizations. Two electric model numerical experiments are performed with the proposed iterative solver. The first compares the algorithm's solution of a classical Freedericksz transition problem to the known analytical solution and demo...
Variational principles and governing equations in nano-dielectrics with the flexoelectric effect
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The flexoelectric effect is very strong and coupled with large strain gradients for nanoscale dielectrics. At the nanoscale, the electrostatic force cannot be ignored. In this paper, we have established the electric enthalpy variational principle for nanosized dielectrics with the strain gradient and the polarization gradient effect, as well as the effect of the electrostatic force. The complete governing equations, which include the effect of the electrostatic force, are derived from this variational principle, and based on the principle the generalized electrostatic stress is obtained, the generalized electrostatic stress contains the Maxwell stress corresponding to the polarization and strain, and stress related to the polarization gradient and strain gradient. This work provides the basis for the analysis and computations for the electromechanical problems in nanosized dielectric materials.
International Nuclear Information System (INIS)
A hybrid bundle divertor design is presented that produces <0.3% magnetic ripple at the center of the plasma while providing adequate space for the coil shielding and structure for a tokamak fusion test reactor similar to the International Tokamak Reactor and the Engineering Test Facility (with R = 5 m, B = 5 T, and a /SUB wall/ = 1.5 m, in particular). This hybrid divertor consists of a set of quadrupole ''wing'' coils running tangent to the tokamak plasma on either side of a bundle divertor. The wing coils by themselves pull the edge of the plasma out 1.5 m and spread the thickness of the scrape-off layer from 0.1 to 0.7 m at the midplane. The clear aperture of the bundle divertor throat is 1.0 m high and 1.8 m wide. For maintenance or replacement, the hybrid divertor can be disassembled into three parts, with the bundle divertor part pulling straight out between toroidal field coils and the wing coils then sliding out through the same opening
Directory of Open Access Journals (Sweden)
Iosif DUMITRESCU
2015-05-01
Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.
Sepe, D.
2013-01-01
The obstruction to construct a Lagrangian bundle over a fixed integral affine manifold was constructed by Dazord and Delzant (J Differ Geom 26:223–251, 1987) and shown to be given by ‘twisted’ cup products in Sepe (Differ GeomAppl 29(6): 787–800, 2011). This paper uses the topology of universal Lagr
On framed quantum principal bundles
Durdevic, M
1995-01-01
A noncommutative-geometric formalism of framed principal bundles is sketched, in a special case of quantum bundles (over quantum spaces) possessing classical structure groups. Quantum counterparts of torsion operators and Levi-Civita type connections are analyzed. A construction of a natural differential calculus on framed bundles is described. Illustrative examples are presented.
Deformation quantization of principal bundles
Aschieri, Paolo
2016-01-01
We outline how Drinfeld twist deformation techniques can be applied to the deformation quantization of principal bundles into noncommutative principal bundles, and more in general to the deformation of Hopf-Galois extensions. First we twist deform the structure group in a quantum group, and this leads to a deformation of the fibers of the principal bundle. Next we twist deform a subgroup of the group of authomorphisms of the principal bundle, and this leads to a noncommutative base space. Considering both deformations we obtain noncommutative principal bundles with noncommutative fiber and base space as well.
Contractile units in disordered actomyosin bundles arise from F-actin buckling
Lenz, Martin; Gardel, Margaret L; Dinner, Aaron R
2012-01-01
Bundles of filaments and motors are central to contractility in cells. The classic example is striated muscle, where actomyosin contractility is mediated by highly organized sarcomeres which act as fundamental contractile units. However, many contractile bundles in vivo and in vitro lack sarcomeric organization. Here we propose a model for how contractility can arise in actomyosin bundles without sarcomeric organization and validate its predictions with experiments on a reconstituted system. In the model, internal stresses in frustrated arrangements of motors with diverse velocities cause filaments to buckle, leading to overall shortening. We describe the onset of buckling in the presence of stochastic actin-myosin detachment and predict that buckling-induced contraction occurs in an intermediate range of motor densities. We then calculate the size of the "contractile units" associated with this process. Consistent with these results, our reconstituted actomyosin bundles contract at relatively high motor dens...
Rudakov, A N
1990-01-01
This volume is devoted to the use of helices as a method for studying exceptional vector bundles, an important and natural concept in algebraic geometry. The work arises out of a series of seminars organised in Moscow by A. N. Rudakov. The first article sets up the general machinery, and later ones explore its use in various contexts. As to be expected, the approach is concrete; the theory is considered for quadrics, ruled surfaces, K3 surfaces and P3(C).
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.
Bundling harvester; Nippukorjausharvesteri
Energy Technology Data Exchange (ETDEWEB)
Koponen, K. [Eko-Log Oy, Kuopio (Finland)
1996-12-31
The staring point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automatizing of the harvester, and automatized loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilization of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilized without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilization of wood-energy
Draper, Andrew
2011-04-01
Results of Medicare's ACE demonstration project and Geisinger Health System's ProvenCare initiative provide insight into the challenges hospitals will face as bundled payment proliferates. An early analysis of these results suggests that hospitals would benefit from bringing full automation using clinical IT tools to bear in their efforts to meet these challenges. Other important factors contributing to success include board and physician leadership, organizational structure, pricing methodology for bidding, evidence-based medical practice guidelines, supply cost management, process efficiency management, proactive and aggressive case management, business development and marketing strategy, and the financial management system.
Draper, Andrew
2011-04-01
Results of Medicare's ACE demonstration project and Geisinger Health System's ProvenCare initiative provide insight into the challenges hospitals will face as bundled payment proliferates. An early analysis of these results suggests that hospitals would benefit from bringing full automation using clinical IT tools to bear in their efforts to meet these challenges. Other important factors contributing to success include board and physician leadership, organizational structure, pricing methodology for bidding, evidence-based medical practice guidelines, supply cost management, process efficiency management, proactive and aggressive case management, business development and marketing strategy, and the financial management system. PMID:21548437
Cassou-Nogues, Ph.; Erez, B.; Taylor, M. J.
2004-01-01
We establish comparison results between the Hasse-Witt invariants w_t(E) of a symmetric bundle E over a scheme and the invariants of one of its twists E_{\\alpha}. For general twists we describe the difference between w_t(E) and w_t(E_{\\alpha}) up to terms of degree 3. Next we consider a special kind of twist, which has been studied by A. Fr\\"ohlich. This arises from twisting by a cocycle obtained from an orthogonal representation. We show how to explicitly describe the twist for representatio...
Differential calculi on noncommutative bundles
Pflaum, Markus J.; Schauenburg, Peter
1996-01-01
We introduce a category of noncommutative bundles. To establish geometry in this category we construct suitable noncommutative differential calculi on these bundles and study their basic properties. Furthermore we define the notion of a connection with respect to a differential calculus and consider questions of existence and uniqueness. At the end these constructions are applied to basic examples of noncommutative bundles over a coquasitriangular Hopf algebra.
International Nuclear Information System (INIS)
This report is a summary of experimental investigations describing the fuel rod behavior in the refilling and reflooding phase of a loss-of-coolant accident of a PWR. The experiments were performed with 5x5 and 7x7 rod bundles, using indirectly electrically heated fuel rod simulators of full length with original PWR-KWU-geometry, original grid spacers and Zircaloy-4-claddings (Type Biblis B). The fuel rod simulators showed a cosine shaped axial power profile in 7 steps and continuous, respectively. The results describe the influence of the different parameters such as bundle size on the maximum coolant channel blockage, that of the cooling on the size of the circumferential strain of the cladding (azimuthal temperature distribution) a cold control rod guide thimble and the flow direction (axial temperature distribution) on the resulting coolant channel blockage. The rewetting behavior of different fuel rod simulators including ballooned and burst Zircaloy claddings is discussed as well as the influence of thermocouples on the cladding temperature history and the rewetting behavior. All results prove the coolability of a PWR in the case of a LOCA. Therefore, it can be concluded that the ECC-criteria established by licensing authorities can be fulfilled. (orig./HP)
Fiber Bundles and Parseval Frames
Agrawal, Devanshu; Knisley, Jeff
2015-01-01
Continuous frames over a Hilbert space have a rich and sophisticated structure that can be represented in the form of a fiber bundle. The fiber bundle structure reveals the central importance of Parseval frames and the extent to which Parseval frames generalize the notion of an orthonormal basis.
Bundle Security Protocol for ION
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.
Twisted Vector Bundles on Pointed Nodal Curves
Indian Academy of Sciences (India)
Ivan Kausz
2005-05-01
Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich’s and Vistoli’s twisted bundles and Gieseker vector bundles.
Semiflexible Biopolymers in Bundled Arrangements
Directory of Open Access Journals (Sweden)
Jörg Schnauß
2016-07-01
Full Text Available Bundles and networks of semiflexible biopolymers are key elements in cells, lending them mechanical integrity while also enabling dynamic functions. Networks have been the subject of many studies, revealing a variety of fundamental characteristics often determined via bulk measurements. Although bundles are equally important in biological systems, they have garnered much less scientific attention since they have to be probed on the mesoscopic scale. Here, we review theoretical as well as experimental approaches, which mainly employ the naturally occurring biopolymer actin, to highlight the principles behind these structures on the single bundle level.
The Atiyah Bundle and Connections on a Principal Bundle
Indian Academy of Sciences (India)
Indranil Biswas
2010-06-01
Let be a ∞ manifold and a Lie a group. Let $E_G$ be a ∞ principal -bundle over . There is a fiber bundle $\\mathcal{C}(E_G)$ over whose smooth sections correspond to the connections on $E_G$. The pull back of $E_G$ to $\\mathcal{C}(E_G)$ has a tautological connection. We investigate the curvature of this tautological connection.
Variable recruitment in bundles of miniature pneumatic artificial muscles.
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
Bundling ecosystem services in Denmark
DEFF Research Database (Denmark)
Turner, Katrine Grace; Odgaard, Mette Vestergaard; Bøcher, Peder Klith;
2014-01-01
We made a spatial analysis of 11 ecosystem services at a 10 km × 10 km grid scale covering most of Denmark. Our objective was to describe their spatial distribution and interactions and also to analyze whether they formed specific bundle types on a regional scale in the Danish cultural landscape....... We found clustered distribution patterns of ecosystem services across the country. There was a significant tendency for trade-offs between on the one hand cultural and regulating services and on the other provisioning services, and we also found the potential of regulating and cultural services...... to form synergies. We identified six distinct ecosystem service bundle types, indicating multiple interactions at a landscape level. The bundle types showed specialized areas of agricultural production, high provision of cultural services at the coasts, multifunctional mixed-use bundle types around urban...
DEFF Research Database (Denmark)
Risum, Niels; Strauss, David; Sogaard, Peter;
2013-01-01
The relationship between myocardial electrical activation by electrocardiogram (ECG) and mechanical contraction by echocardiography in left bundle-branch block (LBBB) has never been clearly demonstrated. New strict criteria for LBBB based on a fundamental understanding of physiology have recently...
Kun, Ferenc; Zapperi, Stefano; Herrmann, Hans J.
1999-01-01
We introduce a continuous damage fiber bundle model that gives rise to macroscopic plasticity and compare its behavior with that of dry fiber bundles. Several interesting constitutive behaviors are found in this model depending on the value of the damage parameter and on the form of the disorder distribution. In addition, we compare the behavior of global load transfer models with local load transfer models and study in detail the damage evolution before failure. We emphasize the analogies be...
Cohomology of line bundles: Applications
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.
Bundle Formation in Biomimetic Hydrogels.
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.
Principal bundles the classical case
Sontz, Stephen Bruce
2015-01-01
This introductory graduate level text provides a relatively quick path to a special topic in classical differential geometry: principal bundles. While the topic of principal bundles in differential geometry has become classic, even standard, material in the modern graduate mathematics curriculum, the unique approach taken in this text presents the material in a way that is intuitive for both students of mathematics and of physics. The goal of this book is to present important, modern geometric ideas in a form readily accessible to students and researchers in both the physics and mathematics communities, providing each with an understanding and appreciation of the language and ideas of the other.
Zheng, Guili; Zhang, Hui; Ye, Wenjiang; Zhang, Zhidong; Song, Hong-wei; Xuan, Li
2016-02-01
Fully leaky optical-guided mode was employed to determine the difference in the splay and bend flexoelectric coefficient (e1-e3) in negative nematic liquid crystal MS-N01300-000. The experimental curves of reflectivity versus internal angle (angle of incident light to the liquid crystal) were obtained when a laser beam passed through the hybrid-aligned nematic in-plane switching liquid crystal cell; the cell was embedded in pyramid-coupled waveguide with different alternating current (AC) and direct current (DC) voltages. The curves of the applied DC with voltage similar to that of AC shift to the left or the right. Experimental results were then compared with theoretical results derived from elastic continuum theory and multi-layer optical theory of liquid crystals. The approximate value of the flexoelectric coefficient (e1-e3) of MS-N01300-000 is 9.0 × 10-11 C/m.
Exploring Bundling Theory with Geometry
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…
Bundling Information Goods: Pricing, Profits, and Efficiency
Yannis Bakos; Erik Brynjolfsson
1999-01-01
We study the strategy of bundling a large number of information goods, such as those increasingly available on the Internet, and selling them for a fixed price. We analyze the optimal bundling strategies for a multiproduct monopolist, and we find that bundling very large numbers of unrelated information goods can be surprisingly profitable. The reason is that the law of large numbers makes it much easier to predict consumers' valuations for a bundle of goods than their valuations for the indi...
Failure properties of fiber bundle models
Pradhan, Srutarshi; Chakrabarti, Bikas K.
2003-01-01
We study the failure properties of fiber bundles when continuous rupture goes on due to the application of external load on the bundles. We take the two extreme models: equal load sharing model (democratic fiber bundles) and local load sharing model. The strength of the fibers are assumed to be distributed randomly within a finite interval. The democratic fiber bundles show a solvable phase transition at a critical stress (load per fiber). The dynamic critical behavior is obtained analyticall...
Quantum principal bundles and corresponding gauge theories
Durdevic, M
1995-01-01
A generalization of classical gauge theory is presented, in the framework of a noncommutative-geometric formalism of quantum principal bundles over smooth manifolds. Quantum counterparts of classical gauge bundles, and classical gauge transformations, are introduced and investigated. A natural differential calculus on quantum gauge bundles is constructed and analyzed. Kinematical and dynamical properties of corresponding gauge theories are discussed.
Higher order jet prolongations type gauge natural bundles over vector bundles
Directory of Open Access Journals (Sweden)
Jan Kurek
2004-05-01
Full Text Available Let $rgeq 3$ and $mgeq 2$ be natural numbers and $E$ be a vector bundle with $m$-dimensional basis. We find all gauge natural bundles ``similar" to the $r$-jet prolongation bundle $J^rE$ of $E$. We also find all gauge natural bundles ``similar" to the vector $r$-tangent bundle $(J^r_{fl}(E,R_0^*$ of $E$.
Quantum bundles and their symmetries
International Nuclear Information System (INIS)
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 the authors show how to construct EG and HG when G is U(1) or U(1) x 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. The method is illustrated with concrete examples, such as a system of charges and monopoles. The authors argue also that P is a sort of superbundle from which a large variety of bundles can be obtained by imposing suitable equivalence relations
Photonic bandgap fiber bundle spectrometer
Hang, Qu; Syed, Imran; Guo, Ning; Skorobogatiy, Maksim
2010-01-01
We experimentally demonstrate an all-fiber spectrometer consisting of a photonic bandgap fiber bundle and a black and white CCD camera. Photonic crystal fibers used in this work are the large solid core all-plastic Bragg fibers designed for operation in the visible spectral range and featuring bandgaps of 60nm - 180nm-wide. 100 Bragg fibers were chosen to have complimentary and partially overlapping bandgaps covering a 400nm-840nm spectral range. The fiber bundle used in our work is equivalent in its function to a set of 100 optical filters densely packed in the area of ~1cm2. Black and white CCD camera is then used to capture spectrally "binned" image of the incoming light at the output facet of a fiber bundle. To reconstruct the test spectrum from a single CCD image we developed an algorithm based on pseudo-inversion of the spectrometer transmission matrix. We then study resolution limit of this spectroscopic system by testing its performance using spectrally narrow test peaks (FWHM 5nm-25nm) centered at va...
Bundling and joint marketing by rival firms
Jeitschko, Thomas D.; Jung, Yeonjei; Kim, Jaesoo
2014-01-01
We study joint marketing arrangements by competing firms who engage in price discrimination between consumers who patronize only one firm (single purchasing) and those who purchase from both competitors (bundle purchasers). Two types of joint marketing are considered. Firms either commit to a component-price that applies to bundle-purchasers and then firms set stand-alone prices for single purchasers; or firms commit to a rebate off their stand alone price that will be applied to bundle-purch...
Static stress analysis of CANFLEX fuel bundles
International Nuclear Information System (INIS)
The static stress analysis of CANFLEX bundles is performed to evaluate the fuel structural integrity during the refuelling service. The structure analysis is carried out by predicting the drag force, stress and displacements of the fuel bundle. By the comparison of strength tests and analysis results, the displacement values are well agreed within 15%. The analysis shows that the CANFLEX fuel bundle keep its structural integrity. 24 figs., 6 tabs., 12 refs. (Author) .new
Damping Properties of the Hair Bundle
Baumgart, Johannes; Kozlov, Andrei S.; Risler, Thomas; Hudspeth, A. James
2015-01-01
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 b...
General frame structures on quantum principal bundles
Durdevic, M
1996-01-01
A noncommutative-geometric generalization of the classical formalism of frame bundles is developed, incorporating into the theory of quantum principal bundles the concept of the Levi-Civita connection. The construction of a natural differential calculus on quantum principal frame bundles is presented, including the construction of the associated differential calculus on the structure group. General torsion operators are defined and analyzed. Illustrative examples are presented.
Statistical Constitutive Equation of Aramid Fiber Bundles
Institute of Scientific and Technical Information of China (English)
熊杰; 顾伯洪; 王善元
2003-01-01
Tensile impact tests of aramid (Twaron) fiber bundles were carried om under high strain rates with a wide range of 0. 01/s～1000/s by using MTS and bar-bar tensile impact apparatus. Based on the statistical constitutive model of fiber bundles, statistical constitutive equations of aramid fiber bundles are derived from statistical analysis of test data at different strain rates. Comparison between the theoretical predictions and experimental data indicates statistical constitutive equations fit well with the experimental data, and statistical constitutive equations of fiber bundles at different strain rates are valid.
Parallel transport on principal bundles over stacks
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.
Hydraulic characteristics of HANARO fuel bundles
Energy Technology Data Exchange (ETDEWEB)
Cho, S.; Chung, H. J.; Chun, S. Y.; Yang, S. K.; Chung, M. K. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1997-12-31
This paper presents the hydraulic characteristics measured by using LDV (Laser Doppler Velocimetry) in subchannels of HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids, which are arranged in cylindrical configuration. The effects of the spacer grids on the turbulent flow were investigated by the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of fuel bundle and loss coefficients for the spacer grids were estimated from the measured pressure drops. Implications regarding the turbulent thermal mixing were discussed. Vibration test results measured by using laser vibrometer were presented. 9 refs., 12 figs. (Author)
Jacobi Structures on Affine Bundles
Institute of Scientific and Technical Information of China (English)
J. GRABOWSKI; D. IGLESIAS; J. C. MARRERO; E. PADR(O)N; P. URBA(N)SKI
2007-01-01
We study affine Jacobi structures (brackets) on an affine bundle π: A→M, i.e. Jacobi brackets that close on affine functions. We prove that if the rank of A is non-zero, there is a one-to- one correspondence between affine Jacobi structures on A and Lie algebroid structures on the vector bundle A+=∪p∈M Aff(Ap, R) of affine functionals. In the case rank A = 0, it is shown that there is a one-to-one correspondence between affins Jacobi structures on A and local Lie algebras on A+. Some examples and applications, also for the linear case, are discussed. For a special type of affine Jacobi structures which are canonically exhibited (strongly-affine or affine-homogeneous Jacobi structures) over a real vector space of finite dimension, we describe the leaves of its characteristic foliation as the orbits of an affine representation. These afline Jacobi structures can be viewed as an analog of the Kostant-Arnold-LiouviUe linear Poisson structure on the dual space of a real finite-dimensional Lie algebra.
Anatomic Double-bundle ACL Reconstruction
V.M. Schreiber; C.F. van Eck; F.H. Fu
2010-01-01
Rupture of the anterior cruciate ligament (ACL) is one of the most frequent forms of knee trauma. The traditional surgical treatment for ACL rupture is single-bundle reconstruction. However, during the past few years there has been a shift in interest toward double-bundle reconstruction to closely r
The Verlinde formula for Higgs bundles
Andersen, Jørgen Ellegaard; Pei, Du
2016-01-01
We propose and prove the Verlinde formula for the quantization of the Higgs bundle moduli spaces and stacks for any simple and simply-connected group. This generalizes the equivariant Verlinde formula for the case of $SU(n)$ proposed previously by the second and third author. We further establish a Verlinde formula for the quantization of parabolic Higgs bundle moduli spaces and stacks.
Principal Bundles on the Projective Line
Indian Academy of Sciences (India)
V B Mehta; S Subramanian
2002-08-01
We classify principal -bundles on the projective line over an arbitrary field of characteristic ≠ 2 or 3, where is a reductive group. If such a bundle is trivial at a -rational point, then the structure group can be reduced to a maximal torus.
Fock modules and noncommutative line bundles
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.
Damping Properties of the Hair Bundle
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.
Line bundle embeddings for heterotic theories
Energy Technology Data Exchange (ETDEWEB)
Groot Nibbelink, Stefan [Muenchen Univ. (Germany). Arnold Sommerfeld Center for Theoretical Physics; Ruehle, Fabian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2016-03-15
In heterotic string theories consistency requires the introduction of a non-trivial vector bundle. This bundle breaks the original ten-dimensional gauge groups E{sub 8} x E{sub 8} or SO(32) for the supersymmetric heterotic string theories and SO(16) x 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.
Double Fell bundles and Spectral triples
Martins, Rachel A D
2007-01-01
As a natural and canonical extension of Kumjian's Fell bundles over groupoids \\cite{fbg}, we give a definition for a double Fell bundle (a double category) over a double groupoid. We show that finite dimensional double category Fell line bundles tensored with their dual with $S^o$-reality satisfy the finite real spectral triples axioms but not necessarily orientability. This means that these product bundles with noncommutative algebras can be regarded as noncommutative compact manifolds more general than real spectral triples as they are not necessarily orientable. By construction, they unify the noncommutative geometry axioms and hence provide an algebraic enveloping structure for finite spectral triples to give the Dirac operator $D$ new algebraic and geometric structures that are otherwise missing in the transition from Fredholm operator to Dirac operator. The Dirac operator in physical applications as a result becomes less ad hoc. The new noncommutative space we present is a complex line bundle over a dou...
Line bundle embeddings for heterotic theories
Nibbelink, Stefan Groot
2016-01-01
In heterotic theories consistency requires the introduction of a non-trivial vector bundle. This bundle breaks the original ten-dimensional gauge groups E_8 x E_8 or SO(32) for the supersymmetric heterotic theories and SO(16) x 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.
On Harder–Narasimhan Reductions for Higgs Principal Bundles
Indian Academy of Sciences (India)
Arijit Dey; R Parthasarathi
2005-05-01
The existence and uniqueness of – reduction for the Higgs principal bundles over nonsingular projective variety is shown. We also extend the notion of – reduction for (, )-bundles and ramified -bundles over a smooth curve.
Scale dependence of mechanics and dynamics of active gels with increasing motor concentration
Sonn-Segev, Adar; Roichman, Yael
2016-01-01
The cytoskeleton protein actin assembles into large bundles when supporting stresses in the cell, but grows into a fine branched network to induce cell motion. Such self-organization processes are studied in artificial networks of cytoskeleton proteins with thick actin bundles and large motor protein aggregates to enable optical observation. The effect of motor aggregate size on the cytoskeleton mechanical properties is studied here in networks comprised of much smaller motor assemblies. Large motor protein clusters are known to increase the stiffness of actin based networks by introducing tension and additional cross-linking cites. We find that these effects are universal to actin gels regardless of actin bundle thickness and motor aggregate size and are relevant, therefore, to a wide range of cytoskeleton based cellular processes. In contrast, motor induced active fluctuations depend significantly on motor assembly size, featuring unique non-Gaussian statistics at high concentrations of small assemblies.
Prioritary omalous bundles on Hirzebruch surfaces
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).
Singular hermitian metrics on vector bundles
De Cataldo, M A A
1997-01-01
We introduce a notion of singular hermitian metrics (s.h.m.) for holomorphic vector bundles and define positivity in view of $L^2$-estimates. Associated with a suitably positive s.h.m. there is a (coherent) sheaf 0-th kernel of a certain $d''$-complex. We prove a vanishing theorem for the cohomology of this sheaf. All this generalizes to the case of higher rank known results of Nadel for the case of line bundles. We introduce a new semi-positivity notion, $t$-nefness, for vector bundles, establish some of its basic properties and prove that on curves it coincides with ordinary nefness. We particularize the results on s.h.m. to the case of vector bundles of the form $E=F \\otimes L$, where $F$ is a $t$-nef vector bundle and $L$ is a positive (in the sense of currents) line bundle. As applications we generalize to the higher rank case 1) Kawamata-Viehweg Vanishing Theorem, 2) the effective results concerning the global generation of jets for the adjoint to powers of ample line bundles, and 3) Matsusaka Big Theor...
Deformations of the generalised Picard bundle
International Nuclear Information System (INIS)
Let X be a nonsingular algebraic curve of genus g ≥ 3, and let Mξ denote the moduli space of stable vector bundles of rank n ≥ 2 and degree d with fixed determinant ξ over X such that n and d are coprime. We assume that if g = 3 then n ≥ 4 and if g = 4 then n ≥ 3, and suppose further that n0, d0 are integers such that n0 ≥ 1 and nd0 + n0d > nn0(2g - 2). Let E be a semistable vector bundle over X of rank n0 and degree d0. The generalised Picard bundle Wξ(E) is by definition the vector bundle over Mξ defined by the direct image pMξ *(Uξ x pX*E) where Uξ is a universal vector bundle over X x Mξ. We obtain an inversion formula allowing us to recover E from Wξ(E) and show that the space of infinitesimal deformations of Wξ(E) is isomorphic to H1(X, End(E)). This construction gives a locally complete family of vector bundles over Mξ parametrised by the moduli space M(n0,d0) of stable bundles of rank n0 and degree d0 over X. If (n0,d0) = 1 and Wξ(E) is stable for all E is an element of M(n0,d0), the construction determines an isomorphism from M(n0,d0) to a connected component M0 of a moduli space of stable sheaves over Mξ. This applies in particular when n0 = 1, in which case M0 is isomorphic to the Jacobian J of X as a polarised variety. The paper as a whole is a generalisation of results of Kempf and Mukai on Picard bundles over J, and is also related to a paper of Tyurin on the geometry of moduli of vector bundles. (author)
Geometry of quantum principal bundles, 1
Durdevic, M
1995-01-01
A theory of principal bundles possessing quantum structure groups and classical base manifolds is presented. Structural analysis of such quantum principal bundles is performed. A differential calculus is constructed, combining differential forms on the base manifold with an appropriate differential calculus on the structure quantum group. Relations between the calculus on the group and the calculus on the bundle are investigated. A concept of (pseudo)tensoriality is formulated. The formalism of connections is developed. In particular, operators of horizontal projection, covariant derivative and curvature are constructed and analyzed. Generalizations of the first structure equation and of the Bianchi identity are found. Illustrative examples are presented.
Weak equivalence classes of complex vector bundles
Hông-Vân Lê
2006-01-01
For any complex vector bundle Ek of rank k over a manifold Mm with Chern classes ci Î H2i(Mm, Z) and any non-negative integers l1, . . ., lk we show the existence of a positive number p(m, k) and the existence of a complex vector bundle Êk over Mm whose Chern classes are p(m, k) × li × ci Î H2i(Mm, Z). We also discuss a version of this statement for holomorphic vector bundles over projective algebraic manifolds.
Vector supersymmetry in the universal bundle
International Nuclear Information System (INIS)
We present a vector supersymmetry for Witten-type topological gauge theories, and examine its algebra in terms of a superconnection formalism. When covariant constraints on the supercurvature are chosen, a correspondence is established with the universal bundle construction of Atiyah and Singer. The vector supersymmetry represents a certain shift operator in the curvature of the universal bundle, and can be used to generate the hierarchy of observables in these theories. This formalism should lead to the construction of vector supergravity theories, and perhaps to the gravitational analogue of the universal bundle. (orig.)
Amber L. Jolly; Chi-Hao Luan; Brendon E. Dusel; Sara F. Dunne; Michael Winding; Vishrut J. Dixit; Chloe Robins; Jennifer L. Saluk; David J. Logan; Anne E. Carpenter; Manu Sharma; Deborah Dean; Andrew R. Cohen; Vladimir I. Gelfand
2016-01-01
Long-distance intracellular transport of organelles, mRNA, and proteins (“cargo”) occurs along the microtubule cytoskeleton by the action of kinesin and dynein motor proteins, but the vast network of factors involved in regulating intracellular cargo transport are still unknown. We capitalize on the Drosophila melanogaster S2 model cell system to monitor lysosome transport along microtubule bundles, which require enzymatically active kinesin-1 motor protein for their formation. We use an auto...
Jolly, Amber L.; Luan, Chi-Hao; Dusel, Brendon E.; Dunne, Sara Fernandez; Winding, Michael; Dixit, Vishrut J.; Robins, Chloe; Saluk, Jennifer L.; Logan, David J.; Carpenter, Anne E.; Sharma, Manu; Dean, Deborah; Cohen, Andrew R.; Gelfand, Vladimir I.
2016-01-01
Long-distance intracellular transport of organelles, mRNA, and proteins (“cargo”) occurs along the microtubule cytoskeleton by the action of kinesin and dynein motor proteins; the vast network of factors involved in regulating intracellular cargo transport are still unknown. We capitalize on the Drosophila melanogaster S2 model cell system to monitor lysosome transport along microtubule bundles, which require enzymatically active kinesin-1 motor protein for their formation. We use an automate...
Characterization of adaptation motors in saccular hair cells by fluctuation analysis.
Frank, Jonathan E.; Markin, Vladislav; Jaramillo, Fernán
2002-01-01
The mechanical sensitivity of hair cells, the sensory receptors of the vestibular and auditory systems, is maintained by adaptation, which resets the transducer to cancel the effects of static stimuli. Adaptation motors in hair cells can be experimentally activated by externally applying a transduction channel blocker to the hair bundle, causing the hair bundle to move in the negative direction. We studied the variance in the position of the hair bundle during these displacements and found th...
Institute of Scientific and Technical Information of China (English)
YU Wei-dong; YAN Hao-jing; Ron Postle; Yang Shouren
2002-01-01
Due to the effects of samples and testing conditions on fibre-bundle tensile behaviour, it is necessary to investigate the relationships between experimental factors and tensile properties for the fibre-bumdle tensile tester (TENSOR). The effects of bundle sample preparation, fibre bundle mass and fibre alignment have been tested. The experimental results indicated that (1) the low damage in combing and no free-end fibres in the cut bundle are most important for the sample preparation; (2) the reasonable bundle mass is 400- 700tex, but the tensile properties measured should bemodified with the bundle mass because a small amount of bundle mass causes the scatter results, while the larger is the bundle mass, the more difficult to comb fibres parallel and to clamp fibre evenly; and (3) the fibre irregular arrangement forms a slack bundle resulting in interaction between fibres, which will affect the reproducibility and accuracy of the tensile testing.
Liquid Flow in Shaped Fiber Bundle
Institute of Scientific and Technical Information of China (English)
ZHANG Yan; WANG Hua-ping; CHEN Yue-hua
2006-01-01
By computation and comparison of the critical spreading coefficient parameter, it was found that shaped fiber bundle is better for wetting. Liquid-air interface tension of liquid arising the shaped fiber bundle body is considered as one critical factor besides liquid viscosity, inertia force and liquid-fiber interface tension. Experimental result simulation demonstrated that the liquid-air interface tension is correlated with the geometric size of the liquid arising in body, φ0 (x) and which is affected by the cross sectional shape of fiber and the radius of single fiber. The shaped fiber bundle model is introduced to investigate liquid flow in fiber assembly. The model is generated based on a random function for stochastic forming of fibers in bundle and it is necessary to combine this fundamental model with physical explanation for investigation of liquid flow in fiber assembly.
Mobility of Taxol in Microtubule Bundles
Ross, J.
2003-06-01
Mobility of taxol inside microtubules was investigated using fluorescence recovery after photobleaching (FRAP) on flow-aligned bundles. Bundles were made of microtubules with either GMPCPP or GTP at the exchangeable site on the tubulin dimer. Recovery times were sensitive to bundle thickness and packing, indicating that taxol molecules are able to move laterally through the bundle. The density of open binding sites along a microtubule was varied by controlling the concentration of taxol in solution for GMPCPP samples. With > 63% sites occupied, recovery times were independent of taxol concentration and, therefore, inversely proportional to the microscopic dissociation rate, k_{off}. It was found that 10*k_{off} (GMPCPP) ~ k_{off} (GTP), consistent with, but not fully accounting for, the difference in equilibrium constants for taxol on GMPCPP and GTP microtubules. With taxol along the microtubule interior is hindered by rebinding events when open sites are within ~7 nm of each other.
Quantum Bundle Description of Quantum Projective Spaces
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.
A Geometric Approach to Noncommutative Principal Bundles
Wagner, Stefan
2011-01-01
From a geometrical point of view it is, so far, not sufficiently well understood what should be a "noncommutative principal bundle". Still, there is a well-developed abstract algebraic approach using the theory of Hopf algebras. An important handicap of this approach is the ignorance of topological and geometrical aspects. The aim of this thesis is to develop a geometrically oriented approach to the noncommutative geometry of principal bundles based on dynamical systems and the representation theory of the corresponding transformation group.
Parahoric bundles on a compact Riemann surface
Balaji, V
2010-01-01
Let $X$ be a compact Riemann surface of genus $g \\geq 2$. The aim of this paper is to study homomorphisms of certain discrete subgroups of $PSL(2, {\\mathbb R})$ into maximal compact subgroups of semisimple simply connected algebraic groups and relate them to torsors under a Bruhat-Tits group scheme. We also construct the moduli spaces of semistable parahoric bundles. These results generalize the theorem of Mehta and Seshadri on parabolic vector bundles.
Annular burnout data from rod bundle experiments
International Nuclear Information System (INIS)
Burnout data for annular flow in a rod bundle are presented for both transient and steady-state conditions. Tests were performed at the Oak Ridge National Laboratory in the Thermal Hydraulic Test Facility (THTF), a pressurized-water loop containing an electrically heated 64-rod bundle. The bundle configuration is typical of later generation pressurized-water reactors with 17 x 17 fuel arrays. Both axial and radial power profiles are flat. All experiments were carried out in upflow with subcooled inlet conditions, insuring accurate flow measurement. Conditions within the bundle were typical of those which could be encountered during a nuclear reactor loss-of-coolant accident. Level average fluid conditions within the test section were calculated using steady-state mass and energy conservation considerations for the steady-state tests and a transient, homogeneous, equilibrium computer code for the transient tests. Unlike tube dryout, burnout within a rod bundle does not necessarily occur at one distinct axial level. The location of individual rod dryout was determined by scanning rods axially and locating the position where rod superheat increased from approx. =0 to 30 K or greater. Thermocouple instrumentation within the bundle allows the location of dryout to be determined to within approximately +.5 cm for many of the tests
K-Theories for Certain Infinite Rank Bundles
Larrain-Hubach, Andres
2011-01-01
Several authors have recently constructed characteristic classes for classes of infinite rank vector bundles appearing in topology and physics. These include the tangent bundle to the space of maps between closed manifolds, the infinite rank bundles in the families index theorem, and bundles with pseudodifferential operators as structure group. In this paper, we construct the corresponding K-theories for these types of bundles. We develop the formalism of these theories and use their Chern ch...
Effect of left bundle branch block on TIMI frame count
Hatice Tolunay; Ahmet Kasapkara; İsa Öner Yüksel; Nurcan Başar; Ayşe Saatcı Yaşar; Mehmet Bilge
2010-01-01
Aim: Left bundle branch block is an independent risk factorfor cardiac mortality. In this study we aimed to evaluatecoronary blood flow with TIMI frame count in patients with left bundle branch block and angiographically proven normal coronary arteries.Materials and methods: We retrospectively studied 17 patients with left bundle branch block and as a control group 16 patients without left bundle branch block. All patientshad angiographically proven normal coronary arteries.Left bundle branch...
Twistor bundle theory and its application
Institute of Scientific and Technical Information of China (English)
无
2004-01-01
Over an oriented even dimensional Riemannian manifold (M2m, ds2), in terms of the Levi-Civita connection form Ω and the canonical form Θ on the bundle of positive or→ J+(M, ds2) → M. The integrability on an almost complex structure J compatible with the metric and the orientation, is shown to be equivalent to the fact that the corresponding cross section of the twistor bundle is holomorphic with respect to J and the canonical almost complex structure J1 on J+(M, ds2), by using moving frame theory. Moreover, for various metrics and a fixed orientation on M, a canonical bundle isomorphism is established. As a consequence, we generalize a celebrated theorem of LeBrun.
Tangent bundle formulation of a charged gas
Sarbach, Olivier
2013-01-01
We discuss the relativistic kinetic theory for a simple, collisionless, charged gas propagating on an arbitrary curved spacetime geometry. Our general relativistic treatment is formulated on the tangent bundle of the spacetime manifold and takes advantage of its rich geometric structure. In particular, we point out the existence of a natural metric on the tangent bundle and illustrate its role for the development of the relativistic kinetic theory. This metric, combined with the electromagnetic field of the spacetime, yields an appropriate symplectic form on the tangent bundle. The Liouville vector field arises as the Hamiltonian vector field of a natural Hamiltonian. The latter also defines natural energy surfaces, called mass shells, which turn out to be smooth Lorentzian submanifolds. A simple, collisionless, charged gas is described by a distribution function which is defined on the mass shell and satisfies the Liouville equation. Suitable fibre integrals of the distribution function define observable fie...
Porous Silicon and Denim Fiber Bundle Characterization
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.
Characteristic classes of quantum principal bundles
Durdevic, M
1995-01-01
A noncommutative-geometric generalization of classical Weil theory of characteristic classes is presented, in the conceptual framework of quantum principal bundles. A particular care is given to the case when the bundle does not admit regular connections. A cohomological description of the domain of the Weil homomorphism is given. Relations between universal characteristic classes for the regular and the general case are analyzed. In analogy with classical geometry, a natural spectral sequence is introduced and investigated. The appropriate counterpart of the Chern character is constructed, for structures admitting regular connections. Illustrative examples and constructions are presented.
Are Medicare bundles in your future?
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.
A bundle of sticks in my garden
Farran, Sue
2012-01-01
The English law of property is often described as a ‘bundle of sticks’ in which each ‘stick’ represents a particular right. Gardens challenge these rights and wreak havoc on the ‘bundle of sticks’. This paper looks at the twenty-first century manifestations of community engagement with ground and explores how ‘gardening’ is undermining concepts of ownership, possession and management of land and how the fence between what is private and what is public is being encroached and challenged by com...
Bundling in semiflexible polymers: A theoretical overview.
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
TRIGA spent fuel bundles safe storage
International Nuclear Information System (INIS)
TRIGA-SSR is a steady state research and material test reactor that has been in operation since 1980. The original TRIGA fuel was HEU (highly enriched uranium) with a U235 enrichment of 93 per cent. Almost all TRIGA HEU fuel bundles are now burned-up. Part of the spent fuel was loaded and transferred to US, in a Romania - DOE arrangement. The rest of the TRIGA fuel bundles have to be temporarily stored in the TRIGA facility. As the storage conditions had to be established with caution, neutron and thermal hydraulic evaluations of the storage conditions were required. Some criticality evaluations were made based on the SAR (Safety Analysis Report) data. Fuel constant axial temperature approximation effect is usual for criticality computations. TRIGA-SSR fuel bundle geometry and materials model for SCALE5-CSAS module allows the introduction of a fuel temperature dependency for the entire fuel active height, using different materials for each fuel bundle region. Previous RELAP5 thermal hydraulic computations for an axial and radial power distribution in the TRIGA fuel pin were done. Fuel constant temperature approximation overestimates pin factors for every core operating at high temperatures. From the thermal hydraulic point of view the worst condition of the storage grid occurs when the transfer channel is accidentally emptied of water from the pool, or the bundle is handled accidentally to remain in air. All the residual heat from the bundles has to be removed without fuel overheating and clad failure. RELAP5 computer code for residual heat removal was used in the assessment of residual heat removal. We made a couple of evaluations of TRIGA bundle clad temperatures in air cooling conditions, with different residual heat levels. The criticality computations have shown that the spent TRIGA fuel bundles storage grid is strongly sub-critical with k(eff) = 0.5951. So, there is no danger for a criticality accident for this storage grid type. The assessment is done for
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 panterior 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
Impact of bundle deformation on CHF: ASSERT-PV assessment of extended burnup Bruce B bundle G85159W
International Nuclear Information System (INIS)
This paper presents a subchannel thermalhydraulic analysis of the effect on critical heat flux (CHF) of bundle deformation such as element bow and diametral creep. The bundle geometry is based on the post-irradiation examination (PIE) data of a single bundle from the Bruce B Nuclear Generating Station, Bruce B bundle G85159W, which was irradiated for more than two years in the core during reactor commissioning. The subchannel code ASSERT-PV IST is used to assess changes in CHF and dryout power due to bundle deformation, compared to the reference, undeformed bundle. (author)
Institute of Scientific and Technical Information of China (English)
崔文静; 邢红玉; 张艳君; 叶文江; 张志东
2012-01-01
Liquid crystal cell itself may be seen as a capacitor. The effective dielectric constant of liquid crystal filled in this cell will change under an external applied voltage, which can result in the variation of the capacitance in liquid crystal cell. Based on liquid crystal elasticity theory and variational principles, the analytical expression of the capacitance in strong anchoring parallel aligned nematic liquid crystal cell is deduced theoretically. The capacitance-voltage curves of this cell are simulated numerically by using the Matlab software for different flexoelectric coefficients of liquid crystal material, from which the influence of flexoelectric effect on the capacitance of nematic liquid crystal cell is analyzed. The capacitance increases with increasing of the applied voltage whether the sum of splay and bend flexoelectric coefficient e is positive or negative and the distinct influence of flexoelectric effect appears at the lower voltage. And, the influence will vary with both the value and the sign of the flexoelectric coefficients.%液晶盒本身可以看作是一个电容器.在外加电压作用下,液晶的有效介电常数会发生变化,导致液晶盒电容的改变.基于液晶弹性理论和变分原理,理论推导平行排列向列相液晶盒电容的解析表达式,由Matlab软件数值模拟了此液晶盒的电容—电压曲线,分析了挠曲电效应对强锚泊平行排列向列相液晶盒电容的影响.无论展曲和弯曲挠曲电系数和e为正还是负,电容随电压的增大而增加,低电压条件下挠曲电效应的影响较明显.并且,挠曲电系数的大小和符号不同时,影响程度也会随之改变.
The unintended consequences of bundled payments.
Weeks, William B; Rauh, Stephen S; Wadsworth, Eric B; Weinstein, James N
2013-01-01
Consensus is building that episode-based bundled payments can produce substantial Medicare savings, and the Center for Medicare & Medicaid Innovation's Bundled Payment Initiative endorses this concept. The program generates potential cost savings by reducing the historic cost of time-defined episodes of care, provided through a discount. Although bundled payments can reduce waste primarily in the postacute care setting, concerns arise that, in an effort to maintain income levels that are necessary to cover fixed costs, providers may change their behaviors to increase the volume of episodes. Such actions would mitigate the savings that Medicare might have accrued and may perpetuate the fee-for-service payment mechanism, with episodes of care becoming the new service. Although bundled payments have some advantages over the current reimbursement system, true cost-savings to Medicare will be realized only when the federal government addresses the use issue that underlies much of the waste inherent in the system and provides ample incentives to eliminate capacity and move toward capitation.
Graph Bundling by Kernel Density Estimation
Hurter, C.; Ersoy, O.; Telea, A.
2012-01-01
We present a fast and simple method to compute bundled layouts of general graphs. For this, we first transform a given graph drawing into a density map using kernel density estimation. Next, we apply an image sharpening technique which progressively merges local height maxima by moving the convolved
Optimization of a bundle divertor for FED
International Nuclear Information System (INIS)
Optimal double-T bundle divertor configurations have been obtained for the Fusion Engineering Device (FED). On-axis ripple is minimized, while satisfying a series of engineering constraints. The ensuing non-linear optimization problem is solved via a sequence of quadratic programming subproblems, using the VMCON algorithm. The resulting divertor designs are substantially improved over previous configurations
η-Invariant and Flat Vector Bundles
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
We present an alternate definition of the mod Z component of the AtiyahPatodi-Singer η invariant associated to (not necessary unitary) fiat vector bundles, which identifies explicitly its real and imaginary parts. This is done by combining a deformation of flat connections introduced in a previous paper with the analytic continuation procedure appearing in the original article of Atiyah, Parodi and Singer.
Capacity efficiency of recovery request bundling
DEFF Research Database (Denmark)
Ruepp, Sarah Renée; Dittmann, Lars; Berger, Michael Stübert;
2010-01-01
This paper presents a comparison of recovery methods in terms of capacity efficiency. In particular, a method where recovery requests are bundled towards the destination (Shortcut Span Protection) is evaluated against traditional recovery methods. Our simulation results show that Shortcut Span...
Computations in intersection rings of flag bundles
Grayson, Daniel R; Stillman, Michael E
2012-01-01
Intersection rings of flag varieties and of isotropic flag varieties are generated by Chern classes of the tautological bundles modulo the relations coming from multiplicativity of total Chern classes. In this paper we describe the Groebner bases of the ideals of relations and give applications to computation of intersections, as implemented in Macaulay2.
Interplanetary Overlay Network Bundle Protocol Implementation
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.
Holomorphic Vector Bundle on Hopf Manifolds with Abelian Fundamental Groups
Institute of Scientific and Technical Information of China (English)
Xiang Yu ZHOU; Wei Ming LIU
2004-01-01
Let X be a Hopf manifolds with an Abelian fundamental group. E is a holomorphic vector bundle of rank r with trivial pull-back to W = Cn - {0}. We prove the existence of a non-vanishing section of L(×) E for some line bundle on X and study the vector bundles filtration structure of E. These generalize the results of D. Mall about structure theorem of such a vector bundle E.
In-pile test of Qinshan PWR fuel bundle
International Nuclear Information System (INIS)
In-pile test of Qinshan Nuclear Power Plant PWR fuel bundle has been conducted in HWRR HTHP Test loop at CIAE. The test fuel bundle was irradiated to an average burnup of 25000 Mwd/tU. The authors describe the structure of (3 x 3-2) test fuel bundle, structure of irradiation rig, fuel fabrication, irradiation conditions, power and fuel burnup. Some comments on the in-pile performance for fuel bundle, fuel rod and irradiation rig were made
Anatomic Double-Bundle Posterior Cruciate Ligament Reconstruction
Chahla, Jorge; Nitri, Marco; Civitarese, David; Dean, Chase S.; Moulton, Samuel G.; LaPrade, Robert F.
2016-01-01
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 n...
Septins promote F-actin ring formation by crosslinking actin filaments into curved bundles.
Mavrakis, Manos; Azou-Gros, Yannick; Tsai, Feng-Ching; Alvarado, José; Bertin, Aurélie; Iv, Francois; Kress, Alla; Brasselet, Sophie; Koenderink, Gijsje H; Lecuit, Thomas
2014-04-01
Animal cell cytokinesis requires a contractile ring of crosslinked actin filaments and myosin motors. How contractile rings form and are stabilized in dividing cells remains unclear. We address this problem by focusing on septins, highly conserved proteins in eukaryotes whose precise contribution to cytokinesis remains elusive. We use the cleavage of the Drosophila melanogaster embryo as a model system, where contractile actin rings drive constriction of invaginating membranes to produce an epithelium in a manner akin to cell division. In vivo functional studies show that septins are required for generating curved and tightly packed actin filament networks. In vitro reconstitution assays show that septins alone bundle actin filaments into rings, accounting for the defects in actin ring formation in septin mutants. The bundling and bending activities are conserved for human septins, and highlight unique functions of septins in the organization of contractile actomyosin rings.
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 pACL tears offers comparable clinical results to DB reconstruction in complete ACL tears. PMID:27401652
Geometry of torus bundles in integrable Hamiltonian systems
Lukina, Olga
2008-01-01
Thesis is concerned with global properties of Lagrangian bundles, i.e. symplectic n-torus bundles, as these occur in integrable Hamiltonian systems. It treats obstructions to triviality and concerns with classification of such bundles, as well as with manifestations of global invariants in real-worl
Compactifications of reductive groups as moduli stacks of bundles
DEFF Research Database (Denmark)
Martens, Johan; Thaddeus, Michael
Let G be a reductive group. We introduce the moduli problem of "bundle chains" parametrizing framed principal G-bundles on chains of lines. Any fan supported in a Weyl chamber determines a stability condition on bundle chains. Its moduli stack provides an equivariant toroidal compactification of G...
VECTOR BUNDLE, KILLING VECTOR FIELD AND PONTRYAGIN NUMBERS
Institute of Scientific and Technical Information of China (English)
周建伟
1991-01-01
Let E be a vector bundle over a compact Riemannian manifold M. We construct a natural metric on the bundle space E and discuss the relationship between the killing vector fields of E and M. Then we give a proof of the Bott-Baum-Cheeger Theorem for vector bundle E.
Stability of Picard Bundle Over Moduli Space of Stable Vector Bundles of Rank Two Over a Curve
Indian Academy of Sciences (India)
Indranil Biswas; Tomás L Gómez
2001-08-01
Answering a question of [BV] it is proved that the Picard bundle on the moduli space of stable vector bundles of rank two, on a Riemann surface of genus at least three, with fixed determinant of odd degree is stable.
Energy Technology Data Exchange (ETDEWEB)
Kaipainen, H.; Seppaenen, V.; Rinne, S.
1996-12-31
The conditions on which the bundling of the harvesting residues from spruce regeneration fellings would become profitable were studied. The calculations showed that one of the most important features was sufficient compaction of the bundle, so that the portion of the wood in the unit volume of the bundle has to be more than 40 %. The tests showed that the timber grab loader of farm tractor was insufficient for production of dense bundles. The feeding and compression device of the prototype bundler was constructed in the research and with this device the required density was obtained.The rate of compaction of the dry spruce felling residues was about 40 % and that of the fresh residues was more than 50 %. The comparison between the bundles showed that the calorific value of the fresh bundle per unit volume was nearly 30 % higher than that of the dry bundle. This means that the treatment of the bundles should be done of fresh felling residues. Drying of the bundles succeeded well, and the crushing and chipping tests showed that the processing of the bundles at the plant is possible. The treatability of the bundles was also excellent. By using the prototype, developed in the research, it was possible to produce a bundle of the fresh spruce harvesting residues, the diameter of which was about 50 cm and the length about 3 m, and the rate of compaction over 50 %. By these values the reduction target of the costs is obtainable
Multiwalled carbon nanotube reinforced biomimetic bundled gel fibres.
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
Comparison of ASSERT subchannel code with Marviken bundle data
International Nuclear Information System (INIS)
In this paper ASSERT predictions are compared with the Marviken 6-rod bundle and 36+1 rod bundle. The predictions are presented for two experiments in the 6-rod bundle and four experiments in the 36+1 rod bundle. For low inlet subcooling, the void predictions are in good agreement with the experimental data. For high inlet subcooling, however, the agreement is not as good. This is attributed to the fact that in the high inlet subcooling experiments, single phase turbulent mixing plays a more important role in determining flow conditions in the bundle
Effectiveness of Hair Bundle Motility as the Cochlear Amplifier
Sul, Bora; Iwasa, Kuni H.
2009-01-01
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 mode...
Anatomic Double-Bundle Posterior Cruciate Ligament Reconstruction.
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
Reactor application of an improved bundle divertor
International Nuclear Information System (INIS)
A Bundle Divertor was chosen as the impurity control and plasma exhaust system for the beam driven Demonstration Tokamak Hybrid Reactor - DTHR. In the context of a preconceptual design study of the reactor and associated facility a bundle divertor concept was developed and integrated into the reactor system. The overall system was found feasible and scalable for reactors with intermediate torodial field strengths on axis. The important design characteristics are: the overall average current density of the divertor coils is 0.73 kA for each tesla of toroidal field on axis; the divertor windings are made from super-conducting cables supported by steel structures and are designed to be maintainable; the particle collection assembly and auxiliary cryosorption vacuum pump are dual systems designed such that they can be reactivated alterntively to allow for continuous reactor operation; and the power requirement for energizing and operating the divertor is about 5 MW
Heterotic String Compactification and New Vector Bundles
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.
Venereau polynomials and related fiber bundles
Kaliman, Shulim; ZAIDENBERG, MIKHAIL
2003-01-01
The Venereau polynomials v-n:=y+x^n(xz+y(yu+z^2)), n>= 1, on A4 have all fibers isomorphic to the affine space A3. Moreover, for all n>= 1 the map (v-n, x) : A4 -> A2 yields a flat family of affine planes over A2. In the present note we show that over the punctured plane A2\\0, this family is a fiber bundle. This bundle is trivial if and only if v-n is a variable of the ring C[x][y,z,u] over C[x]. It is an open question whether v1 and v2 are variables of the polynomial ring C[x,y,z,u]. S. Vene...
Covariance and the hierarchy of frame bundles
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.
Rod bundle burnout data and correlation comparisons
International Nuclear Information System (INIS)
Rod bundle burnout data from 30 steady-state and 3 transient tests were obtained from experiments performed in the Thermal Hydraulic Test Facility at the Oak Ridge National Laboratory. The tests covered a parameter range relevant to intact core reactor accidents ranging from large break to small break loss-ofcoolant conditions. Instrumentation within the 64-rod test section indicated that burnout occurred over an axial range within the bundle. The distance from the point where the first dry rod was detected to the point where all rods were dry was up to 60 cm in some of the tests. The burnout data should prove useful in developing new correlations for use in reactor thermalhydraulic codes. Evaluation of several existing critical heat flux correlations using the data show that three correlations, the Barnett, Bowring, and Katto correlations, perform similarly and correlate the data better than the Biasi correlation
Deformations of Fell bundles and twisted graph algebras
Raeburn, Iain
2016-11-01
We consider Fell bundles over discrete groups, and the C*-algebra which is universal for representations of the bundle. We define deformations of Fell bundles, which are new Fell bundles with the same underlying Banach bundle but with the multiplication deformed by a two-cocycle on the group. Every graph algebra can be viewed as the C*-algebra of a Fell bundle, and there are are many cocycles of interest with which to deform them. We thus obtain many of the twisted graph algebras of Kumjian, Pask and Sims. We demonstate the utility of our approach to these twisted graph algebras by proving that the deformations associated to different cocycles can be assembled as the fibres of a C*-bundle.
Radiological evidence for the triple bundle anterior cruciate ligament.
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
Laplane, D.; Degos, J D
1983-01-01
Motor neglect is characterised by an underutilisation of one side, without defects of strength, reflexes or sensibility. Twenty cases of frontal, parietal and thalamic lesions causing motor neglect, but all without sensory neglect, are reported. It is proposed that the cerebral structures involved in motor neglect are the same as those for sensory neglect and for the preparation of movement. As in sensory neglect, the multiplicity of the structures concerned suggests that this interconnection...
Using Advanced Fuel Bundles in CANDU Reactors
International Nuclear Information System (INIS)
Improving the exit fuel burnup in CANDU reactors was a long-time challenge for both bundle designers and performance analysts. Therefore, the 43-element design together with several fuel compositions was studied, in the aim of assessing new reliable, economic and proliferation-resistant solutions. Recovered Uranium (RU) fuel is intended to be used in CANDU reactors, given the important amount of slightly enriched Uranium (~0.96% w/o U235) that might be provided by the spent LWR fuel recovery plants. Though this fuel has a far too small U235 enrichment to be used in LWR's, it can be still used to fuel CANDU reactors. Plutonium based mixtures are also considered, with both natural and depleted Uranium, either for peacefully using the military grade dispositioned Plutonium or for better using Plutonium from LWR reprocessing plants. The proposed Thorium-LEU mixtures are intended to reduce the Uranium consumption per produced MW. The positive void reactivity is a major concern of any CANDU safety assessment, therefore reducing it was also a task for the present analysis. Using the 43-element bundle with a certain amount of burnable poison (e.g. Dysprosium) dissolved in the 8 innermost elements may lead to significantly reducing the void reactivity. The expected outcomes of these design improvements are: higher exit burnup, smooth/uniform radial bundle power distribution and reduced void reactivity. Since the improved fuel bundles are intended to be loaded in existing CANDU reactors, we found interesting to estimate the local reactivity effects of a mechanical control absorber (MCA) on the surrounding fuel cells. Cell parameters and neutron flux distributions, as well as macroscopic cross-sections were estimated using the transport code DRAGON and a 172-group updated nuclear data library. (author)
Effective freeness of adjoint line bundles
Heier, Gordon
2001-01-01
In this note we establish a new Fujita-type effective bound for the base point freeness of adjoint line bundles on a compact complex projective manifold of complex dimension $n$. The bound we obtain (approximately) differs from the linear bound conjectured by Fujita only by a factor of the cube root of $n$. As an application, a new effective statement for pluricanonical embeddings is derived.
On Complex Supermanifolds with Trivial Canonical Bundle
Groeger, Josua
2016-01-01
We give an algebraic characterisation for the triviality of the canonical bundle of a complex supermanifold in terms of a certain Batalin-Vilkovisky superalgebra structure. As an application, we study the Calabi-Yau case, in which an explicit formula in terms of the Levi-Civita connection is achieved. Our methods include the use of complex integral forms and the recently developed theory of superholonomy.
Uncovering ecosystem service bundles through social preferences.
Directory of Open Access Journals (Sweden)
Berta Martín-López
Full Text Available 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.
Quantum principal bundles and their characteristic classes
Durdevic, M
1996-01-01
A brief exposition of the general theory of characteristic classes of quantum principal bundles is given. The theory of quantum characteristic classes incorporates ideas of classical Weil theory into the conceptual framework of non-commutative differential geometry. A purely cohomological interpretation of the Weil homomorphism is given, together with a standard geometrical interpretation via quantum invariant polynomials. A natural spectral sequence is described. Some quantum phenomena appearing in the formalism are discussed.
Abelian conformal field theory and determinant bundles
DEFF Research Database (Denmark)
Andersen, Jørgen Ellegaard; Ueno, K.
2007-01-01
Following [10], we study a so-called bc-ghost system of zero conformal dimension from the viewpoint of [14, 16]. We show that the ghost vacua construction results in holomorphic line bundles with connections over holomorphic families of curves. We prove that the curvature of these connections are...... nodal curves. These results are used in [4] to construct modular functors form the conformal field theories given in [14, 16] by twisting with an appropriate factional power of this Abelian theory.......Following [10], we study a so-called bc-ghost system of zero conformal dimension from the viewpoint of [14, 16]. We show that the ghost vacua construction results in holomorphic line bundles with connections over holomorphic families of curves. We prove that the curvature of these connections...... are up to a scale the same as the curvature of the connections constructed in [14, 16]. We study the sewing construction for nodal curves and its explicit relation to the constructed connections. Finally we construct preferred holomorphic sections of these line bundles and analyze their behaviour near...
Bundling harvester; Harvennuspuun automaattisen nippukorjausharvesterin kehittaeminen
Energy Technology Data Exchange (ETDEWEB)
Koponen, K. [Eko-Log Oy, Kuopio (Finland)
1997-12-01
The starting point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automating of the harvester, and automated loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilisation of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilised without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilisation of wood-energy. (orig.)
An analytical fiber bundle model for pullout mechanics of root bundles
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, 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 changing the distribution's shape increases
A Tannakian approach to dimensional reduction of principal bundles
Álvarez-Cónsul, Luis; García-Prada, Oscar
2016-01-01
Let $P$ be a parabolic subgroup of a connected simply connected complex semisimple Lie group $G$. Given a compact K\\"ahler manifold $X$, the dimensional reduction of $G$-equivariant holomorphic vector bundles over $X\\times G/P$ was carried out by the first and third authors. This raises the question of dimensional reduction of holomorphic principal bundles over $X\\times G/P$. The method used for equivariant vector bundles does not generalize to principal bundles. In this paper, we adapt to equivariant principal bundles the Tannakian approach of Nori, to describe the dimensional reduction of $G$-equivariant principal bundles over $X\\times G/P$, and to establish a Hitchin--Kobayashi type correspondence. In order to be able to apply the Tannakian theory, we need to assume that $X$ is a complex projective manifold.
Monopoles and Modifications of Bundles over Elliptic Curves
Directory of Open Access Journals (Sweden)
Andrey M. Levin
2009-06-01
Full Text Available Modifications of bundles over complex curves is an operation that allows one to construct a new bundle from a given one. Modifications can change a topological type of bundle. We describe the topological type in terms of the characteristic classes of the bundle. Being applied to the Higgs bundles modifications establish an equivalence between different classical integrable systems. Following Kapustin and Witten we define the modifications in terms of monopole solutions of the Bogomolny equation. We find the Dirac monopole solution in the case R × (elliptic curve. This solution is a three-dimensional generalization of the Kronecker series. We give two representations for this solution and derive a functional equation for it generalizing the Kronecker results. We use it to define Abelian modifications for bundles of arbitrary rank. We also describe non-Abelian modifications in terms of theta-functions with characteristic.
Amplitude death of coupled hair bundles with stochastic channel noise
Kim, Kyung-Joong
2014-01-01
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, the amplitude death phenomenon has been proposed [K.-H. Ahn, J. R. Soc. Interface, {\\bf 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 non-identical 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 inter-bundle coupling str...
Differential geometry of complex vector bundles
Kobayashi, Shoshichi
2014-01-01
Holomorphic vector bundles have become objects of interest not only to algebraic and differential geometers and complex analysts but also to low dimensional topologists and mathematical physicists working on gauge theory. This book, which grew out of the author's lectures and seminars in Berkeley and Japan, is written for researchers and graduate students in these various fields of mathematics. Originally published in 1987. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeto
Riemann Surfaces: Vector Bundles, Physics, and Dynamics
DEFF Research Database (Denmark)
Sikander, Shehryar
We construct quantum representation of a subgroup of the mapping class group of a genus two surface. Our construction relies on realizing this subgroup as the orbifold fundamental group of a Teichmueller curve, pulling back the Hitchin connection to this Tecihmueller curve, and computing...... the monodromy with respect to the pulled back connection. The formula for the representation includes a series with coefficients as iterated integrals. This series is closely related to the cyclotomic version of the Drinfel'd associator. The geodesic flow in the unit the tangent bundle of this Teichmueller...
Compression of a bundle of light rays.
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.
Tiling spaces are Cantor set fiber bundles
Sadun, Lorenzo; Williams, R F
2001-01-01
We prove that fairly general spaces of tilings of R^d are fiber bundles over the torus T^d, with totally disconnected fiber. This was conjectured (in a weaker form) in [W3], and proved in certain cases. In fact, we show that each such space is homeomorphic to the d-fold suspension of a Z^d subshift (or equivalently, a tiling space whose tiles are marked unit d-cubes). The only restrictions on our tiling spaces are that 1) the tiles are assumed to be polygons (polyhedra if d>2) that meet full-...
Higher order mechanics on graded bundles
International Nuclear Information System (INIS)
In this paper we develop a geometric approach to higher order mechanics on graded bundles in both, the Lagrangian and Hamiltonian formalism, via the recently discovered weighted algebroids. We present the corresponding Tulczyjew triple for this higher order situation and derive in this framework the phase equations from an arbitrary (also singular) Lagrangian or Hamiltonian, as well as the Euler–Lagrange equations. As important examples, we geometrically derive the classical higher order Euler–Lagrange equations and analogous reduced equations for invariant higher order Lagrangians on Lie groupoids. (paper)
The equivalence of bundling and advance sales
Alexandrov, Alexei; Bedre-Defolie, Özlem
2013-01-01
We show that a monopolist's problem of optimal advance selling strategy can be mathematically transformed into a problem of optimal bundling strategy if four conditions hold: i. consumers and the firm agree on the probability of the states occurring, ii. the firm pre-commits to the spot prices to be charged in the advance selling stage, iii. consumers are risk-neutral, and iv. consumers and the firm do not have time preferences or when they do have time preferences, they discount future at th...
2007-01-01
Mostramos la construcción de un modelo de motor homopolar, uno de los más antiguos tipos de motores eléctricos. Se caracterizan porque el campo magnético del imán mantiene siempre la misma polaridad (de ahí su nombre, del griego homos, igual), de modo que, cuando una corriente eléctrica atraviesa el campo magnético, aparece una fuerza que hace girar los elementos no fijados mecánicamente. En el sencillísimo motor homopolar colgado (Schlichting y Ucke 2004), el imán puede girar ...
Non-commutative P-1-bundles over commutative schemes
Van den Bergh, Michel
2012-01-01
In this paper we develop the theory of non-commutative P-1-bundles over commutative (smooth) schemes. Such non-commutative P-1-bundles occur in the theory of D-modules but our definition is more general. We can show that every non-commutative deformation of a Hirzebruch surface is given by a non-commutative P-1-bundle over P-1 in our sense.
Bohr--Sommerfeld Lagrangians of moduli spaces of Higgs bundles
DEFF Research Database (Denmark)
Biswas, Indranil; Gammelgaard, Niels Leth; Logares, Marina
Let $X$ be a compact connected Riemann surface of genus at least two. Let $M_H(r,d)$ 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 $M_H(r,d)$ are precisely the irreducible components of the n...... of the nilpotent cone in $M_H(r,d)$. This generalizes to Higgs $G$-bundles and also to the parabolic Higgs bundles....
International Nuclear Information System (INIS)
This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.
Annular burnout data from rod-bundle experiments
International Nuclear Information System (INIS)
Burnout data for annular flow in a rod bundle are presented for both transient and steady-state conditions. Tests were performed at the Oak Ridge National Laboratory in the Thermal Hydraulic Test Facility (THTF), a pressurized-water loop containing an electrically heated 64-rod bundle. The bundle configuration is typical of later generation pressurized-water reactors with 17 x 17 fuel arrays. Both axial and radial power profiles are flat. All experiments were carried out in upflow with subcooled inlet conditions, insuring accurate flow measurement. Conditions within the bundle were typical of those which could be encountered during a nuclear reactor loss-of-coolant accident
Robust Mapping of Incoherent Fiber-Optic Bundles
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.
Bundle formation in parallel aligned polymers with competing interactions
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).
Steady-flow characteristics of bundle fluid in drawing
Energy Technology Data Exchange (ETDEWEB)
Huh, You; Kim, Jong Seong [Kyunghee University, Suwon (Korea, Republic of)
2006-07-15
Drawing is a mechanical operation attenuating material thickness to an appropriate level for the next processing or end usage. When the input material has a form of bundle or bundles made of very thin and long shaped wires or fibers, this attenuation operation is called 'bundle drawing' or 'drafting'. Bundle drawing is being used widely in manufacturing micro sized wires or staple yarns. However, the bundle processed by this operation has more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the next successive processes. In this research a mathematical model for the dynamic behavior of the bundle fluid is to be set up on the basis of general physical laws containing physical variables, i.e. linear density and velocity as the dynamic state variables of the bundle fluid. The governing equations resulting from the modeling show that they appear in a slightly different form from what they do in a continuum fluid. Then, the governing equations system is simplified in a steady state and the bundle dynamics is simulated, showing that the shape of the velocity profiles depends on two model parameters. Experiments confirm that the model parameters are to be well adjusted to show a coincidence with the theoretical analysis. The higher the drawing ratio and drawing speed are, the more sensitive becomes the bundle flow to exogenous disturbances.
Enthalpy and void distributions in subchannels of PHWR fuel bundles
Energy Technology Data Exchange (ETDEWEB)
Park, J. W.; Choi, H.; Rhee, B. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1998-12-31
Two different types of the CANDU fuel bundles have been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void fraction distribution in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From the calculated mixture enthalpy distribution at the exit of the fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful in assessing thermal behavior of the fuel bundle that could be used in CANDU reactors. 10 refs., 4 figs., 2 tabs. (Author)
Confinement-dependent friction in peptide bundles.
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
Development boiling to sprinkled tube bundle
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.
Directory of Open Access Journals (Sweden)
Masataka Deie
2015-01-01
Full Text Available Background. Posterior cruciate ligament (PCL injuries are not rare in acute knee injuries, and several recent anatomical studies of the PCL and reconstructive surgical techniques have generated improved patient results. Now, we have evaluated PCL reconstructions performed by either the single-bundle or double-bundle technique in a patient group followed up retrospectively for more than 10 years. Methods. PCL reconstructions were conducted using the single-bundle (27 cases or double-bundle (13 cases method from 1999 to 2002. The mean age at surgery was 34 years in the single-bundle group and 32 years in the double-bundle group. The mean follow-up period was 12.5 years. Patients were evaluated by Lysholm scoring, the gravity sag view, and knee arthrometry. Results. The Lysholm score after surgery was 89.1±5.6 points for the single-bundle group and 91.9±4.5 points for the double-bundle group. There was no significant difference between the methods in the side-to-side differences by gravity sag view or knee arthrometer evaluation, although several cases in both groups showed a side-to-side difference exceeding 5 mm by the latter evaluation method. Conclusions. We found no significant difference between single- and double-bundle PCL reconstructions during more than 10 years of follow-up.
On the Classification of Complex Vector Bundles of Stable Rank
Indian Academy of Sciences (India)
Constantin Bǎnicǎ; Mihai Putinar
2006-08-01
One describes, using a detailed analysis of Atiyah–Hirzebruch spectral sequence, the tuples of cohomology classes on a compact, complex manifold, corresponding to the Chern classes of a complex vector bundle of stable rank. This classification becomes more effective on generalized flag manifolds, where the Lie algebra formalism and concrete integrability conditions describe in constructive terms the Chern classes of a vector bundle.
Lexical Bundles in L1 and L2 Academic Writing
Chen, Yu-Hua; Baker, Paul
2010-01-01
This paper adopts an automated frequency-driven approach to identify frequently-used word combinations (i.e., "lexical bundles") in academic writing. Lexical bundles retrieved from one corpus of published academic texts and two corpora of student academic writing (one L1, the other L2), were investigated both quantitatively and qualitatively.…
Presenting Lexical Bundles for Explicit Noticing with Schematic Linguistic Representation
Thomson, Haidee Elizabeth
2016-01-01
Lexical bundles are essential for fluency, but their incompleteness is a stumbling block for learners. In this study, two presentation methods to increase awareness of lexical bundles through explicit noticing are explored and compared with incidental exposure. The three conditions in this study were as follows: noticing with schematic linguistic…
Quantum principal bundles as Hopf-Galois extensions
Durdevic, M
1995-01-01
It is shown that every quantum principal bundle with a compact structure group is a Hopf-Galois extension. This property naturally extends to the level of general differential structures, so that every differential calculus over a quantum principal bundle with a compact structure group is a graded-differential variant of the Hopf-Galois extension.
Subanalytic Bundles and Tubular Neighbourhoods of Zero-Loci
Indian Academy of Sciences (India)
Vishwambhar Pati
2003-08-01
We introduce the natural and fairly general notion of a subanalytic bundle (with a finite dimensional vector space of sections) on a subanalytic subset of a real analytic manifold , and prove that when is compact, there is a Baire subset of sections in whose zero-loci in have tubular neighbourhoods, homeomorphic to the restriction of the given bundle to these zero-loci.
Skeleton-Based Edge Bundling for Graph Visualization
Ersoy, Ozan; Hurter, Christophe; Paulovich, Fernando V.; Cantareira, Gabriel; Telea, Alexandru
2011-01-01
In this paper, we present a novel approach for constructing bundled layouts of general graphs. As layout cues for bundles, we use medial axes, or skeletons, of edges which are similar in terms of position information. We combine edge clustering, distance fields, and 2D skeletonization to construct p
CANDU bundle junction. Misalignment probability and pressure-drop correlation
International Nuclear Information System (INIS)
The pressure drop over the bundle junction is an important component of the pressure drop in a CANDU (Canada Deuterium Uranium) fuel channel. This component can represent from ∼ 15% for aligned bundles to ∼ 26% for rotationally misaligned bundles, and is dependent on the degree of misalignment. The geometry of the junction increases the mixing between subchannels, and hence improves the thermal performance of the bundle immediately downstream. It is therefore important to model the junction's performance adequately. This paper summarizes a study sponsored by COG (CANDU Owners Group) and an NSERC (National Science and Engineering Research Council) Industrial Research Grant, undertaken, at CRL (Chalk River Laboratories) to identify and develop a bundle-junction model for potential implementation in the ASSERT (Advanced Solution of Subchannel Equations in Reactor Thermalhydraulics) subchannel code. The work reported in this paper consists of two components of this project: an examination of the statistics of bundle misalignment, demonstrating that there are no preferred positions for the bundles and therefore all misalignment angles are equally possible; and, an empirical model for the single-phase pressure drop across the junction as a function of the misalignment angle. The second section of this paper includes a brief literature review covering the experimental, analytical and numerical studies concerning the single-phase pressure drop across bundle junctions. 32 refs., 9 figs
On the general elephant conjecture for Mori conic bundles
Prokhorov, Yu G
1996-01-01
Let $f:X\\to S$ be an extremal contraction from a threefolds with terminal singularities onto a surface (so called Mori conic bundle). We study some particular cases of such contractions: quotients of usual conic bundles and index two contractions. Assuming Reid's general elephants conjecture we also obtain a rough classification. We present many examples.
Phase Space Reduction of Star Products on Cotangent Bundles.
N. Kowalzig; N. Neumaier; M. Pflaum
2005-01-01
In this paper we construct star products on Marsden-Weinstein reduced spaces in case both the original phase space and the reduced phase space are (symplectomorphic to) cotangent bundles. Under the assumption that the original cotangent bundle $T^*Q$ carries a symplectic structure of form $\\omega_{B
Parabolic stable Higgs bundles over complete noncompact Riemann surfaces
Institute of Scientific and Technical Information of China (English)
李嘉禹; 王友德
1999-01-01
Let M be an open Riemann surface with a finite set of punctures, a complete Poincar(?)-like metric is introduced near the punctures and the equivalence between the stability of an indecomposable parabolic Higgs bundle, and the existence of a Hermitian-Einstein metric on the bundle is established.
Moduli of Parabolic Higgs Bundles and Atiyah Algebroids
DEFF Research Database (Denmark)
Logares, Marina; Martens, Johan
2010-01-01
In this paper we study the geometry of the moduli space of (non-strongly) parabolic Higgs bundles over a Riemann surface with marked points. We show that this space possesses a Poisson structure, extending the one on the dual of an Atiyah algebroid over the moduli space of parabolic vector bundles...
Helical twist controls the thickness of F-actin bundles
Claessens, M.M.A.E.; Semmrich, C.; Ramos, L.; Bausch, A.R.
2008-01-01
In the presence of condensing agents such as nonadsorbing polymer, multivalent counter ions, and specific bundling proteins, chiral biopolymers typically form bundles with a finite thickness, rather than phase-separating into a polymer-rich phase. Although short-range repulsive interactions or geome
The behaviour of Phenix fuel pin bundle under irradiation
International Nuclear Information System (INIS)
An entire Phenix sub-assembly has been mounted and sectioned after irradiation. The examination of cross-sections revealed the effects of mechanical interaction in the bundle (ovalisations and contacts between clads). According to analysis of the sodium channels, cooling of the pin bundle remained uniform. (author)
Non-abelian higher gauge theory and categorical bundle
Viennot, David
2012-01-01
A gauge theory is associated with a principal bundle endowed with a connection permitting to define horizontal lifts of paths. The horizontal lifts of surfaces cannot be defined into a principal bundle structure. An higher gauge theory is an attempt to generalize the bundle structure in order to describe horizontal lifts of surfaces. A such attempt is particularly difficult for the non-abelian case. Some structures have been proposed to realize this goal (twisted bundle, gerbes with connection, bundle gerbe, 2-bundle). Each of them uses a category in place of the total space manifold of the usual principal bundle structure. Some of them replace also the structure group by a category (more precisely a Lie crossed module viewed as a category). But the base space remains still a simple manifold (possibly viewed as a trivial category with only identity arrows). We propose a new principal categorical bundle structure, with a Lie crossed module as structure groupoid, but with a base space belonging to a bigger clas...
Bundled slaty cleavage in laminated argillite, north-central minnesota
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.
Theories of the dorsal bundle extinction effect.
Mason, S T; Iversen, S D
1979-07-01
Selective destruction of the noradrenaline systems in the rat brain using the neurotoxin 6-hydroxydopamine has been found to cause resistance to extinction in a number of behavioural situations. Several theories concerning the behavioural mechanism altered by the lesion, and hence about the role of noradrenaline in normal brain functioning, are proposed and evaluated. Theories suggesting a role for noradrenaline in activity, perseveration, internal inhibition, frustrative non-reward, motivation, or secondary reinforcement, fail to explain all the available evidence and direct tests of each theory fails to support its predictions. A model which suggests that noreadrenaline is involved in attentional behaviour, specifically in filtering out or learning to ignore irrelevant environmental stimuli, is successful in explaining all available data and direct tests of the lesioned rats' attentional capacity serve to confirm many of the predictions of an attentional theory of the dorsal bundle extinction effect.
Bundled automobile insurance coverage and accidents.
Li, Chu-Shiu; Liu, Chwen-Chi; Peng, Sheng-Chang
2013-01-01
This paper investigates the characteristics of automobile accidents by taking into account two types of automobile insurance coverage: comprehensive vehicle physical damage insurance and voluntary third-party liability insurance. By using a unique data set in the Taiwanese automobile insurance market, we explore the bundled automobile insurance coverage and the occurrence of claims. It is shown that vehicle physical damage insurance is the major automobile coverage and affects the decision to purchase voluntary liability insurance coverage as a complement. Moreover, policyholders with high vehicle physical damage insurance coverage have a significantly higher probability of filing vehicle damage claims, and if they additionally purchase low voluntary liability insurance coverage, their accident claims probability is higher than those who purchase high voluntary liability insurance coverage. Our empirical results reveal that additional automobile insurance coverage information can capture more driver characteristics and driving behaviors to provide useful information for insurers' underwriting policies and to help analyze the occurrence of automobile accidents.
Geometries and applications of active fiber bundles
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.
Habibi, Somayeh
2011-01-01
Let $G$ be a reductive algebraic group over a perfect field $k$ and $\\mathcal{G}$ a $G$-bundle over a scheme $X/k$. The main aim of this article is to study the motive associated with $\\mathcal{G}$, inside the Veovodsky Motivic categories. We consider the case that $\\charakt k=0$ (resp. $\\charakt k\\geq 0$), the motive associated to $X$ is geometrically mixed Tate (resp. geometrically cellular) and $\\mathcal{G}$ is locally trivial for the Zariski (resp. \\'etale) topology on $X$ and show that the motive of $\\mathcal{G}$ is a geometrically mixed Tate motive. Moreover for a general $X$ we construct a filtration on the motive associated to $\\mathcal{G}$ in terms of weight polytopes. Along the way we give some applications and examples.
Extendability of parallel sections in vector bundles
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.
Bundles over Quantum RealWeighted Projective Spaces
Directory of Open Access Journals (Sweden)
Tomasz Brzeziński
2012-09-01
Full Text Available The algebraic approach to bundles in non-commutative geometry and the definition of quantum real weighted projective spaces are reviewed. Principal U(1-bundles over quantum real weighted projective spaces are constructed. As the spaces in question fall into two separate classes, the negative or odd class that generalises quantum real projective planes and the positive or even class that generalises the quantum disc, so do the constructed principal bundles. In the negative case the principal bundle is proven to be non-trivial and associated projective modules are described. In the positive case the principal bundles turn out to be trivial, and so all the associated modules are free. It is also shown that the circle (coactions on the quantum Seifert manifold that define quantum real weighted projective spaces are almost free.
Artificial ciliary bundles with nano fiber tip links
Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael
2015-01-01
Mechanosensory ciliary bundles in fishes are the inspiration for carefully engineered artificial flow sensors. We report the development of a new class of ultrasensitive MEMS flow sensors that mimic the intricate morphology of the ciliary bundles, including the stereocilia, tip links, and the cupula, and thereby achieve threshold detection limits that match the biological example. An artificial ciliary bundle is achieved by fabricating closely-spaced arrays of polymer micro-pillars with gradiating heights. Tip links that form the fundamental sensing elements are realized through electrospinning aligned PVDF piezoelectric nano-fibers that link the distal tips of the polymer cilia. An optimized synthesis of hyaluronic acid-methacrylic anhydride hydrogel that results in properties close to the biological cupula, together with drop-casting method are used to form the artificial cupula that encapsulates the ciliary bundle. In testing, fluid drag force causes the ciliary bundle to slide, stretching the flexible nan...
Superconductivity in an Inhomogeneous Bundle of Metallic and Semiconducting Nanotubes
Directory of Open Access Journals (Sweden)
Ilya Grigorenko
2013-01-01
Full Text Available Using Bogoliubov-de Gennes formalism for inhomogeneous systems, we have studied superconducting properties of a bundle of packed carbon nanotubes, making a triangular lattice in the bundle's transverse cross-section. The bundle consists of a mixture of metallic and doped semiconducting nanotubes, which have different critical transition temperatures. We investigate how a spatially averaged superconducting order parameter and the critical transition temperature depend on the fraction of the doped semiconducting carbon nanotubes in the bundle. Our simulations suggest that the superconductivity in the bundle will be suppressed when the fraction of the doped semiconducting carbon nanotubes will be less than 0.5, which is the percolation threshold for a two-dimensional triangular lattice.
HORIZONTAL LAPLACE OPERATOR IN REAL FINSLER VECTOR BUNDLES
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
A vector bundle F over the tangent bundle TM of a manifold M is said to be a Finsler vector bundle if it is isomorphic to the pull-back π*E of a vector bundle E over M([1]). In this article the authors study the h-Laplace operator in Finsler vector bundles.An h-Laplace operator is defined, first for functions and then for horizontal Finsler forms on E. Using the h-Laplace operator, the authors define the h-harmonic function and h-harmonic horizontal Finsler vector fields, and furthermore prove some integral formulas for the h-Laplace operator, horizontal Finsler vector fields, and scalar fields on E.
Development of nuclear fuel. Development of CANDU advanced fuel bundle
International Nuclear Information System (INIS)
In order to develop CANDU advanced fuel, the agreement of the joint research between KAERI and AECL was made on February 19, 1991. AECL conceptual design of CANFLEX bundle for Bruce reactors was analyzed and then the reference design and design drawing of the advanced fuel bundle with natural uranium fuel for CANDU-6 reactor were completed. The CANFLEX fuel cladding was preliminarily investigated. The fabricability of the advanced fuel bundle was investigated. The design and purchase of the machinery tools for the bundle fabrication for hydraulic scoping tests were performed. As a result of CANFLEX tube examination, the tubes were found to be meet the criteria proposed in the technical specification. The dummy bundles for hydraulic scoping tests have been fabricated by using the process and tools, where the process parameters and tools have been newly established. (Author)
Introduction to the theory of fiber bundles and connections I
International Nuclear Information System (INIS)
In lectures 1 and 2 we discuss basic concepts of topology and differential geometry: definition of a topological space and of Hausdorff, compact, connected and paracompact spaces; topological groups and actions of groups on spaces; differentiable manifolds, tangent vectors and 1 forms; partitions of unity and Lie groups. In lecture 3 we present the concept of a fiber bundle and discuss vector bundles and principal bundles. The concept of a connection on a smooth vector bundle is defined in lecture 4, together with the associated concepts of curvature and parallel transport; as an illustration we present the Levi-Civita connection on a Riemannian manifold. Finally, in lecture 5 we define connections on principal bundles and present examples with the Lie groups U(1) and SU(2). For reasons of space the present article only includes lectures 1, 2 and 3. Lectures 4 and 5 will be published in a forthcoming paper. (Author)
Voltage- and calcium-dependent motility of saccular hair bundles
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.
The 2-Hilbert Space of a Prequantum Bundle Gerbe
Bunk, Severin; Szabo, Richard J
2016-01-01
We construct a prequantum 2-Hilbert space for any line bundle gerbe whose Dixmier-Douady class is torsion. Analogously to usual prequantisation, this 2-Hilbert space has the category of sections of the line bundle gerbe as its underlying 2-vector space. These sections are obtained as certain morphism categories in Waldorf's version of the 2-category of line bundle gerbes. We show that these morphism categories carry a monoidal structure under which they are semisimple and abelian. We introduce a dual functor on the sections, which yields a closed structure on the morphisms between bundle gerbes and turns the category of sections into a 2-Hilbert space. We discuss how these 2-Hilbert spaces fit various expectations from higher prequantisation. We then extend the transgression functor to the full 2-category of bundle gerbes and demonstrate its compatibility with the additional structures introduced. We discuss various aspects of Kostant-Souriau prequantisation in this setting, including its dimensional reductio...
Fiber bundle model under fluid pressure
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.
Fiber bundle model under fluid pressure.
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
Birefringence of single and bundled microtubules.
Oldenbourg, R; Salmon, E D; Tran, P T
1998-01-01
We have measured the birefringence of microtubules (MTs) and of MT-based macromolecular assemblies in vitro and in living cells by using the new Pol-Scope. A single microtubule in aqueous suspension and imaged with a numerical aperture of 1.4 had a peak retardance of 0.07 nm. The peak retardance of a small bundle increased linearly with the number of MTs in the bundle. Axonemes (prepared from sea urchin sperm) had a peak retardance 20 times higher than that of single MTs, in accordance with the nine doublets and two singlets arrangement of parallel MTs in the axoneme. Measured filament retardance decreased when the filament was defocused or the numerical aperture of the imaging system was decreased. However, the retardance "area," which we defined as the image retardance integrated along a line perpendicular to the filament axis, proved to be independent of focus and of numerical aperture. These results are in good agreement with a theory that we developed for measuring retardances with imaging optics. Our theoretical concept is based on Wiener's theory of mixed dielectrics, which is well established for nonimaging applications. We extend its use to imaging systems by considering the coherence region defined by the optical set-up. Light scattered from within that region interferes coherently in the image point. The presence of a filament in the coherence region leads to a polarization dependent scattering cross section and to a finite retardance measured in the image point. Similar to resolution measurements, the linear dimension of the coherence region for retardance measurements is on the order lambda/(2 NA), where lambda is the wavelength of light and NA is the numerical aperture of the illumination and imaging lenses. PMID:9449366
Effect of Reynolds number and bundle geometry on the turbulent flow in tight lattice bundle
International Nuclear Information System (INIS)
The flow structure in tight lattice is still of great interest to nuclear industry. The accurate prediction of flow parameter in subchannels of tight lattice is likable. Unsteady Reynolds Averaged Navier Stokes (URANS) is a promising approach to achieve this goal. The implementation of URANS (Unsteady Reynolds Averaged Navier Stokes) approach will be validated by comparing computational results with the experimental data of Krauss (1998). In this paper, the turbulent flow with different Reynolds number (5000~215000) and different P/D(1.005~1.2) are simulated with CFD code CFX12.The effects of the Reynolds number and the bundle geometry(P/D) on wall shear stress, turbulent kinetic energy, turbulent mixing and large scale coherent structure in tight lattice are analyzed in details. It is hoped that the present work will contribute to the understanding of these important flow phenomena and facilitate the prediction and design of rod bundles. (author)
Delisle, Dennis R
2013-01-01
With passage of the Affordable Care Act, the ever-evolving landscape of health care braces for another shift in the reimbursement paradigm. As health care costs continue to rise, providers are pressed to deliver efficient, high-quality care at flat to minimally increasing rates. Inherent systemwide inefficiencies between payers and providers at various clinical settings pose a daunting task for enhancing collaboration and care coordination. A change from Medicare's fee-for-service reimbursement model to bundled payments offers one avenue for resolution. Pilots using such payment models have realized varying degrees of success, leading to the development and upcoming implementation of a bundled payment initiative led by the Center for Medicare and Medicaid Innovation. Delivery integration is critical to ensure high-quality care at affordable costs across the system. Providers and payers able to adapt to the newly proposed models of payment will benefit from achieving cost reductions and improved patient outcomes and realize a competitive advantage.
Thermal Characteristics of Tube Bundles in Ultra-Supercritical Boilers
Directory of Open Access Journals (Sweden)
Seok Min Choi
2016-09-01
Full Text Available In this study, flow and thermal characteristics of tube bundles in ultra-supercritical boilers were analyzed. The local heat transfer around the tube bundles was measured to predict the local temperature distribution and vulnerable positions of the superheated tube bundles. The maximally superheated tube bundles were simulated in the laboratory and local heat transfer was measured by using the naphthalene sublimation method. The experiment was conducted on three lines of tube bundles, all with in-line arrangements. Each line consist of six tubes. The distance in the streamwise direction (Sx/∅ was 1.99 and that in the spanwise direction (Sz/∅ was 5.45. The Reynolds number varied from 5000 to 30,000, which covers a range of different operating conditions. Thermal and stress analyses were conducted numerically, based on the experimental data. The results showed that the flow characteristic changes the local heat transfer of the tube bundles. The flow impinged on the stagnation point of Tube 1 and reattached at 60° of Tube 2. The high heat transfer occurred at those positions of the tube bundles. The temperature and stress distributions on the surface of each tube bundle also varied. The reattachment point on Tube 2 had the highest heat transfer and temperature distribution. That position on Tube 2 was subjected to the highest stress due to the large temperature gradient. This result indicates that Tube 2 of the ultra-supercritical (USC boiler is the weakest of the tube bundles, changing the pitch of the streamwise direction of Tube 2 is one method to reduce the highest stress in superheater tube bundles in the USC boiler.
CHF Enhancement of Advanced 37-Element Fuel Bundles
Directory of Open Access Journals (Sweden)
Joo Hwan Park
2015-01-01
Full Text Available A standard 37-element fuel bundle (37S fuel bundle has been used in commercial CANDU reactors for over 40 years as a reference fuel bundle. Most CHF of a 37S fuel bundle have occurred at the elements arranged in the inner pitch circle for high flows and at the elements arranged in the outer pitch circle for low flows. It should be noted that a 37S fuel bundle has a relatively small flow area and high flow resistance at the peripheral subchannels of its center element compared to the other subchannels. The configuration of a fuel bundle is one of the important factors affecting the local CHF occurrence. Considering the CHF characteristics of a 37S fuel bundle in terms of CHF enhancement, there can be two approaches to enlarge the flow areas of the peripheral subchannels of a center element in order to enhance CHF of a 37S fuel bundle. To increase the center subchannel areas, one approach is the reduction of the diameter of a center element, and the other is an increase of the inner pitch circle. The former can increase the total flow area of a fuel bundle and redistributes the power density of all fuel elements as well as the CHF. On the other hand, the latter can reduce the gap between the elements located in the middle and inner pitch circles owing to the increasing inner pitch circle. This can also affect the enthalpy redistribution of the fuel bundle and finally enhance CHF or dry-out power. In this study, the above two approaches, which are proposed to enlarge the flow areas of the center subchannels, were considered to investigate the impact of the flow area changes of the center subchannels on the CHF enhancement as well as the thermal characteristics by applying a subchannel analysis method.
DEFF Research Database (Denmark)
Gammelgaard Nielsen, Anders
2011-01-01
MOTOR is the first assignment that students at Unit 1a of the School of Architecture are introduced to. The purpose of the assignment is to shake up the students and their preconceptions of what architec- ture is. This is done by introducing them to a working method that al- lows them to develop...
Institute of Scientific and Technical Information of China (English)
ISABEL DING
2008-01-01
@@ The automotive industry is often seen as a man's world. Wang Fengying (王风英) begs to differ. The 38-year-old has presided over Great Wall Motors (长城汽车), the leading pick-up truck and Sport Utility Vehicle(SUV) manufacturer in China for the past five years.
Khan, Afsha; Camilleri, Jeremy
2012-01-01
A 48-year-old immunosuppressed woman presented to a rheumatology follow-up clinic after suffering from herpes zoster infection. She had manifestations of foot drop 3 months after the initial infection. She was diagnosed with motor radiculopathy following herpes zoster infection that was effectively managed by physiotherapy and amitriptyline.
Two-categorical bundles and their classifying spaces
DEFF Research Database (Denmark)
Baas, Nils A.; Bökstedt, M.; Kro, T.A.
2012-01-01
For a 2-category 2C we associate a notion of a principal 2C-bundle. In case of the 2-category of 2-vector spaces in the sense of M.M. Kapranov and V.A. Voevodsky this gives the the 2-vector bundles of N.A. Baas, B.I. Dundas and J. Rognes. Our main result says that the geometric nerve of a good 2......-category is a classifying space for the associated principal 2-bundles. In the process of proving this we develop a lot of powerful machinery which may be useful in further studies of 2-categorical topology. As a corollary we get a new proof of the classification of principal bundles. A calculation based...... on the main theorem shows that the principal 2-bundles associated to the 2-category of 2-vector spaces in the sense of J.C. Baez and A.S. Crans split, up to concordance, as two copies of ordinary vector bundles. When 2C is a cobordism type 2-category we get a new notion of cobordism-bundles which turns out...
Energy Technology Data Exchange (ETDEWEB)
Knoth, Edward A.; Chelluri, Bhanumathi; Schumaker, Edward J.
2012-12-14
Project Summary Transportation energy usage is predicted to increase substantially by 2020. Hybrid vehicles and fuel cell powered vehicles are destined to become more prominent as fuel prices rise with the demand. Hybrid and fuel cell vehicle platforms are both dependent on high performance electric motors. Electric motors for transportation duty will require sizeable low-speed torque to accelerate the vehicle. As motor speed increases, the torque requirement decreases which results in a nearly constant power motor output. Interior permanent magnet synchronous motors (IPMSM) are well suited for this duty. , , These rotor geometries are configured in straight lines and semi circular arc shapes. These designs are of limited configurations because of the lack of availability of permanent magnets of any other shapes at present. We propose to fabricate rotors via a novel processing approach where we start with magnet powders and compact them into a net shape rotor in a single step. Using this approach, widely different rotor designs can be implemented for efficiency. The current limitation on magnet shape and thickness will be eliminated. This is accomplished by co-filling magnet and soft iron powders at specified locations in intricate shapes using specially designed dies and automatic powder filling station. The process fundamentals for accomplishing occurred under a previous Applied Technology Program titled, ÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂ¢ÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂMotors and Generators for the 21st CenturyÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂ¢ÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂ. New efficient motor designs that are not currently possible (or cost prohibitive) can be accomplished by this approach. Such an approach to
The Geometry of Tangent Bundles: Canonical Vector Fields
Directory of Open Access Journals (Sweden)
Tongzhu Li
2013-01-01
Full Text Available A canonical vector field on the tangent bundle is a vector field defined by an invariant coordinate construction. In this paper, a complete classification of canonical vector fields on tangent bundles, depending on vector fields defined on their bases, is obtained. It is shown that every canonical vector field is a linear combination with constant coefficients of three vector fields: the variational vector field (canonical lift, the Liouville vector field, and the vertical lift of a vector field on the base of the tangent bundle.
Systematic evaluation of bundled SPC water for biomolecular simulations.
Gopal, Srinivasa M; Kuhn, Alexander B; Schäfer, Lars V
2015-04-01
In bundled SPC water models, the relative motion of groups of four water molecules is restrained by distance-dependent potentials. Bundled SPC models have been used in hybrid all-atom/coarse-grained (AA/CG) multiscale simulations, since they enable to couple atomistic SPC water with supra-molecular CG water models that effectively represent more than a single water molecule. In the present work, we systematically validated and critically tested bundled SPC water models as solvent for biomolecular simulations. To that aim, we investigated both thermodynamic and structural properties of various biomolecular systems through molecular dynamics (MD) simulations. Potentials of mean force of dimerization of pairs of amino acid side chains as well as hydration free energies of single side chains obtained with bundled SPC and standard (unrestrained) SPC water agree closely with each other and with experimental data. Decomposition of the hydration free energies into enthalpic and entropic contributions reveals that in bundled SPC, this favorable agreement of the free energies is due to a larger degree of error compensation between hydration enthalpy and entropy. The Ramachandran maps of Ala3, Ala5, and Ala7 peptides are similar in bundled and unrestrained SPC, whereas for the (GS)2 peptide, bundled water leads to a slight overpopulation of extended conformations. Analysis of the end-to-end distance autocorrelation times of the Ala5 and (GS)2 peptides shows that sampling in more viscous bundled SPC water is about two times slower. Pronounced differences between the water models were found for the structure of a coiled-coil dimer, which is instable in bundled SPC but not in standard SPC. In addition, the hydration of the active site of the serine protease α-chymotrypsin depends on the water model. Bundled SPC leads to an increased hydration of the active site region, more hydrogen bonds between water and catalytic triad residues, and a significantly slower exchange of water
Bondage Numbers of C4 Bundles over a Cycle Cn
Directory of Open Access Journals (Sweden)
Moo Young Sohn
2013-01-01
Full Text Available Graph bundles generalize the notion of covering graphs and graph products. Graph bundles have been applied in computer architecture and communication networks. The bondage number is an important parameter for measuring the vulnerability and stability of the network domination under link failure. The bondage number b(G of a graph G is the minimum number of edges whose removal enlarges the domination number. In this paper, we show that the bondage number of every C4 bundles over a cycle Cn (n≥4 is equal to 4.
Thermomagnetic Siphoning on a Bundle of Current-Carrying Wires
Boulware, Jeffrey C.; Jensen, Scott
2010-01-01
Using COMSOL Multiphysics 3.5a, thermomagnetic siphoning (TMS) was shown to be a sufficient manner of regulating the temperature of a bundle of current-carrying wires wrapped with a magnetorheological fluid (MRF) jacket. As the bundle heated up, cooler MRF on the outside of the jacket was drawn towards the center due to Curie’s Law and the induced magnetic field. The process convected heat from the bundle as the MRF warmed up and was pushed out towards an isothermal jacket wall. Assuming an o...
Shatz, L F
2000-03-01
The relationship between size and shape of the hair bundle of a hair cell in the inner ear and its sensitivity at asymptotically high and low frequencies was determined, thereby extending the results of an analysis of hair bundle hydrodynamics in two dimensions (Freeman and Weiss, 1990. Hydrodynamic analysis of a two-dimensional model for micromechanical resonance of free-standing hair bundles. Hear. Res. 48, 37-68) to three dimensions. A hemispheroid was used to represent the hair bundle. The hemispheroid had a number of advantages: it could represent shapes that range from thin, pencil-like shapes, to wide, flat, disk-like shapes. Also analytic methods could be used in the high frequency range to obtain an exact solution to the equations of motion. In the low frequency range, where an approximate solution was found using boundary element methods, the sensitivity of the responses of hair cells was mainly proportional to the cube of the heights of their hair bundles, and at high frequencies, the sensitivity of the hair cells was mainly proportional to the inverse of their heights. An excellent match was obtained between measurements of sensitivity curves in the basillar papilla of the alligator and bobtail lizards and the model's predictions. These results also suggest why hair bundles of hair cells in vestibular organs which are sensitive to low frequencies have ranges of heights that are an order of magnitude larger than the range of heights of hair bundles of hair cells found in auditory organs.
LVRF fuel bundle manufacture for Bruce
Energy Technology Data Exchange (ETDEWEB)
Pant, A. [Zircatec Precision Industries, Port Hope, Ontario (Canada)
2005-12-15
In response to the Power Uprate program at Bruce Power, Zircatec has committed to introduce, by Spring 2006 a new manufacturing line for the production of 43 element Bruce LVRF bundles containing Slightly Enriched Uranium (SEU) with a centre pin of blended dysprosia/urania (BDU). This is a new fuel design and is the first change in fuel design since the introduction of the current 37-element fuel over 20 years ago. Introduction of this new line has involved the introduction of significant changes to an environment that is not used to rapid changes with significant impact. At ZPI we have been able to build on our innovative capabilities in new fuel manufacturing, the strength and experience of our core team, and on our prevailing management philosophy of 'support the doer'. The presentation will discuss some of the novel aspects of this fuel introduction and the mix of innovative and classical project management methods that are being used to ensure that project deliveries are being met. Supporting presentations will highlight some of the issues in more detail. (author)
Bundles of Norms About Teen Sex and Pregnancy.
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
Zeta Functions for Elliptic Curves I. Counting Bundles
Weng, Lin
2012-01-01
To count bundles on curves, we study zetas of elliptic curves and their zeros. There are two types, i.e., the pure non-abelian zetas defined using moduli spaces of semi-stable bundles, and the group zetas defined for special linear groups. In lower ranks, we show that these two types of zetas coincide and satisfy the Riemann Hypothesis. For general cases, exposed is an intrinsic relation on automorphism groups of semi-stable bundles over elliptic curves, the so-called counting miracle. All this, together with Harder-Narasimhan, Desale-Ramanan and Zagier's result, gives an effective way to count semi-stable bundles on elliptic curves not only in terms of automorphism groups but more essentially in terms of their $h^0$'s. Distributions of zeros of high rank zetas are also discussed.
On exact triangles consisting of stable vector bundles on tori
Kobayashi, Kazushi
2016-01-01
In this paper, we consider the exact triangles consisting of stable holomorphic vector bundles on one-dimensional complex tori, and discuss their relations with the corresponding Fukaya category via the homological mirror symmetry.
Topological T-duality for torus bundles with monodromy
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.
Mechanical Models of Microtubule Bundle Collapse in Alzheimer's Disease
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
Infinitely stably extendable vector bundles on projective spaces
Coanda, Iustin
2009-01-01
According to Horrocks (1966), a vector bundle E on the projective n-space extends stably to the projective N-space, N>n, if there exists a vector bundle on the larger space whose restriction to the smaller one is isomorphic to E plus a direct sum of line bundles. We show that E extends stably to the projective N-space for every N>n if and only if E is the cohomology of a free monad (with three terms). The proof uses the method of Coanda and Trautmann (2006). Combining this result with a theorem of Mohan Kumar, Peterson and Rao (2003), we get a new effective version of the Babylonian tower theorem for vector bundles on projective spaces.
The canonical Cartan bundle and connection in CR geometry
Herzlich, Marc
2009-01-01
minor changes ; wrong author in reference [7] corrected; International audience; We give a differential geometric description of the Cartan (or tractor) bundle and its canonical connection in CR geometry, thus offering a direct, alternative, definition to the usual abstract approach.
Deformation Quantization of Principal Fibre Bundles and Classical Gauge Theories
Wei\\ss, Stefan
2010-01-01
In this dissertation the notion of deformation quantization of principal fibre bundles is established and investigated in order to find a geometric formulation of classical gauge theories on noncommutative space-times. As a generalization, the notion of deformation quantization of surjective submersions is also discussed. It is shown that deformation quantizations of surjective submersions and principal fibre bundles always exist and are unique up to equivalence. These statements concerning complex-valued functions are moreover formulated and proved for sections of arbitrary vector bundles over the total space, in particular equivariant vector bundles. The commutants of the deformed right module structures within the differential operators, playing an inportant role with regard to the infinitesimal gauge transformations, are computed explicitly in each case. Depending on the choice of specific covariant derivatives and connections the commutants are isomorphic to the formal power series of the respective vert...
National Partnership for Maternal Safety: Consensus Bundle on Venous Thromboembolism.
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
2016-10-01
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:27636577
Bundles of Norms About Teen Sex and Pregnancy.
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.
Interactive hypermedia training manual for spent-fuel bundle counters
International Nuclear Information System (INIS)
Spent-fuel bundle counters, developed by the Canadian Safeguards Support Program for the International Atomic Energy Agency, provide a secure and independent means of counting the number of irradiated fuel bundles discharged into the fuel storage bays at CANDU nuclear power stations. Paper manuals have been traditionally used to familiarize IAEA inspectors with the operation, maintenance and extensive reporting capabilities of the bundle counters. To further assist inspectors, an interactive training manual has been developed on an Apple Macintosh computer using hypermedia software. The manual uses interactive animation and sound, in conjunction with the traditional text and graphics, to simulate the underlying operation and logic of the bundle counters. This paper presents the key features of the interactive manual and highlights the advantages of this new technology for training
Steric effects induce geometric remodeling of actin bundles in filopodia
Dobramysl, Ulrich; Erban, Radek
2016-01-01
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 the...
Quantum principal bundles and Tannaka-Krein duality theory
Durdevic, M
1995-01-01
The structure of quantum principal bundles is studied, from the viewpoint of Tannaka-Krein duality theory. It is shown that if the structure quantum group is compact, principal G-bundles over a quantum space M are in a natural correspondence with certain contravariant functors defined on the category of finite-dimensional unitary representations of G, with the values in the category of finite projective bimodules over a *-algebra representing the base space.
Quantized gauge-affine gravity in the superfiber bundle approach
Meziane, A.; Tahiri, M
2004-01-01
The quantization of gauge-affine gravity within the superfiber bundle formalism is proposed. By introducing an even pseudotensorial 1-superform over a principal superfibre bundle with superconnection, we obtain the geometrical Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST transformations of the fields occurring in such a theory. Reducing the four-dimensional general affine group double-covering to the Poincare group double-covering we also find the BRST and anti-BRST transformations of the f...
Bondage Numbers of C4 Bundles over a Cycle Cn
Moo Young Sohn; Fu-Tao Hu; Jaeun Lee
2013-01-01
Graph bundles generalize the notion of covering graphs and graph products. Graph bundles have been applied in computer architecture and communication networks. The bondage number is an important parameter for measuring the vulnerability and stability of the network domination under link failure. The bondage number $b\\left(G\\right)$ of a graph $G$ is the minimum number of edges whose removal enlarges the domination number. In this paper, we show that the bondage number of every ${C}_{4}$ bu...
Simplified modeling of EM field coupling to complex cable bundles
Schetelig, B.; J. Keghie; Kanyou Nana, R.; Fichte, L.-O.; S. Potthast; Dickmann, S.
2010-01-01
In this contribution, the procedure "Equivalent Cable Bundle Method" is used for the simplification of large cable bundles, and it is extended to the application on differential signal lines. The main focus is on the reduction of twisted-pair cables. Furthermore, the process presented here allows to take into account cables with wires that are situated quite close to each other. The procedure is based on a new approach to calculate the geometry of the simplified cable and us...
Filler metals for containers holding irradiated fuel bundles
International Nuclear Information System (INIS)
One of the procedures being considered for the disposal of Canadian deuterium uranium (CANDU) irradiated fuel bundles is to place the bundles in containers, fill the containers with metal, and place them underground. This investigation deals with the selection of the filler metal with particular reference to the reaction rate with, and bonding of the filler metal to, the fuel sheathing (Zircaloy 4) and potential container materials. Lead, zinc, and aluminium alloys were examined as potential filler metals. (U.K.)
Intra-His bundle block: clinical, electrocardiographic, and electrophysiologic characteristics
Andréa Eduardo M.; Atié Jacob; Maciel Washington A.; Oliveira Jr Nilson A. de; Camanho Luiz Eduardo; Belo Luís Gustavo; Carvalho Hecio Affonso de; Siqueira Leonardo; Saad Eduardo; Venancio Ana Claudia
2002-01-01
OBJECTIVE: To assess the clinical, electrocardiographic, and electrophysiologic characteristics of patients (pt) with intra-His bundle block undergoing an electrophysiologic study (EPS). METHODS: We analyzed the characteristics of 16 pt with second-degree atrioventricular block and symptoms of syncope or dyspnea, or both, undergoing conventional EPS. RESULTS: Intra-His bundle block was documented in 16 pt during an EPS. In 15 (94%) pt, the atrioventricular block was recorded in sinus rhythm; ...
Principal 2-bundles and their gauge 2-groups
Wockel, Christoph
2008-01-01
In this paper we introduce principal 2-bundles and show how they are classified by non-abelian Cech cohomology. Moreover, we show that their gauge 2-groups can be described by 2-group-valued functors, much like in classical bundle theory. Using this, we show that, under some mild requirements, these gauge 2-groups possess a natural smooth structure. In the last section we provide some explicit examples.
BiSet: Semantic Edge Bundling with Biclusters for Sensemaking.
Sun, Maoyuan; Mi, Peng; North, Chris; Ramakrishnan, Naren
2016-01-01
Identifying coordinated relationships is an important task in data analytics. For example, an intelligence analyst might want to discover three suspicious people who all visited the same four cities. Existing techniques that display individual relationships, such as between lists of entities, require repetitious manual selection and significant mental aggregation in cluttered visualizations to find coordinated relationships. In this paper, we present BiSet, a visual analytics technique to support interactive exploration of coordinated relationships. In BiSet, we model coordinated relationships as biclusters and algorithmically mine them from a dataset. Then, we visualize the biclusters in context as bundled edges between sets of related entities. Thus, bundles enable analysts to infer task-oriented semantic insights about potentially coordinated activities. We make bundles as first class objects and add a new layer, "in-between", to contain these bundle objects. Based on this, bundles serve to organize entities represented in lists and visually reveal their membership. Users can interact with edge bundles to organize related entities, and vice versa, for sensemaking purposes. With a usage scenario, we demonstrate how BiSet supports the exploration of coordinated relationships in text analytics.
A Radiologist's Primer on Bundles and Care Episodes.
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
Combustor having mixing tube bundle with baffle arrangement for directing fuel
Energy Technology Data Exchange (ETDEWEB)
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.
How Buyers Evaluate Product Bundles: A Model of Anchoring and Adjustment.
Yadav, Manjit S
1994-01-01
Bundling, the joint offering of two or more items, is a common selling strategy, yet little research has been conducted on buyers' evaluation of bundle offers. We developed and tested a model of bundle evaluation in which the buyers anchored their evaluation on the item perceived as most important and then made adjustments on the basis of their evaluations of the remaining bundle items. The results of two computerized laboratory experiments suggested that people tend to examine bundle items i...
Hagg, Heather (Woodward); El-Harit, Jamie; Vanni, Chris; Scott, Penny
2007-01-01
Within healthcare, clinical practice bundles have been used to implement standardized, nursing driven protocols resulting in standardized patient care and improved patient outcomes. Examples of these types of bundles include clinical practices shown through evidence based medicine to reduce occurrences of Ventilator Associated Pneumonia – VAP bundle; those shown to reduce the occurrences of central line infections – CL bundle; and those shown to significantly improve the outcomes of patients...
Damage to the medial motor system in stroke patients with motor neglect
Directory of Open Access Journals (Sweden)
Raffaella eMigliaccio
2014-06-01
Full Text Available Background and objectives. Motor neglect (MN is a clinically important condition whereby patients with unilateral brain lesions fail to move their contralateral limbs, despite normal muscle strength, reflexes, and sensation. MN has been associated with various lesion sites, including the parietal and frontal cortex, the internal capsule, the lenticulostriate nuclei, and the thalamus. In the present study, we explored the hypothesis that MN depends on a dysfunction of the medial motor system by performing a detailed anatomical analysis in four patients with MN.Methods. Ten patients participated in the study: four with MN, four with left visual neglect but without MN, and three patients with left hemiplegia without MN. We used specific scales for clinical and neuropsychological assessment. We drew the lesion borders directly onto the original brain images of each patient, and plotted the lesions on anatomical atlases for grey and white matter. Results. Lesion locations were highly heterogeneous in our MN patients, and included frontal and parietal sites, basal ganglia and white matter. The only consistently damaged structure across all MN patients was the cingulum bundle, a major pathway of the medial motor system important for motor initiative, and a key connection with limbic structures crucial for motivational aspects of actions. Three MN patients with additional damage to lateral fronto-parietal networks had also signs of contralesional visual neglect. The cingulum bundle was intact in all the control patients with visual neglect or hemiplegia.Conclusions. Cingulum damage may induce MN through unilateral dysfunction of the medial motor system. Additional lateral fronto-parietal dysfunction can result in the association with visual neglect.
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.
Location of test bundle instrumentation and anticipated experimental values for the CFTL AG-1 bundle
International Nuclear Information System (INIS)
The placement of instrumentation within the Core Flow Test Loop (CFTL) AG-1 test section to meet the following objectives is described. The objectives are threefold: (1) to provide values for the evaluation of the performance of the test section, (2) to compare the experimental data with value determined by pretest calulations to indicate the approach to conditions that can lead to a bundle failure, and (3) to acquire data during testing that will form a data base for subsequent use in the verification of computational procedures used in the licensing of the Gas-Cooled Fast Reactor. Anticipated values for the various instruments have been determined using the computational procedure SAGAPO modified for the AG-1 geometry. These results are used as the basis for the specification of differential pressure cells and the range of readings anticipated from the thermocouples. Part of the results for the full-flow, full-power case is presented
Photochemical properties of mesophyll and bundle sheath chloroplasts of maize.
Bazzaz, M B; Govindjee
1973-09-01
Several photochemical and spectral properties of maize (Zea mays) bundle sheath and mesophyll chloroplasts are reported that provide a better understanding of the photosynthetic apparatus of C(4) plants. The difference absorption spectrum at 298 K and the fluorescence excitation and emission spectra of chlorophyll at 298 K and 77 K provide new information on the different forms of chlorophyll a in bundle sheath and mesophyll chloroplasts: the former contain, relative to short wavelength chlorophyll a forms, more long wavelength chlorophyll a form (e.g. chlorophyll a 693 and chlorophyll a 705) and less chlorophyll b than the latter. The degree of polarization of chlorophyll a fluorescence is 6% in bundle sheath and 4% in mesophyll chloroplasts. This result is consistent with the presence of relatively high amounts of oriented long wavelength forms of chlorophyll a in bundle sheath compared to mesophyll chloroplasts. The relative yield of variable, with respect to constant, chorophyll a fluorescence in mesophyll chloroplasts is more than twice that in bundle sheath chloroplast. Furthermore, the relative yield of total chlorophyll a fluorescence is 40% lower in bundle sheath compared to that in mesophyll chloroplasts. This is in agreement with the presence of the higher ratio of the weakly fluorescent pigment system I to pigment system II in bundle sheath than in mesophyll chloroplast. The efficiency of energy transfer from chlorophyll b and carotenoids to chlorophyll a are calculated to be 100 and 50%, respectively, in both types of chloroplasts. Fluorescence quenching of atebrin, reflecting high energy state of chloroplasts, is 10 times higher in mesophyll chloroplasts than in bundle sheath chloroplasts during noncyclic electron flow but is equal during cyclic flow. The entire electron transport chain is shown to be present in both types of chloroplasts, as inferred from the antagonistic effect of red (650 nm) and far red (710 nm) lights on the absorbance changes at
DEFF Research Database (Denmark)
Gammelgaard Nielsen, Anders
2011-01-01
MOTOR is the first assignment that students at Unit 1a of the School of Architecture are introduced to. The purpose of the assignment is to shake up the students and their preconceptions of what architec- ture is. This is done by introducing them to a working method that al- lows them to develop...... architecture that resides beyond their own imag- inative capabilities. In other words the core aim of the assignment is to equip students with an understand- ing that architecture can be devel- oped through a predetermined ge- neric process and that through this process opportunities exist to devel- op...... something original and genuine that decisively challenges the limits of the field of architecture. This un- derstanding is important if students are to avoid mimicking an existing world of imagery in architecture or fragments of it. The point of departure for the MO- TOR assignment is that a car engine...
Directory of Open Access Journals (Sweden)
Sandra Umeda Sasaki
2008-01-01
Full Text Available INTRODUCTION: Anterior cruciate ligament ruptures are frequent, especially in sports. Surgical reconstruction with autologous grafts is widely employed in the international literature. Controversies remain with respect to technique variations as continuous research for improvement takes place. One of these variations is the anatomical double bundle technique, which is performed instead of the conventional single bundle technique. More recently, there has been a tendency towards positioning the two bundles through double bone tunnels in the femur and tibia (anatomical reconstruction. OBJECTIVES: To compare, through biomechanical tests, the practice of anatomical double bundle anterior cruciate ligament reconstruction with a patellar graft to conventional single bundle reconstruction with the same amount of patellar graft in a paired experimental cadaver study. METHODS: Nine pairs of male cadaver knees ranging in age from 44 to 63 years were randomized into two groups: group A (single bundle and group B (anatomical reconstruction. Each knee was biomechanically tested under three conditions: intact anterior cruciate ligament, reconstructed anterior cruciate ligament, and injured anterior cruciate ligament. Maximum anterior dislocation, rigidity, and passive internal tibia rotation were recorded with knees submitted to a 100 N horizontal anterior dislocation force applied to the tibia with the knees at 30, 60 and 90 degrees of flexion. RESULTS: There were no differences between the two techniques for any of the measurements by ANOVA tests. CONCLUSION: The technique of anatomical double bundle reconstruction of the anterior cruciate ligament with bone-patellar tendon-bone graft has a similar biomechanical behavior with regard to anterior tibial dislocation, rigidity, and passive internal tibial rotation.
Hair-bundle friction from transduction channels' gating forces
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.
Pressure Loss across Tube Bundles in Two-phase Flow
Energy Technology Data Exchange (ETDEWEB)
Sim, Woo Gun; Banzragch, Dagdan [Hannam Univ., Daejon (Korea, Republic of)
2016-03-15
An analytical model was developed by Sim to estimate the two-phase damping ratio for upward two-phase flow perpendicular to horizontal tube bundles. The parameters of two-phase flow, such as void fraction and pressure loss evaluated in the model, were calculated based on existing experimental formulations. However, it is necessary to implement a few improvements in the formulations for the case of tube bundles. For the purpose of the improved formulation, we need more information about the two-phase parameters, which can be found through experimental test. An experiment is performed with a typical normal square array of cylinders subjected to the two-phase flow of air-water in the tube bundles, to calculate the two-phase Euler number and the two-phase friction multiplier. The pitch-to-diameter ratio is 1.35 and the diameter of cylinder is 18mm. Pressure loss along the flow direction in the tube bundles is measured with a pressure transducer and data acquisition system to calculate the two-phase Euler number and the two-phase friction multiplier. The void fraction model by Feenstra et al. is used to estimate the void fraction of the two-phase flow in tube bundles. The experimental results of the two phase friction multiplier and two-phase Euler number for homogeneous and non-homogeneous two-phase flows are compared and evaluated against the analytical results given by Sim's model.
Experimental study for convective heat transfer of staged tube bundles
International Nuclear Information System (INIS)
The lack of potable water is one of the most serious problems the world is facing at present. SMART which is a 330 MWt advanced integral PWR, was developed by the KAERI for electricity generation and seawater desalination. SMART adopted a passive system to enhance its safety. The passive system can passively remove a decay heat from a reactor core to an emergency cooldown tank through the heat exchanger. Tube bundles of the heat exchanger, which is submerged in an emergency cooldown tank, transfer heat to an emergency cooldown tank by natural circulation. Heat transfer tests for the upward straight tube bundle were performed to confirm the capability of the SMART design under natural circulation conditions. The heat transfer at the tube bundle was affected by the fluid temperature in the emergency cooldown tank and the radial location of tube bundle. However, it had nearly the same value at the inlet region regardless of the tube location. The average heat transfer at the tube bundle was slightly higher than that at the single tube. (author)
Thermal hydraulics of rod bundles: The effect of eccentricity
Energy Technology Data Exchange (ETDEWEB)
Chauhan, Amit K., E-mail: amit_fmlab@yahoo.co.in [Fluid Mechanics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India); Prasad, B.V.S.S.S., E-mail: prasad@iitm.ac.in [Thermal Turbomachines Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Patnaik, B.S.V., E-mail: bsvp@iitm.ac.in [Fluid Mechanics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India)
2013-10-15
Highlights: • Present CFD investigation explores, whole bundle eccentricity for the first time. • Fluid flow and thermal characteristics in various subchannels are analyzed. • Mass flux distribution is particularly analyzed to study eccentricity effect. • Higher eccentricity resulted in a shoot up in rod surface temperature distribution. • Both tangential and radial flow in rod bundles has resulted due to eccentricity. -- Abstract: The effect of eccentricity on the fluid flow and heat transfer through a 19-rod bundle is numerically carried out. When the whole bundle shifts downwards with respect to the outer (pressure) tube, flow redistribution happens. This in turn is responsible for changes in mass flux, pressure and differential flow development in various subchannels. The heat flux imposed on the surface of the fuel rods and the mass flux through the subchannels determines the coolant outlet temperatures. The simulations are performed for a coolant flow Reynolds number of 4 × 10{sup 5}. For an eccentricity value of 0.7, the mass flux in the bottom most subchannel (l) was found to decrease by 10%, while the surface temperature of the fuel rod in the vicinity of this subchannel increased by 250% at the outlet section. Parameters of engineering interest including skin friction coefficient, Nusselt number, etc., have been systematically explored to study the effect of eccentricity on the rod bundle.
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Multi-scale strain-stiffening of semiflexible bundle networks
Piechocka, I K; Broedersz, C P; Kurniawan, N A; MacKintosh, F C; Koenderink, G H
2015-01-01
Bundles of polymer filaments are responsible for the rich and unique mechanical behaviors of many biomaterials, including cells and extracellular matrices. In fibrin biopolymers, whose nonlinear elastic properties are crucial for normal blood clotting, protofibrils self-assemble and bundle to form networks of semiflexible fibers. Here we show that the extraordinary strain-stiffening response of fibrin networks is a direct reflection of the hierarchical architecture of the fibrin fibers. We measure the rheology of networks of unbundled protofibrils and find excellent agreement with an affine model of extensible wormlike polymers. By direct comparison with these data, we show that physiological fibrin networks composed of thick fibers can be modeled as networks of tight protofibril bundles. We demonstrate that the tightness of coupling between protofibrils in the fibers can be tuned by the degree of enzymatic intermolecular crosslinking by the coagulation Factor XIII. Furthermore, at high stress, the protofibri...
Magnetic Propulsion of Microswimmers with DNA-Based Flagellar Bundles.
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
Real Parabolic Vector Bundles over a Real Curve
Indian Academy of Sciences (India)
Sanjay Amrutiya
2014-02-01
We define real parabolic structures on real vector bundles over a real curve. Let $(X, _X)$ be a real curve, and let $S\\subset X$ be a non-empty finite subset of such that $_X(S) = S$. Let ≥ 2 be an integer. We construct an -fold cyclic cover : $Y→ X$ in the category of real curves, ramified precisely over each point of , and with the property that for any element of the Galois group , and any $y\\in Y$, one has $_Y(gy) = g^{-1}_Y(y)$. We established an equivalence between the category of real parabolic vector bundles on $(X,_X)$ with real parabolic structure over , all of whose weights are integral multiples of 1/, and the category of real -equivariant vector bundles on $(Y, _Y)$.
A class of Poisson Nijenhuis structures on a tangent bundle
Sarlet, W.; Vermeire, F.
2004-06-01
Equipping the tangent bundle TQ of a manifold with a symplectic form coming from a regular Lagrangian L, we explore how to obtain a Poisson-Nijenhuis structure from a given type (1, 1) tensor field J on Q. It is argued that the complete lift Jc of J is not the natural candidate for a Nijenhuis tensor on TQ, but plays a crucial role in the construction of a different tensor R, which appears to be the pullback under the Legendre transform of the lift of J to T*Q. We show how this tangent bundle view brings new insights and is capable also of producing all important results which are known from previous studies on the cotangent bundle, in the case when Q is equipped with a Riemannian metric. The present approach further paves the way for future generalizations.
Betti numbers of graded modules and cohomology of vector bundles
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.
Symposium on Singularities, Representation of Algebras, and Vector Bundles
Trautmann, Günther
1987-01-01
It is well known that there are close relations between classes of singularities and representation theory via the McKay correspondence and between representation theory and vector bundles on projective spaces via the Bernstein-Gelfand-Gelfand construction. These relations however cannot be considered to be either completely understood or fully exploited. These proceedings document recent developments in the area. The questions and methods of representation theory have applications to singularities and to vector bundles. Representation theory itself, which had primarily developed its methods for Artinian algebras, starts to investigate algebras of higher dimension partly because of these applications. Future research in representation theory may be spurred by the classification of singularities and the highly developed theory of moduli for vector bundles. The volume contains 3 survey articles on the 3 main topics mentioned, stressing their interrelationships, as well as original research papers.
Simulation of bundle test Quench-12 with integral code MELCOR
International Nuclear Information System (INIS)
The past NRI analyses cover the Quench-01, Quench-03 and Quench-06 with version MELCOR 1.8.5 (including reflood model), and Quench-01 and Quench-11 tests with the latest version MELCOR 1.8.6. The Quench-12 test is specific, because it has different bundle configuration related to the VVER bundle configuration with hexagonal grid of pins and also used E110 cladding material. Specificity of Quench-12 test is also in the used material of fuel rod cladding - E110. The test specificities are a reason for the highest concern, because the VVER reactors are operated in the Czech Republic. The new input model was developed with the taking into account all experience from previous simulations of the Quench bundle tests. The recent version MELCOR 1.8.6 YU2911 was used for the simulation with slightly modified ELHEAT package. Sensitivity studies on input parameters and oxidation kinetics were performed. (author)
Gradient Bundle Analysis: A Full Topological Approach to Chemical Bonding
Morgenstern, Amanda
2016-01-01
The "chemical bond" is a central concept in molecular sciences, but there is no consensus as to what a bond actually is. Therefore, a variety of bonding models have been developed, each defining the structure of molecules in a different manner with the goal of explaining and predicting chemical properties. This thesis describes the initial development of gradient bundle analysis (GBA), a chemical bonding model that creates a high resolution picture of chemical interactions within the charge density framework. GBA is based on concepts from the quantum theory of atoms in molecules (QTAIM), but uses a more complete picture of the topology and geometry of the electron charge density to understand and predict bonding interactions. Gradient bundles are defined as volumes bounded by zero-flux surfaces (ZFSs) in the gradient of the charge density with well-defined energies. The structure of gradient bundles provides an avenue for detecting the locations of valence electrons, which correspond to reactive regions in a ...
Lesson Eleven Transient and intermittent left bundle branch block
Institute of Scientific and Technical Information of China (English)
鲁端; 王劲
2004-01-01
@@ In transient left bundle branch block,normal intraventricular conduction subsequently returns,if only1temporarily.The condition has also been called paroxysmal,unstable,or temporary left bundle branch block. Its etiology is similar to that of the stable variety2, with the great majority of the patients having ischemic or hypertensive heart disease or both. Transient bundle branch block may complicate acute myocardial infarction or may occur during attacks of angina. It may appear during an episode of congestive heart failure and disappear with improvement of the cardiac status. Most patients eventually develop permanent block. Occasionally,however, the patient may revert to normal conduction even years after consistently demonstrating the block.
The Family Problem: Hints from Heterotic Line Bundle Models
Constantin, Andrei; Mishra, Challenger
2015-01-01
Within the class of heterotic line bundle models, we argue that N=1 vacua which lead to a small number of low-energy chiral families are preferred. By imposing an upper limit on the volume of the internal manifold, as required in order to obtain finite values of the four-dimensional gauge couplings, and validity of the supergravity approximation we show that, for a given manifold, only a finite number of line bundle sums are consistent with supersymmetry. By explicitly scanning over this finite set of line bundle models on certain manifolds we show that, for a sufficiently small volume of the internal manifold, the family number distribution peaks at small values, consistent with three chiral families. The relation between the maximal number of families and the gauge coupling is discussed, which hints towards a possible explanation of the family problem.
Magnetic Propulsion of Microswimmers with DNA-Based Flagellar Bundles.
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.
DTI Image Registration under Probabilistic Fiber Bundles Tractography Learning
Lei, Tao; Fan, Yangyu; Zhang, Xiuwei
2016-01-01
Diffusion Tensor Imaging (DTI) image registration is an essential step for diffusion tensor image analysis. Most of the fiber bundle based registration algorithms use deterministic fiber tracking technique to get the white matter fiber bundles, which will be affected by the noise and volume. In order to overcome the above problem, we proposed a Diffusion Tensor Imaging image registration method under probabilistic fiber bundles tractography learning. Probabilistic tractography technique can more reasonably trace to the structure of the nerve fibers. The residual error estimation step in active sample selection learning is improved by modifying the residual error model using finite sample set. The calculated deformation field is then registered on the DTI images. The results of our proposed registration method are compared with 6 state-of-the-art DTI image registration methods under visualization and 3 quantitative evaluation standards. The experimental results show that our proposed method has a good comprehensive performance.
Quillen Bundle and Geometric Prequantization of Non-Abelian Vortices on a Riemann Surface
Indian Academy of Sciences (India)
Rukmini Dey; Samir K Paul
2011-02-01
In this paper we prequantize the moduli space of non-abelian vortices. We explicitly calculate the symplectic form arising from 2 metric and we construct a prequantum line bundle whose curvature is proportional to this symplectic form. The prequantum line bundle turns out to be Quillen’s determinant line bundle with a modified Quillen metric. Next, as in the case of abelian vortices, we construct line bundles over the moduli space whose curvatures form a family of symplectic forms which are parametrized by $\\Psi_0$, a section of a certain bundle. The equivalence of these prequantum bundles are discussed.
The Determinant Bundle on the Moduli Space of Stable Triples over a Curve
Indian Academy of Sciences (India)
Indranil Biswas; N Raghavendra
2002-08-01
We construct a holomorphic Hermitian line bundle over the moduli space of stable triples of the form (1, 2, ), where 1 and 2 are holomorphic vector bundles over a fixed compact Riemann surface , and : 2 → 1 is a holomorphic vector bundle homomorphism. The curvature of the Chern connection of this holomorphic Hermitian line bundle is computed. The curvature is shown to coincide with a constant scalar multiple of the natural Kähler form on the moduli space. The construction is based on a result of Quillen on the determinant line bundle over the space of Dolbeault operators on a fixed ∞ Hermitian vector bundle over a compact Riemann surface.
Cellulosic Fibers: Effect of Processing on Fiber Bundle Strength
DEFF Research Database (Denmark)
Thygesen, Anders; Madsen, Bo; Thomsen, Anne Belinda;
2011-01-01
A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding, and cotto......A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding...
Stable bundles of rank 2 with 4 sections
Grzegorczyk, I; Newstead, P E
2010-01-01
This paper contains results on stable bundles of rank $2$ with space of sections of dimension $4$ on a smooth irreducible projective algebraic curve $C$. There is a known lower bound on the degree for the existence of such bundles; the main result of the paper is a geometric criterion for this bound to be attained. For a general curve $C$ of genus $10$, we show that the bound cannot be attained, but that there exist Petri curves of this genus for which the bound is sharp. We interpret the main results for various curves and in terms of Clifford indices and coherent systems.
Stable bundles of rank 2 with 4 sections
Grzegorczyk, I.; Mercat, V.; Newstead, P. E.
2010-01-01
This paper contains results on stable bundles of rank 2 with space of sections of dimension 4 on a smooth irreducible projective algebraic curve $C$. There is a known lower bound on the degree for the existence of such bundles; the main result of the paper is a geometric criterion for this bound to be attained. For a general curve $C$ of genus 10, we show that the bound cannot be attained, but that there exist Petri curves of this genus for which the bound is sharp. We interpret the main resu...
Normal Bundle of Rational Curves and Waring Decomposition
Bernardi, Alessandro
2012-01-01
The problem to determine the splitting of the normal bundle of rational curves has been considered in the 80s in a series of papers by Ghione and Sacchiero and in another series by Eisenbud and Van de Ven in the case of rational space curves. With our approach we are able to obtain results for curves enbedded in $\\bbP^m$ for $m\\geq 3$ we find an interesting interplay between the Waring decomposition and the splitting of the normal bundle.
Failure process of a bundle of plastic fibers
F. Raischel; Kun, F; Herrmann, H. J.
2006-01-01
We present an extension of fiber bundle models considering that failed fibers still carry a fraction $0 \\leq \\alpha \\leq 1$ of their failure load. The value of $\\alpha$ interpolates between the perfectly brittle failure $(\\alpha = 0)$ and perfectly plastic behavior $(\\alpha=1)$ of fibers. We show that the finite load bearing capacity of broken fibers has a substantial effect on the failure process of the bundle. In the case of global load sharing it is found that for $\\alpha \\to 1$ the macros...
Einstein Manifolds, Abelian Instantons, Bundle Reduction, and the Cosmological Constant
Soo, C P
2001-01-01
The anti-self-dual projection of the spin connections of certain four-dimensional Einstein manifolds can be Abelian in nature. These configurations signify bundle reductions. By a theorem of Kobayashi and Nomizu such a process is predicated on the existence of a covariantly constant field. It turns out that even without fundamental Higgs fields and other physical matter, gravitational self-interactions can generate this mechanism if the cosmological constant is non-vanishing. This article identifies the order parameter, and clarifies how these Abelian instanton solutions are associated with a Higgs triplet which causes the bundle reduction from SO(3) gauge group to U(1).
Chop-leach fuel bundle residues densification by melting
Energy Technology Data Exchange (ETDEWEB)
Nelson, R.G.; Griggs, B.
1976-11-01
Two melting processes were investigated for the densification of fuel bundle residues: Industoslag melting and graphite crucible melting. The Industoslag process, with prior decontamination and sorting, can produce ingots of Zircaloy, stainless steel and Inconel of a quality suitable for refabrication and reuse. The process can also melt oxidized mixtures of fuel bundle residues for direct storage. Eutectic mixtures of these materials can be melted in graphite at temperatures of 1300/sup 0/C. Hydrogen absorption experiments with the zirconium-rich alloys show the alloys to be potential tritium reservoirs. 13 figures.
ASSERT and COBRA predictions of flow distribution in vertical bundles
International Nuclear Information System (INIS)
COBRA and ASSERT are subchannel codes which compute flow and enthalpy distributions in rod bundles. COBRA is a well known code, ASSERT is under development at CRNL. This paper gives a comparison of the two codes with boiling experiments in vertical seven rod bundles. ASSERT predictions of the void distribution are shown to be in good agreement with reported experimental results, while COBRA predictions are unsatisfactory. The mixing models in both COBRA and ASSERT are briefly discussed. The reasons for the failure of COBRA-IV and the success of ASSERT in simulating the experiments are highlighted
Capillary Micro-Flow Through a Fiber Bundle(Ⅰ)
Institute of Scientific and Technical Information of China (English)
ZHU Ying-dan; WANG Ji-hui; TAN Hua; GAO Guo-qiang
2004-01-01
The present work considered the capillary micro-flow through a fiber bundle. The resin heights in the fiber bundle as a function of time were used to determine the experimental values of capillary pressure and the permeability by the nonlinear regression fitting method. The fitting curves showed a good agreement with experiments. However, these values of capillary pressure from short- time experiments were much lower than the theoretical results from the Yang-Laplace Equation. More accurate capillary pressure was predicted from the presented long-run experiment.
Phase Space Reduction of Star Products on Cotangent Bundles
Kowalzig, Niels; Neumaier, Nikolai; Pflaum, Markus J.
2004-01-01
In this paper we construct star products on Marsden-Weinstein reduced spaces in case both the original phase space and the reduced phase space are (symplectomorphic to) cotangent bundles. Under the assumption that the original cotangent bundle $T^*Q$ carries a symplectique structure of form $\\omega_{B_0}=\\omega_0 + \\pi^*B_0$ with $B_0$ a closed two-form on $Q$, is equipped by the cotangent lift of a proper and free Lie group action on $Q$ and by an invariant star product that admits a $G$-equ...
BUNDLE ADJUSTMENTS CCD CAMERA CALIBRATION BASED ON COLLINEARITY EQUATION
Institute of Scientific and Technical Information of China (English)
Liu Changying; Yu Zhijing; Che Rensheng; Ye Dong; Huang Qingcheng; Yang Dingning
2004-01-01
The solid template CCD camera calibration method of bundle adjustments based on collinearity equation is presented considering the characteristics of space large-dimension on-line measurement. In the method, a more comprehensive camera model is adopted which is based on the pinhole model extended with distortions corrections. In the process of calibration, calibration precision is improved by imaging at different locations in the whole measurement space, multi-imaging at the same location and bundle adjustments optimization. The calibration experiment proves that the calibration method is able to fulfill calibration requirement of CCD camera applied to vision measurement.
Reaction–diffusion model of hair-bundle morphogenesis
Jacobo, Adrian; Hudspeth, A. J.
2014-01-01
Our senses of hearing and balance rest upon the activity of hair cells, the ear’s sensory receptors. Each hair cell detects mechanical stimuli with its hair bundle, an organelle comprising 10–300 cylindrical, actin-filled stereocilia. A bundle’s structure is highly stereotyped: the stereocilia stand erect in a regular, hexagonal array and display a monotonic gradient in length along one axis. This precise organization is key to the operation of the hair bundle: mutations that disturb the morp...
Dialytic Separation of Bundled, Functionalized Carbon Nanotubes from Carbonaceous Impurities
Directory of Open Access Journals (Sweden)
J. Justin Mulvey
2014-11-01
Full Text Available Separating functionalized single-wall carbon nanotubes (SWCNTs from functionalized amorphous carbon is challenging, due to their polydispersity and similar physicochemical properties. We describe a single-step, dialytic separation method that takes advantage of the ability of heavily functionalized SWCNTs to bundle in a polar environment while maintaining their solubility. Experiments on functionalized SWCNTs were compared with functionalized, C60 fullerenes (buckyballs to probe the general applicability of the method and further characterize the bundling process. This approach may simultaneously be used to purify a functionalization reaction mixture of unreacted small molecules and of residual solvents, such as dimethylformamide.
High efficiency motors; Motores de alta eficiencia
Energy Technology Data Exchange (ETDEWEB)
Uranga Favela, Ivan Jaime [Energia Controlada de Mexico, S. A. de C. V., Mexico, D. F. (Mexico)
1992-12-31
This paper is a technical-financial study of the high efficiency and super-premium motors. As it is widely known, more than 60% of the electrical energy generated in the country is used for the operation of motors, in industry as well as in commerce. Therefore the importance that the motors have in the efficient energy use. [Espanol] El presente trabajo es un estudio tecnico-financiero de los motores de alta eficiencia y los motores super premium. Como es ampliamente conocido, mas del 60% de la energia electrica generada en el pais, es utilizada para accionar motores, dentro de la industria y el comercio. De alli la importancia que los motores tienen en el uso eficiente de la energia.
The effect of radial power profile of DUPIC bundle on CHF
International Nuclear Information System (INIS)
The axial and ring power profiles of DUPIC bundle are much different from those of reference 37-element fuel bundle since a DUPIC fuel bundle is re-fabricated using spent PWR fuel and 2-bundle shift refuelling scheme is proposed to CANDU-6 reactor. In case that the ring power profile of a fuel bundle is altered, the flow and enthalpy distribution of subchannels and the radial position of CHF occurrence will be changed. Similarly, the axial power profile of a fuel channel affects CHF and axial position of CHF occurrence as well as axial enthalpy, quality and pressure distribution. The ring power profile of the DUPIC bundle as increasing burnup is altered and flattened compared to 37-element bundle and each fuel bundle in a fuel channel has a different ring power profile from the other bundles at different axial position in the same fuel channel. Therefore, how to consider the burnup or ring power effect on CHF is very important to DUPIC thermalhydraulic analysis. At present study, thermalhydraulic analysis of the DUPIC bundle was performed in consideration of ring power profile effect on CHF. The subchannel enthalpy, mass flux and CHF distribution for 0 burnup to discharged burnup (18,000 MWD/THM) of DUPIC bundle were evaluated using ASSERT subchannel code. The results were compared to those of 37-element bundle and the compatability of DUPIC bundle with an existing CANDU-6 was presented in a CHF point of view
Study on Unigraphics Drawing Modeling Method for 37-Element and CANFLEX Fuel Bundle
Energy Technology Data Exchange (ETDEWEB)
Jeon, Yu Mi; Park, Joo Hwan
2010-03-15
The CANFLEX bundle contains 43 elements of two different diameters. It has two rings of small diameter elements on the outside, and eight elements (with diameter slightly larger than those in the standard 37-Element bundle) in the center. This larger number of small diameter elements on the outside of the CANFLEX bundle enhances thermo-hydraulic capability, resulting in a higher power capability and an improvement in operating safety margins. As a Result of advanced fuel design for CANFLEX fuel bundles, components consisting of fuel bundles are more complicated. Hence, the detailed modeling of components is inevitable in order to analyze the fuel performance by computational fluid dynamics. In this report, the basic design of the advanced fuel for CANDU reactors was carried out and the methodology for the modeling of fuel bundle were described. Firstly, the components consisting of fuel bundles were separately modeled and saved with different file names. The final feature of fuel bundle was accomplished by an assembling process of components. Since this report developed the modeling methodology based on the Unigraphics program, the basic explanations for the software were given first, and the complete modeling of 37-elements and CANFLEX fuel bundles were provided. The components of CANFLEX fuel bundles were also compared with that of 37-elements fuel bundles. Although, in this report, the modeling methodology is applied only to 37-elements and CANFLEX fuel bundles, this methodology may be applicable to the newly designed fuel bundles which are to be developed in the future
AdS 3-manifolds and Higgs bundles
DEFF Research Database (Denmark)
Alessandrini, Daniele; Li, Qiongling
2015-01-01
In this paper we investigate the relationships between closed AdS 3-manifolds and Higgs bundles. We have a new way to construct AdS structures that allows us to see many of their properties explicitly, for example we can recover the very recent formula by Tholozan for the volumes. We also find...
Signal Integrity Analysis in Single and Bundled Carbon Nanotube Interconnects
International Nuclear Information System (INIS)
Carbon nanotube (CN T) can be considered as an emerging interconnect material in current nano scale regime. They are more promising than other interconnect materials such as Al or Cu because of their robustness to electromigration. This research paper aims to address the crosstalk-related issues (signal integrity) in interconnect lines. Different analytical models of single- (SWCNT), double- (DWCNT), and multiwalled CNTs (MWCNT) are studied to analyze the crosstalk delay at global interconnect lengths. A capacitively coupled three-line bus architecture employing CMOS driver is used for accurate estimation of crosstalk delay. Each line in bus architecture is represented with the equivalent RLC models of single and bundled SWCNT, DWCNT, and MWCNT interconnects. Crosstalk delay is observed at middle line (victim) when it switches in opposite direction with respect to the other two lines (aggressors). Using the data predicted by ITRS 2012, a comparative analysis on the basis of crosstalk delay is performed for bundled SWCNT/DWCNT and single MWCNT interconnects. It is observed that the overall crosstalk delay is improved by 40.92% and 21.37% for single MWCNT in comparison to bundled SWCNT and bundled DWCNT interconnects, respectively.
Dendritic bundles, minicolumns, columns, and cortical output units
Directory of Open Access Journals (Sweden)
Giorgio Innocenti
2010-03-01
Full Text Available The search for the fundamental building block of the cerebral cortex has highlighted three structures, perpendicular to the cortical surface: i columns of neurons with radially invariant response properties, e.g., receptive field position, sensory modality, stimulus orientation or direction, frequency tuning etc. ii minicolumns of radially aligned cell bodies and iii bundles, constituted by the apical dendrites of pyramidal neurons with cell bodies in different layers. The latter were described in detail, and sometimes quantitatively, in several species and areas. It was recently suggested that the dendritic bundles consist of apical dendrites belonging to neurons projecting their axons to specific targets. We review the concept above and suggest that another structural and computational unit of cerebral cortex is the cortical output unit (COU, i.e. an assembly of bundles of apical dendrites and their parent cell bodies including each of the outputs to distant cortical or subcortical structures, of a given cortical locus (area or part of an area. This somato-dendritic assembly receives inputs some of which are common to the whole assembly and determine its radially invariant response properties, others are specific to one or more dendritic bundles, and determine the specific response signature of neurons in the different cortical layers and projecting to different targets.
A Method of Assembling Compact Coherent Fiber-Optic Bundles
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.
Almost Lie structures on an anchored Banach bundle
Cabau, Patrick
2011-01-01
Under appropriate assumptions, we generalize the concept of linear almost Poisson struc- tures, almost Lie algebroids, almost differentials in the framework of Banach anchored bundles and the relation between these objects. We then obtain an adapted formalism for mechanical systems which is illustrated by the evolutionary problem of the "Hilbert snake"
Rigidity of Minimal Submanifolds with Flat Normal Bundle
Indian Academy of Sciences (India)
Hai-Ping Fu
2010-09-01
Let $M^n(n≥ 3)$ be an -dimensional complete immersed $\\frac{n-2}{n}$-superstable minimal submanifold in an $(n+p)$-dimensional Euclidean space $\\mathbb{R}^{n+p}$ with flat normal bundle. We prove that if the second fundamental form of satisfies some decay conditions, then is an affine plane or a catenoid in some Euclidean subspace.
Assembly and operation experience of EVA II steam reforming bundle
International Nuclear Information System (INIS)
The main test component of the experimental facility EVA-II/ADAM-II is a helium heated steam reformer bundle with 30 tubes. The tubes are filled with a catalyst of raschig ring type. The main test of the component were related to the power dependence. A series of experiment dealt with the influence of steam/methane ratio on the carbon deposit formation
Euler-Lagrange Forms and Cohomology Groups on Jet Bundles
Institute of Scientific and Technical Information of China (English)
CHEN Jing-Bo
2005-01-01
@@ Using the language of jet bundles, we generalize the definitions of Euler-Lagrange one-form and the associated cohomology which were introduced by Guo et al. [Commun. Theor. Phys. 37(2002)1]. Continuous and discreteLagrange mechanics and field theory are presented. Higher order Euler-Lagrange cohomology groups are also introduced.
Quantum nonsymmetric gravity and the superfiber bundle formalism
International Nuclear Information System (INIS)
The formalism of the principal super fiber-bundle is applied to quantum Nonsymmetric gravitational theory. It is shown that the metric and Fadeev-Popov fields arise as superfield components of the super connection. Moreover the BRST and anti-BRST transformations are shown to be the gauge transformations of the parameters of the ghost and anti-ghost superfields. (authors)
Quantum Nonsymmetric Gravity and The Superfiber Bundle Formalism
Mebarki, N
1999-01-01
The formalism of the principal superfiber-bundle is applied to quantum Nonsymmetric gravitationl theory. It is shown that the metric and Faddev-Popov fields arise as superfields components of the superconnection. Moreover,the BRST and anti-BRST transformations are shown to be the gauge transformations of parameters the ghost and anti-ghost superfields.
Elliptic open books on torus bundles over the circle
Etgü, Tolga
2006-01-01
As an application of the construction of open books on plumbed 3-manifolds, we construct elliptic open books on torus bundles over the circle. In certain cases these open books are compatible with Stein fillable contact structures and have minimal genus.
Heat transfer and fluid friction in bundles of twisted tubes
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.
Self-adjointness of the Gaffney Laplacian on Vector Bundles
Energy Technology Data Exchange (ETDEWEB)
Bandara, Lashi, E-mail: lashi.bandara@chalmers.se [Chalmers University of Technology and University of Gothenburg, Mathematical Sciences (Sweden); Milatovic, Ognjen, E-mail: omilatov@unf.edu [University of North Florida, Department of Mathematics and Statistics (United States)
2015-12-15
We study the Gaffney Laplacian on a vector bundle equipped with a compatible metric and connection over a Riemannian manifold that is possibly geodesically incomplete. Under the hypothesis that the Cauchy boundary is polar, we demonstrate the self-adjointness of this Laplacian. Furthermore, we show that negligible boundary is a necessary and sufficient condition for the self-adjointness of this operator.
Multicell slug flow heat transfer analysis of finite LMFBR bundles
Energy Technology Data Exchange (ETDEWEB)
Yeung, M.K.; Wolf, L.
1978-12-01
An analytical two-dimensional, multi-region, multi-cell technique has been developed for the thermal analysis of LMFBR rod bundles. Local temperature fields of various unit cells were obtained for 7, 19, and 37-rod bundles of different geometries and power distributions. The validity of the technique has been verified by its excellent agreement with the THTB calculational result. By comparing the calculated fully-developed circumferential clad temperature distribution with those of the experimental measurements, an axial correction factor has been derived to account for the entrance effect for practical considerations. Moreover, the knowledge of the local temperature field of the rod bundle leads to the determination of the effective mixing lengths L/sub ij/ for adjacent subchannels of various geometries. It was shown that the implementation of the accurately determined L/sub ij/ into COBRA-IIIC calculations has fairly significant effects on intersubchannel mixing. In addition, a scheme has been proposed to couple the 2-D distributed and lumped parameter calculation by COBRA-IIIC such that the entrance effect can be implanted into the distributed parameter analysis. The technique has demonstrated its applicability for a 7-rod bundle and the results of calculation were compared to those of three-dimensional analyses and experimental measurements.
Coupling Systems of Five CARA Fuel Bundles for Atucha I
International Nuclear Information System (INIS)
This paper describe the mechanical design of two options for the coupling systems of five CARA fuel bundles, to be used in the Atucha I nuclear power plant. These systems will be hydraulic tested in a low pressure loop to know their hydraulic loss of pressure
Fission yeast Scp3 potentially maintains microtubule orientation through bundling.
Directory of Open Access Journals (Sweden)
Kanako Ozaki
Full Text Available 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.
Frame-independent mechanics:geometry on affine bundles
Grabowska, K.; Grabowski, J.; Urbanski, P.
2005-01-01
Main ideas of the differential geometry on affine bundles are presented. Affine counterparts of Lie algebroid and Poisson structures are introduced and discussed. The developed concepts are applied in a frame-independent formulation of the time-dependent and the Newtonian mechanics.
MYOCARDIAL DEFORMATION AND COMPLETE LEFT BUNDLE BRANCH BLOCK
Directory of Open Access Journals (Sweden)
E. N. Pavlyukova
2015-12-01
Full Text Available Tissue Doppler imaging is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular systolic and diastolic function. Over the last 10 years, myocardial deformation imaging has become possible initially with tissue Doppler , and more recently with myocardial speckle-tracking using 2D echocardiography. Unlike simple tissue velocity measurements, deformation measurements are specific for the region of interest. Strain rate or strain measurements have been used as sensitive indicators for subclinical diseases, and it is the most widely used tool to assess mechanical dyssynchrony. Left bundle branch block is a frequent, etiologically heterogeneous, clinically hostile and diagnostically challenging entity. About 2% of patients underwent cardiac stress testing show stable or intermittent left bundle branch block. Presence of left bundle branch block is associated with a lower and slower diastolic coronary flow velocity especially during hyperemia. Stress echocardiography is the best option for the diagnosis of ischemic heart disease, albeit specificity and sensitivity reduce in patients with left bundle branch block in the territory of left anterior descending artery in presence of initial septum dyskinesia.
Regularity for The CR Vector Bundle Problem I
Gong, Xianghong; Webster, S. M.
2009-01-01
We give a new solution to the local integrability problem for CR vector bundles over strictly pseudoconvex real hypersurfaces of dimension seven or greater. It is based on a KAM rapid convergence argument and avoids the previous more difficult Nash-Moser methods. The solution is sharp as to H\\"older continuity.
A note on stochastic calculus in vector bundles
Catuogno, Pedro J; Ruffino, Paulo R
2011-01-01
The aim of these notes is to relate covariant stochastic integration in a vector bundle $E$ (as in Norris \\cite{Norris}) with the usual Stratonovich calculus via the connector $\\K:TE \\rightarrow E$ (cf. e.g. Paterson \\cite{Paterson} or Poor \\cite{Poor}) which carries the connection dependence.
Negotiating over bundles and prices using aggregate knowledge
Somefun, D.J.A.; Klos, T.B.; La Poutré, J.A.
2004-01-01
Combining two or more items and selling them as one good, a practice called bundling, can be a very effective strategy for reducing the costs of producing, marketing, and selling goods. In this paper, we consider a form of multi-issue negotiation where a shop negotiates both the contents and the pri
Product Bundling and Shared Information Goods: A Pricing Exercise
Morrison, William G.
2016-01-01
In this article, the author describes an exercise in which two pricing problems (product bundling and the sharing of digital information goods) can be understood using the same analytical approach. The exercise allows students to calculate the correct numerical answers with relative ease, while the teaching plan demonstrates the importance of the…
Exposure Control Using Adaptive Multi-Stage Item Bundles.
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…
Motor Priming in Neurorehabilitation
Stoykov, Mary Ellen; Madhavan, Sangeetha
2015-01-01
Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance. Of the numerous motor priming paradigms under investigation, only a few ...
Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Progress report
Energy Technology Data Exchange (ETDEWEB)
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)
2010-02-24
... Price Index Adjustments for Expenditure Limitations and Lobbyist Bundling Disclosure Threshold AGENCY: Federal Election Commission. ACTION: Notice of adjustments to expenditure limitations and lobbyist... Commission'') is adjusting certain expenditure limitations and the lobbyist bundling disclosure threshold...
2012-02-21
... Price Index Adjustments for Expenditure Limitations and Lobbyist Bundling Disclosure Threshold AGENCY: Federal Election Commission. ACTION: Notice of adjustments to expenditure limitations and lobbyist... Commission'') is adjusting certain expenditure limitations and the lobbyist bundling disclosure threshold...
A comprehensive comparison on vibration and heat transfer of two elastic heat transfer tube bundles
Institute of Scientific and Technical Information of China (English)
闫柯; 葛培琪; 翟强
2015-01-01
Elastic heat transfer tube bundles are widely used in the field of flow-induced vibration heat transfer enhancement. Two types of mainly used tube bundles, the planar elastic tube bundle and the conical spiral tube bundle were comprehensively compared in the condition of the same shell side diameter. The natural mode characteristics, the effect of fluid−structure interaction, the stress distribution, the comprehensive heat transfer performance and the secondary fluid flow of the two elastic tube bundles were all concluded and compared. The results show that the natural frequency and the critical velocity of vibration buckling of the planar elastic tube bundle are larger than those of the conical spiral tube bundle, while the stress distribution and the comprehensive heat transfer performance of the conical spiral tube bundle are relatively better.
Sanchez, Tim
This thesis discusses circularization and supercoiling of actin biofilaments, as well as the various examples of self-organization observed in a simple non-equilibrium system of microtubules, motor clusters, and a depletion agent (PEG). When the ends of an actin filament approach each other, annealing can occur, resulting in the assumption of a circular conformation. In order to facilitate this experimentally, we dramatically reduce the space available for the ends to explore by confining the filaments to a quasi-2D region. This is accomplished through the use of a depletion attraction. In addition to the pronounced effects of this topological ring constraint on the statistical fluctuations of the filaments, we also observe a spontaneous supercoiling transition in fluorescently labeled actin rings that is directly driven by illumination. To better understand this transition in natural twist, we investigate real-time twist of a filament trapped between two beads, held by optical traps. The main focus of this graduate work was on the behavior of non-equilibrium in vitro mixtures of microtubules, kinesin motor clusters, and a depletion agent. We observed several striking and distinct examples of self-organization on near-macroscopic length scales, due to the interactions of very simple components. First we investigate the driving mechanism behind the beating of biological cilia and flagella, and find that this beating functionality can be reproduced in our vastly simpler system. This occurs only when minimalist components are reconstituted: motors, biofilaments, elastic links to hold the filaments together, and a basal attachment. Beyond the cooperativity of the motors to produce oscillatory beating in individual bundles, we also observe that active bundles in close proximity can synchronize their beating to produce stable, periodic metachronal waves that propagate along the bundle array. By changing only the length distribution of the microtubules in our system, we
Twisted Partial Actions, A Classification of Stable C*-Algebraic Bundles (Preliminary Version)
Exel, Ruy
1994-01-01
We introduce the notion of continuous twisted partial actions of a locally compact group on a C*-algebra. With such, we construct an associated C*-algebraic bundle called the semidirect product bundle. Our main theorem shows that, given any C*-algebraic bundle which is second countable and whose unit fiber algebra is stable, there is a continuous twisted partial action of the base group on the unit fiber algebra, whose associated semidirect product bundle is isomorphic to the given one.
Equilibrium Bundle Size of Rodlike Polyelectrolytes with Counterion-Induced Attractive Interactions
Henle, Mark L.; Pincus, Philip A.
2004-01-01
Multivalent counterions can induce an effective attraction between like-charged rodlike polyelectrolytes, leading to the formation of polelectrolyte bundles. In this paper, we calculate the equilibrium bundle size using a simple model in which the attraction between polyelectrolytes (assumed to be pairwise additive) is treated phenomenologically. If the counterions are point-like, they almost completely neutralize the charge of the bundle, and the equilibrium bundle size diverges. When the co...
On the Topology of Real Bundle Pairs over Nodal Symmetric Surfaces
Georgieva, Penka
2015-01-01
We give an alternative argument for the classification of real bundle pairs over smooth symmetric surfaces and extend this classification to nodal symmetric surfaces. We also classify the homotopy classes of automorphisms of real bundle pairs over symmetric surfaces. The two statements together describe the isomorphisms between real bundle pairs over symmetric surfaces up to deformation.
Semistability of Certain Bundles on Second Symmetric Power of a Curve
Dan, Krishanu; Pal, Sarbeswar
2015-01-01
Let $C$ be a smooth irreducible projective curve and $E$ be a rank 2 stable vector bundle on $C$. Then one can associate a rank 4 vector bundle $\\mathcal{F}_2(E)$ on $S^2(C)$, second symmetric power of $C$. Our goal in this article is to study semistability of this bundle.
Chalmers, B J
2013-01-01
Electric Motor Handbook aims to give practical knowledge in a wide range of capacities such as plant design, equipment specification, commissioning, operation and maintenance. The book covers topics such as the modeling of steady-state motor performance; polyphase induction, synchronous, and a.c. commutator motors; ambient conditions, enclosures, cooling and loss dissipation; and electrical supply systems and motor drives. Also covered are topics such as variable-speed drives and motor control; materials and motor components; insulation types, systems, and techniques; and the installation, sit
Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)
2011-01-01
A directed flux motor described utilizes the directed magnetic flux of at least one magnet through ferrous material to drive different planetary gear sets to achieve capabilities in six actuated shafts that are grouped three to a side of the motor. The flux motor also utilizes an interwoven magnet configuration which reduces the overall size of the motor. The motor allows for simple changes to modify the torque to speed ratio of the gearing contained within the motor as well as simple configurations for any number of output shafts up to six. The changes allow for improved manufacturability and reliability within the design.
Handbook on linear motor application
International Nuclear Information System (INIS)
This book guides the application for Linear motor. It lists classification and speciality of Linear Motor, terms of linear-induction motor, principle of the Motor, types on one-side linear-induction motor, bilateral linear-induction motor, linear-DC Motor on basic of the motor, linear-DC Motor for moving-coil type, linear-DC motor for permanent-magnet moving type, linear-DC motor for electricity non-utility type, linear-pulse motor for variable motor, linear-pulse motor for permanent magneto type, linear-vibration actuator, linear-vibration actuator for moving-coil type, linear synchronous motor, linear electromagnetic motor, linear electromagnetic solenoid, technical organization and magnetic levitation and linear motor and sensor.
Frobenius Pull Backs of Vector Bundles in Higher Dimensions
Indian Academy of Sciences (India)
V Trivedi
2012-11-01
We prove that for a smooth projective variety of arbitrary dimension and for a vector bundle over , the Harder–Narasimhan filtration of a Frobenius pull back of is a refinement of the Frobenius pull back of the Harder–Narasimhan filtration of , provided there is a lower bound on the characteristic (in terms of rank of and the slope of the destabilizing sheaf of the cotangent bundle of ). We also recall some examples, due to Raynaud and Monsky, to show that some lower bound on is necessary. We also give a bound on the instability degree of the Frobenius pull back of in terms of the instability degree of and well defined invariants of .
Dimer model for Tau proteins bound in microtubule bundles
Hall, Natalie; Kluber, Alexander; Hayre, N. Robert; Singh, Rajiv; Cox, Daniel
2013-03-01
The microtubule associated protein tau is important in nucleating and maintaining microtubule spacing and structure in neuronal axons. Modification of tau is implicated as a later stage process in Alzheimer's disease, but little is known about the structure of tau in microtubule bundles. We present preliminary work on a proposed model for tau dimers in microtubule bundles (dimers are the minimal units since there is one microtubule binding domain per tau). First, a model of tau monomer was created and its characteristics explored using implicit solvent molecular dynamics simulation. Multiple simulations yield a partially collapsed form with separate positively/negatively charged clumps, but which are a factor of two smaller than required by observed microtubule spacing. We argue that this will elongate in dimer form to lower electrostatic energy at a cost of entropic ``spring'' energy. We will present preliminary results on steered molecular dynamics runs on tau dimers to estimate the actual force constant. Supported by US NSF Grant DMR 1207624.
Balanced metrics for vector bundles and polarised manifolds
DEFF Research Database (Denmark)
Garcia Fernandez, Mario; Ross, Julius
2012-01-01
We consider a notion of balanced metrics for triples (X, L, E) which depend on a parameter α, where X is smooth complex manifold with an ample line bundle L and E is a holomorphic vector bundle over X. For generic choice of α, we prove that the limit of a convergent sequence of balanced metrics...... leads to a Hermitian-Einstein metric on E and a constant scalar curvature Kähler metric in c_1(L). For special values of α, limits of balanced metrics are solutions of a system of coupled equations relating a Hermitian-Einstein metric on E and a Kähler metric in c1(L). For this, we compute the top two...
Nuclear spin relaxation due to random motion of vortex bundles
International Nuclear Information System (INIS)
The dependence of nuclear-spin-relaxation rate T1 on NMR resonant frequency for a layered superconducting sample has been analyzed theoretically. In the considered arrangement the Zeeman field has been applied in the plane of superconducting layers while the relaxation was due to interactions between the spin systems and moving flux bundles, created by the transport current flowing along superconducting layers. It has been found that the functional form of a dependence of spin-relaxation rate on the Zeeman field has two components, a Lorentzian and an oscillatory one. The characteristic rolloff frequency of the Lorentzian component depends on the pinning properties of the sample. The period of oscillations of the oscillatory component is of the order of the inverse of interaction time of flowing flux bundles with a probe nucleus. copyright 1996 The American Physical Society
On phenomena of turbulent flow through rod bundles
International Nuclear Information System (INIS)
Experimental studies have shown that the axial and azimuthal turbulence intensities in the gap regions of rod bundles increase strongly with decreasing rod spacing; the fluctuating velocities in the axial and azimuthal directions have a quasi-periodic behavior. To determine the origin of this phenomenon and its characteristic as a function of the geometry and the Reynolds number, an experimental investigation was performed on the turbulent flow in several rod bundles with different aspect ratios (P/D, W/D). Hot-wires and microphones were used for the measurements of velocity and wall pressure fluctuations. The data were evaluated to obtain spectra as well as auto and cross correlations. Based on the results, a phenomenological model is proposed to explain this phenomenon. By means of the model, the mass exchange between neighbouring subchannels is explained. (orig.)
A class of recursion operators on a tangent bundle
Vermeire, F.; Sarlet, W.; Crampin, M.
2006-06-01
We generalize the construction of a class of type (1, 1) tensor fields R on a tangent bundle which was introduced in a preceding paper. The generalization comes from the fact that, apart from a given Lagrangian, the further data consist of a type (1, 1) tensor J along the tangent bundle projection τ: TQ →Q, rather than a tensor on Q. The main features under investigation are two kinds of recursion properties of R, namely its potential invariance under the flow of the given dynamics and the property of having vanishing Nijenhuis torsion. The theory is applied, in particular, to the case of second-order dynamics coming from a Finsler metric.
A class of recursion operators on a tangent bundle
Energy Technology Data Exchange (ETDEWEB)
Vermeire, F [Department of Mathematical Physics and Astronomy, Ghent University, Krijgslaan 281, B-9000 Ghent (Belgium); Sarlet, W [Department of Mathematical Physics and Astronomy, Ghent University, Krijgslaan 281, B-9000 Ghent (Belgium); Crampin, M [Department of Mathematical Physics and Astronomy, Ghent University, Krijgslaan 281, B-9000 Ghent (Belgium)
2006-06-09
We generalize the construction of a class of type (1, 1) tensor fields R on a tangent bundle which was introduced in a preceding paper. The generalization comes from the fact that, apart from a given Lagrangian, the further data consist of a type (1, 1) tensor J along the tangent bundle projection {tau}: TQ {yields}Q, rather than a tensor on Q. The main features under investigation are two kinds of recursion properties of R, namely its potential invariance under the flow of the given dynamics and the property of having vanishing Nijenhuis torsion. The theory is applied, in particular, to the case of second-order dynamics coming from a Finsler metric.
Pressure effects on single wall carbon nanotube bundles
Energy Technology Data Exchange (ETDEWEB)
Teredesai, P.V. [Indian Inst. of Science, Bangalore (India). Dept. of Physics; Sood, A.K. [Indian Inst. of Science, Bangalore (India). Dept. of Physics; Chemistry and Physics of Materials Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur Campus, Jakkur (India); Sharma, S.M.; Karmakar, S.; Sikka, S.K. [High Pressure Physics Div., Bhabha Atomic Research Center, Mumbai (India); Govindaraj, A.; Rao, C.N.R. [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur Campus, Jakkur (India)
2001-01-01
We report high pressure Raman studies on single wall carbon nanotube bundles under hydrostatic conditions using two different pressure transmitting media, alcohol mixture and pure water. The radial and tangential modes show a blue shift when SWNT bundle is immersed in the liquids at ambient pressures. The pressure dependence of the radial modes is the same in both liquids. However, the pressure derivatives d{omega}/dP of the tangential modes are slightly higher for the water medium. Raman results are compared with studies under non-hydrostatic conditions and with recent high-pressure X-ray studies. It is seen that the mode frequencies of the recovered sample after pressure cycling from 26 GPa are downshifted by {proportional_to}7-10 cm{sup -1} as compared to the starting sample. (orig.)
An improved partial bundle method for linearly constrained minimax problems
Directory of Open Access Journals (Sweden)
Chunming Tang
2016-02-01
Full Text Available In this paper, we propose an improved partial bundle method for solving linearly constrained minimax problems. In order to reduce the number of component function evaluations, we utilize a partial cutting-planes model to substitute for the traditional one. At each iteration, only one quadratic programming subproblem needs to be solved to obtain a new trial point. An improved descent test criterion is introduced to simplify the algorithm. The method produces a sequence of feasible trial points, and ensures that the objective function is monotonically decreasing on the sequence of stability centers. Global convergence of the algorithm is established. Moreover, we utilize the subgradient aggregation strategy to control the size of the bundle and therefore overcome the difficulty of computation and storage. Finally, some preliminary numerical results show that the proposed method is effective.
Attribute-based edge bundling for visualizing social networks
Guo, Lin; Zuo, Wanli; Peng, Tao; Adhikari, Binod Kumar
2015-11-01
Most nodes in complex networks have multiple attributes, which make them hard to analyze. Because general edge bundling algorithms fail to handle complex networks as a result of their intricate features, network simplification is extremely important. This paper proposes an attribute-based edge bundling algorithm that displays similar edges in nearby locations. Meanwhile, by analyzing complex networks at a community level, the overlapping clustering of nodes is well implemented, and better clustering effects can be achieved by grouping similar edges together. On the basis of datasets with different types and sizes, the experiments illustrate the simplification degree of the intricate graphs created by the algorithm proposed, which outperforms established competitors in correctness and effectiveness.
Field emission from nanotube bundle emitters at low fields
Energy Technology Data Exchange (ETDEWEB)
Wang, Q.H.; Corrigan, T.D.; Dai, J.Y.; Chang, R.P. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Krauss, A.R. [Materials Science and Chemistry Divisions, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
1997-06-01
The fabrication of nanotube field emitters with an onset field as low as 0.8 V/{mu}m is described and the low-field electron emission mechanism is discussed. These emitters are made using nanotube cathode deposit with the addition of epoxy resin. The preferred orientation of nanotubes in nanotube bundles of the deposit is preserved. The nanotube tips are sharpened by exposing the nanotube bundle surface to a microwave oxygen plasma. The local-field enhancement factor is estimated to be 8000 by using the Fowler{endash}Nordheim equation. The low onset field is attributed to the well-distributed, highly orientated sharp tips at the sample surface. {copyright} {ital 1997 American Institute of Physics.}
CAT reconstruction and potting comparison of a LMFBR fuel bundle
International Nuclear Information System (INIS)
A standard Liquid Metal Fast Breeder Reactor (LMFBR) subassembly used in the Experimental Breeder Reactor II (EBR-II) was investigated, by remote techniques, for fuel bundle distortion by both nondestructive and destructive methods, and the results from both methods were compared. The non-destructive method employed neutron tomography to reconstruct the locations of fuel elements through the use of a maximum entropy reconstruction algorithm known as MENT. The destructive method consisted of ''potting'' (a technique that embeds and permanently fixes the fuel elements in a solid matrix) the subassembly, and then cutting and polishing the individual sections. The comparison indicated that the tomography reconstruction provided good results in describing the bundle geometry and spacer-wire locations, with the overall resolution being on the order of a spacer-wire diameter. A dimensional consistency check indicated that the element and spacer-wire dimensions were accurately reproduced in the reconstruction
Persistence Length and Nanomechanics of Random Bundles of Nanotubes
Energy Technology Data Exchange (ETDEWEB)
Yakobson, Boris I. [Rice University, Department of Mechanical Engineering and Materials Science, Department of Chemistry, and Center for Nanoscale Science and Technology (United States)], E-mail: biy@rice.edu; Couchman, Luise S. [Naval Research Laboratory, Code 7130 (United States)
2006-02-15
A connection between the stiffness of carbon nanotubes (CNT) and their mesoscopic physical behaviour is presented. Persistence lengths of CNT and bundles are calculated and shown to be in macroscopic range (0.03-1 mm for an individual tube), exceeding by many orders of magnitude the typical diameters (around 1-3 nm). Consequently, thermal fluctuations can be neglected when scaling analysis is applied to randomly packed (as produced) CNT network, leading to an approximate equation of state for such material. Beyond the linear elasticity, the outmost CNT are shown to gradually split from the bent bundles; this permits access of solvent or reacting species to the CNT walls, an important mechanism promoting solubilization and chemical functionalization of nanotubes.
Multiplexed holographic memory by use of fiber bundle referencing
Zhang, Jiasen; Aruga, Tadashi
2005-04-01
We propose a volume holographic storage technique, in which a fiber bundle is used to guide the reference beam. Multiplexing is implemented by changing the incident direction of the laser beam upon the fiber bundle in the reference arm. In the technique, we make the system more compact by using a wedge prism to change the direction of the laser beam. This method has a large accessible angular scanning range and a large geometric storage bandwidth. Multiple images are stored in a LiNbO3:Fe crystal with an angular separation of 0.05° between successive holograms using a wedge prism with a deviation angle of 8°. This method is useful as a new image storage technique because of its compactness and simplicity.
Infinitesimal moduli of G2 holonomy manifolds with instanton bundles
de la Ossa, Xenia; Svanes, Eirik Eik
2016-01-01
We describe the infinitesimal moduli space of pairs $(Y, V)$ where $Y$ is a manifold with $G_2$ holonomy, and $V$ is a vector bundle on $Y$ with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. Employing the canonical $G_2$ cohomology $H^*_{{\\check{\\rm d}}_E}(Y,E)$ developed by Reyes-Carri\\'on and Fern\\'andez and Ugarte, we show that the moduli space decomposes into the sum of the bundle moduli $H^1_{{\\check{\\rm d}}_A}(Y,{\\rm End}(V))$ plus the moduli of the $G_2$ structure preserving the instanton condition. The latter piece is contained in $H^1_{{\\check{\\rm d}}_\
The special linear version of the projective bundle theorem
Ananyevskiy, Alexey
2012-01-01
A special linear Grassmann variety SGr(k,n) is the complement to the zero section of the determinant of the tautological vector bundle over Gr(k,n). For a representable ring cohomology theory A(-) with a special linear orientation and invertible stable Hopf map \\eta, including Witt groups and MSL[\\eta^{-1}], we have A(SGr(2,2n+1))=A(pt)[e]/(e^{2n}), and A(SGr(2,2n)) is a truncated polynomial algebra in two variables over A(pt). A splitting principle for such theories is established. We use the computations for the special linear Grassmann varieties to calculate A(BSL_n) in terms of the homogeneous power series in certain characteristic classes of the tautological bundle.
Wu, Jing; Wang, Heng; Guo, Xuan; Chen, Jiong
2016-08-15
The actin bundle is an array of linear actin filaments cross-linked by actin-bundling proteins, but its assembly and dynamics are not as well understood as those of the branched actin network. Here we used the Drosophila bristle as a model system to study actin bundle formation. We found that cofilin, a major actin disassembly factor of the branched actin network, promotes the formation and positioning of actin bundles in the developing bristles. Loss of function of cofilin or AIP1, a cofactor of cofilin, each resulted in increased F-actin levels and severe defects in actin bundle organization, with the defects from cofilin deficiency being more severe. Further analyses revealed that cofilin likely regulates actin bundle formation and positioning by the following means. First, cofilin promotes a large G-actin pool both locally and globally, likely ensuring rapid actin polymerization for bundle initiation and growth. Second, cofilin limits the size of a nonbundled actin-myosin network to regulate the positioning of actin bundles. Third, cofilin prevents incorrect assembly of branched and myosin-associated actin filament into bundles. Together these results demonstrate that the interaction between the dynamic dendritic actin network and the assembling actin bundles is critical for actin bundle formation and needs to be closely regulated.
Linear duals of graded bundles and higher analogues of (Lie) algebroids
Bruce, Andrew James; Grabowska, Katarzyna; Grabowski, Janusz
2016-03-01
Graded bundles are a class of graded manifolds which represent a natural generalisation of vector bundles and include the higher order tangent bundles as canonical examples. We present and study the concept of the linearisation of graded bundle which allows us to define the notion of the linear dual of a graded bundle. They are examples of double structures, graded-linear (GL) bundles, including double vector bundles as a particular case. On GL-bundles we define what we shall call weighted algebroids, which are to be understood as algebroids in the category of graded bundles. They can be considered as a geometrical framework for higher order Lagrangian mechanics. Canonical examples are reductions of higher tangent bundles of Lie groupoids. Weighted algebroids represent also a generalisation of VB-algebroids as defined by Gracia-Saz & Mehta and the LA-bundles of Mackenzie. The resulting structures are strikingly similar to Voronov's higher Lie algebroids, however our approach does not require the initial structures to be defined on supermanifolds.
Chronic vocal tic disorder; Tic - chronic motor tic disorder ... Chronic motor tic disorder is more common than Tourette syndrome . Chronic tics may be forms of Tourette syndrome. Tics usually start ...
... figure out the child's developmental age. Children develop fine motor skills over time, by practicing and being taught. To have fine motor control, children need: Awareness and planning Coordination ...
Analysis of Subchannel and Rod Bundle PSBT Experiments with CATHARE 3
Directory of Open Access Journals (Sweden)
M. Valette
2012-01-01
Full Text Available This paper presents the assessment of CATHARE 3 against PWR subchannel and rod bundle tests of the PSBT benchmark. Noticeable measurements were the following: void fraction in single subchannel and rod bundle, multiple liquid temperatures at subchannel exit in rod bundle, and DNB power and location in rod bundle. All these results were obtained both in steady and transient conditions. Void fraction values are satisfactory predicted by CATHARE 3 in single subchannels with the pipe module. More dispersed predictions of void values are obtained in rod bundles with the CATHARE 3 3D module at subchannel scale. Single-phase liquid mixing tests and DNB tests in rod bundle are also analyzed. After calibrating the mixing in liquid single phase with specific tests, DNB tests using void mixing give mitigated results, perhaps linked to inappropriate use of CHF lookup tables in such rod bundles with many spacers.
Investigations on flow induced vibration of simulated CANDU fuel bundles in a pipe
International Nuclear Information System (INIS)
In this paper, vibration of a two-bundle string consisting of simulated CANDU fuel bundles subjected to turbulent liquid flow is investigated through numerical simulations and experiments. Large eddy simulation is used to solve the three-dimensional turbulent flow surrounding the fuel bundles for determining fluid excitations. The CFD model includes pipe flow, flow through the inlet fuel bundle along with its two endplates, half of the second bundle and its upstream endplate. The fluid excitation obtained from the fluid model is subsequently fed into a fuel bundle vibration code written in FORTRAN. Fluid structure interaction terms for the fuel elements are approximated using the slender body theory. Simulation results are compared to measurements conducted on the simulated fuel bundles in a testing hydraulic loop. (author)
Bagger-Witten line bundles on moduli spaces of elliptic curves
Gu, W
2016-01-01
In this paper we discuss Bagger-Witten line bundles over moduli spaces of SCFTs. We review how in general they are `fractional' line bundles, not honest line bundles, twisted on triple overlaps. We discuss the special case of moduli spaces of elliptic curves in detail. There, the Bagger-Witten line bundles does not exist as an ordinary line bundle, but rather is necessarily fractional. As a fractional line bundle, it is nontrivial (though torsion) over the uncompactified moduli stack, and its restriction to the interior, excising corners with enhanced stabilizers, is also fractional. We review and compare to results of recent work arguing that well-definedness of the worldsheet metric implies that the Bagger-Witten line bundle is torsion, and give general arguments on the existence of universal structures on moduli spaces of SCFTs, in which superconformal deformation parameters are promoted to nondynamical fields ranging over the SCFT moduli space.
Integral Canonical Models for Automorphic Vector Bundles of Abelian Type
Lovering, Tom
2016-01-01
We define and construct integral canonical models for automorphic vector bundles over Shimura varieties of abelian type. More precisely, we first build on Kisin's work to construct integral canonical models over rings of integers of number fields with finitely many primes inverted for Shimura varieties of abelian type with hyperspecial level at all primes we do not invert, compatible with Kisin's construction. We then define a notion of an integral canonical model for the standard principal b...
Lateral mechanical coupling of stereocilia in cochlear hair bundles.
Langer, M G; Fink, S.; Koitschev, A; Rexhausen, U; Hörber, J K; Ruppersberg, J P
2001-01-01
For understanding the gating process of transduction channels in the inner ear it is essential to characterize and examine the functional properties of the ultrastructure of stereociliary bundles. There is strong evidence that transduction channels in hair cells are gated by directly pulling at the so-called tip links. In addition to these tip links a second class of filamentous structures was identified in the scanning and transmission electron microscope: the side-to-side links. These links...
Universality Class of Fiber Bundle Model on Complex Networks
Kim, Dong-Hee; Kim, Beom Jun; Jeong, Hawoong
2004-01-01
We investigate the failure characteristics of complex networks within the framework of the fiber bundle model subject to the local load sharing rule in which the load of the broken fiber is transferred only to its neighbor fibers. Although the load sharing is strictly local, it is found that the critical behavior belongs to the universality class of the global load sharing where the load is transferred equally to all fibers in the system. From the numerical simulations and the analytical appr...
"Bundle Data" Approach at GES DISC Targeting Natural Hazards
Shie, C. L.; Shen, S.; Kempler, S. J.
2015-12-01
Severe natural phenomena such as hurricane, volcano, blizzard, flood and drought have the potential to cause immeasurable property damages, great socioeconomic impact, and tragic loss of human life. From searching to assessing the "Big", i.e., massive and heterogeneous scientific data (particularly, satellite and model products) in order to investigate those natural hazards, it has, however, become a daunting task for Earth scientists and applications researchers, especially during recent decades. The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has served "Big" Earth science data, and the pertinent valuable information and services to the aforementioned users of diverse communities for years. In order to help and guide our users to online readily (i.e., with a minimum effort) acquire their requested data from our enormous resource at GES DISC for studying their targeted hazard/event, we have thus initiated a "Bundle Data" approach in 2014, first targeting the hurricane event/topic. We have recently worked on new topics such as volcano and blizzard. The "bundle data" of a specific hazard/event is basically a sophisticated integrated data package consisting of a series of proper datasets containing a group of relevant ("knowledge-based") data variables readily accessible to users via a system-prearranged table linking those data variables to the proper datasets (URLs). This online approach has been developed by utilizing a few existing data services such as Mirador as search engine; Giovanni for visualization; and OPeNDAP for data access, etc. The online "Data Cookbook" site at GES DISC is the current host for the "bundle data". We are now also planning on developing an "Automated Virtual Collection Framework" that shall eventually accommodate the "bundle data", as well as further improve our management in "Big Data".
The Business of Bundling: Joining Forces on Joint Replacement.
Kaldy, Joanne
2016-03-01
A mandated bundled-payment program for joint replacement is in place in several regions across the country, and practitioners such as pharmacists are still sorting out their roles in this federal initiative. To get involved, pharmacists need to establish connections with area hospitals and physician groups to promote and document their ability to manage medications, reduce and eliminate medication-related problems and rehospitalizations, and work with patients to maximize adherence and improve communication for those undergoing hip and knee replacement.
Bundling telecommunications services : competitive strategies for converging markets.
Krämer, Jan
2009-01-01
With the advent of digital convergence, incumbent telephone and cable companies have begun to offer their services, such as voice telephony, Internet and TV in so-called triple play packages. While carefully recognizing the technological, legal and economic framework of the fixed-line telecommunications industry, this book investigates whether bundling is indeed a profitable pricing strategy for the firms and if it can possibly facilitate the leverage of market power into neighboring markets.
The effects of fee bundling on dental utilization.
Porter, J.; Coyte, P. C.; Barnsley, J.; Croxford, R.
1999-01-01
OBJECTIVE: To examine dental utilization following an adjustment to the provincial fee schedule in which preventive maintenance (recall) services were bundled at lower fees. DATA SOURCES/STUDY SETTING: Blue Cross dental insurance claims for claimants associated with four major Ontario employers using a common insurance plan over the period 1987-1990. STUDY DESIGN: This before-and-after design analyzes the dental claims experience over a four-year period for 4,455 individuals 18 years of age a...
Continuous damage fiber bundle model for strongly disordered materials
Raischel, F.; Kun Ferenc (1966-) (fizikus); Herrmann, Hans J.
2008-01-01
We present an extension of the continuous damage fiber bundle model to describe the gradual degradation of highly heterogeneous materials under an increasing external load. Breaking of a fiber in the model is preceded by a sequence of partial failure events occurring at random threshold values. In order to capture the subsequent propagation and arrest of cracks, furthermore, the disorder of the number of degradation steps of material constituents, the failure thresholds of single fibers are s...
Image processing for cameras with fiber bundle image relay.
Olivas, Stephen J; Arianpour, Ashkan; Stamenov, Igor; Morrison, Rick; Stack, Ron A; Johnson, Adam R; Agurok, Ilya P; Ford, Joseph E
2015-02-10
Some high-performance imaging systems generate a curved focal surface and so are incompatible with focal plane arrays fabricated by conventional silicon processing. One example is a monocentric lens, which forms a wide field-of-view high-resolution spherical image with a radius equal to the focal length. Optical fiber bundles have been used to couple between this focal surface and planar image sensors. However, such fiber-coupled imaging systems suffer from artifacts due to image sampling and incoherent light transfer by the fiber bundle as well as resampling by the focal plane, resulting in a fixed obscuration pattern. Here, we describe digital image processing techniques to improve image quality in a compact 126° field-of-view, 30 megapixel panoramic imager, where a 12 mm focal length F/1.35 lens made of concentric glass surfaces forms a spherical image surface, which is fiber-coupled to six discrete CMOS focal planes. We characterize the locally space-variant system impulse response at various stages: monocentric lens image formation onto the 2.5 μm pitch fiber bundle, image transfer by the fiber bundle, and sensing by a 1.75 μm pitch backside illuminated color focal plane. We demonstrate methods to mitigate moiré artifacts and local obscuration, correct for sphere to plane mapping distortion and vignetting, and stitch together the image data from discrete sensors into a single panorama. We compare processed images from the prototype to those taken with a 10× larger commercial camera with comparable field-of-view and light collection. PMID:25968031
The existence of a kind of bundle map
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
3 By means of the theory of Postnikov resolution, a sufficient condition for the existence of a kind of bundle maps is obtained. Some applications of the result are given. Particularly, it is proven that the deleted products as well as configuration spaces of two simply connected manifolds with suitable dimension have the same homotopy type when the original manifolds are homotopically equivalent.
Prostaglandins temporally regulate cytoplasmic actin bundle formation during Drosophila oogenesis
Spracklen, Andrew J.; Kelpsch, Daniel J.; Chen, Xiang; Spracklen, Cassandra N.; Tootle, Tina L.
2014-01-01
Prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin dynamics in cell culture and platelets, but their roles during development are largely unknown. Here we define a new role for Pxt, the Drosophila COX-like enzyme, in regulating the actin cytoskeleton—temporal restriction of actin remodeling during oogenesis. PGs are required for actin filament bundle formation during stage 10B (S10B). In addition, loss of Pxt results in extensive early actin ...
Topological Aharonov-Bohm Effect and Pseudo-Particle Bundles
Payandeh, Farrin
2016-10-01
Exploiting a topological approach, we discuss the outstanding Aharonov-Bohm effect and try to explain it in the context of the principal P(M, U(1)) bundle. We show that this could be done by excluding a specific region from the main manifold which acts as the solenoid around which the effect is observed. Moreover, we discuss the impacts of pseudo-particles in this topological approach.
Wrap groups of fiber bundles over quaternions and octonions
Ludkovsky, S. V.
2008-01-01
This article is devoted to the investigation of wrap groups of connected fiber bundles over the fields of real $\\bf R$, complex $\\bf C$ numbers, the quaternion skew field $\\bf H$ and the octonion algebra $\\bf O$. These groups are constructed with mild conditions on fibers. Their examples are given. It is shown, that these groups exist and for differentiable fibers have the infinite dimensional Lie groups structure, that is, they are continuous or differentiable manifolds and the composition $...
Heat transfer augmentation in rod bundles near grid spacers
International Nuclear Information System (INIS)
Heat transfer augmentation by straight grid spacers in rod bundles is studied for single phase flow and for post critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single phase flow is also examined. Governing heat transfer mechanisms are analyzed, and predictive formulations are established. For single phase flow, the local heat transfer at a straight spacer and at its upstream or downstream locations are treated separately. 18 refs
Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording
Shingo Tsukada; Hiroshi Nakashima; Keiichi Torimitsu
2012-01-01
Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in bot...
ETA INVARIANTS, DIFFERENTIAL CHARACTERS AND FLAT VECTOR BUNDLES
Institute of Scientific and Technical Information of China (English)
J.M.BISMUT
2005-01-01
The purpose of this paper is to give a refinement of the Atiyah-Singer families index theorem at the level of differential characters. Also a Riemann-Roch-Grothendieck theorem for the direct image of flat vector bundles by proper submersions is proved,with Chern classes with coefficients in C/Q. These results are much related to prior work of Gillet-Soule, Bismut-Lott and Lott.
Edinburgh Motor Assessment (EMAS)
Bak, Thomas
2013-01-01
Edinburgh Motor Assessment (EMAS) is a brief motor screening test, specifically designed for assessment of patients with dementia, aphasia and other cognitive disorders. It focuses, therefore, on those motor symptoms, which are known to occur in association with these diseases, such as extrapyramidal, amyotrophic, and cerebellar features as well as complex cognitive‐motor phenomena such as apraxia. EMAS has been developed by a team of neurologists and psychiatrists at the ...
Krakauer, John W.; Shadmehr, Reza
2005-01-01
A question of great recent interest is whether motor memory consolidates in a manner analogous to declarative memories, with the formation of a memory that progresses over time from a fragile state, susceptible to interference by a lesion or a conflicting motor task, to a stabilized state, resistant to such interference. Here, we first review studies that examine the anatomical basis for motor consolidation: evidence implicates cerebellar circuitry for two types of associative motor learning,...
Mass Transport Through Carbon Nanotube-Polystyrene Bundles
Lin, Rongzhou; Tran, Tuan
2016-05-01
Carbon nanotubes have been widely used as test channels to study nanofluidic transport, which has been found to have distinctive properties compared to transport of fluids in macroscopic channels. A long-standing challenge in the study of mass transport through carbon nanotubes (CNTs) is the determination of flow enhancement. Various experimental investigations have been conducted to measure the flow rate through CNTs, mainly based on either vertically aligned CNT membranes or individual CNTs. Here, we proposed an alternative approach that can be used to quantify the mass transport through CNTs. This is a simple method relying on the use of carbon nanotube-polystyrene bundles, which are made of CNTs pulled out from a vertically aligned CNT array and glued together by polystyrene. We experimentally showed by using fluorescent tagging that the composite bundles allowed measureable and selective mass transport through CNTs. This type of composite bundle may be useful in various CNT research areas as they are simple to fabricate, less likely to form macroscopic cracks, and offer a high density of CNT pores while maintaining the aligned morphology of CNTs.
Gaining Surgical Access for Repositioning the Inferior Alveolar Neurovascular Bundle
Directory of Open Access Journals (Sweden)
Saif Yousif Abdullah Al-Siweedi
2014-01-01
Full Text Available This study is aimed at determining anatomical landmarks that can be used to gain access to the inferior alveolar neurovascular (IAN bundle. Scanned CBCT (i-CAT machine data of sixty patients and reconstructions performed using the SimPlant dental implant software were reviewed. Outcome variables were the linear distances of the mandibular canal to the inferior border and the buccal cortex of the mandible, measured immediately at the mental foramen (D1 and at 10, 20, 30, and 40 mm (D2–D5 distal to it. Predictor variables were age, ethnicity, and gender of subjects. Apicobasal assessment of the canal reveals that it is curving downward towards the inferior mandibular border until 20 mm (D3 distal to the mental foramen where it then curves upwards, making an elliptic-arc curve. The mandibular canal also forms a buccolingually oriented elliptic arc in relation to the buccal cortex. Variations due to age, ethnicity, and gender were evident and this study provides an accurate anatomic zone for gaining surgical access to the IAN bundle. The findings indicate that the buccal cortex-IAN distance was greatest at D3. Therefore, sites between D2 and D5 can be used as favorable landmarks to access the IAN bundle with the least complications to the patient.
Conservation of helical bundle structure between the exocyst subunits.
Directory of Open Access Journals (Sweden)
Nicole J Croteau
Full Text Available BACKGROUND: The exocyst is a large hetero-octomeric protein complex required for regulating the targeting and fusion of secretory vesicles to the plasma membrane in eukaryotic cells. Although the sequence identity between the eight different exocyst subunits is less than 10%, structures of domains of four of the subunits revealed a similar helical bundle topology. Characterization of several of these subunits has been hindered by lack of soluble protein for biochemical and structural studies. METHODOLOGY/PRINCIPAL FINDINGS: Using advanced hidden Markov models combined with secondary structure predictions, we detect significant sequence similarity between each of the exocyst subunits, indicating that they all contain helical bundle structures. We corroborate these remote homology predictions by identifying and purifying a predicted domain of yeast Sec10p, a previously insoluble exocyst subunit. This domain is soluble and folded with approximately 60% alpha-helicity, in agreement with our predictions, and capable of interacting with several known Sec10p binding partners. CONCLUSIONS/SIGNIFICANCE: Although all eight of the exocyst subunits had been suggested to be composed of similar helical bundles, this has now been validated by our hidden Markov model structure predictions. In addition, these predictions identified protein domains within the exocyst subunits, resulting in creation and characterization of a soluble, folded domain of Sec10p.
Fabrication of CANFLEX bundle kit for irradiation test in NRU
Energy Technology Data Exchange (ETDEWEB)
Cho, Moon Sung; Kwon, Hyuk Il; Ji, Chul Goo; Chang, Ho Il; Sim, Ki Seob; Suk, Ho Chun
1997-10-01
CANFLEX bundle kit was prepared at KAERI for the fabrication of complete bundle at AECL. Completed bundle will be used for irradiation test in NRU. Provisions in the `Quality Assurance Manual for HWR Fuel Projects,` `Manufacturing Plan` and `Quality Verification, Inspection and Test Plan` were implemented as appropriately for the preparation of CANFLEX kit. A set of CANFLEX kit consist of 43 fuel sheath of two different sizes with spacers, bearing pads and buttons attached, 2 pieces of end plates and 86 pieces of end caps with two different sizes. All the documents utilized as references for the fabrication such as drawings, specifications, operating instructions, QC instructions and supplier`s certificates are specified in this report. Especially, suppliers` certificates and inspection reports for the purchased material as well as KAERI`s inspection report are integrated as attachments to this report. Attached to this report are supplier`s certificates and KAERI inspection reports for the procured materials and KAERI QC inspection reports for tubes, pads, spacers, buttons, end caps, end plates and fuel sheath. (author). 37 refs.
Enhanced boiling heat transfer in horizontal test bundles
Energy Technology Data Exchange (ETDEWEB)
Trewin, R.R.; Jensen, M.K.; Bergles, A.E.
1994-08-01
Two-phase flow boiling from bundles of horizontal tubes with smooth and enhanced surfaces has been investigated. Experiments were conducted in pure refrigerant R-113, pure R-11, and mixtures of R-11 and R-113 of approximately 25, 50, and 75% of R-113 by mass. Tests were conducted in two staggered tube bundles consisting of fifteen rows and five columns laid out in equilateral triangular arrays with pitch-to-diameter ratios of 1.17 and 1.5. The enhanced surfaces tested included a knurled surface (Wolverine`s Turbo-B) and a porous surface (Linde`s High Flux). Pool boiling tests were conducted for each surface so that reference values of the heat transfer coefficient could be obtained. Boiling heat transfer experiments in the tube bundles were conducted at pressures of 2 and 6 bar, heat flux values from 5 to 80 kW/m{sup 2}s, and qualities from 0% to 80%, Values of the heat transfer coefficients for the enhanced surfaces were significantly larger than for the smooth tubes and were comparable to the values obtained in pool boiling. It was found that the performance of the enhanced tubes could be predicted using the pool boiling results. The degradation in the smooth tube heat transfer coefficients obtained in fluid mixtures was found to depend on the difference between the molar concentration in the liquid and vapor.
Real bundle gerbes, orientifolds and twisted KR-homology
Hekmati, Pedram; Szabo, Richard J; Vozzo, Raymond F
2016-01-01
We introduce a notion of Real bundle gerbes on manifolds equipped with an involution. We elucidate their relation to Jandl gerbes and prove that they are classified by their Real Dixmier-Douady class in Grothendieck's equivariant sheaf cohomology. We show that the Grothendieck group of Real bundle gerbe modules is isomorphic to twisted KR-theory for a torsion Real Dixmier-Douady class. Building on the Baum-Douglas model for K-homology and the orientifold construction in string theory, we introduce geometric cycles for twisted KR-homology groups using Real bundle gerbe modules. We prove that this defines a real-oriented generalised homology theory dual to twisted KR-theory for Real closed manifolds, and more generally for Real finite CW-complexes, for any Real Dixmier-Douady class. This is achieved by defining an explicit natural transformation to analytic twisted KR-homology and proving that it is an isomorphism. Our constructions give a new framework for the classification of orientifolds in string theory, p...
Explicit presentations of nonspecial line bundles and secant spaces
Kim, Seonja
2012-01-01
A line bundle L on a smooth curve X is nonspecial if and only if L admits a presentation L=K_X -D +E for some effective divisors D and E>0 on X with gcd (D, E)=0 and h^0 (X, O_X (D))=1. In this work, we define a minimal presentation of L which is minimal with respect to the degree of E among the presentations. If L=K_X -D +E with degE>2 is a minimal, then L is very ample and any q-points of X with q
Institute of Scientific and Technical Information of China (English)
LUO Hao; AO Ying-fang; ZHANG Wei-guang; LIU Sheng-yong; ZHANG Ji-ying; YU Jia-kuo
2012-01-01
Background Several techniques have been described for posterior cruciate ligament(PCL)reconstruction.However,double-bundle PCL reconstruction using the quadruple bone-tunnel technique has been seldom reported.The current study investigated this technique,focusing on the anatomy of the femoral and tibial insertions of the anterolateral(AL)and posteromedial(PM)bundles of the PCL.Methods Twenty-two fresh,healthy adult cadaveric knees were dissected and measured.The PCL was divided into the AL bundle and PM bundle at the insertion footprint.The insertion footprints of the AL and PM bundles,their location,size,and the clock positions were measured and described.Results On the femur,the clock position of the footprint of the AL bundle was 11:21±0:23(left)or 0:39±0:23(right),and the PM bundle was 9:50±0:18(left)or 2:10±0:18(right),with the knee flexed at 90 degrees.The distances from the center of the femoral insertions of the AL and PM bundles to the anterior cartilage margins of the medial femoral condyle were(7.79±1.22)mm and(8.36±1.63)mm,respectively.On the tibia,the vertical distances from the center of the tibial insertions of the AL and PM bundles to the tibial articular surface were(3.25±1.20)mm and(6.91±1.57)mm,respectively.Conclusions These results have led to a better definition of the anatomy of the AL and PM bundle footprint of the PCL.The technique of double-bundle PCL reconstruction using quadruple bone-tunnel is feasible.Application of these data during PCL reconstruction using the quadruple bone-tunnel technique may help optimize knee stability.
Goulding, Martyn
2012-01-01
Animals use a form of sensory feedback termed proprioception to monitor their body position and modify the motor programs that control movement. In this issue of Neuron, Wen et al. (2012) provide evidence that a subset of motor neurons function as proprioceptors in C. elegans, where B-type motor neurons sense body curvature to control the bending movements that drive forward locomotion.
Fateev, Evgeny G
2013-01-01
In a popular language, the possibilities of the Casimir expulsion effect are presented, which can be the basis of quantum motors. Such motors can be in the form of a special multilayer thin film with periodic and complex nanosized structures. Quantum motors of the type of the Casimir platforms can be the base of transportation, energy and many other systems in the future.
HLM fuel pin bundle experiments in the CIRCE pool facility
Energy Technology Data Exchange (ETDEWEB)
Martelli, Daniele, E-mail: daniele.martelli@ing.unipi.it [University of Pisa, Department of Civil and Industrial Engineering, Pisa (Italy); Forgione, Nicola [University of Pisa, Department of Civil and Industrial Engineering, Pisa (Italy); Di Piazza, Ivan; Tarantino, Mariano [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone (Italy)
2015-10-15
Highlights: • The experimental results represent the first set of values for LBE pool facility. • Heat transfer is investigated for a 37-pin electrical bundle cooled by LBE. • Experimental data are presented together with a detailed error analysis. • Nu is computed as a function of the Pe and compared with correlations. • Experimental Nu is about 25% lower than Nu derived from correlations. - Abstract: Since Lead-cooled Fast Reactors (LFR) have been conceptualized in the frame of GEN IV International Forum (GIF), great interest has focused on the development and testing of new technologies related to HLM nuclear reactors. In this frame the Integral Circulation Experiment (ICE) test section has been installed into the CIRCE pool facility and suitable experiments have been carried out aiming to fully investigate the heat transfer phenomena in grid spaced fuel pin bundles providing experimental data in support of European fast reactor development. In particular, the fuel pin bundle simulator (FPS) cooled by lead bismuth eutectic (LBE), has been conceived with a thermal power of about 1 MW and a uniform linear power up to 25 kW/m, relevant values for a LFR. It consists of 37 fuel pins (electrically simulated) placed on a hexagonal lattice with a pitch to diameter ratio of 1.8. The FPS was deeply instrumented by several thermocouples. In particular, two sections of the FPS were instrumented in order to evaluate the heat transfer coefficient along the bundle as well as the cladding temperature in different ranks of sub-channels. Nusselt number in the central sub-channel was therefore calculated as a function of the Peclet number and the obtained results were compared to Nusselt numbers obtained from convective heat transfer correlations available in literature on Heavy Liquid Metals (HLM). Results reported in the present work, represent the first set of experimental data concerning fuel pin bundle behaviour in a heavy liquid metal pool, both in forced and
Lateral mechanical coupling of stereocilia in cochlear hair bundles.
Langer, M G; Fink, S; Koitschev, A; Rexhausen, U; Hörber, J K; Ruppersberg, J P
2001-06-01
For understanding the gating process of transduction channels in the inner ear it is essential to characterize and examine the functional properties of the ultrastructure of stereociliary bundles. There is strong evidence that transduction channels in hair cells are gated by directly pulling at the so-called tip links. In addition to these tip links a second class of filamentous structures was identified in the scanning and transmission electron microscope: the side-to-side links. These links laterally connect stereocilia of the same row of a hair bundle. This study concentrates on mechanical coupling of stereocilia of the tallest row connected by side-to-side links. Atomic Force microscopy (AFM) was used to investigate hair bundles of outer hair cells (OHCs) from postnatal rats (day 4). Although hair bundles of postnatal rats are still immature at day 4 and interconnecting cross-links do not show preferential direction yet, hair bundles of investigated OHCs already showed the characteristic V-shape of mature hair cells. In a first experiment, the stiffness of stereocilia was investigated scanning individual stereocilia with an AFM tip. The spring constant for the excitatory direction was 2.5 +/- 0.6 x 10(-3) N/m whereas a higher spring constant (3.1 +/- 1.5 x 10(-3) N/m) was observed in the inhibitory direction. In a second set of experiments, the force transmission between stereocilia of the tallest row was measured using AFM in combination with a thin glass fiber. This fiber locally displaced a stereocilium while the force laterally transmitted to the neighboring untouched taller stereocilia was measured by AFM. The results show a weak force interaction between tallest stereocilia of postnatal rats. The force exerted to an individual stereocilium declines to 36% at the nearest adjacent stereocilium of the same row not touched with the fiber. It is suggested that the amount of force transmitted from a taller stereocilium to an adjacent one of the same row depends
Compactifications of the Heterotic string with unitary bundles
Energy Technology Data Exchange (ETDEWEB)
Weigand, T.
2006-05-23
In this thesis we investigate a large new class of four-dimensional supersymmetric string vacua defined as compactifications of the E{sub 8} x E{sub 8} and the SO(32) heterotic string on smooth Calabi-Yau threefolds with unitary gauge bundles and heterotic five-branes. The first part of the thesis discusses the implementation of this idea into the E{sub 8} x E{sub 8} heterotic string. After specifying a large class of group theoretic embeddings featuring unitary bundles, we analyse the effective four-dimensional N=1 supergravity upon compactification. From the gauge invariant Kaehler potential for the moduli fields we derive a modification of the Fayet-Iliopoulos D-terms arising at one-loop in string perturbation theory. From this we conjecture a one-loop deformation of the Hermitian Yang-Mills equation and introduce the idea of {lambda}-stability as the perturbatively correct stability concept generalising the notion of Mumford stability valid at tree-level. We then proceed to a definition of SO(32) heterotic vacua with unitary gauge bundles in the presence of heterotic five-branes and find agreement of the resulting spectrum with the S-dual framework of Type I/Type IIB orientifolds. A similar analysis of the effective four-dimensional supergravity is performed. Further evidence for the proposed one-loop correction to the stability condition is found by identifying the heterotic corrections as the S-dual of the perturbative part of {pi}-stability as the correct stability concept in Type IIB theory. After reviewing the construction of holomorphic stable vector bundles on elliptically fibered Calabi-Yau manifolds via spectral covers, we provide semi-realistic examples for SO(32) heterotic vacua with Pati-Salam and MSSM-like gauge sectors. We finally discuss the construction of realistic vacua with flipped SU(5) GUT and MSSM gauge group within the E{sub 8} x E{sub 8} framework, based on the embedding of line bundles into both E{sub 8} factors. Some of the appealing
Sadoghi, Patrick; Mueller, Peter E.; Jansson, Volkmar; van Griensven, Martin; Kroepfl, Albert; Fischmeister, Martin F.
2011-01-01
The study hypothesis was that the outcome of semitendinosus gracilis double bundle (STG-DB) anterior cruciate ligament (ACL) reconstruction is advantageous in terms of clinical results and restoration of anterior-posterior and rotational laxity in comparison to bone-patellar tendon-bone single-bundl
Shafer, J. I.; Marsh, H. E., Jr. (Inventor)
1978-01-01
A case bonded end burning solid propellant rocket motor is described. A propellant with sufficiently low modulus to avoid chamber buckling on cooling from cure and sufficiently high elongation to sustain the stresses induced without cracking is used. The propellant is zone cured within the motor case at high pressures equal to or approaching the pressure at which the motor will operate during combustion. A solid propellant motor with a burning time long enough that its spacecraft would be limited to a maximum acceleration of less than 1 g is provided by one version of the case bonded end burning solid propellant motor of the invention.
Hickam, Christopher Dale
2008-05-13
A motor/generator is provided for connecting between a transmission input shaft and an output shaft of a prime mover. The motor/generator may include a motor/generator housing, a stator mounted to the motor/generator housing, a rotor mounted at least partially within the motor/generator housing and rotatable about a rotor rotation axis, and a transmission-shaft coupler drivingly coupled to the rotor. The transmission-shaft coupler may include a clamp, which may include a base attached to the rotor and a plurality of adjustable jaws.
Induction motor control design
Marino, Riccardo; Verrelli, Cristiano M
2010-01-01
""Nonlinear and Adaptive Control Design for Induction Motors"" is a unified exposition of the most important steps and concerns in the design of estimation and control algorithms for induction motors. A single notation and modern nonlinear control terminology is used to make the book accessible to readers who are not experts in electric motors at the same time as giving a more theoretical control viewpoint to those who are. In order to increase readability, the book concentrates on the induction motor, eschewing the much more complex and less-well-understood control of asynchronous motors. The
Motor degradation prediction methods
Energy Technology Data Exchange (ETDEWEB)
Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.
1996-12-01
Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.
Piezoelectric Motors, an Overview
Directory of Open Access Journals (Sweden)
Karl Spanner
2016-02-01
Full Text Available Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ultrasonic motors, inertia-drive, and piezo-walk-drive. In this review, a comprehensive summary of piezoelectric motors, with their classification from initial idea to recent progress, is presented. This review also includes some of the industrial and commercial applications of piezoelectric motors that are presently available in the market as actuators.
Neuroplasticity & Motor Learning
DEFF Research Database (Denmark)
Jensen, Jesper Lundbye
is a measure of our ability to form and store a motor memory of the task. However, the initial memory of the task is labile and may be subject to interference. During and following motor learning plastic changes occur within the central nervous system. On one hand these changes are driven by motor practice......, on the other hand the changes underlie the formation of motor memory and the retention of improved motor performance. During motor learning changes may occur at many different levels within the central nervous system dependent on the type of task and training. Here, we demonstrate different studies from our......Practice of a new motor task is usually associated with an improvement in performance. Indeed, if we stop practicing and return the next day to the same task, we find that our performance has been maintained and may even be better than it was at the start of the first day. This improvement...
Double-bundle depiction of the anterior cruciate ligament at 3 Tesla
Energy Technology Data Exchange (ETDEWEB)
Adriaensen, M.E.A.P.M. [Atrium Medical Center Parkstad, Department of Radiology, Heerlen (Netherlands); Hogan, B. [Sports Surgery Clinic, Department of Radiology, Dublin (Ireland); Al-Bulushi, H.I.J. [Armed Forces Hospital, Department of Radiology, Muscat (Oman); Kavanagh, E.C. [Mater Misericordiae Hospital, Department of Radiology, Dublin (Ireland)
2012-07-15
Magnetic resonance imaging on 3 Tesla (3T MRI) with arthroscopic correlation has proven to adequately identify the anteromedial bundle (AMB) and posterolateral bundle (PLB) in cadaver knees. The purpose of this study was to describe the depiction of ACL bundle anatomy on 3T MRI in daily practice. In a retrospective cohort study, we included 50 consecutive patients who underwent standard 3T MRI of the knee and had an intact ACL. Two musculoskeletal radiologists independently reviewed all scans for depiction of ACL bundle anatomy using standardized forms. Descriptive statistics were used. Twenty-three right knees (46%) and 27 left knees (54%) were included in the study. Mean age of the patients was 35 years (range 12 to 68 years); 37 patients were male (74%). ACL bundle anatomy was best depicted in the axial plane in 44 knees (88%) and in the coronal plane in six knees (12%). Two bundles were seen in 47 knees (94%). The AMB was completely seen in 45 knees (90%). The PLB was completely seen in 40 knees (80%). Both bundles were completely seen in 37 knees (76%). The double-bundle anatomy of the ACL is visualized in 94% of patients on 3T MRI. Because of potentially associated clinical benefits, we advocate to report separately on the anteromedial bundle and posterolateral bundle in case of anterior cruciate ligament injury of the knee. (orig.)
Local Pixel Bundles: Bringing the Pixels to the People
Anderson, Jay
2014-12-01
The automated galaxy-based alignment software package developed for the Frontier Fields program (hst2galign, see Anderson & Ogaz 2014 and http://www.stsci.edu/hst/campaigns/frontier-fields/) produces a direct mapping from the pixels of the flt frame of each science exposure into a common master frame. We can use these mappings to extract the flt-pixels in the vicinity of a source of interest and package them into a convenient "bundle". In addition to the pixels, this data bundle can also contain "meta" information that will allow users to transform positions from the flt pixels to the reference frame and vice-versa. Since the un-resampled pixels in the flt frames are the only true constraints we have on the astronomical scene, the ability to inter-relate these pixels will enable many high-precision studies, such as: point-source-fitting and deconvolution with accurate PSFs, easy exploration of different image-combining algorithms, and accurate faint-source finding and photometry. The data products introduced in this ISR are a very early attempt to provide the flt-level pixel constraints in a package that is accessible to more than the handful of experts in HST astrometry. The hope is that users in the community might begin using them and will provide feedback as to what information they might want to see in the bundles and what general analysis packages they might find useful. For that reason, this document is somewhat informally written, since I know that it will be modified and updated as the products and tools are optimized.
Hydrodynamic behavior of a bare rod bundle. [LMFBR
Energy Technology Data Exchange (ETDEWEB)
Bartzis, J.G.; Todreas, N.E.
1977-06-01
The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers.
Noise alters hair-bundle mechanics at the cochlear apex
Strimbu, C. Elliott; Fridberger, Anders
2015-12-01
Exposure to loud sounds can lead to both permanent and short term changes in auditory sensitivity. Permanent hearing loss is often associated with gross changes in cochlear morphology including the loss of hair cells and auditory nerve fibers while the mechanisms of short term threshold shifts are much less well understood and may vary at different locations across the cochlea. Previous reports suggest that exposure to loud sounds leads to a decrease in the cochlear microphonic potential and in the stiffness of the organ of Corti. Because the cochlear microphonic reflects changes in the membrane potential of the hair cells, this suggests that hair-bundle motion should be reversibly altered following exposure to loud sounds. Using an in vitro preparation of the guinea pig temporal bone we investigate changes in the micro-mechanical response near the cochlear apex following a brief (up to 10 - 20 minutes) exposure to loud (˜ 120 dB) tones near the best frequency at this location. We use time-resolved confocal imaging to record the motion of outer hair cell bundles before and after acoustic overstimulation. We have also recorded larger-scale structural views of the organ of Corti before and after exposure to the loud sound. Conventional electrophysiological techniques are used measure the cochlear microphonic potential. As has been previously reported, following acoustic overexposure the cochlear microphonic declines in value and typically recovers on the order of 30 - 60 minutes. Hair-bundle trajectories are affected following the loud sound and typically recover on a somewhat faster time scale than the microphonic potential, although the results vary considerably across preparations. Preliminary results also suggest reversible changes in the hair cell's resting potential following the loud sound.
Semistable vector bundles and Tannaka duality from a computational point of view
Kaid, Almar
2011-01-01
We develop a semistability algorithm for vector bundles which are given as a kernel of a surjective morphism between splitting bundles on the projective space over an algebraically closed field K. This class of bundles is a generalization of syzygy bundles. We show how to implement this algorithm in a computer algebra system. Further we give applications, mainly concerning the computation of Tannaka dual groups of stable vector bundles of degree 0 on the projective space and on certain smooth complete intersection curves. We also use our algorithm to close a gap in a recent work of L. Costa, P. Macias Marques and R. M. Miro-Roig regarding the stability of the syzygy bundle of general forms. Finally, we apply our algorithm to provide a computational approach to tight closure. All algorithms are implemented in the computer algebra system CoCoA
FLP: a field line plotting code for bundle divertor design
International Nuclear Information System (INIS)
A computer code was developed to aid in the design of bundle divertors. The code can handle discrete toroidal field coils and various divertor coil configurations. All coils must be composed of straight line segments. The code runs on the PDP-10 and displays plots of the configuration, field lines, and field ripple. It automatically chooses the coil currents to connect the separatrix produced by the divertor to the outer edge of the plasma and calculates the required coil cross sections. Several divertor designs are illustrated to show how the code works
Bundle adjustment for data processing of theodolite industrial surveying system
Institute of Scientific and Technical Information of China (English)
邹峥嵘; 丁晓利; 曾卓乔; 何凭宗
2001-01-01
The photogrammetric bundle adjustment was used in data processing of electronic theodolite industrial surveying system by converting angular observations into virtual photo coordinates. The developed algorithm has ability of precision estimation and data-snooping, do not need initial values of exterior orientation elements and object point coordinates. The form of control condition for the system is quite flexible. Neither centering nor leveling is the theodolite needed and the lay-out of theodolite position is flexible when the system is used for precise survey. Experiments carried out in test field verify the validity of the data processing method.
Foliation, jet bundle and quantization of Einstein gravity
Park, I Y
2015-01-01
With the Hamiltonian and Lagrangian analyses in the ADM setup, it was observed in \\cite{Park:2014tia} that the physical configuration space of the 4D Einstein-Hilbert action admits a three-dimensional description. Subsequently, a more mathematical picture of the reduction based on foliation theory was presented in \\cite{Park:2014qoa}. In this work, we expand \\cite{Park:2014qoa} by adding another mathematical ingredient - an element of jet bundle theory - and present a more systematic and refined account thereof.
Visualization of the medial forebrain bundle using diffusion tensor imaging
Directory of Open Access Journals (Sweden)
Ardian eHana
2015-10-01
Full Text Available Diffusion tensor imaging is a technique that enables physicians the portrayal of white matter tracts in vivo. We used this technique in order to depict the medial forebrain bundle in 15 consecutive patients between 2012 and 2015. Men and women of all ages were included. There were 6 women and 9 men. The mean age was 58,6 years (39-77. Nine patients were candidates for an eventual deep brain stimulation. Eight of them suffered from Parkinson`s disease and one had multiple sclerosis. The remaining 6 patients suffered from different lesions which were situated in the frontal lobe. These were 2 metastasis, 2 meningiomas, 1 cerebral bleeding and 1 glioblastoma. We used a 3DT1-sequence for the navigation. Furthermore T2- and DTI- sequences were performed. The FOV was 200 x 200 mm², slice thickness 2 mm, and an acquisition matrix of 96 x 96 yielding nearly isotropic voxels of 2 x 2 x 2 mm. 3-Tesla-MRI was carried out strictly axial using 32 gradient directions and one b0-image. We used Echo-Planar-Imaging (EPI and ASSET parallel imaging with an acceleration factor of 2. b-value was 800 s/mm². The maximal angle was 50°. Additional scanning time was less than 9 minutes. We were able to visualize the medial forebrain bundle in 12 of our patients bilaterally and in the remaining 3 patients we depicted the medial forebrain bundle on one side. It was the contralateral side of the lesion. These were 2 meningiomas and one metastasis. Portrayal of the medial forebrain bundle is possible for everyday routine for neurosurgical interventions. As part of the reward circuitry it might be of substantial importance for neurosurgeons during deep brain stimulation in patients with psychiatric disorders. Furthermore it might explain at a certain extent character changes in patients with lesions in the frontal lobe. Surgery in this part of the brain should always take the preservation of this white matter tract into account.
Gauge Theories and Fiber Bundles: Definitions, Pictures, and Results
Marsh, Adam
2016-01-01
A pedagogical but concise overview of fiber bundles and their connections is provided, in the context of gauge theories in physics. The emphasis is on defining and visualizing concepts and relationships between them, as well as listing common confusions, alternative notations and jargon, and relevant facts and theorems. Special attention is given to detailed figures and geometric viewpoints, some of which would seem to be novel to the literature. Topics are avoided which are well covered in textbooks, such as historical motivations, proofs and derivations, and tools for practical calculations. The present paper is best read in conjunction with the similar paper on Riemannian geometry cited herein.
Isolated Left Bundle Branch Block in a Toddler
Directory of Open Access Journals (Sweden)
Hitesh Agrawal
2014-01-01
Full Text Available Left bundle branch block (LBBB usually occurs as a postoperative complication from surgical correction of congenital heart disease and can be associated with hypertensive heart disease, coronary artery disease, myocarditis, and aortic valvular disease. Although isolated LBBB is a conduction abnormality found in some healthy adults, it has not been reported in pediatric population. We report a 2-year-old, healthy African American female who was incidentally discovered to have isolated LBBB that has persisted in a follow-up of 3 years.
Principal Bundles whose Restrictions to a Curve are Isomorphic
Indian Academy of Sciences (India)
Sudarshan Rajendra Gurjar
2011-05-01
Let be a normal projective variety defined over an algebraically closed field . Let $|O_X(1)|$ be a very ample invertible sheaf on . Let be an affine algebraic group defined over . Let $E_G$ and $F_G$ be two principal -bundles on . Then there exists an integer $n \\gg 0$ (depending on $E_G$ and $F_G$) such that if the restrictions of $E_G$ and $F_G$ to a curve $C\\in |O_X(n)|$ are isomorphic, then they are isomorphic on all of .
Left bundle branch block: a rare ECG manifestation of hyperkalemia
Directory of Open Access Journals (Sweden)
Venkata Madhav M
2015-04-01
Full Text Available A 20-year-old female patient with chronic kidney disease was brought to our emergency medical department with symptoms of pain in chest and abdomen, vomitings. Laboratory testing revealed serum potassium 7.7 mEq/L, serum creatinine 9.1 mg/dL. Electrocardiogram (ECG showed left bundle branch block (LBBB pattern with left axis deviation, tall T waves and ST elevation. Among ECG alterations in hyperkalemia, LBBB is rare and is being reported in our case.
Quantum Bundle Description of the Quantum Projective Spaces
Buachalla, Réamonn Ó
2011-01-01
We realise Heckenberger and Kolb's canonical calculus on quantum projective (n-1)-space as the restriction of a distinguished quotient of the standard bicovariant calculus for Cq[SUn]. We introduce a calculus on the quantum (2n-1)-sphere in the same way. With respect to these choices of calculi, we present quantum projective (N-1)-space as the base space of two different quantum principal bundles, one with total space Cq[SUn], and the other with total space Cq[S^(2n-1)]. We go on to give Cq[C...
Parameter design and optimization of tight-lattice rod bundles
International Nuclear Information System (INIS)
Thin rod bundles with tight lattice are arranged according to the equilateral triangle grid, as the proportion of fuel is large, and the power density of core is high. Based on the analysis of the performance of core, the ABV-6M reactor is taken as the example, and two objective functions, power density and flow rate of coolant are proposed for optimization calculation. Diameter and pitch of rod are optimized by using GA method respectively. The results, which are considered to be safety in security checking, show that tight lattice is effective for improving the power density and other performances of the reactor core. (author)
On bundles of rank 3 computing Clifford indices
Lange, H
2012-01-01
Let $C$ be a smooth irreducible projective algebraic curve defined over the complex numbers. The notion of the Clifford index of $C$ was extended a few years ago to semistable bundles of any rank. Recent work has been focussed mainly on the rank-2 Clifford index, although interesting results have also been obtained for the case of rank 3. In this paper we extend this work, obtaining improved lower bounds for the rank-3 Clifford index. This allows the first computations of the rank-3 index in non-trivial cases and examples for which the rank-3 index is greater than the rank-2 index.
A Universal Family of Deformations for the Uniformising Higgs bundle
Dalakov, Peter
2011-01-01
Fix a simple complex Lie group G and a principal sl(2,C) subalgebra of Lie(G). Then the moduli space of semi-stable, topologically trivial G-Higgs bundles on a hyperbolic, spin Riemann surface acquires a marked point. This is the unique C*-fixed point on the Hitchin section. We describe a universal analytic family of deformations which provides holomorphic Darboux coordinates in a neighbourhood of the section. This is a special case of a more general deformation-theoretic construction in the spirit of Kuranishi theory. As a toy example of the latter we consider the tautological family of centralisers over the Kostant slice.
Natural Diagonal Riemannian Almost Product and Para-Hermitian Cotangent Bundles
Druta-Romaniuc, Simona-Luiza
2011-01-01
We obtain the natural diagonal almost product and locally product structures on the total space of the cotangent bundle of a Riemannian manifold. We find the Riemannian almost product (locally product) and the (almost) para-Hermitian cotangent bundles of natural diagonal lift type. We prove the characterization theorem for the natural diagonal (almost) para-K\\"ahlerian structures on the total spaces of the cotangent bundle.
Stavrou, Eleni T.; Brewster, Chris
2005-01-01
Strategic human resource management has been linked to competitive advantage and in turn to organizational performance. This linkage has been viewed from a universal, a contextual or a configurational perspective. Adopting the latter perspective, the authors of the present study investigate the possible Strategic HRM Bundles of competitive advantage within the EU and the extent to which these bundles are linked to business performance. The exploration revealed fifteen bundles: six of which ha...
Motor degradation prediction methods
International Nuclear Information System (INIS)
Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor's duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures
Bonanomi, Dario; Pfaff, Samuel L
2010-01-01
Motor neurons are functionally related, but represent a diverse collection of cells that show strict preferences for specific axon pathways during embryonic development. In this article, we describe the ligands and receptors that guide motor axons as they extend toward their peripheral muscle targets. Motor neurons share similar guidance molecules with many other neuronal types, thus one challenge in the field of axon guidance has been to understand how the vast complexity of brain connection...
Post-irradiation examination of the 37M fuel bundle at Chalk River Laboratories (AECL)
Energy Technology Data Exchange (ETDEWEB)
Armstrong, J. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Daniels, T. [Ontario Power Generation, Pickering, Ontario (Canada); Montin, J. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)
2014-03-15
The modified (-element (37M) fuel bundle was designed by Ontario Power Generation (OPG) to improve Critical Heat Flux (CHF) performance in ageing pressure tubes. A modification of the conventional 37-element fuel bundle design, the 37M fuel bundle allows more coolant flow through the interior sub-channels by way of a smaller central element. A demonstration irradiation (DI) of thirty-two fuel bundles was completed in 2011 at OPG's Darlington Nuclear Generating Station to confirm the suitability of the 37M fuel bundles for full core implementation. In support of the DI, fuel elements were examined in the Chalk River Laboratories Hot Cells. Inspection activities included: Bundle and element visual examination; Bundle and element dimensional measurements; Verification of bundle and element integrity; and Internal Gas Volume Measurements. The inspection results for 37M were comparable to that of conventional 37-element CANDU fuel. Fuel performance parameters of the 37M DI fuel bundle and fuel elements were within the range observed for similarly operated conventional 37-element CANDU fuel. Based on these Post Irradiation Examination (PIE) results, 37M fuel performed satisfactorily. (author)
Padilla-Gamiño, J. L.; Weatherby, T. M.; Waller, R. G.; Gates, R. D.
2011-06-01
The majority of scleractinian corals are hermaphrodites that broadcast spawn their gametes separately or packaged as egg-sperm bundles during spawning events that are timed to the lunar cycle. The egg-sperm bundle is an efficient way of transporting gametes to the ocean surface where fertilization takes place, while minimizing sperm dilution and maximizing the opportunity for gamete encounters during a spawning event. To date, there are few studies that focus on the formation and structure of egg-sperm bundle. This study explores formation, ultrastructure, and longevity of the egg-sperm bundle in Montipora capitata, a major reef building coral in Hawai`i. Our results show that the egg-sperm bundle is formed by a mucus layer secreted by the oocytes. The sperm package is located at the center of each bundle, possibly reflecting the development of male and female gametes in different mesenteries. Once the egg-sperm bundle has reached the ocean surface, it breaks open within 10-35 min, depending on the environmental conditions (i.e., wind, water turbulence). Although the bundle has an ephemeral life span, the formation of an egg-sperm bundle is a fundamental part of the reproductive process that could be strongly influenced by climate change and deterioration of water quality (due to anthropogenic effects) and thus requires further investigation.
Overview of methods to increase dryout power in CANDU fuel bundles
Energy Technology Data Exchange (ETDEWEB)
Groeneveld, D.C., E-mail: degroeneveld@gmail.com [Chalk River Laboratories, AECL, Chalk River (Canada); University of Ottawa, Department of Mechanical Engineering, Ottawa (Canada); Leung, L.K.H. [Chalk River Laboratories, AECL, Chalk River (Canada); Park, J.H. [Korean Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-06-15
Highlights: • Small changes in bundle geometry can have noticeable effects on the bundle CHF. • Rod spacing devices can results in increases of over 200% in CHF. • CHF enhancement decays exponentially downstream from spacers. • CHF-enhancing bundle appendages also increase the post-CHF heat transfer. - Abstract: In CANDU reactors some degradation in the CCP (critical channel power, or power corresponding to the first occurrence of CHF in any fuel channel) will occur with time because of ageing effects such as pressure-tube diametral creep, increase in reactor inlet-header temperature, increased hydraulic resistance of feeders. To compensate for the ageing effects, various options for recovering the loss in CCP are described in this paper. They include: (i) increasing the bundle heated perimeter, (ii) optimizing the bundle configuration, (iii) optimizing core flow and flux distribution, (iv) reducing the bundle hydraulic resistance, (v) use of CHF-enhancing bundle appendages, (vi) more precise experimentation, and (vii) redefining CHF. The increase in CHF power has been quantified based on experiments on full-scale bundles and subchannel code predictions. The application of several of these CHF enhancement principles has been used in the development of the 43-rod CANFLEX bundle.
Numerical model for thermal and mechanical behaviour of a CANDU 37-element bundle
International Nuclear Information System (INIS)
Prediction of transient fuel bundle deformations is important for assessing the integrity of fuel and the surrounding structural components under different operating conditions including accidents. For numerical simulation of the interactions between fuel bundle and pressure tube, a reliable numerical bundle model is required to predict thermal and mechanical behaviour of the fuel bundle assembly under different thermal loading conditions. To ensure realistic representations of the bundle behaviour, this model must include all of the important thermal and mechanical features of the fuel bundle, such as temperature-dependent material properties, thermal viscoplastic deformation in sheath, fuel-to-sheath interactions, endplate constraints and contacts between fuel elements. In this paper, we present a finite element based numerical model for predicting macroscopic transient thermal-mechanical behaviour of a complete 37-element CANDU nuclear fuel bundle under accident conditions and demonstrate its potential for being used to investigate fuel bundle to pressure tube interaction in future nuclear safety analyses. This bundle model has been validated against available experimental and numerical solutions and applied to various simulations involving steady-state and transient loading conditions. (author)
Redesign and replacement of Connecticut Yankee moisture separator/reheater (MSR) tube bundles
International Nuclear Information System (INIS)
This paper describes the various aspects of the tube bundle redesign and replacement coordinated by Northeast Utilities Service Company for the Connecticut Yankee Atomic Power Company during the plant's 1980 refueling outage. The main objective of the replacement was to improve the operating reliability along with secondary plant chemistry through the use of new bundle design and tube material. The considerations leading to the selection of material and design of the new bundles, the highlights of fabrication and bundle change-out, and the eddy current test experience and performance monitoring techniques and results are presented. 6 refs
Significance of the resting angles of hair-cell bundles for Hopf bifurcation criticality
Kim, Kyung-Joong; Ahn, Kang-Hun
2016-08-01
We investigate the significance of the inclined angle of a hair bundle at equilibrium. We find that, while the angle gives a geometrical conversion factor between the bundle deflection and the ion channel displacement, it also controls the dynamics of the bundle. We show that a Hopf bifurcation, which enhances sensitivity, can be driven by the geometrical factor. However, existing experimental data indicate that mammalian auditory hair-cell bundles are located far away from the Hopf bifurcation point, suggesting that the high sensitivity of mammalian hearing might come from other mechanisms.
Cryogenic Electric Motor Tested
Brown, Gerald V.
2004-01-01
Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.
Control motor brushless sensorless
Solchaga Pérez de Lazárraga, Gonzalo
2015-01-01
El proyecto consiste en la creación de un circuito capaz de controlar la velocidad de un motor brushless sensorless. Este tipo de motores eléctricos tienen como característica que no tienen escobillas para cambiar la polaridad del bobinado de su interior y tampoco precisan de un sensor que indique que ha realizado una vuelta. Los motores brushless que son controlados por este tipo de circuitos son específicos para aeronaves no tripuladas y requieren un diseño diferente a un motor brushless pe...
Institute of Scientific and Technical Information of China (English)
Kang, Liping; Jiang, Yishu; Tang, Xiuhua; Yang, Mingyang; Liu, Zonghuai
2012-01-01
One-dimensional manganese oxide nanobelt bundles with birnessite-type structure have been synthesized by a hydrothermal process in a NaOH solution employing K-type layered manganese oxide as a precursor. The obtained manganese oxide nanobelt bundles exhibit excellent discharge properties and cycle stability. The initial capacity is 376 mAh-g-1 and the reversible capacity of 243 mAhog-1 is maintained after the 50th cycle at a current density of 20 mA·g-t. Meanwhile, the manganese oxide nanobelt bundles show an excellent cycle performance even if at relative high current density.
N=2 Heterotic-Type II duality and bundle moduli
Alexandrov, Sergei; Pioline, Boris; Valandro, Roberto
2014-01-01
Heterotic string compactifications on a $K3$ surface $\\mathfrak{S}$ depend on a choice of hyperk\\"ahler metric, anti-self-dual gauge connection and Kalb-Ramond flux, parametrized by hypermultiplet scalars. The metric on hypermultiplet moduli space is in principle computable within the $(0,2)$ superconformal field theory on the heterotic string worldsheet, although little is known about it in practice. Using duality with type II strings compactified on a Calabi-Yau threefold, we predict the form of the quaternion-K\\"ahler metric on hypermultiplet moduli space when $\\mathfrak{S}$ is elliptically fibered, in the limit of a large fiber and even larger base. The result is in general agreement with expectations from Kaluza-Klein reduction, in particular the metric has a two-stage fibration structure, where the $B$-field moduli are fibered over bundle and metric moduli, while bundle moduli are themselves fibered over metric moduli. A more precise match must await a detailed analysis of $R^2$-corrected ten-dimensiona...
Cortactin Adopts a Globular Conformation and Bundles Actin into Sheets
Energy Technology Data Exchange (ETDEWEB)
Cowieson, Nathan P.; King, Gordon; Cookson, David; Ross, Ian; Huber, Thomas; Hume, David A.; Kobe, Bostjan; Martin, Jennifer L. (Queensland); (Aust. Synch.)
2008-08-21
Cortactin is a filamentous actin-binding protein that plays a pivotal role in translating environmental signals into coordinated rearrangement of the cytoskeleton. The dynamic reorganization of actin in the cytoskeleton drives processes including changes in cell morphology, cell migration, and phagocytosis. In general, structural proteins of the cytoskeleton bind in the N-terminal region of cortactin and regulatory proteins in the C-terminal region. Previous structural studies have reported an extended conformation for cortactin. It is therefore unclear how cortactin facilitates cross-talk between structural proteins and their regulators. In the study presented here, circular dichroism, chemical cross-linking, and small angle x-ray scattering are used to demonstrate that cortactin adopts a globular conformation, thereby bringing distant parts of the molecule into close proximity. In addition, the actin bundling activity of cortactin is characterized, showing that fully polymerized actin filaments are bundled into sheet-like structures. We present a low resolution structure that suggests how the various domains of cortactin interact to coordinate its array of binding partners at sites of actin branching.
Cardiac pacing in left bundle branch/ bifascicular block patients
Directory of Open Access Journals (Sweden)
Maddali Madan
2010-01-01
Full Text Available The primary concern in patients with bifascicular block is the increased risk of progression to complete heart block. Further, an additional first-degree A-V block in patients with bifascicular block or LBBB might increase the risk of block progression. Anesthesia, monitoring and surgical techniques can induce conduction defects and bradyarrhythmias in patients with pre-existing bundle branch block. In the setting of an acute MI, several different types of conduction disturbance may become manifest and complete heart block occurs usually in patients with acute myocardial infarction more commonly if there is pre-existing or new bundle branch block. The question that arises is whether it is necessary to insert a temporary pacing catheter in patients with bifascicular block undergoing anesthesia. It is important that an anesthesiologist should be aware of the indications for temporary cardiac pacing as well as the current recommendations for permanent pacing in patients with chronic bifascicular and trifascicular block. This article also highlights the recent guidelines for temporary transvenous pacing in the setting of acute MI and the different pacing modalities that are available for an anesthesiologist.
A four-helix bundle stores copper for methane oxidation.
Vita, Nicolas; Platsaki, Semeli; Baslé, Arnaud; Allen, Stephen J; Paterson, Neil G; Crombie, Andrew T; Murrell, J Colin; Waldron, Kevin J; Dennison, Christopher
2015-09-01
Methane-oxidizing bacteria (methanotrophs) require large quantities of copper for the membrane-bound (particulate) methane monooxygenase. Certain methanotrophs are also able to switch to using the iron-containing soluble methane monooxygenase to catalyse methane oxidation, with this switchover regulated by copper. Methane monooxygenases are nature's primary biological mechanism for suppressing atmospheric levels of methane, a potent greenhouse gas. Furthermore, methanotrophs and methane monooxygenases have enormous potential in bioremediation and for biotransformations producing bulk and fine chemicals, and in bioenergy, particularly considering increased methane availability from renewable sources and hydraulic fracturing of shale rock. Here we discover and characterize a novel copper storage protein (Csp1) from the methanotroph Methylosinus trichosporium OB3b that is exported from the cytosol, and stores copper for particulate methane monooxygenase. Csp1 is a tetramer of four-helix bundles with each monomer binding up to 13 Cu(I) ions in a previously unseen manner via mainly Cys residues that point into the core of the bundle. Csp1 is the first example of a protein that stores a metal within an established protein-folding motif. This work provides a detailed insight into how methanotrophs accumulate copper for the oxidation of methane. Understanding this process is essential if the wide-ranging biotechnological applications of methanotrophs are to be realized. Cytosolic homologues of Csp1 are present in diverse bacteria, thus challenging the dogma that such organisms do not use copper in this location. PMID:26308900
Optimal file-bundle caching algorithms for data-grids
Energy Technology Data Exchange (ETDEWEB)
Otoo, Ekow; Rotem, Doron; Romosan, Alexandru
2004-04-24
The file-bundle caching problem arises frequently in scientific applications where jobs need to process several files simultaneously. Consider a host system in a data-grid that maintains a staging disk or disk cache for servicing jobs of file requests. In this environment, a job can only be serviced if all its file requests are present in the disk cache. Files must be admitted into the cache or replaced in sets of file-bundles, i.e. the set of files that must all be processed simultaneously. In this paper we show that traditional caching algorithms based on file popularity measures do not perform well in such caching environments since they are not sensitive to the inter-file dependencies and may hold in the cache non-relevant combinations of files. We present and analyze a new caching algorithm for maximizing the throughput of jobs and minimizing data replacement costs to such data-grid hosts. We tested the new algorithm using a disk cache simulation model under a wide range of conditions such as file request distributions, relative cache size, file size distribution, etc. In all these cases, the results show significant improvement as compared with traditional caching algorithms.
Capillary bundle model of hydraulic conductivity for frozen soil
Watanabe, Kunio; Flury, Markus
2008-12-01
We developed a capillary bundle model to describe water flow in frozen soil. We assume that the soil can be represented as a bundle of cylindrical capillaries. We consider that the freezing point in the capillaries is depressed according to the Gibbs-Thomson effect and that when stable ice forms in a capillary, the ice forms in the center of the capillaries, leaving a circular annulus open for liquid water flow. We use the model to demonstrate how the hydraulic conductivity changes as a function of temperature for both saturated and unsaturated soils, using a sand and two silt loam soils as examples. As temperature decreases, more and more ice forms, and the water flux consequently decreases. In frozen soil near 0°C, water predominantly flows through ice-free capillaries, so that the hydraulic conductivity of frozen soil is similar to that of an unfrozen soil with a water content equal to the unfrozen water content of the frozen soil. At low temperatures, however, ice forms in almost all capillaries, and the hydraulic conductivity of frozen soil is greater than that of unfrozen soil with the same water potential.
Prostaglandins temporally regulate cytoplasmic actin bundle formation during Drosophila oogenesis.
Spracklen, Andrew J; Kelpsch, Daniel J; Chen, Xiang; Spracklen, Cassandra N; Tootle, Tina L
2014-02-01
Prostaglandins (PGs)--lipid signals produced downstream of cyclooxygenase (COX) enzymes--regulate actin dynamics in cell culture and platelets, but their roles during development are largely unknown. Here we define a new role for Pxt, the Drosophila COX-like enzyme, in regulating the actin cytoskeleton--temporal restriction of actin remodeling during oogenesis. PGs are required for actin filament bundle formation during stage 10B (S10B). In addition, loss of Pxt results in extensive early actin remodeling, including actin filaments and aggregates, within the posterior nurse cells of S9 follicles; wild-type follicles exhibit similar structures at a low frequency. Hu li tai shao (Hts-RC) and Villin (Quail), an actin bundler, localize to all early actin structures, whereas Enabled (Ena), an actin elongation factor, preferentially localizes to those in pxt mutants. Reduced Ena levels strongly suppress early actin remodeling in pxt mutants. Furthermore, loss of Pxt results in reduced Ena localization to the sites of bundle formation during S10B. Together these data lead to a model in which PGs temporally regulate actin remodeling during Drosophila oogenesis by controlling Ena localization/activity, such that in S9, PG signaling inhibits, whereas at S10B, it promotes Ena-dependent actin remodeling.
Dislodgement of carbon nanotube bundles under pressure driven flow.
Baowan, Duangkamon; Cox, Barry J; Hill, James M
2010-04-16
Experimental and predicted flow rates through carbon nanotubes vary considerably but generally are reported to be well in excess of that predicted by the conventional Poiseuille flow, and therefore nanotubes embedded in a matrix might provide membranes with exceptional mass transport properties. In this paper, applied mathematical modelling is undertaken to estimate the three forces acting on a nanotube bundle, namely the molecular interaction force, the viscous force, and the static pressure force. In deducing estimates of these forces we introduce a modification of the notion of the effective dead area for a carbon nanotube membrane, and we calculate the total forces necessary to push one or more of the nanotubes out of the bundle, thus creating a channel through which further enhancement of flow may take place. However, careful analysis shows that the nett dislodgement force is entirely independent on the useable flow area, but rather depends only on the total cross-sectional area perpendicular to the flow. This rather surprising result is a consequence of the flow being steady and a balance of the viscous and pressure forces. PMID:20332554
Resolving bundled microtubules using anti-tubulin nanobodies.
Mikhaylova, Marina; Cloin, Bas M C; Finan, Kieran; van den Berg, Robert; Teeuw, Jalmar; Kijanka, Marta M; Sokolowski, Mikolaj; Katrukha, Eugene A; Maidorn, Manuel; Opazo, Felipe; Moutel, Sandrine; Vantard, Marylin; Perez, Frank; van Bergen en Henegouwen, Paul M P; Hoogenraad, Casper C; Ewers, Helge; Kapitein, Lukas C
2015-08-11
Microtubules are hollow biopolymers of 25-nm diameter and are key constituents of the cytoskeleton. In neurons, microtubules are organized differently between axons and dendrites, but their precise organization in different compartments is not completely understood. Super-resolution microscopy techniques can detect specific structures at an increased resolution, but the narrow spacing between neuronal microtubules poses challenges because most existing labelling strategies increase the effective microtubule diameter by 20-40 nm and will thereby blend neighbouring microtubules into one structure. Here we develop single-chain antibody fragments (nanobodies) against tubulin to achieve super-resolution imaging of microtubules with a decreased apparent diameter. To test the resolving power of these novel probes, we generate microtubule bundles with a known spacing of 50-70 nm and successfully resolve individual microtubules. Individual bundled microtubules can also be resolved in different mammalian cells, including hippocampal neurons, allowing novel insights into fundamental mechanisms of microtubule organization in cell- and neurobiology.
Anatomic double-bundle anterior cruciate ligament reconstruction
Institute of Scientific and Technical Information of China (English)
DAI Xue-song
2012-01-01
Objective: To retrospectively evaluate the early results of anatomic double-bundle anterior cruciate ligament (ACL) reconstruction and compare with the results of native ACL of the contralateral knee.Methods: The results of a consecutive series of 118 patients receiving arthroscopic ACL reconstruction were evaluated.Eight patients were lost to the latest follow-up,leaving a total of 110 patients available for study within at least 3 years' clinical follow-up.Among them,63 patients underwent postoperative MRI and CT scan,as well as clinical evaluation.Results: After reconstruction,the knees were stable and pain-free.Mean postoperative Lysholm score was 95.54 in 110 patients after 3 years.CT and MRI assessment showed that the reconstruction centered in the femoral footprint of ACL (n=63).The sagittal ACL angle in the reconstructed ACL (52.16°±2.45°) was much close to that in the contralateral intact ACL (51.31 °±2.18°,P＞0.05).By ACL-Blumensaat line angle analysis,there was no difference between doublebundle reconstructed knees and their contralateral normal knees (4.67°±0.43° vs.4.62°±0.60°,P＞0.05).Conclusion:Anatomic double-bundle ACL reconstruction can place grafts more precisely in the anatomic footprint of the ACL and better restore knee kinematics.
Directory of Open Access Journals (Sweden)
Aadhavi eSridharan
2012-11-01
Full Text Available The aged rhesus macaque exhibits brain atrophy and behavioral deficits similar to normal aging in humans. Here we studied the association between cognitive and motor performance and anatomic and microstructural brain integrity measured with 3T magnetic resonance imaging in aged monkeys. About half of these animals were maintained on moderate calorie restriction, the only intervention shown to delay the aging process in lower animals. T1-weighted anatomic and diffusion tensor images were used to obtain gray matter volume, and fractional anisotropy and mean diffusivity, respectively. We tested the extent to which brain health indexed by gray matter volume, fractional anisotropy, and mean diffusivity were related to executive and motor function, and determined the effect of the dietary intervention on this relationship. We hypothesized that fewer errors on the executive function test and faster motor times would be correlated with higher volume, higher fractional anisotropy, and lower mean diffusivity in frontal areas that mediate executive function, and in motor, premotor, subcortical, and cerebellar areas underlying goal-directed motor behaviors. Higher error percentage on a cognitive conceptual shift task was significantly associated with lower gray matter volume in frontal and parietal cortices, and lower fractional anisotropy in major association fiber bundles. Similarly, slower performance time on the motor task was significantly correlated with lower volumetric measures in cortical, subcortical, and cerebellar areas and decreased fractional anisotropy in several major association fiber bundles. Notably, performance during the acquisition phase of the hardest level of the motor task was significantly associated with anterior mesial temporal lobe volume. Finally, these brain-behavior correlations for the motor task were attenuated in calorie restricted animals compared to controls, indicating a potential protective effect of the dietary
Research on the Pricing of Bundling Information Commodity%信息产品的捆绑定价问题研究
Institute of Scientific and Technical Information of China (English)
毛彦妮; 王刊良; 王龙伟
2003-01-01
This article studies the characteristics of low marginal cost of information commodity and points out that bundling information commodity is surprisingly profitable. After an analysis of the three factors affecting the sales income of bundling information commodity, that is, marginal cost, distribution of consumer' s valuation of bundling commodity and bundling size, a marketing strategy for bundling information commodity is proposed.
Single-shot T1 mapping of the corpus callosum: A rapid characterization of fiber bundle anatomy
Directory of Open Access Journals (Sweden)
Sabine eHofer
2015-05-01
Full Text Available Using diffusion-tensor MRI and fiber tractography the topographic organization of the corpus callosum (CC has been described to comprise 5 segments with fibers projecting into prefrontal (I, premotor and supplementary motor (II, primary motor (III, and primary sensory areas (IV, as well as into parietal, temporal, and occipital cortical areas (V. In order to more rapidly characterize the underlying anatomy of these segments, this study used a novel single-shot T1 mapping method to quantitatively determine T1 relaxation times in the human CC. A region-of-interest analysis revealed a tendency for the lowest T1 relaxation times in the genu and the highest T1 relaxation times in the somatomotor region of the CC. This observation separates regions dominated by myelinated fibers with large diameters (somatomotor area from densely packed smaller axonal bundles (genu with less myelin. The results indicate that characteristic T1 relaxation times in callosal profiles provide an additional means to monitor differences in fiber anatomy, fiber density, and gray matter in respective neocortical areas. In conclusion, rapid T1 mapping allows for a characterization of the axonal architecture in an individual CC in less than 10 s. The approach emerges as a valuable means for studying neocortical brain anatomy with possible implications for the diagnosis of neurodegenerative processes.
Energy Technology Data Exchange (ETDEWEB)
Zinnbauer, M. [Ludwig-Maximilians-Universitaet Muenchen (Germany)
2001-07-01
As most of the electric utilities in Germany have decided by now to adopt the multi-utility strategy for sales promotion in the open electricity market, a questionnaire has been distributed to 1 000 households in order to find out whether product bundling or cross selling in combination with the low-interest product 'electricity' is a good strategy to enlarge the customer basis. EFOplan (Munic University) and the consulting firm Accenture have been in charge of the survey. The results show the current status of insight of household customers and their motives to change supplier, as well as the pattern of demand for product bundling. (orig./CB) [German] Da mittlerweile die meisten EVUs eine Multi-Utility-Strategie anstreben, wurde mittels einer schriftlichen Befragung von 1 000 deutschen Haushalten untersucht, ob die Vermarktung von Zusatz- bzw. Buendelprodukten in Kombination mit dem Low-Interest-Produkt Strom erfolgsversprechend ist. Die Befragung, die von EFOplan (Universitaet Muenchen) in Kooperation mit der Unternehmensberatung Accenture durchgefuehrt wurde, zeigt einerseits den aktuellen Status von Informationsstand und Wechselmotiven beim Stromkauf und andererseits die Bedarfsstruktur im Hinblick auf moegliche Buendelprodukte. (orig.)
Hanakawa, Takashi
2016-03-01
Over the last few decades, motor imagery has attracted the attention of researchers as a prototypical example of 'embodied cognition' and also as a basis for neuro-rehabilitation and brain-machine interfaces. The current definition of motor imagery is widely accepted, but it is important to note that various abilities rather than a single cognitive entity are dealt with under a single term. Here, motor imagery has been characterized based on four factors: (1) motor control, (2) explicitness, (3) sensory modalities, and (4) agency. Sorting out these factors characterizing motor imagery may explain some discrepancies and variability in the findings from previous studies and will help to optimize a study design in accordance with the purpose of each study in the future. PMID:26602980
National Aeronautics and Space Administration — This file contains the output for the Level 1A Motor data (Suggested Usage: MISR SCF processing needs the MISR motor data samples for the analysis of motor...
Incorporating Endmember Variability into Spectral Mixture Analysis Through Endmember Bundles
Bateson, C. Ann; Asner, Gregory P.; Wessman, Carol A.
1998-01-01
Variation in canopy structure and biochemistry induces a concomitant variation in the top-of-canopy spectral reflectance of a vegetation type. Hence, the use of a single endmember spectrum to track the fractional abundance of a given vegetation cover in a hyperspectral image may result in fractions with considerable error. One solution to the problem of endmember variability is to increase the number of endmembers used in a spectral mixture analysis of the image. For example, there could be several tree endmembers in the analysis because of differences in leaf area index (LAI) and multiple scatterings between leaves and stems. However, it is often difficult in terms of computer or human interaction time to select more than six or seven endmembers and any non-removable noise, as well as the number of uncorrelated bands in the image, limits the number of endmembers that can be discriminated. Moreover, as endmembers proliferate, their interpretation becomes increasingly difficult and often applications simply need the aerial fractions of a few land cover components which comprise most of the scene. In order to incorporate endmember variability into spectral mixture analysis, we propose representing a landscape component type not with one endmember spectrum but with a set or bundle of spectra, each of which is feasible as the spectrum of an instance of the component (e.g., in the case of a tree component, each spectrum could reasonably be the spectral reflectance of a tree canopy). These endmember bundles can be used with nonlinear optimization algorithms to find upper and lower bounds on endmember fractions. This approach to endmember variability naturally evolved from previous work in deriving endmembers from the data itself by fitting a triangle, tetrahedron or, more generally, a simplex to the data cloud reduced in dimension by a principal component analysis. Conceptually, endmember variability could make it difficult to find a simplex that both surrounds the data
Directory of Open Access Journals (Sweden)
Guan-Yu Zheng
2014-01-01
Full Text Available Natural fiber bundle like hemp fiber bundle usually includes many small lumens embedded in solid region; thus, it can present lower thermal conduction than that of conventional fibers. In the paper, characteristic of anisotropic transverse thermal conductivity of unidirectional natural hemp fiber bundle was numerically studied to determine the dependence of overall thermal property of the fiber bundle on that of the solid region phase. In order to efficiently predict its thermal property, the fiber bundle was embedded into an imaginary matrix to form a unit composite cell consisting of the matrix and the fiber bundle. Equally, another unit composite cell including an equivalent solid fiber was established to present the homogenization of the fiber bundle. Next, finite element thermal analysis implemented by ABAQUS was conducted in the two established composite cells by applying proper thermal boundary conditions along the boundary of unit cell, and influences of the solid region phase and the equivalent solid fiber on the composites were investigated, respectively. Subsequently, an optional relationship of thermal conductivities of the natural fiber bundle and the solid region was obtained by curve fitting technique. Finally, numerical results from the obtained fitted curves were compared with the analytic Hasselman-Johnson’s results and others to verify the present numerical model.
Unwrapping the Bundle: An Examination of Research Libraries and the "Big Deal"
Strieb, Karla L.; Blixrud, Julia C.
2014-01-01
This study presents and analyzes the findings of a 2012 survey of member libraries belonging to the Association of Research Libraries (ARL) about publishers' large journal bundles and compares the results to earlier surveys. The data illuminate five research questions: market penetration, journal bundle construction, collection format shifts,…
To Be or Not To Be: The Existential Issue for National Governance Bundles
Millar, C.C.J.M.
2014-01-01
Research Question/Issue The article addresses the issue of whether governance bundles which include both formal and informal governance mechanisms should be classified and compared on the basis of national identity. Research Findings/Insights The governance bundle affecting each firm has formal co
A simulation study on the adsorption properties of linear alkanes on closed nanotube bundles
J.J. Cannon; T.J.H. Vlugt; D. Dubbeldam; S. Maruyama; J. Shiomi
2012-01-01
Adsorption onto carbon nanotube bundles may find use in various applications such as gas pre-concentration and separation, and as a result it is of great interest to study the adsorption properties of such bundles. The adsorption of linear alkanes, with their systematic variation through chain lengt
Relationships between the Tensile Properties and Tenacity extension Behaviour of Fibre-bundles
Institute of Scientific and Technical Information of China (English)
YU Wei-dong
2002-01-01
Fibre bundle testing is different from single-fibre measurement, not only in testing methods and instruments, but in the results obtained. For wool fibres, Sirolan-TENSOR can supply fibre-bundle tenacity (BS) and bundle extension (BE), but has some limitations on the analysis of the measured tensile curves of fibre bundles. It has not only raised new parameters,such as initial modulus (BM) and specific work of rupture (BW), as well as the specific work before or after the peak-point(WBP or WAP) and the ratios of WAP/WBP and WAP/BW, but also compared the tensile behaviour of different fibre-bundles, e.g. wool,polyester and viscose rayon fibre- bundles. The experimental results from 32 lots of wool tops show that there are correlations between bundle tensile properties,such as BS-BE, BS-BM, BS-BW, BE-BW and BM-BW.However, the variables of coefficients of variance (CV)are almost independent of each other and have no correlation with the average values of fibre bundle tensile parameters, except for BS-CVBM and CVBM-BW.
Parabolic Bundles on Algebraic Surfaces I -- The Donaldson-Uhlenbeck Compactification
Indian Academy of Sciences (India)
V Balaji; A Dey; R Parthasarathi
2008-02-01
The aim of this paper is to construct the parabolic version of the Donaldson-Uhlenbeck compactification for the moduli space of parabolic stable bundles on an algebraic surface with parabolic structures along a divisor with normal crossing singularities. We prove the non-emptiness of the moduli space of parabolic stable bundles of rank 2.
A Variant of K-Theory and Topological T-Duality for Real Circle Bundles
Gomi, Kiyonori
2015-03-01
For a space with involutive action, there is a variant of K-theory. Motivated by T-duality in type II orbifold string theory, we establish that a twisted version of the variant enjoys a topological T-duality for Real circle bundles, i.e., circle bundles with real structure.
Overview of flowline bundle technology from concept selection to offshore installation
Institute of Scientific and Technical Information of China (English)
Song Ruxin; Xia Qiuling
2013-01-01
Flowline bundle system consisting of carrier pipe,sleeve pipe and internal flowlines offers innovative solution for the infield transportation of oil and gas.Due to its features,flowline bundle offers a couple of advantages over conventional flowline in particular for cases where multi-flowlines and high thermal performance is of great interest.The main benefits and advantages of such system include excellent thermal performance to prevent wax formation and hydrates,multiple bundled flowlines,mechanical and corrosion protection,potential reuse,etc.With the developments of offshore oil and gas industries,more and more hydrocarbon resources are being explored and discovered from shallow to deep water.Pipeline bundle system can be a smart solution for certain applications,which can be safe and cost effective solution.The objective of this paper is to overview pipeline bundle technology,outline detailed engineering design issue and procedure.Focus is given to its potential application in offshore for infield transportation.Engineering design principles and procedures for pipeline bundle system are highlighted.Construction methods of flowline bundle onshore are reviewed.Offshore towing and installation of pipeline bundle procedure is outlined.
Lexical Bundles in Discourse Structure: A Corpus-Based Study of Classroom Discourse
Csomay, Eniko
2013-01-01
The present study applies corpus-based methods to document the distributional patterns of previously reported lexical bundle functions as they relate to discourse structure. Specifically, 84 lexical bundles and their discourse functions (Biber "et al." 2004a) were tracked in 1,176 discourse units extracted from the initial phases of 196 university…
Textbook-Bundled Metacognitive Tools: A Study of LearnSmart's Efficacy in General Chemistry
Thadani, Vandana; Bouvier-Brown, Nicole C.
2016-01-01
College textbook publishers increasingly bundle sophisticated technology-based study tools with their texts. These tools appear promising, but empirical work on their efficacy is needed. We examined whether LearnSmart, a study tool bundled with McGraw-Hill's textbook "Chemistry" (Chang & Goldsby, 2013), improved learning in an…
GPU acceleration of the stochastic grid bundling method for early-exercise options
Leitao Rodriguez, A.; Oosterlee, C.W.
2015-01-01
In this work, a parallel graphics processing units (GPU) version of the Monte Carlo stochastic grid bundling method (SGBM) for pricing multi-dimensional early-exercise options is presented. To extend the method’s applicability, the problem dimensions and the number of bundles will be increased drast
Modification of the Simpson moduli space M_{3m+1}(P_2) by vector bundles (I)
Iena, Oleksandr
2010-01-01
We consider the moduli space of stable vector bundles on curves embedded in P_2 with Hilbert polynomial 3m+1 and construct a compactification of this space by vector bundles. The result is a blow up of the Simpson moduli space M_{3m+1}(P_2).
Cohomology of line bundles on the flag variety for type G_2
DEFF Research Database (Denmark)
Andersen, Henning Haahr; Kaneda, Masaharu
2012-01-01
In the case of a simple algebraic group G of type G2 over a field of characteristic p>0 we study the cohomology modules of line bundles on the flag variety for G. Our main result is a complete determination of the vanishing behavior of such cohomology in the case where the line bundles in question...
Hermitian-Einstein metrics on holomorphic vector bundles over Hermitian manifolds
International Nuclear Information System (INIS)
In this paper, we prove the long-time existence of the Hermitian-Einstein flow on a holomorphic vector bundle over a compact Hermitian (non-kaehler) manifold, and solve the Dirichlet problem for the Hermitian-Einstein equations. We also prove the existence of Hermitian-Einstein metrics for holomorphic vector bundles on a class of complete noncompact Hermitian manifolds. (author)
Cortes, Viviana
2013-01-01
This article presents a group of lexical bundles identified in a corpus of research article introductions as the first step in the analysis of these expressions in the different sections of the research article. A one-million word corpus of research article introductions from various disciplines was compiled and the lexical bundles identified in…
Institute of Scientific and Technical Information of China (English)
YU Wei-dong; Ron Postle; YANG Shou-ren; YAN Hao-jing
2002-01-01
The testing conditions of a fibre bundle tensile tester (TENSOR) are elongation speed (ES), gauge length (GL), pretension, jaw pressure, environmental temperature and relative humidity, instrument linearity and sensitivity. The effects on fibre-bundle tensile properties at different GL and ES have been discussed in detail and compared with Peirce's theories on the weaklinks and the breaking time effect. The experimental results indicate that the tensile properties of fibre bundles are strongly affected by GL and vary with different GL. The reasonable GL should be 5-15mm rather than 3.2mm for wool bundle measurements. The ES ranging from 20mm/min to 40mm/min is beneficial for obtaining comparatively stable and accurate tensile values, whereas 20 mm/min used in current testing for wool fibre bundles is at the lower limit of the suggested range. For bundle modulus measurement, the sampling interval must be selected appropriately. The new calculation of the sampling interval has been established.
Reflood Phenomena in a 5 x 5 Ballooned Rod Bundle
Energy Technology Data Exchange (ETDEWEB)
Kim, Byoung Jae; Kim, Jong Rok; Kim, Kihwan; Moon, S. K. [KAERI, Daejeon (Korea, Republic of)
2015-05-15
Various experimental programs were carried out for the coolability of an assembly containing a partial blockage in a group of ballooned fuel rods under LOCA conditions. A review on these experimental programs is well documented in. One key distinguished feature of KAERI research activities is the consideration of local power increase owing to fuel relocation, whereas the past experimental program did not consider the effect of fuel relocation. The purpose of this study is to investigate the reflood phenomena in the partial blocked 5 x 5 rod bundle. A series of the forced reflood tests were performed with/without consideration of local power increase by fuel relocation. The experimental data were evaluated with numerical predictions using MARS code. The flow blockage alone has little effect on the peak wall temperature. However, the local power increase by fuel relocation affects considerably the peak wall temperature and the time period during which high wall temperatures continue.
Subchannel analysis of CANDU 37-element fuel bundles
International Nuclear Information System (INIS)
The subchannel analysis codes COBRA-IV and ASSERT-4 have been used to predict the mass and enthalpy imbalance within a CANDU 37-element fuel channel under various system conditions. The objective of this study was to assess the various capabilities of the ASSERT code and highlight areas where further validation or development may be needed. The investigation indicated that the ASSERT code has all the basic models required to accurately predict the flow and enthalpy imbalance for complex rod bundles. The study also showed that the code modelling of void drift and diffusion requires refinement to some coefficients and that further validation is needed at high flow rate and high void fraction conditions, where ASSERT and COBRA are shown to predict significantly different trends. The results of a recent refinement of ASSERT modelling are also discussed
Reflood Phenomena in a 5 x 5 Ballooned Rod Bundle
International Nuclear Information System (INIS)
Various experimental programs were carried out for the coolability of an assembly containing a partial blockage in a group of ballooned fuel rods under LOCA conditions. A review on these experimental programs is well documented in. One key distinguished feature of KAERI research activities is the consideration of local power increase owing to fuel relocation, whereas the past experimental program did not consider the effect of fuel relocation. The purpose of this study is to investigate the reflood phenomena in the partial blocked 5 x 5 rod bundle. A series of the forced reflood tests were performed with/without consideration of local power increase by fuel relocation. The experimental data were evaluated with numerical predictions using MARS code. The flow blockage alone has little effect on the peak wall temperature. However, the local power increase by fuel relocation affects considerably the peak wall temperature and the time period during which high wall temperatures continue
Cap assembly for a bundled tube fuel injector
Energy Technology Data Exchange (ETDEWEB)
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.
Ion-irradiation-induced defects in bundles of carbon nanotubes
Salonen, E; Nordlund, K
2002-01-01
We study the structure and formation yields of atomic-scale defects produced by low-dose Ar ion irradiation in bundles of single-wall carbon nanotubes. For this, we employ empirical potential molecular dynamics and simulate ion impact events over an energy range of 100-1000 eV. We show that the most common defects produced at all energies are vacancies on nanotube walls, which at low temperatures are metastable but long-lived defects. We further calculate the spatial distribution of the defects, which proved to be highly non-uniform. We also show that ion irradiation gives rise to the formations of inter-tube covalent bonds mediated by carbon recoils and nanotube lattice distortions due to dangling bond saturation. The number of inter-tube links, as well as the overall damage, linearly grows with the energy of incident ions.
MENT reconstruction and potting comparison of a LMFBR fuel bundle
International Nuclear Information System (INIS)
Since the advent of computer-assisted-tomography (CAT), the CAT techniques have been rapidly expanded to the nuclear industry. A number of investigators have applied these techniques to reconstruct the fuel bundle configuration inside a subassembly with various degrees of resolution; however, there has been little data available on the accuracy of these reconstructions, and no comparisons have been made with the internal structure of actual irradiated subassemblies. Some efforts have utilized pretest mock-ups to calibrate the CAT algorithms, but the resulting mock-up configurations do not necessarily represent an actual subassembly, so an exact comparison has been lacking. The purpose of this paper is to present the results of a comparison between a CAT reconstruction of an irradiated subassembly and the destructive examination of the same subassembly
Treatment, packaging, and storage of bundle scrap hardware
International Nuclear Information System (INIS)
A study was performed to identify and evaluate the various technical options for treatment, packaging and storing the bundle scrap hardware that results from rod consolidation. The three general scenarios addressed were keeping the treated scrap in the pool, moving it to on-site dry storage, or immediate disposal. The study concluded that practical alternatives existed for all three cases. Use of novel scrap packaging techniques achieved an overall net consolidation ratio of two. The most economical concept was found to be using advanced technology in the pool storage scenario with dry storage schemes a close second. The project also provides information on scrap characterization and provides tools to assist in classifying the scrap hardware
Structural evaluation of a DTHR bundle divertor particle collector
International Nuclear Information System (INIS)
The purpose of this report is to present a structural evaluation of the current bundle divertor particle collector BDPC design under a peak heat flux in relation to criteria that protect against coolant leakage into the plasma over replacement schedules planned during DTHR operation. In addition, an assessment of the BDPC structural integrity at higher heat fluxes is presented. Further, recommendations for modifications in the current BDPC design that would improve design reliability to be considered in future design studies are described. Finally, experimental test programs directed to establishing materials data necessary in providing greater confidence in subsequent structural evaluations of BDPC designs in relation to coolant leakage over planned replacement schedules are identified
Heat-transfer augmentation in rod bundles near grid spacers
International Nuclear Information System (INIS)
Heat-transfer augmentation by straight grid spacers in rod bundles is studied for single-phase flow and for post-critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single-phase flow is also examined. Governing heat-transfer mechanisms are analyzed, and predictive formulations are established. For single-phase flow, the local heat transfer at a straight spacer and at its upstream or downstream locations are treated separately. The effect of local velocity increasing near swirling spacer is considered. For post critical heat flux (CHF) dispersed flow, the heat transfer by thermal radiation, fin cooling, and vapor convection near the spacer are calculated. The predictions are compared with experimental data with satisfactory agreement
Flow-induced vibration of steam generator tube bundles
International Nuclear Information System (INIS)
The vibrations induced in tube arrays by a transversal flow are of great practical interest because of their destructive effects especially on heat exchangers. Instabilities can appear beyond a critical flow velocity and induce very high vibratory levels which may involve fractures. These instabilities involve a fluidelastic coupling between the vibratory movement of the tubes and the flow round them. Studies are being carried out in France concerning steam generators. A lot of bundle mock-ups with various pitches have been tested and large range parameter domains have been investigated. In a second part, the C.E.A., FRAMATOME, E.D.F. and WESTINGHOUSE research program, which is being carried out, is presented
Dynamic Model and Motion Mechanism of Magnetotactic Bacteria with Two Lateral Flagellar Bundles
Institute of Scientific and Technical Information of China (English)
Cenyu Yang; Chuanfang Chen; Qiufeng Ma; Longfei Wu; Tao Song
2012-01-01
Magnetotactic Bacteria (MTB) propel themselves by rotating their flagella and swim along the magnetic field lines.To analyze the motion of MTB,MTB magneto-ovoid strain MO-1 cells,each with two bundles of flagella,were taken as research object.The six-degrees-of-freedom (6-DoF) dynamic model of MO-1 was established based on the Newton-Euler dynamic equations.In particular,the interaction between the flagellum and fluid was considered by the resistive force theory.The simulated motion trajectory of MTB was found to consist of two kinds of helices:small helices resulting from the imbalance of force due to flagellar rotation,and large helices arising from the different directions of the rotation axis of the cell body and the propulsion axis of the flagellum.The motion behaviours of MTB in various magnetic fields were studied,and the simulation results agree well with the experiment results.In addition,the rotation frequency of the flagella was estimated at 1100 Hz,which is consistent with the average rotation rate for Na+-driven flagellar motors.The included angle of the magnetosome chain was predicted at 40° that is located within 20° to 60° range of the observed results.The results indicate the correctness of the dynamic model,which may aid research on the operation and control of MTB-propelled micro-actuators.Meanwhile,the motion behaviours of MTB may inspire the development of micro-robots with new driving mechanisms.
Komzák, M; Hart, R; Smíd, P; Puskeiler, M
2014-01-01
PURPOSE OF THE STUDY A comparison of the efficacy of central anatomical single-bundle (CASB) reconstruction with that of double-bundle (DB) repair of the anterior cruciate ligament (ACL) in relation to knee stability in anteroposterior translation (APT), internal rotation (IR) and external rotation (ER) of the joint. MATERIAL AND METHODS A total of 40 patients were evaluated; 20 had ACL reconstruction by the CASB technique using hamstrings and 20 underwent DB repair surgery. The average age was 31.3 years, and the group included 22 men and 18 women with 19 right and 21 left knees. The KT-1000 test was used to assess the amount of APT in the knee and rotational deviations were measured by the Rolimeter. In the DB patients, measurements were performed before surgery (on joints with ACL injury), then after reconstruction of the anteromedial (AM) or the posterolateral (PL) bundle and subsequently after repair of both ACL bundles. The CASB patients were assessed before and after graft insertion. RESULTS The average APT value was 18.5 mm for the pre-operative knees and it fell to 8.9 mm after AM bundle reconstruction. However, when the PL bundle was inserted in the first place, the average APT value was 13.1 mm only. The average values recorded after the DB and CASB reconstructions were 6.1 mm and 9.1 mm, respectively. The average IR range of motion in the pre-operative joints was 18.6 degrees. After AM bundle reconstruction it was 13.9 degrees and after PL bundle repair it was 15.3 degrees. In DB reconstruction the average IR value achieved 10.4 degrees, and in CASB repair surgery it was 13.7 degrees. The average ER range of motion in the pre-operative joints was 17.8 degrees. After AM bundle reconstruction it was 14.5 degrees and after PL bundle repair it was 14.9 degrees. In DB reconstruction the average ER value achieved 11.4 degrees, and in CASB repair surgery it was 14.5 degrees. DISCUSSION Rotational stability of the knee after ACL reconstruction is one of the
Improve Motor System Efficiency for a Broad Range of Motors with MotorMaster+ International
Energy Technology Data Exchange (ETDEWEB)
None
2005-05-01
Available at no charge, MotorMaster+ International is designed to support motor systems improvement planning at industrial facilities by identifying the most cost-effective choice when deciding to repair or replace older motor models.
Numerical Hermitian Yang-Mills Connections and Vector Bundle Stability in Heterotic Theories
Anderson, Lara B; Karp, Robert L; Ovrut, Burt A
2010-01-01
A numerical algorithm is presented for explicitly computing the gauge connection on slope-stable holomorphic vector bundles on Calabi-Yau manifolds. To illustrate this algorithm, we calculate the connections on stable monad bundles defined on the K3 twofold and Quintic threefold. An error measure is introduced to determine how closely our algorithmic connection approximates a solution to the Hermitian Yang-Mills equations. We then extend our results by investigating the behavior of non slope-stable bundles. In a variety of examples, it is shown that the failure of these bundles to satisfy the Hermitian Yang-Mills equations, including field-strength singularities, can be accurately reproduced numerically. These results make it possible to numerically determine whether or not a vector bundle is slope-stable, thus providing an important new tool in the exploration of heterotic vacua.
The dual specificity phosphatase Cdc14B bundles and stabilizes microtubules
Energy Technology Data Exchange (ETDEWEB)
Plumley, Hyekyung [ORNL; Liu, Yie [ORNL; Gomez, Marla V [ORNL; Wang, Yisong [ORNL
2005-01-01
The Cdc14 dual-specificity phosphatases regulate key events in the eukaryotic cell cycle. However, little is known about the function of mammalian CDC14B family members. Here, we demonstrate that subcellular localization of CDC14B protein is cell cycle regulated. CDC14B can bind, bundle, and stabilize microtubules in vitro independently of its catalytic activity. Basic amino acid residues within the nucleolar targeting domain are important for both retaining CDC14B in the nucleolus and preventing microtubule bundling. Overexpression of CDC14B resulted in the formation of cytoplasmic CDC14B and microtubule bundles in interphase cells. These microtubule bundles were resistant to microtubule depolymerization reagents and enriched in acetylated -tubulin. Expression of cytoplasmic forms of CDC14B impaired microtubule nucleation from the microtubule organization center. CDC14B is thus a novel microtubule-bundling and -stabilizing protein, whose regulated subcellular localization may help modulate spindle and microtubule dynamics in mitosis.
Characteristics of liquid and boiling sodium flows in heating pin bundles
International Nuclear Information System (INIS)
This study is related to cooling accidents which could occur in sodium cooled fast reactors. Thermo-hydraulic aspects of boiling experiments in pin bundles with helical wire-wrap spacer systems, in the case of undamaged geometries, are analyzed. Differences and analogies in the behavior of multi-rod bundle flows and one-dimensional channel flows are studied. A boiling model is developed for bundle geometries, and predictions obtained with the FLICA code using this models are presented. These predictions are compared with experimental results obtained in a water 19-rod bundle. Then, results of sodium boiling experiments through a 19-rod bundle are interpreted. Both cases of high power and reduced power are envisaged
Single and two-phase flow pressure drop for CANFLEX bundle
Energy Technology Data Exchange (ETDEWEB)
Park, Joo Hwan; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Dimmick, G. R.; Bullock, D. E. [Atomic Energy of Canada Limited, Ontario (Canada)
1998-12-31
Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-134a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLEX bundle is found to be about 20% higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within {+-} 5% error. 11 refs., 5 figs. (Author)
THE COCHLEAR AMPLIFIER：IS IT HAIR BUNDLE MOTION OF OUTER HAIR CELLS?
Institute of Scientific and Technical Information of China (English)
LI Yi; He David Z
2014-01-01
Cochlear outer hair cells (OHCs) are involved in a mechanical feedback loop in which the fast somatic motility of OHCs is required for cochlear amplification. Alternatively, amplification is thought to arise from active hair bundle movements ob-served in non-mammalian hair cells. We measured the voltage-evoked hair bundle motions in the gerbil cochlea to determine if such movements are also present in mammalian OHCs. The OHCs displayed a large hair bundle movement that was not based on mechanotransducer channels but based on somatic motility. Significantly, bundle movements were able to generate radial motion of the tectorial membrane in situ. This result implies that the motility-associated hair bundle motion may be part of the cochlear amplifier.
Fracture process of a fiber bundle with strong disorder
Danku, Zsuzsa; Kun, Ferenc
2016-07-01
We investigate the effect of the amount of disorder on the fracture process of heterogeneous materials in the framework of a fiber bundle model. The limit of high disorder is realized by introducing a power law distribution of fiber strength over an infinite range. We show that on decreasing the amount of disorder by controlling the exponent of the power law the system undergoes a transition from the quasi-brittle phase where fracture proceeds in bursts to the phase of perfectly brittle failure where the first fiber breaking triggers a catastrophic collapse. For equal load sharing in the quasi-brittle phase the fat tailed disorder distribution gives rise to a homogeneous fracture process where the sequence of breaking bursts does not show any acceleration as the load increases quasi-statically. The size of bursts is power law distributed with an exponent smaller than the usual mean field exponent of fiber bundles. We demonstrate by means of analytical and numerical calculations that the quasi-brittle to brittle transition is analogous to continuous phase transitions and determine the corresponding critical exponents. When the load sharing is localized to nearest neighbor intact fibers the overall characteristics of the failure process prove to be the same, however, with different critical exponents. We show that in the limit of the highest disorder considered the spatial structure of damage is identical with site percolation—however, approaching the critical point of perfect brittleness spatial correlations play an increasing role, which results in a different cluster structure of failed elements.
Load sharing in the growth of bundled biopolymers
Wang, Ruizhe; Carlsson, A. E.
2014-01-01
To elucidate the nature of load sharing in the growth of multiple biopolymers, we perform stochastic simulations of the growth of biopolymer bundles against obstacles under a broad range of conditions and varying assumptions. The obstacle motion due to thermal fluctuations is treated explicitly. We assume the “Perfect Brownian Ratchet” (PBR) model, in which the polymerization rate equals the free-filament rate as soon as the filament-obstacle distance exceeds the monomer size. Accurate closed-form formulas are obtained for the case of a rapidly moving obstacle. We find the following: (1) load sharing is usually sub-perfect in the sense that polymerization is slower than for a single filament carrying the same average force; (2) the sub-perfect behavior becomes significant at a total force proportional to the logarithm or the square root of the number of filaments, depending on the alignment of the filaments; (3) for the special case of slow barrier diffusion and low opposing force, an enhanced obstacle velocity for an increasing number of filaments is possible; (4) the obstacle velocity is very sensitive to the alignment of the filaments in the bundle, with a staggered alignment being an order of magnitude faster than an unstaggered one at forces of only 0.5 pN per filament for 20 filaments; (5) for large numbers of filaments, the power is maximized at a force well below 1 pN per filament; (6) for intermediate values of the obstacle diffusion coefficient, the shape of the force velocity relation is very similar to that for rapid obstacle diffusion. PMID:25489273
Measuring ambient radon using a scintillating optical fiber bundle
International Nuclear Information System (INIS)
Complete text of publication follows. Several years ago a new approach to monitoring radon and its radioactive progeny using a bundle of scintillating optical fibers was introduced, and studies on the characteristics of this detector were reported. It was demonstrated that a bundle of thin optical fibers constructed from a scintillating glass could serve as a detector of radon in air by providing a large accessible surface area and a means of trapping and concentrating radon gas so as to increase the effective contact time between the radon and the scintillating material. We now report the first ambient radon measurements made with this detector. Details of the sensor construction will be supplied and diagrammed. Briefly, several thousand scintillating glass fibers are packed into a 6 mm i.d. quartz tube through which radon-laden ambient air is drawn. Light produced by the interaction of alpha particles from radon and its radioactive progeny is directed by a reflector onto a photomultiplier tube, and the resulting pulses are sorted and displayed by a multichannel scalar. The instrument has been used in laboratory studies, and in field measurements at a location in Slovenia with high radon levels. Radon was simultaneously monitored in the same location using an Alphaguard radon monitor, which is a commercial passive ionization chamber instrument. It was found that the fiber optic sensor detected ambient radon with a sensitivity of approximately 50 counts per minute per Bq per liter of air. Since the sensitive volume is only 1 ml. we conclude that significant concentration of radon on the the sensor is occurring. These results will be presented and discussed
Energy Technology Data Exchange (ETDEWEB)
Todreas, N.E.; Golay, M.W.; Wolf, L.
1981-02-01
Four tasks are reported: bundle geometry (wrapped and bare rods), subchannel geometry (bare rods), subchannel geometry (bare rods), LMFBR outlet plenum flow mixing, and theoretical determination of local temperature fields in LMFBR fuel rod bundles. (DLC)
Directory of Open Access Journals (Sweden)
Mousavi Hamid
2012-01-01
Full Text Available Background: Initial fixation strength is critical for the early post-operative rehabilitation of patients with anterior cruciate ligament (ACL reconstructions. However, even the best femoral fixation devices remain controversial. We compared the results of 2 of the femoral fixation techniques,Rigidfix and Transfix. Materials and Methods: A total of 30 patients with unilateral ACL deficiency were randomly assigned to 1 of 2 groups. In Group A an anatomic single-bundle ACL reconstruction was performed using Rigidfix technique(Mitek, Norwood,MA, Group B were treated by a single bundle using Transfix technique(Arthrex, Naples, FL, USA. For tibial fixation, a bioabsorbable Intrafix interference screw was used for all the groups and the graft was fashioned from the semitendinosus and gracilis tendons in all patients. The patients were subjected to a clinical evaluation, with assessment of the anterior drawer, Lachman′s and the pivot-shift tests. They also completed the International Knee Documentation Committee (IKDC score. Results: At a mean of 14 months (12-17 followup there were no significant differences concerning time between injury and range of movement between the 2 groups. However, the Rigidfix group showed significantly better results for the subjective assessment of knee function ( P = 0.002. The Lachman, anterior drawer, and pivot-shift tests also showed no significant difference between the 2 groups. The IKDC scale showed no significant difference among the groups ( P < 0.001.There was no difference regarding duration of operation and cost of the operation between the 2 groups.On clinical evaluation there was no significant difference between the 2 groups. However, regardless of the technique, all knees were improved by ACL reconstruction compared with their preoperative status. Conclusion: Both techniques can be used for reconstruction of ACL. Other factors, such as psychic profile of the patients should be considered for surgery
System and method for motor parameter estimation
Energy Technology Data Exchange (ETDEWEB)
Luhrs, Bin; Yan, Ting
2014-03-18
A system and method for determining unknown values of certain motor parameters includes a motor input device connectable to an electric motor having associated therewith values for known motor parameters and an unknown value of at least one motor parameter. The motor input device includes a processing unit that receives a first input from the electric motor comprising values for the known motor parameters for the electric motor and receive a second input comprising motor data on a plurality of reference motors, including values for motor parameters corresponding to the known motor parameters of the electric motor and values for motor parameters corresponding to the at least one unknown motor parameter value of the electric motor. The processor determines the unknown value of the at least one motor parameter from the first input and the second input and determines a motor management strategy for the electric motor based thereon.
Araki, Daisuke; Kuroda, Ryosuke; Kubo, Seiji; Fujita, Norifumi; Tei, Katsumasa; Nishimoto, Koji; Hoshino, Yuichi; Matsushita, Takehiko; Matsumoto, Tomoyuki; Nagamune, Koki; Kurosaka, Masahiro
2011-03-01
We conducted a prospective randomised study of anatomical single-bundle (A-SB group) versus double-bundle (A-DB group) anterior cruciate ligament (ACL) reconstruction using the hamstrings tendons. Twenty patients with unilateral ACL deficiency were randomised into two groups. We created the bone tunnels at the position of the original insertion of the anteromedial bundle footprint and posterolateral bundle footprint in the A-DB group and at the central position between these two bundles in the A-SB group. All of the patients were tested before ACL reconstruction and one year after surgery. The KT-1000 measurements, isokinetic muscle peak torque and heel-height difference were evaluated and the general knee condition was assessed by Lysholm score. For pre- and postoperative stability assessment, we used the six-degrees-of-freedom of knee kinematic measurement system using an electromagnetic device (the EMS) for quantitative assessment during the Lachman test and the pivot shift test. There were no significant differences in the KT-1000 measurements, isokinetic muscle peak torque, heel-height difference, and Lysholm score at one-year follow-up between these two groups. The EMS data showed there were significant differences in the acceleration of the pivot shift test between the operated knee and the contralateral normal knees in the A-SB group. In conclusion, clinical outcomes were equally good in both groups. However, the EMS data showed the anatomical double-bundle ACL reconstruction tended to be biomechanically superior to the single-bundle reconstruction.
... these crashes is one part of motor vehicle safety. Here are some things you can do to ... speed or drive aggressively Don't drive impaired Safety also involves being aware of others. Share the ...
Congenital Ocular Motor Apraxia
Directory of Open Access Journals (Sweden)
J Gordon Millichap
2007-06-01
Full Text Available The clinical and neuroradiological findings, and long-term intellectual prognosis in 10 patients (4 boys and 6 girls with congenital ocular motor apraxia (COMA are reviewed by researchers at Tottori University, Yonago, Japan.
Partial motor status epilepticus
Gilberto Rebello de Mattos; José C. Rollemberg Filho
1992-01-01
We report the case of a young female patient with photosensitive primary epilepsy who presented partial motor status epilepticus provoked by the act of shutting the eyes. Clinical, EEG and neuroimage data are presented and discussed.
Congenital Ocular Motor Apraxia
J Gordon Millichap
2007-01-01
The clinical and neuroradiological findings, and long-term intellectual prognosis in 10 patients (4 boys and 6 girls) with congenital ocular motor apraxia (COMA) are reviewed by researchers at Tottori University, Yonago, Japan.
Nonautistic Motor Stereotypies
J Gordon Millichap
2008-01-01
Clinical features and long-term outcomes of 100 children (62 boys and 35 girls) with motor stereotypies were evaluated by review of records and telephone interviews at Johns Hopkins Hospital, Baltimore, MD.
Heritability of motor control and motor learning
Missitzi, Julia; Gentner, Reinhard; Misitzi, Angelica; Geladas, Nickos; Politis, Panagiotis; Klissouras, Vassilis; Classen, Joseph
2013-01-01
Abstract The aim of this study was to elucidate the relative contribution of genes and environment on individual differences in motor control and acquisition of a force control task, in view of recent association studies showing that several candidate polymorphisms may have an effect on them. Forty‐four healthy female twins performed brisk isometric abductions with their right thumb. Force was recorded by a transducer and fed back to the subject on a computer screen. The task was to place the...
Schellekens, Johannes Maria Hubertus
1985-01-01
In this thesis, the results of a series of investigations into the barrier function of human skin are presented. In these investigations, the barrier function was assessed by water vapour loss measurements of the skin using a method based on gradient estimation. The aim of this thesis is to study the role and efficiency of motor control and anticipation processes in the development of children with and without disturbances in the motor system. Chapter I is a general introduction to the subjec...
Congenital ocular motor apraxia
Carrasquinho, S; Teixeira, S.; Cadete, A; Bernardo, M.; Pêgo, P; Prieto, I.
2008-01-01
PURPOSE: Congenital ocular motor apraxia is a rare disease characterized by defective or absent voluntary and optically induced horizontal saccadic movements. Jerky head movements or thrusts on attempted lateral gaze are a compensatory sign. Most affected children have delayed motor and speech development. Cases associated with systemic diseases, neurologic maldevelopment, metabolic deficits, and chromosomal abnormalities have been described. METHODS: Case report and review of the scienti...
Talbot, K.
2002-01-01
Motor neurone disease (MND), or amyotrophic lateral sclerosis (ALS), is a neurodegenerative disorder of unknown aetiology. Progressive motor weakness and bulbar dysfunction lead to premature death, usually from respiratory failure. Confirming the diagnosis may initially be difficult until the full clinical features are manifest. For all forms of the disease there is a significant differential diagnosis to consider, including treatable conditions, and therefore specialist neurological opinion ...
Gomez-Marin, A.; Sancho, J. M.
2004-01-01
In this paper we present a model of a symmetric Brownian motor (SBM) which changes the sign of its velocity when the temperature gradient is inverted. The velocity, external work and efficiency are studied as a function of the temperatures of the baths and other relevant parameters. The motor shows a current reversal when another parameter (a phase shift) is varied. Analytical predictions and results from numerical simulations are performed and agree very well. Generic properties of this type...
Thy P Nguyen; Vinay Chaudhry
2011-01-01
Multifocal motor neuropathy (MMN) is a unique disorder characterized by slowly progressive, asymmetric, distal and upper limb predominant weakness without significant sensory abnormalities. Electrophysiology is crucial to the diagnosis, revealing the hallmark partial conduction block. MMN is considered immune mediated due to the association with anti-GM1 antibodies and the response to immunomodulatory treatment. It is paramount to recognize MMN from other motor neuronopathies or peripheral ne...
Gerhardsson, Daniel
2010-01-01
Starter motors are sensitive for overheating. By estimating the temperature and preventing cranking in time, there is an option to avoid the dangerous temperatures. The truck manufacturer Scania CV AB proposed a master thesis that should evaluate the need of an overheating protection for the starter motor. The aim is to evaluate any positive effects of implementing an algorithm that can estimate the brush temperature instead of using the available time constrain, which allows 35 seconds of cr...
Institute of Scientific and Technical Information of China (English)
CHENG Shen; SUN Feng-zhong; SHI Yue-tao
2012-01-01
To develop an excellent heat transfer element under the vacuum condition,experiments about the heat transfer performance of horizontal tube bundles of different materials under various vacuum conditions were carried out,including the stainless steel tube,the brass tube,the Ni-based implanted steel tube and the ion implanted brass tube.The relative trends show that the condensation heat transfer coefficient and the overall heat transfer coefficient of bundles of four materials all increase with the vacuum degree,especially,those of the Ni-based implanted steel tube and the ion implanted brass tube.Under a high vacuum condition (0.07 MPa),the condensation heat transfer coefficient of the Ni-based implanted steel tube bundle is about 1.4 times of that of the stainless steel tube bundle,the condensation heat transfer coefficient of the ion implanted brass tube bundle is found to be about 1.3 times of that of the common brass tube bundle.Therefore,according to the condensation heat transfer characteristics studied under high vacuum conditions,it is believed that a dropwise condensation is partly achieved on the surface of these two implanted tube bundles,and the ion implantation is shown to be an effective method to achieve the dropwise condensation.Based on this study,it is believed that the Ni-based steel tube may replace the brass tube,which is more expensive as a heat transfer component.