WorldWideScience

Sample records for braided polymer tubes

  1. Whole shaft visibility and mechanical performance for active MR catheters using copper-nitinol braided polymer tubes

    Directory of Open Access Journals (Sweden)

    McVeigh Elliot R

    2009-08-01

    Full Text Available Abstract Background Catheter visualization and tracking remains a challenge in interventional MR. Active guidewires can be made conspicuous in "profile" along their whole shaft exploiting metallic core wire and hypotube components that are intrinsic to their mechanical performance. Polymer-based catheters, on the other hand, offer no conductive medium to carry radio frequency waves. We developed a new "active" catheter design for interventional MR with mechanical performance resembling braided X-ray devices. Our 75 cm long hybrid catheter shaft incorporates a wire lattice in a polymer matrix, and contains three distal loop coils in a flexible and torquable 7Fr device. We explored the impact of braid material designs on radiofrequency and mechanical performance. Results The incorporation of copper wire into in a superelastic nitinol braided loopless antenna allowed good visualization of the whole shaft (70 cm in vitro and in vivo in swine during real-time MR with 1.5 T scanner. Additional distal tip coils enhanced tip visibility. Increasing the copper:nitinol ratio in braiding configurations improved flexibility at the expense of torquability. We found a 16-wire braid of 1:1 copper:nitinol to have the optimum balance of mechanical (trackability, flexibility, torquability and antenna (signal attenuation properties. With this configuration, the temperature increase remained less than 2°C during real-time MR within 10 cm horizontal from the isocenter. The design was conspicuous in vitro and in vivo. Conclusion We have engineered a new loopless antenna configuration that imparts interventional MR catheters with satisfactory mechanical and imaging characteristics. This compact loopless antenna design can be generalized to visualize the whole shaft of any general-purpose polymer catheter to perform safe interventional procedures.

  2. Energy absorption of braided composite tubes

    Science.gov (United States)

    Beard, Shawn Joseph

    In this investigation, a model was developed for simulating the crushing behavior and predicting the energy absorption characteristics of braided composite tubes. The crushing model uses the finite element code ABAQUS along with a material module that describes the constitutive behavior of the braid material. The material module contains a three-dimensional description of the braid geometry, which is used to calculate the effective stiffnesses of a representative volume. The stiffness calculations include the effects of nonlinear shear, damage accumulation, and scissoring and jamming of the braider tows. A stiffness reduction scheme, based on the predicted failure mode, is used to account for tow and resin failure throughout the representative volume. Scissoring of the braider tows results in an increase in the overall effective compliance until jamming occurs. To facilitate the model development, extensive coupon tests and tube crushing experiments were conducted. Coupon tests were conducted on braided flat plaques to help characterize the damage mechanisms occurring and to obtain the initial stiffnesses for verifying the proposed model. The braided flat plaques were made using 80k Akzo Nobel Fortafil carbon fiber tows for both the axial and braider tows, and Hetron 922 epoxy-vinyl ester resin for the matrix. Crushing tests were conducted on braided carbon fiber/epoxy-vinyl ester composite tubes with both circular and square cross-sections. All tests were conducted quasi-statically, and plug-type initiators were used to trigger the progressive crushing. The braided tubes were made using 80k Akzo Nobel Fortafil carbon fiber tows for the axial tows, 12k Hercules Grafil 34-700 carbon fiber tows for the braider tows, and Hetron 922 epoxy-vinyl ester resin for the matrix. The energy absorption characteristics are significantly affected by the fiber architecture of the tube and the fillet radius of the initiator plug. In order to verify the proposed model, simulation

  3. Mechanical properties of SiC/SiC braided tubes for fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Rohmer, Eric [Laboratoire des Composites Thermostructuraux, UMR 5801, Université de Bordeaux, 3 Allée de la Boétie, 33600 Pessac (France); Martin, Eric, E-mail: martin@lcts.u-bordeaux1.fr [Laboratoire des Composites Thermostructuraux, UMR 5801, Université de Bordeaux, 3 Allée de la Boétie, 33600 Pessac (France); Lorrette, Christophe [Commissariat à l’Energie Atomique et aux énergies Alternatives, CEA, DEN, SRMA, LTMEx, F-91191 Gif-sur-Yvette cedex (France)

    2014-10-15

    Axial and hoop tensile tests are performed at room temperature on SiC fiber CVI matrix tubular samples. A layer-to-layer interlock 3D braided preform is used. An elastic damageable mechanical behavior resulting from the development of matrix and delamination cracks is evidenced. A weaker behavior is observed in the hoop direction as a consequence of the geometry of the fibrous preform. It is shown that a numerical approach can be used to establish a link between the mechanical behavior and the microstructure of the composite.

  4. Development of a Subcell Based Modeling Approach for Modeling the Architecturally Dependent Impact Response of Triaxially Braided Polymer Matrix Composites

    Science.gov (United States)

    Sorini, Chris; Chattopadhyay, Aditi; Goldberg, Robert K.; Kohlman, Lee W.

    2016-01-01

    Understanding the high velocity impact response of polymer matrix composites with complex architectures is critical to many aerospace applications, including engine fan blade containment systems where the structure must be able to completely contain fan blades in the event of a blade-out. Despite the benefits offered by these materials, the complex nature of textile composites presents a significant challenge for the prediction of deformation and damage under both quasi-static and impact loading conditions. The relatively large mesoscale repeating unit cell (in comparison to the size of structural components) causes the material to behave like a structure rather than a homogeneous material. Impact experiments conducted at NASA Glenn Research Center have shown the damage patterns to be a function of the underlying material architecture. Traditional computational techniques that involve modeling these materials using smeared homogeneous, orthotropic material properties at the macroscale result in simulated damage patterns that are a function of the structural geometry, but not the material architecture. In order to preserve heterogeneity at the highest length scale in a robust yet computationally efficient manner, and capture the architecturally dependent damage patterns, a previously-developed subcell modeling approach where the braided composite unit cell is approximated as a series of four adjacent laminated composites is utilized. This work discusses the implementation of the subcell methodology into the commercial transient dynamic finite element code LS-DYNA (Livermore Software Technology Corp.). Verification and validation studies are also presented, including simulation of the tensile response of straight-sided and notched quasi-static coupons composed of a T700/PR520 triaxially braided [0deg/60deg/-60deg] composite. Based on the results of the verification and validation studies, advantages and limitations of the methodology as well as plans for future work

  5. Visual classification of braided and woven fiber bundles in X-ray computed tomography scanned carbon fiber reinforced polymer specimens

    Directory of Open Access Journals (Sweden)

    Johannes Weissenböck

    2016-11-01

    Full Text Available In recent years, advanced composite materials such as carbon fiber reinforced polymers (CFRP are used in many fields of application (e.g., automotive, aeronautic and leisure industry. These materials are characterized by their high stiffness and strength, while having low weight. Especially, woven carbon fiber reinforced materials have outstanding mechanical properties due to their fabric structure. To analyze and develop the fabrics, it is important to understand the course of the individual fiber bundles. Industrial 3D X-ray computed tomography (XCT as a nondestructive testing method allows resolving these individual fiber bundles. In this paper, we show our findings when applying the method of Bhattacharya et al. [6] for extracting fiber bundles on two new types of CFRP specimens. One specimen contains triaxial braided plies in an RTM6 resin and another specimen woven bi-diagonal layers. Furthermore, we show the required steps to separate the individual bundles and the calculation of the individual fiber bundles characteristics which are essential for the posterior visual analysis and exploration. We further demonstrate the classification of the individual fiber bundles within the fabrics to support the domain experts in perceiving the weaving structure of XCT scanned specimens.

  6. A Simple Birefringent Terahertz Waveguide Based on Polymer Elliptical Tube

    Science.gov (United States)

    Wang, Jing-Li; Yao, Jian-Quan; Chen, He-Ming; Li, Zhong-Yang

    2011-01-01

    We propose a simple birefringent terahertz (THz) waveguide which is a polymer elliptical tube with a cross section of elliptical ring structure. It can be achieved by stretching a normal circular-tube in one direction. Simulations based on the full-vector finite element method (FEM) show that this kind of waveguides exhibits high birefringence on a level of 10-2 over a wide THz frequency range. Moreover, as a majority of modal power is trapped in the air core inside the polymer elliptical tube, the THz waveguide guiding loss caused by material absorption can be reduced effectively.

  7. Potential polymer concrete heat exchanger tubes for corrosive environments

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, J.J.; Reams, W.; Cheng, H.C.

    1986-11-01

    It has long been known that carbon steel exposed to some geothermal brines is aggressively attacked, and large corrosion allowances must be made in the design of piping used in such environments. In addition, scaling of the pipes reduces the flow through within a short period of time. Several high temperature polymer concretes have been developed which can be used as non-corrosive liner materials. In addition, polymer concretes with high thermal conductivities have been developed which may be used as heat exchanger tubes for geothermal brines. Studies have indicated that polymer concretes will not scale as rapidly as carbon steel does, thus making them attractive alternatives for heat exchanger tubes. Thin walled, thermally conductive polymer concrete tubes have been made that can withstand pressures >4.1 MPa at 150/sup 0/C without leaking. Continuing studies are being made to characterize these materials and evaluate them for heat exchanger applications.

  8. Dynamic nuclear polarization in thin polymer foils and tubes

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.

    1995-02-01

    First results of DNP at 2.5 T and below 0.3 K in thin polymer foils and tubes with the chemical composition (CX 2) n, [ X = 1H, 2D, 19F ], doped with TEMPO, are presented. Appreciable polarization of protons, deuterons, and 19F-nuclei were obtained. The samples can be handled at room temperature for several hours, and therefore they are suitable for new applications.

  9. Dynamic nuclear polarization in thin polymer foils and tubes

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, B. van den [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Bunyatova, E.I. [Joint Inst. for Nuclear Research, Dubna (Russian Federation); Hautle, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Konter, J.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Mango, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1995-03-01

    First results of DNP at 2.5 T and below 0.3 K in thin polymer foils and tubes with the chemical composition (CX{sub 2}){sub n}, [X={sup 1}H, {sup 2}D, {sup 19}F], doped with TEMPO, are presented. Appreciable polarizations of protons, deuterons, and {sup 19}F-nuclei were obtained. The samples can be handled at room temperature for several hours, and therefore they are suitable for new applications. ((orig.))

  10. Tibetan Braid

    Science.gov (United States)

    2002-01-01

    On October 13, 2000, the Expedition 3 crew of the International Space Station, high over Tibet, took this interesting photo of the Brahmaputra River. This mighty Asian river carves a narrow west-east valley between the Tibetan Plateau to the north and the Himalaya Mountains to the south, as it rushes eastward for more than 1500 km in southwestern China. This 15-km stretch is situated about 35 km south of the ancient Tibetan capital of Lhasa where the river flow becomes intricately braided as it works and reworks its way through extensive deposits of erosional material. This pattern is indicative of a combination heavy sediment discharge from tributaries and reduction of the river's flow from either a change in gradient or perhaps even climate conditions over the watershed. The light color of the deposits and the milky color of the water is attributed to presence of glacial 'flour,' the fine material created by erosion from glaciers. Besides erosion by water and ice, this scene also depicts features created by wind. Note the delicate field of dunes on the alluvial fan toward the right edge of the image. The riverbed here is at an elevation of over 3,500 m, and with the long west-east extent of this barren valley, strong, persistent westerly winds also move and shape these deposits. Photos such as this one bring immediate visual understanding and appreciation of natural processes in some of the most remote locations on Earth. Image ISS003-E-6632, was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  11. Standing wave tube electro active polymer wave energy converter

    Science.gov (United States)

    Jean, Philippe; Wattez, Ambroise; Ardoise, Guillaume; Melis, C.; Van Kessel, R.; Fourmon, A.; Barrabino, E.; Heemskerk, J.; Queau, J. P.

    2012-04-01

    Over the past 4 years SBM has developed a revolutionary Wave Energy Converter (WEC): the S3. Floating under the ocean surface, the S3 amplifies pressure waves similarly to a Ruben's tube. Only made of elastomers, the system is entirely flexible, environmentally friendly and silent. Thanks to a multimodal resonant behavior, the S3 is capable of efficiently harvesting wave energy from a wide range of wave periods, naturally smoothing the irregularities of ocean wave amplitudes and periods. In the S3 system, Electro Active Polymer (EAP) generators are distributed along an elastomeric tube over several wave lengths, they convert wave induced deformations directly into electricity. The output is high voltage multiphase Direct Current with low ripple. Unlike other conventional WECs, the S3 requires no maintenance of moving parts. The conception and operating principle will eventually lead to a reduction of both CAPEX and OPEX. By integrating EAP generators into a small scale S3, SBM achieved a world first: direct conversion of wave energy in electricity with a moored flexible submerged EAP WEC in a wave tank test. Through an extensive testing program on large scale EAP generators, SBM identified challenges in scaling up to a utility grid device. French Government supports the consortium consisting of SBM, IFREMER and ECN in their efforts to deploy a full scale prototype at the SEMREV test center in France at the horizon 2014-2015. SBM will be seeking strategic as well as financial partners to unleash the true potentials of the S3 Standing Wave Tube Electro Active Polymer WEC.

  12. Visual classification of braided and woven fiber bundles in X-ray computed tomography scanned carbon fiber reinforced polymer specimens

    OpenAIRE

    Weissenböck, Johannes; Bhattacharya, Arindam; Plank, Bernhard; Heinzl, Christoph; Kastner, Johann

    2016-01-01

    In recent years, advanced composite materials such as carbon fiber reinforced polymers (CFRP) are used in many fields of application (e.g., automotive, aeronautic and leisure industry). These materials are characterized by their high stiffness and strength, while having low weight. Especially, woven carbon fiber reinforced materials have outstanding mechanical properties due to their fabric structure. To analyze and develop the fabrics, it is important to understand the course of the individu...

  13. Dynamic neck development in a polymer tube under internal pressure loading

    DEFF Research Database (Denmark)

    Lindgreen, Britta; Tvergaard, Viggo; Needleman, Alan

    2008-01-01

    The initiation and growth of necks in polymer tubes subjected to rapidly increasing internal pressure is analyzed numerically. Plane strain conditions are assumed to prevail in the axial direction. The polymer is characterized by a finite strain elastic-viscoplastic constitutive relation and the ......The initiation and growth of necks in polymer tubes subjected to rapidly increasing internal pressure is analyzed numerically. Plane strain conditions are assumed to prevail in the axial direction. The polymer is characterized by a finite strain elastic-viscoplastic constitutive relation...... against further expansion of the tube. The rate dependence of the necking behavior gives noticeable differences in neck development for slow loading versus fast loading....

  14. Braiding with Majorana fermions

    Science.gov (United States)

    Kauffman, Louis H.; Lomonaco, Samuel J.

    2016-05-01

    This paper is an introduction to relationships between topology, quantum computing and the properties of fermions. In particular we study the remarkable unitary braid group representations associated with Majorana fermions.

  15. UVC fluencies for preventative treatment of pseudomonas aeruginosa contaminated polymer tubes

    DEFF Research Database (Denmark)

    Bak, Jimmy; Ladefoged, Søren D.; Begovic, Tanja

    2010-01-01

    .40-1.50) normally used for tubing in catheter production. Determining whether or not UVC light exposure can disinfect and maintain the intra-luminal number of colony forming units (CFUs) at an exceedingly low level and thus avoid the growth and establishment of biofilm is of interest. The use of UVC diodes......Exposing Pseudomonas aeruginosa biofilm grown on the inner surface of Teflon and silicone tubes to UVC light (265 nm) from light emitting diodes (LED) has previously been shown to substantially reduce biofilm growth. Smaller UVC fluencies were required to disinfect Teflon tubes compared to silicone...... tubes. Light propagation enhancement in tubes can be obtained if the refractive index of the intra-luminal saline solution is higher than that of the polymer. This condition is achieved by using Teflon tubes with a low refractive index (1.34) instead of the polymers with a high refractive index (1...

  16. UVC fluencies for preventative treatment of Pseudomonas aeruginosa contaminated polymer tubes

    DEFF Research Database (Denmark)

    Bak, Jimmy; Ladefoged, Søren D; Begovic, Tanja

    2010-01-01

    .40-1.50) normally used for tubing in catheter production. Determining whether or not UVC light exposure can disinfect and maintain the intra-luminal number of colony forming units (CFUs) at an exceedingly low level and thus avoid the growth and establishment of biofilm is of interest. The use of UVC diodes......Exposing Pseudomonas aeruginosa biofilm grown on the inner surface of Teflon and silicone tubes to UVC light (265 nm) from light emitting diodes (LED) has previously been shown to substantially reduce biofilm growth. Smaller UVC fluencies were required to disinfect Teflon tubes compared to silicone...... tubes. Light propagation enhancement in tubes can be obtained if the refractive index of the intra-luminal saline solution is higher than that of the polymer. This condition is achieved by using Teflon tubes with a low refractive index (1.34) instead of the polymers with a high refractive index (1...

  17. Bulge formation and necking in a polymer tube under dynamic expansion

    DEFF Research Database (Denmark)

    Lindgreen, Britta; Tvergaard, Viggo; Needleman, Alan

    2008-01-01

    Bulging and necking in long thin polymer tubes subjected to increasing internal pressure are analysed numerically. The polymer is characterized by a finite strain elastic-viscoplastic constitutive relation and the calculations are carried out using a dynamic finite element program. Two types...

  18. Fully biodegradable self-rolled polymer tubes: a candidate for tissue engineering scaffolds.

    Science.gov (United States)

    Zakharchenko, Svetlana; Sperling, Evgeni; Ionov, Leonid

    2011-06-13

    We report an approach for the fabrication of fully biodegradable self-rolled tubes based on patterned polysuccinimide/polycaprolactone bilayers. These polymers are biocompatible, biodegradable, produced industrially, and are already approved for biomedical purposes. Both polycaprolactone and polysuccinimide are hydrophobic and intrinsically water-insoluble. Polysuccinimide, however, hydrolyzes in physiological buffer environment yielding water-swellable polyaspartic acid that causes the rolling of the polymer bilayer and formation of tubes. We demonstrate the possibility to encapsulate yeast cells using self-rolled tubes.

  19. Prediction of polymer tube life for solar hot water systems: A model of antioxidant loss

    Energy Technology Data Exchange (ETDEWEB)

    Mittelman, Gur; Davidson, Jane H.; Mantell, Susan C.; Su, Yan [Department of Mechanical Engineering, University of Minnesota, 111 Church St., S.E. Minneapolis, MN 55455 (United States)

    2008-05-15

    The successful use of polymer components in solar hot water systems requires an understanding and method of predicting material degradation in water. The relevant degradation mechanism is oxidation. Degradation from oxidation can be delayed through the use of antioxidant additives. However, once the antioxidants have been depleted, oxidation of the polymer and subsequent loss of mechanical integrity occur rapidly. In this study, antioxidant loss from polymer tubes is modeled. Dimensional analysis and results of the model show the rate of antioxidant loss is controlled by diffusion through the polymer. The diffusion time scale is dictated by the tube wall thickness. Antioxidant concentration profiles and depletion rates are presented for three representative tube geometries and temperatures of 293 and 333 K. The time to deplete 90% of the antioxidant is on the order of 1000-10,000 h. (author)

  20. Organization of polymer chains onto long, single-wall carbon nano-tubes: effect of tube diameter and cooling method.

    Science.gov (United States)

    Kumar, Sunil; Pattanayek, Sudip K; Pereira, Gerald G

    2014-01-14

    We use molecular dynamics simulations to investigate the arrangement of polymer chains when absorbed onto a long, single-wall carbon nano-tube (SWCNT). We study the conformation and organization of the polymer chains on the SWCNT and their dependence on the tube's diameter and the rate of cooling. We use two types of cooling processes: direct quenching and gradual cooling. The radial density distribution function and bond orientational order parameter are used to characterize the polymer chain structure near the surface. In the direct cooling process, the beads of the polymer chain organize in lamella-like patterns on the surface of the SWCNT with the long axis of the lamella parallel to the axis of the SWCNT. In a stepwise, gradual cooling process, the polymer beads form a helical pattern on the surface of a relatively thick SWCNT, but form a lamella-like pattern on the surface of a very thin SWCNT. We develop a theoretical (free energy) model to explain this difference in pattern structures for the gradual cooling process and also provide a qualitative explanation for the pattern that forms from the direct cooling process.

  1. Properties of closed 3-braids and braid representations of links

    CERN Document Server

    Stoimenow, Alexander

    2017-01-01

    This book studies diverse aspects of braid representations via knots and links. Complete classification results are illustrated for several properties through Xu’s normal 3-braid form and the Hecke algebra representation theory of link polynomials developed by Jones. Topological link types are identified within closures of 3-braids which have a given Alexander or Jones polynomial. Further classifications of knots and links arising by the closure of 3-braids are given, and new results about 4-braids are part of the work. Written with knot theorists, topologists,and graduate students in mind, this book features the identification and analysis of effective techniques for diagrammatic examples with unexpected properties.

  2. On braid monodromy factorizations

    Energy Technology Data Exchange (ETDEWEB)

    Kharlamov, V M [Institut de Recherche Matematique Avanee Universite Louis Pasteur et CNRS 7 rue Rene Descartes (France); Kulikov, Vik S [Steklov Mathematical Institute, Russian Academy of Sciences (Russian Federation)

    2003-06-30

    We introduce and develop a language of semigroups over the braid groups to study the braid monodromy factorizations (bmf's) of plane algebraic curves and other related objects. As an application, we give a new proof of Orevkov's theorem on the realization of bmf's over a disc by algebraic curves and show that the complexity of such a realization cannot be bounded in terms of the types of factors of the bmf. We also prove that the type of a bmf distinguishes Hurwitz curves with singularities of inseparable type up to H-isotopy and J-holomorphic cuspidal curves in CP{sup 2} up to symplectic isotopy.

  3. Effect of drag-reducing polymers on Tubing Performance Curve (TPC) in vertical gas-liquid flows

    NARCIS (Netherlands)

    Shoeibi Omrani, P.; Veltin, J.; Turkenburg, D.H.

    2014-01-01

    This paper discusses the effect of drag reducing polymers on the Tubing Performance Curve (TPC) of vertical air-water flows at near atmospheric conditions. The effect of polymer concentration, liquid and gas flow rates on the pressure drop curve (Tubing Performance Curve) was investigated

  4. Thin liquid film in polymer tubing : dynamics and dewetting in partial wetting condition

    Science.gov (United States)

    Hayoun, Pascaline; Letailleur, Alban; Teisseire, Jérémie; Verneuil, Emilie; Lequeux, François; Barthel, Etienne

    2015-11-01

    Polymers such as PVC and Silicone are low cost materials widely used in industry to produce tubing for fluid transport. Most of these applications involve repeated, intermittent flow of liquids which can lead to unwanted contamination. This study aims at better understanding contamination mechanisms during intermittent flow in polymer tubing, and at elucidating the relation between flow, wetting and contamination. We experimentally and theoretically investigate, flow regimes as well as dewetting process at the triple line induced by gravity flow of a vertical liquid slug in a cylindrical geometry. Our results for Newtonian fluids evidence a succession of thick film formation, hydraulic jump creation in the thickness profile, oscillatory regime and destabilization leading to substrate contamination. In order to understand theoretically the flow, one crucial quantity to assess is the film thickness in the inside of the tube. Based on an absorption measurement method, we provide explanations for behaviors and flow regimes observed experimentally.

  5. Microscopic Theories of Diffusion, Tube Localization and Slow Relaxation in Polymer Nanocomposites

    Science.gov (United States)

    Schweizer, Kenneth

    2014-03-01

    Dynamics in polymer nanocomposites is rich and complex but poorly understood due to the presence of multiple length scales, excluded volume effects and other factors. We have developed new statistical mechanical theories at the level of forces for particle and polymer motion in flexible and rigid polymers. This talk presents an overview, including quantitative comparisons to simulations and experiments. First, by combining Brownian motion, polymer physics and mode coupling ideas, a self-consistent theory for the non-hydrodynamic diffusion of a spherical nanoparticle in melts has been constructed. Three competing mechanisms are predicted: sieving-like diffusion through unentangled regions, reptation-driven constraint release in entangled melts, and activated hopping through entanglement meshes. The controlling mechanism depends on particle size, tube diameter and entanglement density. The approach can also treat soft fillers, nonspherical particles, adsorption, solutions and networks. Second, a self-consistent microscopic theory for the slow dynamics of a needle fluid in a matrix of static spheres has been developed which exactly enforces inter-needle topological uncrossability and needle- sphere impenetrability constraints at the two-body level. The rich dependences of the effective tube diameter and anisotropic diffusion constants on filler-needle aspect ratio, polymer concentration and particle volume fraction has been established. Due to steric blocking of longitudinal motion by obstacles, a literal localization transition is predicted that is controlled by the particle to tube diameter ratio. For a restricted window of parameter space, needles are predicted to diffuse via a ``renormalized'' reptation dynamics where compression of the tube and suppression of longitudinal diffusivity enter in a manner that depends on all system variables. Generalization of the approach to treat mobile fillers, flexible chains and nonrandom microstructure is possible.

  6. Thermal diffusivity measurements on porous carbon fiber reinforced polymer tubes

    Science.gov (United States)

    Gruber, Jürgen; Gresslehner, Karl Heinz; Mayr, Günther; Hendorfer, Günther

    2017-02-01

    This work presents the application of methods for the determination of the thermal diffusivity well suited for flat bodies adapted to cylindrical bodies. Green's functions were used to get the temperature time history for small and large times, for the approach of intersecting these two straight lines. To verify the theoretical considerations noise free data are generated by finite element simulations. Furthermore effects of inhomogeneous excitation and the anisotropic heat conduction of carbon fiber reinforced polymers were taken into account in these numerical simulations. It could be shown that the intersection of the two straight lines is suitable for the determination of the thermal diffusivity, although the results have to be corrected depending on the ratio of the cylinders inner and outer radii. Inhomogeneous excitation affects the results of this approach as it lead to multidimensional heat flux. However, based on the numerical simulations a range of the azimuthal angle exists, where the thermal diffusivity is nearly independent of the angle. The method to determine the thermal diffusivity for curved geometries by the well suited Thermographic Signal Reconstruction method and taking into account deviations from the slab by a single correction factor has great advantages from an industrial point of view, just like an easy implementation into evaluation software and the Thermographic Signal Reconstruction methods rather short processing time.

  7. Braids and coverings selected topics

    CERN Document Server

    Hansen, Vagn Lundsgaard

    1989-01-01

    This book is based on a graduate course taught by the author at the University of Maryland, USA. The lecture notes have been revised and augmented by examples. The work falls into two strands. The first two chapters develop the elementary theory of Artin Braid groups both geometrically and via homotopy theory, and discuss the link between knot theory and the combinatorics of braid groups through Markov's Theorem. The final two chapters give a detailed investigation of polynomial covering maps, which may be viewed as a homomorphism of the fundamental group of the base space into the Artin braid

  8. Entangled polymer chain melts: orientation and deformation dependent tube confinement and interchain entanglement elasticity

    Energy Technology Data Exchange (ETDEWEB)

    Sussman, Daniel [University of Pennsylvania; Schweizer, Kenneth [University of Illinois

    2013-01-01

    The phenomenological reptation-tube model is based on a single chain perspective and was originally proposed to explain the remarkable viscoelastic properties of dense entangled polymer liquids. However, simulations over the last two decades have revealed a fundamental tension in the model: it assumes that bonded, single-chain backbone stresses are the sole polymer contribution to the slowly relaxing component of stress storage and elasticity, but mounting evidence suggests that at the local level of forces it is interchain contributions that dominate, as in simple liquids. Here we show that based on a chain model constructed at the level of self-consistently determined primitive paths, an explicit force-level treatment of the correlated intermolecular contributions to stress that arise from chain uncrossability can essentially quantitatively predict the entanglement plateau modulus associated with the soft rubbery response of polymer liquids. Analogies to transient localization and elasticity in glass-forming liquids are identified. Predictions for the effect of macroscopic deformation and anisotropic orientational order on the tube diameter are also made. Based on the interchain stress perspective the theory reproduces some aspects of the rheological response to shear and extensional deformations associated with the single chain tube model.

  9. Entangled polymer chain melts: Orientation and deformation dependent tube confinement and interchain entanglement elasticity

    Science.gov (United States)

    Sussman, Daniel M.; Schweizer, Kenneth S.

    2013-12-01

    The phenomenological reptation-tube model is based on a single chain perspective and was originally proposed to explain the remarkable viscoelastic properties of dense entangled polymer liquids. However, simulations over the last two decades have revealed a fundamental tension in the model: it assumes that bonded, single-chain backbone stresses are the sole polymer contribution to the slowly relaxing component of stress storage and elasticity, but mounting evidence suggests that at the local level of forces it is interchain contributions that dominate, as in simple liquids. Here we show that based on a chain model constructed at the level of self-consistently determined primitive paths, an explicit force-level treatment of the correlated intermolecular contributions to stress that arise from chain uncrossability can essentially quantitatively predict the entanglement plateau modulus associated with the soft rubbery response of polymer liquids. Analogies to transient localization and elasticity in glass-forming liquids are identified. Predictions for the effect of macroscopic deformation and anisotropic orientational order on the tube diameter are also made. Based on the interchain stress perspective the theory reproduces some aspects of the rheological response to shear and extensional deformations associated with the single chain tube model.

  10. Biodegradable and Multifunctional Polymer Micro-Tubes for Targeting Photothermal Therapy

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2014-07-01

    Full Text Available We describe an innovative form of polymer micro-tubes with diverse functions including biodegradation, magnetic manipulation, and photothermal effect that employs and activates photothermal therapy to target cancer cells. The micro-tube comprised soybean protein isolate, poly-l-glutamic acid, magnetite nanoparticles, plus gold nanoparticles. Through electrostatic force, these components, with opposite charges, formed pairs of layers in the pores of the template, various bilayers of soybean protein isolate and poly-l-glutamic acid served as the biodegradable building wall to each micro-tube. The layers of magnetite nanoparticle functionalized micro-tubes enabled the micro-tube manipulate to target the cancer cells by using an external magnetic field. The photo-thermal effect of the layer of gold nanoparticles on the outer surface of the micro-tubes, when under irradiation and when brought about by the near infrared radiation, elevated each sample’s temperature. In addition, and when under the exposure of the near infrared radiation, the elevated temperature of the suspension of the micro-tubes, likewise with a concentration of 0.2 mg/mL, and similarly with a power of 2 W and as well maintained for 10 min, elevated the temperature of the suspension beyond 42 °C. Such temperatures induced apoptosis of target cancer cells through the effect of photothermal therapy. The findings assert that structured micro-tubes have a promising application as a photothermal agent. From this assertion, the implications are that this multifunctional agent will significantly improve the methodology for cancer diagnosis and therapy.

  11. Cable Braid Electromagnetic Penetration Model.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry K. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Langston, William L. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Basilio, Lorena I. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Johnson, W. A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    The model for penetration of a wire braid is rigorously formulated. Integral formulas are developed from energy principles and reciprocity for both self and transfer immittances in terms of potentials for the fields. The detailed boundary value problem for the wire braid is also setup in a very efficient manner; the braid wires act as sources for the potentials in the form of a sequence of line multipoles with unknown coefficients that are determined by means of conditions arising from the wire surface boundary conditions. Approximations are introduced to relate the local properties of the braid wires to a simplified infinite periodic planar geometry. This is used in a simplified application of reciprocity to be able to treat nonuniform coaxial geometries including eccentric interior coaxial arrangements and an exterior ground plane.

  12. Development of advanced grid stiffened (AGS) fiber reinforced polymer (FRP) tube-encased concrete columns : [technical summary].

    Science.gov (United States)

    2013-03-01

    In recent years, the use of fi ber reinforced polymer (FRP) tube-encased concrete columns for new construction and rebuilding : of engineering structures has increased. The purpose in FRP tube-encased concrete columns is to replace the steel rebar by...

  13. In-tube moleculary imprinted polymer solid-phase microextraction for the selective determination of propranolol.

    Science.gov (United States)

    Mullett, W M; Martin, P; Pawliszyn, J

    2001-06-01

    A molecularly imprinted polymer (MIP) material was synthesized for use as an in-tube solid-phase microextraction (SPME) adsorbent. The inherent selectivity and chemical and physical robustness of the MIP material was demonstrated as an effective stationary-phase material for in-tube SPME. An automated and on-line MIP SPME extraction method was developed for propranolol determination in biological fluids. This simplified the sample preparation process and the chromatographic separation of several beta-blocker compounds. The method developed for propranolol showed improved selectivity in comparison to alternative in-tube stationary-phase materials, overcoming the limitations of existing SPME coating materials. Preconcentration of the sample by the MIP adsorbent increased the sensitivity, yielding a limit of detection of 0.32 microg/mL by UV detection. Excellent method reproducibility (RSD 500 injections) were observed over a fairly wide linear dynamic range (0.5-100 microg/mL) in serum samples. To our knowledge, this is the first report on the automated application of a MIP material for in-tube SPME. The method was inexpensive, simple to set up, and simplified the choice of SPME adsorbent for in-tube extraction. The approach can potentially be extended to other MIPs for the determination of a wide range of chemically significant analytes.

  14. Studies on transport phenomena in polymer solutions and suspensions flowing through tubes of tortuous wall geometry

    Science.gov (United States)

    Narayanan, C. M.

    2014-02-01

    Attempts have been made to analyse the momentum and heat transfer characteristics in tortuous flow of non-Newtonian fluids such as suspensions and polymer solutions through tubes of diverging-converging geometry. The results of the study indicate that the transfer coefficients are significantly higher in such systems as compared to the conventional couette flow (through uniform cylindrical tubes). Moreover, the simultaneous increase in pressure drop due to the tortuous wall geometry has been observed to be relatively insignificant. Fluids with different rheological characteristics such as Bingham plastic fluids, pseudoplastic fluids, Ellis model fluids and fluids obeying Reiner-Philippoff rheology have been studied. The specific advantages of these geometries in providing enhanced performance efficiency have been effectively highlighted.

  15. Design Tools and Workflows for Braided Structures

    DEFF Research Database (Denmark)

    Vestartas, Petras; Heinrich, Mary Katherine; Zwierzycki, Mateusz

    2017-01-01

    This paper presents design workflows for the representation, analysis and fabrication of braided structures. The workflows employ a braid pattern and simulation method which extends the state-of-the-art in the following ways: by supporting the braid design of both pre-determined target shapes...... and exploratory, generative, or evolved designs; by incorporating material and fabrication constraints generalised for both hand and machine; by providing a greater degree of design agency and supporting real-time modification of braid topologies. The paper first introduces braid as a technique, stating...... the objectives and motivation for our exploration of braid within an architectural context and highlighting both the relevance of braid and current lack of suitable design modelling tools to support our approach. We briefly introduce the state-of-the-art in braid representation and present the characteristics...

  16. The antimicrobial effect of Octenidine-dihydrochloride coated polymer tracheotomy tubes on Staphylococcus aureus and Pseudomonas aeruginosa colonisation

    Science.gov (United States)

    2009-01-01

    Background The surface of polymeric tracheotomy tubes is a favourable environment for biofilm formation and therefore represents a potential risk factor for the development of pneumonia after tracheotomy. The aim of this in-vitro study was to develop octenidine-dihydrochloride (OCT) coated polymer tracheotomy tubes and investigate any effects on Staphylococcus (S.) aureus and Pseudomonas (P.) aeruginosa colonization. Additionally the resistance of the OCT coating was tested using reprocessing procedures like brushing, rinsing and disinfection with glutaraldehyde Results Contamination with S. aureus: Before any reprocessing, OCT coated tracheotomy tubes were colonized with 103 cfu/ml and uncoated tracheotomy tubes with 105 cfu/ml (P = 0.045). After reprocessing, no differences in bacterial concentration between modified and conventional tubes were observed. Contamination with P. aeruginosa: Before reprocessing, OCT coated tubes were colonized with 106 cfu/ml and uncoated tubes with 107 cfu/ml (P = 0.006). After reprocessing, no significant differences were observed. Conclusion OCT coating initially inhibits S. aureus and P. aeruginosa colonisation on tracheotomy tubes. This effect, however, vanishes quickly after reprocessing of the tubes due to poor adhesive properties of the antimicrobial compound. Despite the known antimicrobial effect of OCT, its use for antimicrobial coating of tracheotomy tubes is limited unless methods are developed to allow sustained attachment to the tube. PMID:19630994

  17. The antimicrobial effect of Octenidine-dihydrochloride coated polymer tracheotomy tubes on Staphylococcus aureus and Pseudomonas aeruginosa colonisation

    Directory of Open Access Journals (Sweden)

    Leonhard Matthias

    2009-07-01

    Full Text Available Abstract Background The surface of polymeric tracheotomy tubes is a favourable environment for biofilm formation and therefore represents a potential risk factor for the development of pneumonia after tracheotomy. The aim of this in-vitro study was to develop octenidine-dihydrochloride (OCT coated polymer tracheotomy tubes and investigate any effects on Staphylococcus (S. aureus and Pseudomonas (P. aeruginosa colonization. Additionally the resistance of the OCT coating was tested using reprocessing procedures like brushing, rinsing and disinfection with glutaraldehyde Results Contamination with S. aureus: Before any reprocessing, OCT coated tracheotomy tubes were colonized with 103 cfu/ml and uncoated tracheotomy tubes with 105 cfu/ml (P = 0.045. After reprocessing, no differences in bacterial concentration between modified and conventional tubes were observed. Contamination with P. aeruginosa: Before reprocessing, OCT coated tubes were colonized with 106 cfu/ml and uncoated tubes with 107 cfu/ml (P = 0.006. After reprocessing, no significant differences were observed. Conclusion OCT coating initially inhibits S. aureus and P. aeruginosa colonisation on tracheotomy tubes. This effect, however, vanishes quickly after reprocessing of the tubes due to poor adhesive properties of the antimicrobial compound. Despite the known antimicrobial effect of OCT, its use for antimicrobial coating of tracheotomy tubes is limited unless methods are developed to allow sustained attachment to the tube.

  18. Experimental Study of Concrete-filled Carbon Fiber Reinforced Polymer Tube with Internal Reinforcement under Axially Loading

    OpenAIRE

    SUN Wenbin; Qiangqiang ZHU; Weizhong HE

    2014-01-01

    Comparing with the circular concrete columns confined with fiber reinforced polymer (FRP) wrap or tube, the rectilinear confined columns were reported much less. Due to the non-uniform distribution of confining pressure in the rectilinear confined columns, the FRP confinement effectiveness was significant reduced. This paper presents findings of an experimental program where nine prefabricated rectangular cross-section CFRP tubes with CFRP integrated crossties filled concrete to form concrete...

  19. Fallopian tube occlusion with a shape memory polymer device: evaluation in a rabbit model.

    Science.gov (United States)

    Tang, Shuai; Zhang, Chan-Yu; Huang, Mei-Na; Luo, Yan-Feng; Liang, Zhi-Qing

    2013-02-01

    The present study evaluates the feasibility of a shape memory polymer (SMP) device for fallopian tube occlusion in rabbits. The SMP contraceptive device is made of poly(dl-lactic acid)-based poly(urethane urea) SMP in the shape of a spiral cylinder that was 10 mm long and had a diameter of 2.6 mm. Using this device, bilateral transuterine fallopian tube occlusions were performed in 78 New Zealand white female rabbits. Forty-eight female rabbits (group 1) were chosen as the experimental group and were implanted with the SMP devices. The remaining 30 female rabbits (group 2) served as the control group, which only received an incision in the abdomen but no SMP device. Follow-up consisted of hysterosalpingography, histologic evaluation and contraceptive effect. In addition, the shape memory behavior and in vivo degradation characterization of the SMP device were observed in this study. Under heat (37 °C) stimulation, the temporary shape SMP device returned to its permanent shape within 60 s. The average weight loss percentage of SMP devices was 7.0% at 2 weeks and 72.5% at 12 weeks. The inflammatory reactions caused by SMP devices were aseptic and nonspecific at 2 and 12 weeks, respectively. The SMP device boundaries and the surrounding tissues were obscured by fiber hyperplasia in 11/12 tubes at 24 weeks. Hysterosalpingography showed an occluded fallopian tube of Group 1 in 6/6 rabbits at 12 weeks and 6/6 rabbits at 24 weeks. No pregnancy was found in all 18 rabbits of group 1 (contraceptive rate of 100%); all 20 rabbits in the control group were pregnant. Biodegradable and biocompatible SMP devices could provide reliable, instant and permanent tubal occlusion. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Braid foliations in low-dimensional topology

    CERN Document Server

    LaFountain, Douglas J

    2017-01-01

    This book is a self-contained introduction to braid foliation techniques, which is a theory developed to study knots, links and surfaces in general 3-manifolds and more specifically in contact 3-manifolds. With style and content accessible to beginning students interested in geometric topology, each chapter centers around a key theorem or theorems. The particular braid foliation techniques needed to prove these theorems are introduced in parallel, so that the reader has an immediate "take-home" for the techniques involved. The reader will learn that braid foliations provide a flexible toolbox capable of proving classical results such as Markov's theorem for closed braids and the transverse Markov theorem for transverse links, as well as recent results such as the generalized Jones conjecture for closed braids and the Legendrian grid number conjecture for Legendrian links. Connections are also made between the Dehornoy ordering of the braid groups and braid foliations on surfaces. All of this is accomplished w...

  1. Performance evaluation of cross-flow single-phase liquid-to-gas polymer tube heat exchanger

    Science.gov (United States)

    Dewanjee, Sujan; Hossain, Md. Rakibul; Rahman, Md. Ashiqur

    2017-06-01

    Reduced core weight and material cost, higher corrosion resistance are some of the major eye catching properties to study polymers over metal in heat exchanger applications in spite of the former's relatively low thermal conductivity and low strength. In the present study, performance of polymer parallel thin tube heat exchanger is numerically evaluated for cross flow liquid to air applications for a wide range of design and operating parameters such as tube diameter, thickness, fluid velocity and temperature, etc. using Computational Fluid Dynamics (CFD). Among a range of available polymeric materials, those with a moderate to high thermal conductivity and strength are selected for this study. A 90 cm × 1 cm single unit of polymer tubes, with appropriate number of tubes such that at least a gap of 5 mm is maintained in between the tubes, is used as a basic unit and multiple combination in the transverse direction of this single unit is simulated to measure the effect. The tube inner diameter is varied from 2 mm to 4 mm and the pressure drop is measured to have a relative idea of pumping cost. For each inner diameter the thickness is varied from .5 mm to 2.5 mm. The water velocity and the air velocity are varied from 0.4 m/s to 2 m/s and 1 m/s to 5 m/s, respectively. The performance of the polymer heat exchanger is compared with that of metal heat exchanger through and an optimum design for polymer heat exchanger is sought out.

  2. Closed loop control of a cylindrical tube type Ionic Polymer Metal Composite (IPMC)

    Science.gov (United States)

    Mead, Benjamin T.

    The goal of this research is to provide a framework for the integration of tube type, cylindrical Ionic Polymer Metal-Composite (IPMC) into conventional devices. IPMCs are one of the most widely used types of electro-active polymer actuator, due to their low electric driving potential and large deformation range. For this research a tube type IPMC was investigated. This IPMC has a circular cross section with four separate electrodes on its surface and a hole through the middle. The four electrodes allow for biaxial bending and accurate control of the tip location. One of the main advantages of using this type of IPMC is the ability to embed a specific tool and accurately control the tool tip location using the large deflection range of the IPMC. This ability has widespread applications including in the biomedical field for use in active catheter procedures. First, this relatively new type of IPMC is investigated and characterized. The processes and materials used are described and the functional design is explored. Before the modeling process beings the basic functions of the IPMC are investigated. To this end force and displacement experiments are performed to describe the activation of the tube type IPMC. This data will be used later to verify and calibrate the mathematical simulations. Second, a three dimensional multi-physics finite element model is developed using COMSOL 4.3a. This model will automatically couple three physics packages and provide a description of the fluid interactions within the tube type IPMC. This model is then compared against the experimental displacement results to calibrate the simulation. Using this simulation design parameters are declared including, overall diameter, and tool hole size. The performance of the IPMC is then simulated while varying these parameters. Third, an electro-mechanical model of the IPMC is developed. This macroscopic model is used to relate the input voltage to an associated tip deflection. Several model types

  3. Quantifying chain reptation in entangled polymer melts: topological and dynamical mapping of atomistic simulation results onto the tube model.

    Science.gov (United States)

    Stephanou, Pavlos S; Baig, Chunggi; Tsolou, Georgia; Mavrantzas, Vlasis G; Kröger, Martin

    2010-03-28

    The topological state of entangled polymers has been analyzed recently in terms of primitive paths which allowed obtaining reliable predictions of the static (statistical) properties of the underlying entanglement network for a number of polymer melts. Through a systematic methodology that first maps atomistic molecular dynamics (MD) trajectories onto time trajectories of primitive chains and then documents primitive chain motion in terms of a curvilinear diffusion in a tubelike region around the coarse-grained chain contour, we are extending these static approaches here even further by computing the most fundamental function of the reptation theory, namely, the probability psi(s,t) that a segment s of the primitive chain remains inside the initial tube after time t, accounting directly for contour length fluctuations and constraint release. The effective diameter of the tube is independently evaluated by observing tube constraints either on atomistic displacements or on the displacement of primitive chain segments orthogonal to the initial primitive path. Having computed the tube diameter, the tube itself around each primitive path is constructed by visiting each entanglement strand along the primitive path one after the other and approximating it by the space of a small cylinder having the same axis as the entanglement strand itself and a diameter equal to the estimated effective tube diameter. Reptation of the primitive chain longitudinally inside the effective constraining tube as well as local transverse fluctuations of the chain driven mainly from constraint release and regeneration mechanisms are evident in the simulation results; the latter causes parts of the chains to venture outside their average tube surface for certain periods of time. The computed psi(s,t) curves account directly for both of these phenomena, as well as for contour length fluctuations, since all of them are automatically captured in the atomistic simulations. Linear viscoelastic

  4. Development of braided drug-loaded nanofiber sutures

    Energy Technology Data Exchange (ETDEWEB)

    Hu Wen [School of Materials Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Huang Zhengming [School of Aerospace Engineering and Applied Mechanics, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Liu Xiangyang, E-mail: huangzm@tongji.edu.cn [Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 (Singapore)

    2010-08-06

    The objectives of this work are twofold. Firstly, while most work on electrospinning is limited to the development of only functional materials, a structural application of electrospun nanofibers is explored. Secondly, a drug-loaded tissue suture is fabricated and its various properties are characterized. Braided drug-loaded nanofiber sutures are obtained by combining an electrospinning process with a braiding technique followed by a coating procedure. Two different electrospinning techniques, i.e. blend and coaxial electrospinning, to incorporate a model drug cefotaxime sodium (CFX-Na) into poly(L-lactic acid) (PLLA) nanofibers have been applied and compared with each other. Properties of the braided drug-loaded sutures are characterized through a variety of methods including SEM, TEM and tensile testing. The results show that the nanofibers had a preferable micromorphology. The drug was incorporated into the polymer nanofibers homogeneously, with no cross-linking. The nanofibers maintained their fibrous structures. An in vitro release study indicates that the drug-loaded nanofibers fabricated by blend electrospinning and coaxial electrospinning had a different drug release behavior. An inhibition zone experiment shows that both sutures obtained from the nanofibers of the different electrospinning techniques had favorable antibacterial properties. The drug-loaded sutures had preferable histological compatibility performance compared with commercial silk sutures in an in vivo comparative study.

  5. A yarn interaction model for circular braiding

    NARCIS (Netherlands)

    van Ravenhorst, J.H.; Akkerman, Remko

    2016-01-01

    Machine control data for the automation of the circular braiding process has been generated using previously published mathematical models that neglect yarn interaction. This resulted in a significant deviation from the required braid angle at mandrel cross-sectional changes, likely caused by an

  6. Emergent Braided Matter of Quantum Geometry

    Directory of Open Access Journals (Sweden)

    Sundance Bilson-Thompson

    2012-03-01

    Full Text Available We review and present a few new results of the program of emergent matter as braid excitations of quantum geometry that is represented by braided ribbon networks. These networks are a generalisation of the spin networks proposed by Penrose and those in models of background independent quantum gravity theories, such as Loop Quantum Gravity and Spin Foam models. This program has been developed in two parallel but complimentary schemes, namely the trivalent and tetravalent schemes. The former studies the braids on trivalent braided ribbon networks, while the latter investigates the braids on tetravalent braided ribbon networks. Both schemes have been fruitful. The trivalent scheme has been quite successful at establishing a correspondence between braids and Standard Model particles, whereas the tetravalent scheme has naturally substantiated a rich, dynamical theory of interactions and propagation of braids, which is ruled by topological conservation laws. Some recent advances in the program indicate that the two schemes may converge to yield a fundamental theory of matter in quantum spacetime.

  7. Evaluation of Ultrasonic and Thermal Nondestructive Evaluation for the Characterization of Aging Degradation in Braided Composite Materials

    Science.gov (United States)

    Martin, Richard E.

    2010-01-01

    This paper examines the ability of traditional nondestructive evaluation (NDE) techniques to measure the degradation of braided polymer composite materials subjected to thermal-humidity cycling to simulate aging. A series of braided composite coupons were examined using immersion ultrasonic and pulsed thermography techniques in the as received condition. These same specimens were then examined following extended thermal-humidity cycling. Results of this examination did not show a significant change in the resulting (NDE) signals.

  8. Design Tools and Workflows for Braided Structures

    DEFF Research Database (Denmark)

    Vestartas, Petras; Heinrich, Mary Katherine; Zwierzycki, Mateusz

    2017-01-01

    and merits of our method, demonstrated though four example design and analysis workflows. The workflows frame specific aspects of enquiry for the ongoing research project flora robotica. These include modelling target geometries, automatically producing instructions for fabrication, conducting structural......This paper presents design workflows for the representation, analysis and fabrication of braided structures. The workflows employ a braid pattern and simulation method which extends the state-of-the-art in the following ways: by supporting the braid design of both pre-determined target shapes...... and exploratory, generative, or evolved designs; by incorporating material and fabrication constraints generalised for both hand and machine; by providing a greater degree of design agency and supporting real-time modification of braid topologies. The paper first introduces braid as a technique, stating...

  9. Experimental investigation of braided fabric forming

    Science.gov (United States)

    Wang, Peng; Soulat, Damien; Legrand, Xavier; Zemni, Lilia; Jacquot, Pierre-Baptiste

    2016-10-01

    Woven and braided textile structures are largely used as the composite reinforcements. Forming of the continuous fibre reinforcements and thermoplastic resin commingled yarns can be performed at room temperature. The "cool" forming stage is well-controlled and more economical compared to thermoforming. Many studies have been addressed for carbon and glass fibres / thermoplastic commingled yarns reinforced composite forming for woven structure. On the contrary, few research works has deal with the natural fibre reinforced textile forming and none concerns the braided fabrics forming. In this present work, the Flax/Polyamide 12 commingled yarns are used to produce braided fabric and then to analyze their deformability behaviour.

  10. Modeling of Failure for Analysis of Triaxial Braided Carbon Fiber Composites

    Science.gov (United States)

    Goldberg, Robert K.; Littell, Justin D.; Binienda, Wieslaw K.

    2010-01-01

    In the development of advanced aircraft-engine fan cases and containment systems, composite materials are beginning to be used due to their low weight and high strength. The design of these structures must include the capability of withstanding impact loads from a released fan blade. Relatively complex triaxially braided fiber architectures have been found to yield the best performance for the fan cases. To properly work with and design these structures, robust analytical tools are required that can be used in the design process. A new analytical approach models triaxially braided carbon fiber composite materials within the environment of a transient dynamic finite-element code, specifically the commercially available transient dynamic finite-element code LS-DYNA. The geometry of the braided composites is approximated by a series of parallel laminated composites. The composite is modeled by using shell finite elements. The material property data are computed by examining test data from static tests on braided composites, where optical strain measurement techniques are used to examine the local strain variations within the material. These local strain data from the braided composite tests are used along with a judicious application of composite micromechanics- based methods to compute the stiffness properties of an equivalent unidirectional laminated composite required for the shell elements. The local strain data from the braided composite tests are also applied to back out strength and failure properties of the equivalent unidirectional composite. The properties utilized are geared towards the application of a continuum damage mechanics-based composite constitutive model available within LS-DYNA. The developed model can be applied to conduct impact simulations of structures composed of triaxially braided composites. The advantage of this technology is that it facilitates the analysis of the deformation and damage response of a triaxially braided polymer matrix

  11. Diagrammatics of braided group gauge theory

    CERN Document Server

    Majid, S

    1996-01-01

    We develop a gauge theory or theory of bundles and connections on them at the level of braids and tangles. Extending recent algebraic work, we provide now a fully diagrammatic treatment of principal bundles, a theory of global gauge transformations, associated braided fiber bundles and covariant derivatives on them. We describe the local structure for a concrete Z_3-graded or `anyonic' realization of the theory.

  12. Experimental Study of Concrete-filled Carbon Fiber Reinforced Polymer Tube with Internal Reinforcement under Axially Loading

    Directory of Open Access Journals (Sweden)

    Wenbin SUN

    2014-12-01

    Full Text Available Comparing with the circular concrete columns confined with fiber reinforced polymer (FRP wrap or tube, the rectilinear confined columns were reported much less. Due to the non-uniform distribution of confining pressure in the rectilinear confined columns, the FRP confinement effectiveness was significant reduced. This paper presents findings of an experimental program where nine prefabricated rectangular cross-section CFRP tubes with CFRP integrated crossties filled concrete to form concrete-filled FRP tube (CFFT short columns and three plain concrete control specimens were tested. All specimens were axially loaded until failure. The rest results showed that the stress-strain curves of CFFTs consisted of two distinct branches, an ascending branch before the concrete peak stress was reaches and a second branch that terminated when the tube ruptured, and that the CFFTs with integrated crossties experienced most uniform confinement pressure distribution. Test research also found that the stress-strain curves of CFFTs indicated an increase in ductility. These demonstrate that this confinement system can produce higher lateral confinement stiffness. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6035

  13. Elementary damping properties in braided composite materials

    Science.gov (United States)

    Dion, Bernard L.; Sadler, Robert; Silverberg, Larry

    1994-05-01

    This paper investigates the damping level trends of three-dimensionally braided composites as a function of matrix material, fiber-matrix interface, fiber braid angle, fiber volume, and axial fiber tow size. With knowledge of such trends, designers may increase the structural damping in a 3-D braided composite component, thereby reducing component vibration, shock response, and fatigue. The logarithmic decrements of the fundamental mode response of cantilevered, 3-D braided composite beam specimens were calculated for comparison. Although the logarithmic decrements of two specimens, differing only in their matrix materials (Tactix 123 and Epon 828), were essentially identical, both were considerably larger than that for steel. The value for the decrement of these two composite specimens' response was taken as a reference. Altering the nature of the fiber-matrix interface by lubricating the fibers before specimen consolidation greatly increased the damping relative to the baseline. Trends of increasing damping were measured with both increasing fiber braid angle and fiber volume. Finally, increasing levels of damping are reported for decreases in axial fiber tow size. Explanations for these trends, based on the possible microscopic and macroscopic nature of the braided composites, are offered.

  14. Interchain tube pressure effect in the flow dynamics of bi-disperse polymer melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.

    2015-01-01

    The constitutive equation as reported by Rasmussen and Huang (Rheologica Acta 53:199–208, 2014b), explaining the flow dynamics of oligomer (containing a least two Kuhn step)-diluted narrow molecular weight-distributed polymers were extended to general bi-disperse polymer melt system. It was assumed...... that the Rouse time of a particular polymer chain is dependent on the total number of Kuhn steps of the polymers in direct contact with the considered polymer chain. This number of Kuhn steps is proportional to the weight average molecular weight, M w , replacing the involved molecular weight in the equation......:453–476, 2006) and polyisoprene systems as reported by Read et al. (J Rheol 56:823–873, 2012) were within quantitatively agreement with the derived model. This included both startup of extension as well as shear flow. One exception was observed. In the most diluted polyisoprene blend, the measured extensional...

  15. Probability and braiding statistics in Majorana nanowires

    Science.gov (United States)

    Clarke, David J.; Sau, Jay D.; Das Sarma, S.

    2017-04-01

    Given recent progress in the realization of Majorana zero modes in semiconducting nanowires with proximity-induced superconductivity, a crucial next step is to attempt an experimental demonstration of the predicted braiding statistics associated with the Majorana mode. Such a demonstration should, in principle, confirm that the experimentally observed zero-bias anomalies are indeed due to the presence of anyonic Majorana zero modes. Moreover, such a demonstration would be a breakthrough at the level of fundamental physics: the first clear demonstration of a non-Abelian excitation. It is therefore important to clarify the expected signals of Majorana physics in the braiding context and to differentiate these signals from those that might also arise in nontopological variants of the same system. A definitive and critical distinction between signals expected in topological (i.e., anyonic) and nontopological (i.e., trivial) situations is therefore essential for future progress in the field. In this paper, we carefully examine the expected signals of proposed braiding and fusion experiments in topological and nontopological variants of the experimental nanowire systems in which Majoranas are predicted to occur. We point out situations where `trivial' and `anyonic' signatures may be qualitatively similar experimentally, necessitating a certain level of caution in the interpretation of various proposed fusion and braiding experiments. We find in particular that braiding experiments consisting of full braids (two Majorana exchanges) are better at distinguishing between topological and nontopological systems than fusion experiments or experiments with an odd number of Majorana exchanges. Successful fusion experiments, particularly in nanowires where zero bias conductance peaks are also observed, can also provide strong evidence for the existence of Majorana modes, but such fusion evidence without a corresponding braiding success is not definitive.

  16. Investigating the Inter-Tube Conduction Mechanism in Polycarbonate Nanocomposites Prepared with Conductive Polymer-Coated Carbon Nanotubes

    KAUST Repository

    Ventura, Isaac Aguilar

    2015-12-16

    A well-known strategy to improve the electrical conductivity of polymers is to dope them with high-aspect-ratio and conductive nanoparticles such as carbon nanotubes (CNTs). However, these nanocomposites also exhibit undesirable properties such as damage-sensitive and history-dependent conductivity because their macroscopic electrical conductivity is largely determined by the tunneling effect at the tube/tube interface. To reduce these issues, new nanocomposites have been developed with CNTs that have been coated with a conductive layer of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS). It has been posited that the insulating region between the CNTs is replaced by a conductive polymer bridge; this has not been proven up to now. We propose here to investigate in-depth how the macroscopic conductivity of these materials is changing when (1) varying the frequency of the electrical loading (impedance spectroscopy), (2) varying the mechanical hydrostatic pressure, and (3) varying the voltage of the electrical loading. The response is systematically compared to the one of conventional carbon nanotube/polycarbonate (CNT/PC) nanocomposites so we can clarify how efficiently the tunneling effect is suppressed from these composites. The objective is to elucidate further the mechanism for conduction in such material formulations.

  17. Equilibrium theory for braided elastic filaments

    Science.gov (United States)

    van der Heijden, Gert

    Motivated by supercoiling of DNA and other filamentous structures, we formulate a theory for equilibria of 2-braids, i.e., structures formed by two elastic rods winding around each other in continuous contact and subject to a local interstrand interaction. Unlike in previous work no assumption is made on the shape of the contact curve. Rather, this shape is found as part of the solution. The theory is developed in terms of a moving frame of directors attached to one of the strands with one of the directors pointing to the position of the other strand. The constant-distance constraint is automatically satisfied by the introduction of what we call braid strains. The price we pay is that the potential energy involves arclength derivatives of these strains, thus giving rise to a second-order variational problem. The Euler-Lagrange equations for this problem give balance equations for the overall braid force and moment referred to the moving frame as well as differential equations that can be interpreted as effective constitutive relations encoding the effect that the second strand has on the first as the braid deforms under the action of end loads. Simple analytical cases are discussed first and used as starting solutions in parameter continuation studies to compute classes of both open and closed (linked or knotted) braid solutions.

  18. Development of advanced grid stiffened (AGS) fiber reinforced polymer (FRP) tube-encased concrete columns.

    Science.gov (United States)

    2013-03-01

    In this project, a new type of confining device, a latticework of interlacing fiber reinforced polymer (FRP) ribs that are jacketed by a FRP skin, is proposed, manufactured, tested, and modeled to encase concrete cylinders. This systematic study incl...

  19. Do Membranes Dream of Electric Tubes? Advanced Membranes Using Carbon Nanotube - Polymer Nanocomposites

    Science.gov (United States)

    de Lannoy, Charles-Francois Pedro Claude Karolek Ghislain

    Membrane technologies represent an energy efficient, effective solution for treating municipal and commercial waters/wastewaters. Membranes are predominantly polymer-based and despite steady advances in polymeric materials, they continue to suffer from operational problems including biofouling and breakages. This work addresses these two disparate problems by developing novel CNT-polymer nanocomposite materials that contain variously functionalized carbon nanotubes (fCNTs) in low quantities (surface hydrophilicity, fine control over molecular weight cut-off and flux, and surface electrical conductivity. Membranes with high surface electrical conductivity were further tested for their anti-biofouling properties. Finally, CNT stability and polymer compatibility were evaluated throughout membrane manufacture, use, and cleaning. The incorporation of CNTs mixed in bulk phase and linked through ionic associations in polymer matrices showed significant (50%) increases in Young's modulus for certain CNT functionalizations and derivatization percent. Membranes formed with high surface electrical conductivity demonstrated almost complete resistance to biofouling (> 95%) in long-term bacterially challenged experiments. CNTs and polymer mixtures that lacked covalent or ionic bonds were susceptible to significant (up to 10%) loss of CNTs during membrane non-solvent gelation and aggressive chemical cleaning treatment. Functionalized carbon nanotubes endow polymer membranes with their unique strength and electrically conductive properties. These added properties were demonstrated to greatly improve membrane operational efficiency and membrane longevity. CNT-polymer nanocomposite membranes offer low-energy, high-efficiency, and long-lifetime alternatives to traditional polymer membranes. With further advances in polymeric nanomaterials, membrane technology has the potential for wide applicability across many fields outside of water filtration and desalination.

  20. A UVC Device for Intra-luminal Disinfection of Catheters: In Vitro Tests on Soft Polymer Tubes Contaminated with Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Candida albicans

    DEFF Research Database (Denmark)

    Bak, Jimmy; Begovic, Tanja; Bjarnsholt, Thomas

    2011-01-01

    Bacterial colonization of central venous catheters (CVCs) causes severe complications in patients. As a result, developing methods to remove and prevent bacterial and fungal colonization of CVCs is imperative. Recently, we have demonstrated that disinfection by radiation of polymer tubes with UVC...... light is possible. In this paper we present dose-response results using a newly developed UVC disinfection device, which can be connected to a Luer catheter hub. The device was tested on soft polymer tubes contaminated with a pallet of microorganisms, including Candida albicans, Staphylococcus aureus......, Escherichia coli and Pseudomonas aeruginosa (ca 10(3) CFU mL(-1) ). The tubes were equipped with a modified catheter hub and interfaced to the disinfection device via a middle piece separating the disinfection device from the hub. The contamination lasted for 3 h prior to treatment to simulate an aseptic...

  1. Unit cell geometry of 3-D braided structures

    Science.gov (United States)

    Du, Guang-Wu; Ko, Frank K.

    1993-01-01

    The traditional approach used in modeling of composites reinforced by three-dimensional (3-D) braids is to assume a simple unit cell geometry of a 3-D braided structure with known fiber volume fraction and orientation. In this article, we first examine 3-D braiding methods in the light of braid structures, followed by the development of geometric models for 3-D braids using a unit cell approach. The unit cell geometry of 3-D braids is identified and the relationship of structural parameters such as yarn orientation angle and fiber volume fraction with the key processing parameters established. The limiting geometry has been computed by establishing the point at which yarns jam against each other. Using this factor makes it possible to identify the complete range of allowable geometric arrangements for 3-D braided preforms. This identified unit cell geometry can be translated to mechanical models which relate the geometrical properties of fabric preforms to the mechanical responses of composite systems.

  2. Braid group representation on quantum computation

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Ryan Kasyfil, E-mail: kasyfilryan@gmail.com [Department of Computational Sciences, Bandung Institute of Technology (Indonesia); Muchtadi-Alamsyah, Intan, E-mail: ntan@math.itb.ac.id [Algebra Research Group, Bandung Institute of Technology (Indonesia)

    2015-09-30

    There are many studies about topological representation of quantum computation recently. One of diagram representation of quantum computation is by using ZX-Calculus. In this paper we will make a diagrammatical scheme of Dense Coding. We also proved that ZX-Calculus diagram of maximally entangle state satisfies Yang-Baxter Equation and therefore, we can construct a Braid Group representation of set of maximally entangle state.

  3. Electrostatic braiding and homologous pairing of DNA double helices.

    Science.gov (United States)

    Cortini, Ruggero; Kornyshev, Alexei A; Lee, Dominic J; Leikin, Sergey

    2011-08-17

    Homologous pairing and braiding (supercoiling) have crucial effects on genome organization, maintenance, and evolution. Generally, the pairing and braiding processes are discussed in different contexts, independently of each other. However, analysis of electrostatic interactions between DNA double helices suggests that in some situations these processes may be related. Here we present a theory of DNA braiding that accounts for the elastic energy of DNA double helices as well as for the chiral nature of the discrete helical patterns of DNA charges. This theory shows that DNA braiding may be affected, stabilized, or even driven by chiral electrostatic interactions. For example, electrostatically driven braiding may explain the surprising recent observation of stable pairing of homologous double-stranded DNA in solutions containing only monovalent salt. Electrostatic stabilization of left-handed braids may stand behind the chiral selectivity of type II topoisomerases and positive plasmid supercoiling in hyperthermophilic bacteria and archea. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. Preparation and evaluation of a novel molecularly imprinted polymer coating for selective extraction of indomethacin from biological samples by electrochemically controlled in-tube solid phase microextraction

    Energy Technology Data Exchange (ETDEWEB)

    Asiabi, Hamid [Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Yamini, Yadollah, E-mail: yyamini@modares.ac.ir [Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Seidi, Shahram; Ghahramanifard, Fazel [Department of Analytical Chemistry, Faculty of Chemistry, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

    2016-03-24

    In the present work, an automated on-line electrochemically controlled in-tube solid-phase microextraction (EC-in-tube SPME) coupled with HPLC-UV was developed for the selective extraction and preconcentration of indomethacin as a model analyte in biological samples. Applying an electrical potential can improve the extraction efficiency and provide more convenient manipulation of different properties of the extraction system including selectivity, clean-up, rate, and efficiency. For more enhancement of the selectivity and applicability of this method, a novel molecularly imprinted polymer coated tube was prepared and applied for extraction of indomethacin. For this purpose, nanostructured copolymer coating consisting of polypyrrole doped with ethylene glycol dimethacrylate was prepared on the inner surface of a stainless-steel tube by electrochemical synthesis. The characteristics and application of the tubes were investigated. Electron microscopy provided a cross linked porous surface and the average thickness of the MIP coating was 45 μm. Compared with the non-imprinted polymer coated tubes, the special selectivity for indomethacin was discovered with the molecularly imprinted coated tube. Moreover, stable and reproducible responses were obtained without being considerably influenced by interferences commonly existing in biological samples. Under the optimal conditions, the limits of detection were in the range of 0.07–2.0 μg L{sup −1} in different matrices. This method showed good linearity for indomethacin in the range of 0.1–200 μg L{sup −1}, with coefficients of determination better than 0.996. The inter- and intra-assay precisions (RSD%, n = 3) were respectively in the range of 3.5–8.4% and 2.3–7.6% at three concentration levels of 7, 70 and 150 μg L{sup −1}. The results showed that the proposed method can be successfully applied for selective analysis of indomethacin in biological samples. - Graphical abstract: An automated on

  5. Braided Composite Technologies for Rotorcraft Structures

    Science.gov (United States)

    Jessie, Nathan

    2015-01-01

    A&P Technology has developed a braided material approach for fabricating lightweight, high-strength hybrid gears for aerospace drive systems. The conventional metallic web was replaced with a composite element made from A&P's quasi-isotropic braid. The 0deg, +/-60deg braid architecture was chosen so that inplane stiffness properties and strength would be nearly equal in all directions. The test results from the Phase I Small Spur Gear program demonstrated satisfactory endurance and strength while providing a 20 percent weight savings. (Greater weight savings is anticipated with structural optimization.) The hybrid gears were subjected to a proof-of-concept test of 1 billion cycles in a gearbox at 10,000 revolutions per minute and 490 in-lb torque with no detectable damage to the gears. After this test the maximum torque capability was also tested, and the static strength capability of the gears was 7x the maximum operating condition. Additional proof-of-concept tests are in progress using a higher oil temperature, and a loss-of-oil test is planned. The success of Phase I led to a Phase II program to develop, fabricate, and optimize full-scale gears, specifically Bull Gears. The design of these Bull Gears will be refined using topology optimization, and the full-scale Bull Gears will be tested in a full-scale gear rig. The testing will quantify benefits of weight savings, as well as noise and vibration reduction. The expectation is that vibration and noise will be reduced through the introduction of composite material in the vibration transmission path between the contacting gear teeth and the shaft-and-bearing system.

  6. Braided Composite Technologies for Rotorcraft Structures

    Science.gov (United States)

    Jessie, Nathan

    2014-01-01

    A&P Technology has developed a braided material approach for fabricating lightweight, high-strength hybrid gears for aerospace drive systems. The conventional metallic web was replaced with a composite element made from A&P's quasi-isotropic braid. The 0deg, plus or minus 60 deg braid architecture was chosen so that inplane stiffness properties and strength would be nearly equal in all directions. The test results from the Phase I Small Spur Gear program demonstrated satisfactory endurance and strength while providing a 20 percent weight savings. (Greater weight savings is anticipated with structural optimization.) The hybrid gears were subjected to a proof-of-concept test of 1 billion cycles in a gearbox at 10,000 revolutions per minute and 490 in-lb torque with no detectable damage to the gears. After this test the maximum torque capability was also tested, and the static strength capability of the gears was 7x the maximum operating condition. Additional proof-of-concept tests are in progress using a higher oil temperature, and a loss-of-oil test is planned. The success of Phase I led to a Phase II program to develop, fabricate, and optimize full-scale gears, specifically Bull Gears. The design of these Bull Gears will be refined using topology optimization, and the full-scale Bull Gears will be tested in a full-scale gear rig. The testing will quantify benefits of weight savings, as well as noise and vibration reduction. The expectation is that vibration and noise will be reduced through the introduction of composite material in the vibration transmission path between the contacting gear teeth and the shaft-and-bearing system.

  7. Numerical Study on the Tensile Behavior of 3D Four Directional Cylindrical Braided Composite Shafts

    Science.gov (United States)

    Zhao, Guoqi; Wang, Jiayi; Hao, Wenfeng; Liu, Yinghua; Luo, Ying

    2017-10-01

    The tensile behavior of 3D four directional cylindrical braided composite shafts was analyzed with the numerical method. The unit cell models for the 3D four directional cylindrical braided composite shafts with various braiding angles were constructed with ABAQUS. Hashin's failure criterion was used to analyze the tensile strength and the damage evolution of the unit cells. The influence of the braiding angle on the tensile behavior of the 3D four directional cylindrical braided composite shafts was analyzed. The numerical results showed that the tensile strength along the braiding direction increased as the braiding angle decreased. These results should play an integral role in the design of braiding composites shafts.

  8. High Resolution Representation and Simulation of Braiding Patterns

    DEFF Research Database (Denmark)

    Zwierzycki, Mateusz; Vestartas, Petras; Heinrich, Mary Katherine

    2017-01-01

    motivates the development of a digital toolset for design exploration. In this paper, we present our underlying methods of braid topology representation and physics-based simulation for hollow tubular braids. We contextualize our approach in the literature where existing methods for this class of problem...

  9. Adaptive Algorithm for the Quality Control of Braided Sleeving

    Directory of Open Access Journals (Sweden)

    Miha Pipan

    2014-09-01

    Full Text Available We describe the development and application of a robot vision based adaptive algorithm for the quality control of the braided sleeving of high pressure hydraulic pipes. With our approach, we can successfully overcome the limitations, such as low reliability and repeatability of braided quality, which result from the visual observation of the braided pipe surface. The braids to be analyzed come in different dimensions, colors, and braiding densities with different types of errors to be detected, as presented in this paper. Therefore, our machine vision system, consisting of a mathematical algorithm for the automatic adaptation to different types of braids and dimensions of pipes, enables the accurate quality control of braided pipe sleevings and offers the potential to be used in the production of braiding lines of pipes. The principles of the measuring method and the required equipment are given in the paper, also containing the mathematical adaptive algorithm formulation. The paper describes the experiments conducted to verify the accuracy of the algorithm. The developed machine vision adaptive control system was successfully tested and is ready for the implementation in industrial applications, thus eliminating human subjectivity.

  10. In-tube solid-phase microextraction with molecularly imprinted polymer to determine interferon alpha 2a in plasma sample by high performance liquid chromatography.

    Science.gov (United States)

    Rodrigues Chaves, Andréa; Costa Queiroz, Maria Eugênia

    2013-11-29

    A molecularly imprinted sol–gel polymer (MIP) based on protein (biopharmaceutical) template with a mild template removal condition using protease was synthetized and evaluated as stationary phase for in-tube solid phase microextraction (in-tube SPME) of the interferon alpha 2a from plasma samples,followed by high performance liquid chromatography analysis with fluorescence detection (HPLC-FD).The developed MIP exhibited high selectivity for the analyte in a complex matrix. The in-tube SPME variables such as draw/eject cycles, draw/eject volume, and desorption conditions were optimized to establish the equilibrium conditions in a short time. The MIP in-tube SPME/HPLC-FD method presented linear response over a dynamic range of 8–300 ng mL−1, with a correlation coefficient of 0.997. The inter-assay precision presented coefficient of variation lower than 9.2%, and accuracy values between 92% and 98%. The developed MIP performed as well as other selective interferon alpha 2a stationary phases (e.g.,immunosorbent and restricted access material), with the advantage that it is robust, easy to handle and cheap to synthesize, in a addition to requiring smaller sample volume (50 L). Based on the analytical validation results, the proposed method (MIP in-tube SPME/HPLC-FD) can be a useful tool to determine interferon alpha 2a in plasma samples from patients receiving therapeutic dosages.

  11. Selective molecularly imprinted polymer combined with restricted access material for in-tube SPME/UHPLC-MS/MS of parabens in breast milk samples

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Israel D.; Melo, Lidervan P. [Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Jardim, Isabel C.S.F. [Instituto de Química, Universidade Estadual de Campinas, Campinas, SP (Brazil); Monteiro, Juliana C.S.; Nakano, Ana Marcia S. [Escola de Enfermagem de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Queiroz, Maria Eugênia C., E-mail: mariaeqn@ffclrp.usp.br [Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2016-08-17

    A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL{sup −1} (LLOQ) to 400 ng mL{sup −1} with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from −1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective. - Highlights: • Molecularly imprinted polymer modified with a hydrophilic external layer (RAM-MIP) was synthesized in a silica capillary. • RAM-MIP capillary, used as sorbent for in-tube SPME, established specific interaction with parabens present in milk samples. • The matrix components that interacted only with the hydrophilic external layer (non-adsorptive network) were excluded.

  12. Structure and properties of braided sleeve preforms for chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L.; Fiadzo, O.G.; Hablutzel, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Technology

    1998-04-01

    In all composites the properties and structure of the reinforcement strongly influence the performance of the material. For some composites, however, the reinforcement also affects the fabrication process itself exerting an additional, second order influence on performance. This is the case for the chemical vapor infiltration (CVI) process for fabrication of ceramic matrix composites. In this process the matrix forms progressively as a solid deposit, first onto the fiber surfaces, then onto the previous layer of deposit, ultimately growing to fill the inter-fiber porosity. The transport of reactants to the surfaces and the evolved morphology of the matrix depend on the initial reinforcement structure. This structure can vary greatly and is controlled by such factors as fiber size and cross-section, the number of filaments and amount of twist per tow or yarn, and the weave or braid architecture. Often the choice of reinforcement is based on mechanical performance analysis or on the cost and availability of the material or on the temperature stability of the fiber. Given this choice, the composite densification process--CVI--must be optimized to attain a successful material. Ceramic fiber in the form of cylindrical braided sleeve is an attractive choice for fabrication of tube-form ceramic matrix composites. Multiple, concentric layers of sleeve can be placed over a tubular mandrel, compressed and fixed with a binder to form a freestanding tube preform. This fiber architecture is different than that created by layup of plain weave cloth--the material used in most previous CVI development. This report presents the results of the investigation of CVI densification of braided sleeve preforms and the evolution of their structure and transport properties during processing.

  13. Modelling of Damage Evolution in Braided Composites: Recent Developments

    Science.gov (United States)

    Wang, Chen; Roy, Anish; Silberschmidt, Vadim V.; Chen, Zhong

    2017-12-01

    Composites reinforced with woven or braided textiles exhibit high structural stability and excellent damage tolerance thanks to yarn interlacing. With their high stiffness-to-weight and strength-to-weight ratios, braided composites are attractive for aerospace and automotive components as well as sports protective equipment. In these potential applications, components are typically subjected to multi-directional static, impact and fatigue loadings. To enhance material analysis and design for such applications, understanding mechanical behaviour of braided composites and development of predictive capabilities becomes crucial. Significant progress has been made in recent years in development of new modelling techniques allowing elucidation of static and dynamic responses of braided composites. However, because of their unique interlacing geometric structure and complicated failure modes, prediction of damage initiation and its evolution in components is still a challenge. Therefore, a comprehensive literature analysis is presented in this work focused on a review of the state-of-the-art progressive damage analysis of braided composites with finite-element simulations. Recently models employed in the studies on mechanical behaviour, impact response and fatigue analyses of braided composites are presented systematically. This review highlights the importance, advantages and limitations of as-applied failure criteria and damage evolution laws for yarns and composite unit cells. In addition, this work provides a good reference for future research on FE simulations of braided composites.

  14. The Imperfect Fluid behind Kinetic Gravity Braiding

    CERN Document Server

    Pujolas, Oriol; Vikman, Alexander

    2011-01-01

    We present a standard hydrodynamical description for non-canonical scalar field theories with kinetic gravity braiding. In particular, this picture applies to the simplest galileons and k-essence. The fluid variables not only have a clear physical meaning but also drastically simplify the analysis of the system. The fluid carries charges corresponding to shifts in field space. This shift-charge current contains a spatial part responsible for diffusion of the charges. Moreover, in the incompressible limit, the equation of motion becomes the standard diffusion equation. The fluid is indeed imperfect because the energy flows neither along the field gradient nor along the shift current. The fluid has zero vorticity and is not dissipative: there is no entropy production, the energy-momentum is exactly conserved, the temperature vanishes and there is no shear viscosity. Still, in an expansion around a perfect fluid one can identify terms which correct the pressure in the manner of bulk viscosity. We close by formul...

  15. New scheme for braiding Majorana fermions

    Science.gov (United States)

    Wu, Long-Hua; Liang, Qi-Feng; Hu, Xiao

    2014-01-01

    Non-Abelian statistics can be achieved by exchanging two vortices in topological superconductors with each grabbing a Majorana fermion (MF) as zero-energy quasi-particle at the cores. However, in experiments it is difficult to manipulate vortices. In the present work, we propose a way to braid MFs without moving vortices. The only operation required in the present scheme is to turn on and off local gate voltages, which liberates a MF from its original host vortex and transports it along the prepared track. We solve the time-dependent Bogoliubov–de Gennes equation numerically, and confirm that the MFs are protected provided the switching of gate voltages for exchanging MFs are adiabatic, which takes only several nano seconds given reasonable material parameters. By monitoring the time evolution of MF wave-functions, we show that non-Abelian statistics is achieved. PMID:27877725

  16. Local unitary representation of braids and N-qubit entanglements

    Science.gov (United States)

    Yu, Li-Wei

    2018-03-01

    In this paper, by utilizing the idea of stabilizer codes, we give some relationships between one local unitary representation of braid group in N-qubit tensor space and the corresponding entanglement properties of the N-qubit pure state |Ψ >, where the N-qubit state |Ψ > is obtained by applying the braiding operation on the natural basis. Specifically, we show that the separability of |Ψ > =B|0> ^{⊗ N} is closely related to the diagrammatic version of the braid operator B. This may provide us more insights about the topological entanglement and quantum entanglement.

  17. Determination of macroscopic electro-mechanical characteristics of 1-3 piezoceramic/polymer composites by a concentric tube model

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1991-01-01

    An axisymmetric concentric tube model of a piezoelectric rod and a concentric elastic tube is used to characterize 1-3 piezoelectric/elastic composites macroscopically. With average displacements of and total forces on the surfaces as the mechanical degrees of freedom, and with charge and potential...... at the ends of the rod as the electrical degrees of freedom, the relation between the electromechanical degrees of freedom is given in a matrix formulation. A recursive numerical scheme for combining the matrix for the tube and the piezoelectric rod into one for the composite piezoelectric rod is used...

  18. Selective molecularly imprinted polymer combined with restricted access material for in-tube SPME/UHPLC-MS/MS of parabens in breast milk samples.

    Science.gov (United States)

    Souza, Israel D; Melo, Lidervan P; Jardim, Isabel C S F; Monteiro, Juliana C S; Nakano, Ana Marcia S; Queiroz, Maria Eugênia C

    2016-08-17

    A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL(-1) (LLOQ) to 400 ng mL(-1) with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from -1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. River channel patterns: Braided, meandering, and straight

    Science.gov (United States)

    Leopold, Luna Bergere; Wolman, M. Gordon

    1957-01-01

    Channel pattern is used to describe the plan view of a reach of river as seen from an airplane, and includes meandering, braiding, or relatively straight channels.Natural channels characteristically exhibit alternating pools or deep reaches and riffles or shallow reaches, regardless of the type of pattern. The length of the pool or distance between riffles in a straight channel equals the straight line distance between successive points of inflection in the wave pattern of a meandering river of the same width. The points of inflection are also shallow points and correspond to riffles in the straight channel. This distance, which is half the wavelength of the meander, varies approximately as a linear function of channel width. In the data we analysed the meander wavelength, or twice the distance between successive riffles, is from 7 to 12 times the channel width. It is concluded that the mechanics which may lead to meandering operate in straight channels.River braiding is characterized by channel division around alluvial islands. The growth of an island begins as the deposition of a central bar which results from sorting and deposition of the coarser fractions of the load which locally cannot be transported. The bar grows downstream and in height by continued deposition on its surface, forcing the water into the flanking channels, which, to carry the flow, deepen and cut laterally into the original banks. Such deepening locally lowers the water surface and the central bar emerges as an island which becomes stabilized by vegetation. Braiding was observed in a small river in a laboratory. Measurements of the adjustments of velocity, depth, width, and slope associated with island development lead to the conclusion that braiding is one of the many patterns which can maintain quasi-equilibrium among discharge, load, and transporting ability. Braiding does not necessarily indicate an excess of total load.Channel cross section and pattern are ultimately controlled by the

  20. Depositional Characteristics of River's Transition from Meander to Braided Belt

    Science.gov (United States)

    Li, Shengli

    2017-04-01

    We describe characteristics of meander-braided transition belt and its sedimentary sequences. We classify abandoned channels into three types: avulsion, chute cut-off and neck cut-off based on the correlation between sinuosity and channel abandonment. Our study on the sedimentary characteristics and river's transitions from proximal to distal zones in Permian fluvial outcrops of the Beijing suburbs leads us to understand the main factor that causes the meander to braided transitions; that is the change in sediment supply, which itself is caused by changes in climate conditions. Three abandoned channels have been distinguished in this outcrop study. Furthermore, we have studied a typical fluvial Permian gas field in the Ordos Basin as an application to subsurface formation. We analyze the distribution of fluvial deposition using meander-braided transition and abandoned channel patterns. Our study has revealed that fluvial changes occurs from braided to meander-braided transition and then to high-sinuosity meandering channel from the northern to the southern part of the study area. Three abandoned channels were identified in the transitional and meandering belts of the gas field. Keywords: Characteristics of Meander-braided Transition; Fluvial Sedimentary Sequence; Abandoned Channel; Permian Fluvial Environment; The Ordos Basin

  1. Prevention of Peritendinous Adhesions Using an Electrospun DegraPol Polymer Tube: A Histological, Ultrasonographic, and Biomechanical Study in Rabbits

    Directory of Open Access Journals (Sweden)

    Gabriella Meier Bürgisser

    2014-01-01

    Full Text Available Purpose. One of the great challenges in surgical tendon rupture repair is to minimize peritendinous adhesions. In order to reduce adhesion formation, a physical barrier was applied to a sutured rabbit Achilles tendon, with two different immobilization protocols used postoperatively. Methods. Thirty New Zealand white rabbits received a laceration on the Achilles tendon, sutured with a 4-strand Becker suture, and half of the rabbits got a DegraPol tube at the repair site. While fifteen rabbits had their treated hind leg in a 180° stretched position during 6 weeks (adhesion provoking immobilization, the other fifteen rabbits were recasted with a 150° position after 3 weeks (adhesion inhibiting immobilization. Adhesion extent was analysed macroscopically, via ultrasound and histology. Inflammation was determined histologically. Biomechanical properties were analysed. Results. Application of a DegraPol tube reduced adhesion formation by approximately 20%—independently of the immobilization protocol. Biomechanical properties of extracted specimen were not affected by the tube application. There was no serious inflammatory reaction towards the implant material. Conclusions. Implantation of a DegraPol tube tightly set around a sutured tendon acts as a beneficial physical barrier and prevents adhesion formation significantly—without affecting the tendon healing process.

  2. Crimped braided sleeves for soft, actuating arm in robotic abdominal surgery.

    Science.gov (United States)

    Elsayed, Yahya; Lekakou, Constantina; Ranzani, Tommaso; Cianchetti, Matteo; Morino, Mario; Arezzo, Alberto; Menciassi, Arianna; Geng, Tao; Saaj, Chakravarthini M

    2015-01-01

    This paper investigates different types of crimped, braided sleeve used for a soft arm for robotic abdominal surgery, with the sleeve required to contain balloon expansion in the pneumatically actuating arm while it follows the required bending, elongation and diameter reduction of the arm. Three types of crimped, braided sleeves from PET (BraidPET) or nylon (BraidGreyNylon and BraidNylon, with different monofilament diameters) were fabricated and tested including geometrical and microstructural characterisation of the crimp and braid, mechanical tests and medical scratching tests for organ damage of domestic pigs. BraidPET caused some organ damage, sliding under normal force of 2-5 N; this was attributed to the high roughness of the braid pattern, the higher friction coefficient of polyethylene terephthalate (PET) compared to nylon, and the high frequency of the crimp peaks for this sleeve. No organ damage was observed for the BraidNylon, attributed to both the lower roughness of the braid pattern and the low friction coefficient of nylon. BraidNylon also required the lowest tensile force during its elongation to similar maximum strain as that of BraidPET, translating to low power requirements. BraidNylon is recommended for the crimped sleeve of the arm designed for robotic abdominal surgery.

  3. An experimental study on mechanical properties of GFRP braid-pultruded composite rods

    Directory of Open Access Journals (Sweden)

    2009-09-01

    Full Text Available In this work, a conventional textile braiding machine was modified and added to a pultrusion line in order to produce glass fiber reinforced composite rods by braiding-pultrusion technique. Braid-pultruded (BP rods were produced with three braid roving linear densities and also with three different braid angles. To study the influence of overbraiding on mechanical properties of pultruded rods, unidirectional (UD rods, without braided fabric, were produced, as well. All rod types were subjected to tensile, bending and torsion tests. The experimental results showed that BP rods have considerably higher shear modulus, but lower tensile modulus and flexural rigidity than those of UD pultruded rods, when fiber volume fraction is kept constant. Moreover, rods produced with higher braid roving linear densities had better torsional, but lower tensile and flexural properties. The highest shear modulus was observed in BP rods with braid angle of 45°.

  4. Restoration of Impaired Metabolic Energy Balance (ATP Pool and Tube Formation Potential of Endothelial Cells under “high glucose”, Diabetic Conditions by the Bioinorganic Polymer Polyphosphate

    Directory of Open Access Journals (Sweden)

    Xiaohong Wang

    2017-11-01

    Full Text Available Micro-vascularization is a fast, energy-dependent process that is compromised by elevated glucose concentrations such as in diabetes mellitus disease. Here, we studied the effect of the physiological bioinorganic polymer, polyphosphate (polyP, on the reduced ATP content and impaired function of endothelial cells cultivated under “high glucose” (35 mM diabetes mellitus conditions concentrations. This high-energy biopolymer has been shown to provide a source of metabolic energy, stored in its phosphoanhydride bonds. We show that exposure of human umbilical vein endothelial cells (HUVEC cells to “high glucose” levels results in reduced cell viability, increased apoptotic cell death, and a decline in intracellular ATP level. As a consequence, the ability of HUVEC cells to form tube-like structures in the in vitro cell tube formation assay was almost completely abolished under “high glucose” conditions. Those cells were grown onto a physiological collagen scaffold (collagen/basement membrane extract. We demonstrate that these adverse effects of increased glucose levels can be reversed by administration of polyP to almost normal values. Using Na-polyP, complexed in a stoichiometric (molar ratio to Ca2+ ions and in the physiological concentration range between 30 and 300 µM, an almost complete restoration of the reduced ATP pool of cells exposed to “high glucose” was found, as well as a normalization of the number of apoptotic cells and energy-dependent tube formation. It is concluded that the adverse effects on endothelial cells caused by the metabolic energy imbalance at elevated glucose concentrations can be counterbalanced by polyP, potentially opening new strategies for treatment of the micro-vascular complications in diabetic patients.

  5. The braided Ptolemy-Thompson group $T^*$ is asynchronously combable

    OpenAIRE

    Funar, Louis; Kapoudjian, Christophe

    2006-01-01

    The braided Ptolemy-Thompson group $T^*$ is an extension of the Thompson group $T$ by the full braid group $B_{\\infty}$ on infinitely many strands. This group is a simplified version of the acyclic extension considered by Greenberg and Sergiescu, and can be viewed as a mapping class group of a certain infinite planar surface. In a previous paper we showed that $T^*$ is finitely presented. Our main result here is that $T^*$ (and $T$) is asynchronously combable. The method of proof is inspired ...

  6. "On the braided Fourier transform in the n-dimensional quantum space"

    NARCIS (Netherlands)

    Carnovale, G.

    1998-01-01

    We work out in detail a theory of integrability on the braided covector Hopf algebra and the braided vector Hopf algebra of type An introduced in Ma and KeMa Starting with a denition of braided Fourier transform very similar to that in KeMa we obtain ndimensional analogous results to those in Koo

  7. High Speed Thermal Imaging on Ballistic Impact of Triaxially Braided Composites

    Science.gov (United States)

    Johnston, Joel P.; Pereira, J. Michael; Ruggeri, Charles R.; Roberts, Gary D.

    2017-01-01

    Ballistic impact experiments were performed on triaxially braided polymer matrix composites to study the heat generated in the material due to projectile velocity and penetration damage. Quantifying the heat generation phenomenon is crucial for attaining a better understanding of composite behavior and failure under impact loading. The knowledge gained can also be used to improve physics-based models which can numerically simulate impact of composites. Triaxially braided (0/+60/-60) composite panels were manufactured with T700S standard modulus carbon fiber and two epoxy resins. The PR520 (toughened) and 3502 (untoughened) resin systems were used to make different panels to study the effects of resin properties on temperature rise. Ballistic impact tests were conducted on these composite panels using a gas gun, and different projectile velocities were applied to study the effect on the temperature results. Temperature contours were obtained from the rear surface of the panel during the test through a high speed, infrared (IR) thermal imaging system. The contours show that high temperatures were locally generated and more pronounced along the axial tows for the T700S/PR520 composite specimens; whereas, tests performed on T700S/3502 composite panels using similar impact velocities demonstrated a widespread area of lower temperature rises. Nondestructive, ultrasonic C-scan analyses were performed to observe and verify the failure patterns in the impacted panels. Overall, the impact experimentation showed temperatures exceeding 525 K (485degF) in both composites which is well above the respective glass transition temperatures for the polymer constituents. This expresses the need for further high strain rate testing and measurement of the temperature and deformation fields to fully understand the complex behavior and failure of the material in order to improve the confidence in designing aerospace components with these materials.

  8. Mechanical Properties of Triaxial Braided Carbon/Epoxy Composites

    Science.gov (United States)

    Bowman, C. L.; Roberts, G. D.; Braley, M. S.; Xie, M.; Booker, M. J.

    2003-01-01

    In an on-going effort to increase the safety and efficiency of turbine engines, the National Aeronautics and Space Administration is exploring lightweight alternatives to the metal containment structures that currently encase commercial jet engines. Epoxy reinforced with braided carbon fibers is a candidate structural material which may be suitable for an engine case. This paper reports flat-coupon mechanical-property experiments performed to compliment previously reported subcomponent impact testing and analytical simulation of containment structures. Triaxial-braid T700/5208 epoxy and triaxial-braid T700/M36 toughened epoxy composites were evaluated. Also, two triaxial-braid architectures (0 +/- 60 deg., 0 +/- 45 deg.) with the M36 resin were evaluated through tension, compression, and shear testing. Tensile behavior was compared between standard straight-sided specimens (ASTM D3039) and bowtie specimens. Both double-notch shear (ASTM D3846) and Iosepescu (ASTM D5379) tests were performed as well. The M36/0 +/- 45 deg. configuration yield the best response when measurements were made parallel to the axial tows. Conversely, the M36/0 +/- 60 deg. configuration was best when measurements were made perpendicular to the axial tows. The results were used to identify critical properties and to augment the analysis of impact experiments.

  9. Circular braiding take-up speed generation using inverse kinematics

    NARCIS (Netherlands)

    van Ravenhorst, J.H.; Akkerman, Remko

    2014-01-01

    Circular overbraiding of composite preforms on complex mandrels currently lacks automatic generation of machine control data. To solve this limitation, an inverse kinematics-based procedure was designed and implemented for circular braiding machines with optional guide rings, resulting in a take-up

  10. Braid group, knot theory and statistical mechanics II

    CERN Document Server

    Yang Chen Ning

    1994-01-01

    The present volume is an updated version of the book edited by C N Yang and M L Ge on the topics of braid groups and knot theory, which are related to statistical mechanics. This book is based on the 1989 volume but has new material included and new contributors.

  11. Braid My Hair - Randy Owen sings out for sick children

    Science.gov (United States)

    ... about a young girl who has lost her hair due to illness. Chris Gray and Brent Wilson wrote the song. Gray had been a teacher at St. Jude helping kids there who were being treated for ... girls longed to have hair to braid again. The songwriters managed to get ...

  12. Mechanical characterization of 2D, 2D stitched, and 3D braided/RTM materials

    Science.gov (United States)

    Deaton, Jerry W.; Kullerd, Susan M.; Portanova, Marc A.

    1993-01-01

    Braided composite materials have potential for application in aircraft structures. Fuselage frames, floor beams, wing spars, and stiffeners are examples where braided composites could find application if cost effective processing and damage tolerance requirements are met. Another important consideration for braided composites relates to their mechanical properties and how they compare to the properties of composites produced by other textile composite processes being proposed for these applications. Unfortunately, mechanical property data for braided composites do not appear extensively in the literature. Data are presented in this paper on the mechanical characterization of 2D triaxial braid, 2D triaxial braid plus stitching, and 3D (through-the-thickness) braid composite materials. The braided preforms all had the same graphite tow size and the same nominal braid architectures, (+/- 30 deg/0 deg), and were resin transfer molded (RTM) using the same mold for each of two different resin systems. Static data are presented for notched and unnotched tension, notched and unnotched compression, and compression after impact strengths at room temperature. In addition, some static results, after environmental conditioning, are included. Baseline tension and compression fatigue results are also presented, but only for the 3D braided composite material with one of the resin systems.

  13. Experimental and Analytical Characterization of the Macromechanical Response for Triaxial Braided Composite Materials

    Science.gov (United States)

    Littell, Justin D.

    2013-01-01

    Increasingly, carbon composite structures are being used in aerospace applications. Their highstrength, high-stiffness, and low-weight properties make them good candidates for replacing many aerospace structures currently made of aluminum or steel. Recently, many of the aircraft engine manufacturers have developed new commercial jet engines that will use composite fan cases. Instead of using traditional composite layup techniques, these new fan cases will use a triaxially braided pattern, which improves case performance. The impact characteristics of composite materials for jet engine fan case applications have been an important research topic because Federal regulations require that an engine case be able to contain a blade and blade fragments during an engine blade-out event. Once the impact characteristics of these triaxial braided materials become known, computer models can be developed to simulate a jet engine blade-out event, thus reducing cost and time in the development of these composite jet engine cases. The two main problems that have arisen in this area of research are that the properties for these materials have not been fully determined and computationally efficient computer models, which incorporate much of the microscale deformation and failure mechanisms, are not available. The research reported herein addresses some of the deficiencies present in previous research regarding these triaxial braided composite materials. The current research develops new techniques to accurately quantify the material properties of the triaxial braided composite materials. New test methods are developed for the polymer resin composite constituent and representative composite coupons. These methods expand previous research by using novel specimen designs along with using a noncontact measuring system that is also capable of identifying and quantifying many of the microscale failure mechanisms present in the materials. Finally, using the data gathered, a new hybrid

  14. The Effects of Hygrothermal Aging on the Impact Penetration Resistance of Triaxially Braided Composites

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.; Ruggeri, Charles R.; Roberts, Gary D.; Kohlman, Lee W.; Miller, Sandi G.

    2016-01-01

    An experimental study was conducted to measure the effects of long term hygrothermal aging on the impact penetration resistance of triaxially braided polymer composites. Flat panels of three different materials were subjected to repeated cycles of high and low temperature and high and low humidity for two years. Samples of the panels were periodically tested under impact loading during the two year time period. The purpose of the study was to identify and quantify any degradation in impact penetration resistance of these composites under cyclic temperature and humidity conditions experienced by materials in the fan section of commercial gas turbine engines for a representative aircraft flight cycle. The materials tested consisted of Toray ® T700S carbon fibers in a 2D triaxial braid with three different resins, Cycom® PR520, a toughened resin, Hercules® 3502, an untoughened resin and EPON 862, intermediate between the two. The fiber preforms consisted of a quasi-isotropic 0/+60/-60 braid with 24K tows in the axial direction and 12K tows in the bias directions. The composite panels were manufactured using a resin transfer molding process producing panels with a thickness of 0.125 inches. The materials were tested in their as-processed condition and again after one year and two years of aging (1.6 years in the case of E862). The aging process involved subjecting the test panels to two cycles per day of high and low temperature and high and low humidity. A temperature range of -60degF to 250degF and a humidity range of 0 to 85% rh was used to simulate extreme conditions for composite components in the fan section of a commercial gas turbine engine. Additional testing was conducted on the as-processed PR520 composite under cryogenic conditions. After aging there was some change in the failure pattern, but there was no reduction in impact penetration threshold for any of the three systems, and in the case of the 3502 system, a significant increase in penetration

  15. Chiral braided and woven composites: design, fabrication, and electromagnetic characterization

    Science.gov (United States)

    Wheeland, Sara; Bayatpur, Farhad; Amirkhizi, Alireza V.; Nemat-Nasser, Sia

    2011-04-01

    This work presents a new chiral composite composed of copper wires braided with Kevlar and nylon to form conductive coils integrated among structural fiber. To create a fabric, these braids were woven with plain Kevlar fiber. This yielded a composite with all coils possessing the same handedness, producing a chiral material. The electromagnetic response of this fabric was first simulated using a finite element full-wave simulation. For the electromagnetic measurement, the sample was placed between two lens-horn antennas connected to a Vector Network Analyzer. The frequency response of the sample was scanned between 5.5 and 8GHz. The measured scattering parameters were then compared to those of the simulated model. The measured parameters agreed well with the simulation results, showing a considerable chirality within the measured frequency band. The new composite combines the strength and durability of traditional composites with an electromagnetic design to create a multifunctional material.

  16. Modeling of Moisture Diffusion in Carbon Braided Composites

    Directory of Open Access Journals (Sweden)

    S. Laurenzi

    2008-01-01

    Full Text Available In this study, we develop a methodology based on finite element analysis to predict the weight gain of carbon braided composite materials exposed to moisture. The analysis was based on the analogy between thermal conduction and diffusion processes, which allowed for a commercial code for finite element analysis to be used. A detailed finite element model using a repetitive unit cell (RUC was developed both for bundle and carbon braided composites. Conditioning tests were performed to estimate the diffusivity of both the resin and composite. When comparing numerical and experimental results, it was observed that the procedure introduces an average error of 20% and a maximum error of 31% if the RUC is assumed to be isotropic. On the other hand, the average error does not exceed 10% and the maximum error is less than 20% when the material is considered as orthotropic. The procedure is independent of the particular fiber architecture and can be extended to other composites.

  17. Noncommutative Independence from the Braid Group {mathbb{B}_{infty}}

    Science.gov (United States)

    Gohm, Rolf; Köstler, Claus

    2009-07-01

    We introduce ‘braidability’ as a new symmetry for infinite sequences of noncommutative random variables related to representations of the braid group {mathbb{B}_{infty}} . It provides an extension of exchangeability which is tied to the symmetric group {mathbb{S}_{infty}} . Our key result is that braidability implies spreadability and thus conditional independence, according to the noncommutative extended de Finetti theorem [Kös08]. This endows the braid groups {mathbb{B}n} with a new intrinsic (quantum) probabilistic interpretation. We underline this interpretation by a braided extension of the Hewitt-Savage Zero-One Law. Furthermore we use the concept of product representations of endomorphisms [Goh04] with respect to certain Galois type towers of fixed point algebras to show that braidability produces triangular towers of commuting squares and noncommutative Bernoulli shifts. As a specific case we study the left regular representation of {mathbb{B}_{infty}} and the irreducible subfactor with infinite Jones index in the non-hyperfinite I I 1-factor L {(mathbb{B}_{infty})} related to it. Our investigations reveal a new presentation of the braid group {mathbb{B}_{infty}} , the ‘square root of free generator presentation’ {mathbb{F}^{1/2}_{infty}} . These new generators give rise to braidability while the squares of them yield a free family. Hence our results provide another facet of the strong connection between subfactors and free probability theory [GJS07]; and we speculate about braidability as an extension of (amalgamated) freeness on the combinatorial level.

  18. Perception, Action, and Experience: Unraveling the Golden Braid

    Science.gov (United States)

    Clark, Andy

    2009-01-01

    Much of our human mental life looks to involve a seamless unfolding of perception, action and experience: a golden braid in which each element twines intimately with the rest. We see the very world we act in and we act in the world we see. But more than this, visual experience presents us with the world in a way apt for the control and fine…

  19. Modelling of vegetation-driven morphodynamics in braided rivers.

    Science.gov (United States)

    Stecca, Guglielmo; Fedrizzi, Davide; Hicks, Murray; Measures, Richard; Zolezzi, Guido; Bertoldi, Walter; Tal, Michal

    2017-04-01

    River planform results from the complex interaction between flow, sediment transport and vegetation, and can evolve following a change in these controls. The braided planform of New Zealand's Lower Waitaki River, for instance, is endangered by the action of artificially-introduced alien vegetation, which spread across the braidplain following the reduction in magnitude of floods by hydropower dam construction. This vegetation, by encouraging flow concentration into the main channel, would likely promote a shift towards a single-thread morphology if it was not artificially removed within a central fairway. The purpose of this work is to study the evolution of braided rivers such as the Waitaki under different management scenarios through two-dimensional numerical modelling. The construction of a suitable model represents a task in itself, since a modelling framework coupling all the relevant processes is not yet readily available. Our starting point is the physics-based GIAMT2D numerical model, which solves two-dimensional flow and bedload transport in wet/dry domains, and recently modified by the inclusion of a rule-based bank erosion model. We have further developed this model by adding a vegetation module, which accounts in a simplified manner for time-evolving biomass density, adjusting local flow roughness, critical shear stress for sediment transport, and bank erodibility accordingly. Our goal is to use the model to study decadal-scale evolution of a reach on the Waitaki River and predict planform characteristics under different vegetation management scenarios. Here we present the results of a preliminary application of the model to reproduce the morphodynamic evolution of a braided channel in a set of flume experiments that used alfalfa as vegetation. The experiments began with a braided morphology that spontaneoulsy formed at constant flow over a bed of bare uniform sand. The planform transitioned towards single-thread when this discharge was repeatedly

  20. Characterization of Triaxial Braided Composite Material Properties for Impact Simulation

    Science.gov (United States)

    Roberts, Gary D.; Goldberg, Robert K.; Biniendak, Wieslaw K.; Arnold, William A.; Littell, Justin D.; Kohlman, Lee W.

    2009-01-01

    The reliability of impact simulations for aircraft components made with triaxial braided carbon fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Improvements to standard quasi-static test methods are needed to account for the large unit cell size and localized damage within the unit cell. The deformation and damage of a triaxial braided composite material was examined using standard quasi-static in-plane tension, compression, and shear tests. Some modifications to standard test specimen geometries are suggested, and methods for measuring the local strain at the onset of failure within the braid unit cell are presented. Deformation and damage at higher strain rates is examined using ballistic impact tests on 61- by 61- by 3.2-mm (24- by 24- by 0.125-in.) composite panels. Digital image correlation techniques were used to examine full-field deformation and damage during both quasi-static and impact tests. An impact analysis method is presented that utilizes both local and global deformation and failure information from the quasi-static tests as input for impact simulations. Improvements that are needed in test and analysis methods for better predictive capability are examined.

  1. A physical model of driftwood-rich braided rivers

    Science.gov (United States)

    Welber, M.; Bertoldi, W.; Tubino, M.

    2012-04-01

    In riverine systems, strong links and feedbacks between driftwood dynamics and river morphodynamics and ecology have been observed. Wood influences fluvial dynamics by interacting with water flow, sediment transport and standing vegetation; conversely, its dispersal is governed by river morphology and flow regime. These interactions are especially intense in braided systems characterized by a high level of connectivity between the riparian forest and the active tract which may include vegetated islands. This study focuses on wood dispersal and sediment transport in braided systems and aims to investigate their governing factors and mutual feedback processes. Physical modelling was performed in a 3x25 m laboratory facility located at the University of Trento, Italy. The flume was set up to reproduce typical discharges and slopes of natural gravel-bed braided rivers. To investigate the effect of log properties on wood dispersal, cylindrical wooden dowels of various sizes were used as surrogate logs. Cross-shaped bases were added to reproduce the effect of root boles. Wood input to the network under constant flow conditions produces consistent patterns of accumulations that highlight typical retentive sites. Moreover, floods were investigated as the main driver of wood and sediment transport. Rapid discharge pulses were simulated and both bed topography and wood deposits were surveyed before and after each event using digital imagery and laser profiler. Map analysis in a GIS framework shows clear links between scour and deposition areas and wood deposition and remobilization patterns.

  2. A novel ionic liquid-modified organic-polymer monolith as the sorbent for in-tube solid-phase microextraction of acidic food additives.

    Science.gov (United States)

    Wang, Ting-Ting; Chen, Yi-Hui; Ma, Jun-Feng; Hu, Min-Jie; Li, Ying; Fang, Jiang-Hua; Gao, Hao-Qi

    2014-08-01

    A novel ionic liquid-modified organic-polymer monolithic capillary column was prepared and used for in-tube solid-phase microextraction (SPME) of acidic food additives. The primary amino group of 1-aminopropyl-3-methylimidazolium chloride was reacted with the epoxide group of glycidyl methacrylate. The as-prepared new monomer was then copolymerized in situ with acrylamide and N,N'-methylenebisacrylamide in the presence of polyethylene glycol (PEG)-8000 and PEG-10,000 as porogens. The extraction performance of the developed monolithic sorbent was evaluated for benzoic acid, 3-hydroxybenzoic acid, cinnamic acid, 2,4-dichlorophenoxyacetic acid, and 3-(trifluoromethyl)-cinnamic acid. Such a sorbent, bearing hydrophobic and anion-exchange groups, had high extraction efficiency towards the test compounds. The adsorption capacities for the analytes dissolved in water ranged from 0.18 to 1.74 μg cm(-1). Good linear calibration curves (R(2) > 0.99) were obtained, and the limits of detection (S/N = 3) for the analytes were found to be in the range 1.2-13.5 ng mL(-1). The recoveries of five acidic food additives spiked in Coca-Cola beverage samples ranged from 85.4 % to 98.3 %, with RSD less than 6.9 %. The excellent applicability of the ionic liquid (IL)-modified monolithic column was further tested by the determination of benzoic acid content in Sprite samples, further illustrating its good potential for analyzing food additives in complex samples.

  3. In-tube solid-phase microextraction and liquid chromatography using a monolithic column for the selective determination of residual ethylenediamine in industrial cationic polymers.

    Science.gov (United States)

    Prieto-Blanco, M C; López-Mahía, P; Campíns-Falcó, P

    2009-07-15

    The selective determination of the diamine ethylenediamine (EDA) in the presence of a higher amount of residual dimethylamine in cationic polymers has been developed. The strategy uses both a solution derivatization with a selective agent of primary amines such as o-phthaldialdehyde-N-acetyl-L-cysteine (OPA-NAC) and an in-tube solid-phase microextraction (IT-SPME) coupled to liquid chromatography (LC). A 70 cm long, 0.32 mm internal diameter, and 3 microm thick commercially available capillary column coated with 95% polydimethylsiloxane and 5% polydiphenylsiloxane was employed to replace the injection loop of a Rheodyne injection valve. A volume of 1 mL of derivatized sample was passed through the capillary, and 100 microL of water was later used for cleaning and filling the capillary. After, the injection was effected and the desorption of the derivative from the capillary was carried out in the dynamic mode using the mobile phase. Chromatographic separation was performed in less than 2 min using a monolithic silica column Onyx (100 mm x 3.0 mm i.d.) under isocratic conditions. The effect of several parameters affecting derivatization and IT-SPME was investigated. The quantification of EDA was realized over the range of 0.07-2 microg/mL with adequate linearity, accuracy, and reproducibility, and the limit of detection was 20 ng/mL. The method is rapid and low in cost, and sample handling and organic solvent consumption have been minimized. Its application to polymeric cationic surfactants used in water treatment allowed the selective quantification of residual EDA at low microgram per milliliter levels of concentration without off-line preconcentration.

  4. Covalent Percolation and Gold Templating of Carbon NanoTubes Network in Polymer Nanocomposites for Novel Mechanical, Electrical, and Optical Properties. Taiwain - US AFOSR Nanoscience Initiative

    National Research Council Canada - National Science Library

    Yang, Arnold C

    2008-01-01

    ...) in nanocomposites were investigated by using two model polymer systems, polystyrene and poly(phenylene oxide) representing respectively the ductile and brittle polymers, with surface-grafted multiwalled CNTs.

  5. TUBE TESTER

    Science.gov (United States)

    Gittings, H.T. Jr.; Kalbach, J.F.

    1958-01-14

    This patent relates to tube testing, and in particular describes a tube tester for automatic testing of a number of vacuum tubes while in service and as frequently as may be desired. In it broadest aspects the tube tester compares a particular tube with a standard tube tarough a difference amplifier. An unbalanced condition in the circuit of the latter produced by excessive deviation of the tube in its characteristics from standard actuates a switch mechanism stopping the testing cycle and indicating the defective tube.

  6. Asymptotic Analysis and Spatial Coupling of Counter Braids

    OpenAIRE

    Rosnes, Eirik; Amat, Alexandre Graell i

    2016-01-01

    A counter braid (CB) is a novel counter architecture introduced by Lu et al. in 2007 for per-flow measurements on high-speed links. CBs achieve an asymptotic compression rate (under optimal decoding) that matches the entropy lower bound of the flow size distribution. In this paper, we apply the concept of spatial coupling to CBs to improve their belief propagation (BP) threshold, and analyze the performance of the resulting spatially-coupled CBs (SC-CBs). We introduce an equivalent bipartite ...

  7. Complete braided adsorbent for marine testing to demonstrate 3g-U/kg-adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Chris [ORNL; Yatsandra, Oyola [ORNL; Mayes, Richard [ORNL; none,; Gill, Gary [PNNL; Li-Jung, Kuo [PNNL; Wood, Jordana [PNNL; Sadananda, Das [ORNL

    2014-04-30

    ORNL has manufactured four braided adsorbents that successfully demonstrated uranium adsorption capacities ranging from 3.0-3.6 g-U/kg-adsorbent in marine testing at PNNL. Four new braided and leno woven fabric adsorbents have also been prepared by ORNL and are currently undergoing marine testing at PNNL.

  8. Braided multi-electrode probes: mechanical compliance characteristics and recordings from spinal cords

    Science.gov (United States)

    Kim, Taegyo; Branner, Almut; Gulati, Tanuj; Giszter, Simon F.

    2013-08-01

    Objective. To test a novel braided multi-electrode probe design with compliance exceeding that of a 50 µm microwire, thus reducing micromotion- and macromotion-induced tissue stress. Approach. We use up to 24 ultra-fine wires interwoven into a tubular braid to obtain a highly flexible multi-electrode probe. The tether-portion wires are simply non-braided extensions of the braid structure, allowing the microprobe to follow gross neural tissue movements. Mechanical calculation and direct measurements evaluated bending stiffness and axial compression forces in the probe and tether system. These were compared to 50 µm nichrome microwire standards. Recording tests were performed in decerebrate animals. Main results. Mechanical bending tests on braids comprising 9.6 or 12.7 µm nichrome wires showed that implants (braided portions) had 4 to 21 times better mechanical compliance than a single 50 µm wire and non-braided tethers were 6 to 96 times better. Braided microprobes yielded robust neural recordings from animals' spinal cords throughout cord motions. Significance. Microwire electrode arrays that can record and withstand tissue micro- and macromotion of spinal cord tissues are demonstrated. This technology may provide a stable chronic neural interface into spinal cords of freely moving animals, is extensible to various applications, and may reduce mechanical tissue stress.

  9. Evaluation of Test Methods for Triaxially Braided Composites using a Meso-Scale Finite Element Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao

    2015-10-01

    The characterization of triaxially braided composite is complicate due to the nonuniformity of deformation within the unit cell as well as the possibility of the freeedge effect related to the large size of the unit cell. Extensive experimental investigation has been conducted to develop more accurate test approaches in characterizing the actual mechanical properties of the material we are studying. In this work, a meso-scale finite element model is utilized to simulate two complex specimens: notched tensile specimen and tube tensile specimen, which are designed to avoid the free-edge effect and free-edge effect induced premature edge damage. The full field strain data is predicted numerically and compared with experimental data obtained by Digit Image Correlation. The numerically predicted tensile strength values are compared with experimentally measured results. The discrepancy between numerically predicted and experimentally measured data, the capability of different test approaches are analyzed and discussed. The presented numerical model could serve as assistance to the evaluation of different test methods, and is especially useful in identifying potential local damage events.

  10. Complexity of coherent structures computed from braids of passive particles

    Science.gov (United States)

    Budisic, Marko; Thiffeault, Jean-Luc

    2015-11-01

    Transport in fluids can be characterized by tracking passive particles advected by the fluid flow. When particles are distributed densely, as can be achieved in laboratory, the fluid velocity field can be reconstructed through Particle Tracking Velocimetry, enabling computation of Lyapunov exponents or other numerical analyses. When particles are sparse, as in drifter measurements of oceans, the velocity field cannot be reliably reconstructed. Nevertheless, the amount of entanglement of particle paths over time can be used to estimate the dynamical complexity of the flow by computing the Finite-Time Braiding Exponent (FTBE). The technique is based on braid dynamics and measures the rate at which particle motion stretches topological loops, i.e., the ``rubber bands'' enclosing subsets of particles. Allshouse and Thiffeault showed that minimally-stretching loops correspond to the structures coherent under material transport in flows. We extend their work and couple it to the FTBE calculations in order to characterize the spatial distribution of flow complexity. Analysis is demonstrated on the Hackborn rotor-oscillator model, which exhibits regions of chaotic and regular dynamics, and can be realized both numerically and experimentally. Funded by NSF CMMI-1233935.

  11. Macro Scale Independently Homogenized Subcells for Modeling Braided Composites

    Science.gov (United States)

    Blinzler, Brina J.; Goldberg, Robert K.; Binienda, Wieslaw K.

    2012-01-01

    An analytical method has been developed to analyze the impact response of triaxially braided carbon fiber composites, including the penetration velocity and impact damage patterns. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. Currently, each shell element is considered to be a smeared homogeneous material. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. To determine the stiffness and strength properties required for the constitutive model, a top-down approach for determining the strength properties is merged with a bottom-up approach for determining the stiffness properties. The top-down portion uses global strengths obtained from macro-scale coupon level testing to characterize the material strengths for each subcell. The bottom-up portion uses micro-scale fiber and matrix stiffness properties to characterize the material stiffness for each subcell. Simulations of quasi-static coupon level tests for several representative composites are conducted along with impact simulations.

  12. Multi-Scale Modeling of an Integrated 3D Braided Composite with Applications to Helicopter Arm

    Science.gov (United States)

    Zhang, Diantang; Chen, Li; Sun, Ying; Zhang, Yifan; Qian, Kun

    2017-10-01

    A study is conducted with the aim of developing multi-scale analytical method for designing the composite helicopter arm with three-dimensional (3D) five-directional braided structure. Based on the analysis of 3D braided microstructure, the multi-scale finite element modeling is developed. Finite element analysis on the load capacity of 3D five-directional braided composites helicopter arm is carried out using the software ABAQUS/Standard. The influences of the braiding angle and loading condition on the stress and strain distribution of the helicopter arm are simulated. The results show that the proposed multi-scale method is capable of accurately predicting the mechanical properties of 3D braided composites, validated by the comparison the stress-strain curves of meso-scale RVCs. Furthermore, it is found that the braiding angle is an important factor affecting the mechanical properties of 3D five-directional braided composite helicopter arm. Based on the optimized structure parameters, the nearly net-shaped composite helicopter arm is fabricated using a novel resin transfer mould (RTM) process.

  13. Self-consistent treatment of electrostatics in molecular DNA braiding through external forces.

    Science.gov (United States)

    Lee, Dominic J

    2014-06-01

    In this paper we consider a physical system in which two DNA molecules braid about each other. The distance between the two molecular ends, on either side of the braid, is held at a distance much larger than supercoiling radius of the braid. The system is subjected to an external pulling force, and a moment that induces the braiding. In a model, developed for understanding such a system, we assume that each molecule can be divided into a braided and unbraided section. We also suppose that the DNA is nicked so that there is no constraint of the individual linking numbers of the molecules. Included in the model are steric and electrostatic interactions, thermal fluctuations of the braided and unbraided sections of the molecule, as well as the constraint on the braid linking (catenation) number. We compare two approximations used in estimating the free energy of the braided section. One is where the amplitude of undulations of one molecule with respect to the other is determined only by steric interactions. The other is a self-consistent determination of the mean-squared amplitude of these undulations. In this second approximation electrostatics should play an important role in determining this quantity, as suggested by physical arguments. We see that if the electrostatic interaction is sufficiently large there are indeed notable differences between the two approximations. We go on to test the self-consistent approximation-included in the full model-against experimental data for such a system, and we find good agreement. However, there seems to be a slight left-right-handed braid asymmetry in some of the experimental results. We discuss what might be the origin of this small asymmetry.

  14. RTM370 Polyimide Braided Composites: Characterization and Impact Testing

    Science.gov (United States)

    Chuang, Kathy C.; Revilock, Duane M.; Ruggeri, Charles R.; Criss, Jim M., Jr.; Mintz, Eric A.

    2013-01-01

    RTM370 imide oligomer based on 2,3,3',4'-biphenyl dianhydride (a-BPDA), 3,4'-oxydianiline (3,4'-ODA) and terminated with the 4-phenylethynylphthalic (PEPA) endcap has been shown to exhibit a low melt viscosity (10-30 poise) at 280 C with a pot-life of 1-2 h and a high cured glass transition temperature (Tg) of 370 C. RTM370 resin has been successfully fabricated into composites reinforced with T650-35 carbon fabrics by resin transfer molding (RTM). RTM370 composites display excellent mechanical properties up to 327 C (620 F), and outstanding property retention after aging at 288degC (550 F) for 1000 h, and under hot-wet conditions. In ballistic impact testing, RTM370 triaxial braided T650-35 carbon fiber composites exhibited enhanced energy absorption at 288 C (550 F) compared to ambient temperature.

  15. Braided Categories of Endomorphisms as Invariants for Local Quantum Field Theories

    Science.gov (United States)

    Giorgetti, Luca; Rehren, Karl-Henning

    2017-08-01

    We want to establish the "braided action" (defined in the paper) of the DHR category on a universal environment algebra as a complete invariant for completely rational chiral conformal quantum field theories. The environment algebra can either be a single local algebra, or the quasilocal algebra, both of which are model-independent up to isomorphism. The DHR category as an abstract structure is captured by finitely many data (superselection sectors, fusion, and braiding), whereas its braided action encodes the full dynamical information that distinguishes models with isomorphic DHR categories. We show some geometric properties of the "duality pairing" between local algebras and the DHR category that are valid in general (completely rational) chiral CFTs. Under some additional assumptions whose status remains to be settled, the braided action of its DHR category completely classifies a (prime) CFT. The approach does not refer to the vacuum representation, or the knowledge of the vacuum state.

  16. Channel morphodynamics on a small proglacial braid plain (Fagge River, Gepatschferner, Austria

    Directory of Open Access Journals (Sweden)

    D. Morche

    2015-03-01

    Full Text Available Braid plains are important sediment stores in high mountains, particularly in the glacier forefields of Alpine glaciers. Proglacial braid plains receive sediment input from glacial meltwater and proglacial sediment sources like moraines and glacio-fluvial deposits. The channel morphodynamics on the braid plains are strongly related to the sediment transport and flow regime of the proglacial river. This study deals with channel morphodynamics on a small proglacial braid plain in the European Alps. It focuses on two different time scales. Decadal channel planform changes were assessed by remote sensing approaches. The recent channel bed changes were investigated by cross-sectional surveys and particle counts in 2013. This study is part of the DFG/FWF funded interdisciplinary research project PROSA (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps.

  17. Suture complications in a teaching institution among patients undergoing uterosacral ligament suspension with permanent braided suture

    OpenAIRE

    Yazdany, Tajnoos; Yip, Sallis; Bhatia, Narender N.; Nguyen, John N.

    2010-01-01

    Introduction and hypothesis Our study aimed to identify the rate of suture complications over a 5-year period using braided permanent suture for uterosacral ligament suspension (USLS) surgery. Methods We reviewed the medical records of patients who underwent vaginal uterosacral ligament suspensions using braided polyester suture. Outcome measures included rate and timing of suture complications, patient symptoms post-operatively, efficacy of treatment modalities and surgical success. Results ...

  18. Assessment of intermediate fine sediment storage in a braided river reach (southern French Prealps)

    OpenAIRE

    Navratil, Oldrich; Legout, C.; Gateuille, D.; Esteves, Michel; Liebault, F.

    2010-01-01

    This paper presents a field investigation on river channel storage of fine sediments in an unglaciated braided river, the Bes River, located in a mountainous region in the southern French Prealps. Braided rivers transport a very large quantity of bedload and suspended sediment load because they are generally located in the vicinity of highly erosive hillslopes. Consequently, these rivers play an important role because they supply and control the sediment load of the entire downstream fluvial ...

  19. Meso-Scale Damage Simulation of 3D Braided Composites under Quasi-Static Axial Tension

    Science.gov (United States)

    Zhang, Chao; Mao, Chunjian; Zhou, Yexin

    2017-01-01

    The microstructure of 3D braided composites is composed of three phases: braiding yarn, matrix and interface. In this paper, a representative unit-cell (RUC) model including these three phases is established. Coupling with the periodical boundary condition, the damage behavior of 3D braided composites under quasi-static axial tension is simulated by using finite element method based on this RUC model. An anisotropic damage model based on Murakami damage theory is proposed to predict the damage evolution of yarns and matrix; a damage-friction combination interface constitutive model is adopted to predict the interface debonding behavior. A user material subroutine (VUMAT) involving these damage models is developed and implemented in the finite element software ABAQUS/Explicit. The whole process of damage evolution of 3D braided composites under quasi-static axial tension with typical braiding angles is simulated, and the damage mechanisms are revealed in detail in the simulation process. The tensile strength properties of the braided composites are predicted from the calculated stress-strain curves. Numerical results agree with the available experiment data and thus validates the proposed damage analysis model. The effects of certain material parameters on the predicted stress-strain responses are also discussed by numerical parameter study.

  20. Evaluation of Braided Stiffener Concepts for Transport Aircraft Wing Structure Applications

    Science.gov (United States)

    Deaton, Jerry W.; Dexter, H. Benson (Editor); Markus, Alan; Rohwer, Kim

    1995-01-01

    Braided composite materials have potential for application in aircraft structures. Stiffeners, wing spars, floor beams, and fuselage frames are examples where braided composites could find application if cost effective processing and damage requirements are met. Braiding is an automated process for obtaining near-net shape preforms for fabrication of components for structural applications. Previous test results on braided composite materials obtained at NASA Langley indicate that damage tolerance requirements can be met for some applications. In addition, the braiding industry is taking steps to increase the material through-put to be more competitive with other preform fabrication processes. Data are presented on the compressive behavior of three braided stiffener preform fabric constructions as determined from individual stiffener crippling test and three stiffener wide panel tests. Stiffener and panel fabrication are described and compression data presented for specimens tested with and without impact damage. In addition, data are also presented on the compressive behavior of the stitched stiffener preform construction currently being used by McDonnell Douglas Aerospace in the NASA ACT wing development program.

  1. Meso-Scale Damage Simulation of 3D Braided Composites under Quasi-Static Axial Tension

    Science.gov (United States)

    Zhang, Chao; Mao, Chunjian; Zhou, Yexin

    2017-10-01

    The microstructure of 3D braided composites is composed of three phases: braiding yarn, matrix and interface. In this paper, a representative unit-cell (RUC) model including these three phases is established. Coupling with the periodical boundary condition, the damage behavior of 3D braided composites under quasi-static axial tension is simulated by using finite element method based on this RUC model. An anisotropic damage model based on Murakami damage theory is proposed to predict the damage evolution of yarns and matrix; a damage-friction combination interface constitutive model is adopted to predict the interface debonding behavior. A user material subroutine (VUMAT) involving these damage models is developed and implemented in the finite element software ABAQUS/Explicit. The whole process of damage evolution of 3D braided composites under quasi-static axial tension with typical braiding angles is simulated, and the damage mechanisms are revealed in detail in the simulation process. The tensile strength properties of the braided composites are predicted from the calculated stress-strain curves. Numerical results agree with the available experiment data and thus validates the proposed damage analysis model. The effects of certain material parameters on the predicted stress-strain responses are also discussed by numerical parameter study.

  2. Theory of equilibria of elastic braids with applications to DNA supercoiling

    Science.gov (United States)

    van der Heijden, Gert; Starostin, Eugene

    2014-03-01

    Motivated by supercoiling of DNA and other filamentous structures, we formulate a new theory for equilibria of 2-braids, i.e., structures formed by two elastic rods winding around each other in continuous contact and subject to a local interstrand interaction. Unlike in previous work no assumption is made on the shape of the contact curve. Rather, this shape is solved for. The theory is developed in terms of a moving frame of directors attached to one of the strands with one of the directors pointing to the position of the other strand. The constant-distance constraint is automatically satisfied by the introduction of what we call braid strains. The price we pay is that the potential energy involves arclength derivatives of these strains, thus giving rise to a second-order variational problem. The Euler-Lagrange equations for this problem give balance equations for the overall braid force and moment referred to the moving frame as well as differential equations that can be interpreted as effective constitutive relations encoding the effect that the second strand has on the first as the braid deforms under the action of end loads. Both open braid and closed braid solutions (links and knots) are computed and current applications to DNA supercoiling are discussed. Research supported by EPSRC and HFSP.

  3. Locality of entangled polymer dynamics

    Science.gov (United States)

    Tsang, Chi Hang Boyce; Jiang, Lingxiang; Granick, Steve

    2014-03-01

    A combination of sparse and full fluorescence labeling of entangled actin solutions (filaments about 15 μm long at 1 mg/ml concentration) allowed us to probe both filament-scale polymer dynamics and effectively monomer dynamics. On the filament scale, the reptation tube idea of classical polymer physics works well. However, on a local scale comparable to mesh size, local tube width fluctuation becomes important. For the first time, the dependence of longitudinal diffusion on local tube width was quantified.

  4. Braided Multi-Electrode Probes (BMEPs) for Neural Interfaces

    Science.gov (United States)

    Kim, Tae Gyo

    Although clinical use of invasive neural interfaces is very limited, due to safety and reliability concerns, the potential benefits of their use in brain machine interfaces (BMIs) seem promising and so they have been widely used in the research field. Microelectrodes as invasive neural interfaces are the core tool to record neural activities and their failure is a critical issue for BMI systems. Possible sources of this failure are neural tissue motions and their interactions with stiff electrode arrays or probes fixed to the skull. To overcome these tissue motion problems, we have developed novel braided multi-electrode probes (BMEPs). By interweaving ultra-fine wires into a tubular braid structure, we obtained a highly flexible multi-electrode probe. In this thesis we described BMEP designs and how to fabricate BMEPs, and explore experiments to show the advantages of BMEPs through a mechanical compliance comparison and a chronic immunohistological comparison with single 50microm nichrome wires used as a reference electrode type. Results from the mechanical compliance test showed that the bodies of BMEPs have 4 to 21 times higher compliance than the single 50microm wire and the tethers of BMEPs were 6 to 96 times higher compliance, depending on combinations of the wire size (9.6microm or 12.7microm), the wire numbers (12 or 24), and the length of tether (3, 5 or 10 mm). Results from the immunohistological comparison showed that both BMEPs and 50microm wires anchored to the skull caused stronger tissue reactions than unanchored BMEPs and 50microm wires, and 50microm wires caused stronger tissue reactions than BMEPs. In in-vivo tests with BMEPs, we succeeded in chronic recordings from the spinal cord of freely jumping frogs and in acute recordings from the spinal cord of decerebrate rats during air stepping which was evoked by mesencephalic locomotor region (MLR) stimulation. This technology may provide a stable and reliable neural interface to spinal cord

  5. Turkana Grits - a Cretaceous braided alluvial system in northern Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Handford, C.R.

    1987-05-01

    Rather spotty but excellent exposures of the Cretaceous-age Turkana Grits occur near the western shore of Lake Turkana, northern Kenya. These very coarse to pebbly arkosic sandstones and sandy conglomerates were derived from and rest unconformably upon Precambrian metamorphic basement; they are overlain by late Tertiary basaltic flows that comprise much of the volcanics in the East African Rift Zone. The formation ranges up to 2000 ft thick in the Laburr Range. Several outcrops contain sauropod, crocodile, and tortoise remains as well as abundant trunks of petrified wood (Dryoxylon). Five major facies make up the Turkana Grits and record a major episode of continental fluvial deposition in basins flanked by Precambrian basement. Facies 1 is crudely stratified, cobble and boulder conglomerate (clast-supported); Facies 2 is crudely stratified pebble-cobble conglomerate and pebbly sandstone; Facies 3 is trough cross-bedded, very coarse sandstones containing fossils wood and vertebrate remains; Facies 4 is crudely stratified to massive sandstones with ironstone nodules; and Facies 5 is red, purple, and gray mudstone and mud shale with carbonate nodules. Facies 1 through 3 record deposition in proximal to medial braided-stream channel, longitudinal bar and dune complexes. Facies 4 is a lowland, hydromorphic paleosol, and Facies 5 represents overbank and abandoned channel-fill sedimentation in an alluvial plain.

  6. Emulating Majorana fermions and their braiding by Ising spin chains

    Science.gov (United States)

    Backens, Stefan; Shnirman, Alexander; Makhlin, Yuriy; Gefen, Yuval; Mooij, Johan E.; Schön, Gerd

    2017-11-01

    We analyze the control of Majorana zero-energy states by mapping the fermionic system onto a chain of Ising spins. Although the topological protection is lost for the Ising system, the mapping provides additional insight into the nature of the quantum states. By controlling the local magnetic field, one can separate the Ising chain into ferromagnetic and paramagnetic phases, corresponding to topological and nontopological sections of the fermionic system. In this paper we propose (topologically nonprotected) protocols performing the braiding operation, and in fact also more general rotations. We first consider a T -junction geometry, but we also propose a protocol for a purely one-dimensional (1D) system. Both setups rely on an extra spin-1/2 coupler. By including the extra spin in the T -junction geometry, we overcome limitations due to the 1D character of the Jordan-Wigner transformation. In the 1D geometry the coupler, which controls one of the Ising links, should be manipulated once the ferromagnetic (topological) section of the chain is moved far away. We also propose experimental implementations of our scheme. One is based on a chain of flux qubits which allows for all needed control fields. We also describe how to translate our scheme for the 1D setup to a chain of superconducting wires hosting each a pair of Majorana edge states.

  7. Development and implementation of an automatic integration system for fibre optic sensors in the braiding process with the objective of online-monitoring of composite structures

    Science.gov (United States)

    Hufenbach, W.; Gude, M.; Czulak, A.; Kretschmann, Martin

    2014-04-01

    Increasing economic, political and ecological pressure leads to steadily rising percentage of modern processing and manufacturing processes for fibre reinforced polymers in industrial batch production. Component weights beneath a level achievable by classic construction materials, which lead to a reduced energy and cost balance during product lifetime, justify the higher fabrication costs. However, complex quality control and failure prediction slow down the substitution by composite materials. High-resolution fibre-optic sensors (FOS), due their low diameter, high measuring point density and simple handling, show a high applicability potential for an automated sensor-integration in manufacturing processes, and therefore the online monitoring of composite products manufactured in industrial scale. Integrated sensors can be used to monitor manufacturing processes, part tests as well as the component structure during product life cycle, which simplifies allows quality control during production and the optimization of single manufacturing processes.[1;2] Furthermore, detailed failure analyses lead to a enhanced understanding of failure processes appearing in composite materials. This leads to a lower wastrel number and products of a higher value and longer product life cycle, whereby costs, material and energy are saved. This work shows an automation approach for FOS-integration in the braiding process. For that purpose a braiding wheel has been supplemented with an appliance for automatic sensor application, which has been used to manufacture preforms of high-pressure composite vessels with FOS-networks integrated between the fibre layers. All following manufacturing processes (vacuum infiltration, curing) and component tests (quasi-static pressure test, programmed delamination) were monitored with the help of the integrated sensor networks. Keywords: SHM, high-pressure composite vessel, braiding, automated sensor integration, pressure test, quality control, optic

  8. Feeding Tubes

    Science.gov (United States)

    ... feeding therapies have been exhausted. Please review product brand and method of placement carefully with your physician ... Total Parenteral Nutrition. Resources: Oley Foundation Feeding Tube Awareness Foundation Children’s Medical Nutrition Alliance APFED’s Educational Webinar ...

  9. Finite Element Model for Failure Study of Two-Dimensional Triaxially Braided Composite

    Science.gov (United States)

    Li, Xuetao; Binienda, Wieslaw K.; Goldberg, Robert K.

    2010-01-01

    A new three-dimensional finite element model of two-dimensional triaxially braided composites is presented in this paper. This meso-scale modeling technique is used to examine and predict the deformation and damage observed in tests of straight sided specimens. A unit cell based approach is used to take into account the braiding architecture as well as the mechanical properties of the fiber tows, the matrix and the fiber tow-matrix interface. A 0 deg / plus or minus 60 deg. braiding configuration has been investigated by conducting static finite element analyses. Failure initiation and progressive degradation has been simulated in the fiber tows by use of the Hashin failure criteria and a damage evolution law. The fiber tow-matrix interface was modeled by using a cohesive zone approach to capture any fiber-matrix debonding. By comparing the analytical results to those obtained experimentally, the applicability of the developed model was assessed and the failure process was investigated.

  10. Mechanical Performance and Parameter Sensitivity Analysis of 3D Braided Composites Joints

    Directory of Open Access Journals (Sweden)

    Yue Wu

    2014-01-01

    Full Text Available 3D braided composite joints are the important components in CFRP truss, which have significant influence on the reliability and lightweight of structures. To investigate the mechanical performance of 3D braided composite joints, a numerical method based on the microscopic mechanics is put forward, the modeling technologies, including the material constants selection, element type, grid size, and the boundary conditions, are discussed in detail. Secondly, a method for determination of ultimate bearing capacity is established, which can consider the strength failure. Finally, the effect of load parameters, geometric parameters, and process parameters on the ultimate bearing capacity of joints is analyzed by the global sensitivity analysis method. The results show that the main pipe diameter thickness ratio γ, the main pipe diameter D, and the braided angle α are sensitive to the ultimate bearing capacity N.

  11. Bundles of spider silk, braided into sutures, resist basic cyclic tests: potential use for flexor tendon repair.

    Directory of Open Access Journals (Sweden)

    Kathleen Hennecke

    Full Text Available Repair success for injuries to the flexor tendon in the hand is often limited by the in vivo behaviour of the suture used for repair. Common problems associated with the choice of suture material include increased risk of infection, foreign body reactions, and inappropriate mechanical responses, particularly decreases in mechanical properties over time. Improved suture materials are therefore needed. As high-performance materials with excellent tensile strength, spider silk fibres are an extremely promising candidate for use in surgical sutures. However, the mechanical behaviour of sutures comprised of individual silk fibres braided together has not been thoroughly investigated. In the present study, we characterise the maximum tensile strength, stress, strain, elastic modulus, and fatigue response of silk sutures produced using different braiding methods to investigate the influence of braiding on the tensile properties of the sutures. The mechanical properties of conventional surgical sutures are also characterised to assess whether silk offers any advantages over conventional suture materials. The results demonstrate that braiding single spider silk fibres together produces strong sutures with excellent fatigue behaviour; the braided silk sutures exhibited tensile strengths comparable to those of conventional sutures and no loss of strength over 1000 fatigue cycles. In addition, the braiding technique had a significant influence on the tensile properties of the braided silk sutures. These results suggest that braided spider silk could be suitable for use as sutures in flexor tendon repair, providing similar tensile behaviour and improved fatigue properties compared with conventional suture materials.

  12. Development of braided rope seals for hypersonic engine applications. Part 2: Flow modeling

    Science.gov (United States)

    Mutharasan, Rajakkannu; Steinetz, Bruce M.; Tao, Xiaoming; Ko, Frank

    1991-01-01

    Two models based on the Kozeny-Carmen equation were developed to analyze the fluid flow through a new class of braided rope seals under development for advanced hypersonic engines. A hybrid seal geometry consisting of a braided sleeve and a substantial amount of longitudinal fibers with high packing density was selected for development based on its low leakage rates. The models developed allow prediction of the gas leakage rate as a function of fiber diameter, fiber packing density, gas properties, and pressure drop across the seal.

  13. Development of braided rope seals for hypersonic engine applications. II - Flow modeling

    Science.gov (United States)

    Mutharasan, Rajakkannu; Tao, Xiaoming; Ko, Frank; Steinetz, Bruce M.

    1991-01-01

    Two models based on the Kozeny-Carmen equation were developed to analyze the fluid flow through a new class of braided rope seals under development for advanced hypersonic engines. A hybrid seal geometry consisting of a braided sleeve and a substantial amount of longitudinal fibers with high packing density was selected for development based on its low leakage rates. The models developed allow prediction of the gas leakage rate as a function of fiber diameter, fiber packing density, gas properties, and pressure drop across the seal.

  14. A hybrid surface modification method on copper wire braids for enhancing thermal performance of ultra-thin heat pipes

    Science.gov (United States)

    Sheng, W. K.; Lin, H. T.; Wu, C. H.; Kuo, L. S.; Chen, P. H.

    2017-02-01

    Copper is the most widely used material in heat pipe manufacturing. Since the capability of wick structures inside a heat pipe will dominate its thermal performance, in this study, we introduce a hybrid surface modification method on the copper wire braids being inserted as wick structure into an ultra-thin heat pipe. The hybrid method is the combination of a chemical-oxidation-based method and a sol-gel method with nanoparticles being dip-coated onto the braid. The experimental data show that braids under hybrid treatment perform higher water rising speed than the oxidized braids while owning higher water net weight than those braids being only dip-coated with nanoparticle.

  15. Effect of Microscopic Damage Events on Static and Ballistic Impact Strength of Triaxial Braid Composites

    Science.gov (United States)

    Littell, Justin D.; Binienda, Wieslaw K.; Arnold, William A.; Roberts, Gary D.; Goldberg, Robert K.

    2010-01-01

    The reliability of impact simulations for aircraft components made with triaxial-braided carbon-fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Methods to characterize the material properties used in the analytical models from a systematically obtained set of test data are also lacking. A macroscopic finite element based analytical model to analyze the impact response of these materials has been developed. The stiffness and strength properties utilized in the material model are obtained from a set of quasi-static in-plane tension, compression and shear coupon level tests. Full-field optical strain measurement techniques are applied in the testing, and the results are used to help in characterizing the model. The unit cell of the braided composite is modeled as a series of shell elements, where each element is modeled as a laminated composite. The braided architecture can thus be approximated within the analytical model. The transient dynamic finite element code LS-DYNA is utilized to conduct the finite element simulations, and an internal LS-DYNA constitutive model is utilized in the analysis. Methods to obtain the stiffness and strength properties required by the constitutive model from the available test data are developed. Simulations of quasi-static coupon tests and impact tests of a represented braided composite are conducted. Overall, the developed method shows promise, but improvements that are needed in test and analysis methods for better predictive capability are examined.

  16. The Processing Design of Jute Spun Yarn/PLA Braided Composite by Pultrusion Molding

    Directory of Open Access Journals (Sweden)

    Anin Memon

    2013-01-01

    Full Text Available Prevalently, the light has been shed on the green composite from the viewpoint of environmental protection. Jute fibers are natural fibers superior due to light weight, low cost, and being environmentally friendly corresponding to the green composite materials. Meticulously, fibers of polylactic acid (PLA thermoplastic biopolymer were used as the resin fibers. In this study, the fabrication of tubular jute spun yarn/PLA braided composite by pultrusion molding was presented. The intermediate materials were prepared by commingled technique. The braiding technique manufactured preform which had jute fiber diagonally oriented at certain angles with the glass fiber inserted into the braiding yarns along the longitudinal direction. The braided preforms were pulled through a heated die where the consolidation flow took place due to reduced matrix viscosity and pressure. The pultrusion experiments were done with jute/PLA commingled yarns and combined with glass fiber yarns to fabricate the tubular composite. Impregnation quality was evaluated by microscope observation of the pultruded cross-sections. The flexural mechanical properties of the pultruded were measured by four-point bending test.

  17. Design and Testing of Braided Composite Fan Case Materials and Components

    Science.gov (United States)

    Roberts, Gary D.; Pereira, J. Michael; Braley, Michael S.; Arnold, William a.; Dorer, James D.; Watson, William R/.

    2009-01-01

    Triaxial braid composite materials are beginning to be used in fan cases for commercial gas turbine engines. The primary benefit for the use of composite materials is reduced weight and the associated reduction in fuel consumption. However, there are also cost benefits in some applications. This paper presents a description of the braided composite materials and discusses aspects of the braiding process that can be utilized for efficient fabrication of composite cases. The paper also presents an approach that was developed for evaluating the braided composite materials and composite fan cases in a ballistic impact laboratory. Impact of composite panels with a soft projectile is used for materials evaluation. Impact of composite fan cases with fan blades or blade-like projectiles is used to evaluate containment capability. A post-impact structural load test is used to evaluate the capability of the impacted fan case to survive dynamic loads during engine spool down. Validation of these new test methods is demonstrated by comparison with results of engine blade-out tests.

  18. Survival of flexible, braided, bonded stainless steel lingual retainers : a historic cohort study

    NARCIS (Netherlands)

    Foek, D. J. Lie Sam; Ozcan, M.; Verkerke, G. J.; Sandham, John; Dijkstra, P. U.

    The objectives of this study were to retrospectively evaluate the clinical survival rate of flexible, braided, rectangular bonded stainless steel lingual retainers, and to investigate the influence of gender, age of the patient, and operator experience on survival after orthodontic treatment at the

  19. A Modeling Technique and Representation of Failure in the Analysis of Triaxial Braided Carbon Fiber Composites

    Science.gov (United States)

    Littell, Justin D.; Binienda, Wieslaw K.; Goldberg, Robert K.; Roberts, Gary D.

    2008-01-01

    Quasi-static tests have been performed on triaxially braided carbon fiber composite materials with large unit cell sizes. The effects of different fibers and matrix materials on the failure mode were investigated. Simulations of the tests have been performed using the transient dynamic finite element code, LS-DYNA. However, the wide range of failure modes observed for the triaxial braided carbon fiber composites during tests could not be simulated using composite material models currently available within LS-DYNA. A macroscopic approach has been developed that provides better simulation of the material response in these materials. This approach uses full-field optical measurement techniques to measure local failures during quasi-static testing. Information from these experiments is then used along with the current material models available in LS-DYNA to simulate the influence of the braided architecture on the failure process. This method uses two-dimensional shell elements with integration points through the thickness of the elements to represent the different layers of braid along with a new analytical method for the import of material stiffness and failure data directly. The present method is being used to examine the effect of material properties on the failure process. The experimental approaches used to obtain the required data will be described, and preliminary results of the numerical analysis will be presented.

  20. Flow patterns and critical criteria of thermally stratified shear flow in braided rivers

    Directory of Open Access Journals (Sweden)

    Li Gu

    2017-07-01

    Full Text Available Flow characteristics of thermally stratified shear flow in braided rivers are particularly complicated and poorly understood. In this study, a series of typical flow patterns was examined and their critical criteria were determined. Four flow patterns were identified: mixed, locally unstable, continuously stratified, and two-layer flow. Temperature distributions of the four types of flow patterns were analyzed and compared. The critical Froude numbers for unstable flow, FDcr1, and stable flow, FDcr2, were determined to be 6 and 1, respectively, and comparison of FDcr1 and FDcr2 to the peak Froude numbers, FD1 at the outer bank and FD2 at the inner bank along the anabranch, allowed the flow patterns to be assessed. Then, a discriminant based on initial Jeffreys-Keulegan stability parameters was established to distinguish the flow stages from two-layer flow to completely mixed flow. It is indicated that the three critical Jeffreys-Keulegan parameters increased with the diversion angle of braided rivers. Results also show that, compared to the stratified flow in straight and curved channels, it was more difficult for braided stratified flow to maintain as two-layer flow, and it more easily became mixed flow. Consequently, empirical expressions for stability criteria of the thermally stratified shear flow in braided rivers are presented.

  1. Effect of sampling time in the laboratory investigation of braided rivers

    Science.gov (United States)

    Vesipa, R.; Camporeale, C.; Ridolfi, L.

    2017-06-01

    We focus on the measurement of the bed-elevation of braided networks in flume experiments. In particular, the effect of the survey frequency on the measurement accuracy is studied. To this aim, an innovative measurement system is adopted. It consists of a laser-ultrasonic sensor and can survey the bed-elevation under flowing water. This measurement system was used to profile a flume transect with a frequency of 4 min, without stopping the water discharge. By this technique, the topography of a single transect was continuously acquired during the evolution of a braided river model. Twelve braided rivers generated with different experimental conditions were studied. The main results are (i) there exists a threshold survey frequency (4-8 min in our analysis) which guarantees that the morphological evolution of the braiding channels is fully measured; (ii) if this threshold frequency of survey is exceeded, significant errors occur in the balance of the eroded/deposited sediments and in the evaluation of the bed-elevation dynamics; and (iii) these errors depend on the river stream power.

  2. Layer Construction of 3D Topological States and String Braiding Statistics

    Directory of Open Access Journals (Sweden)

    Chao-Ming Jian

    2014-12-01

    Full Text Available While the topological order in two dimensions has been studied extensively since the discovery of the integer and fractional quantum Hall systems, topological states in three spatial dimensions are much less understood. In this paper, we propose a general formalism for constructing a large class of three-dimensional topological states by stacking layers of 2D topological states and introducing coupling between them. Using this construction, different types of topological states can be obtained, including those with only surface topological order and no bulk topological quasiparticles, and those with topological order both in the bulk and at the surface. For both classes of states, we study its generic properties and present several explicit examples. As an interesting consequence of this construction, we obtain example systems with nontrivial braiding statistics between string excitations. In addition to studying the string-string braiding in the example system, we propose a topological field-theory description for the layer-constructed systems, which captures not only the string-particle braiding statistics but also the string-string braiding statistics when the coupling is twisted. Last, we provide a proof of a general identity for Abelian string statistics and discuss an example system with non-Abelian strings.

  3. Sediment heterogeneity and mobility in the morphodynamic modelling of gravel-bed braided rivers

    Science.gov (United States)

    Singh, Umesh; Crosato, Alessandra; Giri, Sanjay; Hicks, Murray

    2017-06-01

    The effects of sediment heterogeneity and sediment mobility on the morphology of braided rivers are still poorly studied, especially when the partial sediment mobility occurs. Nevertheless, increasing the bed sediment heterogeneity by coarse sediment supply is becoming a common practice in river restoration projects and habitat improvement all over the world. This research provides a step forward in the identification of the effects of sediment sorting on the evolution of sediment bars and braiding geometry of gravel-bed rivers. A two-dimensional morphodynamic model was used to simulate the long-term developments of a hypothetical braided system with discharge regime and morphodynamic parameters derived from the Waimakariri River, New Zealand. Several scenarios, differing in bed sediment heterogeneity and sediment mobility, were considered. The results agree with the tendencies already identified in linear analyses and experimental studies, showing that a larger sediment heterogeneity increases the braiding indes and reduces the bars length and height. The analyses allowed identifying the applicability limits of uniform sediment and variable discharge modelling approaches.

  4. Ear Tubes

    Science.gov (United States)

    ... of the ear drum or eustachian tube, Down Syndrome, cleft palate, and barotrauma (injury to the middle ear caused by a reduction of air pressure, ... specialist) may be warranted if you or your child has experienced repeated ... fluid in the middle ear, barotrauma, or have an anatomic abnormality that ...

  5. Effect of open hole on tensile failure properties of 2D triaxial braided textile composites and tape equivalents

    Science.gov (United States)

    Norman, Timothy L.; Anglin, Colin; Gaskin, David; Patrick, Mike

    1995-01-01

    The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to triaxial braided textile composite materials. Four fiber architectures were considered with different combinations of braid angle, longitudinal and braider yam size, and percentage of longitudinal yarns. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yams cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Longitudinal yarn splitting occurred in three of four architectures that were longitudinally fiber dominated. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch stress between measured and predicted stress were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.

  6. Is braiding an endangered river species? Converging morphological trajectories from multiple geographic contexts.

    Science.gov (United States)

    Stecca, Guglielmo; Zolezzi, Guido; Surian, Nicola; Hicks, Murray

    2017-04-01

    Observations of morphological change in braided rivers, comprising narrowing of the total and active braidplain, degradation (at least in some reaches), increase in vegetation cover, and reduction of braiding complexity towards a transitional style, have been increasingly reported worldwide in the last decades. Most of the available literature concerns rivers in Europe, with particular reference to the Alpine and pre-Alpine region (e.g., Italy, France, Austria, Switzerland). This abundance reflects the magnitude of changes in Europe, where most of braided reaches have been heavily impacted. However, contributions from other regions of Europe (e.g., the Polish Carpathians, Spain, Scotland, Corsica) and of the Earth (e.g., the South Island of New Zealand) document similar stories. These morphodynamic changes have been related to the alteration of the fundamental physical processes in braided rivers driven by the flow and sediment supply regimes, due to anthropogenic changes in constraints and controls. Multiple and context-specific sources of impact on these controls have been identified, including damming, landuse change, gravel mining, torrent control works, channelisation, introduction of alien vegetation. Here, we focus on a comparative analysis of the relatively recent (multi-decadal) evolution of braided rivers located in different geographic regions on the Earth, with particular reference to the Waitaki (New Zealand), Piave (Italy) and Dunajec (Poland) rivers. These rivers display similar morphological trajectories, which nonetheless result from very different paths of causation, i.e., from different management causes and different alteration of physical processes. We focus on the role of different physical and human geographic contexts as drivers of the river evolution, highlighting the relations between the observed trajectories and the local conditions and characteristics. We discuss the relative role of dam construction and operation in contributing to the

  7. Assessing the Adequacy of Absorbable Braided Suture for Laparoscopic High Ligation in Rabbits.

    Science.gov (United States)

    Bruns, Nicholas E; Glenn, Ian C; Craner, Domenic R; McNinch, Neil L; Schomisch, Steve J; Ponsky, Todd A

    2017-07-01

    Our previous work demonstrated that intentional peritoneal injury reduces the incidence of recurrence of a patent processus vaginalis even after removal of the suture. Therefore, the necessity of permanent suture has been brought into question because of the risk of suture granuloma formation. The purpose of this study was to evaluate the efficacy of absorbable, braided versus permanent, braided suture in a rabbit survival model of laparoscopic percutaneous ligation of the processus vaginalis with intentional peritoneal injury. Eighteen New Zealand White rabbits underwent bilateral subcutaneous endoscopically assisted ligation (SEAL) of the internal ring. Before SEAL, peritoneal injury was caused with endoscopic shears. Each animal was randomized to receive absorbable braided suture on one side and permanent braided suture on the contralateral side. The rabbits were survived for 8 weeks to allow for complete hydrolysis of the absorbable suture. Necropsy was performed during which the integrity of the repair was assessed with insufflation of carbon dioxide up to 30 mm Hg. McNemar's test for paired data was performed for statistical analysis. Seventeen rabbits survived 8 weeks. One rabbit died in the early postoperative period because of urinary tract obstruction. After insufflation, four (24%) recurrences were present in the absorbable group and two (12%) recurrences were present in the permanent group. This difference was not statistically significant (P = .50). Both rabbits with a recurrence on the side with permanent suture also had a recurrence with absorbable suture on the contralateral side. In all rabbits, the permanent suture was identified, whereas there was no visual evidence of absorbable suture. A trend toward a higher recurrence rate with the use of absorbable braided suture was present, although, in this study, the finding was not statistically significant. Caution should be used when considering implementation of absorbable suture for

  8. Neutron tubes

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui; Reijonen, Jani

    2008-03-11

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  9. photomultiplier tube

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  10. photomultiplier tubes

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  11. A single width-discharge regime relationship for individual threads of braided and meandering rivers from the Himalayan Foreland

    OpenAIRE

    Gaurav, Kumar; S Tandon; Devauchelle, Olivier; Sinha, Rajiv; Métivier, François

    2017-01-01

    International audience; We explore the existence of a single width-discharge regime relation for allu-vial rivers of braided and meandering patterns. The study relies on the field measurement of a channel's cross section geometry (width, depth), discharge, and grain size of 98 individual threads of braided and meandering rivers from the Ganga-Brahmaputra plains of the Himalayan Foreland. Using this data set, we show that, irrespective of the diverse climatic and geologic setting along the str...

  12. Finite Element Modeling of Thermal Cycling Induced Microcracking in Carbon/Epoxy Triaxial Braided Composites

    Science.gov (United States)

    Zhang, Chao; Binienda, Wieslaw K.; Morscher, Gregory; Martin, Richard E.

    2012-01-01

    The microcrack distribution and mass change in PR520/T700s and 3502/T700s carbon/epoxy braided composites exposed to thermal cycling was evaluated experimentally. Acoustic emission was utilized to record the crack initiation and propagation under cyclic thermal loading between -55 C and 120 C. Transverse microcrack morphology was investigated using X-ray Computed Tomography. Different performance of two kinds of composites was discovered and analyzed. Based on the observations of microcrack formation, a meso-mechanical finite element model was developed to obtain the resultant mechanical properties. The simulation results exhibited a decrease in strength and stiffness with increasing crack density. Strength and stiffness reduction versus crack densities in different orientations were compared. The changes of global mechanical behavior in both axial and transverse loading conditions were studied. Keywords: Thermal cycles; Microcrack; Finite Element Model; Braided Composite

  13. ℓ1-norm and entanglement in screening out braiding from Yang-Baxter equation associated with Z3 parafermion

    Science.gov (United States)

    Yu, Li-Wei; Ge, Mo-Lin

    2017-03-01

    The relationships between quantum entangled states and braid matrices have been well studied in recent years. However, most of the results are based on qubits. In this paper, we investigate the applications of 2-qutrit entanglement in the braiding associated with Z3 parafermion. The 2-qutrit entangled state | Ψ (θ) >, generated by the action of the localized unitary solution R ˘ (θ) of YBE on 2-qutrit natural basis, achieves its maximal ℓ1-norm and maximal von Neumann entropy simultaneously at θ = π / 3. Meanwhile, at θ = π / 3, the solutions of YBE reduces braid matrices, which implies the role of ℓ1-norm and entropy plays in determining real physical quantities. On the other hand, we give a new realization of 4-anyon topological basis by qutrit entangled states, then the 9 × 9 localized braid representation in 4-qutrit tensor product space (C3) ⊗ 4 is reduced to Jones representation of braiding in the 4-anyon topological basis. Hence, we conclude that the entangled states are powerful tools in analysing the characteristics of braiding and R ˘ -matrix.

  14. A Tube Model of Rubber Elasticity

    OpenAIRE

    Kutter, S.; Terentjev, E. M.

    2001-01-01

    Polymer entanglements lead to complicated topological constraints and interactions between neighbouring chains in a dense solution or melt. Entanglements can be treated in a mean field approach, within the famous reptation model, since they effectively confine each individual chain in a tube-like geometry. In polymer networks, due to crosslinks preventing the reptation constraint release, entanglements acquire a different topological meaning and have a much stronger effect on the resulting me...

  15. Quantitative physical and handling characteristics of novel antibacterial braided silk suture materials.

    Science.gov (United States)

    Chen, Xiaojie; Hou, Dandan; Tang, Xiaoqi; Wang, Lu

    2015-10-01

    Surgical braided silk sutures have been widely used because these materials exhibit good handling characteristics, ease of use, and ideal knot security. However, surgical silk sutures likely cause surgical site infections because these sutures are composed of natural protein materials with a braided structure. As such, antibacterial silk sutures for clinical wound closure should be developed. Braided silk suture could be treated and modified with antibacterial agent, provided that excellent physical and handling characteristics of this material should maximize maintained. This study aimed to quantitatively investigate the effect of antibacterial treatment with different parameters on physical and handling characteristics of novel antibacterial braided silk sutures. Physical and handling characteristics, including appearance, knot-pull tensile strength, pullout friction resistance, tissue drag friction resistance, and bending stiffness, were evaluated. After physical and handling tests were conducted, images showed morphological characteristics were obtained and evaluated to investigate the relationship between antibacterial treatment and physical and handling properties. Results showed that suture diameter increased and reached the nearest thick size specification; knot-pull tensile strength decreased but remained higher than the standard value by at least 40.73%. Fracture asynchronism during knot-pull tensile strength test suggested that the fineness ratio of shell and core strands may enhance knot-pull tensile strength. Static and dynamic frictions of suture-to-suture friction behavior were slightly affected by antibacterial treatment, and changed to less than 16.07% and 32.77%, respectively. Suture-to-tissue friction and bending stiffness increased by approximately 50%; the bending stiffness of the proposed suture remained efficient compared with that of synthetic sutures. Therefore, good physical and handling characteristics can be maintained by selecting

  16. Stochastic particle acceleration at shocks in the presence of braided magnetic fields

    OpenAIRE

    Kirk, J. G.; Duffy, P.; Gallant, Y. A.

    1996-01-01

    The theory of diffusive acceleration of energetic particles at shock fronts assumes charged particles undergo spatial diffusion in a uniform magnetic field. If, however, the magnetic field is not uniform, but has a stochastic or braided structure, the transport of charged particles across the average direction of the field is more complicated. Assuming quasi-linear behaviour of the field lines, the particles undergo sub-diffusion on short time scales. We derive the propagator for such motion,...

  17. Vortex pinning by the point potential in topological superconductors: A scheme for braiding Majorana bound states

    Science.gov (United States)

    Wu, Hai-Dan; Zhou, Tao

    2017-11-01

    We propose theoretically an effective scheme for braiding Majorana bound states by manipulating the point potential. The vortex pinning effect is carefully elucidated. This effect can be used to control the vortices and Majorana bound states in topological superconductors. The exchange of two vortices induced by moving the potentials is simulated numerically. The zero-energy state in the vortex core is robust with respect to the strength of the potential. The Majorana bound states in a pinned vortex are identified numerically.

  18. GoldenBraid: an iterative cloning system for standardized assembly of reusable genetic modules.

    Directory of Open Access Journals (Sweden)

    Alejandro Sarrion-Perdigones

    Full Text Available Synthetic Biology requires efficient and versatile DNA assembly systems to facilitate the building of new genetic modules/pathways from basic DNA parts in a standardized way. Here we present GoldenBraid (GB, a standardized assembly system based on type IIS restriction enzymes that allows the indefinite growth of reusable gene modules made of standardized DNA pieces. The GB system consists of a set of four destination plasmids (pDGBs designed to incorporate multipartite assemblies made of standard DNA parts and to combine them binarily to build increasingly complex multigene constructs. The relative position of type IIS restriction sites inside pDGB vectors introduces a double loop ("braid" topology in the cloning strategy that allows the indefinite growth of composite parts through the succession of iterative assembling steps, while the overall simplicity of the system is maintained. We propose the use of GoldenBraid as an assembly standard for Plant Synthetic Biology. For this purpose we have GB-adapted a set of binary plasmids for A. tumefaciens-mediated plant transformation. Fast GB-engineering of several multigene T-DNAs, including two alternative modules made of five reusable devices each, and comprising a total of 19 basic parts are also described.

  19. From Constraints to Resolution Rules Part II : chains, braids, confluence and T&E

    Science.gov (United States)

    Berthier, Denis

    In this Part II, we apply the general theory developed in Part I to a detailed analysis of the Constraint Satisfaction Problem (CSP). We show how specific types of resolution rules can be defined. In particular, we introduce the general notions of a chain and a braid. As in Part I, these notions are illustrated in detail with the Sudoku example - a problem known to be NP-complete and which is therefore typical of a broad class of hard problems. For Sudoku, we also show how far one can go in "approximating" a CSP with a resolution theory and we give an empirical statistical analysis of how the various puzzles, corresponding to different sets of entries, can be classified along a natural scale of complexity. For any CSP, we also prove the confluence property of some Resolution Theories based on braids and we show how it can be used to define different resolution strategies. Finally, we prove that, in any CSP, braids have the same solving capacity as Trial-and-Error (T&E) with no guessing and we comment this result in the Sudoku case.

  20. Metrics for assessing the performance of morphodynamic models of braided rivers at event and reach scales

    Science.gov (United States)

    Williams, Richard; Measures, Richard; Hicks, Murray; Brasington, James

    2017-04-01

    Advances in geomatics technologies have transformed the monitoring of reach-scale (100-101 km) river morphodynamics. Hyperscale Digital Elevation Models (DEMs) can now be acquired at temporal intervals that are commensurate with the frequencies of high-flow events that force morphological change. The low vertical errors associated with such DEMs enable DEMs of Difference (DoDs) to be generated to quantify patterns of erosion and deposition, and derive sediment budgets using the morphological approach. In parallel with reach-scale observational advances, high-resolution, two-dimensional, physics-based numerical morphodynamic models are now computationally feasible for unsteady, reach-scale simulations. In light of this observational and predictive progress, there is a need to identify appropriate metrics that can be extracted from DEMs and DoDs to assess model performance. Nowhere is this more pertinent than in braided river environments, where numerous mobile channels that intertwine around mid-channel bars result in complex patterns of erosion and deposition, thus making model assessment particularly challenging. This paper identifies and evaluates a range of morphological and morphological-change metrics that can be used to assess predictions of braided river morphodynamics at the timescale of single storm events. A depth-averaged, mixed-grainsize Delft3D morphodynamic model was used to simulate morphological change during four discrete high-flow events, ranging from 91 to 403 m3s-1, along a 2.5 x 0.7 km reach of the braided, gravel-bed Rees River, New Zealand. Pre- and post-event topographic surveys, using a fusion of Terrestrial Laser Scanning and optical-empirical bathymetric mapping, were used to produce 0.5 m resolution DEMs and DoDs. The pre- and post-event DEMs for a moderate (227m3s-1) high-flow event were used to calibrate the model. DEMs and DoDs from the other three high-flow events were used for model assessment using two approaches. First

  1. Analysis of a morphometric indicator subject to abrupt change in the sediment supply in a braided stream: an experimental study

    Science.gov (United States)

    Vito Papa, Daniel; Ancey, Christophe

    2017-04-01

    Braiding is a complex fluvial process in which sediment-laden water flows are split into multiple threads. Thread joining and splitting at the nodes occurs continuously in the floodplain. Understanding how braiding responds to external factors is a key issue. A number of braided-pattern intensity indices have been proposed to characterize the degree of braiding. Due to the inherent complexity of their dynamics braided rivers exhibit a complex morphology that is difficult to study using simple indices. In this study, we propose a series of experiments to investigate the influence of sediment supply in the evolution of the braiding patterns. To that end, we use a set of morphological indicators, including the index proposed by Redolfi et al. (2016). The experiments are carried out in a 4-m-long and 1-m-wide flume. The bed is made of moderately sorted sand grains whose median diameter is 1 mm. A classic braided pattern configuration composed of various channels, confluences and bifurcations is observed. The experiments satisfy the Froude similarity criterion. Each run starts from an initial straight channel with rectangular cross section. After a certain time (approximately 40 hours) the system reaches equilibrium. This equilibrium is then perturbed by suddenly increasing the sediment feeding until a new point of equilibrium is reached (this takes approximately 40 hours again). During the whole run, bed elevation and water height are measured optically using laser sheets projected on the bed surface. Cross sections are calculated at 2 cm intervals from each others. The entire morphology is then obtained from these cross sections every hour. Sediment is feeded at the flume inlet and sediment transport rates are measured every 15 minutes at the flume outlet.

  2. Experimental studies on the flow through soft tubes and channels

    Indian Academy of Sciences (India)

    Keywords. Laminar-turbulent transition; soft tubes/channels; hydrodynamic stability; transition; turbulence; internal flows. Abstract. Experiments conducted in channels/tubes with height/diameter less than 1 mm with soft walls made of polymer gels show that the transition Reynolds number could be significantly lower than ...

  3. Neural Tube Defects

    Science.gov (United States)

    ... vitamin, before and during pregnancy prevents most neural tube defects. Neural tube defects are usually diagnosed before the infant is ... or imaging tests. There is no cure for neural tube defects. The nerve damage and loss of function ...

  4. Development of new nerve guide tube for repair of long nerve defects.

    Science.gov (United States)

    Ichihara, Satoshi; Inada, Yuji; Nakada, Akira; Endo, Katsuaki; Azuma, Takashi; Nakai, Ryusuke; Tsutsumi, Sadami; Kurosawa, Hisashi; Nakamura, Tatsuo

    2009-09-01

    A novel nerve guide tube (poly (L-lactic) acid (PLLA)/ polyglycolic acid (PGA)-c-tube) capable of repairing long peripheral nerve injuries in a canine model has been developed. The tube was created by braiding together PLLA and PGA and then coating it with collagen. PLLA was newly added to the formulation to achieve higher sustainability. The tube was compared with a PGA-collagen tube in clinical use since 2002 having the same structure with a collagen coating but composed of PGA alone (PGA-c-tube). When tested for repair of a 40-mm gap in the left peroneal nerve, using PLLA/PGA-c-tube (n = 15), PGA-c-tube (n = 15), and a negative control group where the cut stump was capped using a silicone cap (n = 15), the lumen structure essential for securing the space for nerve regeneration was maintained in PLLA/PGA-c-tube for over 12 months with a higher number of axons both within the tube and at the distal nerve end. Electrophysiological evaluation revealed that the amplitude of compound muscle action potentials and sensory nerve action potentials after nerve regeneration with PLLA/PGA-c-tube were significantly higher. When assessed using magnetic resonance imaging (MRI), the volume of the tibialis anterior (TA) muscle in dogs that had undergone nerve repair using PLLA/PGA-c-tube was approximately 80% that of the positive control at 12 months. Functional analysis conducted by assessing the ankle angle revealed faster recovery in the PLLA/PGA-c-tube group. Better regeneration was achieved using a PLLA/PGA-c-tube that contains the slowly decomposing fiber material, PLLA. This indicates potential for repair of even longer nerve gaps or defects located near joints, and also clinical application.

  5. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  6. Transverse Tensile Properties of 3 Dimension-4 Directional Braided Cf/SiC Composite Based on Double-Scale Model

    Science.gov (United States)

    Niu, Xuming; Sun, Zhigang; Song, Yingdong

    2017-11-01

    In this thesis, a double-scale model for 3 Dimension-4 directional(3D-4d) braided C/SiC composites(CMCs) has been proposed to investigate mechanical properties of it. The double-scale model involves micro-scale which takes fiber/matrix/porosity in fibers tows into consideration and the unit cell scale which considers the 3D-4d braiding structure. Basing on the Micro-optical photographs of composite, we can build a parameterized finite element model that reflects structure of 3D-4d braided composites. The mechanical properties of fiber tows in transverse direction are studied by combining the crack band theory for matrix cracking and cohesive zone model for interface debonding. Transverse tensile process of 3D-4d CMCs can be simulated by introducing mechanical properties of fiber tows into finite element of 3D-4d braided CMCs. Quasi-static tensile tests of 3D-4d braided CMCs have been performed with PWS-100 test system. The predicted tensile stress-strain curve by the double scale model finds good agreement with the experimental results.

  7. Braided River Evolution and Bifurcation Dynamics During Floods and Low Flow in the Jamuna River

    Science.gov (United States)

    Marra, W. A.; Kleinhans, M. G.; Addink, E.

    2010-12-01

    River bifurcations have become recognised over the last decade as being critical but poorly understood elements in many channel systems, including braided and anastomosing rivers, fluvial lowland plains and deltas. They control the partitioning of both water and sediment with consequences for the downstream evolution and for river and coastal management. Avulsion studies and bifurcation modelling suggest that symmetrical bifurcations are inherently unstable. However, the simultaneous activity of channels in deltas, anastomosing rivers and large braided rivers such as the Jamuna suggest that symmetrical bifurcations are stable in agreement with sediment transport optimisation theories. These theories are still a matter of debate. Our objective is to understand the stability and evolution of the braid pattern through studying the dynamics of the bifurcations under natural discharge conditions: both during floods and low flow. Using a series of Landsat TM images taken at irregular intervals showing inter-annual variation, we studied the evolution of a large number of bifurcations in the Jamuna river between 1999 and 2004. The images were first classified into water, bare sediment and vegetation. The contiguous water body of the river was then selected and translated into a network description with bifurcations and confluences at the nodes and interconnecting channels. Channel width is a crucial attribute of the network channels as this allows the calculation of bifurcation asymmetry. The key step here is to describe river network evolution by identifying the same node in multiple subsequent images as well as new and abandoned nodes, in order to distinguish migration of bifurcations from avulsion processes. Nodes in two subsequent images were linked through distance and angle of the downstream connected channels. Once identified through time, the changes in node position and the changes in the connected channels can be quantified Along the entire river the well

  8. Many-body braiding phases in a rotating strongly correlated photon gas

    Energy Technology Data Exchange (ETDEWEB)

    Umucalılar, R.O., E-mail: rifatonur.umucalilar@ua.ac.be; Carusotto, I.

    2013-11-01

    We present a theoretical study of fractional quantum Hall physics in a rotating gas of strongly interacting photons in a single cavity with a large optical nonlinearity. Photons are injected into the cavity by a Laguerre–Gauss laser beam with a non-zero orbital angular momentum. The Laughlin-like few-photon eigenstates appear as sharp resonances in the transmission spectra. Using additional localized repulsive potentials, quasi-holes can be created in the photon gas and then braided around in space: an unambiguous signature of the many-body Berry phase under exchange of two quasi-holes is observed as a spectral shift of the corresponding transmission resonance.

  9. Event-Scale Morphodynamics and Sediment Sorting in a Dynamic Braided River Revealed by TLS

    Science.gov (United States)

    Vericat, D.; Brasington, J.

    2008-12-01

    In the last decade, advances in topographic survey and digital elevation modelling have enabled a revolution in the study of fluvial morphodynamics. Despite this recent progress, our understanding of braided river dynamics remains limited by the time-space scale of studies. Hindered by high labour and flight costs, together with slow ground-based survey methods, studies to date have focused either on event-scale dynamics of morphological units (Ferguson and Ashworth, 1992; Lane et al., 1995; Milan et al., 2007) or seasonal-annual dynamics of larger system-scale reaches (sensu Lane, 2006; e.g., Brasington et al., 2003; Lane et al., 2003). Terrestrial Laser Scanning technology offers the potential to acquire rapidly, reach-scale datasets which record topographic information at the resolution of bed grain-scale upwards. However, as yet, no detailed 3d datasets exist that reveal the system-scale evolution of a braided river through a continuous sequence of floods. Such data are urgently required to address unresolved and fundamental questions concerning the controls and behaviour of braided rivers and are also needed to validate morphodynamic simulation models (Brasington and Richards, 2007). Our recent wok has demonstrated that TLS can be applied to recover centimetre-scale channel morphology, maps of particle size, sorting, packing and floodplain roughness (Brasington et al., 2007, 2008; Antonarakis, 2008a,b; Hodge et al., in review). This potential is illustrated by the results obtained in a field study conducted in January 2008. This used TLS to monitor the evolution of channel morphology and develop methods to derive models of bed roughness and facies in a small 500 x 300 m reach of the actively braided Rees River, New Zealand. Fieldwork comprised repeat surveys before and after 3 competent events, combining laser scans from eight positions with bathymetric data obtained by RTK GPS. The resulting point clouds incorporated between 48-110 million survey points, with

  10. Many-body braiding phases in a rotating strongly correlated photon gas

    OpenAIRE

    Umucalilar, R. O.; Carusotto, I.

    2012-01-01

    We present a theoretical study of a rotating trapped photon gas where a Laguerre-Gauss laser pump with a non-zero orbital angular momentum is used to inject rotating photons into a cavity with strong optical nonlinearity. The Laughlin-like few-photon eigenstates appear as sharp resonances in the transmission spectra. Using additional localized repulsive potentials, quasi-holes can be created in the quantum Hall liquid of photons and then braided around in space: an unambiguous signature of th...

  11. The Fabrication, Processing and Characterization of Multidimensionally Braided Graphite/Epoxy Composite Materials

    Science.gov (United States)

    1984-10-01

    prepared and tested according to the following ASTM methods. ASTM D3039 -76: Tensile Properties of Oriented Fiber Composites ASTM D3410-75...The testing procedure followed was that given in the standard ASTM 03039-76. Five strain gages with a grid width of 6.4 mm (0.25 in.) were mounted on...Modulus, EXT’ of a 7.6 em (3 inch) 3 x 1 Braided Panei as Function of Width Page 13 17 20 27 LIST OF ABBREVIATIONS ASTM American Society for

  12. Nasogastric feeding tube

    Science.gov (United States)

    ... of what to do. What to Expect at Home If your child has an NG tube, try to keep your child from touching or pulling on the tube. After your nurse teaches you how to flush the tube and perform skin care around the nose, set up a daily routine for these tasks. Flushing the Tube Flushing the ...

  13. Dynamics in Polymer Nanocomposites

    Science.gov (United States)

    Clarke, Nigel

    2015-03-01

    Since nanoparticles are increasingly being added to polymers to impart mechanical and functional properties, we are exploring how nanoparticles impact polymer dynamics with a focus on the diffusion coefficients. In high molecular weight polymer melts, chain diffusion is well described by the reptation model. Motion proceeds as a snake-like diffusion of the chain as a whole, along the contour of a tube that mimics the role of physical entanglements, or topological constraints, with other chains. In polymer nanocomposites there are additional constraints due to the dispersed nanoparticles in the polymer matrix. Chain motion can be altered by nanoparticle size, shape , aspect ratio, surface area, loading and the nature of the interactions between the nanoparticles and the polymer matrix. We have observed a minimum in the diffusion coefficient as a function of nanoparticle concentration when the nanoparticles are rod-like and a collapse of the diffusion coefficient onto a master curve when the nanoparticles are spherical. We are simulating the dynamics using molecular and dissipative particle simulations in order to provide physical insight into the local structure and dynamics, and have also carried out highly coarse grained Monte Carlo simulations of entangled polymers to explore how reptation is affected by the presence of larger scale obstacles. We acknowledge support from the NSF/EPSRC Materials World Network Program.

  14. Modelling the side impact of carbon fibre tubes

    Science.gov (United States)

    Sudharsan, Ms R.; Rolfe, B. F., Dr; Hodgson, P. D., Prof

    2010-06-01

    Metallic tubes have been extensively studied for their crashworthiness as they closely resemble automotive crash rails. Recently, the demand to improve fuel economy and reduce vehicle emissions has led automobile manufacturers to explore the crash properties of light weight materials such as fibre reinforced polymer composites, metallic foams and sandwich structures in order to use them as crash barriers. This paper discusses the response of carbon fibre reinforced polymer (CFRP) tubes and their failure mechanisms during side impact. The energy absorption of CFRP tubes is compared to similar Aluminium tubes. The response of the CFRP tubes during impact was modelled using Abaqus finite element software with a composite fabric material model. The material inputs were given based on standard tension and compression test results and the in-plane damage was defined based on cyclic shear tests. The failure modes and energy absorption observed during the tests were well represented by the finite element model.

  15. Deformation mechanisms of prototype composite braided stent-grafts in bending fatigue for peripheral artery application.

    Science.gov (United States)

    Xue, Wen; Gao, Jing; Lin, Jing; Wang, Fujun; Guan, Guoping; Wang, Lu

    2017-10-31

    Stent-grafts in peripheral arteries suffer from complex cyclic loadings in vivo, including pulsatile, axial bending and torsion. Normal fatigue durability evaluation technologies, however, are majorly based on pulsation and thus are short of accuracy under the complicated stress conditions experienced physiologically. While there is a little research focused on the cyclic fatigue of stent-grafts in bending, it remains an almost total lack of deformation or fatigue mechanisms. In this work, composite braided stent-grafts incorporating Nitinol (NiTi) yarns and polyethylene terephthalate (PET) multifilament yarns were cycled in bending by the self-developed testing system to investigate their deformation behaviors. Deformation mechanisms at the yarn level were discussed, and NiTi yarn crossover structure was considered the primary factor affecting the deformation modes. Four yarn-crossover-based deformation modes (accordion buckling, diamond-shaped buckling, neck propagation and microbuckling) revealed the mechanisms of energy absorption of braided stent-grafts on the mesoscopic scale. Further, mechanical modes were applied to help regulate stent designs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Development of hybrid braided composite rods for reinforcement and health monitoring of structures.

    Science.gov (United States)

    Rana, Sohel; Zdraveva, Emilija; Pereira, Cristiana; Fangueiro, Raul; Correia, A Gomes

    2014-01-01

    In the present study, core-reinforced braided composite rods (BCRs) were developed and characterized for strain sensing capability. A mixture of carbon and glass fibre was used in the core, which was surrounded by a braided cover of polyester fibres. Three compositions of core with different carbon fibre/glass fibre weight ratios (23/77, 47/53, and 100/0) were studied to find out the optimum composition for both strain sensitivity and mechanical performance. The influence of carbon fibre positioning in BCR cross-section on the strain sensing behaviour was also investigated. Strain sensing property of BCRs was characterized by measuring the change in electrical resistance with flexural strain. It was observed that BCRs exhibited increase (positive response) or decrease (negative response) in electrical resistance depending on carbon fibre positioning. The BCR with lowest amount of carbon fibre was found to give the best strain sensitivity as well as the highest tensile strength and breaking extension. The developed BCRs showed reversible strain sensing behaviour under cyclic flexural loading with a maximum gauge factor of 23.4 at very low strain level (0.55%). Concrete beams reinforced with the optimum BCR (23/77) also exhibited strain sensing under cyclic flexural strain, although the piezoresistive behaviour in this case was irreversible.

  17. Development of braided rope seals for hypersonic engine applications: Flow modeling

    Science.gov (United States)

    Mutharasan, Rajakkannu; Steinetz, Bruce M.; Tao, Xiaoming; Du, Guang-Wu; Ko, Frank

    1992-01-01

    A new type of engine seal is being developed to meet the needs of advanced hypersonic engines. A seal braided of emerging high temperature ceramic fibers comprised of a sheath-core construction was selected for study based on its low leakage rates. Flexible, low-leakage, high temperature seals are required to seal the movable engine panels of advanced ramjet-scramjet engines either preventing potentially dangerous leakage into backside engine cavities or limiting the purge coolant flow rates through the seals. To predict the leakage through these flexible, porous seal structures new analytical flow models are required. Two such models based on the Kozeny-Carman equations are developed herein and are compared to experimental leakage measurements for simulated pressure and seal gap conditions. The models developed allow prediction of the gas leakage rate as a function of fiber diameter, fiber packing density, gas properties, and pressure drop across the seal. The first model treats the seal as a homogeneous fiber bed. The second model divides the seal into two homogeneous fiber beds identified as the core and the sheath of the seal. Flow resistances of each of the main seal elements are combined to determine the total flow resistance. Comparisons between measured leakage rates and model predictions for seal structures covering a wide range of braid architectures show good agreement. Within the experimental range, the second model provides a prediction within 6 to 13 percent of the flow for many of the cases examined. Areas where future model refinements are required are identified.

  18. Braiding by Majorana tracking and long-range CNOT gates with color codes

    Science.gov (United States)

    Litinski, Daniel; von Oppen, Felix

    2017-11-01

    Color-code quantum computation seamlessly combines Majorana-based hardware with topological error correction. Specifically, as Clifford gates are transversal in two-dimensional color codes, they enable the use of the Majoranas' non-Abelian statistics for gate operations at the code level. Here, we discuss the implementation of color codes in arrays of Majorana nanowires that avoid branched networks such as T junctions, thereby simplifying their realization. We show that, in such implementations, non-Abelian statistics can be exploited without ever performing physical braiding operations. Physical braiding operations are replaced by Majorana tracking, an entirely software-based protocol which appropriately updates the Majoranas involved in the color-code stabilizer measurements. This approach minimizes the required hardware operations for single-qubit Clifford gates. For Clifford completeness, we combine color codes with surface codes, and use color-to-surface-code lattice surgery for long-range multitarget CNOT gates which have a time overhead that grows only logarithmically with the physical distance separating control and target qubits. With the addition of magic state distillation, our architecture describes a fault-tolerant universal quantum computer in systems such as networks of tetrons, hexons, or Majorana box qubits, but can also be applied to nontopological qubit platforms.

  19. GoldenBraid: An Iterative Cloning System for Standardized Assembly of Reusable Genetic Modules

    Science.gov (United States)

    Sarrion-Perdigones, Alejandro; Falconi, Erica Elvira; Zandalinas, Sara I.; Juárez, Paloma; Fernández-del-Carmen, Asun; Granell, Antonio; Orzaez, Diego

    2011-01-01

    Synthetic Biology requires efficient and versatile DNA assembly systems to facilitate the building of new genetic modules/pathways from basic DNA parts in a standardized way. Here we present GoldenBraid (GB), a standardized assembly system based on type IIS restriction enzymes that allows the indefinite growth of reusable gene modules made of standardized DNA pieces. The GB system consists of a set of four destination plasmids (pDGBs) designed to incorporate multipartite assemblies made of standard DNA parts and to combine them binarily to build increasingly complex multigene constructs. The relative position of type IIS restriction sites inside pDGB vectors introduces a double loop (“braid”) topology in the cloning strategy that allows the indefinite growth of composite parts through the succession of iterative assembling steps, while the overall simplicity of the system is maintained. We propose the use of GoldenBraid as an assembly standard for Plant Synthetic Biology. For this purpose we have GB-adapted a set of binary plasmids for A. tumefaciens-mediated plant transformation. Fast GB-engineering of several multigene T-DNAs, including two alternative modules made of five reusable devices each, and comprising a total of 19 basic parts are also described. PMID:21750718

  20. Biodegradable Polymers

    OpenAIRE

    Isabelle Vroman; Lan Tighzert

    2013-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  1. Effect of Heat Treatment and Salt Concentration on Free Amino Acids Composition of Sudanese Braided (Muddaffara Cheese during Storage

    Directory of Open Access Journals (Sweden)

    Mohamed O. E. Altahir

    2014-08-01

    Full Text Available The aim of this study was to assess the effect of heat treatment and salt concentrations (0, 5, and 10% on the free amino acids (FAA composition of Sudanese braided cheese (BC ripened for up to 3 months at 5±2°C. Heat and salt concentration significantly affected the FAA of braided cheese. The free amino acids concentrations of BC ripened in 0%, 5%, and 10% salted whey (SW were significantly fluctuated. Under ripening conditions tested (salt level + time, braided cheese made from pasteurized milk (BCPM had consistently lower values of FAA than braided cheese made from raw milk (BCRM. In fresh cheese, the major FAA in BCRM were Glu (36.12 nmol/ml, Leu (26.77nmol/ml and Lys (14.51 nmol/ml while the major ones in BCPM were Lys (2.94 nmol/ml and Ala (2.45 nmol/ml. BCPM stored in 10% SW had shorter quality life compared to that stored in 5% salted whey.

  2. Fatigue resistance of unnotched and post impact(+/- 30 deg/0 deg) 3-D braided composites. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Portanova, M.A.

    1994-01-01

    The fatigue resistance of a multiaxial braided (3-D) graphite/expoxy composite in both unnotched and post impacted conditions has been evaluated. The material tested is a (+/- 30/0 deg) multiaxial braid constructed from AS4/12K tow graphite fibers and British Petroleum E905L epoxy resin. These materials were braided as dry preforms and the epoxy was added using a resin transfer molding process (RTM). The unnotched and post-impact specimens were tested in compression-compression fatigue at 10 Hz with a stress ratio of R=10. The unnotched tension-tension fatigue specimens were tested at S Hz with a stress ration of R=0.1. Damage initiation and growth was documented through the application of radiography and ultrasonic through transmission (C-scans). Visible inspection of surface and edge damage was also noted to describe the initiation and progression of damage in these materials. The mechanisms leading to damage initiation were established and failure modes were determined. Stiffness and strength degradation were measured as a function of applied cycles. These 3-D braided composite results were compared to strain levels currently used to design primary structure in commercial aircraft composite components made from prepreg tape and autoclave cured.

  3. Rapid Polymer Sequencer

    Science.gov (United States)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  4. Entangled polymer complexes as Higgs phenomena.

    Science.gov (United States)

    Kim, Ki-Seok; Dutta, Sandipan; Jho, YongSeok

    2015-10-28

    We derive an effective Maxwell-London equation for entangled polymer complexes under topological constraints, borrowing the theoretical framework from topological field theory. We find that the transverse current flux of a test polymer chain, surrounded by entangled chains, decays exponentially from its centerline position with a finite penetration depth, which is analogous to the magnetic-field decay in a superconductor (SC), referred to as the Meissner effect. Just as the mass acquirement of photons in a SC is the origin of the magnetic-field decay, the polymer obtains uncrossable intersections along the chain due to the preservation of the linking number, which restricts the deviation of the transverse polymer current in the normal direction. The underlying physics is as follows: less flexible polymers have stronger current-current correlations, giving rise to a heavier effective mass of the gauge fields and resulting in a shorter decay length. Interestingly, this picture is well incorporated within the most successful phenomenological theory of the, so called, tube model, the microscopic origins of which researchers have long pursued. The correspondence of our equation of motion to the tube model claims that the confining tube potential is a consequence of the topological constraint (linking number). The tube radius is attributed to the decay length. On increasing the effective mass (by strengthening the interaction at an uncrossable intersection or a number of intersections), the tube becomes narrower. Using this argument, the exponential decay of the chain leakage out of the tube is well understood.

  5. Discontinuities in braided patterns: The River Rhône from Geneva to the Camargue delta before river training

    Science.gov (United States)

    Bravard, Jean-Paul

    2010-05-01

    This study presents the upstream-downstream complexity of the Rhone, which earlier was a braided river. The fluvial patterns of the Rhône ca. 1860-70 are discussed, i.e. at the end of the Little Ice Age, which was also the beginning of the period of river dredging for improving navigation in the channel (1840-1930) and before the development of a chain of hydroelectric dams (1892-1986) on the river. Flowing across Switzerland and France to the Camargue delta on the Mediterranean, the Rhône drains the western part of the Alps in Europe. Befitting a large river flowing from the mountains, the Rhône was braided along most of its course, due to large quantities of coarse sediments formerly contributed by tributaries from the Alps, Jura Mountains, and Massif Central. The paper begins with a summary of palaeo-environmental studies on the Rhône, which show that the river experienced several events of fluvial metamorphosis during the Holocene. The reaches, which were braided during the late 19th century, alternated between meandering and braided patterns during this period due to the high sensitivity of the channel pattern to external variables such as changing water and sediment discharges. A discussion on the methods used to describe different aspects of the braided pattern of the Rhône from 1860 to 1870, using large-scale maps follows. Discrete reaches on the river are identified using slope, downstream variations of discharge, and stream power. These can be attributed to three factors: the tributaries (large supplies of bed load are brought by the Arve, the Ain, the Drôme, the Ardèche and the Durance rivers), Quaternary tectonics, and the along-channel distance from tributary confluences. Finally, the study assesses the pre-modern conditions of the Rhône for restoring selected reaches on the modern river.

  6. Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

    Directory of Open Access Journals (Sweden)

    Ziliang Liu

    Full Text Available A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km. The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front

  7. Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

    Science.gov (United States)

    Liu, Ziliang; Shen, Fang; Zhu, Xiaomin; Li, Fengjie; Tan, Mengqi

    2015-01-01

    A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km). The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front" character.

  8. Design and construction of multigenic constructs for plant biotechnology using the GoldenBraid cloning strategy.

    Science.gov (United States)

    Sarrion-Perdigones, Alejandro; Palaci, Jorge; Granell, Antonio; Orzaez, Diego

    2014-01-01

    GoldenBraid (GB) is an iterative and standardized DNA assembling system specially designed for Multigene Engineering in Plant Synthetic Biology. GB is based on restriction-ligation reactions using type IIS restriction enzymes. GB comprises a collection of standard DNA pieces named "GB parts" and a set of destination plasmids (pDGBs) that incorporate the multipartite assembly of standardized DNA parts. GB reactions are extremely efficient: two transcriptional units (TUs) can be assembled from several basic GBparts in one T-DNA less than 24 h. Moreover, larger assemblies comprising 4-5 TUs are routinely built in less than 2 working weeks. Here we provide a detailed view of the GB methodology. As a practical example, a Bimolecular Fluorescence Complementation construct comprising four TUs in a 12 kb DNA fragment is presented.

  9. Twisted quantum Z{sub n} modular data and braided subfactors

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Paulo R [Centro de Analise Matematica, Geometria e Sistemas Dinamicos, Department of Mathematics, Instituto Superior Tecnico, Av Rovisco Pais, 1049-001 Lisboa (Portugal)

    2007-08-03

    The modular data from twisted [k] element of H{sup 3}(G,T) quantum double of finite groups G are studied, with G=Z{sub n} cyclic groups. It is proved that the [k] and [ - k] modular data are the same up to relabelling of the primary fields and complex conjugation of the underlying representation of the modular group SL(S,Z). Then we produce some lower bounds for the number of modular invariants of these models, and complete the study for the cases G=Z{sub 2},Z{sub 3} and Z{sub 4} at all twists, proving in particular that all their modular invariants are produced by braided subfactors.

  10. Investigation of Carbon Fiber Architecture in Braided Composites Using X-Ray CT Inspection

    Science.gov (United States)

    Rhoads, Daniel J.; Miller, Sandi G.; Roberts, Gary D.; Rauser, Richard W.; Golovaty, Dmitry; Wilber, J. Patrick; Espanol, Malena I.

    2017-01-01

    During the fabrication of braided carbon fiber composite materials, process variations occur which affect the fiber architecture. Quantitative measurements of local and global fiber architecture variations are needed to determine the potential effect of process variations on mechanical properties of the cured composite. Although non-destructive inspection via X-ray CT imaging is a promising approach, difficulties in quantitative analysis of the data arise due to the similar densities of the material constituents. In an effort to gain more quantitative information about features related to fiber architecture, methods have been explored to improve the details that can be captured by X-ray CT imaging. Metal-coated fibers and thin veils are used as inserts to extract detailed information about fiber orientations and inter-ply behavior from X-ray CT images.

  11. The challenges in using UAV and plane imagery to quantify channel change in sandy braided rivers

    Science.gov (United States)

    Strick, Robert; Ashworth, Philip; Best, James; Lane, Stuart; Nicholas, Andrew; Parsons, Daniel; Sambrook Smith, Gregory; Simpson, Christopher; Unsworth, Christopher

    2017-04-01

    The development of numerical models of river morpho-dynamics is hampered by the lack of high-resolution data at multiple time and space scales for model validation. Such data are especially challenging to obtain for sand-bed braided rivers that typically have multiple channels of varying depth and contain rapidly migrating low-relief bar-lobes and dunes. This paper reports on the efforts to meet these challenges using repeat UAV surveys and plane sorties to quantify morphological change and bedform migration rates along the South Saskatchewan River, Canada. The South Saskatchewan River, near Outlook (SK Province) is 600 m wide with very well sorted medium sand (D50 = 0.3 mm) and negligible clay. The Gardiner Dam, 20 km upstream of the study reach, traps much of the very fine sediment so that the waters are clear at low flow and therefore the river bed is entirely visible. Fieldwork campaigns in 2015 and 2016 captured: (i) 1:5000 aerial colour photographs over a 17.5 km reach; (ii) high temporal frequency repeat imagery, obtained using quadcopter and fixed-wing UAV platforms for multiple 100 x 500 m sub-reaches. Plane images were processed via Structure from Motion (SfM) photogrammetric techniques using Pix4D and supporting ArcGIS and Global Mapper analysis. The resulting point cloud was corrected for tilt and filtered in MATLAB at multiple spatial scales to remove noise. Elevations in sub-aqueous zones were obtained using a statistical model, relating image brightness to water depth, developed using single beam echo-sounder data collected near to the flight time. The final DSM for the plane imagery combines these two methods and has a 0.5 m spatial resolution with vertical accuracy of 6 cm. UAV imagery is also processed using Pix4D with application of a diffraction water depth correction, required due to the lower flight height, and gives a resulting vertical accuracy of 2 cm. Initial results highlight the following issues: (i) there are a series of technical

  12. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. By inserting the nano- metric inorganic compounds, the properties of polymers improve and hence this has a lot of applications depending upon the inorganic material present in the polymers. Sol- vent casting is one of the easiest ...

  13. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources or from biological resources (renewable resources. In general natural polymers offer fewer advantages than synthetic polymers. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  14. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  15. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: ...

  16. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia ... of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia ...

  17. NEI You Tube Videos: Amblyopia

    Science.gov (United States)

    ... YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia ... of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia ...

  18. Pulse Tube Refrigerator

    Science.gov (United States)

    Matsubara, Yoichi

    The pulse tube refrigerator is one of the regenerative cycle refrigerators such as Stirling cycle or Gifford-McMahon cycle which gives the cooling temperature below 150 K down to liquid helium temperature. In 1963, W. E. Gifford invented a simple refrigeration cycle which is composed of compressor, regenerator and simple tube named as pulse tube which gives a similar function of the expander in Stirling or Gifford-McMahon cycle. The thermodynamically performance of this pulse tube refrigerator is inferior to that of other regenerative cycles. In 1984, however, Mikulin and coworkers made a significant advance in pulse tube configuration called as orifice pulse tube. After this, several modifications of the pulse tube hot end configuration have been developed. With those modifications, the thermodynamic performance of the pulse tube refrigerator became the same order to that of Stirling and Gifford-McMahon refrigerator. This article reviews the brief history of the pulse tube refrigerator development in the view point of its thermodynamically efficiency. Simplified theories of the energy flow in the pulse tube have also been described.

  19. Mechanical behavior of a triaxially braided textile composite at high temperature

    Science.gov (United States)

    El Mourid, Amine

    The work presented in this thesis aimed at understanding the influence of viscoelasticity, temperature and aging on the mechanical behaviour of a textile composite using experimental, analytical and numerical tools. The studied material was a triaxially braided composite with fibres in the 0°/+/-60° directions. The yarns were made of carbon fibres, embedded in an MVK10 temperature resistant polyimide matrix. The first step consisted in developing analytical and numerical frameworks to predict viscoelastic behaviour in textile composites. Simulations were performed for both braided and woven textile architectures, at different stiffness contrasts and yarns volume fractions. The analytical framework accuracy was verified with the help of the numerical simulations. An important finding of this study was that the analytical framework, combined with the Mori-Tanaka model, leads to relatively accurate predictions for both the permanent and transient parts. Therefore, the authors believe that the Mori-Tanaka model with an adjusted aspect ratio to take into account yarn curvature is reliable for predicting viscoelastic behaviour in textile composites. The textile composite that was studied in this project did not display viscoelastic behaviour, due to the high yarn volume fraction. However, the framework remains relevant for higher temperature applications or lower yarn volume fractions. The second step was to investigate the temperature effect on the tensile behavior of the carbon/MVK10 triaxially braided composite material studied in this project. To achieve this goal, a series of room and high temperature tensile tests on both matrix and composite samples were performed. The tests on composite samples were performed along two different material directions at the maximum service temperature allowed by the Federal Aviation Administration for aircraft components, and a dedicated replication technique was developed in order to track crack densities as a function of

  20. Miscible displacement of a non-Newtonian fluid in a capillary tube

    Science.gov (United States)

    Soori, Tejaswi; Ward, Thomas

    2017-11-01

    This talk focuses on experiments conducted to further our understanding of how to displace an aqueous polymer within a capillary tube (diameter range of shear rates and fit the data obtained to the Carreau fluid parameters. Separately we measure the average bulk diffusion coefficient of the aqueous polymer and water in water and aqueous polymer phases respectively. Previous studies on the immiscible displacement of polymers have shown residual film thickness to be dependent on the tube diameter. We will investigate if this is true when the two fluids are miscible in nature. American Chemical Society Petroleum Research Fund.

  1. Categorising YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube......’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition...... and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within...

  2. Tenogenic differentiation of human induced pluripotent stem cell-derived mesenchymal stem cells dictated by properties of braided submicron fibrous scaffolds.

    Science.gov (United States)

    Czaplewski, Sarah K; Tsai, Tsung-Lin; Duenwald-Kuehl, Sarah E; Vanderby, Ray; Li, Wan-Ju

    2014-08-01

    Tendon and ligament (T/L) engineering is a growing area of research with potential to address the inadequacies of current T/L defect treatments. Our group previously developed braided submicron fibrous scaffolds (BSMFSs) and demonstrated the viability of BSMFSs for T/L tissue engineering. The objective of this study was to investigate the effect of fiber chemistry and braiding angle on BSMFS mechanical properties and in turn, tenogenic differentiation of human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs) seeded on BSMFSs subjected to cyclic tensile stimulation in the absence of tenogenic medium. By varying fiber chemistry and/or braiding angle, BSMFSs with a range of mechanical properties were produced. We found that fiber chemistry dictated cell adhesion while braiding angle dictated the tissue-specific lineage commitment of hiPSC-MSCs. Scaffolds braided with large angles better supported hiPSC-MSC tenogenic differentiation as evidenced by the production of T/L-associated markers, downregulation of osteogenic markers, and expression of fibroblast-like, spindle cell morphology compared to scaffolds braided with small angles. Our results demonstrate the importance of substrate properties and mechanical stimulation on tenogenic differentiation. These results also demonstrate the versatility of BSMFSs and the potential of hiPSC-MSCs for T/L tissue engineering. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Retrograde Gastrojejunostomy Tube Migration

    Directory of Open Access Journals (Sweden)

    Adeleke Adesina

    2014-01-01

    Full Text Available Percutaneous enteral feeding tubes are placed about 250,000 times each year in the United States. Although they are relatively safe, their placement may be complicated by perforation, infection, bleeding, vomiting, dislodgment, and obstruction. There have been numerous reports of antegrade migration of gastrojejunostomy (G-J tubes. We report a case of G-J tube regurgitation following protracted vomiting and discuss the management of this very rare entity.

  4. Heated Tube Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Heated Tube Facility at NASA GRC investigates cooling issues by simulating conditions characteristic of rocket engine thrust chambers and high speed airbreathing...

  5. Modeling the topography of shallow braided rivers using Structure-from-Motion photogrammetry

    Science.gov (United States)

    Javernick, L.; Brasington, J.; Caruso, B.

    2014-05-01

    Recent advances in computer vision and image analysis have led to the development of a novel, fully automated photogrammetric method to generate dense 3d point cloud data. This approach, termed Structure-from-Motion or SfM, requires only limited ground-control and is ideally suited to imagery obtained from low-cost, non-metric cameras acquired either at close-range or using aerial platforms. Terrain models generated using SfM have begun to emerge recently and with a growing spectrum of software now available, there is an urgent need to provide a robust quality assessment of the data products generated using standard field and computational workflows. To address this demand, we present a detailed error analysis of sub-meter resolution terrain models of two contiguous reaches (1.6 and 1.7 km long) of the braided Ahuriri River, New Zealand, generated using SfM. A six stage methodology is described, involving: i) hand-held image acquisition from an aerial platform, ii) 3d point cloud extraction modeling using Agisoft PhotoScan, iii) georeferencing on a redundant network of GPS-surveyed ground-control points, iv) point cloud filtering to reduce computational demand as well as reduce vegetation noise, v) optical bathymetric modeling of inundated areas; and vi) data fusion and surface modeling to generate sub-meter raster terrain models. Bootstrapped geo-registration as well as extensive distributed GPS and sonar-based bathymetric check-data were used to quantify the quality of the models generated after each processing step. The results obtained provide the first quantified analysis of SfM applied to model the complex terrain of a braided river. Results indicate that geo-registration errors of 0.04 m (planar) and 0.10 m (elevation) and vertical surface errors of 0.10 m in non-vegetation areas can be achieved from a dataset of photographs taken at 600 m and 800 m above the ground level. These encouraging results suggest that this low-cost, logistically simple method can

  6. Survival of flexible, braided, bonded stainless steel lingual retainers: a historic cohort study.

    Science.gov (United States)

    Lie Sam Foek, D J; Ozcan, M; Verkerke, G J; Sandham, A; Dijkstra, P U

    2008-04-01

    The objectives of this study were to retrospectively evaluate the clinical survival rate of flexible, braided, rectangular bonded stainless steel lingual retainers, and to investigate the influence of gender, age of the patient, and operator experience on survival after orthodontic treatment at the Department of Orthodontics, University of Groningen, between the years 2002 and 2006. The study group comprised of 277 patients [162 females: median age 14.8 years, interquartile range (IQR) 13.6-16.5 years and 115 males: median age 15.3 years, IQR 14.2-16.7 years]. After acid etching the lingual surfaces of each tooth, an adhesive resin was applied and retainers were bonded using a flowable resin composite. Data concerning, failures, gender, age of the patient, and operator experience were retrieved from the patient files that were updated by chart entries every 6 months or when failure was reported by the patient. The maximum follow-up period was 41.7 months. All 277 patients received flexible, braided, bonded mandibular canine-to-canine retainers. Eighteen failures were observed in the maxilla. A failure was recorded when there was debonding, fracture, or both, occurring in one arch. Only first failures were used for statistical analysis. When failures occurred in both jaws, these were considered as two separate incidences. Ninety-nine debonding (35.7 per cent), two fractures (0.7 per cent), and four debonding and fracture (1.4 per cent) events were observed. No significant effect (P > 0.05) of gender (females: 41 per cent, males: 32 per cent) or patient age ( or =16 years 38.7 per cent) was observed. The failure rate did not differ due to operator experience (n = 15; less experienced: 38.0 per cent; moderately experienced: 28.9 per cent, professional: 46.7 per cent; P > 0.05; chi-square test). Kaplan-Meier survival curves showed a 63 per cent success rate for the bonded lingual retainers over a 41.7 month period.

  7. Using Remote-sensing to Survey Topography and Morphologic Change on Large Braided River Beds

    Science.gov (United States)

    Maurice, D.; Hicks, M.; Shankar, U.

    2007-12-01

    Since 1999 we have made extensive use of a variety of remote-sensing technologies to survey bed topography over reaches of large braided gravel-bed rivers on the east coast of New Zealand's South Island. The motivations have been (i) to collect input and validation data for 2-d hydrodynamic models for quantifying in-stream physical habitat and for predicting flood levels and (ii) to survey spatially-distributed riverbed erosion and deposition in order to estimate bedload fluxes by the 'morphological' method. Typical applications have been to river reaches 3-4 km long and 1 km wide, with grid cells from 1-5 m. We use different techniques to survey dry and wet areas of braided riverbed. For dry areas, we have used digital photogrammetry and infra-red airborne LiDAR. For wetted channels, we have generally used ortho-rectified colour imagery or multi-spectral scanning to map water depth, then we map bed topography by subtracting the water depth from a DEM of the water surface obtained from photogrammetry or LiDAR. The imagery is calibrated to water depth using field measurements on the day of imagery acquisition. Surveys are undertaken during low flows to maximise bed exposure. We use ground-based RTK-GPS and echo-sounding to collect calibration and validation data, and sometimes simply use these methods to survey the wetted areas. Orthoimagery at multiple river flows is used to validate 2-d model results. We have been able to achieve elevation accuracies at interpolated points of the order of 10-15 cm for dry areas. This accuracy typically degrades to 20-30 cm for wetted areas. Our experience has exposed a number of issues relating to survey accuracy and practicality at large river scales. These include: changing geoidal models between surveys; local systematic error with photogrammetric model mosaics; geospatial synchronisation of multi-platform data; time-synchronisation of LiDAR and imagery- collecting aeroplanes and suitable weather and river conditions

  8. Magnetic Structure of Sites of Braiding in Hi-C Active Region

    Science.gov (United States)

    Tiwari, S. K.; Alexander, C. E.; Winebarger, A.; Moore, R. L.

    2014-01-01

    High-resolution Coronal Imager (Hi-C) observations of an active region (AR) corona, at a spatial resolution of 0.2 arcsec, have offered the first direct evidence of field lines braiding, which could deliver sufficient energy to heat the AR corona by current dissipation via magnetic reconnection, a proposal given by Parker three decades ago. The energy required to heat the corona must be transported from the photosphere along the field lines. The mechanism that drives the energy transport to the corona is not yet fully understood. To investigate simultaneous magnetic and intensity structure in and around the AR in detail, we use SDO/HMI+AIA data of + / - 2 hours around the 5 minute Hi-C flight. In the case of the QS, work done by convection/granulation on the inter-granular feet of the coronal field lines probably translates into the heat observed in the corona. In the case of the AR, as here, there could be flux emergence, cancellation/submergence, or shear flows generating large stress and tension in coronal field loops which is released as heat in the corona. However, to the best of our knowledge, there is no observational evidence available to these processes. We investigate the changes taking place in the photospheric feet of the magnetic field involved with brightenings in the Hi-C AR corona. Using HMI 45s magnetograms of four hours we find that, out of the two Hi-C sub-regions where the braiding of field lines were recently detected, flux emergence takes place in one region and flux cancellation in the other. The field in these sub-regions are highly sheared and have apparent high speed plasma flows at their feet. Therefore, shearing flows plausibly power much of the coronal and transition region heating in these areas of the AR. In addition, the presence of large flux emergence/cancellation strongly suggests that the work done by these processes on the pre-existing field also drives much of the observed heating.

  9. Pollutant mixing and transport process via diverse transverse release positions in a multi-anabranch river with three braid bars

    Directory of Open Access Journals (Sweden)

    Zu-lin HUA

    2013-07-01

    Full Text Available A multi-anabranch river with three braid bars is a typical river pattern in nature, but no studies have been conducted to describe mixing characteristics of pollutants in the river. In this study, a physical model of a typical multi-anabranch river with three braid bars was established to explore the pollutant mixing characteristics in different branches. The multi-anabranch reach was separated into seven branches, B1, B2, B3, B4, B5, B6, and B7, by three braid bars. Five tracer release positions located 2.9 m upstream from the inlet section of the multi-anabranch reach were adopted, and the distances from the five positions to the left bank of the upstream main channel were 1/6B, 1/3B, 1/2B, 2/3B, and 5/6B (B is the width of the upstream main channel, respectively. The longitudinal velocities and pollutant concentrations in the seven branches were measured. The planar flow field and mixing characteristics of pollutants from the bottom to the surface in the multi-anabranch river were obtained and analyzed. The results show that the pollutant release positions are the main influencing factors in the pollutant transport process, and the diversion points and pollutant release positions jointly influence the percentage ratios of the pollutant fluxes in branches B1, B2, and B3 to the pollutant flux in the upstream main channel.

  10. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

  11. Steam generator tube failures

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  12. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

    Directory of Open Access Journals (Sweden)

    Jean-Claude Mollet

    2013-03-01

    Full Text Available The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

  13. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth.

    Science.gov (United States)

    Mollet, Jean-Claude; Leroux, Christelle; Dardelle, Flavien; Lehner, Arnaud

    2013-03-07

    The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

  14. Braided rivers, lakes and sabkhas of the upper Triassic Cifuncho formation, Atacama region, Chile

    Science.gov (United States)

    Suárez, M.; Bell, C. M.

    1994-01-01

    A 1,000-m-thickness of Upper Triassic (to possibly Hettangian) sediments of the Cifuncho Formation are exposed in the coastal Cordillera of the Atacama Region, Chile. These coarse-grained clastic terrigenous strata are interpreted as the deposits of braided rivers, ephemeral lakes, sabkhas and volcaniclastic alluvial fans. They include conglomerates, pebbly sandstones, fine to medium-grained sandstones and thin, finely-laminated limestones. Halite hopper-casts are abundant in sandstones near the top of the section. Approximately 90% of the clastic detritus was derived from an upper Paleozoic metasedimentary accretionary complex located to the west. Andesitic debris flow and pyroclastic flow deposits occur near the base of the sequence. Isolated tuff intercalations and an ignimbritic lava flow occur higher in the section. The great thickness of coarse-grained and ill-sorted clastic sediments suggests deposition in an actively subsiding basin, probably a graben, adjacent to rising highlands. Overlying Hettangian-Sinemurian marine sediments were deposited by a transgression which occurred during a world-wide lowstand. This suggests that thermal subsidence followed the Triassic rifting.

  15. GoldenBraid 2.0: a comprehensive DNA assembly framework for plant synthetic biology.

    Science.gov (United States)

    Sarrion-Perdigones, Alejandro; Vazquez-Vilar, Marta; Palací, Jorge; Castelijns, Bas; Forment, Javier; Ziarsolo, Peio; Blanca, José; Granell, Antonio; Orzaez, Diego

    2013-07-01

    Plant synthetic biology aims to apply engineering principles to plant genetic design. One strategic requirement of plant synthetic biology is the adoption of common standardized technologies that facilitate the construction of increasingly complex multigene structures at the DNA level while enabling the exchange of genetic building blocks among plant bioengineers. Here, we describe GoldenBraid 2.0 (GB2.0), a comprehensive technological framework that aims to foster the exchange of standard DNA parts for plant synthetic biology. GB2.0 relies on the use of type IIS restriction enzymes for DNA assembly and proposes a modular cloning schema with positional notation that resembles the grammar of natural languages. Apart from providing an optimized cloning strategy that generates fully exchangeable genetic elements for multigene engineering, the GB2.0 toolkit offers an evergrowing open collection of DNA parts, including a group of functionally tested, premade genetic modules to build frequently used modules like constitutive and inducible expression cassettes, endogenous gene silencing and protein-protein interaction tools, etc. Use of the GB2.0 framework is facilitated by a number of Web resources that include a publicly available database, tutorials, and a software package that provides in silico simulations and laboratory protocols for GB2.0 part domestication and multigene engineering. In short, GB2.0 provides a framework to exchange both information and physical DNA elements among bioengineers to help implement plant synthetic biology projects.

  16. 3D flexible NiTi-braided elastomer composites for smart structure applications

    Science.gov (United States)

    Heller, L.; Vokoun, D.; Šittner, P.; Finckh, H.

    2012-04-01

    While outstanding functional properties of thin NiTi wires are nowadays well recognized and beneficially utilized in medical NiTi devices, development of 2D/3D wire structures made out of these NiTi wires remains challenging and mostly unexplored. The research is driven by the idea of creating novel 2D/3D smart structures which inherit the functional properties of NiTi wires and actively utilize geometrical deformations within the structure to create new/improved functional properties. Generally, textile technology provides attractive processing methods for manufacturing 2D/3D smart structures made out of NiTi wires. Such structures may be beneficially combined with soft elastomers to create smart deformable composites. Following this route, we carried out experimental work focused on development of 3D flexible NiTi-braided elastomer composites involving their design, laboratory manufacture and thermomechanical testing. We describe the manufacturing technology and structural properties of these composites; and perform thermomechanical tests on the composites, focusing particularly on quasistatic tensile properties, energy absorption, damping and actuation under tensile loading. Functional thermomechanical properties of the composites are discussed with regard to the mechanical properties of the components and architecture of the composites. It is found that the composites indeed inherit all important features of the thermomechanical behavior of NiTi wires but, due to their internal architecture, outperform single NiTi wires in some features such as the magnitude of recoverable strain, superelastic damping capacity and thermally induced actuation strain.

  17. Pyrotechnic Tubing Connector

    Science.gov (United States)

    Graves, Thomas J.; Yang, Robert A.

    1988-01-01

    Tool forms mechanical seal at joint without levers or hydraulic apparatus. Proposed tool intended for use in outer space used on Earth by heavily garbed workers to join tubing in difficult environments. Called Pyrotool, used with Lokring (or equivalent) fittings. Piston slides in cylinder when pushed by gas from detonating pyrotechnic charge. Impulse of piston compresses fittings, sealing around butting ends of tubes.

  18. Neural Tube Defects

    Science.gov (United States)

    ... pregnancies each year in the United States. A baby’s neural tube normally develops into the brain and spinal cord. ... fluid in the brain. This is called hydrocephalus. Babies with this condition are treated with surgery to insert a tube (called a shunt) into the brain. The shunt ...

  19. Glacial conditioning of stream position and flooding in the braid plain of the Exit Glacier foreland, Alaska

    Science.gov (United States)

    Curran, Janet H.; Loso, Michael G.; Williams, Haley B.

    2017-09-01

    Flow spilling out of an active braid plain often signals the onset of channel migration or avulsion to previously occupied areas. In a recently deglaciated environment, distinguishing between shifts in active braid plain location, considered reversible by fluvial processes at short timescales, and more permanent glacier-conditioned changes in stream position can be critical to understanding flood hazards. Between 2009 and 2014, increased spilling from the Exit Creek braid plain in Kenai Fjords National Park, Alaska, repeatedly overtopped the only access road to the popular Exit Glacier visitor facilities and trails. To understand the likely cause of road flooding, we consider recent processes and the interplay between glacier and fluvial system dynamics since the maximum advance of the Little Ice Age, around 1815. Patterns of temperature and precipitation, the variables that drive high streamflow via snowmelt, glacier meltwater runoff, and rainfall, could not fully explain the timing of road floods. Comparison of high-resolution topographic data between 2008 and 2012 showed a strong pattern of braid plain aggradation along 3 km of glacier foreland, not unexpected at the base of mountainous glaciers and likely an impetus for channel migration. Historically, a dynamic zone follows the retreating glacier in which channel positions shift rapidly in response to changes in the glacier margin and fresh morainal deposits. This period of paraglacial adjustment lasts one to several decades at Exit Glacier. Subsequently, as moraine breaches consolidate and lock the channel into position, and as the stream regains the lower-elevation valley center, upper-elevation surfaces are abandoned as terraces inaccessible by fluvial processes for timescales of decades to centuries. Where not constrained by these terraces and moraines, the channel is free to migrate, which in this aggradational setting generates an alluvial fan at the breach of the final prominent moraine. The position of

  20. Molybdenum Tube Characterization report

    Energy Technology Data Exchange (ETDEWEB)

    Beaux II, Miles Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-07

    Chemical vapor deposition (CVD) techniques have been utilized to produce free-standing molybdenum tubes with the end goal of nuclear fuel clad applications. In order to produce tubes with properties desirable for this application, deposition rates were lowered requiring long deposition durations on the order of 50 hours. Standard CVD methods as well as fluidized-bed CVD (FBCVD) methods were applied towards these objectives. Characterization of the tubes produced in this manner revealed material suitable for fuel clad applications, but lacking necessary uniformity across the length of the tubes. The production of freestanding Mo tubes that possess the desired properties across their entire length represents an engineering challenge that can be overcome in a next iteration of the deposition system.

  1. Supramolecular Polymers

    Science.gov (United States)

    Stupp, S. I.; Keser, M.; Huggins, K. E.; Tew, G.; Li, L. S.; Whitaker, C.

    1997-03-01

    An interesting target in polymer science is to find pathways to highly regular supramolecular units with dimensions similar to those of high molar mass linear or hyperbranched polymers. These units lack a polymeric backbone but could serve as precursors to shape invariant covalent polymers analogous to folded proteins. We are pursuing access to these polymers with designed molecules programmed to assemble into nanostructures of regular shape and dimension. We have discovered systems of miniaturized triblock copolymers that yield supramolecular polymers. These supramolecular polymers are shaped as mushroom nanostructures, and form materials with interesting surface and optical properties. Molecular modeling indicates that a balance of aggregation and hard core repulsive forces among structural units may be responsible for the formation of these supramolecular polymers.

  2. Standard Guide for Testing Polymer Matrix Composite Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This guide summarizes the application of ASTM standard test methods (and other supporting standards) to continuous-fiber reinforced polymer matrix composite materials. The most commonly used or most applicable ASTM standards are included, emphasizing use of standards of Committee D30 on Composite Materials. 1.2 This guide does not cover all possible standards that could apply to polymer matrix composites and restricts discussion to the documented scope. Commonly used but non-standard industry extensions of test method scopes, such as application of static test methods to fatigue testing, are not discussed. A more complete summary of general composite testing standards, including non-ASTM test methods, is included in the Composite Materials Handbook (MIL-HDBK-17). Additional specific recommendations for testing textile (fabric, braided) composites are contained in Guide D6856. 1.3 This guide does not specify a system of measurement; the systems specified within each of the referenced standards shall appl...

  3. Nanoscale Study of Polymer Dynamics.

    Science.gov (United States)

    Keshavarz, Masoumeh; Engelkamp, Hans; Xu, Jialiang; Braeken, Els; Otten, Matthijs B J; Uji-I, Hiroshi; Schwartz, Erik; Koepf, Matthieu; Vananroye, Anja; Vermant, Jan; Nolte, Roeland J M; De Schryver, Frans; Maan, Jan C; Hofkens, Johan; Christianen, Peter C M; Rowan, Alan E

    2016-01-26

    The thermal motion of polymer chains in a crowded environment is anisotropic and highly confined. Whereas theoretical and experimental progress has been made, typically only indirect evidence of polymer dynamics is obtained either from scattering or mechanical response. Toward a complete understanding of the complicated polymer dynamics in crowded media such as biological cells, it is of great importance to unravel the role of heterogeneity and molecular individualism. In the present work, we investigate the dynamics of synthetic polymers and the tube-like motion of individual chains using time-resolved fluorescence microscopy. A single fluorescently labeled polymer molecule is observed in a sea of unlabeled polymers, giving access to not only the dynamics of the probe chain itself but also to that of the surrounding network. We demonstrate that it is possible to extract the characteristic time constants and length scales in one experiment, providing a detailed understanding of polymer dynamics at the single chain level. The quantitative agreement with bulk rheology measurements is promising for using local probes to study heterogeneity in complex, crowded systems.

  4. Development of Braided Basalt FRP Rebar for Reinforcement of Concrete Structures

    OpenAIRE

    Antonopoulou, Sofia; McNally, Ciaran; Byrne, Greg

    2016-01-01

    In recent years, the development and use of Fibre Reinforced Polymer composite materials in infrastructure have gained increasing attention worldwide. More specifically, natural mineral fibres such as basalt are currently being developed and are showing promising properties. Within an appropriate polymer matrix, their use as reinforcement in concrete structures offers performance benefits related to their environmentally friendly and non-corrodible nature. In particular, BFRPs have the potent...

  5. Isolated Fallopian Tube Torsion

    Directory of Open Access Journals (Sweden)

    S. Kardakis

    2013-01-01

    Full Text Available Isolated torsion of the Fallopian tube is a rare gynecological cause of acute lower abdominal pain, and diagnosis is difficult. There are no pathognomonic symptoms; clinical, imaging, or laboratory findings. A preoperative ultrasound showing tubular adnexal masses of heterogeneous echogenicity with cystic component is often present. Diagnosis can rarely be made before operation, and laparoscopy is necessary to establish the diagnosis. Unfortunately, surgery often is performed too late for tube conservation. Isolated Fallopian tube torsion should be suspected in case of acute pelvic pain, and prompt intervention is necessary.

  6. Invasive riparian vegetation response to flow regimes and flood pulses in a braided river floodplain.

    Science.gov (United States)

    Caruso, Brian S; Pithie, Callum; Edmondson, Laura

    2013-08-15

    This study evaluated flow regimes and flood pulse characteristics, and their influences on invasive riparian vegetation, in a free-flowing braided river in the Southern Alps, South Island, New Zealand. A 46-year gauged flow record was used to evaluate 67 flow metrics for the Ahuriri River, and five sets of colour aerial photographs over 20 years (1991-2011) were analysed to quantify temporal and spatial changes in vegetation (crack willow, Russell lupin, and grassland). The correlation between flow metrics and vegetation class cover for each aerial photo interval was analysed, and multiple regression models were developed. Significant changes in different invasive vegetation classes were found, including cover, number and sizes of patches, and distances from patches to primary channels. In addition to infrequent large floods, specific characteristics of small floods, high flows, low/baseflows, and extreme low flows had influences on different vegetation classes. Key metrics that appear to drive changes in cover and provide a useful multiple regression model include the largest flood peak, frequency of floods, and the time since the last flood for each air photo interval. Up to 25% of invasive vegetation cover was removed and bare substrate increased after the largest flood on record (approximately 50-year flood), and the amount of vegetation cover is highly variable over time and space. Within approximately six years, however, the proportion of vegetation recovered to pre-flood levels. The study reach appears to demonstrate the "shifting-mosaic steady state" conceptual model of riverine floodplains, where the total proportion of substrate, vegetation and water remain relatively constant over long time periods. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Tracheostomy tube - eating

    Science.gov (United States)

    Trach - eating ... take your first bites. Certain factors may make eating or swallowing harder, such as: Changes in the ... easier to swallow. Suction the tracheostomy tube before eating. This will keep you from coughing while eating, ...

  8. Bull Moose Tube Company

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against the Bull Moose Tube Company, a business located at 1819 Clarkson Road, Chesterfield, MO, 63017, for alleged violations at the facility located at 406 East Industrial Drive,

  9. Tube-Forming Assays.

    Science.gov (United States)

    Brown, Ryan M; Meah, Christopher J; Heath, Victoria L; Styles, Iain B; Bicknell, Roy

    2016-01-01

    Angiogenesis involves the generation of new blood vessels from the existing vasculature and is dependent on many growth factors and signaling events. In vivo angiogenesis is dynamic and complex, meaning assays are commonly utilized to explore specific targets for research into this area. Tube-forming assays offer an excellent overview of the molecular processes in angiogenesis. The Matrigel tube forming assay is a simple-to-implement but powerful tool for identifying biomolecules involved in angiogenesis. A detailed experimental protocol on the implementation of the assay is described in conjunction with an in-depth review of methods that can be applied to the analysis of the tube formation. In addition, an ImageJ plug-in is presented which allows automatic quantification of tube images reducing analysis times while removing user bias and subjectivity.

  10. Tube Alinement for Machining

    Science.gov (United States)

    Garcia, J.

    1984-01-01

    Tool with stepped shoulders alines tubes for machining in preparation for welding. Alinement with machine tool axis accurate to within 5 mils (0.13mm) and completed much faster than visual setup by machinist.

  11. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry

    2012-01-01

    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  12. Aeronautical tubes and pipes

    Science.gov (United States)

    Beauclair, N.

    1984-12-01

    The main and subcomponent French suppliers of aircraft tubes and pipes are discussed, and the state of the industry is analyzed. Quality control is essential for tubes with regard to their i.d. and metallurgical compositions. French regulations do not allow welded seam tubes in hydraulic circuits unless no other form is available, and then rustproofed steel must be installed. The actual low level of orders for any run of tubes dictates that the product is only one of several among the manufacturers' line. Automation, both in NDT and quality control, assures that the tubes meet specifications. A total of 10 French companies participate in the industry, serving both civil and military needs, with some companies specializing only in titanium, steel, or aluminum materials. Concerns wishing to enter the market must upgrade their equipment to meet the higher aeronautical specifications and be prepared to furnish tubes and pipes that serve both functional and structural purposes simultaneously. Additionally, pipe-bending machines must also perform to tight specifications. Pipes can range from 0.2 mm exterior diameter to 40 mm, with wall thicknesses from 0.02 mm to 3 mm. A chart containing a list of manufacturers and their respective specifications and characteristics is presented, and a downtrend in production with reduction of personnel is noted.

  13. Spherical tube hypersurfaces

    CERN Document Server

    Isaev, Alexander

    2011-01-01

    We examine Levi non-degenerate tube hypersurfaces in complex linear space which are "spherical," that is, locally CR-equivalent to the real hyperquadric. Spherical hypersurfaces are characterized by the condition of the vanishing of the CR-curvature form, so such hypersurfaces are flat from the CR-geometric viewpoint. On the other hand, such hypersurfaces are also of interest from the point of view of affine geometry. Thus our treatment of spherical tube hypersurfaces in this book is two-fold: CR-geometric and affine-geometric. As the book shows, spherical tube hypersurfaces possess remarkable properties. For example, every such hypersurface is real-analytic and extends to a closed real-analytic spherical tube hypersurface in complex space. One of our main goals is to provide an explicit affine classification of closed spherical tube hypersurfaces whenever possible. In this book we offer a comprehensive exposition of the theory of spherical tube hypersurfaces, starting with the idea proposed in the pioneering...

  14. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  15. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  16. Polymer Chemistry

    Science.gov (United States)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  17. Rubber Bands as Model Polymers in Couette Flow

    Science.gov (United States)

    Dunstan, Dave E.

    2008-01-01

    We present a simple device for demonstrating the essential aspects of polymers in flow in the classroom. Rubber bands are used as a macroscopic model of polymers to allow direct visual observation of the flow-induced changes in orientation and conformation. A transparent Perspex Couette cell, constructed from two sections of a tube, is used to…

  18. Double fixation of displaced patella fractures using bioabsorbable cannulated lag screws and braided polyester suture tension bands.

    Science.gov (United States)

    Qi, Li; Chang, Cao; Xin, Tang; Xing, Pei Fu; Tianfu, Yang; Gang, Zhong; Jian, Li

    2011-10-01

    To evaluate the effectiveness and safety of a new double fixation technique for displaced patellar fractures using bioabsorbable cannulated lag screws and braided polyester suture tension bands. Fifteen patients (mean age of 46.2 years) with displaced transverse or comminuted patella fractures were enrolled in this prospective study. All of the patients were treated via the open reduction internal fixation (ORIF) procedure using bioabsorbable cannulated lag screws and braided polyester suture tension bands. The patients were followed post-surgery to evaluate (1) the time required for radiographic bone union, (2) the knee joint range of motion at the time of radiographic bone union, (3) the degree of pain assessed using the visual analogue scale (VAS), (4) the function of the knee using the Lysholm score and (5) the presence of any additional complications from the surgery. All of the patients were followed post-treatment for more than 1 year (range, 12-19 months; mean post-treatment follow up time, 14 months). The bone union of the fractures as seen radiographically occurred approximately 3 months from surgery in all cases without implant failure or redisplacement of the fractured site. The mean knee joint range of motion was from 0 to 134.6°, and the mean VAS score was 0.7 at the time of bone union. The mean Lysholm scores at the time of bone union and 12 months post-surgery were 86.7 and 95.7, respectively. No postoperative complications, such as infection, dislocation or breakage of the implants, were observed. Moreover, all of the patients returned to their previous activity level. This new double fixation technique using bioabsorbable cannulated lag screws and braided polyester suture tension bands resulted in satisfactory outcomes for patella fractures without any obvious complications. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Morphological analysis of zirconium nuclear fuel retaining rods braided with SiC: Quality assurance and defect identification

    Energy Technology Data Exchange (ETDEWEB)

    Glazoff, Michael V., E-mail: Michael.Glazoff@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3710 (United States); Hiromoto, Robert; Tokuhiro, Akira [University of Idaho, CAES, Dept. of Nuclear Engineering, Idaho Falls, ID 83401 (United States)

    2014-08-01

    Highlights: • The stability of materials under extreme conditions is an important issue for the safety of nuclear reactors. • To improve zircaloys’ thermal stability in off-normal conditions, coating of SiC filaments is considered because silicon carbide possesses remarkable inertness at high temperatures. • Mathematical morphology was used for automatic defect identification in Zircaloy-4 rods braided with the layer of SiC filament. • The original mathematical morphology algorithms allowing solving the problem of quality assurance were developed. • In nuclear industry, such algorithms are used for the first time. - Abstract: In the after-Fukushima world, the stability of materials under extreme conditions is an important issue for the safety of nuclear reactors. Among the methods explored currently to improve zircaloys’ thermal stability in off-normal conditions, using a protective coat of the SiC filaments is considered because silicon carbide is well known for its remarkable chemical inertness at high temperatures. A typical SiC fiber contains ∼50,000 individual filaments of 5–10 μm in diameter. In this paper, an effort was made to develop and apply mathematical morphology to the process of automatic defect identification in Zircaloy-4 rods braided with the protective layer of the silicon carbide filament. However, the issues of the braiding quality have to be addressed to ensure its full protective potential. We present the original mathematical morphology algorithms that allow solving this problem of quality assurance successfully. In nuclear industry, such algorithms are used for the first time, and could be easily generalized to the case of automated continuous monitoring for defect identification in the future.

  20. Assessment of a numerical model to reproduce event‐scale erosion and deposition distributions in a braided river

    Science.gov (United States)

    Measures, R.; Hicks, D. M.; Brasington, J.

    2016-01-01

    Abstract Numerical morphological modeling of braided rivers, using a physics‐based approach, is increasingly used as a technique to explore controls on river pattern and, from an applied perspective, to simulate the impact of channel modifications. This paper assesses a depth‐averaged nonuniform sediment model (Delft3D) to predict the morphodynamics of a 2.5 km long reach of the braided Rees River, New Zealand, during a single high‐flow event. Evaluation of model performance primarily focused upon using high‐resolution Digital Elevation Models (DEMs) of Difference, derived from a fusion of terrestrial laser scanning and optical empirical bathymetric mapping, to compare observed and predicted patterns of erosion and deposition and reach‐scale sediment budgets. For the calibrated model, this was supplemented with planform metrics (e.g., braiding intensity). Extensive sensitivity analysis of model functions and parameters was executed, including consideration of numerical scheme for bed load component calculations, hydraulics, bed composition, bed load transport and bed slope effects, bank erosion, and frequency of calculations. Total predicted volumes of erosion and deposition corresponded well to those observed. The difference between predicted and observed volumes of erosion was less than the factor of two that characterizes the accuracy of the Gaeuman et al. bed load transport formula. Grain size distributions were best represented using two φ intervals. For unsteady flows, results were sensitive to the morphological time scale factor. The approach of comparing observed and predicted morphological sediment budgets shows the value of using natural experiment data sets for model testing. Sensitivity results are transferable to guide Delft3D applications to other rivers. PMID:27708477

  1. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home > NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  2. Gastrostomy feeding tube - pump - child

    Science.gov (United States)

    ... tube feeding; PEG tube care; Feeding - gastrostomy tube - pump; G-tube - pump; Gastrostomy button - pump; Bard Button - pump; MIC-KEY - pump ... Gather supplies: Feeding pump (electronic or battery powered) Feeding ... pump (includes a feeding bag, drip chamber, roller clamp, ...

  3. Composite Coiled Tubing for Extended Reach in Horizontal Oil Wells

    DEFF Research Database (Denmark)

    Costache, Andrei; Berggreen, Christian

    2017-01-01

    Conventional steel coiled tubing cannot reach along the entire length of very long horizontal oil wells. A lighter and more buoyant coiled tube is made possible using composite materials. The high stiffness to weight ratio of fiber reinforced polymers, coupled with a lower coefficient of friction......, has the potential of greatly extending the reach in horizontal oil wells. This study shows how to design composite coiled tubing and gives a comprehensive discussion about the most influential parameters. Several solutions, using glass-fiber and carbon are considered. Finite element models are used...... to calculate the buckling loads and the corresponding interlaminar stresses. The very positive results obtained during this study show that composite coiled tubing systems are vastly superior to their steel counterparts, and that in the future, these will become the new industry standard....

  4. Polymer Diffusion in the Presence of Nanoparticles

    Science.gov (United States)

    Winey, Karen

    2014-03-01

    The center-of-mass diffusion of polymers within a polymer melt proceeds by the mechanism of reptation wherein the polymer is confined to a tube that is defined by neighboring entanglements and moves along its contour. Polymer diffusion is perturbed when the melt contains nanoparticles that are comparable in size to the radius of gyration (Rg) of the polymers. Within this talk, we will present tracer diffusion coefficients (D) results for three types of nanocomposite: spherical nanoparticles with surface functionalization, spherical nanoparticles with brushes, and cylindrical nanoparticles (aspect ratio = 5 to 50). When functionalized spherical nanoparticles have neutral or attractive interactions with the polymer matrix, a monotonic decrease in the diffusion coefficient is observed across a wide range of polymer molecular weight, nanoparticle size, and nanoparticle concentration. These data collapse onto a master curve when plotted as D normalized by the diffusion coefficient into a neat homopolymer (D/Do) versus our confinement parameter defined as the interparticle distance divided by 2Rg (ID/2Rg). Polymer diffusion in systems with grafted spherical nanoparticles exhibit the same D/Do versus ID/2Rg, when ID accounts for the extent to which the tracer polymer penetrates the polymer brush. For various cylindrical nanoparticles D/Do versus nanoparticle concentration exhibits a minimum when 2Rg is both larger than the nanoparticle diameter and smaller than the nanoparticle length. Complimentary molecular dynamics simulations and neutron scattering results will also be presented.

  5. Branched polymers on branched polymers

    OpenAIRE

    Durhuus, Bergfinnur; Jonsson, Thordur

    1996-01-01

    We study an ensemble of branched polymers which are embedded on other branched polymers. This is a toy model which allows us to study explicitly the reaction of a statistical system on an underlying geometrical structure, a problem of interest in the study of the interaction of matter and quantized gravity. We find a phase transition at which the embedded polymers begin to cover the basis polymers. At the phase transition point the susceptibility exponent $\\gamma$ takes the value 3/4 and the ...

  6. Conducting Polymers

    Indian Academy of Sciences (India)

    potential of the monomer would be less than that of the dimer, which would in turn be less than that of the polymer. Hence, the polymer generated by this oxidative .... glucose and galactose biosensors based on a silicon chip employing polypyrrole have in fact been developed by several companies. These types of sensors ...

  7. Conducting Polymers

    Indian Academy of Sciences (India)

    polymer backbone), exhibit semiconducting behavior. The discovery of dopingl led to a further dramatic increase in the conductivity of such conjugated polymers to values as ..... CERF's Comments on Modem Science. • If it's incomprehensible, it's mathematics. • If it doesn't make sense, it's either economics or psychology.

  8. Polymers & People

    Science.gov (United States)

    Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

    2004-01-01

    Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

  9. Categorising YouTube

    Directory of Open Access Journals (Sweden)

    Thomas Mosebo Simonsen

    2011-09-01

    Full Text Available This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC of YouTube. The article investigates the construction of navigationprocesses on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within the interacting relationship of new and old genres are discussed. It is argued that the utility of a conventional categorical system is primarily of analytical and theoretical interest rather than as a practical instrument.

  10. Geiger-Muller tubes

    Energy Technology Data Exchange (ETDEWEB)

    Gair, S.A.; Copleston, R.E.

    1991-01-16

    A Geiger-Muller tube designed for use in an environment (for example, mounted on a rock drill) where subjected to mechanical shock and vibration has a tensioned anode wire secured by welding to securement members between first and second mounts at opposite ends of the tube envelope. The wire tension is adjusted to a high value with a screwable-adjustment means which is locked eg. by a spot-weld or by a locking nut, in the adjusted position, so that the natural frequency of the vibration of the tensioned wire does not resonate with (and may be much higher than) the frequencies to which the tube is subjected in use. The wire frequency is typically in excess of 400Hz and even 500Hz. The adjustment means may be included in the mount via which the envelope is evacuated and back-filled with the ionizible gas, and a gas-tight seal can be provided around this part of the mount, for example by sealing off the gas pump tube. However the adjustment means may be designed into another part of the tube, for example using telescopic parts of the envelope whose sliding junction is made gas tight with a flexible seal. (author).

  11. A radio frequency tracing experiment of bedload transport in a small braided mountain stream

    Science.gov (United States)

    Liebault, F.; Chapuis, M.; Bellot, H.; Deschatres, M.

    2009-04-01

    Radio frequency identification technology is used for monitoring the displacement of coarse particles in streams since the beginning of the 2000s. Passive integrated transponders (PIT tags) are small, cheap and long-lasting electronic tags that can be programmed with their own identification code. Initially used in environmental research for animal tracking, they have been deployed successfully in a variety of fluvial environments for coarse sediment tracing. Pioneering studies conducted in both semiarid and humid small upland streams with low intensity bedload transport gave recovery rates above 85% (Nichols 2004; Lamarre et al. 2005). Here we present an experiment of radio frequency sediment tracing implemented on a small braided mountain stream with a high intensity bedload transport and a wide active channel (mean active channel width: about 20 m). The study site is the Bouinenc Torrent, a tributary to the Bléone River in SE France that drains a 39 km² mountainous drainage basin of the Southern Prealps. In spring 2008, we deployed 451 tracers with b-axis ranging from 23 to 520 mm. Tracers were deployed along 8 cross sections located in the upstream part of the lowest 2.3 km of the stream. We developed a RFID detection system composed of an antenna and a reader unit; this system is characterized by a range of detection of 80 cm in optimal configuration. Two small intensity flow events occurred in June 2008 and entrained the tracers deployed in the most active part of the active channel. We mapped the position of the displaced tracers with a dGPS in July 2008. We obtained an overall recovery rate of 88%. The recovery rate calculated for the active tracers (those that were displaced after the flow events) was 76%. The projection of the tracer dispersion cloud on high resolution aerial photographs obtained with a drone allows us to calculate the distance of transport for each tracer. Mean and maximal distances of transport were respectively 796 m (+/- 53 m) and 2

  12. Braided Carbon Fiber Rope Flow Characteristics. Degree awarded by Utah Univ.

    Science.gov (United States)

    Heman, J. R. C.; McCool, A. (Technical Monitor)

    2000-01-01

    I am submitting the following technical subject for consideration as a thesis topic for the master degree: The reusable solid rocket motor (RSRM) nozzle internal joints are being evaluated for the incorporation of a carbon fiber rope (CFR) as a thermal barrier. The CFR is approximately 0.260 in. diameter and is composed of approximately 12,000 carbon fibers, woven in ten sheaths or layers. The CFR is manufactured by a sub-tier vendor and subsequently several of its manufacturing details are proprietary to that vendor. The CFR design intent is to prevent hot motor combustion products and slag from intruding into the joint scaling area while still approaching a vented joint design to avoid the detriments of gas jet impingement. As a member of the Heat Transfer section at Thiokol Propulsion, two main goals exist as part of this NASA funded design effort: (1) development of flow model through the CFR and (2) development of a heat transfer model through the CFR. While both models are needed and most probably interrelated, the gas flow model is being targeted as the subject matter. Essentially, the topic would be "Modeling of Gas Flow through a Braided Carbon Fiber Rope". An AIAA journal or conference paper is being considered through Thiokol/NASA as well. A sub-scale CFR flow test fixture was designed to simulate the relative levels of CFR compression. The test fixture provides the means to measure gas mass flow rate upstream of the CFR and the pressure and temperature both upstream and downstream of the CFR. The test fixture was designed to eliminate the possibility of dynamic gapping at the CFR location and provide minimal flow resistance to ambient for gases exiting the rope. The data collected in the experiment will be evaluated to define a permeability/flow resistance model. Two possibilities exist for the flow characteristics through the CFR from choked flow to strictly friction driven. A test matrix for evaluating the CFR has been compiled, which addresses both

  13. Meso-Scale Progressive Damage Behavior Characterization of Triaxial Braided Composites under Quasi-Static Tensile Load

    Science.gov (United States)

    Ren, Yiru; Zhang, Songjun; Jiang, Hongyong; Xiang, Jinwu

    2017-08-01

    Based on continuum damage mechanics (CDM), a sophisticated 3D meso-scale finite element (FE) model is proposed to characterize the progressive damage behavior of 2D Triaxial Braided Composites (2DTBC) with 60° braiding angle under quasi-static tensile load. The modified Von Mises strength criterion and 3D Hashin failure criterion are used to predict the damage initiation of the pure matrix and fiber tows. A combining interface damage and friction constitutive model is applied to predict the interface damage behavior. Murakami-Ohno stiffness degradation scheme is employed to predict the damage evolution process of each constituent. Coupling with the ordinary and translational symmetry boundary conditions, the tensile elastic response including tensile strength and failure strain of 2DTBC are in good agreement with the available experiment data. The numerical results show that the main failure modes of the composites under axial tensile load are pure matrix cracking, fiber and matrix tension failure in bias fiber tows, matrix tension failure in axial fiber tows and interface debonding; the main failure modes of the composites subjected to transverse tensile load are free-edge effect, matrix tension failure in bias fiber tows and interface debonding.

  14. Morphological Analysis of Zirconium Nuclear Fuel Retaining Rods Braided with SiC: Quality Assurance and Defect Identification

    Energy Technology Data Exchange (ETDEWEB)

    Michael V Glazoff; Robert Hiromoto; Akira Tokuhiro

    2014-08-01

    In the after-Fukushima world, the stability of materials under extreme conditions is an important issue for the safety of nuclear reactors. Among the methods explored currently to improve zircaloys’ thermal stability in off-normal conditions, using a protective coat of the SiC filaments is considered because silicon carbide is well known for its remarkable chemical inertness at high temperatures. A typical SiC fiber contains ~50,000 individual filaments of 5 – 10 µm in diameter. In this paper, an effort was made to develop and apply mathematical morphology to the process of automatic defect identification in Zircaloy-4 rods braided with the protective layer of the silicon carbide filament. However, the issues of the braiding quality have to be addressed to ensure its full protective potential. We present the original mathematical morphology algorithms that allow solving this problem of quality assurance successfully. In nuclear industry, such algorithms are used for the first time, and could be easily generalized to the case of automated continuous monitoring for defect identification in the future.

  15. Numerical and Experimental Investigation of the Hydrostatic Performance of Fibre Reinforced Tubes

    Science.gov (United States)

    Pavlopoulou, S.; Roy, S. S.; Gautam, M.; Bradshaw, L.; Potluri, P.

    2017-04-01

    The increasing demands in subsea industry such as oil and gas, led to a rapidly growing need for the use of advanced, high performance, lightweight materials such as composite materials. E-glass fibre laminated pre-preg, filament wound and braided tubes were tested to destruction under hydrostatic external pressure in order to study their buckling and crushing behaviour. Different fibre architectures and wind angles were tested at a range of wall thicknesses highlighting the advantage that hoop reinforcement offers. The experimental results were compared with theoretical predictions obtained from classic laminate theory and finite element analysis (ABAQUS) based on the principal that the predominant failure mode was buckling. SEM analysis was further performed to investigate the resulting failure mechanisms, indicating that the failure mechanisms can be more complex with a variety of observed modes taking place such as fibre fracture, delamination and fibre-matrix interface failure.

  16. A New Resonance Tube

    Science.gov (United States)

    Bates, Alan

    2017-01-01

    The measurement of the speed of sound in air with the resonance tube is a popular experiment that often yields accurate results. One approach is to hold a vibrating tuning fork over an air column that is partially immersed in water. The column is raised and lowered in the water until the generated standing wave produces resonance: this occurs at…

  17. Cladding tube manufacturing technology

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R. [Kraftwerk Union AG, Mulheim (Germany); Jeong, Y.H.; Baek, B.J.; Kim, K.H.; Kim, S.J.; Choi, B.K.; Kim, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-04-01

    This report gives an overview of the manufacturing routine of PWR cladding tubes. The routine essentially consists of a series of deformation and annealing processes which are necessary to transform the ingot geometry to tube dimensions. By changing shape, microstructure and structure-related properties are altered simultaneously. First, a short overview of the basics of that part of deformation geometry is given which is related to tube reducing operations. Then those processes of the manufacturing routine which change the microstructure are depicted, and the influence of certain process parameters on microstructure and material properties are shown. The influence of the resulting microstructure on material properties is not discussed in detail, since it is described in my previous report 'Alloy Development for High Burnup Cladding.' Because of their paramount importance still up to now, and because manufacturing data and their influence on properties for other alloys are not so well established or published, the descriptions are mostly related to Zry4 tube manufacturing, and are only in short for other alloys. (author). 9 refs., 46 figs.

  18. Jejunostomy feeding tube

    Science.gov (United States)

    ... skin for redness, odor, pain, puss, or swelling. Make sure the stitches are still in place. Use the clean towel or Q-tip to clean the skin around the J-tube 1 to 3 times a day with mild soap and water. Try to remove any drainage or crusting on ...

  19. Polymer flooding

    Energy Technology Data Exchange (ETDEWEB)

    Littmann, W.

    1988-01-01

    This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past, polymer flooding was mainly the subject of research. The results of this research are spread over a vast number of single publications, making it difficult for someone who has not kept up-to-date with developments during the last 10-15 years to judge the suitability of polymer flooding to a particular field case. This book tries to fill that gap. An indispensable book for reservoir engineers, production engineers and lab. technicians within the petroleum industry.

  20. Organometallic Polymers.

    Science.gov (United States)

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  1. Fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro

    NARCIS (Netherlands)

    Foek, Dave Lie Sam; Yetkiner, Enver; Ozcan, Mutlu

    Objective: To analyze the fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro. Methods: Roots of human mandibular central incisors were covered with silicone, mimicking the

  2. Drift tubes of Linac 2

    CERN Multimedia

    Photographic Service

    1977-01-01

    Being redied for installation, those at the right are for tank 1, those on the left for tank 2. Contrary to Linac 1, which had drift-tubes supported on stems, here the tubes are suspended, for better mechanical stability.

  3. Connectivity of Multi-Channel Fluvial Systems: A Comparison of Topology Metrics for Braided Rivers and Delta Networks

    Science.gov (United States)

    Tejedor, A.; Marra, W. A.; Addink, E. A.; Foufoula-Georgiou, E.; Kleinhans, M. G.

    2016-12-01

    Advancing quantitative understanding of the structure and dynamics of complex networks has transformed research in many fields as diverse as protein interactions in a cell to page connectivity in the World Wide Web and relationships in human societies. However, Geosciences have not benefited much from this new conceptual framework, although connectivity is at the center of many processes in hydro-geomorphology. One of the first efforts in this direction was the seminal work of Smart and Moruzzi (1971), proposing the use of graph theory for studying the intricate structure of delta channel networks. In recent years, this preliminary work has precipitated in a body of research that examines the connectivity of multiple-channel fluvial systems, such as delta networks and braided rivers. In this work, we compare two approaches recently introduced in the literature: (1) Marra et al. (2014) utilized network centrality measures to identify important channels in a braided section of the Jamuna River, and used the changes of bifurcations within the network over time to explain the overall river evolution; and (2) Tejedor et al. (2015a,b) developed a set of metrics to characterize the complexity of deltaic channel networks, as well as defined a vulnerability index that quantifies the relative change of sediment and water delivery to the shoreline outlets in response to upstream perturbations. Here we present a comparative analysis of metrics of centrality and vulnerability applied to both braided and deltaic channel networks to depict critical channels in those systems, i.e., channels where a change would contribute more substantially to overall system changes, and to understand what attributes of interest in a channel network are most succinctly depicted in what metrics. Marra, W. A., Kleinhans, M. G., & Addink, E. A. (2014). Earth Surface Processes and Landforms, doi:10.1002/esp.3482Smart, J. S., and V. L. Moruzzi (1971), Quantitative properties of delta channel networks

  4. Milestone Report - Demonstrate Braided Material with 3.5 g U/kg Sorption Capacity under Seawater Testing Condition (Milestone M2FT-15OR0310041 - 1/30/2015)

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Christopher James [ORNL; Das, Sadananda [ORNL; Oyola, Yatsandra [ORNL; Mayes, Richard T [ORNL; Gill, Gary [Pacific Northwest National Laboratory (PNNL); Kuo, Li-Jung [Pacific Northwest National Laboratory (PNNL); Wood, Jordana [Pacific Northwest National Laboratory (PNNL)

    2015-01-01

    This report describes work on the successful completion of Milestone M2FT-15OR0310041 (1/30/2015) entitled, Demonstrate braided material with 3.5 g U/kg sorption capacity under seawater testing condition . This effort is part of the Seawater Uranium Recovery Program, sponsored by the U.S. Department of Energy, Office of Nuclear Energy, and involved the development of new adsorbent braided materials at the Oak Ridge National Laboratory (ORNL) and marine testing at the Pacific Northwest National Laboratory (PNNL). ORNL has recently developed four braided fiber adsorbents that have demonstrated uranium adsorption capacities greater than 3.5 g U/kg adsorbent after marine testing at PNNL. The braided adsorbents were synthesized by braiding or leno weaving high surface area polyethylene fibers and conducting radiation-induced graft polymerization of itaconic acid and acrylonitrile monomers onto the braided materials followed by amidoximation and base conditioning. The four braided adsorbents demonstrated capacity values ranging from 3.7 to 4.2 g U/kg adsorbent after 56 days of exposure in natural coastal seawater at 20 oC. All data are normalized to a salinity of 35 psu.

  5. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract Convergence Insufficiency Diabetic Eye Disease Dilated Eye Exam Dry Eye For Kids Glaucoma ...

  6. Enteral Tube Feeding and Pneumonia

    Science.gov (United States)

    Gray, David Sheridan; Kimmel, David

    2006-01-01

    To determine the effects of enteral tube feeding on the incidence of pneumonia, we performed a retrospective review of all clients at our institution who had gastrostomy or jejunostomy tubes placed over a 10-year period. Ninety-three subjects had a history of pneumonia before feeding tube insertion. Eighty had gastrostomy and 13, jejunostomy…

  7. Vortex tube optimization theory

    Energy Technology Data Exchange (ETDEWEB)

    Lewins, Jeffery [Cambridge Univ., Magdalene Coll., Cambridge (United Kingdom); Bejan, Adrian [Duke Univ., Dept. of Mechanical Engineering and Materials Science, Durham, NC (United States)

    1999-11-01

    The Ranque-Hilsch vortex tube splits a single high pressure stream of gas into cold and warm streams. Simple models for the vortex tube combined with regenerative precooling are given from which an optimisation can be undertaken. Two such optimisations are needed: the first shows that at any given cut or fraction of the cold stream, the best refrigerative load, allowing for the temperature lift, is nearly half the maximum loading that would result in no lift. The second optimisation shows that the optimum cut is an equal division of the vortex streams between hot and cold. Bounds are obtainable within this theory for the performance of the system for a given gas and pressure ratio. (Author)

  8. YouTube Physics

    Science.gov (United States)

    Riendeau, Diane

    2012-09-01

    To date, this column has presented videos to show in class, Don Mathieson from Tulsa Community College suggested that YouTube could be used in another fashion. In Don's experience, his students are not always prepared for the mathematic rigor of his course. Even at the high school level, math can be a barrier for physics students. Walid Shihabi, a colleague of Don's, decided to compile a list of YouTube videos that his students could watch to relearn basic mathematics. I thought this sounded like a fantastic idea and a great service to the students. Walid graciously agreed to share his list and I have reproduced a large portion of it below.

  9. Neural tube defects

    Directory of Open Access Journals (Sweden)

    M.E. Marshall

    1981-09-01

    Full Text Available Neural tube defects refer to any defect in the morphogenesis of the neural tube, the most common types being spina bifida and anencephaly. Spina bifida has been recognised in skeletons found in north-eastern Morocco and estimated to have an age of almost 12 000 years. It was also known to the ancient Greek and Arabian physicians who thought that the bony defect was due to the tumour. The term spina bifida was first used by Professor Nicolai Tulp of Amsterdam in 1652. Many other terms have been used to describe this defect, but spina bifida remains the most useful general term, as it describes the separation of the vertebral elements in the midline.

  10. Tube Model for the Elasticity of Entangled Nematic Rubbers

    OpenAIRE

    Kutter, S.; Terentjev, E. M.

    2001-01-01

    Dense rubbery networks are highly entangled polymer systems, with significant topological restrictions for the mobility of neighbouring chains and crosslinks preventing the reptation constraint release. In a mean field approach, entanglements are treated within the famous reptation approach, since they effectively confine each individual chain in a tube-like geometry. We apply the classical ideas of reptation dynamics to calculate the effective rubber-elastic free energy of anisotropic networ...

  11. Blast Loading of Epoxy Panels Using a Shock Tube

    Science.gov (United States)

    Pankow, Mark; Waas, Anthony M.; Bednarcyk, Brett

    2010-01-01

    The high strain rate mechanical response of thin polymer plates has been studied using a modified shock tube. Diagnostics include the pressure-time history of the incident and reflected pulses and the use of digital image correlation (DIC) techniques to extract the time-history of the out-of-plane displacement distribution. Additionally, finite element models have been developed to understand the plate response and to validate and modify plate material constitutive models that have been proposed.

  12. Resorbable fiber-forming polymers for biotextile applications

    CERN Document Server

    Gajjar, Chirag R

    2014-01-01

    This book summarizes the properties and applications of conventional and commercially available fiber-forming, bioresorbable polymers, as well as those currently under study, for use as biotextiles. Factors affecting the performance of these biomaterials are presented, and precautionary measures to reduce premature, hydrolytic degradation during manufacturing and processing are discussed. Because of the structural requirements of medical devices and the technological advancements in synthetic fibers and textile technology, the new field of "Biotextiles" has evolved to exploit the potential of various woven, knitted, braided and non-woven textile structures for biomedical applications. Textile substrates provide certain unique mechanical properties to the medical device and because of an inherently high level of porosity, they can encourage cell growth and promote migration and proliferation. Bioresorbable devices that assist in the repair and regeneration of damaged tissues have in recent years replaced many ...

  13. Diffusion in Tube Dialyzer

    Directory of Open Access Journals (Sweden)

    Yohannes Nigatie

    2017-09-01

    Full Text Available Nowadays, kidney failure is a problem of many peoples in the world. We know that the main function of kidney is maintaining the chemical quality of blood particularly removing urea through urine. But when they malfunction, the pathologic state known as uremia results in a condition in which the urea is retained in the body. Failure of the kidney results in building up of harmful wastes and excess fluids in the body. Kidney diseases (failures can be due to infections, high blood pressure (hypertension, diabetes, and/or extensive use of medication. The best form of treatment is the implantation of a healthy kidney from a donor. However, this is often not possible due to the limited availability of human organs. Chronic kidney failure requires the treatment using a tube dialyzer called dialysis. Blood is taken out of the body and passes through a special membrane that removes waste and extra fluids. The clean blood is then returned to the body. The process is controlled by a dialysis machine (tube dialyzer which is equipped with a blood pump and monitoring systems to ensure safety. So this article investigates the real application of mathematics (diffusion in medical science, and it also contains the mathematical formulation and interpretation of tube dialyzer in relation to diffusion.

  14. Shining new light on braided rivers: capturing grain-to-reach scale morphodynamics with terrestrial laser scanning

    Science.gov (United States)

    Brasington, J.; Williams, R. D.; Vericat, D.; Hicks, M.; Goodsell, B.

    2011-12-01

    The last decade has witnessed a technological revolution in the acquisition of geospatial data. These developments have profound implications for the practice of river science, creating a step-change in the dimensionality, resolution and precision of measurement of fluvial forms and processes. The pace of change has been remarkable; typical datasets of channel geometry have grown from cross-sections containing a few hundred survey observations, to airborne lidar surveys incorporating millions of points. With wide-area terrestrial laser scans comprising tens of billions observations now set to emerge, our data perspectives have been expanded by seven orders of magnitude. Such rapid modernization brings with it new challenges and necessitates the development of novel data management strategies, original algorithms to process dense 3d data, higher dimensional spatial metrics and innovative simulation methods to make optimal use of this rich vein of information. In this paper we describe a field-to-product methodology which aims to address these challenges and has been used to generate an unparalleled dataset capturing the morphological evolution of a labile gravel-bed braided river through a continuous sequence of floods between Oct 2009 and May 2010. These data were generated using a data-fusion approach that combines close-range terrestrial laser scanning with bathymetric data derived from non-metric aerial photography. Surveys were acquired over a 2.5 x 0.7 km reach of the Rees River; a piedmont braided system draining a highland catchment of Southern Alps of NZ. During a 10 month field campaign through the summer flood season, this study reach was resurveyed systematically after each competent flood event. Multi-scale DEMs were derived that capture the spatial distribution of facies and morphological changes at high precision. Results indicate that over 80% of the reach was subject to significant erosion or deposition, with a complex pattern of response to the

  15. Antimocrobial Polymer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Huang, Zhi-Heng (Walnut Creek, CA); Wright, Stacy C. (Columbus, GA)

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  16. Reliability of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Kadokami, E. [Mitsubishi Heavy Industries Ltd., Hyogo-ku (Japan)

    1997-02-01

    The author presents results on studies made of the reliability of steam generator (SG) tubing. The basis for this work is that in Japan the issue of defects in SG tubing is addressed by the approach that any detected defect should be repaired, either by plugging the tube or sleeving it. However, this leaves open the issue that there is a detection limit in practice, and what is the effect of nondetectable cracks on the performance of tubing. These studies were commissioned to look at the safety issues involved in degraded SG tubing. The program has looked at a number of different issues. First was an assessment of the penetration and opening behavior of tube flaws due to internal pressure in the tubing. They have studied: penetration behavior of the tube flaws; primary water leakage from through-wall flaws; opening behavior of through-wall flaws. In addition they have looked at the question of the reliability of tubing with flaws during normal plant operation. Also there have been studies done on the consequences of tube rupture accidents on the integrity of neighboring tubes.

  17. Flexural Behavior of GFRP Tubes Filled with Magnetically Driven Concrete.

    Science.gov (United States)

    Xie, Fang; Chen, Ju; Dong, Xinlong; Feng, Bing

    2018-01-08

    Experimental investigation of GFRP (glass fiber reinforced polymer) tubes that were filled with magnetically driven concrete was carried out to study the flexural behavior of specimens under bending. Specimens having different cross section and lengths were tested. The test specimens were fabricated by filling magnetically driven concrete into the GFRP tubes and the concrete was vibrated using magnetic force. Specimens vibrated using vibrating tube were also tested for comparison. In addition, specimens having steel reinforcing bars and GFRP bars were both tested to study the effect of reinforcing bars on the magnetically driven concrete. The load-displacement curves, load-strain curves, failure mode, and ultimate strengths of test specimens were obtained. Design methods for the flexural stiffness of test specimens were also discussed in this study.

  18. Flexural Behavior of GFRP Tubes Filled with Magnetically Driven Concrete

    Directory of Open Access Journals (Sweden)

    Fang Xie

    2018-01-01

    Full Text Available Experimental investigation of GFRP (glass fiber reinforced polymer tubes that were filled with magnetically driven concrete was carried out to study the flexural behavior of specimens under bending. Specimens having different cross section and lengths were tested. The test specimens were fabricated by filling magnetically driven concrete into the GFRP tubes and the concrete was vibrated using magnetic force. Specimens vibrated using vibrating tube were also tested for comparison. In addition, specimens having steel reinforcing bars and GFRP bars were both tested to study the effect of reinforcing bars on the magnetically driven concrete. The load-displacement curves, load-strain curves, failure mode, and ultimate strengths of test specimens were obtained. Design methods for the flexural stiffness of test specimens were also discussed in this study.

  19. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  20. Lightweight, Low-CTE Tubes Made From Biaxially Oriented LCPs

    Science.gov (United States)

    Rubin, Leslie; Federico, Frank; Formato, Richard; Larouco, John; Slager, William

    2004-01-01

    Tubes made from biaxially oriented liquid-crystal polymers (LCPs) have been developed for use as penetrations on cryogenic tanks. ( Penetrations in this context denotes feed lines, vent lines, and sensor tubes, all of which contribute to the undesired conduction of heat into the tanks.) In comparison with corresponding prior cryogenic-tank penetrations made from stainless steels and nickel alloys, the LCP penetrations offer advantages of less weight and less thermal conduction. An additional major advantage of LCP components is that one can tailor their coefficients of thermal expansion (CTEs). The estimated cost of continuous production of LCP tubes of typical sizes is about $1.27/ft ($4.17/m) [based on 1998 prices]. LCP tubes that are compatible with liquid oxygen and that feature tailored biaxial molecular orientation and quasi-isotropic properties (including quasi-isotropic CTE) have been fabricated by a combination of proprietary and patented techniques that involve the use of counterrotating dies (CRDs). Tailoring of the angle of molecular orientation is what makes it possible to tailor the CTE over a wide range to match the CTEs of adjacent penetrations of other tank components; this, in turn, makes it possible to minimize differential-thermal expansion stresses that arise during thermal cycling. The fabrication of biaxially oriented LCP tubes by use of CRDs is not new in itself. The novelty of the present development lies in tailoring the orientations and thus the CTEs and other mechanical properties of the LCPs for the intended cryogenic applications and in modifications of the CRDs for this purpose. The LCP tubes and the 304-stainless-steel tubes that the LCP tubes were intended to supplant were tested with respect to burst strength, permeability, thermal conductivity, and CTE.

  1. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

    This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show the link between experiments and theory. The intention is not to present a compilation of the currently available literature on the subject. Very few reference citations have thus been made. Each chapter has essentially the same structure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 30D-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1-12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing directly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in t...

  2. Conducting Polymers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Conducting Polymers - From a Laboratory Curiosity to the Market Place. S Ramakrishnan. Volume 16 Issue 12 December 2011 pp 1254-1265. Fulltext. Click here to view fulltext PDF. Permanent link:

  3. Polymer Microneedles

    NARCIS (Netherlands)

    Yeshurun, Yehoshua; Hefetz, Meir; Berenschot, Johan W.; de Boer, Meint J.; Altpeter, Dominique; Boom, Garrit; Boom, G.

    2003-01-01

    A method for producing microneedles. The method including disposing a first layer of a radiation sensitive polymer on to a working surface and selectively irradiating the first layer such that the first layer has at least one irradiated region and at least one non-irradiated region. The method also

  4. Multiscale approach to equilibrating model polymer melts

    DEFF Research Database (Denmark)

    Svaneborg, Carsten; Ali Karimi-Varzaneh, Hossein; Hojdis, Nils

    2016-01-01

    to be computationally effective at each scale. Density fluctuations in the melt structure above the tube scale are minimized through a Monte Carlo simulated annealing of a lattice polymer model. Subsequently the melt structure below the tube scale is equilibrated via the Rouse dynamics of a force-capped Kremer...... of 15.000 monomers. To validate the equilibration process we study the time evolution of bulk, collective, and single-chain observables at the monomeric, mesoscopic, and macroscopic length scales. Extension of the present method to longer, branched, or polydisperse chains, and/or larger system sizes...

  5. Determination of Adsorption Capacity and Kinetics of Amidoxime-Based Uranium Adsorbent Braided Material in Unfiltered Seawater Using a Flume Exposure System

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Park, Jiyeon [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Bonheyo, George T. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Jeters, Robert T. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Schlafer, Nicholas J. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Wood, Jordana R. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.

    2015-08-31

    PNNL has developed a recirculating flume system for exposing braided adsorbent material to natural seawater under realistic temperature and flow-rate exposure conditions. The flumes are constructed of transparent acrylic material; they allow external light to pass into the flumes and permit photosynthetic growth of naturally present marine organisms (biofouling). Because the system consists of two flumes, replicate experiments can be conducted in which one of the flumes can be manipulated relative to the other. For example, one flume can be darkened to eliminate light exposure by placing a black tarp over the flume such that dark/light experiments can be conducted. Alternatively, two different braided adsorbents can be exposed simultaneously with no potential cross contamination issues. This report describes the first use of the PNNL flume system to study the impact of biofouling on adsorbent capacity. Experiments were conducted with the ORNL AI8 braided adsorbent material in light-exposed and darkened flumes for a 42-day exposure experiment. The major objective of this effort is to develop a system for the exposure of braided adsorbent material to unfiltered seawater, and to demonstrate the system by evaluating the performance of adsorption material when it is exposed to natural marine biofouling as it would be when the technology is used in the marine environment. Exposures of amidoxime-based polymeric braid adsorbents prepared by Oak Ridge Natural Laboratory (ORNL) were exposed to ambient seawater at 20°C in a flume system. Adsorption kinetics and adsorption capacity were assessed using time series determinations of uranium adsorption and one-site ligand saturation modeling. Biofouling in sunlight surface seawater has the potential to significantly add substantial biogenic mass to adsorption material when it is exposed for periods greater than 21 days. The observed biomass increase in the light flume was approximately 80% of the adsorbent mass after 42 days

  6. Steam generator tube integrity program

    Energy Technology Data Exchange (ETDEWEB)

    Dierks, D.R.; Shack, W.J. [Argonne National Laboratory, IL (United States); Muscara, J.

    1996-03-01

    A new research program on steam generator tubing degradation is being sponsored by the U.S. Nuclear Regulatory Commission (NRC) at Argonne National Laboratory. This program is intended to support a performance-based steam generator tube integrity rule. Critical areas addressed by the program include evaluation of the processes used for the in-service inspection of steam generator tubes and recommendations for improving the reliability and accuracy of inspections; validation and improvement of correlations for evaluating integrity and leakage of degraded steam generator tubes, and validation and improvement of correlations and models for predicting degradation in steam generator tubes as aging occurs. The studies will focus on mill-annealed Alloy 600 tubing, however, tests will also be performed on replacement materials such as thermally-treated Alloy 600 or 690. An overview of the technical work planned for the program is given.

  7. Diffusion in a Curved Tube

    OpenAIRE

    Ogawa, Naohisa

    2011-01-01

    The diffusion of particles in confining walls forming a tube is discussed. Such a transport phenomenon is observed in biological cells and porous media. We consider the case in which the tube is winding with curvature and torsion, and the thickness of the tube is sufficiently small compared with its curvature radius. We discuss how geomerical quantities appear in a quasi-one-dimensional diffusion equation.

  8. Alternate tube plugging criteria for steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Cueto-Felgueroso, C.; Aparicio, C.B. [Tecnatom, S.A., Madrid (Spain)

    1997-02-01

    The tubing of the Steam Generators constitutes more than half of the reactor coolant pressure boundary. Specific requirements governing the maintenance of steam generator tubes integrity are set in Plant Technical Specifications and in Section XI of the ASME Boiler and Pressure Vessel Code. The operating experience of Steam Generator tubes of PWR plants has shown the existence of some types of degradatory processes. Every one of these has an specific cause and affects one or more zones of the tubes. In the case of Spanish Power Plants, and depending on the particular Plant considered, they should be mentioned the Primary Water Stress Corrosion Cracking (PWSCC) at the roll transition zone (RTZ), the Outside Diameter Stress Corrosion Cracking (ODSCC) at the Tube Support Plate (TSP) intersections and the fretting with the Anti-Vibration Bars (AVBs) or with the Support Plates in the preheater zone. The In-Service Inspections by Eddy Currents constitutes the standard method for assuring the SG tubes integrity and they permit the monitoring of the defects during the service life of the plant. When the degradation reaches a determined limit, called the plugging limit, the SG tube must be either repaired or retired from service by plugging. Customarily, the plugging limit is related to the depth of the defect. Such depth is typically 40% of the wall thickness of the tube and is applicable to any type of defect in the tube. In its origin, that limit was established for tubes thinned by wastage, which was the predominant degradation in the seventies. The application of this criterion for axial crack-like defects, as, for instance, those due to PWSCC in the roll transition zone, has lead to an excessive and unnecessary number of tubes being plugged. This has lead to the development of defect specific plugging criteria. Examples of the application of such criteria are discussed in the article.

  9. YouTube and 'psychiatry'.

    Science.gov (United States)

    Gordon, Robert; Miller, John; Collins, Noel

    2015-12-01

    YouTube is a video-sharing website that is increasingly used to share and disseminate health-related information, particularly among younger people. There are reports that social media sites, such as YouTube, are being used to communicate an anti-psychiatry message but this has never been confirmed in any published analysis of YouTube clip content. This descriptive study revealed that the representation of 'psychiatry' during summer 2012 was predominantly negative. A subsequent smaller re-analysis suggests that the negative portrayal of 'psychiatry' on YouTube is a stable phenomenon. The significance of this and how it could be addressed are discussed.

  10. Bacterial Biofilms in Jones Tubes.

    Science.gov (United States)

    Ahn, Eric S; Hauck, Matthew J; Kirk Harris, Jonathan; Robertson, Charles E; Dailey, Roger A

    To investigate the presence and microbiology of bacterial biofilms on Jones tubes (JTs) by direct visualization with scanning electron microscopy and polymerase chain reaction (PCR) of representative JTs, and to correlate these findings with inflammation and/or infection related to the JT. In this study, prospective case series were performed. JTs were recovered from consecutive patients presenting to clinic for routine cleaning or recurrent irritation/infection. Four tubes were processed for scanning electron microscopy alone to visualize evidence of biofilms. Two tubes underwent PCR alone for bacterial quantification. One tube was divided in half and sent for scanning electron microscopy and PCR. Symptoms related to the JTs were recorded at the time of recovery. Seven tubes were obtained. Five underwent SEM, and 3 out of 5 showed evidence of biofilms (60%). Two of the 3 biofilms demonstrated cocci and the third revealed rods. Three tubes underwent PCR. The predominant bacteria identified were Pseudomonadales (39%), Pseudomonas (16%), and Staphylococcus (14%). Three of the 7 patients (43%) reported irritation and discharge at presentation. Two symptomatic patients, whose tubes were imaged only, revealed biofilms. The third symptomatic patient's tube underwent PCR only, showing predominantly Staphylococcus (56%) and Haemophilus (36%) species. Two of the 4 asymptomatic patients also showed biofilms. All symptomatic patients improved rapidly after tube exchange and steroid antibiotic drops. Bacterial biofilms were variably present on JTs, and did not always correlate with patients' symptoms. Nevertheless, routine JT cleaning is recommended to treat and possibly prevent inflammation caused by biofilms.

  11. Learning from YouTube [Video Book

    Science.gov (United States)

    Juhasz, Alexandra

    2011-01-01

    YouTube is a mess. YouTube is for amateurs. YouTube dissolves the real. YouTube is host to inconceivable combos. YouTube is best for corporate-made community. YouTube is badly baked. These are a few of the things Media Studies professor Alexandra Juhasz (and her class) learned about YouTube when she set out to investigate what actually happens…

  12. Phthalocyanine polymers

    Science.gov (United States)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    A method of forming 4,4',4'',4''' -tetraamino phthalocyanines involves reducing 4,4',4'',4''' -tetranitro phthalocyanines, polymerizing the metal tetraamino phthalocyanines with a tetracarboxylic dianhydride (preferably aromatic) or copolymerizing with a tetracarboxylic dianhydride and a diamine (preferably also aromatic) to produce amic acids which are then dehydrocyclized to imides. Thermally and oxidatively stable polymers result which form tough, flexible films, varnishes, adhesives, and fibers.

  13. Polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Naik, Sanjeev

    2017-08-22

    The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

  14. Behavioral risk assessment for infectious diseases (BRAID): Self-report instrument to assess injection and noninjection risk behaviors in substance users.

    Science.gov (United States)

    Dunn, Kelly E; Barrett, Frederick S; Herrmann, Evan S; Plebani, Jennifer G; Sigmon, Stacey C; Johnson, Matthew W

    2016-11-01

    Infectious diseases such as Human Immunodeficiency Virus and Hepatitis C are a significant problem among substance abusers. Current risk behavior measures [e.g., HIV Risk Taking Behaviour Scale (HRBS) and Risk Assessment Battery (RAB)] were developed for injection drug users and do not include newly identified risks or noninjection drug use behaviors. This study developed and provided initial, internal validation of the Behavioral Risk Assessment for Infectious Diseases (BRAID) to assess infectious disease risk behaviors among alcohol and other drug users. A self-report measure was developed from literature regarding risk behaviors. Participants (total N=998) with alcohol/substance use disorder completed the measure in 2 phases to establish initial psychometric validity. Phase 1 (N=270) completed 65 self-report questions; factor analysis revealed a 12-item solution with 5 factors (Unprotected Sex with Risky Partners, Injection Use, Sex on Cocaine/Crack, Condom Availability, and Intranasal Drug Use). Infectious disease history was positively associated with Injection Use (Sample 1) and Unprotected Sex with Risky Partners (Sample 2) and negatively associated with Intranasal Drug Use (Samples 1 and 2). Phase 2 (N=728) added additional injection-related items and confirmed the factor structure of the existing BRAID. The BRAID is a 5-factor, 14-item self-report measure of past 6 month risk behaviors that is composed of noninjection and injection risk behaviors and was psychometrically confirmed. Though additional external (convergent/divergent) validation is needed, this report provides preliminary support for the use of the BRAID to assess infectious disease risk in substance users. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Infrared imaging of LED lighting tubes and fluorescent tubes

    Science.gov (United States)

    Siikanen, Sami; Kivi, Sini; Kauppinen, Timo; Juuti, Mikko

    2011-05-01

    The low energy efficiency of conventional light sources is mainly caused by generation of waste heat. We used infrared (IR) imaging in order to monitor the heating of both LED tube luminaires and ordinary T8 fluorescent tubes. The IR images showed clearly how the surface temperatures of the fluorescent tube ends quickly rose up to about +50...+70°C, whereas the highest surface temperatures seen on the LED tubes were only about +30...+40°C. The IR images demonstrated how the heat produced by the individual LED chips can be efficiently guided to the supporting structure in order to keep the LED emitters cool and hence maintain efficient operation. The consumed electrical power and produced illuminance were also recorded during 24 hour measurements. In order to assess the total luminous efficacy of the luminaires, separate luminous flux measurements were made in a large integrating sphere. The currently available LED tubes showed efficacies of up to 88 lm/W, whereas a standard "cool white" T8 fluorescent tube produced ca. 75 lm/W. Both lamp types gave ca. 110 - 130 lx right below the ceiling-mounted luminaire, but the LED tubes consume only 40 - 55% of the electric power compared to fluorescent tubes.

  16. Behavior of FRP-Confined Concrete-Filled Steel Tube Columns

    Directory of Open Access Journals (Sweden)

    Yiyan Lu

    2014-05-01

    Full Text Available This paper presents the results of an experimental study into the behavior of concrete-filled steel tube columns confined by fiber-reinforced polymer (FRP. Eleven columns were tested to investigate the effects of the FRP layer number, the thickness of the steel tube and concrete strength on their load capacity and axial deformation capacity. The experimental results indicated that the FRP wrap can effectively confine the concrete expansion and delay the local buckling of the steel tube. Both the load capacity and the axial deformation capacity of concrete-filled steel tube columns can be substantially enhanced with FRP confinement. A model is proposed to predict the load capacity of the FRP-confined concrete-filled steel tube columns. The predicted results are generally in good agreement with the experimental ones obtained in this study and in the literature.

  17. Preparation of robust braid-reinforced poly(vinyl chloride) ultrafiltration hollow fiber membrane with antifouling surface and application to filtration of activated sludge solution.

    Science.gov (United States)

    Zhou, Zhuang; Rajabzadeh, Saeid; Fang, Lifeng; Miyoshi, Taro; Kakihana, Yuriko; Matsuyama, Hideto

    2017-08-01

    Braid-reinforced hollow fiber membranes with high mechanical properties and considerable antifouling surface were prepared by blending poly(vinyl chloride) (PVC) with poly(vinyl chloride-co-poly(ethylene glycol) methyl ether methacrylate) (poly(VC-co-PEGMA)) copolymer via non-solvent induced phase separation (NIPS). The tensile strength of the braid-reinforced PVC hollow fiber membranes were significantly larger than those of previously reported various types of PVC hollow fiber membranes. The high interfacial bonding strength indicated the good compatibility between the coating materials and the surface of polyethylene terephthalate (PET)-braid. Owing to the surface segregation phenomena, the membrane surface PEGMA coverage increased upon increasing the poly(VC-co-PEGMA)/PVC blending ratio, resulting in higher hydrophilicities and bovine serum albumin (BSA) repulsion. To compare the fouling properties, membranes with similar PWPs were prepared by adjusting the dope solution composition to eliminate the effect of hydrodynamic conditions on the membrane fouling performance. The blend membranes surface exhibited considerable fouling resistance to the molecular adsorption from both BSA solution and activated sludge solution. In both cases, the flux recovered to almost 80% of the initial flux using only water backflush. Considering their great mechanical properties and antifouling resistance to activated sludge solution, these novel membranes show good potential for application in wastewater treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Drop tube technical tasks

    Science.gov (United States)

    Workman, G. L.

    1986-01-01

    Criteria, using fundamental thermochemical dynamics, were developed to assist a scientist using the Drop Tube Facility in designing a good experiment. The types of parameters involved in designing the experiments include the type of furnace, the type of atmosphere, and in general which materials are better behaved than others as determined by past experience in the facility. One of the major advantages of the facility lies in its ability to provide large undercoolings in the cooling curve during the drops. A beginning was to consider the effect of oxygen and other gases upon the amount of undercooling observed. The starting point of the thermochemistry was given by Ellingham and later transformed into what is known as the Richardson Chart. The effect of surface oxidations upon the nucleation phenomena can be observed in each specimen.

  19. Nasoenteric tube complications.

    Science.gov (United States)

    Prabhakaran, S; Doraiswamy, V A; Nagaraja, V; Cipolla, J; Ofurum, U; Evans, D C; Lindsey, D E; Seamon, M J; Kavuturu, S; Gerlach, A T; Jaik, N P; Eiferman, D S; Papadimos, T J; Adolph, M D; Cook, C H; Stawicki, S P A

    2012-01-01

    The use of nasoenteric tubes (NETs) is ubiquitous, and clinicians often take their placement, function, and maintenance for granted. NETs are used for gastrointestinal decompression, enteral feeding, medication administration, naso-biliary drainage, and specialized indications such as upper gastrointestinal bleeding. Morbidity associated with NETs is common, but frequently subtle, mandating high index of suspicion, clinical vigilance, and patient safety protocols. Common complications include sinusitis, sore throat and epistaxis. More serious complications include luminal perforation, pulmonary injury, aspiration, and intracranial placement. Frequent monitoring and continual re-review of the indications for continued use of any NET is prudent, including consideration of changing goals of care. This manuscript reviews NET-related complications and associated topics.

  20. Piezoelectric Rotary Tube Motor

    Science.gov (United States)

    Fisher, Charles D.; Badescu, Mircea; Braun, David F.; Culhane, Robert

    2011-01-01

    A custom rotary SQUIGGLE(Registered TradeMark) motor has been developed that sets new benchmarks for small motor size, high position resolution, and high torque without gear reduction. Its capabilities cannot be achieved with conventional electromagnetic motors. It consists of piezoelectric plates mounted on a square flexible tube. The plates are actuated via voltage waveforms 90 out of phase at the resonant frequency of the device to create rotary motion. The motors were incorporated into a two-axis postioner that was designed for fiber-fed spectroscopy for ground-based and space-based projects. The positioner enables large-scale celestial object surveys to take place in a practical amount of time.

  1. Flaming on YouTube

    NARCIS (Netherlands)

    Moor, Peter J.; Heuvelman, A.; Verleur, R.

    2010-01-01

    In this explorative study, flaming on YouTube was studied using surveys of YouTube users. Flaming is defined as displaying hostility by insulting, swearing or using otherwise offensive language. Three general conclusions were drawn. First, although many users said that they themselves do not flame,

  2. Enteral tube feeding in adults.

    Science.gov (United States)

    Scott, R; Bowling, T E

    2015-03-01

    Enteral tube feeding is usually a relatively straightforward method of nutritional support, and should be facilitated by a multiprofessional team. For short-term use (tube is indicated but if longer term feeding is required then a gastrostomy is appropriate, usually inserted endoscopically (a percutaneous endoscopic gastrostomy tube). The most common serious complication of a nasogastric tube is not identifying a misplaced tube within the lungs: there are clear recommendations from the National Patient Safety Agency as to how to check tube placement. Nasojejunal tubes are required in patients with gastroparesis. Tube blockage is common and is prevented by careful and regular flushing. Diarrhoea is the most complication of feeding and is often related to other medication. Clinicians need an algorithm for systematically dealing with such a problem. Refeeding syndrome may occur in malnourished patients and is characterised by low levels of potassium, phosphate, and/or magnesium, as well as disorders of water and salt balance. Identifying the at-risk patient with careful monitoring is crucial.

  3. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Amaurosis Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia NEI Home Contact Us A-Z Site Map NEI on Social Media Information in Spanish (Información en español) Website, ...

  4. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and other programs ... search for current job openings visit HHS USAJobs Home > NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI ...

  5. 27 CFR 40.352 - Cigarette tubes.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Cigarette tubes. 40.352... OF THE TREASURY (CONTINUED) TOBACCO MANUFACTURE OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND PROCESSED TOBACCO Manufacture of Cigarette Papers and Tubes Taxes § 40.352 Cigarette tubes. Cigarette tubes...

  6. Drug administration via nasogastric tube.

    Science.gov (United States)

    Clarke, Sonya

    2008-09-01

    In 2005, the National Patient Safety Agency (NPSA) highlighted concerns about the management of nasogastric tubes following reports of unnecessary deaths because of misplaced feeding tubes in infants, children and adults. During 2006, I investigated the management of nasogastric tubes (NGTs) in children (Clarke and Richardson 2007a, 2007b). This systematic review divided primary papers into three principal themes: enteral feeding via the NGT; confirmation of NGT position and associated incidence of tube placement error; and hydration via the NGT for acute gastroenteritis in children. Findings of the review are summarised here in relation to using the nasogastric tube to administer medication to children with the aim of informing practice and improving safety.

  7. A modular toolbox for gRNA-Cas9 genome engineering in plants based on the GoldenBraid standard.

    Science.gov (United States)

    Vazquez-Vilar, Marta; Bernabé-Orts, Joan Miquel; Fernandez-Del-Carmen, Asun; Ziarsolo, Pello; Blanca, Jose; Granell, Antonio; Orzaez, Diego

    2016-01-01

    The efficiency, versatility and multiplexing capacity of RNA-guided genome engineering using the CRISPR/Cas9 technology enables a variety of applications in plants, ranging from gene editing to the construction of transcriptional gene circuits, many of which depend on the technical ability to compose and transfer complex synthetic instructions into the plant cell. The engineering principles of standardization and modularity applied to DNA cloning are impacting plant genetic engineering, by increasing multigene assembly efficiency and by fostering the exchange of well-defined physical DNA parts with precise functional information. Here we describe the adaptation of the RNA-guided Cas9 system to GoldenBraid (GB), a modular DNA construction framework being increasingly used in Plant Synthetic Biology. In this work, the genetic elements required for CRISPRs-based editing and transcriptional regulation were adapted to GB, and a workflow for gRNAs construction was designed and optimized. New software tools specific for CRISPRs assembly were created and incorporated to the public GB resources site. The functionality and the efficiency of gRNA-Cas9 GB tools were demonstrated in Nicotiana benthamiana using transient expression assays both for gene targeted mutations and for transcriptional regulation. The availability of gRNA-Cas9 GB toolbox will facilitate the application of CRISPR/Cas9 technology to plant genome engineering.

  8. Bacterial adhesion to suture material in a contaminated wound model: Comparison of monofilament, braided, and barbed sutures.

    Science.gov (United States)

    Dhom, Jonas; Bloes, Dominik A; Peschel, Andreas; Hofmann, Ulf K

    2017-04-01

    Contaminated suture material plays an important role in the physiopathology of surgical site infections. Recently, suture material has been developed characterized by barbs projecting from a monofilament base. Claimed advantages for barbed sutures are a shortened wound closure time and reduced maximum wound tension. It has also been suggested that these sutures would be advantageous microbiologically. The aim of this study was to test the microbiological characteristics of the barbed Quill in comparison to the monofilament Ethilon II and the braided sutures Vicryl and triclosan-coated Vicryl Plus. In our study, sutures were cultivated on color-change agar with Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium, Escherichia coli, and Pseudomonas aeruginosa and the halo size was measured. In a second study arm with longer cultivation bacterial growth was followed by antibiotic treatment. Ethilon II and Quill showed good comparable results, whereas large halos were found around Vicryl. Vicryl Plus results depended on triclosan sensitivity. After longer bacterial cultivation and antibiotic treatment, halos were up to 3.6 times smaller on Quill than on Vicryl (p sutures can be recommended in aseptic surgery, but should only be used carefully in septic surgery. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:925-933, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  9. Experimental Techniques for Evaluating the Effects of Aging on Impact and High Strain Rate Properties of Triaxial Braided Composite Materials

    Science.gov (United States)

    Pereira, J. Michael; Roberts, Gary D.; Ruggeri, Charles R.; Gilat, Amos; Matrka, Thomas

    2010-01-01

    An experimental program is underway to measure the impact and high strain rate properties of triaxial braided composite materials and to quantify any degradation in properties as a result of thermal and hygroscopic aging typically encountered during service. Impact tests are being conducted on flat panels using a projectile designed to induce high rate deformation similar to that experienced in a jet engine fan case during a fan blade-out event. The tests are being conducted on as-fabricated panels and panels subjected to various numbers of aging cycles. High strain rate properties are being measured using a unique Hopkinson bar apparatus that has a larger diameter than conventional Hopkinson bars. This larger diameter is needed to measure representative material properties because of the large unit cell size of the materials examined in this work. In this paper the experimental techniques used for impact and high strain rate testing are described and some preliminary results are presented for both as-fabricated and aged composites.

  10. GoldenBraid 2.0: A Comprehensive DNA Assembly Framework for Plant Synthetic Biology1[C][W][OA

    Science.gov (United States)

    Sarrion-Perdigones, Alejandro; Vazquez-Vilar, Marta; Palací, Jorge; Castelijns, Bas; Forment, Javier; Ziarsolo, Peio; Blanca, José; Granell, Antonio; Orzaez, Diego

    2013-01-01

    Plant synthetic biology aims to apply engineering principles to plant genetic design. One strategic requirement of plant synthetic biology is the adoption of common standardized technologies that facilitate the construction of increasingly complex multigene structures at the DNA level while enabling the exchange of genetic building blocks among plant bioengineers. Here, we describe GoldenBraid 2.0 (GB2.0), a comprehensive technological framework that aims to foster the exchange of standard DNA parts for plant synthetic biology. GB2.0 relies on the use of type IIS restriction enzymes for DNA assembly and proposes a modular cloning schema with positional notation that resembles the grammar of natural languages. Apart from providing an optimized cloning strategy that generates fully exchangeable genetic elements for multigene engineering, the GB2.0 toolkit offers an ever-growing open collection of DNA parts, including a group of functionally tested, premade genetic modules to build frequently used modules like constitutive and inducible expression cassettes, endogenous gene silencing and protein-protein interaction tools, etc. Use of the GB2.0 framework is facilitated by a number of Web resources that include a publicly available database, tutorials, and a software package that provides in silico simulations and laboratory protocols for GB2.0 part domestication and multigene engineering. In short, GB2.0 provides a framework to exchange both information and physical DNA elements among bioengineers to help implement plant synthetic biology projects. PMID:23669743

  11. Simulating the Heterogeneity in Braided Channel Belt Deposits: Part 1. A Geometric-Based Methodology and Code

    Energy Technology Data Exchange (ETDEWEB)

    Ramanathan, Ramya; Guin, Arijit; Ritzi, Robert W.; Dominic, David F.; Freedman, Vicky L.; Scheibe, Timothy D.; Lunt, Ian A.

    2010-04-29

    A geometric-based simulation methodology was developed and incorporated into a computer code to model the hierarchical stratal architecture, and the corresponding spatial distribution of permeability, in braided channel belt deposits. The code creates digital models of these deposits as a three-dimensional cubic lattice, which can be used directly in numerical aquifer or reservoir models for fluid flow. The digital models have stratal units defined from the km scale to the cm scale. These synthetic deposits are intended to be used as high-resolution base cases in various areas of computational research on multiscale flow and transport processes, including the testing of upscaling theories. The input parameters are primarily univariate statistics. These include the mean and variance for characteristic lengths of sedimentary unit types at each hierarchical level, and the mean and variance of log-permeability for unit types defined at only the lowest level (smallest scale) of the hierarchy. The code has been written for both serial and parallel execution. The methodology is described in Part 1 of this series. In Part 2, models generated by the code are presented and evaluated.

  12. Eddy current signal comparison for tube identification

    Science.gov (United States)

    Glass, S. W.; Vojvodic, R.

    2015-03-01

    Inspection of nuclear power plant steam generator tubes is required to justify continued safe plant operation. The steam generators consist of thousands of tubes with nominal diameters of 15 to 22mm, approximately 1mm wall thickness, and 20 to 30m in length. The tubes are inspected by passing an eddy current probe through the tubes from tube end to tube end. It is critical to know exactly which tube identification (row and column) is associated with each tube's data. This is controlled by a precision manipulator that provides the tube ID to the eddy current system. Historically there have been some instances where the manipulator incorrectly reported the tube ID. This can have serious consequences including lack of inspection of a tube, or if a pluggable indication is detected, the tube is likely to be mis-plugged thereby risking a primary to secondary leak.

  13. Water-storage-tube systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hemker, P.

    1981-12-24

    Passive solar collection/storage/distribution systems were surveyed, designed, fabricated, and mechanically and thermally tested. The types studied were clear and opaque fiberglass tubes, metal tubes with plastic liners, and thermosyphoning tubes. (MHR)

  14. Fingerprinting Molecular Relaxation in Deformed Polymers

    Science.gov (United States)

    Wang, Zhe; Lam, Christopher N.; Chen, Wei-Ren; Wang, Weiyu; Liu, Jianning; Liu, Yun; Porcar, Lionel; Stanley, Christopher B.; Zhao, Zhichen; Hong, Kunlun; Wang, Yangyang

    2017-07-01

    The flow and deformation of macromolecules is ubiquitous in nature and industry, and an understanding of this phenomenon at both macroscopic and microscopic length scales is of fundamental and practical importance. Here, we present the formulation of a general mathematical framework, which could be used to extract, from scattering experiments, the molecular relaxation of deformed polymers. By combining and modestly extending several key conceptual ingredients in the literature, we show how the anisotropic single-chain structure factor can be decomposed by spherical harmonics and experimentally reconstructed from its cross sections on the scattering planes. The resulting wave-number-dependent expansion coefficients constitute a characteristic fingerprint of the macromolecular deformation, permitting detailed examinations of polymer dynamics at the microscopic level. We apply this approach to survey a long-standing problem in polymer physics regarding the molecular relaxation in entangled polymers after a large step deformation. The classical tube theory of Doi and Edwards predicts a fast chain retraction process immediately after the deformation, followed by a slow orientation relaxation through the reptation mechanism. This chain retraction hypothesis, which is the keystone of the tube theory for macromolecular flow and deformation, is critically examined by analyzing the fine features of the two-dimensional anisotropic spectra from small-angle neutron scattering by entangled polystyrenes. We show that the unique scattering patterns associated with the chain retraction mechanism are not experimentally observed. This result calls for a fundamental revision of the current theoretical picture for nonlinear rheological behavior of entangled polymeric liquids.

  15. Fingerprinting Molecular Relaxation in Deformed Polymers

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    2017-07-01

    Full Text Available The flow and deformation of macromolecules is ubiquitous in nature and industry, and an understanding of this phenomenon at both macroscopic and microscopic length scales is of fundamental and practical importance. Here, we present the formulation of a general mathematical framework, which could be used to extract, from scattering experiments, the molecular relaxation of deformed polymers. By combining and modestly extending several key conceptual ingredients in the literature, we show how the anisotropic single-chain structure factor can be decomposed by spherical harmonics and experimentally reconstructed from its cross sections on the scattering planes. The resulting wave-number-dependent expansion coefficients constitute a characteristic fingerprint of the macromolecular deformation, permitting detailed examinations of polymer dynamics at the microscopic level. We apply this approach to survey a long-standing problem in polymer physics regarding the molecular relaxation in entangled polymers after a large step deformation. The classical tube theory of Doi and Edwards predicts a fast chain retraction process immediately after the deformation, followed by a slow orientation relaxation through the reptation mechanism. This chain retraction hypothesis, which is the keystone of the tube theory for macromolecular flow and deformation, is critically examined by analyzing the fine features of the two-dimensional anisotropic spectra from small-angle neutron scattering by entangled polystyrenes. We show that the unique scattering patterns associated with the chain retraction mechanism are not experimentally observed. This result calls for a fundamental revision of the current theoretical picture for nonlinear rheological behavior of entangled polymeric liquids.

  16. Inventory of Long-Term Braiding Activity at a Regional Scale as a Tool for Detecting Alterations to a Rivers' Hydromorphological State: A Case Study for Romania's South-Eastern Subcarpathians

    Science.gov (United States)

    Ioana-Toroimac, Gabriela

    2016-07-01

    The inventory of long-term braiding activity is a useful tool for detecting alterations in a rivers' hydromorphological state and for a river's management in the context of the Water Framework Directive on integrated river basin management for Europe. Our study focuses on braided sectors of rivers in South-Eastern Subcarpathians (Romania). The inventory evaluates types of alterations based on the spatial analysis of fluvial morphology indicators (i.e., length of the river sector forming a braided pattern; width of the braided active channel), and vegetation cover (i.e., length of banks covered by forest and shrubs; area of in-stream patches of shrubs) accumulated over the last century. Furthermore, we performed a regional scale hierarchical cluster analysis to estimate the degree of alteration when compared to an historical baseline. In South-Eastern Subcarpathians, the studied rivers experienced a decrease of braiding activity revealed by the shortening and narrowing of their braided sectors, expansion of riparian forests, and the diminishment of vegetated islands' areas. We separated three types of river clusters, corresponding to low (cluster 1), moderate (cluster 2), and high (cluster 3) degree of alteration. Moreover, the clusters demonstrate the evolutionary path of the braided pattern alterations until the functioning of another channel pattern. The inventory is relevant for differing types and levels of alterations. Additionally, this tool may serve as a first step toward the restoration of altered sectors by identifying rivers in cluster 1 as potential candidates of present-day reference sites for altered rivers with similar natural conditions as in cluster 3.

  17. Tunable Optical Polymer Systems

    National Research Council Canada - National Science Library

    Jenekhe, S. A; Bard, Allen J; Chen, S. H; Hammond, P. T; Rothberg, L. J

    2004-01-01

    .... The synthesis and properties of new electrochromic polymers are described. Electrochromic devices incorporating conjugated polymers have been fabricated and found to be durable past 100,000 cycles...

  18. Flux tubes at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cea, Paolo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cuteri, Francesca; Papa, Alessandro [Dipartimento di Fisica, Università della Calabria & INFN-Cosenza,Ponte Bucci, cubo 31C, I-87036 Rende (Cosenza) (Italy)

    2016-06-07

    The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm ≃1.6/√σ and the temperature is increased towards and above the deconfinement temperature T{sub c}, the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube “evaporation” above T{sub c} has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.

  19. Method of making straight fuel cell tubes

    Science.gov (United States)

    Borglum, Brian P.

    2001-01-01

    A method and an apparatus for making straight fuel cell tubes are disclosed. Extruded tubes comprising powders of fuel cell material and a solvent are dried by rotating the extruded tubes. The rotation process provides uniform circumferential drying which results in uniform linear shrinkage of the tubes. The resultant dried tubes are very straight, thereby eliminating subsequent straightening steps required with conventional processes. The method is particularly useful for forming inner air electrode tubes of solid oxide fuel cells.

  20. From Commodity Polymers to Functional Polymers

    OpenAIRE

    Tao Xiang,; Ling-Ren Wang; Lang Ma; Zhi-Yuan Han; Rui Wang; Chong Cheng; Yi Xia; Hui Qin; Chang-Sheng Zhao

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outs...

  1. PEG tubes: dealing with complications.

    Science.gov (United States)

    Malhi, Hardip; Thompson, Rosie

    A percutaneous endoscopic gastronomy tube can be used to deliver nutrition, hydration and medicines directly into the patient's stomach. Patients will require a tube if they are unable to swallow safely, putting them at risk of aspiration of food, drink and medicines into their lungs. It is vital that nurses are aware of the complications that may arise when caring for a patient with a PEG tube. It is equally important that nurses know how to deal with these complications or from where tc seek advice. This article provides a quick troubleshooting guide to help nurses deal with complications that can arise with PEG feeding.

  2. Glass Tube Design for CRT(Cathode Ray Tube)

    OpenAIRE

    Junko, ITOH; Keizo, KISHIDA; Koji, NAKAMURA; Masayuki, Miyazaki; Shigeo, OHSUGI; Sumio, YOSHIOKA; Department of Precision Science & Technology, Osaka University; Mitsubishi Elec.Corp.

    2000-01-01

    Stress and deformation of cathode ray tubes(CRTs)under atmospheric pressure and implosion protection band tightening were analyzed using a finite element method(FEM). The stress and deformation of the tubes were measured experimentally by using strain gages and three-dimensional position measuring techniques. The experimental results showed close agreements with those of the simulation. The location of the highest tensile stress and the effects of tightening of the implosion protection bands ...

  3. Entangled Polymer-Nanocomposites: Dynamics and phase stability

    Science.gov (United States)

    Mangal, Rahul; Srivastava, Samanvaya; Archer, Lynden

    2015-03-01

    Polymer nanocomposites (PNCs) prepared by incorporating nanoparticles (NPs) in polymer hosts, have been reported to exhibit unusual mechanical, dynamical, and glassy features when the particle size approaches the random coil dimensions of the host polymer, even at low NP content. By taking advantage of favorable enthalpic interactions between particle-tethered and high-molecular weight host polymer molecules, we show by means of small-angle X-ray scattering that it is possible to create model PNCs in which spherical NPs are uniformly dispersed in polymeric hosts. Using these materials as model systems for studying polymer dynamics, we find that even at low concentrations, NPs profoundly alter a host polymer's dynamics on all timescales. On short timescales, NPs slow-down fast segmental motions and lowers the glass transition temperature of the host. On intermediate timescales where entanglement and tube dynamics are typically observed in entangled melts, NPs hasten the onset of these effects, leading to an early transition to reptation behavior. On long timescales, NPs lead to an earlier than expected onset of tube escape. This latter behavior appears correlated with previous reports of viscosity reductions in entangled PNCs, but in reality would only be experimentally observable in systems where nanoparticles do not also slow-down segmental scale motions of their polymer host.

  4. Flexible intramuscular micro tube electrode combining electrical and chemical interface.

    Science.gov (United States)

    Tian, Hong-Chang; Liu, Jing-Quan; Du, Jing-Cheng; Kang, Xiao-Yang; Zhang, Chuan; Yang, Bin; Chen, Xiang; Yang, Chun-Sheng

    2014-01-01

    With the rapidly developed micromachining technology, various kinds of sophisticated microelectrodes integrated with micro fluidic channels are design and fabricated for not only electrophysiological recording and stimulation, but also chemical drug delivery. As many efforts have been devoted to develop rigid microprobes for neural research of brain, few researchers concentrate on fabrication of flexible microelectrodes for intramuscular electrophysiology and chemical interfacing. Since crude wire electrodes still prevail in functional electrical stimulation (FES) and electromyography (EMG) recording of muscle, here we introduce a flexible micro tube electrode combining electrical and chemical pathway. The proposed micro tube electrode is manufactured based on polymer capillary, which provide circumferential electrode site contacting with electro-active tissue and is easy to manufactured with low cost.

  5. Mechanical strength of boron nitride nanotube-polymer interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoming; Ke, Changhong, E-mail: xqwang@uga.edu, E-mail: cke@binghamton.edu [Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, New York 13902 (United States); Zhang, Liuyang; Wang, Xianqiao, E-mail: xqwang@uga.edu, E-mail: cke@binghamton.edu [College of Engineering, University of Georgia, Athens, Georgia 30602 (United States); Park, Cheol [NASA Langley Research Center, Hampton, Virginia 23681 (United States); Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Fay, Catharine C. [NASA Langley Research Center, Hampton, Virginia 23681 (United States)

    2015-12-21

    We investigate the mechanical strength of boron nitride nanotube (BNNT) polymer interfaces by using in situ electron microscopy nanomechanical single-tube pull-out techniques. The nanomechanical measurements show that the shear strengths of BNNT-epoxy and BNNT-poly(methyl methacrylate) interfaces reach 323 and 219 MPa, respectively. Molecular dynamics simulations reveal that the superior load transfer capacity of BNNT-polymer interfaces is ascribed to both the strong van der Waals interactions and Coulomb interactions on BNNT-polymer interfaces. The findings of the extraordinary mechanical strength of BNNT-polymer interfaces suggest that BNNTs are excellent reinforcing nanofiller materials for light-weight and high-strength polymer nanocomposites.

  6. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Grants and Funding Extramural Research Division of Extramural Science Programs Division of Extramural Activities Extramural Contacts NEI ... Amaurosis Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded ...

  7. Epidemiology of neural tube defects

    National Research Council Canada - National Science Library

    Seidahmed, Mohammed Z; Abdelbasit, Omar B; Shaheed, Meeralebbae M; Alhussein, Khalid A; Miqdad, Abeer M; Khalil, Mohamed I; Al-Enazy, Naif M; Salih, Mustafa A

    2014-01-01

    To find the prevalence of neural tube defects (NTDs), and compare the findings with local and international data, and highlight the important role of folic acid supplementation and flour fortification with folic acid in preventing NTDs...

  8. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Intern Program Diversity In Vision Research & Ophthalmology (DIVRO) Student Training Programs To search for current job openings visit HHS USAJobs Home > NEI YouTube Videos > ...

  9. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... questions Clinical Studies Publications Catalog Photos and Images Spanish Language Information Grants and Funding Extramural Research Division ... Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video ...

  10. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... and Aging Program African American Program Training and Jobs Fellowships NEI Summer Intern Program Diversity In Vision ... DIVRO) Student Training Programs To search for current job openings visit HHS USAJobs Home > NEI YouTube Videos > ...

  11. Examination of gavage tube placement in children.

    Science.gov (United States)

    Ellett, M L; Beckstrand, J

    1999-01-01

    A primary issue in ensuring safe and effective enteral feeding by tube is achieving and maintaining correct tube position. This study was conducted to determine the prevalence of tube placement errors, risk factors associated with these errors, and accuracy of commonly used bedside placement-screening methods. In this descriptive study, 39 hospitalized children having one or more types of enteral tubes were studied prospectively. Tube placement was assessed across time, using three common placement-screening methods compared to radiographs. Tube placement error occurred in 43.5% of tubes at least once during the observation period. Children who were comatose or semicomatose, were inactive, had swallowing problems, or had Argyle tubes were more likely to have tube placement errors. Findings suggest that radiographs to document tube placement may be needed, at least on initial enteral tube insertion.

  12. From Commodity Polymers to Functional Polymers

    Science.gov (United States)

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications. PMID:24710333

  13. Dermatology on YouTube.

    Science.gov (United States)

    Boyers, Lindsay N; Quest, Tyler; Karimkhani, Chante; Connett, Jessica; Dellavalle, Robert P

    2014-06-15

    YouTube, reaches upwards of six billion users on a monthly basis and is a unique source of information distribution and communication. Although the influence of YouTube on personal health decision-making is well established, this study assessed the type of content and viewership on a broad scope of dermatology related content on YouTube. Select terms (i.e. dermatology, sun protection, skin cancer, skin cancer awareness, and skin conditions) were searched on YouTube. Overall, the results included 100 videos with over 47 million viewers. Advocacy was the most prevalent content type at 24% of the total search results. These 100 videos were "shared" a total of 101,173 times and have driven 6,325 subscriptions to distinct YouTube user pages. Of the total videos, 35% were uploaded by or featured an MD/DO/PhD in dermatology or other specialty/field, 2% FNP/PA, 1% RN, and 62% other. As one of the most trafficked global sites on the Internet, YouTube is a valuable resource for dermatologists, physicians in other specialties, and the general public to share their dermatology-related content and gain subscribers. However, challenges of accessing and determining evidence-based data remain an issue.

  14. Characterization Of Biaxial Strain Of Poly(L-Lactide) Tubes

    DEFF Research Database (Denmark)

    Løvdal, Alexandra Liv Vest; Andreasen, Jens Wenzel; Mikkelsen, Lars Pilgaard

    2016-01-01

    Poly(L-lactide) (PLLA) in its L-form has promising mechanical properties. Being a semi-crystalline polymer, it can be subjected to strain-induced crystallization at temperatures above Tg and can thereby become oriented. Following a simultaneous (SIM) biaxial strain process or a sequential (SEQ......) biaxial strain process, the mechanical properties of biaxial strained tubes can be further improved. This study investigated these properties in relation to their morphology and crystal orientation. Both processes yield the same mechanical strength and modulus, yet exhibit different crystal orientation...

  15. Tea-bag-like polymer nanoreactors filled with gold nanoparticles.

    Science.gov (United States)

    Mitschang, Fabian; Schmalz, Holger; Agarwal, Seema; Greiner, Andreas

    2014-05-05

    Gold-containing polymer nanotubes, which showed both catalytic activity and resistance to leaching, were prepared by the "tubes by fiber templates" (TUFT) process. For this purpose, electrospun polymer nonwovens with incorporated poly(L-lactide)-stabilized gold nanoparticles were coated with poly(p-xylylene) by the chemical vapor deposition process, and then the inner fiber templates were removed. The resulting polymer tubes carried encapsulated gold nanoparticles which were shown to be immobilized and featured pronounced catalytic activity towards the hydrolytic oxidation of dimethylphenylsilane and the alcoholysis of dimethylphenylsilane with n-butanol. The macroscopic nonwovens could be used as tea-bag-like catalyst systems and showed excellent reusability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  17. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  18. Comparison of the mechanical characteristics of polymerized caprolactam and monofilament nylon loops constructed in parallel strands or as braided ropes versus cranial cruciate ligaments of cattle.

    Science.gov (United States)

    Niehaus, Andrew J; Anderson, David E; Johnson, Jed K; Lannutti, John J

    2013-03-01

    To compare the mechanical characteristics of polymerized caprolactam and monofilament nylon loops with those of the cranial cruciate ligament (CCL) in cattle. 6 femorotibial joints harvested from 3 cows and suture constructs made from No. 8 polymerized caprolactam, 80-lb test monofilament nylon fishing line, and 450-lb test monofilament nylon fishing line. Joints were cleared of soft tissue structures except the CCL, connected to a load frame, and loaded to failure while measuring force and elongation. Synthetic constructs tested in a similar manner included single-stranded and 3-stranded No. 8 polymerized caprolactam, 3- and 6-stranded 80-lb test monofilament nylon fishing line, and 3- and 6-stranded 450-lb test monofilament nylon fishing line. The CCL ruptured at a mean ± SD force of 4,541 ± 1,417 N with an elongation of 2.0 ± 0.3 cm. The tensile strength of 3-stranded 450-lb test monofilament nylon fishing line was similar to that of the CCL, rupturing at loads of 5,310 ± 369 N (braided strands) and 6,260 ± 239 N (parallel strands). Elongation was greater for braided constructs. The 3-stranded cords of 450-lb test monofilament nylon fishing line most closely approximated the strength of the CCL. Marked increases in elongation occur when large-sized materials are constructed in braided configurations, and this elongation would likely not provide stability in CCL-deficient stifle joints. Additional studies are needed to determine whether any of these materials are suitable CCL replacements in cattle.

  19. ATLAS muon drift tube production in Seattle

    CERN Document Server

    Zhao, T; Kuykendall, W; Davisson, R

    2004-01-01

    The drift tube production facility that we developed for producing precision drift tubes of the ATLAS forward muon system in our laboratory is described in this paper. The results of quality assurance for approximately 30,000 tube produced are given. Our experience shows that this production facility is very efficient and the quality of produced drift tubes is very high. (2 refs).

  20. 27 CFR 41.35 - Cigarette tubes.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Cigarette tubes. 41.35... OF THE TREASURY (CONTINUED) TOBACCO IMPORTATION OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND PROCESSED TOBACCO Taxes Tax Rates § 41.35 Cigarette tubes. Cigarette tubes are taxed at the following rates...

  1. 21 CFR 872.6570 - Impression tube.

    Science.gov (United States)

    2010-04-01

    ... DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6570 Impression tube. (a) Identification. An impression tube is a device consisting of a hollow copper tube intended to take an impression of a single tooth... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Impression tube. 872.6570 Section 872.6570 Food...

  2. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  3. Physics of magnetic flux tubes

    CERN Document Server

    Ryutova, Margarita

    2015-01-01

    This book is the first account of the physics of magnetic flux tubes from their fundamental properties to collective phenomena in an ensembles of flux tubes. The physics of magnetic flux tubes is absolutely vital for understanding fundamental physical processes in the solar atmosphere shaped and governed by magnetic fields. High-resolution and high cadence observations from recent space and  ground-based instruments taken simultaneously at different heights and temperatures not only show the ubiquity of filamentary structure formation but also allow to study how various events are interconnected by system of magnetic flux tubes. The book covers both theory and observations. Theoretical models presented in analytical and phenomenological forms are tailored for practical applications. These are welded with state-of-the-art observations from early decisive ones to the most recent data that open a new phase-space for exploring the Sun and sun-like stars. Concept of magnetic flux tubes is central to various magn...

  4. DNA as a Model for Probing Polymer Entanglements: Circular Polymers and Non-Classical Dynamics

    Directory of Open Access Journals (Sweden)

    Kathryn Regan

    2016-09-01

    Full Text Available Double-stranded DNA offers a robust platform for investigating fundamental questions regarding the dynamics of entangled polymer solutions. The exceptional monodispersity and multiple naturally occurring topologies of DNA, as well as a wide range of tunable lengths and concentrations that encompass the entanglement regime, enable direct testing of molecular-level entanglement theories and corresponding scaling laws. DNA is also amenable to a wide range of techniques from passive to nonlinear measurements and from single-molecule to bulk macroscopic experiments. Over the past two decades, researchers have developed methods to directly visualize and manipulate single entangled DNA molecules in steady-state and stressed conditions using fluorescence microscopy, particle tracking and optical tweezers. Developments in microfluidics, microrheology and bulk rheology have also enabled characterization of the viscoelastic response of entangled DNA from molecular levels to macroscopic scales and over timescales that span from linear to nonlinear regimes. Experiments using DNA have uniquely elucidated the debated entanglement properties of circular polymers and blends of linear and circular polymers. Experiments have also revealed important lengthscale and timescale dependent entanglement dynamics not predicted by classical tube models, both validating and refuting new proposed extensions and alternatives to tube theory and motivating further theoretical work to describe the rich dynamics exhibited in entangled polymer systems.

  5. Simulating the Heterogeneity in Braided Channel Belt Deposits: 2. Examples of Results and Comparison to Natural Deposits

    Energy Technology Data Exchange (ETDEWEB)

    Guin, Arijit; Ramanathan, Ramya; Ritzi, Robert W.; Dominic, David F.; Lunt, Ian A.; Scheibe, Timothy D.; Freedman, Vicky L.

    2010-04-29

    In Part 1 of this series we presented a methodology and a code for modeling the hierarchical sedimentary architecture in braided channel belt deposits. Here, in Part 2, the code was used to create a digital model of this architecture, and the corresponding spatial distribution of permeability. The simulated architecture was compared to the real stratal architecture observed in an abandoned channel belt of the Sagavanirktok River, Alaska by Lunt et al. (2004). The comparisons included assessments of similarity which were both qualitative and quantitative. From the qualitative comparisons we conclude that a synthetic deposit created by the code has unit types, at each level, with a geometry which is generally consistent with the geometry of unit types observed in the field. The digital unit types would generally be recognized as representing their counterparts in nature, including cross stratasets, lobate and scroll bar deposits, channel fills, etc. Furthermore, the synthetic deposit has a hierarchical spatial relationship among these units which represents how the unit types are observed in field exposures and in geophysical images. In quantitative comparisons the proportions and the length, width, and height of unit types at different scales, across all levels of the stratal hierarchy compare well between the digital and the natural deposits. A number of important attributes of the channel belt model were shown to be influenced by more than one level within the hierarchy of stratal architecture. First, the high-permeability open-framework gravels percolated at all levels and thus formed preferential flow pathways. Open framework gravels are indeed known to form preferential flow pathways in natural channel belt deposits. The nature of a percolating cluster changed across different levels of the hierarchy of stratal architecture. As a result of this geologic structure, the percolation occurs at proportions of open-framework gravels below the theoretical percolation

  6. Tubing and cable cutting tool

    Science.gov (United States)

    Mcsmith, D. D.; Richardson, J. I. (Inventor)

    1984-01-01

    A hand held hydraulic cutting tool was developed which is particularly useful in deactivating ejection seats in military aircraft rescue operations. The tool consists primarily of a hydraulic system composed of a fluid reservoir, a pumping piston, and an actuator piston. Mechanical cutting jaws are attached to the actuator piston rod. The hydraulic system is controlled by a pump handle. As the pump handle is operated the actuator piston rod is forced outward and thus the cutting jaws are forced together. The frame of the device is a flexible metal tubing which permits easy positioning of the tool cutting jaws in remote and normally inaccessible locations. Bifurcated cutting edges ensure removal of a section of the tubing or cable to thereby reduce the possibility of accidental reactivation of the tubing or cable being severed.

  7. On hydraulics of capillary tubes

    Directory of Open Access Journals (Sweden)

    N.G. Aloyan

    2016-03-01

    Full Text Available The article considers the laws of motion of water in the capillary tubes, taken as a model for flowing well, on the analogical net count device. For capillary tube the lower limit value of flow rate is empirically determined above which the total hydraulic resistance of the capillary is practically constant. The specificity of the phenomenon is that the regime of motion, by a Reynolds number, for a given flow rate still remains laminar. This circumstance can perplex the specialists, so the author invites them to the scientific debate on the subject of study. Obviously, to identify the resulting puzzle it is necessary to conduct a series of experiments using capillaries of different lengths and diameters and with different values of overpressure. The article states that in tubes with very small diameter the preliminary magnitude of capillary rise of water in the presence of flow plays no role and can be neglected.

  8. Drift tubes of Linac 2

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    With the advent of the 800 MeV PS Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows Linac 2 drift-tubes, suspended on stems coming from the top, in contrast to Linac 1, where the drift-tubes stood on stems coming from the bottom.

  9. Design and fabrication of an IPMC-embedded tube for minimally invasive surgery applications

    Science.gov (United States)

    Liu, Jiayu; Wang, Yanjie; Zhao, Dongxu; Zhang, Chi; Chen, Hualing; Li, Dichen

    2014-03-01

    Minimally Invasive Surgery (MIS) is receiving much attention for a number of reasons, including less trauma, faster recovery and enhanced precision. The traditional robotic actuators do not have the capabilities required to fulfill the demand for new applications in MIS. Ionic Polymer-Metal Composite (IPMC), one of the most promising smart materials, has extensive desirable characteristics such as low actuation voltage, large bending deformation and high functionality. Compared with traditional actuators, IPMCs can mimic biological muscle and are highly promising for actuation in robotic surgery. In this paper, a new approach which involves molding and integrating IPMC actuators into a soft silicone tube to create an active actuating tube capable of multi-degree-of-freedom motion is presented. First, according to the structure and performance requirements of the actuating tube, the biaxial bending IPMC actuators fabricated by using solution casting method have been implemented. The silicone was cured at a suitable temperature to form a flexible tube using molds fabricated by 3D Printing technology. Then an assembly based fabrication process was used to mold or integrate biaxial bending IPMC actuators into the soft silicone material to create an active control tube. The IPMC-embedded tube can generate multi-degree-of-freedom motions by controlling each IPMC actuator. Furthermore, the basic performance of the actuators was analyzed, including the displacement and the response speed. Experimental results indicate that IPMC-embedded tubes are promising for applications in MIS.

  10. Bismuth@US-tubes as a Potential Contrast Agent for X-ray Imaging Applications

    Science.gov (United States)

    Rivera, Eladio J.; Tran, Lesa A.; Hernández-Rivera, Mayra; Yoon, Diana; Mikos, Antonios G.; Rusakova, Irene A.; Cheong, Benjamin Y.; Cabreira-Hansen, Maria da Graça; Willerson, James T.; Perin, Emerson C.; Wilson, Lon J.

    2013-01-01

    The encapsulation of bismuth as BiOCl/Bi2O3 within ultra-short (ca. 50 nm) single-walled carbon nanocapsules (US-tubes) has been achieved. The Bi@US-tubes have been characterized by high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Bi@US-tubes have been used for intracellular labeling of pig bone marrow-derived mesenchymal stem cells (MSCs) to show high X-ray contrast in computed tomography (CT) cellular imaging for the first time. The relatively high contrast is achieved with low bismuth loading (2.66% by weight) within the US-tubes and without compromising cell viability. X-ray CT imaging of Bi@US-tubes-labeled MSCs showed a nearly two-fold increase in contrast enhancement when compared to unlabeled MSCs in a 100 kV CT clinical scanner. The CT signal enhancement from the Bi@US-tubes is 500 times greater than polymer-coated Bi2S3 nanoparticles and several-fold that of any clinical iodinated contrast agent (CA) at the same concentration. Our findings suggest that the Bi@US-tubes can be used as a potential new class of X-ray CT agent for stem cell labeling and possibly in vivo tracking. PMID:24288589

  11. Conducting polymer materials

    Directory of Open Access Journals (Sweden)

    Jovanović Slobodan M.

    2003-01-01

    Full Text Available Conducting polymers represent a very interesting group of polymer materials Investigation of the synthesis, structure and properties of these materials has been the subject of considerable research efforts in the last twenty years. A short presentating of newer results obtained by investigating of the synthesis, structure and properties of two basic groups of conducting polymers: a conducting polymers the conductivity of which is the result of their molecular structure, and b conducting polymer composites (EPC, is given in this paper. The applications and future development of this group of polymer materials is also discussed.

  12. The pollen tube paradigm revisited.

    Science.gov (United States)

    Kroeger, Jens; Geitmann, Anja

    2012-12-01

    The polar growth process characterizing pollen tube elongation has attracted numerous modeling attempts over the past years. While initial models focused on recreating the correct cellular geometry, recent models are increasingly based on experimentally assessed cellular parameters such as the dynamics of signaling processes and the mechanical properties of the cell wall. Recent modeling attempts have therefore substantially gained in biological relevance and predictive power. Different modeling methods are explained and the power and limitations of individual models are compared. Focus is on several recent models that use closed feedback loops in order to generate limit cycles representing the oscillatory behavior observed in growing tubes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. YouTube and Facebook

    DEFF Research Database (Denmark)

    Robertson, Scott P.; Vatrapu, Ravi; Medina, Richard

    This paper examines the links to YouTube from the Facebook “walls” of Barack Obama, Hillary Clinton, and John McCain over two years prior to the 2008 U.S. Presidential election. User-generated linkage patterns show how participants in these politically-related social networking dialogues used...... online video to make their points. We show a strong integration of the Web 2.0 and new media technologies of social networking and online video. We argue that political discussion in social networking environments can no longer be viewed as primarily textual, and that neither Facebook nor YouTube can...

  14. Working session 3: Tubing integrity

    Energy Technology Data Exchange (ETDEWEB)

    Cueto-Felgueroso, C. [Tecnatom, S.A., San Sebastian de los Reyes, Madrid (Spain); Strosnider, J. [NRC, Washington, DC (United States)

    1997-02-01

    Twenty-three individuals representing nine countries (Belgium, Canada, the Czech Republic, France, Japan, the Slovak Republic, Spain, the UK, and the US) participated in the session on tube integrity. These individuals represented utilities, vendors, consultants and regulatory authorities. The major subjects discussed by the group included overall objectives of managing steam generator tube degradation, necessary elements of a steam generator degradation management program, the concept of degradation specific management, structural integrity evaluations, leakage evaluations, and specific degradation mechanisms. The group`s discussions on these subjects, including conclusions and recommendations, are summarized in this article.

  15. Orifice plates and venturi tubes

    CERN Document Server

    Reader-Harris, Michael

    2015-01-01

    This book gives the background to differential-pressure flow measurement and goes through the requirements explaining the reason for them. For those who want to use an orifice plate or a Venturi tube the standard ISO 5167 and its associated Technical Reports give the instructions required.  However, they rarely tell the users why they should follow certain instructions.  This book helps users of the ISO standards for orifice plates and Venturi tubes to understand the reasons why the standards are as they are, to apply them effectively, and to understand the consequences of deviations from the standards.

  16. Biocompatibility of Different Nerve Tubes

    Directory of Open Access Journals (Sweden)

    Hisham Fansa

    2009-09-01

    Full Text Available Bridging nerve gaps with suitable grafts is a major clinical problem. The autologous nerve graft is considered to be the gold standard, providing the best functional results; however, donor site morbidity is still a major disadvantage. Various attempts have been made to overcome the problems of autologous nerve grafts with artificial nerve tubes, which are “ready-to-use” in almost every situation. A wide range of materials have been used in animal models but only few have been applied to date clinically, where biocompatibility is an inevitable prerequisite. This review gives an idea about artificial nerve tubes with special focus on their biocompatibility in animals and humans.

  17. Depositional System Transition from Braided River to Tide Dominated Delta-A Case Study of the MPE3 Block in the Eastern Venezuelan Basin

    Science.gov (United States)

    Huang, Wensong; Chen, Heping; Xu, Fang; Meng, Zheng; Li, Yonghao

    2017-04-01

    The Eastern Venezuelan basin is a world-class petroliferous area, with the sedimentary environment controlled by the interaction between the Caribbean plate and the American plate. Based on interpretation of 3D seismic data, description of electrical well-logging facies and analysis of the sedimentary phenomena on the cores, we distinguished different types of sedimentary associations and clarified the evolution progress of the sedimentary system in the study area, the MPE3 Block. We put forward that depositional system in the study area changed from braided river in the early Miocene to tide dominated delta in the middle Miocene. Paralleled with sedimentary progress, the depositional hydrodynamic mechanism altered from the inertia dominated setting into the buoyancy dominated setting. During the middle Miocene, the tidal effect obviously reworked and formed tidal bars and tidal channels, both severing as the sedimentary framework. From the perspective of the tectonic movement, the study area varied from the foreland stage during the early Miocene to the compression and inverse stage during the middle Miocene. At the same time, the study area located in the southern part of the foreland basin began to extend and marine transgression occurred due to the tectonic extensional movement. We pointed out that critical factors influencing the transition from braided river to tidal dominate delta include palaeogeomorphology, sea level fluctuation, feeder system and the distance to catchment area.

  18. Pump element for a tube pump

    DEFF Research Database (Denmark)

    2011-01-01

    The invention relates to a tube pump comprising a tube and a pump element inserted in the tube, where the pump element comprises a rod element and a first and a second non-return valve member positioned a distance apart on the rod element. The valve members are oriented in the same direction...... portion acts to alternately close and open the valve members thereby generating a fluid flow through the tube. The invention further relates to a pump element comprising at least two non-return valve members connected by a rod element, and for insertion in an at least partly flexible tube in such tube...... pump as mentioned above, thereby acting to generate a fluid flow through the tube upon repeated deformation of the tube between the two valve members. The pump element may comprise a connecting part for coupling to another tube and may comprise a sealing part establishing a fluid tight connection...

  19. Effects of Polymer Parameters on Drag Reduction.

    Science.gov (United States)

    Safieddine, Abbas Mohammad

    The effects of polymer parameters on fluid drag reduction using polyethylene oxide (PEO), polyacrylamide (PAM), guar gum (GG) and hydroxyethyl cellulose (HEC) were investigated. Due to the unavailability of high molecular weight (MW) water-soluble polymers having narrow molecular weight distribution (MWD), an aqueous preparative size exclusion chromatography (SEC) system capable of fractionating over wide MW ranges was constructed. An online low shear viscometer, coupled to the SEC, measured the instantaneous intrinsic viscosity of the eluting polymer solution and, therefore, served as a MW detector since Mark-Houwink "K" and "a" values for all four polymers were known. With the aid of the viscometer, the SEC system was calibrated. The preparative nature of the chromatography system allowed the collection of large volumes of nearly monodisperse fractions (MWD daltons. Also, the preparative SEC approach allowed drag reduction (DR) experiments using well-characterized, narrowly dispersed polymer solutions under controlled tube flow conditions. Correlations of drag reduction performance with primary polymer parameters (i.e., concentration, intrinsic viscosity ((eta)), volume fraction (c(eta)), number of chain links (N), and combinations thereof) were used to test the validity of several theoretical DR models. Walsh's energy model, as well as the Deborah argument, did not completely account for drag reduction behavior under all experimental conditions. Within each of the flexible or rigid polymer groups, the extensional viscosity model was successful in correlating c(eta) N with DR under all turbulent conditions. However, it failed to account for the differences in chemical structure between the two polymer groups. However, when the cellulosic repeat unit was used instead of the carbon-carbon bond as the chain link for the rigid polymers (GG and HEC), all DR versus c (eta) N curves under all turbulent conditions collapsed into a single function. This has been predicted

  20. Fingerprinting polymer microarrays.

    Science.gov (United States)

    Tourniaire, Guilhem; Diaz-Mochon, Juan J; Bradley, Mark

    2009-08-01

    The incubation of "polymer microarrays" with labelled proteins and carbohydrates demonstrated polymer selective binding, giving an approach to cellular fingerprinting and offering a possible alternative to current arraying platforms for partitioning and analysis of complex cellular components.

  1. Mechanical Properties of Polymers.

    Science.gov (United States)

    Aklonis, J. J.

    1981-01-01

    Mechanical properties (stress-strain relationships) of polymers are reviewed, taking into account both time and temperature factors. Topics include modulus-temperature behavior of polymers, time dependence, time-temperature correspondence, and mechanical models. (JN)

  2. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    polymerized in a controlled manner with carrier monomers of historically proven biocompatible polymers. The carrier polymers, the loading of ribavirin as well as the size of the polymer were varied systematically with the aid of an automated synthesis platform. These polymers were tested in a cellular assay...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein......The field of drug delivery is in essence an exercise in engineered pharmacokinetics. Methods of doing so have been developed through the introduction of a vehicle carrying the drug, either by encapsulation or covalent attachment. The emergence of polymer therapeutics in anticancer therapy has...

  3. Anion exchange polymer electrolytes

    Science.gov (United States)

    Kim, Yu Seung; Kim, Dae Sik

    2015-06-02

    Anion exchange polymer electrolytes that include guanidinium functionalized polymers may be used as membranes and binders for electrocatalysts in preparation of anodes for electrochemical cells such as solid alkaline fuel cells.

  4. , , :An Eternal Golden Braid

    Indian Academy of Sciences (India)

    2015-11-07

    Nov 7, 2015 ... Quantum Gravity as a Quantum Field Theory? (The Limitations of Imitations). String Theory - Infancy and Early Successes. (How to sensibly scatter gravitons). String Theory - Addressing the Puzzles of Black. Holes (How to account for BH entropy). Quantum Gravity as a Quantum Field Theory! (Onwards to a ...

  5. Rheology modification with ring polymers

    Science.gov (United States)

    Vlassopoulos, Dimitris

    It is now established that experimental unconcatenated ring polymers can be purified effectively by means of fractionation at the critical condition. For molecular weights well above the entanglement threshold, purified rings relax stress via power-law (with an exponent of about -0.4), sharply departing from their linear counterparts. Experimental results are in harmony with modeling predictions and simulations. Here, we present results from recent interdisciplinary efforts and discuss two challenges: (i) the nonlinear shear rheology of purified ring melts is also very different from that of unlinked chains. Whereas the latter exhibit features that can be explained, to a first approach, in the framework in the tube model, the former behave akin to unentangled chains with finite extensibility and exhibit much small deformation at steady state. (ii) blends of rings and linear polymers exhibit unique features in different regimes: The addition of minute amounts of linear chains drastically affects ring dynamics. This relates to ring purity and the ability of unlinked linear chains to thread rings. With the help of simulations, it is possible to rationalize the observed surprisingly slow viscoelastic relaxation, which is attributed to ring-linear and ring-ring penetrations. On the other hand, adding small amounts of rings to linear polymers of different molecular weights influences their linear and nonlinear rheology in an unprecedented way. The blend viscosity exceeds that of the slower component (linear) in this non-interacting mixture, and its dependencies on composition and molecular weight ratio are examined, whereas the role of molecular architecture is also addressed. Consequently, closing the ends of a linear chain can serve as a powerful means for molecular manipulation of its rheology. This presentation reflects collaborative efforts with S. Costanzo, Z-C. Yan, R. Pasquino, M. Kaliva, S. Kamble, Y. Jeong, P. Lutz, J. Allgaier, T. Chang, D. Talikis, V

  6. Thermal inhomogeneities in vortex tubes

    Science.gov (United States)

    Lemesh, N. I.; Senchuk, L. A.

    An experimental study of the effect of the temperature of the inlet gas on the temperature difference between the hot and cold streams discharged from a Ranque-Hilsch vortex tube is described. The experimental results are presented in graphical form. It is that the temperature difference increases with the temperature of the entering gas.

  7. Working session 1: Tubing degradation

    Energy Technology Data Exchange (ETDEWEB)

    Kharshafdjian, G. [Atomic Energy of Canada, Mississauga, Ontario (Canada); Turluer, G. [IPSN, Fontenay-aux-Roses (France)

    1997-02-01

    A general introductory overview of the purpose of the group and the general subject area of SG tubing degradation was given by the facilitator. The purpose of the session was described as to {open_quotes}develop conclusions and proposals on regulatory and technical needs required to deal with the issues of SG tubing degradation.{close_quotes} Types, locations and characteristics of tubing degradation in steam generators were briefly reviewed. The well-known synergistic effects of materials, environment, and stress and strain/strain rate, subsequently referred to by the acronym {open_quotes}MESS{close_quotes} by some of the group members, were noted. The element of time (i.e., evolution of these variables with time) was emphasized. It was also suggested that the group might want to consider the related topics of inspection capabilities, operational variables, degradation remedies, and validity of test data, and some background information in these areas was provided. The presentation given by Peter Millet during the Plenary Session was reviewed; Specifically, the chemical aspects and the degradation from the secondary side of the steam generator were noted. The main issues discussed during the October 1995 EPRI meeting on secondary side corrosion were reported, and a listing of the potential SG tube degradations was provided and discussed.

  8. Kundt's Tube Experiment Using Smartphones

    Science.gov (United States)

    Parolin, Sara Orsola; Pezzi, Giovanni

    2015-01-01

    This article deals with a modern version of Kundt's tube experiment. Using economic instruments and a couple of smartphones, it is possible to "see" nodes and antinodes of standing acoustic waves in a column of vibrating air and to measure the speed of sound.

  9. Vitamins and neural tube defects

    OpenAIRE

    Harris, Rodney

    1988-01-01

    The use of vitamin supplements by women around the time of conception was examined and compared in those having babies with neural tube defects, those with still births or some other type of malformation, and in women who had normal babies.

  10. OurTube / David Talbot

    Index Scriptorium Estoniae

    Talbot, David

    2009-01-01

    USA California Ülikooli töötajate Abram Stern'i ja Michael Dale'i poolt 2005. a. algatatud USA kongressis peetud kõnede videoremiksidest ja nende poolt loodud veebisaidist Metavid.org. Ka YouTube keskkonnast ja wikipedia katsetustest muuta oma keskkond multimeedialisemaks

  11. Fin-tube solar collectors

    Science.gov (United States)

    1980-01-01

    Report presents test procedures and results of thermal-performance evaluation of seven commercial fin tube (liquid) solar collector-absorber plates. Tests were conducted indoors at Marshall Space Flight Center Solar simulator. Results are graphically shown along with supporting test data and summary, indicating efficiency as function of collector inlet temperature.

  12. Tube Suction Test for Evaluating

    Science.gov (United States)

    2012-06-01

    In a comprehensive laboratory study, different tests namely, unconfined compressive strength (UCS) at the end of freeze-thaw/wet-dry (F-T/W-D) cycles, resilient modulus (Mr) at the end of F-T/W-D cycles, vacuum saturation, tube suction, and moisture ...

  13. Building your own shock tube

    NARCIS (Netherlands)

    J. Naber (Jorick)

    2005-01-01

    textabstractThis report treats the development of a shock tube solver for the simulation of flows described by the one-dimensional Euler equations. A well-known one-dimensional flow problem is the initial Riemann problem, which treats the development of a flow due to two initially separated

  14. Welding the CNGS decay tube

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    3.6 km of welds were required for the 1 km long CERN Neutrinos to Gran Sasso (CNGS) decay tube, in which particles produced in the collision with a proton and a graphite target will decay into muons and muon neutrinos. Four highly skilled welders performed this delicate task.

  15. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement.

  16. POLYMER CONCRETE CREEP

    OpenAIRE

    Yu. М. Borisov; I. S. Surovtsev; Yu. B. Potapov

    2012-01-01

    Problem statement. It is well known that creep is the tendency of a solid material to move slowly or deform permanently under the influence of stresses. The aim of the paper is to study the process of creep in polymer concretes. Results and conclusions. It is shown that creep in polymer concrete occurs according to the same pattern as in many other polymer composites with the elastic core. Equations which indirectly es-tablish the relation between complete deformations of polymer concrete, in...

  17. Modeling semiflexible polymer networks

    OpenAIRE

    Broedersz, Chase P.; MacKintosh, Fred C.

    2014-01-01

    Here, we provide an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have been motivated by their importance in biology. Indeed, crosslinked networks of semiflexible polymers form a major structural component of tissue and living cells. Reconstituted networks o...

  18. Biopolymers Versus Synthetic Polymers

    OpenAIRE

    Florentina Adriana Cziple; António J. Velez Marques

    2008-01-01

    This paper present an overview of important synthetic and natural polymers with emphasis on polymer structure, the chemistry of polymer formation. an introduction to polymer characterization. The biodegradation process can take place aerobically and anaerobically with or without the presence of light. These factors allow for biodegradation even in landfill conditions which are normally inconducive to any degradation. The sheeting used to make these packages differs...

  19. Schizophrenia on YouTube.

    Science.gov (United States)

    Nour, Matthew M; Nour, Murraih H; Tsatalou, Olga-Maria; Barrera, Alvaro

    2017-01-01

    YouTube ( www.youtube.com ) is the most popular video-sharing Web site on the Internet and is used by medical students as a source of information regarding mental health conditions, including schizophrenia. The accuracy and educational utility of schizophrenia presentations on YouTube are unknown. The purpose of this study was to analyze the accuracy of depictions of psychosis in the context of a diagnosis of schizophrenia (referred to in this article as "acute schizophrenia") on YouTube and to assess the utility of these videos as educational tools for teaching medical students to recognize the clinical features of acute schizophrenia. YouTube was searched for videos purporting to show acute schizophrenia. Eligible videos were independently rated by two consultant psychiatrists on two separate occasions 22 days apart for diagnostic accuracy, psychopathology, and educational utility. Videos (N=4,200) were assessed against predefined inclusion and exclusion criteria. The majority were not eligible for further analysis, mostly because they did not claim to show a patient with schizophrenia (74%) or contained duplicated content (11%). Of 35 videos that met the eligibility and adequacy criteria, only 12 accurately depicted acute schizophrenia. Accurate videos were characterized by persecutory delusions (83%), inappropriate affect (75%), and negative symptoms (83%). Despite the fact that 83% of accurate videos were deemed to have good educational utility compared with 15% of inaccurate videos, accurate and inaccurate videos had similar view counts (290,048 versus 186,124). Schizophrenia presentations on YouTube offer a distorted picture of the condition.

  20. A case of a 'lost' nasogastric tube.

    Science.gov (United States)

    Sankar, V; Shakeel, M; Keh, S; Ah-See, K W

    2012-12-01

    To present the case of a 'lost' nasogastric tube and to highlight the importance of imaging and/or chest X-ray after nasogastric tube insertion, especially in unreliable patients. A 50-year-old man, undergoing radiotherapy treatment for squamous cell carcinoma of the tongue base, was admitted for pain control and nasogastric tube feeding. This patient required multiple nasogastric tubes over a two-week period. The patient repeatedly denied pulling the nasogastric tube out and we were unable to establish the exact mode of nasogastric tube removal. On one such occasion another tube was inserted and a check X-ray showed two feeding tubes; the latest one was lying in the left main bronchus and the old nasogastric tube was observed in the oesophagus, with its upper end jutting above the hypopharynx. It was apparent that the patient had somehow cut the tube and swallowed it. This case not only illustrates the importance of flexible nasendoscopy and/or chest X-ray for checking the position of the nasogastric tube, but also highlights that some patients are not tolerant of nasogastric tubes. The use of nasogastric tubes should be avoided in these patients to prevent any self-inflicted injury.

  1. Thermosetting Phthalocyanine Polymers

    Science.gov (United States)

    Fohlen, G.; Parker, J.; Achar, B.

    1985-01-01

    Group of phthalocyanine polymers resist thermal degradation. Polymers expected semiconducting. Principal applications probably in molded or laminated parts that have to withstand high temperatures. Polymers made from either of two classes of monomer: Bisphthalonitriles with imide linkages or Bisphthalonitriles with ester-imide linkages.

  2. Modeling semiflexible polymer networks

    NARCIS (Netherlands)

    Broedersz, C.P.; MacKintosh, F.C.

    2014-01-01

    This is an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have

  3. Aerogel / Polymer Composite Materials

    Science.gov (United States)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2017-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  4. Small bore ceramic laser tube inspection light table

    Science.gov (United States)

    Updike, Earl O.

    1990-01-01

    Apparatus for inspecting small bore ceramic laser tubes, which includes a support base with one or more support rollers. A fluorescent light tube is inserted within the laser tube and the laser tube is supported by the support rollers so that a gap is maintained between the laser tube and the fluorescent tube to enable rotation of the laser tube. In operation, the ceramic tube is illuminated from the inside by the fluorescent tube to facilitate visual inspection. Centering the tube around the axial light of the fluorescent tube provides information about straightness and wall thickness of the laser tube itself.

  5. The accessory fallopian tube: A rare anomaly

    Directory of Open Access Journals (Sweden)

    Kusum R Gandhi

    2012-01-01

    Full Text Available This paper presents a rare anatomical variation in the form of accessory fallopian tube on right side. The duplication of fallopian tube was observed in a 34-year-old female during routine undergraduate dissection in our department. Fallopian tube is the part of uterus that carries the ovum from the ovary to the uterus. Accessory fallopian tube is the congenital anomaly attached to the ampullary part of main tube. This accessory tube is common site of pyosalpinx, hydrosalpinx, cystic swelling and torsion. The ovum released by the ovary may also be captured by the blind accessory tube leading to infertility or ectopic pregnancy. Hence, all patients of infertility or pelvic inflammatory disease should be screened to rule out the presence of accessory fallopian tube and if encountered should be removed.

  6. Investigation of polymer ball lightning objects in atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Bychkov, V.L. [Inst. for High Temperature, Moscow (Russian Federation); Klimov, A.I. [Moscow Radiotechnical Inst. (Russian Federation)

    1995-12-31

    The generation and evolution of power intensive Ball Lightning Objects (BLO) or polymer plasmoids in air were investigated. The experimental arrangement consisted of electric discharge gun (EDG), capacitor storage with energy stored up to 5.6 kJ, electron trigger, limiting inductance 100-1000 {mu}H. EDG represented cone discharge tube 5 cm length, with cone opening 30-120{degrees}. Inner wall was covered by candle wax. Diameter of tube outlet was 10-30 mm. Time of pulse was about 30 ms, its amplitude was not higher than 60 A.

  7. Fire-safe polymers and polymer composites

    Science.gov (United States)

    Zhang, Huiqing

    The intrinsic relationships between polymer structure, composition and fire behavior have been explored to develop new fire-safe polymeric materials. Different experimental techniques, especially three milligram-scale methods---pyrolysis-combustion flow calorimetry (PCFC), simultaneous thermal analysis (STA) and pyrolysis GC/MS---have been combined to fully characterize the thermal decomposition and flammability of polymers and polymer composites. Thermal stability, mass loss rate, char yield and properties of decomposition volatiles were found to be the most important parameters in determining polymer flammability. Most polymers decompose by either an unzipping or a random chain scission mechanism with an endothermic decomposition of 100--900 J/g. Aromatic or heteroaromatic rings, conjugated double or triple bonds and heteroatoms such as halogens, N, O, S, P and Si are the basic structural units for fire-resistant polymers. The flammability of polymers can also be successfully estimated by combining pyrolysis GC/MS results or chemical structures with TGA results. The thermal decomposition and flammability of two groups of inherently fire-resistant polymers---poly(hydroxyamide) (PHA) and its derivatives, and bisphenol C (BPC II) polyarylates---have been systematically studied. PHA and most of its derivatives have extremely low heat release rates and very high char yields upon combustion. PHA and its halogen derivatives can completely cyclize into quasi-polybenzoxazole (PBO) structures at low temperatures. However, the methoxy and phosphate derivatives show a very different behavior during decomposition and combustion. Molecular modeling shows that the formation of an enol intermediate is the rate-determining step in the thermal cyclization of PHA. BPC II-polyarylate is another extremely flame-resistant polymer. It can be used as an efficient flame-retardant agent in copolymers and blends. From PCFC results, the total heat of combustion of these copolymers or blends

  8. A Rouse-tube model of dynamic rubber viscoelasticity

    Energy Technology Data Exchange (ETDEWEB)

    Vandoolaeghe, W L; Terentjev, E M [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2007-12-07

    The dynamic-mechanical response of a polymer network has been calculated using a stress-based Rouse model formalism. In contrast to the previous work, this improved formulation incorporates appropriate boundary conditions and provides a smooth crossover from the classical equilibrium result of rubber elasticity to the short time-scale relaxation. We develop a consistent implementation of the classical tube model, which is merged with the Rouse dynamics to take into account the entanglement effects. In a polymer network, crosslinks prevent the global reptation and constraint release. Entanglements thus acquire a different topological meaning and have a much stronger effect on the resulting mechanical response. We construct a dynamic stress tensor for a polymer network, which naturally covers the whole frequency/time range. Using this stress tensor, we first examine the equilibrium response to small shear and uniaxial deformations, and then investigate the linear dynamic response of a network for all the cases where the stress-tensor computations are analytically tractable.

  9. Macromolecular Diffusion in Dynamic Polymer Nanocomposite

    Science.gov (United States)

    Lin, Chia-Chun; Cargnello, Matteo; Clarke, Nigel; Winey, Karen; Composto, Russell

    2015-03-01

    We consider diffusion of tracer polymers in the presence of mobile nanoparticles in polymer nanocomposites (PNCs). These nanoparticles are mobile on the time scale of polymer diffusion and have dimensions less than the entanglement mesh size (i.e., tube diameter). The PNC consists of titanium dioxide nanorods (NR, diameter=4.5nm; length=30.1nm) grafted with phenyl groups uniformly dispersed in a polystyrene (P=650kg/mol; tube diameter=8nm) matrix up to 10 volume percent. Three deuterated polystyrenes (dPS; M=800, 1800 and 3200 kg/mol) are chosen because their diffusion relative to NR allows for investigating fixed and mobile NR by simply changing M. For all M, the reduced tracer diffusivities are observed to decrease monotonically as NR loading increases. However, the reduced diffusivity of dPS (3200 kg/mol) is faster than expected compared to the fixed NR case. These findings suggest that mobile NR do not effectively slow down tracer diffusion relative to fixed particles. To test this hypothesis, dPS diffusion is investigated in a high molecular weight matrix PS (2000 kg/mol) in order to slow down NR diffusion relative to dPS (3200 kg/mol). New models are needed to incorporate these mobility dependent entanglements into a comprehensive understanding of dynamics in PNCs. Primary fundings: NSF/EPSRC Materials World Network DMR-1210379 (KIW, RJC) and EP/5065373/1 (NC). Support also by the NSF/MRSEC-DMR 11-20901, and Polymer Programs DMR 09-07493.

  10. Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

    National Research Council Canada - National Science Library

    Zhang, Xuejun, Ph.D

    1999-01-01

    Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

  11. Models for Automated Tube Performance Calculations

    Energy Technology Data Exchange (ETDEWEB)

    C. Brunkhorst

    2002-12-12

    High power radio-frequency systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance.

  12. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)

    2017-01-01

    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  13. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  14. Polymer friction Molecular Dynamics

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force....

  15. Insta-Head: An Instant Headgear Tube

    Directory of Open Access Journals (Sweden)

    Rajesh B Kuril

    2011-01-01

    Full Text Available Specialized headgear tubes are required for fabrication of appliances, such as activator-headgear and twin-block with headgear. The common problems with these tubes are that they need to be purchased beforehand and they are expensive. The present article describes the chairside fabrication of a simple, inexpensive headgear tube (insta-head without the need of any specialized armamentarium.

  16. A Novel Mediastinal Drainage Tube for Mediastinitis

    Directory of Open Access Journals (Sweden)

    Jun Ho Yhang

    2015-10-01

    Full Text Available Mediastinitis is a life-threatening disease, and effective drainage is needed to treat mediastinitis with abscess formation. We recommend an alternative drainage method using chest tube binding with a Silastic Penrose drainage tube. The use of a Silastic Penrose drainage tube may help to manage mediastinitis with abscess formation. This method facilitates effective draining and prevents tissue adhesion.

  17. Studies of Degraded Smelt Spout Opening Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, James R [ORNL; Kish, Joseph R. [Paprican; Willoughby, Adam W [ORNL; Longmire, Hu Foster [ORNL; Singbeil, Douglas [Paprican

    2007-01-01

    Co-extruded type 304L stainless steel/SA210 carbon steel tubes have been used on the floors and lower walls of many black liquor recovery boilers to address the wall thinning problem that had been an issue for boiler owners and operators. Use of these tubes greatly reduced the corrosion issue, but corrosion was still sometimes observed and cracking was discovered in some tubes, particularly those that are bent to form the openings for smelt spouts. Because cracks in the opening tubes were sometimes observed to extend a significant distance into the tube wall and because these cracks were found fairly frequently, tubes made from a number of alternate cladding materials were tried in place of the 304L clad opening tubes. This paper describes the results of examinations of spout opening tubes of the standard 304L/carbon steel and of several of the alternate materials that have been tried. In addition to the corrosion and cracking seen in the spout opening tubes, another issue associated with these tubes has been observed. Preferential corrosion of the cap welds is sometimes seen on butt welds attaching the spout opening tubes made with alternate cladding materials to the standard 304L/carbon steel co-extruded wall tubes. Some information on the observations of this corrosion is also included in this paper.

  18. Radioactive fallout and neural tube defects

    African Journals Online (AJOL)

    Nejat Akar

    2015-07-10

    Jul 10, 2015 ... Neural tube defects;. Anencephaly;. Spina bifida. Abstract Possible link between radioactivity and the occurrence of neural tube defects is a long lasting debate ... Neural tube defects, are one of the common congenital mal- formations ... ent cities of Turkey (˙Izmir/Aegean Region; Trabzon/Black Sea region ...

  19. Clinical Burden of Laparoscopic Feeding Jejunostomy Tubes.

    Science.gov (United States)

    Speer, Emily A; Chow, Simon C; Dunst, Christy M; Shada, Amber L; Halpin, Valerie; Reavis, Kevin M; Cassera, Maria; Swanström, Lee L

    2016-05-01

    Feeding jejunostomies (J tubes) provide enteral nutrition when oral and gastric routes are not options. Despite their prevalence, there is a paucity of literature regarding their efficacy and clinical burden. All laparoscopic J tubes placed over a 5-year period were retrospectively reviewed. Clinical burden was measured by number of clinical contact events (tube-related clinic visits, phone calls, ED visits) and morbidity (dislodgement, clogging, tube fracture, infection, other). Tube replacements were also recorded. One hundred fifty-one patients were included. Fifty-nine percent had associated malignancy, and 35 % were placed for nutritional prophylaxis. Mean time to J tube removal was 146 days. J tubes were expected to be temporary in >90 % but only 50 % had sufficient oral intake for removal. Tubes were removed prematurely due to patient intolerance in 8 %. Mortality was 0 %. Morbidity was 51 % and included clogging (12 %), tube fracture (16 %), dislodgement (25 %), infection (18 %) and "other" (leaking, erosion, etc.) in 17 %. The median number of adverse events per J tube was 2(0-8). Mean number of clinic phone calls was 2.5(0-22), ED visits 0.5(0-7), and clinic visits 1.4(0-13), with 82 % requiring more than one J tube-related clinic visit. Unplanned replacements occurred in 40 %. While necessary for some patients, J tubes are associated with high clinical burden.

  20. Roll-forming tubes to header plates

    Science.gov (United States)

    Kramer, K.

    1976-01-01

    Technique has been developed for attaching and sealing tubes to header plates using a unique roll-forming tool. Technique is useful for attaching small tubes which are difficult to roll into conventional grooves in header plate tube holes, and for attaching when welding, brazing, or soldering is not desirable.

  1. The Fuge Tube Diode Array Spectrophotometer

    Science.gov (United States)

    Arneson, B. T.; Long, S. R.; Stewart, K. K.; Lagowski, J. J.

    2008-01-01

    We present the details for adapting a diode array UV-vis spectrophotometer to incorporate the use of polypropylene microcentrifuge tubes--fuge tubes--as cuvettes. Optical data are presented validating that the polyethylene fuge tubes are equivalent to the standard square cross section polystyrene or glass cuvettes generally used in…

  2. Kundt's Tube: An Acoustic Gas Analyzer

    Science.gov (United States)

    Aristov, Natasha; Habekost, Gehsa; Habekost, Achim

    2011-01-01

    A Kundt tube is normally used to measure the speed of sound in gases. Therefore, from known speeds of sound, a Kundt tube can be used to identify gases and their fractions in mixtures. In these experiments, the speed of sound is determined by measuring the frequency of a standing sound wave at a fixed tube length, temperature, and pressure. This…

  3. Spring/dimple instrument tube restraint

    Science.gov (United States)

    DeMario, Edmund E.; Lawson, Charles N.

    1993-01-01

    A nuclear fuel assembly for a pressurized water nuclear reactor has a spring and dimple structure formed in a non-radioactive insert tube placed in the top of a sensor receiving instrumentation tube thimble disposed in the fuel assembly and attached at a top nozzle, a bottom nozzle, and intermediate grids. The instrumentation tube thimble is open at the top, where the sensor or its connection extends through the cooling water for coupling to a sensor signal processor. The spring and dimple insert tube is mounted within the instrumentation tube thimble and extends downwardly adjacent the top. The springs and dimples restrain the sensor and its connections against lateral displacement causing impact with the instrumentation tube thimble due to the strong axial flow of cooling water. The instrumentation tube has a stainless steel outer sleeve and a zirconium alloy inner sleeve below the insert tube adjacent the top. The insert tube is relatively non-radioactivated inconel alloy. The opposed springs and dimples are formed on diametrically opposite inner walls of the insert tube, the springs being formed as spaced axial cuts in the insert tube, with a web of the insert tube between the cuts bowed radially inwardly for forming the spring, and the dimples being formed as radially inward protrusions opposed to the springs.

  4. Advanced polymers in medicine

    CERN Document Server

    Puoci, Francesco

    2014-01-01

    The book provides an up-to-date overview of the diverse medical applications of advanced polymers. The book opens by presenting important background information on polymer chemistry and physicochemical characterization of polymers. This serves as essential scientific support for the subsequent chapters, each of which is devoted to the applications of polymers in a particular medical specialty. The coverage is broad, encompassing orthopedics, ophthalmology, tissue engineering, surgery, dentistry, oncology, drug delivery, nephrology, wound dressing and healing, and cardiology. The development of polymers that enhance the biocompatibility of blood-contacting medical devices and the incorporation of polymers within biosensors are also addressed. This book is an excellent guide to the recent advances in polymeric biomaterials and bridges the gap between the research literature and standard textbooks on the applications of polymers in medicine.

  5. Numerical and experimental study of an annular pulse tube used in the pulse tube cooler

    Science.gov (United States)

    Pang, Xiaomin; Chen, Yanyan; Wang, Xiaotao; Dai, Wei; Luo, Ercang

    2017-12-01

    Multi-stage pulse tube coolers normally use a U-type configuration. For compactness, it is attractive to build a completely co-axial multi-stage pulse tube cooler. In this way, an annular shape pulse tube is inevitable. Although there are a few reports about previous annular pulse tubes, a detailed study and comparison with a circular pulse tube is lacking. In this paper, a numeric model based on CFD software is carried out to compare the annular pulse tube and circular pulse tube used in a single stage in-line type pulse tube cooler with about 10 W of cooling power at 77 K. The length and cross sectional area of the two pulse tubes are kept the same. Simulation results show that the enthalpy flow in the annular pulse tube is lower by 1.6 W (about 11% of the enthalpy flow) compared to that in circular pulse tube. Flow and temperature distribution characteristics are also analyzed in detail. Experiments are then conducted for comparison with an in-line type pulse tube cooler. With the same acoustic power input, the pulse tube cooler with a circular pulse tube obtains 7.88 W of cooling power at 77 K, while using an annular pulse tube leads to a cooling power of 7.01 W, a decrease of 0.9 W (11.4%) on the cooling performance. The study sets the basis for building a completely co-axial two-stage pulse tube cooler.

  6. ATLS: Catheter and tube placement

    Science.gov (United States)

    Gosbee, John; Krupa, Debra T.; Pepper, L.; Orsak, Debra

    1991-01-01

    The specific objectives of this experiment are: to evaluate the rack mounted equipment and medical supplies necessary for medical procedures; to evaluate the attachments, mounting points, and inner drawer assemblies for the medical supplies; and to evaluate the procedures for performing medical scenarios. The resources available in the HMF miniracks to accomplish medical scenarios and/or procedures include: medical equipment mounted in the racks; a patch panel with places to attach tubing and catheters; self contained drawers full of critical care medical supplies; and an ALS 'backpack' for deploying supplies. The attachment lines, tubing and associated medical supplies will be deployed and used with the equipment and a patient mannequin. Data collection is provided by direct observations by the inflight experimenters, and analysis of still and video photography.

  7. AFRL Ludwieg Tube Initial Performance

    Science.gov (United States)

    2017-11-01

    controls the fill and purge process. A commercial Sylvania 18 kW resistance heater raises the inlet air temperature to 500K prior to filling the...Distribution is unlimited. 3 ms of uniform run conditions between wave passages. The exterior of the driver tube is heated with blanket resistance ...uniformity and noise characteristics, this has not been a major problem with wind tunnels using this type of valve. However, there has been no direct

  8. Preparation of three-dimensional braided carbon fiber-reinforced PEEK composites for potential load-bearing bone fixations. Part I. Mechanical properties and cytocompatibility.

    Science.gov (United States)

    Luo, Honglin; Xiong, Guangyao; Yang, Zhiwei; Raman, Sudha R; Li, Qiuping; Ma, Chunying; Li, Deying; Wang, Zheren; Wan, Yizao

    2014-01-01

    In this study, we focused on fabrication and characterization of three-dimensional carbon fiber-reinforced polyetheretherketone (C3-D/PEEK) composites for orthopedic applications. We found that pre-heating of 3-D fabrics before hot-pressing could eliminate pores in the composites prepared by 3-D co-braiding and hot-pressing techniques. The manufacturing process and the processing variables were studied and optimum parameters were obtained. Moreover, the carbon fibers were surface treated by the anodic oxidization and its effect on mechanical properties of the composites was determined. Preliminary cell studies with mouse osteoblast cells were also performed to examine the cytocompatibility of the composites. Feasibility of the C3-D/PEEK composites as load-bearing bone fixation materials was evaluated. Results suggest that the C3-D/PEEK composites show good promising as load-bearing bone fixations. © 2013 Elsevier Ltd. All rights reserved.

  9. Role of Entropic Barriers in Controlling Polymer Diffusion in Polystyrene Nanocomposites

    Science.gov (United States)

    Griffin, Philip; Tung, Wei-Shao; Meth, Jeffrey; Clarke, Nigel; Composto, Russell; Winey, Karen

    Polymer diffusion in polymer nanocomposites (PNCs) is significantly modified relative to the neat state. While it is suspected that nanoparticle-induced confinement plays a key role in the diffusion process, a detailed understanding of this process remains nonetheless elusive. We present recent studies of the temperature dependent polymer center-of-mass tracer diffusion coefficient in an athermal PNC comprising polystyrene and phenyl-capped, spherical silica NPs using elastic recoil detection. We find that the polymer tracer diffusion coefficient in the PNC relative to the bulk decreases with increasing nanoparticle concentration and is unexpectedly more strongly reduced at higher temperatures. This unusual temperature dependence of polymer diffusion in PNCs cannot be explained by the reptation model or a modified version incorporating an effective tube diameter, but instead it is the direct result of entropic free energy barriers imposed on polymer chains under confinement.

  10. Tube entrance lens focus control

    Science.gov (United States)

    Weisser, D. C.; Fifield, L. K.; Kitchen, T. F. G.; Tunningley, T. B.; Lobanov, N. R.; Muirhead, A. G.

    2013-02-01

    The entrance of the accelerator tube in a large electrostatic accelerator imposes a strong lens that dominates the beam optics. The magnification of the lens is large because of the low injection energy, the high voltage gradient of the acceleration tube and the long distance to the terminal. In the absence of the acceleration, the magnification would produce an unacceptably large beam spot at the terminal. The tyranny of the lens is especially irksome when the accelerator is required to operate at a lower terminal voltage than the one corresponding to the nominal gradient at high voltage. One way around the difficulty, used in NEC Pelletron accelerators, is to insert a series of nylon and steel rods that short together units of the acceleration structure at the terminal leaving the ones near the entrance close to the nominal gradient for optimum transmission. This operation takes time and risks the loss of insulating gas. Another alternative used in the 25URC at Oak Ridge National Laboratory, is to focus the beam at the tube entrance, substantially diluting the effect of the entrance lens. The beam then diverges and so requires an additional lens part way to the terminal. This solution is only partially effective and still necessitates use of shorting rods for low voltage operation. The fact that these elaborate strategies are used is evidence that the alternative of lowering the injection energy as the terminal voltage is lowered imposes enough problems that it is not used in practice. We have modeled a solution that controls the voltage gradient at the tube entrance using an external power supply. This not only maintains the focusing effect of the lens but provides the opportunity to tune the beam by adjusting the entrance lens. A 150 kV power supply outside the pressure vessel feeds a controllable voltage through a high voltage feed-through to the fifth electrode of the accelerator tube. Thus 150 kV on this electrode creates the nominal gradient of 30 kV per

  11. Gastroenteric tube feeding: Techniques, problems and solutions

    Science.gov (United States)

    Blumenstein, Irina; Shastri, Yogesh M; Stein, Jürgen

    2014-01-01

    Gastroenteric tube feeding plays a major role in the management of patients with poor voluntary intake, chronic neurological or mechanical dysphagia or gut dysfunction, and patients who are critically ill. However, despite the benefits and widespread use of enteral tube feeding, some patients experience complications. This review aims to discuss and compare current knowledge regarding the clinical application of enteral tube feeding, together with associated complications and special aspects. We conducted an extensive literature search on PubMed, Embase and Medline using index terms relating to enteral access, enteral feeding/nutrition, tube feeding, percutaneous endoscopic gastrostomy/jejunostomy, endoscopic nasoenteric tube, nasogastric tube, and refeeding syndrome. The literature showed common routes of enteral access to include nasoenteral tube, gastrostomy and jejunostomy, while complications fall into four major categories: mechanical, e.g., tube blockage or removal; gastrointestinal, e.g., diarrhea; infectious e.g., aspiration pneumonia, tube site infection; and metabolic, e.g., refeeding syndrome, hyperglycemia. Although the type and frequency of complications arising from tube feeding vary considerably according to the chosen access route, gastrointestinal complications are without doubt the most common. Complications associated with enteral tube feeding can be reduced by careful observance of guidelines, including those related to food composition, administration rate, portion size, food temperature and patient supervision. PMID:25024606

  12. Development boiling to sprinkled tube bundle

    Directory of Open Access Journals (Sweden)

    Kracík Petr

    2016-01-01

    Full Text Available 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.

  13. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira

    2015-09-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

  14. Estimation of aneurysm wall stresses created by treatment with a shape memory polymer foam device

    OpenAIRE

    Hwang, Wonjun; Volk, Brent L.; Akberali, Farida; Singhal, Pooja; Criscione, John C.; Maitland, Duncan J.

    2011-01-01

    In this study, compliant latex thin-walled aneurysm models are fabricated to investigate the effects of expansion of shape memory polymer foam. A simplified cylindrical model is selected for the in-vitro aneurysm, which is a simplification of a real, saccular aneurysm. The studies are performed by crimping shape memory polymer foams, originally 6 and 8 mm in diameter, and monitoring the resulting deformation when deployed into 4-mm-diameter thin-walled latex tubes. The deformations of the lat...

  15. Artificially Engineered Protein Polymers.

    Science.gov (United States)

    Yang, Yun Jung; Holmberg, Angela L; Olsen, Bradley D

    2017-06-07

    Modern polymer science increasingly requires precise control over macromolecular structure and properties for engineering advanced materials and biomedical systems. The application of biological processes to design and synthesize artificial protein polymers offers a means for furthering macromolecular tunability, enabling polymers with dispersities of ∼1.0 and monomer-level sequence control. Taking inspiration from materials evolved in nature, scientists have created modular building blocks with simplified monomer sequences that replicate the function of natural systems. The corresponding protein engineering toolbox has enabled the systematic development of complex functional polymeric materials across areas as diverse as adhesives, responsive polymers, and medical materials. This review discusses the natural proteins that have inspired the development of key building blocks for protein polymer engineering and the function of these elements in material design. The prospects and progress for scalable commercialization of protein polymers are reviewed, discussing both technology needs and opportunities.

  16. Comparison of complication rates, types, and average tube patency between jejunostomy tubes and percutaneous gastrostomy tubes in a regional home enteral nutrition support program.

    Science.gov (United States)

    Ao, Peter; Sebastianski, Meghan; Selvarajah, Vijeyakumar; Gramlich, Leah

    2015-06-01

    Percutaneous endoscopic gastrostomy (PEG) tubes are common enteral access devices for long-term enteral nutrition. Jejunostomy tubes (J-tubes) are able to provide postpyloric enteral access in patients who are not PEG tube candidates. There is a scarcity of literature comparing complication rates of J-tubes to PEG tubes. To compare and characterize J-tube and PEG tube complications requiring tube replacement. A retrospective chart review was performed on 560 patients discharged from the Northern Alberta Home Enteral Nutrition Support Program (NAHENSP) from January 2010 to December 2011. Patients were followed for 3 years from initial tube insertion or until discharge from the NAHENSP, whichever was earliest. Comparisons were made in terms of complications requiring tube replacement, tube patency to first replacement, and indications for tube replacement. A total of 64 J-tube patients were identified and compared with 65 PEG tube patients. Tube replacement rates for the J-tube group included 3.2 cases per 1000 patient days compared with 0.86 cases per 1000 patient days in the PEG group (P < .001). The mean ± SEM duration to first tube replacement for J-tube and PEG tube patients was 160 ± 26.3 days and 331 ± 53.6 days, respectively (P = .010). The most common causes for tube replacement in J-tube patients were dislodgement (35.6%) and obstruction (22.2%) compared with routine replacement (54.5%) and dislodgement (27.2%) in the PEG tube group. J-tubes are associated with higher complication rates requiring tube replacement compared with PEG tubes. The main causes of J-tube replacement are dislodgement and obstruction. © 2014 American Society for Parenteral and Enteral Nutrition.

  17. Thermally conductive polymers

    Science.gov (United States)

    Byrd, N. R.; Jenkins, R. K.; Lister, J. L. (Inventor)

    1971-01-01

    A thermally conductive polymer is provided having physical and chemical properties suited to use as a medium for potting electrical components. The polymer is prepared from hydroquinone, phenol, and formaldehyde, by conventional procedures employed for the preparation of phenol-formaldehyde resins. While the proportions of the monomers can be varied, a preferred polymer is formed from the monomers in a 1:1:2.4 molar or ratio of hydroquinone:phenol:formaldehyde.

  18. Effect of tube-support interaction on the dynamic responses of heat exchanger tubes. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

    1977-01-01

    Operating heat exchangers have experienced tube damages due to excessive flow-induced vibration. The relatively small inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the tube vibrational characteristics. In attempting a theoretical analysis, questions arise as to the effects of tube-baffle impacting on dynamic responses. Experiments were performed to determine the effects of tube-baffle impacting in vertical/horizontal tube orientation, and in air/water medium on the vibrational characteristics (resonant frequencies, mode shapes, and damping) and displacement response amplitudes of a seven-span tube model. The tube and support conditions were prototypic, and overall length approximately one-third that of a straight tube segment of the steam generator designed for the CRBR. The test results were compared with the analytical results based on the multispan beam with ''knife-edge'' supports.

  19. Multi-tube arrangement for combustor and method of making the multi-tube arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Ziminsky, Willy Steve [Simpsonville, SC

    2012-07-31

    A fuel injector tube includes a one piece, unitary, polygonal tube having an inlet end and an outlet end. The fuel injector tube further includes a fuel passage extending from the inlet end to the outlet end along a longitudinal axis of the polygonal tube, a plurality of air passages extending from the inlet end to the outlet end and surrounding the fuel passage, and a plurality of fuel holes. Each fuel hole connects an air passage with the fuel passage. The inlet end of the polygonal tube is formed into a fuel tube. A fuel injector includes a plurality of fuel injector tubes and a plate. The plurality of fuel tubes are connected to the plate adjacent the inlet ends of the plurality of fuel injector tubes.

  20. Polymer Conformation under Confinement

    Directory of Open Access Journals (Sweden)

    Stavros Bollas

    2017-02-01

    Full Text Available The conformation of polymer chains under confinement is investigated in intercalated polymer/layered silicate nanocomposites. Hydrophilic poly(ethylene oxide/sodium montmorillonite, PEO/Na+-MMT, hybrids were prepared utilizing melt intercalation with compositions where the polymer chains are mostly within the ~1 nm galleries of the inorganic material. The polymer chains are completely amorphous in all compositions even at temperatures where the bulk polymer is highly crystalline. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR is utilized to investigate the conformation of the polymer chains over a broad range of temperatures from below to much higher than the bulk polymer melting temperature. A systematic increase of the gauche conformation relatively to the trans is found with decreasing polymer content both for the C–C and the C–O bonds that exist along the PEO backbone indicating that the severe confinement and the proximity to the inorganic surfaces results in a more disordered state of the polymer.

  1. Antioxidant Stabilisation of Polymers

    Science.gov (United States)

    Shlyapnikov, Yurii A.

    1981-06-01

    Physicochemical aspects of the stabilisation of polymers are discussed. Attention is paid mainly to the aging and stabilisation of polymers under processing conditions. Topics considered are the kinetics and mechanism of the high-temperature oxidation of polymers, critical phenomena in the inhibited oxidation of polymers, the theory of synergism and antagonism among antioxidants, the reasons for differences in efficiency of antioxidants, and certain aspects of the relation between the efficiency of antioxidants and their molecular structure. A list of 132 references is included.

  2. Characterisation of polymers, 1

    CERN Document Server

    Crompton, Roy

    2008-01-01

    This essential guide to Polymer Characterisation is a complete compendium of methodologies that have evolved for the determination of the chemical composition of polymers. This 478-page book gives an up-to-date and thorough exposition of the state-of-the-art theories and availability of instrumentation needed to effect chemical and physical analysis of polymers. This is supported by approximately 1200 references. Volume 1 covers the methodology used for the determination of metals, non-metals and organic functional groups in polymers, and for the determination of the ratio in which different m

  3. Biopolymers Versus Synthetic Polymers

    Directory of Open Access Journals (Sweden)

    Florentina Adriana Cziple

    2008-10-01

    Full Text Available This paper present an overview of important synthetic and natural polymers with emphasis on polymer structure, the chemistry of polymer formation. an introduction to polymer characterization. The biodegradation process can take place aerobically and anaerobically with or without the presence of light. These factors allow for biodegradation even in landfill conditions which are normally inconducive to any degradation. The sheeting used to make these packages differs significantly from other “degradable plastics” in the market as it does not attempt to replace the current popular materials but instead enhances them by rendering them biodegradable.

  4. Routine jejunostomy tube feeding following esophagectomy

    Science.gov (United States)

    van Eden, Hanneke W. J.; Ruurda, Jelle P.; Luyer, Misha D. P.; Steenhagen, Elles; Nieuwenhuijzen, Grard A. P.; van Hillegersberg, Richard

    2017-01-01

    Background Malnutrition is an important problem following esophagectomy. A surgically placed jejunostomy secures an enteral feeding route, facilitating discharge with home-tube feeding and long-term nutritional support. However, specific complications occur, and data are lacking that support its use over other enteral feeding routes. Therefore routine jejunostomy tube feeding and discharge with home-tube feeding was evaluated, with emphasis on weight loss, length of stay and re-admissions. Methods Consecutive patients undergoing esophagectomy for cancer, with gastric tube reconstruction and jejunostomy creation, were analyzed. Two different regimens were compared. Before January 07, 2011 patients were discharged when oral intake was sufficient, without tube feeding. After that discharge with home-tube feeding was routinely performed. Logistic regression analysis corrected for confounders. Results Some 236 patients were included. The median duration of tube feeding was 35 days. Reoperation for a jejunostomy-related complication was needed in 2%. The median body mass index (BMI) remained stable during tube feeding. The BMI decreased significantly after stopping tube feeding: from 25.6 (1st–3rd quartile 23.0–28.6) kg/m2 to 24.4 (22.0–27.1) kg/m2 at 30 days later [median weight loss: 3.0 (1.0–5.3) kg; 3.9% (1.5–6.3%)]. Weight loss was not affected by the duration of tube feeding duration. Routine home-tube feeding did not affect weight loss, admission time or the readmission rate. Conclusions Weight loss following esophagectomy occurs once that tube feeding is stopped, independently from the time interval after esophagectomy. Moreover routine discharge with home-tube feeding does not reduce length of stay or readmissions. These findings question the value of routine jejunostomy placement and emphasize the need for further research. PMID:28815083

  5. Development of INCONEL 600 precision tube (1)

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Yeong Han; Jo, Bong Hyeon; Lee, Dong Hee; Kim, Wan Kyo; Jeong, Pyeong Keun; Yoon, Hwang Lo; Chio, Seok Sik [Sammi Steel Co. Ltd., Changwon (Korea, Republic of)

    1994-07-01

    Steam generator, being connected with nuclear fuel reactor is one of the most important part of nuclear power plant and consists of a large number of INCONEL 600 tubes. Approximately 160 tons of tubes are needed for a single nuclear power plant. All of INCONEL 600 steam generator tubes for domestic nuclear power plants have been imported. The aim of this research is to develop INCONEL 600 precision tubes for steam generator of nuclear power plant. If this research is conducted successfully, we can produce nuclear fuel tubes, Ni-alloy precision tubes and stainless steel precision tubes for many purposes and technology of INCONEL 600 steam generator tubes are similar to those of other tubes above mentioned. In the current study, development of preliminary manufacturing process of INCONEL 600 precision tubes for steam generator and investigation of material`s metallurgical characteristics were conducted. The main scope of this research is as follows. First, the preliminary manufacturing process design was conducted after investigations of foreign manufacturing processes and technical reports. Second, the results of investigations of material`s metallurgical characteristics through the manufacturing process were applied to the production technology of tentative INCONEL 600 precision tubes for sample. Third, preliminary process routes were established and samples of INCONEL 600 precision tube were produced by this process. As the results of this research, 14 pieces of INCONEL 600 precision tubes were produced by preliminary manufacturing process and the material`s metallurgical characteristics were investigated through the processes. But the SCC test could not be conducted due to the absence of equipment. In order to apply the results of SCC test to the manufacturing process, we need a SCC tester which can simulate SCC characteristics under high temperature and high pressurized circulating water. 95 refs., 55 figs., 20 tabs.

  6. Cases of fallopian tube prolapse

    Directory of Open Access Journals (Sweden)

    Sushil Chawla

    2015-01-01

    Full Text Available Fallopian tube prolapse post hysterectomy is rarely reported complication which can lead to doubts in the mind of young and experienced surgeons alike. This leads to patient morbidity and gets different medical treatments ranging from antibiotics to local applications of copper sulphate, without relief. The use of proper surgical technique, prevention of post operative hematoma and infection go a long way in its prevention.We hereby present two cases, which were manged successfully to relieve the patients of their agony.

  7. An Incentivized Capstone Design Team Applying the System Engineering Process

    Science.gov (United States)

    2015-01-02

    Kelvar is manufactured fiber spun from a liquid crystal polymer (LCP). A braided aramid Kevlar sleeve was used to cover the scrim bags. The type of Kevlar...3-foot Braided Carbon Fiber Tube, 2” dia. – 2 § Aluminum Hinge – 1 § 3/8” Push Button Pin – 2 § Shaft Collar – 4 § Protective Rubber Strip...plate so that it may be made of lighter composite materials. However, after consultation with the polymer and fiber department, it was determined that

  8. Comparison of primary jejunostomy tubes versus gastrojejunostomy tubes for percutaneous enteral nutrition.

    Science.gov (United States)

    Kim, Charles Y; Engstrom, Bjorn I; Horvath, Jeffrey J; Lungren, Matthew P; Suhocki, Paul V; Smith, Tony P

    2013-12-01

    To evaluate technical success and long-term outcomes of percutaneous primary jejunostomy tubes for postpyloric enteral feeding compared with percutaneous gastrojejunostomy (GJ) tubes. Over a 25-month interval, 41 consecutive patients (26 male; mean age, 55.9 y) underwent attempted fluoroscopy-guided direct percutaneous jejunostomy tube insertion. Insertions at previous jejunostomy tube sites were excluded. The comparison group consisted of all primary GJ tube insertions performed over a 12-month interval concomitant with the jejunostomy tube interval (N = 169; 105 male; mean age, 59.4 y). Procedural, radiologic, and clinical data were retrospectively reviewed. Intervention rates were expressed as events per 100 catheter-days. The technical success rate for percutaneous jejunostomy tube insertion was 96%, versus 93% for GJ tubes (P = .47). Mean fluoroscopy times were similar for jejunostomy and GJ tubes (9.8 vs 10.0 min, respectively; P value not significant). Jejunostomy tubes exhibited a lower rate of catheter dysfunction than GJ tubes, with catheter exchange rates of 0.24 versus 0.93, respectively, per 100 catheter-days (P = .045). GJ tube tip retraction into the stomach occurred in 9.5% of cases, at a rate of 0.21 per 100 catheter-days. Intervention rates related to leakage were 0.19 and 0.03 for jejunostomy and GJ tubes, respectively (P Jejunostomy and GJ tubes exhibited similar rates of catheter exchange for occlusion and replacement as a result of inadvertent removal. No major complications were encountered in either group. Percutaneous insertion of primary jejunostomy tubes demonstrated technical success and complication rates similar to those of GJ tubes. Jejunostomy tubes exhibited a lower dysfunction rate but a higher leakage rate compared with GJ tubes. Copyright © 2013 SIR. Published by Elsevier Inc. All rights reserved.

  9. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  10. Narratives From YouTube

    Directory of Open Access Journals (Sweden)

    Mikael Quennerstedt

    2013-10-01

    Full Text Available The aim of this paper is to explore what is performed in students’ and teachers’ actions in physical education practice in terms of “didactic irritations,” through an analysis of YouTube clips from 285 PE lessons from 27 different countries. Didactic irritations are occurrences that Rønholt describes as those demanding “didactic, pedagogical reflections and discussions, which in turn could lead to alternative thinking and understanding about teaching and learning.” Drawing on Barad’s ideas of performativity to challenge our habitual anthropocentric analytical gaze when looking at educational visual data, and using narrative construction, we also aim to give meaning to actions, relations, and experiences of the participants in the YouTube clips. To do this, we present juxtaposing narratives from teachers and students in terms of three “didactic irritations”: (a stories from a track, (b, stories from a game, and (c, stories from a bench. The stories re-present events-of-moving in the data offering insights into embodied experiences in PE practice, making students’ as well as teachers’ actions in PE practice understandable.

  11. [Enteral feeding tubes for critically ill patients].

    Science.gov (United States)

    Braun, J; Bein, T; Wiese, C H R; Graf, B M; Zausig, Y A

    2011-04-01

    The use of enteral feeding tubes is an important part of early enteral feeding in intensive care medicine. In other faculties with non-critically ill patients, such as (oncologic) surgery, neurology, paediatrics or even in palliative care medicine feeding tubes are used under various circumstances as a temporary or definite solution. The advantage of enteral feeding tubes is the almost physiologic administration of nutrition, liquids and medication. Enteral nutrition is thought to be associated with a reduced infection rate, increased mucosal function, improved immunologic function, reduced length of hospital stay and reduced costs. However, the insertion and use of feeding tubes is potentially dangerous and may be associated with life-threatening complications (bleeding, perforation, peritonitis, etc.). Therefore, the following article will give a summary of the different types of enteral feeding tubes and their range of application. Additionally, a critical look on indication and contraindication is given as well as how to insert an enteral feeding tube.

  12. Why do aged fluorescent tubes flicker?

    Science.gov (United States)

    Plihon, Nicolas; Ferrand, Jérémy; Guyomar, Tristan; Museur, Flavien; Taberlet, Nicolas

    2017-11-01

    Our everyday experience of aged and defective fluorescent tubes or bulbs informs us that they may flicker and emit a clicking sound while struggling to light up. In this article, the physical mechanisms controlling the initial illumination of a functioning fluorescent tube are investigated using a simple and affordable experimental setup. Thermionic emission from the electrodes of the tube controls the startup of fluorescent tubes. The origin of the faulty startup of aged fluorescent tubes is discussed and flickering regimes using functional tubes are artificially produced using a dedicated setup that decreases electron emission by the thermionic effect in a controlled manner. The physical parameters controlling the occurrence of flickering light are discussed, and their temporal statistics are reported.

  13. Controllable preparation of microscale tubes with multiphase co-laminar flow in a double co-axial microdevice.

    Science.gov (United States)

    Lan, Wenjie; Li, Shaowei; Lu, Yangcheng; Xu, Jianhong; Luo, Guangsheng

    2009-11-21

    This article describes a simple method for the fabrication of microscale polymer tubes. A double co-axial microchannel device was designed and fabricated. Liquid/liquid/liquid multiphase co-laminar flows were realized in a microchannel by choosing working systems. Three kinds of polymeric solutions were selected as the middle phase while a polyethyleneglycol aqueous solution was used as the inner and outer phases in the microfluidic process. The outer and inner phases acted as extractants of the polymer solvent. A stable double core-annular flow was formed by optimizing the composition of the outer and inner phases, and highly uniform tubes were successfully fabricated by the solvent extraction method. Both the outer diameter of the tubes and the wall thickness could be adjusted from 300 microm to 900 microm and from 40 microm to 150 microm by varying the flux of the fluids and the rolling velocity of the collection roller. In addition, titanium dioxide (TiO2) nanoparticles were successfully encapsulated into the polymer tubes with this technique. This technology has the potential to generate hollow fiber membranes for applications in separation and reaction processes.

  14. DEVELOPMENT OF COILED TUBING STRESS ANALYSIS

    Directory of Open Access Journals (Sweden)

    Davorin Matanović

    1998-12-01

    Full Text Available The use of coiled tubing is increasing rapidly with drilling of horizontal wells. To satisfy all requirements (larger mechanical stresses, larger fluid capacities the production of larger sizes and better material qualities was developed. Stresses due to axial forces and pressures that coiled tubing is subjected are close to its performance limits. So it is really important to know and understand the behaviour of coiled tubing to avoid its break, burst or collapse in the well.

  15. Medication administration through enteral feeding tubes.

    Science.gov (United States)

    Williams, Nancy Toedter

    2008-12-15

    An overview of enteral feeding tubes, drug administration techniques, considerations for dosage form selection, common drug interactions with enteral formulas, and methods to minimize tube occlusion is given. Enteral nutrition through a feeding tube is the preferred method of nutrition support in patients who have a functioning gastrointestinal tract but who are unable to be fed orally. This method of delivering nutrition is also commonly used for administering medications when patients cannot swallow safely. However, several issues must be considered with concurrent administration of oral medications and enteral formulas. Incorrect administration methods may result in clogged feeding tubes, decreased drug efficacy, increased adverse effects, or drug-formula incompatibilities. Various enteral feeding tubes are available and are typically classified by site of insertion and location of the distal tip of the feeding tube. Liquid medications, particularly elixirs and suspensions, are preferred for enteral administration; however, these formulations may be hypertonic or contain large amounts of sorbitol, and these properties increase the potential for adverse effects. Before solid dosage forms are administered through the feeding tube, it should be determined if the medications are suitable for manipulation, such as crushing a tablet or opening a capsule. Medications should not be added directly to the enteral formula, and feeding tubes should be properly flushed with water before and after each medication is administered. To minimize drug-nutrient interactions, special considerations should be taken when administering phenytoin, carbamazepine, warfarin, fluoroquinolones, and proton pump inhibitors via feeding tubes. Precautions should be implemented to prevent tube occlusions, and immediate intervention is required when blockages occur. Successful drug delivery through enteral feeding tubes requires consideration of the tube size and placement as well as careful

  16. Unique removal of a kinked nasogastric tube

    Directory of Open Access Journals (Sweden)

    Kumar Shwetanshu Narayan

    2017-01-01

    Full Text Available Nasogastric (NG tube insertion is a common clinical procedure used for both diagnostic and therapeutic purposes. As the importance of enteral nutrition is being increasingly recognized; the use of NG tube insertion has steadily increased. Here, we present an interesting case in which a kinked NG tube was removed in a unique manner with “push and pull” technique without untoward trauma.

  17. Preparation of nitrogen-doped carbon tubes

    Science.gov (United States)

    Chung, Hoon Taek; Zelenay, Piotr

    2015-12-22

    A method for synthesizing nitrogen-doped carbon tubes involves preparing a solution of cyanamide and a suitable transition metal-containing salt in a solvent, evaporating the solvent to form a solid, and pyrolyzing the solid under an inert atmosphere under conditions suitable for the production of nitrogen-doped carbon tubes from the solid. Pyrolyzing for a shorter period of time followed by rapid cooling resulted in a tubes with a narrower average diameter.

  18. Inverse Kinematics of Concentric Tube Steerable Needles

    OpenAIRE

    Sears, Patrick; Dupont, Pierre E.

    2007-01-01

    Prior papers have introduced steerable needles composed of precurved concentric tubes. The curvature and extent of these needles can be controlled by the relative rotation and translation of the individual tubes. Under certain assumptions on the geometry and design of these needles, the forward kinematics problem can be solved in closed form by means of algebraic equations. The inverse kinematics problem, however, is not as straightforward owing to the nonlinear map between relative tube disp...

  19. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...

  20. Polymer Electronics, Quo Vadis?

    NARCIS (Netherlands)

    Chiechi, Ryan C.; Hummelen, Jan C.

    2012-01-01

    At the heart of polymer electronics lies more than three decades of research into conjugated polymers. The future of these materials is intimately tied to the development of organic photovoltaic (OPV) devices that can compete with traditional, inorganic devices in efficiency and cost. In addition to

  1. Segmented conjugated polymers

    Indian Academy of Sciences (India)

    Abstract. Segmented conjugated polymers, wherein the conjugation is randomly truncated by varying lengths of non-conjugated segments, form an interesting class of polymers as they not only represent systems of varying stiffness, but also ones where the backbone can be construed as being made up of chromophores of ...

  2. based gel polymer electrolytes

    Indian Academy of Sciences (India)

    vity at ambient temperature (Wright 1975; Martuscelli et al 1984). Generally solid polymer electrolytes have many advantages, viz. high ionic conductivity, high specific energy, wide electrochemical stability windows, light and easy processibility. Apart from this, polymer electrolyte studies have been carried out in poly(vinyl ...

  3. Stiff quantum polymers

    OpenAIRE

    Kleinert, H.

    2009-01-01

    At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

  4. Polymers targeting habitual diseases

    Science.gov (United States)

    The use of polymeric drug conjugates mainly for the treatment for cancer therapy has been addressed, but these polymers also find their way in treatment of various lifestyle disorders like diabetes, hypertension, cardiovascular diseases etc. The focus is being laid to develop biodegradable polymer ...

  5. Segmented conjugated polymers

    Indian Academy of Sciences (India)

    Segmented conjugated polymers, wherein the conjugation is randomly truncated by varying lengths of non-conjugated segments, form an interesting class of polymers as they not only represent systems of varying stiffness, but also ones where the backbone can be construed as being made up of chromophores of varying ...

  6. Micro tube heat exchangers for Space Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mezzo fabricates micro tube heat exchangers for a variety of applications, including aerospace, automotive racing, Department of Defense ground vehicles, economizers...

  7. Failure Analysis of a Service Tube

    Science.gov (United States)

    Xie, Zhongdong; Cai, Weiguo; Li, Zhenxing; Guan, YiMing; Zhang, Baocheng; Yang, XiaoTong

    2017-12-01

    One tube was cracked used in the primary reformer furnace in a fertilizer plant for two and half years. In order to find out the causes of cracking, the methods for chemical composition analysis, macro- and microstructure analysis, penetrant testing, weld analysis, crack and surface damage analysis, mechanics property analysis, high temperature endurance performance analysis, stress and wall thickness calculation were adopted. The integrated assessment results showed that the carbon content of the tube was in the lower limit of the standard range; the tube effective wall thickness was too small; local overheating leads to tube cracking in use process.

  8. Enhanced Evaporation and Condensation in Tubes

    Science.gov (United States)

    Honda, Hiroshi

    A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

  9. Organic monolith frits encased in polyether ether ketone tubing with improved durability for liquid chromatography.

    Science.gov (United States)

    Park, Sin Young; Cheong, Won Jo

    2015-09-01

    This study introduces a preparation method for polymer-encased monolith frits with improved durability for liquid chromatography columns. The inner surface of the polyether ether ketone tubing is pretreated with sulfuric acid in the presence of catalysts (vanadium oxide and sodium sulfate). The tubing was rinsed with water and acetone, flushed with nitrogen, and treated with glycidyl methacrylate. After washing, the monolith reaction mixture composed of lauryl methacrylate, ethylene glycol dimethacrylate, initiator, and porogenic solvent was filled in the tubing and subjected to in situ polymerization. The tubing was cut into thin slices and used as frits for microcolumns. To check their durability, the frit slices were placed in a vial and a heavy impact was applied on the vial by a vortex mixer for various periods. The frits made in the presence of catalysts were found to be more durable than those made without catalysts. Furthermore, when the monolith-incorporated tubing was used as a chromatography column, the column prepared in the presence of catalysts resulted in a better separation efficiency. The separation performance of the columns installed with the polyether ether ketone encased monolith frits was comparable to that of the columns installed with the commercial stainless-steel screen frits. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Ion Implantation of Polymers

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2012-01-01

    The current paper presents a state-of-the-art review in the field of ion implantation of polymers. Numerous published studies of polymers modified by ion beams are analysed. General aspects of ion stopping, latent track formation and changes of structure and composition of organic materials...... are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus...... is put on the low-energy implantation of metal ions causing the nucleation and growth of nanoparticles in the shallow polymer layers. Electrical, optical and magnetic properties of metal/polymer composites are under the discussion and the approaches towards practical applications are overviewed....

  11. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  12. All Polymer Micropump

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen

    2008-01-01

    In this thesis an all polymer micropump, and the fabrication method required to fabricate this, are examined. Polymer microfluidic. devices are of major scientific interest because they can combine complicated chemical and biological analys~s in cheap and disposable devices. The electrode system...... in the micropump is based on the conducting polymer poly(3,4 ethylenedioxythiophene) (PEDOT). The majority of the work conducted was therefore aimed at developing methods for patterning and processing PEDOT. First a method was developed, where the conducting polymer PEDOT can be integrated into non...... of the substrate, the PEDOT is integrated into the non-conductive polymer. The result is a material that retains the good conductivity of PEDOT, but gains the mechanical stability of the substrate. The best results were obtained for PEDOTjPMMA. The new mechanically stable PEDOTjPMMA was micro-patterned using clean...

  13. Generation of flux tube waves in stellar convection zones. 1: Longitudinal tube waves

    Science.gov (United States)

    Musielak, Z. E.; Rosner, R.; Ulmschneider, P.

    1987-01-01

    The source functions and the energy fluxes are derived for wave generation in magnetic flux tubes embedded in an otherwise magnetic- field free, turbulent, and compressible fluid. Specific results for the generation of longitudinal tube waves are presented.

  14. Sunspots and the physics of magnetic flux tubes. V - Mutual hydrodynamic forces between neighboring tubes

    Science.gov (United States)

    Parker, E. N.

    1979-01-01

    The mutual hydrodynamic forces between parallel cylinders in a moving fluid are illustrated through several formal examples. Parallel tubes in a uniform flow are attracted or repelled depending on whether they are side by side or one ahead of the other, respectively. A pulsating or undulating tube attracts all other neighboring tubes toward itself. These hydrodynamic effects suggest that the separate flux tubes beneath the sunspots exert significant attractive forces on each other.

  15. Preparation of organic monolithic columns in polytetrafluoroethylene tubes for reversed-phase liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Catalá-Icardo, M., E-mail: mocaic@qim.upv.es [Research Institute for Integrated Management of Coastal Areas, Universitat Politècnica de València, Paranimf 1, 46730, Grao de Gandía, Valencia (Spain); Torres-Cartas, S.; Meseguer-Lloret, S.; Gómez-Benito, C. [Research Institute for Integrated Management of Coastal Areas, Universitat Politècnica de València, Paranimf 1, 46730, Grao de Gandía, Valencia (Spain); Carrasco-Correa, E.; Simó-Alfonso, E.F.; Ramis-Ramos, G. [Department of Analytical Chemistry, Universitat de València, Dr. Moliner 50, 46100, Burjassot, Valencia (Spain); Herrero-Martínez, J.M., E-mail: jmherrer@uv.es [Department of Analytical Chemistry, Universitat de València, Dr. Moliner 50, 46100, Burjassot, Valencia (Spain)

    2017-04-01

    In this work, a method for the preparation and anchoring of polymeric monoliths in a polytetrafluoroethylene (PTFE) tubing as a column housing for microbore HPLC is described. In order to assure a covalent attachment of the monolith to the inner wall of the PTFE tube, a two-step procedure was developed. Two surface etching reagents, a commercial sodium naphthalene solution (Fluoroetch{sup ®}), or mixtures of H{sub 2}O{sub 2} and H{sub 2}SO{sub 4}, were tried and compared. Then, the obtained hydroxyl groups on the PTFE surface were modified by methacryloylation. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the tubing wall and the stable anchorage of monolith to the wall, respectively. Special emphasis was also put on the reduction of the unwanted effects of shrinking of monolith during polymerization, by using an external proper mold and by selecting the adequate monomers in order to increase the flexibility of the polymer. Poly(glycidyl methacrylate-co-divinylbenzene) monoliths were in situ synthesized by thermal polymerization within the confines of surface-vinylized PTFE tubes. The modified PTFE tubing tightly held the monolith, and the monolithic column exhibited good pressure resistance up to 20 MPa. The column performance was also evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode. The optimized monolithic columns gave plate heights ranged between 70 and 80 μm. The resulting monoliths were also satisfactorily applied to the separation of proteins. - Highlights: • Successful surface etching of PTFE inner wall tubing was done. • The modified PTFE support was next methacryloylated with GMA. • Organic polymeric monolith was in situ prepared in the functionalized PTFE tube. • The monolithic columns gave suitable pressure resistance and separation of proteins.

  16. Sugar–derived organogels as templates for structured, photoluminescent conjugated polymer-inorganic hybrid materials

    OpenAIRE

    Marr, Patricia C.; McBride, Katherine; Evans, Rachel C.

    2013-01-01

    Co-assembly of an inorganic–organic hybrid material through the combination of supramolecular organogel self-assembly, phase partitioning of a conjugated polymer (CP) and transcription of an inorganic oxide leads to a hybrid material with structured domains of organogel, CP and silica within tube and rod microstructures.

  17. Sugar-derived organogels as templates for structured, photoluminescent conjugated polymer-inorganic hybrid materials.

    Science.gov (United States)

    Marr, Patricia C; McBride, Katherine; Evans, Rachel C

    2013-07-14

    Co-assembly of an inorganic-organic hybrid material through the combination of supramolecular organogel self-assembly, phase partitioning of a conjugated polymer (CP) and transcription of an inorganic oxide leads to a hybrid material with structured domains of organogel, CP and silica within tube and rod microstructures.

  18. Working session 2: Tubing inspection

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, J. [Tecnatom, S.A. San Sebastian de los Reyes, Madrid (Spain); Tapping, R.L. [AECL, Chalk River, Ontario (Canada)

    1997-02-01

    This session was attended by delegates from 10 countries, and four papers were presented. A wide range of issues was tabled for discussion. Realizing that there was limited time available for more detailed discussion, three topics were chosen for the more detailed discussion: circumferential cracking, performance demonstration (to focus on POD and sizing), and limits of methods. Two other subsessions were organized: one dealt with some challenges related to the robustness of current inspection methods, especially with respect to leaving cracked tubes in service, and the other with developing a chart of current NDE technology with recommendations for future development. These three areas are summarized in turn, along with conclusions and/or recommendations. During the discussions there were four presentations. There were two (Canada, Japan) on eddy current probe developments, both of which addressed multiarray probes that would detect a range of flaws, one (Spain) on circumferential crack detection, and one (JRC, Petten) on the recent PISC III results.

  19. Paramecium swimming in capillary tube

    CERN Document Server

    Jana, Saikat; Jung, Sunghwan

    2010-01-01

    Swimming organisms in their natural habitat navigate through a wide array of geometries and chemical environments. Interaction with the boundaries is ubiquitous and can significantly modify the swimming characteristics of the organism as observed under ideal conditions. We study the dynamics of ciliary locomotion in Paramecium multimicronucleatum and observe the effect of the solid boundaries on the velocities in the near field of the organism. Experimental observations show that Paramecium executes helical trajectories that slowly transition to straight line motion as the diameter of the capillary tubes decrease. Theoretically this system is modeled as an undulating cylinder with pressure gradient and compared with experiments; showing that such considerations are necessary for modeling finite sized organisms in the restrictive geometries.

  20. Failure analysis of retired steam generator tubings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Pyo; Kim, J. S.; Hwang, S. S. and others

    2005-04-15

    Degradation of steam generator leads to forced outage and extension of outage, which causes increase in repair cost, cost of purchasing replacement power and radiation exposure of workers. Steam generator tube rupture incident occurred in Uljin 4 in 2002, which made public sensitive to nuclear power plant. To keep nuclear energy as a main energy source, integrity of steam generator should be demonstrated. Quantitative relationship between ECT(eddy current test) signal and crack size is needed in assesment of integrity of steam generator in pressurized water reactor. However, it is not fully established for application in industry. Retired steam generator of Kori 1 has many kinds of crack such as circumferential and axial primary water stress corrosion crack and outer diameter stress corrosion crack(ODSCC). So, it can be used in qualifying and improving ECT technology and in condition monitoring assesment for crack detected in ISI(in service inspection). In addition, examination of pulled tube of Kori 1 retired steam generator will give information about effectiveness of non welded sleeving technology which was employed to repair defect tubes and remedial action which was applied to mitigate ODSCC. In this project, hardware such as semi hot lab. for pulled tube examination and modification transportation cask for pulled tube and software such as procedure of transportation of radioactive steam generator tube and non-destructive and destructive examination of pulled tube were established. Non-destructive and destructive examination of pulled tubes from Kori 1 retired steam generator were performed in semi hot lab. Remedial actions applied to Kori 1 retired steam generator, PWSCC trend and bulk water chemistry and crevice chemistry in Kori 1 were evaluated. Electrochemical decontamination technology for pulled tube was developed to reduce radiation exposure and enhance effectiveness of pulled tube examination. Multiparameter algorithm developed at ANL, USA was

  1. Observation of "YouTube" Language Learning Videos ("YouTube" LLVS)

    Science.gov (United States)

    Alhamami, Munassir

    2013-01-01

    This paper navigates into the "YouTube" website as one of the most usable online tools to learn languages these days. The paper focuses on two issues in creating "YouTube" language learning videos: pedagogy and technology. After observing the existing "YouTube" LLVs, the study presents a novel rubric that is directed…

  2. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Science.gov (United States)

    2010-10-01

    ... (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Washing Boilers § 230.61 Arch tubes, water bar tubes, circulators and thermic siphons. (a) Frequency of cleaning. Each time the boiler is washed, arch tubes and...

  3. Sandstone-body and shale-body dimensions in a braided fluvial system: Salt wash sandstone member (Morrison formation), Garfield County, Utah

    Science.gov (United States)

    Robinson, J.W.; McCabea, P.J.

    1997-01-01

    Excellent three-dimensional exposures of the Upper Jurassic Salt Wash Sandstone Member of the Morrison Formation in the Henry Mountains area of southern Utah allow measurement of the thickness and width of fluvial sandstone and shale bodies from extensive photomosaics. The Salt Wash Sandstone Member is composed of fluvial channel fill, abandoned channel fill, and overbank/flood-plain strata that were deposited on a broad alluvial plain of low-sinuosity, sandy, braided streams flowing northeast. A hierarchy of sandstone and shale bodies in the Salt Wash Sandstone Member includes, in ascending order, trough cross-bedding, fining-upward units/mudstone intraclast conglomerates, singlestory sandstone bodies/basal conglomerate, abandoned channel fill, multistory sandstone bodies, and overbank/flood-plain heterolithic strata. Trough cross-beds have an average width:thickness ratio (W:T) of 8.5:1 in the lower interval of the Salt Wash Sandstone Member and 10.4:1 in the upper interval. Fining-upward units are 0.5-3.0 m thick and 3-11 m wide. Single-story sandstone bodies in the upper interval are wider and thicker than their counterparts in the lower interval, based on average W:T, linear regression analysis, and cumulative relative frequency graphs. Multistory sandstone bodies are composed of two to eight stories, range up to 30 m thick and over 1500 m wide (W:T > 50:1), and are also larger in the upper interval. Heterolithic units between sandstone bodies include abandoned channel fill (W:T = 33:1) and overbank/flood-plain deposits (W:T = 70:1). Understanding W:T ratios from the component parts of an ancient, sandy, braided stream deposit can be applied in several ways to similar strata in other basins; for example, to (1) determine the width of a unit when only the thickness is known, (2) create correlation guidelines and maximum correlation lengths, (3) aid in interpreting the controls on fluvial architecture, and (4) place additional constraints on input variables to

  4. Axial Compression Tests on Corroded Reinforced Concrete Columns Consolidated with Fibre Reinforced Polymers

    Directory of Open Access Journals (Sweden)

    Bin Ding

    2017-06-01

    Full Text Available Reinforced concrete structure featured by strong bearing capacity, high rigidity, good integrity, good fire resistance, and extensive applicability occupies a mainstream position in contemporary architecture. However, with the development of social economy, people need higher requirements on architectural structure; durability, especially, has been extensively researched. Because of the higher requirement on building material, ordinary reinforced concrete structure has not been able to satisfy the demand. As a result, some new materials and structures have emerged, for example, fibre reinforced polymers. Compared to steel reinforcement, fibre reinforced polymers have many advantages, such as high tensile strength, good durability, good shock absorption, low weight, and simple construction. The application of fibre reinforced polymers in architectural structure can effectively improve the durability of the concrete structure and lower the maintenance, reinforcement, and construction costs in severe environments. Based on the concepts of steel tube concrete, fibre reinforced composite material confined concrete, and fibre reinforced composite material tubed concrete, this study proposes a novel composite structure, i.e., fibre reinforced composite material and steel tube concrete composite structure. The structure was developed by pasting fibre around steel tube concrete and restraining core concrete using fibre reinforced composite material and steel tubes. The bearing capacity and ultimate deformation capacity of the structure was tested using column axial compression test.

  5. Polymer-Polymer Miscibility and Enthalpy Relaxations

    NARCIS (Netherlands)

    Bosma, Martin; Brinke, Gerrit ten; Ellis, Thomas S.

    Annealing of polymers below the glass transition temperature results in a decrease in enthalpy that is recovered during heating. The enthalpy recovery is visible as an endothermic peak in a differential scanning calorimetry (DSC) scan. The position of this peak depends on the thermal treatment given

  6. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    tures of polymer melt rheology. Large-scale protein motions on the other hand are critical for proteins to coordi- nate precise biological functions. Structural studies have documented the confor- mational flexibility in proteins accompanying their activity. Results from macro- scopic studies such as biochemical kinetics and ...

  7. Broadcast yourself on YouTube - really?

    NARCIS (Netherlands)

    Kruitbosch, G.; Nack, F.

    2008-01-01

    One essential reason for people to publish on the web is to express themselves freely. YouTube facilitates this self-expression by allowing users to upload video content they generated. This paper investigates to what extent the videos on YouTube are self-generated content, instead of amalgamated

  8. Short Communication Tube-forming polychaetes enhance ...

    African Journals Online (AJOL)

    We collected invertebrate samples from an intertidal flat with low onuphid tube density (2.7 m–2) in Mozambique and document that more organisms (70 times higher mollusc abundances) and more species (15 times more mollusc species) were found associated with solitary tubes of an onuphid polychaete compared with ...

  9. Selecting silicone tubing for device applications.

    Science.gov (United States)

    Jahn, D

    2005-10-01

    A number of factors are involved in selecting the most suitable silicone tubing for a given purpose. These include physical chemistry, performance properties, a supplier's quality system and regulatory compliance. This article provides a guide for device developers when selecting silicone tubing for their applications.

  10. Non-uniform tube representation of proteins

    DEFF Research Database (Denmark)

    Hansen, Mikael Sonne

    might not correctly capture volume exclusion - of crucial importance when trying to understand a proteins $3$d-structure. We propose a new reduced model treating the protein as a non-uniform tube with a radius reflecting the positions of atoms. The tube representation is well suited considering X...

  11. Non-Uniform Tube Representation of Proteins

    DEFF Research Database (Denmark)

    Hansen, Mikael Sonne

    might not correctly capture volume exclusion - of crucial importance when trying to understand a protein's 3d-structure. We propose a new reduced model treating the protein as a non-uniform tube with a radius reflecting the positions of atoms. The tube representation is well suited considering X...

  12. Places to Go: YouTube

    Science.gov (United States)

    Downes, Stephen

    2008-01-01

    Founded in 2005 by three former PayPal employees, YouTube has revolutionized the Internet, marking a change from the static Internet to the dynamic Internet. In this edition of Places to Go, Stephen Downes discusses how the rise of a ubiquitous media format--Flash video--has made YouTube's success possible and argues that Flash video has important…

  13. Photomultiplier tubes for Low Level Cerenkov Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O.

    1965-03-15

    Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a {beta}-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10{sup -12} input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10{sup -12} to 10{sup -9} input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses.

  14. Confined Tube Crimp Using Portable Hand Tools

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Joseph James [Los Alamos National Laboratory; Pereyra, R. A. [LANL Retired; Archuleta, Jeffrey Christopher [Los Alamos National Laboratory; Martinez, Isaac P. [Los Alamos National Laboratory; Nelson, A. M. [MST-16 Summer Student (2007); Allen, Ronald Scott [Los Alamos National Laboratory; Page, R. L. [LANL Retired; Freer, Jerry Eugene [Los Alamos National Laboratory; Dozhier, Nathan Gus [Los Alamos National Laboratory

    2016-04-04

    The Lawrence Radiation Laboratory developed handheld tools that crimp a 1/16 inch OD tube, forming a leak tight seal1 (see Figure 1). The leak tight seal forms by confining the 1/16 inch OD tubing inside a die while applying crimp pressure. Under confined pressure, the tube walls weld at the crimp. The purpose of this study was to determine conditions for fabricating a leak tight tube weld. The equipment was used on a trial-and-error basis, changing the conditions after each attempt until successful welds were fabricated. To better confine the tube, the die faces were polished. Polishing removed a few thousandths of an inch from the die face, resulting in a tighter grip on the tubing wall. Using detergent in an ultrasonic bath, the tubing was cleaned. Also, the time under crimp pressure was increased to 30 seconds. With these modifications, acceptable cold welds were fabricated. After setting the conditions for an acceptable cold weld, the tube was TIG welded across the crimped face.

  15. Sampling Artifacts from Conductive Silicone Tubing

    Energy Technology Data Exchange (ETDEWEB)

    Timko, Michael T.; Yu, Zhenhong; Kroll, Jesse; Jayne, John T.; Worsnop, Douglas R.; Miake-Lye, Richard C.; Onasch, Timothy B.; Liscinsky, David; Kirchstetter, Thomas W.; Destaillats, Hugo; Holder, Amara L.; Smith, Jared D.; Wilson, Kevin R.

    2009-05-15

    We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: 1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and 2) silicone tubing emits organic contaminants containing siloxane that adsorb onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and should, therefore, be used with caution. Gentle heating, physical and chemical properties of the particle carriers, exposure to solvents, and tubing age may influence siloxane uptake. The amount of contamination is expected to increase as the tubing surface area increases and as the particle surface area increases. The effect is observed at ambient temperature and enhanced by mild heating (<100 oC). Further evaluation is warranted.

  16. Isolated Fallopian Tube Torsion in Adolescents

    Directory of Open Access Journals (Sweden)

    S. Rajaram

    2013-01-01

    Full Text Available Background. Fallopian tube torsion is a rare cause of acute abdomen, occurring commonly in females of reproductive age. It lacks pathognomonic symptoms, signs, or imaging features, thus causing delay in surgical intervention. Case. We report two cases of isolated fallopian tube torsion in adolescent girls. In the first case a 19-year-old patient presented with acute pain in the left iliac region associated with episodes of vomiting for one day and mild tenderness on examination. Laparoscopy revealed left sided twisted fallopian tube associated with hemorrhagic cyst of ovary. The tube was untwisted and salvaged. In another case an 18-year-old virgin girl presented with similar complaints since one week, associated with mild tenderness in the lower abdomen and tender cystic mass on per rectal examination. On laparoscopy right twisted fallopian tube associated with a paratubal cyst was found. Salpingectomy was done as the tube was gangrenous. Conclusion. Fallopian tube torsion, though rare, should be considered in women of reproductive age with unilateral pelvic pain. Early diagnostic laparoscopy is important for an accurate diagnosis and could salvage the tube.

  17. A Slot Machine, A Broken Test Tube

    Indian Academy of Sciences (India)

    IAS Admin

    BOOK │ REVIEW. A Slot Machine, A Broken. Test Tube. Vinita Shivakumar and. Dipshikha Chakravortty. A Slot Machine, A Broken Test. Tube – An Autobiography. Salvador Edward Luria. Harper Collins Publishers Inc.,. USA. 1984. 1st edn. 228 pp. (Original from the University of. Michigan). Price: Rs 60/-. Salvador Edward ...

  18. Teaching Shakespeare with YouTube

    Science.gov (United States)

    Desmet, Christy

    2009-01-01

    YouTube, the video sharing website that allows viewers to upload video content ranging from cute dog tricks to rare rock videos, also supports a lively community devoted to the performance of Shakespeare and Shakespearean adaptations. YouTube is also a popular site for student producers of Shakespeare performances, parodies, and other artistic…

  19. Geotextile Tube Structures Guidelines for Contract Specifications

    Science.gov (United States)

    2006-09-01

    Nonwoven fabrics: Diaphragm Bursting Strength Tester Method ASTM D 3884 (1992) Abrasion Resistance of Textile Fabrics (Rotary Platform, Double-Head... filter cloth, excavation of borrow material, transportation of borrow material, filling of the tubes, coating of the completed tubes, disposal of waste

  20. Local Thickening of Stainless Tube Considering Dimension Variation of the Cold Roll Formed Tube Billet

    Science.gov (United States)

    Sheu, Jinn-Jong; Yu, Cheng-Hsien

    2011-01-01

    A stud end consists of tube body and a flange in order to connect two tubes to form a long straight or angled pipe line. The flange is thicker than the tube body to strengthen the pipe connection. A thicker round hollow disk is usually welded to a straight tube to get the flange of the tube end and then machined to the specified dimension of the two-piece type stud end. A one-piece type stud end of tube proposed here is produced via the local thickening of tube end, flaring, and flange forging processes. The roundness of raw tube is not promised in the cold roll forming (CRF) process, which causes the inaccuracy of dimensions, wrinkling, and folding defects during the local thickening process of tube end. In this paper, a preform process was proposed to correct the dimension of the tube to be thickened. The CRF tube billets were measured and preformed to the required dimensions before thickening. The proposed preforming process was able to resize and control the dimensions and roundness of the tube billet to prevent irregular movement of billet. A three-staged punch profile was designed to prevent the folding defect during the thickening process. Experiments of resizing and thickening were carried out to verify the simulation results and the proposed punch profile design. The CAE simulations demonstrated the defects of folding are very sensitive to the dimension variation of tube billet. The experimental results of thickening process were in good agreement with the simulation predictions using the perfect (with preforming process) and the imperfect (original CRF) tube billets. The proposed pre-forming process and the punch profile designs were able to minimize the surface defects of tube local thickening.

  1. Building lab-scale x-ray tube based irradiators

    Science.gov (United States)

    The construction of economical x-ray tube based irradiators in a variety of configurations is described using 1000 Watt x-ray tubes. Single tube, double tube, and four tube designs are described, as well as various cabinet construction techniques. Relatively high dose rates were achieved for small s...

  2. An Analysis of Nondestructive Evaluation Techniques for Polymer Matrix Composite Sandwich Materials

    Science.gov (United States)

    Cosgriff, Laura M.; Roberts, Gary D.; Binienda, Wieslaw K.; Zheng, Diahua; Averbeck, Timothy; Roth, Donald J.; Jeanneau, Philippe

    2006-01-01

    Structural sandwich materials composed of triaxially braided polymer matrix composite material face sheets sandwiching a foam core are being utilized for applications including aerospace components and recreational equipment. Since full scale components are being made from these sandwich materials, it is necessary to develop proper inspection practices for their manufacture and in-field use. Specifically, nondestructive evaluation (NDE) techniques need to be investigated for analysis of components made from these materials. Hockey blades made from sandwich materials and a flat sandwich sample were examined with multiple NDE techniques including thermographic, radiographic, and shearographic methods to investigate damage induced in the blades and flat panel components. Hockey blades used during actual play and a flat polymer matrix composite sandwich sample with damage inserted into the foam core were investigated with each technique. NDE images from the samples were presented and discussed. Structural elements within each blade were observed with radiographic imaging. Damaged regions and some structural elements of the hockey blades were identified with thermographic imaging. Structural elements, damaged regions, and other material variations were detected in the hockey blades with shearography. Each technique s advantages and disadvantages were considered in making recommendations for inspection of components made from these types of materials.

  3. Biomedical applications of polymers

    CERN Document Server

    Gebelein, C G

    1991-01-01

    The biomedical applications of polymers span an extremely wide spectrum of uses, including artificial organs, skin and soft tissue replacements, orthopaedic applications, dental applications, and controlled release of medications. No single, short review can possibly cover all these items in detail, and dozens of books andhundreds of reviews exist on biomedical polymers. Only a few relatively recent examples will be cited here;additional reviews are listed under most of the major topics in this book. We will consider each of the majorclassifications of biomedical polymers to some extent, inclu

  4. Adaptive polymer particles

    Science.gov (United States)

    Kalaitzidou, Kyriaki; Crosby, Alfred J.

    2008-07-01

    Adaptable polymer particles that can change geometry, flow characteristics, and adsorption properties upon the stimulation of an environmental change, such as temperature, are fabricated by utilizing the residual stress developed at the interface of a bilayer. We propose a phase diagram that can be used to predict the shape and size of the adaptive polymer particles as a function of the material modulus, thickness ratio, and the bilayer's lateral dimensions. The materials used are gold/titanium and polydimethylsiloxane, but the method is applicable to a wide range of material combinations. Initial demonstrations of this responsive control and its impact on properties of the adaptive polymer particles are also presented.

  5. Microstructured polymer optical fibres

    CERN Document Server

    Large, Maryanne; Barton, Geoff; van Eijkelenborg, Martijn A

    2008-01-01

    Microstructured Polymer Optical Fibres describes the optical properties of microstructured fibres, how they are made and modelled, and outlines some potential applications. These applications include areas where polymer fibres are already used, such as high-data rate transmission for Fibre-to-the Home or within cars, as well as completely new areas such as the photonic bandgap transmission of ""difficult"" wavelengths. Emphasising a conceptual understanding of the underlying physics, Microstructured Polymer Optical Fibres is clearly written, and includes numerous illustrations. It provides an

  6. Development of Silicate Polymers

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob

      The development of inorganic polymers is a new promising technology that may be used in many applications. The syntheses of inorganic polymers are normally carried out either by mixing an amorphous material for example silicium dioxide with a mineral base or dissolving metal oxids or metal...... hydroxide in acid and increase pH to saturation of the metal hydroxide. It is assumed that the syntheses of the inorganic polymer are carried out through polymerisation of oligomers (dimer, trimer) which provide the actual unit structures of the three dimensional macromolecular structure. In this work...

  7. Soluble porphyrin polymers

    Science.gov (United States)

    Gust, Jr., John Devens; Liddell, Paul Anthony

    2015-07-07

    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  8. Polymers in separation processes

    Science.gov (United States)

    Wieszczycka, Karolina; Staszak, Katarzyna

    2017-05-01

    Application of polymer materials as membranes and ion-exchange resins was presented with a focus on their use for the recovery of metal ions from aqueous solutions. Several membrane techniques were described including reverse osmosis, nanofiltration, ultrafiltration, diffusion and Donnan dialysis, electrodialysis and membrane extraction system (polymer inclusion and supported membranes). Moreover, the examples of using ion-exchange resins in metal recovery were presented. The possibility of modification of the resin was discussed, including hybrid system with metal cation or metal oxide immobilized on polymer matrices or solvent impregnated resin.

  9. Tubing-for-casing cuts tubular requirements

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, C.W. Jr.

    1974-04-01

    The tight supply of tubular goods has caused many operators to turn to tubingless completions in field wells devoid of critical downhole problems. It is possible to save up to 50% on tubular steel requirements by this technique. Other than the surface casing, the basic idea employs only one string of pipe of tubing dimensions. Such a completion is illustrated. Tubingless completions generally refer to the use of 2-7/8 in. tubing which is run and cemented as the production casing of a well. In this light, the term tubingless is a misnomer and perhaps tubing-for-casing more aptly described the idea. Tubing-for-casing completions should be considered usually for gas wells where future anticipated remedial work is minimal. However, these completions can be squeezed and normal remedial work can be accomplished with a variety of available tools. Some of the problems that should be investigated when considering a tubing-for-casing are listed and described.

  10. The Mashups of YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2013-01-01

    This article focuses on YouTube mashups and how we can understand them as a specific subgenre on YouTube. The Mashups are analysed as audiovisual recontextualizations that are given new meaning, e.g., via collaborative social communities or for individual promotional purposes. This is elaborated......, but rather in its social and communicative abilities within the YouTube community. This leads to the article’s overall argument that the main characteristic of the YouTube Mashup can be explained in terms of connectivity. It is argued that Mashups reveal a double articulation of connectivity; one...... that involves the social mechanisms of the Mashups, and another mode, which concerns the explicit embedding of structural connectivity that accentuates the medium-specific infrastructure of YouTube. This double articulation of connectivity is furthermore elaborated on by including Grusin and Bolter’s concept...

  11. Torsional Kinematic Model for Concentric Tube Robots.

    Science.gov (United States)

    Dupont, Pierre E; Lock, Jesse; Butler, Evan

    2009-05-12

    A recent approach to steerable needle design is based on combining pre-curved tubes concentrically. By rotating and extending the tubes with respect to each other, the position and orientation of the needle tip, as well as the shape of the inserted length, can be controlled. Prior models neglected torsional twisting in the curved portions of the tubes. This paper presents a mechanics model that includes torsion, applies to any number of tubes and allows curvature and stiffness to vary with arc length. While the general model is comprised of differential equations, an analytic solution is given for two tubes of constant curvature. This solution enables analytic prediction of "snap through" instability based on a single dimensionless parameter. Simulation and experiments are used to illustrate the results.

  12. Can nasal decongestants improve eustachian tube function?

    Science.gov (United States)

    Ovari, Attila; Buhr, Anne; Warkentin, Mareike; Kundt, Günther; Ehrt, Karsten; Pau, Hans-Wilhelm

    2015-01-01

    To evaluate the effect of nasal decongestants on eustachian tube (ET) opening. A prospective nonrandomized study. A tertiary referral center. Twenty-four patients (44 ears) with intact eardrums, 39 patients (43 ears) having a noninfected eardrum defect, and six patients with an upper airway infection. Nasal or intratympanal (in perforated ears) application of a nasal decongestant (xylometazoline 0.1%). Change of tube opening quality (yes or no; better or worse) measuring tube opening parameters (pressure, latency) using the Estève method and pressure equalization tests (swallowing at negative and positive external ear canal pressures). In most cases, nasal decongestion or intratympanal use of decongestants have no effect on ET opening. Improvement in tube opening is rather an exception and, in a minority of patients, a reduced ET function was evident. Our acute studies revealed no improvement in eustachian ventilatory tube function with the administration of nasal decongestants.

  13. Explosion interaction with water in a tube

    Science.gov (United States)

    Homae, T.; Sugiyama, Y.; Wakabayashi, K.; Matsumura, T.; Nakayama, Y.

    2017-02-01

    As proposed and legislated in Japan, subsurface magazines have an explosive storage chamber, a horizontal passageway, and a vertical shaft for a vent. The authors found that a small amount of water on the floor of the storage chamber mitigated blast pressure remarkably. The mitigation mechanism has been examined more closely. To examine the effect of water, the present study assesses explosions in a transparent, square cross section, and a straight tube. A high-speed camera used to observe the tube interior. Blast pressure in and around the tube was also measured. Images obtained using the high-speed camera revealed that water inside the tube did not move after the explosion. Differences between cases of tubes without water and with water were unclear. Along with blast pressure measurements, these study results suggest that blast pressure mitigation by water occurs because of interaction between the explosion and the water near the explosion point.

  14. Soft Polymers for Building up Small and Smallest Blood Supplying Systems by Stereolithography

    Directory of Open Access Journals (Sweden)

    Michael Wegener

    2012-03-01

    Full Text Available Synthesis of a homologous series of photo-polymerizable α,w-polytetrahydrofuranether-diacrylate (PTHF-DA resins is described with characterization by NMR, GPC, DSC, soaking and rheometrical measurements. The curing speeds of the resins are determined under UV light exposure. Young’s modulus and tensile strength of fully cured resins show flexible to soft material attributes dependent on the molar mass of the used linear PTHF-diacrylates. Structuring the materials by stereo lithography (SL and multiphoton polymerization (MPP leads to tubes and bifurcated tube systems with a diameter smaller than 2 mm aimed at small to smallest supplying systems with capillary dimensions. WST-1 biocompatibility tests ofm polymer extracts show nontoxic characteristics of the adapted polymers after a washing process. Some polymers show shape memory effect (SME.

  15. CNT Enabled Co-braided Smart Fabrics: A New Route for Non-invasive, Highly Sensitive & Large-area Monitoring of Composites

    Science.gov (United States)

    Luo, Sida; Wang, Yong; Wang, Guantao; Wang, Kan; Wang, Zhibin; Zhang, Chuck; Wang, Ben; Luo, Yun; Li, Liuhe; Liu, Tao

    2017-03-01

    The next-generation of hierarchical composites needs to have built-in functionality to continually monitor and diagnose their own health states. This paper includes a novel strategy for in-situ monitoring the processing stages of composites by co-braiding CNT-enabled fiber sensors into the reinforcing fiber fabrics. This would present a tremendous improvement over the present methods that excessively focus on detecting mechanical deformations and cracks. The CNT enabled smart fabrics, fabricated by a cost-effective and scalable method, are highly sensitive to monitor and quantify various events of composite processing including resin infusion, onset of crosslinking, gel time, degree and rate of curing. By varying curing temperature and resin formulation, the clear trends derived from the systematic study confirm the reliability and accuracy of the method, which is further verified by rheological and DSC tests. More importantly, upon wisely configuring the smart fabrics with a scalable sensor network, localized processing information of composites can be achieved in real time. In addition, the smart fabrics that are readily and non-invasively integrated into composites can provide life-long structural health monitoring of the composites, including detection of deformations and cracks.

  16. Simulations of Self-Expanding Braided Stent Using Macroscopic Model of NiTi Shape Memory Alloys Covering R-Phase

    Science.gov (United States)

    Frost, M.; Sedlák, P.; Kruisová, A.; Landa, M.

    2014-07-01

    Self-expanding stents or stentgrafts made from Nitinol superelastic alloy are widely used for a less invasive treatment of disease-induced localized flow constriction in the cardiovascular system. The therapy is based on insertion of a stent into a blood vessel to maintain the inner diameter of the vessel; it provides highly effective results at minimal cost and with reduced hospital stays. However, since stent is an external mechanical healing tool implemented into human body for quite a long time, information on the mechanical performance of it is of fundamental importance with respect to patient's safety and comfort. Advantageously, computational structural analysis can provide valuable information on the response of the product in an environment where in vivo experimentation is extremely expensive or impossible. With this motivation, a numerical model of a particular braided self-expanding stent was developed. As a reasonable approximation substantially reducing computational demands, the stent was considered to be composed of a set of helical springs with specific constrains reflecting geometry of the structure. An advanced constitutive model for NiTi-based shape memory alloys including R-phase transition was employed in analysis. Comparison to measurements shows a very good match between the numerical solution and experimental results. Relation between diameter of the stent and uniform radial pressure on its surface is estimated. Information about internal phase and stress state of the material during compression loading provided by the model is used to estimate fatigue properties of the stent during cyclic loading.

  17. Petrological constraints on the recycling of mafic crystal mushes, magma ascent and intrusion of braided sills in the Torres del Paine mafic complex (Patagonia)

    Science.gov (United States)

    Leuthold, Julien; Müntener, Othmar; Baumgartner, Lukas; Putlitz, Benita

    2014-05-01

    Cumulate and crystal mush disruption and reactivation are difficult to recognise in coarse grained shallow plutonic rocks. Mafic minerals included in hornblende and zoned plagioclase provide snapshots of early crystallization and cumulate formation, but are difficult to interpret in terms of the dynamics of magma ascent and possible links between silicic and mafic rock emplacement. We will present the field relations, the microtextures and the mineral chemistry of the Miocene mafic sill complex of the Torres del Paine intrusive complex (Patagonia, Chile) and its sub-vertical feeder-zone. The mafic sill complex was built up by a succession of braided sills of shoshonitic and high-K calc-alkaline porphyritic hornblende-gabbro and fine grained monzodioritic sills. The mafic units were over-accreted over 41±11 ka, underplating the overlying granite. Local diapiric structures and felsic magma accumulation between sills indicate limited separation of intercumulus liquid from the mafic sills. Anhedral hornblende cores, with olivine + clinopyroxene ± plagioclase ± apatite inclusions, crystallized at temperatures >900°C and pressures of ~300 to ~500 MPa. The corresponding rims and monzodiorite matrix crystallized at 950°C) from the middle crust reservoir to the emplacement level. We show that hornblende-plagioclase thermobarometry is a useful monitor for the determination of segregation conditions of granitic magmas from gabbroic crystal mushes, and for monitoring the evolution of shallow crustal magmatic crystallization, decompression and cooling.

  18. Reactive polymer fused deposition manufacturing

    Science.gov (United States)

    Kunc, Vlastimil; Rios, Orlando; Love, Lonnie J.; Duty, Chad E.; Johs, Alexander

    2017-05-16

    Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.

  19. Dendritic Polymers for Theranostics.

    Science.gov (United States)

    Ma, Yuan; Mou, Quanbing; Wang, Dali; Zhu, Xinyuan; Yan, Deyue

    2016-01-01

    Dendritic polymers are highly branched polymers with controllable structures, which possess a large population of terminal functional groups, low solution or melt viscosity, and good solubility. Their size, degree of branching and functionality can be adjusted and controlled through the synthetic procedures. These tunable structures correspond to application-related properties, such as biodegradability, biocompatibility, stimuli-responsiveness and self-assembly ability, which are the key points for theranostic applications, including chemotherapeutic theranostics, biotherapeutic theranostics, phototherapeutic theranostics, radiotherapeutic theranostics and combined therapeutic theranostics. Up to now, significant progress has been made for the dendritic polymers in solving some of the fundamental and technical questions toward their theranostic applications. In this review, we briefly summarize how to control the structures of dendritic polymers, the theranostics-related properties derived from their structures and their theranostics-related applications.

  20. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.