WorldWideScience

Sample records for sub-nanometer axial localization

  1. Ultra-stable and versatile widefield cryo-fluorescence microscope for single-molecule localization with sub-nanometer accuracy.

    Science.gov (United States)

    Li, Weixing; Stein, Simon C; Gregor, Ingo; Enderlein, Jörg

    2015-02-09

    We developed a stand-alone cryostat with optical access to the sample which can be adapted to any epi-fluorescence microscope for single-molecule fluorescence spectroscopy and imaging. The cryostat cools the sample to a cryogenic temperature of 89 K, and allows for imaging single molecules using an air objective with a numerical aperture of 0.7. An important property of this system is its excellent thermal and mechanical stability, enabling long-time observations of samples over several hours with negligible drift. Using this system, we performed photo-bleaching studies of Atto647N dye molecules, and find an improvement of the photostability of these molecules by more than two orders of magnitude. The resulting increased photon numbers of several millions allow for single-molecule localization accuracy of sub-nanometer.

  2. Sub-nanometer drift correction for super-resolution imaging.

    Science.gov (United States)

    Tang, Y; Wang, X; Zhang, X; Li, J; Dai, L

    2014-10-01

    Spatial resolution of conventional far-field fluorescence microscopy is limited by diffraction of light. Single-molecule localization microscopy (SMLM), such as (direct) stochastic optical reconstruction microscopy (dSTORM/STORM), and (fluorescence) photoactivation localization microscopy (fPALM/PALM), can break this barrier by localizing single emitters and reconstructing super-resolution image with much higher precision. Nevertheless, a SMLM measurement needs to record a large number of image frames and takes considerable recording time. In this process, sample drift becomes a critical problem and cannot be neglected. In this Letter, we present a sub-nanometer precision, low-cost sample drift correction method based on minimizing normalized root-mean-square error (NRMSE) between bright field images. Two optical configurations are suggested for recording bright field and fluorescence images simultaneously or alternately. The method was demonstrated on simulated data, and better than 0.3 nm drift correction precision was achieved. It was also applied on dSTORM imaging of F-actins of 3T3 cell, and the quality of reconstructed super-resolution image was improved observably. This method does not require special hardware, extra labelling or markers, and no precision decline due to photobleaching. It can be applied as an add-on for SMLM setups and achieves sub-nanometer precision drift correction for post-measurement or real time drift compensation.

  3. Sub-Nanometer Channels Embedded in Two-Dimensional Materials

    KAUST Repository

    Han, Yimo

    2017-07-31

    Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically-thin p-n junctions2-7, metal-semiconductor contacts8-10, and metal-insulator barriers11-13 have been demonstrated. While 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions are also necessary. Although external one-dimensional (1D) carbon nanotubes14 can be used to locally gate 2D materials, this adds a non-trivial third dimension, complicating device integration and flexibility. Here, we report the direct synthesis of sub-nanometer 1D MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalyzed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Molecular dynamics (MD) simulations have identified other combinations of 2D materials that could form 1D channels. Density function theory (DFT) calculation predicts these 1D channels display type II band alignment needed for carrier confinement and charge separation to access the ultimate length scales necessary for future electronic applications.

  4. Complex biomembrane mimetics on the sub-nanometer scale.

    Science.gov (United States)

    Heberle, Frederick A; Pabst, Georg

    2017-08-01

    Biomimetic lipid vesicles are indispensable tools for gaining insight into the biophysics of cell physiology on the molecular level. The level of complexity of these model systems has steadily increased, and now spans from domain-forming lipid mixtures to asymmetric lipid bilayers. Here, we review recent progress in the development and application of elastic neutron and X-ray scattering techniques for studying these systems in situ and under physiologically relevant conditions on the nanometer to sub-nanometer length scales. In particular, we focus on: (1) structural details of coexisting liquid-ordered and liquid-disordered domains, including their thickness and lipid packing mismatch as a function of a size transition from nanoscopic to macroscopic domains; (2) membrane-mediated protein partitioning into lipid domains; (3) the role of the aqueous medium in tuning interactions between membranes and domains; and (4) leaflet-specific structure in asymmetric bilayers and passive lipid flip-flop.

  5. Sub-nanometer resolution XPS depth profiling: Sensing of atoms

    Energy Technology Data Exchange (ETDEWEB)

    Szklarczyk, Marek, E-mail: szklarcz@chem.uw.edu.pl [Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw (Poland); Shim-Pol, ul. Lubomirskiego 5, 05-080 Izabelin (Poland); Macak, Karol; Roberts, Adam J. [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom); Takahashi, Kazuhiro [Kratos XPS Section, Shimadzu Corp., 380-1 Horiyamashita, Hadano, Kanagawa 259-1304 (Japan); Hutton, Simon [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom); Głaszczka, Rafał [Shim-Pol, ul. Lubomirskiego 5, 05-080 Izabelin (Poland); Blomfield, Christopher [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom)

    2017-07-31

    Highlights: • Angle resolved photoelectron depth profiling of nano thin films. • Sensing atomic position in SAM films. • Detection of direction position of adsorbed molecules. - Abstract: The development of a method capable of distinguishing a single atom in a single molecule is important in many fields. The results reported herein demonstrate sub-nanometer resolution for angularly resolved X-ray photoelectron spectroscopy (ARXPS). This is made possible by the incorporation of a Maximum Entropy Method (MEM) model, which utilize density corrected electronic emission factors to the X-ray photoelectron spectroscopy (XPS) experimental results. In this paper we report on the comparison between experimental ARXPS results and reconstructed for both inorganic and organic thin film samples. Unexpected deviations between experimental data and calculated points are explained by the inaccuracy of the constants and standards used for the calculation, e.g. emission factors, scattering intensity and atomic density through the studied thickness. The positions of iron, nitrogen and fluorine atoms were determined in the molecules of the studied self-assembled monolayers. It has been shown that reconstruction of real spectroscopic data with 0.2 nm resolution is possible.

  6. Sub-nanometer resolution XPS depth profiling: Sensing of atoms

    Science.gov (United States)

    Szklarczyk, Marek; Macak, Karol; Roberts, Adam J.; Takahashi, Kazuhiro; Hutton, Simon; Głaszczka, Rafał; Blomfield, Christopher

    2017-07-01

    The development of a method capable of distinguishing a single atom in a single molecule is important in many fields. The results reported herein demonstrate sub-nanometer resolution for angularly resolved X-ray photoelectron spectroscopy (ARXPS). This is made possible by the incorporation of a Maximum Entropy Method (MEM) model, which utilize density corrected electronic emission factors to the X-ray photoelectron spectroscopy (XPS) experimental results. In this paper we report on the comparison between experimental ARXPS results and reconstructed for both inorganic and organic thin film samples. Unexpected deviations between experimental data and calculated points are explained by the inaccuracy of the constants and standards used for the calculation, e.g. emission factors, scattering intensity and atomic density through the studied thickness. The positions of iron, nitrogen and fluorine atoms were determined in the molecules of the studied self-assembled monolayers. It has been shown that reconstruction of real spectroscopic data with 0.2 nm resolution is possible.

  7. Buckling localization in a cylindrical panel under axial compression

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2000-01-01

    Localization of an initially periodic buckling pattern is investigated for an axially compressed elastic-plastic cylindrical panel of the type occurring between axial stiffeners on cylindrical shells. The phenomenon of buckling localization and its analogy with plastic flow localization in tensile...... test specimens is discussed in general. For the cylindrical panel, it is shown that buckling localization develops shortly after a maximum load has been attained, and this occurs for a purely elastic panel as well as for elastic-plastic panels. In a case where localization occurs after a load maximum...

  8. Insight into Ion Transfer through the Sub-Nanometer Channels in Zeolitic Imidazolate Frameworks.

    Science.gov (United States)

    Jiang, Ze-Yu; Liu, Hai-Ling; Ahmed, Saud Asif; Hanif, Sumaira; Ren, Shi-Bin; Xu, Jing-Juan; Chen, Hong-Yuan; Xia, Xing-Hua; Wang, Kang

    2017-04-18

    A crack-free sub-nanometer composite structure for the study of ion transfer was constructed by in situ growth of ZIF-90 [Zn(ICA)2 , ICA=Imidazole-2-carboxaldehyde] on the tip of a glass nanopipette. The potential-driven ion transfer through the sub-nanometer channels in ZIF-90 is strongly influenced by the pH of the solution. A rectification ratio over 500 is observed in 1 m KCl solution under alkaline conditions (pH 11.58), which is the highest value reported under such a high salt concentration. Fluorescence experiments show the super-high rectification ratio under alkaline conditions results from the strong electrostatic interaction between ions and the sub-nanometer channels of ZIF-90. In addition to providing a general pathway for further study of mass-transfer process through sub-nanometer channels, the approach enable all kinds of metal-organic frameworks (MOFs) to be used as ionic permselectivity materials in nanopore-based analysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Figuring large optics at the sub-nanometer level: compensation for coating and gravity distortions.

    Science.gov (United States)

    Gensemer, Stephen; Gross, Mark

    2015-11-30

    Large, precision optics can now be manufactured with surface figures specified at the sub-nanometer level. However, coatings and gravity deform large optics, and there are limits to what can be corrected by clever compensation. Instead, deformations caused by stress from optical mounts and deposited coatings must be incorporated into the optical design. We demonstrate compensation of coating stress on a 370mm substrate to λ/200 by a process of coating and annealing. We also model the same process and identify the leading effects that must be anticipated in fabrication of optics for future gravitational wave detectors and other applications of large, precisely figured optics, and identify the limitations inherent in using coatings to compensate for these deformations.

  10. Bimetallic Ag-Pt Sub-nanometer Supported Clusters as Highly Efficient and Robust Oxidation Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Negreiros, Fabio R. [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Halder, Avik [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Yin, Chunrong [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Singh, Akansha [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Barcaro, Giovanni [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Sementa, Luca [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Tyo, Eric C. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Pellin, Michael J. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Bartling, Stephan [Institut für Physik, Universität Rostock, Rostock Germany; Meiwes-Broer, Karl-Heinz [Institut für Physik, Universität Rostock, Rostock Germany; Seifert, Sönke [X-ray Science Division, Argonne National Laboratory, Lemont IL USA; Sen, Prasenjit [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Nigam, Sandeep [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Fukui, Nobuyuki [East Tokyo Laboratory, Genesis Research Institute, Inc., Ichikawa Chiba 272-0001 Japan; Yasumatsu, Hisato [Cluster Research Laboratory, Toyota Technological Institute: in, East Tokyo Laboratory, Genesis Research Institute, Inc. Ichikawa, Chiba 272-0001 Japan; Vajda, Stefan [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Nanoscience and Technology Division, Argonne National Laboratory, Lemont IL USA; Institute for Molecular Engineering, University of Chicago, Chicago IL USA; Fortunelli, Alessandro [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Materials and Process Simulation Center, California Institute of Technology, Pasadena CA USA

    2017-12-29

    A combined experimental and theoretical investigation of Ag-Pt sub-nanometer clusters as heterogeneous catalysts in the CO -> CO2 reaction (COox) is presented. Ag9Pt2 and Ag9Pt3 clusters are size-selected in the gas phase, deposited on an ultrathin amorphous alumina support, and tested as catalysts experimentally under realistic conditions and by first-principles simulations at realistic coverage. Insitu GISAXS/TPRx demonstrates that the clusters do not sinter or deactivate even after prolonged exposure to reactants at high temperature, and present comparable, extremely high COox catalytic efficiency. Such high activity and stability are ascribed to a synergic role of Ag and Pt in ultranano-aggregates, in which Pt anchors the clusters to the support and binds and activates two CO molecules, while Ag binds and activates O-2, and Ag/Pt surface proximity disfavors poisoning by CO or oxidized species.

  11. Helium Ion Microscopy (HIM) for the imaging of biological samples at sub-nanometer resolution

    Science.gov (United States)

    Joens, Matthew S.; Huynh, Chuong; Kasuboski, James M.; Ferranti, David; Sigal, Yury J.; Zeitvogel, Fabian; Obst, Martin; Burkhardt, Claus J.; Curran, Kevin P.; Chalasani, Sreekanth H.; Stern, Lewis A.; Goetze, Bernhard; Fitzpatrick, James A. J.

    2013-01-01

    Scanning Electron Microscopy (SEM) has long been the standard in imaging the sub-micrometer surface ultrastructure of both hard and soft materials. In the case of biological samples, it has provided great insights into their physical architecture. However, three of the fundamental challenges in the SEM imaging of soft materials are that of limited imaging resolution at high magnification, charging caused by the insulating properties of most biological samples and the loss of subtle surface features by heavy metal coating. These challenges have recently been overcome with the development of the Helium Ion Microscope (HIM), which boasts advances in charge reduction, minimized sample damage, high surface contrast without the need for metal coating, increased depth of field, and 5 angstrom imaging resolution. We demonstrate the advantages of HIM for imaging biological surfaces as well as compare and contrast the effects of sample preparation techniques and their consequences on sub-nanometer ultrastructure. PMID:24343236

  12. Microbubble Axial Localization Errors in Ultrasound Super-Resolution Imaging.

    Science.gov (United States)

    Christensen-Jeffries, Kirsten; Harput, Sevan; Brown, Jemma; Wells, Peter N T; Aljabar, Paul; Dunsby, Chris; Tang, Meng-Xing; Eckersley, Robert J

    2017-08-17

    Acoustic super-resolution imaging has allowed visualization of microvascular structure and flow beyond the diffraction limit using standard clinical ultrasound systems through the localization of many spatially isolated microbubble signals. The determination of each microbubble position is typically performed by calculating the centroid, finding a local maximum, or finding the peak of a 2-D Gaussian function fit to the signal. However, the backscattered signal from a microbubble depends not only on diffraction characteristics of the waveform, but also on the microbubble behavior in the acoustic field. Here, we propose a new axial localization method by identifying the onset of the backscattered signal. We compare the accuracy of localization methods using in vitro experiments performed at 7 cm depth and 2.3 MHz center frequency. We corroborate these findings with simulated results based on the Marmottant model. We show experimentally and in simulations that detecting the onset of the returning signal provides considerably increased accuracy for super-resolution. Resulting experimental cross-sectional profiles in super-resolution images demonstrate at least 5.8 times improvement in contrast ratio and more than 1.8 reduction in spatial spread (provided by 90% of the localizations) for the onset method over centroiding, peak detection and 2D Gaussian fitting methods. Simulations estimate that these latter methods could create errors in relative bubble positions as high as 900 μ m at these experimental settings, while the onset method reduced the interquartile range of these errors by a factor of over 2.2. Detecting the signal onset is therefore expected to considerably improve the accuracy of super-resolution.

  13. Sub-nanometer dimensions control of core/shell nanoparticles prepared by atomic layer deposition.

    Science.gov (United States)

    Weber, M J; Verheijen, M A; Bol, A A; Kessels, W M M

    2015-03-06

    Bimetallic core/shell nanoparticles (NPs) are the subject of intense research due to their unique electronic, optical and catalytic properties. Accurate and independent control over the dimensions of both core and shell would allow for unprecedented catalytic performance. Here, we demonstrate that both core and shell dimensions of Pd/Pt core/shell nanoparticles (NPs) supported on Al2O3 substrates can be controlled at the sub-nanometer level by using a novel strategy based on atomic layer deposition (ALD). From the results it is derived that the main conditions for accurate dimension control of these core/shell NPs are: (i) a difference in surface energy between the deposited core metal and the substrate to obtain island growth; (ii) a process yielding linear growth of the NP cores with ALD cycles to obtain monodispersed NPs with a narrow size distribution; (iii) a selective ALD process for the shell metal yielding a linearly increasing thickness to obtain controllable shell growth exclusively on the cores. For Pd/Pt core/shell NPs it is found that a minimum core diameter of 1 nm exists above which the NP cores are able to catalytically dissociate the precursor molecules for shell growth. In addition, initial studies on the stability of these core/shell NPs have been carried out, and it has been demonstrated that core/shell NPs can be deposited by ALD on high aspect ratio substrates such as nanowire arrays. These achievements show therefore that ALD has significant potential for the preparation of tuneable heterogeneous catalyst systems.

  14. Influence of Thread Root Radius on Maximum Local Stresses at Large Diameter Bolts under Axial Loading

    Directory of Open Access Journals (Sweden)

    Cojocaru Vasile

    2014-06-01

    Full Text Available In the thread root area of the threaded bolts submitted to axial loading occur local stresses, higher that nominal stresses calculated for the bolts. These local stresses can generate failure and can reduce the fatigue life of the parts. The paper is focused on the study of the influence of the thread root radius on the maximum local stresses. A large diameter trapezoidal bolt was subjected to a static analysis (axial loading using finite element simulation.

  15. Mechanism and Prediction of Gas Permeation through Sub-Nanometer Graphene Pores: Comparison of Theory and Simulation.

    Science.gov (United States)

    Yuan, Zhe; Govind Rajan, Ananth; Misra, Rahul Prasanna; Drahushuk, Lee W; Agrawal, Kumar Varoon; Strano, Michael S; Blankschtein, Daniel

    2017-08-22

    Due to its atomic thickness, porous graphene with sub-nanometer pore sizes constitutes a promising candidate for gas separation membranes that exhibit ultrahigh permeances. While graphene pores can greatly facilitate gas mixture separation, there is currently no validated analytical framework with which one can predict gas permeation through a given graphene pore. In this work, we simulate the permeation of adsorptive gases, such as CO2 and CH4, through sub-nanometer graphene pores using molecular dynamics simulations. We show that gas permeation can typically be decoupled into two steps: (1) adsorption of gas molecules to the pore mouth and (2) translocation of gas molecules from the pore mouth on one side of the graphene membrane to the pore mouth on the other side. We find that the translocation rate coefficient can be expressed using an Arrhenius-type equation, where the energy barrier and the pre-exponential factor can be theoretically predicted using the transition state theory for classical barrier crossing events. We propose a relation between the pre-exponential factor and the entropy penalty of a gas molecule crossing the pore. Furthermore, on the basis of the theory, we propose an efficient algorithm to calculate CO2 and CH4 permeances per pore for sub-nanometer graphene pores of any shape. For the CO2/CH4 mixture, the graphene nanopores exhibit a trade-off between the CO2 permeance and the CO2/CH4 separation factor. This upper bound on a Robeson plot of selectivity versus permeance for a given pore density is predicted and described by the theory. Pores with CO2/CH4 separation factors higher than 10(2) have CO2 permeances per pore lower than 10(-22) mol s(-1) Pa(-1), and pores with separation factors of ∼10 have CO2 permeances per pore between 10(-22) and 10(-21) mol s(-1) Pa(-1). Finally, we show that a pore density of 10(14) m(-2) is required for a porous graphene membrane to exceed the permeance-selectivity upper bound of polymeric materials

  16. Self-assembling organic nanotubes with precisely defined, sub-nanometer pores: formation and mass transport characteristics.

    Science.gov (United States)

    Gong, Bing; Shao, Zhifeng

    2013-12-17

    The transport of molecules and ions across nanometer-scaled pores, created by natural or artificial molecules, is a phenomenon of both fundamental and practical significance. Biological channels are the most remarkable examples of mass transport across membranes and demonstrate nearly exclusive selectivity and high efficiency with a diverse collection of molecules. These channels are critical for many basic biological functions, such as membrane potential, signal transduction, and osmotic homeostasis. If such highly specific and efficient mass transport or separation could be achieved with artificial nanostructures under controlled conditions, they could create revolutionary technologies in a variety of areas. For this reason, investigators from diverse disciplines have vigorously studied small nondeformable nanopores. The most exciting studies have focused on carbon nanotubes (CNTs), which have exhibited fast mass transport and high ion selectivity despite their very simple structure. However, the limitations of CNTs and the dearth of other small (≤2 nm) nanopores have severely hampered the systematic investigation of nanopore-mediated mass transport, which will be essential for designing artificial nanopores with desired functions en masse. Researchers can overcome the difficulties associated with CNT and other artificial pores by stacking macrocyclic building blocks with persistent shapes to construct tunable, self-assembling organic pores. This effort started when we discovered a highly efficient, one-pot macrocyclization process to efficiently prepare several classes of macrocycles with rigid backbones containing nondeformable cavities. Such macrocycles, if stacked atop one another, should lead to nanotubular assemblies with defined inner pores determined by their constituent macrocycles. One class of macrocycles with aromatic oligoamide backbones had a very high propensity for directional assembly, forming nanotubular structures containing nanometer and sub-nanometer

  17. Effect of electric field gradient on sub-nanometer spatial resolution of tip-enhanced Raman spectroscopy.

    Science.gov (United States)

    Meng, Lingyan; Yang, Zhilin; Chen, Jianing; Sun, Mengtao

    2015-03-18

    Tip-enhanced Raman spectroscopy (TERS) with sub-nanometer spatial resolution has been recently demonstrated experimentally. However, the physical mechanism underlying is still under discussion. Here we theoretically investigate the electric field gradient of a coupled tip-substrate system. Our calculations suggest that the ultra-high spatial resolution of TERS can be partially attributed to the electric field gradient effect owning to its tighter spatial confinement and sensitivity to the infrared (IR)-active of molecules. Particularly, in the case of TERS of flat-lying H₂TBPP molecules,we find the electric field gradient enhancement is the dominating factor for the high spatial resolution, which qualitatively coincides with previous experimental report. Our theoretical study offers a new paradigm for understanding the mechanisms of the ultra-high spatial resolution demonstrated in tip-enhanced spectroscopy which is of importance but neglected.

  18. Differential optical shadow sensor for sub-nanometer displacement measurement and its application to drag-free satellites.

    Science.gov (United States)

    Zoellner, Andreas; Tan, Si; Saraf, Shailendhar; Alfauwaz, Abdul; DeBra, Dan; Buchman, Sasha; Lipa, John A

    2017-10-16

    We present a method for 3D sub-nanometer displacement measurement using a set of differential optical shadow sensors. It is based on using pairs of collimated beams on opposite sides of an object that are partially blocked by it. Applied to a sphere, our 3-axis sensor module consists of 8 parallel beam-detector sets for redundancy. The sphere blocks half of each beam's power in the nominal centered position, and any displacement can be measured by the differential optical power changes amongst the pairs of detectors. We have experimentally demonstrated a displacement sensitivity of 0.87nm/Hz at 1 Hz and 0.39nm/Hz at 10 Hz. We describe the application of the module to the inertial sensor of a drag-free satellite, which can potentially be used for navigation, geodesy and fundamental science experiments as well as ground based applications.

  19. Chemical vapor deposition-prepared sub-nanometer Zr clusters on Pd surfaces: promotion of methane dry reforming.

    Science.gov (United States)

    Mayr, Lukas; Shi, Xue-Rong; Köpfle, Norbert; Milligan, Cory A; Zemlyanov, Dmitry Y; Knop-Gericke, Axel; Hävecker, Michael; Klötzer, Bernhard; Penner, Simon

    2016-11-23

    An inverse Pd-Zr model catalyst was prepared by chemical vapor deposition (CVD) using zirconium-t-butoxide (ZTB) as an organometallic precursor. Pd-Zr interaction was then investigated with focus on the correlation of reforming performance with the oxidation state of Zr. As test reactions, dry reforming of methane (DRM) and methanol steam reforming (MSR) were chosen. Depending on treatments, either ZrOxHy or ZrO2 overlayers or Zr as sub-nanometer clusters could be obtained. Following the adsorption of ZTB on Pd(111), a partially hydroxylated Zr4+-containing layer was formed, which can be reduced to metallic Zr by thermal annealing in ultrahigh vacuum, leading to redox-active Zr0 sub-nanometer clusters. Complementary density functional theoretical (DFT) calculations showed that a single layer of ZrO2 on Pd(111) can be more easily reduced toward the metallic state than a double- and triple layer. Also, the initial and resulting layer compositions greatly depend on gas environment. The lower the water background partial pressure, the faster and more complete the reduction of Zr4+ species to Zr0 on Pd takes place. Under methanol steam reforming conditions, water activation by hydroxylation of Zr occurs. In excess of methanol, strong coking is induced by the Pd/ZrOxHy interface. In contrast, dry reforming of methane is effectively promoted if these initially metallic Zr species are present in the pre-catalyst, leading to a Pd/ZrOxHy phase boundary by oxidative activation under reaction conditions. These reaction-induced active sites for DRM are stable with respect to carbon blocking or coking. In essence, Zr doping of Pd opens specific CO2 activation channels, which are absent on pure metallic Pd.

  20. Direct sub-nanometer scale electron microscopy analysis of anion incorporation to self-ordered anodic alumina layers

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rovira, L.; Lopez-Haro, M.; Hungria, A.B.; El Amrani, K. [Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, University of Cadiz, Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain); Sanchez-Amaya, J.M. [Titania, Ensayos y Proyectos Industriales, S.L. Parque Tecnobahia, Edificio RETSE, Nave 4, 11500 El Puerto de Santa Maria (Cadiz) (Spain); Calvino, J.J. [Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, University of Cadiz, Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain); Botana, F.J., E-mail: javier.botana@uca.e [Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, University of Cadiz, Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain)

    2010-11-15

    Research highlights: {yields} Morphological and chemical characterization at atomic scale of porous alumina layers anodised in ordered regimes. {yields} Characterization based on the use of FEG-SEM, STEM-HAADF, STEM-EELS and STEM-X-EDS. {yields} Nanoscale distribution of P-, C- and S-bearing species in the pore wall. - Abstract: Ordered porous alumina layers prepared by two-step anodising in phosphoric, oxalic and sulphuric acids have been characterized at sub-nanometer scale using electron microscopy techniques. FEG-SEM and STEM-HAADF images allowed estimating the pore size, cell wall and pore wall thicknesses of the layers. Nanoanalytical characterization has been performed by STEM-EELS and STEM-X-EDS. Detailed features of the spatial distribution of anions in the pore wall of the films have been obtained. Maximum concentration of P-species occurs, approximately, at the middle of the pore wall; adjacent to the pore for C-species, whereas the distribution of S-species appears to be uniform.

  1. uper-resolution Axial Localization of Ultrasound Scatter Using Multi-focal Imaging

    DEFF Research Database (Denmark)

    Diamantis, Konstantinos; Greenaway, Alan H.; Anderson, Tom

    2017-01-01

    and the simple, aberration dependent, image sharpness metric of a single point scatterer. The localization of a point scatterer relies on the generation of multiple overlapping sharpness curves, created by deploying three foci during receive processing, and by assessing the sharpness values after each......This paper aims to develop a method for achieving micrometre axial scatterer localization for medical ultrasound, surpassing the inherent, pulse length dependence limiting ultrasound imaging. Methods: The method, directly translated from cellular microscopy, is based on multi-focal imaging...... to noise ratio in each image. Conclusion: Super-resolution axial imaging from optical microscopy has been successfully translated into ultrasound imaging by using raw ultrasound data and standard beamforming. Significance: The normalized sharpness method has the potential to be used in scatterer...

  2. Myelinated nerve fiber-associated local scleral excavation and induced axial myopia.

    Science.gov (United States)

    Oh, Baek-Lok; Hwang, Jeong-Min; Woo, Se Joon

    2014-10-01

    To investigate the association between the distributions of local scleral excavation and myelinated nerve fibers (MNF) and to elucidate the pathogenic mechanism of axial myopia in eyes with MNF. In six eyes of six pediatric patients with MNF, the distribution of the MNF on fundus photography was compared with the regional excavation of the sclera on linear scans across the fovea and a peripapillary circular scan of spectral domain optical coherence tomography. The tilting of Bruch membrane on vertical scan of spectral domain optical coherence tomography was associated with the major distribution of MNF (κ = 1, Cohen's kappa coefficient). The area of MNF of 12 clock-hour segments and focal scleral excavation on circular scan of spectral domain optical coherence tomography were significantly correlated (P excavation was strongly associated with the distribution of the MNF. This result indicates that the retinal areas deprived of visual stimulation by the MNF contribute to the development of axial myopia through local effects on the underlying sclera in early life.

  3. Improvement in Scoliosis Top View: Evaluation of Vertebrae Localization in Scoliotic Spine-Spine Axial Presentation

    Directory of Open Access Journals (Sweden)

    Paweł Główka

    2016-11-01

    Full Text Available Morphological analysis of the scoliotic spine is based on two-dimensional X-rays: coronal and sagittal. The three-dimensional character of scoliosis has raised the necessity for analyzing scoliosis in three planes. We proposed a new user-friendly method of graphical presentation of the spine in the third plane–the Spine Axial Presentation (SAP. Eighty-five vertebrae of patients with scoliosis were analyzed. Due to different positions during X-rays (standing and computer tomography (CT (supine, the corresponding measurements cannot be directly compared. As a solution, a software creating Digital Reconstructed Radiographs (DRRs from CT scans was developed to replace regular X-rays with DRRs. Based on the measurements performed on DRRs, the coordinates of vertebral bodies central points were defined. Next, the geometrical centers of vertebral bodies were determined on CT scans. The reproducibility of measurements was tested with Intraclass Correlation Coefficient (ICC, using p = 0.05. The intra-observer reproducibility and inter-observer reliability for vertebral body central point’s coordinates (x, y, z were high for results obtained based on DRRs and CT scans, as well as for comparison results obtained based on DRR and CT scans. Based on two standard radiographs, it is possible to localize vertebral bodies in 3D space. The position of vertebral bodies can be present in the Spine Axial Presentation.

  4. Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO2 transformation

    Science.gov (United States)

    Shanmugam, Ramasamy; Thamaraichelvan, Arunachalam; Ganesan, Tharumeya Kuppusamy; Viswanathan, Balasubramanian

    2017-02-01

    Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO2 to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO2 to CO at an applied potential of -0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO2 to various value added chemicals.

  5. SI-traceable absolute distance measurement over more than 800 meters with sub-nanometer interferometry by two-color inline refractivity compensation

    Science.gov (United States)

    Meiners-Hagen, Karl; Meyer, Tobias; Mildner, Jutta; Pollinger, Florian

    2017-11-01

    In this work, we demonstrate two-color inline refractivity compensation in a heterodyne synthetic wavelength interferometer for a measurement of absolute distances over several hundred meters with sub-millimeter accuracy. Two frequency-doubled Nd:YAG lasers with a coherence length of more than 1 km are used as light sources. Direct SI traceability is achieved by controlling the lasers' frequency difference in the radio frequency regime. The resulting synthetic wavelengths at 532 nm and 1064 nm are used for the absolute distance measurement and dispersion-based inline refractive index compensation. A standard deviation of 50 μm is achieved for distances up to 864 m. This performance corresponds to a standard deviation of the observable, the difference of the four optical wavelengths, on a sub-nanometer level. Comparison against white light interferometry confirms sub-millimeter accuracy over this distance. Temporally resolved data over 864 m provide quantitative insights into the influence of chromatic beam paths.

  6. Sub-nanometer surface chemistry and orbital hybridization in lanthanum-doped ceria nano-catalysts revealed by 3D electron microscopy.

    Science.gov (United States)

    Collins, Sean M; Fernandez-Garcia, Susana; Calvino, José J; Midgley, Paul A

    2017-07-14

    Surface chemical composition, electronic structure, and bonding characteristics determine catalytic activity but are not resolved for individual catalyst particles by conventional spectroscopy. In particular, the nano-scale three-dimensional distribution of aliovalent lanthanide dopants in ceria catalysts and their effect on the surface electronic structure remains unclear. Here, we reveal the surface segregation of dopant cations and oxygen vacancies and observe bonding changes in lanthanum-doped ceria catalyst particle aggregates with sub-nanometer precision using a new model-based spectroscopic tomography approach. These findings refine our understanding of the spatially varying electronic structure and bonding in ceria-based nanoparticle aggregates with aliovalent cation concentrations and identify new strategies for advancing high efficiency doped ceria nano-catalysts.

  7. Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO{sub 2} transformation

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, Ramasamy [Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625 009 (India); National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India); Thamaraichelvan, Arunachalam [Faculty of Allied Health Sciences, Chettinad Hospital & Research Institute, Kelambakkam, Tamilnadu 603 103 (India); Ganesan, Tharumeya Kuppusamy [Department of Chemistry, The American College, Madurai, Tamilnadu 625 002 (India); Viswanathan, Balasubramanian, E-mail: bvnathan@iitm.ac.in [National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India)

    2017-02-28

    Highlights: • On interaction with adsorbate CO{sub 2,} the adsorbent changes its configuration around the metal. • Electron transfer is faster in low coordinative environment of Cu. • CO formation is more favorable on Cu sites with even coordination number. • Cu at coordination number two has a over potential of −0.35 V. - Abstract: Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO{sub 2} to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO{sub 2} to CO at an applied potential of −0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO{sub 2} to various value added chemicals.

  8. Axial myopathy

    DEFF Research Database (Denmark)

    Witting, Nanna; Andersen, Linda K; Vissing, John

    2016-01-01

    musculature involvement in the majority of myopathies in which paraspinal musculature was examined. Even in diseases named after a certain pattern of non-axial muscle affection, such as facioscapulohumeral and limb girdle muscular dystrophies, affection of the axial musculature was often severe and early...

  9. Computer Calculations of Eddy-Current Power Loss in Rotating Titanium Wheels and Rims in Localized Axial Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Mayhall, D J; Stein, W; Gronberg, J B

    2006-05-15

    We have performed preliminary computer-based, transient, magnetostatic calculations of the eddy-current power loss in rotating titanium-alloy and aluminum wheels and wheel rims in the predominantly axially-directed, steady magnetic fields of two small, solenoidal coils. These calculations have been undertaken to assess the eddy-current power loss in various possible International Linear Collider (ILC) positron target wheels. They have also been done to validate the simulation code module against known results published in the literature. The commercially available software package used in these calculations is the Maxwell 3D, Version 10, Transient Module from the Ansoft Corporation.

  10. The influence on response of axial rotation of a six-group local-conductance probe in horizontal oil-water two-phase flow

    Science.gov (United States)

    Weihang, Kong; Lingfu, Kong; Lei, Li; Xingbin, Liu; Tao, Cui

    2017-06-01

    Water volume fraction is an important parameter of two-phase flow measurement, and it is an urgent task for accurate measurement in horizontal oil field development and optimization of oil production. The previous ring-shaped conductance water-cut meter cannot obtain the response values corresponding to the oil field water conductivity for oil-water two-phase flow in horizontal oil-producing wells characterized by low yield liquid, low velocity and high water cut. Hence, an inserted axisymmetric array structure sensor, i.e. a six-group local-conductance probe (SGLCP), is proposed in this paper. Firstly, the electric field distributions generated by the exciting electrodes of SGLCP are investigated by the finite element method (FEM), and the spatial sensitivity distributions of SGLCP are analyzed from the aspect of different separations between two electrodes and different axial rotation angles respectively. Secondly, the numerical simulation responses of SGLCP in horizontal segregated flow are calculated from the aspect of different water cut and heights of the water layer, respectively. Lastly, an SGLCP-based well logging instrument was developed, and experiments were carried out in a horizontal pipe with an inner diameter of 125 mm on the industrial-scale experimental multiphase flow setup in the Daqing Oilfield, China. In the experiments, the different oil-water two-phase flow, mineralization degree, temperature and pressure were tested. The results obtained from the simulation experiments and simulation well experiments demonstrate that the designed and developed SGLCP-based instrument still has a good response characteristic for measuring water conductivity under the different conditions mentioned above. The validity and reliability of obtaining the response values corresponding to the water conductivity through the designed and developed SGLCP-based instrument are verified by the experimental results. The significance of this work can provide an effective

  11. Limitaciones de la tomografia axial computada en la localizacion de quistes hidatidicos abdominales en pacientes con confirmacion inmunodiagnostica Limitations of computerized axial tomography in the localization of abdominal hydatid cysts in patients with immunodiagnostic confirmation

    Directory of Open Access Journals (Sweden)

    E. A. Guarnera

    1984-12-01

    Full Text Available Se describe el aporte de la prueba de doble disfusión arco 5 (DD5 al diagnóstico de la hidatidosis en dos pacientes con operaciones previas. En una de ellas, asintomática, la reacción positiva a los cinco años de su última intervención quirúrgica por hidatidosis, permitió diagnosticar la presencia de quistes cuya localización abdominal fue establecida por la tomografía axial computada (TAC. En el otro caso, sintomático, aunque operado de hidatidosis nueve años antes, la positividad a la DD5 confirmó la etiología de la enfermedad que se había sospechado por centellografía, TAC y su historia clínica. En ambos casos, sin embargo, se hallaron en el acto quirúrgico otros quistes abdominales cuyas imágenes no habían sido reveladas en los estudios a los que se las había sometido.The contribution of the arc 5 double diffusion test (DD5 to the diagnosis of hydatidosis in two patients with previous surgery for this parasitic infection is described. In one of the patients, who was asymptomatic, the diagnosis was established on the basis of a positive DD5 reaction five years after her last surgical intervention. The abdominal location of cysts was revealed by computerized axial tomography (CAT. The other patient had been operated on for hydatidosis nine years earlier and showed symptoms. Positivity to the DD5 test confirmed the etiology of the disease, which had been suspected on the basis of her clinical history and the findings of scintillographic and CAT studies. In both cases, however, other abdominal cysts were found at surgery whose images had not been revealed in the previous studies.

  12. Quasi-axially symmetric stellarators

    Science.gov (United States)

    Garabedian, Paul R.

    1998-01-01

    Confinement of a plasma for controlled thermonuclear fusion is studied numerically. Toroidal equilibria are considered, with an emphasis on the Modular Helias-like Heliac 2 (MHH2), which is a stellarator of low aspect ratio with just two field periods surrounded by 16 modular coils. The geometry is fully three-dimensional, but there is an axial symmetry of the magnetic structure that is calculated to give confinement competitive with that in circular tokamaks. Additional vertical and toroidal field coils, together with a current drive, provide the flexibility and the control of rotational transform necessary for a successful experiment. An MHH3 device with three field periods and comparable quasi-axial symmetry is presented, too, and because of reversed shear, its physical properties may be better. Variational analysis of equilibrium and stability is shown to give a more reliable prediction of performance for these stellarators than linearized or local theories that suffer from a failure of differentiability and convergence. PMID:9707544

  13. Axial Flow Conditioning Device for Mitigating Instabilities

    Science.gov (United States)

    Ahuja, Vineet (Inventor); Birkbeck, Roger M. (Inventor); Hosangadi, Ashvin (Inventor)

    2017-01-01

    A flow conditioning device for incrementally stepping down pressure within a piping system is presented. The invention includes an outer annular housing, a center element, and at least one intermediate annular element. The outer annular housing includes an inlet end attachable to an inlet pipe and an outlet end attachable to an outlet pipe. The outer annular housing and the intermediate annular element(s) are concentrically disposed about the center element. The intermediate annular element(s) separates an axial flow within the outer annular housing into at least two axial flow paths. Each axial flow path includes at least two annular extensions that alternately and locally direct the axial flow radially outward and inward or radially inward and outward thereby inducing a pressure loss or a pressure gradient within the axial flow. The pressure within the axial flow paths is lower than the pressure at the inlet end and greater than the vapor pressure for the axial flow. The invention minimizes fluidic instabilities, pressure pulses, vortex formation and shedding, and/or cavitation during pressure step down to yield a stabilized flow within a piping system.

  14. Axial Rod Coupling Design

    National Research Council Canada - National Science Library

    Smith, David R

    2003-01-01

    .... The axial rod and coupling has been designed to withstand external survival loads ( 8.3 kN (1,870 lb) for Ring 5), and to maintain its length to within 7 microns after disassembly and reassembly...

  15. Axial static mixer

    Science.gov (United States)

    Sandrock, H.E.

    1982-05-06

    Static axial mixing apparatus includes a plurality of channels, forming flow paths of different dimensions. The axial mixer includes a flow adjusting device for adjustable selective control of flow resistance of various flow paths in order to provide substantially identical flows through the various channels, thereby reducing nonuniform coating of interior surfaces of the channels. The flow adjusting device may include diaphragm valves, and may further include a pressure regulating system therefor.

  16. Computerised Axial Tomography (CAT)

    Science.gov (United States)

    1990-06-01

    Tumoral pathology Tumoral pathology provides one of the most valid applications of computerised axial tomography. With this technique, it is possible to... retroperitoneal cavity, while, in the pulmonary field, the results obtained are less decisive. Let us analyse, briefly, the research carried out with CT...the abscesses, are generally of lesser density with respect to the integral parenchyma; also, with abscesses the limits of the tumoral mass are less

  17. [Extra-axial tumors of the central nervous system].

    Science.gov (United States)

    Mühl-Benninghaus, R

    2017-09-01

    Extra-axial tumors are intracranial neoplasms but are not located within the brain parenchyma. The localization of intracranial neoplasms helps to narrow down the possible differential diagnoses and also plays a deciding role in the treatment strategy and the prognosis. For this reason exact localization of these lesions is extremely important. Extra-axial tumors are the most common neoplasms among adults. They can be divided in a broad spectrum of histopathological subgroups. The most common extra-axial tumors are meningiomas, which arise from the dura mater. In the vast majority of cases they are benign and slowly growing. Only a few rare subgroups show aggressive behavior.

  18. Critical Axial Load

    Directory of Open Access Journals (Sweden)

    Walt Wells

    2008-01-01

    Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.

  19. Study of the axial heat conduction in parallel flow microchannel heat exchanger

    Directory of Open Access Journals (Sweden)

    Mushtaq Ismael Hasan

    2014-07-01

    The results showed that, the axial heat conduction plays an important role in a parallel flow microchannel heat exchanger and the factors affecting the local and average axial heat conduction are; Reynolds number (Re, thermal conductivity ratio (Kr, hydraulic diameter (Dh, thickness of separating wall (ts and channel volume. Increasing of Re, Kr and ts leads to an increase in the axial heat conduction while increasing of Dh and channel volume leads to a decrease in the axial heat conduction.

  20. Dissipative Axial Inflation

    CERN Document Server

    Notari, Alessio

    2016-12-22

    We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\\frac{\\phi}{f_\\gamma} F \\tilde{F}$, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density $\\rho_R$, which which can lead to inflation without the need of a flat potential. We analyze the system, for momenta $k$ smaller than the cutoff $f_\\gamma$, including numerically the backreaction. We consider the evolution from a given static initial condition and explicitly show that, if $f_\\gamma$ is smaller than the field excursion $\\phi_0$ by about a factor of at least ${\\cal O} (20)$, there is a friction effect which turns on before that the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of...

  1. Parkinsonian axial signs in schizophrenia.

    Science.gov (United States)

    Morgante, Francesca; Barbui, Corrado; Tinazzi, Michele

    2017-03-01

    We have recently demonstrated evidence of nigro-striatal denervation, disease progression and response to levodopa in a subgroup of patients with schizophrenia who developed parkinsonism. In the present study, we investigated whether axial parkinsonian signs might be an early manifestation of parkinsonism in schizophrenia not necessarily related to chronic administration of antipsychotic drugs (AP) drugs. From a baseline cohort of 299 schizophrenic patients who did not satisfy the diagnostic criteria for parkinsonism (presence of at least two of the following appendicular signs: bradykinesia, tremor, rigidity), we identified a group of patients who manifested two out of three axial parkinsonian signs (abnormality of trunk posture, hypomimia and short-step gait). Accordingly, we obtained two sub-groups of patients with schizophrenia, with (Schiz-Axial, N = 26), and without parkinsonian axial signs (Schiz-NO-Axial, N = 273). Clinical and demographical variables were compared between groups. The motor section of the Unified Parkinson's disease rating scale (UPDRS) was employed to measure motor disability. Schiz-Axial patients were significantly older (p = 0.007) and had longer disease duration (p = 0.04) compared to Schiz-NO-Axial. The two groups did not differ for variables related to AP treatment. Total UPDRS motor score (p signs might be an early manifestation of parkinsonism in schizophrenia associated to older age and longer disease duration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Fluorescence axial nanotomography with plasmonics.

    Science.gov (United States)

    Cade, Nicholas I; Fruhwirth, Gilbert O; Krasavin, Alexey V; Ng, Tony; Richards, David

    2015-01-01

    We present a novel imaging technique with super-resolution axial sensitivity, exploiting the changes in fluorescence lifetime above a plasmonic substrate. Using conventional confocal fluorescence lifetime imaging, we show that it is possible to deliver down to 6 nm axial position sensitivity of fluorophores in whole biological cell imaging. We employ this technique to map the topography of the cellular membrane, and demonstrate its application in an investigation of receptor-mediated endocytosis in carcinoma cells.

  3. Axial structure of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner

    2002-01-01

    We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.

  4. Experimental Studies on Strength Behaviour of Notched Glass/Epoxy Laminated Composites under Uni-axial and Bi-axial Loading

    Science.gov (United States)

    Guptha, V. L. Jagannatha; Sharma, Ramesh S.

    2017-11-01

    The use of FRP composite materials in aerospace, aviation, marine, automotive and civil engineering industry has increased rapidly in recent years due to their high specific strength and stiffness properties. The structural members contrived from such composite materials are generally subjected to complex loading conditions and leads to multi-axial stress conditions at critical surface localities. Presence of notches, much required for joining process of composites, makes it further significant. The current practice of using uni-axial test data alone to validate proposed material models is inadequate leading to evaluation and consideration of bi-axial test data. In order to correlate the bi-axial strengths with the uni-axial strengths of GFRP composite laminates in the presence of a circular notch, bi-axial tests using four servo-hydraulic actuators with four load cells were carried out. To determine the in-plane strength parameters, bi-axial cruciform test specimen model was considered. Three different fibre orientations, namely, 0°, 45°, and 90° are considered with a central circular notch of 10 mm diameter in the present investigation. From the results obtained, it is observed that there is a reduction in strength of 5.36, 2.41 and 13.92% in 0°, 45°, and 90° fibre orientation, respectively, under bi-axial loading condition as compared to that of uni-axial loading in laminated composite.

  5. About "axial" and "radial" diffusivities.

    Science.gov (United States)

    Wheeler-Kingshott, Claudia A M; Cercignani, Mara

    2009-05-01

    This article presents the potential problems arising from the use of "axial" and "radial" diffusivities, derived from the eigenvalues of the diffusion tensor, and their interpretation in terms of the underlying biophysical properties, such as myelin and axonal density. Simulated and in vivo data are shown. The simulations demonstrate that a change in "radial" diffusivity can cause a fictitious change in "axial" diffusivity and vice versa in voxels characterized by crossing fibers. The in vivo data compare the direction of the principle eigenvector in four different subjects, two healthy and two affected by multiple sclerosis, and show that the angle, alpha, between the principal eigenvectors of corresponding voxels of registered datasets is greater than 45 degrees in areas of low anisotropy, severe pathology, and partial volume. Also, there are areas of white matter pathology where the "radial" diffusivity is 10% greater than that of the corresponding normal tissue and where the direction of the principal eigenvector is altered by more than 45 degrees compared to the healthy case. This should strongly discourage researchers from interpreting changes of the "axial" and "radial" diffusivities on the basis of the underlying tissue structure, unless accompanied by a thorough investigation of their mathematical and geometrical properties in each dataset studied. (c) 2009 Wiley-Liss, Inc.

  6. Aerodynamic modelling and optimization of axial fans

    Energy Technology Data Exchange (ETDEWEB)

    Noertoft Soerensen, Dan

    1998-01-01

    A numerically efficient mathematical model for the aerodynamics of low speed axial fans of the arbitrary vortex flow type has been developed. The model is based on a blade-element principle, whereby the rotor is divided into a number of annular stream tubes. For each of these stream tubes relations for velocity, pressure and radial position are derived from the conservation laws for mass, tangential momentum and energy. The equations are solved using the Newton-Raphson methods, and solutions converged to machine accuracy are found at small computing costs. The model has been validated against published measurements on various fan configurations, comprising two rotor-only fan stages, a counter-rotating fan unit and a stator-rotor stator stage. Comparisons of local and integrated properties show that the computed results agree well with the measurements. Optimizations have been performed to maximize the mean value of fan efficiency in a design interval of flow rates, thus designing a fan which operates well over a range of different flow conditions. The optimization scheme was used to investigate the dependence of maximum efficiency on 1: the number of blades, 2: the width of the design interval and 3: the hub radius. The degree of freedom in the choice of design variable and constraints, combined with the design interval concept, provides a valuable design-tool for axial fans. To further investigate the use of design optimization, a model for the vortex shedding noise from the trailing edge of the blades has been incorporated into the optimization scheme. The noise emission from the blades was minimized in a flow rate design point. Optimizations were performed to investigate the dependence of the noise on 1: the number of blades, 2: a constraint imposed on efficiency and 3: the hub radius. The investigations showed, that a significant reduction of noise could be achieved, at the expense of a small reduction in fan efficiency. (EG) 66 refs.

  7. Axial vector Z‧ and anomaly cancellation

    Science.gov (United States)

    Ismail, Ahmed; Keung, Wai-Yee; Tsao, Kuo-Hsing; Unwin, James

    2017-05-01

    Whilst the prospect of new Z‧ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that in a large class of models masses of these new states are expected to be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.

  8. Electric machines with axial magnetic flux

    Science.gov (United States)

    Nuca, I.; Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Turcanu, A.

    2018-01-01

    The paper contains information on the performance of axial machines compared to cylindrical ones. At the same time, various constructive schemes of synchronous electromechanical converters with permanent magnets and asynchronous with short-circuited rotor are presented. In the developed constructions, the aim is to maximize the usage of the material of the stator windings. The design elements of the axial machine magnetic system are presented. The FEMM application depicted the array of the magnetic field of an axial machine.

  9. Centrifugal and axial compressor control

    CERN Document Server

    McMillan, Gregory K

    2009-01-01

    Control engineers, mechanical engineers and mechanical technicians will learn how to select the proper control systems for axial and centrifugal compressors for proper throughput and surge control, with a particular emphasis on surge control. Readers will learn to understand the importance of transmitter speed, digital controller sample time, and control valve stroking time in helping to prevent surge. Engineers and technicians will find this book to be a highly valuable guide on compressor control schemes and the importance of mitigating costly and sometimes catastrophic surge problems. It can be used as a self-tutorial guide or in the classroom with the book's helpful end-of-chapter questions and exercises and sections for keeping notes.

  10. The Emergence of Axial Parts

    Directory of Open Access Journals (Sweden)

    Peter Svenonius

    2007-01-01

    Full Text Available Many languages have specialized locative words or morphemes translating roughly into words like ‘front,’ ‘back,’ ‘top,’ ‘bottom,’ ‘side,’ and so on. Often, these words are used instead of more specialized adpositions to express spatial meanings corresponding to ‘behind,’ ‘above,’ and so on. I argue, on the basis of a cross-linguistic survey of such expressions, that in many cases they motivate a syntactic category which is distinct from both N and P, which I call AxPart for ‘Axial Part’; I show how the category relates to the words which instantiate it, and how the meaning of the construction is derived from the combination of P[lace] elements, AxParts, and the lexical material which expresses them.

  11. Bone Disease in Axial Spondyloarthritis.

    Science.gov (United States)

    Van Mechelen, Margot; Gulino, Giulia Rossana; de Vlam, Kurt; Lories, Rik

    2017-10-31

    Axial spondyloarthritis is a chronic inflammatory skeletal disorder with an important burden of disease, affecting the spine and sacroiliac joints and typically presenting in young adults. Ankylosing spondylitis, diagnosed by the presence of structural changes to the skeleton, is the prototype of this disease group. Bone disease in axial spondyloarthritis is a complex phenomenon with the coexistence of bone loss and new bone formation, both contributing to the morbidity of the disease, in addition to pain caused by inflammation. The skeletal structural changes respectively lead to increased fracture risk and to permanent disability caused by ankylosis of the sacroiliac joints and the spine. The mechanism of this new bone formation leading to ankylosis is insufficiently known. The process appears to originate from entheses, specialized structures that provide a transition zone in which tendon and ligaments insert into the underlying bone. Growth factor signaling pathways such as bone morphogenetic proteins, Wnts, and Hedgehogs have been identified as molecular drivers of new bone formation, but the relationship between inflammation and activation of these pathways remains debated. Long-standing control of inflammation appears necessary to avoid ankylosis. Recent evidence and concepts suggest an important role for biomechanical factors in both the onset and progression of the disease. With regard to new bone formation, these processes can be understood as ectopic repair responses secondary to inflammation-induced bone loss and instability. In this review, we discuss the clinical implications of the skeletal changes as well as the underlying molecular mechanisms, the relation between inflammation and new bone formation, and the potential role of biomechanical stress.

  12. Health and imaging outcomes in axial spondyloarthritis

    NARCIS (Netherlands)

    Machado, P.M.

    2016-01-01

    This thesis focuses on the assessment and monitoring of health and imaging outcomes in axial spondyloarthritis (SpA) and the relationship between these outcomes. Four major contributions to the understanding and management of axial SpA were made: 1) the improvement and facilitation of the assessment

  13. Axial anomalies of Lifshitz fermions

    CERN Document Server

    Bakas, Ioannis

    2011-01-01

    We compute the axial anomaly of a Lifshitz fermion theory with anisotropic scaling z=3 which is minimally coupled to geometry in 3+1 space-time dimensions. We find that the result is identical to the relativistic case using path integral methods. An independent verification is provided by showing with spectral methods that the eta-invariant of the Dirac and Lifshitz fermion operators in three dimensions are equal. Thus, by the integrated form of the anomaly, the index of the Dirac operator still accounts for the possible breakdown of chiral symmetry in non-relativistic theories of gravity. We apply this framework to the recently constructed gravitational instanton backgrounds of Horava-Lifshitz theory and find that the index is non-zero provided that the space-time foliation admits leaves with harmonic spinors. Using Hitchin's construction of harmonic spinors on Berger spheres, we obtain explicit results for the index of the fermion operator on all such gravitational instanton backgrounds with SU(2)xU(1) isom...

  14. Axially Ligated Phthalocyanine Conductors with Magnetic Moments

    Directory of Open Access Journals (Sweden)

    Tamotsu Inabe

    2017-04-01

    Full Text Available This mini-review describes electrical conductivity, magnetic properties, and magnetotransport properties of one-dimensional partially oxidized salts composed of axially ligated phthalocyanines, TPP[M(Pc(CN2]2 (TPP = tetraphenylphosphonium, Pc = phthalocyaninato, with M of Fe (d5, S = 1/2 and Cr (d3, S = 3/2. These salts are isomorphous, and π–π interactions in the crystal, that becomes the origin of the charge carriers, are nearly the same. Both the Fe and Cr salts show carrier localization and charge disproportionation which is enhanced by the interaction between local magnetic moments and conduction π-electrons (π–d interaction. However, the magnetic properties are slightly different between them. M = Fe has been found to show unique anisotropic magnetic properties and antiferromagnetic short-range magnetic order between the d-spins. On the other hand, for M = Cr, its magnetic moment is isotropic. Temperature dependence of the magnetic susceptibility shows typical Curie–Weiss behavior with negative Weiss temperature, but the exchange interaction is complicated. Both M = Fe and M = Cr show large negative magnetoresistance, reflecting the difference in the anisotropy. The magnetoresistance ratio (MR is larger in the Fe system than in the Cr system in the low magnetic field range, but MR in the Cr system exceeds that in the Fe system when the magnetic field becomes higher than 15 T. We discuss the mechanism of the giant negative magnetoresistance with reference to the d–d, π–d, and π–π interactions.

  15. Axial Super-resolution Evanescent Wave Tomography

    CERN Document Server

    Pendharker, Sarang; Newman, Ward; Ogg, Stephen; Nazemifard, Neda; Jacob, Zubin

    2016-01-01

    Optical tomographic reconstruction of a 3D nanoscale specimen is hindered by the axial diffraction limit, which is 2-3 times worse than the focal plane resolution. We propose and experimentally demonstrate an axial super-resolution evanescent wave tomography (AxSET) method that enables the use of regular evanescent wave microscopes like Total Internal Reflection Fluorescence Microscope (TIRF) beyond surface imaging, and achieve tomographic reconstruction with axial super-resolution. Our proposed method based on Fourier reconstruction achieves axial super-resolution by extracting information from multiple sets of three-dimensional fluorescence images when the sample is illuminated by an evanescent wave. We propose a procedure to extract super-resolution features from the incremental penetration of an evanescent wave and support our theory by 1D (along the optical axis) and 3D simulations. We validate our claims by experimentally demonstrating tomographic reconstruction of microtubules in HeLa cells with an axi...

  16. High harmonic generation from axial chiral molecules.

    Science.gov (United States)

    Wang, Dian; Zhu, Xiaosong; Liu, Xi; Li, Liang; Zhang, Xiaofan; Lan, Pengfei; Lu, Peixiang

    2017-09-18

    Axial chiral molecules, whose stereogenic element is an axis rather than a chiral center, have attracted widespread interest due to their important application, such as asymmetric synthesis and chirality transfer. We investigate high harmonic generation from axial chiral molecules with bichromatic counterrotating circularly polarized laser fields. High harmonic generation from three typical molecules: (Sa)-3-chloropropa-1,2-dien-1-ol, propadiene, and (Ra)-2,3-pentadiene is simulated with time-dependent density-functional theory and strong field approximation. We found that harmonic spectra for 3D oriented axial chiral molecules exhibit obvious circular dichroism. However, the circular dichroism of High harmonic generation from an achiral molecule is much trivial. Moreover, the dichroism of high harmonic generation still exists when axial chiral molecules are 1D oriented,such as (Sa) -3-chloropropa-1,2-dien-1-ol. For a special form of axial chiral molecules with the formula abC=C=Cab (a, b are different substituents), like (Ra)-2,3-pentadiene, the dichroism discriminations disappear when the molecules are only in 1D orientation. The circular dichroism of high harmonic generation from axial chiral molecules is well explained by the trajectory analysis based on the semiclassical three-step mechanism.

  17. Physics based modeling of axial compressor stall

    Science.gov (United States)

    Zaki, Mina Adel

    2009-12-01

    Axial compressors are used in a wide variety of aerodynamic applications and are one of the most important components in aero-engines. However, the operability of compressors is limited at low-mass flow rates by fluid dynamic instabilities such as stall and surge. These instabilities can lead to engine failure and loss of engine power which can compromise the aircraft safety and reliability. Thus, a better understanding of how stall occurs and the causes behind its inception is extremely important. In the vicinity of the stall line, the flow field is inherently unsteady due to the interactions between adjacent rows of blades, formation of separation cells, and the viscous effects including shock-boundary layer interactions. Accurate modeling of these phenomena requires a proper set of stable and accurate boundary conditions at the rotor-stator interface that conserve mass, momentum, and energy, while eliminating false reflections. As a part of this research effort, an existing 3-D Navier-Stokes analysis for modeling single stage compressors has been modified to model multi-stage axial compressors and turbines. Several rotor-stator interface boundary conditions have been implemented. These conditions have been evaluated for the first stage (a stator and a rotor) of the two-stage fuel turbine on the space shuttle main engine (SSME). Their effectiveness in conserving global properties such as mass, momentum, and energy across the interface while yielding good performance predictions has been evaluated. While all the methods gave satisfactory results, a characteristic based approach and an unsteady sliding mesh approach are found to work best. Accurate modeling of the formation of stall cells requires the use of advanced turbulence models. As a part of this effort, a new advanced turbulence model called the Hybrid RANS/KES (HRKES) model has been developed and implemented. This model solves the Menter's k-o-SST model near walls and switches to the Kinetic Eddy

  18. Molecular Electronics at Metal/Semiconductor Junctions. Si Inversion by Sub-Nanometer Molecular Films

    NARCIS (Netherlands)

    Yaffe, O.; Scheres, L.M.W.; Reddy Puniredd, S.; Stein, N.; Biller, A.; Har Lavan, R.; Shpaisman, H.; Zuilhof, H.; Haick, H.; Cahen, D.; Vilan, A.

    2009-01-01

    Electronic transport across n-Si-alkyl monolayer/Hg junctions is, at reverse and low forward bias, independent of alkyl chain length from 18 down to 1 or 2 carbons! This and further recent results indicate that electron transport is minority, rather than majority carrier dominated, occurs via

  19. Sub-nanometer stable precision MEMS clamping mechanism maintaining clamp force unpowered for TEM application

    NARCIS (Netherlands)

    Brouwer, Dannis Michel; de Jong, B.R.; Soemers, Herman; van Dijk, Johannes

    2006-01-01

    A design is presented for a relatively large force (0.5 mN) high-precision MEMS clamping mechanism. The clamp is a part of a MEMS transmission electron microscope (TEM) sample manipulator, which needs to be fixed unpowered once positioned. The elastic deformation of the clamp suspension has been

  20. Imaging a pore network in a clay-rock at the sub-nanometer scale

    OpenAIRE

    Gaboreau, Stéphane; Pret², D; Tournassat, Christophe

    2017-01-01

    International audience; Mini-Symposium Description (2.22) Clayey rocks properties are the focus of an ever-increasing interest from the geoscience community. These fine-grained sedimentary rocks (mudstone, argillite, shalesetc.) are recognized as key-components for energy-related technologies, for which they could serve as isolation material (in radioactive waste disposal), caprocks (in CO 2 capture and storage systems), or as reservoir rocks for hydrocarbons (gas and oil shales) (Bourg, 2015...

  1. Supported sub-nanometer Ta oxide clusters as model catalysts for the selective epoxidation of cyclooctene

    KAUST Repository

    Zwaschka, Gregor

    2018-01-22

    The preparation of organic ligands-free, isolated tantalum oxide atoms (Ta1) and small clusters (Tan>1) on flat silicate supports was accomplished by ultra-high vacuum (UHV) techniques followed by oxidation in air. The resulting surface complexes were thoroughly characterized and tested as supported catalysts for the epoxidation of cycloalkenes. The observed catalytic performance highlights the potential of the applied method for the production of active catalysts and the study of well-defined, ligand-free metal oxide moieties.

  2. Optimization of residual heat removal pump axial thrust and axial bearing

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, F.

    1996-12-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.

  3. Positional cloning of the gene for pre-axial polydactyly

    Energy Technology Data Exchange (ETDEWEB)

    Heutink, P.; Breedveld, G.J.; Zguricas, J. [Erasmus Univ., Rotterdam (Netherlands)] [and others

    1994-09-01

    Pre-axial polydactyly can occur as an isolated anomaly, in association with other abnormalities of the hand or as a component of complex developmental disorders. We recently localized the gene for pre-axial polydactyly to the most distal part of chromosome 7q. Identification and characterization of the gene defect and studies of the expression pattern during embryonic development may help clarify questions about the role of this gene in other developmental processes than those in hands. A key element involved in the formation of the separate digits of the developing limb is the apical ectodermal ridge (AER). In the AER and in the adjacent mesoderm, homeobox genes as well as genes regulating programmed cell death, growth factors or receptors are expressed. Disruption of any of these genes might potentially interfere with normal differentiation. How these genes interact and which genes are involved in the formation of the five digits is still largely unknown. We have ascertained additional families and performed haplotype analysis to define the critical region. Currently, we are developing new STS polymorphic markers to narrow down this critical region. YAC and cosmid contigs are being developed. On the syntenic region of human 7q36, the mouse chromosome 5p, a mutation has been localized that resembles the human polydactyly phenotype. Hx is a candidate gene for the disease gene in the families studied. YACs from the critical regions of the human and mouse phenotypes are being used to identify conserved sequences. These sequences are used to isolate cDNAs which will be used for mutation analysis in human family material in order to isolate the responsible gene for pre-axial polydactyly. Our most recent results will be presented.

  4. Axial Vircator for Electronic Warfare Applications

    Directory of Open Access Journals (Sweden)

    L. Drazan

    2009-12-01

    Full Text Available This paper deals with a high power microwave generator with virtual cathode – vircator in axial release for electronic warfare applications. The classification of directed energy weapons microwave (DEWM is introduced together with basic block diagrams of a particular class of DEWM. In the paper, methods for designing vircator pulsed power supply, axial vircator structure, measurement methods and experimental results are presented. The vircator in electromagnetic ammunition is powered by magneto-cumulative generator and in weapons for defense of objects (WDO, it is powered by Marx generator. The possible applications of a vircator in the DEWM area are discussed.

  5. Axial pico turbine - construction and experimental research

    Science.gov (United States)

    Peczkis, G.; Goryca, Z.; Korczak, A.

    2017-08-01

    The paper concerns axial water turbine of power equal to 1 kW. The example of axial water turbine constructional calculations was provided, as well as turbine rotor construction with NACA profile blades. The laboratory test rig designed and built to perform measurements on pico turbine was described. The turbine drove three-phase electrical generator. On the basis of highest efficiency parameters, pico turbine basic characteristics were elaborated. The experimental research results indicated that pico turbine can achieve maximum efficiency close to the values of larger water turbines.

  6. Axial force measurement for esophageal function testing

    DEFF Research Database (Denmark)

    Gravesen, Flemming Holbæk; Funch-Jensen, Peter; Gregersen, Hans

    2009-01-01

    The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the "golden standard" for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze...... force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external...

  7. Aryabha~ and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 4. Aryabhata and Axial Rotation of Earth - Naksatra Dina (the Sidereal Day). Amartya Kumar Dutta. General Article Volume 11 Issue 4 April 2006 pp 56-74. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. Wave propagation in axially moving periodic strings

    DEFF Research Database (Denmark)

    Sorokin, Vladislav S.; Thomsen, Jon Juel

    2017-01-01

    The paper deals with analytically studying transverse waves propagation in an axially moving string with periodically modulated cross section. The structure effectively models various relevant technological systems, e.g. belts, thread lines, band saws, etc., and, in particular, roller chain drive...

  9. Co-axial, high energy gamma generator

    Science.gov (United States)

    Reijonen, Jani Petteri [Princeton, NJ; Gicquel, Frederic [Pennington, NJ

    2011-08-16

    A gamma ray generator includes an ion source in a first chamber. A second chamber is configured co-axially around the first chamber at a lower second pressure. Co-axially arranged plasma apertures separate the two chambers and provide for restricted passage of ions and gas from the first to the second chamber. The second chamber is formed by a puller electrode having at least one long channel aperture to draw ions from the first chamber when the puller electrode is subject to an appropriate applied potential. A plurality of electrodes rings in the third chamber in third pressure co-axially surround the puller electrode and have at least one channel corresponding to the at least one puller electrode aperture and plasma aperture. The electrode rings increase the energy of the ions to a selected energy in stages in passing between successive pairs of the electrodes by application of an accelerating voltage to the successive pairs of accelerator electrodes. A target disposed co-axially around the plurality of electrodes receives the beam of accelerated ions, producing gamma rays.

  10. Cystic lesions accompanying extra-axial tumours

    NARCIS (Netherlands)

    Lohle, PNM; Wurzer, HAL; Seelen, PJ; Kingma, LM; Go, KG

    We examined the mechanism of cyst formation in extra-axial tumours in the central nervous system (CNS). Cyst fluid, cerebrospinal fluid (CSF) and blood plasma were analysed in eight patients with nine peritumoral cysts: four with meningiomas, two with intracranial and two spinal intradural

  11. The design of axial shaftless pump

    Science.gov (United States)

    Schmirler, Michal; Netrebska, Hana

    The axial shaftless pump with a rotary casing has been proposed. The pump is unique in its small space requirements and the ability to draw a liquid with a high content of impurities and fibers. Modern motor with an external commutation was used to propel the pump rotor. The pump can be used for both pumping of liquids and marine propulsion.

  12. The design of axial shaftless pump

    Directory of Open Access Journals (Sweden)

    Schmirler Michal

    2017-01-01

    Full Text Available The axial shaftless pump with a rotary casing has been proposed. The pump is unique in its small space requirements and the ability to draw a liquid with a high content of impurities and fibers. Modern motor with an external commutation was used to propel the pump rotor. The pump can be used for both pumping of liquids and marine propulsion.

  13. VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR

    African Journals Online (AJOL)

    Dr Obe

    1984-09-01

    Sep 1, 1984 ... VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR by. L. A. Agu. Electrical Engineering Department. University of Nigeria, Nsukka. ABSTRACT. This paper presents the scheme for a very slow speed linear machine which uses conventional laminations and with which speeds of the same low.

  14. Localization of the cochlear amplifier in living sensitive ears.

    Directory of Open Access Journals (Sweden)

    Tianying Ren

    Full Text Available BACKGROUND: To detect soft sounds, the mammalian cochlea increases its sensitivity by amplifying incoming sounds up to one thousand times. Although the cochlear amplifier is thought to be a local cellular process at an area basal to the response peak on the spiral basilar membrane, its location has not been demonstrated experimentally. METHODOLOGY AND PRINCIPAL FINDINGS: Using a sensitive laser interferometer to measure sub-nanometer vibrations at two locations along the basilar membrane in sensitive gerbil cochleae, here we show that the cochlea can boost soft sound-induced vibrations as much as 50 dB/mm at an area proximal to the response peak on the basilar membrane. The observed amplification works maximally at low sound levels and at frequencies immediately below the peak-response frequency of the measured apical location. The amplification decreases more than 65 dB/mm as sound levels increases. CONCLUSIONS AND SIGNIFICANCE: We conclude that the cochlea amplifier resides at a small longitudinal region basal to the response peak in the sensitive cochlea. These data provides critical information for advancing our knowledge on cochlear mechanisms responsible for the remarkable hearing sensitivity, frequency selectivity and dynamic range.

  15. Ventajas de los motores de flujo axial

    Directory of Open Access Journals (Sweden)

    Alberto M Basanta Otero

    2011-03-01

    Full Text Available Es importante conocer sobre una familia de motores que a diferencia de los convencionales o tradicionales no presentanun flujo rotatorio radial, denominados motores de flujo axial. Dichos motores presentan altos valores de par motriz abajas velocidades, una alta eficiencia y alta densidad de potencia. Este trabajo constituye un breve análisis dealgunos motores de la referencia bibliográfica.  Is important to know about a family of motors that at difference whit the traditional, don't have a rotator radial flux,called, axial flux motors. These motors have high torque for low speed, high efficiency and high power density. Thiswork is a brief analysis of several motors of the bibliographic references.

  16. Induced axial and lateral color surface contributions.

    Science.gov (United States)

    Berner, Andrea; Nobis, Thomas; Gross, Herbert

    2017-05-01

    Induced aberrations in general are higher-order aberrations caused by ray perturbations of lower order, picked up in the preceding optical system. Therefore, in the case of color aberrations, induced influences can already be observed at the second order. They are generated by the preexisting first-order axial and lateral color. The analysis of relevant designs surface by surface to identify performance dominating lenses is a key method for understanding and optimizing those systems. Hence, in this paper a formula for the surface contribution of axial and lateral color including second-order terms is derived and discussed differentiating between intrinsic and induced parts. It is also shown how this can be used to deduce a thick-lens contribution of the second order. All of the approaches are based on the Seidel concept, which characterizes any arbitrary optical system only by the paraxial marginal and chief ray of the primary wavelength.

  17. Case Study of CPT-based Design Methods for Axial Capacity of Driven Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2012-01-01

    Today the design of onshore axially loaded driven piles in cohesionless soil is commonly made on basis of CPT-based methods because field investigations have shown strong correlation between the local shaft friction and the CPT cone resistance. However, the recommended design method for axially...... loaded offshore driven piles in cohesionless soil has until now been the β-method given in API. The API-method is based on the effective overburden pressure at the depth in question. Previous studies show deviations between full-scale load test measurements of the axial pile capacity and the predictions...... found by means of the API-method. Compared to the test measurements, the API-method under-estimates the capacity of short piles (piles in loose sand, and gives a shaft capacity less conservative for piles in tension than for piles in compression...

  18. Axial flux permanent magnet brushless machines

    CERN Document Server

    Gieras, Jacek F; Kamper, Maarten J

    2008-01-01

    Axial Flux Permanent Magnet (AFPM) brushless machines are modern electrical machines with a lot of advantages over their conventional counterparts. They are being increasingly used in consumer electronics, public life, instrumentation and automation system, clinical engineering, industrial electromechanical drives, automobile manufacturing industry, electric and hybrid electric vehicles, marine vessels and toys. They are also used in more electric aircrafts and many other applications on larger scale. New applications have also emerged in distributed generation systems (wind turbine generators

  19. Cyclotron axial ion-beam-buncher system

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, R.W.; Swenson, D.A.; Wangler, T.P.

    1982-02-11

    Adiabatic ion bunching is achieved in a cyclotron axial ion injection system through the incorporation of a radio frequency quadrupole system, which receives ions from an external ion source via an accelerate-decelerate system and a focusing einzel lens system, and which adiabatically bunches and then injects the ions into the median plane of a cyclotron via an electrostatic quadrupole system and an inflection mirror.

  20. Dynamic control of knee axial deformities

    OpenAIRE

    E. E. Malyshev; Pavlov, D. V.; S. V. Blinov

    2013-01-01

    The authors have evaluated the clinical examination of the patients with axial malalignments in the knee by the original method and device which was named varovalgometer. The measurements were conducted by tension of the cord through the spina iliaca anterior superior and the middle of the lower pole of patella. The deviation of the center of the ankle estimated by metal ruler which was positioned perpendicular to the lower leg axis on the level of the ankle joint line. The results of compari...

  1. Axial gravity, massless fermions and trace anomalies

    Science.gov (United States)

    Bonora, L.; Cvitan, M.; Prester, P. Dominis; Pereira, A. Duarte; Giaccari, S.; Štemberga, T.

    2017-08-01

    This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the theoretical background underlying the approach and complete the calculation of the anomaly. The reference is in particular to the difference between Weyl and massless Majorana fermions and to the possible contributions from tadpole and seagull terms in the Feynman diagram approach. A first, basic, result of this paper is that a more thorough treatment, taking account of such additional terms and using dimensional regularization, confirms the earlier result. The introduction of an axial symmetric tensor besides the usual gravitational metric is instrumental to a different derivation of the same result using Dirac fermions, which are coupled not only to the usual metric but also to the additional axial tensor. The action of Majorana and Weyl fermions can be obtained in two different limits of such a general configuration. The results obtained in this way confirm the previously obtained ones.

  2. Enriched axial anomaly in Weyl materials

    Science.gov (United States)

    Raines, Zachary M.; Galitski, Victor M.

    2017-10-01

    While quantum anomalies are often associated with the breaking of a classical symmetry in the quantum theory, their anomalous contributions to observables remain distinct and well defined even when the symmetry is broken from the outset. This paper explores such anomalous contributions to the current, originating from the axial anomaly in a Weyl semimetal, and in the presence of a generic Weyl node-mixing term. We find that apart from the familiar anomalous divergence of the axial current proportional to a product of electric and magnetic fields, there is another anomalous term proportional to a product of the electric field and the orientation of a spin-dependent node-mixing vector. We obtain this result both by a quantum field-theoretic analysis of an effective Weyl action and solving an explicit lattice model. The extended spin-mixing mass terms, and the enriched axial anomaly they entail, could arise as mean-field or proximity-induced order parameters in spin-density-wave phases in Weyl semimetals or be generated dynamically within a Floquet theory.

  3. Biomechanical properties of axially myopic cornea.

    Science.gov (United States)

    Altan, Cigdem; Demirel, Berna; Azman, Engin; Satana, Banu; Bozkurt, Ercüment; Demirok, Ahmet; Yilmaz, Omer Faruk

    2012-01-01

    To investigate biomechanical parameters of the cornea measured with ocular response analyzer (ORA) in myopic eyes with high axial length and the relationship between these parameters and axial length (AL). A total of 165 eyes of 165 consecutive patients were included. Eyes with AL greater than 26 mm were named group 1 and eyes with AL shorter than 26 mm were named group 2. Axial length and keratometric values were measured by intraocular lens (IOL) Master optical biometry. Metrics of corneal biomechanical properties, including corneal hysteresis (CH) and corneal resistance factor (CRF), were measured with the ORA. The ORA also determined the values of intraocular pressure (IOPg) and corneal compensated IOP (IOPcc). The mean age of total subjects was 43.0 ± 15.6 years. Eighty-three eyes were included in group 1; 82 eyes were included in group 2. The CH and CRF of group 1 were significantly lower than group 2. The IOPcc was significantly higher in group 1 than group 2. When group 1 and group 2 were combined for analysis, CH was negatively correlated with age. Both CH and CRF were significantly correlated with SE. However, CH and CRF were negatively correlated with AL. Also, there was significant correlation between AL and IOPcc (pbiomechanical properties of the cornea change with elongation of the eye and this may have an impact on IOP measurement.

  4. Dynamic control of knee axial deformities

    Directory of Open Access Journals (Sweden)

    E. E. Malyshev

    2013-01-01

    Full Text Available The authors have evaluated the clinical examination of the patients with axial malalignments in the knee by the original method and device which was named varovalgometer. The measurements were conducted by tension of the cord through the spina iliaca anterior superior and the middle of the lower pole of patella. The deviation of the center of the ankle estimated by metal ruler which was positioned perpendicular to the lower leg axis on the level of the ankle joint line. The results of comparison of our method and computer navigation in 53 patients during the TKA show no statistically significant varieties but they differ by average 5° of valgus in clinical examination in comparison with mechanical axis which was identified by computer navigation. The dynamic control of axial malalignment can be used in clinical practice for estimation of the results of treatment of pathology with axial deformities in the knee; for the control of reduction and secondary displacement of the fractures around the knee; for assessment of instability; in planning of correctional osteotomies and intraoperative control of deformity correction; for estimation of Q angle in subluxation and recurrent dislocation of patella; in planning of TKA; during the growth of child it allows to assess the progression of deformity.

  5. Axial gravity, massless fermions and trace anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Bonora, L. [International School for Advanced Studies (SISSA), Trieste (Italy); KEK, Tsukuba (Japan). KEK Theory Center; INFN, Sezione di Trieste (Italy); Cvitan, M.; Giaccari, S.; Stemberga, T. [Zagreb Univ. (Croatia). Dept. of Physics; Prester, P.D. [Rijeka Univ. (Croatia). Dept. of Physics; Pereira, A.D. [UERJ-Univ. Estadual do Rio de Janeiro (Brazil). Dept. de Fisica Teorica; UFF-Univ. Federal Fluminense, Niteroi (Brazil). Inst. de Fisica

    2017-08-15

    This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the theoretical background underlying the approach and complete the calculation of the anomaly. The reference is in particular to the difference between Weyl and massless Majorana fermions and to the possible contributions from tadpole and seagull terms in the Feynman diagram approach. A first, basic, result of this paper is that a more thorough treatment, taking account of such additional terms and using dimensional regularization, confirms the earlier result. The introduction of an axial symmetric tensor besides the usual gravitational metric is instrumental to a different derivation of the same result using Dirac fermions, which are coupled not only to the usual metric but also to the additional axial tensor. The action of Majorana and Weyl fermions can be obtained in two different limits of such a general configuration. The results obtained in this way confirm the previously obtained ones. (orig.)

  6. Interocular evaluation of axial length and retinal thickness in people with myopic anisometropia.

    Science.gov (United States)

    Jiang, Zipei; Shen, Meixiao; Xie, Ruozhong; Qu, Jia; Xue, Anquan; Lu, Fan

    2013-07-01

    To investigate the changes in axial length and retinal thickness and their relationships with myopia in highly myopic anisometropia. A total of 87 Chinese subjects (25.28±11.98 years, mean±SD) were divided into two groups: anisometropia (n=38) and nonanisometropia (n=49). All eyes were measured for axial length, refractive status, and macular thickness (optical coherence tomography). Ocular biometric results were compared between eyes of subgroups. Linear correlation between refractive error and other biometric results was performed. In the anisometropic group, the inner ring macula and part of the outer ring macula (nasal and inferior quadrants) in the higher myopic eyes were significantly thinner than in the fellow eyes (P≤0.007), but the foveal thickness (minimum and average) was similar (P≥0.050) between the two eyes. However, the minimum and average foveal thicknesses were found to be significantly thicker in the highly myopic eyes than those in the emmetropic to moderate myopic eyes (P≤0.016) in the nonanisometropic group. Among the eyes ranging from emmetropia to high myopia, the refractive error was negatively correlated to the axial length of the eye (Panisometropia, the higher myopic eye has a longer axial length but a thinner parafoveal region than its fellow eye. The axial growth in the development of high myopia seems to be centrally regulated; however, the changes in parafoveal thickness are likely manipulated by local mechanisms within the eye.

  7. Endoscopic Transoral Resection of an Axial Chordoma: A Case Report

    Directory of Open Access Journals (Sweden)

    Taran S

    2015-11-01

    Full Text Available Upper cervical chordoma (UCC is rare condition and poses unique challenges to surgeons. Even though transoral approach is commonly employed, a minimally invasive technique has not been established. We report a 44-year old Malay lady who presented with a 1 month history of insidious onset of progressive neck pain without neurological symptoms. She was diagnosed to have an axial (C2 chordoma. Intralesional resection of the tumour was performed transorally using the Destandau endoscopic system (Storz, Germany. Satisfactory intralesional excision of the tumour was achieved. She had a posterior fixation of C1-C4 prior to that. Her symptoms improved postoperatively and there were no complications noted. She underwent adjuvant radiotherapy to minimize local recurrence. Endoscopic excision of UCC via the transoral approach is a safe option as it provides an excellent magnified view and ease of resection while minimizing the operative morbidity.

  8. Axial mercury segregation in direct current operated low-pressure argon mercury gas discharges: Part I. Experimental

    Science.gov (United States)

    Gielen, John W. A. M.; de Groot, Simon; van der Mullen, Joost J. A. M.

    2004-07-01

    Due to cataphoresis, axial segregation of mercury will occur when the gas discharge of a fluorescent lamp is operated by means of a direct current. A consequence of this is a non-uniform axial luminance distribution along the lamp. To determine the degree of axial mercury segregation experimentally, axial luminance distributions have been measured which are converted into axial mercury vapour pressure distributions by an appropriate calibration method. The mercury segregation has been investigated for variations in lamp tube radius (3.6-4.8 mm), argon buffer gas pressure (200-600 Pa) and lamp current (100-250 mA) at mercury vapour pressures set at the anode in the range from 0.2 to 9.0 Pa. From the experiments it has been concluded that the mercury vapour pressure gradient at any axial position for a certain lamp tube diameter, argon pressure and lamp current depends on the local mercury vapour pressure. This observation is in contrast to assumptions made in earlier modelling publications in which one mercury vapour pressure gradient is used for all axial positions. By applying a full factorial design, an empirical relation of the mercury segregation is found for any set of parameters inside the investigated parameter ranges.

  9. Might axial myofascial properties and biomechanical mechanisms be relevant to ankylosing spondylitis and axial spondyloarthritis?

    Science.gov (United States)

    Masi, Alfonse T

    2014-01-01

    Ankylosing spondylitis and axial spondyloarthropathy have characteristic age- and sex-specific onset patterns, typical entheseal lesions, and marked heritability, but the integrative mechanisms causing the pathophysiological and structural alterations remain largely undefined. Myofascial tissues are integrated in the body into webs and networks which permit transmission of passive and active tensional forces that provide stabilizing support and help to control movements. Axial myofascial hypertonicity was hypothesized as a potential excessive polymorphic trait which could contribute to chronic biomechanical overloading and exaggerated stresses at entheseal sites. Such a mechanism may help to integrate many of the characteristic host, pathological, and structural features of ankylosing spondylitis and axial spondyloarthritis. Biomechanical stress and strain were recently documented to correlate with peripheral entheseal inflammation and new bone formation in a murine model of spondyloarthritis. Ankylosing spondylitis has traditionally been classified by the modified New York criteria, which require the presence of definite radiographic sacroiliac joint lesions. New classification criteria for axial spondyloarthritis now include patients who do not fulfill the modified New York criteria. The male-to-female sex ratios clearly differed between the two patient categories - 2:1 or 3:1 in ankylosing spondylitis and 1:1 in non-radiographic axial spondyloarthritis - and this suggests a spectral concept of disease and, among females, milder structural alterations. Magnetic resonance imaging of active and chronic lesions in ankylosing spondylitis and axial spondyloarthritis reveals complex patterns, usually interpreted as inflammatory reactions, but shows similarities to acute degenerative disc disease, which attributed to edema formation following mechanical stresses and micro-damage. A basic question is whether mechanically induced microinjury and immunologically mediated

  10. Intrinsic carpal ligaments on MR and multidetector CT arthrography: comparison of axial and axial oblique planes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ryan K.L.; Griffith, James F.; Ng, Alex W.H.; Law, Eric K.C. [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince Of Wales Hospital, Hong Kong (China); Tse, W.L.; Wong, Clara W.Y.; Ho, P.C. [The Chinese University of Hong Kong, Department of Orthopedics and Traumatology, Prince Of Wales Hospital, Hong Kong (China)

    2017-03-15

    To compare axial and oblique axial planes on MR arthrography (MRA) and multidetector CT arthrography (CTA) to evaluate dorsal and volar parts of scapholunate (SLIL) and lunotriquetral interosseous (LTIL) ligaments. Nine cadaveric wrists of five male subjects were studied. The visibility of dorsal and volar parts of the SLIL and LTIL was graded semi-quantitatively (good, intermediate, poor) on MRA and CTA. The presence of a ligament tear was determined on arthrosocopy and sensitivity, specificity and accuracy of tear detection were calculated. Oblique axial imaging was particularly useful for delineating dorsal and volar parts of the LTIL on MRA with overall 'good' visibility increased from 11 % to 78 %. The accuracy of MRA and CTA in revealing SLIL and LTIL tear was higher using the oblique axial plane. The overall accuracy for detecting SLIL tear on CTA improved from 94 % to 100 % and from 89 % to 94 % on MRA; the overall accuracy of detecting LTIL tear on CTA improved from 89 % to 100 % and from 72 % to 89 % on MRA Oblique axial imaging during CT and MR arthrography improves detection of tears in the dorsal and volar parts of both SLIL and LTIL. (orig.)

  11. Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

    Science.gov (United States)

    Koplow, Jeffrey P.

    2016-02-16

    Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.

  12. Iterative autofocusing strategy for axial distance error correction in ptychography

    Science.gov (United States)

    Dou, Jiantai; Gao, Zhishan; Ma, Jun; Yuan, Caojin; Yang, Zhongming; Wang, Lei

    2017-11-01

    The axial distance error can degrade the quality and resolution of the image reconstructed by ptychography. An iterative autofocusing method is proposed to correct the axial distance error. Based on the Fresnel integral theory, an axial distance error model is established to present the effect of the axial distance error on the recovered image. The information of the retrieved image is chosen to calculate the axial distance by autofocusing algorithm. The calculated distance is used to replace the axial distance and applied for the image reconstruction. When the calculated axial distance reaches the convergence, the distance can be accurately obtained that can be used to enhance the quality and resolution of the reconstructed image. Simulations and experiments have been conducted to verify the performance of the proposed method.

  13. Aerodynamics of Advanced Axial-Flow Turbomachinery.

    Science.gov (United States)

    1980-11-30

    cementing in place short segments of lb ga. (1.2 mm I.D.) hypodermic tubing in drillud holes carefully aligned normal to the sidewall profile at the...PRESSURE I REFERENCE SCANPREF I I SYSTEM 0YTE NECKED- PRF NEEDLE VALVE PE PRRSSUE TRANSDUCER AMPLIF IER] POSITIONER TEMPERATURES I STO BE READ I...Compressors. U.S. NASA SP-36. 1965. 23. Hearsey, R. M. A Revised Computer Program for Axial Compressor Design Volume 1: Theory , Descriptions and User’s

  14. Cervical Spine Axial Rotation Goniometer Design

    Directory of Open Access Journals (Sweden)

    Emin Ulaş Erdem

    2012-06-01

    Full Text Available To evaluate the cervical spine rotation movement is quiet harder than other joints. Configuration and arrangement of current goniometers and devices is not always practic in clinics and some methods are quiet expensive. The cervical axial rotation goniometer designed by the authors is consists of five pieces (head apparatus, chair, goniometric platform, eye pads and camera. With this goniometer design a detailed evaluation of cervical spine range of motion can be obtained. Besides, measurement of "joint position sense" which is recently has rising interest in researches can be made practically with this goniometer.

  15. Ankylosing Spondylitis versus Nonradiographic Axial Spondyloarthritis

    DEFF Research Database (Denmark)

    Glintborg, Bente; Sørensen, Inge J; Østergaard, Mikkel

    2017-01-01

    OBJECTIVE: To compare baseline disease activity and treatment effectiveness in biologic-naive patients with nonradiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) who initiate tumor necrosis factor inhibitor (TNFi) treatment and to study the role of potential confounders....../disease duration/TNFi-type/smoking/baseline disease activity) on TNFi adherence and response [e.g., Bath Ankylosing Spondylitis Activity Index (BASDAI) 50%/20 mm]. RESULTS: The study included 1250 TNFi-naive patients with axSpA (29% nr-axSpA, 50% AS, 21% lacked radiographs of sacroiliac joints). Patients...

  16. Aerodynamic Modelling and Optimization of Axial Fans

    DEFF Research Database (Denmark)

    Sørensen, Dan Nørtoft

    A numerically efficient mathematical model for the aerodynamics oflow speed axial fans of the arbitrary vortex flow type has been developed.The model is based on a blade-element principle, whereby therotor is divided into a number of annular streamtubes.For each of these streamtubes relations...... and integrated propertiesshow that the computed results agree well with the measurements.Integrating a rotor-only version of the aerodynamic modelwith an algorithm for numerical designoptimization, enables the finding of an optimum fan rotor.The angular velocity of the rotor, the hub radius and the spanwise...

  17. Axial tomography in live cell laser microscopy

    Science.gov (United States)

    Richter, Verena; Bruns, Sarah; Bruns, Thomas; Weber, Petra; Wagner, Michael; Cremer, Christoph; Schneckenburger, Herbert

    2017-09-01

    Single cell microscopy in a three-dimensional (3-D) environment is reported. Cells are grown in an agarose culture gel, located within microcapillaries and observed from different sides after adaptation of an innovative device for sample rotation. Thus, z-stacks can be recorded by confocal microscopy in different directions and used for illustration in 3-D. This gives additional information, since cells or organelles that appear superimposed in one direction, may be well resolved in another one. The method is tested and validated with single cells expressing a membrane or a mitochondrially associated green fluorescent protein, or cells accumulating fluorescent quantum dots. In addition, axial tomography supports measurements of cellular uptake and distribution of the anticancer drug doxorubicin in the nucleus (2 to 6 h after incubation) or the cytoplasm (24 h). This paper discusses that upon cell rotation an enhanced optical resolution in lateral direction compared to axial direction can be utilized to obtain an improved effective 3-D resolution, which represents an important step toward super-resolution microscopy of living cells.

  18. Primary aberration coefficients for axial gradient-index lenses

    Science.gov (United States)

    Bociort, Florian

    1999-08-01

    As for homogeneous lenses, for axial gradients the analysis of the Seidel and chromatic aberration coefficients can be very useful in lens design. However, at present few commercial optical design programs list the Seidel aberrations of GRIN lenses and none of them lists the chromatic aberrations. In order to facilitate the computer implementation of the chromatic aberrations of axial GRIN lenses a new mathematical derivation for the axial and lateral color coefficients is presented. Also, new qualitative insight into the properties of axial GRIN lenses is obtained by introducing the thin-lens approximation in the aberration expressions. Within the domain of validity of this approximation, the primary aberrations of an axial GRIN lens are equivalent to those of a pair of homogeneous aspherical lens in contact, having a common plane surface and having refractive indices and Abbe numbers equal to the corresponding axial GRIN values at the two end surfaces.

  19. Measuring Earth’s axial tilt with a telescope

    Science.gov (United States)

    Suat Isildak, R.; Asuman Küçüközer, H.; Isik, Hakan

    2017-05-01

    In this study, a method to measure the Earth’s axial tilt is attempted by using a telescope. As a principal instrument, telescopes in astronomy courses are mostly to verify the astronomical objects in sky and not to make sense of astronomical events such as seasonal changes which is explained by the Earth’s axial tilt. This study outlines telescopic measurements to calculate the axial tilt at winter solstice.

  20. Energy Dissipation in Sandwich Structures During Axial Compression

    DEFF Research Database (Denmark)

    Urban, Jesper

    2002-01-01

    The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full-scale structu......The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full...

  1. Inertial fusion by magnetically transmitted axial cumulation

    Energy Technology Data Exchange (ETDEWEB)

    Eliezer, S.; Martinez-Val, J.; Piera, M. [Institute of Nuclear Fusion, Madrid (Spain); Vorobeichik, I.; Henis, Z. [Soreq Nuclear Research Centre, (Israel); Piera, M. [ETSII, UNED, Madrid (Spain)

    2000-07-01

    An analytical and numerical study is presented on the physics of Z-pinch implosions including magnetic fields to transmit the kinetic energy from the imploding shell to an axially placed filament. The shell kinetic energy can be built-up along a long pinch phase and a fraction of this energy could be transmitted to the filament in a much shorter interaction phase. Although initial estimates are very positive for energy cumulation in the filament, a deeper analysis shows that compressibility effects dominate the space-time evolution of the filament, and the energy cumulation level remains moderate. The scheme could be used to trigger fusion ignition in a direct-drive scenario (without radiation hohlraums) but driver specifications to get it are very demanding. (authors)

  2. Composite Axial Flow Propulsor for Small Aircraft

    Directory of Open Access Journals (Sweden)

    R. Poul

    2005-01-01

    Full Text Available This work focuses on the design of an axial flow ducted fan driven by a reciprocating engine. The solution minimizes the turbulization of the flow around the aircraft. The fan has a rotor - stator configuration. Due to the need for low weight of the fan, a carbon/epoxy composite material was chosen for the blades and the driving shaft.The fan is designed for optimal isentropic efficiency and free vortex flow. A stress analysis of the rotor blade was performed using the Finite Element  Method. The skin of the blade is calculated as a laminate and the foam core as a solid. A static and dynamic analysis were made. The RTM technology is compared with other technologies and is described in detail. 

  3. Axial coding and the grounded theory controversy.

    Science.gov (United States)

    Kendall, J

    1999-12-01

    The purpose of this article is to describe the similarities and differences between two approaches to grounded theory research: grounded theory as espoused by Glaser and grounded theory as espoused by Strauss and Corbin. The focus of the article is the controversy surrounding the use of axial coding. The author proposes a resolution to the controversy by suggesting that one does not need to view either approach as right or wrong; rather, the qualitative and grounded theory researcher can choose an approach, and that choice is based on the goal of the researcher's study. Examples of both approaches, from the author's research study on the experiences of living in a family with a child with attention deficit hyperactivity disorder (ADHD), are provided.

  4. Axially symmetric static sources of gravitational field

    Science.gov (United States)

    Hernandez-Pastora, J. L.; Herrera, L.; Martin, J.

    2016-12-01

    A general procedure to find static and axially symmetric, interior solutions to the Einstein equations is presented. All the so obtained solutions, verify the energy conditions for a wide range of values of the parameters, and match smoothly to some exterior solution of the Weyl family, thereby representing globally regular models describing non-spherical sources of gravitational field. In the spherically symmetric limit, all our models converge to the well known incompressible perfect fluid solution. The key stone of our approach is based on an ansatz allowing to define the interior metric in terms of the exterior metric functions evaluated at the boundary source. Some particular sources are obtained, and the physical variables of the energy-momentum tensor are calculated explicitly, as well as the geometry of the source in terms of the relativistic multipole moments. The total mass of different configurations is also calculated, it is shown to be equal to the monopole of the exterior solution.

  5. The Axial Part Phrase in Japanese

    Directory of Open Access Journals (Sweden)

    Kaori Takamine

    2007-01-01

    Full Text Available In this paper, I investigate the categorial status of spatial terms in locative/directional expressions in Japanese. I will show that a certain class of spatial terms have a distinct categorial status from both regular postpositions and nouns. On one hand, syntactic diagnostics such as doubling, coordination by to, and co-occurrence with demonstratives indicate that these spatial terms belong to a nominal category rather than to a postpositional category. On the other hand, the fact that these spatial terms are modified by range modifiers indicates that they are more similar to regular postpositions than to nouns. On the basis of these diagnostics, I will argue that spatial terms in Japanese need to be assigned a new category Axial Part Phrase which is proposed by Svenonius 2006.

  6. [The cornea in high axial myopia].

    Science.gov (United States)

    Touzeau, O; Gaujoux, T; Sandali, O; Allouch, C; Laroche, L; Borderie, V

    2014-06-01

    To compare corneal characteristics of eyes with high myopia with those of eyes with no spherical ametropia using Orbscan and ultrasonic pachymetry. Orbscan and ultrasonic pachymetry values were prospectively recorded in a study group of 105 patients with high myopia (i.e., axial length greater than 26mm in both eyes) and in a control group of 105 patients with no spherical ametropia (absolute value of spherical equivalent less than 1.25D regardless of cylinder value). Astigmatism data were expressed by rectangular coordinates in a dioptric plane. Axis was decomposed in 2 components (WTR/ATR and oblique) which were analyzed by Cos2axis and Sin2axis trigonometric functions. Enantiomorphism (mirror-image symmetry) between fellow eyes was quantified by a Euclidean distance for the location of the thinnest point and by the difference (in absolute value) between 180° and the sum of both axes for astigmatism. In the study group, the mean axial length and subjective spherical equivalent were, respectively, 27.82±2.14mm (26.00 to 34.06) and -9.00±3.46D (-4.71 to -19.82). The mean corneal astigmatism was +0.92D×91.3° in the study group and +0.65D×89.3° in the control group. The mean corneal cylinder was higher in the study group (1.44D versus 0.91D; Pspherical equivalent (r=-0.86; Pspherical ametropia, except for toricity. While the posterior segment elongates, development of high myopia appears not to affect corneal characteristics. Corneal toricity may be associated with evolution toward high myopia by perturbing mechanisms of emmetropization. Copyright © 2014. Published by Elsevier Masson SAS.

  7. Axial T1ρ MRI as a diagnostic imaging modality to quantify proteoglycan concentration in degenerative disc disease.

    Science.gov (United States)

    Mulligan, Kyle R; Ferland, Catherine E; Gawri, Rahul; Borthakur, Arijitt; Haglund, Lisbet; Ouellet, Jean A

    2015-11-01

    The aim of the study was to investigate if axial T1ρ MR images had similar accuracy as established sagittal T1ρ MRI for the assessment of proteoglycan concentration and content in intervertebral degenerated discs (IDDs). T1ρ and T2-weighted MR images of 12 intervertebral discs (IVDs) from 3 harvested human lumbar spines (levels L1-L2 to L5-S1) were grouped across their degenerative grade (Pfirrmann scores) and analyzed using a 3T MRI scanner in the axial and sagittal views. Post-processing of axial T1ρ-weighted images was performed using a Wiener filter. Median axial T1ρ values for traced regions of interest (ROIs) on color maps were compared against ROIs in the corresponding location in the sagittal plane of each disc. Assessment of sulfated glycosaminoglycans (GAGs) content was also performed. Comparison of post Wiener filtered mid-axial T1ρ values in the NP with corresponding mid-sagittal values revealed no statistical difference (P > 0.05). Higher axial T1ρ and biochemically measured GAGs content corresponded to a lower Pfirrmann grading of the IVDs. A strong association between the T1ρ values and the GAG contents was observed (r = 0.85, P = 0.0002). The axial T1ρ methodology was validated against sagittal T1ρ providing an augmented spatial representation of IVD and can facilitate localization of focal degeneration within IVDs. T1ρ values provided a better granularity assessment of degenerative disc disease as it correlated with proteoglycan concentration. Thus, Wiener filtering is an effective tool for removing noise from T1ρ-weighted axial MR images.

  8. Fluoroscopic lumbar interlaminar epidural injections in managing chronic lumbar axial or discogenic pain

    Directory of Open Access Journals (Sweden)

    Manchikanti L

    2012-08-01

    Full Text Available Laxmaiah Manchikanti,1,2 Kimberly A Cash,1 Carla D McManus,1 Vidyasagar Pampati,1 Ramsin Benyamin3,41Pain Management Center of Paducah, Paducah, KY; 2University of Louisville, Louisville, KY; 3Millennium Pain Center, Bloomington, IL; 4University of Illinois, Urbana-Champaign, IL, USAAbstract: Among the multiple causes of chronic low back pain, axial and discogenic pain are common. Various modalities of treatments are utilized in managing discogenic and axial low back pain including epidural injections. However, there is a paucity of evidence regarding the effectiveness, indications, and medical necessity of any treatment modality utilized for managing axial or discogenic pain, including epidural injections. In an interventional pain management practice in the US, a randomized, double-blind, active control trial was conducted. The objective was to assess the effectiveness of lumbar interlaminar epidural injections of local anesthetic with or without steroids for managing chronic low back pain of discogenic origin. However, disc herniation, radiculitis, facet joint pain, or sacroiliac joint pain were excluded. Two groups of patients were studied, with 60 patients in each group receiving either local anesthetic only or local anesthetic mixed with non-particulate betamethasone. Primary outcome measures included the pain relief-assessed by numeric rating scale of pain and functional status assessed by the, Oswestry Disability Index, Secondary outcome measurements included employment status, and opioid intake. Significant improvement or success was defined as at least a 50% decrease in pain and disability. Significant improvement was seen in 77% of the patients in Group I and 67% of the patients in Group II. In the successful groups (those with at least 3 weeks of relief with the first two procedures, the improvement was 84% in Group I and 71% in Group II. For those with chronic function-limiting low back pain refractory to conservative management

  9. In Vivo Classification of Breast Masses Using Features Derived From Axial-Strain and Axial-Shear Images

    OpenAIRE

    Xu, Haiyan; Varghese, Tomy; Jiang, Jingfeng; Zagzebski, James A.

    2012-01-01

    Breast cancer is currently the second leading cause of cancer deaths in women. Early detection and accurate classification of suspicious masses as benign or malignant is important for arriving at an appropriate treatment plan. In this article, we present classification results for features extracted from ultrasound-based, axial-strain and axial-shear images of breast masses. The breast-mass stiffness contrast, size ratio, and a normalized axial-shear strain area feature are evaluated for the ...

  10. Workshop on Measurement Needs for Local-Structure Determination in Inorganic Materials.

    Science.gov (United States)

    Levin, Igor; Vanderah, Terrell

    2008-01-01

    The functional responses (e.g., dielectric, magnetic, catalytic, etc.) of many industrially-relevant materials are controlled by their local structure-a term that refers to the atomic arrangements on a scale ranging from atomic (sub-nanometer) to several nanometers. Thus, accurate knowledge of local structure is central to understanding the properties of nanostructured materials, thereby placing the problem of determining atomic positions on the nanoscale-the so-called "nanostructure problem"-at the center of modern materials development. Today, multiple experimental techniques exist for probing local atomic arrangements; nonetheless, finding accurate comprehensive, and robust structural solutions for the nanostructured materials still remains a formidable challenge because any one of these methods yields only a partial view of the local structure. The primary goal of this 2-day NIST-sponsored workshop was to bring together experts in the key experimental and theoretical areas relevant to local-structure determination to devise a strategy for the collaborative effort required to develop a comprehensive measurement solution on the local scale. The participants unanimously agreed that solving the nanostructure problem-an ultimate frontier in materials characterization-necessitates a coordinated interdisciplinary effort that transcends the existing capabilities of any single institution, including national laboratories, centers, and user facilities. The discussions converged on an institute dedicated to local structure determination as the most viable organizational platform for successfully addressing the nanostructure problem. The proposed "institute" would provide an intellectual infrastructure for local structure determination by (1) developing and maintaining relevant computer software integrated in an open-source global optimization framework (Fig. 2), (2) connecting industrial and academic users with experts in measurement techniques, (3) developing and

  11. 3D strain map of axially loaded mouse tibia: a numerical analysis validated by experimental measurements.

    Science.gov (United States)

    Stadelmann, Vincent A; Hocke, Jean; Verhelle, Jensen; Forster, Vincent; Merlini, Francesco; Terrier, Alexandre; Pioletti, Dominique P

    2009-02-01

    A combined experimental/numerical study was performed to calculate the 3D octahedral shear strain map in a mouse tibia loaded axially. This study is motivated by the fact that the bone remodelling analysis, in this in vivo mouse model should be performed at the zone of highest mechanical stimulus to maximise the measured effects. Accordingly, it is proposed that quantification of bone remodelling should be performed at the tibial crest and at the distal diaphysis. The numerical model could also be used to furnish a more subtle analysis as a precise correlation between local strain and local biological response can be obtained with the experimentally validated numerical model.

  12. Axially Symmetric Bianchi Type-I Bulk-Viscous Cosmological ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy; Volume 34; Issue 3. Axially Symmetric Bianchi ... The present study deals with spatially homogeneous and anisotropic axially symmetric Bianchi type-I cosmological model with time variable cosmological term in the presence of bulk viscous fluid. The Einstein's field ...

  13. Improved axial position detection in optical tweezers measurements

    DEFF Research Database (Denmark)

    Dreyer, Jakob Kisbye; Berg-Sørensen, Kirstine; Oddershede, Lene

    2004-01-01

    We investigate the axial position detection of a trapped microsphere in an optical trap by using a quadrant photodiode. By replacing the photodiode with a CCD camera, we obtain detailed information on the light scattered by the microsphere. The correlation of the interference pattern with the axial...

  14. Vector and axial vector mesons at finite temperature

    OpenAIRE

    mallik, S.; Sarkar, Sourav

    2002-01-01

    We consider the thermal correlation functions of vector and axial-vector currents and evaluate corrections to the vector and axial-vector meson pole terms to one loop in chiral perturbation theory. As expected, the pole positions do not shift to leading order in temperature. But the residues decrease with temperature.

  15. Test Setup for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test setup for testing axially static and cyclic loaded piles in sand is described in the following. The purpose for the tests is to examine the tensile capacity of axially loaded piles in dense fully saturated sand. The pile dimensions are chosen to resemble full scale dimension of piles used...... in offshore pile foundations today....

  16. Multimode interaction in axially excited cylindrical shells

    Directory of Open Access Journals (Sweden)

    Silva F. M. A.

    2014-01-01

    Full Text Available Cylindrical shells exhibit a dense frequency spectrum, especially near the lowest frequency range. In addition, due to the circumferential symmetry, frequencies occur in pairs. So, in the vicinity of the lowest natural frequencies, several equal or nearly equal frequencies may occur, leading to a complex dynamic behavior. So, the aim of the present work is to investigate the dynamic behavior and stability of cylindrical shells under axial forcing with multiple equal or nearly equal natural frequencies. The shell is modelled using the Donnell nonlinear shallow shell theory and the discretized equations of motion are obtained by applying the Galerkin method. For this, a modal solution that takes into account the modal interaction among the relevant modes and the influence of their companion modes (modes with rotational symmetry, which satisfies the boundary and continuity conditions of the shell, is derived. Special attention is given to the 1:1:1:1 internal resonance (four interacting modes. Solving numerically the governing equations of motion and using several tools of nonlinear dynamics, a detailed parametric analysis is conducted to clarify the influence of the internal resonances on the bifurcations, stability boundaries, nonlinear vibration modes and basins of attraction of the structure.

  17. Dynamics and statics of flexible axially symmetric shallow shells

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available In this work, we propose the method for the investigation of stochastic vibrations of deterministic mechanical systems represented by axially symmetric spherical shells. These structure members are widely used as sensitive elements of pressure measuring devices in various branches of measuring and control industry, machine design, and so forth. The proposed method can be easily extended for the investigation of shallow spherical shells, goffer-type membranes, and so on. The so-called charts of control parameters for a shell subjected to a transversal uniformly distributed and local harmonic loading force and resistance moment are constructed. The scenarios of the transition of vibration of shallow-type system into chaotic state are investigated with the use of the theory of differential equations and the theory of nonlinear dynamics. The method of the control of chaotic vibrations of flexible spherical shells subjected to a transversal harmonic load through a synchronized action of either harmonic resistance moment or force is proposed, illustrated, and discussed.

  18. Axial focusing of energy from a hypervelocity impact on earth

    Energy Technology Data Exchange (ETDEWEB)

    Boslough, M.B.; Chael, E.P.; Trucano, T.G.; Crawford, D.A.

    1994-12-01

    We have performed computational simulations to determine how energy from a large hypervelocity impact on the Earth`s surface would couple to its interior. Because of the first-order axial symmetry of both the impact energy source and the stress-wave velocity structure of the Earth, a disproportionate amount of energy is dissipated along the axis defined by the impact point and its antipode (point opposite the impact). For a symmetric and homogeneous Earth model, all the impact energy that is radiated as seismic waves into the Earth at a given takeoff angle (ray parameter), independent of azimuthal direction, is refocused (minus attenuation) on the axis of symmetry, regardless of the number of reflections and refractions it has experienced. Material on or near the axis of symmetry experiences more strain cycles with much greater amplitude than elsewhere, and therefore experiences more irreversible heating. The focusing is most intense in the upper mantle, within the asthenosphere, where seismic energy is most effectively converted to heat. For a sufficiently energetic impact, this mechanism might generate enough local heating to create an isostatic instability leading to uplift, possibly resulting in rifting, volcanism, or other rearrangement of the interior dynamics of the planet. These simulations demonstrate how hypervelocity impact energy can be transported to the Earth`s interior, supporting the possibility of a causal link between large impacts on Earth and major internally-driven geophysical processes.

  19. Local Foods, Local Places

    Science.gov (United States)

    The Local Foods, Local Places technical assistance program protects human health and the environment, spurs revitalization, increases access to healthy foods, and creates economic opportunities by promoting local foods.

  20. Análisis de la fuerza axial en un transportador de sinfín // Analysis of axial force in a screw conveyor.

    Directory of Open Access Journals (Sweden)

    F. Aguilar Parés

    1999-01-01

    Full Text Available Durante el movimiento de un material en un transportador de sinfín surge una fuerza en dirección axial que influye en laselección de uno de los cojinetes de apoyo del equipo. En el artículo aparecen algunas soluciones constructivas que tienen encuentan la fuerza axial. Por otro lado se establece la relación entre la fuerza axial y el empuje axial y se precisa de quiendepende el sentido del empuje axial. Por último se propone un modelo matemático que relaciona la fuerza axial con la potenciarequerida por el equipo.Palabras claves: Transportador de sinf in, fuerza axial , empuje axial ._________________________________________________________________________AbstractDuring the movement of material in a screw conveyor surge a force in axial direction that influence in the selection of one ofthe equipment support bearings. Some constructive solutions appear in the article for considering the axial force. In the otherhand it is established the relation between axial force and axial thurst and it is precised whose direction thurst axial depend of.Finally it is proposed a mathematic model that relates the axial force with the power required by the equipment.Key words: Screw conveyor, axial force, axial thurst .

  1. Axial elongation following prolonged near work in myopes and emmetropes.

    Science.gov (United States)

    Woodman, Emily C; Read, Scott A; Collins, Michael J; Hegarty, Katherine J; Priddle, Scott B; Smith, Josephine M; Perro, Judd V

    2011-05-01

    To investigate the influence of a period of sustained near work upon axial length in groups of emmetropes (EMM) and myopes. Forty young adult subjects (20 myopes and 20 emmetropes) were recruited for the study. Myopes were further classified as early onset (EOM), late onset (LOM), stable (SM) or progressing (PM) subgroups. Axial length was measured with the IOLMaster instrument before, immediately after and then again 10 min after a continuous 30 min near task of 5 D accommodation demand. Measures of distance objective refraction were also collected. Significant changes in axial length were observed immediately following the near task. EOM axial length elongated on average by 0.027±0.021 mm, LOM by 0.014±0.020 mm, EMM by 0.010±0.015 mm, PM by 0.031±0.022 mm and SM by 0.014±0.018 mm. At the conclusion of the 10 min regression period, axial length measures were not significantly different from baseline values. Axial elongation was observed following a prolonged near task. Both EOM and PM groups showed increases in axial length that were significantly greater than emmetropes.

  2. Impact of pupil diameter on axial growth in orthokeratology.

    Science.gov (United States)

    Chen, Zhi; Niu, Lingling; Xue, Feng; Qu, Xiaomei; Zhou, Zimei; Zhou, Xingtao; Chu, Renyuan

    2012-11-01

    To compare axial elongation between myopic orthokeratology (OK) contact lens and spectacle wearers, and to investigate the impact of pupil diameter on axial growth in myopic children after OK treatment. Fifty-two Chinese children aged 9 to 14 years were enrolled in this study, 27 for the OK group and 25 for the single vision spectacle lenses (SVL) group. Subjects in each group were further divided into two subcategories according to their baseline scotopic pupil diameters. Axial length (AL) was measured at baseline and at every 6-month visit through to 24 months. Linear mixed-effect model was used to determine myopia progression (AL changes from baseline). In this model, repeated visits were taken as within-subject effect, and treatment group as well as pupil size were taken as between-subject effects. The interaction of treatment group*pupil size was analyzed. Relationships between axial growth at 24 months and baseline pupil area were analyzed in both lens groups. Twenty-five subjects in the OK group and 22 subjects in the SVL group completed the 24-month study. AL increased significantly throughout the observed 24-month period (F = 32.09, p Pupil size significantly affected axial growth (F = 15.95, p pupil size on axial growth (F = 24.66, p pupil sizes than those with below average pupil sizes in the OK group (F = 25.04, p pupil size did not affect axial growth in the SVL group (F = 0.46, p = 0.50). Baseline scotopic pupil area was significantly correlated to axial growth in the OK group (r = 0.405, p pupil diameters facilitate the effect of OK to slow axial growth in myopia. We speculate that this is because of enhancement of the myopic shift in the peripheral retina.

  3. Identifying Axial Spondyloarthritis in Electronic Medical Records of US Veterans.

    Science.gov (United States)

    Walsh, Jessica A; Shao, Yijun; Leng, Jianwei; He, Tao; Teng, Chia-Chen; Redd, Doug; Treitler Zeng, Qing; Burningham, Zachary; Clegg, Daniel O; Sauer, Brian C

    2017-09-01

    Large database research in axial spondyloarthritis (SpA) is limited by a lack of methods for identifying most types of axial SpA. Our objective was to develop methods for identifying axial SpA concepts in the free text of documents from electronic medical records. Veterans with documents in the national Veterans Health Administration Corporate Data Warehouse between January 1, 2005 and June 30, 2015 were included. Methods were developed for exploring, selecting, and extracting meaningful terms that were likely to represent axial SpA concepts. With annotation, clinical experts reviewed sections of text containing the meaningful terms (snippets) and classified the snippets according to whether or not they represented the intended axial SpA concept. With natural language processing (NLP) tools, computers were trained to replicate the clinical experts' snippet classifications. Three axial SpA concepts were selected by clinical experts, including sacroiliitis, terms including the prefix spond*, and HLA-B27 positivity (HLA-B27+). With supervised machine learning on annotated snippets, NLP models were developed with accuracies of 91.1% for sacroiliitis, 93.5% for spond*, and 97.2% for HLA-B27+. With independent validation, the accuracies were 92.0% for sacroiliitis, 91.0% for spond*, and 99.0% for HLA-B27+. We developed feasible and accurate methods for identifying axial SpA concepts in the free text of clinical notes. Additional research is required to determine combinations of concepts that will accurately identify axial SpA phenotypes. These novel methods will facilitate previously impractical observational research in axial SpA and may be applied to research with other diseases. © 2016, American College of Rheumatology.

  4. Dispositivos de asistencia ventricular de tipo axial

    Directory of Open Access Journals (Sweden)

    Albert Miralles Cassina

    2009-04-01

    Full Text Available El uso de dispositivos de asistencia ventricular se ha ido extendiendo en las últimas décadas. La mejora de los resultados ha ido acompañada del diseño de nuevos aparatos más pequeños y eficientes como son las bombas de flujo axial. las características técnicas básicas de estos dispositivos se hallan en la generación de un flujo continuo unidireccional conseguido mediante sistemas de turbina que obtienen su alimentación de una fuente eléctrica. Las ventajas principales de estos dispositivos son: su facilidad de implantación por su tamaño reducido, su prolongada durabilidad gracias a su sencillo diseño y su eficiencia energética al utilizar energía eléctrica. Su utilidad se ha podido demostrar en diferentes indicaciones de asistencia circulatoria mecánica, como en el caso de puente al trasplante o dispositivo de recuperación miocárdica, si bien donde radica más interés es en su uso como sistemas de asistencia circulatoria mecánica definitiva. Existe una variedad de modelos de diversos diseños. Son dispositivos que permiten soporte normalmente univentricular izquierdo, que se implantan en el tórax con cánula de entrada a nivel ventricular y cánula de salida a nivel aórtico. En este artículo se efectúa una descripción de los principales sistemas disponibles en la actualidad, comentando las características técnicas, ventajas e inconvenientes y un resumen de la experiencia existente.

  5. The Design Method of Axial Flow Runners Focusing on Axial Flow Velocity Uniformization and Its Application to an Ultra-Small Axial Flow Hydraulic Turbine

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2016-01-01

    Full Text Available We proposed a portable and ultra-small axial flow hydraulic turbine that can generate electric power comparatively easily using the low head of open channels such as existing pipe conduits or small rivers. In addition, we proposed a simple design method for axial flow runners in combination with the conventional one-dimensional design method and the design method of axial flow velocity uniformization, with the support of three-dimensional flow analysis. Applying our design method to the runner of an ultra-small axial flow hydraulic turbine, the performance and internal flow of the designed runner were investigated using CFD analysis and experiment (performance test and PIV measurement. As a result, the runners designed with our design method were significantly improved in turbine efficiency compared to the original runner. Specifically, in the experiment, a new design of the runner achieved a turbine efficiency of 0.768. This reason was that the axial component of absolute velocity of the new design of the runner was relatively uniform at the runner outlet in comparison with that of the original runner, and as a result, the negative rotational flow was improved. Thus, the validity of our design method has been verified.

  6. Uniform Decay for Solutions of an Axially Moving Viscoelastic Beam

    Energy Technology Data Exchange (ETDEWEB)

    Kelleche, Abdelkarim, E-mail: kellecheabdelkarim@gmail.com [Université des Sciences et de la Technologie Houari Boumediene, Faculté des Mathématiques (Algeria); Tatar, Nasser-eddine, E-mail: tatarn@Kfupm.edu.sa [King Fahd University of Petroleum and Minerals, Department of Mathematics and Statistics (Saudi Arabia)

    2017-06-15

    The paper deals with an axially moving viscoelastic structure modeled as an Euler–Bernoulli beam. The aim is to suppress the transversal displacement (transversal vibrations) that occur during the axial motion of the beam. It is assumed that the beam is moving with a constant axial speed and it is subject to a nonlinear force at the right boundary. We prove that when the axial speed of the beam is smaller than a critical value, the dissipation produced by the viscoelastic material is sufficient to suppress the transversal vibrations. It is shown that the rate of decay of the energy depends on the kernel which arise in the viscoelastic term. We consider a general kernel and notice that solutions cannot decay faster than the kernel.

  7. Massive Axial Gauge in the Exact Renormalization Group Approach

    Science.gov (United States)

    Panza, P.; Soldati, R.

    The Exact Renormalization Group (ERG) approach to massive gauge theories in the axial gauge is studied and the smoothness of the massless limit is analysed for a formally gauge invariant quantity such as the Euclidean Wilson loop.

  8. Landforms along transverse faults parallel to axial zone of folded ...

    Indian Academy of Sciences (India)

    -4. Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun. Sub-Himalaya, India. Khayingshing Luirei∗. , S S Bhakuni and Sanjay S Negi. Wadia Institute of Himalayan Geology, Dehradun, India.

  9. Axial squeeze strengthen effect on rotary magneto-rheological damper

    Science.gov (United States)

    Dong, Xiaomin; Duan, Chi; Yu, Jianqiang

    2017-05-01

    Pressure is an important factor to influence the performance of an magneto-rheological (MR) apparatus. The effect of the axial squeeze strengthen effect on rotary MR damper is investigated theoretically and experimentally in this study. First, a theoretical analysis in a microscopic view is proposed. It indicates that a concentrated increment of iron particle content in the working gap results in the effect. Then, a pressure-controlled rotary MR damper with the axial squeeze strengthen effect is designed, manufactured and tested. The results show that the axial squeeze strengthen effect on rotary MR damper is remarkable for the damper with lower particle content in MR fluids. In addition, there is an optimal pressure to obtain the maximum axial squeeze strengthen effect on the rotary MR damper.

  10. Time Domain Terahertz Axial Computed Tomography Non Destructive Evaluation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to demonstrate key elements of feasibility for a high speed automated time domain terahertz computed axial tomography (TD-THz CT) non destructive...

  11. Effect of axial heat flux distribution on CHF

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol

    2000-10-01

    Previous investigations for the effect of axial heat flux distributions on CHF and the prediction methods are reviewed and summarized. A total of 856 CHF data in a tube with a non-uniform axial heat flux distribution has been compiled from the articles and analyzed using the 1995 Groeneveld look-up table. The results showed that two representative correction factors, K5 of the look-up table and Tongs F factor, can be applied to describe the axial heat flux distribution effect on CHF. However, they overpredict slightly the measured CHF, depending on the quality and flux peak shape. Hence, a corrected K5 factor, which accounts for the axial heat flux distribution effect is suggested to correct these trends. It predicted the CHF power for the compiled data with an average error of 1.5% and a standard deviation of 10.3%, and also provides a reasonable prediction of CHF locations.

  12. Time Domain Terahertz Axial Computed Tomography Non Destructive Evaluation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase 2 project, we propose to develop, construct, and deliver to NASA a computed axial tomography time-domain terahertz (CT TD-THz) non destructive...

  13. AXIAL CHEMICAL HETEROGENEITY OF CONTINUOUSLY CASTED STEEL INGOTS

    Directory of Open Access Journals (Sweden)

    Ju. A. Samojlovich

    2005-01-01

    Full Text Available The results of theoretical description of the process of the axial chemical heterogeneity formation in continuously cast slug taking into account heat, diffusion and hydrodynamic phenomenon in two-phase zone of hardening steel are given.

  14. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    Axial Torsion of Gangrenous Meckel's Diverticulum Causing. Small Bowel Obstruction. K. Sasikumar, Ravinder Naik Noonavath, G. S. Sreenath, Nanda Kishore Maroju. INTRODUCTION. Meckel's diverticulum (MD) is a commonly encountered congenital anomaly of the small intestine. Autopsy studies estimate overall.

  15. Testing of Axially Loaded Bucket Foundation with Applied Overburden Pressure

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina; Ibsen, Lars Bo; Nielsen, Benjaminn Nordahl

    This report analyses laboratory testing data performed with a bucket foundation model subjected to axial loading. The examinations were conducted at the Geotechnical laboratory of Aalborg University. The report aims at showing and discussing the results of the static and cyclic axial loading tests...... on the bucket foundation model. Finally, a cyclic loading interaction diagram is given that can be applied for a full-scale bucket foundation design....

  16. The research on flow pulsation characteristics of axial piston pump

    Science.gov (United States)

    Wang, Bingchao; Wang, Yulin

    2017-01-01

    The flow pulsation is an important factor influencing the axial piston pump performance. In this paper we implement modeling and simulation of the axial piston pump with AMESim software to explore the flow pulsation characteristics under various factors . Theory analysis shows the loading pressure, angular speed, piston numbers and the accumulator impose evident influence on the flow pulsation characteristics. This simulation and analysis can be used for reducing the flow pulsation rate via properly setting the related factors.

  17. Axial myopia in computed and magnetic resonance tomography

    Energy Technology Data Exchange (ETDEWEB)

    Beyer-Enke, S.A.; Goerich, J.; Gamroth, A.

    1987-08-01

    The case of a 44-year old woman suffering from amblyopia on the left eye with unilateral proptosis caused by axial (progressive) myopia is presented. The clinical and radiological findings were discussed in reference to the literature. The diagnosis was established by ruling out neoplastic, inflammatory or endocrine causes for the exophtalmos. CT and MR scans revealed an enlarged left globe without evidence of orbital masses. The findings were regarded as typical for the diagnosis at axial myopia.

  18. Design and Test of a Transonic Axial Splittered Rotor

    Science.gov (United States)

    2015-06-15

    AXIAL SPLITTERED ROTOR A new design procedure was developed that uses commercial-off-the- shelf software (MATLAB, SolidWorks, and ANSYS-CFX) for the...TRANSONIC AXIAL SPLITTERED ROTOR Report Title A new design procedure was developed that uses commercial-off-the- shelf software (MATLAB, SolidWorks, and... placement , and performance benefits. In particular, it was determined that moving the splitter blade forward in the passage between the main blades

  19. Goldenhar syndrome with unusual association of pre-axial polydactyly.

    Science.gov (United States)

    Mishra, Deepak; Sinha, Bibhuti P; Kumar, Rakesh

    2009-01-01

    Goldenhar syndrome is a multiorgan involvement affecting mainly the eyes, auricle, and oral cavity. METHOD. Case report. A 7-month-old boy presenting with features of Goldenhar syndrome had ocular and auricular manifestations. There were no vertebral anomalies, but he had the unusual association of pre-axial polydactyly, which is not reported in the literature. Pre-axial polydactyly should also be considered as an association of Goldenhar syndrome.

  20. Study on axial strength of a channel-shaped pultruded GFRP member

    Science.gov (United States)

    Matsumoto, Yukihiro; Satake, Chito; Nisida, Kenji

    2017-10-01

    Fiber reinforced polymers (FRP) are widely used in vehicle and aerospace applications because of their lightweight and high-strength characteristics. Additionally, FRPs are increasingly applied to building structures. However, the elastic modulus of glass fiber reinforced polymers (GFRPs) is lower than that of steel. Hence, the evaluating the buckling strength of GFRP members for design purpose is necessary. The buckling strength is determined by Euler buckling mode as well as local buckling. In this study investigated the compressive strength of GFRP members subjected to axial compression through experiments and theoretical calculations. The adopted GFRP member was a channel-shaped GFRP, which was molded via pultrusion, at various lengths. Although, the mechanical properties as longitudinal elastic modulus and fiber volume fraction and strength of GFRP members subjected, to axial can be easily evaluated, evaluating transverse elastic modulus and shear modulus in typical material tests is difficult in standard section. Therefore the composite law was used in this study. As a result, we confirmed that the axial strength of a GFRP member could be calculated by a theoretical evaluation method utilizing longitudinal elastic modulus and fiber volume fraction.

  1. Reactive control of subsonic axial fan noise in a duct.

    Science.gov (United States)

    Liu, Y; Choy, Y S; Huang, L; Cheng, L

    2014-10-01

    Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical.

  2. Axial design of nuclear fuel using path relinking; Diseno axial de combustible nuclear utilizando path relinking

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, A.; Torres, M.; Ortiz, J. J.; Perusquia, R.; Hernandez, J. L.; Montes, J. L. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: jacm@nuclear.inin.mx

    2008-07-01

    In the present work the preliminary results were obtained with the zoctli system whose purpose is the axial design of assembly of nuclear fuel under certain considerations. For the mentioned design well-know cells were already used and that they have been proven in diverse cycles of operation in the nuclear power plant of Laguna Verde. The design contemplates fuels assemblies of 10x10 and with 2 water channels. The assembly was distributed in 6 axial zones according to its structure. In order to take to end the optimization is was used the well-known technique like Path relinking and to find the group of previous solutions required by this technique uses the technical Taboo search. In order to work with Path relinking, 5 trajectories was taken in to account from a set of 5 previous solutions generated with theTaboo search, the update of the group of solutions is carried out in dynamic form. In the case of the Taboo search it was used a list of variable size, it was implement an aspiration approach, it was used the vector of frequencies and due to the cost of the evaluation of the objective function, only it was review 5% of the vicinity. For the objective function was considered the limit thermal, the axial profile of power, the effective multiplication factor and the margin of having turned off in cold. In order to prove the design system, it was used a balance cycle with a value of reference of 0.9928 for the effective multiplication factor that is equivalent to a produced energy of 10896 MWd/TU at the end of operation to full power. The designed assemblies were placed both in one of lots different from fresh assemblies on which it counts the referred cycle. At the end one a comparison with the results obtained with other techniques and under similar conditions is made. The results obtained until the moment show an appropriate performance of the system. It is possible to indicate that a small inconvenient is the amount of consumed resources of calculation during

  3. Orthophragminids with new axial thickening structures from the Bartonian of the Indian subcontinent

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, E.; Kumar Saraswati, P.; Hanif, M.; Ali, N.

    2016-07-01

    The ‘axial thickening’, a morphological character of certain Eocene orthophragminids refers to the thickening of the equatorial and/or lateral layers in axial directions forming radial external structures, namely the ribs. The occurrence of ribs is considered to be a diagnostic specific character of the orthophragminids in the periMediterranean region and Europe (western Tethys). In the Bartonian orthophragminids of the Indian subcontinent we observe a new type of axial thickening that we name ‘bulges’. The bulges are semi-rounded to rounded, localized structures on the test surface formed solely by the greater development of lateral chamberlets. These specimens, with trybliolepidine to umbilicolepidine type embryon configuration, co-occur with ribbed discocyclinids having completely different internal features. We also record another type of axial thickening of the lateral layers in notably small omphaloid tests that are characterized by a thick umbo, deeply depressed at the center such that the periphery of it forms a thick circular structure. The reported omphaloid specimens possess a small, semiisolepidine to nephrolepidine type embryon configuration and characteristic early chambers, not comparable to any known species in the Tethys. These specimens occasionally may have incomplete and/or irregular septula, reminiscent of certain Caribbean orthophragminids. The specimens with bulges, identified in two geographically distant regions of the Indian subcontinent, possibly represent endemic foraminiferal fauna confined to the IndoPakistan region. We introduce two new species, Discocyclina kutchensis sp. nov. (characterized by bulges) and ‘D’. sulaimanensis sp. nov. (characterized by circular structures in omphaloid tests). The status of both taxa in the Tethys is discussed. (Author)

  4. Internal combustion engine with axial double pistons. Verbrennungsmotor mit axial angeordneten Doppelkolben

    Energy Technology Data Exchange (ETDEWEB)

    Albersinger, G.

    1980-07-24

    The invention refers to the configuration of an internal combustion engine with axial double pistons. It is characterized by the fact that these double pistons work in a cylinder block divided into a suction side and a combustion side, where a so-called swashplate acts as the power transmission part between the piston and the drive shaft. Special constructional characteristics of the cylinder block divided into two are that the suction half and the combustion half are connected by a crankcase, which accommodates the swashplate, and that automatic inlet valves are situated in the cylinder head of the suction half and outlet valves actuated by the drive shaft are situated in the cylinder head on the combustion side. This construction of engine according to the invention has a very high efficiency. Further, there is a very favourable effect on the generation of exhaust gas and low value fuels can be used.

  5. Halden In-Reactor Test to Exhibit PWR Axial Offset Anomaly

    Energy Technology Data Exchange (ETDEWEB)

    P.Bennett, B. Beverskog, R.Suther

    2004-12-01

    Many PWRs have encountered the axial offset anomaly (AOA) since the early 1990s, and these experiences have been reported widely. AOA is a phenomenon associated with localized boron hideout in corrosion product deposits (crud) on fuel surfaces. Several mitigation approaches have been developed or are underway to either delay the onset of AOA or avoid it entirely. This study describes the first phase of an experimental program designed to investigate whether the use of enriched boric acid (EBA) in the reactor coolant can mitigate AOA.

  6. BUCKLING BEHAVIOUR OF SINGLE-WALLED CARBON NANOTUBES UNDER AXIAL LOADING

    Directory of Open Access Journals (Sweden)

    Grzegorz Litak

    2017-03-01

    Full Text Available We investigate a single walled Carbon Nanotube under an axially directed compressive line loading applied at both of its edges. The expected buckling behavior we study by application of a molecular computation approach. We formulate a global potential and search for its minimum to obtain the equilibrium configuration. Using besides the main parameter, which is the value of the loading, as second parameter the diameter of the tube, we are able to define the critical value of the diameter, for which we obtain the coincident case of local shell buckling.

  7. Musculoskeletal MRI findings of juvenile localized scleroderma

    Energy Technology Data Exchange (ETDEWEB)

    Eutsler, Eric P. [Nemours Children' s Health System/Alfred I. duPont Hospital for Children, Wilmington, DE (United States); Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Horton, Daniel B. [Nemours Children' s Health System/Alfred I. duPont Hospital for Children, Division of Rheumatology, Department of Pediatrics, Wilmington, DE (United States); Rutgers Robert Wood Johnson Medical School, Department of Pediatrics, New Brunswick, NJ (United States); Epelman, Monica [Nemours Children' s Health System/Nemours Children' s Hospital, Department of Medical Imaging, Orlando, FL (United States); Finkel, Terri [Nemours Children' s Health System/Nemours Children' s Hospital, Department of Pediatrics, Orlando, FL (United States); Averill, Lauren W. [Nemours Children' s Health System/Alfred I. duPont Hospital for Children, Wilmington, DE (United States)

    2017-04-15

    Juvenile localized scleroderma comprises a group of autoimmune conditions often characterized clinically by an area of skin hardening. In addition to superficial changes in the skin and subcutaneous tissues, juvenile localized scleroderma may involve the deep soft tissues, bones and joints, possibly resulting in functional impairment and pain in addition to cosmetic changes. There is literature documenting the spectrum of findings for deep involvement of localized scleroderma (fascia, muscles, tendons, bones and joints) in adults, but there is limited literature for the condition in children. We aimed to document the spectrum of musculoskeletal magnetic resonance imaging (MRI) findings of both superficial and deep juvenile localized scleroderma involvement in children and to evaluate the utility of various MRI sequences for detecting those findings. Two radiologists retrospectively evaluated 20 MRI studies of the extremities in 14 children with juvenile localized scleroderma. Each imaging sequence was also given a subjective score of 0 (not useful), 1 (somewhat useful) or 2 (most useful for detecting the findings). Deep tissue involvement was detected in 65% of the imaged extremities. Fascial thickening and enhancement were seen in 50% of imaged extremities. Axial T1, axial T1 fat-suppressed (FS) contrast-enhanced and axial fluid-sensitive sequences were rated most useful. Fascial thickening and enhancement were the most commonly encountered deep tissue findings in extremity MRIs of children with juvenile localized scleroderma. Because abnormalities of the skin, subcutaneous tissues and fascia tend to run longitudinally in an affected limb, axial T1, axial fluid-sensitive and axial T1-FS contrast-enhanced sequences should be included in the imaging protocol. (orig.)

  8. Atlanto-axial malformation and instability in dogs with pituitary dwarfism due to an LHX3 mutation.

    Science.gov (United States)

    Voorbij, A M W Y; Meij, B P; van Bruggen, L W L; Grinwis, G C M; Stassen, Q E M; Kooistra, H S

    2015-01-01

    Canine pituitary dwarfism or combined pituitary hormone deficiency (CPHD) in shepherd dogs is associated with an LHX3 mutation and can lead to a wide range of clinical manifestations. Some dogs with CPHD have neurological signs that are localized to the cervical spine. In human CPHD, caused by an LHX3 mutation, anatomical abnormalities in the atlanto-axial (C1-C2) joint have been described. To evaluate the presence of atlanto-axial malformations in dogs with pituitary dwarfism associated with an LHX3 mutation and to investigate the degree of similarity between the atlanto-axial anomalies found in canine and human CPHD patients with an LHX3 mutation. Three client-owned Czechoslovakian wolfdogs and 1 client-owned German shepherd dog, previously diagnosed with pituitary dwarfism caused by an LHX3 mutation, with neurological signs indicating a cervical spinal disorder. Radiography, computed tomography, and magnetic resonance imaging of the cranial neck and skull, necropsy, and histology. Diagnostic imaging identified abnormal positioning of the dens axis and incomplete ossification of the suture lines between the ossification centers of the atlas with concurrent atlanto-axial instability and dynamic compression of the spinal cord by the dens axis. The malformations and aberrant motion at C1-C2 were confirmed at necropsy and histology. The atlanto-axial abnormalities of the dwarf dogs resemble those encountered in human CPHD patients with an LHX3 mutation. These findings suggest an association between the LHX3 mutation in dogs with CPHD and atlanto-axial malformations. Consequently, pituitary dwarfs should be monitored closely for neurological signs. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of American College of Veterinary Internal Medicine.

  9. Axial Lengths in Children with Recessive Cornea Plana.

    Science.gov (United States)

    Al Hazimi, Amro; Khan, Arif O

    2015-06-01

    While flat keratometry contributes to the hyperopia and associated refractive accommodative esotropia that is part of recessive cornea plana, whether or not axial lengths are abnormally short in the disease is unclear. In this study we assess this possibility. Prospective (2010-2012) axial length measurement (IOLmaster; Carl Zeiss, Oberkochen, Germany) of affected right eyes and comparison to right eyes with refractive accommodative esotropia only. Keratometry and refraction were also performed. For eight affected right eyes (age 10-12 years; seven families) axial length ranged from 21.46-24.80 mm (mean 23.34). Best corrected visual acuity ranged from 20/25 to 20/50, keratometry from 25.33-39.80 diopters (D) [mean 31.80], and refraction from +2.00 to +14.00 D (mean +7.22). For 50 control right eyes (age 4-12 years), axial length ranged from 19.87-23.66 mm (mean 21.6). Best-corrected visual acuity was 20/25 or better, keratometry ranged from 39.81-46.25 D (mean 42.42), and refraction from +2.25 to +8.00 D (mean 4.71). Axial lengths were longer in the affected group (2-tailed unpaired t-test p value 0.000005) despite greater hyperopia (2-tailed unpaired t-test p value 0.001). Despite greater hyperopia, axial lengths were longer in eyes with recessive cornea plana, evidence that axial lengths are not shortened by the disease. Keratometry in children with cornea plana was below the range of controls and was the major factor underlying the phenotype's hyperopia.

  10. Radiographic assessment of thoracolumbar fractures based on axial zones.

    Science.gov (United States)

    Baaj, Ali A; Gantwerker, Brian R; Theodore, Nicholas; Uribe, Juan S; Vale, Fernando L; Crawford, Neil R; Sonntag, Volker K H

    2014-04-01

    Retrospective study of computed tomography imaging of patients with thoracolumbar (TL) fractures. To propose an axial model of spinal fractures based on the osteoligamentous continuity of the TL spinal segments in the axial plane and to determine the correlation between the 3-column theory and the proposed axial zone model. Predicting spinal instability of TL fractures is based on several radiologic and clinical parameters. Efforts to refine fracture classification schemes to better predict instability continue. Computed tomography scans of 229 consecutive patients who presented with TL fractures between March 2005 and April 2007 were reviewed. TL fractures were classified according to both the Denis 3-column theory and the proposed axial zone model. The incidence of column and axial zone injuries was determined. On the basis of these results, a treatment algorithm was developed. Zone disruption in surgical fractures was distributed as follows: 24 (96%) involved zone A, 25 (100%) involved zone B, 17 (68%) involved zone C, and 15 (60%) involved zone D. All surgical fractures involved 2 or more zones. Zone B was involved in all surgical fractures. The likelihood of surgical intervention increased as the number of zones increased, especially if the injury was a 2-column or 3-column injury. The current 3-column theory of spinal stability does not account for the axial component of an injury. Application of our proposed "axial zone model" may enhance the ability to predict stability, depending not only on the number of columns, but also on the number of zones involved in the injuries. Further clinical and biomechanical studies are warranted to validate this model.

  11. Local atomic structure in iron copper binary alloys: An extended X-ray absorption fine structure study

    Energy Technology Data Exchange (ETDEWEB)

    Kuri, G. [LWV, NES, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)]. E-mail: goutam.kuri@psi.ch; Degueldre, C. [LWV, NES, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Bertsch, J. [LWV, NES, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Rothe, J. [INE, Forschungszentrum Karlsruhe, 76344 Karlsruhe (Germany)

    2007-05-31

    Understanding the clustering process and the evolution of the precipitate structure of copper in Fe-Cu system is an important step in the description of material hardening and the embrittlement process normally observed under irradiation conditions. In this work, an extended X-ray absorption fine structure (EXAFS) spectroscopy characterization of Fe-0.3 wt%Cu and Fe-1.0 wt%Cu binary model alloys has been performed in order to investigate the local structure around Cu and Fe atoms in the matrix. The effect of thermal ageing was studied on one Fe-Cu specimen containing 1.0 wt% Cu annealed at 775 K for a duration of 1 h. The near-neighbour environment of Cu and Fe was examined by determining the best-fit structural parameters after curve fitting to the first-few-shells EXAFS functions. The results provide an indication of the formation of sub-nanometer-size Cu clusters in Fe matrix for the specimens examined. The average structural parameters estimated from the EXAFS data are presented and discussed.

  12. The window of opportunity: a relevant concept for axial spondyloarthritis.

    Science.gov (United States)

    Robinson, Philip C; Brown, Matthew A

    2014-01-01

    The window of opportunity is a concept critical to rheumatoid arthritis treatment. Early treatment changes the outcome of rheumatoid arthritis treatment, in that response rates are higher with earlier disease-modifying anti-rheumatic drug treatment and damage is substantially reduced. Axial spondyloarthritis is an inflammatory axial disease encompassing both nonradiographic axial spondyloarthritis and established ankylosing spondylitis. In axial spondyloarthritis, studies of magnetic resonance imaging as well as tumor necrosis factor inhibitor treatment and withdrawal studies all suggest that early effective suppression of inflammation has the potential to reduce radiographic damage. This potential would suggest that the concept of a window of opportunity is relevant not only to rheumatoid arthritis but also to axial spondyloarthritis. The challenge now remains to identify high-risk patients early and to commence treatment without delay. Developments in risk stratification include new classification criteria, identification of clinical risk factors, biomarkers, genetic associations, potential antibody associations and an ankylosing spondylitis-specific microbiome signature. Further research needs to focus on the evidence for early intervention and the early identification of high-risk individuals.

  13. Development and Testing of an Axial Halbach Magnetic Bearing

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2006-01-01

    The NASA Glenn Research Center has developed and tested a revolutionary Axial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic thrust bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Axial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Axial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical systems, computer memory systems, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Axial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.

  14. Axial Instability of Coating Flow in a Horizontal Rotating Cylinder

    Science.gov (United States)

    Hosoi, A. E.; Mahadevan, L.

    1997-11-01

    We investigate the axial instability of the free-surface of a viscous fluid in a horizontal cylinder rotating about its major axis. At low rotation rates, the shape of the free-surface appears to be determined by the balance between gravitational and viscous forces. Following earlier work (Benjamin, Pritchard and Tavener), we use an asymptotic expansion in the small parameter α = √Ω ν \\over g R where ν is viscosity, Ω is angular velocity, g is gravity and R is the radius of the cylinder, to derive a simplified evolution equation for the free-surface. This equation is solved numerically to determine the base state with no axial variation, which is then perturbed to examine the onset of unstable axial modes. Various computational results will be presented for the shape of the free-surface and the wavelength of the axial instability. We show that inertia plays an important role in the onset of the instability and we derive the power law λ = γ^1/3 where λ is the wavelength of the axial instability and γ is surface tension.

  15. Light weakly coupled axial forces: models, constraints, and projections

    Science.gov (United States)

    Kahn, Yonatan; Krnjaic, Gordan; Mishra-Sharma, Siddharth; Tait, Tim M. P.

    2017-05-01

    We investigate the landscape of constraints on MeV-GeV scale, hidden U(1) forces with nonzero axial-vector couplings to Standard Model fermions. While the purely vector-coupled dark photon, which may arise from kinetic mixing, is a well-motivated scenario, several MeV-scale anomalies motivate a theory with axial couplings which can be UV-completed consistent with Standard Model gauge invariance. Moreover, existing constraints on dark photons depend on products of various combinations of axial and vector couplings, making it difficult to isolate the effects of axial couplings for particular flavors of SM fermions. We present a representative renormalizable, UV-complete model of a dark photon with adjustable axial and vector couplings, discuss its general features, and show how some UV constraints may be relaxed in a model with nonrenormalizable Yukawa couplings at the expense of fine-tuning. We survey the existing parameter space and the projected reach of planned experiments, briefly commenting on the relevance of the allowed parameter space to low-energy anomalies in π0 and 8Be∗ decay.

  16. Continuous millennial decrease of the Earth's magnetic axial dipole

    Science.gov (United States)

    Poletti, Wilbor; Biggin, Andrew J.; Trindade, Ricardo I. F.; Hartmann, Gelvam A.; Terra-Nova, Filipe

    2018-01-01

    Since the establishment of direct estimations of the Earth's magnetic field intensity in the first half of the nineteenth century, a continuous decay of the axial dipole component has been observed and variously speculated to be linked to an imminent reversal of the geomagnetic field. Furthermore, indirect estimations from anthropologically made materials and volcanic derivatives suggest that this decrease began significantly earlier than direct measurements have been available. Here, we carefully reassess the available archaeointensity dataset for the last two millennia, and show a good correspondence between direct (observatory/satellite) and indirect (archaeomagnetic) estimates of the axial dipole moment creating, in effect, a proxy to expand our analysis back in time. Our results suggest a continuous linear decay as the most parsimonious long-term description of the axial dipole variation for the last millennium. We thus suggest that a break in the symmetry of axial dipole moment advective sources occurred approximately 1100 years earlier than previously described. In addition, based on the observed dipole secular variation timescale, we speculate that the weakening of the axial dipole may end soon.

  17. Amphiregulin Antibody and Reduction of Axial Elongation in Experimental Myopia

    Directory of Open Access Journals (Sweden)

    Wen Jun Jiang

    2017-03-01

    Full Text Available To examine the mechanism of ocular axial elongation in myopia, guinea pigs (age: 2–3 weeks which either underwent unilateral or bilateral lens-induced myopization (group 1 or which were primarily myopic at baseline (group 2 received unilateral intraocular injections of amphiregulin antibody (doses: 5, 10, or 15 μg three times in intervals of 9 days. A third group of emmetropic guinea pigs got intraocular unilateral injections of amphiregulin (doses: 0.25, 0.50 or 1.00 ng, respectively. In each group, the contralateral eyes received intraocular injections of Ringer's solution. In intra-animal inter-eye comparison and intra-eye follow-up comparison in groups 1 and 2, the study eyes as compared to the contralateral eyes showed a dose-dependent reduction in axial elongation. In group 3, study eyes and control eyes did not differ significantly in axial elongation. Immunohistochemistry revealed amphiregulin labelling at the retinal pigment epithelium in eyes with lens-induced myopization and Ringer's solution injection, but not in eyes with amphiregulin antibody injection. Intraocular injections of amphiregulin-antibody led to a reduction of lens-induced axial myopic elongation and of the physiological eye enlargement in young guinea pigs. In contrast, intraocularly injected amphiregulin in a dose of ≤1 ng did not show a significant effect. Amphiregulin may be one of several essential molecular factors for axial elongation.

  18. Method to measure tone of axial and proximal muscle.

    Science.gov (United States)

    Gurfinkel, Victor S; Cacciatore, Timothy W; Cordo, Paul J; Horak, Fay B

    2011-12-14

    The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention.

  19. Modeling effects of axial extension on arterial growth and remodeling.

    Science.gov (United States)

    Valentín, Arturo; Humphrey, Jay D

    2009-09-01

    Diverse mechanical perturbations elicit arterial growth and remodeling responses that appear to optimize structure and function so as to promote mechanical homeostasis. For example, it is well known that functional adaptations to sustained changes in transmural pressure and blood flow primarily affect wall thickness and caliber to restore circumferential and wall shear stresses toward normal. More recently, however, it has been shown that changes in axial extension similarly prompt dramatic cell and matrix reorganization and turnover, resulting in marked changes in unloaded geometry and mechanical behavior that presumably restore axial stress toward normal. Because of the inability to infer axial stress from in vivo measurements, simulations are needed to examine this hypothesis and to guide the design of future experiments. In this paper, we show that a constrained mixture model predicts salient features of observed responses to step increases in axial extension, including marked increases in fibrous constituent production, leading to a compensatory lengthening that restores original mechanical behavior. Because axial extension can be modified via diverse surgical procedures, including bypass operations, and exploited in tissue regeneration research, there is a need for increased attention to this important aspect of arterial biomechanics and mechanobiology.

  20. Method to Measure Tone of Axial and Proximal Muscle

    Science.gov (United States)

    Gurfinkel, Victor S.; Cacciatore, Timothy W.; Cordo, Paul J.; Horak, Fay B.

    2011-01-01

    The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs1, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention. PMID:22214974

  1. Rotordynamics of Turbine Labyrinth Seals with Rotor Axial Shifting

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Rotors in high-performance steam turbines experience a significant axial shifting during starting and stopping processes due to thermal expansion, for example. This axial shifting could significantly alter the flow pattern and the flow-induced rotordynamic forces in labyrinth seals, which in turn, can considerably affect the rotor-seal system performance. This paper investigates the influence of the rotor axial shifting on leakage rate as well as rotordynamic forces in high-low labyrinth seals over a range of seal clearances and inlet swirl velocities. A well-established CFD-perturbation model was employed to predict the rotordynamic coefficients. A surprisingly large effect was detected for rotordynamic characteristics due to rotor shifting. It was also found that a less destabilizing effect arose from rotor axial shifting in the leakage flow direction, whereas a more destabilizing effect arose from shifting against the leakage flow direction. Further, a tentative explanation was proposed for the large sensitivities of dynamic forces to rotor axial shifting.

  2. Helical tomo-therapy for axial and para-spinal tumours: Experience of Institut Bergonie (14 cases); Experience de l'institut Bergonie a propos de 14 cas de tomotherapie helicoidale de tumeurs axiales et para-axiales

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, H.; Dejean, C.; Henriques de Figueiredo, B.; Sargos, P.; Caron, J. [Departement de radiotherapie, institut Bergonie, centre regional de lutte contre le cancer de Bordeaux et du Sud-Ouest, 229, cours de l' Argonne, 33076 Bordeaux cedex (France); Stoeckle, E. [Departement de chirurgie, institut Bergonie, centre regional de lutte contre le cancer de Bordeaux et du Sud-Ouest, 229, cours de l' Argonne, 33076 Bordeaux cedex (France); Bui, B.N.; Italiano, A. [Departement d' oncologie medicale, institut Bergonie, centre regional de lutte contre le cancer de Bordeaux et du Sud-Ouest, 229, cours de l' Argonne, 33076 Bordeaux cedex (France); Gille, O. [Service d' orthopedie, groupe hospitalier Pellegrin, CHU de Bordeaux, place Amelie-Raba-Leon, 33076 Bordeaux cedex (France); Kantor, G. [Departement de radiotherapie, institut Bergonie, centre regional de lutte contre le cancer de Bordeaux et du Sud-Ouest, 229, cours de l' Argonne, 33076 Bordeaux cedex (France); Universite Victor-Segalen Bordeaux 2, 146, rue Leo-Saignat, 33076 Bordeaux cedex (France)

    2011-08-15

    Purpose. - To evaluate the feasibility of helical tomo-therapy intensity-modulated radiotherapy for the treatment of axial and para-spinal tumours. Patients and methods. - Fourteen consecutive patients with axial and para-spinal tumours at the Bergonie Institute between June 2007 and June 2009 were analysed. Various localizations were observed: four paravertebral tumours, five primitive vertebral tumours and six ilio-sacral or sacral tumours. Results. - The dose prescribed to the median of the planning target volume (PTV) varied from 45 to 68 Gy depending on histology. The maximum dose delivered to the PTV (D near max or D 2%) was 60.6 Gy (range 46.3-69.1). In the five cases where the tumour was located close to the spinal cord, the median value of D near max was 40.1 Gy (range 37.8-45.4). In the seven where the tumour was situated close to the cauda equina, the median value of D near max was 46.5 Gy (range 39.2-60). For two cases in whom the sciatic nerve was the nervous structure at risk, the D near max was 64.4 and 67 Gy. Six patients were in complete remission, six patients suffered a relapse at a median follow-up of 14.5 months (4-24), two died following local tumour progression and metastasis, tumoral stabilisation had been obtained in two patients. Treatment was well tolerated and was never interrupted in all patients. Conclusions. - Results from this preliminary series are encouraging, particularly concerning the good tolerance of this new intensity-modulated radiotherapy presently more available than proton therapy. (authors)

  3. Axially modulated arch resonator for logic and memory applications

    KAUST Repository

    Hafiz, Md Abdullah Al

    2018-01-17

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency is modulated through an axial electrostatic force from the guided side of the microbeam. A multi-physics finite element model is used to verify the effectiveness of the axial modulation. We present two case studies: first, a reconfigurable two-input logic gate based on the linear resonance frequency modulation, and second, a memory element based on the hysteretic frequency response of the resonator working in the nonlinear regime. The energy consumptions of the device for both logic and memory operations are in the range of picojoules, promising for energy efficient alternative computing paradigm.

  4. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis

    DEFF Research Database (Denmark)

    Lambert, Robert G W; Bakker, Pauline A C; van der Heijde, Désirée

    2016-01-01

    OBJECTIVES: To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA). METHODS: The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI...... for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording...... of the existing definition was examined in detail and the data and a draft proposal were presented to and voted on by the ASAS membership. RESULTS: The clear presence of bone marrow oedema on MRI in subchondral bone is still considered to be the defining observation that determines the presence of active...

  5. In vivo classification of breast masses using features derived from axial-strain and axial-shear images.

    Science.gov (United States)

    Xu, Haiyan; Varghese, Tomy; Jiang, Jingfeng; Zagzebski, James A

    2012-10-01

    Breast cancer is currently the second leading cause of cancer deaths in women. Early detection and accurate classification of suspicious masses as benign or malignant is important for arriving at an appropriate treatment plan. In this article, we present classification results for features extracted from ultrasound-based, axial-strain and axial-shear images of breast masses. The breast-mass stiffness contrast, size ratio, and a normalized axial-shear strain area feature are evaluated for the classification of in vivo breast masses using a leave-one-out classifier. Radiofrequency echo data from 123 patients were acquired using Siemens Antares or Elegra clinical ultrasound systems during freehand palpation. Data from four different institutions were analyzed. Axial displacements and strains were estimated using a multilevel, pyramid-based two-dimensional cross-correlation algorithm, with final processing block dimensions of 0.385 mm × 0.507 mm (three A-lines). Since mass boundaries on B-mode images for 21 patients could not be delineated (isoechoic), the combined feature analysis was only performed for 102 patients. Results from receiver operating characteristic (ROC) demonstrate that the area under the curve was 0.90, 0.84, and 0.52 for the normalized axial-shear strain, size ratio, and stiffness contrast, respectively. When these three features were combined using a leave-one-out classifier and support vector machine approach, the overall area under the curve improved to 0.93.

  6. Nonlinear Response of Thin Cylindrical Shells with Longitudinal Cracks and Subjected to Internal Pressure and Axial compression Loads

    Science.gov (United States)

    Starnes, James H.; Rose, Cheryl A.

    1998-01-01

    The results of an analytical study of the nonlinear response of a thin unstiffened aluminum cylindrical shell with a longitudinal crack are presented. The shell is analyzed with a nonlinear shell analysis code that maintains the shell in a nonlinear equilibrium state while the crack is grown. The analysis accurately accounts for global and local structural response phenomena. Results are presented for internal pressure, axial compression, and combined internal pressure and axial compression loads. The effects of varying crack length on the nonlinear response of the shell subjected to internal pressure are described. The effects of varying crack length on the prebuckling, buckling and postbuckling responses of the shell subjected to axial compression, and subjected to combined internal pressure and axial compression are also described. The results indicate that the nonlinear interaction between the in-plane stress resultants and the out-of-plane displacements near a crack can significantly affect the structural response of the shell. The results also indicate that crack growth instabilities and shell buckling instabilities can both affect the response of the shell as the crack length is increased.

  7. Spectral analysis in thin tubes with axial heterogeneities

    KAUST Repository

    Ferreira, Rita

    2015-01-01

    In this paper, we present the 3D-1D asymptotic analysis of the Dirichlet spectral problem associated with an elliptic operator with axial periodic heterogeneities. We extend to the 3D-1D case previous 3D-2D results (see [10]) and we analyze the special case where the scale of thickness is much smaller than the scale of the heterogeneities and the planar coefficient has a unique global minimum in the periodic cell. These results are of great relevance in the comprehension of the wave propagation in nanowires showing axial heterogeneities (see [17]).

  8. Axial Permanent Magnet Generator for Wearable Energy Harvesting

    DEFF Research Database (Denmark)

    Högberg, Stig; Sødahl, Jakob Wagner; Mijatovic, Nenad

    2016-01-01

    An increasing demand for battery-free electronics is evident by the rapid increase of wearable devices, and the design of wearable energy harvesters follows accordingly. An axial permanent magnet generator was designed to harvest energy from human body motion and supplying it to a wearable...... application. The design was approached from an lectromagnetic point of view in this article. Two types of axial flux permanent magnet generators were designed: one with an iron yoke, which is commonly used to reduce the machine volume and demand of permanent magnets, and a second without the iron yoke...

  9. Periodicity effects of axial waves in elastic compound rods

    DEFF Research Database (Denmark)

    Nielsen, R. B.; Sorokin, S. V.

    2015-01-01

    Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase-closure Prin......Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase...

  10. Scattering of axially channeled particles by atomic strings in crystals

    Energy Technology Data Exchange (ETDEWEB)

    Cherdyntsev, V.V.; Pokhil, G.P.; Ryabov, V.A. (Moskovskij Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki)

    1983-06-01

    The motion of axially channeled particles at shallow depths is analytically treated. It is shown that there may exist finite trajectories for particles with energies of the order of the critical energy. The effect of focusing upon backscattering yield oscillations is examined. For the transition from axial channeling to planar one, the self-consistent solution of the equations of motion is obtained, which allows to take an exact account of the discrete arrangement of atomic rows making up a planar channel. An analysis of this solution offers a new interpretation of the processes occuring at such transitions.

  11. Numerical simulation of breakup and detachment of an axially ...

    Indian Academy of Sciences (India)

    The extensional, breakup and detachment dynamics of an axially stretching Newtonian liquid bridge are investigated numerically with a dynamic domain multiphase incompressible flow solver. The multiphase flow solver employs a Cahn–Hilliard phase field model to describe the evolution of the diffuse interfaceseparating ...

  12. Axial drive to nonlinear flow between rotating cylinders

    Science.gov (United States)

    Ashrafi, Nariman; Hazbavi, Abbas

    2014-02-01

    Stability of pseudoplastic rotational flow between cylinders in presence of an independent axial component is investigated. The fluid is assumed to follow the Carreau model and mixed boundary conditions are imposed. The conservation of mass and momentum equations give rise to a four-dimensional low-order dynamical system, including additional nonlinear terms in the velocity components originated from the shear-dependent viscosity. In absence of the axial flow, as the pseudoplasticity effects increases, the purely-azimuthal base flow loses its stability to the vortex structure at a lower critical Taylor number. Emergence of the vortices corresponds to the onset of a supercritical bifurcation also present in the flow of a linear fluid. However, unlike the Newtonian case, pseudoplastic Taylor vortices lose their stability as the Taylor number reaches a second critical number corresponding to the onset of a Hopf bifurcation. Existence of an axial flow induced by a pressure gradient appears to further advance each critical point on the bifurcation diagram. In continuation, complete flow field together with viscosity maps is analyzed for different flow scenarios. Through evaluation of the Lyapunov exponent, flow stability and temporal behavior of the system for cases with and without axial flow are brought to attention.

  13. sizing of wind powered axial flux permanent magnet alternator using

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... In this work, a wind-powered, single-phase, permanent magnet alternator utilizing an axial flux distribution system is developed. Using analytical calculations, the design parameters of the alternator's main dimensions were obtained in a similar procedure for conventional electrical machines. To prove the ...

  14. A cylindrical drift chamber with azimuthal and axial position readout

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Yam, Z.; Cummings, J.P.; Dowd, J.P.; Eugenio, P.; Hayek, M.; Kern, W.; King, E.; Shenhav, N.; Chung, S.U.; Hackenburg, R.W.; Olchanski, C.; Weygand, D.P.; Willutzki, H.J.; Brabson, B.B.; Crittenden, R.R.; Dzierba, A.R.; Gunter, J.; Lindenbusch, R.; Rust, D.R.; Scott, E.; Smith, P.T.; Sulanke, T.; Teige, S.; Denisov, S.; Dushkin, A.; Kochetkov, V.; Lipaev, V.; Popov, A.; Shein, I.; Soldatov, A.; Anoshina, E.V.; Bodyagin, V.A.; Demianov, A.I.; Gribushin, A.M.; Kodolova, O.L.; Korotkikh, V.L.; Kostin, M.A.; Ostrovidov, A.I.; Sarycheva, L.I.; Sinev, N.B.; Vardanyan, I.N.; Yershov, A.A.; Adams, T.; Bishop, J.M.; Cason, N.M.; Sanjari, A.H.; LoSecco, J.M.; Manak, J.J.; Shephard, W.D.; Stienike, D.L.; Taegar, S.A.; Thompson, D.R.; Brown, D.S.; Pedlar, T.; Seth, K.K.; Wise, J.; Zhao, D.; Adams, G.S.; Napolitano, J.; Nozar, M.; Smith, J.A.; Witkowski, M. [Massachusetts Univ., North Dartmouth, MA (United States)]|[Brookhaven National Laboratory, Upton, L.I., NY 11973 (United States)]|[Indiana University, Bloomington, IN 47405 (United States)]|[Institute for High Energy Physics, Protvino (Russian Federation)]|[Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation)]|[University of Notre Dame, Notre Dame, IN 46556 (United States)]|[Northwestern University, Evanston, IL 60208 (United States)]|[Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    1997-02-21

    A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in {pi}{sup -}p interactions. We describe the chamber`s design considerations, details of its construction, electronics, and performance characteristics. (orig.).

  15. Developmental ossification sequences of the appendicular and axial ...

    African Journals Online (AJOL)

    A pre-hatch developmental study on ossification sequences of axial and appendicular skeletal system in Kuttanad duck embryos was undertaken using 78 viable embryos. From day 3 to day 7 of incubation no ossification densities were seen both by alizarin red staining and computerized radiography. The first indication of ...

  16. Optimal design of multi-conditions for axial flow pump

    Science.gov (United States)

    Shi, L. J.; Tang, F. P.; Liu, C.; Xie, R. S.; Zhang, W. P.

    2016-11-01

    Passage components of the pump device will have a negative flow state when axial pump run off the design condition. Combined with model tests of axial flow pump, this paper use numerical simulation and numerical optimization techniques, and change geometric design parameters of the impeller to optimal design of multi conditions for Axial Flow Pump, in order to improve the efficiency of non-design conditions, broad the high efficient district and reduce operating cost. The results show that, efficiency curve of optimized significantly wider than the initial one without optimization. The efficiency of low flow working point increased by about 2.6%, the designed working point increased by about 0.5%, and the high flow working point increased the most, about 7.4%. The change range of head is small, so all working point can meet the operational requirements. That will greatly reduce operating costs and shorten the period of optimal design. This paper adopted the CFD simulation as the subject analysis, combined with experiment study, instead of artificial way of optimization design with experience, which proves the reliability and efficiency of the optimization design of multi-operation conditions of axial-flow pump device.

  17. Axially Symmetric Bianchi Type-I Bulk-Viscous Cosmological ...

    Indian Academy of Sciences (India)

    Abstract. The present study deals with spatially homogeneous and anisotropic axially symmetric Bianchi type-I cosmological model with time variable cosmological term in the presence of bulk viscous fluid. The Einstein's field equations are solved explicitly by time varying decel- eration parameter q. Consequences of the ...

  18. Integrating public transort networks in the axial model

    NARCIS (Netherlands)

    Gil, J.

    2012-01-01

    This study presents a first step in the development of a model that integrates public transport networks with the space syntax axial model, towards a network model that can describe the multi?modal movement structure of a city and study its patterns and flows. It describes the method for building an

  19. Effect of axial modes on Doppler experiments with gas lasers

    NARCIS (Netherlands)

    Bolwijn, P.T.; Peek, Th.H.; Alkemade, C.T.J.

    1966-01-01

    Power output modulation was obtained by using a moving mirror reflecting one beam back into the laser interferometer. The strong dependence of modulation amplitude on the distance between moving mirror and laser is related to the number, n, of excited axial modes for n > 1.

  20. Axial chromatic aberration of the human eye: frequency or wavelength?

    Science.gov (United States)

    Pease, P L; Barbeito, R

    1989-04-01

    The axial chromatic aberration of the human eye is nearly perfectly described by a linear function when expressed in terms of frequency rather than wavelength. Since linear functions are simple to work with and more readily understood, there are advantages for the expression of these data in terms of frequency.

  1. Landforms along transverse faults parallel to axial zone of folded ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 126; Issue 1. Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun Sub-Himalaya, India. Khayingshing ... Keywords. Himalayan Frontal Thrust; outer Kumaun Himalaya; transverse structure; folded mountain front.

  2. sizing of wind powered axial flux permanent magnet alternator using

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... Using analytical calculations, the design parameters of the alternator's main dimensions were obtained in a ... SIZING OF WIND POWERED AXIAL FLUX PERMANENT MAGNET ALTERNATOR USING ANALYTICAL APPROACH,. A. O. Otuoze, et al .... then be expressed as. Equation (7) can be re-written as.

  3. Atlanto-axial instability in rheumatoid arthritis: a review | Omar ...

    African Journals Online (AJOL)

    High index of suspicion and early intervention results in good outcomes and prevents neurological outcome. Conclusion: Cervical spine involvement in rheumatoid arthritis is common and debilitating. Atlanto-axial instability is the commonest form. Early diagnosis and treatment is key in management. Early selective choice ...

  4. Fatigue Limit of Axially Compressed Concrete | Levchich | Nigerian ...

    African Journals Online (AJOL)

    An attempt to evaluate analytically the fatigue limit of axially loaded concrete depending upon the load parameters, number of load cycles and static short-term strength is presented. The conventional limit of concrete microcracking statical sustained strength of concrete, curvelinear relationship between fatigue limit and load ...

  5. Ocular Axial Length and Keratometry Readings of Normal Eyes in ...

    African Journals Online (AJOL)

    Aim: To provide average axial length and keratometry readings in healthy eyes of people in Rivers and surrounding states in southern Nigeria. This may guide the purchase of intraocular lens in the study area. Materials and methods: Four hundred consecutive patients with 800 non-cataractous eyes attending the eye clinic ...

  6. first principles derivation of a stress function for axially symmetric

    African Journals Online (AJOL)

    HOD

    In this work, a stress function is derived from first principles to describe the behaviour of three dimensional axially symmetric elasticity problems involving linear elastic, isotropic homogeneous materials. In the process, the fifteen governing partial differential equations of linear isotropic elasticity were reduced to the solution ...

  7. Axial phenoxide coordination on di-iron(III) bisporphyrin: Insights ...

    Indian Academy of Sciences (India)

    Abstract. Synthesis, structure and properties of new five-coordinate phenolate complexes of di-iron(III) bis- porphyrin are reported here, in which phenol binds in η1-fashion as an axial ligand. The solid and solu- tion EPR at 120 K and 1H NMR spectral pattern in solution provide unequivocal evidence for the high spin.

  8. On the generation techniques of axially symmetric stationary metrics

    Indian Academy of Sciences (India)

    General relativity; Einstein's equations; relation between solution generating techniques; soliton technique; method of Gutsunaev–Manko. ... and the soliton technique (for two-soliton solutions) of Belinskii–Zakharov, for generating solutions of axially symmetric stationary space-times in general relativity is discussed.

  9. 3-D Simulation of Vertical-Axial Tidal Current Turbine

    Directory of Open Access Journals (Sweden)

    Zhiyang Zhang

    2016-12-01

    Full Text Available Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.

  10. Perturbation approximation for orbits in axially symmetric funnels

    Science.gov (United States)

    Nauenberg, Michael

    2014-11-01

    A perturbation method that can be traced back to Isaac Newton is applied to obtain approximate analytic solutions for objects sliding in axially symmetric funnels in near circular orbits. Some experimental observations are presented for balls rolling in inverted cones with different opening angles, and in a funnel with a hyperbolic surface that approximately simulates the gravitational force.

  11. Etanercept for the treatment of non-radiographic axial spondyloarthritis.

    Science.gov (United States)

    Rios Rodriguez, Valeria; Poddubnyy, Denis

    2016-01-01

    Presently, tumor necrosis factor α antagonist therapy is the only effective alternative treatment to nonsteroidal anti-inflammatory drugs for the entire spectrum of axial spondyloarthritis, including non-radiographic and radiographic (=ankylosing spondylitis) forms. Recently, etanercept has been approved by the European Medicines Agency for the treatment of non-radiographic axial spondyloarthritis, increasing the number of available treatment options for this indication. The latest data on etanercept concerning clinical efficacy and safety in short-term and long-term treatment of patients with non-radiographic axial spondyloarthritis who do not respond to the first-line therapy with non-steroidal anti-inflammatory drugs suggests good efficacy and safety profiles similar to that observed previously in ankylosing spondylitis. This article reviews recent data on the efficacy and safety of etanercept and is focused on the treatment of non-radiographic axial spondyloarthritis. This article will also discuss the role of etanercept in the context of current and developing treatment options.

  12. On the generation techniques of axially symmetric stationary metrics

    Indian Academy of Sciences (India)

    On the generation techniques of axially symmetric stationary metrics. S CHAUDHURI. Department of Physics, Gushkara Mahavidyalaya, Gushkara, Burdwan 713 128, India. Address for correspondence: Chaudhuri Lane, R.K. Palli, Badamtala, Burdwan 713 101, India. MS received 18 October 2000; revised 1 June 2001.

  13. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    Also, the EMSE performance of multi-axial fabrics was found better than their reinforced composites. The best EMSE results were obtained for the ... Author Affiliations. RAMAZAN ERDEM1. Department of Textile Technology, Serik G.S. Süral Vocational School of Higher Education, Akdeniz University, 07500 Antalya, Turkey ...

  14. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    2017-12-05

    Dec 5, 2017 ... Aim/Background: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. Materials and Methods: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile-Ife, South West ...

  15. NORMAL AXIAL ANGLES OF THE KNEE JOINT IN ADULT ...

    African Journals Online (AJOL)

    hi-tech

    2003-08-01

    Aug 1, 2003 ... recommend the establishment of normal ranges of axial angles as a prerequisite for proper orthopaedic clinical practice in this part of the world. REFERENCES. 1. Nigel P., Derek F. and Roger S. The hip joint . In: Anatomy and human movement - structure and function. Ed. 3, Oxford Butterwoth - Heinemann ...

  16. On aspects of vibration of axially moving continua

    NARCIS (Netherlands)

    Hageraats-Ponomareva, S.

    2009-01-01

    In axially moving structures like conveyor belt systems, magnetic tapes, and so on, vibrations occur due to the presence of different kinds of imperfections in the systems. For these structures internal resonances can lead to severe vibrations. Resonance free conveyor belt systems can be constructed

  17. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    Meckel's diverticulum (MD) is a commonly encountered congenital anomaly of the small intestine. We report an extremely unusual case of an axially torted, gangrenous MD presenting as acute intestinal obstruction. A 26-year-old male patient presented to our emergency department with 3 days history of abdominal pain, ...

  18. Report on the Dynamical Evolution of an Axially Symmetric Quasar ...

    Indian Academy of Sciences (India)

    The role of the angular momentum in the regular or chaotic character of motion in an axially symmetric quasar model is examined. It is found that, for a given value of the critical angular momentum , there are two values of the mass of the nucleus for which transition from regular to chaotic motion occurs.

  19. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    Aim/Background: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. Materials and Methods: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile‑Ife, South West Nigeria, free of ...

  20. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Aim/Background: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. Materials and Methods: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile-Ife, South West ...

  1. Kinetics and equilibria for the axial ligation of bromomethyl (aqua ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 6. Kinetics and equilibria for the axial ligation of bromomethyl (aqua)cobaloxime with pyridines - Isolation characterization and DNA binding. Kotha Laxma Reddy K Ashwini Kumar N Ravi Kumar Reddy Penumaka Nagababu A Panasa Reddy S ...

  2. Static Tension Tests on Axially Loaded Pile Segments in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    This paper provides laboratory test results of static axially loaded piles in sand. With a newly developed test setup, the pile-soil interface friction was investigated by using an open-ended steel pile segment with a diameter of 0.5 m. Use of a pile length of 1 m enabled the pile-soil interface...

  3. Comparison of design methods for axially loaded buckets in sand

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2015-01-01

    A study of the present knowledge about the bucket resistance for axial loading was performed considering analytical and numerical design methods as well as physical models. A case study was performed with two bucket foundations of equal diameter, but different skirt lengths installed in dense san...

  4. Aryabha~a and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    GENERAL I ARTICLE. Aryabha~a and Axial Rotation of Earth. 2. Naksatra ... there are plenty of articles on Aryabhata, their contents have remained confined to research journals and ...... system often called the "Bh- iitasankhya" (whose roots too can be traced to Vedic literature) or adopted a Classical alphabetical decimal ...

  5. String-localized quantum fields and modular localization

    Energy Technology Data Exchange (ETDEWEB)

    Mund, J. [Juiz de Fora Univ., MG (Brazil). Dept. de Fisica; Schroer, B. [FU-Berlin, Berlin (Germany). Inst. fuer Theoretische Physik; Yngvason, J. [Erwin Schroedinger Institute for Mathematical Physics, Vienna (Austria)

    2005-12-15

    We study free, covariant, quantum (Bose) fields that are associated with irreducible representations of the Poincare group and localized in semi-infinite strings extending to spacelike infinity. Among these are fields that generate the irreducible representations of mass zero and infinite spin that are known to be incompatible with point-like localized fields. For the massive representation and the massless representations of finite helicity, all string-localized free fields can be written as an integral, along the string, of point-localized tensor or spinor fields. As a special case we discuss the string-localized vector fields associated with the point-like electromagnetic field and their relation to the axial gauge condition in the usual setting. (author)

  6. [Investigations on the prevalence of axial and refractive anisometropia].

    Science.gov (United States)

    Majdanik, Ewa; Czepita, Damian; Safranow, Krzysztof

    2012-01-01

    The aim of this paper was to describe the prevalence of axial and refractive anisometropia among students 18 years old. The study was carried out among high school students 18 years old in Szczecin, Poland. A total of 1040 students including 381 boys and 659 girls were examined. Every student underwent retinoscopy after cycloplegia using 1% Tropicamide. The differences in spherical equivalents in the right and left eye, were calculated. Students who had anisometropia >1.00 Dsph, were qualified to the next part of the studies, in which examinations using an autorefractometer, keratometer, biometric ultrasounds as well as the IOL Master were carried out. In the group of 70 students (which makes up 7% of the examined population), qualified to the next part of the examinations, a total of 20 participants (2%) declined. The remaining 50 students (5%) were divided into two groups. One group consisted of students with axial anisometropia, while the other consisted of students with refractive anisometropia. All of the collected data were stored in an electronic database using the Microsoft EXCEL computer program and analyzed with Statistica 6.1 software. In the analysis of nominal variables the Fisher exact test was used. P values of less than 0.05 were considered statistically significant. In the conducted studies a higher prevalence of axial anisometropia (60%) compared to refractive anisometropia (40%) was observed, but the difference did not reach statistical significance (p = 0.20). No association between the type of anisometropia and gender was found in the studies. Axial anisometropia was found in 60% of boys and girls in the study group qualified to the second part of the examinations, while refractive anisometropia was found in 40% of boys and girls qualified to the next part of the examinations. Anisometropia in students 18 years old is caused more often by different axial length rather than by different refraction of the eye.

  7. High-resolution axial MR imaging of tibial stress injuries

    Science.gov (United States)

    2012-01-01

    Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries. PMID:22574840

  8. The Nucleon Axial Form Factor and Staggered Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Aaron Scott [Chicago U.

    2017-01-01

    The study of neutrino oscillation physics is a major research goal of the worldwide particle physics program over the upcoming decade. Many new experiments are being built to study the properties of neutrinos and to answer questions about the phenomenon of neutrino oscillation. These experiments need precise theoretical cross sections in order to access fundamental neutrino properties. Neutrino oscillation experiments often use large atomic nuclei as scattering targets, which are challenging for theorists to model. Nuclear models rely on free-nucleon amplitudes as inputs. These amplitudes are constrained by scattering experiments with large nuclear targets that rely on the very same nuclear models. The work in this dissertation is the rst step of a new initiative to isolate and compute elementary amplitudes with theoretical calculations to support the neutrino oscillation experimental program. Here, the eort focuses on computing the axial form factor, which is the largest contributor of systematic error in the primary signal measurement process for neutrino oscillation studies, quasielastic scattering. Two approaches are taken. First, neutrino scattering data on a deuterium target are reanalyzed with a model-independent parametrization of the axial form factor to quantify the present uncertainty in the free-nucleon amplitudes. The uncertainties on the free-nucleon cross section are found to be underestimated by about an order of magnitude compared to the ubiquitous dipole model parametrization. The second approach uses lattice QCD to perform a rst-principles computation of the nucleon axial form factor. The Highly Improved Staggered Quark (HISQ) action is employed for both valence and sea quarks. The results presented in this dissertation are computed at physical pion mass for one lattice spacing. This work presents a computation of the axial form factor at zero momentum transfer, and forms the basis for a computation of the axial form factor momentum dependence

  9. Axial differentiation and early gastrulation stages of the pig embryo.

    Science.gov (United States)

    Hassoun, Romia; Schwartz, Peter; Feistel, Kerstin; Blum, Martin; Viebahn, Christoph

    2009-12-01

    Differentiation of the principal body axes in the early vertebrate embryo is based on a specific blueprint of gene expression and a series of transient axial structures such as Hensen's node and the notochord of the late gastrulation phase. Prior to gastrulation, the anterior visceral endoderm (AVE) of the mouse egg-cylinder or the anterior marginal crescent (AMC) of the rabbit embryonic disc marks the anterior pole of the embryo. For phylogenetic and functional reasons both these entities are addressed here as the mammalian anterior pregastrulation differentiation (APD). However, mouse and rabbit show distinct structural differences in APD and the molecular blueprint, making the search of general rules for axial differentiation in mammals difficult. Therefore, the pig was analysed here as a further species with a mammotypical flat embryonic disc. Using light and electron microscopy and in situ hybridisation for three key genes involved in early development (sox17, nodal and brachyury), two axial structures of early gastrulation in the pig were identified: (1) the anterior hypoblast (AHB) characterised by increased cellular height and density and by sox17 expression, and (2) the early primitive streak characterised by a high pseudostratified epithelium with an almost continuous but unusually thick basement membrane, by localised epithelial-mesenchymal transition, and by brachyury expression in the epiblast. The stepwise appearance of these two axial structures was used to define three stages typical for mammals at the start of gastrulation. Intriguingly, the round shape and gradual posterior displacement of the APD in the pig appear to be species-specific (differing from all other mammals studied in detail to date) but correlate with ensuing specific primitive streak and extraembryonic mesoderm development. APD and, hence, the earliest axial structure presently known in the mammalian embryo may thus be functionally involved in shaping extraembryonic membranes and

  10. Non-steroidal anti-inflammatory drugs (NSAIDs) for axial spondyloarthritis (ankylosing spondylitis and non-radiographic axial spondyloarthritis)

    NARCIS (Netherlands)

    Kroon, Feline P. B.; van der Burg, Lennart R. A.; Ramiro, Sofia; Landewé, Robert B. M.; Buchbinder, Rachelle; Falzon, Louise; van der Heijde, Désirée

    2015-01-01

    Axial spondyloarthritis (axSpA) comprises ankylosing spondylitis (radiographic axSpA) and non-radiographic (nr-)axSpA and is associated with psoriasis, uveitis and inflammatory bowel disease. Non-steroidal anti-inflammatory drugs (NSAIDs) are recommended as first-line drug treatment. To determine

  11. Experimental Tests on the Composite Foam Sandwich Pipes Subjected to Axial Load

    Science.gov (United States)

    Li, Feng; Zhao, QiLin; Xu, Kang; Zhang, DongDong

    2015-12-01

    Compared to the composite thin-walled tube, the composite foam sandwich pipe has better local flexural rigidity, which can take full advantage of the high strength of composite materials. In this paper, a series of composite foam sandwich pipes with different parameters were designed and manufactured using the prefabricated polyurethane foam core-skin co-curing molding technique with E-glass fabric prepreg. The corresponding axial-load compressive tests were conducted to investigate the influence factors that experimentally determine the axial compressive performances of the tubes. In the tests, the detailed failure process and the corresponding load-displacement characteristics were obtained; the influence rules of the foam core density, surface layer thickness, fiber ply combination and end restraint on the failure modes and ultimate bearing capacity were studied. Results indicated that: (1) the fiber ply combination, surface layer thickness and end restraint have a great influence on the ultimate load bearing capacity; (2) a reasonable fiber ply combination and reliable interfacial adhesion not only optimize the strength but also transform the failure mode from brittle failure to ductile failure, which is vital to the fully utilization of the composite strength of these composite foam sandwich pipes.

  12. A high-order model of rotating stall in axial compressors with inlet distortion

    Directory of Open Access Journals (Sweden)

    Peng LIN

    2017-06-01

    Full Text Available In this paper, a high-order distortion model is proposed for analyzing the rotating stall inception process induced by inlet distortion in axial compressors. A distortion-generating screen in the compressor inlet is considered. By assuming a quadratic function for the local flow total pressure-drop, the existing Mansoux model is extended to include the effects of static inlet distortion, and a new high-order distortion model is derived. To illustrate the effectiveness of the distortion model, numerical simulations are performed on an eighteenth-order model. It is demonstrated that long length-scale disturbances emerge out of the distorted background flow, and further induce the onset of rotating stall in advance. In addition, the circumferential non-uniform distribution and time evolution of the axial flow are also shown to be consistent with the existing features. It is thus shown that the high-order distortion model is capable of describing the transient behavior of stall inception and will contribute further to stall detection under inlet distortion.

  13. Reassessing the Plastic Hinge Model for Energy Dissipation of Axially Loaded Columns

    Directory of Open Access Journals (Sweden)

    R. M. Korol

    2014-01-01

    Full Text Available This paper investigates the energy dissipation potential of axially loaded columns and evaluates the use of a plastic hinge model for analysis of hi-rise building column collapse under extreme loading conditions. The experimental program considered seven axially loaded H-shaped extruded aluminum structural section columns having slenderness ratios that would be typical of floor-to-ceiling heights in buildings. All seven test specimens initially experienced minor-axis overall buckling followed by formation of a plastic hinge at the mid-height region, leading to local buckling of the flanges on the compression side of the plastic hinge, and eventual folding of the compression flanges. The experimental energy absorption, based on load-displacement relations, was compared to the energy estimates based on section plastic moment resistance based on measured yield stress and based on measured hinge rotations. It was found that the theoretical plastic hinge model underestimates a column’s actual ability to absorb energy by a factor in the range of 3 to 4 below that obtained from tests. It was also noted that the realizable hinge rotation is less than 180°. The above observations are based, of course, on actual columns being able to sustain high tensile strains at hinge locations without fracturing.

  14. Breaking of axial symmetry in excited nuclei as identified in experimental data

    Science.gov (United States)

    Junghans, Arnd R.; Grosse, Eckart; Massarczyk, Ralph

    2017-09-01

    A phenomenological prediction for radiative neutron capture is presented and compared to recent compilations of Maxwellian averaged cross sections and average radiative widths. Photon strength functions and nuclear level densities near the neutron separation energy are extracted from data without the assumption of axial symmetry - at variance to common usage. A satisfactory description is reached with a small number of global parameters when theoretical predictions on triaxiality (from constrained HFB calculations with the Gogny D1S interaction) are inserted into conventional calculations of radiative neutron capture. The photon strength is parametrized using the sum of three Lorentzians (TLO) in accordance to the dipole sum rule. The positions and widths are accounted for by the droplet model with surface dissipation without locally adjusted parameters. Level densities are influenced strongly by the significant collective enhancement based on the breaking of axial symmetry. With the less stringent requirement of invariance against rotation by 180∘ a global set of parameters which allows to describe the photon strength function and the level densities in the nuclear mass range from mass number 50 < A < 250 is found.

  15. Breaking of axial symmetry in excited nuclei as identified in experimental data

    Directory of Open Access Journals (Sweden)

    Junghans Arnd R.

    2017-01-01

    Full Text Available A phenomenological prediction for radiative neutron capture is presented and compared to recent compilations of Maxwellian averaged cross sections and average radiative widths. Photon strength functions and nuclear level densities near the neutron separation energy are extracted from data without the assumption of axial symmetry – at variance to common usage. A satisfactory description is reached with a small number of global parameters when theoretical predictions on triaxiality (from constrained HFB calculations with the Gogny D1S interaction are inserted into conventional calculations of radiative neutron capture. The photon strength is parametrized using the sum of three Lorentzians (TLO in accordance to the dipole sum rule. The positions and widths are accounted for by the droplet model with surface dissipation without locally adjusted parameters. Level densities are influenced strongly by the significant collective enhancement based on the breaking of axial symmetry. With the less stringent requirement of invariance against rotation by 180∘ a global set of parameters which allows to describe the photon strength function and the level densities in the nuclear mass range from mass number 50 < A < 250 is found.

  16. Strong interaction between dye molecule and electromagnetic field localized around 1 Nm3 at gaps of nanoparticle dimers by plasmon resonance

    Science.gov (United States)

    Itoh, Tamitake; Yamamoto, Yuko S.

    2017-11-01

    Electronic transition rates of a molecule located at a crevasse or a gap of a plasmonic nanoparticle (NP) dimer are largely enhanced up to the factor of around 106 due to electromagnetic (EM) coupling between plasmonic and molecular electronic resonances. The coupling rate is determined by mode density of the EM fields at the crevasse and the oscillator strength of the local electronic resonance of a molecule. The enhancement by EM coupling at a gap of plasmonic NP dimer enables us single molecule (SM) Raman spectroscopy. Recently, this type of research has entered a new regime wherein EM enhancement effects cannot be treated by conventional theorems, namely EM mechanism. Thus, such theorems used for the EM enhancement effect should be re-examined. We here firstly summarize EM mechanism by using surface-enhanced Raman scattering (SERS), which is common in EM enhancement phenomena. Secondly, we focus on recent two our studies on probing SM fluctuation by SERS within the spatial resolution of sub-nanometer scales. Finally, we discuss the necessity of re-examining the EM mechanism with respect to two-fold breakdowns of the weak coupling assumption: the breakdown of Kasha's rule induced by the ultra-fast plasmonic de-excitation and the breakdown of the weak coupling by EM coupling rates exceeding both the plasmonic and molecular excitonic dephasing rates.

  17. Axial disability and deep brain stimulation in patients with Parkinson disease

    NARCIS (Netherlands)

    Fasano, A.; Aquino, C.C.; Krauss, J.K.; Honey, C.R.; Bloem, B.R.

    2015-01-01

    Axial motor signs-including gait impairment, postural instability and postural abnormalities-are common and debilitating symptoms in patients with advanced Parkinson disease. Dopamine replacement therapy and physiotherapy provide, at best, partial relief from axial motor symptoms. In carefully

  18. Laboratory Test Setup for Cyclic Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2017-01-01

    This paper presents a comprehensive description and the considerations regarding the design of a new laboratory test setup for testing cyclic axially loaded piles in sand. The test setup aims at analysing the effect of axial one-way cyclic loading on pile capacity and accumulated displacements....... Another aim was to test a large diameter pile segment with dimensions resembling full-scale piles to model the interface properties between pile and sand correctly. The pile segment was an open-ended steel pipe pile with a diameter of 0.5 m and a length of 1 m. The sand conditions resembled the dense sand...... determined from the API RP 2GEO standard and from the test results indicated over consolidation of the sand. Two initial one-way cyclic loading tests provided results of effects on pile capacity and accumulated displacements in agreement with other researchers’ test results....

  19. Reduced aniseikonia in axial anisometropia with contact lens correction.

    Science.gov (United States)

    Winn, B; Ackerley, R G; Brown, C A; Murray, F K; Prais, J; St John, M F

    1988-01-01

    Aniseikonia, although present in isometropia, is associated principally with anisometropia and is widely thought to be the result of differences in the retinal image size presented to each eye. This assumes that equating retinal image size results in congruous cortical images. To test this assumption 1 refractive and 17 axial anisometropic subjects were examined to determine the aniseikonia present when corrected with spectacles and contact lenses. Contrary to many previous predictions, based upon Knapp's Law, the presence of equal retinal images resulted in larger aniseikonias than observed when the eyes were presented with unequal retinal images. This suggests that non-optical components have a significant role in the production of the cortical image, and this therefore requires a shift in the way the management of anisometropia is considered clinically. Contact lens correction maintains the aniseikonia at a minimum level in axial as well as refractive anisometropia and offers the clinician an acceptable practical alternative when prescribing for these patients.

  20. Improving axial depth of cut accuracy in micromilling

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2004-01-01

    In order to maintain an optimum cutting speed, the reduction of mill diameters requires machine tools with high rotational speed capabilities. A solution to update existing machine tools is the use of high speed attached spindles. Major drawbacks of these attachments are the high thermal expansion...... and their rapid warming and cooling, which prevent the achievement of a steady state. Several other factors, independent on the tool-workpiece interaction, influence the machining accuracy. The cutting parameter most heavily affected is the axial depth of cut which is the most critical when using micro end mills...... provided with conventional milling machines. This paper presents an investigation aimed at the reduction of the error on the axial depth of cut in micromilling operations, in a workshop environment. A method for tool length correction with sub-micrometer resolution by use of an inductive probe...

  1. Finite-Size Scaling of Vector and Axial Current Correlators

    CERN Document Server

    Damgaard, P H; Jansen, K; Laine, Mikko; Lellouch, L P

    2003-01-01

    Using quenched chiral perturbation theory, we compute the long-distance behaviour of two-point functions of flavour non-singlet axial and vector currents in a finite volume, for small quark masses, and at a fixed gauge-field topology. We also present the corresponding predictions for the unquenched theory at fixed topology. These results can in principle be used to measure the low-energy constants of the chiral Lagrangian, from lattice simulations in volumes much smaller than one pion Compton wavelength. We show that quenching has a dramatic effect on the vector correlator, which is argued to vanish to all orders, while the axial correlator appears to be a robust observable only moderately sensitive to quenching.

  2. First Calculation of Hyperon Axial Couplings from Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Huey-Wen Lin; Konstantinos Orginos

    2007-12-06

    In this work, we report the first lattice calculation of the hyperon axial couplings, using the 2+1-flavor MILC configurations and domain-wall fermion valence quarks. Both the $\\Sigma$ and $\\Xi$ axial couplings are for the first time done in lattice QCD, and we find the numbers with greater precision than previous chiral perturbation theory and large-$N_c$ theory estimate: $g_{\\Sigma\\Sigma} = 0.450(21)_{\\rm stat}(22)_{\\rm syst}$ and $g_{\\Xi\\Xi} = -0.277(15)_{\\rm stat}(16)_{\\rm syst}$. As a side product, we also determine the low-energy chiral parameters $D$ and $F$ extracted from these coupling constants: $D=0.715(6)_{\\rm stat}(6)_{\\rm syst}$ and $F=0.453(5)_{\\rm stat}(5)_{\\rm syst}$.

  3. Axial Ge/Si nanowire heterostructure tunnel FETs

    Energy Technology Data Exchange (ETDEWEB)

    Picraux, Sanuel T [Los Alamos National Laboratory; Daych, Shadi A [Los Alamos National Laboratory

    2010-01-01

    The vapor-liquid-solid (VLS) growth of semiconductor nanowires allows doping and composition modulation along their axis and the realization of axial 1 D heterostructures. This provides additional flexibility in energy band-edge engineering along the transport direction which is difficult to attain by planar materials growth and processing techniques. We report here on the design, growth, fabrication, and characterization of asymmetric heterostructure tunnel field-effect transistors (HTFETs) based on 100% compositionally modulated Si/Ge axial NWs for high on-current operation and low ambipolar transport behavior. We discuss the optimization of band-offsets and Schottky barrier heights for high performance HTFETs and issues surrounding their experimental realization. Our HTFET devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a measured current drive exceeding 100 {mu}A/{mu}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios.

  4. Effect of axial mixing on RDC and PSE columns performance

    CERN Document Server

    Bastani, D

    2001-01-01

    Using the experimental data obtained from two RDC columns at two different sizes (7.62 and 21.9 cm) and one PSE column with 21.5 cm size, the effect of axial mixing on the performance of these columns was studied. Comparison between the experimental and theoretical (neglecting the axial mixing) number of transfer units indicates that, this effect in PSE columns is more than RDC columns (400% and 200% respectively). These results show that this effect can increase the height of the PSE column up to 4 times for a specific efficiency. Also the results show that this effect is more in law interfacial tension systems, which shows no need of application of agitation facilities when these systems are used.

  5. Fast imaging of mean, axial and radial diffusion kurtosis

    DEFF Research Database (Denmark)

    Hansen, Brian; Shemesh, Noam; Jespersen, Sune Nørhøj

    2016-01-01

    Abstract Diffusion kurtosis imaging (DKI) is being increasingly reported to provide sensitive biomarkers of subtle changes in tissue microstructure. However, DKI also imposes larger data requirements than diffusion tensor imaging (DTI), hence, the widespread adaptation and exploration of DKI would...... benefit from more efficient acquisition and computational methods. To meet this demand, we recently developed a method capable of estimating mean kurtosis with only 13 diffusion weighted images. This approach was later shown to provide very accurate mean kurtosis estimates and to be more efficient......'s principal parameters – mean kurtosis, radial kurtosis, and axial kurtosis – using only 19 diffusion weighted images, compared to the current state-of-the-art acquisitions typically requiring about 60 images. The first approach is based on axially symmetric diffusion and kurtosis tensors, presented here...

  6. Numerical analysis of a microwave torch with axial gas injection

    Energy Technology Data Exchange (ETDEWEB)

    Gritsinin, S. I.; Davydov, A. M.; Kossyi, I. A., E-mail: kossyi@fpl.gpi.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Kulumbaev, E. B. [National Research University Belgorod State University (Russian Federation); Lelevkin, V. M. [Kyrgyz-Russian Slavic University (Kyrgyzstan)

    2013-07-15

    The characteristics of a microwave discharge in an argon jet injected axially into a coaxial channel with a shortened inner electrode are numerically analyzed using a self-consistent equilibrium gas-dynamic model. The specific features of the excitation and maintenance of the microwave discharge are determined, and the dependences of the discharge characteristics on the supplied electromagnetic power and gas flow rate are obtained. The calculated results are compared with experimental data.

  7. Modelling of a Bi-axial Vibration Energy Harvester

    Science.gov (United States)

    2013-05-01

    effect of the electrical load on the transduction, and on the mechanical dynamics. It was demonstrated that the back EMF from current flow in the...created with a permanent-magnet/ball-bearing arrangement. The mechanical oscillations of the ball-bearing in response to bi-axial vibrations in a host...system on an aircraft platform. Modelling of the mechanical dynamics and the electromechanical transduction of the harvester is undertaken by: means of

  8. Axial Magnetic Field Effect on Taylor-Couette Flow

    OpenAIRE

    Sofiane ABERKANE; IHDENE malika; mouderes mourad; ghezal abderrahmane

    2015-01-01

    This study is interested in the effect of an axial magnetic field imposed on incompressible flow of electrically conductive fluid between two horizontal coaxial cylinders. The imposed magnetic field is assumed uniform and constant. The effect of heat generation due to viscous dissipation is also taken into account. The inner and outer cylinders are maintained at different uniform temperatures. The movement of the fluid is due to rotation of the cylinder with a constant speed. An exact solutio...

  9. MRI of the axial skeletal manifestations of ankylosing spondylitis

    Energy Technology Data Exchange (ETDEWEB)

    Levine, D.S.; Forbat, S.M.; Saifuddin, A. E-mail: asaifuddin@aol.com

    2004-05-01

    Magnetic resonance imaging (MRI) is a valuable tool in the imaging and assessment of patients with ankylosing spondylitis. MRI can demonstrate the acute and chronic changes of sacroiliitis, osteitis, discovertebral lesions, disc calcifications and ossification and arthopathic lesions, which characterize the disease, as well as the complications, which include fracture and the rare cauda equina syndrome. This article reviews the range of MRI findings commonly seen within the axial skeleton in patients with this condition.

  10. Simulation Method of Cumulative Flow without of Axial Stagnation Point

    Directory of Open Access Journals (Sweden)

    I. V. Minin

    2015-01-01

    Full Text Available The paper describes a developed analytical model of non-stationary formation of a cumulative jet without axial stagnation point. It shows that it is possible to control the weight, size, speed, and momentum of the jet with the parameters, which are not achievable in the classical mode of jet formation. Considered jet formation principle can be used to conduct laboratory simulation of astro-like plasma jets.

  11. Axial Compressor Stall and Surge Prediction by Measurements

    Directory of Open Access Journals (Sweden)

    H. Hönen

    1999-01-01

    Full Text Available The paper deals with experimental investigations and analyses of unsteady pressure distributions in different axial compressors. Based on measurements in a single stage research compressor the influence of increasing aerodynamic load onto the pressure and velocity fluctuations is demonstrated. Detailed measurements in a 14-stage and a 17-stage gas turbine compressor are reported. For both compressors parameters could be found which are clearly influenced by the aerodynamic load.

  12. Modeling Effects of Axial Extension on Arterial Growth and Remodeling

    OpenAIRE

    Valentín, A.; Humphrey, J. D.

    2009-01-01

    Diverse mechanical perturbations elicit arterial growth and remodeling responses that appear to optimize structure and function so as to achieve mechanical homeostasis. For example, it is well known that functional adaptations to sustained changes in transmural pressure and blood flow primarily affect wall thickness and caliber to restore circumferential and wall shear stresses toward normal. More recently, however, it has been shown that changes in axial extension similarly prompt dramatic c...

  13. Simultaneous Rotational and Axial Flow of Nonlinear Fluids

    Science.gov (United States)

    Ashrafi, Nariman; Yektapour, Mehdi; Shafahi, Mehdi

    2017-11-01

    An axial flow is introduced to the rotational flow of pseudoplastic fluids in the gap between concentric cylinders. The outer cylinder is fixed while the inner one has simultaneous and independent rotational and translational motions. The fluid follows the Carreau-Bird model and mixed boundary conditions are imposed. The four-dimensional low-order equations resulted from Galerkin projection of the conservation of mass and momentum equations, includes highly non-linear terms in the velocity components. Without axial flow, stability of the base radial flow is lost to the vortex structure at a lower critical Taylor number, with increase of the fluid pseudoplasticity. The vortices imply onset of a supercritical bifurcation which occurs in the rotational flow of linear fluids as well. In contrast to the Newtonian case, pseudoplastic Taylor vortices lose their stability at a second critical Taylor number is reached a second critical number that corresponds to the onset of a Hopf bifurcation. The axial flow, caused by the translational motion of the inner cylinder advance each critical point on the bifurcation diagram. The flow field and viscosity maps are provided for major stability regions.

  14. HTS axial flux induction motor with analytic and FEA modeling

    Energy Technology Data Exchange (ETDEWEB)

    Li, S., E-mail: alexlee.zn@gmail.com; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J.H.

    2013-11-15

    Highlights: •A high temperature superconductor axial flux induction motor and a novel maglev scheme are presented. •Analytic method and finite element method have been adopted to model the motor and to calculate the force. •Magnetic field distribution in HTS coil is calculated by analytic method. •An effective method to improve the critical current of HTS coil is presented. •AC losses of HTS coils in the HTS axial flux induction motor are estimated and tested. -- Abstract: This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.

  15. Imaging results and TOF studies with axial PET detectors

    CERN Document Server

    Joram, Christian

    2013-01-01

    We have developed a fully operational PET demonstrator setup which allows true 3D reconstruction of the 511 keV photons and therefore leads to practically parallax free images. The AX-PET concept is based on thin 100 mm long scintillation crystals (LYSO), axially oriented and arranged in layers around the held of view. Layers of wavelength shifting plastic strips mounted in between the crystal layers give the axial coordinate. Both crystals and WLS strips are individually read out by G-APD (SiPM) photodetectors. The Fully scalable concept overcomes the dilemma of sensitivity versus spatial resolution which is inherent to classical PET designs. A demonstrator set-up based on two axial modules was exhaustively characterized using point-like sources, phantoms filled with radiotracer and finally rats and a mouse. The results entirely meet the performance expectations ( <2 mm FWHM in all three coordinates over the complete held of view) and also demonstrated the ability to include Compton interactions (inter-cr...

  16. The New Performance Calculation Method of Fouled Axial Flow Compressor

    Directory of Open Access Journals (Sweden)

    Huadong Yang

    2014-01-01

    Full Text Available Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds’ law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail.

  17. Multi technical analysis of wear mechanisms in axial piston pumps

    Science.gov (United States)

    Schuhler, G.; Jourani, A.; Bouvier, S.; Perrochat, J.-M.

    2017-05-01

    Axial piston pumps convert a motor rotation motion into hydraulic or pneumatic power. Their compactness and efficiency of approximately 0.9 make them suitable for actuation applications especially in aeronautics. However, they suffer a limited life due to the wear of their components. In the literature, studies of axial piston pumps deal with contact between its different elements under lubrication conditions. Nevertheless, they are more focused on analytic or numerical approaches. This study consists in an experimental analysis of worn pump components to highlight and understand wear mechanisms. Piston shoes are central components in the axial piston pump since they are involved in three tribological contacts. These three contacts are thereby studied: piston shoes/swashplate, piston shoes/pistons and piston shoes/shoes hold down plate (SHDP). To perform this analysis, helicopter hydraulic pumps after different operating times have been studied. The wear damage mechanisms and wear debris are analysed using SEM observations. 3D surface roughness measurements are then used to characterize worn surfaces. The observations reveal that in the contact between shoes and swashplate, the main wear mechanism is three-body abrasive wear due to coarse carbides removal. Between shoes and pistons, wear occurs in a less severe way and is mainly due to the debris generated in the first contact and conveyed by the lubricating fluid. In the third contact, the debris are also the prime cause of the abrasive wear and the generation of deep craters in the piston shoes.

  18. Servo control system construction for CBHD radial and axial tracking

    Science.gov (United States)

    Cui, Yingchao; Cheng, Xuemin; Ma, Jianshe; Hou, Xinnan

    2010-11-01

    CBHD (China Blue High Definition Disc) is a high-definition optical disc standard with Chinese independent intellectual property. Compared with DVD optical pick-up, CBHD optical pick-up, key component of CBHD player, has significant improvement in the channel bit rate and certain reduction in acceptable tolerance range for disk tilt, etc. This paper specifies the servo control system construction for the CBHD radial tracing and axial tracking. This servo control system should ensure the optical beam of OPU focusing on the Disc plane and following the track of CBHD channel accurately. According to the expected radial/axial maximum acceleration and the limitation of emax, an open-loop transfer function specifying the servo system for axial and radial tracking is introduced. The corresponding servo control algorithm including IIR filter based on the above-mentioned transfer function is theoretically analyzed and numerically simulated by MATLAB. Because optical pick-ups are different in dynamic properties and its digital circuit exist quantization error, time delay nonlinearity, etc, the tuning of IIR parameters is laborious and time-consuming. Thus a experimental platform for CBHD optical pick-up servo system are designed in this paper, and an user-friendly interface for IIR parameters adjustment is given. Experimental results showed that this control system has good servo characteristics in time-domain and frequency-domain.

  19. DOES BONE MINERAL DENSITY CHANGE IN EARLY AXIAL SPONDYLOARTHRITIS?

    Directory of Open Access Journals (Sweden)

    E. E. Gubar

    2016-01-01

    Full Text Available The rate of osteoporosis (OP and the mechanism  of its development in patients with ankylosing spondylitis (AS and other spondyloarthrititides (SpA have not been sufficiently investigated. Steady-state  inflammatory disease activity is anticipated  to be the leading factor of OP in AS.Objective: to investigate lumbar spine (LS and femoral neck (FN  bone mineral density (BMD  in patients with early axial SpA (axSpA and to reveal its association with inflammatory disease activity.Subjects and methods. A total of 150 patients (59 men and 91 women aged 18 to 45 years with inflammatory back pain for ≥3 months and ≤5 years were examined. The diagnosis of axSpA was established in accordance  with the 2009 ASAS criteria. BASDAI and ASDAS-CRP were used to assess activity and functional status was evaluated with BASFI. The examination  included determination of HLA-B27, X-ray of the pelvis and LS, magnetic resonance imaging (MRI  of the sacroiliac joints, LS, and hip joints (in the presence of clinical signs of their involvement,  and densitometry of LS (LI–IV  and FN. By taking into account the patients’ young age, the Z score was used to estimate BMD. The Z-score -2 SD or lower in at the least one of the regions examined is considered to be diminished BMD. Results and discussion. The median Z-score was -0.7 [-1.3; -0.2] SD for FN and -0.9 [-1.6; -0.6] SD for LS. Reduced BMD in at the least one of the regions examined was diagnosed in 27 (18.0% patients. There was lower BMD in LS in 21 (14.0% patients and in FN in 8 (5.3%. Two (1.3% patients were diagnosed as having osteopenia in the two examined regions. There was no association between diminished BMD and age, gender, disease activity assessed with BASDAI, ASDAS-СRP, erythrocyte sedimentation rate (ESR and C-reactive protein (CRP. An association was found between inflammatory LS changes, as evidenced by MRI (MRI spondylitis, and reduced BMD in at least one of the examined regions. MRI

  20. Longitudinal-differential interferometry: direct imaging of axial superluminal phase propagation.

    Science.gov (United States)

    Kim, Myun-Sik; Scharf, Toralf; Etrich, Christoph; Rockstuhl, Carsten; Peter, Hans Herzig

    2012-02-01

    We introduce and demonstrate a new interferometric method called longitudinal-differential (LD) interferometry, which measures the spatially resolved phase difference of the scattered field by an object relative to the illumination. This method is combined with a high-resolution interference microscope that allows recording three-dimensional field distributions in amplitude and phase. The method is applied to study the axial phase behavior of Arago spots, an effect observable in low-Fresnel-number systems behind objects with a size comparable to the wavelength. We directly observe the initial phase delay in the Arago spot and prove that the local phase velocity exceeds the speed of light in air. Such LD phase studies are applicable not only to the Arago spot but also to other kinds of light interactions with wavelength-scale objects, e.g., photonic nanojets.

  1. An FFT-accelerated fdtd scheme with exact absorbing conditions for characterizing axially symmetric resonant structures

    KAUST Repository

    Sirenko, Kostyantyn

    2011-01-01

    An accurate and efficient finite-difference time-domain (FDTD) method for characterizing transient waves interactions on axially symmetric structures is presented. The method achieves its accuracy and efficiency by employing localized and/or fast Fourier transform (FFT) accelerated exact absorbing conditions (EACs). The paper details the derivation of the EACs, discusses their implementation and discretization in an FDTD method, and proposes utilization of a blocked-FFT based algorithm for accelerating the computation of temporal convolutions present in nonlocal EACs. The proposed method allows transient analyses to be carried for long time intervals without any loss of accuracy and provides reliable numerical data pertinent to physical processes under resonant conditions. This renders the method highly useful in characterization of high-Q microwave radiators and energy compressors. Numerical results that demonstrate the accuracy and efficiency of the method are presented.

  2. Physically-Based Reduced Order Modelling of a Uni-Axial Polysilicon MEMS Accelerometer

    Science.gov (United States)

    Ghisi, Aldo; Mariani, Stefano; Corigliano, Alberto; Zerbini, Sarah

    2012-01-01

    In this paper, the mechanical response of a commercial off-the-shelf, uni-axial polysilicon MEMS accelerometer subject to drops is numerically investigated. To speed up the calculations, a simplified physically-based (beams and plate), two degrees of freedom model of the movable parts of the sensor is adopted. The capability and the accuracy of the model are assessed against three-dimensional finite element simulations, and against outcomes of experiments on instrumented samples. It is shown that the reduced order model provides accurate outcomes as for the system dynamics. To also get rather accurate results in terms of stress fields within regions that are prone to fail upon high-g shocks, a correction factor is proposed by accounting for the local stress amplification induced by re-entrant corners. PMID:23202031

  3. Physically-Based Reduced Order Modelling of a Uni-Axial Polysilicon MEMS Accelerometer

    Directory of Open Access Journals (Sweden)

    Sarah Zerbini

    2012-10-01

    Full Text Available In this paper, the mechanical response of a commercial off-the-shelf, uni-axial polysilicon MEMS accelerometer subject to drops is numerically investigated. To speed up the calculations, a simplified physically-based (beams and plate, two degrees of freedom model of the movable parts of the sensor is adopted. The capability and the accuracy of the model are assessed against three-dimensional finite element simulations, and against outcomes of experiments on instrumented samples. It is shown that the reduced order model provides accurate outcomes as for the system dynamics. To also get rather accurate results in terms of stress fields within regions that are prone to fail upon high-g shocks, a correction factor is proposed by accounting for the local stress amplification induced by re-entrant corners.

  4. Axially Symmetric-dS Solution in Teleparallel f(T Gravity Theories

    Directory of Open Access Journals (Sweden)

    Gamal G. L. Nashed

    2015-01-01

    Full Text Available We apply a tetrad field with six unknown functions to Einstein field equations. Exact vacuum solution, which represents axially symmetric-dS spacetime, is derived. We multiply the tetrad field of the derived solution by a local Lorentz transformation which involves a generalization of the angle ϕ and get a new tetrad field. Using this tetrad, we get a differential equation from the scalar torsion T=TαμνSαμν. Solving this differential equation we obtain a solution to the f(T gravity theories under certain conditions on the form of f(T and its first derivatives. Finally, we calculate the scalars of Riemann Christoffel tensor, Ricci tensor, Ricci scalar, torsion tensor, and its contraction to explain the singularities associated with this solution.

  5. Experimental Study of Axially Tension Cold Formed Steel Channel Members

    Science.gov (United States)

    Apriani, Widya; Lubis, Fadrizal; Angraini, Muthia

    2017-12-01

    Experimental testing is commonly used as one of the steps to determine the cause of the collapse of a building structure. The collapse of structures can be due to low quality materials. Although material samples have passed laboratory tests and the existing technical specifications have been met but there may be undetected defects and known material after failure. In this paper will be presented Experimental Testing of Axially Tension Cold Formed Steel Channel Members to determine the cause of the collapse of a building roof truss x in Pekanbaru. Test of tensile strength material cold formed channel sections was performed to obtain the main characteristics of Cold Formed steel material, namely ultimate tensile strength loads that can be held by members and the yield stress possessed by channel sections used in construction. Analysis of axially tension cold formed steel channel section presents in this paper was conducted through experimental study based on specificationsAnnualBook of ASTM Standards: Metal Test methods and Analitical Procedures, Section 3 (1991). The result of capacity loads experimental test was compared with design based on SNI 03-7971-2013standard of Indonesia for the design of cold formed steel structural members. The results of the yield stress of the material will be seen against the minimum allowable allowable stress range. After the test, the percentace of ultimate axial tension capacity theory has a result that is 16.46% larger than the ultimate axial tension capacity experimental. When compared with the load that must be borne 5.673 kN/m it can be concluded that 2 specimens do not meet. Yield stress of member has fulfilled requirement that wass bigger than 550 MPa. Based on the curve obtained ultimate axial tension capacity theory, results greater than experimental. The greatest voltage value (fu) is achieved under the same conditions as its yield stress. For this specimen with a melting voltage value fy = 571.5068 MPa has fulfilled the

  6. Design and axial optimization of nuclear fuel for BWR reactors; Diseno y optimizacion axial de combustible nuclear para reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Garcia V, M.A

    2006-07-01

    In the present thesis, the modifications made to the axial optimization system based on Tabu Search (BT) for the axial design of BWR fuel type are presented, developed previously in the Nuclear Engineering Group of the UNAM Engineering Faculty. With the modifications what is mainly looked is to consider the particular characteristics of the mechanical design of the GE12 fuel type, used at the moment in the Laguna Verde Nucleo electric Central (CNLV) and that it considers the fuel bars of partial longitude. The information obtained in this thesis will allow to plan nuclear fuel reloads with the best conditions to operate in a certain cycle guaranteeing a better yield and use in the fuel burnt, additionally people in charge in the reload planning will be favored with the changes carried out to the system for the design and axial optimization of nuclear fuel, which facilitate their handling and it reduces their execution time. This thesis this developed in five chapters that are understood in the following way in general: Chapter 1: It approaches the basic concepts of the nuclear energy, it describes the physical and chemical composition of the atoms as well as that of the uranium isotopes, the handling of the uranium isotope by means of the nuclear fission until arriving to the operation of the nuclear reactors. Chapter 2: The nuclear fuel cycle is described, the methods for its extraction, its conversion and its enrichment to arrive to the stages of the nuclear fuel management used in the reactors are described. Beginning by the radial design, the axial design and the core design of the nuclear reactor related with the fuel assemblies design. Chapter 3: the optimization methods of nuclear fuel previously used are exposed among those that are: the genetic algorithms method, the search methods based on heuristic rules and the application of the tabu search method, which was used for the development of this thesis. Chapter 4: In this part the used methodology to the

  7. Curvature aided efficient axial field emission from carbon nanofiber–reduced graphene oxide superstructures on tungsten wire substrate

    Energy Technology Data Exchange (ETDEWEB)

    Jha, Arunava [School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700032 (India); Roy, Rajarshi; Sen, Dipayan [Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032 (India); Chattopadhyay, Kalyan K., E-mail: kalyan_chattopadhyay@yahoo.com [School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700032 (India); Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032 (India)

    2016-03-15

    Graphical abstract: - Highlights: • Efficient axial field emitter was fabricated through deposition of thin RGO layer by Langmuir–Blodgett method. • Tungsten wire substrate was used. • The CNF–RGO superstructure produced better field emission characteristics compared to bare CNF. - Abstract: Field emission characteristics found in reduced graphene oxide (RGO) and RGO based composite systems have always been an area of research interest mainly due to presence of prolific quasi aligned edges working as emitter sites. However, the specific role and extent of edge curvature geometry in RGO systems in regards to the enhancement of field emission has not discussed thoroughly prior to this work. In this work we demonstrate enhanced axial field emission due to top assembly of thin RGO layer over a quasi-vertically aligned carbon nanofiber thin film supported on a tungsten wire substrate. Furthermore, simulation analysis for our RGO based hybrid system using finite element modeling showed that two-stage local field amplification in RGO is responsible for the overall improvement of field emission characteristics. In support of our findings, a tentative explanation has been proposed based on the additional emission from RGO edges in between the CNF network resulting to the enhancement of axial field emission in the nanocomposite superstructure.

  8. Effects of model axial-flow hydrokinetic turbines on scour and bedforms

    Science.gov (United States)

    Hill, C.; Musa, M.; Chamorro, L. P.; Guala, M.

    2013-12-01

    Laboratory experiments were performed in a straight flume (15m long x 0.9m wide) at the St. Anthony Falls Laboratory at the University of Minnesota to investigate local scour caused by 1:33 scale model axial-flow hydrokinetic turbines and their effects on bedform spatial and temporal variability. Spatio-temporal topography measurements provided the evolution of scour and deposition downstream of the turbine(s), including mean local bed deformation and migrating bedform characteristics (i.e. wavelength, amplitude and 2D vs. 3D geometry). Both single and aligned turbine configurations were operated under live bed conditions. Additionally, individual turbine foundation components were monitored for their contribution towards total scour and compared to standard bridge pier scour predictions. Results showed that in live bed experiments with relatively large bedforms migrating past the turbine(s), local scour depths and water surface fluctuations increased compared to those observed during clear water conditions. Potential field-scale deployment implications will be discussed.

  9. Local food:

    DEFF Research Database (Denmark)

    Sundbo, Donna Isabella Caroline

    2013-01-01

    Recently there has been more focus on food in general and local food in particular. But what is local food? And what are the perceptions of this concept according to theory and to providers and consumers of local food? This article first summarises and compares three different theoretical perspec...... the providers and consumers studied on what local food is. However, this may change in time.......Recently there has been more focus on food in general and local food in particular. But what is local food? And what are the perceptions of this concept according to theory and to providers and consumers of local food? This article first summarises and compares three different theoretical...... perspectives on local food, namely experience economy, local food systems and what is termed pro-industrialism. These have differing and sometimes opposite conceptualisations and aims for the concept of local food. Using the perspective of experience economy as theoretical background, the concept of local food...

  10. Renormalisation group flows for gauge theories in axial gauges

    CERN Document Server

    Litim, Daniel F; Litim, Daniel F.; Pawlowski, Jan M.

    2002-01-01

    Gauge theories in axial gauges are studied using Exact Renormalisation Group flows. We introduce a background field in the infrared regulator, but not in the gauge fixing, in contrast to the usual background field gauge. It is shown how heat-kernel methods can be used to obtain approximate solutions to the flow and the corresponding Ward identities. Expansion schemes are discussed, which are not applicable in covariant gauges. As an application, we derive the one-loop effective action for covariantly constant field strength, and the one-loop beta-function for arbitrary regulator.

  11. Test Procedure for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test procedure described in the following is used when examining the effects of static or cyclic loading on the skin friction of an axially loaded pile in dense sand. The pile specimen is only loaded in tension to avoid any contribution from the base resistance. The pile dimensions are chosen...... to resemble full scale dimension of piles used in offshore pile foundations today. In this report is given a detailed description of the soil preparation and pile installation procedures as well data acquisition methods....

  12. Axial currents, supercurrents and anomalies in supersymmetric QED

    Energy Technology Data Exchange (ETDEWEB)

    Clark, T.E.

    1979-01-01

    The currents associated with the superconformal symmetries are defined as moments of the supercurrent, V/sub ..mu... All of the current (non-) conservation equations are known once the generalized trace of the supercurrent, D/sup ..cap alpha../V/sub ..cap alpha cap alpha../, is found. The superconformal anomalies are shown to have coefficients given by ..beta.. of the Callan-Symanzik equation. In super QED there is an additional U(1) axial current whose anomaly has a coefficient with no radiative corrections. 5 references.

  13. Time Dependent and Steady Uni-axial Elongational Viscosity

    DEFF Research Database (Denmark)

    Nielsen, Jens K.; Rasmussen, Henrik Koblitz; Hassager, Ole

    2005-01-01

    Here we present measurements of transient and steady uni-axial elongational viscosity, using the Filament Stretching Rheometer1 or FSR1 (see Fig. 1) of the following melts: Four narrow MMD polystyrene (PS) samples with weight-average molar mass Mw in the range of 50k to 390k. Three different bi......-disperse samples, mixed from the narrow MMD PS. Two low-density polyethylene (LDPE) melts (Lupolen 1840D and 3020D). A steady-state viscosity was kept for 1-2.5 Hencky strain units in all measurements....

  14. Electromagnetic Reciprocal Cloak with Only Axial Material Parameter Spatially Variant

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2012-01-01

    Full Text Available Reciprocal cloak is an intriguing metamaterial device, in which a hidden antenna or a sensor can receive electromagnetic irradiation from the outside but its presence will not be detected. Based on transformation optics, a cylindrical electromagnetic reciprocal cloak with only axial parameter varying with radius is designed and validated by full wave simulation. When two dispersive reciprocal cloaks are put together, they do not interfere with each other. Our work demonstrates the electromagnetic compatibility (EMC ability of the reciprocal cloak which is very important in multi antenna and sensor design.

  15. Calibration and Reconstruction in Non-Central Axial Catadioptric Systems

    OpenAIRE

    Perdigoto, Luís Miguel Ramos

    2015-01-01

    Tese de doutoramento em Engenharia Electrotécnica e de Computadores, no ramo de Automação e Robótica, apresentada ao Departamento de Engenharia Eletrotécnica e de Computadores da Faculdade de Ciências e Tecnologia da Universidade de Coimbra Esta tese de doutoramento estuda sistemas de visão axiais catadióptricos nãocentrais, ou seja, sistemas com um espelho de simetria axial e uma câmara pinhole com o centro ótico pertencente ao eixo do espelho. São propostos métodos originais par...

  16. Plasticity around an Axial Surface Crack in a Cylindrical Shell

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    field in an axially cracked cylindrical shell arising from use of classical eighth order shallow shell theory is removed when use is made of a tenth order shell theory which accounts for transverse shear deformations. Although the membrane stresses are only moderately affected, the influence...... and Ratwani,3–5 it generalises Dugdale's assumption of a concentrated yield zone in the plane of the crack but, contrary to that model, transverse shear effects are included and a continuous stress distribution is assumed in the yield zone. The inherent difficulties arising from the use of shell theory...

  17. Human axial chromatic aberration found not to decline with age.

    Science.gov (United States)

    Ware, C

    1982-01-01

    Millodot (1976) reported a dramatic decline in the amount of axial chromatic aberration of the human eye with age. The present study represents a failure to replicate that finding using a more standard procedure. No difference in chromatic aberration was found between a young and an older group of observers. Also, the chromatic aberrations of two observers which had been measured 25 years previously showed no decline when these measurements were repeated, even though their ages at first and second testing straddled the period over which Millodot reported the most change in chromatic aberration.

  18. Dynamic Response of Axially Loaded Euler-Bernoulli Beams

    DEFF Research Database (Denmark)

    Bayat, M.; Barari, Amin; Shahidi, M.

    2011-01-01

    The current research deals with application of a new analytical technique called Energy Balance Method (EBM) for a nonlinear problem. Energy Balance Method is used to obtain the analytical solution for nonlinear vibration behavior of Euler-Bernoulli beams subjected to axial loads. Analytical...... expressions for geometrically nonlinear vibration of beams are provided. The effect of vibration amplitude on the nonlinear frequency is discussed. Comparison between Energy Balance Method results and those available in literature demonstrates the accuracy of this method. In Energy Balance Method contrary...

  19. Design of an instrumented model pile for axial cyclic loading

    OpenAIRE

    Rakotonindriana, Julio; Le Kouby, Alain; Buttigieg, Stéphane; Derkx, François; Thorel, Luc; Garnier, Jacques

    2010-01-01

    To study the behavior of a pile foundation under a cyclic axial loading, an instrumented pile was developed for centrifuge tests. The design of the instrumented pile takes into account some constraints due to centrifuge tests and allows us to install the pile in flight. The instrumentation of the pile permits the measure of the skin friction at five depths and the tip resistance. Some static and cyclic tests have been made and show the efficiency of the instrumented pile in capturing the main...

  20. Tunable axial potentials for atom-chip waveguides

    Science.gov (United States)

    Stickney, James A.; Imhof, Eric; Kasch, Brian; Kroese, Bethany; Crow, Jonathon A. R.; Olson, Spencer E.; Squires, Matthew B.

    2017-11-01

    We present a method for generating precise, dynamically tunable magnetic potentials that can be described by a polynomial series along the axis of a cold-atom waveguide near the surface of an atom chip. With a single chip design consisting of several wire pairs, various axial potentials can be created by changing the ratio of the currents in the wires, including double wells, triple wells, and pure harmonic traps with suppression of higher-order terms. We use this method to design and fabricate a chip with modest experimental requirements. Finally, we use the chip to demonstrate a double-well potential.

  1. Discrimination of hydrogen-bonded complexes with axial chirality

    Science.gov (United States)

    Alkorta, Ibon; Elguero, José

    2002-10-01

    The chiral self-discrimination of twelve molecules showing axial chirality has been studied. They included peroxides, hydrazines, carboxylic acids, amides, and allenes. The homo and heterochiral dimers of the selected compounds, that present two hydrogen bonds, have been studied by means of density functional theory (B3LYP/6-31+G**) and ab initio (MP2/6-31+G** and MP2/6-311++G**) methods. The energetic differences found for the complexes of each compound have been rationalized based on their electron density maps and the natural bond orbital analysis. In some cases, intermolecular oxygen-oxygen interactions have been found and interpreted as additional stabilizing contacts.

  2. Axial dispersion via shear-enhanced diffusion in colloidal suspensions

    KAUST Repository

    Griffiths, I. M.

    2012-03-01

    The familiar example of Taylor dispersion of molecular solutes is extended to describe colloidal suspensions, where the fluctuations that contribute to dispersion arise from hydrodynamic interactions. The generic scheme is illustrated for a suspension of particles in a pressure-driven pipe flow, with a concentration-dependent diffusivity that captures both the shear-induced and Brownian contributions. The effect of the cross-stream migration via shear-induced diffusion is shown to dramatically reduce the axial dispersion predicted by classical Taylor dispersion for a molecular solute. Analytic and numerical solutions are presented that illustrate the effect of the concentration dependence of this nonlinear hydrodynamic mechanism. Copyright © EPLA, 2012.

  3. SUSY approach to Pauli Hamiltonians with an axial symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Ioffe, M V; Kuru, S; Negro, J; Nieto, L M [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, 47071 Valladolid (Spain)

    2006-06-02

    A two-dimensional Pauli Hamiltonian describing the interaction of a neutral spin-1/2 particle with a magnetic field having axial and second-order symmetries is considered. After separation of variables, the one-dimensional matrix Hamiltonian is analysed from the point of view of supersymmetric quantum mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and also to the Hamiltonian hierarchies generated by intertwining operators. The spectrum is studied by means of the associated matrix shape invariance. The relation between the intertwining operators and the second-order symmetries is established, and the full set of ladder operators that complete the dynamical algebra is constructed.

  4. Remotely scanned multiphoton temporal focusing by axial grism scanning.

    Science.gov (United States)

    Dana, Hod; Shoham, Shy

    2012-07-15

    A simple technique for remote scanning of the focal plane in temporal focusing multiphoton microscopy is demonstrated both theoretically and experimentally. A new on-axis light propagation optical setup design enables this scanning, which was considered not feasible in previous studies. The focal plane is axially displaced by the movement of a remote optical device, consisting of a double prism grating, and optionally a cylindrical lens. The displacement is linear, and its slope is inversely proportional to the square of the optical system's magnification.

  5. Design Of A Throw-In Axial Flow Rice Thresher Fitted With Peg And Screw Threshing Mechanism

    OpenAIRE

    Ahorbo, Gerald K.

    2015-01-01

    The research seeks to design a motorized rice thresher that can be manufactured by local artisans and accessed by all small-holder rice farmers. The concept of the thresher emanated from the working principles of a throw-in axial flow thresher a peg type threshing mechanism and a screw type threshing mechanism. Components of the thresher were designed and a prototype was made.The power requirement of the thresher was evaluated and validated with the power thresher standards of the Institute o...

  6. Research on a novel axial-flux magnetic-field-modulated brushless double-rotor machine with low axial force and high efficiency

    Directory of Open Access Journals (Sweden)

    Chengde Tong

    2017-05-01

    Full Text Available The axial-flux magnetic-field-modulated brushless double-rotor machine (MFM-BDRM is a possible alternative as a power-split device for hybrid electric vehicles (HEVs. However, the existence of large axial force may lead to assembly problems and rich inner air-gap harmonics could result in high PM loss and low efficiency. This paper proposes a novel axial-flux MFM-BDRM with improved PM rotor structure. 2-D analytical method to predict the magnetic-field distribution of the proposed MFM-BDRM is developed and the design procedure of the proposed machine is illustrated. The impact of key geometrical parameters on axial force and torque is investigated. To evaluate the advantage of the proposed machine, a comparison is made with a conventional one with respect to electromagnetic performances. Results show that the proposed machine is effective in reducing PM eddy loss and axial force by 60% and 35%, respectively.

  7. Research on a novel axial-flux magnetic-field-modulated brushless double-rotor machine with low axial force and high efficiency

    Science.gov (United States)

    Tong, Chengde; Song, Zhiyi; Bai, Jingang; Liu, Jiaqi; Zheng, Ping

    2017-05-01

    The axial-flux magnetic-field-modulated brushless double-rotor machine (MFM-BDRM) is a possible alternative as a power-split device for hybrid electric vehicles (HEVs). However, the existence of large axial force may lead to assembly problems and rich inner air-gap harmonics could result in high PM loss and low efficiency. This paper proposes a novel axial-flux MFM-BDRM with improved PM rotor structure. 2-D analytical method to predict the magnetic-field distribution of the proposed MFM-BDRM is developed and the design procedure of the proposed machine is illustrated. The impact of key geometrical parameters on axial force and torque is investigated. To evaluate the advantage of the proposed machine, a comparison is made with a conventional one with respect to electromagnetic performances. Results show that the proposed machine is effective in reducing PM eddy loss and axial force by 60% and 35%, respectively.

  8. The effects of initial rise and axial loads on MEMS arches

    KAUST Repository

    Tella, Sherif Adekunle

    2017-04-07

    Arch microbeams have been utilized and proposed for many uses over the past few years due to their large tunability and bistability. However, recent experimental data have shown different mechanical behavior of arches when subjected to axial loads. This paper aims to investigate in depth the influence of the competing effects of initial rise and axial loads on the mechanical behavior of micromachined arches; mainly their static deflection and resonant frequencies. Based on analytical solutions, the static response and eigenvalue problems are analyzed for various values of initial rises and axial loads. Universal curves showing the variation of the first three resonance frequencies of the arch are generated for various values of initial rise under both tensile and compressive axial loads. This study shows that increasing the tensile or compressive axial loads for different values of initial rise may lead to either increase in the stiffness of the beam or initial decrease in the stiffness, which later increases as the axial load is increased depending on the dominant effect of the initial rise of the arch and the axial load. The obtained universal curves represent useful design tools to predict the tunability of arches under axial loads for various values of initial rises. The use of the universal curves is demonstrated with an experimental case study. Analytical formulation is developed to predict the point of minimum where the trend of the resonance frequency versus axial loads changes qualitatively due to the competing effects of axial loads and initial curvature.

  9. Axial length of atomic bomb survivors in Nagasaki

    Energy Technology Data Exchange (ETDEWEB)

    Wakiyama, Harumi; Kishikawa, Yasuhiro; Imamura, Naoki [Nagasaki Atomic Bomb Hospital (Japan); Amemiya, Tsugio [Nagasaki Univ. (Japan). School of Medicine

    2002-03-01

    We reviewed a series of 778 patients who had cataract surgery during the past 4 years at the Nagasaki Atomic Bomb Memorial Hospital. We evaluated the history of exposure to radiation by atomic bomb in 1945, axial length and state of refraction. All were born before 1945. The series comprised 263 males and 515 females. Their ages averaged 76.5{+-}8.6 years. History of exposure to radiation was present in 356 patients. The remaining 422 patients served as control. There was no difference in the type of cataract between the two groups. High myopia was present in 11 irradiated patients (3.2%) and in 24 patients in the control group (6.0%). The difference was not significant (p=0.083). There was no high myopia among 24 patients who were aged 18 years or less at the time of radiation and who were within 2 km from the epicenter. No difference was present regarding the axial length between the two groups or between both sexes. The present result is not definitive because ''irradiated group'' would include those with little or no exposure and because precise data has not been available about the dosis of radiation. (author)

  10. Characteristics of the Swirling Flow Generated by an Axial Swirler

    Science.gov (United States)

    Fu, Yongqiang; Jeng, San-Mou; Tacina, Robert

    2005-01-01

    An experimental investigation was conducted to study the aerodynamic characteristics of the confined, non-reacting, swirling flow field. The flow was generated by a helicoidal axial-vaned swirler with a short internal convergent-divergent venturi, which was confined within 2-inch square test section. A series of helicoidal axial-vaned swirlers have been designed with tip vane angles of 40 deg., 45 deg., 50 deg., 55 deg., 60 deg. and 65 deg.. The swirler with the tip vane angle of 60 deg. was combined with several simulated fuel nozzle insertions of varying lengths. A two-component Laser Doppler Velocimetry (LDV) system was employed to measure the three-component mean velocities and Reynolds stresses. Detailed data are provided to enhance understanding swirling flow with different swirl degrees and geometries and to support the development of more accurate physicaVnumerica1 models. The data indicated that the degree of swirl had a clear impact on the mean and turbulent flow fields. The swirling flow fields changed significantly with the addition of a variety of simulated fuel nozzle insertion lengths

  11. Axial Instability Growth in Tungsten Wire Array Z-Pinches

    Science.gov (United States)

    Cahill, Adam; Knapp, Patrick; Greenly, John; Pikuz, Sergei; Shelkovenko, Tania; Hammer, David

    2010-11-01

    The individual exploding wires in wire array z-pinches have been shown to suffer from axially non-uniformity beginning from the moment of plasma formation. This non-uniformity grows in amplitude and wavelength until it reaches what appears to be a material dependent wavelength at the time array implosion begins. Previous work by Knapp et al. [1] studied the temporal evolution of this instability in aluminum wire arrays. We have extended that work to include the evolution of tungsten wire array instabilities. Time gated laser shadowgraphy is used to track wavelength and amplitude over a series of shots to develop a record of the instability's growth. We attempt to identify array parameters which significantly contribute to the growth of this instability. [4pt] [1] Knapp, P. F., J. B. Greenly, P. A. Gourdain, C. L. Hoyt, M. R. Martin, S. A. Pikuz, C. E. Seyler, T. A. Shelkovenko, and D. A. Hammer. ``Growth and Saturation of the Axial Instability in Low Wire Number Wire Array Z Pinches.'' Physics of Plasmas 17 (2010). Web.

  12. Pit above the lesser tuberosity in axial view radiography.

    Science.gov (United States)

    Cho, Jae-Ho; Han, Kyeong-Jin; Lee, Doo-Hyung; Chung, Nam-Su; Park, Do Young

    2015-02-01

    This study examined the relationship between the presence of a pit above the lesser tuberosity on axial view radiographs and rotator cuff tears and compared the demographic data between groups according to the presence of a pit above the lesser tuberosity. The hypothesis of this study was that the radiographic finding of a pit above the lesser tuberosity is related to rotator cuff tears. For 112 patients with a symptomatic rotator cuff tear, plain radiographs of the symptomatic shoulder (tear side radiographs) and plain radiographs of the asymptomatic contralateral shoulder (no-tear side radiographs) were assessed. Seventeen radiological findings, including a pit above the lesser tuberosity, osteophytes, subchondral cysts, and sclerosis, were recorded by one blinded observer. Demographic data such as age, duration of symptoms, sex, arm dominance, smoking history, trauma history, American Shoulder and Elbow Surgeons score, Constant score, and involved tendon were collected. A pit above the lesser tuberosity was noted on tear side radiographs of 40 patients (35.7 %) and on the no-tear side radiographs of 27 patients (24.1 %), representing a significant difference (P = 0.040). A pit associated with a rotator cuff tear was observed more often in the dominant arm (P = 0.040) and more often in patients with less previous trauma (P = 0.024). A pit above the lesser tuberosity on axial view radiography was associated with a rotator cuff tear and occurred more often in the dominant arm of patients who had no trauma history. Prognostic study, Level III.

  13. Regularities of axially-periodical magnetic field of a betatron

    Energy Technology Data Exchange (ETDEWEB)

    Zvontsov, A.A.; Filinova, V.A.; Chakhlov, V.L. (Tomskij Politekhnicheskij Inst. (USSR). Nauchno-Issledovatel' skij Inst. Ehlektronnoj Introskopii)

    1983-07-01

    Consideration is being given to the possibility of increasing the stability region of particle motion in a betatron with an axially-periodic magnetic field. The damping of radial betatron oscillations is accomplished by variation of the index guiding magnetic field drop-off according to z-coordinate and the instability effect is reduced by the beam separation when separate beams, are being accelerated in ''proper'' equilibrium orbits, organized in parallel z-planes. It is shown on the base of solution of the equation for vector potential of magnetic field that under certain conditions focusing properties of betatron magnetic field have spacing character according to z-coordinate. The expression for the determination of the distance between equilibrium orbit planes for the given orbit radius and the of field drop-off was obtained. Peculiarities of operation of such accelerator were described. Betatrons with axially-periodic guiding field can generate one intense pulse of radiation or several pulses of lower density with regulated time intervals between them and can be used, for example, for film-roentgenography of rapid processes.

  14. Axial Ge/Si nanowire heterostructure tunnel FETs.

    Energy Technology Data Exchange (ETDEWEB)

    Dayeh, Shadi A. (Los Alamos National Laboratory); Gin, Aaron V.; Huang, Jian Yu; Picraux, Samuel Thomas (Los Alamos National Laboratory)

    2010-03-01

    Axial Ge/Si heterostructure nanowires (NWs) allow energy band-edge engineering along the axis of the NW, which is the charge transport direction, and the realization of asymmetric devices for novel device architectures. This work reports on two significant advances in the area of heterostructure NWs and tunnel FETs: (i) the realization of 100% compositionally modulated Si/Ge axial heterostructure NWs with lengths suitable for device fabrication and (ii) the design and implementation of Schottky barrier tunnel FETs on these NWs for high-on currents and suppressed ambipolar behavior. Initial prototype devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a very high current drive in excess of 100 {micro}A/{micro}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios. Prior work on the synthesis of Ge/Si axial NW heterostructures through the VLS mechanism have resulted in axial Si/Si{sub 1-x}Ge{sub x} NW heterostructures with x{sub max} {approx} 0.3, and more recently 100% composition modulation was achieved with a solid growth catalyst. In this latter case, the thickness of the heterostructure cannot exceed few atomic layers due to the slow axial growth rate and concurrent radial deposition on the NW sidewalls leading to a mixture of axial and radial deposition, which imposes a big challenge for fabricating useful devices form these NWs in the near future. Here, we report the VLS growth of 100% doping and composition modulated axial Ge/Si heterostructure NWs with lengths appropriate for device fabrication by devising a growth procedure that eliminates Au diffusion on the NW sidewalls and minimizes random kinking in the heterostructure NWs as deduced from detailed microscopy analysis. Fig. 1 a shows a cross-sectional SEM image of epitaxial Ge/Si axial NW heterostructures grown on a Ge(111) surface. The interface abruptness in these Ge/Si heterostructure NWs is of the order of the NW diameter. Some of these NWs develop a crystallographic kink that is {approx

  15. Three-axial Fiber Bragg Grating Strain Sensor for Volcano Monitoring

    Science.gov (United States)

    Giacomelli, Umberto; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvatore; Maccioni, Enrico; Morganti, Mauro; Orazi, Massimo; Peluso, Rosario; Sorrentino, Fiodor

    2017-04-01

    Fiber optic and FBGs sensors have attained a large diffusion in the last years as cost-effective monitoring and diagnostic devices in civil engineering. However, in spite of their potential impact, these instruments have found very limited application in geophysics. In order to study earthquakes and volcanoes, the measurement of crustal deformation is of crucial importance. Stress and strain behaviour is among the best indicators of changes in the activity of volcanoes .. Deep bore-hole dilatometers and strainmeters have been employed for volcano monitoring. These instruments are very sensitive and reliable, but are not cost-effective and their installation requires a large effort. Fiber optic based devices offer low cost, small size, wide frequency band, easier deployment and even the possibility of creating a local network with several sensors linked in an array. We present the realization, installation and first results of a shallow-borehole (8,5 meters depth) three-axial Fiber Bragg Grating (FBG) strain sensor prototype. This sensor has been developed in the framework of the MED-SUV project and installed on Etna volcano, in the facilities of the Serra La Nave astrophysical observatory. The installation siteis about 7 Km South-West of the summit craters, at an elevation of about 1740 m. The main goal of our work is the realization of a three-axial device having a high resolution and accuracy in static and dynamic strain measurements, with special attention to the trade-off among resolution, cost and power consumption. The sensor structure and its read-out system are innovative and offer practical advantages in comparison with traditional strain meters. Here we present data collected during the first five months of operation. In particular, the very clear signals recorded in the occurrence of the Central Italy seismic event of October 30th demonstrate the performances of our device.

  16. Interconnection between several eye biomechanical and biometric parameters in children with axial and refractive mild myopia

    Directory of Open Access Journals (Sweden)

    T. Ye. Tsybulskaya

    2016-08-01

    Full Text Available Aim – to study the relationship of biometric and biomechanical indicators of corneoscleral capsule of the eye in children with axial and refractive mild myopia. Materials and methods. Axial myopia was diagnosed in 32 children (64 eyes, refractive myopia – 18 (36 eyes. The control group – 16 children without ophthalmic diseases (32 eyes. Eye examination: visometry, automated refractometry, biomicroscopy, ophthalmoscopy, determination of the axial length of the eyeball and corneal hysteresis. Results. Significant differences were determined in the indicators of dioptric power of the cornea: 42.2 dpt in patients with axial and 44.7 dpt with refractive myopia (p<0.05, and also difference between patients with refractive myopia and the control group, in which the diopter power of cornea was 42.6 (p<0.05. There are also significant differences in the indicators of the axial length of eyes between axial and refractive myopia – 24.5±0.64 mm and 23.1±0.43 mm (p<0.05. Significant difference with the control group in the axial length marked only in eyes with axial myopia 22.7±0.33 mm and 24.5±0.64 mm, respectively (p<0.05. Corneal hysteresis determined significantly reduced on eyes with both the axial and refractive myopia, which was significantly lower than in the indicators of emmetropic eyes of the control group 13.7 (p<0.05. Corneal hysteresis is inversely related to the axial length of the eyeball: in patients with axial myopia r -0.32, p<0.05; with refractive myopia r -0.36, p<0.05. Сorrelation between diopter power of cornea and axial length of the eyeball: r -0.53, р<0.05 in eyes with axial myopia and r -0.42, p<0.05 refractive myopia. Comparative analysis showed no significant differences between the corneal hysteresis, the axial length of the eye and the spherical component of myopia. Conclusions. In patients with axial and refractive mild myopia corneal hysteresis is reduced on average in 1.2 and 1.1 times, in comparison with

  17. Cyclic Axial-Torsional Deformation Behavior of a Cobalt-Base Superalloy

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1995-01-01

    The cyclic, high-temperature deformation behavior of a wrought cobalt-base super-alloy, Haynes 188, is investigated under combined axial and torsional loads. This is accomplished through the examination of hysteresis loops generated from a biaxial fatigue test program. A high-temperature axial, torsional, and combined axial-torsional fatigue database has been generated on Haynes 188 at 760 C. Cyclic loading tests have been conducted on uniform gage section tubular specimens in a servohydraulic axial-torsional test rig. Test control and data acquisition were accomplished with a minicomputer. The fatigue behavior of Haynes 188 at 760 C under axial, torsional, and combined axial-torsional loads and the monotonic and cyclic deformation behaviors under axial and torsional loads have been previously reported. In this paper, the cyclic hardening characteristics and typical hysteresis loops in the axial stress versus axial strain, shear stress ,versus engineering shear strain, axial strain versus engineering shear strain. and axial stress versus shear stress spaces are presented for cyclic in-phase and out-of-phase axial-torsional tests. For in-phase tests, three different values of the proportionality constant lambda (the ratio of engineering shear strain amplitude to axial strain amplitude, are examined, viz. 0.86, 1.73, and 3.46. In the out-of-phase tests, three different values of the phase angle, phi (between the axial and engineering shear strain waveforms), are studied, viz., 30, 60, and 90 degrees with lambda equals 1.73. The cyclic hardening behaviors of all the tests conducted on Haynes 188 at 760 C are evaluated using the von Mises equivalent stress-strain and the maximum shear stress-maximum engineering shear strain (Tresca) curves. Comparisons are also made between the hardening behaviors of cyclic axial, torsional, and combined in-phase (lambda = 1.73 and phi = 0) and out-of-phase (lambda = 1.73 and phi = 90') axial-torsional fatigue tests. These comparisons

  18. Axial design of fuel for BWRs using neural networks; Diseno axial de combustible para BWRs usando redes neuronales

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, J.J.; Castillo, A.; Montes, J.L.; Perusquia, R. [ININ, Carretera Mexico-Toluca s/n, 52750 La Marquesa, Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: jjortiz@nuclear.inin.mx

    2007-07-01

    In this work a new system of axial optimization of fuel is presented based on a recurrent multi state neural net called RENODC. They are described with detail the main characteristics of this type of neural net (architecture, energy function and actualization of neural states) and like was adapted to the assemble design of nuclear fuel. The fuel design is proven by means of a fuel recharge and pre determined control rod patterns. By this way a good axial fuel design one has, when the thermal limits are fulfilled along the cycle, the reactor stays critic and at least the wanted longitude of the cycle is reached; also the margin of in cold turned off is verified. The assemble of fuel created with RENODC it is substituted by a recharge assemble and it is sought to verify that the energy requirements and aspects of safety are completed. The used cycle corresponds to a balance cycle of 18 months that it can be applied to the Laguna Verde Nucleo electric Central. The tests demonstrate the effectiveness of the system to reach satisfactory results in times of CPU of around 4 hours. This way, it could be proven that the design proposed with a lightly superior enrichment to that of the substituted design, fulfills the energy requirements. In later stages of this project this system will be coupled to the other optimization modules that are already had. (Author)

  19. Hydrodynamics and sediment transport in a meandering channel with a model axial-flow hydrokinetic turbine

    Science.gov (United States)

    Hill, Craig; Kozarek, Jessica; Sotiropoulos, Fotis; Guala, Michele

    2016-02-01

    An investigation into the interactions between a model axial-flow hydrokinetic turbine (rotor diameter, dT = 0.15 m) and the complex hydrodynamics and sediment transport processes within a meandering channel was carried out in the Outdoor StreamLab research facility at the University of Minnesota St. Anthony Falls Laboratory. This field-scale meandering stream with bulk flow and sediment discharge control provided a location for high spatiotemporally resolved measurements of bed and water surface elevations around the model turbine. The device was installed within an asymmetric, erodible channel cross section under migrating bed form and fixed outer bank conditions. A comparative analysis between velocity and topographic measurements, with and without the turbine installed, highlights the local and nonlocal features of the turbine-induced scour and deposition patterns. In particular, it shows how the cross-section geometry changes, how the bed form characteristics are altered, and how the mean flow field is distorted both upstream and downstream of the turbine. We further compare and discuss how current energy conversion deployments in meander regions would result in different interactions between the turbine operation and the local and nonlocal bathymetry compared to straight channels.

  20. Tilted versus axially placed dental implants: a meta-analysis.

    Science.gov (United States)

    Chrcanovic, Bruno Ramos; Albrektsson, Tomas; Wennerberg, Ann

    2015-02-01

    The purpose of the present review was to test the null hypothesis of no difference in the implant failure rate, marginal bone loss, and postoperative infection for patients being rehabilitated by tilted or by axially placed dental implants, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in July 2014. Eligibility criteria included clinical human studies, either randomised or not, interventional or observational. The estimates of an intervention were expressed in risk ratio (RR) and mean difference (MD) in millimetres. The search strategy resulted in 44 publications. A total of 5029 dental implants were tilted (82 failures; 1.63%), and 5732 implants were axially placed (104 failures; 1.81%). The difference between the procedures did not significantly affect the implant failure rates (P=0.40), with a RR of 1.14 (95% CI 0.84-1.56). A statistically significant difference was found for implant failures when studies evaluating implants inserted in maxillae only were pooled (RR 1.70, 95% CI 1.05-2.74; P=0.03), the same not happening for the mandible (RR 0.77, 95% CI 0.39-1.52; P=0.45). There were no apparent significant effects of tilted dental implants on the occurrence of marginal bone loss (MD 0.03, 95% CI -0.03 to 0.08; P=0.32). Due to lack of satisfactory information, meta-analysis for the outcome 'postoperative infection' was not performed. It is suggested that the differences in angulation of dental implants might not affect the implant survival or the marginal bone loss. The reliability and validity of the data collected and the potential for biases and confounding factors are some of the shortcomings of the present study. The question whether tilted implants are more at risk for failure than axially placed implants has received increasing attention in the last years. As the philosophies of treatment alter over time, a periodic review of the different concepts is necessary to refine

  1. Predictors of Persistent Axial Neck Pain After Cervical Laminoplasty.

    Science.gov (United States)

    Kimura, Atsushi; Shiraishi, Yasuyuki; Inoue, Hirokazu; Endo, Teruaki; Takeshita, Katsushi

    2017-06-06

    Retrospective analysis of prospective data OBJECTIVE.: The aim of this study was to reveal baseline predictors of persistent post-laminoplasty neck pain. Axial neck pain is one of the most common complications after cervical laminoplasty; however, baseline predictors of persistent post-laminoplasty neck pain are unclear. We analyzed data from 156 patients who completed a 2-year follow-up after double-door laminoplasty for degenerative cervical myelopathy (DCM). Patients rated the average intensity of axial neck pain in the last month using an 11-point numerical rating scale (NRS) preoperatively and at the 2-year follow-up. The dependent variable was the presence of moderate-to-severe neck pain (NRS ≥4) at the 2-year follow-up. The independent variables included patient characteristics, baseline radiological parameters, surgical variables, baseline axial neck pain intensity, and baseline functions, which were measured by the Japanese Orthopaedic Association (JOA) score and the Short Form-36 survey (SF-36). Logistic regression analysis was performed to identify independent predictors of moderate-to-severe neck pain after laminoplasty. At the 2-year follow-up, 51 patients (32%) had moderate-to-severe neck pain, and 106 patients (68%) had no or mild pain. Univariate analysis revealed that the ratio of cervical anterolisthesis, ratio of current smoking, baseline neck pain intensity, and baseline SF-36 mental component summary (MCS) differed significantly between the groups. Multivariate logistic regression analysis showed that independent predictors of moderate-to-severe neck pain at the 2-year follow-up include the presence of anterolisthesis, current smoking, moderate-to-severe baseline neck pain, and lower SF-36 MCS. The presence of anterolisthesis and moderate-to-severe baseline neck pain were also associated with significantly poorer physical function after surgery. The presence of anterolisthesis was associated not only with the highest odds ratio of persistent

  2. Spine and axial skeleton injuries in the National Football League.

    Science.gov (United States)

    Mall, Nathan A; Buchowski, Jacob; Zebala, Lukas; Brophy, Robert H; Wright, Rick W; Matava, Matthew J

    2012-08-01

    The majority of previous literature focusing on spinal injuries in American football players is centered around catastrophic injuries; however, this may underestimate the true number of these injuries in this athletic cohort. The goals of this study were to (1) report the incidence of spinal and axial skeleton injuries, both minor and severe, in the National Football League (NFL) over an 11-year period; (2) determine the incidence of spinal injury by injury type, anatomic location, player position, mechanism of injury, and type of exposure (practice vs game); and (3) determine the average number of practices and days missed because of injury for each injury type. Descriptive epidemiological study. All documented injuries to the cervical, thoracic, and lumbar spine; pelvis; ribs; and spinal cord were retrospectively analyzed using the NFL's injury surveillance database over a period of 11 seasons from 2000 through 2010. The data were analyzed by the number of injuries per athlete-exposure, the anatomic location and type of injury, player position, mechanism of injury, and number of days missed per injury. A total of 2208 injuries occurred to the spine or axial skeleton over an 11-season interval in the NFL, with a mean loss of 25.7 days per injury. This represented 7% of the total injuries during this time period. Of these 2208 injuries, 987 (44.7%) occurred in the cervical spine. Time missed from play was greatest for thoracic disc herniations (189 days/injury). Other injuries that had a mean time missed greater than 30 days included (in descending order) cervical fracture (120 days/injury), cervical disc degeneration/herniation (85 days/injury), spinal cord injury (77 days/injury), lumbar disc degeneration/herniation (52 days/injury), thoracic fracture (34 days/injury), and thoracic nerve injury (30 days/injury). Offensive linemen were the most likely to suffer a spinal injury, followed by defensive backs, defensive linemen, and linebackers. Blocking and tackling

  3. Effect of flow oscillations on axial energy transport in a porous material

    Science.gov (United States)

    Siegel, R.

    1987-01-01

    The effects of flow oscillations on axial energy diffusion in a porous medium, in which the flow is continuously disrupted by the irregularities of the porous structure, are analyzed. The formulation employs an internal heat transfer coefficient that couples the fluid and solid temperatures. The final relationship shows that the axial energy transport per unit cross-sectional area and time is directly proportional to the axial temperature gradient and the square of the maximum fluid displacement.

  4. Sum rule analysis of vector and axial-vector spectral functions with excited states in vacuum

    OpenAIRE

    Hohler, Paul M.; Rapp, Ralf

    2012-01-01

    We simultaneously analyze vector and axial-vector spectral functions in vacuum using hadronic models constrained by experimental data and the requirement that Weinberg-type sum rules are satisfied. Upon explicit inclusion of an excited vector state, viz. rho', and the requirement that the perturbative continua are degenerate in vector and axial-vector channels, we deduce the existence of an excited axial-vector resonance state, a1', in order that the Weinberg sum rules are satisfied. The resu...

  5. Local Content

    CSIR Research Space (South Africa)

    Gibberd, Jeremy

    2016-10-01

    Full Text Available is also delineated in order to demonstrate the implications of local content on building design, construction and operation. The advantages and disadvantages of local content approaches are discussed and illustrated through examples. Finally, broad...

  6. Simulations of axial B-dot monitors inside a groove in the beam pipe

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiaozhong, E-mail: hexiaozhong@tsinghua.org.cn [Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang, Sichuan (China); Pang, Jian; Li, Qin [Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang, Sichuan (China); Du, Yingchao [Department of Engineering Physics, Tsinghua University, Beijing (China)

    2013-11-21

    Beam tilt measurement is important for understanding the beam dynamics. Our previous theoretical studies and simulations have shown that the axial B-dot in smooth beam pipe can be used to measure the beam tilt directly. Practical azimuthal B-dot loops typically are placed inside a groove in the beam pipe to avoid direct beam interception. For the same purpose, practical axial B-dot loops should also be placed inside such a groove. In this paper, responses of axial magnetic field to the beam tilt and to the beam offset, in the presence of the groove, are investigated by simulations. The simulation results show that the axial magnetic field in the central plane of the groove is proportional to the beam tilt and independent on the centroid position. The ratio between the axial magnetic field and the beam tilt depends on the position of the axial B-dot loop and the dimensions of the groove. -- Highlights: •MAFIA simulations were carried out to analyze the influence of recessed groove to axial B dots. •It is found that axial B dots still works in the central plane of the recessed groove. •The dimensions of the groove greatly influence the signal strength of axial B dots. •Results can be used for future optimizations.

  7. Axial traction magnetic resonance imaging (MRI) of the glenohumeral joint in healthy volunteers: initial experience.

    Science.gov (United States)

    Garwood, Elisabeth R; Souza, Richard B; Zhang, Amy; Zhang, Alan L; Ma, C Benjamin; Link, Thomas M; Motamedi, Daria

    Evaluate technical feasibility and potential applications of glenohumeral (GH) joint axial traction magnetic resonance imaging (MRI) in healthy volunteers. Eleven shoulders were imaged in neutral and with 4kg axial traction at 3T. Quantitative measurements were assessed. Axial traction was well tolerated. There was statistically significant widening of the superior GH joint space (p=0.002) and acromial angle (p=0.017) with traction. Inter-rater agreement was high. GH joint axial traction MRI is technically feasible and well tolerated in volunteers. Traction of the capsule, widening of the superior GH joint space and acromial angle were observed. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Significance of axial length monitoring in children with congenital cataract and update of measurement methods.

    Science.gov (United States)

    Zhan, Jiao; Lin, Haotian; Zhang, Xinyu; Chen, Weirong; Liu, Yizhi

    2013-06-01

    Congenital cataract is the main cause of blindness in children, with significantly varying treatment effects. The development of axial length is an important factor that affects the prognosis of these children. However, when compared with the eyes of normal children, the mechanism of growth of the axial length is so complicated that the reported findings differ significantly in terms of the measuring apparatus, assessment methods, and statistical outcome, making the rule of axial length development still unclear. In this paper, we first review the process of axial length development in normal healthy children and compare different hypotheses about certain factors that could affect the development of axial length. The results of some current research about the characteristics of axial length development in congenital cataract children are then reviewed. Lastly, the advantages and disadvantages of current axial length measurements methods are compared and analyzed. The purpose of this review is to improve our understanding of the complexity and importance of axial length development and to suggest better use of axial length monitoring measurements in congenital cataract children for pediatric ophthalmologists, with the hope of offering assistance that will enhance long-term therapeutic effects for these children.

  9. Coupled high Q-factor Surface Nanoscale Axial Photonics (SNAP) microresonators

    CERN Document Server

    Sumetsky, M; DiGiovanni, D J; Dulashko, Y; Fini, J M; Monberg, E

    2011-01-01

    We experimentally demonstrate series of identical two, three, and five coupled high Q-factor Surface Nanoscale Axial Photonics (SNAP) microresonators formed by periodic nanoscale variation of the optical fiber radius. These microresonators are fabricated with a 100 \\mum period along an 18 \\mum radius optical fiber. The axial FWHM of these microresonators is 80 \\mum and their Q-factor exceeds 107. In addition, we demonstrate a SNAP microresonator with the axial FWHM as small as 30 \\mum and the axial FWHM of the fundamental mode as small as 10 \\mum. These results may potentially enable the dense integration of record low loss coupled photonic microdevices on the optical fiber platform.

  10. Frontal chromatography of proteins. Effect of axial dispersion on column performance.

    Science.gov (United States)

    Heeter, G A; Liapis, A I

    1998-02-13

    A mathematical model describing the dynamic adsorption of proteins in columns packed with spherical porous adsorbent particles is used to study the effect of axial dispersion on the performance of chromatographic systems. The values of the axial dispersion coefficient, DL, are estimated from a correlation based on a model describing axial dispersion in packed beds that provides satisfactory results when compared with experiment. Simulations of frontal chromatography in systems including axial dispersion and in systems without axial dispersion are made and compared to determine the effect of axial dispersion on the efficiency of the adsorption process; also, the system parameters that influence axial dispersion are examined. It is found that the reduction in the efficiency of the adsorption process due to axial dispersion is small (< 1%) for columns of length 10 cm or greater. However, for short columns, this efficiency reduction can be as large as 10%. Increasing the adsorbent particle diameter, dp, increases the magnitude of the reduction in efficiency due to axial dispersion; the effect of increasing the adsorbent particle diameter, dp, is much more pronounced in a short column than in a long column.

  11. Local complications

    NARCIS (Netherlands)

    van den Akker, H.P.; Baart, J.A.; Baart, J.A.; Brand, H.S.

    2017-01-01

    Local anaesthesia is frequently used in dentistry and seldom leads to serious local complications. Nevertheless, it is of great importance to be aware of the causes of each local complication and – if necessary – implement correct treatment. The patient must be informed extensively and, if

  12. A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

    CERN Document Server

    Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

    1997-01-01

    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

  13. Electric field generated by axial longitudinal vibration modes of microtubule.

    Science.gov (United States)

    Cifra, M; Pokorný, J; Havelka, D; Kucera, O

    2010-05-01

    Microtubules are electrically polar structures fulfilling prerequisites for generation of oscillatory electric field in the kHz to GHz region. Energy supply for excitation of elasto-electrical vibrations in microtubules may be provided from GTP-hydrolysis; motor protein-microtubule interactions; and energy efflux from mitochondria. We calculated electric field generated by axial longitudinal vibration modes of microtubules for random, and coherent excitation. In case of coherent excitation of vibrations, the electric field intensity is highest at the end of microtubule. The dielectrophoretic force exerted by electric field on the surrounding molecules will influence the kinetics of microtubule polymerization via change in the probability of the transport of charge and mass particles. The electric field generated by vibrations of electrically polar cellular structures is expected to play an important role in biological self-organization. 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Axial dipolar dynamo action in the Taylor-Green vortex.

    Science.gov (United States)

    Krstulovic, Giorgio; Thorner, Gentien; Vest, Julien-Piera; Fauve, Stephan; Brachet, Marc

    2011-12-01

    We present a numerical study of the magnetic field generated by the Taylor-Green vortex. We show that periodic boundary conditions can be used to mimic realistic boundary conditions by prescribing the symmetries of the velocity and magnetic fields. This gives insight into some problems of central interest for dynamos: the possible effect of velocity fluctuations on the dynamo threshold, and the role of boundary conditions on the threshold and on the geometry of the magnetic field generated by dynamo action. In particular, we show that an axial dipolar dynamo similar to the one observed in a recent experiment can be obtained with an appropriate choice of the symmetries of the magnetic field. The nonlinear saturation is studied and a simple model explaining the magnetic Prandtl number dependence of the super- and subcritical nature of the dynamo transition is given.

  15. Axial shape index calculation for the 3-level excore detector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Gon; Kim, Yong Hee; Kim, Byung Sop; Lee, Sang Hee; Cho, Sung Jae [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    A new method based on the alternating conditional expectation (ACE) algorithm is developed to calculate axial shape index (ASI) for the 3-level excore detector. The ACE algorithm, a type of nonparametric regression algorithms, yields an optimal relationship between a dependent variable and multiple independent variables. In this study, the simple correlation between ASI and excore detector signals is developed using the Younggwang nuclear power plant unit 3 (YGN-3) data without any preprocessing on the relationships between independent variables and dependent variable. The numerical results show that simple correlations exist between the three excore signals and ASI of the core. The accuracy of the new method is much better than those of the current CPC and COLSS algorithms. 5 refs., 2 figs., 2 tabs. (Author)

  16. Management of Sub-axial Cervical Spine Injuries

    Science.gov (United States)

    Zaveri, Gautam; Das, Gurdip

    2017-01-01

    Sub-axial cervical spine injuries are commonly seen in patients with blunt trauma. They may be associated with spinal cord injury resulting in tetraplegia and severe permanent disability. Immobilization of the neck, maintenance of blood pressure and oxygenation, rapid clinical and radiological assessment of all injuries, and realignment of the spinal column are the key steps in the emergency management of these injuries. The role of intravenous methylprednisolone administration in acute spinal cord injuries remains controversial. The definitive management of these injuries is based upon recognition of the fracture pattern, assessment of the degree of instability, the presence or absence of neurologic deficit, and other patient related factors that may influence the outcome. Nonoperative treatment comprises of some form of external immobilization for 8 to 12 weeks, followed by imaging to assess fracture healing, and to rule out instability. The goals of surgery are realignment of the vertebral column, decompression of the neural elements and instrumented stabilization. PMID:29200479

  17. Axial-resolution in depth from focus digital holography

    Science.gov (United States)

    van Rooij, Joseph; Kalkman, Jeroen

    2017-06-01

    We use digital holography to quantify surface topography of rough objects in full-field. We calculate the variance of the intensity image as a focus metric over a set of reconstruction distances for each pixel, which results in a focus metric curve. The distance where the variance peaks is an estimate for the depth. First we analyze the lateral resolution of this method using the Talbot effect and argue that sub-mm axial resolution is feasible. Then, using a Michelson setup without magnifying optics or lateral scanning we experimentally demonstrate that sub-mm FWHM width of the focus curve can be achieved. This is significantly better than what was previously reported using digital holography and could make this technique useful for characterising objects in art and machine vision.

  18. Intestinal dysbiosis and innate immune responses in axial spondyloarthritis.

    Science.gov (United States)

    Ciccia, Francesco; Ferrante, Angelo; Triolo, Giovanni

    2016-07-01

    Inflammatory innate and adaptive immune cell responses to commensal bacteria underlie the pathogenesis of human chronic inflammatory diseases. Intestinal dysbiosis has been described in patients with spondyloarthritis (SpA) and seems to be correlated with histologic and immunologic alterations. Purpose of this review is to discuss the relationship occurring between intestinal dysbiosis and innate immune responses in patients with axial SpA. Intestinal dysbiosis and differential activation of intestinal immune responses in patients with SpA have been demonstrated. Furthermore, innate cells that appear to be involved in the pathogenesis of SpA may control intestinal homeostasis through induction of apoptotic cell death and deletion of activated commensal bacteria-specific T cells. Although the evidence shows that dysbiosis occurs in SpA, it is not clear the role of dysbiosis in regulating innate immune responses in SpA. Relationships between cause and effect remain to be answered. http://links.lww.com/COR/A34.

  19. Seeing the Axial Line: Evidence from Wayfinding Experiments

    Directory of Open Access Journals (Sweden)

    Beatrix Emo

    2014-07-01

    Full Text Available Space-geometric measures are proposed to explain the location of fixations during wayfinding. Results from an eye tracking study based on real-world stimuli are analysed; the gaze bias shows that attention is paid to structural elements in the built environment. Three space-geometric measures are used to explain the data: sky area, floor area and longest line of sight. Together with the finding that participants choose the more connected street, a relationship is proposed between the individual cognitive processes that occur during wayfinding, relative street connectivity measured through space syntactic techniques and the spatial geometry of the environment. The paper adopts an egocentric approach to gain a greater understanding on how individuals process the axial map.

  20. Seeing the axial line: evidence from wayfinding experiments.

    Science.gov (United States)

    Emo, Beatrix

    2014-09-01

    Space-geometric measures are proposed to explain the location of fixations during wayfinding. Results from an eye tracking study based on real-world stimuli are analysed; the gaze bias shows that attention is paid to structural elements in the built environment. Three space-geometric measures are used to explain the data: sky area, floor area and longest line of sight. Together with the finding that participants choose the more connected street, a relationship is proposed between the individual cognitive processes that occur during wayfinding, relative street connectivity measured through space syntactic techniques and the spatial geometry of the environment. The paper adopts an egocentric approach to gain a greater understanding on how individuals process the axial map.

  1. An Axial Sliding Test for machine elements surfaces

    DEFF Research Database (Denmark)

    Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran

    2012-01-01

    Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, hence the development and spread of plateau-honed surface for cylinder...... turned rod against a mirror-polished sleeve. Qualitatively the multifunctional surfaces improve the friction conditions, but a more structured test campaign is required....... liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper a new test rig simulating pure sliding conditions is presented, dubbed Axial Sliding Test. It presents four major components: a rod, a sleeve...

  2. Predicting the Coupling Properties of Axially-Textured Materials

    Directory of Open Access Journals (Sweden)

    María E. Fuentes-Montero

    2013-10-01

    Full Text Available A description of methods and computer programs for the prediction of “coupling properties” in axially-textured polycrystals is presented. Starting data are the single-crystal properties, texture and stereography. The validity and proper protocols for applying the Voigt, Reuss and Hill approximations to estimate coupling properties effective values is analyzed. Working algorithms for predicting mentioned averages are given. Bunge’s symmetrized spherical harmonics expansion of orientation distribution functions, inverse pole figures and (single and polycrystals physical properties is applied in all stages of the proposed methodology. The established mathematical route has been systematized in a working computer program. The discussion of piezoelectricity in a representative textured ferro-piezoelectric ceramic illustrates the application of the proposed methodology. Polycrystal coupling properties, predicted by the suggested route, are fairly close to experimentally measured ones.

  3. The Three-Axial Earth Rotation: A New Mathematical Approach

    Science.gov (United States)

    Mioc, Vasile; Stavinschi, Magda

    The three-axial Earth's rotation is generally treated by quantitative methods. The seldom used qualitative analysis, which depicts the general evolution all along the motion, can offer supplementary information. Tackling the problem from such a viewpoint, we exploit its Hamiltonian description using Andoyer-type variables, and consider it via KAM (Kolmogorov-Arnold-Moser) theory. The system of motion equations fulfils the condition of so-called "isoenergetic nondegeneracy". In astronomical translation, this means that the Earth's rotation is "sure" for almost all initial conditions: the chances for a drastic change are extremely improbable; this corroborates the data provided by observations and quantitative analysis. Another result offered by KAM theory is that the polhody will always be confined to a relatively negligible area. As a final conclusion, the most various methods of mathematics, classical mechanics, celestial mechanics must be used to understand astronomical problems of essential importance, as the Earth's rotation is.

  4. Spectrum of sight line displacements in the axial meridian circle.

    Science.gov (United States)

    Bakhonskij, A. V.; Kostyuchenko, V. L.; Lazorenko, P. F.

    The authors analyze the residuals Δα cos δ and Δδ obtained in the reduction of star observations made with the axial meridian circle of the Main Astronomical Observatory, National Academy of Sciences of Ukraine. The mean autocorrelation functions, variances, and spectra are given. The averaging allowed for the bias of sample functions for finite measurement runs. The spectra expressed in [open square]″Hz are fitted by the two-component models g(f) = 563(T0f)-2.2+7.0 and g(f) = 242(T0f)-1.5+5.1 for right ascension and declination residuals, respectively, with T0 = 18000 s. The data are compared with those for the Bordeaux meridian circle of the classical type. The spectral low-frequency component is shown to be produced by thermal deformations of the instrument tube.

  5. Axially-Symmetric Radiation Field of Conical Monopole

    Science.gov (United States)

    Kuryliak, D. B.; Sharabura, O. M.

    2013-12-01

    The rigorous solution of the problem of axially-symmetric, TM-wave diffraction by the open end of the biconical scatterer,, whose one arm is a semi-infinite cone and the other - a finite, cone, is obtained. The bicone is irradiated by the ring magnetic, current field. The analytical regularization technique is applied, to obtain the problem solution. The limiting transition from the, biconical scatterer with arbitrary values of angular parameters, to the monopole antenna (a finite hollow cone above the plane), is performed. The influence of the monopole's geometrics and, the source location on the far-field patterns is investigated. In particular cases, the results are compared with the known data.

  6. Treatment with tumor necrosis factor inhibitors in axial spondyloarthritis

    DEFF Research Database (Denmark)

    Ciurea, A.; Weber, U.; Stekhoven, D.

    2015-01-01

    Objective. To evaluate the initiation of and response to tumor necrosis factor (TNF) inhibitors for axial spondyloarthritis (axSpA) in private rheumatology practices versus academic centers. The Journal of Rheumatology, Methods.We compared newly initiated TNF inhibition for axSpA in 363 patients...... was slightly higher in the hospital setting. Mean levels (+/- SD) of the Ankylosing Spondylitis Disease Activity Score were, however, virtually identical in private practices and academic centers (3.4 +/- 1.0 vs 3.4 +/- 0.9, p = 0.68). An Assessment of SpondyloArthritis international Society (ASAS40) response...... in private practices in comparison to academic centers, adherence to ASAS treatment recommendations for TNF inhibition was equally high, and similar response rates to TNF blockers were achieved in both clinical settings. (First Release Nov 1 2014; J Rheumatol 2015; 42:101-5; doi 10.3899/jrheum.140229)....

  7. Numerical Algorithms for Boundary Problems with Disturbed Axial Symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, V

    2004-03-26

    The axial symmetry in the real devices of image electron optics is always disturbed by small defects in manufacturing and assembly. The authors present a complete method for the numerical simulation of problems with such defects, which includes the algorithms for singularity extraction in a numerical solution of the boundary problem described by the Helmholtz equation. The effective recurrent formulas for evaluation of the kernels of integral representations and their derivatives are constructed. New modification of the well-known Bruns-Bertein method is given, and correlation of this method with an integral equation in variations is investigated. The algorithms are implemented in the codes POISSON-2 and OPTICS-2. The results of the numerical simulation for various test problems with different kinds of boundary deformation are given.

  8. Operational Experience with a Cryogenic Axial-Centrifugal Compressor

    CERN Document Server

    Decker, L; Löhlein, K; Purtschert, W; Ziegler, B L; Lebrun, P; Tavian, L; Brunovsky, I; Tucek, L

    1998-01-01

    The Large Hadron Collider (LHC), presently under construction at CERN, requires large refrigeration capacity at 1.8 K. Compression of gaseous helium at cryogenic temperatures is therefore inevitable. Together with subcontractors, Linde Kryotechnik has developed a prototype machine. This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating at ambient temperature. Integrated in a test facility for superconducting magnets the machine has been commissioned without major problems and successfully gone through the acceptance test in autumn 1995. Subsequent steps were initiated to improve efficiency of this prototype. This paper describes operating experience gained so far and reports on measured performance prior to and after constructional modifications.

  9. Characteristic experiment of swashplate type axial piston motor (I)

    Energy Technology Data Exchange (ETDEWEB)

    Yum, M.O. [Kyongnam National University, Masan (Korea); Yoon, I.R. [Kyongnam National University Graduate School, Masan (Korea)

    2000-04-01

    The purpose of this study is to construct a testing equipment with which several characteristics of the domestically developed swashplate type axial piston motor can be tested and to develop a software with which the data from experiment can be stored and can be applied. The results of the study are as follows; 1) The leakage flow and the torque of the motor being stopped is proportional to supply pressure and their relation can be showed by linear equations. 2) The motor movement is not smooth below 50 rpm but it moves smoothly up 170 rpm. 3) When the motor starts or stops, the pressure rise ratio effects decisively to the max. torque. (author). 7 refs., 12 figs., 2 tabs.

  10. Structures of water molecular nanotube induced by axial tensile strains

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. [Key Laboratory of Liquid Structures and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University (China)], E-mail: lihuilmy@hotmail.com; Zhang, X.Q. [Physics Department, Ocean University of China, Qingdao (China); Liew, K.M. [Department of Building and Constructions, City University of Hong Kong, Kowloon (Hong Kong); Liu, X.F. [Key Laboratory of Liquid Structures and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University (China)

    2008-10-06

    Five well-ordered nano-ice structures embedded in carbon nanotubes are obtained in this study. These five nano-ice phases all exhibit single walled tubular morphologies, including the pentagon, hexagon ice nanotubes whose structures are quite different from bulk ice. Our simulation results indicate that water molecules tend to rearrange into surface ring structures to reduce the number of free OH groups. The structural behavior of these ice nanotubes inside CNTs subject to axial stress is also investigated. The ice nanotubes tend to be drawn to ice nanorings or ice nanospring during the mechanical stretching. The distribution function exhibits typical order-to-disorder transition of the water network confined in carbon nanotube during the stretching. By analysis, we suggest that it is unlikely that additional water molecules will enter the tubes because of the increased volume available if the tubes are stretched at contact with a water reservoir.

  11. Simulation of the stationary particle distribution in axial channeling

    Energy Technology Data Exchange (ETDEWEB)

    Pokhyl, G.P.; Cherdyntsev, V.V. (Moskovskij Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki)

    1982-01-01

    A mathematical model is developed for particle distribution in axial channeling through crystals. Results are shown for particle distribution in the transverse plane for various depths and initial conditions in (a) W <100> and (b) Si <100>. The distribution of impact parameters of the particle-string collisions was studied as a function of depth. The distribution function in the transverse plane for a single particle is plotted as its trajectory is traced to 0.2 mm depths at E(transverse) = 0.4 Esub(c) in W <100> (where E(transverse) is the energy of transverse motion and Esub(c) is the Lindhard critical energy of transverse motion).

  12. Active surge control for variable speed axial compressors.

    Science.gov (United States)

    Lin, Shu; Yang, Chunjie; Wu, Ping; Song, Zhihuan

    2014-09-01

    This paper discusses active surge control in variable speed axial compressors. A compression system equipped with a variable area throttle is investigated. Based on a given compressor model, a fuzzy logic controller is designed for surge control and a proportional speed controller is used for speed control. The fuzzy controller uses measurements of the change of pressure rise as well as the change of mass flow to determine the throttle opening. The presented approach does not require the knowledge of system equilibrium or the surge line. Numerical simulations show promising results. The proposed fuzzy logic controller performs better than a backstepping controller and is capable to suppress surge at different operating points. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Thermoacoustic mixture separation with an axial temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Geller, Drew W [Los Alamos National Laboratory; Swift, Gregory A [Los Alamos National Laboratory

    2008-01-01

    The theory of thermoacoustic mixture separation is extended to include the effect of a nonzero axial temperature gradient. The analysis yields a new term in the second-order mole flux that is proportional to the temperature gradient and to the square of the volumetric velocity and is independent of the phasing of the wave. Because of this new term, thermoacoustic separation stops at a critical temperature gradient and changes direction above that gradient. For a traveling wave, this gradient is somewhat higher than that predicted by a simple four-step model. An experiment tests the theory for temperature gradients from 0 to 416 K/m in 50-50 He-Ar mixtures.

  14. Collimation of laser-produced plasmas using axial magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Amitava; Harilal, Sivanandan S.; Hassan, Syed M.; Endo, Akira; Mocek, Tomas; Hassanein, A.

    2015-06-01

    We investigated the expansion dynamics of laser-produced plasmas expanding into an axial magnetic field. Plasmas were generated by focusing 1.064 µm Nd:YAG laser pulses onto a planar tin target in vacuum and allowed to expand into a 0.5 T magnetic-filed where field lines were aligned along the plume expansion direction. Gated images employing intensified CCD showed focusing of the plasma plume, which were also compared with results obtained using particle-in-cell modelling methods. The estimated density and temperature of the plasma plumes employing emission spectroscopy revealed significant changes in the presence and absence of the 0.5T magnetic field. In the presence of the field, the electron temperature is increased with distance from the target, while the density showed opposite effects.

  15. New turbomolecular pump with central opening for free axial access

    CERN Document Server

    Mokler, P H

    2004-01-01

    Standard turbomolecular pumps show typically one annular active intake area on the high vacuum flange side (single-flow pumps). The central circular part of the inlet of the compressor turbine is blind for pumping. The new design proposes a central opening of a turbomolecular pump all along the axis. This central bore can be used e.g. for mounting of feed throughs, manipulators, windows or for coupling to further vacuum devices, in particular also for enclosing tube-like vacuum systems. This design allows a multi-use of a pumping port at a vacuum vessel without reducing there the pumping speed. Moreover, the new design is ideal for axial or radial differential pumping arrangements as e.g. needed for all gas jet like set-ups or other pressure reduction stages.

  16. Three-dimensional equilibria in axially symmetric tokamaks

    Science.gov (United States)

    Garabedian, Paul R.

    2006-01-01

    The NSTAB and TRAN computer codes have been developed to study equilibrium, stability, and transport in fusion plasmas with three-dimensional (3D) geometry. The numerical method that is applied calculates islands in tokamaks like the Doublet III-D at General Atomic and the International Thermonuclear Experimental Reactor. When bifurcated 3D solutions are used in Monte Carlo computations of the energy confinement time, a realistic simulation of transport is obtained. The significance of finding many 3D magnetohydrodynamic equilibria in axially symmetric tokamaks needs attention because their cumulative effect may contribute to the prompt loss of α particles or to crashes and disruptions that are observed. The 3D theory predicts good performance for stellarators. PMID:17159158

  17. Hysteretic Models Considering Axial-Shear-Flexure Interaction

    Science.gov (United States)

    Ceresa, Paola; Negrisoli, Giorgio

    2017-10-01

    Most of the existing numerical models implemented in finite element (FE) software, at the current state of the art, are not capable to describe, with enough reliability, the interaction between axial, shear and flexural actions under cyclic loading (e.g. seismic actions), neglecting crucial effects for predicting the nature of the collapse of reinforced concrete (RC) structural elements. Just a few existing 3D volume models or fibre beam models can lead to a quite accurate response, but they are still computationally inefficient for typical applications in earthquake engineering and also characterized by very complex formulation. Thus, discrete models with lumped plasticity hinges may be the preferred choice for modelling the hysteretic behaviour due to cyclic loading conditions, in particular with reference to its implementation in a commercial software package. These considerations lead to this research work focused on the development of a model for RC beam-column elements able to consider degradation effects and interaction between the actions under cyclic loading conditions. In order to develop a model for a general 3D discrete hinge element able to take into account the axial-shear-flexural interaction, it is necessary to provide an implementation which involves a corrector-predictor iterative scheme. Furthermore, a reliable constitutive model based on damage plasticity theory is formulated and implemented for its numerical validation. Aim of this research work is to provide the formulation of a numerical model, which will allow implementation within a FE software package for nonlinear cyclic analysis of RC structural members. The developed model accounts for stiffness degradation effect and stiffness recovery for loading reversal.

  18. Axial ion-electron emission microscopy of IC radiation hardness

    Science.gov (United States)

    Doyle, B. L.; Vizkelethy, G.; Walsh, D. S.; Swenson, D.

    2002-05-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV/amu. The electronic stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 μm in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

  19. Analysis of brushless DC generator incorporating an axial field coil

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Hassan, E-mail: H_moradi@sbu.ac.i [Department of Electrical and Computer Engineering, Shahid Beheshti University, GC, Tehran (Iran, Islamic Republic of); Afjei, E. [Department of Electrical and Computer Engineering, Shahid Beheshti University, GC, Tehran (Iran, Islamic Republic of)

    2011-07-15

    Highlights: {yields} Magnetic analysis and experiment of a three-phase field assisted BLDC generator. {yields} Confirm the accuracy of the predicted flux-linkage by 2-D FE analysis. {yields} Confirm the accuracy of the FE analysis results by coupling the FE and BE method. {yields} Control the output voltage to a desired level by control the amplitude of the I{sub f}. {yields} Compatible with any application that requires variable speed operation. -- Abstract: This paper describes the magnetic analysis and experiment of a three-phase field assisted brushless DC (BLDC) generator. Unlike conventional BLDC generators, the permanent magnet is replaced with an assisted field winding. The stator and rotor are constructed with two dependent magnetically sets, in which each stator set includes nine salient poles with coil windings, and the rotor comprises of six salient poles. Other pole combinations also are possible. This construction is similar to a homopolar inductor alternator. The DC current in the assisted field winding produces axial flux which makes the rotor magnetically polarized at its ends. The magnetic field flows axially through the rotor shaft and closes through the stator teeth and the machine housing. To evaluate the generator performance, two types of analysis, namely the numerical technique and the experimental study have been utilized. In the numerical analysis, 2-D finite element (FE) analysis has been carried out using a MagNet CAD package (Infolytica Corporation Ltd.), to confirm the accuracy of the predicted flux-linkage characteristics, whereas in the experimental study, a prototype BLDC generator was constructed for verifying the actual performance. Furthermore, the evaluation method based on a hybrid numerical method coupling the finite element (FE) analysis and boundary element (BE) method, has been carried out to confirm the accuracy of the 2-D FE analysis simulation results. It provides not only confirmations of the investigation in results

  20. Axial turbomachine modelling with a 1D axisymmetric approach

    Energy Technology Data Exchange (ETDEWEB)

    Tauveron, Nicolas [Commissariat a l' Energie Atomique, Direction de l' Energie Nucleaire, 17 rue des Martyrs, 38100 Grenoble (France)]. E-mail: nicolas.tauveron@cea.fr; Saez, Manuel [Commissariat a l' Energie Atomique, Direction de l' Energie Nucleaire, 17 rue des Martyrs, 38100 Grenoble (France)]. E-mail: manuel.saez@cea.fr; Ferrand, Pascal [Laboratoire de Mecanique des Fluides et d' Acoustique, Ecole Centrale de Lyon, 36 avenue de Collongue, 69134 Ecully Cedex (France)]. E-mail: pascal.ferrand@ec-lyon.fr; Leboeuf, Francis [Laboratoire de Mecanique des Fluides et d' Acoustique, Ecole Centrale de Lyon, 36 avenue de Collongue, 69134 Ecully Cedex (France)]. E-mail: francis.leboeuf@ec-lyon.fr

    2007-09-15

    This work concerns the design and safety analysis of direct cycle gas cooled reactor. The estimation of compressor and turbine performances in transient operations is of high importance for the designer. The first goal of this study is to provide a description of compressor behaviour in unstable conditions with a better understanding than the models based on performance maps ('traditional' 0D approach). A supplementary objective is to provide a coherent description of the turbine behaviour. The turbomachine modelling approach consists in the solution of 1D axisymmetric Navier-Stokes equations on an axial grid inside the turbomachine: mass, axial momentum, circumferential momentum and total-enthalpy balances are written. Blade forces are taken into account by using compressor or turbine blade cascade steady correlations. A particular effort has been developed to generate or test correlations in low mass flow and negative mass flow regimes, based on experimental data. The model is tested on open literature cases of the gas turbine aircraft community. For compressor and turbine, steady situations are fairly described, especially for medium and high mass flow rate. The dynamic behaviour of compressor is also quite well described, even in unstable operation (surge): qualitative tendencies (role of plenum volume and role of throttle) and some quantitative characteristics (frequency) are in a good agreement with experimental data. The application to transient simulations of gas cooled nuclear reactors is concentrated on the hypothetical 10 in. break accident. The results point out the importance of the location of the pipe rupture in a hypothetical break event. In some detailed cases, compressor surge and back flow through the circuit can occur. In order to be used in a design phase, a simplified model of surge has also been developed. This simplified model is applied to the gas fast reactor (GFR) and compared quite favourably with 1D axisymmetric simulation

  1. Axial magnetic field injection in magnetized liner inertial fusion

    Science.gov (United States)

    Gourdain, P.-A.; Adams, M. B.; Davies, J. R.; Seyler, C. E.

    2017-10-01

    MagLIF is a fusion concept using a Z-pinch implosion to reach thermonuclear fusion. In current experiments, the implosion is driven by the Z-machine using 19 MA of electrical current with a rise time of 100 ns. MagLIF requires an initial axial magnetic field of 30 T to reduce heat losses to the liner wall during compression and to confine alpha particles during fusion burn. This field is generated well before the current ramp starts and needs to penetrate the transmission lines of the pulsed-power generator, as well as the liner itself. Consequently, the axial field rise time must exceed hundreds of microseconds. Any coil capable of being submitted to such a field for that length of time is inevitably bulky. The space required to fit the coil near the liner, increases the inductance of the load. In turn, the total current delivered to the load decreases since the voltage is limited by driver design. Yet, the large amount of current provided by the Z-machine can be used to produce the required 30 T field by tilting the return current posts surrounding the liner, eliminating the need for a separate coil. However, the problem now is the field penetration time, across the liner wall. This paper discusses why skin effect arguments do not hold in the presence of resistivity gradients. Numerical simulations show that fields larger than 30 T can diffuse across the liner wall in less than 60 ns, demonstrating that external coils can be replaced by return current posts with optimal helicity.

  2. Local Helioseismology

    Directory of Open Access Journals (Sweden)

    Gizon Laurent

    2005-11-01

    Full Text Available We review the current status of local helioseismology, covering both theoretical and observational results. After a brief introduction to solar oscillations and wave propagation through inhomogeneous media, we describe the main techniques of local helioseismology: Fourier-Hankel decomposition, ring-diagram analysis, time-distance helioseismology, helioseismic holography, and direct modeling. We discuss local helioseismology of large-scale flows, the solar-cycle dependence of these flows, perturbations associated with regions of magnetic activity, and solar supergranulation.

  3. Effect of axial deformation on the flexural behavior of one-bay multi ...

    African Journals Online (AJOL)

    Most structural analysts assume in their analysis of multi-storey frames that axial deformations are negligible compared to flexural deformations. The result of this assumption is that such analysts ignore the effects of axial deformation on their analysis by treating both beams and columns as flexural elements. The present ...

  4. Guided wave propagation as a measure of axial loads in rails

    CSIR Research Space (South Africa)

    Loveday, PW

    2010-03-01

    Full Text Available Guided wave propagation has been proposed as a means to monitor the axial loads in continuously welded railway rails although no practical system has been developed. In this paper, the influence of axial load on the guided wave propagation...

  5. Indigenous development of a 2 kW RF-excited fast axial flow CO2 ...

    Indian Academy of Sciences (India)

    Abstract. RF-excited fast axial flow CO2 lasers in kilowatt regime are presently being used for various new scientific applications in addition to laser material processing because of its versatility and superior beam quality. We have indigenously developed a compact. 2 kW RF-excited fast axial flow CO2 laser with moderate ...

  6. Cavitation in centrifugal pump with rotating walls of axial inlet device

    Science.gov (United States)

    Moloshnyi, O.; Sotnyk, M.

    2017-08-01

    The article deals with the analysis of cavitation processes in the flowing part of the double entry centrifugal pump. The analysis is conducted using numerical modeling of the centrifugal pump operating process in the software environment ANSYS CFX. Two models of the axial inlet device is researched. It is shaped by a cylindrical section and diffuser section in front of the impeller, which includes fairing. The walls of the axial inlet device rotate with the same speed as the pump rotor. The numerical experiment is conducted under the condition of the flow rate change and absolute pressure at the inlet. The analysis shows that the pump has the average statistical cavitation performance. The occurrence of the cavitation in the axial inlet device is after narrowing the cross-section of flow channel and at the beginning of the diffuser section. Additional sudden expansion at the outlet of the axial inlet diffuser section does not affect the cavitation characteristics of the impeller, however, improves cavitation characteristics of the axial inlet device. For considered geometric parameters of the axial inlet device the cavitation in the impeller begins earlier than in the axial inlet device. That is, the considered design of the axial inlet device will not be subjected to destruction at the ensuring operation without cavitation in the impeller.

  7. A benchmark study of procedures for analysis of axial crushing of bulbous bows

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Pedersen, Preben Terndrup

    2008-01-01

    Simplified methods to estimate mean axial crushing forces of plated structures are reviewed and applied to a series of experimental results for axial crushing of large-scale bulbous bow models. Methods based on intersection unit elements such as L-, T- and X-type elements as well as methods based...

  8. An exact dynamic stiffness matrix for axially loaded double-beam ...

    Indian Academy of Sciences (India)

    tions of the axially loaded double-beam system in free vibration by using the Laplace transform method. An example is given to demonstrate the effectiveness of this method, in which ten boundary conditions are investigated and the effect of the axial force on the natural frequencies and mode shapes of the double-beam ...

  9. Subfoveal choroidal thickness in relation to sex and axial length in 93 Danish university students

    DEFF Research Database (Denmark)

    Li, Xiao Qiang; Larsen, Michael; Munch, Inger Christine

    2011-01-01

    To investigate the association between subfoveal choroidal thickness and ocular axial length, refractive error, and blood pressure in healthy young women and men.......To investigate the association between subfoveal choroidal thickness and ocular axial length, refractive error, and blood pressure in healthy young women and men....

  10. The effect of axial ligand on the oxidation of syringyl alcohol by Co(salen) adducts

    Science.gov (United States)

    Thomas Elder; Joseph Bozell; Diana Cedeno

    2013-01-01

    Experimental work on the oxidation of the lignin model, syringyl alcohol, using oxygen and a Co(salen) catalyst has revealed variations in yield with different imidazole-based axial ligands. A reasonable linear relationship was found between product yield and pKa of the axial ligand. The current work, using density functional calculations, examined geometric,...

  11. Clinical evaluation of internal axial wall divergence in inlays and casting post-and-core fabrication

    Directory of Open Access Journals (Sweden)

    Min-Chieh Hsieh

    2015-06-01

    Conclusion: Compared with the teeth preparation of external axial wall in a single crown, the sighted distance at 30-cm distance in the internal axial wall is 1.5 × wider. More sighted distances are required to prevent undesired undercuts.

  12. Page 1 268 axes and axial planes of minor folds. This, together with ...

    Indian Academy of Sciences (India)

    seen in a few exposures. In an exposure north of. Dattatreyapitha the axes and axial planes of the dominant set are bent by later folds having nearly N-S trending axial planes (figures 10a, 11b). Near Jensuri- gudda dome and basin patterns have been produced by the interference of WNW-ESE and NE–SW trending folds.

  13. Effect of a regular arrangement of the strings upon the energy losses of axially channeled particles

    Energy Technology Data Exchange (ETDEWEB)

    Pokhil, G.P.; Cherdyntsev, V.V. (Moskovskij Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki)

    1984-10-01

    The excess of the channel-to-random energy losses ratio over unity in axial channeling at shallow depths is accounted for by the effect of a regular arrangement of the strings. This effect is also responsible for some other features arising in axial channeling.

  14. An electrostatic lower stator axial-gap polysilicon wobble motor part I: Design and modeling

    NARCIS (Netherlands)

    Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; van Baar, J.J.J.; Elwenspoek, Michael Curt

    This paper presents design issues and a theoretical model of electrostatically driven axial-gap polysilicon wobble motors. The motor design benefits from large axial rotor-to-stator overlap and large gear ratios, and motor designs with rotor radii of 50 and 100 μm are capable of generating torques

  15. An exact dynamic stiffness matrix for axially loaded double-beam ...

    Indian Academy of Sciences (India)

    An exact dynamic stiffness method is presented in this paper to determine the natural frequencies and mode shapes of the axially loaded double-beam systems,which consist of two homogeneous and prismatic beams with a distributed spring in parallel between them.The effects of the axial force, shear deformation and ...

  16. Analysis of Axial Flow Ventilation Fans by Vortex - Method.

    Science.gov (United States)

    Hardin, Richard Anthony

    A steady vortex-lattice method is used to solve the lifting surface equation for an axial flow fan. The type of fan studied is designed for industrial and ventilation applications and in thermofluid systems such as cooling towers. The fan blades are thin cambered surfaces manufactured from metal sheets. The numerical approach is inviscid and results in a boundary value problem with viscous effects partially accounted for by application of drag coefficient data. A non-linear wake alignment procedure is used to account for the effects of vorticity shedding in the wake and variation in wake geometry with operating conditions. The wake alignment procedure is semi-free with wake input parameters required for accurate use of the technique. A study of the wake parameters was conducted and gave trends in the variation of their values with flow rate. At "free-air" conditions, flow visualization estimates of these parameters were found to agree with those from the computations. Comparisons are made between the measured and predicted fan performance with and without a surrounding duct. The comparison of the results were especially good at the "free-air" condition using wake parameters determined from flow visualization and an inlet velocity profile measured using hot-wire anemometry. To enable better understanding of basic flow phenomena and to provide data for verification of numerical analyses, a method for measuring unsteady surface pressure on a rotating axial-flow fan blade was devised. Unsteadiness of pressure on the blade surfaces is due to the effects of upstream fan motor supports and other installation features. A pressure transducer and signal amplification circuit were mounted on a circuit board at the rotating hub with signals taken off the rotating shaft through copper disk-mercury slip rings. The pressure difference across the blade was determined and the data were corrected for time lag and distortion caused by the length of tubing. The pressure difference

  17. Anatomical Directional Dissimilarities in Tri-axial Swallowing Accelerometry Signals.

    Science.gov (United States)

    Movahedi, Faezeh; Kurosu, Atsuko; Coyle, James L; Perera, Subashan; Sejdic, Ervin

    2017-05-01

    Swallowing accelerometry is a noninvasive approach currently under consideration as an instrumental screening test for swallowing difficulties, with most current studies focusing on the swallowing vibrations in the anterior-posterior (A-P) and superior-inferior (S-I) directions. However, the displacement of the hyolaryngeal structure during the act of swallowing in patients with dysphagia involves declination of the medial-lateral (M-L), which suggests that the swallowing vibrations in the M-L direction have the ability to reveal additional details about the swallowing function. With this motivation, we performed a broad comparison of the swallowing vibrations in all three anatomical directions. Tri-axial swallowing accelerometry signals were concurrently collected from 72 dysphagic patients undergoing videofluoroscopic evaluation of swallowing (mean age: 63.94 ± 12.58 years period). Participants swallowed one or more thickened liquids with different consistencies including thin-thick liquids, nectar-thick liquids, and pudding-thick liquids with either a comfortable self-selected volume from a cup or a controlled volume by the examiner from a 5-ml spoon. Swallows were grouped based on the viscosity of swallows and the participant's stroke history. Then, a comprehensive set of features was extracted in multiple signal domains from 881 swallows. The results highlighted inter-axis dissimilarities among tri-axial swallowing vibrations including the extent of variability in the amplitude of signals, the degree of predictability of signals, and the extent of disordered behavior of signals in time-frequency domain. First, the upward movement of the hyolaryngeal structure, representing the S-I signals, were actually more variable in amplitude and showed less predictable behavior than the sideways and forward movements, representing the A-P and M-L signals, during swallowing. Second, the S-I signals, which represent the upward movement of the hyolaryngeal structure

  18. NASA Glenn's Single-Stage Axial Compressor Facility Upgraded

    Science.gov (United States)

    Brokopp, Richard A.

    2004-01-01

    NASA Glenn Research Center's Single-Stage Axial Compressor Facility was upgraded in fiscal year 2003 to expand and improve its research capabilities for testing high-speed fans and compressors. The old 3000-hp drive motor and gearbox were removed and replaced with a refurbished 7000-hp drive motor and gearbox, with a maximum output speed of 21,240 rpm. The higher horsepower rating permits testing of fans and compressors with higher pressure ratio or higher flow. A new inline torquemeter was installed to provide an alternate measurement of fan and compressor efficiency, along with the standard pressure and temperature measurements. A refurbished compressor bearing housing was also installed with bidirectional rotation capability, so that a variety of existing hardware could be tested. Four new lubrication modules with backup capability were installed for the motor, gearbox, torquemeter, and compressor bearing housing, so that in case the primary pump fails, the backup will prevent damage to the rotating hardware. The combustion air supply line for the facility inlet air system was activated to provide dry air for repeatable inlet conditions. New flow conditioning hardware was installed in the facility inlet plenum tank, which greatly reduced the inlet turbulence. The new inlet can also be easily modified to accommodate 20- or 22-in.-diameter fans and compressors, so a variety of existing hardware from other facilities (such as Glenn's 9- by 15-Foot Low-Speed Wind Tunnel) can be tested in the Single-Stage Axial Compressor Facility. An exhaust line was also installed to provide bleed capability to remove the inlet boundary layer. To improve the operation and control of the facility, a new programmable logic controller (PLC) was installed to upgrade from hardwired relay logic to software logic. The PLC also enabled the usage of human-machine interface software to allow for easier operation of the facility and easier reconfiguration of the facility controls when

  19. Generalized hidden local symmetry model confronts the decay τ- → π+π-π-ντ

    Science.gov (United States)

    Achasov, N. N.; Kozhevnikov, A. A.

    2010-06-01

    Generalized Hidden Local Symmetry (GHLS) model as the chiral model of pseudoscalar, vector, and axial vector mesons, is confronted the ALEPH data on the decay τ- → π+π-π-ντ. It is shown that the spectrum of this decay in GHLS falls short of the experimental data. The modifications of GHLS based on inclusion of heavier axial vector mesons are studied. It is shown that the scheme with two additional axial vector isovector mesons with masses m a {1/'} = 1.59 GeV and m a {1/″} = 1.88 GeV gives a good description of the ALEPH data.

  20. Prebuckling and Postbuckling Response of Tailored Composite Stiffened Panels with Axial-Shear Coupling

    Science.gov (United States)

    Young, Richard D.; Hyer, Michael W.; Starnes, James H., Jr.

    2000-01-01

    Results of a numerical parametric study of the prebuckling and postbuckling response of tailored composite stiffened panels with axial-shear coupling are presented. In the stiffened panels, axial-shear stiffness coupling is created by rotating the stiffener orientation and tailoring the skin laminate anisotropy. The panels are loaded in axial compression and the effects of stiffener orientation and skin anisotropy on the panel stiffness, buckling parameters, and axial-shear coupling response are described. Results are obtained from a nonlinear general shell finite element analysis computer code. The prebuckling and postbuckling responses can be affected by both the stiffener orientation and skin laminate anisotropy, and the effects are different and load dependent. The results help identify different mechanisms for axial-shear coupling, and show that a load-dependent structural response can be controlled by selecting appropriate stiffener and skin parameters.

  1. Ultrastructural evidence of the excretory function in the asteroid axial organ (Asteroidea, Echinodermata).

    Science.gov (United States)

    Ezhova, O V; Egorova, E A; Malakhov, V V

    2016-05-01

    The ultrastructure of the axial organ of Asterias amurensis has been studied The organ is a network of canals of the axial coelom separated by haemocoelic spaces. The axial coelom is lined with two types of monociliary cells: podocytes and musculo-epithelial cells. Podocytes form numerous basal processes adjacent to the basal lamina on the coelomic side. Musculo-epithelial cells form processes running along the basal lamina. Some bundles of these processes wrapped in the basal lamina pass through haemocoelic spaces between neighboring coelomic canals. It is hypothesized that the axial organ serves for filtration of fluid from haemocoelic spaces into the axial coelom cavity, from which urine is excreted through the madreporite to the exterior.

  2. What changed during the axial age: Cognitive styles or reward systems?

    Science.gov (United States)

    Baumard, Nicolas; Hyafil, Alexandre; Boyer, Pascal

    2015-01-01

    The 'Axial Age' (500-300 BCE) refers to the period during which most of the main religious and spiritual traditions emerged in Eurasian societies. Although the Axial Age has recently been the focus of increasing interest,(1-5) its existence is still very much in dispute. The main reason for questioning the existence of the Axial Age is that its nature, as well as its spatial and temporal boundaries, remain very much unclear. The standard approach to the Axial Age defines it as a change of cognitive style, from a narrative and analogical style to a more analytical and reflective style, probably due to the increasing use of external memory tools. Our recent research suggests an alternative hypothesis, namely a change in reward orientation, from a short-term materialistic orientation to a long-term spiritual one.(6) Here, we briefly discuss these 2 alternative definitions of the Axial Age.

  3. Oseen's correction to stokes drag on axially symmetric arbitrary particle in transverse flow: A new approach

    Directory of Open Access Journals (Sweden)

    Srivastava Deepak Kumar

    2014-01-01

    Full Text Available In this paper, Oseen’s correction to Stokes drag experienced by axially symmetric particle placed in a uniform stream perpendicular to axis of symmetry(i.e. transverse flow is obtained. For this, the linear relationship between axial and transverse Stokes drag is utilized to extend the Brenner’s formula for axial flow to transverse flow. General expression of Oseen’s correction to Stokes drag on axially symmetric particle placed in transverse flow is found to be new. This general expression is applied to some known axially symmetric bodies and obtained values of Oseen’s drag, up to first order terms in Reynolds number ‘R’, are also claimed to be new and never exist in the literature. Numerical values of Oseen drag are also evaluated and their variations with respect to Reynolds number, eccentricity and deformation parameter are depicted in figures and compared with some known values. Some important applications are also highlighted.

  4. What changed during the axial age: Cognitive styles or reward systems?

    Science.gov (United States)

    Baumard, Nicolas; Hyafil, Alexandre; Boyer, Pascal

    2015-01-01

    The ‘Axial Age’ (500–300 BCE) refers to the period during which most of the main religious and spiritual traditions emerged in Eurasian societies. Although the Axial Age has recently been the focus of increasing interest,1-5 its existence is still very much in dispute. The main reason for questioning the existence of the Axial Age is that its nature, as well as its spatial and temporal boundaries, remain very much unclear. The standard approach to the Axial Age defines it as a change of cognitive style, from a narrative and analogical style to a more analytical and reflective style, probably due to the increasing use of external memory tools. Our recent research suggests an alternative hypothesis, namely a change in reward orientation, from a short-term materialistic orientation to a long-term spiritual one.6 Here, we briefly discuss these 2 alternative definitions of the Axial Age. PMID:27066164

  5. Localized Scleroderma

    Science.gov (United States)

    ... scleroderma, or who are experts at examining the skin, can arrive at the diagnosis without much difficulty after a careful examination. In ... especially in patients who continue to have active skin problems or develop new ... Diagnosis of Localized Scleroderma? The diagnosis of localized scleroderma ...

  6. Net Locality

    DEFF Research Database (Denmark)

    de Souza e Silva, Adriana Araujo; Gordon, Eric

    Provides an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps...... of emerging technologies, from GeoCities to GPS, Wi-Fi, Wiki Me, and Google Android....

  7. Strength and dynamic characteristics analyses of wound composite axial impeller

    Science.gov (United States)

    Wang, Jifeng; Olortegui-Yume, Jorge; Müller, Norbert

    2012-03-01

    A low cost, light weight, high performance composite material turbomachinery impeller with a uniquely designed blade patterns is analyzed. Such impellers can economically enable refrigeration plants to use water as a refrigerant (R718). A strength and dynamic characteristics analyses procedure is developed to assess the maximum stresses and natural frequencies of these wound composite axial impellers under operating loading conditions. Numerical simulation using FEM for two-dimensional and three-dimensional impellers was investigated. A commercially available software ANSYS is used for the finite element calculations. Analysis is done for different blade geometries and then suggestions are made for optimum design parameters. In order to avoid operating at resonance, which can make impellers suffer a significant reduction in the design life, the designer must calculate the natural frequency and modal shape of the impeller to analyze the dynamic characteristics. The results show that using composite Kevlar fiber/epoxy matrix enables the impeller to run at high tip speed and withstand the stresses, no critical speed will be matched during start-up and shut-down, and that mass imbalances of the impeller shall not pose a critical problem.

  8. [Influence of axial length in refractive outcome after cataract surgery].

    Science.gov (United States)

    de Juan, V; Martín, R; Pérez, I; Herreras, J M

    2010-04-01

    To analyse the influence of axial length (AL) and age on refractive outcome after cataract surgery in terms of uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA) and subjective refraction. A retrospective review of 171 consecutive cases of uncomplicated cataract surgery was done. The refractive outcome was analysed (UCVA, BCVA and postoperative retraction) according AL before surgery (AL 25 mm) and age ( 60 years). After surgery mean UCVA was 0.6 ± 0.33 Diopters (D) and mean BCVA was 0.93 ± 0.23 D. Mean refractive outcome was 0.89 ± 0.78 D. There were no significant differences in post-operative UCVA, BCVA and refraction between the three age groups. There were statistically significant differences (p = 0.004) in UCVA between the three AL groups. The group with AL between 22 and 25 mm had better UCVA. Mean refractive outcome was -0.95 ± 1.91 D in the group with AL 25 mm. AL influences refractive outcome and UCVA after cataract surgery. Eyes with AL refractive outcome.

  9. Experimental research regarding the performance of small axial turbines

    Directory of Open Access Journals (Sweden)

    Sanda BUDEA

    2013-09-01

    Full Text Available This paper continues research of the authors and presents some theoretical aspects regarding the maximum power extract from the wind turbines, the optimal incidence angle, the best twisting of the blade and experimental research done in the laboratory of Renewable Energy from the Hydraulics, Hydraulic Machineries and Environmental Engineering Department, on small axial turbines, with impeller of 500 mm and 2000 mm in 3 constructive variants: with 3, 4 and respectively 8 blades. These turbines can have applications both aerodynamic - wind turbines but also hydrodynamic.It was determined the provided power, the starting / braking torque of the impeller and the power coefficients for these three type of turbines. From the experimental research resulted that the best behavior had the small impeller of 500 mm, with four bladed with cp = 0.56, tested in water, than the 500 mm impeller with three blades having the power coefficient cp = 0.43, tested in air and the last impeller, with 2000 mm and 8 bladed, has about cp = 0.4, tested in air too. These experimental results are the basis of various aerodynamic and hydrodynamic applications and further research.

  10. A paleointensity test of the geocentric axial dipole (GAD) hypothesis

    Science.gov (United States)

    Veikkolainen, Toni; Heimpel, Moritz; Evans, Michael E.; Pesonen, Lauri J.; Korhonen, Kimmo

    2017-04-01

    The geocentric axial dipole (GAD) model is central to many aspects of geophysics, including plate tectonics and paleoclimate. But its validity is by no means firmly established, particularly for the Precambrian. One test that has met with some success involves the distribution of paleomagnetic inclination angles. It works because any given field morphology has its own distinct probability distribution function (PDF) against which data compilations can be tested. Here, we investigate a second possible test using published paleointensity data. Once again, any given field morphology has a specific PDF of intensity. Likely field models consist of an underlying GAD on which is superimposed modest zonal quadrupole and octupole components. The corresponding paleointensity PDFs turn out to have more complicated shapes than their inclination counterparts, often having multiple maxima and minima. Given sufficient data, this complexity offers greater discrimination between models. In this paper, the potential of the paleointensity test is assessed using an extension of the PINT paleointensity database. We found it useful to analyse the Phanerozoic and Precambrian intervals separately. Despite the inherent limitations of this kind of analysis, a tripartite geodynamo with small zonal multipoles appears to be a good starting point on a way towards more fine-tuned models.

  11. Vortex sinks with axial flow: Solution and applications

    Science.gov (United States)

    Shtern, Vladimir; Borissov, Anatoly; Hussain, Fazle

    1997-10-01

    In this paper we develop a new class of analytical solutions of the Navier-Stokes equations and suggest ways to predict and control complex swirling flows. We consider vortex sinks on curved axisymmetric surfaces with an axial flow and obtain a five-parameter solution family that describes a large variety of flow patterns and models fluid motion in a cylindrical can, whirlpools, tornadoes, and cosmic swirling jets. The singularity of these solutions on the flow axis is removed by matching them with swirling jets. The resulting composite solutions describe flows, consisting of up to seven separation regions (recirculatory "bubbles" and vortex rings), and model flows in the Ranque-Hilsch tube, in the meniscus of electrosprays, in vortex breakdown, and in an industrial vortex burner. The analytical solutions allow a clear understanding of how different control parameters affect the flow and guide selection of optimal parameter values for desired flow features. The approach permits extension to swirling flows with heat transfer and chemical reaction, and have the potential of being significantly useful for further detailed investigation by direct or large-eddy numerical simulations as well as laboratory experimentation.

  12. Investigation of unsteady flow in axial turbine stage

    Directory of Open Access Journals (Sweden)

    Němec Martin

    2012-04-01

    Full Text Available The never ending process to increase the efficiency of turbine stages introduced an idea to create an axial turbine stage test rig as part of closed loop transonic wind tunnel at Vyzkumny a zkusebni letecky ustav (VZLU. Studying of unsteady flow field behaviours in turbine stages is nowadays essential in the development process. Therefore, the test rig was designed with focusing on possibility of detailed studying of unsteady flow fields in turbine stages. New methodologies and new instrumentations were developed at VZLU and successfully integrated to gain valuable information from experiments with turbine stages. Two different turbine stages were tested during the facility introduction process. The measurement of these two models demonstrated how flexible the test rig is. One of them was an enlarged model of small gas turbine stage. The other was scaled-down model of stage of intermediate-pressure steam turbine. The external characteristics of both models were acquired during experiments as well as the detailed unsteady flow field measurement. Turbine stages were tested in various regimes in order to check the capabilities of the facility, methodology and instrumentation together. The paper presents results of unsteady flow field investigation in the enlarged turbine stage with unshrouded rotor. The interaction of structures developed in a stator with the rotor flow field is depicted and the influence of turbine load on evolution of secondary flows in rotor is analysed.

  13. Modeling of Axial Spring Stiffness in Active Vibration Controlled Drilling

    Directory of Open Access Journals (Sweden)

    Pao William

    2014-07-01

    Full Text Available During drilling process, substantial amount of vibration and shock are induced to the drill string. Active vibration controlled drilling is introduced to reduce the vibration and increase the efficiency of drilling process. In this system, two main components that determine the damping coefficient are magnetorheological (MR damper and spring assembly. Performance of vibration damping system is depending on the viscosity of MR fluid in the damper and spring constant of spring assembly. One of the key issues that are unclear from the design is the correlation between the axial spring stiffness configuration and the damping force which needs to be tuned actively. There has been lack of studies on how the viscosity of MR fluid on the active vibration damper affects the damping stiffness of the whole system. The objective of the project is to extract the correlations for the viscous damping coefficient, equivalent spring stiffness and power input to the system. Simplified vibration model is thus created using Simulink, together with experimental data fed from APS Technology’s in-house team. Inputs of the simulation such as force exerted, mass of mandrel, spring constant and step time are based on the experimental data and can be adjusted to suit different experiments. By having the model, behavior of the system can be studied and analyzed. From the simulation, it is also observed that the relationship between damping coefficient and power input of the system is linear.

  14. Numerical optimisation of an axial turbine; Numerische Optimierung einer Axialturbine

    Energy Technology Data Exchange (ETDEWEB)

    Welzel, B.

    1998-12-31

    The author presents a method for automatic shape optimisation of components with internal or external flow. The method combines a program for numerical calculation of frictional turbulent flow with an optimisation algorithm. Algorithms are a simplex search strategy and an evolution strategy. The shape of the component to be optimized is variable due to shape parameters modified by the algorithm. For each shape, a flow calculation is carried out on whose basis a functional value like performance, loss, lift or resistivity is calculated. For validation, the optimisation method is used in simple examples with known solutions. It is applied. It is applied to the components of a slow-running axial turbine. Components with accelerated and delayed rotationally symmetric flow and 2D blade profiles are optimized. [Deutsch] Es wird eine Methode zur automatischen Formoptimierung durchstroemter oder umstroemter Bauteile vorgestellt. Diese koppelt ein Programm zur numerischen Berechnung reibungsbehafteter turbulenter Stroemungen mit einem Optimierungsalgorithmus. Dabei kommen als Algorithmen eine Simplex-Suchstrategie und eine Evolutionsstrategie zum Einsatz. Die Form des zu optimierenden Koerpers ist durch Formparameter, die vom Algorithmus veraendert werden, variabel. Fuer jede Form wird eine Stroemungsberechnung durchgefuehrt und mit dieser ein Funktionswert wie Wirkungsgrad, Verlust, Auftrieb oder Widerstandskraft berechnet. Die Optimierungsmethode wird zur Validierung in einfachen Beispielen mit bekannter Loesung eingesetzt. Zur Anwendung kommt sie in den einzelnen Komponenten einer langsamlaeufigen Axialturbine. Es werden Bauteile mit beschleunigter und verzoegerter rotationssymmetrischer Stroemung und 2D-Schaufelprofile optimiert. (orig.)

  15. Axially symmetric equations for differential pulsar rotation with superfluid entrainment

    Science.gov (United States)

    Antonelli, M.; Pizzochero, P. M.

    2017-01-01

    In this article we present an analytical two-component model for pulsar rotational dynamics. Under the assumption of axial symmetry, implemented by a paraxial array of straight vortices that thread the entire neutron superfluid, we are able to project exactly the 3D hydrodynamical problem to a 1D cylindrical one. In the presence of density-dependent entrainment the superfluid rotation is non-columnar: we circumvent this by using an auxiliary dynamical variable directly related to the areal density of vortices. The main result is a system of differential equations that take consistently into account the stratified spherical structure of the star, the dynamical effects of non-uniform entrainment, the differential rotation of the superfluid component and its coupling to the normal crust. These equations represent a mathematical framework in which to test quantitatively the macroscopic consequences of the presence of a stable vortex array, a working hypothesis widely used in glitch models. Even without solving the equations explicitly, we are able to draw some general quantitative conclusions; in particular, we show that the reservoir of angular momentum (corresponding to recent values of the pinning forces) is enough to reproduce the largest glitch observed in the Vela pulsar, provided its mass is not too large.

  16. Axial acoustic radiation force on a sphere in Gaussian field

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Rongrong; Liu, Xiaozhou, E-mail: xzliu@nju.edu.cn; Gong, Xiufen [Key Laboratory of Modern Acoustics, Institute of Acoustics and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-10-28

    Based on the finite series method, the acoustical radiation force resulting from a Gaussian beam incident on a spherical object is investigated analytically. When the position of the particles deviating from the center of the beam, the Gaussian beam is expanded as a spherical function at the center of the particles and the expanded coefficients of the Gaussian beam is calculated. The analytical expression of the acoustic radiation force on spherical particles deviating from the Gaussian beam center is deduced. The acoustic radiation force affected by the acoustic frequency and the offset distance from the Gaussian beam center is investigated. Results have been presented for Gaussian beams with different wavelengths and it has been shown that the interaction of a Gaussian beam with a sphere can result in attractive axial force under specific operational conditions. Results indicate the capability of manipulating and separating spherical spheres based on their mechanical and acoustical properties, the results provided here may provide a theoretical basis for development of single-beam acoustical tweezers.

  17. Origin of axial prestretch and residual stress in arteries.

    Science.gov (United States)

    Cardamone, L; Valentín, A; Eberth, J F; Humphrey, J D

    2009-12-01

    The structural protein elastin endows large arteries with unique biological functionality and mechanical integrity, hence its disorganization, fragmentation, or degradation can have important consequences on the progression and treatment of vascular diseases. There is, therefore, a need in arterial mechanics to move from materially uniform, phenomenological, constitutive relations for the wall to those that account for separate contributions of the primary structural constituents: elastin, fibrillar collagens, smooth muscle, and amorphous matrix. In this paper, we employ a recently proposed constrained mixture model of the arterial wall and show that prestretched elastin contributes significantly to both the retraction of arteries that is observed upon transection and the opening angle that follows the introduction of a radial cut in an unloaded segment. We also show that the transmural distributions of elastin and collagen, compressive stiffness of collagen, and smooth muscle tone play complementary roles. Axial prestresses and residual stresses in arteries contribute to the homeostatic state of stress in vivo as well as adaptations to perturbed loads, disease, or injury. Understanding better the development of and changes in wall stress due to individual extracellular matrix constituents thus promises to provide considerable clinically important insight into arterial health and disease.

  18. Origin of Axial Prestretch and Residual Stress in Arteries*

    Science.gov (United States)

    Cardamone, L.; Valentin, A.; Eberth, J.F.; Humphrey, J.D.

    2009-01-01

    The structural protein elastin endows large arteries with unique biological functionality and mechanical integrity, hence its disorganization, fragmentation, or degradation can have important consequences on the progression and treatment of vascular diseases. There is, therefore, a need in arterial mechanics to move from materially uniform, phenomenological, constitutive relations for the wall to those that account for separate contributions of the primary structural constituents: elastin, fibrillar collagens, smooth muscle, and amorphous matrix. In this paper, we employ a recently proposed constrained mixture model of the arterial wall and show that prestretched elastin contributes significantly to both the retraction of arteries that is observed upon transection and the opening angle that follows the introduction of a radial cut in an unloaded segment. We also show that the transmural distributions of elastin and collagen, compressive stiffness of collagen, and smooth muscle tone play complementary roles. Axial prestresses and residual stresses in arteries contribute to the homeostatic state of stress in vivo as well as adaptations to perturbed loads, disease, or injury. Understanding better the development of and changes in wall stress due to individual extracellular matrix constituents thus promises to provide considerable clinically important insight into arterial health and disease. PMID:19123012

  19. Probing heterogeneity of cortical bone with ultrasound axial transmission.

    Science.gov (United States)

    Foiret, Josquin; Grimal, Quentin; Talmant, Maryline; Longo, Roberto; Laugier, Pascal

    2013-01-01

    In clinical examination of long cortical bones based on ultrasound axial transmission, the parameter currently used as indicator of bone fragility is the velocity of the first arriving signal (VFAS). VFAS is inherently related to the material properties of the bone site. However, experimental uncertainties may hide the true sensitivity of VFAS to elastic characteristics of bone. Measurements are performed with a multi-element compact array placed in contact with the bone. Therefore, VFAS measurements may be biased by variability imposed by geometrical irregularities of the sample below the probe and/or by probe misalignment. In this paper, we test the assumption that despite experimental errors, VFAS variations resulting from material properties can be measured. The methodology was to compare VFAS and velocities of compression bulk waves (VBWs) on carefully matched sites around the circumference of a test sample (bovine femur). VBW was mapped on bone cross-sections using a through-transmission technique. VBW and VFAS were highly correlated [R² = 0.80, root mean square error = 23 m·s⁻¹, p < 10⁻⁵] and the slope of the linear regression was close to 1 except in a part of the circumference with a pronounced curvature. In measurements performed with the same protocol as for clinical measurements, regions with different material properties (reflected by VBW) could be identified. This work demonstrates that within-specimen variations of material properties can be assessed with a technique available for in vivo measurements.

  20. Axial length in unilateral idiopathic central serous chorioretinopathy

    Directory of Open Access Journals (Sweden)

    Hoseok Moon

    2016-05-01

    Full Text Available AIM: To evaluate the axial length (AXL in unilateral idiopathic central serous chorioretinopathy (CSC. METHODS: This retrospective case-control study was comprised of a consecutive case series of 35 patients with acute unilateral idiopathic CSC, and age- and sex-matched 50 control eyes. AXL of both eyes of unilateral CSC patients and the control eyes were investigated. AXL was measured by ultrasonic biometry, and the adjusted AXL was calculated for CSC eyes as measured AXL plus differences of foveal thickness between CSC and normal fellow eyes in millimeters. The main outcome measures were comparison of AXL between CSC, fellow and control eyes. RESULTS: The mean age of 35 CSC patients was 45.5y, and 31 males were included. The adjusted AXL of CSC eyes was 23.52 mm, and the AXL of fellow eyes was 23.46 mm, and of control eyes 23.94 mm. The AXL of both CSC and fellow eyes were significantly shorter than control eyes (CSC vs control, P=0.044; fellow vs control, P=0.026. There was no statistically significant difference in AXL between CSC and fellow eyes. CONCLUSION: In unilateral idiopathic CSC, the AXL of CSC and fellow eyes are shorter than that of control eyes. Short AXL may be related with choroidal circulation abnormality in CSC.

  1. Flow and Performance Calculations of Axial Compressor near Stall Margin

    Science.gov (United States)

    Hwang, Yoojun; Kang, Shin-Hyoung

    2010-06-01

    Three-dimensional flows through a Low Speed Research Axial Compressor were numerically conducted in order to estimate the performance through unsteady and steady-state simulations. The first stage with the inlet guide vane was investigated at the design point to confirm that the rotor blade induced periodicity exists. Special attention was paid to the flow near the stall condition to inspect the flow behavior in the vicinity of the stall margin. The performance predicted under the steady-state assumption is in good agreement with the measured data. However, the steady-state calculations induce more blockage through the blade passage. Flow separations on the blade surface and end-walls are reduced when unsteady simulation is conducted. The negative jet due to the wake of the rotor blade periodically distorts the boundary layer on the surface of the stator blade and improves the performance of the compressor in terms of the pressure rise. The advantage of the unsteadiness increases as the flow rate reduces. In addition, the rotor tip leakage flow is forced downstream by the unsteadiness. Consequently, the behavior contributes to extending the range of operation by preventing the leakage flow from proceeding upstream near the stall margin.

  2. Axial Compressive Strength of Foamcrete with Different Profiles and Dimensions

    Directory of Open Access Journals (Sweden)

    Othuman Mydin M.A.

    2014-01-01

    Full Text Available Lightweight foamcrete is a versatile material; primarily consist of a cement based mortar mixed with at least 20% volume of air. High flow ability, lower self-weight, minimal requirement of aggregate, controlled low strength and good thermal insulation properties are a few characteristics of foamcrete. Its dry densities, typically, is below 1600kg/m3 with compressive strengths maximum of 15MPa. The ASTM standard provision specifies a correction factor for concrete strengths of between 14 and 42MPa to compensate for the reduced strength when the aspect height-to-diameter ratio of specimen is less than 2.0, while the CEB-FIP provision specifically mentions the ratio of 150 x 300mm cylinder strength to 150 mm cube strength. However, both provisions requirements do not specifically clarify the applicability and/or modification of the correction factors for the compressive strength of foamcrete. This proposed laboratory work is intended to study the effect of different dimensions and profiles on the axial compressive strength of concrete. Specimens of various dimensions and profiles are cast with square and circular cross-sections i.e., cubes, prisms and cylinders, and to investigate their behavior in compression strength at 7 and 28 days. Hypothetically, compressive strength will decrease with the increase of concrete specimen dimension and concrete specimen with cube profile would yield comparable compressive strength to cylinder (100 x 100 x 100mm cube to 100dia x 200mm cylinder.

  3. Ossification sequence and genetic patterning in the mouse axial skeleton.

    Science.gov (United States)

    Hautier, Lionel; Charles, Cyril; Asher, Robert J; Gaunt, Stephen J

    2014-12-01

    We provide novel data on vertebral ontogeny in the mouse, the mammalian model-of-choice for developmental studies. Most previous studies on ossification sequences in mice have focused on pooled elements of the spine (cervicals, thoracics, lumbars, sacrals, and caudals). Here, we contribute data on ossification sequences in the neural arches and centra to provide a comparative basis upon which to evaluate mammalian diversity of the axial skeleton. In attempt to explain the ossification pattern observed, we compared our observations with the phenotype of Cdx over-expresser mice. We use high-resolution X-ray microtomography and clearing and staining techniques to quantify the precise sequential ossification pattern of the mouse spine. We show that micro-CT scans perform better in all cases whereas clearing and staining exhibit sensitivity to the presence of semi-opaque tissue. We observe that the centra of wild-type mice always ossify after neural arches and that the ossification of the neural arches proceeds from two loci. The ossification of the centra appears more complex, especially in the neck where ossification is delayed and does not just follow the order of the vertebrae along the anterior-posterior axis. Our findings also suggest that Cdx genes' expression levels may be involved in the delayed ossification in the neck centra. © 2014 Wiley Periodicals, Inc.

  4. Evaluation of two dynamic axial fixators for large ruminants.

    Science.gov (United States)

    Singh, Gaj Raj; Aithal, Hari Prasad; Amarpal; Kinjavdekar, Prakash; Maiti, Swapan Kumar; Hoque, Mozammel; Pawde, Abhijit Motiram; Joshi, Hem Chandra

    2007-01-01

    To evaluate healing of a radial osteotomy repaired by application of dynamic axial fixation devices (DAF) in large ruminants. In vivo study of bone healing after application of 2 DAF types. Model I had 2 sidebars, each with a central cylindrical cuff (internally threaded) with 2 detachable connecting rods telescoping within the cuff. Model II had 2 side bars with 2 moveable clamps with multiple holes. Bull calves (n=8; aged, 1.5-2.0 years; weighing, 175-250 kg). A mid-diaphyseal radial osteotomy was repaired by use of a model I (n=4) or model II (n=4) DAF. Calves were monitored for weight bearing, stability of fixation, and radiographically for fracture reduction, alignment and healing at intervals for 6 months. Fixators were removed when there was radiographic evidence of healing. Both the fixators were well tolerated with free movement of adjacent joints. Fragment fixation was maintained until healing in all but 1 model I calf where failure occurred within 7 days. Model II DAF provided more rigid fixation as indicated by early full weight bearing and fracture healing with less callus formation. Functional recovery of repaired limbs occurred within 60 days in surviving calves. Both bilateral DAFs were easy to apply; however, the model II DAF provided better fixation. The model II DAF made of low carbon steel was economical and may be useful for treating long bone fractures in large ruminants.

  5. Spinal manipulation and spinal mobilization influence different axial sensory beds.

    Science.gov (United States)

    Bolton, Philip S; Budgell, Brian S

    2006-01-01

    Manipulation and mobilization are two forms of manual therapy commonly employed in the management of musculoskeletal disorders. Spinal manipulation and mobilization are often distinguished from one another by reference to certain biomechanical parameters such as peak force, duration and magnitude of translation. However, as of yet, there is relatively little research which distinguishes between them in terms of neurological mechanisms or clinical effectiveness. Theories concerning the mechanisms underlying the therapeutic effects of manipulation and mobilization commonly make reference to mechanical events such as the release of entrapped tissue or the disruption of intra-articular adhesions. Relatively less attention is given to neural effects. In this paper, we hypothesize that, at least in part, spinal manipulation preferentially influences a sensory bed which, in terms of anatomical location and function, is different from the sensory bed influenced by spinal mobilization techniques. More specifically, we hypothesize that manipulation may particularly stimulate receptors within deep intervertebral muscles, while mobilization techniques most likely affect more superficial axial muscles. In part, our rationale for this hypothesis is based on differences in mechanical advantage of the respective manual procedures on multi-segmental versus short intervertebral muscles.

  6. High temperature superconducting axial field magnetic coupler: realization and test

    Science.gov (United States)

    Belguerras, L.; Mezani, S.; Lubin, T.; Lévêque, J.; Rezzoug, A.

    2015-09-01

    Contactless torque transmission through a large airgap is required in some industrial applications in which hermetic isolation is necessary. This torque transmission usually uses magnetic couplers, whose dimension strongly depends on the airgap flux density. The use of high temperature superconducting (HTS) coils to create a strong magnetic field may constitute a solution to reduce the size of the coupler. It is also possible to use this coupler to replace a torque tube in transmitting the torque produced by a HTS motor to its load. This paper presents the detailed construction and tests of an axial field HTS magnetic coupler. Pancake coils have been manufactured from BSCCO tape and used in one rotor of the coupler. The second rotor is mainly composed of NdFeB permanent magnets. Several tests have been carried out showing that the constructed coupler is working properly. A 3D finite element (FE) model of the studied coupler has been developed. Airgap magnetic field and torque measurements have been carried out and compared to the FE results. It has been shown that the measured and the computed quantities are in satisfactory agreement.

  7. Lateral thoracic artery axial pattern flap in cats.

    Science.gov (United States)

    Benzioni, Hadas; Shahar, Ron; Yudelevich, Sigal; Shipov, Anna; Milgram, Joshua

    2009-01-01

    To describe the location of the lateral thoracic artery (LTA), determine dimensions of an axial pattern flap based on this artery, and report use of this flap in 2 cats. Ex vivo study and case reports. Cat cadavers (n=8); cats (n=2) with thoracic limb skin defects. Dissection of the LTA was carried out on 1 side of each cadaver and the contralateral side was used for injection studies. In 4 specimens, the LTA was cannulated and injected with positive contrast material and the flap was raised and radiographed. In 4 specimens, the flap was injected with methylene blue. Adequacy of flap injection was subjectively evaluated and leakage of methylene blue from the cut edge was noted. The cutaneous location of the LTA caudal to the triceps muscle was confirmed. Mean flap size was 8.7 cm x 15.5 cm for a mature, average-sized cat. Perfusion of the entire flap was demonstrated and viability of the flap was confirmed in 2 clinical cases. The LTA flap is useful for repair of skin defects of the brachium and antebrachium in cats. The LTA flap is an alternative technique for repair of skin defects involving the thoracic limb of cats.

  8. Axial and torsional stiffness of pediatric prosthetic feet.

    Science.gov (United States)

    Taboga, Paolo; Grabowski, Alena M

    2017-02-01

    Prosthetic stiffness likely affects the walking biomechanics of toddlers and children with leg amputations, but the actual stiffness values for prostheses are not reported by manufacturers or in standardized testing procedures. We measured axial (k A ) and torsional (k T ) stiffness from four brands of pediatric prosthetic feet (Trulife, Kingsley Mfg. Co., TRS Incorporated, and College Park Industries) over a range of foot sizes. We applied forces and torques onto prostheses with a materials testing machine that replicated those exhibited in vivo by using the kinetics measured from four non-amputee toddlers (2-3years) during walking. Across brands, k A averaged 35.2kN/m during heel loading, was more stiff during midfoot loading (121.8kN/m, Pfeet. Plantarflexion torsional stiffness (k T1 ), was not statistically different across brands. For every 1cm increase in foot size, k T1 increased 0.16kN·m/rad (Pfeet should be publically reported to health practitioners to ensure evidence-based decisions and meet the specific needs of each patient with a leg amputation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Action potential propagation in transverse-axial tubular system is impaired in heart failure.

    Science.gov (United States)

    Sacconi, Leonardo; Ferrantini, Cecilia; Lotti, Jacopo; Coppini, Raffaele; Yan, Ping; Loew, Leslie M; Tesi, Chiara; Cerbai, Elisabetta; Poggesi, Corrado; Pavone, Francesco S

    2012-04-10

    The plasma membrane of cardiac myocytes presents complex invaginations known as the transverse-axial tubular system (TATS). Despite TATS's crucial role in excitation-contraction coupling and morphological alterations found in pathological settings, TATS's electrical activity has never been directly investigated in remodeled tubular networks. Here we develop an ultrafast random access multiphoton microscope that, in combination with a customly synthesized voltage-sensitive dye, is used to simultaneously measure action potentials (APs) at multiple sites within the sarcolemma with submillisecond temporal and submicrometer spatial resolution in real time. We find that the tight electrical coupling between different sarcolemmal domains is guaranteed only within an intact tubular system. In fact, acute detachment by osmotic shock of most tubules from the surface sarcolemma prevents AP propagation not only in the disconnected tubules, but also in some of the tubules that remain connected with the surface. This indicates that a structural disorganization of the tubular system worsens the electrical coupling between the TATS and the surface. The pathological implications of this finding are investigated in failing hearts. We find that AP propagation into the pathologically remodeled TATS frequently fails and may be followed by local spontaneous electrical activity. Our findings provide insight on the relationship between abnormal TATS and asynchronous calcium release, a major determinant of cardiac contractile dysfunction and arrhythmias.

  10. Retrieving the axial position of fluorescent light emitting spots by shearing interferometry

    Science.gov (United States)

    Schindler, Johannes; Schau, Philipp; Brodhag, Nicole; Frenner, Karsten; Osten, Wolfgang

    2016-12-01

    A method for the depth-resolved detection of fluorescent radiation based on imaging of an interference pattern of two intersecting beams and shearing interferometry is presented. The illumination setup provides the local addressing of the excitation of fluorescence and a coarse confinement of the excitation volume in axial and lateral directions. The reconstruction of the depth relies on the measurement of the phase of the fluorescent wave fronts. Their curvature is directly related to the distance of a source to the focus of the imaging system. Access to the phase information is enabled by a lateral shearing interferometer based on a Michelson setup. This allows the evaluation of interference signals even for spatially and temporally incoherent light such as emitted by fluorophors. An analytical signal model is presented and the relations for obtaining the depth information are derived. Measurements of reference samples with different concentrations and spatial distributions of fluorophors and scatterers prove the experimental feasibility of the method. In a setup optimized for flexibility and operating in the visible range, sufficiently large interference signals are recorded for scatterers placed in depths in the range of hundred micrometers below the surface in a material with scattering properties comparable to dental enamel.

  11. Effects of energetic coherent motions on the power and wake of an axial-flow turbine

    Science.gov (United States)

    Chamorro, L. P.; Hill, C.; Neary, V. S.; Gunawan, B.; Arndt, R. E. A.; Sotiropoulos, F.

    2015-05-01

    A laboratory experiment examined the effects of energetic coherent motions on the structure of the wake and power fluctuations generated by a model axial-flow hydrokinetic turbine. The model turbine was placed in an open-channel flow and operated under subcritical conditions. The incoming flow was locally perturbed with vertically oriented cylinders of various diameters. An array of three acoustic Doppler velocimeters aligned in the cross-stream direction and a torque transducer were used to collect high-resolution and synchronous measurements of the three-velocity components of the incoming and wake flow as well as the turbine power. A strong scale-to-scale interaction between the large-scale and broadband turbulence shed by the cylinders and the turbine power revealed how the turbulence structure modulates the turbine behavior. In particular, the response of the turbine to the distinctive von Kármán-type vortices shed from the cylinders highlighted this phenomenon. The mean and fluctuating characteristics of the turbine wake are shown to be very sensitive to the energetic motions present in the flow. Tip vortices were substantially dampened and the near-field mean wake recovery accelerated in the presence of energetic motions in the flow. Strong coherent motions are shown to be more effective than turbulence levels for triggering the break-up of the spiral structure of the tip-vortices.

  12. Application of ultimate limit state design for axially loaded single piles in Egyptian geotechnical practice

    Directory of Open Access Journals (Sweden)

    Yasser M. El-Mossallamy

    2017-08-01

    Full Text Available For a long time, the framework of geotechnical design in Egypt has been based mainly on Working Stress Design (WSD philosophy with the global safety concept as presented in the current version of the Egyptian Code of Practice for Soil Mechanics and Foundations Design and Construction [1]. This design philosophy is supported by long-term experience, considering local experiences and is adopted to fulfill the required safety margin. Limit State Design (LSD philosophy, on the other side, has already been applied for the design of reinforced concrete structures as introduced in the Egyptian Code of Practice for the Design and Construction of Reinforced Concrete Structures [2]. Applying LSD for superstructure and WSD for foundations often results in design misleading because of the incompatibility between the two design philosophies. Accordingly, implementation of LSD philosophy for geotechnical designs in Egypt has become mandatory and the transition to this new design philosophy of LSD should be as smooth and gradual as possible to allow for a better acceptance by the Egyptian geotechnical community. LSD philosophy using partial safety factors has been applied worldwide using two different approaches; factored strength approach and factored resistance approach. During this study, resistance reduction factors are calibrated on the basis of calibration-by-fitting technique, to be used with factored resistance approach for axially loaded single piles. The calibrated resistance reduction factors from this study are found to be relatively consistent with those values adopted in other geotechnical design codes worldwide.

  13. Shape Manifestation of Respiration in the Axial System

    Directory of Open Access Journals (Sweden)

    Eliška Slawiková

    2014-07-01

    Full Text Available Shape Manifestation of Respiration in the Axial System The aim of the study was to evaluate the effect of respiration on the shape changes of the axial system. Our approach focuses more on the analysis of respiratory function and their implementation within the complex axial system – the trunk. The results of this pilot study will use as evidence for further study of relationship between respiration and physiotherapy. Now we are looking for an answer to the question, at what level of the human body reflected the influence of respiration and its use in physiotherapy. This pilot study was attended by two women and one man aged 25–40 years, who were not selected for the study according to predetermined conditions. The same characteristic features of all three prarticipants were sedentary job connected with excessive mental strain, occasional low back pain (usually after a long sitting and the absence of acute or chronic respiratory diseases. Another common feature of the participants was the absence of structural changes in the spine. During the experiment was monitored maximum inhalation and maximum exhalation, and respiratory maneuver Kapalabhati, often used as one of the basic yoga breathing exercises. To detect trunk movement during the respiratory maneuver, we opted for a Qualysis – 3D torso topography. At the same time spirometer panned changes in volume over time, both exhaled and inhaled air. The purpose of this study was to assess symptoms and implementation of respiratory maneuvers in the axial system, particularly the chest and abdominal area. During the experiment, we followed the differences in reaction of the chest and abdomen in respiratory maneuver in the direction vertical, antero-posterior and lateral. The difference in these indicators at different phases of the respiratory maneuver confirms our assumption of the possibility of influencing the selected folders axial system through appropriately selected respiratory maneuver

  14. Synthesis of Ruthenium(III Phthalocyanine with Di-axial Bromo Ligands - A Promising Molecular Conductor with Giant Negative Magnetoresistance

    Directory of Open Access Journals (Sweden)

    Mario A.V. Gamboa

    2015-01-01

    Full Text Available The electron transport of Phthalocyanines (Pc with central metal and di-axial ligands (such as FeIII(PcL2; where L = CN, Cl, Br originates from its intermolecular Pc π-π orbital overlap while its giant negative magnetoresistance (GNMR arises from its intramolecular Pc-π(HOMO and Fe-d (s=1/2 interaction. However, the π-d interaction tends to localize itinerant electrons resulting in the decrease in the conductivity of the FeIII(PcL2 series compared to the non-magnetic CoIII(PcL2 where π-d interaction is absent. More so, the axial ligand field energy of the FeIII(PcL2 system is found to have the ability to proportionally modulate the π-d interaction. In reference thereof, theoretical calculations point that isostructural RuIII(PcBr2 would provide the best balance of π-d orbital energy interplay. That is, RuIII(PcBr2 is expected to be a molecule with high electrical conductivity and GNMR which would make it an ideal magnetic molecular conductor. This paper reports on the synthesis of RuIII(PcBr2.

  15. Prediction of secular acceleration of axial rotation of Mars

    Science.gov (United States)

    Barkin, Yu. V.

    2009-04-01

    Secular motion of the Earth pole and non-tidal acceleration of its diurnal rotation have obtained rather precise explanation with the help of simple one-point model of the directed transport of fluid masses from a southern hemisphere in northern hemisphere with the general direction, given by geocentric axis OP directed to pole P with coordinates 700N, 10403 E[1]. The another generalized model represents a system of two material points with masses m2 and m1, located on surface of the Earth at poles of geocentric axis OP. Masses are linearly changed in the time with velocities [2]: ṁ2 = 0.179 × 1015kg/yrand ṁ1 = 0.043 × 1015kg/yr. A reduction of fluid masses of the appropriate thin spherical layer of the Earth correspond to secular increasing of masses of model points. The specified model has allowed to explain values of fundamental geodynamic parameters observably and determined during decades: a direction and velocity of drift of a pole of the Earth; value of non-tidal acceleration of axial rotation; to explain a secular variations of coefficients of the second, third, fourth, sixth and eighth zonal harmonics of a geopotential; coefficients of secular changes of a surface of ocean for the last approximately 150 years; a direction of secular drift of a geocenter and other planetary phenomena [3]. The role of the angular momentum of redistributed masses of the Earth in rotation of the Earth appeared not essential at the given stage of researches. On the essence the offered model has semi-empirical character as it bases on values of velocities of change of masses of points and the given position of axis OP. For their determination and estimations the part of the observant data was used, and other parameters were designed under analytical formulas. The obtained results have precisely confirmed competency and affectivity of geodynamic model [4] about existence of secular drift of a liquid core along radial direction OP with velocity about 2.6 cm/yr in the

  16. Polymer Physics Prize Lecture: Self-assemblies of Giant Molecular Shape Amphiphiles as a New Platform for Engineering Structures with Sub-Nanometer Feature Sizes

    Science.gov (United States)

    Cheng, Stephen Z. D.

    2013-03-01

    Utilizing nano-building blocks rather than atoms to construct and engineer new structures is a fresh approach to design and develop functional materials for the purpose of transferring and amplifying microscopic functionality to macroscopic materials' property. As one of the important elements of these nano-building blocks, giant molecular shape amphiphiles (GMSAs) provide a latest platform for generating self-assembled ordered structures at nanometer scale, which are stabilized by collective physical bonds (such as collective hydrogen bonding). In this talk, two topics will be focused on. First, composed of functionalized hydrophilic molecular nanoparticles as the heads with rigid shape and fixed volume, and tethered polymer chains as the tails (such as giant molecular surfactants and lipids and other topologies), these GMSAs of various architectures can self-assemble into highly diversified, thermodynamically stable microstructures at sub-10 nm length scale in the bulk, thin film and solution states. Second, GMSAs could also be constructed solely from nanoparticles interconnected via different numbers of the rigid linkages in specific symmetry, simulating the overall shapes of small molecules but with sizes that are one-order of magnitude larger in length and three-order of magnitude larger in volume. Giant crystal structures can then be obtained from this class of ``giant molecules'' via supramolecular crystallization. These findings are not only scientifically intriguing in understanding the physical principles underlying their self-assembly, but also technologically relevant in industrial applications.

  17. Elastic recoil atomic spectroscopy of light elements with sub-nanometer depth resolution; Elastische Rueckstossatomspektrometrie leichter Elemente mit Subnanometer-Tiefenaufloesung

    Energy Technology Data Exchange (ETDEWEB)

    Kosmata, Marcel

    2011-06-30

    In this thesis the QQDS magnetic spectrometer that is used for high resolution ion beam analysis (IBA) of light elements at the Helmholtz-Zentrum Dresden-Rossendorf is presented for the first time. In addition all parameters are investigated that influence the analysis. Methods and models are presented with which the effects can be minimised or calculated. There are five focal points of this thesis. The first point is the construction and commissioning of the QQDS magnetic spectrometer, the corresponding scattering chamber with all the peripherals and the detector, which is specially developed for high resolution elastic recoil detection. Both the reconstructed spectrometer and the detector were adapted to the specific experimental conditions needed for high-resolution Ion beam analysis of light elements and tested for routine practice. The detector consists of two components. At the back end of the detector a Bragg ionization chamber is mounted, which is used for the particle identification. At the front end, directly behind the entrance window a proportional counter is mounted. This proportional counter includes a highresistance anode. Thus, the position of the particles is determined in the detector. The following two points concern fundamental studies of ion-solid interaction. By using a magnetic spectrometer the charge state distribution of the particles scattered from the sample after a binary collision is both possible and necessary for the analysis. For this reason the charge states are measured and compared with existing models. In addition, a model is developed that takes into account the charge state dependent energy loss. It is shown that without the application of this model the depth profiles do not correspond with the quantitative measurements by conventional IBA methods and with the thickness obtained by transmission electron microscopy. The second fundamental ion-solid interaction is the damage and the modification of the sample that occurs during heavy ion irradiation. It is shown that the used energies occur both electronic sputtering and electronically induced interface mixing. Electronic sputtering is minimised by using optimised beam parameters. For most samples the effect is below the detection limit for a fluence sufficient for the analysis. However, the influence of interface mixing is so strong that it has to be included in the analysis of the layers of the depth profiles. It is concluded from these studies that at the Rossendorf 5 MV tandem accelerator chlorine ions with an energy of 20 MeV deliver the best results. In some cases, such as the analysis of boron, the energy must be reduced to 6.5 MeV in order to retain the electronic sputtering below the detection limit. The fourth focus is the study of the influence of specific sample properties, such as surface roughness, on the shape of a measured energy spectra and respectively on the analysed depth profile. It is shown that knowledge of the roughness of a sample at the surface and at the interfaces for the analysis is needed. In addition, the contribution parameters limiting the depth resolution are calculated and compared with the conventional ion beam analysis. Finally, a comparison is made between the highresolution ion beam analysis and complementary methods published by other research groups. The fifth and last focus is the analysis of light elements in ultra thin layers. All models presented in this thesis to reduce the influence of beam damage are taken into account. The dynamic non-equilibrium charge state is also included for the quantification of elements. Depth profiling of multilayer systems is demonstrated for systems consisting of SiO{sub 2}-Si{sub 3}N{sub 4}O{sub x}-SiO{sub 2} on silicon, boron implantation profiles for ultra shallow junctions and ultra thin oxide layers, such as used as high-k materials.

  18. Easy probability estimation of the diagnosis of early axial spondyloarthritis by summing up scores.

    Science.gov (United States)

    Feldtkeller, Ernst; Rudwaleit, Martin; Zeidler, Henning

    2013-09-01

    Several sets of criteria for the diagnosis of axial SpA (including non-radiographic axial spondyloarthritis) have been proposed in the literature in which scores were attributed to relevant findings and the diagnosis requests a minimal sum of these scores. To quantitatively estimate the probability of axial SpA, multiplying the likelihood ratios of all relevant findings was proposed by Rudwaleit et al. in 2004. The objective of our proposal is to combine the advantages of both, i.e. to estimate the probability by summing up scores instead of multiplying likelihood ratios. An easy way to estimate the probability of axial spondyloarthritis is to use the logarithms of the likelihood ratios as scores attributed to relevant findings and to use the sum of these scores for the probability estimation. A list of whole-numbered scores for relevant findings is presented, and also threshold sum values necessary for a definite and for a probable diagnosis of axial SpA as well as a threshold below which the diagnosis of axial spondyloarthritis can be excluded. In a diagram, the probability of axial spondyloarthritis is given for sum values between these thresholds. By the method proposed, the advantages of both, the easy summing up of scores and the quantitative calculation of the diagnosis probability, are combined. Our method also makes it easier to estimate which additional tests are necessary to come to a definite diagnosis.

  19. Acute pulmonary embolism: Comparison of standard axial MDCT with paddlewheel technique

    Energy Technology Data Exchange (ETDEWEB)

    Brader, Peter [Department of Radiology, Medical University Graz, Auenbruggerplatz 9, A-8036 Graz (Austria)], E-mail: peter.brader@meduni-graz.at; Schoellnast, Helmut; Deutschmann, Hannes A.; Thimary, Felix; Schaffler, Gottfried; Reittner, Pia [Department of Radiology, Medical University Graz, Auenbruggerplatz 9, A-8036 Graz (Austria)

    2008-04-15

    Purpose: The purpose of this study was to evaluate the ability of rotated paddlewheel reformations for the detection of central and peripheral pulmonary embolism (PE) compared to standard axial multi detector CT (MDCT) images. Material and methods: CT scans of 35 patients with PE were reviewed by three independent readers for the detection of pulmonary emboli using standard axial CT scans and reformatted paddlewheel technique. All images were evaluated in random order. MDCT examinations were performed with a collimation of 1.25 mm, a pitch of six and a reconstruction interval of 0.8 mm. For each patient MIP were reformatted by using a paddlewheel arrangement with 5 mm slab thickness and 5 deg. rotation. Standard of reference for PE was a consensus reading of the axial images by all three readers. Results: The overall sensitivity for the axial images for the three readers ranged between 91% and 96%; for paddlewheel reformations from 78% to 83%; the specificity for both methods was 98-99%. Inter- and intraobserver agreement was also higher for axial images than for paddlewheel reformations. Conclusion: Comparing standard axial MDCT scans and reformatted paddlewheel images no significant difference for the detection of central PE was found, whereas for the detection of peripheral emboli standard axial images showed a significant higher percentage of detecting PE than paddlewheel reformations.

  20. COMPARATIVE ANALYSIS OF ACTIVE POWER LOSSES OF INDUCTION MOTORS WITH CYLINDRICAL AND AXIAL AIR GAPS

    Directory of Open Access Journals (Sweden)

    А.А. Stavinskii

    2015-11-01

    Full Text Available Purpose. To find the analytical expressions of determining the optimum geometric dimensions by criteria of the losses minimum of axial field squirrel-cage induction motors and to compare traditional and axial field motors. Methodology. We have applied the method of the relative indications of the technical level with relative controlled variables. We have used the approximation of the experimental dependence of the distribution of the induction in the air gap and the integral averaging of the magnetic flux. Results. We have developed the mathematical model for determining the optimum geometric dimensions by criteria of the losses minimum of the active part of axial field squirrel-cage induction motors taking into account the radial distribution of the induction in the air gap and teeth. We have considered the comparative analysis of the indications of active power losses of traditional and axial designs of electromagnetic equivalent motors. Originality. For the first time we have created the mathematical model of the active power losses of the active part of axial field squirrel-cage induction motors with the uneven distribution of the magnetic flux in the core and investigated the effect of the geometric relationships on the energy efficiency of axial field motors. Practical value. Based on the superior parametric compatibility and the high energy efficiency of axial motors the expediency of replacing traditional induction motors to axial field induction motors has been proved in the special drives, which operates in continuous duty. Also obtained by simulation optimal geometric relationships of the magnetic circuit can be used in the manufacture and design of axial motors by criteria of the losses minimum.

  1. Experimental Investigations on Axially and Eccentrically Loaded Masonry Walls

    Science.gov (United States)

    Keshava, Mangala; Raghunath, Seshagiri Rao

    2017-12-01

    In India, un-reinforced masonry walls are often used as main structural components in load bearing structures. Indian code on masonry accounts the reduction in strength of walls by using stress reduction factors in its design philosophy. This code was introduced in 1987 and reaffirmed in 1995. The present study investigates the use of these factors for south Indian masonry. Also, with the gaining popularity in block work construction, the aim of this study was to find out the suitability of these factors given in the Indian code to block work masonry. Normally, the load carrying capacity of masonry walls can be assessed in three ways, namely, (1) tests on masonry constituents, (2) tests on masonry prisms and (3) tests on full-scale wall specimens. Tests on bricks/blocks, cement-sand mortar, brick/block masonry prisms and 14 full-scale brick/block masonry walls formed the experimental investigation. The behavior of the walls was investigated under varying slenderness and eccentricity ratios. Hollow concrete blocks normally used as in-fill masonry can be considered as load bearing elements as its load carrying capacity was found to be high when compared to conventional brick masonry. Higher slenderness and eccentricity ratios drastically reduced the strength capacity of south Indian brick masonry walls. The reduction in strength due to slenderness and eccentricity is presented in the form of stress reduction factors in the Indian code. These factors obtained through experiments on eccentrically loaded brick masonry walls was lower while that of brick/block masonry under axial loads was higher than the values indicated in the Indian code. Also the reduction in strength is different for brick and block work masonry thus indicating the need for separate stress reduction factors for these two masonry materials.

  2. Case report: Physical therapy management of axial dystonia.

    Science.gov (United States)

    Voos, Mariana Callil; Oliveira, Tatiana de Paula; Piemonte, Maria Elisa Pimentel; Barbosa, Egberto Reis

    2014-01-01

    Few studies have described physical therapy approaches to provide functional independence and reduce pain in individuals with dystonia. This report describes the physical therapy treatment of a 46-year-old woman diagnosed with idiopathic segmental axial dystonia. For two years, the patient was treated with kinesiotherapy (active and resisted movements and stretching of neck and trunk muscles), abdominal taping (kinesiotaping techniques), functional training, and sensory tricks. She was assessed with parts I, II and III of Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS-I, TWSTRS-II and TWSTRS-III), Berg Balance Scale (BBS), Six-Minute Walk Test (6-MWT), and the motor domain of Functional Independence Measure (FIM-motor) before and after the two-year treatment and after the one year follow-up. Postural control and symmetry improved (TWSTRS-I: from 30 to 18), functional independence increased (TWSTRS-II: from 27 to 15; BBS: from 36 to 46; 6-MWT: from 0 to 480 meters (m); FIM-motor: from 59 to 81), and the pain diminished (TWSTRS-III: from 12 to 5). The functional improvement was retained after one year (TWSTRS-I: 14/35; TWRTRS-II: 12/30; TWRTRS-III: 5/20; BBS: 48/56; 6-MWT: 450 m; FIM-motor: 81/91). This program showed efficacy on providing a better control of the dystonic muscles and thus the doses of botulinum toxin needed to treat them could be reduced. Outcomes support the therapeutic strategies used to deal with this type of dystonia.

  3. Recent developments of axial flow compressors under transonic flow conditions

    Science.gov (United States)

    Srinivas, G.; Raghunandana, K.; Satish Shenoy, B.

    2017-05-01

    The objective of this paper is to give a holistic view of the most advanced technology and procedures that are practiced in the field of turbomachinery design. Compressor flow solver is the turbulence model used in the CFD to solve viscous problems. The popular techniques like Jameson’s rotated difference scheme was used to solve potential flow equation in transonic condition for two dimensional aero foils and later three dimensional wings. The gradient base method is also a popular method especially for compressor blade shape optimization. Various other types of optimization techniques available are Evolutionary algorithms (EAs) and Response surface methodology (RSM). It is observed that in order to improve compressor flow solver and to get agreeable results careful attention need to be paid towards viscous relations, grid resolution, turbulent modeling and artificial viscosity, in CFD. The advanced techniques like Jameson’s rotated difference had most substantial impact on wing design and aero foil. For compressor blade shape optimization, Evolutionary algorithm is quite simple than gradient based technique because it can solve the parameters simultaneously by searching from multiple points in the given design space. Response surface methodology (RSM) is a method basically used to design empirical models of the response that were observed and to study systematically the experimental data. This methodology analyses the correct relationship between expected responses (output) and design variables (input). RSM solves the function systematically in a series of mathematical and statistical processes. For turbomachinery blade optimization recently RSM has been implemented successfully. The well-designed high performance axial flow compressors finds its application in any air-breathing jet engines.

  4. Regionalization of axial skeleton in the lungfish Neoceratodus forsteri (Dipnoi).

    Science.gov (United States)

    Johanson, Zerina; Sutija, Margareta; Joss, Jean

    2005-05-15

    Differentiation of the axial skeleton into distinct regions, once thought to be characteristic of the Tetrapoda, also occurs in the actinopterygian Danio rerio. In these taxa, the boundary between the cervical-thoracic regions correlates with Hoxc6 expression and morphological features such as position of the pectoral fin and associated nerves, and the absence of ribs. In the lungfish Neoceratodus, a member of the extant sister taxon to the Tetrapoda, the first vertebral element to chondrify is situated well posterior to the skull, developing from somites 6 and 7 (6/7) and associated with an enlarged cranial rib and nerves innervating the pectoral fin. Two vertebral elements develop later and more anteriorly, associated with somites 4/5 and 5/6. These three elements become incorporated into the occipital region of the skull during Neoceratodus ontogeny, until the cranial rib itself articulates to the rear of the skull. These features of early development indicate a regionalization of the Neoceratodus vertebral column: the cranial rib marks the boundary between the cervical and thoracic regions, the two more anterior vertebrae lacking ribs represent the cervical region, while somites 1-4 (cranial half), lacking any vertebral development, represent the occipital region. However, the cervical region of the vertebral column is effectively lost during ontogeny of Neoceratodus. A recognizable cervical region in the tetrapod vertebral column, as in zebrafish, suggests that cervical vertebrae are not incorporated into the skull but maintained as distinct elements of the column, representing an important shift in relative developmental timing and the influence of heterochrony in this region during the fish-tetrapod transition. Copyright 2005 Wiley-Liss, Inc

  5. Measurement technique of calcaneal varus from axial view radiograph

    Directory of Open Access Journals (Sweden)

    Thossart Harnroongroj

    2015-01-01

    Full Text Available Background: Medial displaced posterior calcaneal tubercle creates varus deformity of an intraarticular calcaneal fracture. The fracture involves posterior calcaneal facet and the calcaneal body so we developed a measurement technique representing the angle between posterior facet and long axis of calcaneus using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references to obtain calcaneal varus angle. Materials and Methods: 52 axial view calcaneal radiographs of 26 volunteers were studied. Angles between posterior facet and long axis of calcaneus were measured using the measurements 1 and 2. Angle of measurement 1, as gold standard, was obtained from long axis and posterior facet of calcaneus whereas measurement 2 was obtained from a line, perpendicular to apex curve of lateral cortex of the lateral malleolus and a line parallel to the longitudinal bone trabeculae of posterior calcaneal tubercle. No more than 3° of difference in the angle of both measurements was accepted. Reliability of the measurement 2 was statistically tested. Results: Angles of measurement 1 and 2 were 90.04° ± 4.00° and 90.58° ± 3.78°. Mean of different degrees of both measurements was 0.54° ± 2.31° with 95% of confidence interval: 0.10°-1.88°. The statistical analysis of measurement 1 and 2 showed more than 0.75 of ICC and 0.826 of Pearson correlation coefficient. Conclusion: Technique of measurement 2 using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references has strong reliability for representing the angle between long axis and posterior facet of calcaneus to achieve calcaneal varus angle.

  6. Axial synergies in parkinsonian patients during voluntary trunk bending.

    Science.gov (United States)

    Alexandrov; Aurenty; Massion; Mesure; Viallet

    1998-10-01

    During upper trunk movements, the axial kinematic synergies (opposite movements of upper and lower segments) preserve the balance by minimizing the antero-posterior center of gravity (CG) shift due to the movement. Forward and backward upper trunk movements were analyzed in a population of parkinsonian patients (PD) that were subject to falling, in order to determine whether an impaired control of the kinematic synergies might explain the falling. Ten PD (stage III-IV of the Hoehn and Yahr classification; Hoehn MM, Yahr MD. Parkinsonism: onset, progression and mortality. Neurology 1967;17;427-432) were compared to seven age-matched control subjects (CS). Kinematic analysis and force platform recordings were carried out. Principal Component (PC) analysis was performed to measure the coupling between hip, knee and ankle joint angles during the movement. (1) In both PD and CS, the first principal component (PC1) was found to account for 98% or more of the joint angles changes, which indicates that there exists a strong coupling between the angles during the movement; however, the part of the movement not accounted for by PC1 was twice as high in PD as in CS. (2) The intertrial variability between the angle ratios was about twice as high in PD as in CS. (3) The absolute value of the antero-posterior CG shift occurring during the movement significantly increased in PD in the case of backward movements, both fast and slow. (4) As a high correlation was found between actual CG shift and its estimation based on the observed interjoint coordination, the increased CG shift in PD was related to unproper set of ratios between joint angles. It was concluded that the control of the kinematic synergy is preserved on the whole in PD, with an increased variability and unproper set of the ratios between joint angular changes. This may lead to CG shifts to beyond the support surface, especially in backward bending. Copyright 1998 Elsevier Science B.V.

  7. Modelling the behaviour of ingot axial defects under open die forging

    Science.gov (United States)

    Rutskii, D. V.; Stjagin, A. N.; Zyuban, N. A.; Gamanyuk, S. B.

    2017-02-01

    The paper reports findings on mathematical modelling of ingots of different geometry. It is established that V-shaped cracks concentrated in the ingot bottom are gradually removed through upset, while arch-shaped cracks located around the sedimentation cone top open up. A computer simulation made it possible to calculate efficient deformations in the workpiece axial zone. An alteration of the ingot geometry leads to an increase in efficient deformation and, consequently, a better treatment of axial areas and elimination of the axial defects of the ingot metal.

  8. Beyond axial symmetry: An improved class of models for global data

    KAUST Repository

    Castruccio, Stefano

    2014-03-01

    An important class of models for data on a spherical domain, called axially symmetric, assumes stationarity across longitudes but not across latitudes. The main aim of this work is to introduce a new and more flexible class of models by relaxing the assumption of longitudinal stationarity in the context of regularly gridded climate model output. In this investigation, two other related topics are discussed: the lack of fit of an axially symmetric parametric model compared with a non-parametric model and to longitudinally reversible processes, an important subclass of axially symmetric models.

  9. Mapping electrostatic profiles across axial p-n junctions in Si nanowires using off-axis electron holography

    Science.gov (United States)

    Gan, Zhaofeng; Perea, Daniel E.; Yoo, Jinkyoung; Tom Picraux, S.; Smith, David J.; McCartney, Martha R.

    2013-10-01

    Si nanowires (NWs) with axial p-n junctions were grown by the vapor-liquid-solid method. Transmission electron microscopy and electron holography were used to characterize the microstructure and electrostatic properties. Measurement of the potential profile showed the presence of a p-n junction with a height of 1.0 ± 0.3 V. A Schottky barrier was observed at the end of the NW due to the Au catalyst particle. Comparison with simulations indicated dopant concentrations of 1019 cm-3 for donors and 1017 cm-3 for acceptors. These results confirm the benefit of combining off-axis electron holography with simulations for determining localized information about the electrically active dopant distributions in nanowire structures.

  10. Mapping Electrostatic Profiles Across Axial p-n Junctions in Si Nanowires using Off-Axis Electron Holography

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Zhaofeng; Perea, Daniel E.; Yoo, Jinkyoung; Picraux, Samuel T.; Smith, David J.; Mccartney, Martha R.

    2013-10-07

    Si nanowires (NWs) with axial p-n junctions were grown by the vapor-liquid-solid method. Transmission electron microscopy and electron holography were used to characterize the microstructure and electrostatic properties. Measurement of the potential profile showed the presence of a p-n junction with a height of 1.0±0.3V. A Schottky barrier was observed at the end of the NW due to the Au catalyst particle. Comparison with simulations indicated dopant concentrations of 1019cm-3 for donors and 1017cm-3 for acceptors. These results confirm the benefit of combining off-axis electron holography with simulations for determining localized information about the electrically active dopant distributions in nanowire structures.

  11. Local Foods, Local Places Toolkit

    Science.gov (United States)

    Toolkit to help communities that want to use local foods to spur revitalization. The toolkit gives step-by-step instructions to help communities plan and host a workshop and create an action plan to implement.

  12. Statically determined slip-line field solution for the axial forming force estimation in the radial-axial ring rolling process

    Science.gov (United States)

    Quagliato, Luca; Berti, Guido A.

    2017-10-01

    In this paper, a statically determined slip-line solution algorithm is proposed for the calculation of the axial forming force in the radial-axial ring rolling process of flat rings. The developed solution is implemented in an Excel spreadsheet for the construction of the slip-line field and the calculation of the pressure factor to be used in the force model. The comparison between analytical solution and authors' FE simulation allows stating that the developed model supersedes the previous literature ones and proves the reliability of the proposed approach.

  13. Locals Collection

    Directory of Open Access Journals (Sweden)

    Stephen Hastings-King

    2010-03-01

    Full Text Available A locals collection is a set of parameters that are used to delimit data-mining operations. This piece uses a collection of locals from around Essex Massachusetts to shape and delimit an interrogation of post-reality in contemporary America. It explores the notion of crisis, the possibility of a crisis of empire that may or may not emerge in a media-space that does not allow crisis of empire to be mentioned and relations this maybe-crisis to the various levels of economic dysfunction that have become evident since late 2008. But mostly this piece explores ways in which particular stories about particular people do and do not link/link to these larger-scale narratives. This is the first of a potential series of locals collections that will mine the American post-real.

  14. Desarrollo local

    Directory of Open Access Journals (Sweden)

    Luciano Palmitesta

    2001-12-01

    Full Text Available Tras explicar la génesis del concepto de desarrollo y a quien se le aplica la necesidad de desarrollarse, el autor de este ensayo hace un recorrido por las escuelas más representativas de pensamiento sobre el tema. A continuación, entra a reflexionar el concepto de lo local y de sociedad local y sus elementos. En la segunda parte, se analiza la Economía Local y se hace un intento de aplicar esta teoría a la realidad nicaragüense. En esta parte se examinan las diferentes formas empresariales más comunes en Nicaragua. Igualmente, se estudian las dificultades y ventajas de este tipo de empresas en un mundo globalizado y se plantean algunos posibles mecanismos para afrontar los problemas. El trabajo cierra con algunas breves conclusiones.

  15. Investigation of Axial Strengthened Reinforced Concrete Columns under Lateral Blast Loading

    National Research Council Canada - National Science Library

    Mohammad Esmaeilnia Omran; Somayeh Mollaei

    2017-01-01

    .... Therefore, an experimental explosion loading has been done on RC members by the authors. Four RC components, with identical geometry and material, with and without axial load were imposed to air blast...

  16. Empirical correlations for axial dispersion coefficient and Peclet number in fixed-bed columns.

    Science.gov (United States)

    Rastegar, Seyed Omid; Gu, Tingyue

    2017-03-24

    In this work, a new correlation for the axial dispersion coefficient was obtained using experimental data in the literature for axial dispersion in fixed-bed columns packed with particles. The Chung and Wen correlation, the De Ligny correlation are two popular empirical correlations. However, the former lacks the molecular diffusion term and the latter does not consider bed voidage. The new axial dispersion coefficient correlation in this work was based on additional experimental data in the literature by considering both molecular diffusion and bed voidage. It is more comprehensive and accurate. The Peclet number correlation from the new axial dispersion coefficient correlation on the average leads to 12% lower Peclet number values compared to the values from the Chung and Wen correlation, and in many cases much smaller than those from the De Ligny correlation. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Controllable rectification of the axial expansion in the thermally driven artificial muscle

    Science.gov (United States)

    Yue, Donghua; Zhang, Xingyi; Yong, Huadong; Zhou, Jun; Zhou, You-He

    2015-09-01

    At present, the concept of artificial muscle twisted by polymers or fibers has become a hot issue in the field of intelligent material research according to its distinguishing advantages, e.g., high energy density, large-stroke, non-hysteresis, and inexpensive. The axial thermal expansion coefficient is an important parameter which can affect its demanding applications. In this letter, a device with high accuracy capacitive sensor is constructed to measure the axial thermal expansion coefficient of the twisted carbon fibers and yarns of Kevlar, and a theoretical model based on the thermal elasticity and the geometrical features of the twisted structure are also presented to predict the axial expansion coefficient. It is found that the calculated results take good agreements with the experimental data. According to the present experiment and analyses, a method to control the axial thermal expansion coefficient of artificial muscle is proposed. Moreover, the mechanism of this kind of thermally driven artificial muscle is discussed.

  18. [Progress on atlanto-axial pedicle screw fixation through posterior approach].

    Science.gov (United States)

    Li, Guo-Qing; Ma, Wei-Hu; Liu, Guan-Yi

    2014-06-01

    The present of atlanto-axial pedicle screw fixation through posterior approach provide a new remedy for treating instability of pillow and cervical. A lot of researches have reported feasibility of atlanto-axial pedicle screw fixation, the results showed that it had advantages of easily exposure, less blood loss, shorter operative time, especially in treating as remedy fixation for atlanto-axial joint screw, atlas lateral mass screws and pedicle screw caused by injuries of tumor,inflammation and trauma. If not done properly, it can cause serious complications, such as iatrogenic fracture,injuries of vertebral artery and cervical spinal cord. Therefore,the safty and effectiveness of atlanto-axial pedicle screw fixation may be focus of research.

  19. Upgrade of axially loaded pile-soil modeling with the implementation of LRFD design procedure.

    Science.gov (United States)

    2012-02-01

    This report and the accompanying computer code (Software, WBUZPILE) describe the : characterization and analysis of piles under axial loads. A combination of different formulas : obtained from ALDOT long time experience along with fundamental equatio...

  20. Effect of Control Blade History, and Axial Coolant Density and Burnup Profiles on BWR Burnup Credit

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, William BJ J [ORNL

    2016-01-01

    A technical basis for peak reactivity boiling water reactor (BWR) burnup credit (BUC) methods was recently generated, and the technical basis for extended BWR BUC is now being developed. In this paper, a number of effects related to extended BWR BUC are analyzed, including three major operational effects in BWRs: the coolant density axial distribution, the use of control blades during operation, and the axial burnup profile. Specifically, uniform axial moderator density profiles are analyzed and compared to previous results and an additional temporal fidelity study combing moderator density profiles for three different fuel assemblies is presented. Realistic control blade histories and cask criticality results are compared to previously generated constructed control blade histories. Finally, a preliminary study of the axial burnup profile is provided.

  1. 'GRC1.5': Uptower Gearbox Testing to Investigate Bearing Axial Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan; Vaes, David; McNiff, Brian

    2016-02-16

    This presentation focuses on the investigation of bearing axial cracking using the GRC1.5 uptower gearbox. Topics covered include the testing options considered, the project goal, and current and near-term activities.

  2. Simulation of complex magnesium alloy texture using the axial component fit method with central normal distributions

    Science.gov (United States)

    Ivanova, T. M.; Serebryany, V. N.

    2017-12-01

    The component fit method in quantitative texture analysis assumes that the texture of the polycrystalline sample can be represented by a superposition of weighted standard distributions those are characterized by position in the orientation space, shape and sharpness of the scattering. The components of the peak and axial shapes are usually used. It is known that an axial texture develops in materials subjected to direct pressing. In this paper we considered the possibility of modelling a texture of a magnesium sample subjected to equal-channel angular pressing with axial components only. The results obtained make it possible to conclude that ECAP is also a process leading to the appearance of an axial texture in magnesium alloys.

  3. Synthesis of axially chiral benzamides utilizing tricarbonyl(arene)chromium complexes.

    Science.gov (United States)

    Koide, H; Uemura, M

    2000-06-01

    Axially chiral N,N-diethyl 2,6-disubstituted benzamides were stereo-selectively prepared utilizing planar chiral (arene)chromium complexes as an enantiomerically active form by following two methods. Ortho-lithiation of the enantiomerically pure planar chiral tricarbonyl(N,N-diethyl 2-methylbenzamide)chromium complex followed by electrophilic quenching gave axially chiral 2-methyl-6-substituted N,N-diethyl benzamide chromium complexes. Photo-oxidative demetalation produced the chromium-free axially chiral benzamides as optically active compounds. An alternative method for the preparation of axial chiral benzamides is an enantioselective lithiation at the benzylic methyl of meso tricarbonyl(N,N-diethyl 2,6-dimethylbenzamide)chromium with appropriate chiral lithium amide base followed by quenching with alkyl halides. Copyright 2000 Wiley-Liss, Inc.

  4. Posterior atlanto-occipital and atlanto-axial area and its surgical interest

    Directory of Open Access Journals (Sweden)

    Newton José Godoy Pimenta

    2014-10-01

    Full Text Available Classic anatomical studies describe two membranes – atlanto-occipital and atlanto-axial in the posterior aspect of the craniocervical region. During many surgical procedures in this area, however, we have not found such membranes. Objective To clarify the anatomical aspects and structures taking part of the posterior atlanto-occipital and atlanto-axial area. Method Analysis of histological cuts of three human fetuses and anatomical studies of 8 adult human cadavers. Results In both atlanto-occipital and atlanto-axial areas, we have observed attachment between suboccipital deep muscles and the spinal cervical dura. However, anatomical description of such attachments could not be found in textbooks of anatomy. Conclusion Our study shows the absence of the classical atlanto-occipital and atlanto-axial membranes; the occipito-C1 and C1-C2 posterior intervals are an open area, allowing aponeurotic attachment among cervical dura mater and posterior cervical muscles.

  5. Nonlinear Optical Macroscopic Assessment of 3-D Corneal Collagen Organization and Axial Biomechanics

    OpenAIRE

    Winkler, Moritz; Chai, Dongyul; Kriling, Shelsea; NIEN, CHYONG JY; Brown, Donald J.; Jester, Bryan; Juhasz, Tibor; Jester, James V.

    2011-01-01

    Collagen fibers in the anterior cornea are highly intertwined, unlike those in the posterior cornea. This axial gradient corresponds to a decrease in elastic modulus, suggesting that specific fiber organization controls corneal biomechanics and shape.

  6. Transverse Vibration of Axially Moving Functionally Graded Materials Based on Timoshenko Beam Theory

    Directory of Open Access Journals (Sweden)

    Suihan Sui

    2015-01-01

    Full Text Available The transverse free vibration of an axially moving beam made of functionally graded materials (FGM is investigated using a Timoshenko beam theory. Natural frequencies, vibration modes, and critical speeds of such axially moving systems are determined and discussed in detail. The material properties are assumed to vary continuously through the thickness of the beam according to a power law distribution. Hamilton’s principle is employed to derive the governing equation and a complex mode approach is utilized to obtain the transverse dynamical behaviors including the vibration modes and natural frequencies. Effects of the axially moving speed and the power-law exponent on the dynamic responses are examined. Some numerical examples are presented to reveal the differences of natural frequencies for Timoshenko beam model and Euler beam model. Moreover, the critical speed is determined numerically to indicate its variation with respect to the power-law exponent, axial initial stress, and length to thickness ratio.

  7. Residual Axial Capacity Comparison of CFFT and RC Bridge Columns after Fire

    Directory of Open Access Journals (Sweden)

    Alicia Echevarria

    2015-05-01

    Full Text Available The fire performance of protected concrete-filled fiber reinforced polymer (FRP tube (CFFT and conventional reinforced concrete (RC bridge columns is studied through two phases of experimental research comprised of fire exposure and residual axial capacity tests. Two one-fifth scale CFFT columns and two one-fifth scale conventional RC columns having similar axial and flexural capacities were subjected to two durations of extreme temperature exposure. The CFFT columns were protected by the Tyfo® CFP fire protection system during the experiments. Subsequently, the post-fire robustness of the columns was quantified by measuring the residual axial capacity characteristics of each column. The protected CFFT columns exhibited superior axial strength and stiffness retention compared to the RC columns after fire exposure.

  8. Axial seamount: An active ridge axis volcano on the Central Juan De Fuca Ridge

    Science.gov (United States)

    Johnson, H. Paul; Embley, Robert W.

    1990-08-01

    Axial Seamount (some of the manuscripts in this special section refer to the edifice with the more precise name of "Axial Volcano"), a large ridge axis volcano, is located on the central segment of the Juan de Fuca Ridge approximately 250 nautical miles west of the Washington/Oregon/British Columbia coast. Currently both volcanically and hydrothermally active, Axial lies directly at the intersection of the Cobb-Eickelberg Seamount Chain and the Juan de Fuca Ridge (Figure 1). The volcanic activity associated with the seamount formation strongly interacts with, and is affected by, the normal seafloor spreading processes at the intersection. Because of this unique geologic setting, its proximity to west coast ports and oceanographie institutions, and its shallow depth, Axial has become the focus of a large number of scientific investigations over the past decade.

  9. Dynamic axial stabilization of counterpropagating beam-traps with feedback control

    DEFF Research Database (Denmark)

    Tauro, Sandeep; Bañas, Andrew Rafael; Palima, Darwin

    2010-01-01

    . Here we propose a dynamic method for controlling axial forces to overcome this constraint. The technique uses computervision object tracking of the axial position, in conjunction with softwarebased feedback, for dynamically stabilizing the axial forces. We present proof-of-concept experiments showing...... real-time rapid repositioning coupled with a strongly enhanced axial trapping for a plurality of particles of varying sizes. We also demonstrate the technique’s adaptability for real-time reconfigurable feedback-trapping of a dynamically growing structure that mimics a continuously dividing cell colony....... Advanced implementation of this feedback-driven approach can help make CP-trapping resistant to a host of perturbations such as laser fluctuations, mechanical vibrations and other distortions emphasizing its experimental versatility....

  10. Finite-Bandwidth Resonances of High-Order Axial Modes (HOAM) in a Gyrotron Cavity

    OpenAIRE

    Sabchevski, Svilen; IDEHARA, Toshitaka

    2014-01-01

    Finite-bandwidth resonances of high-order axial modes (HOAM) in an open gyrotron cavity are studied numerically using the GYROSIM problem-oriented software package for modelling, simulation and computer-aided design (CAD) of gyrotron tubes.

  11. Control of the axial offset in a nuclear reactor at power maneuvering

    Directory of Open Access Journals (Sweden)

    Maksim V. Maksimov

    2014-12-01

    Full Text Available High reliability and security of power unit are basic requirements when the power unit maneuvering mode operation. The reactor stability under disturbances both at steady load and maneuvering load embodies the guarantees of power unit safe and reliable operation. A quantitative measure of the reactor stability is assessed by the axial offset representing the technological characteristics of energy release uniformity, therefore the axial offset minimum deviation is WWER-1000 operation efficiency measure. The power unit capacity automated control systems’ influence on axial offset under maneuvering mode is investigated. Considered is the power unit compromise-combined control program, which maintains a constant axial offset value when power unit switching from one power level to another.

  12. Fabrication of Tri-axially Oriented RE-Ba-Cu-O Ceramics by Magnetic Alignment

    Science.gov (United States)

    Yamaki, M.; Furuta, M.; Doi, T.; Shimoyama, J.; Horii, S.

    Magnetic alignment is a new crystal alignment process which enables tri-axial orientation without epitaxial growth at room temperature. In order to investigate the effectiveness of this magnetic tri-axial alignment process, we attempted to fabricate tri-axially oriented ErBa2Cu4O8 (Er124) ceramics by a slip-casting technique under two different modulated rotation magnetic fields (MRFs); uni-directional rotation type and oscillation type. For improvement of the degrees of tri-axial orientation in the Er124 green compacts slip-casted under MRFs, appropriate choice of sample-rotation method, magnetic field condition, control of mean diameter of source powders, and viscosity of slurry was found to be important in the case of MRFs induced by the sample-rotation. At the current stage, the degree of inplane orientation with ∼10̊ in Er124 was achieved.

  13. Atherosclerotic disease in axial spondyloarthritis: increased frequency of carotid plaques.

    Science.gov (United States)

    Rueda-Gotor, Javier; Corrales, Alfonso; Blanco, Ricardo; Fuentevilla, Patricia; Portilla, Virginia; Expósito, Rosa; Mata, Cristina; Pina, Trinitario; González-Juanatey, Carlos; Llorca, Javier; González-Gay, Miguel A

    2015-01-01

    To establish whether subclinical atherosclerosis is increased in patients with axial spondyloarthritis (ax-SpA). A set of 149 consecutive patients with no history of cardiovascular disease that fulfilled the Assessment of SpondyloArthritis International Society classification criteria for ax-SpA was studied by carotid ultrasonography. Carotid intima-media thickness (cIMT) and plaques were assessed. A series of 181 community-based controls with no cardiovascular disease were studied for comparison. To establish whether ax-SpA might have a direct effect on the risk of carotid plaques or an indirect effect via its putative influence on hypertension, dyslipidaemia or obesity, we obtained adjusted odds ratios (OR) for each clinical factor by the development of adjusted models. cIMT was increased in patients (0.621±0.123 mm) when compared to controls (0.607±0.117 mm) but the difference was not significant (p=0.30). Nevertheless, carotid plaques were more commonly observed in patients with ax-SpA than in controls (41.6% vs. 26.4%; p=0.003). Patients with plaques had longer duration of the disease than those without plaques (20.5±11.2 years vs. 12.0±8.6 years; p<0.001). Plaques were more frequent in patients with hip involvement (crude odds ratio 3.15, 95% confidence interval [CI] 1.02-9.75; p=0.05), syndesmophytes (crude OR 4.94, 95% CI 2.14-11.4; p<0.001), in patients with higher functional limitation and mobility index measured by BASFI (crude OR 1.16, 95% CI 1.02-1.33; p=0.03) and BASMI (crude OR 1.45, 95% CI 1.19-1.77; p<0.001), and in those with psoriasis (crude OR 3.94, 95% CI 1.31-11.84; p=0.02. However, except for psoriasis that continued being a strong risk factor for plaques after adjustment, the relationship between other clinical features of ax-SpA and carotid plaques disappeared in the adjusted models. Our results confirm the presence of subclinical atherosclerosis in patients with ax-SpA.

  14. Axial penile rigidity influences patient and partner satisfaction after penile prosthesis implantation

    Directory of Open Access Journals (Sweden)

    Abdulla Al Ansari

    2013-09-01

    Full Text Available Introduction: Penile prosthesis implantation is one of the treatment choices that is kept for patients who were not satisfied with other treatments. Although penile prosthesis satisfaction rates are higher, there are some dissatisfied patients. The patients’ reasons are mostly shortness and softness of implanted prosthesis. It was previously demonstrated that penile axial rigidity of more than 500 grams is enough for successful vaginal intromission. To our knowledge, there is no study comparing axial rigidity of penile prosthesis and satisfaction. Objectives: The aim of this study was to examine whether axial rigidity of penile prosthesis had impact on patient and partner satisfaction. Materials and Methods: We enrolled one hundred patients who were implanted penile prosthesis before to evaluate their penile axial rigidity. We used Rigidometry (by using the digital inflection rigidometer to assess the minimal axial pressure to bend the implanted penis. Results: We demonstrated that mean axial pressure to bend the implanted penis was 984.8 ± 268.7 grams. Overall satisfaction score with the penile prosthesis implant was 4.55 and 4.49 (out of 5 in patients and partners, respectively. In total, seven men were unsatisfied with their implant and reported a mean satisfaction score of 0.6 ± 0.48 (out of 5. All prostheses types showed good and more than 500 grams axial rigidity. The patients with Ambicor type, which were buckled at about 710.5 grams, showed worse satisfaction rates in comparison to other prostheses in two patients. Digital inflection rigidometer results of other penile prosthesis types in unsatisfied patient were 842.0, 872.0, 887.0 and 920 g. in CX700, Titan, Genesis and Titan OTR, respectively. Conclusion: We demonstrated that dissatisfaction rate was highest in Ambicor prosthesis implanted patients. Additionally, patients with 3-piece penile prosthesis were more satisfied than 2-piece or malleable ones, interestingly, although

  15. Experiments and analysis for an axially heterogeneous LMR assembly at ZPPR

    Energy Technology Data Exchange (ETDEWEB)

    Collins, P.J.; Brumbach, S. B.

    1988-01-01

    Experiments in ZPPR-17 provided physics data for a full-scale (700 MWe) axially heterogeneous LMR. Measurements and analysis are reported for control rod worths, reaction rate distributions, gamma dose distribution, sodium void worths and criticality. Agreement between measurement and calculation are generally satisfactory, but the axial heterogeneity did introduce analytical complications. Some calculational methods gave less good agreement with measurements than in previous homogeneous or radially heterogeneous assemblies. 10 refs., 7 figs., 6 tabs.

  16. ODONTOID PROCESS HYPOPLASIA AND BIPARTITE ATLAS ASSOCIATED WITH ATLANTO-AXIAL INSTABILITY

    OpenAIRE

    Marques, Luis Miguel Sousa; Romero, Clara; Cabral, José Gabriel Monteiro de Barros

    2016-01-01

    ABSTRACT Surgical treatment of craniocervical junction pathology has evolved considerably in recent years with the implementation of short fixation techniques rather than long occipito-cervical fixation (sub-axial). It is often difficult and sometimes misleading to determine the particular bone and vascular features (high riding vertebral artery, for instance) using only the conventional images in three orthogonal planes (axial, sagittal and coronal). The authors describe a rare clinical case...

  17. The met axial ligand determines the redox potential in Cu-A sites

    DEFF Research Database (Denmark)

    Ledesma, G.N.; Murgida, D.H.; Ly, H.K.

    2007-01-01

    The replacement of the axial methionine ligand in a native Cu-A protein rendered a series of stable mutants with spectroscopic features of a mixed valence center. The mutations resulted in minor perturbations of the electronic structure of this site but led to significant changes in the redox...... potential. This suggests that the axial ligand plays a role in tuning the redox potential Of Cu-A, resembling the behavior observed in blue copper sites....

  18. The accuracy of axial length measurements in cases of macula-off retinal detachment.

    Science.gov (United States)

    Abou-Shousha, Mohsen; Helaly, Hany Ahmed; Osman, Ihab Mohamed

    2016-04-01

    To assess the accuracy of axial length measurements in cases of macula-off retinal detachment using different methods (optical biometry, A-scan ultrasound, and combined applanation vector-A/B-scan biometry). This prospective clinical study included 100 eyes of 100 patients who underwent vitrectomy alone or phacovitrectomy for macula-off retinal detachment. All patients included signed an informed consent. Preoperative examination of the patients included recording the axial length measurements using optical biometry, A-scan ultrasound, and combined applanation vector-A/B-scan biometry. The mean postoperative IOLMaster axial length after macular reattachment was 26.11 ± 2.91 mm. The mean preoperative IOLMaster axial length with macula-off was 25.32 ± 2.72 mm. The mean preoperative A-scan axial length with macula-off was 25.29 ± 2.80 mm. The mean preoperative vector-A/B-scan axial length with macula-off was 26.03 ± 2.90 mm. The preoperative vector-A/B-scan mean absolute error was 0.59 ± 0.48 D (range, 0.10-2.25 D). Regular methods (optical biometry and A-scan biometry) of measuring the axial length in cases with a detached macula proved to be variable and less accurate. The vector-A/B-scan offered good measurements of the actual axial length in the patients. This was reflected on more accurate postoperative refractive outcome. Copyright © 2016 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  19. Differences in transmural pressure and axial loading ex vivo affect arterial remodeling and material properties.

    Science.gov (United States)

    Lawrence, Amanda R; Gooch, Keith J

    2009-10-01

    Arterial axial strains, present in the in vivo environment, often become reduced due to either bypass grafting or the normal aging process. Since the prevalence of hypertension increases with aging, arteries are often exposed to both decreased axial stretch and increased transmural pressure. The combined effects of these mechanical stimuli on the mechanical properties of vessels have not previously been determined. Porcine carotid arteries were cultured for 9 days at normal and reduced axial stretch ratios in the presence of normotensive and hypertensive transmural pressures using ex vivo perfusion techniques. Measurements of the amount of axial stress were obtained through longitudinal tension tests while inflation-deflation test results were used to determine circumferential stresses and incremental moduli. Macroscopic changes in artery geometry and zero-stress state opening angles were measured. Arteries cultured ex vivo remodeled in response to the mechanical environment, resulting in changes in arterial dimensions of up to approximately 25% and changes in zero-stress opening angles of up to approximately 55 degrees . While pressure primarily affected circumferential remodeling and axial stretch primarily affected axial remodeling, there were clear examples of interactions between these mechanical stimuli. Culture with hypertensive pressure, especially when coupled with reduced axial loading, resulted in a rightward shift in the pressure-diameter relationship relative to arteries cultured with normotensive pressure. The observed differences in the pressure-diameter curves for cultured arteries were due to changes in artery geometry and, in some cases, changes in the arteries' intrinsic mechanical properties. Relative to freshly isolated arteries, arteries cultured under mechanical conditions similar to in vivo conditions were stiffer, suggesting that aspects of the ex vivo culture other than the mechanical environment also influenced changes in the arteries

  20. Deflection and Supporting Force Analysis of a Slender Beam under Combined Transverse and Tensile Axial Loads

    Science.gov (United States)

    2016-05-01

    UNCLASSIFIED UNCLASSIFIED Deflection and Supporting Force Analysis of a Slender Beam under Combined Transverse and Tensile Axial Loads Witold...Bernoulli beam theory, and a closed-form expression for the beam deflection as a function of the axial tension force is provided. The analytical solution...was checked by performing a separate nonlinear finite element analysis using beam elements. The value of the peak deflection and its position along

  1. Axial Magneto-Inductive Effect in Soft Magnetic Microfibers, Test Methodology, and Experiments

    Science.gov (United States)

    2016-03-24

    pinning was Vt > 0.10 V. For voltages > the minimum, the axial magnetic field is large enough to overcome the molecular resistance between domains and...NUWC-NPT Technical Report 12,186 24 March 2016 Axial Magneto-Inductive Effect in Soft Magnetic Microfibers, Test Methodology, and...does not display a currently valid OPM control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 24-03-2016

  2. Axially symmetric static scalar solitons and black holes with scalar hair

    Energy Technology Data Exchange (ETDEWEB)

    Kleihaus, Burkhard, E-mail: kleihaus@theorie.physik.uni-oldenburg.de; Kunz, Jutta; Radu, Eugen; Subagyo, Bintoro

    2013-10-01

    We construct static, asymptotically flat black hole solutions with scalar hair. They evade the no-hair theorems by having a scalar potential which is not strictly positive. By including an azimuthal winding number in the scalar field ansatz, we find hairy black hole solutions which are static but axially symmetric only. These solutions possess a globally regular limit, describing scalar solitons. A branch of axially symmetric black holes is found to possess a positive specific heat.

  3. Design and Analysis of an Axially Laminated Reluctance Motor for Variable-Speed Applications

    OpenAIRE

    BESER, E. K.; CAMUR, S.; ARIFOGLU, B.; BESER, E.

    2013-01-01

    In this paper, an axially laminated reluctance motor is presented. First, a set of a finite element analysis (FEA) on three different axially laminated rotor geometries was carried out and torque profiles of the rotors were predicted. The effect of the stator slot skewing on the torque profiles were also examined in the analysis. After deciding the rotor geometry, the mathematical model of the proposed motor was formed in terms of a,b,c variables and simulations were performed. Motor prot...

  4. Axial penile rigidity influences patient and partner satisfaction after penile prosthesis implantation.

    Science.gov (United States)

    Al Ansari, Abdulla; Talib, Raidh A; Canguven, Onder; Shamsodini, Ahmad

    2013-09-26

    Penile prosthesis implantation is one of the treatment choices that is kept for patients who were not satisfied with other treatments. Although penile prosthesis satisfaction rates are higher, there are some dissatisfied patients. The patients’ reasons are mostly shortness and softness of implanted prosthesis. It was previously demonstrated that penile axial rigidity of more than 500 grams is enough for successful vaginal intromission. To our knowledge, there is no study comparing axial rigidity of penile prosthesis and satisfaction. The aim of this study was to examine whether axial rigidity of penile prosthesis had impact on patient and partner satisfaction. We enrolled one hundred patients who were implanted penile prosthesis before to evaluate their penile axial rigidity. We used Rigidometry (by using the digital inflection rigidometer) to assess the minimal axial pressure to bend the implanted penis. We demonstrated that mean axial pressure to bend the implanted penis was 984.8 ± 268.7 grams. Overall satisfaction score with the penile prosthesis implant was 4.55 and 4.49 (out of 5) in patients and partners, respectively. In total, seven men were unsatisfied with their implant and reported a mean satisfaction score of 0.6 ± 0.48 (out of 5). All prostheses types showed good and more than 500 grams axial rigidity. The patients with Ambicor type, which were buckled at about 710.5 grams, showed worse satisfaction rates in comparison to other prostheses in two patients. Digital inflection rigidometer results of other penile prosthesis types in unsatisfied patient were 842.0, 872.0, 887.0 and 920 g. in CX700, Titan, Genesis and Titan OTR, respectively. We demonstrated that dissatisfaction rate was highest in Ambicor prosthesis implanted patients. Additionally, patients with 3-piece penile prosthesis were more satisfied than 2-piece or malleable ones, interestingly, although some cases had lower axial rigidity results.

  5. Quasi-Static Compression and Low-Velocity Impact Behavior of Tri-Axial Bio-Composite Structural Panels Using a Spherical Head

    Science.gov (United States)

    Li, Jinghao; Hunt, John F; Gong, Shaoqin; Cai, Zhiyong

    2017-01-01

    This paper presents experimental results of both quasi-static compression and low-velocity impact behavior for tri-axial bio-composite structural panels using a spherical load head. Panels were made having different core and face configurations. The results showed that panels made having either carbon fiber fabric composite faces or a foam-filled core had significantly improved impact and compressive performance over panels without either. Different localized impact responses were observed based on the location of the compression or impact relative to the tri-axial structural core; the core with a smaller structural element had better impact performance. Furthermore, during the early contact phase for both quasi-static compression and low-velocity impact tests, the panels with the same configuration had similar load-displacement responses. The experimental results show basic compression data could be used for the future design and optimization of tri-axial bio-composite structural panels for potential impact applications. PMID:28772542

  6. Quasi-Static Compression and Low-Velocity Impact Behavior of Tri-Axial Bio-Composite Structural Panels Using a Spherical Head

    Directory of Open Access Journals (Sweden)

    Jinghao Li

    2017-02-01

    Full Text Available This paper presents experimental results of both quasi-static compression and low-velocity impact behavior for tri-axial bio-composite structural panels using a spherical load head. Panels were made having different core and face configurations. The results showed that panels made having either carbon fiber fabric composite faces or a foam-filled core had significantly improved impact and compressive performance over panels without either. Different localized impact responses were observed based on the location of the compression or impact relative to the tri-axial structural core; the core with a smaller structural element had better impact performance. Furthermore, during the early contact phase for both quasi-static compression and low-velocity impact tests, the panels with the same configuration had similar load-displacement responses. The experimental results show basic compression data could be used for the future design and optimization of tri-axial bio-composite structural panels for potential impact applications.

  7. Aerothermal optimization of partially shrouded axial turbines[Dissertation 17138

    Energy Technology Data Exchange (ETDEWEB)

    Porreca, L.

    2007-07-01

    This work presents the results of an aerodynamic and thermal study of three different shrouded axial turbine configurations (turbomachinery). The blade geometry of the turbine stages and the tip clearances of the test cases under investigation are identical although the shroud design is different. The first test case (RRD) is representative of a full shroud geometry while the second (CPS) and third (EPS) test cases adopt different partial shroud arrangements. In the EPS case, a shroud platform is added to cover the blade throat. Partial shrouds are sometimes used in industrial application in order to benefit from the aerodynamic advantage of shrouded configuration as well as reducing thermal load and mechanical stress on the blade root. However, the optimal compromise between mechanical issues and aerodynamic performances is still an open issue due to the resulting highly 3-dimensional unsteady flow field, difficulty of achieve an optimal cooling and severe heat load on the shroud sealing fins. An experimental investigation is carried out in order to quantify the effect of the shroud geometry on the aerodynamic performances and to study the resultant flow field in all test cases. The analysis has been conducted in an experimental low-speed axial turbine facility at the Turbomachinery Laboratory at ETH Zurich. Steady and fast response aerodynamic probe technology (FRAP) has been used to characterize the flow field. Moreover, a stereoscopic PIV technique has been design and applied in this experimental facility for the first time. The flow field analysis shows that the effect of the shroud geometry is significant from 60% blade height span to the tip. Tip leakage vortex in the first rotor is originated in the partial shroud test cases while the full shroud case present only a weak indigenous tip passage vortex. Secondary flows development in the following second stator resulted to be greatly affected by the leakage/main flow interaction of the first rotor. The

  8. Performance analysis of axial flow pump on gap changing between impeller and guide vane

    Science.gov (United States)

    Wang, W. J.; Liang, Q. H.; Wang, Y.; Yang, Y.; Yin, G.; Shi, X. X.

    2013-12-01

    In order to study the influence on gap changing of the static and dynamic components in axial flow pump, the axial flow pump model (TJ04-ZL-06) that used in the eastern of south-to-north water diversion project was selected. Steady turbulence field with different gaps was simulated by standard κ-ε turbulence model and double-time stepping methods. Information on the pressure distribution and velocity distribution of impeller surfaces were obtained. Then, calculated results were compared with the test results and analyzed. The results show that the performance of pump is not sensitive with the axial gap width under design conditions and the large flow rate condition. With increasing gap width, it will be improved in low flow rate condition. The attack angle of impeller inlet in small flow rate condition become small and the flow separation phenomenon can be observed in this condition. The axial velocity distribution of impeller outlet is nonlinear and to increase the axial gap is to improve the flow pattern near the hub effectively. The trend of calculating results is identical with test. It will play a guiding role to the axial pump operation and design in south-to-north water diversion project.

  9. Generalized dynamic model and control of ambiguous mono axial vehicle robot

    Directory of Open Access Journals (Sweden)

    Frantisek Duchon

    2016-09-01

    Full Text Available This article deals with the novel concept of ambiguous mono axial vehicle robot. Such robot is a combination of Segway and dicycle, which utilizes the advantages of each chassis. The advantage of dicycle is lower energy consumption during the movement and the higher safety of carried payload. The movable platform inside the ambiguous mono axial vehicle allows using the various sensors or devices. This will change the ambiguous mono axial vehicle to the Segway type robot. Both these modes are necessary to control in the stable mode to ensure the safety of the ambiguous mono axial vehicle’s movement. The main contents of the article contain description of generalized dynamic model of ambiguous mono axial vehicle and related control of ambiguous mono axial vehicle. The proposal is unique in that the same controller is used for both modes. Several simulations verify proposed control schemes and identified parameters. Moreover, the dicycle type of platform has never been used in robotics and that is another novelty.

  10. Axial mercury vapour pressure distributions in DC operated low pressure mercury argon discharges

    Science.gov (United States)

    Gielen, John; de Groot, Simon; van Dijk, Jan; van der Mullen, Joost

    2000-10-01

    In a steady state DC operated (cylindrical) low pressure mercury argon discharge, an electric field exists in axial direction which results in a non-uniform axial mercury vapour pressure distribution; this phenomenon is termed cataphoresis. In a discharge tube covered with a fluorescent powder this gives in a non-uniform axial light distribution. Towards lighting applications this is a potential disadvantage, which is not present in AC operated fluorescent lamps. The dependence of the axial mercury vapour pressure distribution under DC operation on discharge tube and discharge parameters has been investigated. A model has been developed to predict the axial mercury vapour pressure distribution, in which the balance equations for particle and momentum conservation are solved in combination with a plasma physical model, and experiments have been performed to validate the model. In the present contribution the model and experimental results will be discussed and it will be demonstrated that the applied theoretical approach provides a better description of the axial mercury vapour pressure distribution compared to previous models known from literature.

  11. A new bi-axial cantilever beam design for biomechanics force measurements.

    Science.gov (United States)

    Lin, Huai-Ti; Trimmer, Barry A

    2012-08-31

    The demand for measuring forces exerted by animals during locomotion has increased dramatically as biomechanists strive to understand and implement biomechanical control strategies. In particular, multi-axial force transducers are often required to capture animal limb coordination patterns. Most existing force transducers employ strain gages arranged in a Wheatstone bridge on a cantilever beam. Bi-axial measurements require duplicating this arrangement in the transverse direction. In this paper, we reveal a method to embed a Wheatstone bridge inside another to allow bi-axial measurements without additional strain gages or additional second beams. This hybrid configuration resolves two force components from a single bridge circuit and simplifies fabrication for the simultaneous assessment of normal and transverse loads. This design can be implemented with two-dimensional fabrication techniques and can even be used to modify a common full bridge cantilever force transducer. As a demonstration of the new design, we built a simple beam which achieved bi-axial sensing capability that outperformed a conventional half-bridge-per-axis bi-axial strain gage design. We have used this design to measure the ground reaction forces of a crawling caterpillar and a caterpillar-mimicking soft robot. The simplicity and increased sensitivity of this method could facilitate bi-axial force measurements for experimental biologists. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Measurement of hemodynamic changes with the axial flow blood pump installed in descending aorta.

    Science.gov (United States)

    Okamoto, Eiji; Yano, Tetsuya; Miura, Hidekazu; Shiraishi, Yasuyuki; Yambe, Tomoyuki; Mitamura, Yoshinori

    2017-12-01

    We have developed various axial flow blood pumps to realize the concept of the Valvo pump, and we have studied hemodynamic changes under cardiac assistance using an axial flow blood pump in series with the natural heart. In this study, we measured hemodynamic changes of not only systemic circulation but also cerebral circulation and coronary circulation under cardiac support using our latest axial flow blood pump placed in the descending aorta in an acute animal experiment. The axial flow blood pump was installed at the thoracic descending aorta through a left thoracotomy of a goat (43.8 kg, female). When the pump was on, the aortic pressure and aortic flow downstream of the pump increased with preservation of pulsatilities. The pressure drop upstream of the pump caused reduction of afterload pressure, and it may lead to reduction of left ventricular wall stress. However, cerebral blood flow and coronary blood flow were decreased when the pump was on. The axial flow blood pump enables more effective blood perfusion into systemic circulation, but it has the potential risk of blood perfusion disturbance into cerebral circulation and coronary circulation. The results indicate that the position before the coronary ostia might be suitable for implantation of the axial flow blood pump in series with the natural heart to avoid blood perfusion disturbances.

  13. Quantitative cw Overhauser effect dynamic nuclear polarization for the analysis of local water dynamics.

    Science.gov (United States)

    Franck, John M; Pavlova, Anna; Scott, John A; Han, Songi

    2013-10-01

    Liquid state Overhauser effect Dynamic Nuclear Polarization (ODNP) has experienced a recent resurgence of interest. The ODNP technique described here relies on the double resonance of electron spin resonance (ESR) at the most common, i.e. X-band (∼10GHz), frequency and ¹H nuclear magnetic resonance (NMR) at ∼15 MHz. It requires only a standard continuous wave (cw) ESR spectrometer with an NMR probe inserted or built into an X-band cavity. We focus on reviewing a new and powerful manifestation of ODNP as a high frequency NMR relaxometry tool that probes dipolar cross relaxation between the electron spins and the ¹H nuclear spins at X-band frequencies. This technique selectively measures the translational mobility of water within a volume extending 0.5-1.5 nm outward from a nitroxide radical spin probe that is attached to a targeted site of a macromolecule. It allows one to study the dynamics of water that hydrates or permeates the surface or interior of proteins, polymers, and lipid membrane vesicles. We begin by reviewing the recent advances that have helped develop ODNP into a tool for mapping the dynamic landscape of hydration water with sub-nanometer locality. In order to bind this work coherently together and to place it in the context of the extensive body of research in the field of NMR relaxometry, we then rephrase the analytical model and extend the description of the ODNP-derived NMR signal enhancements. This extended model highlights several aspects of ODNP data analysis, including the importance of considering all possible effects of microwave sample heating, the need to consider the error associated with various relaxation rates, and the unique ability of ODNP to probe the electron-¹H cross-relaxation process, which is uniquely sensitive to fast (tens of ps) dynamical processes. By implementing the relevant corrections in a stepwise fashion, this paper draws a consensus result from previous ODNP procedures and then shows how such data can be

  14. Dose profile measurement in computerized axial tomography equipment using thermoluminescent dosemeters; Medicion del perfil de dosis en equipos de tomografia axial computarizada usando dosimetros termoluminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Azorin V, J.C.; Falcony, C.; Azorin N, J. [Centro de Investigacion en Ciencia y Tecnologia Avanzada, IPN, 07000 Mexico D.F. (Mexico)

    2000-07-01

    In this work are presented the results about measuring the radiation dose profile in two equipment of computerized axial tomography (Tac). Thermoluminescent dosemeters (Dtl) of LiF, Mg, Cu, P + Ptfe in form of disks were used which were developed and made in Mexico. The results showed that Dtl are appropriated for these type of studies. (Author)

  15. Infrared thermography with non-uniform heat flux boundary conditions on the rotor endwall of an axial turbine

    Science.gov (United States)

    Lazzi Gazzini, S.; Schädler, R.; Kalfas, A. I.; Abhari, R. S.

    2017-02-01

    It is technically challenging to measure heat fluxes on the rotating components of gas turbines, yet accurate knowledge of local heat loads under engine-representative conditions is crucial for ensuring the reliability of the designs. In this work, quantitative image processing tools were developed to perform fast and accurate infrared thermography measurements on 3D-shaped film-heaters directly deposited on the turbine endwalls. The newly developed image processing method and instrumentation were used to measure the heat load on the rotor endwalls of an axial turbine. A step-transient heat flux calibration technique is applied to measure the heat flux generated locally by the film heater, thus eliminating the need for a rigorously iso-energetic boundary condition. On-board electronics installed on the rotor record the temperature readings of RTDs installed in the substrate below the heaters in order to evaluate the conductive losses in the solid. Full maps of heat transfer coefficient and adiabatic wall temperature are produced for two different operating conditions, demonstrating the sensitivity of the technique to local flow features and variations in heat transfer due to Reynolds number effect.

  16. In-shoe plantar tri-axial stress profiles during maximum-effort cutting maneuvers.

    Science.gov (United States)

    Cong, Yan; Lam, Wing Kai; Cheung, Jason Tak-Man; Zhang, Ming

    2014-12-18

    Soft tissue injuries, such as anterior cruciate ligament rupture, ankle sprain and foot skin problems, frequently occur during cutting maneuvers. These injuries are often regarded as associated with abnormal joint torque and interfacial friction caused by excessive external and in-shoe shear forces. This study simultaneously investigated the dynamic in-shoe localized plantar pressure and shear stress during lateral shuffling and 45° sidestep cutting maneuvers. Tri-axial force transducers were affixed at the first and second metatarsal heads, lateral forefoot, and heel regions in the midsole of a basketball shoe. Seventeen basketball players executed both cutting maneuvers with maximum efforts. Lateral shuffling cutting had a larger mediolateral braking force than 45° sidestep cutting. This large braking force was concentrated at the first metatarsal head, as indicated by its maximum medial shear stress (312.2 ± 157.0 kPa). During propulsion phase, peak shear stress occurred at the second metatarsal head (271.3 ± 124.3 kPa). Compared with lateral shuffling cutting, 45° sidestep cutting produced larger peak propulsion shear stress (463.0 ± 272.6 kPa) but smaller peak braking shear stress (184.8 ± 181.7 kPa), of which both were found at the first metatarsal head. During both cutting maneuvers, maximum medial and posterior shear stress occurred at the first metatarsal head, whereas maximum pressure occurred at the second metatarsal head. The first and second metatarsal heads sustained relatively high pressure and shear stress and were expected to be susceptible to plantar tissue discomfort or injury. Due to different stress distribution, distinct pressure and shear cushioning mechanisms in basketball footwear might be considered over different foot regions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Masses of scalar and axial-vector B mesons revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hai-Yang [Academia Sinica, Institute of Physics, Taipei (China); Yu, Fu-Sheng [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)

    2017-10-15

    The SU(3) quark model encounters a great challenge in describing even-parity mesons. Specifically, the q anti q quark model has difficulties in understanding the light scalar mesons below 1 GeV, scalar and axial-vector charmed mesons and 1{sup +} charmonium-like state X(3872). A common wisdom for the resolution of these difficulties lies on the coupled channel effects which will distort the quark model calculations. In this work, we focus on the near mass degeneracy of scalar charmed mesons, D{sub s0}{sup *} and D{sub 0}{sup *0}, and its implications. Within the framework of heavy meson chiral perturbation theory, we show that near degeneracy can be qualitatively understood as a consequence of self-energy effects due to strong coupled channels. Quantitatively, the closeness of D{sub s0}{sup *} and D{sub 0}{sup *0} masses can be implemented by adjusting two relevant strong couplings and the renormalization scale appearing in the loop diagram. Then this in turn implies the mass similarity of B{sub s0}{sup *} and B{sub 0}{sup *0} mesons. The P{sub 0}{sup *}P{sub 1}{sup '} interaction with the Goldstone boson is crucial for understanding the phenomenon of near degeneracy. Based on heavy quark symmetry in conjunction with corrections from QCD and 1/m{sub Q} effects, we obtain the masses of B{sup *}{sub (s)0} and B{sup '}{sub (s)1} mesons, for example, M{sub B{sub s{sub 0{sup *}}}} = (5715 ± 1) MeV + δΔ{sub S}, M{sub B}{sup {sub '{sub s{sub 1}}}} = (5763 ± 1) MeV + δΔ{sub S} with δΔ{sub S} being 1/m{sub Q} corrections. We find that the predicted mass difference of 48 MeV between B{sup '}{sub s1} and B{sub s0}{sup *} is larger than that of 20-30 MeV inferred from the relativistic quark models, whereas the difference of 15 MeV between the central values of M{sub B}{sup {sub '{sub s{sub 1}}}} and M{sub B}{sup {sub '{sub 1}}} is much smaller than the quark model expectation of 60-100 MeV. Experimentally, it is important to have a precise

  18. Probing Framework-Restricted Metal Axial Ligation and Spin State Patterns in a Post-Synthetically Reduced Iron-Porphyrin-Based Metal–Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Kucheryavy, Pavel; Lahanas, Nicole; Velasco, Ever; Sun, Cheng-Jun; Lockard, Jenny V.

    2016-04-07

    An iron porphyrin-based metal organic framework, PCN-222(Fe) is investigated upon post-synthetic reduction with piperidine. Fe K-edge X-ray absorption and Kβ mainline emission spectroscopy measurements reveal the local coor-dination geometry, oxidation and spin state changes experi-enced by the Fe sites upon reaction with this axially coordi-nating reducing agent. Analysis and fitting of these data con-firm the binding pattern predicted by a space filling model of the structurally constrained pore environments. These results are further support by UV-vis diffuse reflectance, IR and Raman spectroscopy data.

  19. DRY BEAN HARVEST WITH AXIAL THRASHER COMBINE COLHEITA DIRETA DE FEIJÃO COM COLHEDORA AUTOMOTRIZ AXIAL

    Directory of Open Access Journals (Sweden)

    Homero Aidar

    2009-10-01

    Full Text Available

    Dry bean mechanized harvest is a common practice in large and medium farms. However, many factors have made difficult the use of combines. Mechanized harvest requires special care because many pods are near the ground, causing significant grain losses. It was set up an experiment to evaluate the dry bean harvest by a combine equipped with flexible cutting platform and axial thrasher. The factors studied were: two dry bean cultivars (BRS Valente and Iapar 81, two harvest periods (morning and afternoon, and three operation speeds (3 km h-1, 5 km h-1, and 7 km h-1. Harvest plant height and grain loss were 93 mm and 135 kg ha-1, respectively. This grain loss was higher in the afternoon than in the morning. The combine speed operation affected plant cut height as well as grain loss. The grain damage was affected by combine operation speed and grain moisture. The combine performance, based on grain quality and capacity of work, was dependent on the speed operation, cultivar type, and grain moisture.

    KEY-WORDS: Grain loss; grain quality; speed operation; harvest period; dry bean cultivars.

  20. Localized shocks

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Daniel A. [Center for Theoretical Physics and Department of Physics,Massachusetts Institute of Technology, Cambridge, MA (United States); Stanford, Douglas [Stanford Institute for Theoretical Physics and Department of Physics,Stanford University, Stanford, CA (United States); School of Natural Sciences, Institute for Advanced Study,Princeton, NJ (United States); Susskind, Leonard [Stanford Institute for Theoretical Physics and Department of Physics,Stanford University, Stanford, CA (United States)

    2015-03-10

    We study products of precursors of spatially local operators, W{sub x{sub n}}(t{sub n})…W{sub x{sub 1}}(t{sub 1}), where W{sub x}(t)=e{sup −iHt}W{sub x}e{sup iHt}. Using chaotic spin-chain numerics and gauge/gravity duality, we show that a single precursor fills a spatial region that grows linearly in t. In a lattice system, products of such operators can be represented using tensor networks. In gauge/gravity duality, they are related to Einstein-Rosen bridges supported by localized shock waves. We find a geometrical correspondence between these two descriptions, generalizing earlier work in the spatially homogeneous case.

  1. Axial and radial velocities in the creeping flow in a pipe

    Directory of Open Access Journals (Sweden)

    Zuykov Andrey L'vovich

    2014-05-01

    Full Text Available The article is devoted to analytical study of transformation fields of axial and radial velocities in uneven steady creeping flow of a Newtonian fluid in the initial portion of the cylindrical channel. It is shown that the velocity field of the flow is two-dimensional and determined by the stream function. The article is a continuation of a series of papers, where normalized analytic functions of radial axial distributions in uneven steady creeping flow in a cylindrical tube with azimuthal vorticity and stream function were obtained. There is Poiseuille profile for the axial velocity in the uniform motion of a fluid at an infinite distance from the entrance of the pipe (at x = ∞, here taken equal to zero radial velocity. There is uniform distribution of the axial velocity in the cross section at the tube inlet at x = 0, at which the axial velocity is constant along the current radius. Due to the axial symmetry of the flow on the axis of the pipe (at r = 0, the radial velocities and the partial derivative of the axial velocity along the radius, corresponding to the condition of the soft function extremum, are equal to zero. The authors stated vanishing of the velocity of the fluid on the walls of the pipe (at r = R , where R - radius of the tube due to its viscous sticking and tightness of the walls. The condition of conservation of volume flow along the tube was also accepted. All the solutions are obtained in the form of the Fourier - Bessel. It is shown that the hydraulic losses at uniform creeping flow of a Newtonian fluid correspond to Poiseuille - Hagen formula.

  2. Axial length elongation in adults with long-standing unilateral traumatic cataract

    Directory of Open Access Journals (Sweden)

    Jonel Steffen

    2016-03-01

    Full Text Available Background: Unilateral eye elongation with resultant axial myopia has been reported to occur secondary to visual deprivation from birth or early childhood. Acquired axial length elongation secondary to visual deprivation in adults has rarely been reported.Aim: To report acquired axial myopia in adults with visual deprivation due to long-standing unilateral traumatic cataract.Methods: Eleven consecutive adult patients who presented for cataract surgery with unilateral, long-standing, mature, traumatic cataracts and an interocular axial length difference of more than 1 mm were studied. Patients with a post-operative best corrected visual acuity (BCVA of < 6/12 were excluded to rule out possible pre-existing anisometropic amblyopia.Results: Of the 11 patients with significant interocular axial length difference, 5 patients were excluded on the basis of possible pre-existing amblyopia. The remaining 6 patients had final BCVA of 6/12 or better. The median length of the cataractous eyes was 2.83 mm longer than the fellow eyes (range 1.12 mm – 3.52 mm. The intraocular lens power required for emmetropia was 6.8 dioptres (range 3.5 dioptres – 11.5 dioptres less in the cataractous eyes. A refractive outcome within 1 dioptre of the target refraction was achieved in all patients. The median delay between ocular trauma and cataract surgery was 20 years (range 8–24 years.Conclusion: Significant unilateral axial length elongation may occur in adults with longstanding traumatic cataracts and visual deprivation. A potential correlation may exist between delay to surgery and degree of axial length difference. This rare phenomenon must be considered when determining intraocular lens power to avoid post-operative refractive surprises.

  3. Effects of axial length and corneal curvature on corneal biomechanics in elderly population

    Directory of Open Access Journals (Sweden)

    Sha-Sha Song

    2018-02-01

    Full Text Available AIM:To explore the corneal biomechanical properties of the elderly with different axial length(ALand corneal curvature by corneal visualization Scheimpflug Technology(Corvis ST. METHODS: Cross-sectional study. A total of 161 patients(297 eyesundergoing phacoemulsification were collected in this study. They were divided into 22-24mm, 24-26mm, more than 26mm groups according to axial length(190 eyes, 54 eyes and 53 eyes, respectively. Those of whom axial length was 22-24mm and the corneal curvature was 42-44D were divided into male and female groups(44 eyes and 49 eyes, respectively. Those of whom axial length was 22-24mm were divided into 42-44D group, more than 44D group according to corneal curvature(88 eyes, 102 eyes, respectively. Corvis ST was used to measure the biomechanical parameters of the cornea. The differences in the parameters between different groups were analyzed using the independent-samples t test or one-way analysis of variance and correlation analyses were performed using Pearson correlation analysis. RESULTS: When comparing the corneal biomechanical parameters, no statistically significant differences were found between male and female groups(P>0.05. The first applanation length and second applanation length among different corneal curvatures were statistically significant(PPr=0.429, 0.278; Pr=-0.291, -0.415; PCONCLUSION: The corneal curvature and ocular axial length may be the factors affecting the corneal biomechanical characteristics. The longer axial length, the thinner corneal thickness, the more easily the corneal is deformed, and with the increase of the axial length, intraocular pressure also increases.

  4. Effect of axial length reduction after trabeculectomy on the development of hypotony maculopathy.

    Science.gov (United States)

    Matsumoto, Yoshiko; Fujihara, Masashi; Kanamori, Akiyasu; Yamada, Yuko; Nakamura, Makoto

    2014-05-01

    To measure changes in axial length before and after trabeculectomy with noncontact, partial coherence laser interferometry and identify patient factors that lead to the development of hypotony maculopathy and axial length shortening in 25 eyes with intraocular pressure (IOP) ≤ 6 mmHg at 4 weeks after mitomycin C-augmented trabeculectomy. A retrospective comparative case series. Hypotony maculopathy was identified with both ophthalmoscopy and spectral-domain optical coherence tomography. Axial length and IOP were serially measured pre- and postoperatively. Logistic regression analysis was performed to identify factors associated with the presence of hypotony maculopathy at 4 weeks after trabeculectomy and multiple regression analysis to identify factors associated with axial length changes. Ten eyes exhibited hypotony maculopathy, whereas the remaining 15 did not. Patients with hypotony maculopathy were significantly younger (47.7 ± 6.2 years) compared with those without it (63.3 ± 9.6 years, P = 0.0002, unpaired t test). The percent reduction of axial length after trabeculectomy was significantly larger in the former group (5.91 ± 2.76 %) compared with the latter group (1.51 ± 0.91 %) (P = 0.0001, Mann-Whitney U test). Multivariate analyses showed that only age was associated with the presence of hypotony maculopathy, with an odds ratio of 0.82 (P = 0.0075), when age, sex, type of glaucoma, lens status, percent changes in axial length and IOP before and after trabeculectomy, and central corneal thickness were included as independent variables (R (2) = 0.543, P = 0.003). Age-dependent axial length reduction is a risk factor for the development of hypotony maculopathy after trabeculectomy.

  5. Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator

    Science.gov (United States)

    Andersson, P.; Andersson-Sunden, E.; Sjöstrand, H.; Jacobsson-Svärd, S.

    2014-08-01

    In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm-1, solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful indication

  6. Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator.

    Science.gov (United States)

    Andersson, P; Andersson-Sunden, E; Sjöstrand, H; Jacobsson-Svärd, S

    2014-08-01

    In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm(-1), solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful

  7. Localized shocks

    OpenAIRE

    Stanford, Douglas; Susskind, Leonard; Roberts, Daniel Adam

    2014-01-01

    We study products of precursors of spatially local operators, W[subscript xn](tn)⋅⋅⋅W[subscript x1](t[subscript 1]), where W [subscript x] (t) = e [superscript − iHt] W [subscript x] e [superscript iHt]. Using chaotic spin-chain numerics and gauge/gravity duality, we show that a single precursor fills a spatial region that grows linearly in t. In a lattice system, products of such operators can be represented using tensor networks. In gauge/gravity duality, they are related to Einstein-Rosen ...

  8. Optimización de Estatores para Motores Superconductores de Flujo Axial Optimización de Estatores para Motores Superconductores de Flujo Axial

    Directory of Open Access Journals (Sweden)

    Oscar Gerardo Ibarra-Manzano

    2012-02-01

    Full Text Available The development of superconducting electrical machines has been designed primarily to design and build engines with the superconducting magnetic field in radial configuration, as traditional engines, so the design and construction of rotating electrical machines in axial flow configuration has become an alternative for the design and construction of such engines. In this paper we present preliminary calculations for the optimization of the stator of a superconducting motor in axial flow confi guration, based on the equations of general power of the rotary axial flow configuration. It performs the construction, optimization and evaluation of models of stators in geometries of 4, 6 and 8 poles with high-temperature superconducting tapes of Bismuth. The results show the feasibility of the design implemented, which is verified by a significant decrease in the current of superconducting motor operation.El desarrollo de máquinas eléctricas superconductoras ha estado encaminado principalmentea diseñar y construir motores superconductores con el campo magnético en configuración radial, como los motores tradicionales, por lo que el diseño y construcción demáquinas eléctricas rotativas en configuración de flujo axial ha venido a ser una alternativa para el diseño y construcción de este tipo de motores. En el presente trabajo se presentan los cálculos preliminares para la optimización del estator de un motor superconductor en configuración de flujo axial, basados en las ecuaciones generales de potencia de las máquinas eléctricas rotativas en configuración flujo axial ha venido a ser una alternativa para el diseño y construcción, optimización y evaluación de modelos de estatores en geometrías de 4, 6 y 8 polos, con cintas superconductoras de alta temperatura de Bismuto. Los resultados obtenidos muestran la viabilidaddel diseño implementado, lo cual se comprueba por medio de una disminución significativa de la corriente de operaci

  9. East Pacific Rise from Siqueiros to Orozco Fracture Zones: Along-strike continuity of axial neovolcanic zone and structure and evolution of overlapping spreading centers

    Science.gov (United States)

    MacDonald, Ken; Sempere, Jean-Christophe; Fox, P. J.

    1984-07-01

    features are associated with along-strike minima in the magmatic budget. We suggest that major phases of volcanic activity propagate episodically along the axis away from centers of magmatic inflation and that OSC's develop where magmatic pulses fail to meet due to misalignment of fracture systems, sinuous bends in the rise axis, or other heterogeneities. Transform faults fail to develop on fast spreading centers where the lateral offsets are small (<15 km) because the lithosphere is too thin and weak to maintain a classic rigid plate ridge/transform fault pattern. The OSC geometry is unstable and evolves rapidly, and the overlapping rises may propagate at rates faster than the local spreading rate. One of the two OSC's prevails, while the other is abandoned. While the locations of OSC's may not be fixed relative to the rise axis, they may tend to recur near the same place, creating scars in older lithosphere which resemble fracture zones, but whose fine-scale structure is quite different. There is excellent agreement between the observed structure of OSC's and laboratory studies of OSC's using wax models, photoelastic studies of overlapping cracks, and boundary element modeling of overlapping cracks. Seismic refraction and reflection near two OSC's suggests that large offset OSC's have separate magma chambers beneath the offset rise axes, while small offset OSC's may share a single axial magma chamber. Three-dimensional inversion of magnetic anomalies suggests that significant petrologic anomalies may occur near some OSC tips. Waxing and waning of overlapping magma chambers may give rise to the eruption of highly fractionated FeTi basalts and associated magnetic anomalies.

  10. Nuclear chiral axial currents and applications to few-nucleon systems

    Energy Technology Data Exchange (ETDEWEB)

    Baroni, Alessandro [Old Dominion Univ., Norfolk, VA (United States)

    2017-08-01

    This Thesis is divided into three main parts. The first part discusses basic aspects of chiral effective field theory and the formalism, based on time ordered perturbation theory, used to to derive the nuclear potentials and currents from the chiral Lagrangians. The second part deals with the actual derivation, up to one loop, of the two-nucleon potential and one- and two-nucleon weak axial charge and current. In both derivations ultraviolet divergences generated by loop corrections are isolated using dimensional regularization. The resulting axial current is finite and conserved in the chiral limit, while the axial charge requires renormalization. A complete set of contact terms for the axial charge up to the relevant order in the power counting is constructed. The third part of this Thesis discusses two applications: (i) the calculation of the Gamow-Teller matrix element of tritium, used to constrain the single low-energy constant entering the axial current; (ii) the calculation of neutrino-deuteron inclusive cross sections at low energies. These results have confirmed previous predictions obtained in phenomenological approaches. These latter studies have played an important role in the analysis and interpretation of experiments at the Sudbury Neutrino Observatory.

  11. Finite temperature study of the axial U(1) symmetry on the lattice with overlap fermion formulation

    Science.gov (United States)

    Cossu, Guido; Aoki, Sinya; Fukaya, Hidenori; Hashimoto, Shoji; Kaneko, Takashi; Matsufuru, Hideo; Noaki, Jun-Ichi

    2013-06-01

    We examine the axial U(1) symmetry near and above the finite-temperature phase transition in two-flavor QCD using lattice QCD simulations. Although the axial U(1) symmetry is always violated by quantization, i.e., the chiral anomaly, the correlation functions may manifest effective restoration of the symmetry in the high-temperature phase. We explicitly study this possibility by calculating the meson correlators as well as the Dirac operator spectral density near the critical point. Our numerical simulations are performed on a 163×8 lattice with two flavors of dynamical quarks represented by the overlap fermion formalism. Chiral symmetry and its violation due to the axial anomaly is manifestly realized with this formulation, which is a prerequisite for the study of the effective restoration of the axial U(1) symmetry. In order to avoid discontinuity in the gauge configuration space, which occurs for the exactly chiral lattice fermions, the simulation is confined in a fixed topological sector. It induces a finite-volume effect, which is well described by a formula based on the Fourier transform from the θ vacua. We confirm this formula at finite temperature by calculating the topological susceptibility in the quenched theory. Our two-flavor simulations show degeneracy of the meson correlators and a gap in the Dirac operator spectral density, which implies that the axial U(1) symmetry is effectively restored in the chirally symmetric phase.

  12. Theoretical analysis to investigate thermal performance of co-axial heat pipe solar collector

    Science.gov (United States)

    Azad, E.

    2011-12-01

    The thermal performance of co-axial heat pipe solar collector which consist of a collector 15 co-axial heat pipes surrounded by a transparent envelope and which heat a fluid flowing through the condenser tubes have been predicted using heat transfer analytical methods. The analysis considers conductive and convective losses and energy transferred to a fluid flowing through the collector condenser tubes. The thermal performances of co-axial heat pipe solar collector is developed and are used to determine the collector efficiency, which is defined as the ratio of heat taken from the water flowing in the condenser tube and the solar radiation striking the collector absorber. The theoretical water outlet temperature and efficiency are compared with experimental results and it shows good agreement between them. The main advantage of this collector is that inclination of collector does not have influence on performance of co-axial heat pipe solar collector therefore it can be positioned at any angle from horizontal to vertical. In high building where the roof area is not enough the co-axial heat pipe solar collectors can be installed on the roof as well as wall of the building. The other advantage is each heat pipe can be topologically disconnected from the manifold.

  13. Axial T2* mapping in intervertebral discs: a new technique for assessment of intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Sven; Quirbach, Sebastian; Krause, Fabian G.; Benneker, Lorin M. [Inselspital, Berne University Hospital, Department of Orthopaedic Surgery, Berne (Switzerland); Mamisch, Tallal C. [Inselspital, Berne University Hospital, Department of Radiology, Berne (Switzerland); Werlen, Stefan [Clinic Sonnenhof, Department of Radiology, Berne (Switzerland)

    2012-09-15

    To demonstrate the potential benefits of biochemical axial T2* mapping of intervertebral discs (IVDs) regarding the detection and grading of early stages of degenerative disc disease using 1.5-Tesla magnetic resonance imaging (MRI) in a clinical setting. Ninety-three patients suffering from lumbar spine problems were examined using standard MRI protocols including an axial T2* mapping protocol. All discs were classified morphologically and grouped as ''healthy'' or ''abnormal''. Differences between groups were analysed regarding to the specific T2* pattern at different regions of interest (ROIs). Healthy intervertebral discs revealed a distinct cross-sectional T2* value profile: T2* values were significantly lower in the annulus fibrosus compared with the nucleus pulposus (P = 0.01). In abnormal IVDs, T2* values were significantly lower, especially towards the centre of the disc representing the expected decreased water content of the nucleus (P = 0.01). In herniated discs, ROIs within the nucleus pulposus and ROIs covering the annulus fibrosus showed decreased T2* values. Axial T2* mapping is effective to detect early stages of degenerative disc disease. There is a potential benefit of axial T2* mapping as a diagnostic tool, allowing the quantitative assessment of intervertebral disc degeneration. circle Axial T2* mapping effective in detecting early degenerative disc disease. (orig.)

  14. CONTRIBUTION OF AXIAL MOTOR IMPAIRMENT TO PHYSICAL INACTIVITY IN PARKINSON'S DISEASE

    Science.gov (United States)

    Bryant, Mon S; Hou, Jyhgong Gabriel; Collins, Robert L; Protas, Elizabeth J

    2015-01-01

    Objective To investigate the relationships between motor symptoms of Parkinson’s disease (PD) and activity limitations in persons with PD. Design/Methods Cross-sectional study of persons with mild to moderate PD (N=90). Associations among axial motor features, limb motor signs, the Physical Activity Scale for Elders (PASE), the ability to perform Activities of Daily Living (ADL) and level of ADL dependency were studied. A composite score of axial motor features included the following UPDRS items: speech, rigidity of the neck, arising from chair, posture, gait and postural stability. A composite score of limb motor signs included the following UPDRS items: tremor at rest of all extremities, action tremor, rigidity of all extremities, finger taps, hand movement, rapid alternating hand movements and foot tapping. Results Axial motor features of PD were significantly correlated with physical inactivity (pphysical inactivity. After controlling for age, gender, disease duration and comorbidity, axial motor features contributed significantly to physical inactivity, decreased ADL and increase in ADL dependency, whereas the limb motor signs did not. Conclusions Axial motor impairment contributed to physical inactivity and decreased ability to perform ADLs in persons with PD. PMID:26368837

  15. Effect of Turbine Axial Nozzle-Wheel Clearance on Performance of Mark 25 Torpedo Power Plant

    Science.gov (United States)

    Hoyt, Jack W.; Kottas, Harry

    1948-01-01

    Investigations were made of the turbine from a Mark 25 torpedo to determine the performance of the unit with three different turbine nozzles at various axial nozzle-wheel clearances. Turbine efficiency with a reamed nondivergent nozzle that uses the axial clearance space for gas expansion was little affected by increasing the axial running clearance from 0.030 to 0.150 inch. Turbine efficiency with cast nozzles that expanded the gas inside the nozzle passage was found to be sensitive to increased axial nozzle-wheel clearance. A cast nozzle giving a turbine brake efficiency of 0.525 at an axial running clearance of 0.035 inch gave a brake efficiency of 0.475 when the clearance was increased to 0.095 inch for the same inlet-gas conditions and blade-jet speed ratio. If the basis for computing the isentropic power available to the turbine is the temperature inside the nozzle rather then the temperature in the inlet-gas pipe, an increase in turbine efficiency of about 0.01 is indicated.

  16. Real-time detection of axial force for reliable tightening control

    Science.gov (United States)

    Li, Chengzhou; Xu, Chao-Nan; Adachi, Yoshio; Ueno, Naohiro

    2010-03-01

    We developed a novel technique for bolt tightening control by utilizing SrAl2O4:Eu (SAOE) paint film to detect axial force generated during bolt tightening. Conventionally, torque method is prevalently used for bolt tightening control. The major problem of this method which indirectly controls the axial force in bolted joints is that only a small proportion of the torque actually contributes to the bolt extension. It is the axial force due to such an extension that fastens the bolted joints. Therefore, it is urgently necessary to directly measure the axial force in order to realize a smart tightening control. Considering the extension of bolt during tightening can induce elastico-luminescence of SAOE if it is painted on the bolt or washer, we have painted SAOE/polymer film on the washer and consequently measured elastico-luminescence of SAOE film while tightening the bolt under various conditions. In the present work, we also demonstrated the correlation between the elastico-luminescence intensity and tightening conditions including tightening speed and strain as well as axial force.

  17. Upregulation of matrix synthesis in chondrocyte-seeded agarose following sustained bi-axial cyclic loading

    Directory of Open Access Journals (Sweden)

    Belinda Pingguan-Murphy

    2012-08-01

    Full Text Available OBJECTIVES: The promotion of extracellular matrix synthesis by chondrocytes is a requisite part of an effective cartilage tissue engineering strategy. The aim of this in vitro study was to determine the effect of bi-axial cyclic mechanical loading on cell proliferation and the synthesis of glycosaminoglycans by chondrocytes in threedimensional cultures. METHOD: A strain comprising 10% direct compression and 1% compressive shear was applied to bovine chondrocytes seeded in an agarose gel during two 12-hour conditioning periods separated by a 12-hour resting period. RESULTS: The bi-axial-loaded chondrocytes demonstrated a significant increase in glycosaminoglycan synthesis compared with samples exposed to uni-axial or no loading over the same period (p<0.05. The use of a free-swelling recovery period prior to the loading regime resulted in additional glycosaminoglycan production and a significant increase in DNA content (p<0.05, indicating cell proliferation. CONCLUSIONS: These results demonstrate that the use of a bi-axial loading regime results in increased matrix production compared with uni-axial loading.

  18. Growth-induced axial buckling of a slender elastic filament embedded in an isotropic elastic matrix

    KAUST Repository

    O'Keeffe, Stephen G.

    2013-11-01

    We investigate the problem of an axially loaded, isotropic, slender cylinder embedded in a soft, isotropic, outer elastic matrix. The cylinder undergoes uniform axial growth, whilst both the cylinder and the surrounding elastic matrix are confined between two rigid plates, so that this growth results in axial compression of the cylinder. We use two different modelling approaches to estimate the critical axial growth (that is, the amount of axial growth the cylinder is able to sustain before it buckles) and buckling wavelength of the cylinder. The first approach treats the filament and surrounding matrix as a single 3-dimensional elastic body undergoing large deformations, whilst the second approach treats the filament as a planar, elastic rod embedded in an infinite elastic foundation. By comparing the results of these two approaches, we obtain an estimate of the foundation modulus parameter, which characterises the strength of the foundation, in terms of the geometric and material properties of the system. © 2013 Elsevier Ltd. All rights reserved.

  19. Studies of axial-leakage simulations for homogeneous and heterogeneous EBR-II core configurations

    Energy Technology Data Exchange (ETDEWEB)

    Grimm, K.N.; Meneghetti, D.

    1985-08-01

    When calculations of flux are done in less than three dimensions, leakage-absorption cross sections are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. Since the neutron flux is axially dependent, the leakages, and hence the leakage-absorption cross sections, are also axially dependent. Therefore, to obtain axial flux profiles (or reaction rates) for individual subassemblies, an XY-geometry calculation delineating each subassembly has to be done at several axial heights with space- and energy-dependent leakage-absorption cross sections that are appropriate for each height. This report discusses homogeneous and heterogeneous XY-geometry calculations at various axial locations and using several differing assumptions for the calculation of the leakage-absorption cross section. The positive (outward) leakage-absorption cross sections are modeled as actual leakage absorptions, but the negative (inward) leakage-absorption cross sections are modeled as either negative leakage absorptions (+-B/sup 2/ method) or positive downscatter cross sections (the ..sigma../sub s/(1 ..-->.. g) method). 3 refs., 52 figs., 10 tabs.

  20. Effects of the Tip Location on Single Piles Subjected to Surcharge and Axial Loads

    Directory of Open Access Journals (Sweden)

    Yaru Lv

    2013-01-01

    Full Text Available When applying axial load on piles subjected to negative skin friction (NSF, the yielded NSF is gradually eliminated. The process is notably influenced by the tip location (Y and still a lack of understanding. This paper reports three-dimensional numerical simulations with tip locations Y=1.00 pile diameter (D, 0.25D, 0.00D, and -1.00D. It is found that, against expectations, the dragload and NSF are not proportionally related to the tip location. When maximum dragload (Pmax is eventually eliminated due to an axial load, there is also a negative crest of the skin friction, indicating that NSF still exists based on the criterion of the dragload reduction. The side resistance of the piles with Y=1.00D and 0.25D is almost fully mobilised, which is demonstrated by the increment of end resistance that greatly increases with the larger axial loads. However, the side resistance of the piles with Y=0.00D and -1.00D has a potential capacity to carry more loads with continued displacement since the increment of end resistance increases almost linearly with axial load. Therefore, when designing the pile foundation, the inclusion of the NSF should be governed by the amount of axial load to be resisted.

  1. Effects of the tip location on single piles subjected to surcharge and axial loads.

    Science.gov (United States)

    Lv, Yaru; Ding, Xuanming; Wang, Dubo

    2013-01-01

    When applying axial load on piles subjected to negative skin friction (NSF), the yielded NSF is gradually eliminated. The process is notably influenced by the tip location (Y) and still a lack of understanding. This paper reports three-dimensional numerical simulations with tip locations Y = 1.00 pile diameter (D), 0.25D, 0.00D, and -1.00D. It is found that, against expectations, the dragload and NSF are not proportionally related to the tip location. When maximum dragload (P max) is eventually eliminated due to an axial load, there is also a negative crest of the skin friction, indicating that NSF still exists based on the criterion of the dragload reduction. The side resistance of the piles with Y = 1.00D and 0.25D is almost fully mobilised, which is demonstrated by the increment of end resistance that greatly increases with the larger axial loads. However, the side resistance of the piles with Y = 0.00D and -1.00D has a potential capacity to carry more loads with continued displacement since the increment of end resistance increases almost linearly with axial load. Therefore, when designing the pile foundation, the inclusion of the NSF should be governed by the amount of axial load to be resisted.

  2. A numerical study of the nonlinear dynamics of a light, axially moving band in surrounding fluid

    Science.gov (United States)

    Koivurova, H.; Laukkanen, J.

    2009-07-01

    The vibration characteristics of a submerged axially moving band are investigated by a numerical study. A geometrically nonlinear axially moving band model is coupled to the acoustic fluid model and the periodic nonlinear problem is solved by the Fourier-Galerkin-Newton (FGN) method. The nonlinear dynamic behaviour is examined through the dependences between fundamental frequency, axial velocity and the amplitude of nonlinear free vibration. The results are compared with the behaviour of an axially moving band in a vacuum as considered in the companion paper [H. Koivurova, Journal of Sound and Vibration 320 (2009) 373-385]. In the subcritical speed range the system behaved as expected, in that the effect of the surrounding air field reduced the fundamental frequency to about one fifth of the vibration observed in a vacuum. In the supercritical speed range the effects of the surrounding air depended on the amplitude of vibration and its change with increasing geometrical nonlinearity. With linear vibrations the fundamental frequency grows faster as a function of axial velocity than in vacuum, but with nonlinear vibrations the increase in frequency is slower than in a vacuum at near-critical velocities, but with a tendency to increase faster at higher velocities.

  3. Axial presacral lumbar interbody fusion and percutaneous posterior fixation for stabilization of lumbosacral isthmic spondylolisthesis.

    Science.gov (United States)

    Gerszten, Peter C; Tobler, William; Raley, Thomas J; Miller, Larry E; Block, Jon E; Nasca, Richard J

    2012-04-01

    Case series. To describe a minimally invasive surgical technique for treatment of lumbosacral spondylolisthesis. Traditional surgical management of lumbosacral spondylolisthesis is technically challenging and associated with significant complications. Minimally invasive surgical techniques offer patients treatment alternatives with lower operative morbidity risk. The combination of percutaneous pedicle screw reduction and an axial presacral approach for lumbosacral discectomy and fusion is an option for the surgical management of low-grade lumbosacral spondylolisthesis. Twenty-six consecutive patients with symptomatic L5-S1 level isthmic spondylolisthesis (grade 1 or grade 2) underwent axial presacral lumbar interbody fusion and percutaneous posterior fixation. Study outcomes included visual analogue scale for axial pain severity, Odom criteria, and radiographic fusion. The procedure was successfully completed in all patients with no intraoperative complications reported. Intraoperative blood loss was minimal (range, 20-150 mL). Median hospital stay was 1 day (range, Spondylolisthesis grade was improved after axial lumbar interbody fusion (Pradicular (n=2) or screw-related (n=2) pain. The minimally invasive presacral axial interbody fusion and posterior instrumentation technique is a safe and effective treatment for low-grade isthmic spondylolisthesis.

  4. Power Maneuvering of Pressurized Water Reactors with Axially Variable Strength Control Rods

    Science.gov (United States)

    Kim, Ung-Soo; Seong, Poong-Hyun

    2004-02-01

    In this research, axially variable strength control rods (AVSCRs) are developed to solve the problems related to the axial power distribution of a reactor during power maneuvering of pressurized water reactors (PWRs). The control rods are classified into two types: multipurpose control rods and regulating control rods. Two multipurpose control rod banks (AVSCR1, AVSCR2) are newly developed; conventional axially uniform strength control rods are adopted as regulating control rod banks to minimize the design change. The newly developed AVSCRs are axially three-sectioned and their worth shapes are optimized to obtain appropriate moving characteristics related to the variation of the axial offset (AO) according to the motion of the AVSCRs. The operation strategy for the power maneuvering is developed in consideration of the moving characteristics of the AVSCRs. This strategy consists of simple logics, and no use of reactivity compensation by boron is considered. Finally, the AVSCRs are applied to the power maneuvering with a typical 100-50-100%, 2-6-2-14 h pattern of daily load-follow for all burn-up state of the core. From the application results, it is shown that the use of AVSCRs makes it possible to regulate AO within the target band during the power maneuvering with only control rods. Consequently, power maneuvering is accomplished without reactivity compensation by a change in boron concentration, and the AVSCRs can cover the entire burn-up states of the reactor core.

  5. Experimental investigation on rectangular reinforced concrete beam subjected to bi-axial shear and torsion

    Directory of Open Access Journals (Sweden)

    Chayanon Hansapinyo

    2003-01-01

    Full Text Available This paper presents the experimental investigation on the failure mechanism and ultimate capacity of rectangular reinforced concrete beam under combined action of bi-axial shear accompanied with torsion through the test of four reinforced concrete members. The simple experimental set-up for a simply-supported beam under one point loading is introduced in this study by applying eccentric load to the tilted beam. This requires only one hydraulic jack to produce the complicated bi-axial shear and torsional loading. The main parameter is the magnitude of torsion induced to specimens which is relatively represented by the torsion-to-shear ratio. In addition, the influence of torsion on ultimate capacity of reinforced concrete with different ratio of two shears is investigated. From the experimental results, it is found that the increase in the magnitude of torsion about 69 percent drastically decreases bi-axial shear capacity as much as 12 to 39 percent according to the ratio of bi-axial shears. The experimental results are compared with the capacities calculated by the available interaction formula between uni-axial shear and torsion in the current design codes. The comparison indicates that the current design codes give quite conservative values of ultimate capacity.

  6. Characteristics of Modic changes in cervical kyphosis and their association with axial neck pain.

    Science.gov (United States)

    An, Yonghui; Li, Jia; Li, Yongqian; Shen, Yong

    2017-01-01

    The purpose of this study was to evaluate characteristics of Modic changes in cervical kyphosis (CK) and their association with axial neck pain. Study participants included 286 asymptomatic or symptomatic patients with CK (mean age = 54.2 ± 12.2 years) who were consecutively enrolled from March 2009 to October 2015. Clinical and radiographic evaluations were performed at a university outpatient department. CK was classified as global type, reverse sigmoid type, or sigmoid type. There were 138 participants with global type CK, 103 with reverse sigmoid type CK, and 45 with sigmoid type CK. Of the 286 participants, 102 had Modic changes (Modic-1 in 38 segments and Modic-2 in 75 segments). Spinal cord compression grade and disc degeneration occurred more frequently in the group with axial neck pain compared to the group without pain. Angular motion was decreased in those with axial neck pain (mean ± standard deviation [SD] 7.8°±4.6°) compared to those who were asymptomatic (mean ± SD 8.9°±5.1°; Plogistic regression analysis, Modic changes were associated with axial neck pain (odds ratio =5.356; 95% confidence interval =1.314-12.800; Preverse sigmoid type and sigmoid type. Modic changes are associated with axial neck pain in patients with CK.

  7. Random vibration analysis of axially compressed cylindrical shells under turbulent boundary layer in a symplectic system

    Science.gov (United States)

    Li, Yuyin; Zhang, Yahui; Kennedy, David

    2017-10-01

    A random vibration analysis of an axially compressed cylindrical shell under a turbulent boundary layer (TBL) is presented in the symplectic duality system. By expressing the cross power spectral density (PSD) of the TBL as a Fourier series in the axial and circumferential directions, the problem of structures excited by a random distributed pressure due to the TBL is reduced to solving the harmonic response function, which is the response of structures to a spatial and temporal harmonic pressure of unit magnitude. The governing differential equations of the axially compressed cylindrical shell are derived in the symplectic duality system, and then a symplectic eigenproblem is formed by using the method of separation of variables. Expanding the excitation vector and unknown state vector in symplectic space, decoupled governing equations are derived, and then the analytical solution can be obtained. In contrast to the modal decomposition method (MDM), the present method is formulated in the symplectic duality system and does not need modal truncation, and hence the computations are of high precision and efficiency. In numerical examples, harmonic response functions for the axially compressed cylindrical shell are studied, and a comparison is made with the MDM to verify the present method. Then, the random responses of the shell to the TBL are obtained by the present method, and the convergence problems induced by Fourier series expansion are discussed. Finally, influences of the axial compression on random responses are investigated.

  8. Fatigue Failure Results for Multi-Axial versus Uniaxial Stress Screen Vibration Testing

    Directory of Open Access Journals (Sweden)

    Wayne E. Whiteman

    2002-01-01

    Full Text Available To date, the failure potential and prediction between simultaneous multi-axial versus sequentially applied uniaxial vibration stress screen testing has been the subject of great debate. In most applications, current vibration tests are done by sequentially applying uniaxial excitation to the test specimen along three orthogonal axes. The most common standards for testing military equipment are published in MIL-STD-810F and NAVMAT P-9492. Previous research had shown that uniaxial testing may be unrealistic and inadequate. This current research effort is a continuing effort to systematically investigate the differences between fatigue damage mechanisms and the effects of uniaxial versus tri-axial testing. This includes assessing the ability of the tri-axial method in predicting the formation of damage mechanisms, specifically looking at the effects of stress or fatigue failure. Multi-axial testing achieves the synergistic effect of exciting all modes simultaneously and induces a more realistic vibration stress loading condition. As such, it better approximates real-world operating conditions. This paper provides the latest results on the differences between multi-axial and uniaxial testing of a simple notched cantilever beam.

  9. Effects of axial power shapes on CHF locations in a single tube and in rod bundle assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Han, B.; Yang, B.W.; Zhang, H.; Zha, Y.; Zhang, Y. [Xi' an Jiaotong Univ. (China). School of Nuclear Science and Technology

    2016-07-15

    Currently, the prediction of rod bundle CHF is dependent on CHF correlations derived from CHF data. A simple correction factor, such as F-factor, is often used to account for the axial power shape differences based on a simple accumulated energy concept, which has totally no consideration on the impact of true local condition on CHF mechanism. Subsequently, as expected, large uncertainty is often associated with the CHF value and CHF location predictions. For the purpose of obtaining different power shapes effects on CHF, CFD calculated parameter values were used to predict the possible CHF occurrence location. The possible CHF location prediction method proposed in this paper is calculated void fraction, heat transfer coefficient (HTC), liquid temperature distribution and detailed local parameters. And the uniform and non-uniform CHF were analyzed. The prediction of possible CHF locations in a 5 x 5 rod bundle may provide useful information for the design of a full-length CHF test, enhance the accuracy of CHF and CHF location prediction, and reduce the costs of the experimentation.

  10. Tip clearance effect on heat transfer and leakage flows on the shroud-wall surface in an axial flow turbine

    Science.gov (United States)

    Kumada, Masaya; Iwata, Satoshi; Obata, Masakazu; Watanabe, Osamu

    1992-06-01

    An axial flow turbine for a turbocharger is used as a test turbine, and the local heat transfer coefficient on the surface of the shroud is measured under uniform heat flux conditions. The nature of the tip clearance flow on the shroud surface and a flow pattern in the downstream region of the rotor blades are studied, and measurements are obtained by using a hot-wire anemometer in combination with a periodic multisampling and an ensemble averaging technique. Data are obtained under on- and off-design conditions. The effects of inlet flow angle, rotational speed and tip clearance on the local heat transfer coefficient are elucidated. The mean heat transfer coefficient is correlated with the tip clearance, and the mean velocity is calculated by the velocity triangle method for approximation. A leakage flow region exists in the downstream direction beyond the middle of the wall surface opposite the rotor blade, and a leakage vortex is recognized at the suction side near the trailing edge.

  11. The Johannesburg A-D circuit switch. A valve device for converting a co-axial Mapleson D into a co-axial Mapleson A system.

    Science.gov (United States)

    Manicom, A W; Schoonbee, C G

    1979-12-01

    A simple valve device is described for a co-axial tubing anaesthetic system which enables selection of the circuit characteristics of either a modified Mapleson A system for spontaneous breathing or a modified Mapleson D system for controlled ventilation. Thus, the system allows an economical fresh gas flow to be used during either controlled or spontaneous ventilation. The mode of ventilation may be changed during anaesthesia without adjusting the patient tubing or the attachment of the system to the anaesthetic machine.

  12. White matter biomarkers from fast protocols using axially symmetric diffusion kurtosis imaging

    CERN Document Server

    Hansen, Brian; Shemesh, Noam; Lund, Torben E; Sangill, Ryan; Østergaard, Leif; Jespersen, Sune N

    2016-01-01

    White matter tract integrity (WMTI) can be used to characterize tissue microstructure in areas with axisymmetric fiber bundles. Several WMTI biomarkers have now been validated against microscopy and provided promising results in studies of brain development and aging, as well as in a number of brain disorders. In a clinical setting, however, the diffusion kurtosis imaging (DKI) protocol utilized as part of WMTI imaging may be prohibitively long. Consequently, the diagnostic value of the WMTI parameters is rarely explored outside of dedicated animal studies and clinical studies of slowly progressing diseases. Here, we evaluate WMTI based on recently introduced axially symmetric DKI which has lower data demand than conventional DKI. We compare WMTI parameters derived from conventional DKI to those from axially symmetric DKI and to parameters calculated analytically from the axially symmetric tensors. We also assess the effect of the imposed symmetry on the kurtosis fractional anisotropy (KFA). We employ numeric...

  13. Fabrication and electrical properties of axial and radial GaAs nanowire pn junction diode arrays

    Science.gov (United States)

    Li, Jun-Shuai; Zhang, Xia; Yan, Xin; Chen, Xiong; Li, Liang; Cui, Jian-Gong; Huang, Yong-Qing; Ren, Xiao-Min

    2014-12-01

    We report on the fabrications and characterizations of axial and radial GaAs nanowire pn junction diode arrays. The nanowires are grown on n-doped GaAs (111)B substrates using the Au-catalyzed vapor—liquid—solid mechanism by metal—organic chemical vapor deposition (MOCVD). Diethyl—zinc and silane are used as p- and n-type dopant precursors, respectively. Both the axial and radial diodes exhibit diode-like J—V characteristics and have similar performances under forward bias. Under backward bias, the axial diode has a large leakage current, which is attributed to the bending of the pn junction interface induced by two doping mechanisms in Au-catalyzed nanowires. The low leakage current and high rectification ratio make the radial diode more promising in electrical and optoelectronic devices.

  14. In vivo multiphoton microscopy using a handheld scanner with lateral and axial motion compensation.

    Science.gov (United States)

    Sherlock, Ben; Warren, Sean C; Alexandrov, Yuriy; Yu, Fei; Stone, James; Knight, Jonathan; Neil, Mark A A; Paterson, Carl; French, Paul M W; Dunsby, Chris

    2017-08-31

    This paper reports a handheld multiphoton fluorescence microscope designed for clinical imaging that incorporates axial motion compensation and lateral image stabilization. Spectral domain optical coherence tomography is employed to track the axial position of the skin surface, and lateral motion compensation is realised by imaging the speckle pattern arising from the optical coherence tomography beam illuminating the sample. Our system is able to correct lateral sample velocities of up to approximately 65 μm s-1 . Combined with the use of negative curvature microstructured optical fibre to deliver tunable ultrafast radiation to the handheld multiphoton scanner without the need of a dispersion compensation unit, this instrument has potential for a range of clinical applications. The system is used to compensate for both lateral and axial motion of the sample when imaging human skin in vivo. © 2017 The Authors. Journal of Biophotonics published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Investigation of Axial Electric Field Measurements with Grounded-Wire TEM Surveys

    Science.gov (United States)

    Zhou, Nan-nan; Xue, Guo-qiang; Li, Hai; Hou, Dong-yang

    2017-09-01

    The grounded-wire transient electromagnetic (TEM) surveying is often performed along the equatorial direction with its observation lines paralleling to the transmitting wire with a certain transmitter-receiver distance. However, such method takes into account only the equatorial component of the electromagnetic field, and a little effort has been made on incorporating the other major component along the transmitting wire, here denoted as axial field. To obtain a comprehensive understanding of its fundamental characteristics and guide the designing of the corresponding observation system for reliable anomaly detection, this study for the first time investigates the axial electric field from three crucial aspects, including its decay curve, plane distribution, and anomaly sensitivity, through both synthetic modeling and real application to one major coal field in China. The results demonstrate a higher sensitivity to both high- and low-resistivity anomalies by the electric field in axial direction and confirm its great potentials for robust anomaly detection in the subsurface.

  16. The concept of a plasma centrifuge with a high frequency rotating magnetic field and axial circulation

    Science.gov (United States)

    Borisevich, V. D.; Potanin, E. P.

    2017-07-01

    The possibility of using a rotating magnetic field (RMF) in a plasma centrifuge (PC), with axial circulation to multiply the radial separation effect in an axial direction, is considered. For the first time, a traveling magnetic field (TMF) is proposed to drive an axial circulation flow in a PC. The longitudinal separation effect is calculated for a notional model, using specified operational parameters and the properties of a plasma, comprising an isotopic mixture of 20Ne-22Ne and generated by a high frequency discharge. The optimal intensity of a circulation flow, in which the longitudinal separation effect reaches its maximum value, is studied. The optimal parameters of the RMF and TMF for effective separation, as well as the centrifuge performance, are calculated.

  17. Developmental morphology of the axial skeleton of the zebrafish, Danio rerio (Ostariophysi: Cyprinidae).

    Science.gov (United States)

    Bird, Nathan C; Mabee, Paula M

    2003-11-01

    Before our rapidly increasing knowledge of gene interactions can be connected with the morphologic defects in mutant zebrafish, the normal course of skeletal development must be understood. Here, we describe the developmental morphology of the axial skeleton of zebrafish and review it in relation to the morphology of related species. The relative sequence of ossification in the skeleton is described. Two separate centers of development were found in the axial skeleton (Weberian apparatus and caudal fin) in contrast to tetrapods, which have a single anterior center. Slight variation was found in the overall relative timing of development. The extensive ichthyological literature on teleost anatomy and recent genetic data form the basis for our review and interpretation of homologies of various elements of the axial skeleton. Because homology forms the basis for all evolutionary comparisons, these data are critical for integration in evo-devo studies. Copyright 2003 Wiley-Liss, Inc.

  18. Axial offset as measure of stability of light water nuclear reactor during capacity maneuvering

    Directory of Open Access Journals (Sweden)

    Mark V. Nikolsky

    2015-03-01

    Full Text Available High reliability and security of power unit are required during operation of power unit while maneuvering. They depend on the stability of reactor when transition from one power level to another. The axial offset is a quantitative measure of the reactor stability. It is shown that change of the active core inlet coolant temperature yields an uncontrollable disturbance affecting the axial offset and therefore the reactor stability. To insure the reactor stability the compromise-combined power control method is proposed. Analysis of the influence of temperature of coolant at the magnitude of the axial offset for different regulatory programs is carried out. The change in the depth of immersion of regulators in the active zone for different regulatory programs when the reactor plant daily capacity maneuver is studied.

  19. Assessment of the impact of modeling axial compression on PET image reconstruction.

    Science.gov (United States)

    Belzunce, Martin A; Reader, Andrew J

    2017-10-01

    To comprehensively evaluate both the acceleration and image-quality impacts of axial compression and its degree of modeling in fully 3D PET image reconstruction. Despite being used since the very dawn of 3D PET reconstruction, there are still no extensive studies on the impact of axial compression and its degree of modeling during reconstruction on the end-point reconstructed image quality. In this work, an evaluation of the impact of axial compression on the image quality is performed by extensively simulating data with span values from 1 to 121. In addition, two methods for modeling the axial compression in the reconstruction were evaluated. The first method models the axial compression in the system matrix, while the second method uses an unmatched projector/backprojector, where the axial compression is modeled only in the forward projector. The different system matrices were analyzed by computing their singular values and the point response functions for small subregions of the FOV. The two methods were evaluated with simulated and real data for the Biograph mMR scanner. For the simulated data, the axial compression with span values lower than 7 did not show a decrease in the contrast of the reconstructed images. For span 11, the standard sinogram size of the mMR scanner, losses of contrast in the range of 5-10 percentage points were observed when measured for a hot lesion. For higher span values, the spatial resolution was degraded considerably. However, impressively, for all span values of 21 and lower, modeling the axial compression in the system matrix compensated for the spatial resolution degradation and obtained similar contrast values as the span 1 reconstructions. Such approaches have the same processing times as span 1 reconstructions, but they permit significant reduction in storage requirements for the fully 3D sinograms. For higher span values, the system has a large condition number and it is therefore difficult to recover accurately the higher

  20. Standard practice for conducting force controlled constant amplitude axial fatigue tests of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice covers the procedure for the performance of axial force controlled fatigue tests to obtain the fatigue strength of metallic materials in the fatigue regime where the strains are predominately elastic, both upon initial loading and throughout the test. This practice is limited to the fatigue testing of axial unnotched and notched specimens subjected to a constant amplitude, periodic forcing function in air at room temperature. This practice is not intended for application in axial fatigue tests of components or parts. Note 1-The following documents, although not directly referenced in the text, are considered important enough to be listed in this practice: E 739 Practice for Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain-Life (-N) Fatigue Data STP 566 Handbook of Fatigue Testing STP 588 Manual on Statistical Planning and Analysis for Fatigue Experiments STP 731 Tables for Estimating Median Fatigue Limits

  1. Evolution of axially symmetric anisotropic sources in f(R, T) gravity

    Energy Technology Data Exchange (ETDEWEB)

    Zubair, M. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Noureen, Ifra [University of Management and Technology, Department of Mathematics, Lahore (Pakistan)

    2015-06-15

    We discuss the dynamical analysis in f(R, T) gravity (where R is the Ricci scalar and T is the trace of the energy momentum tensor) for gravitating sources carrying axial symmetry. The self-gravitating system is taken to be anisotropic and the line element describes an axially symmetric geometry avoiding rotation about the symmetry axis and meridional motions (zero vorticity case). The modified field equations for axial symmetry in f(R, T) theory are formulated, together with the dynamical equations. Linearly perturbed dynamical equations lead to the evolution equation carrying the adiabatic index Γ, which defines the impact of a non-minimal matter to geometry coupling on the range of instability for Newtonian and post-Newtonian approximations. (orig.)

  2. Nonlinear output feedback control of underwater vehicle propellers using feedback form estimated axial flow velocity

    DEFF Research Database (Denmark)

    Fossen, T.I.; Blanke, M.

    2000-01-01

    Accurate propeller shaft speed controllers can be designed by using nonlinear control theory and feedback from the axial water velocity in the propeller disc. In this paper, an output feedback controller is derived, reconstructing the axial flow velocity from vehicle speed measurements, using...... a three-state model of propeller shaft speed, forward (surge) speed of the vehicle, and the axial flow velocity. Lyapunov stability theory is used to prove that a nonlinear observer combined with an output feedback integral controller provide exponential stability. The output feedback controller...... velocity can be estimated with good accuracy. In addition, the output feedback integral controller shows superior performance and robustness compared to a conventional shaft speed controller....

  3. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Directory of Open Access Journals (Sweden)

    Yi Sui

    2017-05-01

    Full Text Available A single-phase tubular permanent-magnet linear machine (PMLM with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA. The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  4. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Science.gov (United States)

    Sui, Yi; Liu, Yong; Cheng, Luming; Liu, Jiaqi; Zheng, Ping

    2017-05-01

    A single-phase tubular permanent-magnet linear machine (PMLM) with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA). The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  5. Application of Nonlocal Elasticity Shell Model for Axial Buckling of Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Farzad Khademolhosseini

    2009-10-01

    Full Text Available Recently, nano devices have been developed which use Carbon Nanotubes (CNTs as structural elements. To define the range of applicability of CNTs in such devices, it is important to investigate failure modes such as the axial buckling limit. Classical continuum models are inaccurate as they are unable to account for the size-effects in such devices. In this work, a modified nonlocal continuum shell model for the axial buckling of CNTs is proposed and compared with a nonlocal model for torsional buckling. This is done through modifying classical continuum models by incorporating basic concepts from nonlocal elasticity. Furthermore, molecular dynamics (MD simulations are performed on a range of nanotubes with different diameters. Compared to classical models, the modified nonlocal models provide a much better fit to MD simulation results. Using MD simulation results for axial buckling, values of the nonlocal constant and shell thickness are calculated.

  6. Clinical observation of micro-coaxial phacoemulsification for axial high myopia with cataract

    Directory of Open Access Journals (Sweden)

    Rui-Fan Zhang

    2014-11-01

    Full Text Available AIM: To observe the clinical effect of micro-coaxial phacoemulsification combined with intraocular lens implantation in axial high myopia with cataract.METHODS: Fifty-three patients(74 eyeswith axial high myopia and cataract underwent micro-coaxial phacoemulsification combined with intraocular lens implantation between April 2013 and December 2013. The best corrected visual acuity(BCVAwas observed at 1 and 3mo after operation, and the complications were recorded.RESULTS: Compared with the preoperative, BCVA was improved at 1 and 3mo after operation, and the differences were statistically significant(PP>0.05. There was no incidence of complications, such as retinal detachment, iris damage, pupil deformation, cystoid macular edema, endophthalmitis after operation in all patients.CONCLUSION:Micro-coaxial phacoemulsification combined with intraocular lens implantation is an effective and safe method for axial high myopia with cataract.

  7. Unusual dimeric tetrahydroxanthone derivatives from Aspergillus lentulus and the determination of their axial chiralities

    Science.gov (United States)

    Li, Tian-Xiao; Yang, Ming-Hua; Wang, Ying; Wang, Xiao-Bing; Luo, Jun; Luo, Jian-Guang; Kong, Ling-Yi

    2016-12-01

    The research on secondary metabolites of Aspergillus lentulus afforded eight unusual heterodimeric tetrahydroxanthone derivatives, lentulins A-H (2-9), along with the known compound neosartorin (1). Compounds 1-6 exhibited potent antimicrobial activities especially against methicillin-resistant Staphylococci. Their absolute configurations, particularly the axial chiralities, were unambiguously demonstrated by a combination of electronic circular dichroism (ECD), Rh2(OCOCF3)4-induced ECD experiments, modified Mosher methods, and chemical conversions. Interestingly, compounds 1-4 were the first samples of atropisomers within the dimeric tetrahydroxanthone class. Further investigation of the relationships between their axial chiralities and ECD Cotton effects led to the proposal of a specific CD Exciton Chirality rule to determine the axial chiralities in dimeric tetrahydroxanthones and their derivatives.

  8. Numerical Simulation of single-stage axial fan operation under dusty flow conditions

    Science.gov (United States)

    Minkov, L. L.; Pikushchak, E. V.

    2017-11-01

    Assessment of the aerodynamic efficiency of the single-stage axial flow fan under dusty flow conditions based on a numerical simulation using the computational package Ansys-Fluent is proposed. The influence of dust volume fraction on the dependences of the air volume flow rate and the pressure drop on the rotational speed of rotor is demonstrated. Matching functions for formulas describing a pressure drop and volume flow rate in dependence on the rotor speed and dust content are obtained by numerical simulation for the single-stage axial fan. It is shown that the aerodynamic efficiency of the single-stage axial flow fan decreases exponentially with increasing volume content of dust in the air.

  9. In vitro kinematics of the axially loaded ankle complex in response to dorsiflexion and plantarflexion.

    Science.gov (United States)

    Hintermann, B; Nigg, B M

    1995-08-01

    The rotational movements of the tibia and calcaneus that occur with dorsiflexion-plantarflexion and axial loading were studied in cadaver foot-leg specimens using an unconstrained testing apparatus. Independent of the foot flexion position, significant internal rotation of the tibia and eversion of the calcaneus were noted after the ankle complex was axially loaded. Independent of loading, 10 degrees of dorsiflexion resulted in 0.1 degrees of eversion and 2.1 degrees of internal rotation of the tibia. Conversely, 10 degrees of plantarflexion resulted in 1.6 degrees of inversion and 1.3 degrees of external rotation of the tibia. The induced rotational movements of the tibia and the calcaneus differed significantly between the specimens. These results suggest that the foot "axes" did not change by axially loading the ankle complex and they support previous reports that the ankle complex uses different axes for dorsiflexion and plantarflexion.

  10. An immediate effect of axial neck rotation training with real time visual feedback using a smartphone inclinometer on improvement in axial neck rotation function.

    Science.gov (United States)

    Park, Kyue-Nam; Kwon, Oh-Yun; Kim, Si-Hyun; Jeon, In-Cheol

    2017-03-01

    The purpose of this study was to compare the immediate effects of axial neck rotation training (Axi-NRT) with and without real-time visual feedback (VF) using a smartphone inclinometer on the range of motion (ROM) for axial neck rotation and the onset of compensatory neck lateral bending and extension during active neck rotation. Twenty participants with restricted ROM for neck rotation but no neck pain (21.1 ± 1.6 years and 8 males, 12 females) were recruited for Axi-NRT with VF, and twenty age- and gender-matched participants with restricted ROM for neck rotation were recruited for Axi-NRT without VF. Changes in ROM for neck rotation and the onset time of compensatory neck movement during active neck rotation were measured using an electromagnetic tracking system. Axi-NRT with VF was more effective in increasing ROM for neck rotation and decreasing and delaying the onset of compensatory neck movements during active neck rotation compared with Axi-NRT without VF. Repeated Axi-NRT using VF is useful to educate participants in maintaining the axis of the cervical spine and to increase ROM for axial neck rotation with less compensatory neck motion in participants with a restricted range of neck rotations.

  11. Production of low axial energy spread ion beams with multicusp sources

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yung -Hee Y. [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.

  12. Effect of Axial Force on the Performance of Micromachined Vibratory Rate Gyroscopes

    Directory of Open Access Journals (Sweden)

    Zhengyi Niu

    2010-12-01

    Full Text Available It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F beam and the other one was suspended with a clamped-clamped (C-C beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.

  13. Effect of axial force on the performance of micromachined vibratory rate gyroscopes.

    Science.gov (United States)

    Hou, Zhanqiang; Xiao, Dingbang; Wu, Xuezhong; Dong, Peitao; Chen, Zhihua; Niu, Zhengyi; Zhang, Xu

    2011-01-01

    It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F) beam and the other one was suspended with a clamped-clamped (C-C) beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF) due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.

  14. Axial growth and changes in lenticular and corneal power during emmetropization in infants.

    Science.gov (United States)

    Mutti, Donald O; Mitchell, G Lynn; Jones, Lisa A; Friedman, Nina E; Frane, Sara L; Lin, Wendy K; Moeschberger, Melvin L; Zadnik, Karla

    2005-09-01

    To evaluate the contribution made by the ocular components to the emmetropization of spherical equivalent refractive error in human infants between 3 and 9 months of age. Keratophakometry in two meridians was performed on 222 normal-birthweight infant subjects at 3 and 9 months of age. The spherical equivalent refractive error was measured by cycloplegic retinoscopy (cyclopentolate 1%). Anterior chamber depth, lens thickness, and vitreous chamber depth were measured by A-scan ultrasonography over the closed eyelid. Both the mean and SD for spherical equivalent refractive error decreased between 3 and 9 months of age (+2.16 +/- 1.30 D at 3 months; +1.36 +/- 1.06 D at 9 months; P < 0.0001, for the change in both mean and SD). Average ocular component change was characterized by increases in axial length, thinning, and flattening of the crystalline lens, increases in lens equivalent refractive index, and decreases in lens and corneal power. Initial refractive error was associated in a nonlinear manner with the change in refractive error (R(2) = 0.41; P < 0.0001) and with axial growth (R(2) = 0.082; P = 0.0005). Reduction in hyperopia correlated significantly with increases in axial length (R(2) = 0.16; P < 0.0001), but not with changes in corneal and lenticular power. Decreases in lenticular and corneal power were associated with axial elongation (R(2) = 0.40, R(2) = 0.12, respectively; both P < 0.0001). Modulation in the amount of axial growth in relation to initial refractive error appeared to be the most influential factor in emmetropization of spherical equivalent refractive error. The associations between initial refractive error, subsequent axial growth, and change in refractive error were consistent with a visual basis for emmetropization. The cornea and crystalline lens lost substantial amounts of dioptric power in this phase of growth, but neither appeared to play a significant role in emmetropization.

  15. Reduction of axial kinetic energy induced perturbations on observed cyclotron frequency.

    Science.gov (United States)

    Kaiser, Nathan K; Weisbrod, Chad R; Webb, Brian N; Bruce, James E

    2008-04-01

    With Fourier transform ion cyclotron resonance (FTICR) mass spectrometry one determines the mass-to-charge ratio of an ion by measuring its cyclotron frequency. However, the need to confine ions to the trapping region of the ion cyclotron resonance (ICR) cell with electric fields induces deviations from the unperturbed cyclotron frequency. Additional perturbations to the observed cyclotron frequency are often attributed to changes in space charge conditions. This study presents a detailed investigation of the observed ion cyclotron frequency as a function of ion z-axis kinetic energy. In a perfect three-dimensional quadrupolar field, cyclotron frequency is independent of position within the trap. However, in most ICR cell designs, this ideality is approximated only near the trap center and deviations arise from this ideal quadrupolar field as the ion moves both radially and axially from the center of the trap. To allow differentiation between deviations in observed cyclotron frequency caused from changes in space charge conditions or differences in oscillation amplitude, ions with identical molecular weights but different axial kinetic energy, and thus amplitude of z-axis motion, were simultaneously trapped within the ICR cell. This allows one to attribute deviations in observed cyclotron frequency to differences in the average force from the radial electric field experienced by ions of different axial amplitude. Experimentally derived magnetron frequency is compared with the magnetron frequency calculated using SIMION 7.0 for ions of different axial amplitude. Electron promoted ion coherence, or EPIC, is used to reduce the differences in radial electric fields at different axial positions. Thus with the application of EPIC, the differences in observed cyclotron frequencies are minimized for ions of different axial oscillation amplitudes.

  16. Diameter-dependent axial prestretch of porcine coronary arteries and veins

    Science.gov (United States)

    Guo, Xiaomei; Liu, Yi

    2012-01-01

    The pressure-diameter relation (PDR) and the wall strain of coronary blood vessels have important implications for coronary blood flow and arthrosclerosis, respectively. Previous studies have shown that these mechanical quantities are significantly affected by the axial stretch of the vessels. The objective of this study was to measure the physiological axial stretch in the coronary vasculature; i.e., from left anterior descending (LAD) artery tree to coronary sinus vein and to determine its effect on the PDR and hence wall stiffness. Silicone elastomer was perfused through the LAD artery and coronary sinus trees to cast the vessels at the physiologic pressure. The results show that the physiological axial stretch exists for orders 4 to 11 (> 24 μm in diameter) arteries and orders −4 to −12 (>38 μm in diameter) veins but vanishes for the smaller vessels. Statistically, the axial stretch is higher for larger vessels and is higher for arteries than veins. The axial stretch λz shows a linear variation with the order number (n) as: λz = 0.062n + 0.75 (R2 = 0.99) for artery and λz = −0.029n + 0.89 (R2 = 0.99) for vein. The mechanical analysis shows that the axial stretch significantly affects the PDR of the larger vessels. The circumferential stretch/strain was found to be significantly higher for the epicardial arteries (orders 9–11), which are free of myocardium constraint, than the intramyocardial arteries (orders 4–8). These findings have fundamental implications for coronary blood vessel mechanics. PMID:22162531

  17. Axial Region Optimization for Cycle Length Extension of Small Modular PWR

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Ji Won [UNIST, Ulsan (Korea, Republic of); Shin, Ho Cheol; Jung, Ji Eun [KHNP CRI, Daejeon (Korea, Republic of); Zheng, Youqi; Tak, Tae Woo; Lee, Deok Jung [UNIST, Ulsan (Korea, Republic of)

    2016-05-15

    This paper studied axial region sensitivity test in SMPWR to extend the cycle length. Zr- {sup 167}Er, Zr-B and Zr-Gd are used for BA material, the height of cutback and axial region has been changed. The cycle length of the reference core is 798 EFPD (26.6 EFPM), and there is no cutback and only {sup 167}Er-Zr is used in R-BA.Soluble boron-free small modular pressurized water reactor (SMPWR) can be a transportable size core due to the absence of the chemical volume control system (CVCS) and the amount of liquid radioactive waste, and further remove the corrosion problem caused by boric acid. The SMPWR needs large amount of burnable absorber (BA) instead of soluble boron, but the more the amount of BA is, the shorter the fuel cycle length is. Therefore, this paper studies axial region sensitivity test to make fuel cycle length of SMWPR longer. The procedure of axial region sensitivity test is as follows: cutback sensitivity tests, material and height sensitivity tests in the axial's reactor core design code system, has been used for these simulation. The optimal BA for cutback region is 10 cm of cutback with natural Gd 10 % in Zr-Gd, and the cycle length increases to 942 EFPD (31.4 months). Through the axial region sensitivity test, the cycle length becomes 1026 EFPD (34.2 months), but the peaking factors were not satisfied their limits. The 4.8-month increases compared with the reference core through the cutback sensitivity test. The possibility to excess reactivity with control rods in this core should verify.

  18. Personal A-constant in relation to axial length with various intraocular lenses

    Directory of Open Access Journals (Sweden)

    Mohamed A Eldaly

    2014-01-01

    Full Text Available Purpose: To study the relationship between the axial length and personal A-constant for the 1-piece Tecnis (Abbott ZCB00, AcrySof MA60AC (Alcon and the Quatrix aspheric preloaded (CROMA intraocular lenses (IOL. Materials and Methods: Patients matching the inclusion criteria were further subdivided according to the implanted IOL in this prospective comparative study. The obtained refractive outcomes were introduced into the formula installed in the biometry machine (Humphrey model 820 ultrasonic biometer to obtain the personal A-constant for each eye. Polynomial regression analysis was done to study the individualized A-constant for each type of IOL in relation to preoperative axial length measurement. Results: Two hundred and forty five eyes of 186 patients were enrolled into this study, of whom 73 eyes with Tecnis 1-piece, 116 eyes with MA60AC, and 56 eyes with Quatrix. The median of personalized A-constant for Tecnis 1-piece, MA60AC, and Quatrix were 119.21 (SD 1.3, Std. Mean error 0.15, 119 (SD 1.2, Std. Mean error 0.11 and 120.4 (SD 1.2, Std. Mean error 0.16 respectively. Regression plots for the same range of axial length among all the groups showed that the Tecnis1 group followed the same pattern of the Quatrix group in which there was a linear relationship of a trend towards myopia when the axial length had increased and a hyperopic shift when decreased. This relationship changed into a plateau when the axial length became in the range of 23.5 mm to 27 mm in the MA60AC group. Conclusions: Personal A-constant follows different trends with different IOLs even for the same range of axial length.

  19. Cellular structure of the healthy and keratoconic human cornea imaged in-vivo with sub-micrometer axial resolution OCT(Conference Presentation)

    Science.gov (United States)

    Bizheva, Kostadinka; Tan, Bingyao; Mason, Erik; Carter, Kirsten; Haines, Lacey; Sorbara, Luigina

    2017-02-01

    Keratoconus causes progressive morphological changes in the corneal epithelium (EPI), Bowman's membrane (BM) and anterior stroma. However, it is still not well understood if KC originates in the corneal epithelium and propagates to the anterior stroma through disruptions of the BM, or vice versa. In this study we used a sub-micrometer axial resolution OCT system to image in-vivo the cellular structure of the EPI layer and the fibrous structure of the BM and the anterior stroma in mild to advanced keratoconics, as well as healthy subjects. The imaging study was approved by the University of Waterloo Human Research Ethics Committee. The OCT system operates in the 800 nm spectral region at 34 kHz image acquisition rate and provides 0.95 um axial and < 2 um lateral resolution in corneal tissue, which is sufficient to visualize the cellular structure of the corneal epithelium and the fibrous structure of the BM. In some subjects, localized thinning and thickening of the EPI layer was observed, while there was no visible damage to the BM or anterior stroma. In other subjects, localized breakage of the stromal collagen fibrils was observed with no significant morphological changes of the corneal EPI.

  20. Eye size and shape in newborn children and their relation to axial length and refraction at 3 years.

    Science.gov (United States)

    Lim, Laurence Shen; Chua, Sharon; Tan, Pei Ting; Cai, Shirong; Chong, Yap-Seng; Kwek, Kenneth; Gluckman, Peter D; Fortier, Marielle V; Ngo, Cheryl; Qiu, Anqi; Saw, Seang-Mei

    2015-07-01

    To determine if eye size and shape at birth are associated with eye size and refractive error 3 years later. A subset of 173 full-term newborn infants from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort underwent magnetic resonance imaging (MRI) to measure the dimensions of the internal eye. Eye shape was assessed by an oblateness index, calculated as 1 - (axial length/width) or 1 - (axial length/height). Cycloplegic autorefraction (Canon Autorefractor RK-F1) and optical biometry (IOLMaster) were performed 3 years later. Both eyes of 173 children were analysed. Eyes with longer axial length at birth had smaller increases in axial length at 3 years (p Eyes with larger baseline volumes and surface areas had smaller increases in axial length at 3 years (p Eyes which were more oblate at birth had greater increases in axial length at 3 years (p eyes had smaller increases in axial length at 3 years compared to oblate eyes (p eyes had smaller increases in axial length at 3 years compared to oblate eyes (p eye size and shape at birth and refraction, corneal curvature or myopia at 3 years. Eyes that are larger and have prolate or spherical shapes at birth exhibit smaller increases in axial length over the first 3 years of life. Eye size and shape at birth influence subsequent eye growth but not refractive error development. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.