WorldWideScience

Sample records for trapped nonspherical birefringent

  1. Optical Forces on Non-Spherical Nanoparticles Trapped by Optical Waveguides

    Science.gov (United States)

    Hasan Ahmed, Dewan; Sung, Hyung Jin

    2011-07-01

    Numerical simulations of a solid-core polymer waveguide structure were performed to calculate the trapping efficiencies of particles with nanoscale dimensions smaller than the wavelength of the trapping beam. A three-dimensional (3-D) finite element method was employed to calculate the electromagnetic field. The inlet and outlet boundary conditions were obtained using an eigenvalue solver to determine the guided and evanescent mode profiles. The Maxwell stress tensor was considered for the calculation of the transverse and downward trapping efficiencies. A particle at the center of the waveguide showed minimal transverse trapping efficiency and maximal downward trapping efficiency. This trend gradually reversed as the particle moved away from the center of the waveguide. Particles with larger surface areas exhibited higher trapping efficiencies and tended to be trapped near the waveguide. Particles displaced from the wave input tended to be trapped at the waveguide surface. Simulation of an ellipsoidal particle showed that the orientation of the major axis along the waveguide's lateral z-coordinate significantly influenced the trapping efficiency. The particle dimensions along the z-coordinate were more critical than the gap distance (vertical displacement from the floor of the waveguide) between the ellipsoid particle and the waveguide. The present model was validated using the available results reported in the literature for different trapping efficiencies.

  2. Nonspherical oscilllations of ultrasound contrast agent microbubbles

    NARCIS (Netherlands)

    Dollet, B.; van der Meer, S.M.; Garbin, V.; Garbin, Valeria; de Jong, N.; Lohse, Detlef; Versluis, Michel

    2008-01-01

    The occurrence of nonspherical oscillations (or surface modes) of coated microbubbles, used as ultrasound contrast agents in medical imaging, is investigated using ultra–high-speed optical imaging. Optical tweezers designed to micromanipulate single bubbles in 3-D are used to trap the bubbles far

  3. Birefringent hollow core fibers

    DEFF Research Database (Denmark)

    Roberts, John

    2007-01-01

    Hollow core photonic crystal fiber (HC-PCF), fabricated according to a nominally non-birefringent design, shows a degree of un-controlled birefringence or polarization mode dispersion far in excess of conventional non polarization maintaining fibers. This can degrade the output pulse in many...... applications, and places emphasis on the development of polarization maintaining (PM) HC-PCF. The polarization cross-coupling characteristics of PM HC-PCF are very different from those of conventional PM fibers. The former fibers have the advantage of suffering far less from stress-field fluctuations...... and an increased overlap between the polarization modes at the glass interfaces. The interplay between these effects leads to a wavelength for optimum polarization maintenance, lambda(PM), which is detuned from the wavelength of highest birefringence. By a suitable fiber design involving antiresonance of the core...

  4. Nonperturbative QED vacuum birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, V.I.; Dolgaya, E.E.; Sokolov, V.A. [Physics Department, Moscow State University,Moscow, 119991 (Russian Federation)

    2017-05-19

    In this paper we represent nonperturbative calculation for one-loop Quantum Electrodynamics (QED) vacuum birefringence in presence of strong magnetic field. The dispersion relations for electromagnetic wave propagating in strong magnetic field point to retention of vacuum birefringence even in case when the field strength greatly exceeds Sauter-Schwinger limit. This gives a possibility to extend some predictions of perturbative QED such as electromagnetic waves delay in pulsars neighbourhood or wave polarization state changing (tested in PVLAS) to arbitrary magnetic field values. Such expansion is especially important in astrophysics because magnetic fields of some pulsars and magnetars greatly exceed quantum magnetic field limit, so the estimates of perturbative QED effects in this case require clarification.

  5. Birefringent phononic structures

    Directory of Open Access Journals (Sweden)

    I. E. Psarobas

    2014-12-01

    Full Text Available Within the framework of elastic anisotropy, caused in a phononic crystal due to low crystallographic symmetry, we adopt a model structure, already introduced in the case of photonic metamaterials, and by analogy, we study the effect of birefringence and acoustical activity in a phononic crystal. In particular, we investigate its low-frequency behavior and comment on the factors which determine chirality by reference to this model.

  6. Birefringent coherent diffraction imaging

    Science.gov (United States)

    Karpov, Dmitry; dos Santos Rolo, Tomy; Rich, Hannah; Kryuchkov, Yuriy; Kiefer, Boris; Fohtung, E.

    2016-10-01

    Directional dependence of the index of refraction contains a wealth of information about anisotropic optical properties in semiconducting and insulating materials. Here we present a novel high-resolution lens-less technique that uses birefringence as a contrast mechanism to map the index of refraction and dielectric permittivity in optically anisotropic materials. We applied this approach successfully to a liquid crystal polymer film using polarized light from helium neon laser. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of emergent brilliant X-ray sources. Applications of this novel imaging technique are in disruptive technologies, including novel electronic devices, in which both charge and spin carry information as in multiferroic materials and photonic materials such as light modulators and optical storage.

  7. Hypostatic jammed packings of frictionless nonspherical particles

    OpenAIRE

    VanderWerf, Kyle; Jin, Weiwei; Shattuck, Mark D.; O'Hern, Corey S.

    2017-01-01

    We perform computational studies of static packings of a variety of nonspherical particles including circulo-lines, circulo-polygons, ellipses, asymmetric dimers, and dumbbells to determine which shapes form hypostatic versus isostatic packings and to understand why hypostatic packings of nonspherical particles can be mechanically stable despite having fewer contacts than that predicted from na\\"ive constraint counting. To generate highly accurate force- and torque-balanced packings of circul...

  8. Zero-birefringence pressure-sensitive adhesives

    Directory of Open Access Journals (Sweden)

    Hiroto Ito

    2012-06-01

    Full Text Available We have developed zero-birefringence pressure-sensitive adhesives (PSAs that exhibit almost no birefringence at any orientation of polymer chains. To evaluate the birefringence of PSAs quantitatively, we report a novel birefringence-measurement method utilizing zero–zero-birefringence polymers that exhibit no birefringence at any orientation of polymer chains and in elastic deformation. By employing this method, we designed and synthesized poly(butyl acrylate/phenoxyethyl acrylate/acrylic acid/hydroxyethyl acrylate = 80.0:20.0:1.5:1.0 (by weight that contains 1.8 wt% isocyanate-type crosslinker that exhibited almost zero birefringence. Furthermore, we demonstrated that after the accelerated aging test by applying heat, this zero-birefringence PSA almost completely prevented light leakage through crossed polarizers.

  9. Scattering of light by nonspherical particles

    International Nuclear Information System (INIS)

    Coulson, K.L.

    1985-12-01

    Methods of computing scattering by non-spherical particles are reviewed for the Mie theory, the Rayleigh-Gans approximation, the geometric optics method, the extended boundary condition method, the anamalous diffraction, the suppression of resonances, the statistical approach, the expansion of vector wave equations in spheroidal coordinates, and the semi-emperical theory of Pollack and Cuzzi. The results of computations for nonspherical particles are compared for prolate and oblate spheroids, homogeneous sphere with holes, rough particles made of stacked cylinders, irregular particles of various shapes, and particles of carbonaceous smokes. Conclusions are presented in the context of nuclear winter

  10. Charging of nonspherical macroparticles in a plasma

    Science.gov (United States)

    Holgate, J. T.; Coppins, M.

    2016-03-01

    The current theories of macroparticle charging in a plasma are limited to spheres, and are unsuitable for the multitude of nonspherical objects existing in astrophysical, atmospheric, laboratory, and fusion plasmas. This paper extends the most widely used spherical charging theory, orbit motion limited theory, to spheroids and, as such, provides a comprehensive study of the charging of nonspherical objects in a plasma. The spherical charging theory is shown to be a reasonable approximation for a considerable range of spheroids. However, the electric potential of highly elongated spheroids can be almost twice the spherical value. Furthermore, the total charge on the spheroids increases by a significantly larger factor than their potential.

  11. High-birefringent photonic crystal fiber

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou; Broeng, Jes; Knudsen, Erik

    2001-01-01

    A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber.......A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber....

  12. Hypostatic jammed packings of frictionless nonspherical particles

    Science.gov (United States)

    VanderWerf, Kyle; Jin, Weiwei; Shattuck, Mark D.; O'Hern, Corey S.

    2018-01-01

    We perform computational studies of static packings of a variety of nonspherical particles including circulo-lines, circulo-polygons, ellipses, asymmetric dimers, dumbbells, and others to determine which shapes form packings with fewer contacts than degrees of freedom (hypostatic packings) and which have equal numbers of contacts and degrees of freedom (isostatic packings), and to understand why hypostatic packings of nonspherical particles can be mechanically stable despite having fewer contacts than that predicted from naive constraint counting. To generate highly accurate force- and torque-balanced packings of circulo-lines and cir-polygons, we developed an interparticle potential that gives continuous forces and torques as a function of the particle coordinates. We show that the packing fraction and coordination number at jamming onset obey a masterlike form for all of the nonspherical particle packings we studied when plotted versus the particle asphericity A , which is proportional to the ratio of the squared perimeter to the area of the particle. Further, the eigenvalue spectra of the dynamical matrix for packings of different particle shapes collapse when plotted at the same A . For hypostatic packings of nonspherical particles, we verify that the number of "quartic" modes along which the potential energy increases as the fourth power of the perturbation amplitude matches the number of missing contacts relative to the isostatic value. We show that the fourth derivatives of the total potential energy in the directions of the quartic modes remain nonzero as the pressure of the packings is decreased to zero. In addition, we calculate the principal curvatures of the inequality constraints for each contact in circulo-line packings and identify specific types of contacts with inequality constraints that possess convex curvature. These contacts can constrain multiple degrees of freedom and allow hypostatic packings of nonspherical particles to be mechanically

  13. Torsional Optomechanics of a Levitated Nonspherical Nanoparticle

    Science.gov (United States)

    Hoang, Thai M.; Ma, Yue; Ahn, Jonghoon; Bang, Jaehoon; Robicheaux, F.; Yin, Zhang-Qi; Li, Tongcang

    2016-09-01

    An optically levitated nanoparticle in vacuum is a paradigm optomechanical system for sensing and studying macroscopic quantum mechanics. While its center-of-mass motion has been investigated intensively, its torsional vibration has only been studied theoretically in limited cases. Here we report the first experimental observation of the torsional vibration of an optically levitated nonspherical nanoparticle in vacuum. We achieve this by utilizing the coupling between the spin angular momentum of photons and the torsional vibration of a nonspherical nanoparticle whose polarizability is a tensor. The torsional vibration frequency can be 1 order of magnitude higher than its center-of-mass motion frequency, which is promising for ground state cooling. We propose a simple yet novel scheme to achieve ground state cooling of its torsional vibration with a linearly polarized Gaussian cavity mode. A levitated nonspherical nanoparticle in vacuum will also be an ultrasensitive nanoscale torsion balance with a torque detection sensitivity on the order of 10-29 N m /√{Hz } under realistic conditions.

  14. Non-Spherical Gravitational Collapse of Strange Quark Matter

    Institute of Scientific and Technical Information of China (English)

    Zade S S; Patil K D; Mulkalwar P N

    2008-01-01

    We study the non-spherical gravitational collapse of the strange quark null fluid.The interesting feature which emerges is that the non-spherical collapse of charged strange quark matter leads to a naked singularity whereas the gravitational collapse of neutral quark matter proceeds to form a black hole.We extend the earlier work of Harko and Cheng[Phys.Lett.A 266 (2000) 249]to the non-spherical case.

  15. Non-spherical granular flows down inclined chutes

    NARCIS (Netherlands)

    Hidalgo, R.C.; Rubio-Largo, S.M.; Alonso-Marroquin, F.; Weinhart, T.

    2017-01-01

    In this work, we numerically examine the steady-state granular flow of 3D non-spherical particles down an inclined plane. We use a hybrid CPU/GPU implementation of the discrete element method of nonspherical elongated particles. Thus, a systematic study of the system response is performed varying

  16. Effect of particle nonsphericity on bidirectional reflectance of cirrus clouds

    Energy Technology Data Exchange (ETDEWEB)

    Mishchenko, M.I.; Rossow, W.B.; Macke, A.; Lacis, A.A. [Goddard Institute for Space Studies, New York, NY (United States)

    1996-04-01

    This paper describes the use of the fractal ice particle method to study the differences in bidirectional reflectance caused by the differences in the single scattering phase functions of spherical water droplets and nonspherical ice crystals.

  17. Turbulence Modulation by Non-Spherical Particles

    DEFF Research Database (Denmark)

    Mandø, Matthias

    This study deals with the interaction between turbulence and non-spherical particles and represents an extension of the modeling framework for particleladen flows. The effect of turbulence on particles is commonly referred to as turbulent dispersion while the effect of particles on the carrier....... This study encompass an outlook on existing work, an experimental study, development of a numerical model and a case study advancing the modeling techniques for pulverized coal combustion to deal with larger non-spherical biomass particles. Firstly, existing knowledge concerning the motion of non......-spherical particles and turbulence modulation are outlined. A complete description of the motion of non-spherical particles is still lacking. However, evidence suggests that the equation of motion for a sphere only represent an asymptotical value for a more general, but yet unformulated, description of the motion...

  18. Saltation of non-spherical sand particles.

    Directory of Open Access Journals (Sweden)

    Zhengshi Wang

    Full Text Available Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement.

  19. Electro-optical tunable birefringent filter

    Science.gov (United States)

    Levinton, Fred M [Princeton, NJ

    2012-01-31

    An electrically tunable Lyot type filter is a Lyot that include one or more filter elements. Each filter element may have a planar, solid crystal comprised of a material that exhibits birefringence and is electro-optically active. Transparent electrodes may be coated on each face of the crystal. An input linear light polarizer may be located on one side of the crystal and oriented at 45 degrees to the optical axis of the birefringent crystal. An output linear light polarizer may be located on the other side of the crystal and oriented at -45 degrees with respect to the optical axis of the birefringent crystal. When an electric voltage is applied between the electrodes, the retardation of the crystal changes and so does the spectral transmission of the optical filter.

  20. Crystallographic cut that maximizes of the birefringence in photorefractive crystals

    OpenAIRE

    Rueda-Parada, Jorge Enrique

    2017-01-01

    The electro-optical birefringence effect depends on the crystal type, cut crystal, applied electric field and the incidence direction of light on the principal crystal faces. It is presented a study of maximizing the birefringence in photorefractive crystals of cubic crystallographic symmetry, in terms of these three parameters. General analytical expressions for the birefringence were obtained, from which birefringence can be established for any type of cut. A new crystallographic cut was en...

  1. Measurement of Turbulence Modulation by Non-Spherical Particles

    DEFF Research Database (Denmark)

    Mandø, Matthias; Rosendahl, Lasse

    2010-01-01

    The change in the turbulence intensity of an air jet resulting from the addition of particles to the flow is measured using Laser Doppler Anemometry. Three distinct shapes are considered: the prolate spheroid, the disk and the sphere. Measurements of the carrier phase and particle phase velocities...... at the centerline of the jet are carried out for mass loadings of 0.5, 1, 1.6 and particle sizes 880μm, 1350μm, 1820μm for spherical particles. For each non-spherical shape only a single size and loading are considered. The turbulence modulation of the carrier phase is found to highly dependent on the turbulence......, the particle mass flow and the integral length scale of the flow. The expression developed on basis of spherical particles only is applied on the data for the non-spherical particles. The results suggest that non-spherical particles attenuate the carrier phase turbulence significantly more than spherical...

  2. Gravitational agglomeration of post-HCDA LMFBR aerosols: nonspherical particles

    International Nuclear Information System (INIS)

    Tuttle, R.F.; Loyalka, S.K.

    1982-12-01

    Aerosol behavior analysis computer programs have shown that temporal aerosol size distributions in nuclear reactor containments are sensitive to shape factors. This research investigates shape factors by a detailed theoretical analysis of hydrodynamic interactions between a nonspherical particle and a spherical particle undergoing gravitational collisions in an LMFBR environment. First, basic definitions and expressions for settling speeds and collisional efficiencies of nonspherical particles are developed. These are then related to corresponding quantities for spherical particles through shape factors. Using volume equivalent diameter as the defining length in the gravitational collision kernel, the aerodynamic shape factor, the density correction factor, and the gravitational collision shape factor, are introduced to describe the collision kernel for collisions between aerosol agglomerates. The Navier-Stokes equation in oblate spheroidal coordinates is solved to model a nonspherical particle and then the dynamic equations for two particle motions are developed. A computer program (NGCEFF) is constructed, and the dynamical equations are solved by Gear's method

  3. Non-Spherical Microcapsules for Increased Core Content Volume Delivery

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    The goal of this project was to advance microencapsulation from the standard spherical microcapsule to a non-spherical, high-aspect ratio (HAR), elongated microcapsule. This was to be accomplished by developing reproducible methods of synthesizing or fabricating robust, non-spherical, HAR microcapsules. An additional goal of this project was to develop the techniques to the point where scale-up of these methods could be examined. Additionally, this project investigated ways to apply the microencapsulation techniques developed as part of this project to self-healing formulations.

  4. Parametric resonance in quantum electrodynamics vacuum birefringence

    Science.gov (United States)

    Arza, Ariel; Elias, Ricardo Gabriel

    2018-05-01

    Vacuum magnetic birefringence is one of the most interesting nonlinear phenomena in quantum electrodynamics because it is a pure photon-photon result of the theory and it directly signalizes the violation of the classical superposition principle of electromagnetic fields in the full quantum theory. We perform analytical and numerical calculations when an electromagnetic wave interacts with an oscillating external magnetic field. We find that in an ideal cavity, when the external field frequency is around the electromagnetic wave frequency, the normal and parallel components of the wave suffer parametric resonance at different rates, producing a vacuum birefringence effect growing in time. We also study the case where there is no cavity and the oscillating magnetic field is spatially localized in a region of length L . In both cases we find also a rotation of the elliptical axis.

  5. Transient birefringence effects in electromagnetically induced transparency

    International Nuclear Information System (INIS)

    Parshkov, O M

    2015-01-01

    We report the results of numerical modelling of transient birefringence that arises as a result of electromagnetically induced transparency on degenerate quantum transitions between the states with J = 0, 1 and 2 in the presence of the Doppler broadening of spectral lines. It is shown that in the case of a linearly polarised control field, the effect of transient birefringence leads to a decay of the input circularly polarised probe pulse into separate linearly polarised pulses inside a medium. In the case of a circularly polarised control field, the effect of transient birefringence manifests itself in a decay of the input linearly polarised probe pulse into separate circularly polarised pulses. It is shown that the distance that a probe pulse has to pass in a medium before decaying into subpulses is considerably greater in the first case than in the second. The influence of the input probe pulse power and duration on the process of spatial separation into individual pulses inside a medium is studied. A qualitative analysis of the obtained results is presented. (nonlinear optical phenomena)

  6. The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

    Energy Technology Data Exchange (ETDEWEB)

    Della Valle, Federico; Milotti, Edoardo [INFN, Trieste (Italy); Universita di Trieste, Dipt. di Fisica, Trieste (Italy); Ejlli, Aldo; Messineo, Giuseppe; Zavattini, Guido [INFN, Ferrara (Italy); Universita di Ferrara, Dipt. di Fisica e Scienze della Terra, Ferrara (Italy); Gastaldi, Ugo [INFN, Ferrara (Italy); Pengo, Ruggero; Ruoso, Giuseppe [INFN, Lab. Nazionale di Legnaro, Legnaro (Italy)

    2016-01-15

    Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides a new limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge. (orig.)

  7. Detecting strain in birefringent materials using spectral polarimetry

    Science.gov (United States)

    Garner, Harold R. (Inventor); Ragucci, Anthony J. (Inventor); Cisar, Alan J. (Inventor); Huebschman, Michael L. (Inventor)

    2010-01-01

    A method, computer program product and system for analyzing multispectral images from a plurality of regions of birefringent material, such as a polymer film, using polarized light and a corresponding polar analyzer to identify differential strain in the birefringent material. For example, the birefringement material may be low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinylidene chloride, polyester, nylon, or cellophane film. Optionally, the method includes generating a real-time quantitative strain map.

  8. On the phase diagram of non-spherical nanoparticles

    CERN Document Server

    Wautelet, M; Hecq, M

    2003-01-01

    The phase diagram of nanoparticles is known to be a function of their size. In the literature, this is generally demonstrated for cases where their shape is spherical. Here, it is shown theoretically that the phase diagram of non-spherical particles may be calculated from the spherical case, at the same surface area/volume ratio, both with and without surface segregation, provided the surface tension is considered to be isotropic.

  9. Experiment to measure vacuum birefringence: Conceptual design

    Science.gov (United States)

    Mueller, Guido; Tanner, David; Doebrich, Babette; Poeld, Jan; Lindner, Axel; Willke, Benno

    2016-03-01

    Vacuum birefringence is another lingering challenge which will soon become accessible to experimental verification. The effect was first calculated by Euler and Heisenberg in 1936 and is these days described as a one-loop correction to the differential index of refraction between light which is polarized parallel and perpendicular to an external magnetic field. Our plan is to realize (and slightly modify) an idea which was originally published by Hall, Ye, and Ma using advanced LIGO and LISA technology and the infrastructure of the ALPS light-shining-through-walls experiment following the ALPS IIc science run. This work is supported by the Deutsche Forschungsgemeinschaft and the Heising-Simons Foundation.

  10. Anomalously temperature-independent birefringence in biaxial optical crystals

    International Nuclear Information System (INIS)

    Grechin, Sergei G; Dmitriev, Valentin G; Dyakov, Vladimir A; Pryalkin, Vladimir I

    2000-01-01

    Temperature-independent birefringence in a biaxial crystal was predicted theoretically and observed experimentally for the first time. The width of the plot against temperature (the range corresponding to the temperature independence of the birefringence) at a fundamental radiation wavelength of 632.8 nm in a KTP crystal 5.9 mm long was more than 160 0 C. (letters to the editor)

  11. Sensing characteristics of birefringent microstructured polymer optical fiber

    DEFF Research Database (Denmark)

    Szczurowski, Marcin K.; Frazao, Orlando; Baptista, J. M.

    2011-01-01

    We experimentally studied several sensing characteristics of a birefringent microstructured polymer optical fiber. The fiber exhibits a birefringence of the order 2×10-5 at 1.3 μm because of two small holes adjacent to the core. In this fiber, we measured spectral dependence of phase and group mo...

  12. Polarization Converter with Controllable Birefringence Based on Hybrid All-Dielectric-Graphene Metasurface

    Science.gov (United States)

    Owiti, Edgar O.; Yang, Hanning; Liu, Peng; Ominde, Calvine F.; Sun, Xiudong

    2018-02-01

    Previous studies on hybrid dielectric-graphene metasurfaces have been used to implement induced transparency devices, while exhibiting high Q-factors based on trapped magnetic resonances. Typically, the transparency windows are single wavelength and less appropriate for polarization conversion structures. In this work, a quarter-wave plate based on a hybrid silicon-graphene metasurface with controllable birefringence is numerically designed. The phenomena of trapped magnetic mode resonance and high Q-factors are modulated by inserting graphene between silicon and silica. This results in a broader transmission wavelength in comparison to the all-dielectric structure without graphene. The birefringence tunability is based on the dimensions of silicon and the Fermi energy of graphene. Consequently, a linear-to-circular polarization conversion is achieved at a high degree of 96%, in the near-infrared. Moreover, the polarization state of the scattered light is switchable between right and left hand circular polarizations, based on an external gate biasing voltage. Unlike in plasmonic metasurfaces, these achievements demonstrate an efficient structure that is free from radiative and ohmic losses. Furthermore, the ultrathin thickness and the compactness of the structure are demonstrated as key components in realizing integrable and CMOS compatible photonic sensors.

  13. Fabrication of birefringent nanocylinders for single-molecule force and torque measurement

    Science.gov (United States)

    Li, Ping-Chun; Chang, Jen-Chien; La Porta, Arthur; Yu, Edward T.

    2014-06-01

    Optically anisotropic subwavelength scale dielectric particles have been shown to enable studies of the mechanical properties of bio-molecules via optical trapping and manipulation. However, techniques emphasized to date for fabrication of such particles generally suffer from limited uniformity and control over particle dimensions, or low throughput and high cost. Here, an approach for rapid, low-cost, fabrication of large quantities of birefringent quartz nanocylinders with dimensions optimized for optical torque wrench experiments is described. For a typical process, 108 or more quartz cylinders with diameters of 500 nm and heights of 800 nm, with uniformity of ±5% in each dimension, can be fabricated over ˜10 cm2 areas, for binding to a single bio-molecule, and harvested for use in optical trapping experiments. Use of these structures to measure extensional and torsional dynamics of single DNA molecules is demonstrated with measured forces and torques shown to be in very good agreement with previously reported results.

  14. Fabrication of birefringent nanocylinders for single-molecule force and torque measurement

    International Nuclear Information System (INIS)

    Li, Ping-Chun; T Yu, Edward; Chang, Jen-Chien; La Porta, Arthur

    2014-01-01

    Optically anisotropic subwavelength scale dielectric particles have been shown to enable studies of the mechanical properties of bio-molecules via optical trapping and manipulation. However, techniques emphasized to date for fabrication of such particles generally suffer from limited uniformity and control over particle dimensions, or low throughput and high cost. Here, an approach for rapid, low-cost, fabrication of large quantities of birefringent quartz nanocylinders with dimensions optimized for optical torque wrench experiments is described. For a typical process, 10 8 or more quartz cylinders with diameters of 500 nm and heights of 800 nm, with uniformity of ±5% in each dimension, can be fabricated over ∼10 cm 2 areas, for binding to a single bio-molecule, and harvested for use in optical trapping experiments. Use of these structures to measure extensional and torsional dynamics of single DNA molecules is demonstrated with measured forces and torques shown to be in very good agreement with previously reported results. (papers)

  15. Phases of dense matter with non-spherical nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pethick, C J [NORDITA, Copenhagen (Denmark); [Dept. of Physics, Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States); Ravenhall, D G [Dept. of Physics, Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)

    1998-06-01

    A brief review is given of some of the important physics related to phases with non-spherical nuclei that can exist in neutron stars and in matter in stellar collapse at densities just below the saturation density of nuclear matter. Comparisons are made with other systems that exhibit similar liquid-crystal-like phases, both in nuclear physics and in condensed matter physics. A short account is given of recent work on the elastic properties of these phases, and their vibration spectrum, as well as on neutron superfluid gaps. (orig.)

  16. Collective states of nonspherical deformable even--even nuclei

    International Nuclear Information System (INIS)

    Tartakovskii, V.K.

    1989-01-01

    A more correct method, as compared with some earlier studies, of finding the wave functions and corresponding energies of longitudinal quadrupole vibrations of nonspherical even--even nuclei is proposed. The wave functions and energies of collective motions in nuclei have been obtained in explicit form for a number of dependences of the potential energy of longitudinal vibrations V(β), including the dependence V(β), not previously used, of the most general form. Explicit dependences of the potential energy of transverse vibrations and the corresponding wave functions and eigenvalues for nuclear states with zero spins are proposed

  17. Note: Ultra-low birefringence dodecagonal vacuum glass cell

    Energy Technology Data Exchange (ETDEWEB)

    Brakhane, Stefan, E-mail: brakhane@iap.uni-bonn.de; Alt, Wolfgang; Meschede, Dieter; Robens, Carsten; Moon, Geol; Alberti, Andrea [Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, D-53115 Bonn (Germany)

    2015-12-15

    We report on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence Δn of each window with the cell under vacuum conditions, obtaining values around 10{sup −8}. After baking the cell at 150 °C, we reach a pressure below 10{sup −10} mbar. In addition, each window is antireflection coated on both sides, which is highly desirable for quantum optics experiments and precision measurements.

  18. Linear birefringence and optical ativity in a magnetized plasma

    International Nuclear Information System (INIS)

    Vuolo, J.H.; Galvao, R.M.O.

    1982-02-01

    Linear birefringence and optical activity are considered separately to electromagnetic wave propagation in magnetized cold plasma, using frequency approximation much bigger than plasma frequency. It's showen that in some interesting cases, those phenomena could be independents. Explicit expressions are obtained for refraction indices to linear birefringency and optical activity. The correspondents indices attenuation aRe obtained in first orden of attenuation. It's showen that the characteristic states for linear dichroism coincide with the characteristic states for linear birefringence. The characteristic states for elliptic dichroism are obtained. (M.A.F.) [pt

  19. Magnetic particle tracking for nonspherical particles in a cylindrical fluidized bed

    NARCIS (Netherlands)

    Buist, K.A.; Jayaprakash, P.; Kuipers, J.A.M.; Deen, N.G.; Padding, J.T.

    2017-01-01

    In granular flow operations, often particles are nonspherical. This has inspired a vast amount of research in understanding the behavior of these particles. Various models are being developed to study the hydrodynamics involving nonspherical particles. Experiments however are often limited to obtain

  20. Controlled electrosprayed formation of non-spherical microparticles

    Science.gov (United States)

    Jeyhani, Morteza; Mak, Sze Yi; Sammut, Stephen; Shum, Ho Cheung; Hwang, Dae Kun; Tsai, Scott S. H.

    2017-11-01

    Fabrication of biocompatible microparticles, such as alginate particles, with the possibility of controlling the particles' morphology in a high-throughput manner, is essential for pharmaceutical and cosmetic industries. Even though the shape of alginate particles has been shown to be an important parameter in controlling drug delivery, there are very limited manufacturing methods to produce non-spherical alginate microparticles in a high-throughput fashion. Here, we present a system that generates non-spherical biocompatible alginate microparticles with a tunable size and shape, and at high-throughput, using an electrospray technique. Alginate solution, which is a highly biocompatible material, is flown through a needle using a constant flow rate syringe pump. The alginate phase is connected to a high-voltage power supply to charge it positively. There is a metallic ring underneath the needle that is charged negatively. The applied voltage creates an electric field that forces the dispensing droplets to pass through the metallic ring toward the collection bath. During this migration, droplets break up to smaller droplets to dissipate their energy. When the droplets reach the calcium chloride bath, polymerization happens and solidifies the droplets. We study the effects of changing the distance from the needle to the bath, and the concentration of calcium chloride in the bath, to control the size and the shape of the resulting microparticles.

  1. Angular tuning of the magnetic birefringence in rippled cobalt films

    Energy Technology Data Exchange (ETDEWEB)

    Arranz, Miguel A., E-mail: MiguelAngel.Arranz@uclm.es [Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo J. Cela 10, 13071 Ciudad Real (Spain); Colino, José M. [Instituto de Nanociencia, Nanotecnología y Materiales Moleculares, Universidad de Castilla-La Mancha, Campus de la Fábrica de Armas, 45071 Toledo (Spain)

    2015-06-22

    We report the measurement of magnetically induced birefringence in rippled Co films. For this purpose, the magneto-optical properties of ion beam eroded ferromagnetic films were studied using Kerr magnetometry and magnetic birefringence in the transmitted light intensity. Upon sufficient ion sculpting, these ripple surface nanostructures developed a defined uniaxial anisotropy in the in-plane magnetization, finely tuning the magnetic birefringence effect. We have studied its dependence on the relative orientation between the ripple direction and the magnetic field, and found this effect to be dramatically correlated with the capability to neatly distinguish the mechanisms for the in-plane magnetization reversal, i.e., rotation and nucleation. This double refraction corresponds univocally to the two magnetization axes, parallel and perpendicular to the ripples direction. We have also observed that tuned birefringence in stack assemblies of rippled Co films, which enables us to technically manipulate the number and direction of refraction axes.

  2. Birefringent Microlens Array for Ultra High Resolution HMDs, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will be used to analyze, design, model, and test a birefringent microlens array for use in a new type of...

  3. Angular tuning of the magnetic birefringence in rippled cobalt films

    International Nuclear Information System (INIS)

    Arranz, Miguel A.; Colino, José M.

    2015-01-01

    We report the measurement of magnetically induced birefringence in rippled Co films. For this purpose, the magneto-optical properties of ion beam eroded ferromagnetic films were studied using Kerr magnetometry and magnetic birefringence in the transmitted light intensity. Upon sufficient ion sculpting, these ripple surface nanostructures developed a defined uniaxial anisotropy in the in-plane magnetization, finely tuning the magnetic birefringence effect. We have studied its dependence on the relative orientation between the ripple direction and the magnetic field, and found this effect to be dramatically correlated with the capability to neatly distinguish the mechanisms for the in-plane magnetization reversal, i.e., rotation and nucleation. This double refraction corresponds univocally to the two magnetization axes, parallel and perpendicular to the ripples direction. We have also observed that tuned birefringence in stack assemblies of rippled Co films, which enables us to technically manipulate the number and direction of refraction axes

  4. Cosmological birefringence constraints from CMB and astrophysical polarization data

    Energy Technology Data Exchange (ETDEWEB)

    Galaverni, M. [Studio Teologico Interdiocesano, V.le Timavo 93, Reggio Emilia, 42121 Italy (Italy); Gubitosi, G. [Dipartimento di Fisica and sez. Roma1 INFN, Università di Roma ' La Sapienza' , P.le A. Moro 2, Rome, 00185 Italy (Italy); Paci, F. [SISSA, Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, Trieste, 34136 Italy (Italy); Finelli, F., E-mail: matteo.galaverni@gmail.com, E-mail: giulia.gubitosi@imperial.ac.uk, E-mail: fpaci@sissa.it, E-mail: finelli@iasfbo.inaf.it [INAF-IASF Bologna, via Gobetti 101, Bologna, I-40129 Italy (Italy)

    2015-08-01

    Cosmological birefringence is a rotation of the polarization plane of photons coming from sources of astrophysical and cosmological origin. The rotation can also depend on the energy of the photons and not only on the distance of the source and on the cosmological evolution of the underlying theoretical model. In this work, we constrain few selected models for cosmological birefringence, combining CMB and astrophysical data at radio, optical, X and γ wavelengths, taking into account the specific energy and distance dependences.

  5. Microdroplet-etched highly birefringent low-loss fiber tapers.

    Science.gov (United States)

    Mikkelsen, Jared C; Poon, Joyce K S

    2012-07-01

    We use hydrofluoric acid microdroplets to directly etch highly birefringent biconical fiber tapers from standard single-mode fibers. The fiber tapers have micrometer-sized cross sections, which are controlled by the etching condition. The characteristic teardrop cross section leads to a high group birefringence of B(G)≈0.017 and insertion losses <0.7 dB over waist lengths of about 2.1 mm.

  6. Sperm head's birefringence: a new criterion for sperm selection.

    Science.gov (United States)

    Gianaroli, Luca; Magli, M Cristina; Collodel, Giulia; Moretti, Elena; Ferraretti, Anna P; Baccetti, Baccio

    2008-07-01

    To investigate the characteristics of birefringence in human sperm heads and apply polarization microscopy for sperm selection at intracytoplasmic sperm injection (ICSI). Prospective randomized study. Reproductive Medicine Unit, Società Italiana Studi Medicina della Riproduzione, Bologna, Italy. A total of 112 male patients had birefringent sperm selected for ICSI (study group). The clinical outcome was compared with that obtained in 119 couples who underwent a conventional ICSI cycle (control group). The proportion of birefringent spermatozoa was evaluated before and after treatment in relation to the sperm sample quality. Embryo development and clinical outcome in the study group were compared with those in the controls. Proportion of birefringent sperm heads, rates of fertilization, cleavage, pregnancy, implantation, and ongoing implantation. The proportion of birefringent spermatozoa was significantly higher in normospermic samples when compared with oligoasthenoteratospermic samples with no progressive motility and testicular sperm extraction samples. Although fertilization and cleavage rates did not differ between the study and control groups, in the most severe male factor condition (oligoasthenoteratospermic with no progressive motility and testicular sperm extraction), the rates of clinical pregnancy, ongoing pregnancy, and implantation were significantly higher in the study group versus the controls. The analysis of birefringence in the sperm head could represent both a diagnostic tool and a novel method for sperm selection.

  7. Precise and versatile formula for birefringent filters

    Science.gov (United States)

    Shao, Zhongxing

    1996-07-01

    In an investigation of extraordinary-(E-) ray behavior and the index of refraction for E waves in a uniaxial crystal, a precise and versatile formula for birefringent filters, based on the exact construction of the optical path difference, is set up with neither the approximation Delta n = no - ne less than or equals no (or n e), nor the ambiguity sin( theta )/sin(rw) = ne. The exact construction gives the correct variation of the position and the dimension in each path, yielding the path difference while the filter is tuning. The formula is applicable not only to a filter with its optical axis parallel to the entrance surface (FAPS) but also to a filter with its axis inclined to the surface (FAIS). Also, the formula indicates that a FAIS allows laser wavelengths to be tuned over a wider range than does a FAPS. The origin of the wider range is interpreted to be the greater variation in the index for the FAIS while the filter is tuning. With the help of the formula we design a FAIS for tuning a cw 42.25.Lc.

  8. Shock waves from non-spherically collapsing cavitation bubbles

    Science.gov (United States)

    Supponen, Outi; Obreschkow, Danail; Farhat, Mohamed

    2017-11-01

    Combining simultaneous high-speed imaging and hydrophone measurements, we uncover details of the multiple shock wave emission from laser-induced cavitation bubbles collapsing in a non-spherical way. For strongly deformed bubbles collapsing near a free surface, we identify the distinct shock waves caused by the jet impact onto the opposite bubble wall and by the individual collapses of the remaining bubble segments. The energy carried by each of these shocks depends on the level of bubble deformation, quantified by the anisotropy parameter ζ, the dimensionless equivalent of the Kelvin impulse. For jetting bubbles, at ζ water hammer as ph = 0.45 (ρc2 Δp) 1 / 2ζ-1 .

  9. Non-spherical gold nanoparticles trapped in optical tweezers: Shape matters

    Czech Academy of Sciences Publication Activity Database

    Brzobohatý, Oto; Šiler, Martin; Trojek, Jan; Chvátal, Lukáš; Karásek, Vítězslav; Zemánek, Pavel

    2015-01-01

    Roč. 23, č. 7 (2015), s. 8179-8189 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GA14-16195S; GA TA ČR TE01020233; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : discrete-dipole approximation * anisotropic particles * plasmon-resonance * gaussian beams * microparticles * spectroscopy Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.148, year: 2015

  10. MISR Dark Water aerosol retrievals: operational algorithm sensitivity to particle non-sphericity

    Directory of Open Access Journals (Sweden)

    O. V. Kalashnikova

    2013-08-01

    Full Text Available The aim of this study is to theoretically investigate the sensitivity of the Multi-angle Imaging SpectroRadiometer (MISR operational (version 22 Dark Water retrieval algorithm to aerosol non-sphericity over the global oceans under actual observing conditions, accounting for current algorithm assumptions. Non-spherical (dust aerosol models, which were introduced in version 16 of the MISR aerosol product, improved the quality and coverage of retrievals in dusty regions. Due to the sensitivity of the retrieval to the presence of non-spherical aerosols, the MISR aerosol product has been successfully used to track the location and evolution of mineral dust plumes from the Sahara across the Atlantic, for example. However, the MISR global non-spherical aerosol optical depth (AOD fraction product has been found to have several climatological artifacts superimposed on valid detections of mineral dust, including high non-spherical fraction in the Southern Ocean and seasonally variable bands of high non-sphericity. In this paper we introduce a formal approach to examine the ability of the operational MISR Dark Water algorithm to distinguish among various spherical and non-spherical particles as a function of the variable MISR viewing geometry. We demonstrate the following under the criteria currently implemented: (1 Dark Water retrieval sensitivity to particle non-sphericity decreases for AOD below about 0.1 primarily due to an unnecessarily large lower bound imposed on the uncertainty in MISR observations at low light levels, and improves when this lower bound is removed; (2 Dark Water retrievals are able to distinguish between the spherical and non-spherical particles currently used for all MISR viewing geometries when the AOD exceeds 0.1; (3 the sensitivity of the MISR retrievals to aerosol non-sphericity varies in a complex way that depends on the sampling of the scattering phase function and the contribution from multiple scattering; and (4 non-sphericity

  11. Birefringence of single and bundled microtubules.

    Science.gov (United States)

    Oldenbourg, R; Salmon, E D; Tran, P T

    1998-01-01

    We have measured the birefringence of microtubules (MTs) and of MT-based macromolecular assemblies in vitro and in living cells by using the new Pol-Scope. A single microtubule in aqueous suspension and imaged with a numerical aperture of 1.4 had a peak retardance of 0.07 nm. The peak retardance of a small bundle increased linearly with the number of MTs in the bundle. Axonemes (prepared from sea urchin sperm) had a peak retardance 20 times higher than that of single MTs, in accordance with the nine doublets and two singlets arrangement of parallel MTs in the axoneme. Measured filament retardance decreased when the filament was defocused or the numerical aperture of the imaging system was decreased. However, the retardance "area," which we defined as the image retardance integrated along a line perpendicular to the filament axis, proved to be independent of focus and of numerical aperture. These results are in good agreement with a theory that we developed for measuring retardances with imaging optics. Our theoretical concept is based on Wiener's theory of mixed dielectrics, which is well established for nonimaging applications. We extend its use to imaging systems by considering the coherence region defined by the optical set-up. Light scattered from within that region interferes coherently in the image point. The presence of a filament in the coherence region leads to a polarization dependent scattering cross section and to a finite retardance measured in the image point. Similar to resolution measurements, the linear dimension of the coherence region for retardance measurements is on the order lambda/(2 NA), where lambda is the wavelength of light and NA is the numerical aperture of the illumination and imaging lenses.

  12. Birefringence in ordered (Al)GaInP

    International Nuclear Information System (INIS)

    Wirth, R.; Moritz, A.; Geng, C.; Scholz, F.; Hangleiter, A.

    1997-01-01

    We report on a way to examine the birefringence introduced by chemical ordering in (Al)GaInP using waveguide structures. We find that ordered (Al)GaInP is positively birefringent far below the band gap, while approaching the band gap it becomes negatively birefringent. The dispersion of the measured birefringence is compared with calculations that take into account the strongly anisotropic absorption at the band gap due to the splitting of the valence bands. We will show how the polarization state of light traveling along the [011] direction in chemically ordered (Al)GaInP waveguides is affected by the reduced crystal symmetry introduced by CuPt B -type ordering. Birefringence leads to a conversion of transverse electric (TE) and transverse magnetic (TM) polarized light within 60 μm. This can be understood due to new modes in the waveguide, the open-quotes supermodes,close quotes with an orientation tilted with respect to the TE/TM orientation. In the [01 bar 1] direction, the common TE/TM modes stay unchanged. With a simple theory of mode coupling, it is possible to understand the observed polarization behavior. A transfer-matrix method for anisotropic planar waveguides is used to achieve a more detailed analysis. Consequences and possibilities for applications are considered. copyright 1997 The American Physical Society

  13. Highly Nonlinear and Birefringent Spiral Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    S. Revathi

    2014-01-01

    Full Text Available We propose and design a spiral photonic crystal fiber with elliptical air holes for achieving high birefringence, large nonlinearity, and negative dispersion. The structure is designed using chalcogenide glass (As2S3 for different ellipticity ratios of air holes in the cladding and the effect on various properties is observed. The proposed structure has birefringence of the order 10−2, nonlinearity of 26739.42 W−1 m−1, and dispersion of −1136.69 at 0.85 μm. An accurate numerical approach based on finite element method is used for the design and simulation of the structure. Due to high birefringence and negative dispersion, the proposed structure can be used for polarization control and dispersion compensation, respectively.

  14. Ultraviolet-induced birefringence in hydrogen-loaded optical fiber

    DEFF Research Database (Denmark)

    Canning, John; Deyerl, Hans-Jürgen; Sørensen, Henrik Rokkjær

    2005-01-01

    for the role of hydrogen and deuterium in the UV-induced process. Previous arguments for the origins are systematically ruled out by reviewing existing literature. We note that the birefringence is made up of at least two components with different thermal stabilities, one consistent simply with molecular...... hydrogen being present in the system. Overall the birefringence, by deduction, is associated with anisotropy in hydrogen reactions within the fiber. As a result they lead, through known mechanisms of dilation in glass, to anisotropic stress relaxation that can be annealed out, with or without hydrogen...

  15. Cavity enhanced interference of orthogonal modes in a birefringent medium

    Science.gov (United States)

    Kolluru, Kiran; Saha, Sudipta; Gupta, S. Dutta

    2018-03-01

    Interference of orthogonal modes in a birefringent crystal mediated by a rotator is known to lead to interesting physical effects (Solli et al., 2003). In this paper we show that additional feedback offered by a Fabry-Perot cavity (containing the birefringent crystal and the rotator) can lead to a novel strong interaction regime. Usual signatures of the strong interaction regime like the normal mode splitting and avoided crossings, sensitive to the rotator orientation, are reported. A high finesse cavity is shown to offer an optical setup for measuring small angles. The results are based on direct calculations of the cavity transmissions along with an analysis of its dispersion relation.

  16. The PVLAS experiment for measuring the magnetic birefringence of vacuum

    International Nuclear Information System (INIS)

    Zavattini, G.; Gastaldi, U.; Messineo, G.; Piemontese, L.; Della Valle, F.; Milotti, E.; Pengo, R.; Ruoso, G.

    2013-01-01

    We describe the principle and status of the PVLAS experiment being prepared at the Department of Physics and INFN section in Ferrara, Italy. The goal of the experiment is to measure the magnetic birefringence of vacuum. This effect is directly connected to the vacuum QED structure and can be detected by measuring the ellipticity acquired by a linearly polarized laser beam traversing a strong magnetic field. Vacuum magnetic birefringence is predicted by the Euler- Heisenberg effective Lagrangian. The experimental method is also sensitive to new physics and could place new laboratory limits to hypothetical particles coupling to two photons, such as axion like particles, or millicharged particles.

  17. The Study of Birefringent Homogenous Medium with Geometric Phase

    International Nuclear Information System (INIS)

    Banerjee, Dipti

    2010-12-01

    The property of linear and circular birefringence at each point of the optical medium has been evaluated here from differential matrix N using the Jones calculus. This matrix lies on the OAM sphere for l = 1 orbital angular momentum. The geometric phase is developed by twisting the medium uniformly about the direction of propagation of the light ray. The circular birefringence of the medium, is visualized through the solid angle and the angular twist per unit thickness of the medium, k, that is equivalent to the topological charge of the optical element. (author)

  18. Effect of weak nonsphericity on linear and nonlinear optical properties of small particle composites

    International Nuclear Information System (INIS)

    Goncharenko, A.V.; Popelnukh, V.V.; Venger, E.F.

    2002-01-01

    A small particle composite in which the inclusions are slightly nonspherical and distributed in shape is considered. Within the framework of the mean-field approximation, the functions of linear and nonlinear optical responses are calculated in terms of a nonsphericity parameter specifying the width of the distribution function in shape. To estimate the effect of weak nonsphericity on the functions, their second derivatives with respect to the nonsphericity parameter are computed. The derivatives are shown to be complexly structured surfaces in the coordinates (Re(ε i /ε m ), Im(ε i /ε m )), where ε i and ε m are the inclusion and matrix permittivity, respectively. Based on the results obtained, applicability area of the classical Maxwell Garnett theory is discussed. The main conclusion is that weak nonsphericity is significant only in the close vicinity of a dipole resonance of a single ball made of inclusion material. At the same time, the role of nonsphericity increases with decreasing the imaginary part of inclusion permittivity. (author)

  19. Importance of aerosol non-sphericity in estimating aerosol radiative forcing in Indo-Gangetic Basin.

    Science.gov (United States)

    Srivastava, Parul; Dey, Sagnik; Srivastava, Atul Kumar; Singh, Sachchidanand; Mishra, S K; Tiwari, Suresh

    2017-12-01

    Aerosols are usually presumed spherical in shape while estimating the direct radiative forcing (DRF) using observations or in the models. In the Indo-Gangetic Basin (IGB), a regional aerosol hotspot where dust is a major aerosol species and has been observed to be non-spherical in shape, it is important to test the validity of this assumption. We address this issue using measured chemical composition at megacity Delhi, a representative site of the western IGB. Based on the observation, we choose three non-spherical shapes - spheroid, cylinder and chebyshev, and compute their optical properties. Non-spherical dust enhances aerosol extinction coefficient (β ext ) and single scattering albedo (SSA) at visible wavelengths by >0.05km -1 and >0.04 respectively, while it decreases asymmetry parameter (g) by ~0.1. Accounting non-sphericity leads top-of-the-atmosphere (TOA) dust DRF to more cooling due to enhanced backscattering and increases surface dimming due to enhanced β ext . Outgoing shortwave flux at TOA increases by up to 3.3% for composite aerosols with non-spherical dust externally mixed with other spherical species. Our results show that while non-sphericity needs to be accounted for, choice of shape may not be important in estimating aerosol DRF in the IGB. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Mirror Birefringence in a Fabry-Perot Cavity and the Detection of Vacuum Birefringence in a Magnetic Field

    Science.gov (United States)

    Chui, T. C. P.; Shao, M.; Redding, D.; Gursel, Y.; Boden, A.

    1995-01-01

    We discuss the effect of mirror birefringence in two optical schemes designed to detect the quantum-electrodynamics (QED) predictions of vacuum birefringence under the influence of a strong magnetic field, B. Both schemes make use of a high finesse Fabry-Perot cavity (F-P) to increase the average path length of the light in the magnetic field. The first scheme, which we called the frequency scheme, is based on measurement of the beat frequency of two orthogonal polarized laser beams in the cavity. We show that mirror birefringence contributes to the detection uncertainties in first order, resulting in a high susceptibility to small thermal disturbances. We estimate that an unreasonably high thermal stability of 10-9 K is required to resolve the effect to 0.1%. In the second scheme, which we called the polarization rotation scheme, laser polarized at 45 relative to the B field is injected into the cavity.

  1. Cancellation of birefringence in DBR laser through principal axis offset by a rotation of 90°

    Science.gov (United States)

    Zaini, M. K. A.; Lai, M. H.; Islam, M. R.; Lim, K. S.; Ahmad, H.

    2018-04-01

    The cancellation of birefringence in the distributed Bragg reflector based on 90° rotation offset method is demonstrated. It is found that the birefringence, which causes the peak bifurcation has been eliminated and a single peak is produced at each resonance in the output spectrum. This modification is an economic solution for eliminating the birefringence of the optical fibre devices.

  2. Packing Nonspherical Particles: All Shapes Are Not Created Equal

    Science.gov (United States)

    Torquato, Salvatore

    2012-02-01

    Over the past decade there has been increasing interest in the effects of particle shape on the characteristics of dense particle packings, since deviations from sphericity can lead to more realistic models of granular media, nanostructured materials, and tissue architecture. It is clear the that the broken rotational symmetry of a nonspherical particle is a crucial aspect in determining its resulting packing characteristics, but given the infinite variety of possible shapes (ellipsoids, superballs, regular and irregular polyhedra, etc.) it is desirable to formulate packing organizing principles based the particle shape. Such principles are beginning to be elucidated; see Refs. 1 and 2 and references therein. Depending upon whether the particle has central symmetry, inequivalent principle axes, and smooth or flat surfaces, we can describe the nature of its densest packing (which is typically periodic) as well as its disordered jammed states (which may or may not be isostatic). Changing the shape of a particle can dramatically alter its packing attributes. This tunability capability via particle shape could be used to tailor many-particle systems (e.g., colloids and granular media) to have designed crystal, liquid and glassy states. [4pt] [1] S. Torquato and F. H. Stillinger, ``Jammed Hard-Particle Packings: From Kepler to Bernal and Beyond," Rev. Modern Phys. 82, 2633 (2010). [0pt] [2] Y. Jiao and S. Torquato, Communication: ``A Packing of Truncated Tetrahedra That Nearly Fills All of Space and its Melting Properties," J. Chem. Phys. 135, 151101 (2011).

  3. Heat transfer rate within non-spherical thick grains

    Directory of Open Access Journals (Sweden)

    Huchet Florian

    2017-01-01

    Full Text Available The prediction of the internal heat conduction into non-spherical thick grains constitutes a significant issue for physical modeling of a large variety of application involving convective exchanges between fluid and grains. In that context, the present paper deals with heat rate measurements of various sizes of particles, the thermal sensors being located at the interface fluid/grain and into the granular materials. Their shape is designed as cuboid in order to control the surface exchanges. In enclosed coneshaped apparatus, a sharp temperature gradient is ensured from a hot source releasing the air stream temperature equal to about 400°C. Two orientations of grain related to the air stream are considered: diagonally and straight arrangements. The thermal diffusivity of the grains and the Biot numbers are estimated from an analytical solution established for slab. The thermal kinetics evolution is correlated to the sample granular mass and its orientation dependency is demonstrated. Consequently, a generalized scaling law is proposed which is funded from the effective area of the heat transfer at the grain-scale, the dimensionless time being defined from the calculated diffusional coefficients.

  4. Heat transfer rate within non-spherical thick grains

    Science.gov (United States)

    Huchet, Florian; Richard, Patrick; Joniot, Jules; Le Guen, Laurédan

    2017-06-01

    The prediction of the internal heat conduction into non-spherical thick grains constitutes a significant issue for physical modeling of a large variety of application involving convective exchanges between fluid and grains. In that context, the present paper deals with heat rate measurements of various sizes of particles, the thermal sensors being located at the interface fluid/grain and into the granular materials. Their shape is designed as cuboid in order to control the surface exchanges. In enclosed coneshaped apparatus, a sharp temperature gradient is ensured from a hot source releasing the air stream temperature equal to about 400°C. Two orientations of grain related to the air stream are considered: diagonally and straight arrangements. The thermal diffusivity of the grains and the Biot numbers are estimated from an analytical solution established for slab. The thermal kinetics evolution is correlated to the sample granular mass and its orientation dependency is demonstrated. Consequently, a generalized scaling law is proposed which is funded from the effective area of the heat transfer at the grain-scale, the dimensionless time being defined from the calculated diffusional coefficients.

  5. Equations of state of nonspherical fluids by spherical intermolecular potentials

    International Nuclear Information System (INIS)

    Bastea, S; Ree, F H

    1999-01-01

    The equilibrium properties of anisotropic molecular fluids can be in principle calculated in a statistical mechanics framework, but the theory is generally too cumbersome for many practical applications. Fortunately, at high densities and temperatures the anisotropy can be averaged-out by means of a density and temperature independent potential (the median) that produces reliable thermodynamics[1,2]. The proposal of Shaw and Johnson[1], which turns out to be the so-called median potential[2], is very successful in predicting the thermodynamics of simple fluids such as N(sub 2) and CO(sub 2) at reasonable high pressures and temperatures[3]. Lebowitz and Percus[2] pointed out some time ago that the success of this approximation could perhaps be understood in terms of a simple theory that treats the asphericity as a perturbation. The median appears to be the best choice for hard nonspherical potential[4], which may explain its success for fluids at high densities, where the hard core contribution is known to be dominant

  6. Steady three-fluid coronal expansion for nonspherical geometries

    International Nuclear Information System (INIS)

    Joselyn, J.; Holzer, T.E.

    1978-01-01

    A steady three-fluid model of the solar coronal expansionk in which 4 He ++ ions (alphas) are treated as a nonminor species, is developed for nonspherically symmetric flow geometries of the general sort thought to be characteristic of coronal holes. It is found that the very high mass fluxes in the low corona, which are associated with rapidly diverging flow geometries, lead to a locally enhanced frictional coupling between protons and alphas and consequently to a significant reduction of the He/H abundance ratio in the lower corona from that normally predicted by multifluid models. In the models considered, the frictional drag on the protons by the alphas (a process neglected in most studies) is found to play an important role near the sun. Heavy ions, other than alphas, are treated as minor species and are seen to exhibit varying responses to the rapidly diverging flow geometries, depending on the ion mass and charge. As for the protons, the frictional effect of the alphas on the heavier ions is found to be significant in the models considered

  7. Analysis of Indexed-Guided Highly Birefringent Photonic Crystal ...

    African Journals Online (AJOL)

    In this paper, a comparative study of three geometries of highly birefringent photonic crystal fibers (HB PCF) is presented. The proposed geometries are: V type PCF, Pseudo-Panda PCF and selectively liquid-filled PCF. Based on the famous Finite Difference Time Domain (FDTD) method with the perfectly matched layer ...

  8. Polarization modulational instability in a birefringent optical fiber ...

    Indian Academy of Sciences (India)

    effects on PMI gain spectra of a linearly polarized intense pump wave which experiences periodic nonlinear polarization rotation in a birefringent optical fiber in both the anomalous and normal dispersion regimes. The paper is arranged as follows: In Ü2, we briefly discuss the basic equation. In Ü3, using Floquet theorem ...

  9. Ultrasonic trap for light scattering measurement

    Science.gov (United States)

    Barton, Petr; Pavlu, Jiri

    2017-04-01

    Light scattering is complex phenomenon occurring widely in space environments, including the dense dusty clouds, nebulas or even the upper atmosphere of the Earth. However, when the size of the dust (or of other scattering center) is close to the incident light wavelength, theoretical determination is difficult. In such case, Mie theory is to be used but there is a lack of the material constants for most space-related materials. For experimental measurement of light scattering, we designed unique apparatus, based on ultrasonic trap. Using acoustic levitation we are able to capture the dust grain in midair, irradiate it with laser, and observe scattering directly with goniometer-mounted photodiode. Advantage of this approach is ability to measure directly in the air (thus, no need for the carrier medium) and possibility to study non-spherical particles. Since the trap development is nearly finished and initial experiments are carried out, the paper presents first tests on water droplets.

  10. Non-spherical particle formation induced by repulsive hydration forces during spray drying

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Yong Jae; Lee, Jin-Woo; Chang, Hankwon; Jang, Hee-Dong, E-mail: hdjang@kigam.re.kr; Cho, Kuk, E-mail: kukcho@pusan.ac.kr [Korea Institute of Geoscience and Mineral Resources (Korea, Republic of)

    2013-09-15

    Non-spherical particles were produced during a spray-drying process, but the exact mechanism of their formation was unknown. The non-spherical particles form when the strength of the colloidal droplets is exceeded by external stress stemming from drag in the velocity gradient. Here, we show that repulsive hydration forces reduce the mechanical strength of the droplets; this is critical to the formation of non-spherical particles. Toroidal or ellipsoidal particles were prepared from low-concentration hydrophilic SiO{sub 2}, TiO{sub 2}, and CuO colloidal solutions, but not from hydrophobic ZnO colloidal solutions. The surface properties of the solid particulates are crucial for the morphology of particles formed during spray drying.

  11. Non-spherical particle formation induced by repulsive hydration forces during spray drying

    International Nuclear Information System (INIS)

    Suh, Yong Jae; Lee, Jin-Woo; Chang, Hankwon; Jang, Hee-Dong; Cho, Kuk

    2013-01-01

    Non-spherical particles were produced during a spray-drying process, but the exact mechanism of their formation was unknown. The non-spherical particles form when the strength of the colloidal droplets is exceeded by external stress stemming from drag in the velocity gradient. Here, we show that repulsive hydration forces reduce the mechanical strength of the droplets; this is critical to the formation of non-spherical particles. Toroidal or ellipsoidal particles were prepared from low-concentration hydrophilic SiO 2 , TiO 2 , and CuO colloidal solutions, but not from hydrophobic ZnO colloidal solutions. The surface properties of the solid particulates are crucial for the morphology of particles formed during spray drying

  12. Constraints on cosmological birefringence energy dependence from CMB polarization data

    International Nuclear Information System (INIS)

    Gubitosi, G.; Paci, F.

    2013-01-01

    We study the possibility of constraining the energy dependence of cosmological birefringence by using CMB polarization data. We consider four possible behaviors, characteristic of different theoretical scenarios: energy-independent birefringence motivated by Chern-Simons interactions of the electromagnetic field, linear energy dependence motivated by a 'Weyl' interaction of the electromagnetic field, quadratic energy dependence, motivated by quantum gravity modifications of low-energy electrodynamics, and inverse quadratic dependence, motivated by Faraday rotation generated by primordial magnetic fields. We constrain the parameters associated to each kind of dependence and use our results to give constraints on the models mentioned. We forecast the sensitivity that Planck data will be able to achieve in this respect

  13. Towards a direct measurement of vacuum magnetic birefringence: PVLAS achievements

    Science.gov (United States)

    Della Valle, F.; Di Domenico, G.; Gastaldi, U.; Milotti, E.; Pengo, R.; Ruoso, G.; Zavattini, G.

    2010-11-01

    Nonlinear effects in vacuum have been predicted but never observed yet directly. The PVLAS collaboration has long been working on an apparatus aimed at detecting such effects by measuring vacuum magnetic birefringence. Unfortunately the sensitivity has been affected by unaccounted noise and systematics since the beginning. A new small prototype ellipsometer has been designed and characterized at the Department of Physics of the University of Ferrara, Italy entirely mounted on a single seismically isolated optical bench. With a finesse F = 414,000 and a cavity length L = 0.5 m we have reached the sensitivity of ψ=2ṡ101/√{Hz} given the laser power at the output of the ellipsometer of P = 24 mW. This record result, very close to the predicted limit, demonstrates the feasibility of reaching such sensitivities, and opens the way to designing a dedicated apparatus for a first detection of vacuum magnetic birefringence.

  14. Hydrostatic Pressure Sensing with High Birefringence Photonic Crystal Fibers

    Science.gov (United States)

    Fávero, Fernando C.; Quintero, Sully M. M.; Martelli, Cicero; Braga, Arthur M.B.; Silva, Vinícius V.; Carvalho, Isabel C. S.; Llerena, Roberth W. A.; Valente, Luiz C. G.

    2010-01-01

    The effect of hydrostatic pressure on the waveguiding properties of high birefringence photonic crystal fibers (HiBi PCF) is evaluated both numerically and experimentally. A fiber design presenting form birefringence induced by two enlarged holes in the innermost ring defining the fiber core is investigated. Numerical results show that modal sensitivity to the applied pressure depends on the diameters of the holes, and can be tailored by independently varying the sizes of the large or small holes. Numerical and experimental results are compared showing excellent agreement. A hydrostatic pressure sensor is proposed and demonstrated using an in-fiber modal interferometer where the two orthogonally polarized modes of a HiBi PCF generate fringes over the optical spectrum of a broad band source. From the analysis of experimental results, it is concluded that, in principle, an operating limit of 92 MPa in pressure could be achieved with 0.0003% of full scale resolution. PMID:22163435

  15. Determination of pitch rotation in a spherical birefringent microparticle

    Science.gov (United States)

    Roy, Basudev; Ramaiya, Avin; Schäffer, Erik

    2018-03-01

    Rotational motion of a three dimensional spherical microscopic object can happen either in pitch, yaw or roll fashion. Among these, the yaw motion has been conventionally studied using the intensity of scattered light from birefringent microspheres through crossed polarizers. Up until now, however, there is no way to study the pitch motion in spherical microspheres. Here, we suggest a new method to study the pitch motion of birefringent microspheres under crossed polarizers by measuring the 2-fold asymmetry in the scattered signal either using video microscopy or with optical tweezers. We show a couple of simple examples of pitch rotation determination using video microscopy for a microsphere attached with a kinesin molecule while moving along a microtubule and of a particle diffusing freely in water.

  16. Kerr ellipticity effect in a birefringent optical fiber

    International Nuclear Information System (INIS)

    Ishiekwene, G.C.; Mensah, S.Y.; Brown, C.S.

    2004-09-01

    An intensity-dependent change in the ellipticity of an input light beam leads to a characteristic shift in polarization instability. Dichroism gives rise to a self-induced ellipticity effect in the polarization state of an intense input light oriented along the fast axis of a birefringent optical fiber. The critical power at which the fiber effective beat length becomes infinite is reduced considerably in the presence of dichroism. (author)

  17. On the motion of non-spherical particles at high Reynolds number

    DEFF Research Database (Denmark)

    Mandø, Matthias; Rosendahl, Lasse

    2010-01-01

    This paper contains a critical review of available methodology for dealing with the motion of non-spherical particles at higher Reynolds numbers in the Eulerian- Lagrangian methodology for dispersed flow. First, an account of the various attempts to classify the various shapes and the efforts...... motion it is necessary to account for the non-coincidence between the center of pressure and center of gravity which is a direct consequence of the inertial pressure forces associated with particles at high Reynolds number flow. Extensions for non-spherical particles at higher Reynolds numbers are far...

  18. Friction factor for water flow through packed beds of spherical and non-spherical particles

    Directory of Open Access Journals (Sweden)

    Kaluđerović-Radoičić Tatjana

    2017-01-01

    Full Text Available The aim of this work was the experimental evaluation of different friction factor correlations for water flow through packed beds of spherical and non-spherical particles at ambient temperature. The experiments were performed by measuring the pressure drop across the bed. Packed beds made of monosized glass spherical particles of seven different diameters were used, as well as beds made of 16 fractions of quartz filtration sand obtained by sieving (polydisperse non-spherical particles. The range of bed voidages was 0.359–0.486, while the range of bed particle Reynolds numbers was from 0.3 to 286 for spherical particles and from 0.1 to 50 for non-spherical particles. The obtained results were compared using a number of available literature correlations. In order to improve the correlation results for spherical particles, a new simple equation was proposed in the form of Ergun’s equation, with modified coefficients. The new correlation had a mean absolute deviation between experimental and calculated values of pressure drop of 9.04%. For non-spherical quartz filtration sand particles the best fit was obtained using Ergun’s equation, with a mean absolute deviation of 10.36%. Surface-volume diameter (dSV necessary for correlating the data for filtration sand particles was calculated based on correlations for dV = f(dm and Ψ = f(dm. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON172022

  19. Tunable and rotatable birefringence controller based on electrical control of liquid crystal filled photonic bandgap fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    We demonstrate the first compact electrically tunable and rotatable birefringence controller based on LCPBG fibers. The birefringence can be tuned electrically to work as a quarter-wave or a half-wave plate in the wavelength range 1520nm-1600nm.......We demonstrate the first compact electrically tunable and rotatable birefringence controller based on LCPBG fibers. The birefringence can be tuned electrically to work as a quarter-wave or a half-wave plate in the wavelength range 1520nm-1600nm....

  20. Controlling material birefringence in sapphire via self-assembled, sub-wavelength defects

    Science.gov (United States)

    Singh, Astha; Sharma, Geeta; Ranjan, Neeraj; Mittholiya, Kshitij; Bhatnagar, Anuj; Singh, B. P.; Mathur, Deepak; Vasa, Parinda

    2018-02-01

    Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. Generally, this is an intrinsic optical property of a material and cannot be altered. Here, we report a novel technique—direct laser writing—that enables us to control the natural, material birefringence of sapphire over a broad range of wavelengths. The broadband form birefringence originating from self-assembled, periodic array of sub-wavelength (˜ 50-200 nm) defects created by laser writing, can enhance, suppress or maintain the material birefringence of sapphire without affecting its transparency range in visible or its surface quality.

  1. Thermo-mechanical screening tests to qualify beryllium pebble beds with non-spherical pebbles

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, Joerg, E-mail: joerg.reimann@partner.kit.edu [IKET, Karlsruhe Institute of Technology, Karlsruhe (Germany); Fretz, Benjamin [KBHF GmbH, Eggenstein-Leopoldshafen (Germany); Pupeschi, Simone [IAM, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2015-10-15

    Highlights: • In present ceramic breeder blankets, pebble-shaped beryllium is used as a neutron multiplier. • Spherical pebbles are considered as the candidate material, however, non-spherical particles are of economic interest. • Thermo-mechanical pebble bed data do merely exist for non-spherical beryllium grades. • Uniaxial compression tests (UCTs), combined with the Hot Wire Technique (HWT) were used to measure the stress–strain relations and the thermal conductivity. • A small experimental set-up had to be used and a detailed 3D modelling was of prime importance. • Compared to spherical pebble beds, non-spherical pebble beds are generally softer and mainly the thermal conductivity is lower. - Abstract: In present ceramic breeder blankets, pebble-shaped beryllium is used as a neutron multiplier. Fairly spherical pebbles are considered as a candidate material, however, non-spherical particles are of economic interest because production costs are much lower. Yet, thermo-mechanical pebble bed data do merely exist for these beryllium grades, and the blanket relevant potential of these grades cannot be judged. Screening experiments were performed with three different grades of non-spherical beryllium pebbles, produced by different companies, accompanied by experiments with the reference beryllium pebble beds. Uniaxial compression tests (UCTs), combined with the Hot Wire Technique (HWT), were performed to measure both the stress–strain relation and the thermal conductivity, k, at different stress levels. Because of the limited amounts of the non-spherical materials, the experimental set-ups were small and a detailed 3D modelling was of prime importance in order to prove that the used design was appropriate. Compared to the pebble beds consisting of spherical pebbles, non-spherical pebble beds are generally softer (smaller stress for a given strain), and, mainly as a consequence of this, for a given strain value, the thermal conductivity is lower. This

  2. Nonlinear polarization effects in a birefringent single mode optical fiber

    International Nuclear Information System (INIS)

    Ishiekwene, G.C.; Mensah, S.Y.; Brown, C.S.

    2001-04-01

    The nonlinear polarization effects in a birefringent single mode optical fiber is studied using Jacobi elliptic functions. We find that the polarization state of the propagating beam depends on the initial polarization as well as the intensity of the input light in a complicated way. The Stokes polarization parameters are either periodic or aperiodic depending on the value of the Jacobian modulus. Our calculations suggest that the effective beat length of the fiber can become infinite at a higher critical value of the input power when polarization dependent losses are considered. (author)

  3. Compensation for thermally induced birefringence in polycrystalline ceramic active elements

    International Nuclear Information System (INIS)

    Kagan, M A; Khazanov, E A

    2003-01-01

    Polycrystalline ceramics differ significantly from single crystals in that the crystallographic axes (and hence of the axes of thermally induced birefringence) are oriented randomly in each granule of the ceramic. The quaternion formalism is employed to calculate the depolarisation in the ceramics and the efficiency of its compensation. The obtained analytic expressions are in good agreement with the numerical relations. It is shown that the larger the ratio of the sample length to the granule size, the closer the properties of the ceramics to those of a single crystal with the [111] orientation (in particular, the uncompensated depolarisation is inversely proportional to this ratio). (active media)

  4. A better understanding of biomass co-firing by developing an advanced non-spherical particle tracking model

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse Aistrup; Kær, Søren Knudsen

    2004-01-01

    -area-to-volume ratio and thus experiences a totally different motion and reaction as a non-spherical particle. Therefore, an advanced non-spherical particle-tracking model is developed to calculate the motion and reaction of nonspherical biomass particles. The biomass particles are assumed as solid or hollow cylinders......-gradient force. Since the drag and lift forces are both shape factor- and orientation-dependent, coupled particle rotation equations are resolved to update particle orientation. In the reaction of biomass particles, the actual particle surface area available and the average oxygen mass flux at particle surface...

  5. Trapped antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Butler, E., E-mail: eoin.butler@cern.ch [CERN, Physics Department (Switzerland); Andresen, G. B. [Aarhus University, Department of Physics and Astronomy (Denmark); Ashkezari, M. D. [Simon Fraser University, Department of Physics (Canada); Baquero-Ruiz, M. [University of California, Department of Physics (United States); Bertsche, W. [Swansea University, Department of Physics (United Kingdom); Bowe, P. D. [Aarhus University, Department of Physics and Astronomy (Denmark); Cesar, C. L. [Universidade Federal do Rio de Janeiro, Instituto de Fisica (Brazil); Chapman, S. [University of California, Department of Physics (United States); Charlton, M.; Deller, A.; Eriksson, S. [Swansea University, Department of Physics (United Kingdom); Fajans, J. [University of California, Department of Physics (United States); Friesen, T.; Fujiwara, M. C. [University of Calgary, Department of Physics and Astronomy (Canada); Gill, D. R. [TRIUMF (Canada); Gutierrez, A. [University of British Columbia, Department of Physics and Astronomy (Canada); Hangst, J. S. [Aarhus University, Department of Physics and Astronomy (Denmark); Hardy, W. N. [University of British Columbia, Department of Physics and Astronomy (Canada); Hayden, M. E. [Simon Fraser University, Department of Physics (Canada); Humphries, A. J. [Swansea University, Department of Physics (United Kingdom); Collaboration: ALPHA Collaboration; and others

    2012-12-15

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only {approx}1 T ({approx}0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be 'born' inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 10{sup 4} times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172 ms and then released-the first instance of a purely antimatter atomic system confined for any length of time (Andresen et al., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen et al. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000 s in the apparatus (Andresen et al., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state.

  6. Extremely High-Birefringent Asymmetric Slotted-Core Photonic Crystal Fiber in THz Regime

    DEFF Research Database (Denmark)

    Islam, Raonaqul; Habib, Selim; Hasanuzzaman, G.K.M.

    2015-01-01

    We present a thorough numerical analysis of a highly birefringent slotted porous-core circular photonic crystal fiber (PCF) for terahertz (THz) wave guidance. The slot shaped air-holes break the symmetry of the porous-core which offers a very high birefringence whereas the compact geometry of the...

  7. Modeling optical behavior of birefringent biological tissues for evaluation of quantitative polarized light microscopy

    NARCIS (Netherlands)

    Turnhout, van M.C.; Kranenbarg, S.; Leeuwen, van J.L.

    2009-01-01

    Quantitative polarized light microscopy (qPLM) is a popular tool for the investigation of birefringent architectures in biological tissues. Collagen, the most abundant protein in mammals, is such a birefringent material. Interpretation of results of qPLM in terms of collagen network architecture and

  8. Relationships between birefringence and mineral content in artificial caries lesions of enamel.

    NARCIS (Netherlands)

    Theuns, H.M.; Shellis, R.P.; Groeneveld, A.; Dijk, J.W. van; Poole, D.F.

    1993-01-01

    The microradiographic mineral content and birefringence in water and Thoulet's solution were measured at selected points in sections of caries-like lesions. Birefringence was not related to mineral content in sound superficial enamel immersed in Thoulet's solution or in the lesion body immersed in

  9. A Novel Low Loss, Highly Birefringent Photonic Crystal Fiber in THz Regime

    DEFF Research Database (Denmark)

    Hasanuzzaman, G. K. M.; Rana, Sohel; Habib, Selim

    2016-01-01

    We present a new kind of dual-hole unit-based porous-core hexagonal photonic crystal fiber (H-PCF) with low loss and high birefringence in terahertz regime. The proposed fiber offers simultaneously high birefringence and low effective material loss (EML) in the frequency range of 0.5-0.85 THz wit...

  10. Correction of the phase retardation caused by intrinsic birefringence in deep UV lithography

    NARCIS (Netherlands)

    Serebriakov, A.; Bociort, F.; Braat, J.

    2005-01-01

    In the year 2001 it was reported that the birefringence induced by spatial dispersion (BISD), sometimes also called intrinsic birefringence, had been measured and calculated for fluorides CaF2 and BaF2 in the deep UV range. It was also shown that the magnitude of the BISD in these cubic crystals is

  11. Polarisation Control of DFB Fibre Laser Using UV-Induced Birefringent Phase-Shift

    DEFF Research Database (Denmark)

    Philipsen, Jacob Lundgreen; Lauridsen, Vibeke Claudia; Berendt, Martin Ole

    1998-01-01

    The polarisation properties of a distributed feedback (DFB) fibre laser are investigated experimentally. A birefringent phase-shift is induced by side illumination of the centre part of the lasing structure with ultraviolet (UV) light and it is experimentally shown that the birefringence...... of the phase-shift is the dominating effect controlling the polarisation properties of the laser....

  12. CMB polarization systematics, cosmological birefringence, and the gravitational waves background

    International Nuclear Information System (INIS)

    Pagano, Luca; Bernardis, Paolo de; Gubitosi, Giulia; Masi, Silvia; Melchiorri, Alessandro; Piacentini, Francesco; De Troia, Grazia; Natoli, Paolo; Polenta, Gianluca

    2009-01-01

    Cosmic microwave background experiments must achieve very accurate calibration of their polarization reference frame to avoid biasing the cosmological parameters. In particular, a wrong or inaccurate calibration might mimic the presence of a gravitational wave background, or a signal from cosmological birefringence, a phenomenon characteristic of several nonstandard, symmetry breaking theories of electrodynamics that allow for in vacuo rotation of the polarization direction of the photon. Noteworthly, several authors have claimed that the BOOMERanG 2003 (B2K) published polarized power spectra of the cosmic microwave background may hint at cosmological birefringence. Such analyses, however, do not take into account the reported calibration uncertainties of the BOOMERanG focal plane. We develop a formalism to include this effect and apply it to the BOOMERanG dataset, finding a cosmological rotation angle α=-4.3 deg. ±4.1 deg. We also investigate the expected performances of future space borne experiment, finding that an overall miscalibration larger then 1 deg. for Planck and 0.2 deg. for the Experimental Probe of Inflationary Cosmology, if not properly taken into account, will produce a bias on the constraints on the cosmological parameters and could misleadingly suggest the presence of a gravitational waves background.

  13. Scattering from Model Nonspherical Particles Theory and Applications to Environmental Physics

    CERN Document Server

    Borghese, Ferdinando; Saija, Rosalba

    2007-01-01

    The scattering of electromagnetic radiation by nonspherical particles has become an increasingly important research topic over the past 20 years. Instead of handling anisotropic particles of arbitrary shape, the authors consider the more amenable problem of aggregates of spherical particles. This is often a very satisfactory approach as the optical response of nonspherical particles depends more on their general symmetry and the quantity of refractive material than on the precise details of their shape. The book addresses a wide spectrum of applications, ranging from scattering properties of water droplets containing pollutants, atmospheric aerosols and ice crystals to the modeling of cosmic dust grains as aggregates. In this extended second edition the authors have encompassed all the new topics arising from their recent studies of cosmic dust grains. Thus many chapters were deeply revised and new chapters were added. The new material spans The description of the state of polarization of electromagnetic wave...

  14. Novel Discrete Element Method for 3D non-spherical granular particles.

    Science.gov (United States)

    Seelen, Luuk; Padding, Johan; Kuipers, Hans

    2015-11-01

    Granular materials are common in many industries and nature. The different properties from solid behavior to fluid like behavior are well known but less well understood. The main aim of our work is to develop a discrete element method (DEM) to simulate non-spherical granular particles. The non-spherical shape of particles is important, as it controls the behavior of the granular materials in many situations, such as static systems of packed particles. In such systems the packing fraction is determined by the particle shape. We developed a novel 3D discrete element method that simulates the particle-particle interactions for a wide variety of shapes. The model can simulate quadratic shapes such as spheres, ellipsoids, cylinders. More importantly, any convex polyhedron can be used as a granular particle shape. These polyhedrons are very well suited to represent non-rounded sand particles. The main difficulty of any non-spherical DEM is the determination of particle-particle overlap. Our model uses two iterative geometric algorithms to determine the overlap. The algorithms are robust and can also determine multiple contact points which can occur for these shapes. With this method we are able to study different applications such as the discharging of a hopper or silo. Another application the creation of a random close packing, to determine the solid volume fraction as a function of the particle shape.

  15. The drag and lift of different non-spherical particles from low to high Re

    Science.gov (United States)

    Sanjeevi, Sathish K. P.; Padding, Johan

    2017-11-01

    The present work investigates a simplified drag and lift model that can be used for different non-spherical particles. The flow around different non-spherical particles is studied using a multi-relaxation-time lattice Boltzmann method. We compute the mean drag coefficient CD , ϕ at different incident angles ϕ for a wide range of Reynolds numbers (Re). We show that the sine-squared drag law CD , ϕ =CD , ϕ =0° +(CD , ϕ =90° -CD , ϕ =0°) sin2 ϕ holds up to large Reynolds numbers Re = 2000 . The sine-squared dependence of CD occurs at Stokes flow (very low Re) due to linearity of the flow fields. We explore the physical origin behind the sine-squared law at high Re , and reveal that surprisingly, this does not occur due to linearity of flow fields. Instead, it occurs due to an interesting pattern of pressure distribution contributing to the drag, at higher Re , for different incident angles. Similarly, we find that the equivalent theoretical equation of lift coefficient CL can provide a decent approximation, even at high Re , for elongated particles. Such a drag and lift law valid at high Re is very much useful for Euler-Lagrangian fluidization simulations of the non-spherical particles. European Research Council (ERC) consolidator Grant scheme, Contract No. 615096 (NonSphereFlow).

  16. Investigations on birefringence effects in polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Hu, Xiaolian; Saez-Rodriguez, D.; Bang, Ole

    2014-01-01

    Step-index polymer optical fiber Bragg gratings (POFBGs) and microstructured polymer optical fiber Bragg gratings (mPOFBGs) present several attractive features, especially for sensing purposes. In comparison to FBGs written in silica fibers, they are more sensitive to temperature and pressure...... because of the larger thermo-optic coefficient and smaller Young's modulus of polymer materials. (M)POFBGs are most often photowritten in poly(methylmethacrylate) (PMMA) materials using a continuous-wave 325 nm HeCd laser. For the first time to the best of our knowledge, we study photoinduced...... birefringence effects in (m)POFBGs. To achieve this, highly reflective gratings were inscribed with the phase mask technique. They were then monitored in transmission with polarized light. For this, (m)POF sections a few cm in length containing the gratings were glued to angled silica fibers. Polarization...

  17. Experimental study on birefringence effect in high-tension bolts

    International Nuclear Information System (INIS)

    Kim, No You; Lee, Sang Soon; Jang, Kyung Young

    2005-01-01

    Bolts widely used in machine parts and assemblies are pre-loaded to prevent the parts from separating and to maintain the strength of the assemblies. Conventional technique for measurement of this axial stress applied to bolts is torque meter, but it has two disadvantages. The first one is its inherent inaccuracy. The second is that the stress cannot be determined after assembly without twisting bolts. The most promising technique for measurement of the axial stress is the acousto-elasticity. In this study, a new acousto-elasticity technique based on birefringence principle is proposed and tested to measure the axial stress in bolts which uses two longitudinal and shear waves instead of two horizontally polarized shear waves. From experimental results, the difference between the longitudinal and shear wave velocity is shown to be linearly related to the applied stress and be able to be used effectively to monitor the axial stress in bolts.

  18. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  19. Viscosity and transient electric birefringence study of clay colloidal aggregation.

    Science.gov (United States)

    Bakk, Audun; Fossum, Jon O; da Silva, Geraldo J; Adland, Hans M; Mikkelsen, Arne; Elgsaeter, Arnljot

    2002-02-01

    We study a synthetic clay suspension of laponite at different particle and NaCl concentrations by measuring stationary shear viscosity and transient electrically induced birefringence (TEB). On one hand the viscosity data are consistent with the particles being spheres and the particles being associated with large amount bound water. On the other hand the viscosity data are also consistent with the particles being asymmetric, consistent with single laponite platelets associated with a very few monolayers of water. We analyze the TEB data by employing two different models of aggregate size (effective hydrodynamic radius) distribution: (1) bidisperse model and (2) log-normal distributed model. Both models fit, in the same manner, fairly well to the experimental TEB data and they indicate that the suspension consists of polydisperse particles. The models also appear to confirm that the aggregates increase in size vs increasing ionic strength. The smallest particles at low salt concentrations seem to be monomers and oligomers.

  20. Strong optical feedback in birefringent dual frequency laser

    Institute of Scientific and Technical Information of China (English)

    Mao Wei; Zhang Shu-Lian

    2006-01-01

    Strong optical feedback in a birefringent dual frequency He-Ne laser with a high reflectivity feedback mirror has been investigated for the first time. The output characteristics of two orthogonally polarized modes are demonstrated in two different optical feedback cases: one is for both modes being fed back and the other is for only one of the modes being fed back. Strong mode competition can be observed between the two modes with strong optical feedback. And when one mode's intensity is near its maximum, the other mode is nearly extinguished. When both modes are fed back into the laser cavity, the mode competition is stronger than when only one mode is fed back. The difference in initial intensity between the two orthogonally polarized modes plays an important role in the mode competition, which has been experimentally and theoretically demonstrated.

  1. A Linear Birefringence Measurement Method for an Optical Fiber Current Sensor.

    Science.gov (United States)

    Xu, Shaoyi; Shao, Haiming; Li, Chuansheng; Xing, Fangfang; Wang, Yuqiao; Li, Wei

    2017-07-03

    In this work, a linear birefringence measurement method is proposed for an optical fiber current sensor (OFCS). First, the optical configuration of the measurement system is presented. Then, the elimination method of the effect of the azimuth angles between the sensing fiber and the two polarizers is demonstrated. Moreover, the relationship of the linear birefringence, the Faraday rotation angle and the final output is determined. On these bases, the multi-valued problem on the linear birefringence is simulated and its solution is illustrated when the linear birefringence is unknown. Finally, the experiments are conducted to prove the feasibility of the proposed method. When the numbers of turns of the sensing fiber in the OFCS are about 15, 19, 23, 27, 31, 35, and 39, the measured linear birefringence obtained by the proposed method are about 1.3577, 1.8425, 2.0983, 2.5914, 2.7891, 3.2003 and 3.5198 rad. Two typical methods provide the references for the proposed method. The proposed method is proven to be suitable for the linear birefringence measurement in the full range without the limitation that the linear birefringence must be smaller than π/2.

  2. Ripple Trap

    Science.gov (United States)

    2006-01-01

    3 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of a lava flow on a cratered plain in the Athabasca Vallis region of Mars. Remarkably, the cratered plain in this scene is essentially free of bright, windblown ripples. Conversely, the lava flow apparently acted as a trap for windblown materials, illustrated by the presence of the light-toned, wave-like texture over much of the flow. That the lava flow surface trapped windblown sand and granules better than the cratered plain indicates that the flow surface has a rougher texture at a scale too small to resolve in this image. Location near: 10.7oN, 204.5oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  3. Trapped antihydrogen

    CERN Document Server

    Butler, E; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jonsell, S; Jørgensen, L V; Kemp, S L; Kurchaninov, L; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Seif el Nasr, S; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki,Y

    2012-01-01

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ∼1 T (∼0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be ‘born’ inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been ...

  4. Large tuning of birefringence in two strip silicon waveguides via optomechanical motion.

    Science.gov (United States)

    Ma, Jing; Povinelli, Michelle L

    2009-09-28

    We present an optomechanical method to tune phase and group birefringence in parallel silicon strip waveguides. We first calculate the deformation of suspended, parallel strip waveguides due to optical forces. We optimize the frequency and polarization of the pump light to obtain a 9 nm deformation for an optical power of 20 mW. Widely tunable phase and group birefringence can be achieved by varying the pump power, with maximum values of 0.026 and 0.13, respectively. The giant phase birefringence allows linear to circular polarization conversion within 30 microm for a pump power of 67 mW. The group birefringence gives a tunable differential group delay of 6fs between orthogonal polarizations. We also evaluate the tuning performance of waveguides with different cross sections.

  5. A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields

    Energy Technology Data Exchange (ETDEWEB)

    Zavattini, G.; Ejlli, A. [Universita di Ferrara, Dipt. di Fisica e Scienze della Terra (Italy); INFN, Sezione di Ferrara (Italy); Della Valle, F. [Universita di Trieste, Dipt. di Fisica, Trieste (Italy); INFN, Sezione di Trieste, TS (Italy); Ruoso, G. [INFN, Lab. Nazionali di Legnaro (Italy)

    2016-05-15

    A novel polarisation modulation scheme for polarimeters based on Fabry-Perot cavities is presented. The application to the measurement of the magnetic birefringence of vacuum with the HERA superconducting magnets in the ALPS-II configuration is discussed. (orig.)

  6. Evaluation of advanced automatic PET segmentation methods using nonspherical thin-wall inserts

    International Nuclear Information System (INIS)

    Berthon, B.; Marshall, C.; Evans, M.; Spezi, E.

    2014-01-01

    Purpose: The use of positron emission tomography (PET) within radiotherapy treatment planning requires the availability of reliable and accurate segmentation tools. PET automatic segmentation (PET-AS) methods have been recommended for the delineation of tumors, but there is still a lack of thorough validation and cross-comparison of such methods using clinically relevant data. In particular, studies validating PET segmentation tools mainly use phantoms with thick plastic walls inserts of simple spherical geometry and have not specifically investigated the effect of the target object geometry on the delineation accuracy. Our work therefore aimed at generating clinically realistic data using nonspherical thin-wall plastic inserts, for the evaluation and comparison of a set of eight promising PET-AS approaches. Methods: Sixteen nonspherical inserts were manufactured with a plastic wall of 0.18 mm and scanned within a custom plastic phantom. These included ellipsoids and toroids derived with different volumes, as well as tubes, pear- and drop-shaped inserts with different aspect ratios. A set of six spheres of volumes ranging from 0.5 to 102 ml was used for a baseline study. A selection of eight PET-AS methods, written in house, was applied to the images obtained. The methods represented promising segmentation approaches such as adaptive iterative thresholding, region-growing, clustering and gradient-based schemes. The delineation accuracy was measured in terms of overlap with the computed tomography reference contour, using the dice similarity coefficient (DSC), and error in dimensions. Results: The delineation accuracy was lower for nonspherical inserts than for spheres of the same volume in 88% cases. Slice-by-slice gradient-based methods, showed particularly lower DSC for tori (DSC 0.76 except for tori) but showed the largest errors in the recovery of pears and drops dimensions (higher than 10% and 30% of the true length, respectively). Large errors were visible

  7. Accurate and quantitative polarization-sensitive OCT by unbiased birefringence estimator with noise-stochastic correction

    Science.gov (United States)

    Kasaragod, Deepa; Sugiyama, Satoshi; Ikuno, Yasushi; Alonso-Caneiro, David; Yamanari, Masahiro; Fukuda, Shinichi; Oshika, Tetsuro; Hong, Young-Joo; Li, En; Makita, Shuichi; Miura, Masahiro; Yasuno, Yoshiaki

    2016-03-01

    Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of OCT that contrasts the polarization properties of tissues. It has been applied to ophthalmology, cardiology, etc. Proper quantitative imaging is required for a widespread clinical utility. However, the conventional method of averaging to improve the signal to noise ratio (SNR) and the contrast of the phase retardation (or birefringence) images introduce a noise bias offset from the true value. This bias reduces the effectiveness of birefringence contrast for a quantitative study. Although coherent averaging of Jones matrix tomography has been widely utilized and has improved the image quality, the fundamental limitation of nonlinear dependency of phase retardation and birefringence to the SNR was not overcome. So the birefringence obtained by PS-OCT was still not accurate for a quantitative imaging. The nonlinear effect of SNR to phase retardation and birefringence measurement was previously formulated in detail for a Jones matrix OCT (JM-OCT) [1]. Based on this, we had developed a maximum a-posteriori (MAP) estimator and quantitative birefringence imaging was demonstrated [2]. However, this first version of estimator had a theoretical shortcoming. It did not take into account the stochastic nature of SNR of OCT signal. In this paper, we present an improved version of the MAP estimator which takes into account the stochastic property of SNR. This estimator uses a probability distribution function (PDF) of true local retardation, which is proportional to birefringence, under a specific set of measurements of the birefringence and SNR. The PDF was pre-computed by a Monte-Carlo (MC) simulation based on the mathematical model of JM-OCT before the measurement. A comparison between this new MAP estimator, our previous MAP estimator [2], and the standard mean estimator is presented. The comparisons are performed both by numerical simulation and in vivo measurements of anterior and

  8. Magneto-optic current sensor with Faraday mirror for linear birefringence compensation

    OpenAIRE

    Arroyo Breña, Javier; Rodriguez Horche, Paloma; Martín Minguez, Alfredo

    2012-01-01

    Fiber optic sensors have some advantages in subjects related with electrical current and magnetic field measurement. In spite of the optical fiber utilization advantages we have to take into account undesirable effects, which are present in real non-ideal optical fibers. In telecommunication and sensor application fields the presence of inherent and induced birefringence is crucial. The presence of birefringence may cause an undesirable change in the polarization state. In order to compensate...

  9. Modeling the Interaction of Mineral Dust with Solar Radiation: Spherical versus Non-spherical Particles

    Science.gov (United States)

    Hoshyaripour, A.; Vogel, B.; Vogel, H.

    2017-12-01

    Mineral dust, emitted from arid and semi-arid regions, is the most dominant atmospheric aerosol by mass. Beside detrimental effect on air quality, airborne dust also influences the atmospheric radiation by absorbing and scattering solar and terrestrial radiation. As a result, while the long-term radiative impacts of dust are important for climate, the short-term effects are significant for the photovoltaic energy production. Therefore, it is a vital requirement to accurately forecast the effects of dust on energy budget of the atmosphere and surface. To this end, a major issue is the fact that dust particles are non-spherical. Thus, the optical properties of such particles cannot be calculated precisely using the conventional methods like Mie theory that are often used in climate and numerical weather forecast models. In this study, T-Matrix method is employed, which is able to treat the non-sphericity of particles. Dust particles are assumed to be prolate spheroids with aspect ratio of 1.5 distributed in three lognormal modes. The wavelength-dependent refractive indices of dust are used in T-Matrix algorithm to calculate the extinction coefficient, single scattering albedo, asymmetry parameter and backscattering ratio at different wavelengths. These parameters are then implemented in ICON-ART model (ICOsahedral Nonhydrostatic model with Aerosols and Reactive Trace gases) to conduct a global simulation with 80 km horizontal resolution and 90 vertical levels. April 2014 is selected as the simulation period during which North African dust plumes reached central Europe and Germany. Results show that treatment of non-sphericity reduces the dust AOD in the range of 10 to 30%/. The impacts on diffuse and direct radiation at global, regional and local scales show strong dependency on the size distribution of the airborne dust. The implications for modeling and remote sensing the dust impacts on solar energy are also discussed.

  10. Differential diagnosis of periapical cyst using collagen birefringence pattern of the cyst wall

    Directory of Open Access Journals (Sweden)

    Hyo Jin Ji

    2017-05-01

    Full Text Available Objectives Periapical lesions, including periapical cyst (PC, periapical granuloma (PG, and periapical abscess (PA, are frequently affected by chemical/physical damage during root canal treatment or severe bacterial infection, and thus, the differential diagnosis of periapical lesions may be difficult due to the presence of severe inflammatory reaction. The aim of this study was to make differential diagnosis among PC, PG, and PA under polarizing microscope. Materials and Methods The collagen birefringence patterns of 319 cases of PC (n = 122, PG (n = 158, and PA (n = 39 obtained using a polarizing microscope were compared. In addition, 6 cases of periodontal fibroma (PF were used as positive controls. Results Collagen birefringence was condensed with a thick, linear band-like pattern in PC, but was short and irregularly scattered in PG, and scarce or absent in PA. PF showed intense collagen birefringence with a short, palisading pattern but no continuous band-like pattern. The linear band-like birefringence in PC was ascribed to pre-existing expansile tensile stress of the cyst wall. Conclusions In this study all PCs (n = 122 were distinguishable from PGs and PAs by their characteristic birefringence, despite the absence of lining epithelium (n = 20. Therefore, the authors suggest that the presence of linear band-like collagen birefringence of the cyst wall aids the diagnostic differentiation of PC from PG and PA.

  11. Quantification of birefringence readily measures the level of muscle damage in zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Joachim, E-mail: Joachim.Berger@Monash.edu [Australian Regenerative Medicine Institute, EMBL Australia, Monash University, Clayton (Australia); Sztal, Tamar; Currie, Peter D. [Australian Regenerative Medicine Institute, EMBL Australia, Monash University, Clayton (Australia)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer Report of an unbiased quantification of the birefringence of muscle of fish larvae. Black-Right-Pointing-Pointer Quantification method readily identifies level of overall muscle damage. Black-Right-Pointing-Pointer Compare zebrafish muscle mutants for level of phenotype severity. Black-Right-Pointing-Pointer Proposed tool to survey treatments that aim to ameliorate muscular dystrophy. -- Abstract: Muscular dystrophies are a group of genetic disorders that progressively weaken and degenerate muscle. Many zebrafish models for human muscular dystrophies have been generated and analysed, including dystrophin-deficient zebrafish mutants dmd that model Duchenne Muscular Dystrophy. Under polarised light the zebrafish muscle can be detected as a bright area in an otherwise dark background. This light effect, called birefringence, results from the diffraction of polarised light through the pseudo-crystalline array of the muscle sarcomeres. Muscle damage, as seen in zebrafish models for muscular dystrophies, can readily be detected by a reduction in the birefringence. Therefore, birefringence is a very sensitive indicator of overall muscle integrity within larval zebrafish. Unbiased documentation of the birefringence followed by densitometric measurement enables the quantification of the birefringence of zebrafish larvae. Thereby, the overall level of muscle integrity can be detected, allowing the identification and categorisation of zebrafish muscle mutants. In addition, we propose that the establish protocol can be used to analyse treatments aimed at ameliorating dystrophic zebrafish models.

  12. Quantification of birefringence readily measures the level of muscle damage in zebrafish

    International Nuclear Information System (INIS)

    Berger, Joachim; Sztal, Tamar; Currie, Peter D.

    2012-01-01

    Highlights: ► Report of an unbiased quantification of the birefringence of muscle of fish larvae. ► Quantification method readily identifies level of overall muscle damage. ► Compare zebrafish muscle mutants for level of phenotype severity. ► Proposed tool to survey treatments that aim to ameliorate muscular dystrophy. -- Abstract: Muscular dystrophies are a group of genetic disorders that progressively weaken and degenerate muscle. Many zebrafish models for human muscular dystrophies have been generated and analysed, including dystrophin-deficient zebrafish mutants dmd that model Duchenne Muscular Dystrophy. Under polarised light the zebrafish muscle can be detected as a bright area in an otherwise dark background. This light effect, called birefringence, results from the diffraction of polarised light through the pseudo-crystalline array of the muscle sarcomeres. Muscle damage, as seen in zebrafish models for muscular dystrophies, can readily be detected by a reduction in the birefringence. Therefore, birefringence is a very sensitive indicator of overall muscle integrity within larval zebrafish. Unbiased documentation of the birefringence followed by densitometric measurement enables the quantification of the birefringence of zebrafish larvae. Thereby, the overall level of muscle integrity can be detected, allowing the identification and categorisation of zebrafish muscle mutants. In addition, we propose that the establish protocol can be used to analyse treatments aimed at ameliorating dystrophic zebrafish models.

  13. Differential diagnosis of periapical cyst using collagen birefringence pattern of the cyst wall.

    Science.gov (United States)

    Ji, Hyo Jin; Park, Se-Hee; Cho, Kyung-Mo; Lee, Suk Keun; Kim, Jin Woo

    2017-05-01

    Periapical lesions, including periapical cyst (PC), periapical granuloma (PG), and periapical abscess (PA), are frequently affected by chemical/physical damage during root canal treatment or severe bacterial infection, and thus, the differential diagnosis of periapical lesions may be difficult due to the presence of severe inflammatory reaction. The aim of this study was to make differential diagnosis among PC, PG, and PA under polarizing microscope. The collagen birefringence patterns of 319 cases of PC ( n = 122), PG ( n = 158), and PA ( n = 39) obtained using a polarizing microscope were compared. In addition, 6 cases of periodontal fibroma (PF) were used as positive controls. Collagen birefringence was condensed with a thick, linear band-like pattern in PC, but was short and irregularly scattered in PG, and scarce or absent in PA. PF showed intense collagen birefringence with a short, palisading pattern but no continuous band-like pattern. The linear band-like birefringence in PC was ascribed to pre-existing expansile tensile stress of the cyst wall. In this study all PCs ( n = 122) were distinguishable from PGs and PAs by their characteristic birefringence, despite the absence of lining epithelium ( n = 20). Therefore, the authors suggest that the presence of linear band-like collagen birefringence of the cyst wall aids the diagnostic differentiation of PC from PG and PA.

  14. Preparation of non-spherical particles by shell-shield etching for near-field nanopatterning

    International Nuclear Information System (INIS)

    Ye, Jian; Liesbet, Lagae

    2014-01-01

    The shape of polymer particles plays an important role in determining their function. In this paper, we describe a simple and unconventional method called shell-shield etching (SSE) that allows us to prepare freestanding submicrometer- or micrometer-sized polymer particles with various shapes. By precisely varying the time of ultraviolet ozone treatment under the partial shielding effect of the silica shell, we controllably reshape polymer spheres into symmetry-reduced polymer peaches, mushrooms, bowls, and plates. Finite difference time domain simulations indicate that the non-spherical particles obtained from the SSE method might have potential for near-field nanopatterning applications. (papers)

  15. Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. of Texas, El Paso, TX (United States). Dept. of Mechanical Engineering

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed

  16. Generation and dynamics of quadratic birefringent spatial gap solitons

    International Nuclear Information System (INIS)

    Anghel-Vasilescu, P.; Dorignac, J.; Geniet, F.; Leon, J.; Taki, A.

    2011-01-01

    A method is proposed to generate and study the dynamics of spatial light solitons in a birefringent medium with quadratic nonlinearity. Although no analytical expression for propagating solitons has been obtained, our numerical simulations show the existence of stable localized spatial solitons in the frequency forbidden band gap of the medium. The dynamics of these objects is quite rich and manifests for instance elastic reflections, or inelastic collisions where two solitons merge and propagate as a single solitary wave. We derive the dynamics of the slowly varying envelopes of the three fields (second harmonic pump and two-component signal) and study this new system theoretically. We show that it does present a threshold for nonlinear supratransmission that can be calculated from a series expansion approach with a very high accuracy. Specific physical implications of our theoretical predictions are illustrated on LiGaTe 2 (LGT) crystals. Once irradiated by a cw laser beam of 10 μm wavelength, at an incidence beyond the extinction angle, such crystals will transmit light, in the form of spatial solitons generated in the nonlinear regime above the nonlinear supratransmission threshold.

  17. Measuring the Magnetic Birefringence of Vacuum: the Pvlas Experiment

    Science.gov (United States)

    Zavattini, G.; Gastaldi, U.; Pengo, R.; Ruoso, G.; Della Valle, F.; Milotti, E.

    2012-06-01

    We describe the principle and the status of the PVLAS experiment which is presently running at the INFN section of Ferrara, Italy, to detect the magnetic birefringence of vacuum. This is related to the QED vacuum structure and can be detected by measuring the ellipticity acquired by a linearly polarized light beam propagating through a strong magnetic field. Such an effect is predicted by the Euler-Heisenberg Lagrangian. The method is also sensitive to other hypothetical physical effects such as axion-like particles and in general to any fermion/boson millicharged particle. Here we report on the construction of our apparatus based on a high finesse (> 2·105) Fabry-Perot cavity and two 0.9 m long 2.5 T permanent dipole rotating magnets, and on the measurements performed on a scaled down test setup. With the test setup we have improved by about a factor 2 the limit on the parameter Ae describing nonlinear electrodynamic effects in vacuum: Ae < 2.9 · 10-21 T-2 @ 95% C.L.

  18. Investigation of flow regime in debris bed formation behavior with nonspherical particles

    Directory of Open Access Journals (Sweden)

    Songbai Cheng

    2018-02-01

    Full Text Available It is important to clarify the characteristics of flow regimes underlying the debris bed formation behavior that might be encountered in core disruptive accidents of sodium-cooled fast reactors. Although in our previous publications, by applying dimensional analysis technique, an empirical model, with its reasonability confirmed over a variety of parametric conditions, has been successfully developed to predict the regime transition and final bed geometry formed, so far this model is restricted to predictions of debris mixtures composed of spherical particles. Focusing on this aspect, in this study a new series of experiments using nonspherical particles have been conducted. Based on the knowledge and data obtained, an extension scheme is suggested with the purpose of extending the base model to cover the particle-shape influence. Through detailed analyses and given our current range of experimental conditions, it is found that, by coupling the base model with this scheme, respectable agreement between experiments and model predictions for the regime transition can be achieved for both spherical and nonspherical particles. Knowledge and evidence from our work might be utilized for the future improvement of design of an in-vessel core catcher as well as the development and verification of sodium-cooled fast reactor severe accident analysis codes in China.

  19. SECONDARY EMISSION FROM NON-SPHERICAL DUST GRAINS WITH ROUGH SURFACES: APPLICATION TO LUNAR DUST

    International Nuclear Information System (INIS)

    Richterová, I.; Němeček, Z.; Beránek, M.; Šafránková, J.; Pavlů, J.

    2012-01-01

    Electrons impinging on a target can release secondary electrons and/or they can be scattered out of the target. It is well established that the number of escaping electrons per primary electron depends on the target composition and dimensions, the energy, and incidence angle of the primary electrons, but there are suggestions that the target's shape and surface roughness also influence the secondary emission. We present a further modification of the model of secondary electron emission from dust grains which is applied to non-spherical grains and grains with defined surface roughness. It is shown that the non-spherical grains give rise to a larger secondary electron yield, whereas the surface roughness leads to a decrease in the yield. Moreover, these effects can be distinguished: the shape effect is prominent for high primary energies, whereas the surface roughness predominantly affects the yield at the low-energy range. The calculations use the Lunar Highlands Type NU-LHT-2M simulant as a grain material and the results are compared with previously published laboratory and in situ measurements.

  20. ASPECT RATIO DEPENDENCE OF THE FREE-FALL TIME FOR NON-SPHERICAL SYMMETRIES

    Energy Technology Data Exchange (ETDEWEB)

    Pon, Andy; Johnstone, Doug [Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, STN CSC, Victoria, BC V8W 3P6 (Canada); Toala, Jesus A. [Instituto de Astrofisica de Andalucia, CSIC, Glorieta de la Astronomia s/n, E-18008, Granada (Spain); Vazquez-Semadeni, Enrique; Gomez, Gilberto C. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Campus Morelia Apartado Postal 3-72, 58090 Morelia, Michoacan (Mexico); Heitsch, Fabian, E-mail: arpon@uvic.ca, E-mail: Douglas.Johnstone@nrc-cnrc.gc.ca, E-mail: toala@iaa.es, E-mail: e.vazquez@crya.unam.mx, E-mail: g.gomez@crya.unam.mx, E-mail: fheitsch@unc.edu [Department of Physics and Astronomy, University of North Carolina Chapel Hill, CB 3255, Phillips Hall, Chapel Hill, NC 27599 (United States)

    2012-09-10

    We investigate the collapse of non-spherical substructures, such as sheets and filaments, which are ubiquitous in molecular clouds. Such non-spherical substructures collapse homologously in their interiors but are influenced by an edge effect that causes their edges to be preferentially accelerated. We analytically compute the homologous collapse timescales of the interiors of uniform-density, self-gravitating filaments and find that the homologous collapse timescale scales linearly with the aspect ratio. The characteristic timescale for an edge-driven collapse mode in a filament, however, is shown to have a square-root dependence on the aspect ratio. For both filaments and circular sheets, we find that selective edge acceleration becomes more important with increasing aspect ratio. In general, we find that lower dimensional objects and objects with larger aspect ratios have longer collapse timescales. We show that estimates for star formation rates, based upon gas densities, can be overestimated by an order of magnitude if the geometry of a cloud is not taken into account.

  1. Real-space calculations of nonspherically averaged charge densities for substitutionally disordered alloys

    International Nuclear Information System (INIS)

    Singh, P.P.; Gonis, A.

    1993-01-01

    Based on screening transformations of muffin-tin orbitals introduced by Andersen and Jepsen [Phys. Rev. Lett. 53, 2571 (1984)], we have developed a formalism for calculating the nonspherically averaged charge densities of substitutionally disordered alloys using the Korringa-Kohn-Rostoker coherent-potential-approximation (KKR CPA) method in the atomic-sphere approximation (ASA). We have validated our method by calculating charge densities for ordered structures, where we find that our approach yields charge densities that are essentially indistinguishable from the results of full-potential methods. Calculations and comparisons are reported for Si, Al, and Li. For substitutionally disordered alloys, where full-potential methods have not been implemented so far, our approach can be used to calculate reliable nonspherically averaged charge densities from spherically symmetric one-electron potentials obtained from the KKR-ASA CPA. We report on our study of differences in charge density between ordered AlLi in the L1 0 phase and substitutionally disordered Al 0.5 Li 0.5 on a face-centered-cubic lattice

  2. Statistical multifragmentation of non-spherical expanding sources in central heavy-ion collisions

    International Nuclear Information System (INIS)

    Le Fevre, A.; Ploszajczak, M.; Toneev, V.D.

    2003-10-01

    We study the anisotropy effects measured with INDRA at GSI in central collisions of 129 Xe+ nat Sn at 50 A MeV and 197 Au+ 197 Au at 60, 80, 100 A MeV incident energy. The microcanonical multifragmentation model with non-spherical sources is used to simulate an incomplete shape relaxation of the multifragmenting system. This model is employed to interpret observed anisotropic distributions in the fragment size and mean kinetic energy. The data can be well reproduced if an expanding prolate source aligned along the beam direction is assumed. In the model, the anisotropy is the result of correlations between the charge of a fragment and its location in the freeze-out configuration, created by the mutual Coulomb interactions inside the non-spherical source. An either non-Hubblean or non-isotropic radial expansion is required to describe the fragment kinetic energies and their anisotropy. The qualitative similarity of the results for the studied reactions suggests that the concept of a longitudinally elongated freeze-out configuration is generally applicable for central collisions of heavy systems. The deformation decreases slightly with increasing beam energy. (orig.)

  3. ASPECT RATIO DEPENDENCE OF THE FREE-FALL TIME FOR NON-SPHERICAL SYMMETRIES

    International Nuclear Information System (INIS)

    Pon, Andy; Johnstone, Doug; Toalá, Jesús A.; Vázquez-Semadeni, Enrique; Gómez, Gilberto C.; Heitsch, Fabian

    2012-01-01

    We investigate the collapse of non-spherical substructures, such as sheets and filaments, which are ubiquitous in molecular clouds. Such non-spherical substructures collapse homologously in their interiors but are influenced by an edge effect that causes their edges to be preferentially accelerated. We analytically compute the homologous collapse timescales of the interiors of uniform-density, self-gravitating filaments and find that the homologous collapse timescale scales linearly with the aspect ratio. The characteristic timescale for an edge-driven collapse mode in a filament, however, is shown to have a square-root dependence on the aspect ratio. For both filaments and circular sheets, we find that selective edge acceleration becomes more important with increasing aspect ratio. In general, we find that lower dimensional objects and objects with larger aspect ratios have longer collapse timescales. We show that estimates for star formation rates, based upon gas densities, can be overestimated by an order of magnitude if the geometry of a cloud is not taken into account.

  4. Linear analysis on the growth of non-spherical perturbations in supersonic accretion flows

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Kazuya; Yamada, Shoichi, E-mail: ktakahashi@heap.phys.waseda.ac.jp [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku 169-8555 (Japan)

    2014-10-20

    We analyzed the growth of non-spherical perturbations in supersonic accretion flows. We have in mind an application to the post-bounce phase of core-collapse supernovae (CCSNe). Such non-spherical perturbations have been suggested by a series of papers by Arnett, who has numerically investigated violent convections in the outer layers of pre-collapse stars. Moreover, Couch and Ott demonstrated in their numerical simulations that such perturbations may lead to a successful supernova even for a progenitor that fails to explode without fluctuations. This study investigated the linear growth of perturbations during the infall onto a stalled shock wave. The linearized equations are solved as an initial and boundary value problem with the use of a Laplace transform. The background is a Bondi accretion flow whose parameters are chosen to mimic the 15 M {sub ☉} progenitor model by Woosley and Heger, which is supposed to be a typical progenitor of CCSNe. We found that the perturbations that are given at a large radius grow as they flow down to the shock radius; the density perturbations can be amplified by a factor of 30, for example. We analytically show that the growth rate is proportional to l, the index of the spherical harmonics. We also found that the perturbations oscillate in time with frequencies that are similar to those of the standing accretion shock instability. This may have an implication for shock revival in CCSNe, which will be investigated in our forthcoming paper in more detail.

  5. Globalisation Trapped

    Directory of Open Access Journals (Sweden)

    João Caraça

    2017-05-01

    Full Text Available The promise of making society progress through the direct applications of science was finally fulfilled in the mid-20th century. Science progressed immensely, propelled by the effects of the two world wars. The first science-based technologies saw the daylight during the 1940s and their transformative power was such that neither the military, nor subsequently the markets, allowed science to return intact to its curiosity-driven nest. Technoscience was born then and (being progressively pulled away from curiosity-driven science was able to grow enormously, erecting a formidable structure of networks of institutions that impacted decisively on the economy. It is a paradox, or maybe a trap, that the fulfillment of science’s solemn promise of ‘transforming nature’ means seeing ourselves and our Western societies entangled in crises after crises with no clear outcome in view. A redistribution of geopolitical power is under way, along with the deployment of information and communication technologies, forcing dominant structures to oscillate, as knowledge about organization and methods, marketing, design, and software begins to challenge the role of technoscience as the main vector of economic growth and wealth accumulation. What ought to be done?

  6. Shape effects on time-scale divergence at athermal jamming transition of frictionless non-spherical particles

    Science.gov (United States)

    Yuan, Ye; Jin, Weiwei; Liu, Lufeng; Li, Shuixiang

    2017-10-01

    The critical behaviors of a granular system at the jamming transition have been extensively studied from both mechanical and thermodynamic perspectives. In this work, we numerically investigate the jamming behaviors of a variety of frictionless non-spherical particles, including spherocylinder, ellipsoid, spherotetrahedron and spherocube. In particular, for a given particle shape, a series of random configurations at different fixed densities are generated and relaxed to minimize interparticle overlaps using the relaxation algorithm. We find that as the jamming point (i.e., point J) is approached, the number of iteration steps (defined as the "time-scale" for our systems) required to completely relax the interparticle overlaps exhibits a clear power-law divergence. The dependence of the detailed mathematical form of the power-law divergence on particle shapes is systematically investigated and elucidated, which suggests that the shape effects can be generally categorized as elongation and roundness. Importantly, we show the jamming transition density can be accurately determined from the analysis of time-scale divergence for different non-spherical shapes, and the obtained values agree very well with corresponding ones reported in literature. Moreover, we study the plastic behaviors of over-jammed packings of different particles under a compression-expansion procedure and find that the jamming of ellipsoid is much more robust than other non-spherical particles. This work offers an alternative approximate procedure besides conventional packing algorithms for studying athermal jamming transition in granular system of frictionless non-spherical particles.

  7. Direct numerical simulation of fluid-particle heat transfer in fixed random arrays of non-spherical particles

    NARCIS (Netherlands)

    Tavassoli Estahbanati, H.; Peters, E.A.J.F.; Kuipers, J.A.M.

    2015-01-01

    Direct numerical simulations are conducted to characterize the fluid-particle heat transfer coefficient in fixed random arrays of non-spherical particles. The objective of this study is to examine the applicability of well-known heat transfer correlations, that are proposed for spherical particles,

  8. Cryogenic surface ion traps

    International Nuclear Information System (INIS)

    Niedermayr, M.

    2015-01-01

    Microfabricated surface traps are a promising architecture to realize a scalable quantum computer based on trapped ions. In principle, hundreds or thousands of surface traps can be located on a single substrate in order to provide large arrays of interacting ions. To this end, trap designs and fabrication methods are required that provide scalable, stable and reproducible ion traps. This work presents a novel surface-trap design developed for cryogenic applications. Intrinsic silicon is used as the substrate material of the traps. The well-developed microfabrication and structuring methods of silicon are utilized to create simple and reproducible traps. The traps were tested and characterized in a cryogenic setup. Ions could be trapped and their life time and motional heating were investigated. Long ion lifetimes of several hours were observed and the measured heating rates were reproducibly low at around 1 phonon per second at a trap frequency of 1 MHz. (author) [de

  9. Magnetoelectric Jones birefringence and dichroism in a medium of free atoms

    International Nuclear Information System (INIS)

    Mironova, P V; Ovsiannikov, V D; Chernushkin, V V

    2006-01-01

    Theoretical treatment of the magnetoelectric Jones birefringence and dichroism is developed through the bilinearity in static electric and magnetic field dipole-forbidden corrections to the amplitude of Rayleigh scattering. In particular cases of orientation of the static fields relative to the polarization and wave vectors of monochromatic radiation, the amplitude determines corrections to the refractive index of atomic gas responsible for (i) the Jones birefringence and dichroism (ii) linear birefringence and dichroism and (iii) directional anisotropy for the monochromatic wave. The analytical equations and numerical data for the indicated corrections, calculated for alkaline-earth-like atoms, determine optimal conditions for observing the effects in vapours. For resonance on 1 D 2 state essential enhancement is discovered in the frequency dependence for the ratio of refractive index anisotropy of the Jones effect to the square-root product of corresponding anisotropies determining the Kerr and Cotton-Mouton effects

  10. Birefringence and incipient plastic deformation in elastically overdriven [100] CaF2 under shock compression

    Science.gov (United States)

    Li, Y.; Zhou, X. M.; Cai, Y.; Liu, C. L.; Luo, S. N.

    2018-04-01

    [100] CaF2 single crystals are shock-compressed via symmetric planar impact, and the flyer plate-target interface velocity histories are measured with a laser displacement interferometry. The shock loading is slightly above the Hugoniot elastic limit to investigate incipient plasticity and its kinetics, and its effects on optical properties and deformation inhomogeneity. Fringe patterns demonstrate different features in modulation of fringe amplitude, including birefringence and complicated modulations. The birefringence is attributed to local lattice rotation accompanying incipient plasticity. Spatially resolved measurements show inhomogeneity in deformation, birefringence, and fringe pattern evolutions, most likely caused by the inhomogeneity associated with lattice rotation and dislocation slip. Transiently overdriven elastic states are observed, and the incubation time for incipient plasticity decreases inversely with increasing overdrive by the elastic shock.

  11. Birefringence and dichroism of poly(vinyl-alcohol) foils containing phthalazinium ylids

    Science.gov (United States)

    Rogojanu, Alina; Dascalu, Carmen Felicia; Zelinschi, Beatrice Carmen; Caprosu, Maria; Dorohoi, Dana Ortansa

    2011-10-01

    Pure and colored with phthalazinium ylids poly(vinyl-alcohol) (PVA) foils were stretched under gentile heating. The birefringence of the thin foils was determined with a Babinet compensator standardized for yellow radiation of a Sodium lamp. The determined birefringence of the colored PVA foils is higher than that of the pure PVA foils. This fact indicates that the phthalazinium ylids facilitate the increase in the anisotropy of the stretched foils. The visible absorption electronic band of phthalazinium ylids was used to estimate the dichroic ratio and the degree of order of the ylid molecules in the stretched PVA foils. An increase in dichroism and birefringence with the degree of stretching has been evidenced for uncolored and colored PVA foils.

  12. Statistical multifragmentation of non-spherical expanding sources in central heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Le Fevre, A. E-mail: a.lefevre@gsi.de; Ploszajczak, M.; Toneev, V.D.; Auger, G.; Begemann-Blaich, M.L.; Bellaize, N.; Bittiger, R.; Bocage, F.; Borderie, B.; Bougault, R.; Bouriquet, B.; Charvet, J.L.; Chbihi, A.; Dayras, R.; Durand, D.; Frankland, J.D.; Galichet, E.; Gourio, D.; Guinet, D.; Hudan, S.; Hurst, B.; Lautesse, P.; Lavaud, F.; Legrain, R.; Lopez, O.; Lukasik, J.; Lynen, U.; Mueller, W.F.J.; Nalpas, L.; Orth, H.; Plagnol, E.; Rosato, E.; Saija, A.; Schwarz, C.; Sfienti, C.; Tamain, B.; Trautmann, W.; Trzcinski, A.; Turzo, K.; Vient, E.; Vigilante, M.; Volant, C.; Zwieglinski, B.; Botvina, A.S

    2004-04-19

    We study the anisotropy effects measured with INDRA at GSI in central collisions of {sup 129}Xe+{sup nat}Sn at 50 A MeV and {sup 197}Au+{sup 197}Au at 60, 80, 100 A MeV incident energy. The microcanonical multifragmentation model with non-spherical sources is used to simulate an incomplete shape relaxation of the multifragmenting system. This model is employed to interpret observed anisotropic distributions in the fragment size and mean kinetic energy. The data can be well reproduced if an expanding prolate source aligned along the beam direction is assumed. An either non-Hubblean or non-isotropic radial expansion is required to describe the fragment kinetic energies and their anisotropy. The qualitative similarity of the results for the studied reactions suggests that the concept of a longitudinally elongated freeze-out configuration is generally applicable for central collisions of heavy systems. The deformation decreases slightly with increasing beam energy.

  13. Gravitational collision efficiency of nonspherical aerosols II: motion of an oblate spheroid in a viscous fluid

    Energy Technology Data Exchange (ETDEWEB)

    Tuttle, R.F.; Loyalka, S.K.

    1985-06-01

    The collisional dynamics of nonspherical aerosols is modeled by the introduction of a shape factor, US . Mechanistic calculation of US requires knowledge of the flow fields around the aerosols. Since actual aerosols can be complicated in shape and since the computation of flow fields can be quite difficult, insights into the nature of US are gained by using the superposition technique and studying aerosols that have tractable flow fields. The motion of an oblate spheroid in a viscous fluid is considered. The Navier-Stokes equations and associated boundary conditions are represented in oblate spheroidal coordinates. A combination of finite differences and spline-interpolation techniques is used to transform these equations to a form suitable for numerical computations. Converged results for the flow fields are obtained for a 0 to 5 range of Reynolds numbers. In the limit of zero Reynolds number, the results are found to be in agreement with the analytical solutions of Oberbeck.

  14. Subluminal and superluminal pulse propagation in inhomogeneous media of nonspherical particles

    International Nuclear Information System (INIS)

    Ma Yu; Gao Lei

    2006-01-01

    We study the pulse propagation through a metal/dielectric composites of nonspherical particles enclosed by two gold mirrors. To account for the shape effect, we first adopt Maxwell-Garnett type approximation to obtain the effective dielectric function of composites. Based on the group index, phase time and pulse shape calculations, we find that the particles' shape (characterized by the depolarization factor) plays an important role in determining the subluminal and superluminal pulse propagations through the system. When the inclusions' shape is not spherical, it is possible to observe significant superluminal behavior of the pulse propagation, although the volume fraction is the same. The shape-dependent critical volume fraction is predicted, above which superluminal propagation appears. Furthermore, the Hartman effect in such a system is also investigated

  15. Macroscopic optical constants of a cloud of randomly oriented nonspherical scatterers

    International Nuclear Information System (INIS)

    Borghese, F.; Denti, P.; Saija, R.; Toscano, G.; Sindoni, O.I.

    1984-01-01

    A method to calculate the macroscopic optical constants of a low-density medium consisting of a cloud of identical nonspherical scatterers is presented. The scatterers in the medium are clusters of dielectric spheres and the electromagnetic field scattered by each of the clusters is obtained as a superposition of multipole fields, as previously proposed by the authors. The transformation properties of the spherical multipoles under rotation allow the orientation-dependent terms in the expression for the forward-scattering amplitude of each of the clusters to be factored out. In this way the sum of the scattering amplitudes of the clusters with different orientations, needed to calculate the optical response of the medium, is greatly facilitated and admits a simple analytic expression in the case of randomly oriented clusters. Results of calculations of the optical constants for a few model media are presented

  16. Non-spherical micelles in an oil-in-water cubic phase

    DEFF Research Database (Denmark)

    Leaver, M.; Rajagopalan, V.; Ulf, O.

    2000-01-01

    phase, both with and without SDS, was established by NMR self-diffusion. In addition H-2 NMR relaxation experiments have demonstrated that the micelles in the cubic phase are non-spherical, having grown and changed shape upon formation of the cubic phase from the micellar solution. Small angle...... associated with the micellar cubic phase, Pm3n and Fd3m. The micellar volumes calculated for these space groups are similar and are consistent with a change in micellar geometry from spherical to prolate.......The cubic phase formed between the microemulsion and hexagonal phases of the ternary pentaethylene glycol dodecyl ether (C12E5)-decane-water system and that doped with small amounts of sodium dodecylsulfate (SDS) have been investigated. The presence of discrete oil-swollen micelles in the cubic...

  17. Optical Modeling of Sea Salt Aerosols: The Effects of Nonsphericity and Inhomogeneity

    Science.gov (United States)

    Bi, Lei; Lin, Wushao; Wang, Zheng; Tang, Xiaoyun; Zhang, Xiaoyu; Yi, Bingqi

    2018-01-01

    The nonsphericity and inhomogeneity of marine aerosols (sea salts) have not been addressed in pertinent radiative transfer calculations and remote sensing studies. This study investigates the optical properties of nonspherical and inhomogeneous sea salts using invariant imbedding T-matrix simulations. Dry sea salt aerosols are modeled based on superellipsoidal geometries with a prescribed aspect ratio and roundness parameter. Wet sea salt particles are modeled as coated superellipsoids, as spherical particles with a superellipsoidal core, and as homogeneous spheres depending on the level of relative humidity. Aspect ratio and roundness parameters are found to be critical to interpreting the linear depolarization ratios (LDRs) of NaCl crystals from laboratory measurements. The optimal morphology parameters of NaCl necessary to reproduce the measurements are found to be consistent with data gleaned from an electron micrograph. The LDRs of wet sea salts are computed based on inhomogeneous models and compared with the measured data from ground-based LiDAR. The dependence of the LDR on relative humidity is explicitly considered. The increase in the LDR with relative humidity at the initial phase of deliquescence is attributed to both the size increase and the inhomogeneity effect. For large humidity values, the LDR substantially decreases because the overall particle shape becomes more spherical and the inhomogeneity effect in a particle on the LDR is suppressed for submicron sea salts. However, the effect of inhomogeneity on optical properties is pronounced for coarse-mode sea salts. These findings have important implications for atmospheric radiative transfer and remote sensing involving sea salt aerosols.

  18. The necessity of microscopy to characterize the optical properties of size-selected, nonspherical aerosol particles.

    Science.gov (United States)

    Veghte, Daniel P; Freedman, Miriam A

    2012-11-06

    It is currently unknown whether mineral dust causes a net warming or cooling effect on the climate system. This uncertainty stems from the varied and evolving shape and composition of mineral dust, which leads to diverse interactions of dust with solar and terrestrial radiation. To investigate these interactions, we have used a cavity ring-down spectrometer to study the optical properties of size-selected calcium carbonate particles, a reactive component of mineral dust. The size selection of nonspherical particles like mineral dust can differ from spherical particles in the polydispersity of the population selected. To calculate the expected extinction cross sections, we use Mie scattering theory for monodisperse spherical particles and for spherical particles with the polydispersity observed in transmission electron microscopy images. Our results for calcium carbonate are compared to the well-studied system of ammonium sulfate. While ammonium sulfate extinction cross sections agree with Mie scattering theory for monodisperse spherical particles, the results for calcium carbonate deviate at large and small particle sizes. We find good agreement for both systems, however, between the calculations performed using the particle images and the cavity ring-down data, indicating that both ammonium sulfate and calcium carbonate can be treated as polydisperse spherical particles. Our results indicate that having an independent measure of polydispersity is essential for understanding the optical properties of nonspherical particles measured with cavity ring-down spectroscopy. Our combined spectroscopy and microscopy techniques demonstrate a novel method by which cavity ring-down spectroscopy can be extended for the study of more complex aerosol particles.

  19. Effect of pH, ethanol concentration, and temperature on detection of quagga mussel (Dreissena bugensis birefringence

    Directory of Open Access Journals (Sweden)

    Scott O’Meara

    2013-05-01

    Full Text Available In the western United States, federal, state, and local agencies have engaged in extensive efforts to detect the presence of larval dreissenid mussels (veligers in water bodies before such a presence becomes a full-scale infestation. Cross-polarized light microscopy (CPLM is commonly used to detect the veliger’s specific birefringence pattern, but the effect of sample preservation on dreissenid birefringence has not yet been determined. This study examined the effects of solution pH, ethanol concentration, and storage temperature on veliger birefringence loss. Birefringence loss was determined by examining veligers under CPLM at regular intervals over a 30 day period. Veliger birefringence loss was below five percent in all basic solutions, regardless of holding temperature or ethanol concentration. Veliger birefringence loss was also below five percent in acidic solutions that were refrigerated or contained 50–70 percent ethanol. Veligers in acidic solutions that were held at 25°C and 34°C with 0–25 percent ethanol had 7–25 percent veliger birefringence loss over a 30 day period. While ethanol addition and refrigeration are both important preservation methods, the results of this study indicate that samples collected for dreissenid veliger detection by CPLM must also be maintained at a basic pH in order to preserve veliger shell integrity and birefringence. Determining the best conditions for long-term preservation of veliger shells requires further investigation, and these results should not be assumed best for analyses other than CPLM.

  20. Birefringence Polarimeter Using Dual LiNbO3 Electrooptic Crystal Modulators

    Science.gov (United States)

    Saitou, Takeshi; Nurdin Bin, Muhammad; Kowa, Hiroyuki; Umeda, Norihiro; Takizawa, Kuniharu; Kondoh, Eiichi; Jin, Lianhua

    2012-08-01

    A birefringence polarimeter that uses dual LiNbO3 electrooptic crystal modulators operating at a frequency ratio of 4:1 is described. The significance of this polarimeter is that the birefringent parameters of a sample are obtained only from the modulated polarization status. The measurement, therefore, avoids depolarization effects resulting from the sample itself and the rest of the optical system. The high speed and accuracy of this polarimeter are shown by measurements using a quarter-wave plate, a Babinet-Soleil compensator, and a phase modulator.

  1. Analytical investigation of response of birefringent fiber Bragg grating sensors in distributed monitoring system based on optical frequency domain reflectometry

    Science.gov (United States)

    Wada, D.; Murayama, H.

    2014-01-01

    When Fiber Bragg gratings (FBGs) are used as strain sensors, both longitudinal and lateral strain can be applied uniformly or non-uniformly over the length of the FBGs. In order for the demodulation of such FBG signal, this paper investigates the response of birefringent FBGs which are monitored by distributed measurement system based on optical frequency domain reflectometry. A numerical model of the distributed measurement system is built based on piece-wise uniform approach, which considers polarization states of propagating lights. The numerical model simulates analytical response of birefringent FBGs especially when birefringence induces power fluctuations in the distributed spectra, which can be noise or new opportunity for sensitive monitoring of birefringence. Simulation results show the relationships between the power fluctuations and the polarization states of the propagating lights. Consequently, appropriate methods of polarization control for sensitive distributed birefringent FBG monitoring are discussed.

  2. Birefringence Optical Feedback with a Folded Cavity in HeNe Laser

    International Nuclear Information System (INIS)

    Wu Yun; Tan Yi-Dong

    2013-01-01

    The birefringence optical feedback with a folded cavity in HeNe laser is investigated. A theory model based on the equivalent cavity of the Fabry—Perot interferometer is presented. The phase difference between the two intensities in birefringence feedback is twice the retardation of the wave plate. The phase difference is invariable when the length of the feedback cavity changes. With the adoption of a cube corner prism (CCP) to form a folded cavity, the fringe frequency is doubled, and the resolution of the displacement sensor based on birefringence optical feedback with a folded cavity is improved. A resistance chain of 5-fold subdivision and 4-fold logic subdivision is used as further subdivision. The resolution of λ/80 is obtained eventually; for 632.8 nm HeNe laser it is 7.91 nm. The displacement sensor based on birefringence optical feedback with a folded cavity is simple and of high resolution, large measurement range, low cost, and is of great application potential in industry

  3. Stochastic theory of polarized light in nonlinear birefringent media: An application to optical rotation

    Science.gov (United States)

    Tsuchida, Satoshi; Kuratsuji, Hiroshi

    2018-05-01

    A stochastic theory is developed for the light transmitting the optical media exhibiting linear and nonlinear birefringence. The starting point is the two-component nonlinear Schrödinger equation (NLSE). On the basis of the ansatz of “soliton” solution for the NLSE, the evolution equation for the Stokes parameters is derived, which turns out to be the Langevin equation by taking account of randomness and dissipation inherent in the birefringent media. The Langevin equation is converted to the Fokker-Planck (FP) equation for the probability distribution by employing the technique of functional integral on the assumption of the Gaussian white noise for the random fluctuation. The specific application is considered for the optical rotation, which is described by the ellipticity (third component of the Stokes parameters) alone: (i) The asymptotic analysis is given for the functional integral, which leads to the transition rate on the Poincaré sphere. (ii) The FP equation is analyzed in the strong coupling approximation, by which the diffusive behavior is obtained for the linear and nonlinear birefringence. These would provide with a basis of statistical analysis for the polarization phenomena in nonlinear birefringent media.

  4. Light-induced circular birefringence in cyanoazobenzene side-chain liquid-crystalline polyester films

    DEFF Research Database (Denmark)

    Naydenova, I; Nikolova, L; Ramanujam, P.S.

    1999-01-01

    We report the inducement of large circular birefringence (optical activity) in films of a cyanoazobenzene side-chain liquid-crystalline polyester on illumination with circularly polarized light. The polyester has no chiral groups and is initially isotropic. The induced optical rotation is up to 5...

  5. Temperature and composition dependence of birefringence of lithium-tantalate crystals determined by holographic scattering

    International Nuclear Information System (INIS)

    Bastwoeste, K.; Schwalenberg, S.; Baeumer, Ch.; Kraetzig, E.

    2003-01-01

    Iron-doped lithium-tantalate samples with different compositions ranging from the congruently melting to the stoichiometric one are analyzed by anisotropic holographic scattering. The temperature dependence of the birefringence yields information on the composition of the crystals. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Temperature and composition dependence of birefringence of lithium-tantalate crystals determined by holographic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bastwoeste, K.; Schwalenberg, S.; Baeumer, Ch.; Kraetzig, E. [Fachbereich Physik, Universitaet Osnabrueck, D-49069 Osnabrueck (Germany)

    2003-09-01

    Iron-doped lithium-tantalate samples with different compositions ranging from the congruently melting to the stoichiometric one are analyzed by anisotropic holographic scattering. The temperature dependence of the birefringence yields information on the composition of the crystals. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. LiTaO.sub.3./sub. crystals with near-zero birefringence

    Czech Academy of Sciences Publication Activity Database

    Glazier, A. M.; Zhang, N.; Bartasyte, A.; Keeble, D.S.; Huband, S.; Thomas, P.A.; Gregora, Ivan; Borodavka, Fedir; Margueron, S.; Hlinka, Jiří

    2012-01-01

    Roč. 45, č. 5 (2012), s. 1030-1037 ISSN 0021-8898 Institutional research plan: CEZ:AV0Z10100520 Keywords : lithium tantalate * birefringence * domains * Raman spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.343, year: 2012

  8. The new PVLAS apparatus for detection of magnetic birefringence of vacuum

    International Nuclear Information System (INIS)

    Della Valle, F.; Di Domenico, G.; Gastaldi, U.; Milotti, E.; Messineo, G.; Pengo, R.; Piemontese, L.; Ruoso, G.; Zavattini, G.

    2013-01-01

    The PVLAS experiment aims at the observation and measurement of the effect of magnetic birefringence of vacuum (MBV) predicted by Quantum Electrodynamics. We describe here the new PVLAS apparatus which is currently being set up in INFN Ferrara. The apparatus features two rotating permanent dipole magnets and an ellipsometer operating under UHV with a high finesse Fabry–Perot cavity

  9. First results from the new PVLAS apparatus: A new limit on vacuum magnetic birefringence

    Science.gov (United States)

    Della Valle, F.; Milotti, E.; Ejlli, A.; Messineo, G.; Piemontese, L.; Zavattini, G.; Gastaldi, U.; Pengo, R.; Ruoso, G.

    2014-11-01

    Several groups are carrying out experiments to observe and measure vacuum magnetic birefringence, predicted by quantum electrodynamics (QED). We have started running the new PVLAS apparatus installed in Ferrara, Italy, and have measured a noise floor value for the unitary field magnetic birefringence of vacuum Δ nu(vac )=(4 ±20 )×1 0-23 T-2 (the error represents a 1 σ deviation). This measurement is compatible with zero and hence represents a new limit on vacuum magnetic birefringence deriving from nonlinear electrodynamics. This result reduces to a factor of 50 the gap to be overcome to measure for the first time the value of Δ nu(vac ,QED ) predicted by QED: Δ nu(vac ,QED )=4 ×10-24 T-2 . These birefringence measurements also yield improved model-independent bounds on the coupling constant of axion-like particles to two photons, for masses greater than 1 meV, along with a factor-2 improvement of the fractional charge limit on millicharged particles (fermions and scalars), including neutrinos.

  10. A complex-polarization-propagator protocol for magneto-chiral axial dichroism and birefringence dispersion

    DEFF Research Database (Denmark)

    Cukras, Janusz; Kauczor, Joanna; Norman, Patrick

    2016-01-01

    A computational protocol for magneto-chiral dichroism and magneto-chiral birefringence dispersion is presented within the framework of damped response theory, also known as complex polarization propagator theory, at the level of time-dependent Hartree–Fock and time-dependent density functional th...

  11. Shrew trap efficiency

    DEFF Research Database (Denmark)

    Gambalemoke, Mbalitini; Mukinzi, Itoka; Amundala, Drazo

    2008-01-01

    We investigated the efficiency of four trap types (pitfall, Sherman LFA, Victor snap and Museum Special snap traps) to capture shrews. This experiment was conducted in five inter-riverine forest blocks in the region of Kisangani. The total trapping effort was 6,300, 9,240, 5,280 and 5,460 trap......, our results indicate that pitfall traps are the most efficient for capturing shrews: not only do they have a higher efficiency (yield), but the taxonomic diversity of shrews is also higher when pitfall traps are used....

  12. The measurement system of birefringence and Verdet constant of optical fiber

    Science.gov (United States)

    Huang, Yi; Chen, Li; Guo, Qiang; Pang, Fufei; Wen, Jianxiang; Shang, Yana; Wang, Tingyun

    2013-12-01

    The Faraday magneto-optical effect of optical fiber has many applications in monitoring magnetic field and electric current. When a linearly polarized light propagates in the direction of a magnetic field, the plane of polarization will rotate linearly proportional to the strength of the applied magnetic field, which following the relationship of θF =VBl. θF is the Faraday rotation angle, which is proportional to the magnetic flux density B and the Verdet constant V . However, when the optical fiber contains the effect of linear birefringence, the detection of Faraday rotation angle will depend on the line birefringence. In order to determine the Verdet constant of an optical fiber under a linear birefringence, the fiber birefringence needs to be accurately measured. In this work, a model is applied to analyze the polarization properties of an optical fiber by using the Jones matrix method. A measurement system based on the lock-in amplifier technology is designed to test the Verdet constant and the birefringence of optical fiber. The magnetic field is produced by a solenoid with a DC current. A tunable laser is intensity modulated with a motorized rotating chopper. The actuator supplies a signal as the phase-locked synchronization reference to the signal of the lock-in amplifier. The measurement accuracy is analyzed and the sensitivity of the system is optimized. In this measurement system, the Verdet constant of the SMF-28 fiber was measured to be 0.56±0.02 rad/T·m at 1550nm. This setup is well suitable for measuring the high signal-to-noise ratio (SNR) sensitivity for lock-in amplifier at a low magnetic field strength.

  13. St. Croix trap study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data set contains detailed information about the catch from 600 trap stations around St. Croix. Data fields include species caught, size data, trap location...

  14. A development of two-dimensional birefringence distribution measurement system with a sampling rate of 1.3 MHz

    Science.gov (United States)

    Onuma, Takashi; Otani, Yukitoshi

    2014-03-01

    A two-dimensional birefringence distribution measurement system with a sampling rate of 1.3 MHz is proposed. A polarization image sensor is developed as core device of the system. It is composed of a pixelated polarizer array made from photonic crystal and a parallel read out circuit with a multi-channel analog to digital converter specialized for two-dimensional polarization detection. By applying phase shifting algorism with circularly-polarized incident light, birefringence phase difference and azimuthal angle can be measured. The performance of the system is demonstrated experimentally by measuring actual birefringence distribution and polarization device such as Babinet-Soleil compensator.

  15. Angular trap for macroparticles

    International Nuclear Information System (INIS)

    Aksyonov, D.S.

    2013-01-01

    Properties of angular macroparticle traps were investigated in this work. These properties are required to design vacuum arc plasma filters. The correlation between trap geometry parameters and its ability to absorb macroparticles were found. Calculations allow one to predict the behaviour of filtering abilities of separators which contain such traps in their design. Recommendations regarding the use of angular traps in filters of different builds are given.

  16. Radiation drag in the field of a non-spherical source

    Science.gov (United States)

    Bini, D.; Geralico, A.; Passamonti, A.

    2015-01-01

    The motion of a test particle in the gravitational field of a non-spherical source endowed with both mass and mass quadrupole moment is investigated when a test radiation field is also present. The background is described by the Erez-Rosen solution, which is a static space-time belonging to the Weyl class of solutions to the vacuum Einstein's field equations, and reduces to the familiar Schwarzschild solution when the quadrupole parameter vanishes. The radiation flux has a fixed but arbitrary (non-zero) angular momentum. The interaction with the radiation field is assumed to be Thomson-like, i.e. the particles absorb and re-emit radiation, thus suffering for a friction-like drag force. Such an additional force is responsible for the Poynting-Robertson effect, which is well established in the framework of Newtonian gravity and has been recently extended to the general theory of relativity. The balance between gravitational attraction, centrifugal force and radiation drag leads to the occurrence of equilibrium circular orbits which are attractors for the surrounding matter for every fixed value of the interaction strength. The presence of the quadrupolar structure of the source introduces a further degree of freedom: there exists a whole family of equilibrium orbits parametrized by the quadrupole parameter, generalizing previous works. This scenario is expected to play a role in the context of accretion matter around compact objects.

  17. Gauge-invariant non-spherical metric perturbations of Schwarzschild black-hole spacetimes

    International Nuclear Information System (INIS)

    Nagar, Alessandro; Rezzolla, Luciano

    2005-01-01

    The theory of gauge-invariant non-spherical metric perturbations of Schwarzschild black-hole spacetimes is now well established. Yet, as different notations and conventions have been used throughout the years, the literature on the subject is often confusing and sometimes confused. The purpose of this review is to review and collect the relevant expressions related to the Regge-Wheeler and Zerilli equations for the odd and even-parity perturbations of a Schwarzschild spacetime. Special attention is paid to the form they assume in the presence of matter-sources and, for the two most popular conventions in the literature, to the asymptotic expressions and gravitational-wave amplitudes. Besides pointing out some inconsistencies in the literature, the expressions collected here could serve as a quick reference for the calculation of the perturbations of a Schwarzschild black-hole spacetime driven by generic sources and for those approaches in which gravitational waves are extracted from numerically generated spacetimes. (topical review)

  18. Controlling placement of nonspherical (boomerang) colloids in nematic cells with photopatterned director

    International Nuclear Information System (INIS)

    Peng, Chenhui; Turiv, Taras; Guo, Yubing; Shiyanovskii, Sergij V; Wei, Qi-Huo; Lavrentovich, Oleg D; Zhang, Rui; De Pablo, Juan

    2017-01-01

    Placing colloidal particles in predesigned sites represents a major challenge of the current state-of-the-art colloidal science. Nematic liquid crystals with spatially varying director patterns represent a promising approach to achieve a well-controlled placement of colloidal particles thanks to the elastic forces between the particles and the surrounding landscape of molecular orientation. Here we demonstrate how the spatially varying director field can be used to control placement of non-spherical particles of boomerang shape. The boomerang colloids create director distortions of a dipolar symmetry. When a boomerang particle is placed in a periodic splay-bend director pattern, it migrates towards the region of a maximum bend. The behavior is contrasted to that one of spherical particles with normal surface anchoring, which also produce dipolar director distortions, but prefer to compartmentalize into the regions with a maximum splay. The splay-bend periodic landscape thus allows one to spatially separate these two types of particles. By exploring overdamped dynamics of the colloids, we determine elastic driving forces responsible for the preferential placement. Control of colloidal locations through patterned molecular orientation can be explored for future applications in microfluidic, lab on a chip, sensing and sorting devices. (paper)

  19. Controlling placement of nonspherical (boomerang) colloids in nematic cells with photopatterned director

    Science.gov (United States)

    Peng, Chenhui; Turiv, Taras; Zhang, Rui; Guo, Yubing; Shiyanovskii, Sergij V.; Wei, Qi-Huo; de Pablo, Juan; Lavrentovich, Oleg D.

    2017-01-01

    Placing colloidal particles in predesigned sites represents a major challenge of the current state-of-the-art colloidal science. Nematic liquid crystals with spatially varying director patterns represent a promising approach to achieve a well-controlled placement of colloidal particles thanks to the elastic forces between the particles and the surrounding landscape of molecular orientation. Here we demonstrate how the spatially varying director field can be used to control placement of non-spherical particles of boomerang shape. The boomerang colloids create director distortions of a dipolar symmetry. When a boomerang particle is placed in a periodic splay-bend director pattern, it migrates towards the region of a maximum bend. The behavior is contrasted to that one of spherical particles with normal surface anchoring, which also produce dipolar director distortions, but prefer to compartmentalize into the regions with a maximum splay. The splay-bend periodic landscape thus allows one to spatially separate these two types of particles. By exploring overdamped dynamics of the colloids, we determine elastic driving forces responsible for the preferential placement. Control of colloidal locations through patterned molecular orientation can be explored for future applications in microfluidic, lab on a chip, sensing and sorting devices.

  20. Transverse components of the radiation force on nonspherical particles in the T-matrix formalism

    International Nuclear Information System (INIS)

    Saija, Rosalba; Antonia Iati, Maria; Giusto, Arianna; Denti, Paolo; Borghese, Ferdinando

    2005-01-01

    In the framework of the transition matrix approach, we calculate the force exerted by a plane wave (radiation force) on a dispersion of nonspherical particles modeled as aggregates of spheres. Beyond the customary radiation pressure we also consider the components of the radiation force in a plane orthogonal to the direction of incidence of the incoming wave (transverse components). Our calculations show that, although the latter are generally smaller than the radiation pressure, they are in no way negligible and may be important for some applications, e.g. when studying the dynamics of cosmic dust grains. We also calculate the ensemble average of the components of the radiation force over the orientation of the particles in two physically significant cases: the case of random distribution and the case in which the orientations are randomly distributed around an axis fixed in space (axial average). As expected, we find that, unlike the case of random orientation, the transverse components do not vanish for axial average

  1. Numerical determination of the effective moments of non-spherical particles

    International Nuclear Information System (INIS)

    Green, Nicolas G; Jones, Thomas B

    2007-01-01

    Dielectric characterisation of polarisable particles, and prediction of the forces and torques exerted upon them, relies on the knowledge of the effective, induced dipole moment. In turn, through the mechanism of depolarisation, the induced dipole moment of a particle is strongly dependent upon its shape. Since realistic shapes create modelling difficulties, the 'spherical particle' approximation is often invoked. However, in many cases, including biological dielectric spectroscopy and dielectrophoresis, this assumption is a poor one. For example, human erythrocytes are essentially oblate spheroids with indented sides, while viruses and bacteria often have elongated cigar shapes. Since shape-dependent polarisation both strongly influences the accuracy of conventional dielectric characterisation methods using Maxwell's mixture formula and confounds accurate prediction of dielectrophoretic forces and torques, it is important to develop means to treat non-spherical particles. In this paper, we demonstrate a means to extract the dipole moment directly from numerical solutions of the induced electrostatic potential when a particle is placed in a uniform electric field. The accuracy of the method is demonstrated for a range of particle shapes: spherical, ellipsoidal, truncated cylinders and an approximation of an erythrocyte, the red blood cell

  2. Effects of snow grain non-sphericity on climate simulations: Sensitivity tests with the NorESM model

    Science.gov (United States)

    Räisänen, Petri; Makkonen, Risto; Kirkevåg, Alf

    2017-04-01

    Snow grains are non-spherical and generally irregular in shape. Still, in radiative transfer calculations, they are often treated as spheres. This also applies to the computation of snow albedo in the Snow, Ice, and Aerosol Radiation (SNICAR) model and in the Los Alamos sea ice model, version 4 (CICE4), both of which are employed in the Community Earth System Model and in the Norwegian Earth System Model (NorESM). In this work, we evaluate the effect of snow grain shape on climate simulated by NorESM in a slab ocean configuration of the model. An experiment with spherical snow grains (SPH) is compared with another (NONSPH) in which the snow shortwave single-scattering properties are based on a combination of non-spherical snow grain shapes optimized using measurements of angular scattering by blowing snow. The key difference between these treatments is that the asymmetry parameter is smaller in the non-spherical case (≈ 0.78 in the visible region) than in the spherical case (≈ 0.89). Therefore, for a given snow grain size, the use of non-spherical snow grains yields a higher snow broadband albedo, typically by ≈0.03. Consequently, considering the spherical case as the baseline, the use of non-spherical snow grains results in a negative radiative forcing (RF), with a global-mean top-of-the-model value of ≈ -0.22 W m-2. Although this global-mean RF is modest, it has a rather substantial impact on the climate simulated by NoRESM. In particular, the global annual-mean 2-m air temperature in NONSPH is 1.17 K lower than in SPH, with substantially larger differences at high latitudes. The climatic response is amplified by strong snow and sea ice feedbacks. It is further found that the difference between NONSPH and SPH could be largely "tuned away" by adjusting the snow grain size in the NONSPH experiment by ≈ 70%. The impact of snow grain shape on the radiative effect (RE) of absorbing aerosols in snow (black carbon and mineral dust) is also discussed. For an

  3. Influence of UV and Gamma radiations on the induced birefringence of stretched poly(vinyl) alcohol foils

    Science.gov (United States)

    Nechifor, Cristina-Delia; Zelinschi, Carmen Beatrice; Dorohoi, Dana-Ortansa

    2014-03-01

    The aim of our paper is to evidence the influence of Gamma and UV radiations on the induced birefringence of poly(vinyl alcohol) stretched foils. Thin foils of PVA were prepared and dried without modifying their surfaces. The polymeric foils were irradiated from 15 min to 6 h using UV and Gamma radiations. The induced by stretching under heating birefringence of PVA films was measured at λ = 589.3 nm with a Babinet Compensator. Physico-chemical processes (photo stabilization, photo degradation, oxidation) induced by irradiation of polymer matrix influence both the stretching degree and the anisotropy of etired foils. An increase of birefringence versus the stretching ratio of the PVA foils was evidenced for all studied samples. The dependence of the birefringence on the exposure time, stretching ratio and nature of radiation was also confirmed.

  4. Removing left-right asymmetry in a Sagnac interferometer applied to cancel its reflectance dependence on birefringence.

    Science.gov (United States)

    Golub, Ilya; Exir, Hourieh

    2013-05-01

    We present a left-right symmetry restoring method, which removes the detrimental birefringence in the single-mode fiber Sagnac interferometer, achieved with the aid of a half waveplate oriented at a specific angle. We show theoretically and demonstrate experimentally that adding a π-shift between clockwise and counterclockwise propagating, horizontally (in fiber loop plane) polarized field components, the Sagnac loop mirror's reflection becomes independent on birefringence of an element placed in the loop.

  5. Measurement of stress-induced birefringence in glasses based on reflective laser feedback effect

    Science.gov (United States)

    Haisha, Niu; YanXiong, Niu; Jiyang, Li

    2017-02-01

    A glass birefringence measurement system utilizing the reflective laser feedback (RLF) effect is presented. The measurement principle is analyzed based on the equivalent cavity of a Fabry-Perot interferometer, and the experiments are conducted with a piece of quartz glass with applied extrusion force. In the feedback system, aluminum film used as a feedback mirror is affixed to the back of the sample. When the light is reflected back into the cavity, as the reinjected light is imprinted with the birefringence information in the sample, the gain and polarization states of the laser are modulated. The variation of optical power and polarization states hopping is monitored to obtain the magnitude of the stress. The system has advantages such as simplicity and low-cost with a precision of 1.9 nm. Moreover, by adjusting the position of the aluminum, large-area samples can be measured anywhere at any place.

  6. Flexible transparent aerogels as window retrofitting films and optical elements with tunable birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qingkun; Frazier, Allister W.; Zhao, Xinpeng; De La Cruz, Joshua A.; Hess, Andrew J.; Yang, Ronggui; Smalyukh, Ivan I.

    2018-06-01

    Experimental realization of optically transparent, mechanically robust and flexible aerogels has been a longstanding challenge, which limits their practical applications in energy-saving devices, such as thermally insulating films for enhancing energy efficiency of windows. The poor transparency precluded even hypothetical consideration of the possibility of birefringent aerogels. We develop birefringent and optically isotropic aerogels that combine properties of thermal super-insulation, mechanical robustness and flexibility, and transparency to visible-spectrum light. This unusual combination of physical properties is achieved by combining liquid crystalline self-organization of cellulose nanofibers with polysiloxane cross-linking and control of the nanoscale porosity to form hybrid organic-inorganic mesostructured aerogels. Potential applications of these inexpensive materials range from single pane window retrofitting to smart fabrics.

  7. Quantitative orientational characterization if low - density polyethylene blow films by x-ray and birefringence

    International Nuclear Information System (INIS)

    Taheri Qazvini, N.; Mohammadi, N.; Ghaffarian, R.; Assempour, H.; Haghighatkish, M.

    2002-01-01

    The effect of two important parameters of film blowing processes, i.e., take-up ration and blow-up ratio, on the overall orientation of low-density blown films have been investigated using birefringence measurements. Furthermore, by combining x-ray diffraction pole figure analysis and birefringence, the White and Spruiell biaxial orientation functions have been determined for aforementioned sample. Within the range of processing condition studied, increasing take-up ratio, increases orientation in both machine and transverse direction. Upon increasing blow-up ratio, orientation in the transverse direction increases and the overall orientation state approaches to equal biaxial one. Characterization of the crystalline regions by pole figure analysis reveals that a and b crystallographic axes preferentially orientate in the film plane and the direction normal to it, respectively. The amorphous regions do not have any preferential orientation

  8. Improvement of chirped pulse contrast using electro-optic birefringence scanning filter method

    International Nuclear Information System (INIS)

    Zeng Shuguang; Wang Xianglin; Wang Qishan; Zhang Bin; Sun Nianchun; Wang Fei

    2013-01-01

    A method using scanning filter to improve the contrast of chirped pulse is proposed, and the principle of this method is analyzed. The scanning filter is compared with the existing pulse-picking technique and nonlinear filtering technique. The scanning filter is a temporal gate that is independent on the intensity of the pulses, but on the instantaneous wavelengths of light. Taking the electro-optic birefringence scanning filter as an example, the application of scanning filter methods is illustrated. Based on numerical simulation and experimental research, it is found that the electro-optic birefringence scanning filter can eliminate a prepulse which is several hundred picoseconds before the main pulse, and the main pulse can maintain a high transmissivity. (authors)

  9. Stress induced birefringence in hybrid TIR/PBG guiding solid photonic crystal fibers

    DEFF Research Database (Denmark)

    Lyngsøe, Jens Kristian; Mangan, Brian Joseph; Olausson, Christina Bjarnal Thulin

    2010-01-01

    We report on two types of polarization maintaining solid photonic crystal fibers that guide light by a combination of a photonic bandgap and total internal reflection. Group and phase birefringence are studied experimentally and numerically for stress-applying parts made from B-doped and F......-doped silica. The stress field originating from Ge-doped cladding rods is shown to interfere with the stress field from the B-doped and F-doped rods. Since the differential expansion coefficients of B-doped and F-doped silica have opposite signs this interference is either destructive or constructive....... Consequently, we found that the fiber with F-doped stress applying parts has the highest modal phase birefringence, and polarization cross talk is characterized by an h-parameter below 3⋅10−5 m−1....

  10. Polarization holograms in a bifunctional amorphous polymer exhibiting equal values of photoinduced linear and circular birefringences.

    Science.gov (United States)

    Provenzano, Clementina; Pagliusi, Pasquale; Cipparrone, Gabriella; Royes, Jorge; Piñol, Milagros; Oriol, Luis

    2014-10-09

    Light-controlled molecular alignment is a flexible and useful strategy introducing novelty in the fields of mechanics, self-organized structuring, mass transport, optics, and photonics and addressing the development of smart optical devices. Azobenzene-containing polymers are well-known photocontrollable materials with large and reversible photoinduced optical anisotropies. The vectorial holography applied to these materials enables peculiar optical devices whose properties strongly depend on the relative values of the photoinduced birefringences. Here is reported a polarization holographic recording based on the interference of two waves with orthogonal linear polarization on a bifunctional amorphous polymer that, exceptionally, exhibits equal values of linear and circular birefringence. The peculiar photoresponse of the material coupled with the holographic technique demonstrates an optical device capable of decomposing the light into a set of orthogonally polarized linear components. The holographic structures are theoretically described by the Jones matrices method and experimentally investigated.

  11. Detecting relic gravitational waves in the CMB: The contamination caused by the cosmological birefringence

    Directory of Open Access Journals (Sweden)

    Wen Zhao

    2014-10-01

    Full Text Available The B-mode polarization of the cosmic microwave background (CMB radiation is an excellent information channel for the detection of relic gravitational waves. However, the detection is contaminated by the B-mode polarization generated by some other effects. In this paper, we discuss the contaminations caused by the cosmological birefringence, which converts the CMB E-mode to the B-mode, and forms the effective noise for the detection of gravitational waves. We find that this contamination is significant, if the rotation angle is large. However, this kind of B-mode can be properly de-rotated, and the effective noises can be greatly reduced. We find that, comparing with the contaminations caused by cosmic weak lensing, the residual polarization generated by the cosmological birefringence is negligible for the detection of relic gravitational waves in the CMB.

  12. Study of the Magnetically Induced QED Birefringence of the Vacuum in experiment OSQAR

    CERN Document Server

    AUTHOR|(CDS)2083980

    Classical electrodynamics in a vacuum is a linear theory and does not foresee photon-photon scattering or other nonlinear effects between electromagnetic fields. In 1936 Euler, Heisenberg and Weisskopf put framework, in the earliest development of quantum electrodynamics (QED), that vacuum can behave as a birefringent medium in the presence of the external transverse magnetic field. This phenomenon is known as Vacuum Magnetic Birefringence (VMB) and it is still challenging for optical metrology since the first calculations in 1970. When linearly polarized light travels through the strong transverse magnetic field in vacuum, the polarization state of the light would change to elliptical. The difference in the refraction indexes of the ordinary and extraordinary ray is directly related to fundamental constants, such as fine structure constant or Compton wavelength. Contributions to VMB could also arise from the existence of light scalar or pseudoscalar particles, such as axions or axions like particles. Axions ...

  13. Terahertz polarization converter based on all-dielectric high birefringence metamaterial with elliptical air holes

    KAUST Repository

    Zi, Jianchen

    2018-02-15

    Metamaterials have been widely applied in the polarization conversion of terahertz (THz) waves. However, common plasmonic metamaterials usually work as reflective devices and have low transmissions. All-dielectric metamaterials can overcome these shortcomings. An all-dielectric metamaterial based on silicon with elliptical air holes is reported to achieve high artificial birefringence at THz frequencies. Simulations show that with appropriate structural parameters the birefringence of the dielectric metamaterial can remain flat and is above 0.7 within a broad band. Moreover, the metamaterial can be designed as a broadband quarter wave plate. A sample metamaterial was fabricated and tested to prove the validity of the simulations, and the sample could work as a quarter wave plate at 1.76 THz. The all-dielectric metamaterial that we proposed is of great significance for high performance THz polarization converters.

  14. Highly birefringent phase-shifted fiber Bragg gratings inscribed with femtosecond laser.

    Science.gov (United States)

    He, Jun; Wang, Yiping; Liao, Changrui; Wang, Qiaoni; Yang, Kaiming; Sun, Bing; Yin, Guolu; Liu, Shen; Zhou, Jiangtao; Zhao, Jing

    2015-05-01

    We demonstrate a highly birefringent phase-shifted fiber Bragg grating (PS-FBG) inscribed in H2-free fiber with a near-infrared femtosecond Gaussian laser beam and uniform phase mask. The PS-FBG was fabricated from an ordinary fiber Bragg grating (FBG) in a case in which overexposure was applied. The spectral evolution from FBG to FS-FBG was observed experimentally with a decrease in transmission loss at dip wavelength, blueshift of the dip wavelength, decrease in the cladding mode loss, and an increase in the insertion loss. A high birefringence was demonstrated experimentally with the existence of PS-FBG only in TM polarization. The formation of the PS-FBG may be due to a negative index change induced by the higher intensity in the center of the Gaussian laser beam.

  15. Distributed strain measurement using modal interference in a birefringent optical fiber

    International Nuclear Information System (INIS)

    Kumar, Dilip; Sengupta, S; Ghorai, S K

    2008-01-01

    We propose a method based on modal interference in a birefringent optical fiber for distributed strain measurement. A frequency-modulated optical signal from a laser diode was launched in a birefringent fiber whose 'V' number was set in the range 2.405–3.831. The beat signal produced due to the interference of two lower order modes LP 01 and LP 11 was detected in a photodetector. The change in propagation constants between two modes under loading conditions leads to a phase variation of interference signal. The amplitude of the beat frequency was measured in the frequency domain by varying the modulating frequency, and it provides the measurand distribution along the beam. Results for strain distribution of a simply supported beam (51.0 cm × 3.0 cm × 0.6 cm) for an applied load of 250–1500 g are presented

  16. A note on the birefringence angle estimation in CMB data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gruppuso, A. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via P. Gobetti 101, I-40129 Bologna (Italy); Maggio, G. [INAF, Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, Trieste (Italy); Molinari, D.; Natoli, P., E-mail: gruppuso@iasbo.inaf.it, E-mail: maggio@oats.inaf.it, E-mail: molinari@iasfbo.inaf.it, E-mail: ntlpla@unife.it [Dipartimento di Fisica e Scienze della Terra and INFN, Università degli Studi di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy)

    2016-05-01

    Parity violating physics beyond the standard model of particle physics induces a rotation of the linear polarization of photons. This effect, also known as cosmological birefringence (CB), can be tested with the observations of the cosmic microwave background (CMB) anisotropies which are linearly polarized at the level of 5–10%. In particular CB produces non-null CMB cross correlations between temperature and B mode-polarization, and between E- and B-mode polarization. Here we study the properties of the so called D-estimators, often used to constrain such an effect. After deriving the framework of both frequentist and Bayesian analysis, we discuss the interplay between birefringence and weak-lensing, which, albeit parity conserving, modifies pre-existing TB and EB cross correlation.

  17. Imaging of irradiated human costal cartilage birefringence by PS-OCT

    International Nuclear Information System (INIS)

    Martinho Junior, Antonio C.; Freitas, Anderson Z.; Santin, Stefany P.; Soares, Fernando A.N.; Mosca, Rodrigo C.; Bringel, Fabiana A.; Mathor, Monica B.

    2011-01-01

    Sterilization by ionizing radiation is a technique used for tissue banks around the world to avoid transmission of infectious diseases by human allografts. However, high doses of ionizing radiation may cause undesirable changes in tissue structure, decreasing its mechanical properties, for example. Optical Coherence Tomography (OCT) is a non destructive, non ionizing and real time method to investigate biological tissues without promote any change in tissue structure. Polarization Sensitive Optical Coherence Tomography (PS-OCT) is an OCT technique that combines polarimetry with low coherence reflectometry to provide depth resolved measurements from birefringent structures as collagen. Costal cartilages from 15 cadaveric donors were preserved in high concentration glycerol and each individual sample was divided in 6 fragments. One of them was kept as a control group and the others were irradiated with gamma radiation from a Co-60 source with doses of 15, 25, 50, 75 and 100 kGy. OCT and PS-OCT images of the same region of the samples were obtained from a device OCS 1300 SS (Thorlabs, USA) with a coupling polarization module PSOCT 1300 (Thorlabs, USA). According with our results, birefringence may be visualized in all test groups as well in the control group, suggesting that sterilization by ionizing radiation does not affect the collagen structure significantly to cause total loss of birefringence, even if high doses as 75 and 100 kGy are used. The next step of our work is to develop a new method to quantify the birefringence using the optical properties of the tissue. (author)

  18. Imaging of irradiated human costal cartilage birefringence by PS-OCT

    Energy Technology Data Exchange (ETDEWEB)

    Martinho Junior, Antonio C.; Freitas, Anderson Z.; Santin, Stefany P.; Soares, Fernando A.N.; Mosca, Rodrigo C.; Bringel, Fabiana A.; Mathor, Monica B., E-mail: freitas.az@ipen.b, E-mail: rmosca@usp.b, E-mail: mathor@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Sterilization by ionizing radiation is a technique used for tissue banks around the world to avoid transmission of infectious diseases by human allografts. However, high doses of ionizing radiation may cause undesirable changes in tissue structure, decreasing its mechanical properties, for example. Optical Coherence Tomography (OCT) is a non destructive, non ionizing and real time method to investigate biological tissues without promote any change in tissue structure. Polarization Sensitive Optical Coherence Tomography (PS-OCT) is an OCT technique that combines polarimetry with low coherence reflectometry to provide depth resolved measurements from birefringent structures as collagen. Costal cartilages from 15 cadaveric donors were preserved in high concentration glycerol and each individual sample was divided in 6 fragments. One of them was kept as a control group and the others were irradiated with gamma radiation from a Co-60 source with doses of 15, 25, 50, 75 and 100 kGy. OCT and PS-OCT images of the same region of the samples were obtained from a device OCS 1300 SS (Thorlabs, USA) with a coupling polarization module PSOCT 1300 (Thorlabs, USA). According with our results, birefringence may be visualized in all test groups as well in the control group, suggesting that sterilization by ionizing radiation does not affect the collagen structure significantly to cause total loss of birefringence, even if high doses as 75 and 100 kGy are used. The next step of our work is to develop a new method to quantify the birefringence using the optical properties of the tissue. (author)

  19. Advancements in the Interferometric Measurements of Real Time Finishing Birefringent Filter's Crystal Plates

    International Nuclear Information System (INIS)

    Gan, Ma; Kushtal, Gi; Skomorovsky, Vi; Domyshev, Gn; Sadokhin, Vp

    2006-01-01

    The finishing of birefringent plates consists of two processes: polishing and evaluation of a surface, which have been performed separately till now. The purpose of this work is achieving of high accuracy of the evaluation and machining of the plane-parallel plates from birefringent crystals, in particular of crystal plates of birefringent filters during their finishing. The developed process combines evaluation and polishing in an interactive way. We have found modes of treatment, shape of polisher, have designed interferometer, with a mirror arranged in polisher. Visual checking of optical thickness comparatively with reference plate was carried out using the interference fringes of equal birefringence, and checking of an optical wedge - by interference rings of an equal inclination. The automated processing of TV camera interference fringes was impossible, because of gaps of interference fringes on polishing cells above the mirror. Therefore a special software was developed for processing of a complex fringe pattern interferogram. Software FastInterf uses furrier analysis technique which allows to process an interferogram with multiply gaps. Interferograms are registered by a high resolution TV camera (1280 x1024). Automatic processing of a fringe interferogram using FastInterf software takes less then one second. The influence of gaps is excluded, and the flat field is taken into account. Software provides full 3D surface and wavefront maps. Aberration analysis of a wavefront gives information on thickness of a plate comparatively with a reference one, optical wedge of plate and azimuth of an inclination of wave front. Moreover, software provides a control of surface quality. The measuring device, features of the software are described and process of interferometric evaluation during polishing is illustrated

  20. Advancements in the Interferometric Measurements of Real Time Finishing Birefringent Filter's Crystal Plates

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Ma [State Optical Institute, Birzhevaya linia, 12 St. Petersburg (Russian Federation); Kushtal, Gi; Skomorovsky, Vi; Domyshev, Gn; Sadokhin, Vp [Institute of Solar-Terrestrial Physics Siberian Branch of Russian Academy of Sciences, 126 Lermontova Str., PO 4026, 664033, Irkutsk (Russian Federation)

    2006-10-15

    The finishing of birefringent plates consists of two processes: polishing and evaluation of a surface, which have been performed separately till now. The purpose of this work is achieving of high accuracy of the evaluation and machining of the plane-parallel plates from birefringent crystals, in particular of crystal plates of birefringent filters during their finishing. The developed process combines evaluation and polishing in an interactive way. We have found modes of treatment, shape of polisher, have designed interferometer, with a mirror arranged in polisher. Visual checking of optical thickness comparatively with reference plate was carried out using the interference fringes of equal birefringence, and checking of an optical wedge - by interference rings of an equal inclination. The automated processing of TV camera interference fringes was impossible, because of gaps of interference fringes on polishing cells above the mirror. Therefore a special software was developed for processing of a complex fringe pattern interferogram. Software FastInterf uses furrier analysis technique which allows to process an interferogram with multiply gaps. Interferograms are registered by a high resolution TV camera (1280 x1024). Automatic processing of a fringe interferogram using FastInterf software takes less then one second. The influence of gaps is excluded, and the flat field is taken into account. Software provides full 3D surface and wavefront maps. Aberration analysis of a wavefront gives information on thickness of a plate comparatively with a reference one, optical wedge of plate and azimuth of an inclination of wave front. Moreover, software provides a control of surface quality. The measuring device, features of the software are described and process of interferometric evaluation during polishing is illustrated.

  1. Inverse thermoreversible mechanical stiffening and birefringence in methylcellulose/cellulose nanocrystal hydrogel.

    Science.gov (United States)

    Hynninen, Ville; Hietala, Sami; McKee, Jason Robert; Murtomäki, Lasse; Rojas, Orlando J; Ikkala, Olli; Nonappa, Nonappa

    2018-05-07

    We show that composite hydrogels comprising methyl cellulose (MC) and cellulose nanocrystal (CNC) colloidal rods display a reversible and enhanced rheological storage modulus and optical birefringence upon heating, i.e., inverse thermoreversibility. Dynamic rheology, quantitative polarized optical microscopy (POM), isothermal titration calorimetry (ITC), circular dichroism (CD), and scanning and transmission electron microscopy (SEM and TEM) were used for characterization. The concentration of CNC in aqueous media was varied up to 3.5 wt % (i.e, keeping the concentration below the critical aq. concentration) while maintaining the MC aq. concentration at 1.0 wt %. At 20 °C, MC/CNC underwent gelation upon passing the CNC concentration of 1.5 wt %. At this point the storage modulus (G´) reached a plateau, and the birefringence underwent a stepwise increase, thus suggesting a percolative phenomenon. The storage modulus (G´) of the composite gels was an order of magnitude higher at 60 °C compared to that at 20 °C. ITC results suggested that at 60 °C, the CNC rods were entropically driven to interact with MC chains, which according to recent studies, collapse at this temperature into ring-like, colloidal-scale persistent fibrils with hollow cross-section. Consequently, the increased requirement for space and mutual alignment of components results in enhanced birefringence. At room temperature, ITC shows enthalpic binding between CNCs and MC with the latter comprising an aqueous, molecularly dispersed polymer chains that lead to looser and less birefringent material. TEM, SEM, and CD indicated CNC chiral fragments within MC/CNC composite gel. Thus, their space-filling, thermoreversible assembly within the MC network can be used to tune the rheological properties and to access liquid crystalline properties at low CNC concentrations.

  2. Calculation of the mean differential group delay of periodically spun, randomly birefringent fibers

    Science.gov (United States)

    Galtarossa, Andrea; Griggio, Paola; Pizzinat, Anna; Palmieri, Luca

    2002-05-01

    Spinning is one of the most effective and well-known ways to reduce polarization mode dispersion of optical fibers. In spite of the popularity of spinning, a detailed theory of spin effects is still lacking. We report an analytical expression for the mean differential group delay of a randomly birefringent spun fiber. The result holds for any periodic spin function with a period shorter than the fiber's beat length.

  3. Competition of Faraday rotation and birefringence in femtosecond laser direct written waveguides in magneto-optical glass.

    Science.gov (United States)

    Liu, Qiang; Gross, S; Dekker, P; Withford, M J; Steel, M J

    2014-11-17

    We consider the process of Faraday rotation in femtosecond laser direct-write waveguides. The birefringence commonly associated with such waveguides may be expected to impact the observable Faraday rotation. Here, we theoretically calculate and experimentally verify the competition between Faraday rotation and birefringence in two waveguides created by laser writing in a commercial magneto-optic glass. The magnetic field applied to induce Faraday rotation is nonuniform, and as a result, we find that the two effects can be clearly separated and used to accurately determine even weak birefringence. The birefringence in the waveguides was determined to be on the scale of Δn = 10(-6) to 10(-5). The reduction in Faraday rotation caused by birefringence of order Δn = 10(-6) was moderate and we obtained approximately 9° rotation in an 11 mm waveguide. In contrast, for birefringence of order 10(-5), a significant reduction in the polarization azimuth change was found and only 6° rotation was observed.

  4. X-ray Birefringence: A New Strategy for Determining Molecular Orientation in Materials.

    Science.gov (United States)

    Palmer, Benjamin A; Edwards-Gau, Gregory R; Morte-Ródenas, Anabel; Kariuki, Benson M; Lim, Gin Keat; Harris, Kenneth D M; Dolbnya, Igor P; Collins, Stephen P

    2012-11-01

    While the phenomenon of birefringence is well-established in the case of visible radiation and is exploited in many fields (e.g., through the use of the polarizing optical microscope), the analogous phenomenon for X-rays has been a virtually neglected topic. Here, we demonstrate the scope and potential for exploiting X-ray birefringence to determine the orientational properties of specific types of bonds in solids. Specifically, orientational characteristics of C-Br bonds in the bromocyclohexane/thiourea inclusion compound are elucidated from X-ray birefringence measurements at energies close to the bromine K-edge, revealing inter alia the changes in the orientational distribution of the C-Br bonds associated with a low-temperature order-disorder phase transition. From fitting a theoretical model to the experimental data, reliable quantitative information on the orientational properties of the C-Br bonds is determined. The experimental strategy reported here represents the basis of a new approach for gaining insights into the orientational properties of molecules in anisotropic materials.

  5. The interplay between viscoelastic and thermodynamic properties determines the birefringence of F-actin gels.

    Science.gov (United States)

    Helfer, Emmanuèle; Panine, Pierre; Carlier, Marie-France; Davidson, Patrick

    2005-07-01

    F-actin gels of increasing concentrations (25-300 microM) display in vitro a progressive onset of birefringence due to orientational ordering of actin filaments. At F-actin concentrations mechanical stresses stored in the gels. In contrast, at F-actin concentrations > or =100 microM, gels display spontaneous birefringence recovery, at rest, which is the sign of true nematic ordering, in good agreement with statistical physics models of the isotropic/nematic transition. Well-aligned samples of F-actin gels could be produced and their small-angle x-ray scattering patterns are quite anisotropic. These patterns show no sign of filament positional short-range order and could be modeled by averaging the form factor with the Maier-Saupe nematic distribution function. The derived nematic order parameter S of the gels ranged from S = 0.7 at 300 microM to S = 0.4 at 25 microM. Both birefringence and small-angle x-ray scattering data indicate that, even in absence of cross-linking proteins, spontaneous cooperative alignment of actin filaments may arise in motile regions of living cells where F-actin concentrations can reach values of a few 100 microM.

  6. Characteristics of Highly Birefringent Photonic Crystal Fiber with Defected Core and Equilateral Pentagon Architecture

    Directory of Open Access Journals (Sweden)

    Fei Yu

    2016-01-01

    Full Text Available A novel high birefringence and nearly zero dispersion-flattened photonic crystal fiber (PCF with elliptical defected core (E-DC and equilateral pentagonal architecture is designed. By applying the full-vector finite element method (FEM, the characteristics of electric field distribution, birefringence, and chromatic dispersion of the proposed E-DC PCF are numerically investigated in detail. The simulation results reveal that the proposed PCF can realize high birefringence, ranging from 10-3 to 10-2 orders of magnitude, owing to the embedded elliptical air hole in the core center. However, the existence of the elliptical air hole gives rise to an extraordinary electric field distribution, where a V-shaped notch appears and the size of the V-shaped notch varies at different operating wavelengths. Also, the mode field diameter is estimated to be about 2 μm, which implies the small effective mode area and highly nonlinear coefficient. Furthermore, the investigation of the chromatic dispersion characteristic shows that the introduction of the elliptical air hole is helpful to control the chromatic dispersion to be negative or nearly zero flattened over a wide wavelength bandwidth.

  7. A bifunctional amorphous polymer exhibiting equal linear and circular photoinduced birefringences.

    Science.gov (United States)

    Royes, Jorge; Provenzano, Clementina; Pagliusi, Pasquale; Tejedor, Rosa M; Piñol, Milagros; Oriol, Luis

    2014-11-01

    The large and reversible photoinduced linear and circular birefringences in azo-compounds are at the basis of the interest in these materials, which are potentially useful for several applications. Since the onset of the linear and circular anisotropies relies on orientational processes, which typically occur on the molecular and supramolecular length scale, respectively, a circular birefringence at least one order of magnitude lower than the linear one is usually observed. Here, the synthesis and characterization of an amorphous polymer with a dimeric repeating unit containing a cyanoazobenzene and a cyanobiphenyl moiety are reported, in which identical optical linear and circular birefringences are induced for proper light dose and ellipticity. A pump-probe technique and an analytical method based on the Stokes-Mueller formalism are used to investigate the photoinduced effects and to evaluate the anisotropies. The peculiar photoresponse of the polymer makes it a good candidate for applications in smart functional devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Birefringence induced by pp-wave modes in an electromagnetically active dynamic aether

    International Nuclear Information System (INIS)

    Alpin, Timur Yu.; Balakin, Alexander B.

    2017-01-01

    In the framework of the Einstein-Maxwell-aether theory we study the birefringence effect, which can occur in the pp-wave symmetric dynamic aether. The dynamic aether is considered to be a latently birefringent quasi-medium, which displays this hidden property if and only if the aether motion is non-uniform, i.e., when the aether flow is characterized by the non-vanishing expansion, shear, vorticity or acceleration. In accordance with the dynamo-optical scheme of description of the interaction between electromagnetic waves and the dynamic aether, we shall model the susceptibility tensors by the terms linear in the covariant derivative of the aether velocity four-vector. When the pp-wave modes appear in the dynamic aether, we deal with a gravitationally induced degeneracy removal with respect to hidden susceptibility parameters. As a consequence, the phase velocities of electromagnetic waves possessing orthogonal polarizations do not coincide, thus displaying the birefringence effect. Two electromagnetic field configurations are studied in detail: longitudinal and transversal with respect to the aether pp-wave front. For both cases the solutions are found, which reveal anomalies in the electromagnetic response on the action of the pp-wave aether mode. (orig.)

  9. Birefringence induced by pp-wave modes in an electromagnetically active dynamic aether

    Energy Technology Data Exchange (ETDEWEB)

    Alpin, Timur Yu.; Balakin, Alexander B. [Kazan Federal University, Department of General Relativity and Gravitation, Institute of Physics, Kazan (Russian Federation)

    2017-10-15

    In the framework of the Einstein-Maxwell-aether theory we study the birefringence effect, which can occur in the pp-wave symmetric dynamic aether. The dynamic aether is considered to be a latently birefringent quasi-medium, which displays this hidden property if and only if the aether motion is non-uniform, i.e., when the aether flow is characterized by the non-vanishing expansion, shear, vorticity or acceleration. In accordance with the dynamo-optical scheme of description of the interaction between electromagnetic waves and the dynamic aether, we shall model the susceptibility tensors by the terms linear in the covariant derivative of the aether velocity four-vector. When the pp-wave modes appear in the dynamic aether, we deal with a gravitationally induced degeneracy removal with respect to hidden susceptibility parameters. As a consequence, the phase velocities of electromagnetic waves possessing orthogonal polarizations do not coincide, thus displaying the birefringence effect. Two electromagnetic field configurations are studied in detail: longitudinal and transversal with respect to the aether pp-wave front. For both cases the solutions are found, which reveal anomalies in the electromagnetic response on the action of the pp-wave aether mode. (orig.)

  10. STRUCTURAL PROPERTIES OF NON-SPHERICAL DARK HALOS IN MILKY WAY AND ANDROMEDA DWARF SPHEROIDAL GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Kohei [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo, Chiba 277-8583 (Japan); Chiba, Masashi, E-mail: kohei.hayashi@ipmu.jp, E-mail: chiba@astr.tohoku.ac.jp [Astronomical Institute, Tohoku University, Aoba-ku, Sendai 980-8578 (Japan)

    2015-09-01

    We investigate the non-spherical density structure of dark halos of the dwarf spheroidal (dSph) galaxies in the Milky Way and Andromeda galaxies based on revised axisymmetric mass models from our previous work. The models we adopt here fully take into account velocity anisotropy of tracer stars confined within a flattened dark halo. Applying our models to the available kinematic data of the 12 bright dSphs, we find that these galaxies associate with, in general, elongated dark halos, even considering the effect of this velocity anisotropy of stars. We also find that the best-fit parameters, especially for the shapes of dark halos and velocity anisotropy, are susceptible to both the availability of velocity data in the outer regions and the effect of the lack of sample stars in each spatial bin. Thus, to obtain more realistic limits on dark halo structures, we require photometric and kinematic data over much larger areas in the dSphs than previously explored. The results obtained from the currently available data suggest that the shapes of dark halos in the dSphs are more elongated than those of ΛCDM subhalos. This mismatch needs to be solved by theory including baryon components and the associated feedback to dark halos as well as by further observational limits in larger areas of dSphs. It is also found that more diffuse dark halos may have undergone consecutive star formation history, thereby implying that dark-halo structure plays an important role in star formation activity.

  11. Examination of Effective Dielectric Constants Derived from Non-Spherical Melting Hydrometeor

    Science.gov (United States)

    Liao, L.; Meneghini, R.

    2009-04-01

    The bright band, a layer of enhanced radar echo associated with melting hydrometeors, is often observed in stratiform rain. Understanding the microphysical properties of melting hydrometeors and their scattering and propagation effects is of great importance in accurately estimating parameters of the precipitation from spaceborne radar and radiometers. However, one of the impediments in the study of the radar signature of the melting layer is the determination of effective dielectric constants of melting hydrometeors. Although a number of mixing formulas are available to compute the effective dielectric constants, their results vary to a great extent when water is a component of the mixture, such as in the case of melting snow. It is also physically unclear as to how to select among these various formulas. Furthermore, the question remains as to whether these mixing formulas can be applied to computations of radar polarimetric parameters from non-spherical melting particles. Recently, several approaches using numerical methods have been developed to derive the effective dielectric constants of melting hydrometeors, i.e., mixtures consisting of air, ice and water, based on more realistic melting models of particles, in which the composition of the melting hydrometeor is divided into a number of identical cells. Each of these cells is then assigned in a probabilistic way to be water, ice or air according to the distribution of fractional water contents for a particular particle. While the derived effective dielectric constants have been extensively tested at various wavelengths over a range of particle sizes, these numerical experiments have been restricted to the co-polarized scattering parameters from spherical particles. As polarimetric radar has been increasingly used in the study of microphysical properties of hydrometeors, an extension of the theory to polarimetric variables should provide additional information on melting processes. To account for polarimetric

  12. Optical trapping of colloidal particles and measurement of the defect line tension and colloidal forces in a thermotropic nematic liquid crystal

    International Nuclear Information System (INIS)

    Smalyukh, I.I.; Kuzmin, A.N.; Kachynski, A.V.; Prasad, P.N.; Lavrentovich, O.D.

    2005-01-01

    We demonstrate optical trapping and manipulation of transparent microparticles suspended in a thermotropic nematic liquid crystal with low birefringence. We employ the particle manipulation to measure line tension of a topologically stable disclination line and to determine colloidal interaction of particles with perpendicular surface anchoring of the director. The three-dimensional director fields and positions of the particles manipulated by laser tweezers are visualized by fluorescence confocal polarizing microscopy

  13. Ion Trap Quantum Computing

    Science.gov (United States)

    2011-12-01

    variations of ion traps, including (1) the cylindrically symmetric 3D ring trap; (2) the linear trap with a combination of cavity QED; (#) the symmetric...concepts of quantum information. The major demonstration has been the test of a Bell inequality as demonstrated by Rowe et al. [50] and a decoherence...famous physics experiment [62]. Wolfgang Paul demonstrated a similar apparatus during his Nobel Prize speech [63]. This device is hyperbolic- parabolic

  14. Optical properties of non-spherical desert dust particles in the terrestrial infrared – An asymptotic approximation approach

    International Nuclear Information System (INIS)

    Klüser, Lars; Di Biagio, Claudia; Kleiber, Paul D.; Formenti, Paola; Grassian, Vicki H.

    2016-01-01

    Optical properties (extinction efficiency, single scattering albedo, asymmetry parameter and scattering phase function) of five different desert dust minerals have been calculated with an asymptotic approximation approach (AAA) for non-spherical particles. The AAA method combines Rayleigh-limit approximations with an asymptotic geometric optics solution in a simple and straightforward formulation. The simulated extinction spectra have been compared with classical Lorenz–Mie calculations as well as with laboratory measurements of dust extinction. This comparison has been done for single minerals and with bulk dust samples collected from desert environments. It is shown that the non-spherical asymptotic approximation improves the spectral extinction pattern, including position of the extinction peaks, compared to the Lorenz–Mie calculations for spherical particles. Squared correlation coefficients from the asymptotic approach range from 0.84 to 0.96 for the mineral components whereas the corresponding numbers for Lorenz–Mie simulations range from 0.54 to 0.85. Moreover the blue shift typically found in Lorenz–Mie results is not present in the AAA simulations. The comparison of spectra simulated with the AAA for different shape assumptions suggests that the differences mainly stem from the assumption of the particle shape and not from the formulation of the method itself. It has been shown that the choice of particle shape strongly impacts the quality of the simulations. Additionally, the comparison of simulated extinction spectra with bulk dust measurements indicates that within airborne dust the composition may be inhomogeneous over the range of dust particle sizes, making the calculation of reliable radiative properties of desert dust even more complex. - Highlights: • A fast and simple method for estimating optical properties of dust. • Can be used with non-spherical particles of arbitrary size distributions. • Comparison with Mie simulations and

  15. Towards trapped antihydrogen

    CERN Document Server

    Jorgensen, L V; Bertsche, W; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    Substantial progress has been made in the last few years in the nascent field of antihydrogen physics. The next big step forward is expected to be the trapping of the formed antihydrogen atoms using a magnetic multipole trap. ALPHA is a new international project that started to take data in 2006 at CERN’s Antiproton Decelerator facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms to facilitate measurements of its properties. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.

  16. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    International Nuclear Information System (INIS)

    Raposo, Maria; Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A.; Ferreira, Quirina; Botelho do Rego, Ana Maria

    2015-01-01

    Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior

  17. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    Energy Technology Data Exchange (ETDEWEB)

    Raposo, Maria, E-mail: mfr@fct.unl.pt; Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Ferreira, Quirina [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Instituto de Telecomunicações, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, P-1049-001 Lisboa (Portugal); Botelho do Rego, Ana Maria [Centro de Química-Física Molecular and IN, Complexo Interdisciplinar, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisboa (Portugal)

    2015-09-21

    Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior.

  18. Versatile electrostatic trap

    NARCIS (Netherlands)

    van Veldhoven, J.; Bethlem, H.L.; Schnell, M.; Meijer, G.

    2006-01-01

    A four electrode electrostatic trap geometry is demonstrated that can be used to combine a dipole, quadrupole, and hexapole field. A cold packet of ND315 molecules is confined in both a purely quadrupolar and hexapolar trapping field and additionally, a dipole field is added to a hexapole field to

  19. Liquid metal cold trap

    International Nuclear Information System (INIS)

    Hundal, R.

    1976-01-01

    A cold trap assembly for removing impurities from a liquid metal is described. A hole between the incoming impure liquid metal and purified outgoing liquid metal acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly

  20. Deuterium trapping in tungsten

    Science.gov (United States)

    Poon, Michael

    Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV. Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

  1. Deuterium trapping in tungsten

    International Nuclear Information System (INIS)

    Poon, M.

    2004-01-01

    Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. . Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D 2 molecules inside the void with a trap energy of 1.2 eV. . Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

  2. Deuterium trapping in tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Poon, M

    2004-07-01

    Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. . Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D{sub 2} molecules inside the void with a trap energy of 1.2 eV. . Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

  3. Trapping radioactive ions

    CERN Document Server

    Kluge, Heinz-Jürgen

    2004-01-01

    Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning.

  4. Trapping radioactive ions

    International Nuclear Information System (INIS)

    Kluge, H.-J.; Blaum, K.

    2004-01-01

    Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning

  5. Nonsphericity Index and Size Ratio Identify Morphologic Differences between Growing and Stable Aneurysms in a Longitudinal Study of 93 Cases.

    Science.gov (United States)

    Chien, A; Xu, M; Yokota, H; Scalzo, F; Morimoto, E; Salamon, N

    2018-01-25

    Recent studies have strongly associated intracranial aneurysm growth with increased risk of rupture. Identifying aneurysms that are likely to grow would be beneficial to plan more effective monitoring and intervention strategies. Our hypothesis is that for unruptured intracranial aneurysms of similar size, morphologic characteristics differ between aneurysms that continue to grow and those that do not. From aneurysms in our medical center with follow-up imaging dates in 2015, ninety-three intracranial aneurysms (23 growing, 70 stable) were selected. All CTA images for the aneurysm diagnosis and follow-up were collected, a total of 348 3D imaging studies. Aneurysm 3D geometry for each imaging study was reconstructed, and morphologic characteristics, including volume, surface area, nonsphericity index, aspect ratio, and size ratio were calculated. Morphologic characteristics were found to differ between growing and stable groups. For aneurysms of 7 mm, volume ( P differ between those that are growing and those that are stable. The nonsphericity index, in particular, was found to be higher among growing aneurysms. The size ratio was found to be the second most significant parameter associated with growth. © 2018 by American Journal of Neuroradiology.

  6. Application of Convolution Perfectly Matched Layer in MRTD scattering model for non-spherical aerosol particles and its performance analysis

    Science.gov (United States)

    Hu, Shuai; Gao, Taichang; Li, Hao; Yang, Bo; Jiang, Zidong; Liu, Lei; Chen, Ming

    2017-10-01

    The performance of absorbing boundary condition (ABC) is an important factor influencing the simulation accuracy of MRTD (Multi-Resolution Time-Domain) scattering model for non-spherical aerosol particles. To this end, the Convolution Perfectly Matched Layer (CPML), an excellent ABC in FDTD scheme, is generalized and applied to the MRTD scattering model developed by our team. In this model, the time domain is discretized by exponential differential scheme, and the discretization of space domain is implemented by Galerkin principle. To evaluate the performance of CPML, its simulation results are compared with those of BPML (Berenger's Perfectly Matched Layer) and ADE-PML (Perfectly Matched Layer with Auxiliary Differential Equation) for spherical and non-spherical particles, and their simulation errors are analyzed as well. The simulation results show that, for scattering phase matrices, the performance of CPML is better than that of BPML; the computational accuracy of CPML is comparable to that of ADE-PML on the whole, but at scattering angles where phase matrix elements fluctuate sharply, the performance of CPML is slightly better than that of ADE-PML. After orientation averaging process, the differences among the results of different ABCs are reduced to some extent. It also can be found that ABCs have a much weaker influence on integral scattering parameters (such as extinction and absorption efficiencies) than scattering phase matrices, this phenomenon can be explained by the error averaging process in the numerical volume integration.

  7. Linear Transformation of the Polarization Modes in Coiled Optical Spun-Fibers with Strong Unperturbed Linear Birefringence. I. Nonresonant Transformation

    Science.gov (United States)

    Malykin, G. B.; Pozdnyakova, V. I.

    2018-03-01

    A linear transformation of orthogonal polarization modes in coiled optical spun-fibers with strong unperturbed linear birefringence, which causes the emergence of the dependences of the integrated elliptical birefringence and the ellipticity and azimuth of the major axis of the ellipse, as well as the polarization state of radiation (PSR), on the length of optical fiber has been considered. Optical spun-fibers are subjected to a strong mechanical twisting, which is frozen into the structure of the optical fiber upon cooling, in the process of being drawn out from the workpiece. Since the values of the local polarization parameters of coiled spunwaveguides vary according to a rather complex law, the calculations were carried out by numerical modeling of the parameters of the Jones matrices. Since the rotation speed of the axes of the birefringence is constant on a relatively short segment of a coiled optical spun-fiber in the accompanying torsion (helical) coordinate system, the so-called "Ginzburg helical polarization modes" (GHPMs)—two mutually orthogonal ellipses with the opposite directions of traversal, the axis of which rotate relative to the fixed coordinate system uniformly and unidirectionally—are approximately the local normal polarization modes of such optical fiber. It has been shown that, despite the fact that the unperturbed linear birefringence of the spun-fibers significantly exceeds the linear birefringence, which is caused by the winding on a coil, the integral birefringence of an extended segment of such a fiber coincides in order of magnitude with the linear birefringence, which is caused by the winding on the coil, and the integral polarization modes tend asymptotically to circular ones. It has been also shown that the values of the circular birefringence of twisted single-mode fibers, which were calculated in a nonrotating and torsion helical coordinate systems, differ significantly. It has been shown that the polarization phenomena occur

  8. BRAGG GRATINGS MULTIPUSLE INSCRIPTION EFFICIENCY DEPENDENCE ON ANGULAR POSITION OF ELLIPTICAL STRESS CLADDING IN BIREFRINGENT OPTICAL FIBERS

    Directory of Open Access Journals (Sweden)

    Sergey V. Arkhipov

    2017-09-01

    Full Text Available Subject of Research.The paper deals with mutlipulse inscription comparative results of the type IBragg gratings in the birefringent optical fiber with elliptical stress cladding and increased GeO2 concentration at different birefringence axes positions. Method. The gratings were inscribed by the phase mask method. The excimer laser Coherent COMPexPro 102F, working with the gas mixture KrF (248 nm, was used as the radiation source. The phase mask Ibsen Photonics with a period of1065.3 nm was used. Main Results.The results have shown that the multipusle inscription is more effective and has better dynamics when the plane containing the fiber axis and its slow birefringence axis is parallel to the writing radiation incidence plane containing the fiber axis. Practical Relevance. The research results give the possibility to make recommendations for the multipulse Bragg gratings inscription efficiency enhancement in the specialty birefringent fibers. The preinscription positioning of birefringence axes also makes it possible to reduce the polarization fading that is the noise source in phase interferometric sensors.

  9. STUDY OF BIREFRINGENCE INFLUENCE ON IMAGE QUALITY OF PHOTOLITHOGRAPHY SYSTEMS IN VIEW OF PARTIALLY-COHERENT LIGHT SOURCE

    Directory of Open Access Journals (Sweden)

    E. A. Nikulina

    2015-03-01

    Full Text Available Subject of study. A vector model for conversion of electromagnetic radiation in optical systems is considered, taking into account the influence of birefringence, as well as partially coherent illumination. Model. The proposed model is based on the representation of the complex amplitude of the monochromatic field through thesuperposition of basic plane waves. Transmitted light image with partially coherent illumination is performed by the sourceintegration method. Main results. The results of simulation for the point spread function are demonstrating the level of the birefringence influence on the image quality. In the presence of the wave aberration about 0.098 of the wavelength, the wave energy loss in the center of the Airy disk with an average birefringence of 4 nm/cm was 8%, and at 16 nm/cm it reached 30%. The calculation of the point spread function for a real sample of fluorite is given. The central peak of the PSF without birefringence was 0.722, with regard to birefringence it was equal to 0.701. Practical significance. The findings can be used in the development of photolithographic lenses, as well as for the manufacturing of any other optical systems that require consideration of the polarization properties of the materials.

  10. Novel technique for spatially resolved imaging of molecular bond orientations using x-ray birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, John P., E-mail: john.sutter@diamond.ac.uk; Dolbnya, Igor P.; Collins, Stephen P. [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Harris, Kenneth D. M., E-mail: HarrisKDM@cardiff.ac.uk; Edwards-Gau, Gregory R.; Kariuki, Benson M. [School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT (United Kingdom); Palmer, Benjamin A. [Department of Structural Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001 (Israel)

    2016-07-27

    Birefringence has been observed in anisotropic materials transmitting linearly polarized X-ray beams tuned close to an absorption edge of a specific element in the material. Synchrotron bending magnets provide X-ray beams of sufficiently high brightness and cross section for spatially resolved measurements of birefringence. The recently developed X-ray Birefringence Imaging (XBI) technique has been successfully applied for the first time using the versatile test beamline B16 at Diamond Light Source. Orientational distributions of the C–Br bonds of brominated “guest” molecules within crystalline “host” tunnel structures (in thiourea or urea inclusion compounds) have been studied using linearly polarized incident X-rays near the Br K-edge. Imaging of domain structures, changes in C–Br bond orientations associated with order-disorder phase transitions, and the effects of dynamic averaging of C–Br bond orientations have been demonstrated. The XBI setup uses a vertically deflecting high-resolution double-crystal monochromator upstream from the sample and a horizontally deflecting single-crystal polarization analyzer downstream, with a Bragg angle as close as possible to 45°. In this way, the ellipticity and rotation angle of the polarization of the beam transmitted through the sample is measured as in polarizing optical microscopy. The theoretical instrumental background calculated from the elliptical polarization of the bending-magnet X-rays, the imperfect polarization discrimination of the analyzer, and the correlation between vertical position and photon energy introduced by the monochromator agrees well with experimental observations. The background is calculated analytically because the region of X-ray phase space selected by this setup is sampled inefficiently by standard methods.

  11. Nematode-Trapping Fungi.

    Science.gov (United States)

    Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

    2017-01-01

    Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.

  12. Simultaneous measurement of dynamic strain and temperature distribution using high birefringence PANDA fiber Bragg grating

    Science.gov (United States)

    Zhu, Mengshi; Murayama, Hideaki

    2017-04-01

    New approach in simultaneous measurement of dynamic strain and temperature has been done by using a high birefringence PANDA fiber Bragg grating sensor. By this technique, we have succeeded in discriminating dynamic strain and temperature distribution at the sampling rate of 800 Hz and the spatial resolution of 1 mm. The dynamic distribution of strain and temperature were measured with the deviation of 5mm spatially. In addition, we have designed an experimental setup by which we can apply quantitative dynamic strain and temperature distribution to the fiber under testing without bounding it to a specimen.

  13. Pump Spectral Bandwidth, Birefringence, and Entanglement in Type-II Parametric Down Conversion

    Directory of Open Access Journals (Sweden)

    Daniel Erenso

    2009-01-01

    Full Text Available The twin photons produced by a type-II spontaneous parametric down conversion are well know as a potential source of photons for quantum teleportation due to the strong entanglement in polarization. This strong entanglement in polarization, however, depends on the spectral composition of the pump photon and the nature of optical isotropy of the crystal. By exact numerical calculation of the concurrence, we have shown that how pump photons spectral width and the birefringence nature of the crystal directly affect the degree of polarization entanglement of the twin photons.

  14. Design of infrared imaging birefringent interferometers for small-UAVs and handheld scanning systems (Conference Presentation)

    Science.gov (United States)

    Pola Fossi, Armande; Ferrec, Yann; Guerineau, Nicolas; Roux, Nicolas; Kling, Emmanuel; Sauer, Hervé

    2016-10-01

    Hyperspectral imaging from unmanned aerial vehicles arouses a growing interest, as well for agriculture management as pollution monitoring or security purposes. Most of current instruments are in the visible or near infrared spectral range, but the midwave or longwave infrared may also be interesting. Among the available solutions for compact imaging spectrometers in this spectral range, static imaging Fourier transform spectrometers are well adapted, thanks to the absence of moving part, a 2D snapshot imaging, which can be useful for image registration, and a high flux collection efficiency. To reach a high compactness compliant with small UAVs, birefringent interferometers are good candidates. Indeed, they can be roughly seen as a plate which comes in front of the camera lens. We propose here firstly to expose the design rules of such instruments in the midwave or longwave infrared. The first point is about the material: highly birefringent uniaxial crystals materials are not so common in this spectral domain. For MWIR spectral imagers, TeO2 or YVO4 can be used. For LWIR instruments, current materials, like ZnGeP2 or AgGaS2 are available, but their birefringence is not so high. Calomel is a promising way, but not still available. The second point consists in defining the type of interferometer, like Savart interferometer, Wollaston interferometer, or other designs. To help this choice, we have developed a software tool to calculate the propagation of plane waves in a stack of birefringent plates. This allows us to choose the optimal assembly of the plates to reach the required spectral resolution. We will then present experimental results obtained with a MWIR prototype. This prototype, called SIBI,, works in the [3.7µm-4.8µm] spectral domain (or [2050cm 1-2700cm 1]), with a spectral resolution about 13cm 1. A first ground campaign was led in June 2015, on Mount Etna (Italy). This campaign was useful to emphasize the assets and drawbacks of this instrument

  15. Enhanced performance of semiconductor optical amplifier at high direct modulation speed with birefringent fiber loop

    Directory of Open Access Journals (Sweden)

    K. E. Zoiros

    2014-07-01

    Full Text Available We employ a birefringent fiber loop (BFL for enhancing the performance of a semiconductor optical amplifier (SOA which is directly modulated. By properly exploiting the BFL comb-like spectral response, we show that the SOA can be directly modulated at a data rate which is more than five times faster than that enabled by the SOA electrical bandwidth. The experimental results, which include chirp measurements, demonstrate the significant improvements achieved in the performance of the directly modulated SOA with the help of the BFL.

  16. Reversible change of birefringence sign by optical and thermal processes in an azobenzene polymethacrylate

    International Nuclear Information System (INIS)

    Rodriguez, F.J.; Sanchez, C.; Villacampa, B.; Alcala, R.; Cases, R.; Millaruelo, M.; Oriol, L.

    2005-01-01

    Birefringence (Δn) induced in an azobenzene polymethacrylate by combination of biphotonic and thermotropic processes has subsequently been changed in sign by room temperature illumination with linearly polarized blue light. The sign of Δn can be reversed again, by simply heating up the film to 100 deg. C. This change of Δn between positive and negative values can be repeated several times. Besides, by appropriate choice of film thickness and blue light irradiation conditions the same absolute value for positive and negative Δn values can be obtained

  17. Design of low-loss and highly birefringent hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Roberts, Peter John; Williams, D.P.; Sabert, H.

    2006-01-01

    A practical hollow-core photonic crystal fiber design suitable for attaining low-loss propagation is analyzed. The geometry involves a number of localized elliptical features positioned on the glass ring that surrounds the air core and separates the core and cladding regions. The size of each...... feature is tuned so that the composite core-surround geometry is antiresonant within the cladding band gap, thus minimizing the guided mode field intensity both within the fiber material and at material / air interfaces. A birefringent design, which involves a 2-fold symmetric arrangement of the features...

  18. Repeating pulsed magnet system for axion-like particle searches and vacuum birefringence experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, T., E-mail: yamazaki@icepp.s.u-tokyo.ac.jp [International Center for Elementary Particle Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Inada, T.; Namba, T. [International Center for Elementary Particle Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Asai, S. [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kobayashi, T. [International Center for Elementary Particle Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Matsuo, A.; Kindo, K. [The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8581 (Japan); Nojiri, H. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2016-10-11

    We have developed a repeating pulsed magnet system which generates magnetic fields of about 10 T in a direction transverse to an incident beam over a length of 0.8 m with a repetition rate of 0.2 Hz. Its repetition rate is by two orders of magnitude higher than usual pulsed magnets. It is composed of four low resistance racetrack coils and a 30 kJ transportable capacitor bank as a power supply. The system aims at axion-like particle searches with a pulsed light source and vacuum birefringence measurements. We report on the details of the system and its performances.

  19. Photoinduced Birefringent Pattern and Photoinactivation of Liquid-Crystalline Copolymer Films with Benzoic Acid and Phenylaldehyde Side Groups.

    Science.gov (United States)

    Kawatsuki, Nobuhiro; Inada, Shogo; Fujii, Ryosuke; Kondo, Mizuho

    2018-02-06

    In situ formation of N-benzylideneaniline (NBA) side groups achieved photoinduced cooperative reorientation of photoinactive copolymers with phenylaldehyde (PA) and benzoic acid (BA) side groups doped with 4-methoxyaniline (AN) molecules. Thermally stimulated molecular reorientation of the side groups was generated due to the axis-selective photoreaction of the NBA moieties. Selective coating with AN on the copolymer film formed NBA moieties in the desired region, resulting in a photoinduced birefringent pattern. Additionally, postannealing at an elevated temperature for a long time attained photoinactivation of the reoriented film, and recoating with AN to form NBA achieved the multiple birefringent patterns and repatterning of the reoriented structures. The slow thermal hydrolysis of NBA, which was 50 times slower than the thermally stimulated self-organization of the side groups due to the presence of BA side groups, contributed to the photodurability of the reoriented film and multiple birefringent patterns.

  20. Further comments on the effects of vacuum birefringence on the polarization of X-rays emitted from magnetic neutron stars

    Science.gov (United States)

    Chanan, G. A.; Novick, R.; Silver, E. H.

    1979-01-01

    The birefringence of the vacuum in the presence of strong (of the order of 1 teragauss) magnetic fields will in general affect the polarization of X-rays propagating through these fields. Two of the four Stokes parameters will vary so rapidly with wavelength as to be 'washed out' and unobservable, but the remaining two parameters will be unaffected. These results show that one conclusion of an earlier work is incorrect: Polarized X-ray emission from the surface of a magnetic neutron star will not in general be completely depolarized by the effects of vacuum birefringence. In particular, this birefringence has no effect on the linear polarization of cyclotron emission from the poles of magnetic neutron stars, and a similar result holds for synchrotron emission. More general cases of the propagation of polarized X-rays in magnetic fields are also discussed.

  1. Non-spherical core collapse supernovae. III. Evolution towards homology and dependence on the numerical resolution

    Science.gov (United States)

    Gawryszczak, A.; Guzman, J.; Plewa, T.; Kifonidis, K.

    2010-10-01

    Aims: We study the hydrodynamic evolution of a non-spherical core-collapse supernova in two spatial dimensions. We begin our study from the moment of shock revival - taking into account neutrino heating and cooling, nucleosynthesis, convection, and the standing accretion shock (SASI) instability of the supernova blast - and continue for the first week after the explosion when the expanding flow becomes homologous and the ejecta enter the early supernova remnant (SNR) phase. We observe the growth and interaction of Richtmyer-Meshkov, Rayleigh-Taylor, and Kelvin-Helmholtz instabilities resulting in an extensive mixing of the heavy elements throughout the ejecta. We obtain a series of models at progressively higher resolution and provide a discussion of numerical convergence. Methods: Different from previous studies, our computations are performed in a single domain. Periodic mesh mapping is avoided. This is made possible by employing cylindrical coordinates, and an adaptive mesh refinement (AMR) strategy in which the computational workload (defined as the product of the total number of computational cells and the length of the time step) is monitored and, if necessary, reduced. Results: Our results are in overall good agreement with the AMR simulations we have reported in the past. We show, however, that numerical convergence is difficult to achieve, due to the strongly non-linear nature of the problem. Even more importantly, we find that our model displays a strong tendency to expand laterally away from the equatorial plane and toward the poles. We demonstrate that this expansion is a physical property of the low-mode, SASI instability. Although the SASI operates only within about the first second of the explosion, it leaves behind a large lateral velocity gradient in the post shock layer which affects the evolution for minutes and hours later. This results in a prolate deformation of the ejecta and a fast advection of the highest-velocity 56Ni-rich material from

  2. Trapping and Probing Antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Wurtele, Jonathan [UC Berkeley and LBNL

    2013-03-27

    Precision spectroscopy of antihydrogen is a promising path to sensitive tests of CPT symmetry. The most direct route to achieve this goal is to create and probe antihydrogen in a magnetic minimum trap. Antihydrogen has been synthesized and trapped for 1000s at CERN by the ALPHA Collaboration. Some of the challenges associated with achieving these milestones will be discussed, including mixing cryogenic positron and antiproton plasmas to synthesize antihydrogen with kinetic energy less than the trap potential of .5K. Recent experiments in which hyperfine transitions were resonantly induced with microwaves will be presented. The opportunity for gravitational measurements in traps based on detailed studies of antihydrogen dynamics will be described. The talk will conclude with a discussion future antihydrogen research that will use a new experimental apparatus, ALPHA-I.

  3. EBIT trapping program

    International Nuclear Information System (INIS)

    Elliott, S.R.; Beck, B.; Beiersdorfer, P.; Church, D.; DeWitt, D.; Knapp, D.K.; Marrs, R.E.; Schneider, D.; Schweikhard, L.

    1993-01-01

    The LLNL electron beam ion trap provides the world's only source of stationary highly charged ions up to bare U. This unique capability makes many new atomic and nuclear physics experiments possible. (orig.)

  4. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

  5. Birefringence dynamics of poly{1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt} cast films

    International Nuclear Information System (INIS)

    Madruga, Carla; Filho, Paulo Alliprandini; Andrade, Marta M.; Goncalves, Manuel; Raposo, Maria; Ribeiro, Paulo A.

    2011-01-01

    Photoinduced birefringence creation/decay dynamics in poly{1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt}cast films, has been characterized in the 5 to 100 mW writing laser power range at the wavelength of 514 nm. The maximum birefringence magnitude increased with laser beam power, being the largest value of 0.03, measured at 632.8 nm. Birefringence creation kinetics followed a biexponential behavior, where a slow process and a fast process could be clearly distinguished. The fast process accounted for more than 60% of birefringence. The time constants for both fast and slow processes decreased with increasing power of writing beam. Birefringence relaxation after removal of writing laser beam revealed to be independent of beam power and, was found to be ruled by two processes, described by a biexponential curve plus a constant term accounting for residual birefringence. A high residual birefringence signal of 85 ± 3% was attained, with the fast process contributing to 67% of decay from maximum value. The large values obtained for time constants for both birefringence creation and relaxation processes are believed to arise from stabilization of azo-group either by the formation of an ionic network, or by local short range interactions that are coming through as a result polyelectrolyte coiling due to its high degree of ionization.

  6. In vivo polarization-sensitive optical coherence tomography of human burn scars: birefringence quantification and correspondence with histologically determined collagen density

    Science.gov (United States)

    Jaspers, Mariëlle E. H.; Feroldi, Fabio; Vlig, Marcel; de Boer, Johannes F.; van Zuijlen, Paul P. M.

    2017-12-01

    Obtaining adequate information on scar characteristics is important for monitoring their evolution and the effectiveness of clinical treatment. The aberrant type of collagen in scars may give rise to specific birefringent properties, which can be determined using polarization-sensitive optical coherence tomography (PS-OCT). The aim of this pilot study was to evaluate a method to quantify the birefringence of the scanned volume and correlate it with the collagen density as measured from histological slides. Five human burn scars were measured in vivo using a handheld probe and custom-made PS-OCT system. The local retardation caused by the tissue birefringence was extracted using the Jones formalism. To compare the samples, histograms of birefringence values of each volume were produced. After imaging, punch biopsies were harvested from the scar area of interest and sent in for histological evaluation using Herovici polychrome staining. Two-dimensional en face maps showed higher birefringence in scars compared to healthy skin. The Pearson's correlation coefficient for the collagen density as measured by histology versus the measured birefringence was calculated at r=0.80 (p=0.105). In conclusion, the custom-made PS-OCT system was capable of in vivo imaging and quantifying the birefringence of human burn scars, and a nonsignificant correlation between PS-OCT birefringence and histological collagen density was found.

  7. Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses

    International Nuclear Information System (INIS)

    Amjad, Jafar Mostafavi; Khalesifard, Hamid Reza; Slussarenko, Sergei; Karimi, Ebrahim; Santamato, Enrico; Marrucci, Lorenzo

    2011-01-01

    Samples of Ag + /Na + ion-exchanged glass that have been subject to intense laser irradiation may develop novel optical properties, as a consequence of the formation of patterns of silver nanoparticles and other structures. Here, we report the observation of a laser-induced permanent transverse birefringence, with the optical axis forming a radial pattern, as revealed by the spin-to-orbital angular momentum conversion occurring in a probe light beam. The birefringence pattern can be modeled well as resulting from thermally-induced stresses arising in the silver-doped glass during laser exposure, although the actual mechanism leading to the permanent anisotropy is probably more complex.

  8. Phase-matched light amplification by three-wave mixing process in a birefringent fiber due to externally applied stress

    International Nuclear Information System (INIS)

    Ohashi, M.; Kitayama, K.; Ishida, Y.; Uchida, N.

    1982-01-01

    A novel method to achieve phase-matched light amplification in a birefringent fiber via the three-wave mixing is proposed by using frequency shift change due to the stress applied to the fiber. It is confirmed that the signal power from a cw laser diode at lambda = 1.292 μm is amplified by 6.1 x 10 3 times in the birefringent fiber pumped with a Q-switched Nd: yttrium aluminum garnet laser at lambda = 1.064 μm. This will provide a new fiber-optic light signal amplifier having a good tolerance for variation of signal wavelengths

  9. Detection of local birefringence in embedded fiber Bragg grating caused by concentrated transverse load using optical frequency domain reflectometry

    Science.gov (United States)

    Wada, D.; Murayama, H.; Igawa, H.

    2014-05-01

    We investigate the capability of local birefringence detection in an embedded fiber Bragg grating (FBG) using optical frequency domain reflectometry. We embed an FBG into carbon fiber reinforced plastic specimen, and conduct 3-point bending test. The cross-sectional stresses are applied to the FBG at the loading location in addition to the non-uniform longitudinal strain distribution over the length of the FBG. The local birefringence due to the cross-sectional stresses was successfully detected while the non-uniform longitudinal strain distribution was accurately measured.

  10. Search For Trapped Antihydrogen

    CERN Document Server

    Andresen, Gorm B.; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D.; Bray, Crystal C.; Butler, Eoin; Cesar, Claudio L.; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C.; Gill, David R.; Hangst, Jeffrey S.; Hardy, Walter N.; Hayano, Ryugo S.; Hayden, Michael E.; Humphries, Andrew J.; Hydomako, Richard; Jonsell, Svante; Jorgensen, Lars V.; Kurchaninov, Lenoid; Lambo, Ricardo; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Nasr, Sarah Seif El; Silveira, Daniel M.; So, Chukman; Storey, James W.; Thompson, Robert I.; van der Werf, Dirk P.; Wilding, Dean; Wurtele, Jonathan S.; Yamazaki, Yasunori

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consist...

  11. Observation of ferroelastic domains in layered magnetic compounds using birefringence imaging

    Science.gov (United States)

    Miura, Yoko; Okumura, Kazuya; Manaka, Hirotaka

    2018-03-01

    The two-dimensional Heisenberg antiferromagnet (C2H5NH3)2CuCl4 is a candidate compound for the coexistence of ferroelectricity and ferroelasticity; however, the microscopic observations of multiferroic domains may still be unclear. In-plane birefringence imaging measurements were performed to observe the manner in which the ferroelectric and the ferroelastic domains change during phase transitions between 15 K and 300 K. It was found that 90° ferroelastic domains appeared in the ab-plane at 300 K. As the temperature decreased toward 15 K, each domain inverted at a certain temperature (T a) without structural or magnetic phase transitions. The value of T a was found to be significantly influenced by external stresses; therefore, birefringence imaging techniques are useful for investigating variations in ferroelastic domains with temperature. Furthermore, a structural phase transition from orthorhombic to monoclinic or triclinic occurred at 230 ~ 240 K; however, no spontaneous polarization appeared in the ab-plane over the entire investigated range.

  12. Effect of birefringence of lens material on polarization status and optical imaging characteristics

    Science.gov (United States)

    Kim, Wan-Chin; Park, No-Cheol

    2018-04-01

    In most cases of molding with glass or optical polymers, it is expected that there will be birefringence caused by the internal mechanical stresses remaining in the molding material. The distribution of the residual stress can be annealed by slow cooling, but this approach is disadvantageous with respect to the shape accuracy and manufacturing time. In this study, we propose an analytical model to calculate the diffracted field near the focal plane by considering two primary parameters, the orientation angle of the fast axis and the path difference. In order to verify the reliability of the analytical model, we compared the measured beam spot of the F-theta lens of the laser scanning unit (LSU) with the analytical result. In addition, we analyzed the calculated result from the perspective of the polarization status in the exit pupil. The proposed analysis method can be applied to enhance the image quality for cases in which birefringence occurs in a lens material by suitably modeling the amplitude and phase of the incident light flux.

  13. Vacuum birefringence and the x-ray polarization from black-hole accretion disks

    Science.gov (United States)

    Caiazzo, Ilaria; Heyl, Jeremy

    2018-04-01

    In the next decade, x-ray polarimetry will open a new window on the high-energy Universe, as several missions that include an x-ray polarimeter are currently under development. Observations of the polarization of x rays coming from the accretion disks of stellar-mass and supermassive black holes are among the new polarimeters' major objectives. In this paper, we show that these observations can be affected by the quantum electrodynamic (QED) effect of vacuum birefringence: after an x-ray photon is emitted from the accretion disk, its polarization changes as the photon travels through the accretion disk's magnetosphere, as a result of the vacuum becoming birefringent in the presence of a magnetic field. We show that this effect can be important for black holes in the energy band of the upcoming polarimeters and has to be taken into account in a complete model of the x-ray polarization that we expect to detect from black-hole accretion disks, both for stellar mass and for supermassive black holes. We find that, for a chaotic magnetic field in the disk, QED can significantly decrease the linear polarization fraction of edge-on photons, depending on the spin of the hole and on the strength of the magnetic field. This effect can provide, for the first time, a direct way to probe the magnetic field strength close to the innermost stable orbit of black-hole accretion disks and to study the role of magnetic fields in astrophysical accretion in general.

  14. Constraints on cosmological birefringence from PLANCK and Bicep2/Keck data

    Energy Technology Data Exchange (ETDEWEB)

    Gruppuso, A. [INAF-IASF Bologna, Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, Istituto Nazionale di Astrofisica, via Gobetti 101, I-40129 Bologna (Italy); Gerbino, M.; Pagano, L.; Melchiorri, A. [Dipartimento di Fisica and INFN, Università di Roma ' ' La Sapienza' ' , P.le Aldo Moro 2, 00185, Rome (Italy); Natoli, P.; Mandolesi, N.; Molinari, D., E-mail: gruppuso@iasbo.inaf.it, E-mail: martina.gerbino@roma1.infn.it, E-mail: ntlpla@unife.it, E-mail: luca.pagano@roma1.infn.it, E-mail: mandolesi@iasfbo.inaf.it, E-mail: alessandro.melchiorri@roma1.infn.it, E-mail: molinari@iasfbo.inaf.it [Dipartimento di Fisica e Scienze della Terra and INFN, Università degli Studi di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy)

    2016-06-01

    The polarization of cosmic microwave background (CMB) can be used to constrain cosmological birefringence, the rotation of the linear polarization of CMB photons potentially induced by parity violating physics beyond the standard model. This effect produces non-null CMB cross correlations between temperature and B mode-polarization, and between E- and B-mode polarization. Both cross-correlations are otherwise null in the standard cosmological model. We use the recently released 2015 PLANCK likelihood in combination with the Bicep2/Keck/Planck (BKP) likelihood to constrain the birefringence angle α. Our findings, that are compatible with no detection, read α = 0.0° ± 1.3° (stat) ± 1° (sys) for PLANCK data and α = 0.30° ± 0.27° (stat) ± 1° (sys) for BKP data. We finally forecast the expected improvements over present constraints when the PLANCK BB, TB and EB spectra at high ℓ will be included in the analysis.

  15. Periodic reversal of magneto-optic Faraday rotation on uniaxial birefringence crystal with ultrathin magnetic films

    Directory of Open Access Journals (Sweden)

    C. W. Su

    2013-07-01

    Full Text Available An experimental approach of inclined incidence magneto-optic Faraday effect observed in the polar plane is applied. Three samples containing ferromagnetic cobalt ultrathin films on a semiconductor zinc oxide (0001 single crystal substrate with in-plane and out-of-plane anisotropy are evaluated. Through the fine adjustment of crossed polarizers in the magneto-optic effect measurement completely recorded the detail optical and magneto-optical responses from the birefringent crystal substrate and the magnetic film, especially for the signal induced from the substrate with uniaxial optical axis. The angle dependency of interference phenomena periodically from the optical and magneto-optical responses is attributed to the birefringence even in the absence of a magnetic field. The new type of observation finds that the transmission Faraday intensity in the oblique incidence includes a combination of polarization rotations, which results from optical compensation from the substrate and magneto-optical Faraday effects from the film. The samples grown at different rates and examined by this method exhibit magnetic structure discriminations. This result can be applied in the advanced polarized-light technologies to enhance the spatial resolution of magnetic surfaces with microstructural information under various magnetic field direction.

  16. Infrared birefringence imaging of residual stress and bulk defects in multicrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ganapati, Vidya; Schoenfelder, Stephan; Castellanos, Sergio; Oener, Sebastian; Koepge, Ringo; Sampson, Aaron; Marcus, Matthew A.; Lai, Barry; Morhenn, Humphrey; Hahn, Giso; Bagdahn, Joerg; Buonassisi1, Tonio

    2010-05-05

    This manuscript concerns the application of infrared birefringence imaging (IBI) to quantify macroscopic and microscopic internal stresses in multicrystalline silicon (mc-Si) solar cell materials. We review progress to date, and advance four closely related topics. (1) We present a method to decouple macroscopic thermally-induced residual stresses and microscopic bulk defect related stresses. In contrast to previous reports, thermally-induced residual stresses in wafer-sized samples are generally found to be less than 5 MPa, while defect-related stresses can be several times larger. (2) We describe the unique IR birefringence signatures, including stress magnitudes and directions, of common microdefects in mc-Si solar cell materials including: {beta}-SiC and {beta}-Si{sub 3}N{sub 4} microdefects, twin bands, nontwin grain boundaries, and dislocation bands. In certain defects, local stresses up to 40 MPa can be present. (3) We relate observed stresses to other topics of interest in solar cell manufacturing, including transition metal precipitation, wafer mechanical strength, and minority carrier lifetime. (4) We discuss the potential of IBI as a quality-control technique in industrial solar cell manufacturing.

  17. Numerical comparison between Maxwell stress method and equivalent multipole approach for calculation of the dielectrophoretic force in single-cell traps.

    Science.gov (United States)

    Rosales, Carlos; Lim, Kian Meng

    2005-06-01

    This paper presents detailed numerical calculations of the dielectrophoretic force in traps designed for single-cell trapping. A trap with eight planar electrodes is studied for spherical and ellipsoidal particles using the boundary element method (BEM). Multipolar approximations of orders one to three are compared with the full Maxwell stress tensor (MST) calculation of the electrical force on spherical particles. Ellipsoidal particles are also studied, but in their case only the dipolar approximation is available for comparison with the MST solution. The results show that a small number of multipolar terms need to be considered in order to obtain accurate results for spheres, even in the proximity of the electrodes, and that the full MST calculation is only required in the study of non-spherical particles.

  18. Natural enamel caries in polarized light microscopy: differences in histopathological features derived from a qualitative versus a quantitative approach to interpret enamel birefringence.

    Science.gov (United States)

    De Medeiros, R C G; Soares, J D; De Sousa, F B

    2012-05-01

    Lesion area measurement of enamel caries using polarized light microscopy (PLM) is currently performed in a large number of studies, but measurements are based mainly on a mislead qualitative interpretation of enamel birefringence in a single immersion medium. Here, five natural enamel caries lesions are analysed by microradiography and in PLM, and the differences in their histopathological features derived from a qualitative versus a quantitative interpretation of enamel birefringence are described. Enamel birefringence in different immersion media (air, water and quinoline) is interpreted by both qualitative and quantitative approaches, the former leading to an underestimation of the depth of enamel caries mainly when the criterion of validating sound enamel as a negatively birefringent area in immersion in water is used (a current common practice in dental research). Procedures to avoid the shortcomings of a qualitative interpretation of enamel birefringence are presented and discussed. © 2012 The Authors Journal of Microscopy © 2012 Royal Microscopical Society.

  19. Continuous form-dependent focusing of non-spherical microparticles in a highly diluted suspension with the help of microfluidic spirals

    Science.gov (United States)

    Roth, Tanja; Sprenger, Lisa; Odenbach, Stefan; Häfeli, Urs O.

    2018-04-01

    Microfluidic spirals are able to focus non-spherical microparticles in diluted suspension due to the Dean effect. A secondary flow establishes in a curved channel, consisting of two counter-rotating vortices, which transport particles to an equilibrium position near the inner wall of the channel. The relevant size parameter, which is responsible for successful focusing, is the ratio between the particle diameter of a sphere and the hydraulic diameter, which is a characteristic of the microfluidic spiral. A non-spherical particle has not one but several different size parameters. This study investigated the minor and major axes, the equivalent spherical diameter, and the maximal rotational diameter as an equivalent to the spherical diameter. Using a polydimethylsiloxane (PDMS)-based microfluidic device with spirals, experiments were conducted with artificial peanut-shaped and ellipsoidal particles sized between 3 and 9 μm as well as with the bacteria Bacillus subtilis. Our investigations show that the equivalent spherical diameter, the major axis, and the maximal rotational diameter of a non-spherical particle can predict successful focusing. The minor axis is not suitable for this purpose. Non-spherical particles focused when the ratio of their equivalent spherical diameter to the hydraulic diameter of the channel was larger than 0.07. The particles also focused when the ratio between the maximal rotational diameter or the major axis and the hydraulic diameter was larger than 0.01. These results may help us to separate non-spherical biological particles, such as circulating tumor cells or pathogenic bacteria, from blood in future experimental studies.

  20. A study of the effect of non-spherical dust particles on Geostationary Environment Monitoring Spectrometer (GEMS) aerosol optical properties retrievals

    Science.gov (United States)

    Go, S.; Kim, J.; KIM, M.; Choi, M.; Lim, H.

    2017-12-01

    Non-spherical assumption of particle shape has been used to replace the spherical assumption in the Geostationary Environment Monitoring Spectrometer (GEMS) aerosol optical properties retrievals for dust particles. GEMS aerosol retrieval algorithms are based on optimal estimation method to provide aerosol optical depth (AOD), single scattering albedo (SSA) at 443nm, and aerosol loading height (ALH) simultaneously as products. Considering computing time efficiency, the algorithm takes Look-Up Table (LUT) approach using Vector Linearized Discrete Ordinate Radiative Transfer code (VLIDORT), and aerosol optical properties for three aerosol types of absorbing fine aerosol (BC), dust and non-absorbing aerosol (NA) are integrated from AERONET inversion data, and fed into the LUT calculation. In this study, by applying the present algorithm to OMI top-of the atmosphere normalized radiance, retrieved AOD, SSA with both spherical and non-spherical assumptions have been compared to the surface AERONET observations at East Asia sites for 3 years from 2005 to 2007 to evaluate and quantify the effect of non-spherical dust particles on the satellite aerosol retrievals. The root-mean-square error (RMSE) in the satellite retrieved AOD have been slightly reduced as a result of adopting the non-spherical assumption in the GEMS aerosol retrieval algorithm. For SSA, algorithm tested with spheroid models on dust particle shows promising results for the improved SSA. In terms of ALH, the results are qualitatively compared with CALIOP products, and shows consistent variation. This result suggests the importance of taking into account the effects of non-sphericity in the retrieval of dust particles from GEMS measurements.

  1. Scattering by non-spherical particles of size comparable to a wavelength - A new semi-empirical theory

    Science.gov (United States)

    Pollack, J. B.; Cuzzi, J. N.

    1980-01-01

    An approximate method is proposed for evaluating the interaction of randomly oriented, nonspherical particles with the total intensity component of electromagnetic radiation. When the particle size parameter, x, the ratio of particle circumference to wavelength, is less than some upper bound x(o) (about 5), Mie theory is used. For x greater than x(o), the interaction is divided into three components: diffraction, external reflection, and transmission. Physical optics theory is used to obtain the first of these components; geometrical optics theory is applied to the second; and a simple parameterization is employed for the third. The predictions of this theory are found to be in very good agreement with laboratory measurements for a wide variety of particle shapes, sizes, and refractive indexes. Limitations of the theory are also noted.

  2. Test of Mie-based single-scattering properties of non-spherical dust aerosols in radiative flux calculations

    International Nuclear Information System (INIS)

    Fu, Q.; Thorsen, T.J.; Su, J.; Ge, J.M.; Huang, J.P.

    2009-01-01

    We simulate the single-scattering properties (SSPs) of dust aerosols with both spheroidal and spherical shapes at a wavelength of 0.55 μm for two refractive indices and four effective radii. Herein spheres are defined by preserving both projected area and volume of a non-spherical particle. It is shown that the relative errors of the spheres to approximate the spheroids are less than 1% in the extinction efficiency and single-scattering albedo, and less than 2% in the asymmetry factor. It is found that the scattering phase function of spheres agrees with spheroids better than the Henyey-Greenstein (HG) function for the scattering angle range of 0-90 o . In the range of ∼90-180 o , the HG function is systematically smaller than the spheroidal scattering phase function while the spherical scattering phase function is smaller from ∼90 o to 145 o but larger from ∼145 o to 180 o . We examine the errors in reflectivity and absorptivity due to the use of SSPs of equivalent spheres and HG functions for dust aerosols. The reference calculation is based on the delta-DISORT-256-stream scheme using the SSPs of the spheroids. It is found that the errors are mainly caused by the use of the HG function instead of the SSPs for spheres. By examining the errors associated with the delta-four- and delta-two-stream schemes using various approximate SSPs of dust aerosols, we find that the errors related to the HG function dominate in the delta-four-stream results, while the errors related to the radiative transfer scheme dominate in the delta-two-stream calculations. We show that the relative errors in the global reflectivity due to the use of sphere SSPs are always less than 5%. We conclude that Mie-based SSPs of non-spherical dust aerosols are well suited in radiative flux calculations.

  3. Optimization of particle trapping and patterning via photovoltaic tweezers: role of light modulation and particle size

    International Nuclear Information System (INIS)

    Matarrubia, J; García-Cabañes, A; Plaza, J L; Agulló-López, F; Carrascosa, M

    2014-01-01

    The role of light modulation m and particle size on the morphology and spatial resolution of nano-particle patterns obtained by photovoltaic tweezers on Fe : LiNbO 3 has been investigated. The impact of m when using spherical as well as non-spherical (anisotropic) nano-particles deposited on the sample surface has been elucidated. Light modulation is a key parameter determining the particle profile contrast that is optimum for spherical particles and high-m values (m ∼ 1). The minimum particle periodicities reachable are also investigated obtaining periodic patterns up to 3.5 µm. This is a value at least one order of magnitude shorter than those obtained in previous reported experiments. Results are successfully explained and discussed in light of the previous reported models for photorefraction including nonlinear carrier transport and dielectrophoretic trapping. From the results, a number of rules for particle patterning optimization are derived. (paper)

  4. Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles.

    Science.gov (United States)

    Petersen, Claudia G; Vagnini, Laura D; Mauri, Ana L; Massaro, Fabiana C; Silva, Liliane F I; Cavagna, Mario; Baruffi, Ricardo L R; Oliveira, Joao B A; Franco, José G

    2011-04-23

    This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF) intensity and the nuclear (NM) and cytoplasmic (CM) in vitro maturation of human oocytes from stimulated cycles. The ZP-BF was evaluated under an inverted microscope with a polarizing optical system and was scored as high/positive (when the ZP image presented a uniform and intense birefringence) or low/negative (when the image presented moderate and heterogeneous birefringence). CM was analyzed by evaluating the distribution of cortical granules (CGs) throughout the ooplasm by immunofluorescence staining. CM was classified as: complete, when CG was localized in the periphery; incomplete, when oocytes presented a cluster of CGs in the center; or in transition, when oocytes had both in clusters throughout cytoplasm and distributed in a layer in the cytoplasm periphery Nuclear maturation: From a total of 83 germinal vesicle (GV) stage oocytes, 58 of oocytes (69.9%) reached NM at the metaphase II stage. From these 58 oocytes matured in vitro, the high/positively scoring ZP-BF was presented in 82.7% of oocytes at the GV stage, in 75.8% of oocytes when at the metaphase I, and in 82.7% when oocytes reached MII. No relationship was observed between NM and ZP-BF positive/negative scores (P = 0.55). These variables had a low Pearson's correlation coefficient (r = 0.081). Cytoplasmic maturation: A total of 85 in vitro-matured MII oocytes were fixed for CM evaluation. Forty-nine oocytes of them (57.6%) showed the complete CM, 30 (61.2%) presented a high/positively scoring ZP-BF and 19 (38.8%) had a low/negatively scoring ZP-BF. From 36 oocytes (42.3%) with incomplete CM, 18 (50%) presented a high/positively scoring ZPBF and 18 (50%) had a low/negatively scoring ZP-BF. No relationship was observed between CM and ZP-BF positive/negative scores (P = 0.42). These variables had a low Pearson's correlation coefficient (r = 0.11). The current study demonstrated an absence of

  5. Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles

    Directory of Open Access Journals (Sweden)

    Silva Liliane FI

    2011-04-01

    Full Text Available Abstract Background This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF intensity and the nuclear (NM and cytoplasmic (CM in vitro maturation of human oocytes from stimulated cycles. Results The ZP-BF was evaluated under an inverted microscope with a polarizing optical system and was scored as high/positive (when the ZP image presented a uniform and intense birefringence or low/negative (when the image presented moderate and heterogeneous birefringence. CM was analyzed by evaluating the distribution of cortical granules (CGs throughout the ooplasm by immunofluorescence staining. CM was classified as: complete, when CG was localized in the periphery; incomplete, when oocytes presented a cluster of CGs in the center; or in transition, when oocytes had both in clusters throughout cytoplasm and distributed in a layer in the cytoplasm periphery Nuclear maturation: From a total of 83 germinal vesicle (GV stage oocytes, 58 of oocytes (69.9% reached NM at the metaphase II stage. From these 58 oocytes matured in vitro, the high/positively scoring ZP-BF was presented in 82.7% of oocytes at the GV stage, in 75.8% of oocytes when at the metaphase I, and in 82.7% when oocytes reached MII. No relationship was observed between NM and ZP-BF positive/negative scores (P = 0.55. These variables had a low Pearson's correlation coefficient (r = 0.081. Cytoplasmic maturation: A total of 85 in vitro-matured MII oocytes were fixed for CM evaluation. Forty-nine oocytes of them (57.6% showed the complete CM, 30 (61.2% presented a high/positively scoring ZP-BF and 19 (38.8% had a low/negatively scoring ZP-BF. From 36 oocytes (42.3% with incomplete CM, 18 (50% presented a high/positively scoring ZPBF and 18 (50% had a low/negatively scoring ZP-BF. No relationship was observed between CM and ZP-BF positive/negative scores (P = 0.42. These variables had a low Pearson's correlation coefficient (r = 0.11. Conclusions The current

  6. A Key Experiment of Quantum Optics: The Transfer of Spin Angular Momentum from Photons to a Birefringent Particle

    Energy Technology Data Exchange (ETDEWEB)

    Frins, E [Universidad de la Republica, Montevideo (Uruguay); Dultz, W [J.W.v.Goethe Universitaet Frankfurt/Main (Germany); Schmitzer, H, E-mail: requalivahanus@t-online.de [Xavier University, Cincinnati (United States)

    2011-01-01

    Rotating small birefringent particles with the spin angular momentum of light is a key experiment of quantum optics. We derive the equation of motion of small retarders in viscose liquids, demonstrate their some times irregular rotation in polarized light, and discuss possible technical applications.

  7. Temperature Compensated Strain Sensor Based on Cascaded Sagnac Interferometers and All-Solid Birefringent Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Wu; He, Sailing

    2012-01-01

    We demonstrate a temperature compensated strain sensor with two cascaded Sagnac interferometers, that provide strain sensing and temperature compensation, respectively. The Sagnac interferometers use an all-solid hybrid photonic crystal fiber with stress-induced birefringence. The stress-induced ...

  8. Reduction of birefringence in a skin-layer of injection molded polymer strips using CO{sub 2} laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kurosaki, Yasuo; Satoh, Isao; Saito, Takushi [Tokyo Inst. of Tech. (Japan). Dept. of Mechanical Intelligent Systems Engineering

    1995-12-31

    Injection molding of polymers is currently utilized for numerous industrial applications. Because of high productivity and stable quality of molded products, the injection-molding process makes the production costs lower, and therefore, is expected to spread more widely in the future. This paper deals with a technique for improving the optical quality of injection molded polymer products using radiative heating. The birefringence frozen in a skin-layer of the molded part was reduced by CO{sub 2} laser heating, and the efficiency of this technique was investigated experimentally. Namely, a simple numerical calculation was performed to estimate the heating efficiency of CO{sub 2} laser in the polymer, effects of radiation heating on the skin-layer of the molded polymer were observed by using a mold with transparent windows, and the residual birefringence frozen in the final molded specimen was measured. The results clearly showed that the birefringence in the skin-layer of injection molded polymer strips was reduced with CO{sub 2} laser heating. The authors believe that the proposed method for reducing the birefringence frozen in injection-molded polymer products is suitable for practical molding, because process time required for the injection-molding is only slightly increased with this method.

  9. Spectral-Domain Measurement of Strain Sensitivity of a Two-Mode Birefringent Side-Hole Fiber

    Directory of Open Access Journals (Sweden)

    Waclaw Urbanczyk

    2012-09-01

    Full Text Available The strain sensitivity of a two-mode birefringent side-hole fiber is measured in the spectral domain. In a simple experimental setup comprising a broadband source, a polarizer, a two-mode birefringent side-hole fiber under varied elongations, an analyzer and a compact spectrometer, the spectral interferograms are resolved. These are characterized by the equalization wavelength at which spectral interference fringes have the highest visibility (the largest period due to the zero group optical path difference between the fundamental, the LP01 mode and the higher-order, the LP11 mode. The spectral interferograms with the equalization wavelength are processed to retrieve the phase as a function of the wavelength. From the retrieved phase functions corresponding to different elongations of a two-mode birefringent side-hole fiber under test, the spectral strain sensitivity is obtained. Using this approach, the intermodal spectral strain sensitivity was measured for both x and y polarizations. Moreover, the spectral polarimetric sensitivity to strain was measured for the fundamental mode when a birefringent delay line was used in tandem with the fiber. Its spectral dependence was also compared with that obtained from a shift of the spectral interferograms not including the equalization wavelength, and good agreement was confirmed.

  10. Highly birefringent photonic crystal fiber with ultra-flattened negative dispersion over S + C + L + U bands

    DEFF Research Database (Denmark)

    Habib, Selim; Khandker, Emran

    2015-01-01

    We present a new cladding design for photonic crystal fiber (PCF) on a decagonal structure to simultaneously achieve ultra-flattened large negative dispersion and ultrahigh birefringence. Numerical results confirm that the proposed PCFexhibits ultra-flattened large negative dispersion over the S ...

  11. Physics with Trapped Antihydrogen

    Science.gov (United States)

    Charlton, Michael

    2017-04-01

    For more than a decade antihydrogen atoms have been formed by mixing antiprotons and positrons held in arrangements of charged particle (Penning) traps. More recently, magnetic minimum neutral atom traps have been superimposed upon the anti-atom production region, promoting the trapping of a small quantity of the antihydrogen yield. We will review these advances, and describe some of the first physics experiments performed on anrtihydrogen including the observation of the two-photon 1S-2S transition, invesigation of the charge neutrailty of the anti-atom and studies of the ground state hyperfine splitting. We will discuss the physics motivations for undertaking these experiments and describe some near-future initiatives.

  12. Ion trap device

    Science.gov (United States)

    Ibrahim, Yehia M.; Smith, Richard D.

    2016-01-26

    An ion trap device is disclosed. The device includes a series of electrodes that define an ion flow path. A radio frequency (RF) field is applied to the series of electrodes such that each electrode is phase shifted approximately 180 degrees from an adjacent electrode. A DC voltage is superimposed with the RF field to create a DC gradient to drive ions in the direction of the gradient. A second RF field or DC voltage is applied to selectively trap and release the ions from the device. Further, the device may be gridless and utilized at high pressure.

  13. Asymmetric ion trap

    Science.gov (United States)

    Barlow, Stephan E.; Alexander, Michael L.; Follansbee, James C.

    1997-01-01

    An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity.

  14. Polarization-maintaining, double-clad fiber amplifier employing externally applied stress-induced birefringence

    International Nuclear Information System (INIS)

    Koplow, Jeffrey P.; Goldberg, Lew; Moeller, Robert P.; Kliner, Dahv A. V.

    2000-01-01

    We report a new approach to obtaining linear-polarization operation of a rare-earth-doped fiber amplifier in which the gain fiber is coiled under tension to induce birefringence. We demonstrated this method by constructing an Er/Yb-doped, double-clad, single-mode fiber amplifier with an output power of 530 mW and a polarization extinction ratio of >17 dB (when seeded with linearly polarized light) at a wavelength of ∼1.5 μm . The technique is achromatic, permits single- or multiple-pass operation of the amplifier, requires no additional components in the optical path, leaves the fiber ends unobstructed, and is inexpensive to implement. (c) 2000 Optical Society of America

  15. Analysis of photoinduced birefringence in azo-dye doped films by a fast imaging technique

    International Nuclear Information System (INIS)

    Marino, Iari-Gabriel; Lottici, Pier Paolo

    2010-01-01

    In photo-birefringent films, the relationship ρ(I) between optical retardation ρ and pump irradiance I may be obtained with imaging techniques applied within a pump-probe setup. However, measurement of ρ(I) are reported only at long irradiation times and low time-resolution. In this paper we describe a polariscopic imaging technique with higher sensitivity (by a factor of ∼ 30), where the probe beam is focused on the entrance pupil of the camera ('Maxwellian view'). The technique is applied to an azo-dye doped polymeric film, obtaining the continuous ρ(I) curve after irradiation times from 10 ms to 240 ms. Exponential functions are fitted against the experimental data both as a function of time and irradiance.

  16. Optical Search for QED vacuum magnetic birefringence, Axions and photon Regeneration

    CERN Multimedia

    Pugnat, P; Hryczuk, A; Finger, M; Finger, M; Kral, M

    2007-01-01

    Since its prediction in 1936 by Euler, Heisenberg and Weisskopf in the earlier development of the Quantum Electrodynamic (QED) theory, the Vacuum Magnetic Birefringence (VMB) is still a challenge for optical metrology techniques. According to QED, the vacuum behaves as an optically active medium in the presence of an external magnetic field. It can be experimentally probed with a linearly polarized laser beam. After propagating through the vacuum submitted to a transverse magnetic field, the polarization of the laser beam will change to elliptical and the parameters of the polarization are directly related to fundamental constants such as the fine structure constant and the electron Compton wavelength. Contributions to the VMB could also arise from the existence of light scalar or pseudo-scalar particles like axions that couple to two photons and this would manifest itself as a sizeable deviation from the initial QED prediction. On one side, the interest in axion search, providing an answer to the strong-CP p...

  17. Novel birefringence interrogation for Sagnac loop interferometer sensor with unlimited linear measurement range.

    Science.gov (United States)

    He, Haijun; Shao, Liyang; Qian, Heng; Zhang, Xinpu; Liang, Jiawei; Luo, Bin; Pan, Wei; Yan, Lianshan

    2017-03-20

    A novel demodulation method for Sagnac loop interferometer based sensor has been proposed and demonstrated, by unwrapping the phase changes with birefringence interrogation. A temperature sensor based on Sagnac loop interferometer has been used to verify the feasibility of the proposed method. Several tests with 40 °C temperature range have been accomplished with a great linearity of 0.9996 in full range. The proposed scheme is universal for all Sagnac loop interferometer based sensors and it has unlimited linear measurable range which overwhelming the conventional demodulation method with peak/dip tracing. Furthermore, the influence of the wavelength sampling interval and wavelength span on the demodulation error has been discussed in this work. The proposed interrogation method has a great significance for Sagnac loop interferometer sensor and it might greatly enhance the availability of this type of sensors in practical application.

  18. Interrogation cradle and insertable containment fixture for detecting birefringent microcrystals in bile

    Science.gov (United States)

    Darrow, Chris; Seger, Tino

    2003-09-30

    A transparent flow channel fluidly communicates a fluid source and a collection reservoir. An interrogating light beam passes through a first polarizer having a first plane of polarization. The flow channel is orthogonal to the light beam. The light beam passes through a fluid sample as it flows through the flow channel, and is then filtered through a second polarizer having a second plane of polarization rotated 90.degree. from the first plane of polarization. An electronic photo-detector is aligned with the light beam, and signals the presence of birefringent microcrystals in the fluid sample by generating voltage pulses. A disposable containment fixture includes the flow channel and the collection reservoir. The fixture is adapted for removable insertion into an interrogation cradle that includes optical and data processing components. The cradle rigidly positions the centerline of the flow channel orthogonal to the light beam.

  19. Cladding defects in hollow core fibers for surface mode suppression and improved birefringence

    DEFF Research Database (Denmark)

    Michieletto, Mattia; Lyngso, J. K.; Lægsgaard, Jesper

    2014-01-01

    We demonstrate a novel polarization maintaining hollow-core photonic bandgap fiber geometry that reduces the impact of surface modes on fiber transmission. The cladding structure is modified with a row of partially collapsed holes to strip away unwanted surface modes. A theoretical investigation...... of the surface mode stripping is presented and compared to the measured performance of four 7-cells core fibers that were drawn with different collapse ratio of the defects. The varying pressure along the defect row in the cladding during drawing introduces an ellipticity of the core. This, combined...... with the presence of antiresonant features on the core wall, makes the fibers birefringent, with excellent polarization maintaining properties. (C) 2014 Optical Society of America...

  20. Novel configuration for an enhanced and compact all-fiber Faraday rotator with matched birefringence.

    Science.gov (United States)

    Asraf, Sagie; Sintov, Yoav; Zalevsky, Zeev

    2017-08-07

    We propose a novel configuration for an improved and compact all fiber Faraday rotator based on phase matching between the Faraday rotation and bend-induced birefringence. The device utilizes a coiled fiber within two electro-magnetic toroids, such that the fiber length required for getting the beat length is quite long and several rounds of fiber are needed. Analysis of the capabilities of the proposed device and its sensitivity to different parameters is presented. Faraday rotation of 13° was experimentally measured in six meters of single mode silica fiber, with a magnetic field of about 0.06T at a wavelength of 1064nm. We show that phase matching between the two phenomena significantly improves the polarization rotation by a factor of 4-10. In addition, we demonstrate the ability to achieve higher rotation by using Fabry Perot resonator in low terbium doped glass.

  1. Birefringent Crystals and Abdominal Discoloration in the Predatory Mite Phytoseiulus persimilis (Acari: Phytoseiidae)

    Science.gov (United States)

    Bjørnson; Steiner; Keddie

    1997-03-01

    In response to grower complaints of poor performance of Phytoseiulus persimilis, mites from 14 commercial insectaries and research colonies were examined for pathogens. Some were found to have abdominal discolorations, manifested initially as two white stripes along the dorsal sides of the body within the Malpighian tubules. Advanced signs appeared as a large, centrally located, white spot or U-shaped discoloration in the distal opisthosoma within the rectum/anal atrium. White material often accumulated and hardened within the anus and formed a rectal plug that inhibited further excretion. Most affected mites were lethargic. Adults and immatures with abdominal discoloration contained numerous densely packed, birefringent, dumbbell-shaped entities. Though occasionally observed in the colon, they occurred most frequently within the Malpighian tubules and/or rectum and anal atrium. Dumbbells measured 2-4 &mgr;m long and contained prominent concentric rings. When observed by transmission electron microscopy, the entities lacked cellular organelles. Asymptomatic mites contained few or no such entities. Dumbbell-shaped inclusions were observed in P. persimilis from all sources examined. High levels of potassium, low levels of phosphorous and sulfur, and traces of chlorine were detected by energy-dispersive X-ray analysis. Guanine and uric acid, known nitrogenous wastes of arachnids, do not contain these elements. The chemical composition and structure indicate that the dumbbells are crystals. Both asymptomatic mites and those specimens exhibiting abdominal discoloration were examined for pathogens using light and transmission electron microscopy. Microsporidia, virus-like particles, and a rickettsia (genus Wolbachia) were observed in some mites but showed no correlation with white abdominal discoloration or associated crystal formation. Neither were pathogens always detected in symptomatic mites. Although birefringent crystals may be naturally occurring excretory

  2. Constraints on direction-dependent cosmic birefringence from Planck polarization data

    Science.gov (United States)

    Contreras, Dagoberto; Boubel, Paula; Scott, Douglas

    2017-12-01

    Cosmic birefringence is the process that rotates the plane of polarization by an amount, α, as photons propagate through free space. Such an effect arises in parity-violating extensions to the electromagnetic sector, such as the Chern-Simons term common in axion models, quintessence models, or Lorentz-violating extensions to the standard model. Most studies consider the monopole of this rotation, but it is also possible for the effect to have spatial anisotropies. Paying particular attention to large scales, we implement a novel pixel-based method to extract the spherical harmonics for L 30. Our results are consistent with no detection and we set 95 % upper limits on the amplitude of a scale-invariant power spectrum of L(L+1)CL/2π<[2.2 (stat.)±0.7 (syst.)]×10-5=[0.07 (stat.)±0.02 (syst.)] deg2, on par with previous constraints. This implies specific limits on the dipole and quadrupole amplitudes to be √C1/4π lesssim 0.o2 and √C2/4π lesssim 0.o1, at 95 % CL, respectively, improving previous constraints by an order of magnitude. We further constrain a model independent M=0 quadrupole in an arbitrary direction to be α20 = 0.o02 ± 0.o21, with an unconstrained direction. However, we find an excess of dipolar power with an amplitude √3C1/4π = 0.o32±0.o10 (stat.)±0.o08 (syst.)], in the direction (l,b)=(295o,17o)±(22o,17o) (stat.)±(5o,16o) (syst.), larger than 1.4 % of simulations with no birefringence. We attribute part of this signal to the contamination of residual foregrounds not accounted for in our simulations, although this should be further investigated.

  3. Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies.

    Science.gov (United States)

    Isabettini, Stéphane; Baumgartner, Mirjam E; Fischer, Peter; Windhab, Erich J; Liebi, Marianne; Kuster, Simon

    2018-01-03

    Bicelles are tunable disk-like polymolecular assemblies formed from a large variety of lipid mixtures. Applications range from membrane protein structural studies by nuclear magnetic resonance (NMR) to nanotechnological developments including the formation of optically active and magnetically switchable gels. Such technologies require high control of the assembly size, magnetic response and thermal resistance. Mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and its lanthanide ion (Ln 3+ ) chelating phospholipid conjugate, 1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylene triaminepentaacetate (DMPE-DTPA), assemble into highly magnetically responsive assemblies such as DMPC/DMPE-DTPA/Ln 3+ (molar ratio 4:1:1) bicelles. Introduction of cholesterol (Chol-OH) and steroid derivatives in the bilayer results in another set of assemblies offering unique physico-chemical properties. For a given lipid composition, the magnetic alignability is proportional to the bicelle size. The complexation of Ln 3+ results in unprecedented magnetic responses in terms of both magnitude and alignment direction. The thermo-reversible collapse of the disk-like structures into vesicles upon heating allows tailoring of the assemblies' dimensions by extrusion through membrane filters with defined pore sizes. The magnetically alignable bicelles are regenerated by cooling to 5 °C, resulting in assembly dimensions defined by the vesicle precursors. Herein, this fabrication procedure is explained and the magnetic alignability of the assemblies is quantified by birefringence measurements under a 5.5 T magnetic field. The birefringence signal, originating from the phospholipid bilayer, further enables monitoring of polymolecular changes occurring in the bilayer. This simple technique is complementary to NMR experiments that are commonly employed to characterize bicelles.

  4. WATER-TRAPPED WORLDS

    International Nuclear Information System (INIS)

    Menou, Kristen

    2013-01-01

    Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO 2 as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe

  5. Redesigning octopus traps

    Directory of Open Access Journals (Sweden)

    Eduarda Gomes

    2014-06-01

    In order to minimise the identified problems in the actual traps, the present work proposes a new design with the aim of reducing the volume and weight during transport, and also during onshore storage. Alternative materials to avoid corrosion and formation of encrustations were also proposed.

  6. WATER-TRAPPED WORLDS

    Energy Technology Data Exchange (ETDEWEB)

    Menou, Kristen [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

    2013-09-01

    Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO{sub 2} as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe.

  7. [Trapping techniques for Solenopsis invicta].

    Science.gov (United States)

    Liang, Xiao-song; Zhang, Qiang; Zhuang, Yiong-lin; Li, Gui-wen; Ji, Lin-peng; Wang, Jian-guo; Dai, Hua-guo

    2007-06-01

    A field study was made to investigate the trapping effects of different attractants, traps, and wind directions on Solenopsis invicta. The results showed that among the test attractants, TB1 (50 g fishmeal, 40 g peptone, 10 ml 10% sucrose water solution and 20 ml soybean oil) had the best effect, followed by TB2 (ham), TB6 (100 g cornmeal and 20 ml soybean oil) and TB4 (10 ml 10% sucrose water solution, 100 g sugarcane powder and 20 ml soybean oil), with a mean capture efficiency being 77.6, 58.7, 29 and 7.7 individuals per trap, respectively. No S. invicta was trapped with TB3 (10 ml 10% sucrose water solution, 100 g cornmeal and 20 ml soybean oil) and TB5 (honey). Tube trap was superior to dish trap, with a trapping efficiency of 75.2 and 35 individuals per trap, respectively. The attractants had better effects in leeward than in windward.

  8. Optical trapping of gold aerosols

    DEFF Research Database (Denmark)

    Schmitt, Regina K.; Pedersen, Liselotte Jauffred; Taheri, S. M.

    2015-01-01

    Aerosol trapping has proven challenging and was only recently demonstrated.1 This was accomplished by utilizing an air chamber designed to have a minimum of turbulence and a laser beam with a minimum of aberration. Individual gold nano-particles with diameters between 80 nm and 200 nm were trapped...... in air using a 1064 nm laser. The positions visited by the trapped gold nano-particle were quantified using a quadrant photo diode placed in the back focal plane. The time traces were analyzed and the trapping stiffness characterizing gold aerosol trapping determined and compared to aerosol trapping...... of nanometer sized silica and polystyrene particles. Based on our analysis, we concluded that gold nano-particles trap more strongly in air than similarly sized polystyrene and silica particles. We found that, in a certain power range, the trapping strength of polystyrene particles is linearly decreasing...

  9. Escaping the tolerance trap

    International Nuclear Information System (INIS)

    Hammoudeh, S.; Madan, V.

    1994-01-01

    In order to examine the implications of the weakening of OPEC's responsiveness in adjusting its production levels, this paper explicitly incorporates rigidity in the quantity adjustment mechanism, thereby extending previous research which assumed smooth quantity adjustments. The rigidity is manifested in a tolerance range for the discrepancy between the declared target price and that of the market. This environment gives rise to a 'tolerance trap' which impedes the convergence process and inevitably brings the market to a standstill before its reaches the targeted price and revenue objectives. OPEC's reaction to the standstill has important implications for the achievement of the target-based equilibrium and for the potential collapse of the market price. This paper examines OPEC's policy options in the tolerance trap and reveals that the optional policy in order to break this impasse and move closer to the equilibrium point is gradually to reduce output and not to flood the market. (Author)

  10. Trapped Ion Qubits

    Energy Technology Data Exchange (ETDEWEB)

    Maunz, Peter Lukas Wilhelm

    2017-04-01

    Qubits can be encoded in clock states of trapped ions. These states are well isolated from the environment resulting in long coherence times [1] while enabling efficient high-fidelity qubit interactions mediated by the Coulomb coupled motion of the ions in the trap. Quantum states can be prepared with high fidelity and measured efficiently using fluorescence detection. State preparation and detection with 99.93% fidelity have been realized in multiple systems [1,2]. Single qubit gates have been demonstrated below rigorous fault-tolerance thresholds [1,3]. Two qubit gates have been realized with more than 99.9% fidelity [4,5]. Quantum algorithms have been demonstrated on systems of 5 to 15 qubits [6–8].

  11. Nonlinear polarization dynamics in a weakly birefringent all-normal dispersion photonic crystal fiber : toward a practical coherent fiber supercontinuum laser

    DEFF Research Database (Denmark)

    Tu, Haohua; Liu, Yuan; Liu, Xiaomin

    2012-01-01

    Dispersion-flattened dispersion-decreased all-normal dispersion (DFDD-ANDi) photonic crystal fibers have been identified as promising candidates for high-spectral-power coherent supercontinuum (SC) generation. However, the effects of the unintentional birefringence of the fibers on the SC generat...... of polarization-maintaining DFDD-ANDi fibers to avoid these adverse effects in pursuing a practical coherent fiber SC laser.......Dispersion-flattened dispersion-decreased all-normal dispersion (DFDD-ANDi) photonic crystal fibers have been identified as promising candidates for high-spectral-power coherent supercontinuum (SC) generation. However, the effects of the unintentional birefringence of the fibers on the SC...... generation have been ignored. This birefringence is widely present in nonlinear non-polarization maintaining fibers with a typical core size of 2 µm, presumably due to the structural symmetry breaks introduced in the fiber drawing process. We find that an intrinsic form-birefringence on the order of 10...

  12. Sediment Trapping in Estuaries

    Science.gov (United States)

    Burchard, Hans; Schuttelaars, Henk M.; Ralston, David K.

    2018-01-01

    Estuarine turbidity maxima (ETMs) are generated by a large suite of hydrodynamic and sediment dynamic processes, leading to longitudinal convergence of cross-sectionally integrated and tidally averaged transport of cohesive and noncohesive suspended particulate matter (SPM). The relative importance of these processes for SPM trapping varies substantially among estuaries depending on topography, fluvial and tidal forcing, and SPM composition. The high-frequency dynamics of ETMs are constrained by interactions with the low-frequency dynamics of the bottom pool of easily erodible sediments. Here, we use a transport decomposition to present processes that lead to convergent SPM transport, and review trapping mechanisms that lead to ETMs at the landward limit of the salt intrusion, in the freshwater zone, at topographic transitions, and by lateral processes within the cross section. We use model simulations of example estuaries to demonstrate the complex concurrence of ETM formation mechanisms. We also discuss how changes in SPM trapping mechanisms, often caused by direct human interference, can lead to the generation of hyperturbid estuaries.

  13. Clinical Long-Term Outcome and Reinterventional Rate After Uterine Fibroid Embolization with Nonspherical Versus Spherical Polyvinyl Alcohol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Duvnjak, Stevo, E-mail: stevo.duvnjak@rsyd.dk [Odense University Hospital, Department of Radiology (Denmark); Ravn, Pernille [Odense University Hospital, Department of Gynecology (Denmark); Green, Anders [Odense University Hospital, Odense Patient Data Explorative Network (Denmark); Andersen, Poul Erik [Odense University Hospital, Department of Radiology (Denmark)

    2016-02-15

    PurposeThis study was designed to evaluate the long-term clinical outcome and frequency of reinterventions in patients with uterine fibroids treated with embolization at a single center using polyvinyl alcohol microparticles.MethodsThe study included all patients with symptomatic uterine fibroids treated with uterine fibroid embolization (UFE) with spherical (s-PVA) and nonspherical (ns-PVA) polyvinyl alcohol microparticles during the period January 2001 to January 2011. Clinical success and secondary interventions were examined. Hospital records were reviewed during follow-up, and symptom-specific questionnaires were sent to all patients.ResultsIn total, 515 patients were treated with UFE and 350 patients (67 %) were available for long-term clinical follow-up. Median time of follow-up was 93 (range 76–120.2) months. Eighty-five patients (72 %) had no reinterventions during follow-up in the group embolized with ns-PVA compared with 134 patients (58 %) treated with s-PVA. Thirty-three patients (28 %) underwent secondary interventions in the ns-PVA group compared with 98 patients (42 %) in s-PVA group (χ{sup 2} test, p < 0.01).ConclusionsSpherical PVA particles 500–700 µm showed high reintervention rate at long-term follow-up, and almost one quarter of the patients underwent secondary interventions, suggesting that this type of particle is inappropriate for UFE.

  14. Theoretical calculations of the deposition of non-spherical particles in the upper airways of the human lung

    International Nuclear Information System (INIS)

    Sturm, Robert; Hofmann, Werner

    2009-01-01

    In the contribution presented here a computer model for the description of non-spherical particle deposition in the upper human respiratory tract is introduced. The theoretical approach is mainly based on the principle of the aerodynamic diameter, whose calculation was carried out according to most current scientific findings. With the help of this parameter deposition patterns for various particle categories (fibers and oblate disks) and breathing conditions (sitting, light-work and hard-work breathing) were simulated. Concerning cylindrical fibers with a diameter ≥ 1 μm, an increase of the aspect ratio β (i.e. particle length/particle diameter) causes a significant enhancement of deposition in the uppermost regions of the respiratory tract (oropharynx, larynx, trachea). This effect is additionally intensified by an increase of the inhalative flow. Regarding the oblate disks with a diameter ≥ 1 μm, any decrease of the aspect ratio leads to an enhancement of deposition in the deeper lung regions, representing an effect contrary to that observed for fibers. An increase of the inhalative flow only induces a limited decrease of the effect. (orig.)

  15. Study of non-spherical bubble oscillations near a surface in a weak acoustic standing wave field.

    Science.gov (United States)

    Xi, Xiaoyu; Cegla, Frederic; Mettin, Robert; Holsteyns, Frank; Lippert, Alexander

    2014-04-01

    The interaction of acoustically driven bubbles with a wall is important in many applications of ultrasound and cavitation, as the close boundary can severely alter the bubble dynamics. In this paper, the non-spherical surface oscillations of bubbles near a surface in a weak acoustic standing wave field are investigated experimentally and numerically. The translation, the volume, and surface mode oscillations of bubbles near a flat glass surface were observed by a high speed camera in a standing wave cell at 46.8 kHz. The model approach is based on a modified Keller-Miksis equation coupled to surface mode amplitude equations in the first order, and to the translation equations. Modifications are introduced due to the adjacent wall. It was found that a bubble's oscillation mode can change in the presence of the wall, as compared to the bubble in the bulk liquid. In particular, the wall shifts the instability pressure thresholds to smaller driving frequencies for fixed bubble equilibrium radii, or to smaller equilibrium radii for fixed excitation frequency. This can destabilize otherwise spherical bubbles, or stabilize bubbles undergoing surface oscillations in the bulk. The bubble dynamics observed in experiment demonstrated the same trend as the theoretical results.

  16. Theory of the Sagnac's interferometer of low birefringence and twist fiber; Teoria del interferometro de Sagnac de fibra de baja birrefrigencia y torcida

    Energy Technology Data Exchange (ETDEWEB)

    Estudillo-Ayala, J. M.; Kuzin, E. A.; Ibarra-Escamilla, B. [Instituto Nacional de Astrofisica, Optica y Electronica, Puebla (Mexico); Rojas-Laguna, R. [Universidad de Guanajuato, Guanajuato (Mexico)

    2001-06-01

    The fibre Sagnac interferometer of low birefringence and twist in the lineal region is examined numerically, a method is shown to measure the birefringence in the fibers and rotation of the axes inside of the interferometer fibre loop. [Spanish] El interferometro de Sagnac de fibra de baja birrefrigencia y torcida en la region lineal es numericamente examinado, se muestra un metodo para medir la birrefrigencia en las fibras y rotacion de los ejes dentro de la fibra del lazo del interferometro.

  17. Birefringence profile adjustment by spatial overlap of nanogratings induced by ultra-short laser pulses inside fused silica

    Science.gov (United States)

    Arabanian, Atoosa Sadat; Najafi, Somayeh; Ajami, Aliasghar; Husinsky, Wolfgang; Massudi, Reza

    2018-02-01

    We have succeeded in realizing a method to control the spatial distribution of optical retardation as a result of nanogratings in bulk-fused silica induced by ultrashort laser pulses. A colorimetry-based retardation measurement (CBRM) based on the Michel-Levy interference color chart using a polarization microscope is used to determine the profiles of the optical retardation. Effects of the spatial overlap of written regions as well as the energy and polarization of the writing pulses on the induced retardations are studied. It has been found that the spatial overlap of lines written by pulse trains with different energies and polarizations can result in an adjustment of the induced birefringence in the overlap region. This approach offers the possibility of designing polarization-sensitive components with a desired birefringence profile.

  18. The use of Lorentz group formalism in solving polarization effects of a birefringent single mode optical fiber

    International Nuclear Information System (INIS)

    Ishiekwene, G.C.; Brown, C.S.; Mensah, S.Y.; Bak, A.E.

    2000-07-01

    A theoretical analysis on the polarization effects of a light beam propagating in a birefringent single-mode fiber is presented. We derive a system of differential equations representing the evolution of Stokes parameters and illustrate their application to polarization effects in a straight birefringent single mode optical fiber. The solutions to the set of equations are obtained using specifically the methods of the unified formalism for polarization optics which adopt the use of the Stokes-Mueller equation and the Lorentz group to model polarization phenomena in media such as optical fibers. The analytical results presented using this approach are identical to results obtained from other conventional methods. We observe the characteristic exponential decrease in the total intensity of the input light due to attenuation by the fiber. (author)

  19. Ultra-flattened nearly-zero dispersion and ultrahigh nonlinear slot silicon photonic crystal fibers with ultrahigh birefringence

    Science.gov (United States)

    Liao, Jianfei; Xie, Yingmao; Wang, Xinghua; Li, Dongbo; Huang, Tianye

    2017-07-01

    A slot silicon photonic crystal fiber (PCF) is proposed to simultaneously achieve ultrahigh birefringence, large nonlinearity and ultra-flattened nearly-zero dispersion over a wide wavelength range. By taking advantage on the slot effect, ultrahigh birefringence up to 0.0736 and ultrahigh nonlinear coefficient up to 211.48 W-1 m-1 for quasi-TE mode can be obtained at the wavelength of 1.55 μm. Moreover, ultra-flattened dispersion of 0.49 ps/(nm km) for quasi-TE mode can be achieved over a 180 nm wavelength range with low dispersion slope of 1.85 × 10-3 ps/(nm2 km) at 1.55 μm. Leveraging on these advantages, the proposed slot PCF has great potential for efficient all-optical signal processing applications.

  20. Temporal laser pulse shaping for RF photocathode guns: the cheap and easy way using UV birefringent crystals

    International Nuclear Information System (INIS)

    Power, J.G.; Jing, C.

    2009-01-01

    We report experimental investigations into a new technique for achieving temporal laser pulse shaping for RF photocathode gun applications using inexpensive UV birefringent crystals. Exploiting the group velocity mismatch between the two different polarizations of a birefringent crystal, a stack of UV pulses can be assembled into the desired temporal pulse shape. The scheme is capable of generating a variety of temporal pulse shapes including: (i) flat-top pulses with fast rise-time and variable pulse duration. (ii) microbunch trains, and (iii) ramped pulse generation. We will consider two applications for beam generation at the Argonne Wakefield Accelerator (AWA) including a flat-top laser pulse for low emittance production and matched bunch length for enhanced transformer ratio production. Streak camera measurements of the temporal profiles generated with a 2-crystal set and a 4-crystal set are presented.

  1. In vivo glucose monitoring using dual-wavelength polarimetry to overcome corneal birefringence in the presence of motion.

    Science.gov (United States)

    Pirnstill, Casey W; Malik, Bilal H; Gresham, Vincent C; Coté, Gerard L

    2012-09-01

    Over the past 35 years considerable research has been performed toward the investigation of noninvasive and minimally invasive glucose monitoring techniques. Optical polarimetry is one noninvasive technique that has shown promise as a means to ascertain blood glucose levels through measuring the glucose concentrations in the anterior chamber of the eye. However, one of the key limitations to the use of optical polarimetry as a means to noninvasively measure glucose levels is the presence of sample noise caused by motion-induced time-varying corneal birefringence. In this article our group presents, for the first time, results that show dual-wavelength polarimetry can be used to accurately detect glucose concentrations in the presence of motion-induced birefringence in vivo using New Zealand White rabbits. In total, nine animal studies (three New Zealand White rabbits across three separate days) were conducted. Using the dual-wavelength optical polarimetric approach, in vivo, an overall mean average relative difference of 4.49% (11.66 mg/dL) was achieved with 100% Zone A+B hits on a Clarke error grid, including 100% falling in Zone A. The results indicate that dual-wavelength polarimetry can effectively be used to significantly reduce the noise due to time-varying corneal birefringence in vivo, allowing the accurate measurement of glucose concentration in the aqueous humor of the eye and correlating that with blood glucose.

  2. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    Science.gov (United States)

    Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-01

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  3. Exploiting the relationship between birefringence and force to measure airway smooth muscle contraction with PS-OCT (Conference Presentation)

    Science.gov (United States)

    Adams, David C.; Hariri, Lida P.; Holz, Jasmin A.; Szabari, Margit V.; Harris, R. Scott; Cho, Jocelyn L.; Hamilos, Daniel L.; Luster, Andrew D.; Medoff, Benjamin D.; Suter, Melissa J.

    2016-03-01

    The ability to observe airway dynamics is fundamental to forming a complete understanding of pulmonary diseases such as asthma. We have previously demonstrated that Optical Coherence Tomography (OCT) can be used to observe structural changes in the airway during bronchoconstriction, but standard OCT lacks the contrast to discriminate airway smooth muscle (ASM) bands- ASM being responsible for generating the force that drives airway constriction- from the surrounding tissue. Since ASM in general exhibits a greater degree of birefringence than the surrounding tissue, a potential solution to this problem lies in the implementation of polarization sensitivity (PS) to the OCT system. By modifying the OCT system so that it is sensitive to the birefringence of tissue under inspection, we can visualize the ASM with much greater clarity and definition. In this presentation we show that the force of contraction can be indirectly measured by an associated increase in the birefringence signal of the ASM. We validate this approach by attaching segments of swine trachea to an isometric force transducer and stimulating contraction, while simultaneously measuring the exerted force and imaging the segment with PS-OCT. We then show how our results may be used to extrapolate the force of contraction of closed airways in absence of additional measurement devices. We apply this technique to assess ASM contractility volumetrically and in vivo, in both asthmatic and non-asthmatic human volunteers.

  4. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, John P., E-mail: john.sutter@diamond.ac.uk; Dolbnya, Igor P.; Collins, Stephen P. [Diamond Light Source Ltd., Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Harris, Kenneth D. M.; Edwards-Gau, Gregory R. [School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales (United Kingdom); Palmer, Benjamin A. [Department of Structural Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001 (Israel)

    2015-04-28

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  5. Exploring vacuum birefringence based on a 100 PW laser and an x-ray free electron laser beam

    Science.gov (United States)

    Shen, Baifei; Bu, Zhigang; Xu, Jiancai; Xu, Tongjun; Ji, Liangliang; Li, Ruxin; Xu, Zhizhan

    2018-04-01

    Exploring vacuum birefringence with the station of extreme light at Shanghai Coherent Light Facility is considered. Laser pulses of intensity beyond 1023 W cm-2 are capable of polarizing the vacuum due to the ultra-strong electro-magnetic fields. The subtle difference of the vacuum refractive indexes along electric and magnetic fields leads to a birefringence effect for lights propagating through. The vacuum birefringence effect can now be captured by colliding a hard x-ray free electron laser (XFEL) beam with a high-power laser. The initial XFEL beam of pure linear polarization is predicated to gain a very small ellipticity after passing through the laser stimulated vacuum. Various interaction geometries are considered, showing that the estimated ellipticity lies between 1.8 × 10-10 and 10-9 for a 100 PW laser interacting with a 12.9 keV XFEL beam, approaching the threshold for todays’ polarity detection technique. The detailed experimental set-up is designed, including the polarimeter, the focusing compound refractive lens and the optical path. When taking into account the efficiencies of the x-ray instruments, it is found that about 10 polarization-flipped x-ray photons can be detected for a single shot for our design. Considering the background noise level, accumulating runs are necessary to obtain high confident measurement.

  6. Stable Trapping of Multielectron Helium Bubbles in a Paul Trap

    Science.gov (United States)

    Joseph, E. M.; Vadakkumbatt, V.; Pal, A.; Ghosh, A.

    2017-06-01

    In a recent experiment, we have used a linear Paul trap to store and study multielectron bubbles (MEBs) in liquid helium. MEBs have a charge-to-mass ratio (between 10^{-4} and 10^{-2} C/kg) which is several orders of magnitude smaller than ions (between 10^6 and 10^8 C/kg) studied in traditional ion traps. In addition, MEBs experience significant drag force while moving through the liquid. As a result, the experimental parameters for stable trapping of MEBs, such as magnitude and frequency of the applied electric fields, are very different from those used in typical ion trap experiments. The purpose of this paper is to model the motion of MEBs inside a linear Paul trap in liquid helium, determine the range of working parameters of the trap, and compare the results with experiments.

  7. Stokes-Mueller matrix polarimetry technique for circular dichroism/birefringence sensing with scattering effects.

    Science.gov (United States)

    Phan, Quoc-Hung; Lo, Yu-Lung

    2017-04-01

    A surface plasmon resonance (SPR)-enhanced method is proposed for measuring the circular dichroism (CD), circular birefringence (CB), and degree of polarization (DOP) of turbid media using a Stokes–Mueller matrix polarimetry technique. The validity of the analytical model is confirmed by means of numerical simulations. The simulation results show that the proposed detection method enables the CD and CB properties to be measured with a resolution of 10 ? 4 refractive index unit (RIU) and 10 ? 5 ?? RIU , respectively, for refractive indices in the range of 1.3 to 1.4. The practical feasibility of the proposed method is demonstrated by detecting the CB/CD/DOP properties of glucose–chlorophyllin compound samples containing polystyrene microspheres. It is shown that the extracted CB value decreases linearly with the glucose concentration, while the extracted CD value increases linearly with the chlorophyllin concentration. However, the DOP is insensitive to both the glucose concentration and the chlorophyllin concentration. Consequently, the potential of the proposed SPR-enhanced Stokes–Mueller matrix polarimetry method for high-resolution CB/CD/DOP detection is confirmed. Notably, in contrast to conventional SPR techniques designed to detect relative refractive index changes, the SPR technique proposed in the present study allows absolute measurements of the optical properties (CB/CD/DOP) to be obtained.

  8. Birefringence characteristics in sperm heads allow for the selection of reacted spermatozoa for intracytoplasmic sperm injection.

    Science.gov (United States)

    Gianaroli, Luca; Magli, M Cristina; Ferraretti, Anna P; Crippa, Andor; Lappi, Michela; Capitani, Serena; Baccetti, Baccio

    2010-02-01

    To verify clinical outcome after injection of spermatozoa that have undergone the acrosome reaction (reacted spermatozoa) vs. those still having an intact acrosome (nonreacted spermatozoa). Prospective, randomized study. Reproductive Medicine Unit, Italian Society for the Study of Reproductive Medicine, Bologna, Italy. According to a prospective randomization including 71 couples with severe male factor infertility, intracytoplasmic sperm injection (ICSI) was performed under polarized light that permitted analysis of the pattern of birefringence in the sperm head. Twenty-three patients had their oocytes injected with reacted spermatozoa, 26 patient's oocytes were injected with nonreacted spermatozoa, and in 22 patients both reacted and nonreacted spermatozoa were injected. Intracytoplasmic sperm injection was performed under polarized light to selectively inject acrosome-reacted and acrosome-nonreacted spermatozoa. Rates of fertilization, cleavage, pregnancy, implantation, and ongoing implantation. There was no effect on the fertilizing capacity and embryo development of either type of sperm, whereas the implantation rate was higher in oocytes injected with reacted spermatozoa (39.0%) vs. those injected with nonreacted spermatozoa (8.6%). The implantation rate was 24.4% in the group injected with both reacted and nonreacted spermatozoa. The delivery rate per cycle followed the same trend. Spermatozoa that have undergone the acrosome reaction seem to be more prone to supporting the development of viable ICSI embryos. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  9. Measurements of vacuum magnetic birefringence using permanent dipole magnets: the PVLAS experiment

    Science.gov (United States)

    Della Valle, F.; Gastaldi, U.; Messineo, G.; Milotti, E.; Pengo, R.; Piemontese, L.; Ruoso, G.; Zavattini, G.

    2013-05-01

    The PVLAS collaboration is presently assembling a new apparatus (at the INFN section of Ferrara, Italy) to detect vacuum magnetic birefringence (VMB). VMB is related to the structure of the quantum electrodynamics (QED) vacuum and is predicted by the Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by measuring the ellipticity acquired by a linearly polarized light beam propagating through a strong magnetic field. Using the very same optical technique it is also possible to search for hypothetical low-mass particles interacting with two photons, such as axion-like (ALP) or millicharged particles. Here we report the results of a scaled-down test setup and describe the new PVLAS apparatus. This latter is in construction and is based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity (>4 × 105) and two 0.8 m long 2.5 T rotating permanent dipole magnets. Measurements with the test setup have improved, by a factor 2, the previous upper bound on the parameter Ae, which determines the strength of the nonlinear terms in the QED Lagrangian: A(PVLAS)e < 3.3 × 10-21 T-2 at 95% c.l. Furthermore, new laboratory limits have been put on the inverse coupling constant of ALPs to two photons and confirmation of previous limits on the fractional charge of millicharged particles is given.

  10. Interrogation and mitigation of polarization effects for standard and birefringent FBGs

    Science.gov (United States)

    Ibrahim, Selwan K.; Van Roosbroeck, Jan; O'Dowd, John A.; Van Hoe, Bram; Lindner, Eric; Vlekken, Johan; Farnan, Martin; Karabacak, Devrez M.; Singer, Johannes M.

    2016-05-01

    Optical sensors based on Fiber Bragg Gratings (FBGs) are used in several applications and industries. Several inscription techniques and type of fibers can be used. However, depending on the writing process, type of fiber used and the packaging of the sensor a Polarization Dependent Frequency Shift (PDFS) can often be observed with polarized tunable laser based optical interrogators. Here we study the PDFS of the FBG peak for the different FBG types. A PDFS of 20pm was observed across the FBGs. To mitigate and reduce this effect we propose a polarization mitigation technique which relies on a synchronous polarization switch to reduce the effect typically by a factor greater than 4. In other scenarios the sensor itself is designed to be birefringent (Bi-FBG) to allow pressure and/or simultaneous temperature and strain measurements. Using the same polarization switch we demonstrate how we can interrogate the Bi-FBGs with high accuracy to enable high performance of such sensors to be achievable.

  11. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  12. Atom trap trace analysis

    International Nuclear Information System (INIS)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-01-01

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual 85 Kr and 81 Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10 -11 and 10 -13 , respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications

  13. Magnetic traps with a sperical separatrix: Tornado traps

    International Nuclear Information System (INIS)

    Peregood, B.P.; Lehnert, B.

    1979-11-01

    A review is given on the features of magnetic traps with a spherical separatrix, with special emphesis on Tornado spiral coil configurations. The confinement and heating of static plasmas in Tornado traps is treated, including the topology of the magnetic field structure, the magneto-mechanical properties of the magnetic coil system, as well as the particle orbits and plasma behaviour in these traps. In additio, the mode of rotating plasma operation by crossed electric and magnetic fields is being described. The results of experiments on static and rotating plasmas are summarized, and conclusions are drawn about future possibilities of Tornado traps for the creation and containment of hot plasmas. (author)

  14. Magnetic traps with a spherical separatrix: Tornado traps

    International Nuclear Information System (INIS)

    Peregood, B.P.; Lehnert, B.

    1981-01-01

    A review is given on the features of magnetic traps with a spherical separatrix, with special emphasis on Tornado spiral coil configurations. The confinement and heating of static plasms in Tornado traps is treated, including the topology of the magnetic field structure, the magneto-mechanical properties of the magnetic coil system, as well as the particle orbits and plasma behaviour in these traps. In addition, the mode of rotating plasma operation by crossed electric and magnetic fields is described. The results of experiments on static and rotating plasmas are summarized, and conclusions are drawn about future possibilities of Tornado traps in the creation and containment of hot plasmas. (orig.)

  15. Characteristics of trapped electrons and electron traps in single crystals

    International Nuclear Information System (INIS)

    Budzinski, E.E.; Potter, W.R.; Potienko, G.; Box, H.C.

    1979-01-01

    Two additional carbohydrates are reported whose crystal structures trap electrons intermolecularly in single crystals x irradiated at low temperature, namely sucrose and rhamnose. Five carbohydrate and polyhydroxy compounds are now known which exhibit this phenomenon. The following characteristics of the phenomenon were investigated: (1) the hyperfine couplings of the electron with protons of the polarized hydroxy groups forming the trap; (2) the distances between these protons and the trapped electron; (3) the spin density of the electron at the protons and (4) the relative stabilities of the electron trapped in various crystal structures

  16. ATRAP - Progress Towards Trapped Antihydrogen

    International Nuclear Information System (INIS)

    Grzonka, D.; Goldenbaum, F.; Oelert, W.; Sefzick, T.; Zhang, Z.; Comeau, D.; Hessels, E.A.; Storry, C.H.; Gabrielse, G.; Larochelle, P.; Lesage, D.; Levitt, B.; Speck, A.; Haensch, T.W.; Pittner, H.; Walz, J.

    2005-01-01

    The ATRAP experiment at the CERN antiproton decelerator AD aims for a test of the CPT invariance by a high precision comparison of the 1s-2s transition in the hydrogen and the antihydrogen atom.Antihydrogen production is routinely operated at ATRAP and detailed studies have been performed in order to optimize the production efficiency of useful antihydrogen.For high precision measurements of atomic transitions cold antihydrogen in the ground state is required which must be trapped due to the low number of available antihydrogen atoms compared to the cold hydrogen beam used for hydrogen spectroscopy. To ensure a reasonable antihydrogen trapping efficiency a magnetic trap has to be superposed the nested Penning trap. First trapping tests of charged particles within a combined magnetic/Penning trap have started at ATRAP

  17. ATRAP Progress Towards Trapped Antihydrogen

    CERN Document Server

    Grzonka, D; Gabrielse, G; Goldenbaum, F; Hänsch, T W; Hessels, E A; Larochelle, P; Le Sage, D; Levitt, B; Oelert, W; Pittner, H; Sefzick, T; Speck, A; Storry, C H; Walz, J; Zhang, Z

    2005-01-01

    The ATRAP experiment at the CERN antiproton decelerator AD aims for a test of the CPT invariance by a high precision comparison of the 1s‐2s transition in the hydrogen and the antihydrogen atom. Antihydrogen production is routinely operated at ATRAP and detailed studies have been performed in order to optimize the production efficiency of useful antihydrogen. For high precision measurements of atomic transitions cold antihydrogen in the ground state is required which must be trapped due to the low number of available antihydrogen atoms compared to the cold hydrogen beam used for hydrogen spectroscopy. To ensure a reasonable antihydrogen trapping efficiency a magnetic trap has to be superposed the nested Penning trap. First trapping tests of charged particles within a combined magnetic/Penning trap have started at ATRAP.

  18. The effect of non-sphericity on mass and anisotropy measurements in dSph galaxies with Schwarzschild method

    Science.gov (United States)

    Kowalczyk, Klaudia; Łokas, Ewa L.; Valluri, Monica

    2018-05-01

    In our previous work we confirmed the reliability of the spherically symmetric Schwarzschild orbit-superposition method to recover the mass and velocity anisotropy profiles of spherical dwarf galaxies. Here, we investigate the effect of its application to intrinsically non-spherical objects. For this purpose we use a model of a dwarf spheroidal galaxy formed in a numerical simulation of a major merger of two discy dwarfs. The shape of the stellar component of the merger remnant is axisymmetric and prolate which allows us to identify and measure the bias caused by observing the spheroidal galaxy along different directions, especially the longest and shortest principal axis. The modelling is based on mock data generated from the remnant that are observationally available for dwarfs: projected positions and line-of-sight velocities of the stars. In order to obtain a reliable tool while keeping the number of parameters low we parametrize the total mass distribution as a radius-dependent mass-to-light ratio with just two free parameters we aim to constrain. Our study shows that if the total density profile is known, the true, radially increasing anisotropy profile can be well recovered for the observations along the longest axis whereas the data along the shortest axis lead to the inference of an incorrect, isotropic model. On the other hand, if the density profile is derived from the method as well, the anisotropy is always underestimated but the total mass profile is well recovered for the data along the shortest axis whereas for the longest axis the mass content is overestimated.

  19. MRI Assessment of Uterine Artery Patency and Fibroid Infarction Rates 6 Months after Uterine Artery Embolization with Nonspherical Polyvinyl Alcohol

    International Nuclear Information System (INIS)

    Das, Raj; Gonsalves, Michael; Vlahos, Ioannis; Manyonda, Issac; Belli, Anna-Maria

    2013-01-01

    Purpose: We have observed significant rates of uterine artery patency after uterine artery embolization (UAE) with nonspherical polyvinyl alcohol (nsPVA) on 6 month follow-up MR scanning. The study aim was to quantitatively assess uterine artery patency after UAE with nsPVA and to assess the effect of continued uterine artery patency on outcomes. Methods: A single centre, retrospective study of 50 patients undergoing bilateral UAE for uterine leiomyomata was undertaken. Pelvic MRI was performed before and 6 months after UAE. All embolizations were performed with nsPVA. Outcome measures included uterine artery patency, uterine and dominant fibroid volume, dominant fibroid percentage infarction, presence of ovarian arterial collaterals, and symptom scores assessed by the Uterine Fibroid Symptom and Quality of Life questionnaire (UFS-QOL). Results: Magnetic resonance angiographic evidence of uterine artery recanalization was demonstrated in 90 % of the patients (64 % bilateral, 26 % unilateral) at 6 months. Eighty percent of all dominant fibroids demonstrated >90 % infarction. The mean percentage reduction in dominant fibroid volume was 35 %. No significant difference was identified between nonpatent, unilateral, and bilateral recanalization of the uterine arteries with regard to percentage dominant fibroid infarction or dominant fibroid volume reduction. The presence of bilaterally or unilaterally patent uterine arteries was not associated with inferior clinical outcomes (symptom score or UFS-QOL scores) at 6 months. Conclusion: The high rates of uterine artery patency challenge the current paradigm that nsPVA is a permanent embolic agent and that permanent uterine artery occlusion is necessary to optimally treat uterine fibroids. Despite high rates of uterine artery recanalization in this cohort, satisfactory fibroid infarction rates and UFS-QOL scores were achieved

  20. MRI Assessment of Uterine Artery Patency and Fibroid Infarction Rates 6 Months after Uterine Artery Embolization with Nonspherical Polyvinyl Alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Das, Raj, E-mail: rajdas@nhs.net; Gonsalves, Michael; Vlahos, Ioannis [St George' s Healthcare NHS Trust, Blackshaw, Department of Radiology (United Kingdom); Manyonda, Issac [St George' s Healthcare NHS Trust, Department of Gynaecology (United Kingdom); Belli, Anna-Maria [St George' s Healthcare NHS Trust, Blackshaw, Department of Radiology (United Kingdom)

    2013-10-15

    Purpose: We have observed significant rates of uterine artery patency after uterine artery embolization (UAE) with nonspherical polyvinyl alcohol (nsPVA) on 6 month follow-up MR scanning. The study aim was to quantitatively assess uterine artery patency after UAE with nsPVA and to assess the effect of continued uterine artery patency on outcomes. Methods: A single centre, retrospective study of 50 patients undergoing bilateral UAE for uterine leiomyomata was undertaken. Pelvic MRI was performed before and 6 months after UAE. All embolizations were performed with nsPVA. Outcome measures included uterine artery patency, uterine and dominant fibroid volume, dominant fibroid percentage infarction, presence of ovarian arterial collaterals, and symptom scores assessed by the Uterine Fibroid Symptom and Quality of Life questionnaire (UFS-QOL). Results: Magnetic resonance angiographic evidence of uterine artery recanalization was demonstrated in 90 % of the patients (64 % bilateral, 26 % unilateral) at 6 months. Eighty percent of all dominant fibroids demonstrated >90 % infarction. The mean percentage reduction in dominant fibroid volume was 35 %. No significant difference was identified between nonpatent, unilateral, and bilateral recanalization of the uterine arteries with regard to percentage dominant fibroid infarction or dominant fibroid volume reduction. The presence of bilaterally or unilaterally patent uterine arteries was not associated with inferior clinical outcomes (symptom score or UFS-QOL scores) at 6 months. Conclusion: The high rates of uterine artery patency challenge the current paradigm that nsPVA is a permanent embolic agent and that permanent uterine artery occlusion is necessary to optimally treat uterine fibroids. Despite high rates of uterine artery recanalization in this cohort, satisfactory fibroid infarction rates and UFS-QOL scores were achieved.

  1. On the impact of non-sphericity and small-scale surface roughness on the optical properties of hematite aerosols

    International Nuclear Information System (INIS)

    Kahnert, Michael; Nousiainen, Timo; Mauno, Paeivi

    2011-01-01

    We perform a comparative modelling study to investigate how different morphological features influence the optical properties of hematite aerosols. We consider high-order Chebyshev particles as a proxy for aerosol with a small-scale surface roughness, and spheroids as a model for nonspherical aerosols with a smooth boundary surface. The modelling results are compared to those obtained for homogeneous spherical particles. It is found that for hematite particles with an absorption efficiency of order unity the difference in optical properties between spheres and spheroids disappears. For optically softer particles, such as ice particles at far-infrared wavelengths, this effect can be observed for absorption efficiencies lower than unity. The convergence of the optical properties of spheres and spheroids is caused by absorption and quenching of internal resonances inside the particles, which depend both on the imaginary part of the refractive index and on the size parameter, and to some extent on the real part of the refractive index. By contrast, small-scale surface roughness becomes the dominant morphological feature for large particles. This effect is likely to depend on the amplitude of the surface roughness, the relative significance of internal resonances, and possibly on the real part of the refractive index. The extinction cross section is rather insensitive to surface roughness, while the single-scattering albedo, asymmetry parameter, and the Mueller matrix are strongly influenced. Small-scale surface roughness reduces the backscattering cross section by up to a factor of 2-3 as compared to size-equivalent particles with a smooth boundary surface. This can have important implications for the interpretation of lidar backscattering observations.

  2. Calibration of optically trapped nanotools

    Energy Technology Data Exchange (ETDEWEB)

    Carberry, D M; Simpson, S H; Grieve, J A; Hanna, S; Miles, M J [H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Wang, Y; Schaefer, H; Steinhart, M [Institute for Chemistry, University of Osnabrueck, Osnabrueck (Germany); Bowman, R; Gibson, G M; Padgett, M J, E-mail: m.j.miles@bristol.ac.uk [SUPA, Department of Physics and Astronomy, University of Glasgow, Science Road, Glasgow G12 8QQ (United Kingdom)

    2010-04-30

    Holographically trapped nanotools can be used in a novel form of force microscopy. By measuring the displacement of the tool in the optical traps, the contact force experienced by the probe can be inferred. In the following paper we experimentally demonstrate the calibration of such a device and show that its behaviour is independent of small changes in the relative position of the optical traps. Furthermore, we explore more general aspects of the thermal motion of the tool.

  3. Optical traps with geometric aberrations

    International Nuclear Information System (INIS)

    Roichman, Yael; Waldron, Alex; Gardel, Emily; Grier, David G.

    2006-01-01

    We assess the influence of geometric aberrations on the in-plane performance of optical traps by studying the dynamics of trapped colloidal spheres in deliberately distorted holographic optical tweezers. The lateral stiffness of the traps turns out to be insensitive to moderate amounts of coma, astigmatism, and spherical aberration. Moreover holographic aberration correction enables us to compensate inherent shortcomings in the optical train, thereby adaptively improving its performance. We also demonstrate the effects of geometric aberrations on the intensity profiles of optical vortices, whose readily measured deformations suggest a method for rapidly estimating and correcting geometric aberrations in holographic trapping systems

  4. Trapping, manipulation and rapid rotation of NBD-C8 fluorescent single microcrystals in optical tweezers

    International Nuclear Information System (INIS)

    GALAUP, Jean-Pierre; RODRIGUEZ-OTAZO, Mariela; AUGIER-CALDERIN, Angel; LAMERE; Jean-Francois; FERY-FORGUES, Suzanne

    2009-01-01

    We have built an optical tweezers experiment based on an inverted microscope to trap and manipulate single crystals of micro or sub-micrometer size made from fluorescent molecules of 4-octylamino-7-nitrobenzoxadiazole (NBD-C8). These single crystals have parallelepiped shapes and exhibit birefringence properties evidenced through optical experiments between crossed polarizers in a polarizing microscope. The crystals are uniaxial with their optical axis oriented along their largest dimension. Trapped in the optical trap, the organic micro-crystals are oriented in such a way that their long axis is along the direction of the beam propagation, and their short axis follows the direction of the linear polarization. Therefore, with linearly polarized light, simply rotating the light polarization can orient the crystal. When using circularly or only elliptically polarized light, the crystal can spontaneously rotate and reach rotation speed of several hundreds of turns per second. A surprising result has been observed: when the incident power is growing up, the rotation speed increases to reach a maximum value and then decreases even when the power is still growing up. Moreover, this evolution is irreversible. Different possible explanations can be considered. The development of a 3D control of the crystals by dynamical holography using liquid crystal spatial modulators will be presented and discussed on the basis of the most recent results obtained. (Author)

  5. A live-trap and trapping technique for fossorial mammals

    African Journals Online (AJOL)

    mammals. G.C. Hickman. An effective live-trap was designed for Cryptomys hottentotus .... that there is an animal in the burrow system, and to lessen the likelihood of the .... the further testing and modification of existing trap types. Not only is it ...

  6. Electron traps in semiconducting polymers : Exponential versus Gaussian trap distribution

    NARCIS (Netherlands)

    Nicolai, H. T.; Mandoc, M. M.; Blom, P. W. M.

    2011-01-01

    The low electron currents in poly(dialkoxy-p-phenylene vinylene) (PPV) derivatives and their steep voltage dependence are generally explained by trap-limited conduction in the presence of an exponential trap distribution. Here we demonstrate that the electron transport of several PPV derivatives can

  7. Electron traps in semiconducting polymers: exponential versus Gaussian trap distribution

    NARCIS (Netherlands)

    Nicolai, H.T.; Mandoc, M.M.; Blom, P.W.M.

    2011-01-01

    The low electron currents in poly(dialkoxy-p-phenylene vinylene) (PPV) derivatives and their steep voltage dependence are generally explained by trap-limited conduction in the presence of an exponential trap distribution. Here we demonstrate that the electron transport of several PPV derivatives can

  8. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  9. Detection of trapped antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Hydomako, Richard [Calgary Univ., AB (Canada). Dept. of Physics and Astronomy

    2013-02-01

    A landmark thesis describing the first ever trapping of antihydrogen atoms in CERN's ALPHA apparatus. Opens the way to crucial tests of fundamental theories. Nominated as an outstanding contribution by the University of Calgary. In 2010, the ALPHA collaboration achieved a first for mankind: the stable, long-term storage of atomic antimatter, a project carried out a the Antiproton Decelerator facility at CERN. A crucial element of this observation was a dedicated silicon vertexing detector used to identify and analyze antihydrogen annihilations. This thesis reports the methods used to reconstruct the annihilation location. Specifically, the methods used to identify and extrapolate charged particle tracks and estimate the originating annihilation location are outlined. Finally, the experimental results demonstrating the first-ever magnetic confinement of antihydrogen atoms are presented. These results rely heavily on the silicon detector, and as such, the role of the annihilation vertex reconstruction is emphasized.

  10. Birefringence Bragg Binary (3B) grating, quasi-Bragg grating and immersion gratings

    Science.gov (United States)

    Ebizuka, Noboru; Morita, Shin-ya; Yamagata, Yutaka; Sasaki, Minoru; Bianco, Andorea; Tanabe, Ayano; Hashimoto, Nobuyuki; Hirahara, Yasuhiro; Aoki, Wako

    2014-07-01

    A volume phase holographic (VPH) grating achieves high angular dispersion and very high diffraction efficiency for the first diffraction order and for S or P polarization. However the VPH grating could not achieve high diffraction efficiency for non-polarized light at a large diffraction angle because properties of diffraction efficiencies for S and P polarizations are different. Furthermore diffraction efficiency of the VPH grating extinguishes toward a higher diffraction order. A birefringence binary Bragg (3B) grating is a thick transmission grating with optically anisotropic material such as lithium niobate or liquid crystal. The 3B grating achieves diffraction efficiency up to 100% for non-polarized light by tuning of refractive indices for S and P polarizations, even in higher diffraction orders. We fabricated 3B grating with liquid crystal and evaluated the performance of the liquid crystal grating. A quasi-Bragg (QB) grating, which consists long rectangle mirrors aligned in parallel precisely such as a window shade, also achieves high diffraction efficiency toward higher orders. We fabricated QB grating by laminating of silica glass substrates and glued by pressure fusion of gold films. A quasi-Bragg immersion (QBI) grating has smooth mirror hypotenuse and reflector array inside the hypotenuse, instead of step-like grooves of a conventional immersion grating. An incident beam of the QBI grating reflects obliquely at a reflector, then reflects vertically at the mirror surface and reflects again at the same reflector. We are going to fabricate QBI gratings by laminating of mirror plates as similar to fabrication of the QB grating. We will also fabricate silicon and germanium immersion gratings with conventional step-like grooves by means of the latest diamond machining methods. We introduce characteristics and performance of these gratings.

  11. The Microwave Radiative Properties of Falling Snow Derived from Nonspherical Ice Particle Models. Part II: Initial Testing Using Radar, Radiometer and In Situ Observations

    Science.gov (United States)

    Olson, William S.; Tian, Lin; Grecu, Mircea; Kuo, Kwo-Sen; Johnson, Benjamin; Heymsfield, Andrew J.; Bansemer, Aaron; Heymsfield, Gerald M.; Wang, James R.; Meneghini, Robert

    2016-01-01

    In this study, two different particle models describing the structure and electromagnetic properties of snow are developed and evaluated for potential use in satellite combined radar-radiometer precipitation estimation algorithms. In the first model, snow particles are assumed to be homogeneous ice-air spheres with single-scattering properties derived from Mie theory. In the second model, snow particles are created by simulating the self-collection of pristine ice crystals into aggregate particles of different sizes, using different numbers and habits of the collected component crystals. Single-scattering properties of the resulting nonspherical snow particles are determined using the discrete dipole approximation. The size-distribution-integrated scattering properties of the spherical and nonspherical snow particles are incorporated into a dual-wavelength radar profiling algorithm that is applied to 14- and 34-GHz observations of stratiform precipitation from the ER-2 aircraft-borne High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) radar. The retrieved ice precipitation profiles are then input to a forward radiative transfer calculation in an attempt to simulate coincident radiance observations from the Conical Scanning Millimeter-Wave Imaging Radiometer (CoSMIR). Much greater consistency between the simulated and observed CoSMIR radiances is obtained using estimated profiles that are based upon the nonspherical crystal/aggregate snow particle model. Despite this greater consistency, there remain some discrepancies between the higher moments of the HIWRAP-retrieved precipitation size distributions and in situ distributions derived from microphysics probe observations obtained from Citation aircraft underflights of the ER-2. These discrepancies can only be eliminated if a subset of lower-density crystal/aggregate snow particles is assumed in the radar algorithm and in the interpretation of the in situ data.

  12. Scattering by non-spherical particles of size comparable to a wavelength - A new semi-empirical theory. [atmospheric radiative transfer

    Science.gov (United States)

    Pollack, J. B.; Cuzzi, J. N.

    1978-01-01

    Mie theory, which is generally used to describe the scattering behavior of particles at a certain wavelength, is only rigorously correct for spherical particles. Particles found as atmospheric constituents, with the exception of cloud droplets, are, however, decidedly nonspherical. An investigation is, therefore, conducted regarding the significant ways in which the scattering behavior of irregularly shaped particles differs from that of spheres. A systematic method is formulated for treating the real scalar scattering behavior. A description is presented of a new semiempirical theory based on simple physical principles and data obtained in laboratory measurements, which successfully reproduces the single scattering phase function for a wide range of particle shapes, sizes, and refractive indices.

  13. Flux trapping in superconducting cavities

    International Nuclear Information System (INIS)

    Vallet, C.; Bolore, M.; Bonin, B.; Charrier, J.P.; Daillant, B.; Gratadour, J.; Koechlin, F.; Safa, H.

    1992-01-01

    The flux trapped in various field cooled Nb and Pb samples has been measured. For ambient fields smaller than 3 Gauss, 100% of the flux is trapped. The consequences of this result on the behavior of superconducting RF cavities are discussed. (author) 12 refs.; 2 figs

  14. Injection into electron plasma traps

    International Nuclear Information System (INIS)

    Gorgadze, Vladimir; Pasquini, Thomas A.; Fajans, Joel; Wurtele, Jonathan S.

    2003-01-01

    Computational studies and experimental measurements of plasma injection into a Malmberg-Penning trap reveal that the number of trapped particles can be an order of magnitude higher than predicted by a simple estimates based on a ballistic trapping model. Enhanced trapping is associated with a rich nonlinear dynamics generated by the space-charge forces of the evolving trapped electron density. A particle-in-cell simulation is used to identify the physical mechanisms that lead to the increase in trapped electrons. The simulations initially show strong two-stream interactions between the electrons emitted from the cathode and those reflected off the end plug of the trap. This is followed by virtual cathode oscillations near the injection region. As electrons are trapped, the initially hollow longitudinal phase-space is filled, and the transverse radial density profile evolves so that the plasma potential matches that of the cathode. Simple theoretical arguments are given that describe the different dynamical regimes. Good agreement is found between simulation and theory

  15. The ALPHA antihydrogen trapping apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Andresen, G.B. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M.D. [Department of Physics, Simon Fraser University, Burnaby, BC Canada, V5A 1S6 (Canada); Baquero-Ruiz, M. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Bertsche, W. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); The Cockcroft Institute, Warrington WA4 4AD (United Kingdom); Bowe, P.D. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Butler, E. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Capra, A. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Carpenter, P.T. [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States); Cesar, C.L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Chapman, S. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Charlton, M.; Deller, A.; Eriksson, S. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Escallier, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Fajans, J. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Friesen, T. [Department of Physics and Astronomy, University of Calgary, Calgary AB, Canada, T2N 1N4 (Canada); Fujiwara, M.C.; Gill, D.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver BC, Canada V6T 2A3 (Canada); Gutierrez, A. [Department of Physics and Astronomy, University of British Columbia, Vancouver BC, Canada V6T 1Z4 (Canada); and others

    2014-01-21

    The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved.

  16. Electromagnetic trapping of neutral atoms

    International Nuclear Information System (INIS)

    Metcalf, H.J.

    1986-01-01

    Cooling and trapping of neutral atoms is a new branch of applied physics that has potential for application in many areas. The authors present an introduction to laser cooling and magnetic trapping. Some basic ideas and fundamental limitations are discussed, and the first successful experiments are reviewed. Trapping a neutral object depends on the interaction between an inhomogeneous electromagnetic field and a multiple moment that results in the exchange of kinetic for potential energy. In neutral atom traps, the potential energy must be stored as internal atomic energy, resulting in two immediate and extremely important consequences. First, the atomic energy levels will necessarily shift as the atoms move in the trap, and, second, practical traps for ground state neutral atoms atr necessarily very shallow compared to thermal energy. This small depth also dictates stringent vacuum requirements because a trapped atom cannot survive a single collision with a thermal energy background gas molecule. Neutral trapping, therefore, depends on substantial cooling of a thermal atomic sample and is inextricably connected with the cooling process

  17. Quantum computing with trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.

    1998-01-01

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  18. Trapped surfaces in spherical stars

    International Nuclear Information System (INIS)

    Bizon, P.; Malec, E.; O'Murchadha, N.

    1988-01-01

    We give necessary and sufficient conditions for the existence of trapped surfaces in spherically symmetric spacetimes. These conditions show that the formation of trapped surfaces depends on both the degree of concentration and the average flow of the matter. The result can be considered as a partial validation of the cosmic-censorship hypothesis

  19. Spin resonance with trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E [Institut fuer Laser-Physik, Universitaet Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany)

    2003-03-14

    A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped {sup 171}Yb{sup +}, we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states.

  20. Spin resonance with trapped ions

    International Nuclear Information System (INIS)

    Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E

    2003-01-01

    A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped 171 Yb + , we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states

  1. Host inflammatory response to polypropylene implants: insights from a quantitative immunohistochemical and birefringence analysis in a rat subcutaneous model

    Directory of Open Access Journals (Sweden)

    Alessandro Prudente

    2016-06-01

    Full Text Available ABSTRACT Objectives To describe acute and sub acute aspects of histological and immunohistochemical response to PP implant in a rat subcutaneous model based on objective methods. Materials and Methods Thirty rats had a PP mesh subcutaneously implanted and the same dissection on the other side of abdomen but without mesh (sham. The animals were euthanized after 4 and 30 days. Six slides were prepared using the tissue removed: one stained with hematoxylin-eosin (inflammation assessment; one unstained (birefringence evaluation and four slides for immunohistochemical processing: IL-1 and TNF-α (pro-inflammatory cytokines, MMP-2 (collagen metabolism and CD-31 (angiogenesis. The area of inflammation, the birefringence index, the area of immunoreactivity and the number of vessels were objectively measured. Results A larger area of inflammatory reaction was observed in PP compared to sham on the 4th and on the 30th day (p=0.0002. After 4 days, PP presented higher TNF (p=0.0001 immunoreactivity than sham and no differences were observed in MMP-2 (p=0.06 and IL-1 (p=0.08. After 30 days, a reduction of IL-1 (p=0.010 and TNF (p=0.016 for PP and of IL-1 (p=0.010 for sham were observed. Moreover, area of MMP-2 immunoreactivity decreased over time for PP group (p=0.018. Birefringence index and vessel counting showed no differences between PP and sham (p=0.27 and p=0.58, respectively. Conclusions The implantation of monofilament and macroporous polypropylene in the subcutaneous of rats resulted in increased inflammatory activity and higher TNF production in the early post implant phase. After 30 days, PP has similar cytokines immunoreactivity, vessel density and extracellular matrix organization.

  2. Radially polarized and passively Q-switched Yb-doped fiber laser based on intracavity birefringent mode discrimination

    Science.gov (United States)

    Sun, Xuehuan; Wu, Yongxiao; Chen, Sanbin; Li, Jianlang

    2018-05-01

    In this paper, we demonstrated a passive Q-switched ytterbium-doped fiber laser with radially polarized beam emission by using a c-cut YVO4 birefringent crystal as the intracavity polarization discriminator, and a Cr4+:YAG crystal as the saturable absorber and output coupler. The maximum averaged laser power reached 3.89 W with a high slope efficiency of 66.5%. The laser pulse had a peak power of 161 W, 160 ns duration, and 151 kHz repetition rate at the absorbed pump power of 6.48 W. Such a radially polarized pulse would facilitate numerous applications.

  3. Flow above and within granular media composed of spherical and non-spherical particles - using a 3D numerical model

    Science.gov (United States)

    Bartzke, Gerhard; Kuhlmann, Jannis; Huhn, Katrin

    2016-04-01

    the flow into and within a granular medium composed of spherical and non-spherical shapes under wave forcing. It is concluded that variations in grain shape orientation within a bed appear to control the amount of flow that can be accumulated by the pores, which was illustrated in a conceptual model.

  4. Investigation of the surface terminations of icosahedral AlPdMn quasicrystal based on a modified non-spherical model

    International Nuclear Information System (INIS)

    Yu Fengmei; Zou Huamin; Wang Jianbo; Wang Renhui

    2004-01-01

    The atomic positions are obtained from a modified non-spherical model of icosahedral AlPdMn quasicrystal (Fang et al 2003 J. Phys.: Condens. Matter 15 4947) by the cut method. The four-shell pseudo-Mackay clusters (PMCs) were searched for in a box of 400 A x 400 A x 400 A. The results show that the number of atoms in the fourth shell, an icosidodecahedron, of the pseudo-Mackay cluster can vary from 15 to 30 because of the cluster overlap, and about 99.96% of the total atoms are included in such incomplete pseudo-Mackay clusters. The characteristics of the atom distribution in the planes perpendicular to a fivefold axis indicate that the planes, which are 1.56 A apart from their neighbouring planes, are expected to be the terminal surfaces. If one such a plane and its closest neighbouring plane, between which the spacing is 0.48 A, are considered as a thin layer or a corrugated surface, these layers are also the layers with the maximum density. The pair of corrugated surfaces that are 1.56 A apart have almost identical chemical composition. These planes form terraces that follow the rule of the Fibonacci sequence with two step heights, 6.60 and 4.08 A. On the corrugated surfaces perpendicular to a fivefold axis the pentagonal holes arise from the interspaces of adjacent incomplete PMCs. For the atomic planes normal to a twofold axis, the planes with spacing of 1.48 A from their adjacent planes might be expected to be the terminal surfaces, which form terraces with step heights of 6.28 and 3.88 A following the rule of the Fibonacci sequence. For the atomic planes normal to a threefold axis, the planes with spacing of 0.86 A from their adjacent planes might be expected to be the terminal surfaces. No similar results were found for the atomic layers perpendicular to a pseudo-twofold axis

  5. Integrated fiber-mirror ion trap for strong ion-cavity coupling

    International Nuclear Information System (INIS)

    Brandstätter, B.; Schüppert, K.; Casabone, B.; Friebe, K.; Stute, A.; Northup, T. E.; McClung, A.; Schmidt, P. O.; Deutsch, C.; Reichel, J.; Blatt, R.

    2013-01-01

    We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 μm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate

  6. Trapping tsetse flies on water

    Directory of Open Access Journals (Sweden)

    Laveissière C.

    2011-05-01

    Full Text Available Riverine tsetse flies such as Glossina palpalis gambiensis and G. tachinoides are the vectors of human and animal trypanosomoses in West Africa. Despite intimate links between tsetse and water, to our knowledge there has never been any attempt to design trapping devices that would catch tsetse on water. In mangrove (Guinea one challenging issue is the tide, because height above the ground for a trap is a key factor affecting tsetse catches. The trap was mounted on the remains of an old wooden dugout, and attached with rope to nearby branches, thereby allowing it to rise and fall with the tide. Catches showed a very high density of 93.9 flies/”water-trap”/day, which was significantly higher (p < 0.05 than all the catches from other habitats where the classical trap had been used. In savannah, on the Comoe river of South Burkina Faso, the biconical trap was mounted on a small wooden raft anchored to a stone, and catches were compared with the classical biconical trap put on the shores. G. p. gambiensis and G. tachinoides densities were not significantly different from those from the classical biconical one. The adaptations described here have allowed to efficiently catch tsetse on the water, which to our knowledge is reported here for the first time. This represents a great progress and opens new opportunities to undertake studies on the vectors of trypanosomoses in mangrove areas of Guinea, which are currently the areas showing the highest prevalences of sleeping sickness in West Africa. It also has huge potential for tsetse control using insecticide impregnated traps in savannah areas where traps become less efficient in rainy season. The Guinean National control programme has already expressed its willingness to use such modified traps in its control campaigns in Guinea, as has the national PATTEC programme in Burkina Faso during rainy season.

  7. Status of THe-Trap

    Energy Technology Data Exchange (ETDEWEB)

    Streubel, Sebastian; Eronen, Tommi; Hoecker, Martin; Ketter, Jochen; Blaum, Klaus [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Van Dyck, Robert S. Jr. [Department of Physics, University of Washington, Seattle, WA (United States)

    2013-07-01

    THe-Trap (short for Tritium-{sup 3}He Trap) is a Penning-trap setup dedicated to measure the {sup 3}H to {sup 3}He mass-ratio with a relative uncertainty of better than 10{sup -11}. The ratio is of relevance for the KArlsruhe TRItium Neutrino experiment (KATRIN), which aims to measure the electron anti-neutrino mass, by measuring the shape of the β-decay energy spectrum close to its endpoint. An independent measurement of the {sup 3}H to {sup 3}He mass-ratio pins down this endpoint, and thus will help to determine the systematics of KATRIN. The trap setup consists of two Penning-traps: One trap for precision measurements, the other trap for ion storage. Ideally, the trap content will be periodically switched, which reduces the time between the measurements of the two ions' motional frequencies. In 2012, a mass ratio measurement of {sup 12}C{sup 4+} to {sup 14}N{sup 5+} was performed to characterize systematic effects of the traps. This measurement yielded a accuracy of 10{sup -9}. Further investigations revealed that a major reason for the modest accuracy is the large axial amplitude of ∼100 μm, compared to a ideal case of 3 μm at 4 K. In addition, relative magnetic fluctuations at a 3 x 10{sup -10} level on a 10 h timescale need to be significantly improved. In this contribution, the aforementioned findings and further systematic studies will be presented.

  8. A new approach to polarimetric measurements based on birefringent crystals and diode lasers

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Lívia Paulia Dias; Rohwedder, Jarbas José Rodrigues [Chemistry Institute, Department of Analytical Chemistry, UNICAMP, Caixa Postal 6154, CEP: 13087-971 Campinas, SP (Brazil); Pasquini, Celio, E-mail: pasquini@iqm.unicamp.br [Chemistry Institute, Department of Analytical Chemistry, UNICAMP, Caixa Postal 6154, CEP: 13087-971 Campinas, SP (Brazil)

    2013-04-10

    Highlights: ► New approach to polarimetric measurements is evaluated. ► A robust, with no mechanical moving parts polarimeter is presented. ► The performance of the instrument was evaluated for saccharimetric measurements. ► The uncertainty of the instrument was evaluated as a function of the measured angle. ► Polarimeter allow the use of low cost lasers while obtaining precision as good as 0.003°. -- Abstract: A new polarimetric instrument and measurement method is described based on the use of diode lasers as radiation source (532, 650 and 1064 nm) and birefringent prisms, such as Glan-Laser and Wollaston, as analyzers. The laser radiation is passed through a dichroic polarizer film for further orientation of its polarization plane at 45° in relation to the polarization plane of the analyzer. The polarized beam, oriented in that way, passes the sample cell, impinges the prism surface, and the intensities of the two emerged beams are detected by two twin silicon detectors. Ideally, in the absence of any optically active substances, the crystals produces two orthogonally polarized refracted beams of equal intensity. In the presence of an optically active substance, the arctangent of the square root of the beam intensities ratio is equal to the new polarization angle (β) of the laser beam. The rotation angle imposed for any optically active substance present in the sample cell is then given by: α = (45 – β)°. Because the rotation is obtained by the ratio of the intensities of two beams, it is independent of the laser intensity, which can vary up to ±15% with no significant effect on the accuracy of the polarimetric measurement. The instrument has been evaluated for measurement of optically active substances such as sucrose and fructose. The instrument employs low cost components, is capable of attaining a repeatability of ±0.003° and can measure the rotation angle, over a ±45° range, in less than 2 s. Because it does not present any moving

  9. A reservoir trap for antiprotons

    CERN Document Server

    Smorra, Christian; Franke, Kurt; Nagahama, Hiroki; Schneider, Georg; Higuchi, Takashi; Van Gorp, Simon; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Yamazaki, Yasunori; Ulmer, Stefan

    2015-01-01

    We have developed techniques to extract arbitrary fractions of antiprotons from an accumulated reservoir, and to inject them into a Penning-trap system for high-precision measurements. In our trap-system antiproton storage times > 1.08 years are estimated. The device is fail-safe against power-cuts of up to 10 hours. This makes our planned comparisons of the fundamental properties of protons and antiprotons independent from accelerator cycles, and will enable us to perform experiments during long accelerator shutdown periods when background magnetic noise is low. The demonstrated scheme has the potential to be applied in many other precision Penning trap experiments dealing with exotic particles.

  10. Model and Simulation of a Tunable Birefringent Fiber Using Capillaries Filled with Liquid Ethanol for Magnetic Quasiphase Matching In-Fiber Isolator

    Directory of Open Access Journals (Sweden)

    Clint Zeringue

    2010-01-01

    Full Text Available A technique to tune a magnetic quasi-phase matching in-fiber isolator through the application of stress induced by two mutually orthogonal capillary tubes filled with liquid ethanol is investigated numerically. The results show that it is possible to “tune” the birefringence in these fibers over a limited range depending on the temperature at which the ethanol is loaded into the capillaries. Over this tuning range, the thermal sensitivity of the birefringence is an order-of-magnitude lower than conventional fibers, making this technique well suited for magnetic quasi-phase matching.

  11. Birefringence imaging of phase transitions: application to Na0.5Bi0.5TiO3

    International Nuclear Information System (INIS)

    Geday, M.; Kreisel, J.; Glazer, A.M.; Roleder, K.

    2000-01-01

    In recent years a number of imaging techniques to determine the optical properties of materials, either in reflection or in transmission, have been developed. Here the use of an imaging version of the so-called rotating-polarizer method in the study of phase transformations in crystals is demonstrated. This method creates false-coloured images representing the light transmission I 0 , the extinction angle φ (orientation of the optical indicatrix) and vertical stroke sin δ vertical stroke, a function of the retardation resulting from the birefringence (and a measure of the magnitude of optical anisotropy). When combined with a computer-controlled heating stage, this method provides an opportunity to create separate moving images of orientation and magnitude of optical anisotropy, showing the dynamics of twinning and domain-wall behaviour during temperature changes. It is believed that this is the first time that quantitative imaging of changes in birefringence has been used in this way to describe phase transitions. Two-phase transitions in a crystal of Na 0.5 Bi 0.5 TiO 3 (NBT) are presented as examples of the use of the system. (orig.)

  12. Microscopic observation of ferroelectric domains in SrTiO3 using birefringence imaging techniques under high electric fields

    International Nuclear Information System (INIS)

    Manaka, Hirotaka; Nozaki, Hirofumi; Miura, Yoko

    2017-01-01

    Phase transitions in SrTiO 3 between quantum paraelectric, coherent paraelectric, and electric-field-induced ferroelectric states are governed by tetragonal domains with quantum fluctuations. However, their characteristics are still unclear. To observe the electric-field-induced ferroelectric state using birefringence imaging techniques, we developed a suitable sample holder to apply high electric fields of up to E ≃ 5 kV/cm and temperatures down to T = 20 K. From birefringence imaging measurements of the ferroelectric LiNbO 3 with varying electric field, distributions of the electric field in the sample stage were found to be negligible. In SrTiO 3 , a huge-retardance area corresponding to the ferroelectric domains appears at E > 2 kV/cm and T ≤ 60 K even though the paraelectric domains partially remain. Furthermore, the fast-axis direction rotates by 90° at the ferroelectric phase transition because of an electrostrictive effect in ferroelectrics. The phase diagram of the critical electric field and temperature agrees with previous reports obtained from dielectric and neutron scattering measurements. (author)

  13. Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis

    Science.gov (United States)

    Zhang, Yibo; Lee, Seung Yoon Celine; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

    2016-06-01

    Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings.

  14. Design of a birefringent Michelson interferometer-based interleaver with ultra-low dispersion and low cost.

    Science.gov (United States)

    Hu, Haocheng; Zheng, Baozhong; Liu, Qingming; Li, Yang; Wu, Li; Gu, Shijie

    2011-11-21

    We design and demonstrate a birefringent Michelson interferometer based interleaver with ultra-low dispersion and low cost. The interleaver consists of polarizing beam splitters (PBS's) and quarter-wave plates and half-wave plates. The PBS's based Michelson interferometers provide the optical path difference for interference between the two orthogonal polarization components and the half-wave plates provide the birefringent needed to minimize ripple of output. The designed interleaver with two-stage interferometer in a 50 GHz channel spacing application exhibits a 0.5 dB passband and a 25 dB stopband both 27 GHz; a channel isolation higher than 35 dB and chromatic dispersion less than ±5 ps/nm within 0.5 dB passband; 1.3 dB insertion loss and 0.3 dB PDL; 0.04 GHz/°C thermal stability. Since all of the optical components can be optically bonded together, the device is robust and easy to be aligned, which reduces labor cost. © 2011 Optical Society of America

  15. Urban fall traps

    Directory of Open Access Journals (Sweden)

    Vera Lucia de Almeida Valsecchi

    2007-06-01

    Full Text Available Objectives: To evaluate the repercussion of falls in the elderly peoplewho live in the city of São Paulo and address - though synthetically- some questions regarding the city and its relation to aging and thequality of life of the elderly. Methods: This is a qualitative study. As fordata collection, “in-depth individual interviews” were applied. Selectionof subjects was guided by a procedure named as “network”. Results:Ten interviews were performed, nine with elderly individuals who werevictims of falls and one with a public authority representative. Dataresulting from interviews confirmed that significant changes occurin live of the elderly, who are victims of what has been called “urbantraps”, and that, by extrapolating mobility and dependence contexts,invade feelings, emotions and desires. The inappropriate environmentprovided by the city of São Paulo is confirmed by absence of adequateurban planning and lack of commitment of public authorities. It alsorevealed that the particular way of being old and living an elderlylife, in addition to right to citizenship, is reflected by major or lesserdifficulties imposed to the elderly to fight for their rights and have theirpublic space respected. Conclusion: The city of São Paulo is not anideal locus for an older person to live in. To the traps that are found inpublic places one can add those that are found in private places andthat contribute to the hard experience of falls among the elderly, anexperience that is sometimes fatal. In Brazil, the attention is basicallyfocused on the consequences of falls and not on prevention, by meansof urban planning that should meet the needs of the most vulnerablegroups - the physically disabled and the elderly.

  16. Innovation: the classic traps.

    Science.gov (United States)

    Kanter, Rosabeth Moss

    2006-11-01

    these traps.

  17. Mini ion trap mass spectrometer

    Science.gov (United States)

    Dietrich, D.D.; Keville, R.F.

    1995-09-19

    An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

  18. Charged particle traps II applications

    CERN Document Server

    Werth, Günther; Major, Fouad G

    2009-01-01

    This, the second volume of Charged Particle Traps, is devoted to applications, complementing the first volume’s comprehensive treatment of the theory and practice of charged particle traps, their many variants and refinements. In recent years, applications of far reaching importance have emerged ranging from the ultra-precise mass determinations of elementary particles and their antiparticles and short-lived isotopes, to high-resolution Zeeman spectroscopy on multiply-charged ions, to microwave and optical spectroscopy, some involving "forbidden" transitions from metastable states of such high resolution that optical frequency standards are realized by locking lasers to them. Further the potential application of trapped ions to quantum computing is explored, based on the extraordinary quantum state coherence made possible by the particle isolation. Consideration is given to the Paul and Penning traps as potential quantum information processors.

  19. Holes in magneto electrostatic traps

    International Nuclear Information System (INIS)

    Jones, R.

    1996-01-01

    We observe that in magneto electrostatic confinement (MEC) devices the magnetic surfaces are not always equipotentials. The lack of symmetry in the equipotential surfaces can result in holes in MEC plasma traps. (author)

  20. Trapping Triatominae in Silvatic Habitats

    Directory of Open Access Journals (Sweden)

    Noireau François

    2002-01-01

    Full Text Available Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial. The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.

  1. Microstructure Hierarchical Model of Competitive e+-Ps Trapping in Nanostructurized Substances: from Nanoparticle-Uniform to Nanoparticle-Biased Systems.

    Science.gov (United States)

    Shpotyuk, Oleh; Ingram, Adam; Bujňáková, Zdenka; Baláž, Peter

    2017-12-01

    Microstructure hierarchical model considering the free-volume elements at the level of interacting crystallites (non-spherical approximation) and the agglomerates of these crystallites (spherical approximation) was developed to describe free-volume evolution in mechanochemically milled As 4 S 4 /ZnS composites employing positron annihilation spectroscopy in a lifetime measuring mode. Positron lifetime spectra were reconstructed from unconstrained three-term decomposition procedure and further subjected to parameterization using x3-x2-coupling decomposition algorithm. Intrinsic inhomogeneities due to coarse-grained As 4 S 4 and fine-grained ZnS nanoparticles were adequately described in terms of substitution trapping in positron and positronium (Ps) (bound positron-electron) states due to interfacial triple junctions between contacting particles and own free-volume defects in boundary compounds. Compositionally dependent nanostructurization in As 4 S 4 /ZnS nanocomposite system was imagined as conversion from o-Ps trapping sites to positron traps. The calculated trapping parameters that were shown could be useful to characterize adequately the nanospace filling in As 4 S 4 /ZnS composites.

  2. Science, conservation, and camera traps

    Science.gov (United States)

    Nichols, James D.; Karanth, K. Ullas; O'Connel, Allan F.; O'Connell, Allan F.; Nichols, James D.; Karanth, K. Ullas

    2011-01-01

    Biologists commonly perceive camera traps as a new tool that enables them to enter the hitherto secret world of wild animals. Camera traps are being used in a wide range of studies dealing with animal ecology, behavior, and conservation. Our intention in this volume is not to simply present the various uses of camera traps, but to focus on their use in the conduct of science and conservation. In this chapter, we provide an overview of these two broad classes of endeavor and sketch the manner in which camera traps are likely to be able to contribute to them. Our main point here is that neither photographs of individual animals, nor detection history data, nor parameter estimates generated from detection histories are the ultimate objective of a camera trap study directed at either science or management. Instead, the ultimate objectives are best viewed as either gaining an understanding of how ecological systems work (science) or trying to make wise decisions that move systems from less desirable to more desirable states (conservation, management). Therefore, we briefly describe here basic approaches to science and management, emphasizing the role of field data and associated analyses in these processes. We provide examples of ways in which camera trap data can inform science and management.

  3. Status of THe-trap

    Energy Technology Data Exchange (ETDEWEB)

    Ketter, Jochen; Eronen, Tommi; Hoecker, Martin; Streubel, Sebastian; Blaum, Klaus [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Van Dyck, Robert S. Jr. [Department of Physics, University of Washington, Seattle, WA (United States)

    2012-07-01

    Originally developed at the University of Washington and relocated to the Max-Planck-Institut fuer Kernphysik in 2008, the Penning-trap spectrometer THe-Trap is specially tailored for a {sup 3}H/{sup 3}He mass-ratio measurement, from which the Q-value of the beta-decay of {sup 3}H to {sup 3}He can be derived. Improving the current best value by at least an order of magnitude will provide an important independent test parameter for the determination of the electron-antineutrino's mass by the Karlsruhe Tritium Neutrino Experiment (KATRIN). However, Penning-trap mass spectrometry has to be pushed to its limits in a dedicated experiment for a sufficiently accurate mass-ratio measurement with a relative uncertainty of 10{sup -11}. Unlike the closed-envelope, single-trap predecessor, the new spectrometer features an external ion source, owing to the radioactive nature of tritium, and two traps in order to speed up the measurement cycle. While the double-trap technique holds great promise, it also calls for more intricate procedures, such as ion transfer. Details about the recent progress of the experiment are given.

  4. Bariatric Arterial Embolization with Non-spherical Polyvinyl Alcohol Particles for Ghrelin Suppression in a Swine Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Min; Kim, Man-Deuk, E-mail: mdkim@yuhs.ac; Han, Kichang; Muqmiroh, Lailatul [Yonsei University College of Medicine, Department of Radiology, Research Institute of Radiological Science, Severance Hospital (Korea, Republic of); Kim, Seung Up [Yonsei University College of Medicine, Department of Internal Medicine, Severance Hospital (Korea, Republic of); Kim, Gyoung Min; Kwon, Joonho; Park, Sung Il; Won, Jong Yun; Lee, Do Yun [Yonsei University College of Medicine, Department of Radiology, Research Institute of Radiological Science, Severance Hospital (Korea, Republic of)

    2017-05-15

    PurposeTo evaluate the effect of bariatric arterial embolization (BAE) with non-spherical polyvinyl alcohol (PVA) particles on systemic ghrelin levels, weight change, and gastric ulceration risk in a swine model.Materials and MethodsFrom March 2014 to February 2015, ten healthy swine were used in the study (mean weight 31.5 kg; range 24.0–41.5 kg). The animals were randomly assigned to two groups: the embolized group (n = 5) in which BAE was performed and the control group (n = 5). In the embolized group, BAE was performed by selectively infusing 150–250 or 50–150 μm PVA into the gastric arteries that supplied the fundus of the stomach. In the control group, a sham procedure was performed with saline infusion. Plasma ghrelin levels were prospectively obtained at baseline and every 2 weeks thereafter. Endoscopy was performed 3 weeks after BAE to see whether any gastric ulcer occurred. To determine the durability of the occluded arteries, repeated celiac trunk angiography was performed 8 weeks after BAE. Then, all the swine were killed and necropsies were performed.ResultsThe mean post-procedure ghrelin value decreased by 370.0 pg/mL in the embolized group at week 3 (mean 536.0 ± 334.3 pg/mL) and week 5 (mean 515.0 ± 150.0 pg/mL, p < 0.05) relative to baseline (880.0 ± 559.5 pg/mL), respectively, but ghrelin levels were not significantly decreased between the embolized and control groups. There was a significant body weight change as follows: 35.1 ± 9.5 to 46.6 ± 15.7 kg and 31.8 ± 5.8 to 41.2 ± 6.6 kg at baseline and endpoint in the control and embolized groups, respectively (p < 0.05). However, the difference between groups was not significant at endpoint. In the embolized group, ulcerations were identified in three animals (60%) and the recanalization of the embolized arteries was noted on follow-up angiography in three animals (60%), respectively.ConclusionBAE with PVA particles can transiently suppress ghrelin

  5. Bariatric Arterial Embolization with Non-spherical Polyvinyl Alcohol Particles for Ghrelin Suppression in a Swine Model

    International Nuclear Information System (INIS)

    Kim, Jae Min; Kim, Man-Deuk; Han, Kichang; Muqmiroh, Lailatul; Kim, Seung Up; Kim, Gyoung Min; Kwon, Joonho; Park, Sung Il; Won, Jong Yun; Lee, Do Yun

    2017-01-01

    PurposeTo evaluate the effect of bariatric arterial embolization (BAE) with non-spherical polyvinyl alcohol (PVA) particles on systemic ghrelin levels, weight change, and gastric ulceration risk in a swine model.Materials and MethodsFrom March 2014 to February 2015, ten healthy swine were used in the study (mean weight 31.5 kg; range 24.0–41.5 kg). The animals were randomly assigned to two groups: the embolized group (n = 5) in which BAE was performed and the control group (n = 5). In the embolized group, BAE was performed by selectively infusing 150–250 or 50–150 μm PVA into the gastric arteries that supplied the fundus of the stomach. In the control group, a sham procedure was performed with saline infusion. Plasma ghrelin levels were prospectively obtained at baseline and every 2 weeks thereafter. Endoscopy was performed 3 weeks after BAE to see whether any gastric ulcer occurred. To determine the durability of the occluded arteries, repeated celiac trunk angiography was performed 8 weeks after BAE. Then, all the swine were killed and necropsies were performed.ResultsThe mean post-procedure ghrelin value decreased by 370.0 pg/mL in the embolized group at week 3 (mean 536.0 ± 334.3 pg/mL) and week 5 (mean 515.0 ± 150.0 pg/mL, p < 0.05) relative to baseline (880.0 ± 559.5 pg/mL), respectively, but ghrelin levels were not significantly decreased between the embolized and control groups. There was a significant body weight change as follows: 35.1 ± 9.5 to 46.6 ± 15.7 kg and 31.8 ± 5.8 to 41.2 ± 6.6 kg at baseline and endpoint in the control and embolized groups, respectively (p < 0.05). However, the difference between groups was not significant at endpoint. In the embolized group, ulcerations were identified in three animals (60%) and the recanalization of the embolized arteries was noted on follow-up angiography in three animals (60%), respectively.ConclusionBAE with PVA particles can transiently suppress ghrelin

  6. Effects of oxide traps, interface traps, and ''border traps'' on metal-oxide-semiconductor devices

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Winokur, P.S.; Reber, R.A. Jr.; Meisenheimer, T.L.; Schwank, J.R.; Shaneyfelt, M.R.; Riewe, L.C.

    1993-01-01

    We have identified several features of the 1/f noise and radiation response of metal-oxide-semiconductor (MOS) devices that are difficult to explain with standard defect models. To address this issue, and in response to ambiguities in the literature, we have developed a revised nomenclature for defects in MOS devices that clearly distinguishes the language used to describe the physical location of defects from that used to describe their electrical response. In this nomenclature, ''oxide traps'' are simply defects in the SiO 2 layer of the MOS structure, and ''interface traps'' are defects at the Si/SiO 2 interface. Nothing is presumed about how either type of defect communicates with the underlying Si. Electrically, ''fixed states'' are defined as trap levels that do not communicate with the Si on the time scale of the measurements, but ''switching states'' can exchange charge with the Si. Fixed states presumably are oxide traps in most types of measurements, but switching states can either be interface traps or near-interfacial oxide traps that can communicate with the Si, i.e., ''border traps'' [D. M. Fleetwood, IEEE Trans. Nucl. Sci. NS-39, 269 (1992)]. The effective density of border traps depends on the time scale and bias conditions of the measurements. We show the revised nomenclature can provide focus to discussions of the buildup and annealing of radiation-induced charge in non-radiation-hardened MOS transistors, and to changes in the 1/f noise of MOS devices through irradiation and elevated-temperature annealing

  7. Trapping, self-trapping and the polaron family

    International Nuclear Information System (INIS)

    Stoneham, A M; Gavartin, J; Shluger, A L; Kimmel, A V; Ramo, D Munoz; Roennow, H M; Aeppli, G; Renner, C

    2007-01-01

    The earliest ideas of the polaron recognized that the coupling of an electron to ionic vibrations would affect its apparent mass and could effectively immobilize the carrier (self-trapping). We discuss how these basic ideas have been generalized to recognize new materials and new phenomena. First, there is an interplay between self-trapping and trapping associated with defects or with fluctuations in an amorphous solid. In high dielectric constant oxides, like HfO 2 , this leads to oxygen vacancies having as many as five charge states. In colossal magnetoresistance manganites, this interplay makes possible the scanning tunnelling microscopy (STM) observation of polarons. Second, excitons can self-trap and, by doing so, localize energy in ways that can modify the material properties. Third, new materials introduce new features, with polaron-related ideas emerging for uranium dioxide, gate dielectric oxides, Jahn-Teller systems, semiconducting polymers and biological systems. The phonon modes that initiate self-trapping can be quite different from the longitudinal optic modes usually assumed to dominate. Fourth, there are new phenomena, like possible magnetism in simple oxides, or with the evolution of short-lived polarons, like muons or excitons. The central idea remains that of a particle whose properties are modified by polarizing or deforming its host solid, sometimes profoundly. However, some of the simpler standard assumptions can give a limited, indeed misleading, description of real systems, with qualitative inconsistencies. We discuss representative cases for which theory and experiment can be compared in detail

  8. A magnetic particle micro-trap for large trapping surfaces

    KAUST Repository

    Gooneratne, Chinthaka P.

    2012-01-08

    Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

  9. A magnetic particle micro-trap for large trapping surfaces

    KAUST Repository

    Gooneratne, Chinthaka P.; Liang, Cai; Giouroudi, Ioanna; Kosel, Jü rgen

    2012-01-01

    Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

  10. Particle trapping in stimulated scattering processes

    International Nuclear Information System (INIS)

    Karttunen, S.J.; Heikkinen, J.A.

    1981-01-01

    Particle trapping effects on stimulated Brillouin and Raman scattering are investigated. A time and space dependent model assumes a Maxwellian plasma which is taken to be homogeneous in the interaction region. Ion trapping has a rather weak effect on stimulated Brillouin scattering and large reflectivities are obtained even in strong trapping regime. Stimulated Raman scattering is considerably reduced by electron trapping. Typically 15-20 times larger laser intensities are required to obtain same reflectivity levels than without trapping. (author)

  11. Calcium Atom Trap for Atom Trap Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Kwang Hoon; Park, Hyun Min; Han, Jae Min; Kim, Taek Soo; Cha, Yong Ho; Lim, Gwon; Jeong, Do Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    Trace isotope analysis has been an important role in science, archaeological dating, geology, biology and nuclear industry. Artificially produced fission products such as Sr-90, Cs-135 and Kr-85 can be released to the environment when nuclear accident occurs and the reprocessing factory operates. Thus, the analysis of them has been of interest in nuclear industry. But it is difficult to detect them due to low natural abundance less then 10-10. The ultra-trace radio isotopes have been analyzed by the radio-chemical method, accelerator mass spectrometer, and laser based method. The radiochemical method has been used in the nuclear industry. But this method has disadvantages of long measurement time for long lived radioisotopes and toxic chemical process for the purification. The accelerator mass spectrometer has high isotope selectivity, but the system is huge and it has the isobar effects. The laser based method, such as RIMS (Resonance Ionization Mass Spectrometry) is a basically isobar-effect free method. Recently, ATTA (Atom Trap Trace Analysis), one of the laser based method, has been successfully demonstrated sufficient isotope selectivity with small system size. It has been applied for the detection of Kr-81 and Kr-85. However, it is not suitable for real sample detection, because it requires steady atomic beam generation during detection and is not allowed simultaneous detection of other isotopes. Therefore, we proposed the coupled method of Atom Trap and Mass Spectrometer. It consists of three parts, neutral atom trap, ionization and mass spectrometer. In this paper, we present the demonstration of the magneto-optical trap of neutral calcium. We discuss the isotope selective characteristics of the MOT (Magneto Optical Trap) of calcium by the fluorescence measurement. In addition, the frequency stabilization of the trap beam will be presented

  12. Scattering by nonspherical particles of size comparable to wavelength - A new semi-empirical theory and its application to tropospheric aerosols

    Science.gov (United States)

    Pollack, J. B.; Cuzzi, J. N.

    1980-01-01

    A semiempirical theory is developed which is based on simple physical principles and comparisons with laboratory measurements. The ultimate utility of this approach rests on its ability to successfully reproduce the observed single-scattering phase function for a wide variety of particle shapes, sizes and refractive indices. This approximate theory is developed for evaluating the interaction of randomly oriented, nonspherical particles with the total intensity component of electromagnetic radiation. Mie theory is used when the particle size parameter x (ratio of particle circumference to wavelength) is less than some upper bound x sub zero (about 5). For x greater than x sub zero, the interaction is divided into three components: diffraction, external reflection and transmission. The application of the theory is illustrated by considering the influence of the shape of tropospheric aerosols on their contribution to the earth's global albedo.

  13. Polarized Radiative Transfer of a Cirrus Cloud Consisting of Randomly Oriented Hexagonal Ice Crystals: The 3 x 3 Approximation for Non-Spherical Particles

    Science.gov (United States)

    Stamnes, S.; Ou, S. C.; Lin, Z.; Takano, Y.; Tsay, S. C.; Liou, K.N.; Stamnes, K.

    2016-01-01

    The reflection and transmission of polarized light for a cirrus cloud consisting of randomly oriented hexagonal columns were calculated by two very different vector radiative transfer models. The forward peak of the phase function for the ensemble-averaged ice crystals has a value of order 6 x 10(exp 3) so a truncation procedure was used to help produce numerically efficient yet accurate results. One of these models, the Vectorized Line-by-Line Equivalent model (VLBLE), is based on the doubling- adding principle, while the other is based on a vector discrete ordinates method (VDISORT). A comparison shows that the two models provide very close although not entirely identical results, which can be explained by differences in treatment of single scattering and the representation of the scattering phase matrix. The relative differences in the reflected I and Q Stokes parameters are within 0.5 for I and within 1.5 for Q for all viewing angles. In 1971 Hansen showed that for scattering by spherical particles the 3 x 3 approximation is sufficient to produce accurate results for the reflected radiance I and the degree of polarization (DOP), and he conjectured that these results would hold also for non-spherical particles. Simulations were conducted to test Hansen's conjecture for the cirrus cloud particles considered in this study. It was found that the 3 x 3 approximation also gives accurate results for the transmitted light, and for Q and U in addition to I and DOP. For these non-spherical ice particles the 3 x 3 approximation leads to an absolute error 2 x 10(exp -6) for the reflected and transmitted I, Q and U Stokes parameters. Hence, it appears to be an excellent approximation, which significantly reduces the computational complexity and burden required for multiple scattering calculations.

  14. Tunneling effects in electromagnetic wave scattering by nonspherical particles: A comparison of the Debye series and physical-geometric optics approximations

    International Nuclear Information System (INIS)

    Bi, Lei; Yang, Ping

    2016-01-01

    The accuracy of the physical-geometric optics (PG-O) approximation is examined for the simulation of electromagnetic scattering by nonspherical dielectric particles. This study seeks a better understanding of the tunneling effect on the phase matrix by employing the invariant imbedding method to rigorously compute the zeroth-order Debye series, from which the tunneling efficiency and the phase matrix corresponding to the diffraction and external reflection are obtained. The tunneling efficiency is shown to be a factor quantifying the relative importance of the tunneling effect over the Fraunhofer diffraction near the forward scattering direction. Due to the tunneling effect, different geometries with the same projected cross section might have different diffraction patterns, which are traditionally assumed to be identical according to the Babinet principle. For particles with a fixed orientation, the PG-O approximation yields the external reflection pattern with reasonable accuracy, but ordinarily fails to predict the locations of peaks and minima in the diffraction pattern. The larger the tunneling efficiency, the worse the PG-O accuracy is at scattering angles less than 90°. If the particles are assumed to be randomly oriented, the PG-O approximation yields the phase matrix close to the rigorous counterpart, primarily due to error cancellations in the orientation-average process. Furthermore, the PG-O approximation based on an electric field volume-integral equation is shown to usually be much more accurate than the Kirchhoff surface integral equation at side-scattering angles, particularly when the modulus of the complex refractive index is close to unity. Finally, tunneling efficiencies are tabulated for representative faceted particles. - Highlights: • Concepts of diffraction, reflection and tunneling are refined. • The diffraction together with reflection is rigorously treated. • An improved invariant imbedding method is employed to compute the Debye

  15. Neutral atom traps of radioactives

    International Nuclear Information System (INIS)

    Behr, J.A.

    2003-01-01

    Neutral atoms trapped with modern laser cooling techniques offer the promise of improving several broad classes of experiments with radioactive isotopes. In nuclear β decay, neutrino spectroscopy from beta-recoil coincidences, along with highly polarized samples, enable experiments to search for non-Standard Model interactions, test whether parity symmetry is maximally violated, and search for new sources of time reversal violation. Ongoing efforts at TRIUMF, Los Alamos and Berkeley will be highlighted. The traps also offer bright sources for Doppler-free spectroscopy, particularly in high-Z atoms where precision measurements could measure the strength of weak neutral nucleon-nucleon and electron-nucleon interactions. Physics with francium atoms has been vigorously pursued at Stony Brook. Several facilities plan work with radioactive atom traps; concrete plans and efforts at KVI Groningen and Legnaro will be among those summarized. Contributions to the multidisciplinary field of trace analysis will be left up to other presenters

  16. Neutral atom traps of radioactives

    CERN Document Server

    Behr, J A

    2003-01-01

    Neutral atoms trapped with modern laser cooling techniques offer the promise of improving several broad classes of experiments with radioactive isotopes. In nuclear beta decay, neutrino spectroscopy from beta-recoil coincidences, along with highly polarized samples, enable experiments to search for non-Standard Model interactions, test whether parity symmetry is maximally violated, and search for new sources of time reversal violation. Ongoing efforts at TRIUMF, Los Alamos and Berkeley will be highlighted. The traps also offer bright sources for Doppler-free spectroscopy, particularly in high-Z atoms where precision measurements could measure the strength of weak neutral nucleon-nucleon and electron-nucleon interactions. Physics with francium atoms has been vigorously pursued at Stony Brook. Several facilities plan work with radioactive atom traps; concrete plans and efforts at KVI Groningen and Legnaro will be among those summarized. Contributions to the multidisciplinary field of trace analysis will be left...

  17. Trapped atoms along nanophotonic resonators

    Science.gov (United States)

    Fields, Brian; Kim, May; Chang, Tzu-Han; Hung, Chen-Lung

    2017-04-01

    Many-body systems subject to long-range interactions have remained a very challenging topic experimentally. Ultracold atoms trapped in extreme proximity to the surface of nanophotonic structures provides a dynamic system combining the strong atom-atom interactions mediated by guided mode photons with the exquisite control implemented with trapped atom systems. The hybrid system promises pair-wise tunability of long-range interactions between atomic pseudo spins, allowing studies of quantum magnetism extending far beyond nearest neighbor interactions. In this talk, we will discuss our current status developing high quality nanophotonic ring resonators, engineered on CMOS compatible optical chips with integrated nanostructures that, in combination with a side illuminating beam, can realize stable atom traps approximately 100nm above the surface. We will report on our progress towards loading arrays of cold atoms near the surface of these structures and studying atom-atom interaction mediated by photons with high cooperativity.

  18. Linear to Circular Polarisation Conversion using Birefringent Properties of Aligned Crystals for Multi-GeV Photons

    CERN Document Server

    Apyan, A.; Badelek, B.; Ballestrero, S.; Biino, C.; Birol, I.; Cenci, P.; Connell, S.H.; Eichblatt, S.; Fonseca, T.; Freund, A.; Gorini, B.; Groess, R.; Ispirian, K.; Ketel, T.J.; Kononets, Yu.V.; Lopez, A.; Mangiarotti, A.; van Rens, B.; Sellschop, J.P.F.; Shieh, M.; Sona, P.; Strakhovenko, V.; Uggerhoj, E.; Uggerhj, Ulrik Ingerslev; Unel, G.; Velasco, M.; Vilakazi, Z.Z.; Wessely, O.; Kononets, Yu.V.

    2003-01-01

    We present the first experimental results on the use of a thick aligned Si crystal acting as a quarter wave plate to induce a degree of circular polarisation in a high energy linearly polarised photon beam. The linearly polarised photon beam is produced from coherent bremsstrahlung radiation by 178 GeV unpolarised electrons incident on an aligned Si crystal, acting as a radiator. The linear polarisation of the photon beam is characterised by measuring the asymmetry in electron-positron pair production in a Ge crystal, for different crystal orientations. The Ge crystal therefore acts as an analyser. The birefringence phenomenon, which converts the linear polarisation to circular polarisation, is observed by letting the linearly polarised photons beam pass through a thick Si quarter wave plate crystal, and then measuring the asymmetry in electron-positron pair production again for a selection of relative angles between the crystallographic planes of the radiator, analyser and quarter wave plate. The systematics...

  19. Effects of optical feedback in a birefringence-Zeeman dual frequency laser at high optical feedback levels

    International Nuclear Information System (INIS)

    Mao Wei; Zhang Shulian

    2007-01-01

    Optical feedback effects are studied in a birefringence-Zeeman dual frequency laser at high optical feedback levels. The intensity modulation features of the two orthogonally polarized lights are investigated in both isotropic optical feedback (IOF) and polarized optical feedback (POF). In IOF, the intensities of both beams are modulated simultaneously, and four zones, i.e., the e-light zone, the o-light and e-light zone, the o-light zone, and the no-light zone, are formed in a period corresponding to a half laser wavelength displacement of the feedback mirror. In POF, the two orthogonally polarized lights will oscillate alternately. Strong mode competition can be observed, and it affects the phase difference between the two beams greatly. The theoretical analysis is presented, which is in good agreement with the experimental results. The potential use of the experimental results is also discussed

  20. A study of cooperative Jahn-Teller phase transitions in rare-earth vanadates by linear birefringence

    International Nuclear Information System (INIS)

    Gehring, G.A.; Harley, R.T.; Macfarlane, R.M.

    1980-01-01

    Changes in linear birefringence (Δn) associated with the cooperative Jahn-Teller phase transition of DyV04 near 14K as as a function of temperature and magnetic fields, B, between 0.024 and 0.095T have been measured. Theoretical arguments show that Δn is directly proportional to the order parameter of the transition and that B(2) is equivalent to the conjugate ordering field. By extrapolation to zero field the temperature dependence of the order parameter and the susceptibility were obtained. The data are compared with calculations based on a mean-field 'compressible' Ising model. For a reasonable choice of adjustable parameters this classical description gives a good fit to the data close to Tsub(D) consistent with general theoretical arguments and more detailed calculations, but it deviates progressively away from Tsub(D) presumably because of the known importance of short-range interactions in the system. (author)

  1. Quantized motion of trapped ions

    International Nuclear Information System (INIS)

    Steinbach, J.

    1999-01-01

    This thesis is concerned with a theoretical and numerical study of the preparation and coherent manipulation of quantum states in the external and internal degrees of freedom of trapped ions. In its first part, this thesis proposes and investigates schemes for generating several nonclassical states for the quantized vibrational motion of a trapped ion. Based on dark state preparation specific laser excitation configurations are presented which, given appropriately chosen initial states, realize the desired motional states in the steady-state, indicated by the cessation of the fluorescence emitted by the ion. The focus is on the SU(1,1) intelligent states in both their single- and two-mode realization, corresponding to one- and two-dimensional motion of the ion. The presented schemes are also studied numerically using a Monte-Carlo state-vector method. The second part of the thesis describes how two vibrational degrees of freedom of a single trapped ion can be coupled through the action of suitably chosen laser excitation. Concentrating on a two-dimensional ion trap with dissimilar vibrational frequencies a variety of quantized two-mode couplings are derived. The focus is on a linear coupling that takes excitations from one mode to another. It is demonstrated how this can result in a state rotation, in which it is possible to coherently transfer the motional state of the ion between orthogonal directions without prior knowledge of that motional state. The third part of this thesis presents a new efficient method for generating maximally entangled internal states of a collection of trapped ions. The method is deterministic and independent of the number of ions in the trap. As the essential element of the scheme a mechanism for the realization of a controlled NOT operation that can operate on multiple ions is proposed. The potential application of the scheme for high-precision frequency standards is explored. (author)

  2. Open trap with ambipolar mirrors

    International Nuclear Information System (INIS)

    Dimov, G.I.; Zakajdakov, V.V.; Kishinevskij, M.E.

    1977-01-01

    Results of numerical calculations on the behaviour of a thermonuclear plasma, allowing for α-particles in a trap with longitudinal confinement of the main ions by ambipolar electric fields are presented. This trap is formed by connecting two small-volume ''mirrortrons'' to an ordinary open trap. Into the extreme mirrortrons, approximately 1-MeV ions are introduced continuously by ionization of atomic beams on the plasma, and approximately 10-keV ions are similarly introduced into the main central region of the trap. By a suitable choice of injection currents, the plasma density established in the extreme mirrortrons is higher than in the central region. As a result of the quasi-neutrality condition, a longitudinal ambipolar field forming a potential well not only for electrons but also for the central ions is formed in the plasma. When the depth of the well for the central ions is much greater than their temperature, their life-time considerably exceeds the time of confinement by the magnetic mirrors. As a result, the plasma density is constant over the entire length of the central mirrortron, including the regions near the mirrors, and an ambipolar field is formed only in the extreme mirrortrons. The distribution of central ions and ambipolar potential in the extreme mirrortrons is uniquely determined by the density distribution of fast extreme ions. It is shown in the present study that an amplification coefficient Q as high as desired can, in principle, be reached in the trap under consideration, allowing for α-particles. However, this requires high magnetic fields in the mirrors and a sufficient length of the central mirrotron. It is shown that for moderate values of Q=3-8, it is desirable not to confine the central fast α-particles. To achieve a coefficient of Q=5, it is necessary to create fields of 250 kG in the mirrors, and the length of the trap must not be greater than 100 m. (author)

  3. Measuring the nematic order of suspensions of colloidal fd virus by x-ray diffraction and optical birefringence

    International Nuclear Information System (INIS)

    Purdy, Kirstin R.; Dogic, Zvonimir; Fraden, Seth; Ruehm, Adrian; Lurio, Lawrence; Mochrie, Simon G. J.

    2003-01-01

    The orientational distribution function of the nematic phase of suspensions of the semiflexible rodlike virus fd is measured by x-ray diffraction as a function of concentration and ionic strength. X-ray diffraction from a single-domain nematic phase of fd is influenced by interparticle correlations at low angle, while only intraparticle scatter contributes at high angle. Consequently, the angular distribution of the scattered intensity arises from only the single-particle orientational distribution function at high angle but it also includes spatial and orientational correlations at low angle. Experimental measurements of the orientational distribution function from both the interparticle (structure factor) and intraparticle (form factor) scattering were made to test whether the correlations present in interparticle scatter influence the measurement of the single-particle orientational distribution function. It was found that the two types of scatter yield consistent values for the nematic order parameter. It was also found that x-ray diffraction is insensitive to the orientational distribution function's precise form, and the measured angular intensity distribution is described equally well by both Onsager's trial function and a Gaussian. At high ionic strength, the order parameter S of the nematic phase coexisting with the isotropic phase approaches theoretical predictions for long semiflexible rods S=0.55, but deviations from theory increase with decreasing ionic strength. The concentration dependence of the nematic order parameter also better agrees with theoretical predictions at high ionic strength indicating that electrostatic interactions have a measurable effect on the nematic order parameter. The x-ray order parameters are shown to be proportional to the measured birefringence, and the saturation birefringence of fd is determined enabling a simple, inexpensive way to measure the order parameter. Additionally, the spatial ordering of nematic fd was probed

  4. Optical levitation and long-working-distance trapping: From spherical up to high aspect ratio ellipsoidal particles

    International Nuclear Information System (INIS)

    Mihiretie, Besira; Loudet, Jean-Christophe; Pouligny, Bernard

    2013-01-01

    Radiation pressure forces from a moderately focused vertical laser beam are used to levitate transparent particles, a few micrometers in size. Having recalled basic results about levitation of spheres, and applications to long-working distance trapping, we turn to ellipsoid-shaped particles. Experiments are carried out with polystyrene particles, inside a glass chamber filled with water. The particles are lifted up to contact with the chamber top surface. We examine particle equilibrium in such conditions and show that the system “bifurcates” between static on-axis equilibrium with short ellipsoids, to sustained oscillations with longer ones. A similar Hopf bifurcation is found using a simple ray-optics model of the laser-ellipsoid interaction, providing a qualitative account of the observed oscillations. -- Highlights: ► We study optical levitation of non-spherical micrometer-sized particles. ► Short ellipsoids get trapped on laser beam axis, similarly to spheres. ► Long ellipsoids oscillate, through coupled translation and tilt motions. ► We propose a simple ray-optics model of light interaction with an ellipsoid. ► From computed radiation pressure forces, we explain the observed oscillations

  5. Ion trap architectures and new directions

    Science.gov (United States)

    Siverns, James D.; Quraishi, Qudsia

    2017-12-01

    Trapped ion technology has seen advances in performance, robustness and versatility over the last decade. With increasing numbers of trapped ion groups worldwide, a myriad of trap architectures are currently in use. Applications of trapped ions include: quantum simulation, computing and networking, time standards and fundamental studies in quantum dynamics. Design of such traps is driven by these various research aims, but some universally desirable properties have lead to the development of ion trap foundries. Additionally, the excellent control achievable with trapped ions and the ability to do photonic readout has allowed progress on quantum networking using entanglement between remotely situated ion-based nodes. Here, we present a selection of trap architectures currently in use by the community and present their most salient characteristics, identifying features particularly suited for quantum networking. We also discuss our own in-house research efforts aimed at long-distance trapped ion networking.

  6. Artificial covering on trap nests improves the colonization of trap-nesting wasps

    OpenAIRE

    Taki, Hisatomo; Kevan, Peter G.; Viana, Blandina Felipe; Silva, Fabiana O.; Buck, Matthias

    2008-01-01

    Acesso restrito: Texto completo. p. 225-229 To evaluate the role that a trap-nest cover might have on sampling methodologies, the abundance of each species of trap-nesting Hymenoptera and the parasitism rate in a Canadian forest were compared between artificially covered and uncovered traps. Of trap tubes exposed at eight forest sites in six trap-nest boxes, 531 trap tubes were occupied and 1216 individuals of 12 wasp species of four predatory families, Vespidae (Eumeninae), Crabronidae...

  7. Microfabricated linear Paul-Straubel ion trap

    Science.gov (United States)

    Mangan, Michael A [Albuquerque, NM; Blain, Matthew G [Albuquerque, NM; Tigges, Chris P [Albuquerque, NM; Linker, Kevin L [Albuquerque, NM

    2011-04-19

    An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.

  8. Asymmetric Penning trap coherent states

    International Nuclear Information System (INIS)

    Contreras-Astorga, Alonso; Fernandez, David J.

    2010-01-01

    By using a matrix technique, which allows to identify directly the ladder operators, the coherent states of the asymmetric Penning trap are derived as eigenstates of the appropriate annihilation operators. They are compared with those obtained through the displacement operator method.

  9. Indeterminacy, sunspots, and development traps

    Czech Academy of Sciences Publication Activity Database

    Slobodyan, Sergey

    2005-01-01

    Roč. 29, 1-2 (2005), s. 159-185 ISSN 0165-1889 Institutional research plan: CEZ:AV0Z70850503 Keywords : indeterminacy * development trap * stochastic stability Subject RIV: AH - Economics Impact factor: 0.691, year: 2005 http://dx.doi.org/10.1016/j.jedc.2003.04.011

  10. Efficiency of subaquatic light traps

    Czech Academy of Sciences Publication Activity Database

    Ditrich, Tomáš; Čihák, P.

    2017-01-01

    Roč. 38, č. 3 (2017), s. 171-184 ISSN 0165-0424 R&D Projects: GA ČR(CZ) GA14-29857S Institutional support: RVO:60077344 Keywords : Heteroptera * Diptera * light trap Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 0.524, year: 2016

  11. The rise of trapped populations

    Directory of Open Access Journals (Sweden)

    April T Humble

    2014-02-01

    Full Text Available As border security increases and borders become less permeable, cross-border migration is becoming increasingly difficult, selective and dangerous. Growing numbers of people are becoming trapped in their own countries or in transit countries, or being forced to roam border areas, unable to access legal protection or basic social necessities.

  12. Magnetic trapping of Rydberg atoms

    NARCIS (Netherlands)

    Niestadt, D.; Naber, J.; Kokkelmans, S.J.J.M.F.; Spreeuw, R.J.C.

    2016-01-01

    Magnetic trapping is a well-established technique for ground state atoms. We seek to extend this concept to Rydberg atoms. Rydberg atoms are important for current visions of quantum simulators that will be used in the near future to simulate and analyse quantum problems. Current efforts in Amsterdam

  13. Quantum computing with trapped ions

    International Nuclear Information System (INIS)

    Haeffner, H.; Roos, C.F.; Blatt, R.

    2008-01-01

    Quantum computers hold the promise of solving certain computational tasks much more efficiently than classical computers. We review recent experimental advances towards a quantum computer with trapped ions. In particular, various implementations of qubits, quantum gates and some key experiments are discussed. Furthermore, we review some implementations of quantum algorithms such as a deterministic teleportation of quantum information and an error correction scheme

  14. 50 CFR 697.19 - Trap limits and trap tag requirements for vessels fishing with lobster traps.

    Science.gov (United States)

    2010-10-01

    ... vessels fishing with lobster traps. 697.19 Section 697.19 Wildlife and Fisheries FISHERY CONSERVATION AND... requirements for vessels fishing with lobster traps. (a) Trap limits for vessels fishing or authorized to fish... management area designation certificate or valid limited access American lobster permit specifying one or...

  15. Scaling ion traps for quantum computing

    CSIR Research Space (South Africa)

    Uys, H

    2010-09-01

    Full Text Available The design, fabrication and preliminary testing of a chipscale, multi-zone, surface electrode ion trap is reported. The modular design and fabrication techniques used are anticipated to advance scalability of ion trap quantum computing architectures...

  16. Servo control of an optical trap.

    Science.gov (United States)

    Wulff, Kurt D; Cole, Daniel G; Clark, Robert L

    2007-08-01

    A versatile optical trap has been constructed to control the position of trapped objects and ultimately to apply specified forces using feedback control. While the design, development, and use of optical traps has been extensive and feedback control has played a critical role in pushing the state of the art, few comprehensive examinations of feedback control of optical traps have been undertaken. Furthermore, as the requirements are pushed to ever smaller distances and forces, the performance of optical traps reaches limits. It is well understood that feedback control can result in both positive and negative effects in controlled systems. We give an analysis of the trapping limits as well as introducing an optical trap with a feedback control scheme that dramatically improves an optical trap's sensitivity at low frequencies.

  17. Two-baffle trap for macroparticles

    International Nuclear Information System (INIS)

    Aksyonov, D.S.

    2014-01-01

    In this work, properties of two-baffle macroparticle traps were investigated. These properties are needed for designing and optimization of vacuum arc plasma filters. The dependencies between trap geometry parameters and its ability to absorb macroparticles were found. Calculations made allow one to predict the behaviour of filtering abilities of separators containing such traps in their design. Recommendations regarding the use of two-baffle traps in filters of different builds are given

  18. Cavity sideband cooling of trapped molecules

    NARCIS (Netherlands)

    Kowalewski, Markus; Morigi, Giovanna; Pinkse, Pepijn Willemszoon Harry; de Vivie-Riedle, Regina

    2011-01-01

    The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case in which the infrared transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped either by a radiofrequency or optical trapping

  19. An Open Standard for Camera Trap Data

    NARCIS (Netherlands)

    Forrester, Tavis; O'Brien, Tim; Fegraus, Eric; Jansen, P.A.; Palmer, Jonathan; Kays, Roland; Ahumada, Jorge; Stern, Beth; McShea, William

    2016-01-01

    Camera traps that capture photos of animals are a valuable tool for monitoring biodiversity. The use of camera traps is rapidly increasing and there is an urgent need for standardization to facilitate data management, reporting and data sharing. Here we offer the Camera Trap Metadata Standard as an

  20. Influence of trap location on the efficiency of trapping in dendrimers and regular hyperbranched polymers.

    Science.gov (United States)

    Lin, Yuan; Zhang, Zhongzhi

    2013-03-07

    The trapping process in polymer systems constitutes a fundamental mechanism for various other dynamical processes taking place in these systems. In this paper, we study the trapping problem in two representative polymer networks, Cayley trees and Vicsek fractals, which separately model dendrimers and regular hyperbranched polymers. Our goal is to explore the impact of trap location on the efficiency of trapping in these two important polymer systems, with the efficiency being measured by the average trapping time (ATT) that is the average of source-to-trap mean first-passage time over every staring point in the whole networks. For Cayley trees, we derive an exact analytic formula for the ATT to an arbitrary trap node, based on which we further obtain the explicit expression of ATT for the case that the trap is uniformly distributed. For Vicsek fractals, we provide the closed-form solution for ATT to a peripheral node farthest from the central node, as well as the numerical solutions for the case when the trap is placed on other nodes. Moreover, we derive the exact formula for the ATT corresponding to the trapping problem when the trap has a uniform distribution over all nodes. Our results show that the influence of trap location on the trapping efficiency is completely different for the two polymer networks. In Cayley trees, the leading scaling of ATT increases with the shortest distance between the trap and the central node, implying that trap's position has an essential impact on the trapping efficiency; while in Vicsek fractals, the effect of location of the trap is negligible, since the dominant behavior of ATT is identical, respective of the location where the trap is placed. We also present that for all cases of trapping problems being studied, the trapping process is more efficient in Cayley trees than in Vicsek fractals. We demonstrate that all differences related to trapping in the two polymer systems are rooted in their underlying topological structures.

  1. Fundamental physics in particle traps

    International Nuclear Information System (INIS)

    Quint, Wolfgang; Vogel, Manuel

    2014-01-01

    The individual topics are covered by leading experts in the respective fields of research. Provides readers with present theory and experiments in this field. A useful reference for researchers. This volume provides detailed insight into the field of precision spectroscopy and fundamental physics with particles confined in traps. It comprises experiments with electrons and positrons, protons and antiprotons, antimatter and highly charged ions, together with corresponding theoretical background. Such investigations represent stringent tests of quantum electrodynamics and the Standard model, antiparticle and antimatter research, test of fundamental symmetries, constants, and their possible variations with time and space. They are key to various aspects within metrology such as mass measurements and time standards, as well as promising to further developments in quantum information processing. The reader obtains a valuable source of information suited for beginners and experts with an interest in fundamental studies using particle traps.

  2. Trapping and spectroscopy of hydrogen

    International Nuclear Information System (INIS)

    Cesar, Claudio Lenz

    1997-01-01

    I review the results and techniques used by the MIT H↑ group to achieve a fractional resolution of 2 parts in 10 12 in the 1S-2S transition in hydrogen [Cesar, D. Fried, T. Killian, A. Polcyn, J. Sandberg, I.A. Yu, T. Greytak, D. Kleppner and J. Doyle, Two-photon spectroscopy of trapped atomic hydrogen, Phys. Rev. Lett. 77 (1996) 255.] With some improvements, this system should deliver 100 times higher resolution with an improved signal count rate getting us closer to an old advertised goal of a precision of 1 part in 10 18 . While these developments are very important for the proposed test of the CPT theorem through the comparison with anti-hydrogen, some of the techniques used with hydrogen are not applicable to anti-hydrogen and I discuss some difficulties and alternatives for the trapping and spectroscopy of anti-hydrogen

  3. Centrifugal trapping in the magnetotail

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    Full Text Available Particles leaving the neutral sheet in the distant magnetotail at times display adiabatic trajectory sequences characterized by an inflection toward the equator and subsequent mirroring in its vicinity. We demonstrate that this low-latitude mirroring results primarily from a centrifugal deceleration due to the fast direction-changing E×B drift. This effect which we refer to as "centrifugal trapping" appears both in guiding centre and full particle treatments. It thus does not directly relate to nonadiabatic motion. However, pitch angle scattering due to nonadiabatic neutral sheet interaction does play a role in reducing the parallel speed of the particles. We show that centrifugal trapping is an important mechanism for the confinement of the slowest (typically below the equatorial E×B drift speed plasma sheet populations to the midplane vicinity.

  4. Centrifugal trapping in the magnetotail

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    1995-03-01

    Full Text Available Particles leaving the neutral sheet in the distant magnetotail at times display adiabatic trajectory sequences characterized by an inflection toward the equator and subsequent mirroring in its vicinity. We demonstrate that this low-latitude mirroring results primarily from a centrifugal deceleration due to the fast direction-changing E×B drift. This effect which we refer to as "centrifugal trapping" appears both in guiding centre and full particle treatments. It thus does not directly relate to nonadiabatic motion. However, pitch angle scattering due to nonadiabatic neutral sheet interaction does play a role in reducing the parallel speed of the particles. We show that centrifugal trapping is an important mechanism for the confinement of the slowest (typically below the equatorial E×B drift speed plasma sheet populations to the midplane vicinity.

  5. Vapor trap for liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T

    1968-05-22

    In a pipe system which transfers liquid metal, inert gas (cover gas) is packed above the surface of the liquid metal to prevent oxidization of the liquid. If the metal vapor is contained in such cover gas, the circulating system of the cover gas is blocked due to condensation of liquid metal inside the system. The present invention relates to an improvement in vapor trap to remove the metal vapor from the cover gas. The trap consists of a cylindrical outer body, an inlet nozzle which is deeply inserted inside the outer body and has a number of holes to inject the cove gas into the body, metal mesh or steel wool which covers the exterior of the nozzle and on which the condensation of the metal gas takes place, and a heater wire hich is wound around the nozzle to prevent condensation of the metal vapor at the inner peripheral side of the mesh.

  6. Optical trapping for analytical biotechnology.

    Science.gov (United States)

    Ashok, Praveen C; Dholakia, Kishan

    2012-02-01

    We describe the exciting advances of using optical trapping in the field of analytical biotechnology. This technique has opened up opportunities to manipulate biological particles at the single cell or even at subcellular levels which has allowed an insight into the physical and chemical mechanisms of many biological processes. The ability of this technique to manipulate microparticles and measure pico-Newton forces has found several applications such as understanding the dynamics of biological macromolecules, cell-cell interactions and the micro-rheology of both cells and fluids. Furthermore we may probe and analyse the biological world when combining trapping with analytical techniques such as Raman spectroscopy and imaging. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. InP/ZnS quantum-dot-dispersed nematic liquid crystal illustrating characteristic birefringence and enhanced electro-optical parameters

    Science.gov (United States)

    Roy, Aradhana; Pathak, Govind; Herman, Jakub; Inamdar, Sanjeev R.; Srivastava, Atul; Manohar, Rajiv

    2018-03-01

    The present study investigates the influence of InP/ZnS core/shell QDs on various parameters of Nematic LC sample 1832A, based on 4-(4-alkyl-cyclohexyl)benzene isothiocyanates and 4-(4-alkyl-cyclohexyl)biphenyl isothiocyanates. Observations recorded consist of distinguished functioning of birefringence phenomenon along with characteristic response time measurement. Further study of rotational viscosity and splay elastic constant portrays stupendous behavior strengthening the appositeness of the composites for low-charge consumable devices. The addition of 0.2 ml of core/shell QDs producing more than two times faster response and enhanced birefringence at low-temperature range can be employed in development of thermostable photonic devices. In addition, dielectric properties comprising of relative permittivity and conductivity have been reported supporting the outcome of the investigation in applicative LC-based technologies.

  8. Lift enhancement by trapped vortex

    Science.gov (United States)

    Rossow, Vernon J.

    1992-01-01

    The viewgraphs and discussion of lift enhancement by trapped vortex are provided. Efforts are continuously being made to find simple ways to convert wings of aircraft from an efficient cruise configuration to one that develops the high lift needed during landing and takeoff. The high-lift configurations studied here consist of conventional airfoils with a trapped vortex over the upper surface. The vortex is trapped by one or two vertical fences that serve as barriers to the oncoming stream and as reflection planes for the vortex and the sink that form a separation bubble on top of the airfoil. Since the full three-dimensional unsteady flow problem over the wing of an aircraft is so complicated that it is hard to get an understanding of the principles that govern the vortex trapping process, the analysis is restricted here to the flow field illustrated in the first slide. It is assumed that the flow field between the two end plates approximates a streamwise strip of the flow over a wing. The flow between the endplates and about the airfoil consists of a spanwise vortex located between the suction orifices in the endplates. The spanwise fence or spoiler located near the nose of the airfoil serves to form a separated flow region and a shear layer. The vorticity in the shear layer is concentrated into the vortex by withdrawal of fluid at the suction orifices. As the strength of the vortex increases with time, it eventually dominates the flow in the separated region so that a shear or vertical layer is no longer shed from the tip of the fence. At that point, the vortex strength is fixed and its location is such that all of the velocity contributions at its center sum to zero thereby making it an equilibrium point for the vortex. The results of a theoretical analysis of such an idealized flow field are described.

  9. Antihydrogen Formation, Dynamics and Trapping

    CERN Document Server

    Butler, Eoin; Charlton, Michael

    2011-01-01

    Antihydrogen, the simplest pure-antimatter atomic system, holds the promise of direct tests of matter-antimatter equivalence and CPT invariance, two of the outstanding unanswered questions in modern physics. Antihydrogen is now routinely produced in charged-particle traps through the combination of plasmas of antiprotons and positrons, but the atoms escape and are destroyed in a minuscule fraction of a second. The focus of this work is the production of a sample of cold antihydrogen atoms in a magnetic atom trap. This poses an extreme challenge, because the state-of-the-art atom traps are only approximately 0.5 K deep for ground-state antihydrogen atoms, much shallower than the energies of particles stored in the plasmas. This thesis will outline the main parts of the ALPHA experiment, with an overview of the important physical processes at work. Antihydrogen production techniques will be described, and an analysis of the spatial annihilation distribution to give indications of the temperature and binding ene...

  10. Use of Both Cumulus Cells’ Transcriptomic Markers and Zona Pellucida Birefringence to Select Developmentally Competent Oocytes in Human Assisted Reproductive Technologies

    Science.gov (United States)

    2015-01-01

    Background Selection of the best oocyte for subsequent steps of fertilization and embryo transfer was shown to be the crucial step in human infertility treatment procedure. Oocyte selection using morphological criteria mainly Zona pellucida (ZP) has been the gold standard method in assisted reproductive technologies (ART) clinics, but this selection approach has limitations in terms of accuracy, objectivity and constancy. Recent studies using OMICs-based approaches have allowed the identification of key molecular markers that quantitatively and non-invasively predict the oocyte quality for higher pregnancy rates and efficient infertility treatment. These biomarkers are a valuable reinforcement of the morphological selection criteria widely used in in vitro fertilization (IVF) clinics. In this context, this study was designed to investigate the relationship between transcriptomic predictors of oocyte quality found by our group and the conventional morphological parameters of oocyte quality mainly the ZP birefringence. Results Microarray data revealed that 48 and 27 differentially expressed candidate genes in cumulus cells (CCs) were respectively overexpressed and underexpressed in the ZGP (Zona Good Pregnant) versus ZBNP (Zona Bad Non Pregnant) groups. More than 70% of previously reported transcriptomic biomarkers of oocyte developmental competence were confirmed in this study. The analysis of possible association between ZP birefringence versus molecular markers approach showed an absence of correlation between them using the current set of markers. Conclusions This study suggested a new integrative approach that matches morphological and molecular approaches used to select developmentally competent oocytes able to lead to successful pregnancy and the delivery of healthy baby. For each ZP birefringence score, oocytes displayed a particular CCs' gene expression pattern. However, no correlations were found between the 7 gene biomarkers of oocyte developmental

  11. Nonadiabatic transitions in electrostatically trapped ammonia molecules

    International Nuclear Information System (INIS)

    Kirste, Moritz; Schnell, Melanie; Meijer, Gerard; Sartakov, Boris G.

    2009-01-01

    Nonadiabatic transitions are known to be major loss channels for atoms in magnetic traps but have thus far not been experimentally reported upon for trapped molecules. We have observed and quantified losses due to nonadiabatic transitions for three isotopologues of ammonia in electrostatic traps by comparing the trapping times in traps with a zero and a nonzero electric field at the center. Nonadiabatic transitions are seen to dominate the overall loss rate even for the present samples that are at relatively high temperatures of 30 mK. It is anticipated that losses due to nonadiabatic transitions in electric fields are omnipresent in ongoing experiments on cold molecules.

  12. Sognenavne, Albertslund Kommune (3 artikler). trap.dk

    DEFF Research Database (Denmark)

    Kællerød, Lars-Jakob Harding

    2019-01-01

    Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Herstedvester, Herstedøster og Opstandelseskirkens Sogn......Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Herstedvester, Herstedøster og Opstandelseskirkens Sogn...

  13. Algae commensal community in Genlisea traps

    Directory of Open Access Journals (Sweden)

    Konrad Wołowski

    2011-01-01

    Full Text Available The community of algae occurring in Genlisea traps and on the external traps surface in laboratory conditions were studied. A total of 29 taxa were found inside the traps, with abundant diatoms, green algae (Chlamydophyceae and four morphotypes of chrysophytes stomatocysts. One morphotype is described as new for science. There are two ways of algae getting into Genlisea traps. The majority of those recorded inside the traps, are mobile; swimming freely by flagella or moving exuding mucilage like diatoms being ablate to colonize the traps themselves. Another possibility is transport of algae by invertebrates such as mites and crustaceans. In any case algae in the Genlisea traps come from the surrounding environment. Two dominant groups of algae (Chladymonas div. and diatoms in the trap environment, show ability to hydrolyze phosphomonoseters. We suggest that algae in carnivorous plant traps can compete with plant (host for organic phosphate (phosphomonoseters. From the spectrum and ecological requirements of algal species found in the traps, environment inside the traps seems to be acidic. However, further studies are needed to test the relations between algae and carnivorous plants both in laboratory conditions and in the natural environment. All the reported taxa are described briefly and documented with 74 LM and SEM micrographs.

  14. Ion traps fabricated in a CMOS foundry

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, K. K.; Ram, R. J. [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Eltony, A. M.; Chuang, I. L. [Center for Ultracold Atoms, Research Laboratory of Electronics and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bruzewicz, C. D.; Sage, J. M., E-mail: jsage@ll.mit.edu; Chiaverini, J., E-mail: john.chiaverini@ll.mit.edu [Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02420 (United States)

    2014-07-28

    We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This demonstration of scalable quantum computing hardware utilizing a commercial CMOS process opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

  15. Trapping Dust to Form Planets

    Science.gov (United States)

    Kohler, Susanna

    2017-10-01

    Growing a planet from a dust grain is hard work! A new study explores how vortices in protoplanetary disks can assist this process.When Dust Growth FailsTop: ALMA image of the protoplanetary disk of V1247 Orionis, with different emission components labeled. Bottom: Synthetic image constructed from the best-fit model. [Kraus et al. 2017]Gradual accretion onto a seed particle seems like a reasonable way to grow a planet from a grain of dust; after all, planetary embryos orbit within dusty protoplanetary disks, which provides them with plenty of fuel to accrete so they can grow. Theres a challenge to this picture, though: the radial drift problem.The radial drift problem acknowledges that, as growing dust grains orbit within the disk, the drag force on them continues to grow as well. For large enough dust grains perhaps around 1 millimeter the drag force will cause the grains orbits to decay, and the particles drift into the star before they are able to grow into planetesimals and planets.A Close-Up Look with ALMASo how do we overcome the radial drift problem in order to form planets? A commonly proposed mechanism is dust trapping, in which long-lived vortices in the disk trap the dust particles, preventing them from falling inwards. This allows the particles to persist for millions of years long enough to grow beyond the radial drift barrier.Observationally, these dust-trapping vortices should have signatures: we would expect to see, at millimeter wavelengths, specific bright, asymmetric structures where the trapping occurs in protoplanetary disks. Such disk structures have been difficult to spot with past instrumentation, but the Atacama Large Millimeter/submillimeter Array (ALMA) has made some new observations of the disk V1247 Orionis that might be just what were looking for.Schematic of the authors model for the disk of V1247 Orionis. [Kraus et al. 2017]Trapped in a Vortex?ALMAs observations of V1247 Orionis are reported by a team of scientists led by Stefan

  16. Trapped

    OpenAIRE

    Storvik, Pamela

    2012-01-01

    This study explores how the Muslim Sunni Women in the city of Tripoli- Lebanon perceive the the inequity in the rights of women in terms of those of men within the Personal Status codes practiced today in the Sunni Muslim Sharīʻa Courts in the country. Lebanese women and men in general are subject to an imbalanced patronage as a result of the patriarchal conditions dominating the Lebanese society and its various communities. This project further explores the factors that have led to the failu...

  17. Quantitative analysis with advanced compensated polarized light microscopy on wavelength dependence of linear birefringence of single crystals causing arthritis

    Science.gov (United States)

    Takanabe, Akifumi; Tanaka, Masahito; Taniguchi, Atsuo; Yamanaka, Hisashi; Asahi, Toru

    2014-07-01

    To improve our ability to identify single crystals causing arthritis, we have developed a practical measurement system of polarized light microscopy called advanced compensated polarized light microscopy (A-CPLM). The A-CPLM system is constructed by employing a conventional phase retardation plate, an optical fibre and a charge-coupled device spectrometer in a polarized light microscope. We applied the A-CPLM system to measure linear birefringence (LB) in the visible region, which is an optical anisotropic property, for tiny single crystals causing arthritis, i.e. monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate (CPPD). The A-CPLM system performance was evaluated by comparing the obtained experimental data using the A-CPLM system with (i) literature data for a standard sample, MgF2, and (ii) experimental data obtained using an established optical method, high-accuracy universal polarimeter, for the MSUM. The A-CPLM system was found to be applicable for measuring the LB spectra of the single crystals of MSUM and CPPD, which cause arthritis, in the visible regions. We quantitatively reveal the large difference in LB between MSUM and CPPD crystals. These results demonstrate the usefulness of the A-CPLM system for distinguishing the crystals causing arthritis.

  18. Azo polymers with electronical push and pull structures prepared via RAFT polymerization and its photoinduced birefringence behavior

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Two methacrylate monomers containing azo and electronical push and pull structure, e.g. 2-Methyl-acrylic-acid-2-{[4-(4-cyano-phenylazo-3-methyl-phenyl]-ethyl-amino-ethyl ester (MACP with cyano substituted and 2-Methylacrylic-acid-2-{ethyl-[4-(4-methoxy-phenylazo-3-methyl-phenyl]-amino}-ethyl ester (MAMP with methoxy substituted, were synthesized and polymerized using 2-cyanoprop-2-yl dithiobenzoate (CPDB as chain transfer agent and 2,2'-azobisisobutyronitrile (AIBN as initiator. The results showed that the polymerization displayed characteristics of ‘living’/controlled free radical polymerization. Thus, the obtained polymers, polyMACP (pMACP and polyMAMP (pMAMP, had controlled molecular weights and narrow molecular weights distribution. The chain extension experiments of pMACP and pMAMP using styrene as the second monomer were successfully carried out. The photo-induced trans-cis-trans isomerization kinetic of pMACP and pMAMP in chloroform solution were described. Marked differences in rate for the trans-cis and cis-trans isomerization of pMACP and pMAMP were observed in chloroform solution due to the different electronic effects in these two polymers. Photoinduced birefringence and surface relief grating (SRG of the pMACP and pMAMP were investigated in thin film state.

  19. Effects of intermode nonlinearity and intramode nonlinearity on modulation instability in randomly birefringent two-mode optical fibers

    Science.gov (United States)

    Li, Jin Hua; Xu, Hui; Sun, Ting Ting; Pei, Shi Xin; Ren, Hai Dong

    2018-05-01

    We analyze in detail the effects of the intermode nonlinearity (IEMN) and intramode nonlinearity (IRMN) on modulation instability (MI) in randomly birefringent two-mode optical fibers (RB-TMFs). In the anomalous dispersion regime, the MI gain enhances significantly as the IEMN and IRMN coefficients increases. In the normal dispersion regime, MI can be generated without the differential mode group delay (DMGD) effect, as long as the IEMN coefficient between two distinct modes is above a critical value, or the IRMN coefficient inside a mode is below a critical value. This critical IEMN (IRMN) coefficient depends strongly on the given IRMN (IEMN) coefficient and DMGD for a given nonlinear RB-TMF structure, and is independent on the input total power, the power ratio distribution and the group velocity dispersion (GVD) ratio between the two modes. On the other hand, in contrast to the MI band arising from the pure effect of DMGD in the normal dispersion regime, where MI vanishes after a critical total power, the generated MI band under the combined effects of IEMN and IRMN without DMGD exists for any total power and enhances with the total power. The MI analysis is verified numerically by launching perturbed continuous waves (CWs) with wave propagation method.

  20. Algorithms to retrieve optical properties of three component aerosols from two-wavelength backscatter and one-wavelength polarization lidar measurements considering nonsphericity of dust

    International Nuclear Information System (INIS)

    Nishizawa, Tomoaki; Sugimoto, Nobuo; Matsui, Ichiro; Shimizu, Atsushi; Okamoto, Hajime

    2011-01-01

    We developed backward and forward types of algorithms for estimating the vertical profiles of extinction coefficients at 532 nm for three component aerosols (water-soluble, dust, and sea salt) using three-channel Mie-scattering lidar data of the backscatter (β) at 532 and 1064 nm and the depolarization ratio (δ) at 532 nm. While the water-soluble and sea-salt particles were reasonably assumed to be spherical, the dust particles were treated as randomly oriented spheroids to account for their nonsphericity. The introduction of spheroid models enabled us to more effectively use the three-channel data (i.e., 2β+1δ data) and to reduce the uncertainties caused by the assumption of spherical dust particles in our previously developed algorithms. We also performed an extensive sensitivity study to estimate retrieval errors, which showed that the errors in the extinction coefficient for each aerosol component were smaller than 30% (60%) for the backward (forward) algorithm when the measurement errors were ±5%. We demonstrated the ability of the algorithms to partition aerosol layers consisting of three aerosol components by applying them to shipborne lidar data. Comparisons with sky radiometer measurements revealed that the retrieved optical thickness and angstrom exponent of aerosols using the algorithms developed in this paper agreed well with the sky radiometer measurements (within 6%).

  1. Interfacial effect on physical properties of composite media: Interfacial volume fraction with non-spherical hard-core-soft-shell-structured particles.

    Science.gov (United States)

    Xu, Wenxiang; Duan, Qinglin; Ma, Huaifa; Chen, Wen; Chen, Huisu

    2015-11-02

    Interfaces are known to be crucial in a variety of fields and the interfacial volume fraction dramatically affects physical properties of composite media. However, it is an open problem with great significance how to determine the interfacial property in composite media with inclusions of complex geometry. By the stereological theory and the nearest-surface distribution functions, we first propose a theoretical framework to symmetrically present the interfacial volume fraction. In order to verify the interesting generalization, we simulate three-phase composite media by employing hard-core-soft-shell structures composed of hard mono-/polydisperse non-spherical particles, soft interfaces, and matrix. We numerically derive the interfacial volume fraction by a Monte Carlo integration scheme. With the theoretical and numerical results, we find that the interfacial volume fraction is strongly dependent on the so-called geometric size factor and sphericity characterizing the geometric shape in spite of anisotropic particle types. As a significant interfacial property, the present theoretical contribution can be further drawn into predicting the effective transport properties of composite materials.

  2. Status and outlook of CHIP-TRAP: The Central Michigan University high precision Penning trap

    Science.gov (United States)

    Redshaw, M.; Bryce, R. A.; Hawks, P.; Gamage, N. D.; Hunt, C.; Kandegedara, R. M. E. B.; Ratnayake, I. S.; Sharp, L.

    2016-06-01

    At Central Michigan University we are developing a high-precision Penning trap mass spectrometer (CHIP-TRAP) that will focus on measurements with long-lived radioactive isotopes. CHIP-TRAP will consist of a pair of hyperbolic precision-measurement Penning traps, and a cylindrical capture/filter trap in a 12 T magnetic field. Ions will be produced by external ion sources, including a laser ablation source, and transported to the capture trap at low energies enabling ions of a given m / q ratio to be selected via their time-of-flight. In the capture trap, contaminant ions will be removed with a mass-selective rf dipole excitation and the ion of interest will be transported to the measurement traps. A phase-sensitive image charge detection technique will be used for simultaneous cyclotron frequency measurements on single ions in the two precision traps, resulting in a reduction in statistical uncertainty due to magnetic field fluctuations.

  3. Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

    CERN Document Server

    Amole, C; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Kurchaninov, L; Jonsell, S; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S

    2012-01-01

    Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antipr...

  4. Portable Pbars, traps that travel

    International Nuclear Information System (INIS)

    Howe, S.D.; Hynes, M.V.; Picklesimer, A.

    1987-10-01

    The advent of antiproton research utilizing relatively small scale storage devices for very large numbers of these particles opens the possibility of transporting these devices to a research site removed from the accelerator center that produced the antiprotons. Such a portable source of antiprotons could open many new areas of research and make antiprotons available to a new research community. At present antiprotons are available at energies down to 1 MeV. From a portable source these particles can be made available at energies ranging from several tens of kilovolts down to a few millielectron volts. These low energies are in the domain of interest to the atomic and condensed matter physicist. In addition such a source can be used as an injector for an accelerator which could increase the energy domain even further. Moreover, the availability of such a source at a university will open research with antiprotons to a broader range of students than possible at a centralized research facility. This report focuses on the use of ion traps, in particular cylindrical traps, for the antiproton storage device. These devices store the charged antiprotons in a combination of electric and magnet fields. At high enough density and low enough temperature the charged cloud will be susceptible to plasma instabilities. Present day ion trap work is just starting to explore this domain. Our assessment of feasibility is based on what could be done with present day technology and what future technology could achieve. We conclude our report with a radiation safety study that shows that about 10 11 antiprotons can be transported safely, however the federal guidelines for this transport must be reviewed in detail. More antiprotons than this will require special transportation arrangements. 28 refs., 8 figs

  5. Trapping molecules in two and three dimensions

    International Nuclear Information System (INIS)

    Pinkse, PW.H.; Junglen, T.; Rieger, T.; Rangwala, S.A.; Windpassinger, P.; Rempe, G.

    2005-01-01

    Full text: Cold molecules offer a new testing ground for quantum-physical effects in nature. For example, producing slow beams of large molecules could push experiments studying the boundary between quantum interference and classical particles up towards ever heavier particles. Moreover, cold molecules, in particular YbF, seem an attractive way to narrow down the constraints on the value of the electron dipole moment and finally, quantum information processing using chains of cold polar molecules or vibrational states in molecules have been proposed. All these proposals rely on advanced production and trapping techniques, most of which are still under development. Therefore, novel production and trapping techniques for cold molecules could offer new possibilities not found in previous methods. Electric traps hold promise for deep trap potentials for neutral molecules. Recently we have demonstrated two-dimensional trapping of polar molecules in a four-wire guide using electrostatic and electrodynamic trapping techniques. Filled from a thermal effusive source, such a guide will deliver a beam of slow molecules, which is an ideal source for interferometry experiments with large molecules, for instance. Here we report about the extension of this work to three-dimensional trapping. Polar molecules with a positive Stark shift can be trapped in the minimum of an electrostatic field. We have successfully tested a large volume electrostatic trap for ND3 molecules. A special feature of this trap is that it can be loaded continuously from an electrostatic guide, at a temperature of a few hundred mK. (author)

  6. Introduced species as evolutionary traps

    Science.gov (United States)

    Schlaepfer, Martin A.; Sherman, P.W.; Blossey, B.; Runge, M.C.

    2005-01-01

    Invasive species can alter environments in such a way that normal behavioural decision-making rules of native species are no longer adaptive. The evolutionary trap concept provides a useful framework for predicting and managing the impact of harmful invasive species. We discuss how native species can respond to changes in their selective regime via evolution or learning. We also propose novel management strategies to promote the long-term co-existence of native and introduced species in cases where the eradication of the latter is either economically or biologically unrealistic.

  7. Gyrotactic trapping: A numerical study

    Science.gov (United States)

    Ghorai, S.

    2016-04-01

    Gyrotactic trapping is a mechanism proposed by Durham et al. ["Disruption of vertical motility by shear triggers formation of thin Phytoplankton layers," Science 323, 1067-1070 (2009)] to explain the formation of thin phytoplankton layer just below the ocean surface. This mechanism is examined numerically using a rational model based on the generalized Taylor dispersion theory. The crucial role of sedimentation speed in the thin layer formation is demonstrated. The effects of variation in different parameters on the thin layer formation are also investigated.

  8. Telomerase Repeated Amplification Protocol (TRAP).

    Science.gov (United States)

    Mender, Ilgen; Shay, Jerry W

    2015-11-20

    Telomeres are found at the end of eukaryotic linear chromosomes, and proteins that bind to telomeres protect DNA from being recognized as double-strand breaks thus preventing end-to-end fusions (Griffith et al. , 1999). However, due to the end replication problem and other factors such as oxidative damage, the limited life span of cultured cells (Hayflick limit) results in progressive shortening of these protective structures (Hayflick and Moorhead, 1961; Olovnikov, 1973). The ribonucleoprotein enzyme complex telomerase-consisting of a protein catalytic component hTERT and a functional RNA component hTR or hTERC - counteracts telomere shortening by adding telomeric repeats to the end of chromosomes in ~90% of primary human tumors and in some transiently proliferating stem-like cells (Shay and Wright, 1996; Shay and Wright, 2001). This results in continuous proliferation of cells which is a hallmark of cancer. Therefore, telomere biology has a central role in aging, cancer progression/metastasis as well as targeted cancer therapies. There are commonly used methods in telomere biology such as Telomere Restriction Fragment (TRF) (Mender and Shay, 2015b), Telomere Repeat Amplification Protocol (TRAP) and Telomere dysfunction Induced Foci (TIF) analysis (Mender and Shay, 2015a). In this detailed protocol we describe Telomere Repeat Amplification Protocol (TRAP). The TRAP assay is a popular method to determine telomerase activity in mammalian cells and tissue samples (Kim et al. , 1994). The TRAP assay includes three steps: extension, amplification, and detection of telomerase products. In the extension step, telomeric repeats are added to the telomerase substrate (which is actually a non telomeric oligonucleotide, TS) by telomerase. In the amplification step, the extension products are amplified by the polymerase chain reaction (PCR) using specific primers (TS upstream primer and ACX downstream primer) and in the detection step, the presence or absence of telomerase is

  9. Bose condensation in (random traps

    Directory of Open Access Journals (Sweden)

    V.A. Zagrebnov

    2009-01-01

    Full Text Available We study a non-interacting (perfect Bose-gas in random external potentials (traps. It is shown that a generalized Bose-Einstein condensation in the random eigenstates manifests if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose-gas. Moreover, we prove that the amounts of both condensate densities are equal. This statement is relevant for justification of the Bogoliubov approximation} in the theory of disordered boson systems.

  10. Progress at THe-trap

    Energy Technology Data Exchange (ETDEWEB)

    Hoecker, Martin; Eronen, Tommi; Ketter, Jochen; Schuh, Marc; Streubel, Sebastian; Blaum, Klaus [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Van Dyck, Robert S. Jr. [Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States)

    2014-07-01

    THe-Trap is a Penning-trap mass spectrometry experiment that is currently being set up to measure the atomic mass ratio of tritium and helium-3 with a relative uncertainty of 10{sup -11}. In 2013, the experiment's first high-precision mass ratio measurement was performed on the ions {sup 12}C{sup 4+} and {sup 16}O{sup 5+}. The carbon-12/oxygen-16 mass ratio is one of the most precisely determined mass ratios and serves as a benchmark for the experiment. This measurement reached a statistical uncertainty of 6.3 . 10{sup -11} and was limited by systematic frequency shifts due to too high motional amplitudes. In the following service cycle, the experiment was modified to address the shortcomings that were discovered in the 2013 ratio measurements. This talk summarizes the results of the 2013 measurements and introduces the upgrades to the experiment, including a new amplifier, a modified ion source, and an improved vacuum system.

  11. Dynamic array of dark optical traps

    DEFF Research Database (Denmark)

    Daria, V.R.; Rodrigo, P.J.; Glückstad, J.

    2004-01-01

    A dynamic array of dark optical traps is generated for simultaneous trapping and arbitrary manipulation of multiple low-index microstructures. The dynamic intensity patterns forming the dark optical trap arrays are generated using a nearly loss-less phase-to-intensity conversion of a phase......-encoded coherent light source. Two-dimensional input phase distributions corresponding to the trapping patterns are encoded using a computer-programmable spatial light modulator, enabling each trap to be shaped and moved arbitrarily within the plane of observation. We demonstrate the generation of multiple dark...... optical traps for simultaneous manipulation of hollow "air-filled" glass microspheres suspended in an aqueous medium. (C) 2004 American Institute of Physics....

  12. Case Study: Trap Crop with Pheromone Traps for Suppressing Euschistus servus (Heteroptera: Pentatomidae in Cotton

    Directory of Open Access Journals (Sweden)

    P. G. Tillman

    2012-01-01

    Full Text Available The brown stink bug, Euschistus servus (Say, can disperse from source habitats, including corn, Zea mays L., and peanut, Arachis hypogaea L., into cotton, Gossypium hirsutum L. Therefore, a 2-year on-farm experiment was conducted to determine the effectiveness of a sorghum (Sorghum bicolor (L. Moench spp. bicolor trap crop, with or without Euschistus spp. pheromone traps, to suppress dispersal of this pest to cotton. In 2004, density of E. servus was lower in cotton fields with sorghum trap crops (with or without pheromone traps compared to control cotton fields. Similarly, in 2006, density of E. servus was lower in cotton fields with sorghum trap crops and pheromone traps compared to control cotton fields. Thus, the combination of the sorghum trap crop and pheromone traps effectively suppressed dispersal of E. servus into cotton. Inclusion of pheromone traps with trap crops potentially offers additional benefits, including: (1 reducing the density of E. servus adults in a trap crop, especially females, to possibly decrease the local population over time and reduce the overwintering population, (2 reducing dispersal of E. servus adults from the trap crop into cotton, and (3 potentially attracting more dispersing E. servus adults into a trap crop during a period of time when preferred food is not prevalent in the landscape.

  13. Diffusion to finite-size traps

    International Nuclear Information System (INIS)

    Richards, P.M.

    1986-01-01

    The survival probability of a random-walking particle is derived for hopping in a random distribution of traps of arbitrary radius and concentration. The single-center approximation is shown to be valid for times of physical interest even when the fraction of volume occupied by traps approaches unity. The theory is based on computation of the number of different potential trap regions sampled in a random walk and is confirmed by simulations on a simple-cubic lattice

  14. Laser induced fluorescence of trapped molecular ions

    International Nuclear Information System (INIS)

    Grieman, F.J.

    1979-10-01

    An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references

  15. Active stabilization of ion trap radiofrequency potentials

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, K. G.; Wong-Campos, J. D.; Restelli, A.; Landsman, K. A.; Neyenhuis, B.; Mizrahi, J.; Monroe, C. [Joint Quantum Institute and University of Maryland Department of Physics, College Park, Maryland 20742 (United States)

    2016-05-15

    We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a radiofrequency (rf) Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1 MHz atomic oscillation frequency to be better than 10 Hz or 10 ppm. This represents a suppression of ambient noise on the rf circuit by 34 dB. This technique could impact the sensitivity of ion trap mass spectrometry and the fidelity of quantum operations in ion trap quantum information applications.

  16. How to detect trap cluster systems?

    International Nuclear Information System (INIS)

    Mandowski, Arkadiusz

    2008-01-01

    Spatially correlated traps and recombination centres (trap-recombination centre pairs and larger clusters) are responsible for many anomalous phenomena that are difficult to explain in the framework of both classical models, i.e. model of localized transitions (LT) and the simple trap model (STM), even with a number of discrete energy levels. However, these 'anomalous' effects may provide a good platform for identifying trap cluster systems. This paper considers selected cluster-type effects, mainly relating to an anomalous dependence of TL on absorbed dose in the system of isolated clusters (ICs). Some consequences for interacting cluster (IAC) systems, involving both localized and delocalized transitions occurring simultaneously, are also discussed

  17. Laser induced fluorescence of trapped molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Grieman, F.J.

    1979-10-01

    An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references.

  18. Optical Trapping of Ion Coulomb Crystals

    Science.gov (United States)

    Schmidt, Julian; Lambrecht, Alexander; Weckesser, Pascal; Debatin, Markus; Karpa, Leon; Schaetz, Tobias

    2018-04-01

    The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

  19. High Optical Access Trap 2.0.

    Energy Technology Data Exchange (ETDEWEB)

    Maunz, Peter Lukas Wilhelm [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-26

    The High Optical Access (HOA) trap was designed in collaboration with the Modular Universal Scalable Ion-trap Quantum Computer (MUSIQC) team, funded along with Sandia National Laboratories through IARPA's Multi Qubit Coherent Operations (MQCO) program. The design of version 1 of the HOA trap was completed in September 2012 and initial devices were completed and packaged in February 2013. The second version of the High Optical Access Trap (HOA-2) was completed in September 2014 and is available at IARPA's disposal.

  20. Laser cooling and trapping of atoms

    International Nuclear Information System (INIS)

    Chu, S.

    1995-01-01

    The basic ideas of laser cooling and atom trapping will be discussed. These techniques have applications in spectroscopy, metrology, nuclear physics, biophysics, geophysics, and polymer science. (author)

  1. Laser-cooling and electromagnetic trapping of neutral atoms

    International Nuclear Information System (INIS)

    Phillips, W.D.; Migdall, A.L.; Metcalf, H.J.

    1986-01-01

    Until recently it has been impossible to confine and trap neutral atoms using electromagnetic fields. While many proposals for such traps exist, the small potential energy depth of the traps and the high kinetic energy of available atoms prevented trapping. We review various schemes for atom trapping, the advances in laser cooling of atomic beams which have now made trapping possible, and the successful magnetic trapping of cold sodium atoms

  2. Atypical birefringence pattern and the diagnostic ability of scanning laser polarimetry with enhanced corneal compensation in glaucoma.

    Science.gov (United States)

    Rao, Harsha L; Yadav, Ravi K; Begum, Viquar U; Addepalli, Uday K; Senthil, Sirisha; Choudhari, Nikhil S; Garudadri, Chandra S

    2015-03-01

    To evaluate the effect of typical scan score (TSS), when within the acceptable limits, on the diagnostic performance of retinal nerve fibre layer (RNFL) parameters with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in glaucoma. In a cross-sectional study, 203 eyes of 160 glaucoma patients and 140 eyes of 104 control subjects underwent RNFL imaging with the ECC protocol of SLP. TSS was used to quantify atypical birefringence pattern (ABP) images. Influence of TSS on the diagnostic ability of SLP parameters was evaluated by receiver operating characteristic (ROC) regression models after adjusting for the effect of disease severity [based on mean deviation (MD)] on standard automated perimetry). Diagnostic abilities of all RNFL parameters of SLP increased when the TSS values were higher. This effect was statistically significant for TSNIT (coefficient: 0.08, p<0.001) and inferior average parameters (coefficient: 0.06, p=0.002) but not for nerve fibre indicator (NFI, coefficient: 0.03, p=0.21). In early glaucoma (MD of -5 dB), predicted area under ROC curve (AUC) for TSNIT average parameter improved from 0.642 at a TSS of 90 to 0.845 at a TSS of 100. In advanced glaucoma (MD of -15 dB), AUC for TSNIT average improved from 0.832 at a TSS of 90 to 0.947 at 100. Diagnostic performances of TSNIT and inferior average RNFL parameters with ECC protocol of SLP were significantly influenced by TSS even when the TSS values were within the acceptable limits. Diagnostic ability of NFI was unaffected by TSS values. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  3. Computational study of scattering of a zero-order Bessel beam by large nonspherical homogeneous particles with the multilevel fast multipole algorithm

    Science.gov (United States)

    Yang, Minglin; Wu, Yueqian; Sheng, Xinqing; Ren, Kuan Fang

    2017-12-01

    Computation of scattering of shaped beams by large nonspherical particles is a challenge in both optics and electromagnetics domains since it concerns many research fields. In this paper, we report our new progress in the numerical computation of the scattering diagrams. Our algorithm permits to calculate the scattering of a particle of size as large as 110 wavelengths or 700 in size parameter. The particle can be transparent or absorbing of arbitrary shape, smooth or with a sharp surface, such as the Chebyshev particles or ice crystals. To illustrate the capacity of the algorithm, a zero order Bessel beam is taken as the incident beam, and the scattering of ellipsoidal particles and Chebyshev particles are taken as examples. Some special phenomena have been revealed and examined. The scattering problem is formulated with the combined tangential formulation and solved iteratively with the aid of the multilevel fast multipole algorithm, which is well parallelized with the message passing interface on the distributed memory computer platform using the hybrid partitioning strategy. The numerical predictions are compared with the results of the rigorous method for a spherical particle to validate the accuracy of the approach. The scattering diagrams of large ellipsoidal particles with various parameters are examined. The effect of aspect ratios, as well as half-cone angle of the incident zero-order Bessel beam and the off-axis distance on scattered intensity, is studied. Scattering by asymmetry Chebyshev particle with size parameter larger than 700 is also given to show the capability of the method for computing scattering by arbitrary shaped particles.

  4. Tunneling effects in electromagnetic wave scattering by nonspherical particles: A comparison of the Debye series and physical-geometric optics approximations

    Science.gov (United States)

    Bi, Lei; Yang, Ping

    2016-07-01

    The accuracy of the physical-geometric optics (PG-O) approximation is examined for the simulation of electromagnetic scattering by nonspherical dielectric particles. This study seeks a better understanding of the tunneling effect on the phase matrix by employing the invariant imbedding method to rigorously compute the zeroth-order Debye series, from which the tunneling efficiency and the phase matrix corresponding to the diffraction and external reflection are obtained. The tunneling efficiency is shown to be a factor quantifying the relative importance of the tunneling effect over the Fraunhofer diffraction near the forward scattering direction. Due to the tunneling effect, different geometries with the same projected cross section might have different diffraction patterns, which are traditionally assumed to be identical according to the Babinet principle. For particles with a fixed orientation, the PG-O approximation yields the external reflection pattern with reasonable accuracy, but ordinarily fails to predict the locations of peaks and minima in the diffraction pattern. The larger the tunneling efficiency, the worse the PG-O accuracy is at scattering angles less than 90°. If the particles are assumed to be randomly oriented, the PG-O approximation yields the phase matrix close to the rigorous counterpart, primarily due to error cancellations in the orientation-average process. Furthermore, the PG-O approximation based on an electric field volume-integral equation is shown to usually be much more accurate than the Kirchhoff surface integral equation at side-scattering angles, particularly when the modulus of the complex refractive index is close to unity. Finally, tunneling efficiencies are tabulated for representative faceted particles.

  5. Secretion Trap Tagging of Secreted and Membrane-Spanning Proteins Using Arabidopsis Gene Traps

    Science.gov (United States)

    Andrew T. Groover; Joseph R. Fontana; Juana M. Arroyo; Cristina Yordan; W. Richard McCombie; Robert A. Martienssen

    2003-01-01

    Secreted and membrane-spanning proteins play fundamental roles in plant development but pose challenges for genetic identification and characterization. We describe a "secretion trap" screen for gene trap insertions in genes encoding proteins routed through the secretory pathway. The gene trap transposon encodes a ß-glucuronidase reporter enzyme...

  6. Inelastic collision rates of trapped metastable hydrogen

    NARCIS (Netherlands)

    Landhuis, D; Matos, L; Moss, SC; Steinberger, JK; Vant, K; Willmann, L; Greytak, TJ; Kleppner, D

    We report the first detailed decay studies of trapped metastable (2S) hydrogen. By two-photon excitation of ultracold H samples, we have produced clouds of at least 5x10(7) magnetically trapped 2S atoms at densities greater than 4x10(10) cm(-3) and temperatures below 100 muK. At these densities and

  7. Insects in IBL-4 pine weevil traps

    Science.gov (United States)

    I. Skrzecz

    2003-01-01

    Pipe traps (IBL-4) are used in Polish coniferous plantations to monitor and control the pine weevil (Hylobius abietis L.). This study was conducted in a one-year old pine plantation established on a reforested clear-cut area in order to evaluate the impact of these traps on non-target insects. Evaluation of the catches indicated that species of

  8. Modes of oscillation in radiofrequency Paul traps

    DEFF Research Database (Denmark)

    Landa, H.; Reznik, B.; Drewsen, M.

    2012-01-01

    We examine the time-dependent dynamics of ion crystals in radiofrequency traps. The problem of stable trapping of general threedimensional crystals is considered and the validity of the pseudopotential approximation is discussed. We analytically derive the micromotion amplitude of the ions...

  9. Spin polarized atom traps and fundamental symmetries

    International Nuclear Information System (INIS)

    Haeusser, O.

    1994-10-01

    Plans are described to couple a neutral atom trap to an upgraded version of TRIUMF's TISOL on-line mass separator. The unique properties of trapped and cooled atoms promise improvements of some symmetry tests of the Standard Model of the electroweak and strong interactions. (author). 33 refs., 3 figs

  10. Astroturf seed traps for studying hydrochory

    NARCIS (Netherlands)

    Wolters, M; Geertsema, J; Chang, ER; Veeneklaas, RM; Carey, PD; Bakker, JP

    1. Astroturf mats can effectively trap diaspores dispersed by tidal water. 2. Within four tidal inundations, up to 745 propagules per m(2) and between three and eight different species per astroturf mat were trapped. Overall, 15 different species were collected on the astroturf mats, 10 of which

  11. An Experimental Analysis of Social Traps

    Science.gov (United States)

    Brechner, Kevin C.

    1977-01-01

    Social traps, such as the overgrazing of pasturelands, overpopulation, and the extinction of species, are situations where individuals in a group respond for their own advantage in a manner damaging to the group. Alaboratory analog was devised to simulate conditions that produce social traps. The intent was to cause an immediate positive…

  12. Effect of trapping on transport coherence

    International Nuclear Information System (INIS)

    Barvik, I.; Herman, P.

    1990-10-01

    Influence of a trap (sink) on an exciton transfer in molecular aggregates is investigated. Memory functions entering the generalized master equations are calculated. The presence of the sink changes their analytical form. We used the sink in trimer as example to show that for large trapping rate parameters the rest of the system is decoupled from the sink. (author). 8 refs, 2 figs

  13. Compression of Antiproton Clouds for Antihydrogen Trapping

    CERN Document Server

    Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; Van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile and its relation to that of the electron plasma.

  14. Collective excitations of harmonically trapped ideal gases

    NARCIS (Netherlands)

    Van Schaeybroeck, B.; Lazarides, A.

    2009-01-01

    We theoretically study the collective excitations of an ideal gas confined in an isotropic harmonic trap. We give an exact solution to the Boltzmann-Vlasov equation; as expected for a single-component system, the associated mode frequencies are integer multiples of the trapping frequency. We show

  15. Lobster trap detection at the Saba Bank

    NARCIS (Netherlands)

    Beek, van I.J.M.

    2012-01-01

    According to previous studies and anecdotal evidence there are a lot of lost lobster traps at the Saba Bank. One study estimated the loss to be between 210 and 795 lobster traps per year. The Saba Bank is an approximately 2,200 km2 submerged area and spiny lobster (Panulirus argus) is one of the

  16. Cryptography, quantum computation and trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard J.

    1998-03-01

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  17. Review of statistical analysis of trapped gas

    International Nuclear Information System (INIS)

    Schmittroth, F.A.

    1996-01-01

    A review was conducted of trapped gas estimates in Hanford waste tanks. Tank waste levels were found to correlate with barometric pressure changes giving the possibility to infer amounts of trapped gas. Previous models of the tank waste level were extended to include other phenomena such as evaporation in a more complete description of tank level changes

  18. Influence of trap construction on mosquito capture

    Czech Academy of Sciences Publication Activity Database

    Šebesta, Oldřich; Peško, Juraj; Gelbič, Ivan

    2012-01-01

    Roč. 6, č. 2 (2012), s. 209-215 ISSN 1934-7391 R&D Projects: GA MŠk 2B08003 Institutional research plan: CEZ:AV0Z50070508 Institutional support: RVO:68081766 ; RVO:60077344 Keywords : CDC miniature light traps * baited lard-can traps * mosquitoes Subject RIV: EG - Zoology

  19. Effect of trap position on the efficiency of trapping in treelike scale-free networks

    International Nuclear Information System (INIS)

    Zhang Zhongzhi; Lin Yuan; Ma Youjun

    2011-01-01

    The conventional wisdom is that the role and impact of nodes on dynamical processes in scale-free networks are not homogenous, because of the presence of highly connected nodes at the tail of their power-law degree distribution. In this paper, we explore the influence of different nodes as traps on the trapping efficiency of the trapping problem taking place on scale-free networks. To this end, we study in detail the trapping problem in two families of deterministically growing scale-free networks with treelike structure: one family is non-fractal, the other is fractal. In the first part of this work, we attack a special case of random walks on the two network families with a perfect trap located at a hub, i.e. node with the highest degree. The second study addresses the case with trap distributed uniformly over all nodes in the networks. For these two cases, we compute analytically the mean trapping time (MTT), a quantitative indicator characterizing the trapping efficiency of the trapping process. We show that in the non-fractal scale-free networks the MTT for both cases follows different scalings with the network order (number of network nodes), implying that trap's position has a significant effect on the trapping efficiency. In contrast, it is presented that for both cases in the fractal scale-free networks, the two leading scalings exhibit the same dependence on the network order, suggesting that the location of trap has no essential impact on the trapping efficiency. We also show that for both cases of the trapping problem, the trapping efficiency is more efficient in the non-fractal scale-free networks than in their fractal counterparts.

  20. Scattering of a cross-polarized linear wave by a soliton at an optical event horizon in a birefringent nanophotonic waveguide.

    Science.gov (United States)

    Ciret, Charles; Gorza, Simon-Pierre

    2016-06-15

    The scattering of a linear wave on an optical event horizon, induced by a cross-polarized soliton, is experimentally and numerically investigated in integrated structures. The experiments are performed in a dispersion-engineered birefringent silicon nanophotonic waveguide. In stark contrast with copolarized waves, the large difference between the group velocity of the two cross-polarized waves enables a frequency conversion almost independent of the soliton wavelength. It is shown that the generated idler is only shifted by 10 nm around 1550 nm over a pump tuning range of 350 nm. Simulations using two coupled full vectorial nonlinear Schrödinger equations fully support the experimental results.

  1. Modified semiclassical approximation for trapped Bose gases

    International Nuclear Information System (INIS)

    Yukalov, V.I.

    2005-01-01

    A generalization of the semiclassical approximation is suggested allowing for an essential extension of its region of applicability. In particular, it becomes possible to describe Bose-Einstein condensation of a trapped gas in low-dimensional traps and in traps of low confining dimensions, for which the standard semiclassical approximation is not applicable. The result of the modified approach is shown to coincide with purely quantum-mechanical calculations for harmonic traps, including the one-dimensional harmonic trap. The advantage of the semiclassical approximation is in its simplicity and generality. Power-law potentials of arbitrary powers are considered. The effective thermodynamic limit is defined for any confining dimension. The behavior of the specific heat, isothermal compressibility, and density fluctuations is analyzed, with an emphasis on low confining dimensions, where the usual semiclassical method fails. The peculiarities of the thermodynamic characteristics in the effective thermodynamic limit are discussed

  2. Magnetic trapping of cold bromine atoms.

    Science.gov (United States)

    Rennick, C J; Lam, J; Doherty, W G; Softley, T P

    2014-01-17

    Magnetic trapping of bromine atoms at temperatures in the millikelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br2 molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are lost only by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.

  3. Cold trap disposed within a tank

    International Nuclear Information System (INIS)

    Kanbe, Mitsuru.

    1983-01-01

    Purpose: To improve the reliability and the durability of cold traps by simplifying the structure and recycling liquid metals without using electromagnetic pumps. Constitution: The reactor container is partitioned by an intermediate container enhousing primary recycling pumps and cold traps. The inlet and the exit for the liquid metal of each cold trap are opened to the outside and the inside of the intermediate container respectively. In such a structure, the pressure difference between the inside and the outside of the intermediate container is exerted on the cold traps due to the exhaust pressure of the recycling pumps in which the liquid metal flowing into the cold traps is purified through filters, cooled and then discharged from the exit to the cold plenum. In this way, liquid metal can be recycled without using an electromagnetic pump whose reliability has not yet been established. (Kamimura, M.)

  4. The Aarhus Ion Micro-Trap Project

    DEFF Research Database (Denmark)

    Miroshnychenko, Yevhen; Nielsen, Otto; Poulsen, Gregers

    As part of our involvement in the EU MICROTRAP project, we have designed, manufactured and assembled a micro-scale ion trap with integrated optical fibers. These prealigned fibers will allow delivering cooling laser light to single ions. Therefore, such a trap will not require any direct optical...... and installed in an ultra high vacuum chamber, which includes an ablation oven for all-optical loading of the trap [2]. The next steps on the project are to demonstrate the operation of the micro-trap and the cooling of ions using fiber delivered light. [1] D. Grant, Development of Micro-Scale Ion traps, Master...... Thesis (2008). [2] R.J. Hendricks, D.M. Grant, P.F. Herskind, A. Dantan and M. Drewsen, An all-optical ion-loading technique for scalable microtrap architectures, Applied Physics B, 88, 507 (2007)....

  5. The hidden traps in decision making.

    Science.gov (United States)

    Hammond, J S; Keeney, R L; Raiffa, H

    1998-01-01

    Bad decisions can often be traced back to the way the decisions were made--the alternatives were not clearly defined, the right information was not collected, the costs and benefits were not accurately weighted. But sometimes the fault lies not in the decision-making process but rather in the mind of the decision maker. The way the human brain works can sabotage the choices we make. John Hammond, Ralph Keeney, and Howard Raiffa examine eight psychological traps that are particularly likely to affect the way we make business decisions: The anchoring trap leads us to give disproportionate weight to the first information we receive. The statusquo trap biases us toward maintaining the current situation--even when better alternatives exist. The sunk-cost trap inclines us to perpetuate the mistakes of the past. The confirming-evidence trap leads us to seek out information supporting an existing predilection and to discount opposing information. The framing trap occurs when we misstate a problem, undermining the entire decision-making process. The overconfidence trap makes us overestimate the accuracy of our forecasts. The prudence trap leads us to be overcautious when we make estimates about uncertain events. And the recallability trap leads us to give undue weight to recent, dramatic events. The best way to avoid all the traps is awareness--forewarned is forearmed. But executives can also take other simple steps to protect themselves and their organizations from the various kinds of mental lapses. The authors show how to take action to ensure that important business decisions are sound and reliable.

  6. Nonlinear spectroscopy of trapped ions

    Science.gov (United States)

    Schlawin, Frank; Gessner, Manuel; Mukamel, Shaul; Buchleitner, Andreas

    2014-08-01

    Nonlinear spectroscopy employs a series of laser pulses to interrogate dynamics in large interacting many-body systems, and it has become a highly successful method for experiments in chemical physics. Current quantum optical experiments approach system sizes and levels of complexity that require the development of efficient techniques to assess spectral and dynamical features with scalable experimental overhead. However, established methods from optical spectroscopy of macroscopic ensembles cannot be applied straightforwardly to few-atom systems. Based on the ideas proposed in M. Gessner et al., (arXiv:1312.3365), we develop a diagrammatic approach to construct nonlinear measurement protocols for controlled quantum systems, and we discuss experimental implementations with trapped ion technology in detail. These methods, in combination with distinct features of ultracold-matter systems, allow us to monitor and analyze excitation dynamics in both the electronic and vibrational degrees of freedom. They are independent of system size, and they can therefore reliably probe systems in which, e.g., quantum state tomography becomes prohibitively expensive. We propose signals that can probe steady-state currents, detect the influence of anharmonicities on phonon transport, and identify signatures of chaotic dynamics near a quantum phase transition in an Ising-type spin chain.

  7. Laser trapping of radioactive francium atoms

    International Nuclear Information System (INIS)

    Sprouse, G.D.; Orozco, L.A.; Simsarian, J.E.; Shi, W.; Zhao, W.Z.

    1997-01-01

    The difficult problem of quickly slowing and cooling nuclear reaction products so that they can be injected into a laser trap has been solved by several groups and there are now strong efforts to work with the trapped atoms. The atoms are confined in the trap to a small spatial volume of the order of 1 mm 3 , but more importantly, they are also confined in velocity, which makes them an ideal sample for spectroscopic measurements with other lasers. We have recently trapped radioactive francium and have embarked on a program to further study the francium atom as a prelude to a test of the Standard Model analogous to previous work with Cs. Our sample of 3 min 210 Fr now contains over 20 000 atoms, and is readily visible with an ordinary TV camera. We work on-line with the accelerator, and continuously load the trap to replace losses due to decay and collisions with background gas. We have maintained a sample of Fr atoms in the trap for over 10 hours, with occasional adjustment of the trapping laser frequency to account for drifts. The proposed test of the Standard Model will require accurate calculation of its atomic properties. We are currently testing these calculations by measuring other predicted quantities. (orig.)

  8. An Open Standard for Camera Trap Data

    Directory of Open Access Journals (Sweden)

    Tavis Forrester

    2016-12-01

    Full Text Available Camera traps that capture photos of animals are a valuable tool for monitoring biodiversity. The use of camera traps is rapidly increasing and there is an urgent need for standardization to facilitate data management, reporting and data sharing. Here we offer the Camera Trap Metadata Standard as an open data standard for storing and sharing camera trap data, developed by experts from a variety of organizations. The standard captures information necessary to share data between projects and offers a foundation for collecting the more detailed data needed for advanced analysis. The data standard captures information about study design, the type of camera used, and the location and species names for all detections in a standardized way. This information is critical for accurately assessing results from individual camera trapping projects and for combining data from multiple studies for meta-analysis. This data standard is an important step in aligning camera trapping surveys with best practices in data-intensive science. Ecology is moving rapidly into the realm of big data, and central data repositories are becoming a critical tool and are emerging for camera trap data. This data standard will help researchers standardize data terms, align past data to new repositories, and provide a framework for utilizing data across repositories and research projects to advance animal ecology and conservation.

  9. Single-molecule dynamics in nanofabricated traps

    Science.gov (United States)

    Cohen, Adam

    2009-03-01

    The Anti-Brownian Electrokinetic trap (ABEL trap) provides a means to immobilize a single fluorescent molecule in solution, without surface attachment chemistry. The ABEL trap works by tracking the Brownian motion of a single molecule, and applying feedback electric fields to induce an electrokinetic motion that approximately cancels the Brownian motion. We present a new design for the ABEL trap that allows smaller molecules to be trapped and more information to be extracted from the dynamics of a single molecule than was previously possible. In particular, we present strategies for extracting dynamically fluctuating mobilities and diffusion coefficients, as a means to probe dynamic changes in molecular charge and shape. If one trapped molecule is good, many trapped molecules are better. An array of single molecules in solution, each immobilized without surface attachment chemistry, provides an ideal test-bed for single-molecule analyses of intramolecular dynamics and intermolecular interactions. We present a technology for creating such an array, using a fused silica plate with nanofabricated dimples and a removable cover for sealing single molecules within the dimples. With this device one can watch the shape fluctuations of single molecules of DNA or study cooperative interactions in weakly associating protein complexes.

  10. Residual CO2 trapping in Indiana limestone.

    Science.gov (United States)

    El-Maghraby, Rehab M; Blunt, Martin J

    2013-01-02

    We performed core flooding experiments on Indiana limestone using the porous plate method to measure the amount of trapped CO(2) at a temperature of 50 °C and two pressures: 4.2 and 9 MPa. Brine was mixed with CO(2) for equilibration, then the mixture was circulated through a sacrificial core. Porosity and permeability tests conducted before and after 884 h of continuous core flooding confirmed negligible dissolution. A trapping curve for supercritical (sc)CO(2) in Indiana showing the relationship between the initial and residual CO(2) saturations was measured and compared with that of gaseous CO(2). The results were also compared with scCO(2) trapping in Berea sandstone at the same conditions. A scCO(2) residual trapping end point of 23.7% was observed, indicating slightly less trapping of scCO(2) in Indiana carbonates than in Berea sandstone. There is less trapping for gaseous CO(2) (end point of 18.8%). The system appears to be more water-wet under scCO(2) conditions, which is different from the trend observed in Berea; we hypothesize that this is due to the greater concentration of Ca(2+) in brine at higher pressure. Our work indicates that capillary trapping could contribute to the immobilization of CO(2) in carbonate aquifers.

  11. Optical Trapping of Ion Coulomb Crystals

    Directory of Open Access Journals (Sweden)

    Julian Schmidt

    2018-05-01

    Full Text Available The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

  12. Laser trapping of 21Na atoms

    International Nuclear Information System (INIS)

    Lu, Zheng-Tian.

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive 21 Na (t l/2 = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped 21 Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of 21 Na → 21 Ne + Β + + v e , which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, 21 Na atoms were produced by bombarding 24 Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The 21 Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined

  13. Real-time measurement system for tracking birefringence, weight, thickness, and surface temperature during drying of solution cast coatings and films

    Science.gov (United States)

    Unsal, E.; Drum, J.; Yucel, O.; Nugay, I. I.; Yalcin, B.; Cakmak, M.

    2012-02-01

    This paper describes the design and performance of a new instrument to track temporal changes in physical parameters during the drying behavior of solutions, as well as curing of monomers. This real-time instrument follows in-plane and out-of-plane birefringence, weight, thickness, and surface temperature during the course of solidification of coatings and films through solvent evaporation and thermal or photocuring in a controlled atmosphere. It is specifically designed to simulate behavior of polymer solutions inside an industrial size, continuous roll-to-roll solution casting line and other coating operations where resins are subjected to ultraviolet (UV) curing from monomer precursors. Controlled processing parameters include air speed, temperature, initial cast thickness, and solute concentration, while measured parameters are thickness, weight, film temperature, in-plane and out-of-plane birefringence. In this paper, we illustrate the utility of this instrument with solution cast and dried poly (amide-imide)/DMAc (Dimethylacetamide) solution, water based black paint, and organo-modified clay/NMP (N-Methylpyrrolidone) solution. In addition, the physical changes that take place during UV photo polymerization of a monomer are tracked. This instrument is designed to be generic and it can be used for tracking any drying/swelling/solidification systems including paper, foodstuffs such as; grains, milk as well as pharmaceutical thin paste and slurries.

  14. Form birefringence analysis in a grating by means of modal theory; Analisis de la birrefringencia de forma en una rejilla mediante la teoria modal

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Ponce, G.; Solano, Cristina [Centro de Investigaciones en Optica A.C, Guanajuato (Mexico)

    2001-02-01

    The propagation of a plane electromagnetic wave through a grating using the modal theory is analyzed. The eigenproblem is solved in function of the ratio illumination wavelength {lambda} to grating period (d). When this ratio is much greater than one (quasiestatic limit), the grating shows a response similar to an uniaxial film. It is possible to approximate the eigenfunction for calculating the effective refractive indices of the birefringent element. This effect is called form birefringence and can be used to design retardation plates. [Spanish] En este trabajo se analiza la propagacion de una onda electromagnetica plana a traves de una rejilla utilizando la teoria modal. Estableciendo el problema de valor caracteristico se determina que la solucion es dependiente de la razon longitud de onda de iluminacion {lambda} y el periodo de la rejilla (d). En el caso {lambda}/d mayor que 1, conocido como el limite cuasiestatico, la rejilla se comporta como una pelicula uniaxial, obteniendose los indices ordinario y extraordinario a partir de una aproximacion a la ecuacion caracteristica. Este fenomeno, llamado birrefringencia de forma, puede emplearse para disenar elementos birrefringentes.

  15. Biases in Drosophila melanogaster protein trap screens

    Directory of Open Access Journals (Sweden)

    Müller Ilka

    2009-05-01

    Full Text Available Abstract Background The ability to localise or follow endogenous proteins in real time in vivo is of tremendous utility for cell biology or systems biology studies. Protein trap screens utilise the random genomic insertion of a transposon-borne artificial reporter exon (e.g. encoding the green fluorescent protein, GFP into an intron of an endogenous gene to generate a fluorescent fusion protein. Despite recent efforts aimed at achieving comprehensive coverage of the genes encoded in the Drosophila genome, the repertoire of genes that yield protein traps is still small. Results We analysed the collection of available protein trap lines in Drosophila melanogaster and identified potential biases that are likely to restrict genome coverage in protein trap screens. The protein trap screens investigated here primarily used P-element vectors and thus exhibit some of the same positional biases associated with this transposon that are evident from the comprehensive Drosophila Gene Disruption Project. We further found that protein trap target genes usually exhibit broad and persistent expression during embryonic development, which is likely to facilitate better detection. In addition, we investigated the likely influence of the GFP exon on host protein structure and found that protein trap insertions have a significant bias for exon-exon boundaries that encode disordered protein regions. 38.8% of GFP insertions land in disordered protein regions compared with only 23.4% in the case of non-trapping P-element insertions landing in coding sequence introns (p -4. Interestingly, even in cases where protein domains are predicted, protein trap insertions frequently occur in regions encoding surface exposed areas that are likely to be functionally neutral. Considering the various biases observed, we predict that less than one third of intron-containing genes are likely to be amenable to trapping by the existing methods. Conclusion Our analyses suggest that the

  16. An atom trap relying on optical pumping

    International Nuclear Information System (INIS)

    Bouyer, P.; Lemonde, P.; Ben Dahan, M.; Michaud, A.; Salomon, C.; Dalibard, J.

    1994-01-01

    We have investigated a new radiation pressure trap which relies on optical pumping and does not require any magnetic field. It employs six circularly polarized divergent beams and works on the red of a J g →J e = J g + 1 atomic transition with J g ≥1/2. We have demonstrated this trap with cesium atoms from a vapour cell using the 852 nm J g = 4→J e = 5 resonance transition. The trap contained up to 3.10 7 atoms in a cloud of 1/√e radius of 330 μm. (orig.)

  17. Medfly female attractant trapping studies in Guatemala

    International Nuclear Information System (INIS)

    Jeronimo, F.; Rendon, P.; Villatoro, C.

    1999-01-01

    Experiments were conducted from 1994 - 1998 to test the attractiveness of combinations of food-based chemicals for C. capitata (medfly) in Guatemala. Most studies were done in coffee. The 1995 studies, using the FA-2 attractants (ammonium acetate and putrescine) showed that this combination was attractive for females and had potential for use in conjunction with a SIT program. The 1996 studies at three elevations demonstrated that, in general, these attractants, when used in either the Open Bottom Dry Trap (OBDT), Closed Bottom Dry Trap (CBDT), or International Pheromone's McPhail Trap (IPMT) performed better than the Jumbo McPhail trap (JMT) baited with NuLure and borax (NU+B) for capture of feral females. At the high elevation (1400 m), the IPMT with FA-2 and OBDT with FA-2 were best; at the middle elevation (1100 m), the ORDT, IPMT, and CBDT with FA-2 were best; and at low elevations (659 m), the IPMT with FA-2, JMT with NU+B and ORDT with FA-2 were equal in performance. At the middle elevation, using sterile flies, the OBDT with FA-2 worked best. When experiments were carried out in pear, the traps using the FA-2 attractants captured more female flies than the JMT, NU+B, but not significantly more. During the 1997 trials, a third component, trimethylamine was added to the two component lure (FA-3). This attractant was tested in a number of locally produced traps using 2 I soft drink bottles with different color bottoms. The dry versions of the traps contained a yellow sticky insert. All study sites were at low elevation 600 - 650 m, in coffee, testing both sterile and feral flies. With the feral flies during the first phase of the study at finca San Carlos, there were no significant differences between treatments, at finca San Luis, the clear local trap with sticky insert and the green local trap with sticky insert were best, and at finca Valapraiso, the green local trap with yellow sticky insert and yellow local trap with sticky insert captured more flies

  18. Separation of effects of oxide-trapped charge and interface-trapped charge on mobility in irradiated power MOSFETs

    International Nuclear Information System (INIS)

    Zupac, D.; Galloway, K.F.; Khosropour, P.; Anderson, S.R.; Schrimpf, R.D.

    1993-01-01

    An effective approach to separating the effects of oxide-trapped charge and interface-trapped charge on mobility degradation in irradiated MOSFETs is demonstrated. It is based on analyzing mobility data sets which have different functional relationships between the radiation-induced-oxide-trapped charge and interface-trapped charge. Separation of effects of oxide-trapped charge and interface-trapped charge is possible only if these two trapped charge components are not linearly dependent. A significant contribution of oxide-trapped charge to mobility degradation is demonstrated and quantified

  19. Radionuclide trap for liquid metal cooled reactors

    International Nuclear Information System (INIS)

    McGuire, J.C.; Brehm, W.F.

    1978-10-01

    At liquid metal cooled reactor operating temperatures, radioactive corrosion product transport and deposition in the primary system will be sufficiently high to limit access time for maintenance of system components. A radionuclide trap has been developed to aid in controlling radioactivity transport. This is a device which is located above the reactor core and which acts as a getter, physically immobilizing radioactive corrosion products, particularly 54 Mn. Nickel is the getter material used. It is most effective at temperatures above 450 0 C and effectiveness increases with increasing temperature. Prototype traps have been tested in sodium loops for 40,000 hours at reactor primary temperatures and sodium velocities. Several possible in-reactor trap sites were considered but a location within the top of each driver assembly was chosen as the most convenient and effective. In this position the trap is changed each time fuel is changed

  20. Comments on 'Generation of Deccan Trap magmas'

    Indian Academy of Sciences (India)

    R.Narasimhan(krishtel emaging)1461 1996 Oct 15 13:05:22

    Comments on 'Generation of Deccan Trap magmas' by Gautam Sen ... Department of Geology & Geophysics, School of Ocean & Earth Science & Technology (SOEST), University of .... Mahoney J J, Sheth H C, Chandrasekharan D and Peng Z.

  1. AEgIS antihydrogen production trap

    CERN Multimedia

    Caraban Gonzalez, Noemi

    2017-01-01

    During technical stop 2017 the AEgIS experiment was open for upgrades and maintenance. We had the opportunity to take some 360 images from inside and see where antiprotons are ¨trapped¨ and anti-Hydrogen produced.

  2. Vapour trap development and operational experience

    International Nuclear Information System (INIS)

    Jansing, W.; Kirchner, G.; Menck, J.

    1977-01-01

    Sodium aerosols have the unpleasant characteristic that they deposit at places with low temperature level. This effect can be utilized when sodium aerosols are to be trapped at places which are determined beforehand. Thus vapour traps were developed which can filter sodium vapour from the cover gas. By this means the necessity was eliminated to heat all gas lines and gas systems with trace heaters just as all sodium lines are heated. It was of special interest for the INTERATOM to develop vapour traps which must not be changed or cleaned after a certain limited operating period. The vapour traps were supposed to enable maintenance free operation, i.e. they were to operate 'self cleaning'

  3. ATRAP on the way to trapped Antihydrogen

    CERN Document Server

    Grzonka, D; Gabrielse, G; Goldenbaum, F; Hänsch, T W; Hessels, E A; Larochelle, P; Le Sage, D; Levitt, B; Oelert, W; Pittner, H; Sefzick, T; Speck, A; Storry, C H; Walz, J; Zhang, Z

    2005-01-01

    The ATRAP experiment at the CERN antiproton decelerator AD aims for a test of the CPT invariance by a high precision comparison of the 1s‐2s transition in the hydrogen and the antihydrogen atom. Antihydrogen production is routinely operated at ATRAP and detailed studies have been performed in order to optimize the production efficiency of useful antihydrogen. The shape parameters of the antiproton and positron clouds, the n‐state distribution of the produced Rydberg antihydrogen atoms and the antihydrogen velocity have been studied. Furthermore an alternative method of laser controlled antihydrogen production was successfully applied. For high precision measurements of atomic transitions cold antihydrogen in the ground state is required which must be trapped due to the low number of available antihydrogen atoms compared to the cold hydrogen beam used for hydrogen spectroscopy. To ensure a reasonable antihydrogen trapping efficiency a magnetic trap has to be superposed the nested Penning trap. First trappi...

  4. Defect trapping of deuterium implanted in aluminium

    International Nuclear Information System (INIS)

    Kido, Y.; Kakeno, M.; Yamada, K.; Hioki, T.; Kawamoto, J.

    1982-01-01

    The behaviour of deuterium implanted in Al was studied by the D( 3 He,p) 4 He and the D(d,p)T nuclear reactions. Changes of the depth profiles of the deuterium after heat treatments indicated that the implanted deuterium was trapped by the defect produced during the deuterium implantation and the release probability of the trapped deuterium increased as the specimen temperature was raised. Assuming a thermal equilibrium locally in the region of high defect concentration, the trapping energy of deuterium in Al was determined to be 0.12eV. Since the release probability for the single crystal was considerably larger than that for the polycrystal specimens, the deuterium was considered to be strongly trapped in the grain boundaries. Distributions of displaced Al atoms and the recovery of the lattice damage by annealing were measured by the channelling technique. (author)

  5. Curious behavior of optically trapped neutral atoms

    International Nuclear Information System (INIS)

    Wieman, C.; Walker, T.; Sesko, D.; Monroe, C.

    1991-01-01

    We have studied the behavior of clouds of neutral atoms contained in a spontaneous force optical trap. Because of the low temperatures of the atoms ( 5 atoms. These include the expansion of the cloud as the number is increased and dramatic changes in the distribution of the atoms at higher numbers. We can explain much of the collective behavior using a simple model that includes a 1/r 2 force between the atoms arising from the multiple scattering of photons. Finally, we discuss the optical trapping of atoms directly from a low pressure vapor in a small glass cell. We have used these optically trapped atoms to load a magnetostatic trap in the same cell. This provided a high density sample of atoms with a temperature of less than 2 μK

  6. Whistler wave trapping in a density crest

    International Nuclear Information System (INIS)

    Sugai, H.; Niki, H.; Inutake, M.; Takeda, S.

    1979-11-01

    The linear trapping process of whistler waves in a field-aligned density crest is investigated theoretically and experimentally below ω = ωsub(c)/2 (half gyrofrequency). The conditions of the crest trapping are derived in terms of the frequency ω/ωsub(c), the incident wave-normal angle theta sub(i), and the density ratio n sub(i)/n sub(o), where n sub(i) and n sub(o) denote the density at the incident point and that at the ridge, respectively. The oscillation length of the trapped ray path is calculated for a parabolic density profile. The experiment on antenna-excited whistler wave has been performed in a large magnetized plasma with the density crest. The phase and amplitude profile of the whistler wave is measured along and across the crest. The measurement has verified characteristic behaviors of the crest trapping. (author)

  7. Methods in mooring deep sea sediment traps

    Digital Repository Service at National Institute of Oceanography (India)

    Venkatesan, R.; Fernando, V.; Rajaraman, V.S.; Janakiraman, G.

    The experience gained during the process of deployment and retrieval of nearly 39 sets of deep sea sediment trap moorings on various ships like FS Sonne, ORV Sagarkanya and DSV Nand Rachit are outlined. The various problems encountered...

  8. Sodium hydride precipitation in sodium cold traps

    International Nuclear Information System (INIS)

    McPheeters, C.C.; Raue, D.J.

    1980-06-01

    A series of experiments have been performed to test a calculational model for precipitation of NaH in sodium cold traps. The calculational model, called ACTMODEL, is a computer simulation that uses the system geometry and operating conditions as input to calculate a mass-transfer coefficient and the distribution of NaH in a cold trap. The ACTMODEL was tested using an analytical cold trap (ACT) that is simple and essentially one-dimensional. The ACT flow and temperature profile can be controlled at any desired condition. The ACT was analyzed destructively after each test to measure the actual NaH distribution. Excellent agreement was obtained between the ACTMODEL simulations and the experiments. Mass-transfer coefficients ranging upward from 6 x 10 -5 m/s were measured in both packless and packed traps. As much as a fourfold increase in precipitation surface area was observed with increasing amount of NaH deposited. 11 figures, 2 tables

  9. Traps in Zirconium Alloys Oxide Layers

    Directory of Open Access Journals (Sweden)

    Helmar Frank

    2005-01-01

    Full Text Available Oxide films long-time grown on tubes of three types of zirconium alloys in water and in steam were investigated, by analysing I-V characteristic measured at constant voltages with various temperatures. Using theoretical concepts of Rose [3] and Gould [5], ZryNbSn(Fe proved to have an exponential distribution of trapping centers below the conduction band edge, wheras Zr1Nb and IMP Zry-4 proved to have single energy trap levels.

  10. Coherent states approach to Penning trap

    International Nuclear Information System (INIS)

    Fernandez, David J; Velazquez, Mercedes

    2009-01-01

    By using a matrix technique, which allows us to identify directly the ladder operators, the Penning trap coherent states are derived as eigenstates of the appropriate annihilation operators. These states are compared with those obtained through the displacement operator. The associated wavefunctions and mean values for some relevant operators in these states are also evaluated. It turns out that the Penning trap coherent states minimize the Heisenberg uncertainty relation

  11. The ALPHA Experiment a Cold Antihydrogen Trap

    CERN Document Server

    Bertsche, W; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Chartier, M; Deutsch, A; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D; Gomberoff, K; Grote, D P; Hangst, J S; Hayano, R S; Jenkins, M; Jørgensen, L V; Madsen, N; Miranda, D; Nolan, P; Ochanski, K; Olin, A; Page, R D; Posada, L G C; Robicheaux, F; Sarid, E; Telle, H H; Vay, J L; Wurtele, J; van der Werf, D P; Yamazaki, Y

    2005-01-01

    The ALPHA experiment aims to trap antihydrogen as the next crucial step towards a precise CPT test, by a spectroscopic comparison of antihydrogen with hydrogen. The experiment will retain the salient techniques developed by the ATHENA collaboration during the previous phase of antihydrogen experiments at the antiproton decelerator (AD) at CERN. The collaboration has identified the key problems in adding a neutral antiatom trap to the previously developed experimental configuration. The solutions identified by ALPHA are described in this paper.

  12. Deuterium transport and trapping in polycrystalline tungsten

    International Nuclear Information System (INIS)

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R.; Pawelko, R.J.; Trybus, C.L.; Sellers, C.H.

    1992-01-01

    This paper reports that deuterium permeation studies for polycrystalline tungsten foil have been conducted to provide data for estimating tritium transport and trapping in tungsten-clad divertors proposed for advanced fusion-reactor concepts. Based on a detailed transmission electron microscopy (TEM) microstructural characterization of the specimen material and on analyses of permeation data measured at temperatures ranging form 610 to 823 K for unannealed and annealed tungsten foil (25 μm thick), the authors note the following key results: deuterium transport in tungsten foil is dominated by extensive trapping that varies inversely with prior anneal temperatures of the foil material, the reduction in the trapped fraction correlates with a corresponding elimination of a high density of dislocations in cell-wall structures introduced during the foil fabrication process, trapping behavior in these foils can be modelled using trap energies between 1.3 eV and 1.5 eV and trap densities ranging from 1 x 10 -5 atom fraction

  13. The Use of Camera Traps in Wildlife

    Directory of Open Access Journals (Sweden)

    Yasin Uçarlı

    2013-11-01

    Full Text Available Camera traps are increasingly used in the abundance and density estimates of wildlife species. Camera traps are very good alternative for direct observation in case, particularly, steep terrain, dense vegetation covered areas or nocturnal species. The main reason for the use of camera traps is eliminated that the economic, personnel and time loss in a continuous manner at the same time in different points. Camera traps, motion and heat sensitive, can take a photo or video according to the models. Crossover points and feeding or mating areas of the focal species are addressed as a priority camera trap set locations. The population size can be finding out by the images combined with Capture-Recapture methods. The population density came out the population size divided to effective sampling area size. Mating and breeding season, habitat choice, group structures and survival rates of the focal species can be achieved from the images. Camera traps are very useful to obtain the necessary data about the particularly mysterious species with economically in planning and conservation efforts.

  14. The Electronic McPhail Trap

    Science.gov (United States)

    Potamitis, Ilyas; Rigakis, Iraklis; Fysarakis, Konstantinos

    2014-01-01

    Certain insects affect cultivations in a detrimental way. A notable case is the olive fruit fly (Bactrocera oleae (Rossi)), that in Europe alone causes billions of euros in crop-loss/per year. Pests can be controlled with aerial and ground bait pesticide sprays, the efficiency of which depends on knowing the time and location of insect infestations as early as possible. The inspection of traps is currently carried out manually. Automatic monitoring traps can enhance efficient monitoring of flying pests by identifying and counting targeted pests as they enter the trap. This work deals with the hardware setup of an insect trap with an embedded optoelectronic sensor that automatically records insects as they fly in the trap. The sensor responsible for detecting the insect is an array of phototransistors receiving light from an infrared LED. The wing-beat recording is based on the interruption of the emitted light due to the partial occlusion from insect's wings as they fly in the trap. We show that the recordings are of high quality paving the way for automatic recognition and transmission of insect detections from the field to a smartphone. This work emphasizes the hardware implementation of the sensor and the detection/counting module giving all necessary implementation details needed to construct it. PMID:25429412

  15. The Electronic McPhail Trap

    Directory of Open Access Journals (Sweden)

    Ilyas Potamitis

    2014-11-01

    Full Text Available Certain insects affect cultivations in a detrimental way. A notable case is the olive fruit fly (Bactrocera oleae (Rossi, that in Europe alone causes billions of euros in crop-loss/per year. Pests can be controlled with aerial and ground bait pesticide sprays, the efficiency of which depends on knowing the time and location of insect infestations as early as possible. The inspection of traps is currently carried out manually. Automatic monitoring traps can enhance efficient monitoring of flying pests by identifying and counting targeted pests as they enter the trap. This work deals with the hardware setup of an insect trap with an embedded optoelectronic sensor that automatically records insects as they fly in the trap. The sensor responsible for detecting the insect is an array of phototransistors receiving light from an infrared LED. The wing-beat recording is based on the interruption of the emitted light due to the partial occlusion from insect’s wings as they fly in the trap. We show that the recordings are of high quality paving the way for automatic recognition and transmission of insect detections from the field to a smartphone. This work emphasizes the hardware implementation of the sensor and the detection/counting module giving all necessary implementation details needed to construct it.

  16. Spectroscopy with trapped highly charged ions

    International Nuclear Information System (INIS)

    Beiersdorfer, Peter

    2009-01-01

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed; and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  17. Achieving Translationally Invariant Trapped Ion Rings

    Science.gov (United States)

    Urban, Erik; Li, Hao-Kun; Noel, Crystal; Hemmerling, Boerge; Zhang, Xiang; Haeffner, Hartmut

    2017-04-01

    We present the design and implementation of a novel surface ion trap design in a ring configuration. By eliminating the need for wire bonds through the use of electrical vias and using a rotationally invariant electrode configuration, we have realized a trap that is able to trap up to 20 ions in a ring geometry 45um in diameter, 400um above the trap surface. This large trapping height to ring diameter ratio allows for global addressing of the ring with both lasers and electric fields in the chamber, thereby increasing our ability to control the ring as a whole. Applying compensating electric fields, we measure very low tangential trap frequencies (less than 20kHz) corresponding to rotational barriers down to 4mK. This measurement is currently limited by the temperature of the ions but extrapolation indicates the barrier can be reduced much further with more advanced cooling techniques. Finally, we show that we are able to reduce this energy barrier sufficiently such that the ions are able to overcome it either through thermal motion or rotational motion and delocalize over the full extent of the ring. This work was funded by the Keck Foundation and the NSF.

  18. On-chip particle trapping and manipulation

    Science.gov (United States)

    Leake, Kaelyn Danielle

    The ability to control and manipulate the world around us is human nature. Humans and our ancestors have used tools for millions of years. Only in recent years have we been able to control objects at such small levels. In order to understand the world around us it is frequently necessary to interact with the biological world. Optical trapping and manipulation offer a non-invasive way to move, sort and interact with particles and cells to see how they react to the world around them. Optical tweezers are ideal in their abilities but they require large, non-portable, and expensive setups limiting how and where we can use them. A cheap portable platform is required in order to have optical manipulation reach its full potential. On-chip technology offers a great solution to this challenge. We focused on the Liquid-Core Anti-Resonant Reflecting Optical Waveguide (liquid-core ARROW) for our work. The ARROW is an ideal platform, which has anti-resonant layers which allow light to be guided in liquids, allowing for particles to easily be manipulated. It is manufactured using standard silicon manufacturing techniques making it easy to produce. The planner design makes it easy to integrate with other technologies. Initially I worked to improve the ARROW chip by reducing the intersection losses and by reducing the fluorescence and background on the ARROW chip. The ARROW chip has already been used to trap and push particles along its channel but here I introduce several new methods of particle trapping and manipulation on the ARROW chip. Traditional two beam traps use two counter propagating beams. A trapping scheme that uses two orthogonal beams which counter to first instinct allow for trapping at their intersection is introduced. This scheme is thoroughly predicted and analyzed using realistic conditions. Simulations of this method were done using a program which looks at both the fluidics and optical sources to model complex situations. These simulations were also used to

  19. Bait preference in basket trap fishing operation and heavy metal ...

    African Journals Online (AJOL)

    The bait preference of basket traps fishing operation and heavy metal contamination in the trap catches from Lagos Lagoon were carried out between January and June 2011. Sixty baskets traps were used for the fishing operation, twenty basket traps were baited each with soap, coconut and maize. Clibanarius africanus ...

  20. Evaluation of Sediment Trap Efficiency in an Estuarine Environment

    National Research Council Canada - National Science Library

    Stoddard, Daniel

    2001-01-01

    .... A second trap of same dimensions was also incorporated 420 m upstream. Trap efficiency was calculated as a sediment removal ratio, or the percentage by which influent sediment load to the trap is reduced in the effluent load from the trap...

  1. Description of the IMR Standard Light Trap and the Vertical ...

    African Journals Online (AJOL)

    The construction of different versions of a cheap, robust, and easy to operate light trap for catching various aquatic organisms is shown. The trap can be used to > 300 m depth and meets a number of criteria. Small-scale vertical distribution of decapod larvae was investigated during trap trials. The traps (6-10) were set for 24 ...

  2. 21 CFR 868.5995 - Tee drain (water trap).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tee drain (water trap). 868.5995 Section 868.5995...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5995 Tee drain (water trap). (a) Identification. A tee drain (water trap) is a device intended to trap and drain water that collects in ventilator...

  3. Deuterium trapping in carbon fiber composites under high fluence

    International Nuclear Information System (INIS)

    Airapetov, A.A.; Begrambekov, L.B.; Kuzmin, A.A.; Shigin, P.A.; Zakharov, A.M.

    2010-01-01

    The paper is devoted to investigation of deuterium trapping in CFC, dance graphite MPG-8 and pyrolytic graphite (PG) under plasma ion- and electron irradiation. Number of specific features of deuterium trapping and retention under plasma ion and electron irradiation is presented and discussed. In particular it is shown that 1) deuterium trapping takes place even when energy of impinging ions approaches zero; 2) deuterium is trapped under irradiation by plasma electrons; 3) under irradiation at equal fluences deuterium trapping is higher, when ion flux is smaller. High energy ion penetrating the surfaces are trapped in the traps created at the expense of their kinetic energy. The process may be named 'kinetic trapping'. Under low energy (smaller than 200 eV) electron and/or ion irradiation the energy of inelastic interaction on the surface provides creation of active centers, which initiate dissociation of deuterium sorbed on the surface, penetration of deuterium atoms into graphite and their trapping in specific low energy traps. The term 'potential trapping' is proposed for this type of trapping. Under high energy irradiation such atoms can fill the traps formed through kinetic mechanism. Origination of moveable deuterium atoms from the layer of surface sorption seems to be time dependent process and it is a reason of increase of trapping along with irradiation time. New features of deuterium trapping and retention in graphite evaluated in this study offer new opportunities for analysis and correct estimation of hydrogen isotope trapping and retention in tokamaks having graphite tiles. (authors)

  4. Tightly confined atoms in optical dipole traps

    International Nuclear Information System (INIS)

    Schulz, M.

    2002-12-01

    This thesis reports on the design and setup of a new atom trap apparatus, which is developed to confine few rubidium atoms in ultrahigh vacuum and make them available for controlled manipulations. To maintain low background pressure, atoms of a vapour cell are transferred into a cold atomic beam by laser cooling techniques, and accumulated by a magneto-optic trap (MOT) in a separate part of the vacuum system. The laser cooled atoms are then transferred into dipole traps made of focused far-off-resonant laser fields in single- or crossed-beam geometry, which are superimposed with the center of the MOT. Gaussian as well as hollow Laguerre-Gaussian (LG$ ( 01)$) beam profiles are used with red-detuned or blue-detuned light, respectively. Microfabricated dielectric phase objects allow efficient and robust mode conversion of Gaussian into Laguerre-Gaussian laser beams. Trap geometries can easily be changed due to the highly flexible experimental setup. The dipole trap laser beams are focused to below 10 microns at a power of several hundred milliwatts. Typical trap parameters, at a detuning of several ten nanometers from the atomic resonance, are trag depths of few millikelvin, trap frequencies near 30-kHz, trap light scattering rates of few hundred photons per atom and second, and lifetimes of several seconds. The number of dipole-trapped atoms ranges from more than ten thousand to below ten. The dipole-trapped atoms are detected either by a photon counting system with very efficient straylight discrimination, or by recapture into the MOT, which is imaged onto a sensitive photodiode and a CCD-camera. Due to the strong AC-Stark shift imposed by the high intensity trapping light, energy-selective resonant excitation and detection of the atoms is possible. The measured energy distribution is consistent with a harmonic potential shape and allows the determination of temperatures and heating rates. In first measurements, the thermal energy is found to be about 10 % of the

  5. (Anti)hydrogen recombination studies in a nested Penning trap

    International Nuclear Information System (INIS)

    Quint, W.; Kaiser, R.; Hall, D.; Gabrielse, G.

    1993-01-01

    Extremely cold antiprotons, stored in Penning trap at 4 K, open the way toward the production and study of cold antihydrogen. We have begun experimentally investigating the possibility to recombine cold positrons and antiprotons within nested Penning traps. Trap potentials are adjusted to allow cold trapped protons (and positive helium ions) to pass through cold trapped electrons. Electrons, protons and ions are counted by ejecting them to a cold channel plate and by nondestructive radiofrequency techniques. The effect of the space charge of one trapped species upon another trapped species passing through is clearly observed. (orig.)

  6. Optimising camera traps for monitoring small mammals.

    Directory of Open Access Journals (Sweden)

    Alistair S Glen

    Full Text Available Practical techniques are required to monitor invasive animals, which are often cryptic and occur at low density. Camera traps have potential for this purpose, but may have problems detecting and identifying small species. A further challenge is how to standardise the size of each camera's field of view so capture rates are comparable between different places and times. We investigated the optimal specifications for a low-cost camera trap for small mammals. The factors tested were 1 trigger speed, 2 passive infrared vs. microwave sensor, 3 white vs. infrared flash, and 4 still photographs vs. video. We also tested a new approach to standardise each camera's field of view. We compared the success rates of four camera trap designs in detecting and taking recognisable photographs of captive stoats (Mustelaerminea, feral cats (Felis catus and hedgehogs (Erinaceuseuropaeus. Trigger speeds of 0.2-2.1 s captured photographs of all three target species unless the animal was running at high speed. The camera with a microwave sensor was prone to false triggers, and often failed to trigger when an animal moved in front of it. A white flash produced photographs that were more readily identified to species than those obtained under infrared light. However, a white flash may be more likely to frighten target animals, potentially affecting detection probabilities. Video footage achieved similar success rates to still cameras but required more processing time and computer memory. Placing two camera traps side by side achieved a higher success rate than using a single camera. Camera traps show considerable promise for monitoring invasive mammal control operations. Further research should address how best to standardise the size of each camera's field of view, maximise the probability that an animal encountering a camera trap will be detected, and eliminate visible or audible cues emitted by camera traps.

  7. Flux trapping and shielding in irreversible superconductors

    International Nuclear Information System (INIS)

    Frankel, D.J.

    1978-05-01

    Flux trappings and shielding experiments were carried out on Pb, Nb, Pb-Bi, Nb-Sn, and Nb-Ti samples of various shapes. Movable Hall probes were used to measure fields near or inside the samples as a function of position and of applied field. The trapping of transverse multipole magnetic fields in tubular samples was accomplished by cooling the samples in an applied field and then smoothly reducing the applied field to zero. Transverse quadrupole and sextupole fields with gradients of over 2000 G/cm were trapped with typical fidelity to the original impressed field of a few percent. Transverse dipole fields of up to 17 kG were also trapped with similar fidelity. Shielding experiments were carried out by cooling the samples in zero field and then gradually applying an external field. Flux trapping and shielding abilities were found to be limited by two factors, the pinning strength of the material, and the susceptibility of a sample to flux jumping. The trapping and shielding behavior of flat disk samples in axial fields and thin-walled tubular samples in transverse fields was modeled. The models, which were based on the concept of the critical state, allowed a connection to be made between the pinning strength and critical current level, and the flux trapping and shielding abilities. Adiabatic and dynamic stability theories are discussed and applied to the materials tested. Good qualitative, but limited quantitative agreement was obtained between the predictions of the theoretical stability criteria and the observed flux jumping behavior

  8. Quantum information processing with trapped ions

    International Nuclear Information System (INIS)

    Haeffner, H.; Haensel, W.; Rapol, U.; Koerber, T.; Benhelm, J.; Riebe, M.; Chek-al-Kar, D.; Schmidt-Kaler, F.; Becher, C.; Roos, C.; Blatt, R.

    2005-01-01

    Single Ca + ions and crystals of Ca + ions are confined in a linear Paul trap and are investigated for quantum information processing. Here we report on recent experimental advancements towards a quantum computer with such a system. Laser-cooled trapped ions are ideally suited systems for the investigation and implementation of quantum information processing as one can gain almost complete control over their internal and external degrees of freedom. The combination of a Paul type ion trap with laser cooling leads to unique properties of trapped cold ions, such as control of the motional state down to the zero-point of the trapping potential, a high degree of isolation from the environment and thus a very long time available for manipulations and interactions at the quantum level. The very same properties make single trapped atoms and ions well suited for storing quantum information in long lived internal states, e.g. by encoding a quantum bit (qubit) of information within the coherent superposition of the S 1/2 ground state and the metastable D 5/2 excited state of Ca + . Recently we have achieved the implementation of simple algorithms with up to 3 qubits on an ion-trap quantum computer. We will report on methods to implement single qubit rotations, the realization of a two-qubit universal quantum gate (Cirac-Zoller CNOT-gate), the deterministic generation of multi-particle entangled states (GHZ- and W-states), their full tomographic reconstruction, the realization of deterministic quantum teleportation, its quantum process tomography and the encoding of quantum information in decoherence-free subspaces with coherence times exceeding 20 seconds. (author)

  9. Experimental apparatus to test air trap valves

    Science.gov (United States)

    Lemos De Lucca, Y. de F.; de Aquino, G. A.; Filho, J. G. D.

    2010-08-01

    It is known that the presence of trapped air within water distribution pipes can lead to irregular operation or even damage to the distribution systems and their components. The presence of trapped air may occur while the pipes are being filled with water, or while the pumping systems are in operation. The formation of large air pockets can produce the water hammer phenomenon, the instability and the loss of pressure in the water distribution networks. As a result, it can overload the pumps, increase the consumption of electricity, and damage the pumping system. In order to avoid its formation, all of the trapped air should be removed through "air trap valves". In Brazil, manufacturers frequently have unreliable sizing charts, which cause malfunctioning of the "air trap valves". The result of these malfunctions causes accidents of substantial damage. The construction of a test facility will provide a foundation of technical information that will be used to help make decisions when designing a system of pipelines where "air trap valves" are used. To achieve this, all of the valve characteristics (geometric, mechanic, hydraulic and dynamic) should be determined. This paper aims to describe and analyze the experimental apparatus and test procedure to be used to test "air trap valves". The experimental apparatus and test facility will be located at the University of Campinas, Brazil at the College of Civil Engineering, Architecture, and Urbanism in the Hydraulics and Fluid Mechanics laboratory. The experimental apparatus will be comprised of various components (pumps, steel pipes, butterfly valves to control the discharge, flow meter and reservoirs) and instrumentation (pressure transducers, anemometer and proximity sensor). It should be emphasized that all theoretical and experimental procedures should be defined while taking into consideration flow parameters and fluid properties that influence the tests.

  10. Experimental apparatus to test air trap valves

    Energy Technology Data Exchange (ETDEWEB)

    Lemos De Lucca, Y de F [CTH-DAEE-USP/FAAP/UNICAMP (Brazil); Aquino, G A de [SABESP/UNICAMP (Brazil); Filho, J G D, E-mail: yvone.lucca@gmail.co [Water Resources Department, University of Campinas-UNICAMP, Av. Albert Einstein, 951, Cidade Universitaria-Barao Geraldo-Campinas, S.P., 13083-852 (Brazil)

    2010-08-15

    It is known that the presence of trapped air within water distribution pipes can lead to irregular operation or even damage to the distribution systems and their components. The presence of trapped air may occur while the pipes are being filled with water, or while the pumping systems are in operation. The formation of large air pockets can produce the water hammer phenomenon, the instability and the loss of pressure in the water distribution networks. As a result, it can overload the pumps, increase the consumption of electricity, and damage the pumping system. In order to avoid its formation, all of the trapped air should be removed through 'air trap valves'. In Brazil, manufacturers frequently have unreliable sizing charts, which cause malfunctioning of the 'air trap valves'. The result of these malfunctions causes accidents of substantial damage. The construction of a test facility will provide a foundation of technical information that will be used to help make decisions when designing a system of pipelines where 'air trap valves' are used. To achieve this, all of the valve characteristics (geometric, mechanic, hydraulic and dynamic) should be determined. This paper aims to describe and analyze the experimental apparatus and test procedure to be used to test 'air trap valves'. The experimental apparatus and test facility will be located at the University of Campinas, Brazil at the College of Civil Engineering, Architecture, and Urbanism in the Hydraulics and Fluid Mechanics laboratory. The experimental apparatus will be comprised of various components (pumps, steel pipes, butterfly valves to control the discharge, flow meter and reservoirs) and instrumentation (pressure transducers, anemometer and proximity sensor). It should be emphasized that all theoretical and experimental procedures should be defined while taking into consideration flow parameters and fluid properties that influence the tests.

  11. Optimization of multifunnel traps for emerald ash borer (Coleoptera: Buprestidae): influence of size, trap coating, and color.

    Science.gov (United States)

    Francese, Joseph A; Rietz, Michael L; Mastro, Victor C

    2013-12-01

    Field assays were conducted in southeastern and south-central Michigan in 2011 and 2012 to optimize green and purple multifunnel (Lindgren funnel) traps for use as a survey tool for the emerald ash borer, Agrilus planipennis Fairmaire. Larger sized (12- and 16-unit) multifunnel traps caught more beetles than their smaller-sized (4- and 8-unit) counterparts. Green traps coated with untinted (white) fluon caught almost four times as many adult A. planipennis as Rain-X and tinted (green) fluon-coated traps and almost 33 times more beetles than untreated control traps. Purple multifunnel traps generally caught much lower numbers of A. planipennis adults than green traps, and trap catch on them was not affected by differences in the type of coating applied. However, trap coating was necessary as untreated control purple traps caught significantly less beetles than traps treated with Rain-X and untinted or tinted (purple) fluon. Proportions of male beetles captured were generally much higher on green traps than on purple traps, but sex ratios were not affected by trap coating. In 2012, a new shade of purple plastic, based on a better color match to an attractive purple paint than the previously used purple, was used for trapping assays. When multifunnel traps were treated with fluon, green traps caught more A. planipennis adults than both shades of purple and a prism trap that was manufactured based on the same color match. Trap catch was not affected by diluting the fluon concentration applied to traps to 50% (1:1 mixture in water). At 10%, trap catch was significantly lowered.

  12. Trapping and dark current in plasma-based accelerators

    International Nuclear Information System (INIS)

    Schroder, C.B.; Esarey, E.; Shadwick, B.A.; Leemans, W.P.

    2004-01-01

    The trapping of thermal electrons in a nonlinear plasma wave of arbitrary phase velocity is investigated. The threshold plasma wave amplitude for trapping plasma electrons is calculated, thereby determining the fraction trapped and the expected dark current in a plasma-based accelerator. It is shown that the presence of a laser field (e.g., trapping in the self-modulated regime of the laser wakefield accelerator) increases the trapping threshold. Implications for experimental and numerical laser-plasma studies are discussed

  13. Trapping and Evolution Dynamics of Ultracold Two-Component Plasmas

    International Nuclear Information System (INIS)

    Choi, J.-H.; Knuffman, B.; Zhang, X. H.; Povilus, A. P.; Raithel, G.

    2008-01-01

    We demonstrate the trapping of a strongly magnetized, quasineutral ultracold plasma in a nested Penning trap with a background field of 2.9 T. Electrons remain trapped in this system for several milliseconds. Early in the evolution, the dynamics are driven by a breathing-mode oscillation in the ionic charge distribution, which modulates the electron trap depth. Over longer times scales, the electronic component undergoes cooling. Trap loss resulting from ExB drift is characterized

  14. Dynamic analysis of trapping and escaping in dual beam optical trap

    Science.gov (United States)

    Li, Wenqiang; Hu, Huizhu; Su, Heming; Li, Zhenggang; Shen, Yu

    2016-10-01

    In this paper, we simulate the dynamic movement of a dielectric sphere in optical trap. This dynamic analysis can be used to calibrate optical forces, increase trapping efficiency and measure viscous coefficient of surrounding medium. Since an accurate dynamic analysis is based on a detailed force calculation, we calculate all forces a sphere receives. We get the forces of dual-beam gradient radiation pressure on a micron-sized dielectric sphere in the ray optics regime and utilize Einstein-Ornstein-Uhlenbeck to deal with its Brownian motion forces. Hydrodynamic viscous force also exists when the sphere moves in liquid. Forces from buoyance and gravity are also taken into consideration. Then we simulate trajectory of a sphere when it is subject to all these forces in a dual optical trap. From our dynamic analysis, the sphere can be trapped at an equilibrium point in static water, although it permanently fluctuates around the equilibrium point due to thermal effects. We go a step further to analyze the effects of misalignment of two optical traps. Trapping and escaping phenomena of the sphere in flowing water are also simulated. In flowing water, the sphere is dragged away from the equilibrium point. This dragging distance increases with the decrease of optical power, which results in escaping of the sphere with optical power below a threshold. In both trapping and escaping process we calculate the forces and position of the sphere. Finally, we analyze a trapping region in dual optical tweezers.

  15. Spatial mismatch between sea lamprey behaviour and trap location explains low success at trapping for control

    Science.gov (United States)

    Rous, Andrew M.; McLean, Adrienne R.; Barber, Jessica; Bravener, Gale; Castro-Santos, Theodore; Holbrook, Christopher M.; Imre, Istvan; Pratt, Thomas C.; McLaughlin, Robert L.

    2017-01-01

    Crucial to the management of invasive species is understanding space use and the environmental features affecting space use. Improved understanding of space use by invasive sea lamprey (Petromyzon marinus) could help researchers discern why trap success in large rivers is lower than needed for effective control. We tested whether manipulating discharge nightly could increase trap success at a hydroelectric generating station on the St. Marys River. We quantified numbers of acoustically tagged sea lampreys migrating up to, and their space use at, the hydroelectric generating station. In 2011 and 2012, 78% and 68%, respectively, of tagged sea lampreys reached the generating station. Sea lampreys were active along the face, but more likely to occur at the bottom and away from the traps near the surface, especially when discharge was high. Our findings suggest that a low probability of encountering traps was due to spatial (vertical) mismatch between space use by sea lamprey and trap locations and that increasing discharge did not alter space use in ways that increased trap encounter. Understanding space use by invasive species can help managers assess the efficacy of trapping and ways of improving trapping success.

  16. Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation

    International Nuclear Information System (INIS)

    Charles Doret, S; Amini, Jason M; Wright, Kenneth; Volin, Curtis; Killian, Tyler; Ozakin, Arkadas; Denison, Douglas; Hayden, Harley; Pai, C-S; Slusher, Richart E; Harter, Alexa W

    2012-01-01

    Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled dc electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on dc electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains. (paper)

  17. A tunable narrow-line-width multi-wavelength Er-doped fiber laser based on a high birefringence fiber ring mirror and an auto-tracking filter

    Science.gov (United States)

    Jia, Xiu-jie; Liu, Yan-ge; Si, Li-bin; Guo, Zhan-cheng; Fu, Sheng-gui; Kai, Gui-yun; Dong, Xiao-yi

    2008-01-01

    A novel multi-wavelength erbium-doped fiber laser operating in C-band is proposed and successfully demonstrated. The wavelength interval between the wavelengths is about 0.22 nm. The 3 dB bandwidth of the laser is about 0.012 nm, and the output power reaches 4.8 mW. By using a high birefringence fiber ring mirror (HiBi-FLM) and a tunable FBG, the laser realizes switchable and tunable characteristic. The mode hopping can be effectively prevented. Moreover, this laser can improve wavelength stability significantly by taking advantage of an un-pumped Er3+-doped fiber at the standing-wave section. The laser can operate in stable narrow-line-width with single-, dual-wavelength, and unstable triple-wavelength output at room temperature.

  18. Importance of Interfacial Interactions to Access Shear Elasticity of Liquids and Understand Flow Induced Birefringence from Liquid Crystals to Worm-Like Micellar Solutions

    Directory of Open Access Journals (Sweden)

    Noirez Laurence

    2017-03-01

    Full Text Available This work points out the importance of the substrate boundary conditions to lower the dissipation in the dynamic measurement and access the closest dynamic characteristics of liquids, in particular to access the low frequency shear elasticity. The liquid/surface interface is a source of dissipation that enters and impacts the measurement. Examples of steady-state shear flows or flow birefringence are presented to highlight the non-universality of the behavior with respect to the nature of the substrate or the sheared thickness. Additionally the present development completes and extends the identification of low frequency shear elasticity made at sub-millimeter gaps in various one-component liquids to salt-free aqueous solutions (CTAB-water (Hexadecyl-TrimethylAmmonium Bromide.

  19. A density functional theory study of magneto-electric Jones birefringence of noble gases, furan homologues, and mono-substituted benzenes

    International Nuclear Information System (INIS)

    Fahleson, Tobias; Norman, Patrick; Coriani, Sonia; Rizzo, Antonio; Rikken, Geert L. J. A.

    2013-01-01

    We report on the results of a systematic ab initio study of the Jones birefringence of noble gases, of furan homologues, and of monosubstituted benzenes, in the gas phase, with the aim of analyzing the behavior and the trends within a list of systems of varying size and complexity, and of identifying candidates for a combined experimental/theoretical study of the effect. We resort here to analytic linear and nonlinear response functions in the framework of time-dependent density functional theory. A correlation is made between the observable (the Jones constant) and the atomic radius for noble gases, or the permanent electric dipole and a structure/chemical reactivity descriptor as the para Hammett constant for substituted benzenes

  20. Trapping for invasive crayfish: comparisons of efficacy and selectivity of baited traps versus novel artificial refuge traps

    Directory of Open Access Journals (Sweden)

    Green Nicky

    2018-01-01

    Full Text Available Non-native crayfish can dominate the invertebrate biomass of invaded freshwaters, with their high ecological impacts resulting in their populations being controlled by numerous methods, especially trapping. Although baited funnel traps (BTs are commonly used, they tend to be selective in mainly catching large-bodied males. Here, the efficacy and selectivity of BTs were tested against an alternative trapping method based on artificial refuges (ARTs that comprised of a metal base with several tubes (refuges attached. The target species was signal crayfish Pacifastacus leniusculus in an upland river in southwest England. Trapping was completed in April to October over two consecutive years. In total, 5897 crayfish were captured, with 87% captured in ARTs. Comparison of the catch per unit effort (CPUE between the trapping methods in the same 24 hour periods revealed significantly higher CPUE in ARTs than of BTs. ARTs fished for 6 consecutive days had higher catches than both methods over 24 hours. Whilst catches in BTs were significantly dominated by males (1.49M:1F, the sex ratio of catches in ARTs was 0.99M:1F. The mean carapace length of crayfish was also significantly larger in BTs (43.2 ± 0.6 mm than in ARTs (33.6 ± 0.2 mm. Thus, ARTs had higher CPUE over 24 hour and 6 day periods versus BTs and also captured a greater proportion of smaller and female individuals. These results indicate that when trapping methods are deployed for managing invasions, the use of ARTs removes substantial numbers of crayfish of both sexes and of varying body sizes.