WorldWideScience

Sample records for full field birefringence

  1. (Full field) optical coherence tomography and applications

    Science.gov (United States)

    Buchroithner, Boris; Hannesschläger, Günther; Leiss-Holzinger, Elisabeth; Prylepa, Andrii; Heise, Bettina

    2018-03-01

    This paper illustrates specific features and use of optical coherence tomography (OCT) in the raster-scanning and in comparison in the full field version of this imaging technique. Cases for nondestructive testing are discussed alongside other application schemes. In particular monitoring time-dependent processes and probing of birefringent specimens are considered here. In the context of polymer testing birefringence mapping may often provide information about internal strain and stress states. Recent results obtained with conventional raster-scanning OCT systems, with (dual and single-shot) full field OCT configurations, and with polarization-sensitive versions of (full field) OCT are presented here.

  2. Electric field-induced transient birefringence and light scattering of synthetic liposomes.

    Science.gov (United States)

    Asgharian, N; Schelly, Z A

    1999-05-12

    The dynamics of electric field-induced transient birefringence Deltan(t) and light scattering (detected as turbidity) of 190 nm diameter unilamellar vesicles of dioleoylphosphatidylcholine are investigated as a function of applied field strength E, length of the square pulse Deltat, lipid concentration, mean hydrodynamic diameter , ionic strength, and temperature. Generally, induced birefringence exclusively is observed at low lipid concentration and below certain threshold values of E and Deltat, whereas concomitant induced turbidity appears at high lipid concentration and above thresholds values of E and Deltat. Turbidity is monitored through the change in transmitted intensity DeltaS parallel(t) and DeltaS perpendicular(t) of light polarized parallel and perpendicular to the applied field E. The field-induced structural changes are reflected in double-exponential forward relaxation and triple-exponential reverse relaxation of the positive birefringence, and in non-exponential relaxations of DeltaS parallel (t) and DeltaS perpendicular(t). Under the field, the associated physical events are interpreted as elongation of the spherical bilayer shells in the direction of E, linear chain formation (pearling) of the induced dipolar liposomes parallel to E, and partial fusion of adjoining vesicles within the chains. Under conditions where electroporation can be detected, pore opening succeeds the elongation of the vesicles. After termination of the field, the vesicles return to their original time average spherical shape, the oriented chains randomize and disintegrate, and the fused structures are converted either to unilamellar or multilamellar vesicles.

  3. Alignment of bicelles studied with high-field magnetic birefringence and small-angle neutron scattering measurements.

    Science.gov (United States)

    Liebi, Marianne; van Rhee, Peter G; Christianen, Peter C M; Kohlbrecher, Joachim; Fischer, Peter; Walde, Peter; Windhab, Erich J

    2013-03-12

    Birefringence measurements at high magnetic field strength of up to 33 T were used to detect magnetically induced alignment of bicelles composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), cholesterol, and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-diethylenetriaminepentaacetate (DMPE-DTPA) with complexed lanthanide ions. These birefringence measurements together with a small-angle neutron scattering (SANS) analysis in a magnetic field showed parallel alignment of the bicelles if the lanthanide was thulium (Tm(3+)), and perpendicular alignment with dysprosium (Dy(3+)). With the birefringence measurements, the order parameter S can be determined as a function of the magnetic field strength, if the magnetic alignment reaches saturation. Additional structural information can be obtained if the maximum induced birefringence is considered. The degree of alignment of the studied bicelles increased with decreasing temperature from 40 to 5 °C and showed a new bicellar structure comprising a transient hole formation at intermediate temperatures (20 °C) during heating from 5 to 40 °C.

  4. 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.)

  5. Open source software for electric field Monte Carlo simulation of coherent backscattering in biological media containing birefringence.

    Science.gov (United States)

    Radosevich, Andrew J; Rogers, Jeremy D; Capoğlu, Ilker R; Mutyal, Nikhil N; Pradhan, Prabhakar; Backman, Vadim

    2012-11-01

    ABSTRACT. We present an open source electric field tracking Monte Carlo program to model backscattering in biological media containing birefringence, with computation of the coherent backscattering phenomenon as an example. These simulations enable the modeling of tissue scattering as a statistically homogeneous continuous random media under the Whittle-Matérn model, which includes the Henyey-Greenstein phase function as a special case, or as a composition of discrete spherical scatterers under Mie theory. The calculation of the amplitude scattering matrix for the above two cases as well as the implementation of birefringence using the Jones N-matrix formalism is presented. For ease of operator use and data processing, our simulation incorporates a graphical user interface written in MATLAB to interact with the underlying C code. Additionally, an increase in computational speed is achieved through implementation of message passing interface and the semi-analytical approach. Finally, we provide demonstrations of the results of our simulation for purely scattering media and scattering media containing linear birefringence.

  6. Microscopic Observation of Ferroelectric Domains in SrTiO3 Using Birefringence Imaging Techniques under High Electric Fields

    Science.gov (United States)

    Manaka, Hirotaka; Nozaki, Hirofumi; Miura, Yoko

    2017-11-01

    Phase transitions in SrTiO3 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 LiNbO3 with varying electric field, distributions of the electric field in the sample stage were found to be negligible. In SrTiO3, 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.

  7. 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)

  8. 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...

  9. 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.

  10. Polarized light field microscopy: an analytical method using a microlens array to simultaneously capture both conoscopic and orthoscopic views of birefringent objects.

    Science.gov (United States)

    Oldenbourg, R

    2008-09-01

    For the comprehensive analysis of anisotropic materials, a new approach, called 'polarized light field microscopy' is introduced. It uses an LC-PolScope to which a microlens array was added at the image plane of the objective lens. The system is patterned after the 'light field microscope' that achieves both lateral and axial resolution in thick specimens in a single camera exposure. In polarized light field microscopy, the microlens array generates a hybrid image consisting of an array of small conoscopic images, each sampling a different object area. Analysis of the conoscopic images reveals the birefringence of each object area as a function of the propagation direction of transmitted light rays. The principles and utility of the instrument that we are calling 'light field LC-PolScope' are demonstrated with images of a thin, polycrystalline calcite film, revealing the azimuth and inclination angle of the optic axis for many crystals simultaneously, including crystals with diameters as small as 2 microm. Compared to traditional conoscopy and related methods, the vastly improved throughput and quantitative analysis afforded by the light field LC-PolScope make it the instrument of choice for measuring 3D birefringence parameters of complex structures.

  11. Polarized light field microscopy: an analytical method using a microlens array to simultaneously capture both conoscopic and orthoscopic views of birefringent objects

    Science.gov (United States)

    Oldenbourg, Rudolf

    2008-01-01

    For the comprehensive analysis of anisotropic materials, a new approach, called “polarized light field microscopy” is introduced. It uses an LC-PolScope to which a microlens array was added at the image plane of the objective lens. The system is patterned after the “light field microscope” that achieves both lateral and axial resolution in thick specimens in a single camera exposure. In polarized light field microscopy, the microlens array generates a hybrid image consisting of an array of small conoscopic images, each sampling a different object area. Analysis of the conoscopic images reveals the birefringence of each object area as a function of the propagation direction of transmitted light rays. The principles and utility of the instrument that we are calling “light field LC-PolScope” are demonstrated with images of a thin, polycrystalline calcite film, revealing the azimuth and inclination angle of the optic axis for many crystals simultaneously, including crystals with diameters as small as 2 µm. Compared to traditional conoscopy and related methods, the vastly improved throughput and quantitative analysis afforded by the light field LC-PolScope make it the instrument of choice for measuring 3-dimensional birefringence parameters of complex structures. PMID:18754996

  12. China exported birefringent filter

    Science.gov (United States)

    Li, Ting; Mao, Weijun; Lu, Haitian; Zhu, Yong

    2001-09-01

    Since 1960s, Nanjing Astronomical Instrument Research center of CAS have been developing the birefringent filters for China solar observatories, the most famous one in the world is the 0.15Å(0.12Å)/5324Å(4861Å) filter for the 35cm Solar Magnetic Field Telescope of the Huairou Solar Station of Beijing Observatory. The big success in the field of Lyot filter has been proved by the international solar physics circle, since 1988, Japanese and Korean astronomers have been paying a lot of orders for making Lyot filters from China, up to now we have exported 11 sets of such sophisticated optical instruments, they have been used for routine solar observations in the observatories and planetaria in the two countries. We also begin to repair old Lyot filters made by Germany and France from foreign countries, as India and Germany.

  13. Full wave-field reflection coefficient inversion.

    Science.gov (United States)

    Dettmer, Jan; Dosso, Stan E; Holland, Charles W

    2007-12-01

    This paper develops a Bayesian inversion for recovering multilayer geoacoustic (velocity, density, attenuation) profiles from a full wave-field (spherical-wave) seabed reflection response. The reflection data originate from acoustic time series windowed for a single bottom interaction, which are processed to yield reflection coefficient data as a function of frequency and angle. Replica data for inversion are computed using a wave number-integration model to calculate the full complex acoustic pressure field, which is processed to produce a commensurate seabed response function. To address the high computational cost of calculating short range acoustic fields, the inversion algorithms are parallelized and frequency averaging is replaced by range averaging in the forward model. The posterior probability density is interpreted in terms of optimal parameter estimates, marginal distributions, and credibility intervals. Inversion results for the full wave-field seabed response are compared to those obtained using plane-wave reflection coefficients. A realistic synthetic study indicates that the plane-wave assumption can fail, producing erroneous results with misleading uncertainty bounds, whereas excellent results are obtained with the full-wave reflection inversion.

  14. Full-field OCT: applications in ophthalmology

    Science.gov (United States)

    Grieve, Kate; Dubois, Arnaud; Paques, Michel; Le Gargasson, Jean-Francois; Boccara, Albert C.

    2005-04-01

    We present images of ocular tissues obtained using ultrahigh resolution full-field OCT. The experimental setup is based on the Linnik interferometer, illuminated by a tungsten halogen lamp. En face tomographic images are obtained in real-time without scanning by computing the difference of two phase-opposed interferometric images recorded by a high-resolution CCD camera. A spatial resolution of 0.7 μm × 0.9 μm (axial × transverse) is achieved thanks to the short source coherence length and the use of high numerical aperture microscope objectives. A detection sensitivity of 90 dB is obtained by means of image averaging and pixel binning. Whole unfixed eyes and unstained tissue samples (cornea, lens, retina, choroid and sclera) of ex vivo rat, mouse, rabbit and porcine ocular tissues were examined. The unprecedented resolution of our instrument allows cellular-level resolution in the cornea and retina, and visualization of individual fibers in the lens. Transcorneal lens imaging was possible in all animals, and in albino animals, transscleral retinal imaging was achieved. We also introduce our rapid acquisition full-field optical coherence tomography system designed to accommodate in vivo ophthalmologic imaging. The variations on the original system technology include the introduction of a xenon arc lamp as source, and rapid image acquisition performed by a high-speed CMOS camera, reducing acquisition time to 5 ms per frame.

  15. Current challenges of full field digital mammography

    International Nuclear Information System (INIS)

    Van Ongeval, C.; Bosmans, H.; Van Steen, A.

    2005-01-01

    Full field digital mammography (FFDM) has advantages over screen-film mammography (SFM), but some important challenges remain. The first challenge is related to the specific characteristics of FFDM. It remains unclear, which shape and limiting values of the modulation transfer function have the most influence on the performance of a detector, such as the effect of the image display on the overall image quality and the effect of processing on cancer detection. In order to assess the image quality of FFDM, we have set up a scoring system. The second challenge is related to screening mammography: is the quality of an image the same when it is viewed on different monitors and with different processing algorithms? Is Computer Aided Diagnosis necessary in a screening environment? In FFDM, the effect of different detectors, processing and display possibilities on the image and on cancer detection are not clearly investigated. (authors)

  16. Nearly-off-axis transmissivity of Solc birefringent filters.

    Science.gov (United States)

    Zhou, Yu; Liu, Liren; Zhang, Juan; Liu, De'an; Luan, Zhu

    2003-04-01

    The characteristics of light propagating near the axis of a birefringent filter are studied. A generalized formulation to describe the nearly-off-axis transmissivity of a Solc birefringent filter is derived. On this basis, the polarization conoscopic figures of Solc filters with different numbers of birefringent plates are simulated. Furthermore the variation of spectral transmission with angle of incidence is analyzed, and the field-of-view transmissivity and the spectral transmissivity averaged with respect to the spread of incident light are given. Primary experiments for verification are also demonstrated.

  17. High Frequency Modulation Method for Measuring of Birefringence

    Directory of Open Access Journals (Sweden)

    Šulc M.

    2013-05-01

    Full Text Available A method of optical birefringence measurement is presented. It uses an el ectro-optic modulator for the high frequency modulation of polarization of the laser beam. The developed optical apparatus exhibits high sensitivity. It is able to measure very small birefringence of samples down to 10-3 rad. The accuracy and sensitivity of the method was checked by measurement of calibrated Sol eil – Babi net compensator. Method can be also used for online and accurate measurement of an optical components birefringence. This application was developed with the aim to measure Cotton-Mouton effect in air and nitrogen.

  18. 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.

  19. 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.

  20. 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

  1. Birefringence characterization of injection molded microplates

    Science.gov (United States)

    Adhikari, Achyut; Asundi, Anand

    2015-03-01

    Birefringence affects the quality of image analysis in injection molded micro-plates. Depending upon their manufacturing / production processes and the type of material, different plates exhibit varying amounts of birefringence. This birefringence is attributed to residual stress generated during the molding process. Polarimeter is the standard tool for birefringence distribution visualization and quantification. Broad chemical resistance and high mechanical stability of the plates are the desirable properties that can be characterized by birefringence measurement. Birefringence, expressed in nm/cm is light retardance (nm) after passing through a sample with certain thickness (cm). Low or uniform birefringence plates provide high-resolution demonstrating higher performance, hence suitable for bio-chemical analysis.

  2. 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)

  3. Highly birefringent elliptical core photonic crystal fiber for terahertz application

    Science.gov (United States)

    Sultana, Jakeya; Islam, Md. Saiful; Faisal, Mohammad; Islam, Mohammad Rakibul; Ng, Brian W.-H.; Ebendorff-Heidepriem, Heike; Abbott, Derek

    2018-01-01

    We present a novel strategy for designing a highly birefringent photonic crystal fiber (PCF) with near zero flattened dispersion properties by applying elliptical air holes in the core area. The elliptical structure of the air holes in the porous-core region introduces asymmetry between x and y polarization modes, which consequently offers ultra-high birefringence. Also the compact geometry of the conventional hexagonal structure in the cladding confines most of the useful power. The optical properties including birefringence, dispersion, confinement loss, effective material loss (EML) and single modeness of the fiber are investigated using a full-vector finite element method. Simulation results show an ultra-high birefringence of 0 . 086 ultra-flattened near zero dispersion of 0 . 53 ± 0 . 07 ps/THz/cm in a broad frequency range. The practical implementation of the proposed fiber is feasible using existing fabrication technology and is applicable to the areas of terahertz sensing and polarization maintaining systems.

  4. Detection of sinkholes or anomalies using full seismic wave fields.

    Science.gov (United States)

    2013-04-01

    This research presents an application of two-dimensional (2-D) time-domain waveform tomography for detection of embedded sinkholes and anomalies. The measured seismic surface wave fields were inverted using a full waveform inversion (FWI) technique, ...

  5. 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.

  6. Calibration and validation of full-field techniques

    Directory of Open Access Journals (Sweden)

    Thalmann R.

    2010-06-01

    Full Text Available We review basic metrological terms related to the use of measurement equipment for verification of numerical model calculations. We address three challenges that are faced when performing measurements in experimental mechanics with optical techniques: the calibration of a measuring instrument that (i measures strain values, (ii provides full-field data, and (iii is dynamic.

  7. Dynamical Birefringence: Electron-Hole Recollisions as Probes of Berry Curvature

    Directory of Open Access Journals (Sweden)

    Hunter B. Banks

    2017-11-01

    Full Text Available The direct measurement of Berry phases is still a great challenge in condensed-matter systems. The bottleneck has been the ability to adiabatically drive an electron coherently across a large portion of the Brillouin zone in a solid where the scattering is strong and complicated. We break through this bottleneck and show that high-order sideband generation (HSG in semiconductors is intimately affected by Berry phases. Electron-hole recollisions and HSG occur when a near-band-gap laser beam excites a semiconductor that is driven by sufficiently strong terahertz-frequency electric fields. We carry out experimental and theoretical studies of HSG from three GaAs/AlGaAs quantum wells. The observed HSG spectra contain sidebands up to the 90th order, to our knowledge the highest-order optical nonlinearity reported in solids. The highest-order sidebands are associated with electron-hole pairs driven coherently across roughly 10% of the Brillouin zone around the Γ point. The principal experimental claim is a dynamical birefringence: the intensity and polarization of the sidebands depend on the relative polarization of the exciting near-infrared (NIR and the THz electric fields, as well as on the relative orientation of the laser fields with the crystal. We explain dynamical birefringence by generalizing the three-step model for high-order harmonic generation. The hole accumulates Berry phases due to variation of its internal state as the quasimomentum changes under the THz field. Dynamical birefringence arises from quantum interference between time-reversed pairs of electron-hole recollision pathways. We propose a method to use dynamical birefringence to measure Berry curvature in solids.

  8. Volumetric breast density estimation from full-field digital mammograms.

    NARCIS (Netherlands)

    Engeland, S. van; Snoeren, P.R.; Huisman, H.J.; Boetes, C.; Karssemeijer, N.

    2006-01-01

    A method is presented for estimation of dense breast tissue volume from mammograms obtained with full-field digital mammography (FFDM). The thickness of dense tissue mapping to a pixel is determined by using a physical model of image acquisition. This model is based on the assumption that the breast

  9. 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....

  10. Full-field measurements and identification in solid mechanics

    CERN Document Server

    Grediac, Michel

    2008-01-01

    This timely book presents cutting-edge developments by experts in the field on the rapidly developing and scientifically challenging area of full-field measurement techniques used in solid mechanics - including photoelasticity, grid methods, deflectometry, holography, speckle interferometry and digital image correlation. The evaluation of strains and the use of the measurements in subsequent parameter identification techniques to determine material properties are also presented. Since parametric identification techniques require a close coupling of theoretical models and experimental measurements, the book focuses on specific modeling approaches that include finite element model updating, the equilibrium gap method, constitutive equation gap method, virtual field method and reciprocity gap method. In the latter part of the book, the authors discuss two particular applications of selected methods that are of special interest to many investigators: the analysis of localized phenomenon and connections between mi...

  11. Birefringent neutron prisms for spin echo scattering angle measurement

    Science.gov (United States)

    Pynn, Roger; Fitzsimmons, M. R.; Lee, W. T.; Stonaha, P.; Shah, V. R.; Washington, A. L.; Kirby, B. J.; Majkrzak, C. F.; Maranville, B. B.

    2009-09-01

    In the first decade of the 19th century, an English chemist, William Wollaston, invented an arrangement of birefringent prisms that splits a beam of light into two spatially separated beams with orthogonal polarizations. We have constructed similar devices for neutrons using triangular cross-section solenoids and employed them for Spin Echo Scattering Angle Measurement (SESAME). A key difference between birefringent neutron prisms and their optical analogues is that it is hard to embed the former in a medium which has absolutely no birefringence because this implies the removal of all magnetic fields. We have overcome this problem by using the symmetry properties of the Wollaston neutron prisms and of the overall spin echo arrangement. These symmetries cause a cancellation of Larmor phase aberrations and provide robust coding of neutron scattering angles with simple equipment.

  12. Full-Field Indentation Damage Measurement Using Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    Elías López-Alba

    2017-07-01

    Full Text Available A novel approach based on full-field indentation measurements to characterize and quantify the effect of contact in thin plates is presented. The proposed method has been employed to evaluate the indentation damage generated in the presence of bending deformation, resulting from the contact between a thin plate and a rigid sphere. For this purpose, the 3D Digital Image Correlation (3D-DIC technique has been adopted to quantify the out of plane displacements at the back face of the plate. Tests were conducted using aluminum thin plates and a rigid bearing sphere to evaluate the influence of the thickness and the material behavior during contact. Information provided by the 3D-DIC technique has been employed to perform an indirect measurement of the contact area during the loading and unloading path of the test. A symmetrical distribution in the contact damage region due to the symmetry of the indenter was always observed. In the case of aluminum plates, the presence of a high level of plasticity caused shearing deformation as the load increased. Results show the full-field contact damage area for different plates’ thicknesses at different loads. The contact damage region was bigger when the thickness of the specimen increased, and therefore, bending deformation was reduced. With the proposed approach, the elastic recovery at the contact location was quantified during the unloading, as well as the remaining permanent indentation damage after releasing the load. Results show the information obtained by full-field measurements at the contact location during the test, which implies a substantial improvement compared with pointwise techniques.

  13. Normalized noise power spectrum of full field digital mammography system

    International Nuclear Information System (INIS)

    Norriza Mohd Isa; Wan Muhamad Saridan Wan Hassan

    2009-01-01

    A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through detrending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality. (Author)

  14. Full spectrum of Lyapunov exponents in gauge field theories

    International Nuclear Information System (INIS)

    Biro, T.S.; Markum, H.; Pullirsch, R.

    2003-01-01

    Full text: Results are presented for the full spectrum of Lyapunov exponents of the compact U(1) gauge system in classical field theory. Instead of the determination of the largest Lyapunov exponent by the rescaling method we now use the monodromy matrix approach. The Lyapunov spectrum L i is expressed in terms of the eigenvalues Λ i of the monodromy matrix M. In the confinement phase the eigenvalues lie on either the real or on the imaginary axes. This is a nice illustration of a strange attractor of a chaotic system. Positive Lyapunov exponents eject the trajectories from oscillating orbits provided by the imaginary eigenvalues. Negative Lyapunov exponents attract the trajectories keeping them confined in the basin. Latest studies concern the time (in)dependence of the monodromy matrix. Further, we show that monopoles are created and annihilated in pairs as a function of real time in access to a fixed average monopole number. (author)

  15. 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.

  16. 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

  17. Quantification of breast arterial calcification using full field digital mammography

    International Nuclear Information System (INIS)

    Molloi, Sabee; Xu Tong; Ducote, Justin; Iribarren, Carlos

    2008-01-01

    Breast arterial calcification is commonly detected on some mammograms. Previous studies indicate that breast arterial calcification is evidence of general atherosclerotic vascular disease and it may be a useful marker of coronary artery disease. It can potentially be a useful tool for assessment of coronary artery disease in women since mammography is widely used as a screening tool for early detection of breast cancer. However, there are currently no available techniques for quantification of calcium mass using mammography. The purpose of this study was to determine whether it is possible to quantify breast arterial calcium mass using standard digital mammography. An anthropomorphic breast phantom along with a vessel calcification phantom was imaged using a full field digital mammography system. Densitometry was used to quantify calcium mass. A calcium calibration measurement was performed at each phantom thickness and beam energy. The known (K) and measured (M) calcium mass on 5 and 9 cm thickness phantoms were related by M=0.964K-0.288 mg (r=0.997 and SEE=0.878 mg) and M=1.004K+0.324 mg (r=0.994 and SEE=1.32 mg), respectively. The results indicate that accurate calcium mass measurements can be made without correction for scatter glare as long as careful calcium calibration is made for each breast thickness. The results also indicate that composition variations and differences of approximately 1 cm between calibration phantom and breast thickness introduce only minimal error in calcium measurement. The uncertainty in magnification is expected to cause up to 5% and 15% error in calcium mass for 5 and 9 cm breast thicknesses, respectively. In conclusion, a densitometry technique for quantification of breast arterial calcium mass was validated using standard full field digital mammography. The results demonstrated the feasibility and potential utility of the densitometry technique for accurate quantification of breast arterial calcium mass using standard digital

  18. Electric birefringence and streaming-electric birefringence of synthesized imogolite: the anisotropy of electric polarizability.

    Science.gov (United States)

    Matsumoto, Mitsuhiro; Koibuchi, Sae; Hayashi, Naoki

    2007-04-15

    Imogolite synthesized from sodium orthosilicate and aluminum trichloride was fractionated into four fractions by centrifuging at 12,000 x g (1h). The supernatant, which did not deposit by three times centrifugations, was used for all measurements. The signal of birefringence under a reversing electric pulse showed that the permanent dipole moment is negligibly small at low fields. The electric birefringence under a rectangular electric pulse is positive. The saturated value is proportional to the concentration of imogolite in the range of 0-0.1mg/ml and decreases rapidly with an increase of added salt concentration for NaCl and AgNO(3). It slightly depends on the pH of solution and is biggest in pure water. Then we have determined the anisotropy of electric polarizability (Deltaalpha) for imogolite in pure water at 0.05 mg/ml. Deltaalpha we obtained from the method decreases rapidly at low fields and slowly at high fields as shown in references [M. Matsumoto, Colloids Surf. A 148 (1999) 75, M. Matsumoto, Biophys. Chem. 58 (1996) 173]. It is approximately shown by the following expression, Deltaalpha=Deltaalpha(infinity)+(Deltaalpha(0)-Deltaalpha(infinity))/(1+KE), (Deltaalpha(0):Deltaalpha at E=0, Deltaalpha(infinity):Deltaalpha at E=infinity). Using this relation we can draw the curve of electric birefringence as a function of electric field and compare it with experimental values. The results, when Deltaalpha(0)=1.17x10(-28)Fm(2), Deltaalpha(infinity)=0.005x10(-28)Fm(2) and K=0.00031 m/V, are in good agreement with each other. In order to explain the reason why the anisotropy of electric polarizability rapidly decreases with an increase of electric field we propose that the difference of electrophoretic mobility between parts of colloidal particle causes the orientation of a rod like particle. The theoretical electric birefringence as a function of electric field we obtained is considerably in good agreement with the experimental values.

  19. Cylindrical Field Effect Transistor: A Full Volume Inversion Device

    KAUST Repository

    Fahad, Hossain M.

    2010-12-01

    The increasing demand for high performance as well as low standby power devices has been the main reason for the aggressive scaling of conventional CMOS transistors. Current devices are at the 32nm technology node. However, due to physical limitations as well as increase in short-channel effects, leakage, power dissipation, this scaling trend cannot continue and will eventually hit a barrier. In order to overcome this, alternate device topologies have to be considered altogether. Extensive research on ultra thin body double gate FETs and gate all around nanowire FETs has shown a lot of promise. Under strong inversion, these devices have demonstrated increased performance over their bulk counterparts. This is mainly attributed to full carrier inversion in the body. However, these devices are still limited by lithographic and processing challenges making them unsuitable for commercial production. This thesis explores a unique device structure called the CFET (Cylindrical Field Effect Transistors) which also like the above, relies on complete inversion of carriers in the body/bulk. Using dual gates; an outer and an inner gate, full-volume inversion is possible with benefits such as enhanced drive currents, high Ion/Ioff ratios and reduced short channel effects.

  20. The Virtual Fields Method Extracting Constitutive Mechanical Parameters from Full-field Deformation Measurements

    CERN Document Server

    Pierron, Fabrice

    2012-01-01

    The Virtual Fields Method: Extracting Constitutive Mechanical Parameters from Full-field Deformation Measurements is the first book on the Virtual Fields Method (VFM), a technique to identify materials mechanical properties from full-field measurements. Firmly rooted with extensive theoretical description of the method, the book presents numerous examples of application to a wide range of materials (composites, metals, welds, biomaterials) and situations (static, vibration, high strain rate). The authors give a detailed training section with examples of progressive difficulty to lead the reader to program the VFM and include a set of commented Matlab programs as well as GUI Matlab-based software for more general situations. The Virtual Fields Method: Extracting Constitutive Mechanical Parameters from Full-field Deformation Measurements is an ideal book for researchers, engineers, and students interested in applying the VFM to new situations motivated by their research.  

  1. Spectral analysis of full field digital mammography data

    International Nuclear Information System (INIS)

    Heine, John J.; Velthuizen, Robert P.

    2002-01-01

    The spectral content of mammograms acquired from using a full field digital mammography (FFDM) system are analyzed. Fourier methods are used to show that the FFDM image power spectra obey an inverse power law; in an average sense, the images may be considered as 1/f fields. Two data representations are analyzed and compared (1) the raw data, and (2) the logarithm of the raw data. Two methods are employed to analyze the power spectra (1) a technique based on integrating the Fourier plane with octave ring sectioning developed previously, and (2) an approach based on integrating the Fourier plane using rings of constant width developed for this work. Both methods allow theoretical modeling. Numerical analysis indicates that the effects due to the transformation influence the power spectra measurements in a statistically significant manner in the high frequency range. However, this effect has little influence on the inverse power law estimation for a given image regardless of the data representation or the theoretical analysis approach. The analysis is presented from two points of view (1) each image is treated independently with the results presented as distributions, and (2) for a given representation, the entire image collection is treated as an ensemble with the results presented as expected values. In general, the constant ring width analysis forms the foundation for a spectral comparison method for finding spectral differences, from an image distribution sense, after applying a nonlinear transformation to the data. The work also shows that power law estimation may be influenced due to the presence of noise in the higher frequency range, which is consistent with the known attributes of the detector efficiency. The spectral modeling and inverse power law determinations obtained here are in agreement with that obtained from the analysis of digitized film-screen images presented previously. The form of the power spectrum for a given image is approximately 1/f 2

  2. Volumetric breast density estimation from full-field digital mammograms.

    Science.gov (United States)

    van Engeland, Saskia; Snoeren, Peter R; Huisman, Henkjan; Boetes, Carla; Karssemeijer, Nico

    2006-03-01

    A method is presented for estimation of dense breast tissue volume from mammograms obtained with full-field digital mammography (FFDM). The thickness of dense tissue mapping to a pixel is determined by using a physical model of image acquisition. This model is based on the assumption that the breast is composed of two types of tissue, fat and parenchyma. Effective linear attenuation coefficients of these tissues are derived from empirical data as a function of tube voltage (kVp), anode material, filtration, and compressed breast thickness. By employing these, tissue composition at a given pixel is computed after performing breast thickness compensation, using a reference value for fatty tissue determined by the maximum pixel value in the breast tissue projection. Validation has been performed using 22 FFDM cases acquired with a GE Senographe 2000D by comparing the volume estimates with volumes obtained by semi-automatic segmentation of breast magnetic resonance imaging (MRI) data. The correlation between MRI and mammography volumes was 0.94 on a per image basis and 0.97 on a per patient basis. Using the dense tissue volumes from MRI data as the gold standard, the average relative error of the volume estimates was 13.6%.

  3. Using magnetic birefringence to determine the molecular arrangement of supramolecular nanostructures

    International Nuclear Information System (INIS)

    Gielen, Jeroen C; Shklyarevskiy, Igor O; Christianen, Peter C M; Maan, J C; Schenning, Albertus P H J

    2009-01-01

    Supramolecular aggregates can be aligned in solution using a magnetic field. Because of the optical anisotropy of the molecular building blocks, the alignment results in an anisotropic refractive index of the solution parallel and perpendicular to the magnetic field. We present a model for calculating the magnetic birefringence, using solely the magnetic susceptibilities and optical polarizabilities of the molecules, for any molecular arrangement. We demonstrate that magnetic birefringence is a very sensitive tool for determining the molecular organization within supramolecular aggregates.

  4. 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

  5. Measurement of full-field deformation induced by a dc electrical field in organic insulator films

    Directory of Open Access Journals (Sweden)

    Boudou L.

    2010-06-01

    Full Text Available Digital image correlation method (DIC using the correlation coefficient curve-fitting for full-field surface deformation measurements of organic insulator films is investigated in this work. First the validation of the technique was undertaken. The computer-generated speckle images and the measurement of coefficient of thermal expansion (CTE of aluminium are used to evaluate the measurement accuracy of the technique. In a second part the technique is applied to measure the mechanical deformation induced by electrical field application to organic insulators. For that Poly(ethylene naphthalene 2,6-dicarboxylate (PEN thin films were subjected to DC voltage stress and DIC provides the full-field induced deformations of the test films. The obtained results show that the DIC is a practical and robust tool for better comprehension of mechanical behaviour of the organic insulator films under electrical stress.

  6. Phase and birefringence aberration correction

    Science.gov (United States)

    Bowers, M.; Hankla, A.

    1996-07-09

    A Brillouin enhanced four wave mixing phase conjugate mirror corrects phase aberrations of a coherent electromagnetic beam and birefringence induced upon that beam. The stimulated Brillouin scattering (SBS) phase conjugation technique is augmented to include Brillouin enhanced four wave mixing (BEFWM). A seed beam is generated by a main oscillator which arrives at the phase conjugate cell before the signal beams in order to initiate the Brillouin effect. The signal beam which is being amplified through the amplifier chain is split into two perpendicularly polarized beams. One of the two beams is chosen to be the same polarization as some component of the seed beam, the other orthogonal to the first. The polarization of the orthogonal beam is then rotated 90{degree} such that it is parallel to the other signal beam. The three beams are then focused into cell containing a medium capable of Brillouin excitation. The two signal beams are focused such that they cross the seed beam path before their respective beam waists in order to achieve BEFWM or the two signal beams are focused to a point or points contained within the focused cone angle of the seed beam to achieve seeded SBS, and thus negate the effects of all birefringent and material aberrations in the system. 5 figs.

  7. 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.

  8. Birefringence (spin rotation and spin dichroism) of high-energy deuterons

    International Nuclear Information System (INIS)

    Baryshevskij, V.G.; Rovba, A.A.

    2016-01-01

    The phenomenon of birefringence (spin rotation and spin dichroism) of high-energy deuterons, currently observed in experiments, is the macroscopic quantum effect similar to the birefringence effect known in optics. This paper considers the contribution coming to the spin dichroism effect from the interaction of deuteron electric quadrupole moment and nuclear electric field. The effect proves to be responsive to the behavior of deuteron ground state wave functions at a small distance. [ru

  9. Full Field Birefringence Measurement of Grown-In Stresses in Thin Silicon Sheet: Final Technical Report, 2 January 2002 - 15 January 2008

    Energy Technology Data Exchange (ETDEWEB)

    Danyluk, S.; Ostapenka, S.

    2008-11-01

    This paper summarizes polariscopy work that led to prototype non-contact, near-infrared light-transmission system for inspecting thin, flat, large-area Si wafers. Acoustic work led to commercially viable system to inspect wafers for microcracks.

  10. Field and laboratory investigations for full depth reclamation projects.

    Science.gov (United States)

    2011-03-01

    Full-depth reclamation (FDR) offers a timely, cost-effective solution to restore a pavements condition. : However, FDR represents only one technique in the engineers toolkit available for addressing deteriorating : pavement conditions. The purp...

  11. Model and Full Scale Predictions of a Carrier Flow Field

    National Research Council Canada - National Science Library

    Gorski, Joseph

    2002-01-01

    .... These calculations are for a bare hull with skeg, bilge keels and outboard propeller shaft. The calculations indicate there are extensive differences between the model and full scale wakes entering the propeller disks...

  12. Vortex ring state by full-field actuator disc model

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, J.N.; Shen, W.Z.; Munduate, X. [DTU, Dept. of Energy Engineering, Lyngby (Denmark)

    1997-08-01

    One-dimensional momentum theory provides a simple analytical tool for analysing the gross flow behavior of lifting propellers and rotors. Combined with a blade-element strip-theory approach, it has for many years been the most popular model for load and performance predictions of wind turbines. The model works well at moderate and high wind velocities, but is not reliable at small wind velocities, where the expansion of the wake is large and the flow field behind the rotor dominated by turbulent mixing. This is normally referred to as the turbulent wake state or the vortex ring state. In the vortex ring state, momentum theory predicts a decrease of thrust whereas the opposite is found from experiments. The reason for the disagreement is that recirculation takes place behind the rotor with the consequence that the stream tubes past the rotor becomes effectively chocked. This represents a condition at which streamlines no longer carry fluid elements from far upstream to far downstream, hence one-dimensional momentum theory is invalid and empirical corrections have to be introduced. More sophisticated analytical or semi-analytical rotor models have been used to describe stationary flow fields for heavily loaded propellers. In recent years generalized actuator disc models have been developed, but up to now no detailed computations of the turbulent wake state or the vortex ring state have been performed. In the present work the phenomenon is simulated by direct simulation of the Navier-Stokes equations, where the influence of the rotor on the flow field is modelled simply by replacing the blades by an actuator disc with a constant normal load. (EG) 13 refs.

  13. Development of hard X-ray dark-field microscope using full-field optics

    International Nuclear Information System (INIS)

    Takano, Hidekazu; Azuma, Hiroaki; Shimomura, Sho; Tsuji, Takuya; Tsusaka, Yoshiyuki; Kagoshima, Yasushi

    2016-01-01

    We develop a dark-field X-ray microscope using full-field optics based on a synchrotron beamline. Our setup consists of a condenser system and a microscope objective with an angular acceptance larger than that of the condenser. The condenser system is moved downstream from its regular position such that the focus of the condenser is behind the objective. The dark-field microscope optics are configured by excluding the converging beam from the condenser at the focal point. The image properties of the system are evaluated by observing and calculating a Siemens star test chart with 10 keV X-rays. Our setup allows easy switching to bright-field imaging. (author)

  14. Image-domain full waveform inversion: Field data example

    KAUST Repository

    Zhang, Sanzong

    2014-08-05

    The main difficulty with the data-domain full waveform inversion (FWI) is that it tends to get stuck in the local minima associated with the waveform misfit function. This is the result of cycle skipping which degrades the low-wavenumber update in the absence of low-frequencies and long-offset data. An image-domain objective function is defined as the normed difference between the predicted and observed common image gathers (CIGs) in the subsurface offset domain. This new objective function is not constrained by cycle skipping at the far subsurface offsets. To test the effectiveness of this method, we apply it to marine data recorded in the Gulf of Mexico. Results show that image-domain FWI is less sensitive to the initial model and the absence of low-frequency data compared with conventional FWI. The liability, however, is that it is almost an order of magnitude more expensive than standard FWI.

  15. Zero birefringence films of pullulan ester derivatives

    Science.gov (United States)

    Danjo, Takahiro; Enomoto, Yukiko; Shimada, Hikaru; Nobukawa, Shogo; Yamaguchi, Masayuki; Iwata, Tadahisa

    2017-04-01

    High-performance films with almost zero-birefringence and zero-wavelength dispersion were succeeded to prepare from pullulan esters derivatives (PLEs) without any additives. Optical transmittance analysis, birefringence measurement of PLE cast film and hot stretched films, and infrared dichroism analysis were conducted to characterize optical properties of PLE films comparing with cellulose triacetate which is commercially used as low-birefringence in optical devices. The aims of this study, characterization of optical properties of pullulan esters, can develop a deep understanding of the fundamental knowing and applicability of polysaccharides. Accordingly, authors believe this paper will open the gate for researches in the application of polysaccharides.

  16. 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.

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

    Indian Academy of Sciences (India)

    odinger equation modelling fourth order dispersion effects when the linearly polarized pump is oriented at arbitrary angles with respect to the slow and fast axes of the birefringent fiber. Keywords. Birefringent optical fiber; fourth order dispersion; ...

  18. Influence of the Wavelength Dependence of Birefringence in the Generation of Supercontinuum and Dispersive Wave in Fiber Optics

    Directory of Open Access Journals (Sweden)

    Rodrigo Acuna Herrera

    2017-01-01

    Full Text Available In this paper, we perform numerical analysis about the influence of the wavelength dependence of birefringence (WDB in the Supercontinuum (SC and dispersive wave (DW generation. We study different birefringence profiles such as constant, linear, and parabolic. We see that, for a linear and parabolic profile, the generation of SC practically does not change, while this does so when the constant value of the birefringence varies. Similar situation happens with the generation of dispersive waves. In addition, we observe that the broadband of the SC increases when the Stimulated Raman Scattering (SRS is neglected for all WDB profiles.

  19. Birefringence in a chiral medium, via temporal cloaking

    Science.gov (United States)

    Khan, Humayun; Haneef, Muhammad

    2017-05-01

    This paper reports theoretical investigation of birefringence in a chiral medium for the creation of temporal cloaking. The chiral medium splits the input probe beam into left/right circular polarized beams. These left/right circular polarized beams are then controlled and modified within the chiral medium. The left circular polarized beam delays by 24 ns whereas the right circular polarized beam advances by  -23 ns at a control field of rabbi frequency 6γ . This opens a 47 ns time gap for temporal cloaking to hide information without noise corruption and energy loss. The results have potential applications in communication devices for secure propagation of light pulse.

  20. ANALYSIS OF INDEXED-GUIDED HIGHLY BIREFRINGENT ...

    African Journals Online (AJOL)

    ABSTRACT. 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 ...

  1. ANSYS-based birefringence property analysis of side-hole fiber induced by pressure and temperature

    Science.gov (United States)

    Zhou, Xinbang; Gong, Zhenfeng

    2017-12-01

    In this paper, we theoretically investigate the influences of pressure and temperature on the birefringence property of side-hole fibers with different shapes of holes using the finite element analysis method. A physical mechanism of the birefringence of the side-hole fiber is discussed with the presence of different external pressures and temperatures. The strain field distribution and birefringence values of circular-core, rectangular-core, and triangular-core side-hole fibers are presented. Our analysis shows the triangular-core side-hole fiber has low temperature sensitivity which weakens the cross sensitivity of temperature and strain. Additionally, an optimized structure design of the side-hole fiber is presented which can be used for the sensing application.

  2. ANSYS-based birefringence property analysis of side-hole fiber induced by pressure and temperature

    Science.gov (United States)

    Zhou, Xinbang; Gong, Zhenfeng

    2018-03-01

    In this paper, we theoretically investigate the influences of pressure and temperature on the birefringence property of side-hole fibers with different shapes of holes using the finite element analysis method. A physical mechanism of the birefringence of the side-hole fiber is discussed with the presence of different external pressures and temperatures. The strain field distribution and birefringence values of circular-core, rectangular-core, and triangular-core side-hole fibers are presented. Our analysis shows the triangular-core side-hole fiber has low temperature sensitivity which weakens the cross sensitivity of temperature and strain. Additionally, an optimized structure design of the side-hole fiber is presented which can be used for the sensing application.

  3. Temperature sensibility of the birefringence properties in side-hole photonic crystal fiber filled with Indium

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Vera, Erick, E-mail: erickreyes@itm.edu.co; Gómez-Cardona, Nelson D. [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840 Medellín (Colombia); Facultad de Ingeniería, Instituto Tecnológico Metropolitano, A.A. 54954 Medellín (Colombia); Chesini, Giancarlo; Cordeiro, Cristiano M. B. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas-UNICAMP, Campinas, SP (Brazil); Torres, Pedro [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840 Medellín (Colombia)

    2014-11-17

    We report on the temperature sensitivity of the birefringence properties of a special kind of photonic crystal fiber containing two side holes filled with Indium metal. The modulation of the fiber birefringence is accomplished through the stress field induced by the expansion of the metal. Although the fiber was made at low gas pressures during the indium infiltration process, the birefringence showed anomalous property at a relatively low temperature value, which is completely different from those reported in conventional-like fibers with two holes filled with metal. By modeling the anisotropic changes induced by the metal expansion to the refractive index within the fiber, we are able to reproduce the experimental results. Our results have practical relevance for the design of devices based on this technology.

  4. Investigating compression failure mechanisms in composite laminates with a transient fiberglass-epoxy birefringent material

    Science.gov (United States)

    Shuart, M. J.; Williams, J. G.

    1984-01-01

    An experimental study is reported in which a nondestructive technique involving the use of a transparent fiberglass-epoxy composite birefringent material has been used to investigate compression failure mechanisms in graphite-epoxy laminates. It is shown that the birefringency and transparency of the fiberglass-epoxy material permits regions of high stress to be located and the mechanisms of local failure propagation to be identified within the laminate. The material may also be useful for studying stress fields and for identifying failure initiation and propagation mechanisms in a wide variety of composite-structure problems.

  5. Investigation of Dispersion and Performance Based on Ring Cavity by Birefringent Interleaver for DWDM Transmission Systems

    Directory of Open Access Journals (Sweden)

    Tsair-Chun Liang

    2013-01-01

    Full Text Available We theoretically investigate a 25 GHz multichannel filter based on ring cavity birefringent optical interleaver for dense wavelength division multiplexing (DWDM transmission systems. The simulation tool used in this work is the Advanced System Analysis Program (ASAP optical modeling software. We improve the dispersion performance by employing λ/6 and λ/4 wave plates as birefringent compensators for interleavers. The new structure exhibits a high performance with nearly zero ripple, a channel isolation greater than 102 dB, and a passband utilization of 86% within the C-band. The research results illustrate that our modified scheme can improve the dispersion of more than 76.6% in comparison with the previous studies of optical interleaver with birefringent crystal and ring cavity structures.

  6. Cosmic birefringence fluctuations and cosmic microwave background B-mode polarization

    Directory of Open Access Journals (Sweden)

    Seokcheon Lee

    2015-06-01

    Full Text Available Recently, BICEP2 measurements of the cosmic microwave background (CMB B-mode polarization has indicated the presence of primordial gravitational waves at degree angular scales, inferring the tensor-to-scalar ratio of r=0.2 and a running scalar spectral index, provided that dust contamination is low. In this Letter, we show that the existence of the fluctuations of cosmological birefringence can give rise to CMB B-mode polarization that fits BICEP2 data with r<0.11 and no running of the scalar spectral index. When dust contribution is taken into account, we derive an upper limit on the cosmological birefringence, Aβ2<0.0075, where A is the amplitude of birefringence fluctuations that couple to electromagnetism with a coupling strength β.

  7. 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.

  8. Birefringent all-solid hybrid microstructured fiber.

    Science.gov (United States)

    Goto, Ryuichiro; Jackson, Stuart D; Fleming, Simon; Kuhlmey, Boris T; Eggleton, Benjamin J; Himeno, Kuniharu

    2008-11-10

    We report the characterization of a birefringent all-solid hybrid microstructured fiber, in which the core-modes are guided by both the photonic bandgap (PBG) effect and total internal reflection (TIR). Due to the twofold symmetry, modal birefringence of 1.5 x 10(-4) and group birefringence of 2.1 x 10(-4) were measured at 1.31 microm, which is in the middle of the second bandgap. The band structure was calculated to be different from conventional 2-D PBG fibers due to the 1-D arrangement of high-index regions. The bend loss has a strong directional dependence due to the coexistence of the two guiding mechanisms. The fiber has two important properties pertinent to PBG fibers; spectral filtering, and chromatic dispersion specific to PBG fibers. The number of high-index regions, which trap pump power (by index guiding) when the fiber is used in cladding-pumped fiber lasers, is greatly reduced so that this fiber should enable efficient cladding pumping. This structure is suitable for linearly-polarized, cladding-pumped fiber lasers utilizing the properties of PBG fibers.

  9. Comparison of Photopic Negative Response of Full-Field and Focal Electroretinograms in Detecting Glaucomatous Eyes

    Directory of Open Access Journals (Sweden)

    Shigeki Machida

    2011-01-01

    Full Text Available Purpose. To compare the photopic negative response (PhNR of the full-field electroretinogram (ERG to the PhNR of the focal ERGs in detecting glaucoma. Methods. One hundred and three eyes with glaucoma and 42 normal eyes were studied. Full-field ERGs were elicited by red stimuli on a blue background. The focal ERGs were elicited by a 15∘ white stimulus spot centered on the macula, the superotemporal or the inferotemporal areas of the macula. Results. In early glaucoma, the areas under the receiver operating characteristic curves (AUCs were significantly larger for the focal PhNR (0.863–0.924 than those for the full-field PhNR (0.666–0.748 (P<.05. The sensitivity was significantly higher for the focal PhNR than for the full-field PhNR in early (P<.01 and intermediate glaucoma (P<.05. In advanced glaucoma, there was no difference in the AUCs and sensitivities between the focal and full-field PhNRs. Conclusions. The focal ERG has the diagnostic ability with higher sensitivity in detecting early and intermediate glaucoma than the full-field ERG.

  10. Identification of the electroelastic coupling from full multi-physical fields measured at the micrometre scale

    DEFF Research Database (Denmark)

    Amiot, Fabien; Hild, F.; Kanoufi, F.

    2007-01-01

    coupling and to identify the spatial charge density distribution from full-field phase measurements. Minimizing the least-squares gap between the measured phase and a statically admissible phase field, the mechanical effect is found to be charge-driven. The charge density field is also found to be singular...... on the cantilever edge, and the shear stress versus charge density is found to be non-linear....

  11. Detecting strain in birefringent materials using spectral polarimetry

    Science.gov (United States)

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

  12. Three dimensional birefringence control using nanoparticles for uniaxially oriented films

    Science.gov (United States)

    Takatoh, Kohki; Goda, Kazuya; Akimoto, Mitsuhiro; Abo, Tomohiro

    2017-07-01

    In uniaxially stretched films, the refractive indices perpendicular to the stretching direction have the same value, and so, the out-of-plane birefringence is half that of the in-plane birefringence. This means that these values cannot be controlled independently in uniaxially stretched films. The same relationship was previously observed when needle-shaped nanoparticles were added to uniaxially stretched films. This paper presents a method to achieve the three-dimensional birefringence control of uniaxially stretched films. When we added plate-shaped smectite nanoparticles to uniaxially stretched films, different relationships were observed for the in- and out-of-plane birefringence. The magnitude of the out-of-plane birefringence increased more than would be expected according to the usual relationship. According to our results, uniaxially stretched films with no out-of-plane birefringence and negative in-plane birefringence can be formed by adding smectite nanoparticles to polymer films with negative in-plane birefringence. Using our method, the three-dimensional birefringence of uniaxial polymers can be controlled, and the possibility of the uniaxial films could be drastically extended.

  13. Terahertz birefringence of potassium niobate crystals

    Science.gov (United States)

    Antsygin, V. D.; Mamrashev, A. A.; Nikolaev, N. A.

    2018-03-01

    We present terahertz optical properties (refractive indices and absorption coefficients) of potassium niobate crystals measured by time-domain spectroscopy in the range of 0.2-2.0 THz. We observe average refractive indices nx = 5.25, ny = 4.8, nz = 5.9 for corresponding optical axes X, Y, Z with the large birefringence of Δn = nz - ny = 1.1. We report rising absorption coefficient at higher frequencies (α ∼ 50 cm-1 at 1 THz for all three axes) while the dichroism is not pronounced. Somewhat higher absorption compared to the previous results could be attributed to some polydomain structure remaining in the crystal.

  14. J-Integral Calculation by Finite Element Processing of Measured Full-Field Surface Displacements

    OpenAIRE

    Barhli, S. M.; Mostafavi, Mahmoud; Cinar, Ahmet; Hollis, David; Marrow, James

    2017-01-01

    © 2017 The Author(s)A novel method has been developed based on the conjoint use of digital image correlation to measure full field displacements and finite element simulations to extract the strain energy release rate of surface cracks. In this approach, a finite element model with imported full-field displacements measured by DIC is solved and the J-integral is calculated, without knowledge of the specimen geometry and applied loads. This can be done even in a specimen that develops crack ti...

  15. 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 ...

  16. Cross-phase modulational instability in an elliptical birefringent fiber ...

    Indian Academy of Sciences (India)

    Cross-phase modulational instability in an elliptical birefringent fiber with higher order nonlinearity and dispersion. R Ganapathy V C Kuriakose. Research Articles Volume 58 Issue 4 April 2002 pp 669- ... Keywords. Cross-phase modulational instability; normal dispersion; group velocity mismatch; birefringent optical fiber.

  17. 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...

  18. Modelling birefringence in isolated elliptical core photonic crystal fibers

    DEFF Research Database (Denmark)

    Nielsen, Martin Dybendal; Vienne, Guillaume; Jensen, Jacob Riis

    2001-01-01

    A simple model for calculation of the birefringence in asymmetric isolated core PCFs employing approximation with an ellipsoid suspended in air is presented. Birefringence values in the order of 10-2 are obtained and comparison with both calculations based on a SEM picture of a real fiber...

  19. 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)

  20. Full-field hard x-ray microscopy with interdigitated silicon lenses

    DEFF Research Database (Denmark)

    Simons, Hugh; Stöhr, Frederik; Michael-Lindhard, Jonas

    2016-01-01

    Full-field x-ray microscopy using x-ray objectives has become a mainstay of the biological and materials sciences. However, the inefficiency of existing objectives at x-ray energies above 15 keV has limited the technique to weakly absorbing or two-dimensional (2D) samples. Here, we show that sign...

  1. A Two-Mode Mean-Field Optimal Switching Problem for the Full Balance Sheet

    Directory of Open Access Journals (Sweden)

    Boualem Djehiche

    2014-01-01

    a two-mode optimal switching problem of mean-field type, which can be described by a system of Snell envelopes where the obstacles are interconnected and nonlinear. The main result of the paper is a proof of a continuous minimal solution to the system of Snell envelopes, as well as the full characterization of the optimal switching strategy.

  2. Constraints on Particles and Fields from Full Stokes Observations of AGN

    Directory of Open Access Journals (Sweden)

    Daniel C. Homan

    2018-01-01

    Full Text Available Combined polarization imaging of radio jets from Active Galactic Nuclei (AGN in circular and linear polarization, also known as full Stokes imaging, has the potential to constrain both the magnetic field structure and particle properties of jets. Although only a small fraction of the emission when detected, typically less than a few tenths of a percent but up to as much as a couple of percent in the strongest resolved sources, circular polarization directly probes the magnetic field and particles within the jet itself and is not expected to be modified by external screens. A key to using full Stokes observations to constrain jet properties is obtaining a better understanding of the emission of circular polarization, including its variability and spectrum. We discuss what we have learned so far from parsec scale monitoring observations in the MOJAVE program and from multi-frequency observations of selected AGN.

  3. Exploring Direct 3D Interaction for Full Horizontal Parallax Light Field Displays Using Leap Motion Controller

    Directory of Open Access Journals (Sweden)

    Vamsi Kiran Adhikarla

    2015-04-01

    Full Text Available This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

  4. 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....

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

    Science.gov (United States)

    Lyngsø, J K; Mangan, B J; Olausson, C B; Roberts, P J

    2010-06-21

    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 310(-5) m(-1).

  6. Hard X-ray full field microscopy and magnifying microtomography using compound refractive lenses

    CERN Document Server

    Schrör, C; Benner, B; Kuhlmann, M; Tümmler, J; Lengeler, B; Rau, C; Weitkamp, T; Snigirev, A; Snigireva, I

    2001-01-01

    For hard X-rays, parabolic compound refractive lenses (PCRLs) are genuine imaging devices like glass lenses for visible light. Based on these new lenses, a hard X-ray full field microscope has been constructed that is ideally suited to image the interior of opaque samples with a minimum of sample preparation. As a result of a large depth of field, CRL micrographs are sharp projection images of most samples. To obtain 3D information about a sample, tomographic techniques are combined with magnified imaging.

  7. Applications of Hard X-ray Full-Field Transmission X-ray Microscopy at SSRL

    Science.gov (United States)

    Liu, Y.; Andrews, J. C.; Meirer, F.; Mehta, A.; Gil, S. Carrasco; Sciau, P.; Mester, Z.; Pianetta, P.

    2011-09-01

    State-of-the-art hard x-ray full-field transmission x-ray microscopy (TXM) at beamline 6-2C of Stanford Synchrotron Radiation Lightsource has been applied to various research fields including biological, environmental, and material studies. With the capability of imaging a 32-micron field-of-view at 30-nm resolution using both absorption mode and Zernike phase contrast, the 3D morphology of yeast cells grown in gold-rich media was investigated. Quantitative evaluation of the absorption coefficient was performed for mercury nanoparticles in alfalfa roots exposed to mercury. Combining XANES and TXM, we also performed XANES-imaging on an ancient pottery sample from the Roman pottery workshop at LaGraufesenque (Aveyron).

  8. A domain decomposition approach for full-field measurements based identification of local elastic parameters

    KAUST Repository

    Lubineau, Gilles

    2015-03-01

    We propose a domain decomposition formalism specifically designed for the identification of local elastic parameters based on full-field measurements. This technique is made possible by a multi-scale implementation of the constitutive compatibility method. Contrary to classical approaches, the constitutive compatibility method resolves first some eigenmodes of the stress field over the structure rather than directly trying to recover the material properties. A two steps micro/macro reconstruction of the stress field is performed: a Dirichlet identification problem is solved first over every subdomain, the macroscopic equilibrium is then ensured between the subdomains in a second step. We apply the method to large linear elastic 2D identification problems to efficiently produce estimates of the material properties at a much lower computational cost than classical approaches.

  9. Full-field wrist pulse signal acquisition and analysis by 3D Digital Image Correlation

    Science.gov (United States)

    Xue, Yuan; Su, Yong; Zhang, Chi; Xu, Xiaohai; Gao, Zeren; Wu, Shangquan; Zhang, Qingchuan; Wu, Xiaoping

    2017-11-01

    Pulse diagnosis is an essential part in four basic diagnostic methods (inspection, listening, inquiring and palpation) in traditional Chinese medicine, which depends on longtime training and rich experience, so computerized pulse acquisition has been proposed and studied to ensure the objectivity. To imitate the process that doctors using three fingertips with different pressures to feel fluctuations in certain areas containing three acupoints, we established a five dimensional pulse signal acquisition system adopting a non-contacting optical metrology method, 3D digital image correlation, to record the full-field displacements of skin fluctuations under different pressures. The system realizes real-time full-field vibration mode observation with 10 FPS. The maximum sample frequency is 472 Hz for detailed post-processing. After acquisition, the signals are analyzed according to the amplitude, pressure, and pulse wave velocity. The proposed system provides a novel optical approach for digitalizing pulse diagnosis and massive pulse signal data acquisition for various types of patients.

  10. Evaluation of full field automated photoelastic analysis based on phase stepping

    Science.gov (United States)

    Haake, S. J.; Wang, Z. F.; Patterson, E. A.

    A full-field automated polariscope designed for photoelastic analysis and based on the method of phase-stepping is described. The system is evaluated through the analysis of five different photoelastic models using both the automated system and using manual analysis employing the Tardy Compensation method. Models were chosen to provide a range of different fringe patterns, orders, and stress gradients and were: a disk in diametral compression, a constrained beam subject to a point load, a tensile plate with a central hole, a turbine blade, and a turbine disk slot. The repeatability of the full-field system was found to compare well with point by point systems. The worst isochromatic error was approximately 0.007 fringes, and the corresponding isoclinic error was 0.75. Results from the manual and automated methods showed good agreement. It is concluded that automated photoelastic analysis based on phase-stepping procedures offers a potentially accurate and reliable tool for stress analysts.

  11. Standardized Full-Field Electroretinography in the Green Monkey (Chlorocebus sabaeus)

    DEFF Research Database (Denmark)

    Bouskila, Joseph; Javadi, Pasha; Palmour, Roberta M

    2014-01-01

    Full-field electroretinography is an objective measure of retinal function, serving as an important diagnostic clinical tool in ophthalmology for evaluating the integrity of the retina. Given the similarity between the anatomy and physiology of the human and Green Monkey eyes, this species has...... increasingly become a favorable non-human primate model for assessing ocular defects in humans. To test this model, we obtained full-field electroretinographic recordings (ERG) and normal values for standard responses required by the International Society for Clinical Electrophysiology of Vision (ISCEV...... in humans and other non-human primate species (Macaca mulatta and Macaca fascicularis). These results validate the Green Monkey as an excellent non-human primate model, with potential to serve for testing retinal function following various manipulations such as visual deprivation or drug evaluation....

  12. Screening for diabetic retinopathy using new mydriasis-free, full-field flicker ERG recording device

    Science.gov (United States)

    Fukuo, Motonobu; Kondo, Mineo; Hirose, Akira; Fukushima, Harumi; Ikesugi, Kengo; Sugimoto, Masahiko; Kato, Kumiko; Uchigata, Yasuko; Kitano, Shigehiko

    2016-01-01

    Diabetic retinopathy (DR) is a leading cause of blindness among working-age adults. Therefore, it is important to detect DR accurately during mass screening. The purpose of this study was to determine whether a small, hand-held, mydriasis-free, full-field flicker electroretinographic (ERGs) device called RETeval can be used to screen for DR. To accomplish this, we recorded full-field flicker ERGs with this device from 48 normal eyes and 118 eyes with different severities of DR in patients with diabetes mellitus (DM). This system delivered a constant flash retinal luminance by adjusting the flash luminance that compensated for changes in the pupil size. Our results showed that there were significant correlations between the severity of DR and the implicit times (P flicker ERGs recorded by the small, mydryasis-free ERG system can be used as an adjunctive tool to screen for DR. PMID:27824158

  13. Study of Wood Plastic Composites elastic behaviour using full field measurements

    Directory of Open Access Journals (Sweden)

    Graciaa A.

    2010-06-01

    Full Text Available In this study, the mechanical properties and microstructure of HDPE/wood fibre composites are investigated. The four-point bending and tensile behaviour of Wood Plastic Composite (WPC with or without additive are studied by using full-field strain measurements by 3-D Digital Image Correlation (3-D DIC. A non-linear behaviour is shown. The modulus of elasticity (MOE is calculated as the tangent at zero strain of a Maxwell-Bingham model fitted onto experimental data. Four-point bending tests are analyzed thanks to the spatial standard deviation of the longitudinal strain field to determine the degree of heterogeneity. Cyclic tensile tests have been performed in order to analyze the damage of the material. Moreover, Scanning Electron Microscope (SEM is used to characterize the morphology of the wood fibre/HDPE matrix interface for specimens with maleic anhydride modified polyethylene additive (MAPE.

  14. Damage assessment in a sandwich panel based on full-field vibration measurements

    Science.gov (United States)

    Seguel, F.; Meruane, V.

    2018-03-01

    Different studies have demonstrated that vibration characteristics are sensitive to debonding in composite structures. Nevertheless, one of the main restrictions of vibration measurements is the number of degrees of freedom that can be acquired simultaneously, which restricts the size of the damage that can be identified. Recent studies have shown that it is possible to use high-speed three-dimensional (3-D) digital image correlation (DIC) techniques for full-field vibration measurements. With this technique, it is possible to take measurements at thousands of points on the surface of a structure with a single snapshot. The present article investigates the application of full-field vibration measurements in the debonding assessment of an aluminium honeycomb sandwich panel. Experimental data from an aluminium honeycomb panel containing different damage scenarios is acquired by a high-speed 3-D DIC system; four methodologies to compute damage indices are evaluated: mode shape curvatures, uniform load surface, modal strain energy and gapped smoothing.

  15. Field size dependence of wedge factor: miniphantom vs full phantom measurements

    International Nuclear Information System (INIS)

    Allen Li, X.; Szanto, J.; Soubra, M.; Gerig, L. H.

    1995-01-01

    It is empirically known that the transmission factor for wedge in a high-energy photon beam is dependent upon field size and depth of measurement. The field-size dependence of wedge factors may be attributed to changes in (i) head scatter, (ii) phantom scatter, and (iii) backscatter from the wedge into the linac monitor chamber. In this work we present the results of studies designed to examine each of these factors in isolation. The wedge factors for wedges with nominal wedge angles of 15 deg. , 30 deg. , 45 deg. and 60 deg. were measured with a 3-g/cm 2 -diameter narrow cylindrical phantom (miniphantom), a brass cap with 1.5-g/cm 2 side-wall thickness and a full water phantom for 6-, 10- and 18-MV photon beams. The measurements were performed with and without flattening filter in place. The wedge factors measured with the miniphantom and the brass cap exclude the phantom scatter contribution. It has been found that the field-size behaviour of wedge factor measured with full water phantom is similar to that measured with the miniphantom and cap. This indicates that the head scatter radiation is the major contributor to the field size dependence of wedge factors. Wedge factors measured with water phantom are up to 5.0% smaller than those measured with miniphantom. This difference increases with wedge angle. When Measured with the flattening filter removed, the field size dependence of the wedge factor is reduced. This justify that the flattening filter is one of the major contributors to head scatters. The measurement results made with the brass cap agree well with those made by using the miniphantom. By measuring the monitor chamber output, it is found that the backscatters from the wedge into the linac ion chamber have little effect on the field size dependence of the wedge factor

  16. Identification of the electroelastic coupling from full multi-physical fields measured at the micrometre scale

    Energy Technology Data Exchange (ETDEWEB)

    Amiot, F [MIC-DTU, Oersted Plads, Bygning 345 Oe, Lyngby DK-2800 (Denmark); Hild, F [LMT Cachan, ENS de Cachan/CNRS-UMR 8535/Universite Paris 6, 61 Avenue du President Wilson, F-94235 Cachan Cedex (France); Kanoufi, F [Laboratoire de Chimie Analytique, ESPCI/CNRS-UMR 7121, 10 rue Vauquelin, Paris F-75005 (France); Roger, J P [Laboratoire d' Optique Physique, ESPCI/CNRS-UPR A0005 / Universite Paris 6, 10 rue Vauquelin, Paris F-75005 (France)

    2007-06-07

    Metal coated microcantilevers are used as transducers of their electrochemical environment. Using the metallic layer of these cantilevers as a working electrode allows one to modify the electrochemical state of the cantilever surface. Since the mechanical behaviour of micrometre scale objects is significantly surface-driven, this environment modification induces bending of the cantilever. Using a full-field interferometric measurement set-up to monitor the objects then provides an optical phase map, which is found to originate from both electrochemical and mechanical effects. The scaling of the electrochemically-induced phase with respect to the surface charge density is modelled according to Gouy-Chapman-Stern theory, whereas the relationship between the mechanical effect and the surface charge density is analysed. An identification technique is described to determine a modelling of the electroelastic coupling and to identify the spatial charge density distribution from full-field phase measurements. Minimizing the least-squares gap between the measured phase and a statically admissible phase field, the mechanical effect is found to be charge-driven. The charge density field is also found to be singular on the cantilever edge, and the shear stress versus charge density is found to be non-linear.

  17. Full-field transmission-type angle-deviation optical microscope with reflectivity-height transformation.

    Science.gov (United States)

    Chiu, Ming-Hung; Tan, Chen-Tai; Tsai, Ming-Hung; Yang, Ya-Hsin

    2015-10-01

    This full-field transmission-type three-dimensional (3D) optical microscope is constructed based on the angle deviation method (ADM) and the algorithm of reflectivity-height transformation (RHT). The surface height is proportional to the deviation angle of light passing through the object. The angle deviation and surface height can be measured based on the reflectivity closed to the critical angle using a parallelogram prism and two CCDs.

  18. Image processing of full-field strain data and its use in model updating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W; Mottershead, J E [Centre for Engineering Dynamics, School of Engineering, University of Liverpool, UK, L69 3GH (United Kingdom); Sebastian, C M; Patterson, E A, E-mail: wangweizhuo@gmail.com [Composite Vehicle Research Center, Michigan State University, Lansing, MI (United States)

    2011-07-19

    Finite element model updating is an inverse problem based on measured structural outputs, typically natural frequencies. Full-field responses such as static stress/strain patterns and vibration mode shapes contain valuable information for model updating but within large volumes of highly-redundant data. Pattern recognition and image processing provide feasible techniques to extract effective and efficient information, often known as shape features, from this data. For instance, the Zernike polynomials having the properties of orthogonality and rotational invariance are powerful decomposition kernels for a shape defined within a unit circle. In this paper, full field strain patterns for a specimen, in the form of a square plate with a circular hole, under a tensile load are considered. Effective shape features can be constructed by a set of modified Zernike polynomials. The modification includes the application of a weighting function to the Zernike polynomials so that high strain magnitudes around the hole are well represented. The Gram-Schmidt process is then used to ensure orthogonality for the obtained decomposition kernels over the domain of the specimen. The difference between full-field strain patterns measured by digital image correlation (DIC) and reconstructed using 15 shape features (Zernike moment descriptors, ZMDs) at different steps in the elasto-plastic deformation of the specimen is found to be very small. It is significant that only a very small number of shape features are necessary and sufficient to represent the full-field data. Model updating of nonlinear elasto-plastic material properties is carried out by adjusting the parameters of a FE model until the FE strain pattern converges upon the measured strains as determined using ZMDs.

  19. Halo suppression in full-field x-ray Zernike phase contrast microscopy.

    Science.gov (United States)

    Vartiainen, Ismo; Mokso, Rajmund; Stampanoni, Marco; David, Christian

    2014-03-15

    Visible light Zernike phase contrast (ZPC) microscopy is a well established method for imaging weakly absorbing samples. The method is also used with hard x-ray photon energies for structural evaluation of material science and biological applications. However, the method suffers from artifacts that are inherent for the Zernike image formation. In this Letter, we investigate their origin and experimentally show how to suppress them in x-ray full-field ZPC microscopy based on diffractive x-ray optics.

  20. Full-field measurement of dynamic stress by mechanoluminescence sensing film

    Science.gov (United States)

    Li, Chenshu; Xu, Chao-Nan; Imai, Yusuke; Bu, Nan

    2009-07-01

    Full-field measurement of dynamic stress has been realized by coating the surface of the test object metal with a upgrade mechanoluminescence sensing film of SrAl2O4:Eu (SAOE). Mechanoluminescent materials are attractive smart materials that can emit light induced by mechanical deformation. The ML sensing film of SAOE has been developed to make possible to visualize dynamic stress. Consequently this visualization technique has been become a promising experimental technique to investigate full-field stress analysis. In this paper we report the applications of the SAO ML sensing film for full-field stress analysis in aluminum alloy 5052 samples. Using the SAOE ML sensing film, the stress concentration produced by a circular hole was observed with the naked eyes in real time and the two-dimensional stress distribution was quantitatively measured; the complex and dynamic Portevin-Le Chatelier (PLC) effect, known as instability during plastic deformation, has been visualized, and the propagating characteristics of PLC bands were precisely investigated.

  1. Stress-induced birefringence control in femtosecond laser glass welding

    Science.gov (United States)

    Gstalter, M.; Chabrol, G.; Bahouka, A.; Serreau, L.; Heitz, J.-L.; Taupier, G.; Dorkenoo, K.-D.; Rehspringer, J.-L.; Lecler, S.

    2017-11-01

    Glass welding by femtosecond laser pulses causes microscopic structural modifications, affecting the refractive index due to residual stress. Locally induced birefringence is studied by photoelasticimetry using a polarized light microscope. The study is performed on borosilicate thin glass plates using an industrial femtosecond laser generating 300 fs pulses at 500 kHz, with a 100 mm focusing length F-theta lens allowing fast welding. For low-energy deposition, the principal birefringence axes are determined to be homogenous along the seam and perpendicular and parallel to the laser scanning direction. Tensile stress is induced in the laser scanning direction by the welding seams. The induced birefringence is determined to be equivalent for in-volume irradiated track and welding seams. An inhomogeneity of the birefringence within the seam is observed for the first time at high-energy deposition. The distribution of the birefringence can be controlled with the laser scanning patterns. The amount of residual stress is measured by compensating the local birefringence. The birefringence Δ n is estimated at 2.4 × 10^{-4}, corresponding to a residual stress amount around 59 MPa. The influence of the welding geometry is also illustrated.

  2. Exploring direct 3D interaction for full horizontal parallax light field displays using leap motion controller.

    Science.gov (United States)

    Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

    2015-04-14

    This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

  3. 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

  4. Time-on-pitch or full-game GPS analysis procedures for elite field hockey?

    Science.gov (United States)

    White, Andrew D; MacFarlane, Niall

    2013-09-01

    The current study assessed the impact of full-game (FG) and time-on-pitch (TOP) procedures for global-positioning-system (GPS) analysis on the commonly used markers of physical performance in elite field hockey. Sixteen international male field hockey players, age 19-30, were studied (yielding 73 player analyses over 8 games). Physical activity was recorded using a 5-Hz GPS. Distance covered, player load, maximum velocity, high-acceleration efforts, and distance covered at specified speed zones were all agreeable for both analysis procedures (P > .05). However, percentage time spent in 0-6 km/h was higher for FG (ES: -21% to -16%; P 6.39 m/s) and relative distance (m/min) were higher for TOP (ES: 8-10%, 2-7%, 2-3%, 1-1%, 0-1%, respectively; P GPS analysis procedures should be appropriate for the nature of the sport being studied. In field hockey, TOP and FG analysis procedures are comparable for distance-related variables but significantly different for time-dependent factors. Using inappropriate analysis procedures can alter the perceived physiological demand of elite field hockey because of "rolling" substitutions. Inaccurate perception of physiological demand could negatively influence training prescription (for both intensity and volume).

  5. Birefringence and residual stress induced by CO2 laser mitigation of damage growth in fused silica

    Science.gov (United States)

    Gallais, L.; Cormont, P.; Rullier, J. L.

    2009-10-01

    We investigate the residual stress field created near mitigated sites and its influence on the efficiency on the CO2 laser mitigation of damage growth process. A numerical model of CO2 laser interaction with fused silica is developed that take into account laser energy absorption, heat transfer, thermally-induced stress and birefringence. Specific photoelastic methods are developed to characterize the residual stress near mitigated sites in fused silica samples. The stress distribution and quantitative values of stress levels are obtained for sites treated with the CO2 laser in various conditions of energy deposition (beam size, pulse duration, incident power). The results obtained also show that the presence of birefringence/residual stress around the mitigated sites has a critical effect on their laser damage resistance.

  6. Study of Wood Plastic Composites elastic behaviour using full field measurements

    Science.gov (United States)

    Ben Mbarek, T.; Robert, L.; Hugot, F.; Orteu, J. J.; Sammouda, H.; Graciaa, A.; Charrier, B.

    2010-06-01

    In this study, the mechanical properties and microstructure of HDPE/wood fibre composites are investigated. The four-point bending and tensile behaviour of Wood Plastic Composite (WPC) with or without additive are studied by using full-field strain measurements by 3-D Digital Image Correlation (3-D DIC). A non-linear behaviour is shown. The modulus of elasticity (MOE) is calculated as the tangent at zero strain of a Maxwell-Bingham model fitted onto experimental data. Four-point bending tests are analyzed thanks to the spatial standard deviation of the longitudinal strain field to determine the degree of heterogeneity. Cyclic tensile tests have been performed in order to analyze the damage of the material. Moreover, Scanning Electron Microscope (SEM) is used to characterize the morphology of the wood fibre/HDPE matrix interface for specimens with maleic anhydride modified polyethylene additive (MAPE).

  7. Full-field parallel interferometry coherence probe microscope for high-speed optical metrology.

    Science.gov (United States)

    Safrani, A; Abdulhalim, I

    2015-06-01

    Parallel detection of several achromatic phase-shifted images is used to obtain a high-speed, high-resolution, full-field, optical coherence probe tomography system based on polarization interferometry. The high enface imaging speed, short coherence gate, and high lateral resolution provided by the system are exploited to determine microbump height uniformity in an integrated semiconductor chip at 50 frames per second. The technique is demonstrated using the Linnik microscope, although it can be implemented on any polarization-based interference microscopy system.

  8. Full-field optical coherence tomography using immersion Mirau interference microscope.

    Science.gov (United States)

    Lu, Sheng-Hua; Chang, Chia-Jung; Kao, Ching-Fen

    2013-06-20

    In this study, an immersion Mirau interference microscope was developed for full-field optical coherence tomography (FFOCT). Both the reference and measuring arms of the Mirau interferometer were filled with water to prevent the problems associated with imaging a sample in air with conventional FFOCT systems. The almost-common path interferometer makes the tomographic system less sensitive to environmental disturbances. En face OCT images at various depths were obtained with phase-shifting interferometry and Hariharan algorithm. This immersion interferometric method improves depth and quality in three-dimensional OCT imaging of scattering tissue.

  9. Polarisation dynamics of a birefringent Fabry-Perot cavity

    Science.gov (United States)

    Ejlli, A.; Della Valle, F.; Zavattini, G.

    2018-02-01

    Optical Fabry-Perot cavities always show a non-degeneracy of two orthogonal polarisation states. This is due to the unavoidable birefringence of dielectric mirrors whose effects are extremely important in Fabry-Perot-based high-accuracy polarimeters: in birefringent cavities, ellipticities and rotations mix. We have developed and present here a theory of the polarisation state dynamics in a birefringent Fabry-Perot resonator, and we validate it through measurements performed with the polarimeter of the PVLAS experiment. The measurements are performed while a laser is frequency-locked to the cavity, and provide values for the phase difference between the two orthogonal polarisation components introduced by the combination of the two cavity mirrors (equivalent wave-plate) and for the finesse of the cavity. The theoretical formulas and the experimental data agree well showing that the consequences of the mirror birefringence must be taken into account in this and in any other similar experiment.

  10. 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...

  11. Birefringent Microlens Array for Ultra High Resolution HMDs Project

    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...

  12. High-Bandwidth Dynamic Full-Field Profilometry for Nano-Scale Characterization of MEMS

    International Nuclear Information System (INIS)

    Chen, L-C; Huang, Y-T; Chang, P-B

    2006-01-01

    The article describes an innovative optical interferometric methodology to delivery dynamic surface profilometry with a measurement bandwidth up to 10MHz or higher and a vertical resolution up to 1 nm. Previous work using stroboscopic microscopic interferometry for dynamic characterization of micro (opto)electromechanical systems (M(O)EMS) has been limited in measurement bandwidth mainly within a couple of MHz. For high resonant mode analysis, the stroboscopic light pulse is insufficiently short to capture the moving fringes from dynamic motion of the detected structure. In view of this need, a microscopic prototype based on white-light stroboscopic interferometry with an innovative light superposition strategy was developed to achieve dynamic full-field profilometry with a high measurement bandwidth up to 10MHz or higher. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterisation of dynamic behaviours of the device. The full-field seventh-mode vibration at a vibratory frequency of 3.7MHz can be fully characterized and nano-scale vertical measurement resolution as well as tens micrometers of vertical measurement range can be performed

  13. Full-field stress determination in photoelasticity with phase shifting technique

    Science.gov (United States)

    Guo, Enhai; Liu, Yonggang; Han, Yongsheng; Arola, Dwayne; Zhang, Dongsheng

    2018-04-01

    Photoelasticity is an effective method for evaluating the stress and its spatial variations within a stressed body. In the present study, a method to determine the stress distribution by means of phase shifting and a modified shear-difference is proposed. First, the orientation of the first principal stress and the retardation between the principal stresses are determined in the full-field through phase shifting. Then, through bicubic interpolation and derivation of a modified shear-difference method, the internal stress is calculated from the point with a free boundary along its normal direction. A method to reduce integration error in the shear difference scheme is proposed and compared to the existing methods; the integration error is reduced when using theoretical photoelastic parameters to calculate the stress component with the same points. Results show that when the value of Δx/Δy approaches one, the error is minimum, and although the interpolation error is inevitable, it has limited influence on the accuracy of the result. Finally, examples are presented for determining the stresses in a circular plate and ring subjected to diametric loading. Results show that the proposed approach provides a complete solution for determining the full-field stresses in photoelastic models.

  14. 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.

  15. Dose reduction through gridless technique in digital full-field mammography

    International Nuclear Information System (INIS)

    Diekmann, F.; Diekmann, S.; Berzeg, S.; Blick, U.; Fischer, T.; Hamm, B.

    2003-01-01

    Purpose: To determine the role of the scatter grid in digital full-field mammography with respect to image quality and dose and to compare the experimental results with initial clinical experience. Materials and Methods: A phantom consisting of 205 fields that enclose gold dots of different thickness and size (CD-Mam phantom, Medical Department, Nijmegen, Netherlands) was used for digital full-field mammography with the conventional grid module and a special gridless module. Four different breast thicknesses were simulated using Plexiglas as scatter material. First, the phantom was exposed at the parameter and dose settings automatically selected in each experimental setup (with and without grid). Subsequently, the phantom was exposed at the different simulated breast thicknesses using the gridless module in combination with the parameters automatically selected for the grid module. This was followed by a series of phantom mammograms obtained with the experimental setup reversed. The 16 mammograms were evaluated by 3 readers and the results compared considering breast thickness, radiation dose, and quality. The gridless module was used for preoperative labeling in 16 patients for comparison of mammograms obtained with and without a grid. Results: For the same entrance dose used in routine mammography, digital mammography without grid is superior to digital mammography with grid when performed on simulated thin breasts (Plexiglas less than 3 cm), with no difference found when performed on simulated large breasts. The advantages of gridless mammography are more pronounced at a markedly reduced entrance dose (identical parenchymal dose without and with grid using the dose automatically selected for the gridless module). This tendency is confirmed by the initial clinical comparison. (orig.) [de

  16. Magnetic imaging with full-field soft X-ray microscopies

    International Nuclear Information System (INIS)

    Fischer, Peter; Im, Mi-Young; Baldasseroni, Chloe; Bordel, Catherine; Hellman, Frances; Lee, Jong-Soo; Fadley, Charles S.

    2013-01-01

    Progress toward a fundamental understanding of magnetism continues to be of great scientific interest and high technological relevance. To control magnetization on the nanoscale, external magnetic fields and spin polarized currents are commonly used. In addition, novel concepts based on spin manipulation by electric fields or photons are emerging which benefit from advances in tailoring complex magnetic materials. Although the nanoscale is at the very origin of magnetic behavior, there is a new trend toward investigating mesoscale magnetic phenomena, thus adding complexity and functionality, both of which will become crucial for future magnetic devices. Advanced analytical tools are thus needed for the characterization of magnetic properties spanning the nano- to the meso-scale. Imaging magnetic structures with high spatial and temporal resolution over a large field of view and in three dimensions is therefore a key challenge. A variety of spectromicroscopic techniques address this challenge by taking advantage of variable-polarization soft X-rays, thus enabling X-ray dichroism effects provide magnetic contrast. These techniques are also capable of quantifying in an element-, valence- and site-sensitive way the basic properties of ferro(i)- and antiferro-magnetic systems, such as spin and orbital moments, spin configurations from the nano- to the meso-scale and spin dynamics with sub-ns time resolution. This paper reviews current achievements and outlines future trends with one of these spectromicroscopies, magnetic full field transmission soft X-ray microscopy (MTXM) using a few selected examples of recent research on nano- and meso-scale magnetic phenomena. The complementarity of MTXM to X-ray photoemission electron microscopy (X-PEEM) is also emphasized

  17. Magnetic imaging with full-field soft X-ray microscopies

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Peter, E-mail: PJFischer@lbl.gov [Center for X-ray Optics, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Im, Mi-Young [Center for X-ray Optics, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Baldasseroni, Chloe [Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720 (United States); Bordel, Catherine; Hellman, Frances [Department of Physics, University of California Berkeley, Berkeley, CA 94720 (United States); Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94270 (United States); Lee, Jong-Soo [Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873 (Korea, Republic of); Fadley, Charles S. [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94270 (United States)

    2013-08-15

    Progress toward a fundamental understanding of magnetism continues to be of great scientific interest and high technological relevance. To control magnetization on the nanoscale, external magnetic fields and spin polarized currents are commonly used. In addition, novel concepts based on spin manipulation by electric fields or photons are emerging which benefit from advances in tailoring complex magnetic materials. Although the nanoscale is at the very origin of magnetic behavior, there is a new trend toward investigating mesoscale magnetic phenomena, thus adding complexity and functionality, both of which will become crucial for future magnetic devices. Advanced analytical tools are thus needed for the characterization of magnetic properties spanning the nano- to the meso-scale. Imaging magnetic structures with high spatial and temporal resolution over a large field of view and in three dimensions is therefore a key challenge. A variety of spectromicroscopic techniques address this challenge by taking advantage of variable-polarization soft X-rays, thus enabling X-ray dichroism effects provide magnetic contrast. These techniques are also capable of quantifying in an element-, valence- and site-sensitive way the basic properties of ferro(i)- and antiferro-magnetic systems, such as spin and orbital moments, spin configurations from the nano- to the meso-scale and spin dynamics with sub-ns time resolution. This paper reviews current achievements and outlines future trends with one of these spectromicroscopies, magnetic full field transmission soft X-ray microscopy (MTXM) using a few selected examples of recent research on nano- and meso-scale magnetic phenomena. The complementarity of MTXM to X-ray photoemission electron microscopy (X-PEEM) is also emphasized.

  18. Implementation and Evaluation of the Virtual Fields Method: Determining Constitutive Model Parameters From Full-Field Deformation Data.

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Sharlotte Lorraine Bolyard; Scherzinger, William M.

    2014-09-01

    The Virtual Fields Method (VFM) is an inverse method for constitutive model parameter identication that relies on full-eld experimental measurements of displacements. VFM is an alternative to standard approaches that require several experiments of simple geometries to calibrate a constitutive model. VFM is one of several techniques that use full-eld exper- imental data, including Finite Element Method Updating (FEMU) techniques, but VFM is computationally fast, not requiring iterative FEM analyses. This report describes the im- plementation and evaluation of VFM primarily for nite-deformation plasticity constitutive models. VFM was successfully implemented in MATLAB and evaluated using simulated FEM data that included representative experimental noise found in the Digital Image Cor- relation (DIC) optical technique that provides full-eld displacement measurements. VFM was able to identify constitutive model parameters for the BCJ plasticity model even in the presence of simulated DIC noise, demonstrating VFM as a viable alternative inverse method. Further research is required before VFM can be adopted as a standard method for constitu- tive model parameter identication, but this study is a foundation for ongoing research at Sandia for improving constitutive model calibration.

  19. Applying a Bayesian Approach to Identification of Orthotropic Elastic Constants from Full Field Displacement Measurements

    Directory of Open Access Journals (Sweden)

    Le Riche R.

    2010-06-01

    Full Text Available A major challenge in the identification of material properties is handling different sources of uncertainty in the experiment and the modelling of the experiment for estimating the resulting uncertainty in the identified properties. Numerous improvements in identification methods have provided increasingly accurate estimates of various material properties. However, characterizing the uncertainty in the identified properties is still relatively crude. Different material properties obtained from a single test are not obtained with the same confidence. Typically the highest uncertainty is associated with respect to properties to which the experiment is the most insensitive. In addition, the uncertainty in different properties can be strongly correlated, so that obtaining only variance estimates may be misleading. A possible approach for handling the different sources of uncertainty and estimating the uncertainty in the identified properties is the Bayesian method. This method was introduced in the late 1970s in the context of identification [1] and has been applied since to different problems, notably identification of elastic constants from plate vibration experiments [2]-[4]. The applications of the method to these classical pointwise tests involved only a small number of measurements (typically ten natural frequencies in the previously cited vibration test which facilitated the application of the Bayesian approach. For identifying elastic constants, full field strain or displacement measurements provide a high number of measured quantities (one measurement per image pixel and hence a promise of smaller uncertainties in the properties. However, the high number of measurements represents also a major computational challenge in applying the Bayesian approach to full field measurements. To address this challenge we propose an approach based on the proper orthogonal decomposition (POD of the full fields in order to drastically reduce their

  20. 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.

  1. 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.

  2. Broad frequency band full field measurements for advanced applications: Point-wise comparisons between optical technologies

    Science.gov (United States)

    Zanarini, Alessandro

    2018-01-01

    The progress of optical systems gives nowadays at disposal on lightweight structures complex dynamic measurements and modal tests, each with its own advantages, drawbacks and preferred usage domains. It is thus more easy than before to obtain highly spatially defined vibration patterns for many applications in vibration engineering, testing and general product development. The potential of three completely different technologies is here benchmarked on a common test rig and advanced applications. SLDV, dynamic ESPI and hi-speed DIC are here first deployed in a complex and unique test on the estimation of FRFs with high spatial accuracy from a thin vibrating plate. The latter exhibits a broad band dynamics and high modal density in the common frequency domain where the techniques can find an operative intersection. A peculiar point-wise comparison is here addressed by means of discrete geometry transforms to put all the three technologies on trial at each physical point of the surface. Full field measurement technologies cannot estimate only displacement fields on a refined grid, but can exploit the spatial consistency of the results through neighbouring locations by means of numerical differentiation operators in the spatial domain to obtain rotational degrees of freedom and superficial dynamic strain distributions, with enhanced quality, compared to other technologies in literature. Approaching the task with the aid of superior quality receptance maps from the three different full field gears, this work calculates and compares rotational and dynamic strain FRFs. Dynamic stress FRFs can be modelled directly from the latter, by means of a constitutive model, avoiding the costly and time-consuming steps of building and tuning a numerical dynamic model of a flexible component or a structure in real life conditions. Once dynamic stress FRFs are obtained, spectral fatigue approaches can try to predict the life of a component in many excitation conditions. Different

  3. 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.)

  4. 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.)

  5. Use of Iodine-based contrast media in digital full-field mammography - initial experience

    International Nuclear Information System (INIS)

    Diekmann, F.; Diekmann, S.; Taupitz, M.; Bick, U.; Winzer, K.-J.; Huettner, C.; Muller, S.; Jeunehomme, F.; Hamm, B.

    2003-01-01

    Aim: To investigate the use of iodine-based contrast media in digital full-field mammography. Methods: After performing initial phantom studies, seven patients underwent digital mammography (Senographe 2000D, GE Medical Systems, Milwaukee, USA) using a specially filtered beam before as well as 60, 120, and 180 seconds after injection of 80 ml of iodine contrast medium (Ultravist 370, Schering AG, Germany). The precontrast mammograms were then subtracted from the postcontrast mammograms and the resulting images compared with a contrast-enhanced dynamic MRI study, performed on all women. Results: Contrast medium accumulation within the tumors was visualized with a good quality in all cases. The conditions under which successful contrast-enhanced digital mammography can be performed were determined in phantom studies. Conclusions: Contrast-enhanced digital mammography has a potential for improving the visualization of breast tumors in mammography using special beam filtering, adjusted X-ray parameters, proper timing, and suitable subtraction software. (orig.) [de

  6. Full-field implementation of a perfect eavesdropper on a quantum cryptography system.

    Science.gov (United States)

    Gerhardt, Ilja; Liu, Qin; Lamas-Linares, Antía; Skaar, Johannes; Kurtsiefer, Christian; Makarov, Vadim

    2011-06-14

    Quantum key distribution (QKD) allows two remote parties to grow a shared secret key. Its security is founded on the principles of quantum mechanics, but in reality it significantly relies on the physical implementation. Technological imperfections of QKD systems have been previously explored, but no attack on an established QKD connection has been realized so far. Here we show the first full-field implementation of a complete attack on a running QKD connection. An installed eavesdropper obtains the entire 'secret' key, while none of the parameters monitored by the legitimate parties indicate a security breach. This confirms that non-idealities in physical implementations of QKD can be fully practically exploitable, and must be given increased scrutiny if quantum cryptography is to become highly secure.

  7. 3D elastic-orthorhombic anisotropic full-waveform inversion: Application to field OBC data

    KAUST Repository

    Oh, Juwon

    2016-09-06

    For the purpose of extracting higher resolution information from a 3D field data set, we apply a 3D elastic orthorhombic (ORT) anisotropic full waveform inversion (FWI) to hopefully better represent the physics of the Earth. We utilize what we consider as the optimal parameterization for surface acquired seismic data over a potentially orthorhombic media. This parameterization admits the possibility of incorporating a hierarchical implementation moving from higher anisotropy symmetry to lower ones. From the analysis of the radiation pattern of this new parameterization, we focus the inversion of the 3D data on the parameters that may have imprint on the data with minimal tradeoff, and as a result we invert for the horizontal P-wave velocity model, an ε1 model, its orthorhombic deviation, and the shear wave velocity. The inverted higher resolution models provide reasonable insights of the medium.

  8. Full-Scale Field Test of a Blade-Integrated Dual-Telescope Wind Lidar

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Sjöholm, Mikael; Angelou, Nikolas

    Introduction In recent years the use of wind lidars mounted directly on wind turbines has received increasing attention, and such systems are becoming commercially available. One aim of turbine-mounted wind lidars is to use them for prevision in connection with advanced feed-forward control systems...... for load reduction and power optimization. To date, main attention has been on control schemes where measurements of wind speeds and direction upwind are used for yaw and speed corrections. In this study we investigate experimentally the feasibility of using lidars integrated in the turbine blades...... in the top and bottom of the rotor plane. Conclusion We present here what we believe is the first successful wind speed measurements from a dual-telescope lidar installed on the blade of an operating wind turbine. The full-scale field test performed in the summer of 2012 has clearly demonstrated...

  9. Evaluation of mean glandular dose in a full-field digital mammography unit in Tabriz (IR)

    International Nuclear Information System (INIS)

    Riabi, H. A.; Mehnati, P.; Mesbahi, A.

    2010-01-01

    This study was aimed at evaluating the mean glandular dose (MGD) and affecting factors during mammography examinations by a full-field digital mammography unit. An extensive quality control program was performed to assure that the unit is properly working. Required information including compressed breast thickness (CBT), breast parenchymal pattern and technical factors used for imaging were recorded. An entrance skin exposure measurement was also performed using slabs of polymethylmethacrylate with 2-8 cm thickness. On the basis of recorded information and measured data, the MGD was estimated for 1145 mammography examinations obtained from 298 patients. Mean CBTs of 4.9 and 5.8 cm and MGDs of 2 and 2.4 mGy were observed for cranio-caudal and medio-lateral oblique views, respectively. Significant correlation was seen between MGD and CBT, breast parenchymal pattern and applied kVp and mAs. (authors)

  10. Tissue imaging using full field optical coherence microscopy with short multimode fiber probe

    Science.gov (United States)

    Sato, Manabu; Eto, Kai; Goto, Tetsuhiro; Kurotani, Reiko; Abe, Hiroyuki; Nishidate, Izumi

    2018-03-01

    In achieving minimally invasive accessibility to deeply located regions the size of the imaging probes is important. We demonstrated full-field optical coherence tomography (FF-OCM) using an ultrathin forward-imaging short multimode fiber (SMMF) probe of 50 μm core diameter, 125 μm diameter, and 7.4 mm length for optical communications. The axial resolution was measured to be 2.14 μm and the lateral resolution was also evaluated to be below 4.38 μm using a test pattern (TP). The spatial mode and polarization characteristics of SMMF were evaluated. Inserting SMMF to in vivo rat brain, 3D images were measured and 2D information of nerve fibers was obtained. The feasibility of an SMMF as an ultrathin forward-imaging probe in FF-OCM has been demonstrated.

  11. High efficiency for prostate biopsy qualification with full-field OCT after training

    Science.gov (United States)

    Yang, C.; Ricco, R.; Sisk, A.; Duc, A.; Sibony, M.; Beuvon, F.; Dalimier, E.; Delongchamps, N. B.

    2016-02-01

    Full-field optical coherence tomography (FFOCT) offers a fast and non-destructive method of obtaining images of biological tissues at ultrahigh resolution, approaching traditional histological sections. In the context of prostate cancer diagnosis involving multiple biopsies, FFOCT could be used to validate the cores just after they are obtained in order to guide the number of biopsies to be performed. The aim of the study was to define and test a training protocol for efficient FFOCT prostate biopsy assessment. Three readers (a pathologist with previous experience with FFOCT, a pathologist new to FFOCT, and a urologist new to FFOCT) were trained to read FFOCT images of prostate biopsies on a set of 20 commented zooms (1 mm field of view) and 25 complete images. They were later tested on a set of 115 anonymized and randomized images of prostate biopsies. The results showed that an extra 30 images were necessary for more complete training as compared to prior studies. After training, pathologists obtained 100% sensitivity on high-grade cancer detection and 96% overall specificity; the urologist obtained 88% sensitivity on high-grade cancer and 89% overall specificity. Overall, the readers obtained a mean of 93% accuracy of qualifying malignancy on prostate biopsies. Moreover, the two pathologists showed a steeper learning curve than the urologist. This study demonstrates that a training protocol for such a new imaging modality may be implemented and yield very high efficiency for the pre-histologic detection of malignancy on prostate biopsies.

  12. A novel full-field experimental method to measure the local compressibility of gas diffusion media

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Yeh-Hung; Li, Yongqiang [Electrochemical Energy Research Lab, GM R and D, Honeoye Falls, NY 14472 (United States); Rock, Jeffrey A. [GM Powertrain, Honeoye Falls, NY 14472 (United States)

    2010-05-15

    The gas diffusion medium (GDM) in a proton exchange membrane (PEM) fuel cell needs to simultaneously satisfy the requirements of transporting reactant gases, removing product water, conducting electrons and heat, and providing mechanical support to the membrane electrode assembly (MEA). Concerning the localized over-compression which may force carbon fibers and other conductive debris into the membrane to cause fuel cell failure by electronically shorting through the membrane, we have developed a novel full-field experimental method to measure the local thickness and compressibility of GDM. Applying a uniform air pressure upon a thin polyimide film bonded on the top surface of the GDM with support from the bottom by a flat metal substrate and measuring the thickness change using the 3-D digital image correlation technique with an out-of-plane displacement resolution less than 0.5 {mu}m, we have determined the local thickness and compressive stress/strain behavior in the GDM. Using the local thickness and compressibility data over an area of 11.2 mm x 11.2 mm, we numerically construct the nominal compressive response of a commercial Toray trademark TGP-H-060 based GDM subjected to compression by flat platens. Good agreement in the nominal stress/strain curves from the numerical construction and direct experimental flat-platen measurement confirms the validity of the methodology proposed in this article. The result shows that a nominal pressure of 1.4 MPa compressed between two flat platens can introduce localized compressive stress concentration of more than 3 MPa in up to 1% of the total area at various locations from several hundred micrometers to 1 mm in diameter. We believe that this full-field experimental method can be useful in GDM material and process development to reduce the local hard spots and help to mitigate the membrane shorting failure in PEM fuel cells. (author)

  13. Full field reservoir modeling of shale assets using advanced data-driven analytics

    Directory of Open Access Journals (Sweden)

    Soodabeh Esmaili

    2016-01-01

    Full Text Available Hydrocarbon production from shale has attracted much attention in the recent years. When applied to this prolific and hydrocarbon rich resource plays, our understanding of the complexities of the flow mechanism (sorption process and flow behavior in complex fracture systems - induced or natural leaves much to be desired. In this paper, we present and discuss a novel approach to modeling, history matching of hydrocarbon production from a Marcellus shale asset in southwestern Pennsylvania using advanced data mining, pattern recognition and machine learning technologies. In this new approach instead of imposing our understanding of the flow mechanism, the impact of multi-stage hydraulic fractures, and the production process on the reservoir model, we allow the production history, well log, completion and hydraulic fracturing data to guide our model and determine its behavior. The uniqueness of this technology is that it incorporates the so-called “hard data” directly into the reservoir model, so that the model can be used to optimize the hydraulic fracture process. The “hard data” refers to field measurements during the hydraulic fracturing process such as fluid and proppant type and amount, injection pressure and rate as well as proppant concentration. This novel approach contrasts with the current industry focus on the use of “soft data” (non-measured, interpretive data such as frac length, width, height and conductivity in the reservoir models. The study focuses on a Marcellus shale asset that includes 135 wells with multiple pads, different landing targets, well length and reservoir properties. The full field history matching process was successfully completed using this data driven approach thus capturing the production behavior with acceptable accuracy for individual wells and for the entire asset.

  14. A novel full-field experimental method to measure the local compressibility of gas diffusion media

    Science.gov (United States)

    Lai, Yeh-Hung; Li, Yongqiang; Rock, Jeffrey A.

    The gas diffusion medium (GDM) in a proton exchange membrane (PEM) fuel cell needs to simultaneously satisfy the requirements of transporting reactant gases, removing product water, conducting electrons and heat, and providing mechanical support to the membrane electrode assembly (MEA). Concerning the localized over-compression which may force carbon fibers and other conductive debris into the membrane to cause fuel cell failure by electronically shorting through the membrane, we have developed a novel full-field experimental method to measure the local thickness and compressibility of GDM. Applying a uniform air pressure upon a thin polyimide film bonded on the top surface of the GDM with support from the bottom by a flat metal substrate and measuring the thickness change using the 3-D digital image correlation technique with an out-of-plane displacement resolution less than 0.5 μm, we have determined the local thickness and compressive stress/strain behavior in the GDM. Using the local thickness and compressibility data over an area of 11.2 mm × 11.2 mm, we numerically construct the nominal compressive response of a commercial Toray™ TGP-H-060 based GDM subjected to compression by flat platens. Good agreement in the nominal stress/strain curves from the numerical construction and direct experimental flat-platen measurement confirms the validity of the methodology proposed in this article. The result shows that a nominal pressure of 1.4 MPa compressed between two flat platens can introduce localized compressive stress concentration of more than 3 MPa in up to 1% of the total area at various locations from several hundred micrometers to 1 mm in diameter. We believe that this full-field experimental method can be useful in GDM material and process development to reduce the local hard spots and help to mitigate the membrane shorting failure in PEM fuel cells.

  15. [Imaging Blood Flow and Pulsation of Retinal Vessels with Full-Field Swept-Source OCT].

    Science.gov (United States)

    Spahr, H; Hillmann, D; Hain, C; Pfäffle, C; Sudkamp, H; Franke, G; Koch, P; Hüttmann, G

    2016-12-01

    Optical coherence tomography (OCT) uses interference to image the retina with high axial resolution. In the last 25 years, new technologies have permitted a steady increase in imaging speed, which made it possible to enlarge the imaged field and to avoid motion artefacts. The speed and precision of retinal imaging is now limited by photodamage of the retina caused by the focused OCT beam and by the speed of the scanning mechanics. Full-field swept-source (FF-SS)-OCT decreases irradiance on the retina and dispenses moving parts by using a camera to acquire the full volume of the retina in parallel. Here we show that FF-SS-OCT is rapid and precise enough to image pulsation in the retina induced by the heart beat. Series of OCT volumes 1.8 × 0.7 mm wide and 1.8 mm deep were recorded in young volunteers over a few cycles of the heart beat. Morphology of the retinal vessels, blood flow and tissue motion as caused by vessel pulsation were calculated from the OCT data. FF-SS-OCT was able to visualise the main structures of the neuronal retina, including vessels and small capillaries and without any motion artefacts. Information on three different dynamic processes was obtained from only one recorded series of OCT volumes: pulsation of blood flow and blood pressure in retinal vessels as well as pulsation of the choroid. Delays between arterial and venous pulse and delay between pulsation in retinal and choroidal vessels were calculated. With a time resolution of 0.5 ms, FF-SS-OCT is able to visualise previously unmeasurably fast changes in the retina, including the propagation of pulse waves. Georg Thieme Verlag KG Stuttgart · New York.

  16. Comparing seven candidate mission configurations for temporal gravity field retrieval through full-scale numerical simulation

    Science.gov (United States)

    Elsaka, Basem; Raimondo, Jean-Claude; Brieden, Phillip; Reubelt, Tilo; Kusche, Jürgen; Flechtner, Frank; Iran Pour, Siavash; Sneeuw, Nico; Müller, Jürgen

    2014-01-01

    The goal of this contribution is to focus on improving the quality of gravity field models in the form of spherical harmonic representation via alternative configuration scenarios applied in future gravimetric satellite missions. We performed full-scale simulations of various mission scenarios within the frame work of the German joint research project "Concepts for future gravity field satellite missions" as part of the Geotechnologies Program, funded by the German Federal Ministry of Education and Research and the German Research Foundation. In contrast to most previous simulation studies including our own previous work, we extended the simulated time span from one to three consecutive months to improve the robustness of the assessed performance. New is that we performed simulations for seven dedicated satellite configurations in addition to the GRACE scenario, serving as a reference baseline. These scenarios include a "GRACE Follow-on" mission (with some modifications to the currently implemented GRACE-FO mission), and an in-line "Bender" mission, in addition to five mission scenarios that include additional cross-track and radial information. Our results clearly confirm the benefit of radial and cross-track measurement information compared to the GRACE along-track observable: the gravity fields recovered from the related alternative mission scenarios are superior in terms of error level and error isotropy. In fact, one of our main findings is that although the noise levels achievable with the particular configurations do vary between the simulated months, their order of performance remains the same. Our findings show also that the advanced pendulums provide the best performance of the investigated single formations, however an accuracy reduced by about 2-4 times in the important long-wavelength part of the spectrum (for spherical harmonic degrees ), compared to the Bender mission, can be observed. Concerning state-of-the-art mission constraints, in particular

  17. Full-field assessment of wind turbine near-wake deviation in relation to yaw misalignment

    Directory of Open Access Journals (Sweden)

    J. J. Trujillo

    2016-04-01

    Full Text Available Presently there is a lack of data revealing the behaviour of the path followed by the near wake of full scale wind turbines and its dependence on yaw misalignment. Here we present an experimental analysis of the horizontal wake deviation of a 5 MW offshore wind turbine between 0.6 and 1.4 diameters downstream. The wake field has been scanned with a short-range lidar and the wake path has been reconstructed by means of two-dimensional Gaussian tracking. We analysed the measurements for rotor yaw misalignments arising in normal operation and during partial load, representing high thrust coefficient conditions. We classified distinctive wake paths with reference to yaw misalignment, based on the nacelle wind vane, in steps of 3° in a range of ±10.5°. All paths observed in the nacelle frame of reference showed a consistent convergence towards 0.9 rotor diameters downstream, suggesting a kind of wake deviation shift. This contrasts with published results from wind tunnels which in general report a convergence towards the rotor. The discrepancy is evidenced in particular in a comparison which we performed against published paths obtained by means of tip vortex tracking.

  18. Full-field characterization of thermal diffusivity in continuous-fiber ceramic composite materials and components

    Science.gov (United States)

    Steckenrider, J. Scott; Ellingson, William A.; Rothermel, Scott A.

    1995-03-01

    Continuous-fiber ceramic matrix composites (CFCCs) are currently being developed for various high-temperature applications, including use in advanced heat engines. Among the material classes of interest for such applications are silicon carbide (SiC)-fiber-reinforced SiC (SiC(f)/SiC), SiC-fiber-reinforced silicon nitride (SiC(f)/Si3N4), aluminum oxide (Al2O3)-fiber-reinforced Al2O3 (Al2O3(f)/Al2O3), and others. In such composites, the condition of the interfaces (between the fibers and matrix) are critical to the mechanical and thermal behavior of the component (as are conventional mechanical defects such as cracks, porosity, etc.). For example, oxidation of this interface (especially on carbon coated fibers) can seriously degrade both mechanical and thermal properties. Furthermore, thermal shock damage can degrade the matrix through extensive crack generation. A nondestructive evaluation method that could be used to assess interface condition, thermal shock damage, and to detect other `defects' would thus be very beneficial, especially if applicable to full-scale components. One method under development uses infrared thermal imaging to provide `single-shot' full-field assessment of the distribution of thermal properties in large components by measuring thermal diffusivity. By applying digital image filtering, interpolation, and least-squares-estimation techniques for noise reduction, we can achieve acquisition and analysis times of minutes or less with submillimeter spatial resolution. The system developed at Argonne National Laboratory has been used to examine the effects of thermal shock, oxidation treatment, density variations, and variations in oxidation resistance coatings in a full array of test specimens. Subscale CFCC components with nonplanar geometries have also been studied for manufacturing-induced variations in thermal properties.

  19. An Optimal Cure Process to Minimize Residual Void and Optical Birefringence for a LED Silicone Encapsulant

    Directory of Open Access Journals (Sweden)

    Min-Jae Song

    2014-05-01

    Full Text Available Silicone resin has recently attracted great attention as a high-power Light Emitting Diode (LED encapsulant material due to its good thermal stability and optical properties. In general, the abrupt curing reaction of the silicone resin for the LED encapsulant during the curing process induces reduction in the mechanical and optical properties of the LED product due to the generation of residual void and moisture, birefringence, and residual stress in the final formation. In order to prevent such an abrupt curing reaction, the reduction of residual void and birefringence of the silicone resin was observed through experimentation by introducing the multi-step cure processes, while the residual stress was calculated by conducting finite element analysis that coupled the heat of cure reaction and cure shrinkage. The results of experiment and analysis showed that it was during the three-step curing process that the residual void, birefringence, and residual stress reduced the most in similar tendency. Through such experimentation and finite element analysis, the study was able to confirm that the optimization of the LED encapsulant packaging process was possible.

  20. Birefringent phase demodulator: application to wave plate characterization.

    Science.gov (United States)

    Veiras, F E; Riobó, L M; Matteo, C L; Perez, L I; Garea, M T

    2015-03-20

    The scope of this work is to present a phase demodulator that enables the recovery of temporal phase information contained in the phase difference between two signals with different polarizations. This demodulator is a polarization interferometer that may consist only of a uniaxial crystal slab and a polarizer sheet. The phase shift between two orthogonal components of the electric field is translated into space by means of birefringent crystals, which act as demodulators or phase analyzers with great robustness. The experimental scheme utilized is based on a simple conoscopic interference setup. Each portion of the space in which the interference pattern is projected contains not only the unknown temporal phase we want to recover, but also a phase shift due to the uniaxial crystal itself. The underlying idea is developing simultaneous phase shifting with uniaxial crystals. Thus, different phase recovery techniques can be applied in order to maximize their ability to track high-speed signals. Depending on the characteristics of the fringe pattern, it will permit phase recovery via different classical procedures. In order to prove the demodulator under different experimental and signal processing schemes, we employed it for wave plate characterization. The results obtained not only allow some wave plate features such as axes determination and retardance to be characterized, but also prove the working principle and capabilities of the demodulator.

  1. Full Scale Field Trial of the Low Temperature Mercury Capture Process

    Energy Technology Data Exchange (ETDEWEB)

    Locke, James [CONSOL Energy Inc., South Park, PA (United States); Winschel, Richard [CONSOL Energy Inc., South Park, PA (United States)

    2012-05-21

    CONSOL Energy Inc., with partial funding from the Department of Energy (DOE) National Energy Technology Laboratory, designed a full-scale installation for a field trial of the Low-Temperature Mercury Control (LTMC) process, which has the ability to reduce mercury emissions from coal-fired power plants by over 90 percent, by cooling flue gas temperatures to approximately 230°F and absorbing the mercury on the native carbon in the fly ash, as was recently demonstrated by CONSOL R&D on a slip-stream pilot plant at the Allegheny Energy Mitchell Station with partial support by DOE. LTMC has the potential to remove over 90 percent of the flue gas mercury at a cost at least an order of magnitude lower (on a $/lb mercury removed basis) than activated carbon injection. The technology is suitable for retrofitting to existing and new plants, and, although it is best suited to bituminous coal-fired plants, it may have some applicability to the full range of coal types. Installation plans were altered and moved from the original project host site, PPL Martins Creek plant, to a second host site at Allegheny Energy's R. Paul Smith plant, before installation actually occurred at the Jamestown (New York) Board of Public Utilities (BPU) Samuel A. Carlson (Carlson) Municipal Generating Station Unit 12, where the LTMC system was operated on a limited basis. At Carlson, over 60% mercury removal was demonstrated by cooling the flue gas to 220-230°F at the ESP inlet via humidification. The host unit ESP operation was unaffected by the humidification and performed satisfactorily at low temperature conditions.

  2. ARTROC—a readout ASIC for GEM-based full-field XRF imaging system

    Science.gov (United States)

    Fiutowski, T.; Koperny, S.; Łach, B.; Mindur, B.; Świentek, K.; Wiącek, P.; Dąbrowski, W.

    2017-12-01

    In the paper we report on development of an Application Specific Integrated Circuit (ASIC), called ARTROC, being part of a full-field X-ray fluorescence spectroscopy (XRF) imaging system equipped with a standard three stage Gas Electron Multiplier (GEM) detector of 10×10 cm2 area. The ARTROC consists of 64 independent channels, allowing for simultaneous recording of the amplitudes (energy sub-channel) and time stamps (timing sub-channel) of incoming signals. Thanks to the implemented token-based read out of derandomizing buffers, the ASIC also provides data sparsification and full zero suppression. Reconstruction of the hit positions is performed in an external data acquisition system by matching the time stamps of signals recorded in X- and Y-strips. The amplitude information is used for centre of gravity finding in clusters of signals on neighbouring strips belonging to the same detection events. The ASIC could work in one of six gain modes and one of two speed modes. In a slower mode the maximum count rate per channel is 105/s while in a faster mode it is three times higher. The ARTROC comprises also input protection circuits against possible random discharges inside active detector volume, so it can be used without any additional input components. The ASIC has been designed in 350 nm CMOS process. The basic functionality and parameters have been evaluated using the testability functions implemented in the ASIC design. The ASIC has been also tested in a fully equipped GEM detector set-up with X-rays source.

  3. Suspicious amorphous microcalcifications detected on full-field digital mammography: correlation with histopathology

    Directory of Open Access Journals (Sweden)

    Vera Christina Camargo de Siqueira Ferreira

    2018-03-01

    Full Text Available Abstract Objective: To evaluate suspicious amorphous calcifications diagnosed on full-field digital mammography (FFDM and establish correlations with histopathology findings. Materials and Methods: This was a retrospective study of 78 suspicious amorphous calcifications (all classified as BI-RADS® 4 detected on FFDM. Vacuum-assisted breast biopsy (VABB was performed. The histopathological classification of VABB core samples was as follows: pB2 (benign; pB3 (uncertain malignant potential; pB4 (suspicion of malignancy; and pB5 (malignant. Treatment was recommended for pB5 lesions. To rule out malignancy, surgical excision was recommended for pB3 and pB4 lesions. Patients not submitted to surgery were followed for at least 6 months. Results: Among the 78 amorphous calcifications evaluated, the histopathological analysis indicated that 8 (10.3% were malignant/suspicious (6 classified as pB5 and 2 classified as pB4 and 36 (46.2% were benign (classified as pB2. The remaining 34 lesions (43.6% were classified as pB3: 33.3% were precursor lesions (atypical ductal hyperplasia, lobular neoplasia, or flat epithelial atypia and 10.3% were high-risk lesions. For the pB3 lesions, the underestimation rate was zero. Conclusion: The diagnosis of precursor lesions (excluding atypical ductal hyperplasia, which can be pB4 depending on the severity and extent of the lesion should not necessarily be considered indicative of underestimation of malignancy. Suspicious amorphous calcifications correlated more often with precursor lesions than with malignant lesions, at a ratio of 3:1.

  4. Fractal analysis of en face tomographic images obtained with full field optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wanrong; Zhu, Yue [Department of Optical Engineering, Nanjing University of Science and Technology, Jiangsu (China)

    2017-03-15

    The quantitative modeling of the imaging signal of pathological areas and healthy areas is necessary to improve the specificity of diagnosis with tomographic en face images obtained with full field optical coherence tomography (FFOCT). In this work, we propose to use the depth-resolved change in the fractal parameter as a quantitative specific biomarker of the stages of disease. The idea is based on the fact that tissue is a random medium and only statistical parameters that characterize tissue structure are appropriate. We successfully relate the imaging signal in FFOCT to the tissue structure in terms of the scattering function and the coherent transfer function of the system. The formula is then used to analyze the ratio of the Fourier transforms of the cancerous tissue to the normal tissue. We found that when the tissue changes from the normal to cancerous the ratio of the spectrum of the index inhomogeneities takes the form of an inverse power law and the changes in the fractal parameter can be determined by estimating slopes of the spectra of the ratio plotted on a log-log scale. The fresh normal and cancer liver tissues were imaged to demonstrate the potential diagnostic value of the method at early stages when there are no significant changes in tissue microstructures. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Development of PZT-excited stroboscopic shearography for full-field nondestructive evaluation

    Science.gov (United States)

    Asemani, Hamidreza; Park, Jinwoo; Lee, Jung-Ryul; Soltani, Nasser

    2017-05-01

    Nondestructive evaluation using shearography requires a way to stress the inspection target. This technique is able to directly measure the displacement gradient distribution on the object surface. Shearography visualizes the internal structural damages as the anomalous pattern in the shearograpic fringe pattern. A piezoelectric (PZT) excitation system is able to generate loadings in the vibrational, acoustic, and ultrasonic regimes. In this paper, we propose a PZT-excited stroboscopic shearography. The PZT excitation could generate vibrational loading, a stationary wavefield, and a nonstationary propagation wave to fulfill the external loading requirement of shearography. The sweeping of the PZT excitation frequency, the formation of a standing wave, and a small shearing to suppress the incident wave were powerful controllable tools to detect the defects. The sweeping of the PZT excitation frequency enabled us to determine one of the defect-sensitive frequencies almost in real time. In addition, because the defect sensitive frequencies always existed in wide and plural ranges, the risk of the defect being overlooked by the inspector could be alleviated. The results of evaluation using stroboscopic shearography showed that an artificial 20 mm-diameter defect could be visualized at the excitation frequencies of 5-8 kHz range and 12.5-15.5 kHz range. This technique provided full field reliable and repeatable inspection results. Additionally, the proposed method overcame the important drawback of the time-averaged shearography, being required to identify the resonance vibration frequency sensitive to the defect.

  6. Performance comparison of full-field digital mammography to screen-film mammography in clinical practice

    International Nuclear Information System (INIS)

    Berns, Eric A.; Hendrick, R. Edward; Cutter, Gary R.

    2002-01-01

    Results of acceptance testing 18 full-field digital mammography systems for clinical use and of conducting annual physics surveys of 38 screen-film mammography systems were compared in terms of exposure times, mean glandular breast doses, and image quality. These evaluations were made using the same test tools on all systems, with emphasis on assessing automatic exposure control performance and image quality on both digital and screen-film systems using clinical techniques. Survey results indicated that digital mammography systems performed similarly to screen-film systems in terms of exposure times and mean glandular doses for thin to intermediate breasts, but that digital mammography systems selected shorter exposure times and lower mean glandular doses for thicker breasts. For all breast thicknesses, digital mammography systems yielded mean contrast-detail scores higher than those for screen-film systems. For all breast thicknesses, the 18 digital mammography systems demonstrated less variance in terms of exposure times, mean glandular doses, and contrast-detail scores than did the 38 screen-film systems tested. These results indicate that the clinical use of digital mammography may generally improve image quality for equal or lower breast doses, while providing tighter control on exposures and image quality than screen-film mammography

  7. Characterization of microcalcification: can digital monitor zooming replace magnification mammography in full-field digital mammography?

    International Nuclear Information System (INIS)

    Kim, Min Jung; Kim, Eun-Kyung; Kwak, Jin Young; Son, Eun Ju; Youk, Ji Hyun; Choi, Seon Hyeong; Oh, Ki Keun; Han, Mooyoung

    2009-01-01

    The aim of this study was to compare the diagnostic accuracy and image quality of microcalcifications in zoomed digital contact mammography with digital magnification mammography. Three radiologists with different levels of experience in mammography reviewed 120 microcalcification clusters in 111 patients with a full-field digital mammography system relying on digital magnification mammogram (MAG) images and zoomed images from contact mammography (ZOOM) using commercially available zooming systems on monitors. Each radiologist estimated the probability of malignancy and rated the image quality and confidence rate. Performance was evaluated by sensitivity, specificity, positive predictive value, negative predictive value, and receiver operating characteristic (ROC) analysis. All three radiologists rated MAG images higher than ZOOM images for sensitivity with statistical significance (average value, 92% vs. 87%, P<0.05) and performance by ROC analysis improved with MAG imaging. The confidence rate for diagnosis decision and the assessment of lesion characteristics were also better in MAG images than in ZOOM images with statistical significance (P<0.0001). Digital magnification mammography can enhance diagnostic performance when characterizing microcalcifications. Images zoomed from digital contact mammography cannot serve as an alternative to direct magnification digital mammography. (orig.)

  8. Actinic imaging of native and programmed defects on a full-field mask

    Energy Technology Data Exchange (ETDEWEB)

    Mochi, I.; Goldberg, K. A.; Fontaine, B. La; Tchikoulaeva, A.; Holfeld, C.

    2010-03-12

    We describe the imaging and characterization of native defects on a full field extreme ultraviolet (EUV) mask, using several reticle and wafer inspection modes. Mask defect images recorded with the SEMA TECH Berkeley Actinic Inspection Tool (AIT), an EUV-wavelength (13.4 nm) actinic microscope, are compared with mask and printed-wafer images collected with scanning electron microscopy (SEM) and deep ultraviolet (DUV) inspection tools. We observed that defects that appear to be opaque in the SEM can be highly transparent to EUV light, and inversely, defects that are mostly transparent to the SEM can be highly opaque to EUV. The nature and composition of these defects, whether they appear on the top surface, within the multilayer coating, or on the substrate as buried bumps or pits, influences both their significance when printed, and their detectability with the available techniques. Actinic inspection quantitatively predicts the characteristics of printed defect images in ways that may not be possible with non-EUV techniques. As a quantitative example, we investigate the main structural characteristics of a buried pit defect based on EUV through-focus imaging.

  9. Pulsating electromagnetic fields (PEMF) used to treat full thickness defects in the rabbit model

    Energy Technology Data Exchange (ETDEWEB)

    Andino, R.V.; Feldman, D. (Univ. of Alabama, Birmingham (United States))

    1991-03-15

    Skin ulcers have historically been treated by passive therapy. One active treatment, PEMF, has shown promise. The objective of this study was, therefore, to examine the effects of a current induced by a PEMF on full thickness defects in white New Zealand rabbits. It was hypothesized that the induced current would increase neutrophil, macrophage, and fibroblast proliferation during the wound healing process. This in turn, would lead to an increase in collagen deposition in the wound and thus increase the healing rate. A device which produces a 2.8 mTesla magnetic field at a frequency of 75 Hz was donated by the EBI Corp. and modified so that a rabbit could be fit between its two induction coils. Two rabbits with four 3 x 3 cm wounds each were stimulated for 3.5 hours/day for 1 week and two rabbits with identical wounds were stimulated for the same time period daily but for 2 weeks. These wounds were compared to unstimulated controls. Preliminary results indicate that the healing rate in the PEMF animals increased by about 25-30% and the number of neutrophils is greater in the one week stimulated group. In the two week stimulated group, the collagen deposition is greater, denser and in alignment.

  10. Skin cancer margin analysis within minutes with full-field OCT (Conference Presentation)

    Science.gov (United States)

    Dalimier, Eugénie; Ogrich, Lauren; Morales, Diego; Cusack, Carrie Ann; Abdelmalek, Mark; Boccara, Claude; Durkin, John

    2017-02-01

    Non-melanoma skin cancer (NMSC) is the most common cancer. Treatment consists of surgical removal of the skin cancer. Traditional excision involves the removal of the visible skin cancer with a significant margin of normal skin. On cosmetically sensitive areas, Mohs micrographic tissue is the standard of care. Mohs uses intraoperative microscopic margin assessment which minimizes the surgical defect and can help reduce the recurrence rate by a factor of 3. The current Mohs technique relies on frozen section tissue slide preparation which significantly lengthens operative time and requires on-site trained histotechnicians. Full-Field Optical Coherence Tomography (FFOCT) is a novel optical imaging technique which provides a quick and efficient method to visualize cancerous areas in minutes, without any preparation or destruction of the tissue. This study aimed to evaluate the potential of FFOCT for the analysis of skin cancer margins during Mohs surgery. Over 150 images of Mohs specimens were acquired intraoperatively with FFOCT before frozen section analysis. The imaging procedure took less than 5 minutes for each specimen. No artifacts on histological preparation were found arising from FFOCT manipulation; however frozen section artifact was readily seen on FFOCT. An atlas was established with FFOCT images and corresponding histological slides to reveal FFOCT reading criteria of normal and cancerous structures. Blind analysis showed high concordance between FFOCT and histology. FFOCT can potentially reduce recurrence rates while maintaining short surgery times, optimize clinical workflow, and decrease healthcare costs. For the patient, this translates into smaller infection risk, decreased stress, and better comfort.

  11. Breast Glandularity in Malaysian Women from a Full-Field Digital Mammography System

    International Nuclear Information System (INIS)

    Noriah Jamal; Humairah Samad Cheung; Siti Selina Abdul Hamid; Juliana Mahamad Napiah

    2014-01-01

    This study is undertaken to estimate breast glandularity in Malaysian women from a Full-Field Digital mammography System. This study involved 223 women (Malay=100;Chinese=101 and Indian=22) underwent voluntary screening mammography at Breast Centre, International Islamic University Malaysia (IIUM Breast Centre) for the first quarter of year 2009. Those are women aged between 31 to 69 years old (median age, 49 years). Data on miliampere-seconds, kilo voltage and compressed breast thickness for each cranio caudal view are used to estimate breast glandularity for an individual breast. Breast glandularity is calculated using the fitted equation reported earlier. The difference in breast glandularity among ethnic groups was tested for significance using the nonparametric Kruskal-Wallis test. The average breast glandularity estimated in our study, using FFDM system is 52.94±27.63 %. No significant difference was seen in breast glandularity among the ethnic groups (p>0.05, Kruskan Wallis test). Breast glandularity decrease as age increases, up to 60 years old. (author)

  12. Homogenization of linear viscoelastic three phase media: internal variable formulation versus full-field computation

    International Nuclear Information System (INIS)

    Blanc, V.; Barbie, L.; Masson, R.

    2011-01-01

    Homogenization of linear viscoelastic heterogeneous media is here extended from two phase inclusion-matrix media to three phase inclusion-matrix media. Each phase obeying to a compressible Maxwellian behaviour, this analytic method leads to an equivalent elastic homogenization problem in the Laplace-Carson space. For some particular microstructures, such as the Hashin composite sphere assemblage, an exact solution is obtained. The inversion of the Laplace-Carson transforms of the overall stress-strain behaviour gives in such cases an internal variable formulation. As expected, the number of these internal variables and their evolution laws are modified to take into account the third phase. Moreover, evolution laws of averaged stresses and strains per phase can still be derived for three phase media. Results of this model are compared to full fields computations of representative volume elements using finite element method, for various concentrations and sizes of inclusion. Relaxation and creep test cases are performed in order to compare predictions of the effective response. The internal variable formulation is shown to yield accurate prediction in both cases. (authors)

  13. UV-laser induced birefringence in olygoetheracrylate photopolymers

    Science.gov (United States)

    Ozga, K.

    2018-01-01

    Laser induced birefringence was studied during coherent treatment by two coherent UV laser beams at wavelength 355 nm. Principal role of the border separating photo-solidified and the surrounding non-solidified liquid-like fragments is demonstrated. The magnitudes of laser induced birefringence for probing 1150 nm wavelength were varied within 10-4…10-2. It is demonstrated that one can operate by values of the birefringence versus polymer solidification time. The UV-induced birefringence achieves a saturation after about 45 days. The reversible birefringence after switching off of the UV-solidification beams was equal to about 18% with respect to initially photo-stimulated. The discovered effect may be used for design and fabrication of electro-optical modulators operated by UV laser light. A principal physical mechanism is determined by an interaction between two coherent UV- nanosecond laser pulses at wavelengths of 355 nm (third harmonic of Nd:YAG laser). The discovered effects allow to propose a new type of UV-operated photopolymer materials for optical recoding of information.

  14. 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.

  15. Full-field digital mammography versus computed radiology mammography: comparison in image quality and radiation dose

    International Nuclear Information System (INIS)

    Zhao Yongxia; Song Shaojuan; Liu Chuanya; Qi Hengtao; Qin Weichang

    2008-01-01

    Objective: To investigate the differences in image quality and radiation dose between full- field digital mammography (FFDM) system and compute radiology mammography (CRM) system. Methods: The ALVIM mammographic phantom was exposed by FFDM system with automatic exposure control (AEC) and then exposed by CRM system with the unique imaging plank on the same condition. The FFDM system applied the same kV value and the different mAs values (14, 16, 18, 22 and 24 mAs), and the emission skin dose (ESD) and the average gland dose (AGD) were recorded for the above-mentioned exposure factors. All images were read by five experienced radiologists under the same condition and judged based on 5-point scales. And then receive operating characteristic (ROC) curve was drawn and the probability (P det ) values were calculated. The data were statistically processed with ANOVA. Results: The P det values of calcifications and lesion lump were higher with FFDM system than with CRM system at the same dose (1.36 mGy). Especially, for microcalcifications and lesion lump, the largest difference of the P det value was 0.215, and that of lesion lump was 0.245. In comparison with CRM system, the radiation dose of FFDM system could be reduced at the same P det value. The ESD value was reduced by 26%, and the ACD value was reduced by 41%. When the mAs value exceed AEC value, the P det value almost had no change, though the radiation dose was increased. Conclusions: The detection rates of microcalcifications and lesion lump with FFDM system are proven to be superior to CRM system at the same dose. The radiation dose of FFDM system was less than CRM system for the same image quality. (authors)

  16. Evaluation of the potential in radiation dose reduction for full-field digital mammography

    International Nuclear Information System (INIS)

    Kasch, K-U.; Moftah, B.

    2008-01-01

    This study evaluates the image quality for different radiation doses in full-field digital mammography (FFDM). The potential of dose reductions is evaluated for both, the transition from screen-film mammography (SFM) to FFDM as well as within FFDM due to the optimization of exposure parameters. Exposures of a 4.5 cm breast phantom rendering different contrasts as well as bar patterns were made using a FFDM system (GE Senographe 2000D). For different kVp and mAs settings as well as different target/filter combinations chosen for the above exposures, average glandular dose (AGD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and modulation transfer function (MTF) were determined. To benchmark the results, relative change of AGD was evaluated against SNR, CNR and MTF. Eventually, the results were normalized to AGD's rendered by settings typically used in today's clinical routine. For standard settings (automatic mode), both FFDM and SFM deliver approximately the same AGD of about 2.2 mGy. From that, AGD reduction can be substantial in FFDM if only SNR and high contrast CNR are considered. In this case, reduction of up to 40% can be achieved in a wide kVp range if switching from the standard target/filter combination Mo/Rh to Rh/Rh. However, if low contrast CNR is to remain unchanged, dose reduction is practically impossible. The change of peak voltage and target/filter material had no influence on MTF. Assuming current CNR requirements as standards, significant dose reduction in FFDM cannot be achieved. Only by compromising low contrast CNR levels AGD of up to 40% can be saved at current standards of SNR and high contrast CNR. (author)

  17. Computer-aided detection system applied to full-field digital mammograms

    Energy Technology Data Exchange (ETDEWEB)

    Vega Bolivar, Alfonso; Sanchez Gomez, Sonia; Merino, Paula; Alonso-Bartolome, Pilar; Ortega Garcia, Estrella (Dept. of Radiology, Univ. Marques of Valdecilla Hospital, Santander (Spain)), e-mail: avegab@telefonica.net; Munoz Cacho, Pedro (Dept. of Statistics, Univ. Marques of Valdecilla Hospital, Santander (Spain)); Hoffmeister, Jeffrey W. (iCAD, Inc., Nashua, NH (United States))

    2010-12-15

    Background: Although mammography remains the mainstay for breast cancer screening, it is an imperfect examination with a sensitivity of 75-92% for breast cancer. Computer-aided detection (CAD) has been developed to improve mammographic detection of breast cancer. Purpose: To retrospectively estimate CAD sensitivity and false-positive rate with full-field digital mammograms (FFDMs). Material and Methods: CAD was used to evaluate 151 cases of ductal carcinoma in situ (DCIS) (n=48) and invasive breast cancer (n=103) detected with FFDM. Retrospectively, CAD sensitivity was estimated based on breast density, mammographic presentation, histopathology type, and lesion size. CAD false-positive rate was estimated with screening FFDMs from 200 women. Results: CAD detected 93% (141/151) of cancer cases: 97% (28/29) in fatty breasts, 94% (81/86) in breasts containing scattered fibroglandular densities, 90% (28/31) in heterogeneously dense breasts, and 80% (4/5) in extremely dense breasts. CAD detected 98% (54/55) of cancers manifesting as calcifications, 89% (74/83) as masses, and 100% (13/13) as mixed masses and calcifications. CAD detected 92% (73/79) of invasive ductal carcinomas, 89% (8/9) of invasive lobular carcinomas, 93% (14/15) of other invasive carcinomas, and 96% (46/48) of DCIS. CAD sensitivity for cancers 1-10 mm was 87% (47/54); 11-20 mm, 99% (70/71); 21-30 mm, 86% (12/14); and larger than 30 mm, 100% (12/12). The CAD false-positive rate was 2.5 marks per case. Conclusion: CAD with FFDM showed a high sensitivity in identifying cancers manifesting as calcifications or masses. CAD sensitivity was maintained in small lesions (1-20 mm) and invasive lobular carcinomas, which have lower mammographic sensitivity

  18. Computer-aided detection system applied to full-field digital mammograms

    International Nuclear Information System (INIS)

    Vega Bolivar, Alfonso; Sanchez Gomez, Sonia; Merino, Paula; Alonso-Bartolome, Pilar; Ortega Garcia, Estrella; Munoz Cacho, Pedro; Hoffmeister, Jeffrey W.

    2010-01-01

    Background: Although mammography remains the mainstay for breast cancer screening, it is an imperfect examination with a sensitivity of 75-92% for breast cancer. Computer-aided detection (CAD) has been developed to improve mammographic detection of breast cancer. Purpose: To retrospectively estimate CAD sensitivity and false-positive rate with full-field digital mammograms (FFDMs). Material and Methods: CAD was used to evaluate 151 cases of ductal carcinoma in situ (DCIS) (n=48) and invasive breast cancer (n=103) detected with FFDM. Retrospectively, CAD sensitivity was estimated based on breast density, mammographic presentation, histopathology type, and lesion size. CAD false-positive rate was estimated with screening FFDMs from 200 women. Results: CAD detected 93% (141/151) of cancer cases: 97% (28/29) in fatty breasts, 94% (81/86) in breasts containing scattered fibroglandular densities, 90% (28/31) in heterogeneously dense breasts, and 80% (4/5) in extremely dense breasts. CAD detected 98% (54/55) of cancers manifesting as calcifications, 89% (74/83) as masses, and 100% (13/13) as mixed masses and calcifications. CAD detected 92% (73/79) of invasive ductal carcinomas, 89% (8/9) of invasive lobular carcinomas, 93% (14/15) of other invasive carcinomas, and 96% (46/48) of DCIS. CAD sensitivity for cancers 1-10 mm was 87% (47/54); 11-20 mm, 99% (70/71); 21-30 mm, 86% (12/14); and larger than 30 mm, 100% (12/12). The CAD false-positive rate was 2.5 marks per case. Conclusion: CAD with FFDM showed a high sensitivity in identifying cancers manifesting as calcifications or masses. CAD sensitivity was maintained in small lesions (1-20 mm) and invasive lobular carcinomas, which have lower mammographic sensitivity

  19. Postoperative changes in the full-field electroretinogram following sevoflurane anaesthesia.

    LENUS (Irish Health Repository)

    Iohom, G

    2012-02-03

    BACKGROUND AND OBJECTIVE: We tested the hypothesis that disturbances of the visual pathway persist following general anaesthesia, even after normal clinical discharge criteria have been met. METHODS: We performed full-field flash electroretinography in the right eye of 10 unpremedicated ASA I patients who underwent N2O\\/sevoflurane anaesthesia. Electroretinograms were recorded preoperatively, immediately after discharge from the recovery room and 2 h after discontinuation of sevoflurane. The time at which postanaesthesia discharge score first exceeded 9 was also noted. Data were analysed using paired, one-tailed Student\\'s t-test. RESULTS: Latency of the b-wave on the photopic electroretinogram was greater at each postoperative time point (30.5 +\\/- 0.9 and 30 +\\/- 1.3 ms), compared to preoperative values (29.2 +\\/- 0.8 ms, P < 0.001 and P = 0.04, respectively). The A-B amplitude of the b-wave was less postoperatively (220.3 +\\/- 52.7 and 210.3 +\\/- 42.7 pV) compared to values before operation (248.1 +\\/- 57.6 microV, P = 0.03 and P = 0.01, respectively). Oscillatory potential latencies were greater at each postoperative time point (21.4 +\\/- 0.5 and 20.8 +\\/- 0.6 ms) compared to before operation (20.4 +\\/- 0.4 ms, P < 0.001 and P = 0.03, respectively). Oscillatory potential amplitudes were less at the first postoperative time point (17.5 +\\/- 6.1 microV), compared to preoperative values (22 +\\/- 6.4 microV, P = 0.04). CONCLUSIONS: Postoperative electroretinogram abnormalities are consistently present in patients who have undergone N2O\\/sevoflurane anaesthesia. These abnormalities persist beyond the time at which standard clinical discharge criteria have been met.

  20. Full-field illumination approach with multiple speckle for optical-resolution photoacoustic microscopy (Conference Presentation)

    Science.gov (United States)

    Poisson, Florian; Bossy, Emmanuel

    2016-03-01

    Optical-resolution photoacoustic endomicroscopy (OR-PAE) allows going beyond the limited penetration depth of conventional optical-resolution photoacoustic systems. Recently, it has been shown that OR-PAE may be performed through minimally invasive multimode fibers, by raster scanning a focus spot with optical wavefront shaping [1]. Here we introduce for the first time an approach to perform OR-PAE through a multimode fiber with a full-field illumination approach. By using multiple known speckle patterns, we show that it is possible to obtain optical-diffraction limited photoacoustic images, with the same resolution as that obtained by raster scanning a focus spot, i.e that of the speckle grain size. The fluctuations patterns of the photoacoustic amplitude at each pixel in the sample plane with the series of multiple speckle illumination were used to encode each pixel. This approach with known speckle illumination requires an initial calibration stage, that consists in learn a set of fluctuation patterns pixel per pixel, which will encode patterns each pixel of the scanned area. A point-like absorber was scanned across the filed-of-view during the calibration stage to acquire the reference patterns. Image reconstruction may be carried out by cross-correlating the series of photoacoustic amplitude measured with the sample to the reference patterns obtained during the calibration stage. In this work, the approach above was carried out both theoretically with Monte-carlo simulations and experimentally through a multi-mode fiber with samples made of absorbing spheres. [1] Papadopoulos et al., " Optical-resolution photoacoustic microscopy by use of a multimode fiber", Appl. Phys. Lett., 102(21), 2013

  1. Impact of full field digital mammography on the classification and mammographic characteristics of interval breast cancers

    International Nuclear Information System (INIS)

    Knox, Mark; O’Brien, Angela; Szabó, Endre; Smith, Clare S.; Fenlon, Helen M.; McNicholas, Michelle M.; Flanagan, Fidelma L.

    2015-01-01

    Highlights: • Digital mammography has changed the presentation of interval breast cancer. • Less interval breast cancers are associated with microcalcifications following FFDM. • Interval breast cancer audit remains a key feature of any breast screening program. - Abstract: Objective: Full field digital mammography (FFDM) is increasingly replacing screen film mammography (SFM) in breast screening programs. Interval breast cancers are an issue in all screening programs and the purpose of our study is to assess the impact of FFDM on the classification of interval breast cancers at independent blind review and to compare the mammographic features of interval cancers at FFDM and SFM. Materials and methods: This study included 138 cases of interval breast cancer, 76 following an FFDM screening examination and 62 following screening with SFM. The prior screening mammogram was assessed by each of five consultant breast radiologists who were blinded to the site of subsequent cancer. Subsequent review of the diagnostic mammogram was performed and cases were classified as missed, minimal signs, occult or true interval. Mammographic features of the interval cancer at diagnosis and any abnormality identified on the prior screening mammogram were recorded. Results: The percentages of cancers classified as missed at FFDM and SFM did not differ significantly, 10.5% (8 of 76) at FFDM and 8.1% (5 of 62) at SFM (p = .77). There were significantly less interval cancers presenting as microcalcifications (alone or in association with another abnormality) following screening with FFDM, 16% (12 of 76) than following a SFM examination, 32% (20 of 62) (p = .02). Conclusion: Interval breast cancers continue to pose a problem at FFDM. The switch to FFDM has changed the mammographic presentation of interval breast cancer, with less interval cancers presenting in association with microcalcifications

  2. Digital full field mammography for imaging augmented breasts; Digitale Vollfeldmammographie nach Brustaugmentation

    Energy Technology Data Exchange (ETDEWEB)

    Diekmann, S.; Diekmann, F.; Hamm, B. [Institut fuer Radiologie, Universitaetsklinikum Charite, Berlin (Germany); Hauschild, M. [Klinik fuer Frauenheilkunde und Geburtshilfe, Universitaetsklinikum Charite, Berlin (Germany)

    2002-04-01

    Purpose. The use of digital full field mammography for imaging augmented breasts.Methods. Images of a sponge, as a tissue equivalent, partly covered with one of three different implants (silicone, silicone/saline, saline) were obtained using digital and film-screen technique. The visualisation of the sponge structure covered by the implant and next to the implant was evaluated by two radiologists. Results were compared to clinical results from 35 patients with implants.Results. Two images with different parameter settings have to be obtained to visualize the covered sponge structure and the structure around the implant with film-screen technique. Digital mammography allows assessment of both areas using one image at different window settings. The assessability of covered structures depends on the type of implant. These results are in keeping with our clinical experiences.Conclusion. Digital mammography allows equal or better assessment of covered and non-covered tissue in augmented breasts without the need for additional exposures. (orig.) [German] Fragestellung. Anwendung der digitalen Vollfeldmammographie nach Mammaaugmentation mit verschiedenen Implantaten.Methodik. In einem Phantomversuch wurde ein Schwamm (Gewebeaequivalent) ueberlagert von 3 verschiedenen Implantaten (Silikon, Silikon/Kochsalz, Kochsalz) in konventioneller und digitaler Technik mit gleichen Parametern geroentgt. Es wurde die Beurteilbarkeit der Schwammstruktur neben und unter dem Implantat in beiden Techniken durch 2 Reader geprueft und den klinischen Erfahrungen bei 35 Patientinnen mit Mammaaugmentation gegenuebergestellt.Ergebnisse. Fuer die Beurteilung von verdecktem Gewebe und unverdecktem Gewebe (simuliert durch den Schwamm) muessen mit konventioneller Film-Folien-Technik zumindest 2 Aufnahmen mit verschiedenen Belichtungsparametern erstellt werden, waehrend durch eine geeignete Fensterung beides mit einer digitalen Aufnahme beurteilt werden kann. Die Beurteilbarkeit der ueberlagerten

  3. Quality control and primo-diagnosis of transurethral bladder resections with full-field OCT

    Science.gov (United States)

    Montagne, P.; Ducesne, I.; Anract, J.; Yang, C.; Sibony, M.; Beuvon, F.; Delongchamps, N. B.; Dalimier, E.

    2017-02-01

    Transurethral resections are commonly used for bladder cancer diagnosis, treatment and follow-up. Cancer staging relies largely on the analysis of muscle in the resections; however, muscle presence is uncertain at the time of the resection. An extemporaneous quality control tool would be of great use to certify the presence of muscle in the resection, and potentially formulate a primo-diagnosis, in order to ensure optimum patient care. Full-field optical coherence tomography (FFOCT) offers a fast and non-destructive method of obtaining images of biological tissues at ultrahigh resolution (1μm in all 3 directions), approaching traditional histological sections. This study aimed to evaluate the potential of FFOCT for the quality control and the primo-diagnosis of transurethral bladder resections. Over 70 transurethral bladder resections were imaged with FFOCT within minutes, shortly after excision, and before histological preparation. Side-by-side comparison with histology allowed to establish reading criteria for the presence of muscle and cancer in particular. Images of 24 specimens were read blindly by three non-pathologists readers: two resident urologists and a junior bio-medical engineer, who were asked to notify the presence of muscle and tumor. Results showed that after appropriate training, 96% accuracy could be obtained on both tumour and muscle detection. FFOCT is a fast and nondestructive imaging technique that provides analysis results concordant with histology. Its implementation as a quality control and primo-diagnosis tool for transurethral bladder resections in the urology suite is feasible and lets envision high value for the patient.

  4. Comparison of dry laser printer versus paper printer in full-field digital mammography.

    Science.gov (United States)

    Liang, Zhigang; Du, Xiangying; Guo, Xiaojuan; Rong, Dongdong; Kang, Ruiying; Mao, Guangyun; Liu, Jiabin; Li, Kuncheng

    2010-04-01

    Paper printers have been used to document radiological findings in some hospitals. It is critical to establish whether paper printers can achieve the same efficacy and quality as dry laser printers for full-field digital mammography (FFDM). To compare the image quality and detection rate of dry laser printers and paper printers for FFDM. Fifty-five cases (25 with single clustered microcalcifications and 30 controls) were selected by a radiologist not participating in the image review. All images were printed on film and paper by one experienced mammography technologist using the processing algorithm routinely used for our mammograms. Two radiologists evaluated hard copies from dry laser printers and paper printers for image quality and detectability of clustered microcalcifications. For the image quality comparisons, agreement between the reviewers was evaluated by means of kappa statistics. The significance of differences between both of the printers was determined using Wilcoxon's signed-rank test. The detection rate of two printing systems was evaluated using receiver operating characteristic (ROC) analysis. From 110 scores (55 patients, two readers) per printer system, the following quality results were achieved for dry laser printer images: 70 (63.6%) were rated as good and 40 (36.4%) as moderate. By contrast, for the paper printer images, 25 scores (22.7%) were rated as good and 85 (77.3%) as moderate. Therefore, the image quality of the dry laser printer was superior to that achieved by the paper printer (P=0.00). The average area-under-the-curve (Az) values for the dry laser printer and the paper printer were 0.991 and 0.805, respectively. The difference was 0.186. Results of ROC analysis showed significant difference in observer performance between the dry laser printer and paper printer (P=0.0015). The performance of dry laser printers is superior to that of paper printers. Paper printers should not be used in FFDM.

  5. Image Enhancement and Speckle Reduction of Full Polarimetric SAR Data by Gaussian Markov Random Field

    Science.gov (United States)

    Mahdian, M.; Motagh, M.; Akbari, V.

    2013-09-01

    In recent years, the use of Polarimetric Synthetic Aperture Radar (PolSAR) data in different applications dramatically has been increased. In SAR imagery an interference phenomenon with random behavior exists which is called speckle noise. The interpretation of data encounters some troubles due to the presence of speckle which can be considered as a multiplicative noise affecting all coherent imaging systems. Indeed, speckle degrade radiometric resolution of PolSAR images, therefore it is needful to perform speckle filtering on the SAR data type. Markov Random Field (MRF) has proven to be a powerful method for drawing out eliciting contextual information from remotely sensed images. In the present paper, a probability density function (PDF), which is fitted well with the PolSAR data based on the goodness-of-fit test, is first obtained for the pixel-wise analysis. Then the contextual smoothing is achieved with the MRF method. This novel speckle reduction method combines an advanced statistical distribution with spatial contextual information for PolSAR data. These two parts of information are combined based on weighted summation of pixel-wise and contextual models. This approach not only preserves edge information in the images, but also improves signal-to-noise ratio of the results. The method maintains the mean value of original signal in the homogenous areas and preserves the edges of features in the heterogeneous regions. Experiments on real medium resolution ALOS data from Tehran, and also high resolution full polarimetric SAR data over the Oberpfaffenhofen test-site in Germany, demonstrate the effectiveness of the algorithm compared with well-known despeckling methods.

  6. Computer-aided detection in direct digital full-field mammography: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Baum, F.; Fischer, U.; Obenauer, S.; Grabbe, E. [Department of Radiology, Georg-August-Universitaet Goettingen, Robert-Koch-Strasse 40, 37075 Goettingen (Germany)

    2002-12-01

    For the first time, full-field digital mammography (FFDM) allows computer-aided detection (CAD) analysis of directly acquired digital image data. The purpose of this study was to evaluate a CAD system in patients with histologically correlated breast cancer depicted with FFDM. Sixty-three cases of histologically proven breast cancer detected with FFDM (Senographe 2000D, GE Medical Systems, Buc, France) were analyzed using a CAD system (Image Checker V2.3, R2 Technology, Los Altos, Calif.). Fourteen of these malignancies were characterized as microcalcifications, 37 as masses, and 12 as both. The mammographic findings were categorized as BI-RADS 3 (n=5), BI-RADS 4 (n=17) and BI-RADS 5 (n=40). The sensitivity for malignant lesions and the rate of false-positive marks per image were calculated. The sensitivity and its 95% confidence interval (CI) were estimated. The sensitivity of the CAD R2 system in breast cancer seen on FFDM was 89% for microcalcifications [CI{sub 95%}=(70%; 98%)] and 81% for masses [CI{sub 95%}=(67%; 91%)]. As expected, the detection rate was higher in lesions categorized as BI-RADS 5 (37 of 40) compared with lesions categorized as BI-RADS 4 (11 of 17). In the group categorized as BI-RADS 3 the detection rate was 4 of 5 lesions; however, this group was very small. The rate of false-positive marks was 0.35 microcalcification marks/image and 0.26 mass marks/image. The overall rate of false-positive marks was 0.61 per image. CAD based on FFDM provides an optimized work flow. Results are equivalent to the results reported for CAD analysis of secondarily digitized image data. Sensitivity for microcalcifications is acceptable and for masses is low. The number of false-positive marks per image should be reduced. (orig.)

  7. Full Field X-Ray Fluorescence Imaging Using Micro Pore Optics for Planetary Surface Exploration

    Science.gov (United States)

    Sarrazin, P.; Blake, D. F.; Gailhanou, M.; Walter, P.; Schyns, E.; Marchis, F.; Thompson, K.; Bristow, T.

    2016-01-01

    Many planetary surface processes leave evidence as small features in the sub-millimetre scale. Current planetary X-ray fluorescence spectrometers lack the spatial resolution to analyse such small features as they only provide global analyses of areas greater than 100 mm(exp 2). A micro-XRF spectrometer will be deployed on the NASA Mars 2020 rover to analyse spots as small as 120m. When using its line-scanning capacity combined to perpendicular scanning by the rover arm, elemental maps can be generated. We present a new instrument that provides full-field XRF imaging, alleviating the need for precise positioning and scanning mechanisms. The Mapping X-ray Fluorescence Spectrometer - "Map-X" - will allow elemental imaging with approximately 100µm spatial resolution and simultaneously provide elemental chemistry at the scale where many relict physical, chemical and biological features can be imaged in ancient rocks. The arm-mounted Map-X instrument is placed directly on the surface of an object and held in a fixed position during measurements. A 25x25 mm(exp 2) surface area is uniformly illuminated with X-rays or alpha-particles and gamma-rays. A novel Micro Pore Optic focusses a fraction of the emitted X-ray fluorescence onto a CCD operated at a few frames per second. On board processing allows measuring the energy and coordinates of each X-ray photon collected. Large sets of frames are reduced into 2d histograms used to compute higher level data products such as elemental maps and XRF spectra from selected regions of interest. XRF spectra are processed on the ground to further determine quantitative elemental compositions. The instrument development will be presented with an emphasis on the characterization and modelling of the X-ray focussing Micro Pore Optic. An outlook on possible alternative XRF imaging applications will be discussed.

  8. Comparison of tissue equalization, and premium view post-processing methods in full field digital mammography

    International Nuclear Information System (INIS)

    Chen Baoying; Wang Wei; Huang Jin; Zhao Ming; Cui Guangbin; Xu Jing; Guo Wei; Du Pang; Li Pei; Yu Jun

    2010-01-01

    Objective: To retrospectively evaluate the diagnostic abilities of 2 post-processing methods provided by GE Senographe DS system, tissue equalization (TE) and premium view (PV) in full field digital mammography (FFDM). Materials and methods: In accordance with the ethical standards of the World Medical Association, this study was approved by regional ethics committee and signed informed patient consents were obtained. We retrospectively reviewed digital mammograms from 101 women (mean age, 47 years; range, 23-81 years) in the modes of TE and PV, respectively. Three radiologists, fully blinded to the post-processing methods, all patient clinical information and histologic results, read images by using objective image interpretation criteria for diagnostic information end points such as lesion border delineation, definition of disease extent, visualization of internal and surrounding morphologic features of the lesions. Also, overall diagnostic impression in terms of lesion conspicuity, detectability and diagnostic confidence was assessed. Between-group comparisons were performed with Wilcoxon signed rank test. Results: Readers 1, 2, and 3 demonstrated significant overall better impression of PV in 29, 27, and 24 patients, compared with that for TE in 12, 13, and 11 patients, respectively (p < 0.05). Significant (p < 0.05) better impression of PV was also demonstrated for diagnostic information end points. Importantly, PV proved to be more sensitive than TE while detecting malignant lesions in dense breast rather than benign lesions and malignancy in non-dense breast (p < 0.01). Conclusion: PV compared with TE provides marked better diagnostic information in FFDM, particularly for patients with malignancy in dense breast.

  9. Global sensitivity analysis in the identification of cohesive models using full-field kinematic data

    KAUST Repository

    Alfano, Marco

    2015-03-01

    Failure of adhesive bonded structures often occurs concurrent with the formation of a non-negligible fracture process zone in front of a macroscopic crack. For this reason, the analysis of damage and fracture is effectively carried out using the cohesive zone model (CZM). The crucial aspect of the CZM approach is the precise determination of the traction-separation relation. Yet it is usually determined empirically, by using calibration procedures combining experimental data, such as load-displacement or crack length data, with finite element simulation of fracture. Thanks to the recent progress in image processing, and the availability of low-cost CCD cameras, it is nowadays relatively easy to access surface displacements across the fracture process zone using for instance Digital Image Correlation (DIC). The rich information provided by correlation techniques prompted the development of versatile inverse parameter identification procedures combining finite element (FE) simulations and full field kinematic data. The focus of the present paper is to assess the effectiveness of these methods in the identification of cohesive zone models. In particular, the analysis is developed in the framework of the variance based global sensitivity analysis. The sensitivity of kinematic data to the sought cohesive properties is explored through the computation of the so-called Sobol sensitivity indexes. The results show that the global sensitivity analysis can help to ascertain the most influential cohesive parameters which need to be incorporated in the identification process. In addition, it is shown that suitable displacement sampling in time and space can lead to optimized measurements for identification purposes.

  10. Magnetic field measurements of Fermilab/General Dynamics built full scale SSC collider dipole magnets

    International Nuclear Information System (INIS)

    Delchamps, S.; Bleadon, M.; Bossert, R.; Carson, J.; Gourlay, S.; Hanft, R.; Koska, W.; Kuchnir, M.; Lamm, M.J.; Mazur, P.O.; Mokhtarani, A.; Orris, D.; Strait, J.; Wake, M.; Devred, A.; DiMarco, J.; Kuzminski, J.; Ogitsu, T.; Puglisi, M.; Tompkins, J.C.; Yu, Y.; Zhao, Y.; Zheng, H.

    1992-01-01

    This paper presents preliminary results of magnetic field measurements made on a series of 50 mm aperture 15 m long SSC collider dipole magnets designed and manufactured at Fermi National Accelerator Laboratory (Fermilab) for use in the Superconducting Super Collider Laboratory (SSCL) Accelerator System String Test. The magnets were assembled by Fermilab and General Dynamics personnel, and were tested at the Magnet Test Facility (MTF) at Fermilab. Measurements of the dipole field angle, dipole field strength, and field shape parameters at various stages in magnet construction and testing are described

  11. A Novel Wavelength Demodulation Method Using Twisted High Birefringence Fiber

    International Nuclear Information System (INIS)

    Niu, L Y; Yang, H Y; Wu, F; Li, Z Q

    2006-01-01

    The mathematical model of twisted high birefringence fiber was established through theoretical analysis. A novel FBG wavelength demodulation method was put forward, by using the twisted high birefringence fiber. The numerical simulation and the experiments were carried out to the system. The standard cosine relationship was observed between the output intensity of polarization analyzer and the twist angle for the signal light with different wavelengths. When the twist angle of the high birefringence fiber is 0 and π/2, the output intensity ratio of the system presents the linear relationship with the wavelength approximately. The experiment shows that system is in agreement very well with theoretical analysis to demodulate guasi-linearly FBG wavelength shift in range of about 10 nm

  12. Coupled analysis between X-ray scattering and birefringence on an ionomer film

    Energy Technology Data Exchange (ETDEWEB)

    Heijden, P.C. van der [Structures et Proprietes d' Architectures Moleculaires, UMR 5819 (LEA, CNRS, UJF) DRFMC/SPrAM, CEA - Grenoble, 38054 Grenoble cedex 9 (France); Diat, O. [Structures et Proprietes d' Architectures Moleculaires, UMR 5819 (LEA, CNRS, UJF) DRFMC/SPrAM, CEA - Grenoble, 38054 Grenoble cedex 9 (France)]. E-mail: odiat@cea.fr

    2005-08-15

    Birefringence and orientation factor determined from scattering data analysis are correlated. The intrinsic birefringence from crystalline and amorphous phase in the Nafion, a benchmark ionomer system, were determined and compared with other values from literature.

  13. 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)

  14. Interferometric method for birefringence determination with a polarizing microscope.

    Science.gov (United States)

    Dumitraşcu, Leonaş; Dumitraşcu, Irina; Dorohoi, Dana-Ortansa; Toma, Mihai

    2008-12-08

    We present a new mathematical technique which can be used to determine the main refractive indices and the birefringence of an anisotropic layer by using a polarizing microscope in conoscopic illumination. The values of the birefringence for the yellow radiation of a Na lamp are determined here for a Carpathian quartz sample, but the technique can also be applied to the study of other uniaxial substances such as liquid crystals, model membranes or biological tissues. The validity of the proposed method was tested by comparing the results with those obtained with a Rayleigh interferometer and by using the technology of channeled spectra.

  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. Enabling full-field physics-based optical proximity correction via dynamic model generation

    Science.gov (United States)

    Lam, Michael; Clifford, Chris; Raghunathan, Ananthan; Fenger, Germain; Adam, Kostas

    2017-07-01

    As extreme ultraviolet lithography becomes closer to reality for high volume production, its peculiar modeling challenges related to both inter and intrafield effects have necessitated building an optical proximity correction (OPC) infrastructure that operates with field position dependency. Previous state-of-the-art approaches to modeling field dependency used piecewise constant models where static input models are assigned to specific x/y-positions within the field. OPC and simulation could assign the proper static model based on simulation-level placement. However, in the realm of 7 and 5 nm feature sizes, small discontinuities in OPC from piecewise constant model changes can cause unacceptable levels of edge placement errors. The introduction of dynamic model generation (DMG) can be shown to effectively avoid these dislocations by providing unique mask and optical models per simulation region, allowing a near continuum of models through the field. DMG allows unique models for electromagnetic field, apodization, aberrations, etc. to vary through the entire field and provides a capability to precisely and accurately model systematic field signatures.

  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. The OVAL experiment: a new experiment to measure vacuum magnetic birefringence using high repetition pulsed magnets

    Science.gov (United States)

    Fan, Xing; Kamioka, Shusei; Inada, Toshiaki; Yamazaki, Takayuki; Namba, Toshio; Asai, Shoji; Omachi, Junko; Yoshioka, Kosuke; Kuwata-Gonokami, Makoto; Matsuo, Akira; Kawaguchi, Koushi; Kindo, Koichi; Nojiri, Hiroyuki

    2017-11-01

    A new experiment to measure vacuum magnetic birefringence (VMB), the OVAL experiment, is reported. We developed an original pulsed magnet that has a high repetition rate and applies the strongest magnetic field among VMB experiments online. The vibration isolation design and feedback system enable the direct combination of the magnet with a Fabry-Pérot cavity. To demonstrate and benchmark the searching potential, a calibration measurement with dilute nitrogen gas and a prototype search for VMB are performed. Based on the results, a strategy to observe VMB is reported.

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

    Science.gov (United States)

    Yamazaki, T.; Inada, T.; Namba, T.; Asai, S.; Kobayashi, T.; Matsuo, A.; Kindo, K.; Nojiri, H.

    2016-10-01

    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.

  20. 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.

  1. Computer aided detection of clusters of microcalcifications on full field digital mammograms

    International Nuclear Information System (INIS)

    Ge Jun; Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, H.-P.; Wei Jun; Helvie, Mark A.; Zhou Chuan

    2006-01-01

    We are developing a computer-aided detection (CAD) system to identify microcalcification clusters (MCCs) automatically on full field digital mammograms (FFDMs). The CAD system includes six stages: preprocessing; image enhancement; segmentation of microcalcification candidates; false positive (FP) reduction for individual microcalcifications; regional clustering; and FP reduction for clustered microcalcifications. At the stage of FP reduction for individual microcalcifications, a truncated sum-of-squares error function was used to improve the efficiency and robustness of the training of an artificial neural network in our CAD system for FFDMs. At the stage of FP reduction for clustered microcalcifications, morphological features and features derived from the artificial neural network outputs were extracted from each cluster. Stepwise linear discriminant analysis (LDA) was used to select the features. An LDA classifier was then used to differentiate clustered microcalcifications from FPs. A data set of 96 cases with 192 images was collected at the University of Michigan. This data set contained 96 MCCs, of which 28 clusters were proven by biopsy to be malignant and 68 were proven to be benign. The data set was separated into two independent data sets for training and testing of the CAD system in a cross-validation scheme. When one data set was used to train and validate the convolution neural network (CNN) in our CAD system, the other data set was used to evaluate the detection performance. With the use of a truncated error metric, the training of CNN could be accelerated and the classification performance was improved. The CNN in combination with an LDA classifier could substantially reduce FPs with a small tradeoff in sensitivity. By using the free-response receiver operating characteristic methodology, it was found that our CAD system can achieve a cluster-based sensitivity of 70, 80, and 90 % at 0.21, 0.61, and 1.49 FPs/image, respectively. For case

  2. Computer aided detection of clusters of microcalcifications on full field digital mammograms.

    Science.gov (United States)

    Ge, Jun; Sahiner, Berkman; Hadjiiski, Lubomir M; Chan, Heang-Ping; Wei, Jun; Helvie, Mark A; Zhou, Chuan

    2006-08-01

    We are developing a computer-aided detection (CAD) system to identify microcalcification clusters (MCCs) automatically on full field digital mammograms (FFDMs). The CAD system includes six stages: preprocessing; image enhancement; segmentation of microcalcification candidates; false positive (FP) reduction for individual microcalcifications; regional clustering; and FP reduction for clustered microcalcifications. At the stage of FP reduction for individual microcalcifications, a truncated sum-of-squares error function was used to improve the efficiency and robustness of the training of an artificial neural network in our CAD system for FFDMs. At the stage of FP reduction for clustered microcalcifications, morphological features and features derived from the artificial neural network outputs were extracted from each cluster. Stepwise linear discriminant analysis (LDA) was used to select the features. An LDA classifier was then used to differentiate clustered microcalcifications from FPs. A data set of 96 cases with 192 images was collected at the University of Michigan. This data set contained 96 MCCs, of which 28 clusters were proven by biopsy to be malignant and 68 were proven to be benign. The data set was separated into two independent data sets for training and testing of the CAD system in a cross-validation scheme. When one data set was used to train and validate the convolution neural network (CNN) in our CAD system, the other data set was used to evaluate the detection performance. With the use of a truncated error metric, the training of CNN could be accelerated and the classification performance was improved. The CNN in combination with an LDA classifier could substantially reduce FPs with a small tradeoff in sensitivity. By using the free-response receiver operating characteristic methodology, it was found that our CAD system can achieve a cluster-based sensitivity of 70, 80, and 90 % at 0.21, 0.61, and 1.49 FPs/image, respectively. For case

  3. Compressive sensing of full wave field data for structural health monitoring applications

    DEFF Research Database (Denmark)

    di Ianni, Tommaso; De Marchi, Luca; Perelli, Alessandro

    2015-01-01

    Numerous nondestructive evaluations and structural health monitoring approaches based on guide waves rely on analysis of wave fields recorded through scanning laser Doppler vibrometers (SLDVs) or ultrasonic scanners. The informative content which can be extracted from these inspections is relevan...

  4. Compressive sensing of full wave field data for structural health monitoring applications.

    Science.gov (United States)

    Di Ianni, Tommaso; De Marchi, Luca; Perelli, Alessandro; Marzani, Alessandro

    2015-07-01

    Numerous nondestructive evaluations and structural health monitoring approaches based on guide waves rely on analysis of wave fields recorded through scanning laser Doppler vibrometers (SLDVs) or ultrasonic scanners. The informative content which can be extracted from these inspections is relevant; however, the acquisition process is generally time-consuming, posing a limit in the applicability of such approaches. To reduce the acquisition time, we use a random sampling scheme based on compressive sensing (CS) to minimize the number of points at which the field is measured. The CS reconstruction performance is mostly influenced by the choice of a proper decomposition basis to exploit the sparsity of the acquired signal. Here, different bases have been tested to recover the guided waves wave field acquired on both an aluminum and a composite plate. Experimental results show that the proposed approach allows a reduction of the measurement locations required for accurate signal recovery to less than 34% of the original sampling grid.

  5. Robustness of the filamentation instability in arbitrarily oriented magnetic field: Full three dimensional calculation

    Energy Technology Data Exchange (ETDEWEB)

    Bret, A., E-mail: antoineclaude.bret@uclm.es [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain and Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)

    2014-02-15

    The filamentation (Weibel) instability plays a key role in the formation of collisionless shocks which are thought to produce Gamma-Ray-Bursts and High-Energy-Cosmic-Rays in astrophysical environments. While it has been known for long that a flow-aligned magnetic field can completely quench the instability, it was recently proved in 2D that in the cold regime, such cancelation is possible if and only if the field is perfectly aligned. Here, this result is finally extended to a 3D geometry. Calculations are conducted for symmetric and asymmetric counter-streaming relativistic plasma shells. 2D results are retrieved in 3D: the instability can never be completely canceled for an oblique magnetic field. In addition, the maximum growth-rate is always larger for wave vectors lying in the plan defined by the flow and the oblique field. On the one hand, this bears consequences on the orientation of the generated filaments. On the other hand, it certifies 2D simulations of the problem can be performed without missing the most unstable filamentation modes.

  6. Full-vector geomagnetic field records from the East Eifel, Germany

    NARCIS (Netherlands)

    Monster, Marilyn W.L.; Langemeijer, Jaap; Wiarda, Laura R.; Dekkers, Mark J.; Biggin, Andy J.; Hurst, Elliot A.; de Groot, Lennart V.

    To create meaningful models of the geomagnetic field, high-quality directional and intensity input data are needed. However, while it is fairly straightforward to obtain directional data, intensity data are much scarcer, especially for periods before the Holocene. Here, we present data from twelve

  7. Optimization of Technique Factors for full-Field Digital Mammography and Comparison of Optimized Techniques to Screen-Film Mammography

    National Research Council Canada - National Science Library

    Berns, Eric

    2002-01-01

    The technical objectives of this study are to determine optimum techniques for a flat-panel Cesium- iodide silicon-diode full-field digital mammography system and to compare those optimized techniques...

  8. Optimization of Technique Factors for Full-Field Digital Mammography and Comparison of Optimized Techniques to Screen-Film Mammography

    National Research Council Canada - National Science Library

    Berns, Eric

    2001-01-01

    The technical objectives of this study are to determine optimum techniques for a flat-panel Cesium-iodide silicon-diode full-field digital mammography system and to compare those optimized techniques...

  9. Gyrokinetic full f analysis of electric field dynamics and poloidal velocity in the FT2-tokamak configuration

    International Nuclear Information System (INIS)

    Leerink, S.; Heikkinen, J. A.; Janhunen, S. J.; Kiviniemi, T. P.; Nora, M.; Ogando, F.

    2008-01-01

    The ELMFIRE gyrokinetic simulation code has been used to perform full f simulations of the FT-2 tokamak. The dynamics of the radial electric field and the creation of poloidal velocity in the presence of turbulence are presented.

  10. 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 ...

  11. Cross-phase modulational instability in an elliptical birefringent fiber ...

    Indian Academy of Sciences (India)

    birefringent fiber with higher order nonlinearity and dispersion ... order dispersion and nonlinear terms. Keywords. Cross-phase modulational instability; normal dispersion; group velocity mismatch; bire- fringent optical fiber. PACS Nos ...... Figure 13. Compares the gain spectrum obtained in case (iii) (dotted line) with that of.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    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...

  13. Intermediate strain rate testing methodologies and full-field optical strain measurement techniques for composite materials characterisation

    OpenAIRE

    Longana, M.L.

    2014-01-01

    Two optical full-field strain measurement techniques, Digital Image Correlation and the Grid Method, are applied to characterise the strain-rate dependent constitutive behaviour of composite materials. Optical strain measurement techniques based on full-field images are well established for material characterisation in the quasi-static strain rate region, however in this work they are developed to study the material behaviour at intermediate strain rates, which is relatively unexplored. For t...

  14. Full-field initialized decadal predictions with the MPI earth system model: an initial shock in the North Atlantic

    Science.gov (United States)

    Kröger, Jürgen; Pohlmann, Holger; Sienz, Frank; Marotzke, Jochem; Baehr, Johanna; Köhl, Armin; Modali, Kameswarrao; Polkova, Iuliia; Stammer, Detlef; Vamborg, Freja S. E.; Müller, Wolfgang A.

    2017-12-01

    Our decadal climate prediction system, which is based on the Max-Planck-Institute Earth System Model, is initialized from a coupled assimilation run that utilizes nudging to selected state parameters from reanalyses. We apply full-field nudging in the atmosphere and either full-field or anomaly nudging in the ocean. Full fields from two different ocean reanalyses are considered. This comparison of initialization strategies focuses on the North Atlantic Subpolar Gyre (SPG) region, where the transition from anomaly to full-field nudging reveals large differences in prediction skill for sea surface temperature and ocean heat content (OHC). We show that nudging of temperature and salinity in the ocean modifies OHC and also induces changes in mass and heat transports associated with the ocean flow. In the SPG region, the assimilated OHC signal resembles well OHC from observations, regardless of using full fields or anomalies. The resulting ocean transport, on the other hand, reveals considerable differences between full-field and anomaly nudging. In all assimilation runs, ocean heat transport together with net heat exchange at the surface does not correspond to OHC tendencies, the SPG heat budget is not closed. Discrepancies in the budget in the cases of full-field nudging exceed those in the case of anomaly nudging by a factor of 2-3. The nudging-induced changes in ocean transport continue to be present in the free running hindcasts for up to 5 years, a clear expression of memory in our coupled system. In hindcast mode, on annual to inter-annual scales, ocean heat transport is the dominant driver of SPG OHC. Thus, we ascribe a significant reduction in OHC prediction skill when using full-field instead of anomaly initialization to an initialization shock resulting from the poor initialization of the ocean flow.

  15. Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by interferometric signals temporal analysis

    OpenAIRE

    Apelian, Clement; Harms, Fabrice; Thouvenin, Olivier; Boccara, A. Claude

    2016-01-01

    We developed a new endogenous approach to reveal subcellular metabolic contrast in fresh ex vivo tissues taking advantage of the time dependence of the full field optical coherence tomography interferometric signals. This method reveals signals linked with local activity of the endogenous scattering elements which can reveal cells where other OCT-based techniques fail or need exogenous contrast agents. We benefit from the micrometric transverse resolution of full field OCT to image intracellu...

  16. Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by temporal analysis of interferometric signals

    OpenAIRE

    Apelian, Clement; Harms, Fabrice; Thouvenin, Olivier; Boccara, A. Claude

    2016-01-01

    We developed a new endogenous approach to reveal subcellular metabolic contrast in fresh ex vivo tissues taking advantage of the time dependence of the full field optical coherence tomography interferometric signals. This method reveals signals linked with local activity of the endogenous scattering elements which can reveal cells where other imaging techniques fail or need exogenous contrast agents. We benefit from the micrometric transverse resolution of full field OCT to image intracellula...

  17. 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......−5 profoundly affects the SC generation in a DFDD-ANDi photonic crystal fiber. Conventional simulations based on the scalar generalized nonlinear Schrödinger equation (GNLSE) fail to reproduce the prominent observed features of the SC generation in a short piece (9-cm) of this fiber. However, these features can...... be qualitatively or semi-quantitatively understood by the coupled GNLSE that takes into account the form-birefringence. The nonlinear polarization effects induced by the birefringence significantly distort the otherwise simple spectrotemporal field of the SC pulses. We therefore propose the fabrication...

  18. A Fibre Bragg Grating Interrogation Technique Based on High Birefringence Fibre Loop Mirror and WDM

    Directory of Open Access Journals (Sweden)

    Zhang Xun

    2016-01-01

    Full Text Available In this paper, a fibre Bragg grating (FBG interrogation technique based on high Birefringence fibre loop mirror (Hi-Bi FLM and wavelength division multiplexer (WDM is proposed and demonstrated. The approximate linear edge of the transmittance of the Hi-Bi FLM, which is a sinusoidal function of wavelength, is used to interrogate the sensing FBGs and WDMs is used to realize wavelength discrimination .Suitable for both static and dynamic sensing, this interrogation method has the advantages of all fibre design and high stability.

  19. 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.

  20. Full-vector geomagnetic field records from the East Eifel, Germany

    Science.gov (United States)

    Monster, Marilyn W. L.; Langemeijer, Jaap; Wiarda, Laura R.; Dekkers, Mark J.; Biggin, Andy J.; Hurst, Elliot A.; Groot, Lennart V. de

    2018-01-01

    To create meaningful models of the geomagnetic field, high-quality directional and intensity input data are needed. However, while it is fairly straightforward to obtain directional data, intensity data are much scarcer, especially for periods before the Holocene. Here, we present data from twelve flows (age range ∼ 200 to ∼ 470 ka) in the East Eifel volcanic field (Germany). These sites had been previously studied and are resampled to further test the recently proposed multi-method palaeointensity approach. Samples are first subjected to classic palaeomagnetic and rock magnetic analyses to optimise the subsequent palaeointensity experiments. Four different palaeointensity methods - IZZI-Thellier, the multispecimen method, calibrated pseudo-Thellier, and microwave-Thellier - are being used in the present study. The latter should be considered as supportive because only one or two specimens per site could be processed. Palaeointensities obtained for ten sites pass our selection criteria: two sites are successful with a single approach, four sites with two approaches, three more sites work with three approaches, and one site with all four approaches. Site-averaged intensity values typically range between 30 and 35 μT. No typically low palaeointensity values are found, in line with paleodirectional results which are compatible with regular palaeosecular variation of the Earth's magnetic field. Results from different methods are remarkably consistent and generally agree well with the values previously reported. They appear to be below the average for the Brunhes chron; there are no indications for relatively higher palaeointensities for units younger than 300 ka. However, our young sites could be close in age, and therefore may not represent the average intensity of the paleofield. Three of our sites are even considered coeval; encouragingly, these do yield the same palaeointensity within uncertainty bounds.

  1. Full adaptive backstepping design of a Speed Sensorless Field Oriented Controller for an Induction Motor

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    2001-01-01

    It is well known that modern induction motor control rely on a good dynamic model of the motor. Full state variable information together with exact parameter knowledge is needed. The aim of this work is to fulfill these needs by use of a novel nonlinear observer structure based on the backstepping...

  2. Refined OPLS all-atom force field for saturated phosphatidylcholine bilayers at full hydration.

    Science.gov (United States)

    Maciejewski, Arkadiusz; Pasenkiewicz-Gierula, Marta; Cramariuc, Oana; Vattulainen, Ilpo; Rog, Tomasz

    2014-05-01

    We report parametrization of dipalmitoyl-phosphatidylcholine (DPPC) in the framework of the Optimized Parameters for Liquid Simulations all-atom (OPLS-AA) force field. We chose DPPC as it is one of the most studied phospholipid species and thus has plenty of experimental data necessary for model validation, and it is also one of the highly important and abundant lipid types, e.g., in lung surfactant. Overall, PCs have not been previously parametrized in the OPLS-AA force field; thus, there is a need to derive its bonding and nonbonding parameters for both the polar and nonpolar parts of the molecule. In the present study, we determined the parameters for torsion angles in the phosphatidylcholine and glycerol moieties and in the acyl chains, as well the partial atomic charges. In these calculations, we used three methods: (1) Hartree-Fock (HF), (2) second order Møller-Plesset perturbation theory (MP2), and (3) density functional theory (DFT). We also tested the effect of the polar environment by using the polarizable continuum model (PCM), and for acyl chains the van der Waals parameters were also adjusted. In effect, six parameter sets were generated and tested on a DPPC bilayer. Out of these six sets, only one was found to be able to satisfactorily reproduce experimental data for the lipid bilayer. The successful DPPC model was obtained from MP2 calculations in an implicit polar environment (PCM).

  3. Assessment of a dynamic reference material for calibration of full-field measurement systems

    Science.gov (United States)

    Hack, Erwin; Feligiotti, Mara; Davighi, Andrea; Whelan, Maurice; Wang, Weizhuo V.; Patterson, Eann A.

    2012-10-01

    For holography and speckle interferometry the calibration of the sensitivity is a must, because illumination and observation directions vary across the field of view. A numerical estimate or a static calibration using rigid body motions is standard, and reference materials exist for static strain calibration. Recently, reference materials for the dynamic calibration of optical instruments of displacement and strain measurement were designed and prototypes were manufactured in the European FP7 project ADVISE. We review the properties of the reference material and the concept of traceability for the field of displacement values by using a calibrated single point transducer. The mode shape is assessed using out-of-plane DSPI, Finite Element Analysis as well as analytic solutions of the plate vibration. We present measurements using stroboscopic DSPI on the reference material under acoustic excitation and compare the measured mode shapes to the ones predicted by FE analysis. We apply different comparison methodologies based on point-by-point deviations and on decomposition of the mode shapes into a set of orthogonal basis functions. The latter method is well suited to assess stability and reproducibility of a mode shape. Finally, the deviations are used to estimate the reference material uncertainty which is an essential parameter for determining the calibration uncertainty. Uncertainty contributions of the DSPI set-up are taken into account. To conclude, the application area and limitations of the reference material are discussed.

  4. A method for the real-time construction of a full parallax light field

    Science.gov (United States)

    Tanaka, Kenji; Aoki, Soko

    2006-02-01

    We designed and implemented a light field acquisition and reproduction system for dynamic objects called LiveDimension, which serves as a 3D live video system for multiple viewers. The acquisition unit consists of circularly arranged NTSC cameras surrounding an object. The display consists of circularly arranged projectors and a rotating screen. The projectors are constantly projecting images captured by the corresponding cameras onto the screen. The screen rotates around an in-plane vertical axis at a sufficient speed so that it faces each of the projectors in sequence. Since the Lambertian surfaces of the screens are covered by light-collimating plastic films with vertical louver patterns that are used for the selection of appropriate light rays, viewers can only observe images from a projector located in the same direction as the viewer. Thus, the dynamic view of an object is dependent on the viewer's head position. We evaluated the system by projecting both objects and human figures and confirmed that the entire system can reproduce light fields with a horizontal parallax to display video sequences of 430x770 pixels at a frame rate of 45 fps. Applications of this system include product design reviews, sales promotion, art exhibits, fashion shows, and sports training with form checking.

  5. The constitutive compatibility method for identification of material parameters based on full-field measurements

    KAUST Repository

    Moussawi, Ali

    2013-10-01

    We revisit here the concept of the constitutive relation error for the identification of elastic material parameters based on image correlation. An additional concept, so called constitutive compatibility of stress, is introduced defining a subspace of the classical space of statically admissible stresses. The key idea is to define stresses as compatible with the observed deformation field through the chosen class of constitutive equation. This makes possible the uncoupling of the identification of stress from the identification of the material parameters. As a result, the global cost of the identification is strongly reduced. This uncoupling also leads to parametrized solutions in cases where the solution is non-unique as demonstrated on 2D numerical examples. © 2013 Elsevier B.V.

  6. Full-Vector Geomagnetic Field Records for the Late Quaternary from El Hierro and the Eifel

    Science.gov (United States)

    Monster, M.; de Groot, L. V.; Dekkers, M. J.; van Galen, J. P.; Kuiper, K.; Langemeijer, J.; Wiarda, L. R.

    2015-12-01

    Twenty-eight flows in the age range of c. 100 to c. 500 ka were sampled on the island of El Hierro (Canary Islands, Spain) and twelve in the Eifel (Germany). All sites from the Eifel had been previously dated, whereas the ages of the El Hierro flows were approximated by stratigraphic and directional coherency with a dated section c. 4 km to the north-east. Additionally, seven flows were dated using the ThermoFisher Helix multi-collector mass spectrometer at VU University Amsterdam (the Netherlands). The rocks were subjected to standard rock magnetic and palaeomagnetic experiments. Palaeodirections were obtained using both thermal and alternating-field demagnetisation techniques. Apart from two sites that appear to have been struck by lightning, all sites yielded reliable palaeodirections. Absolute palaeointensities were obtained using three different methods: IZZI-Thellier, the multispecimen protocol and the calibrated pseudo-Thellier technique. Nineteen sites from El Hierro and all twelve sites from the Eifel passed the selection criteria for one or more of these methods, with the pseudo-Thellier technique having the highest success rate (c. 35% for El Hierro and 55% for the Eifel). The palaeointensities obtained for El Hierro were mostly between 20 and 40 μT and for the Eifel between 20 and 50 μT, both with a tendency to be somewhat low compared to the present-day field of c. 39 μT and c. 49 μT, respectively. The pseudo-Thellier and multispecimen methods generally yielded lower palaeointensities than IZZI-Thellier, but no clear trend was visible.

  7. 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.

  8. Seasonal variations of microbial community in a full scale oil field produced water treatment plant

    Directory of Open Access Journals (Sweden)

    Q. Xie

    2016-01-01

    Full Text Available This study investigated the microbial community in a full scale anaerobic baffled reactor and sequencing batch reactor system for oil-produced water treatment in summer and winter. The community structures of fungi and bacteria were analyzed through polymerase chain reaction–denaturing gradient gel electrophoresis and Illumina high-throughput sequencing, respectively. Chemical oxygen demand effluent concentration achieved lower than 50 mg/L level after the system in both summer and winter, however, chemical oxygen demand removal rates after anaerobic baffled reactor treatment system were significant higher in summer than that in winter, which conformed to the microbial community diversity. Saccharomycotina, Fusarium, and Aspergillus were detected in both anaerobic baffled reactor and sequencing batch reactor during summer and winter. The fungal communities in anaerobic baffled reactor and sequencing batch reactor were shaped by seasons and treatment units, while there was no correlation between abundance of fungi and chemical oxygen demand removal rates. Compared to summer, the total amount of the dominant hydrocarbon degrading bacteria decreased by 10.2% in anaerobic baffled reactor, resulting in only around 23% of chemical oxygen demand was removed in winter. Although microbial community significantly varied in the three parallel sulfide reducing bacteria, the performance of these bioreactors had no significant difference between summer and winter.

  9. Shear behavior of steel fiber reinforced concrete using full-field displacements from digital image correlation

    Directory of Open Access Journals (Sweden)

    Gali Sahith

    2017-01-01

    Full Text Available Reinforced concrete beams with discrete hooked-end steel fibers at 0.5% volume fraction are tested with a shear span to depth (a/d ratio equal to 1.8. Digital image correlation (DIC technique was used to obtain the full-filed displacements from the beam. The formation and propagation of a shear crack which directly influences the load response and the peak load in the load response of the beam is monitored using the displacement information available from DIC. There is a continuous increase in slip across the crack faces with increasing load, which produces an increase in the crack opening. The dilatant behavior indicated by the proportion of crack opening to slip displacement obtained from the control and the SFRC beams is identical. Failure in control beams is brittle and was produced by the opening of dominant shear crack within the shear span. At the peak load, the shear crack pattern in fiber reinforced concrete is identical to the crack pattern in the control beam. The fiber reinforced concrete beams exhibit post peak load carrying capacity with continued slip of the dominant shear crack. The crack bridging stress provided by the fibers results in a significant increase shear transfer across the crack which provides significant post-peak load carrying capacity with increasing slip of the shear crack.

  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. High frequency magnetic field technique: mathematical modelling and development of a full scale water fraction meter

    Energy Technology Data Exchange (ETDEWEB)

    Cimpan, Emil

    2004-09-15

    This work is concerned with the development of a new on-line measuring technique to be used in measurements of the water concentration in a two component oil/water or three component (i.e. multiphase) oil/water/gas flow. The technique is based on using non-intrusive coil detectors and experiments were performed both statically (medium at rest) and dynamically (medium flowing through a flow rig). The various coil detectors were constructed with either one or two coils and specially designed electronics were used. The medium was composed by air, machine oil, and water having different conductivity values, i.e. seawater and salt water with various conductivities (salt concentrations) such as 1 S/m, 4.9 S/m and 9.3 S/m. The experimental measurements done with the different mixtures were further used to mathematically model the physical principle used in the technique. This new technique is based on measuring the coil impedance and signal frequency at the self-resonance frequency of the coil to determine the water concentration in the mix. By using numerous coils it was found, experimentally, that generally both the coil impedance and the self-resonance frequency of the coil decreased as the medium conductivity increased. Both the impedance and the self-resonance frequency of the coil depended on the medium loss due to the induced eddy currents within the conductive media in the mixture, i.e. water. In order to detect relatively low values of the medium loss, the self-resonance frequency of the coil and also of the magnetic field penetrating the media should be relatively high (within the MHz range and higher). Therefore, the technique was called and referred to throughout the entire work as the high frequency magnetic field technique (HFMFT). To practically use the HFMFT, it was necessary to circumscribe an analytical frame to this technique. This was done by working out a mathematical model that relates the impedance and the self-resonance frequency of the coil to the

  12. Dynamic full field optical coherence tomography: subcellular metabolic contrast revealed in tissues by interferometric signals temporal analysis.

    Science.gov (United States)

    Apelian, Clement; Harms, Fabrice; Thouvenin, Olivier; Boccara, A Claude

    2016-04-01

    We developed a new endogenous approach to reveal subcellular metabolic contrast in fresh ex vivo tissues taking advantage of the time dependence of the full field optical coherence tomography interferometric signals. This method reveals signals linked with local activity of the endogenous scattering elements which can reveal cells where other OCT-based techniques fail or need exogenous contrast agents. We benefit from the micrometric transverse resolution of full field OCT to image intracellular features. We used this time dependence to identify different dynamics at the millisecond scale on a wide range of organs in normal or pathological conditions.

  13. Hough transform for clustered microcalcifications detection in full-field digital mammograms

    Science.gov (United States)

    Fanizzi, A.; Basile, T. M. A.; Losurdo, L.; Amoroso, N.; Bellotti, R.; Bottigli, U.; Dentamaro, R.; Didonna, V.; Fausto, A.; Massafra, R.; Moschetta, M.; Tamborra, P.; Tangaro, S.; La Forgia, D.

    2017-09-01

    Many screening programs use mammography as principal diagnostic tool for detecting breast cancer at a very early stage. Despite the efficacy of the mammograms in highlighting breast diseases, the detection of some lesions is still doubtless for radiologists. In particular, the extremely minute and elongated salt-like particles of microcalcifications are sometimes no larger than 0.1 mm and represent approximately half of all cancer detected by means of mammograms. Hence the need for automatic tools able to support radiologists in their work. Here, we propose a computer assisted diagnostic tool to support radiologists in identifying microcalcifications in full (native) digital mammographic images. The proposed CAD system consists of a pre-processing step, that improves contrast and reduces noise by applying Sobel edge detection algorithm and Gaussian filter, followed by a microcalcification detection step performed by exploiting the circular Hough transform. The procedure performance was tested on 200 images coming from the Breast Cancer Digital Repository (BCDR), a publicly available database. The automatically detected clusters of microcalcifications were evaluated by skilled radiologists which asses the validity of the correctly identified regions of interest as well as the system error in case of missed clustered microcalcifications. The system performance was evaluated in terms of Sensitivity and False Positives per images (FPi) rate resulting comparable to the state-of-art approaches. The proposed model was able to accurately predict the microcalcification clusters obtaining performances (sensibility = 91.78% and FPi rate = 3.99) which favorably compare to other state-of-the-art approaches.

  14. Full-field electroretinogram recorded with skin electrodes in normal adults

    Directory of Open Access Journals (Sweden)

    Arthur Gustavo Fernandes

    Full Text Available ABSTRACT Purpose: Alternative recording methods have been tested to allow the electroretinogram (ERG recording in uncooperative patients and/or patients with palpebral alterations, including recordings with skin electrodes. The purpose of this study was to compare ERG recorded with skin electrodes and well-established microfiber electrodes and to determine normative values of ERG parameters for recording with skin electrodes. Methods: Fifty healthy volunteers (17-26 years; mean 20.63 ± 2.01 years participated in the study. A gold disk skin electrode was placed on the lower orbital rim of a randomly chosen eye. On the contralateral eye, a microfiber electrode was positioned in the lower conjunctival sac. Gold disc electrodes were positioned at the ipsilateral outer canthus of both eyes acting as reference electrodes for the creation of a potential difference. Two ground electrodes were placed on the lobe of each ear. ERGs were recorded according to the International Society of Clinical Electrophysiology Visual (ISCEV protocol using the VERIS 5.1.9 system for data acquisition and analysis. Results: Both types of electrodes showed similar wave response morphologies. The implicit time of responses between the two electrodes was comparable. On peak-to-peak amplitude, skin electrode recordings showed an amplitude reduction of 61.4% for rod responses, 61.5% for maximal responses, 46.2% for oscillatory potentials, 57.4% for cone responses, and 54.4% for 30Hz-flicker responses, when compared with microfiber electrode recordings. Based on these findings, normative values for peak-to-peak amplitude and implicit time to be used as a reference for ERGs recorded with skin electrodes were determined. Conclusions: ERGs recorded with skin electrodes presented lower peak-to-peak amplitude compared with microfiber electrodes. However, using appropriate normative values, skin electrodes may be useful for specific target populations such as uncooperative infants

  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. Spinning wave plate design for retinal birefringence scanning

    Science.gov (United States)

    Irsch, K.; Gramatikov, B. I.; Wu, Y.-K.; Guyton, D. L.

    2009-02-01

    To enhance foveal fixation detection while bypassing the deleterious effects of corneal birefringence in retinal birefringence scanning (RBS), we developed a new RBS design introducing a double-pass spinning half wave plate (HWP) and a fixed double-pass retarder into the optical system. Utilizing the measured corneal birefringence from a data set of 300 human eyes, an algorithm and a related computer program, based on Mueller-Stokes matrix calculus, were developed in MATLAB for optimizing the properties of both wave plates. Foveal fixation detection was optimized with the HWP spun 9/16 as fast as the circular scan, with the fixed retarder having a retardance of 45° and fast axis at 90°. With this new RBS design, a significant statistical improvement of 7.3 times in signal strength, i.e. FFT power, was achieved for the available data set compared with the previous RBS design. The computer-model-optimized RBS design has the potential not only for eye alignment screening, but also for remote fixation sensing and eye tracking applications.

  17. Eigenmodes of spin vertical-cavity surface-emitting lasers with local linear birefringence and gain dichroism

    Science.gov (United States)

    Fördös, T.; Jaffrès, H.; Postava, K.; Seghilani, M. S.; Garnache, A.; Pištora, J.; Drouhin, H. J.

    2017-10-01

    We present a general method for the modeling of semiconductor lasers such as a vertical-cavity surface-emitting laser and a vertical-external-cavity surface-emitting laser containing multiple quantum wells and involving anisotropies that may reveal (i) a local linear birefringence due to the strain field at the surface or (ii) a birefringence in quantum wells due to phase amplitude coupling originating from the reduction of the biaxial D2 d symmetry group to the C2 v symmetry group at the III-V ternary semiconductor interfaces. From a numerical point of view, a scattering S-matrix recursive method is implemented using a gain or amplification tensor derived analytically from the Maxwell-Bloch equations. It enables one to model the properties of the emission (threshold, polarization, and mode splitting) from the laser with multiple quantum well active zones by searching for the resonant eigenmodes of the cavity. The method is demonstrated on real laser structures and is presently used for the extraction of optical permittivity tensors of surface strain and quantum wells in agreement with experiments. The method can be generalized to find the laser eigenmodes in the most general case of circular polarized pumps (unbalance between the spin-up and spin-down channels) and/or dichroism allowing an elliptically polarized light emission as recently demonstrated experimentally when the linear birefringence is almost compensated [Joly et al., Opt. Lett. 42, 651 (2017), 10.1364/OL.42.000651].

  18. The Research on Full-speed Field Weakening Control Method of Electric Vehicle Interior Permanent Magnet Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Gao Run-Ze

    2017-01-01

    Full Text Available The motor drive system represents a key technology for development of the electrical vehicles, and the permanent magnet synchronous motor becomes the mainstream of the new energy vehicle drive motor for the superior performances in power density, low-speed torque density, efficiency and reliability. The paper studies the field weakening control strategy for the interior permanent magnet synchronous motor (IPMSM and provides a field weakening control strategy for the IPMSM at the full-speed range. By studying the mathematical IPMSM model and the methods of conventional vector control and analyzing the operating conditions of the IPMSM at the full-speed range, the paper divides the operating conditions into constant torque operation region I, constant torque operation region II, constant power field weakening operation region and high-speed field weakening operation region to confirm the control strategy algorithm in each region and the transition conditions between regions and provide the current control strategy that the d-axis current and q-axis current are confirmed by the reference torque and the feedback speed. Modeling of the field weakening control strategies in each region is made through the Matlab/Simulink, and simulation of the operating conditions with a steady-state load and a dynamic load is done to verify that the field weakening control strategy in each region is feasible. A co-simulation is made by combining the Matlab/Simulink-based control model, the RecurDyn-based virtual prototype and the RT-LAB to verify the feasible field weakening control strategy.

  19. 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...

  20. Code for three dimensional analysis of thermal birefringence in solid-state lasers

    International Nuclear Information System (INIS)

    Furukawa, Hiroyuki; Yamanaka, Chiyoe; Hiura, Norimitsu; Matsui, Hiroki; Yoshida, Takuji; Kiriyama, Hiromitsu; Yamanaka, Masanobu; Izawa, Yasukazu; Nakai, Sadao

    1999-01-01

    A three dimensional (3D) analysis code of thermal birefringence in solid-state lasers was developed. Basic equations include thermal conduction, absorption of laser energy, thermal stress and thermal birefringence. Relative phase shifts induced by thermal effects measured and obtained by simulation are in good agreement with quantitatively. Edge effects of thermal birefringence are quantitatively estimated by 3D simulation. Those are unable to be estimated by 2D analysis. (author)

  1. Assistance in MSD Research and Development: Part 2, Full scale field testing at mining operations: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Worsey, P.N.; Canon, C.

    1988-06-01

    Full scale and field testing of a simple mechanical stemming aid is described. The aid comprises a solid unit placed in the stemming above the explosive column and is designed to improve blasting efficiency and reduce drilling and blasting costs. It is designed to work with back filled drill cuttings or any other suitable stemming material. The results of Phase I testing were highly successful, indicating that the stemming aid has technically an extremely good chance of success at full scale when constructed of low cost materials. Phase II of the stemming aid research and development program comprised of the testing of various forms of the stemming is at full scale in non-research oriented i.e. field settings. The stemming aid was field tested at 4 different sites for a variety of mining application: First in underground workings at the UMR experimental mine in one and three quarter inch diameter horizontal blast holes incorporated into full blast patterns; three and three and a half inch blast holes at two crushed rock/limestone quarries in the Rolla area and at a surface coal mine operation run by Peabody Coal Company at Lynnville, Indiana in which nine and seven eighths, ten and five eighths and fifteen and a quarter inch diameter blast holes were used for parting and overburden removal. 2 refs., 37 figs., 11 tabs.

  2. Screen-film versus full-field digital mammography: Radiation dose and image quality in a large teaching hospital

    Directory of Open Access Journals (Sweden)

    Stantić Tomislav J.

    2013-01-01

    Full Text Available The objective of this paper is to measure the radiation dose and image quality in conventional screen-film mammography and full-field digital mammography in women referred to mammography examination. Participants underwent bilateral, two-view screen-film mammography or full-field digital mammography. The visibility of anatomical regions and overall clinical image quality was rated by experienced radiologists. Total of 387 women and 1548 mammograms were enrolled in the study. Image quality was assessed in terms of image quality score, whereas patient dose assessment was performed in terms of mean glandular dose. Average mean glandular dose for cranio-caudal projection was 1.5 mGy and 2.1 mGy in full-field digital mammography and screen-film mammography, respectively. For medio-lateral oblique projection, corresponding values were 2.3 and 2.1 mGy. Overall image quality criteria scoring was 0.82 and 0.99 for screen-film and digital systems, respectively. The scores were in the range from 0.11 to 1.0 for different anatomical structures. Overall, full-field digital mammography was superior both in terms of image quality and dose over the screen-film mammography. The results have indicated that phantom dose values can assist in setting the optimisation activities in mammography and for comparison between mammography units. To obtain accurate diagnostic information with an acceptable radiation dose to breast, it is necessary to periodically perform patient dose and image quality surveys in all mammography units.

  3. Study of Collagen Birefringence in Different Grades of Oral Squamous Cell Carcinoma Using Picrosirius Red and Polarized Light Microscopy

    Directory of Open Access Journals (Sweden)

    Pillai Arun Gopinathan

    2015-01-01

    Full Text Available Objectives. The present study was done to evaluate birefringence pattern of collagen fibres in different grades of oral squamous cell carcinoma using Picrosirius red stain and polarization microscopy and to determine if there is a change in collagen fibres between different grades of oral squamous cell carcinoma. Materials and Methods. Picrosirius red stained 5 μm thick sections of previously diagnosed different grades of squamous cell carcinoma and normal oral mucosa were studied under polarization microscopy for arrangement as well as birefringence of collagen fibres around tumour islands. Results. It was found that thin collagen fibres increased and thick collagen fibres decreased with dedifferentiation of OSCC (P<0.0001 . It was observed that there was change in polarization colours of thick fibres from yellowish orange to greenish yellow with dedifferentiation of OSCC indicating loosely packed fibres (P<0.0001. Conclusion. There was a gradual change of birefringence of collagen from yellowish orange to greenish yellow from well to poorly differentiated squamous cell carcinoma, indicating that there is a change from mature form of collagen to immature form as tumour progresses. Studying collagen fibres with Picrosirius red for stromal changes around tumour islands along with routine staining may help in predicting the prognosis of tumour.

  4. Full-Wave Analysis of Traveling-Wave Field-Effect Transistors Using Finite-Difference Time-Domain Method

    Directory of Open Access Journals (Sweden)

    Koichi Narahara

    2012-01-01

    Full Text Available Nonlinear transmission lines, which define transmission lines periodically loaded with nonlinear devices such as varactors, diodes, and transistors, are modeled in the framework of finite-difference time-domain (FDTD method. Originally, some root-finding routine is needed to evaluate the contributions of nonlinear device currents appropriately to the temporally advanced electrical fields. Arbitrary nonlinear transmission lines contain large amount of nonlinear devices; therefore, it costs too much time to complete calculations. To reduce the calculation time, we recently developed a simple model of diodes to eliminate root-finding routines in an FDTD solver. Approximating the diode current-voltage relation by a piecewise-linear function, an extended Ampere's law is solved in a closed form for the time-advanced electrical fields. In this paper, we newly develop an FDTD model of field-effect transistors (FETs, together with several numerical examples that demonstrate pulse-shortening phenomena in a traveling-wave FET.

  5. Full-field fabric stress mapping by micro Raman spectroscopy in a yarn push-out test.

    Science.gov (United States)

    Lei, Z K; Qin, F Y; Fang, Q C; Bai, R X; Qiu, W; Chen, X

    2018-02-01

    The full-field stress distribution of a two-dimensional plain fabric was mapped using micro Raman spectroscopy (MRS) through a novel yarn push-out test, simulating a quasi-static projectile impact on the fabric. The stress-strain relationship for a single yarn was established using a digital image correlation method in a single-yarn tensile test. The relationship between Raman peak shift and aramid Kevlar 49 yarn stress was established using MRS in a single-yarn tensile test. An out-of-plane loading test was conducted on an aramid Kevlar 49 plain fabric, and the yarn stress was measured using MRS. From the full-field fabric stress distribution, it can be observed that there is a cross-shaped distribution of high yarn stress; this result would be helpful in further studies on load transfer on a fabric during a projectile impact.

  6. Full-field vibration measurements of the violin using digital stroboscopic holographic interferometry and electromagnetic stimulation of the strings

    Science.gov (United States)

    Keersmaekers, Lissa; Keustermans, William; De Greef, Daniël; Dirckx, Joris J. J.

    2016-06-01

    We developed a setup in which the strings of the violin are driven electromagnetically, and the resulting vibration of the instrument is measured with digital stroboscopic holography. A 250mW single mode green laser beam is chopped using an acousto-optic modulator, generating illumination pulses of 2% of the vibration period. The phase of the illumination pulse is controlled by a programmable function generator so that digital holograms can be recorded on a number of subsequent time positions within the vibration phase. From these recordings, the out of plane motion as a function of time is reconstructed in full field. We show results of full-field vibration amplitude and vibration phase maps, and time resolved full-field deformations of the violin back plane. Time resolved measurements show in detail how the deformation of the violin plane changes as a function of time at different frequencies. We found very different behavior under acoustic stimulation of the instrument and when using electromagnetic stimulation of a string. The aim of the work it to gather data which can be used in power flow calculations to study how the energy of the strings is conducted to the body of the violin and eventually is radiated as sound.

  7. Full-field vibration measurements of the violin using digital stroboscopic holographic interferometry and electromagnetic stimulation of the strings

    Energy Technology Data Exchange (ETDEWEB)

    Keersmaekers, Lissa; Keustermans, William, E-mail: william.keustermans@uantwerpen.be; De Greef, Daniël; Dirckx, Joris J. J. [University of Antwerp, Laboratory of Biophysics and Biomedical Physics, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

    2016-06-28

    We developed a setup in which the strings of the violin are driven electromagnetically, and the resulting vibration of the instrument is measured with digital stroboscopic holography. A 250 mW single mode green laser beam is chopped using an acousto-optic modulator, generating illumination pulses of 2% of the vibration period. The phase of the illumination pulse is controlled by a programmable function generator so that digital holograms can be recorded on a number of subsequent time positions within the vibration phase. From these recordings, the out of plane motion as a function of time is reconstructed in full field. We show results of full-field vibration amplitude and vibration phase maps, and time resolved full-field deformations of the violin back plane. Time resolved measurements show in detail how the deformation of the violin plane changes as a function of time at different frequencies. We found very different behavior under acoustic stimulation of the instrument and when using electromagnetic stimulation of a string. The aim of the work it to gather data which can be used in power flow calculations to study how the energy of the strings is conducted to the body of the violin and eventually is radiated as sound.

  8. Full-field vibration measurements of the violin using digital stroboscopic holographic interferometry and electromagnetic stimulation of the strings

    International Nuclear Information System (INIS)

    Keersmaekers, Lissa; Keustermans, William; De Greef, Daniël; Dirckx, Joris J. J.

    2016-01-01

    We developed a setup in which the strings of the violin are driven electromagnetically, and the resulting vibration of the instrument is measured with digital stroboscopic holography. A 250 mW single mode green laser beam is chopped using an acousto-optic modulator, generating illumination pulses of 2% of the vibration period. The phase of the illumination pulse is controlled by a programmable function generator so that digital holograms can be recorded on a number of subsequent time positions within the vibration phase. From these recordings, the out of plane motion as a function of time is reconstructed in full field. We show results of full-field vibration amplitude and vibration phase maps, and time resolved full-field deformations of the violin back plane. Time resolved measurements show in detail how the deformation of the violin plane changes as a function of time at different frequencies. We found very different behavior under acoustic stimulation of the instrument and when using electromagnetic stimulation of a string. The aim of the work it to gather data which can be used in power flow calculations to study how the energy of the strings is conducted to the body of the violin and eventually is radiated as sound.

  9. Full spatial-field visualization of gas temperature in an air micro-glow discharge by calibrated Schlieren photography

    Science.gov (United States)

    Xiong, Qing; Xu, Le; Wang, Xia; Xiong, Lin; Huang, Qinghua; Chen, Qiang; Wang, Jingang; Peng, Wenxiong; Li, Jiarui

    2018-03-01

    Gas temperature is an important basic parameter for both fundamental research and applications of plasmas. In this work, efforts were made to visualize the full spatial field of gas temperature (T g) in a microdischarge with sharp T g gradients by a method of calibrated Schlieren (CS) photography. Compared to other two typical diagnostic approaches, optical emission spectroscopy (OES) and Rayleigh scattering, the proposed CS method exhibits the ability to capture the whole field of gas temperature using a single Schlieren image, even the discharge is of non-luminous zones like Faraday dark space (FDS). The image shows that the T g field in the studied micro-glow air discharge expands quickly with the increase of discharge currents, especially in the cathode region. The two-dimensional maps of gas temperature display a ‘W-shape’ with sharp gradients in both areas of negative and positive glows, slightly arched distributions in the positive column, and cooling zones in the FDS. The obtained T g fields show similar patterns to that of the discharge luminance. With an increase in discharge currents, more electric energy is dissipated by heating air gas and inducing constriction of the low-temperature FDS. Except in the vicinities of electrode boundaries, due to the interference from optical diffraction, the estimated gas temperature distributions are of acceptable accuracy, confirmed by the approaches of OES and UV Rayleigh scattering.

  10. ICRF full wave field solution and absorption for D-T and D-3He heating scenarios

    International Nuclear Information System (INIS)

    Scharer, J.; Sund, R.

    1989-01-01

    We consider a fundamental power conservation relation, full wave solutions for fields and power absorption in moderate and high density tokamaks to third order in the gyroradius expansion. The power absorption, conductivity tensor and kinetic flux associated with the conservation relation as well as the wave differential equation are obtained. Cases examined include D-T and D- 3 He scenarios for TFTR,JET and CIT at the Fundamental and Second harmonic. Optimum single pass absorption cases for D-T operation in JET and CIT are considered as a function of the K ≡ spectrum of the antenna with an without a minority He 3 resonance. It is found that at elevated temperatures >4 keV, minority (10%) fundamental deuterium absorption is very efficient for either fast wave low or high field incidence or high field Bernstein wave incidence. We consider the effects of a 10 keV bulk and 100 keV tail helium distribution on the second harmonic absorption in a deuterium plasma for Jet parameters. In addition, scenarios with ICRF operation without attendant substantial tritium concentrations are found the fundamental (15%) and second harmonic helium (33%) heating in a the deuterium plasma. For High field operation at high density in CIT, we find a higher part of the K parallel spectrum yields good single pass absorption with a 5% minority helium concentration in D-T

  11. Automated Detection of Ocular Alignment with Binocular Retinal Birefringence Scanning

    Science.gov (United States)

    Hunter, David G.; Shah, Ankoor S.; Sau, Soma; Nassif, Deborah; Guyton, David L.

    2003-06-01

    We previously developed a retinal birefringence scanning (RBS) device to detect eye fixation. The purpose of this study was to determine whether a new binocular RBS (BRBS) instrument can detect simultaneous fixation of both eyes. Control (nonmyopic and myopic) and strabismic subjects were studied by use of BRBS at a fixation distance of 45 cm. Binocularity (the percentage of measurements with bilateral fixation) was determined from the BRBS output. All nonstrabismic subjects with good quality signals had binocularity >75%. Binocularity averaged 5% in four subjects with strabismus (range of 0 -20%). BRBS may potentially be used to screen individuals for abnormal eye alignment.

  12. Full-Color LCD Microdisplay System Based on OLED Backlight Unit and Field-Sequential Color Driving Method

    Directory of Open Access Journals (Sweden)

    Sungho Woo

    2011-01-01

    Full Text Available We developed a single-panel LCD microdisplay system using a field-sequential color (FSC driving method and an organic light-emitting diode (OLED as a backlight unit (BLU. The 0.76′′ OLED BLU with red, green, and blue (RGB colors was fabricated by a conventional UV photolithography patterning process and by vacuum deposition of small molecule organic layers. The field-sequential driving frequency was set to 255 Hz to allow each of the RGB colors to be generated without color mixing at the given display frame rate. A prototype FSC LCD microdisplay system consisting of a 0.7′′ LCD microdisplay panel and the 0.76′′ OLED BLU successfully exhibited color display and moving picture images using the FSC driving method.

  13. Negative pressures in full-scale distribution system: field investigation, modelling, estimation of intrusion volumes and risk for public health

    Directory of Open Access Journals (Sweden)

    M. C. Besner

    2010-07-01

    Full Text Available Various investigations encompassing microbial characterization of external sources of contamination (soil and trenchwater surrounding water mains, flooded air-valve vaults, field pressure monitoring, and hydraulic and transient analyses were conducted in the same distribution system where two epidemiological studies showing an increase in gastrointestinal illness for people drinking tap water were conducted in the 1990's. Interesting results include the detection of microorganisms indicators of fecal contamination in all external sources investigated but at a higher frequency in the water from flooded air-valve vaults, and the recording of 18 negative pressure events in the distribution system during a 17-month monitoring period. Transient analysis of this large and complex distribution system was challenging and highlighted the need to consider field pressure data in the process.

  14. Holographic matched filter for full-field in-line signal processing of optical-fiber sensor outputs

    Science.gov (United States)

    Indebetouw, Guy; Bennett, Kim D.; Zhang, Pinyi; May, Russell G.

    1990-01-01

    A holographic matched filter is used to measure the changes in the output of a dual-mode fiber undergoing axial strain. The hologram is formed by interfering collimated light from a single-mode reference fiber and an unstrained dual-mode sensor fiber on a small piece of holographic material. When the hologram is illuminated by the strained sensor fiber, the cross-correlation field comparing the dual-mode output and its previous state, as recorded in the hologram, is collected, focused into a pick-up fiber, and sent to a photodiode. This arrangement allows for a compact, in-line method for full-field processing of the strain-induced changes in phase and amplitude in the sensor fiber. Other uses of such fiber-based correlators are suggested.

  15. Full-field modal analysis during base motion excitation using high-speed 3D digital image correlation

    Science.gov (United States)

    Molina-Viedma, Ángel J.; López-Alba, Elías; Felipe-Sesé, Luis; Díaz, Francisco A.

    2017-10-01

    In recent years, many efforts have been made to exploit full-field measurement optical techniques for modal identification. Three-dimensional digital image correlation using high-speed cameras has been extensively employed for this purpose. Modal identification algorithms are applied to process the frequency response functions (FRF), which relate the displacement response of the structure to the excitation force. However, one of the most common tests for modal analysis involves the base motion excitation of a structural element instead of force excitation. In this case, the relationship between response and excitation is typically based on displacements, which are known as transmissibility functions. In this study, a methodology for experimental modal analysis using high-speed 3D digital image correlation and base motion excitation tests is proposed. In particular, a cantilever beam was excited from its base with a random signal, using a clamped edge join. Full-field transmissibility functions were obtained through the beam and converted into FRF for proper identification, considering a single degree-of-freedom theoretical conversion. Subsequently, modal identification was performed using a circle-fit approach. The proposed methodology facilitates the management of the typically large amounts of data points involved in the DIC measurement during modal identification. Moreover, it was possible to determine the natural frequencies, damping ratios and full-field mode shapes without requiring any additional tests. Finally, the results were experimentally validated by comparing them with those obtained by employing traditional accelerometers, analytical models and finite element method analyses. The comparison was performed by using the quantitative indicator modal assurance criterion. The results showed a high level of correspondence, consolidating the proposed experimental methodology.

  16. Field Testing of a Wet FGD Additive for Enhanced Mercury Control - Task 3 Full-scale Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Gary Blythe

    2007-05-01

    This Topical Report summarizes progress on Cooperative Agreement DE-FC26-04NT42309, 'Field Testing of a Wet FGD Additive'. The objective of the project is to demonstrate the use of a flue gas desulfurization (FGD) additive, Degussa Corporation's TMT-15, to prevent the reemission of elemental mercury (Hg{sup 0}) in flue gas exiting wet FGD systems on coal-fired boilers. Furthermore, the project intends to demonstrate whether the additive can be used to precipitate most of the mercury (Hg) removed in the wet FGD system as a fine TMT salt that can be separated from the FGD liquor and bulk solid byproducts for separate disposal. The project is conducting pilot- and full-scale tests of the TMT-15 additive in wet FGD absorbers. The tests are intended to determine required additive dosages to prevent Hg{sup 0} reemissions and to separate mercury from the normal FGD byproducts for three coal types: Texas lignite/Power River Basin (PRB) coal blend, high-sulfur Eastern bituminous coal, and low-sulfur Eastern bituminous coal. The project team consists of URS Group, Inc., EPRI, TXU Generation Company LP, Southern Company, and Degussa Corporation. TXU Generation has provided the Texas lignite/PRB cofired test site for pilot FGD tests, Monticello Steam Electric Station Unit 3. Southern Company is providing the low-sulfur Eastern bituminous coal host site for wet scrubbing tests, as well as the pilot- and full-scale jet bubbling reactor (JBR) FGD systems to be tested. IPL, an AES company, provided the high-sulfur Eastern bituminous coal full-scale FGD test site and cost sharing. Degussa Corporation is providing the TMT-15 additive and technical support to the test program as cost sharing. The project is being conducted in six tasks. Of the six project tasks, Task 1 involves project planning and Task 6 involves management and reporting. The other four tasks involve field testing on FGD systems, either at pilot or full scale. The four tasks include: Task 2 - Pilot

  17. Strong modification of the reflection from birefringent layers of semiconductor nanowires by nanoshells

    NARCIS (Netherlands)

    Diedenhofen, S.L.; Algra, R.E.; Bakkers, E.P.A.M.; Gómez Rivas, J.

    2011-01-01

    The propagation of light in layers of vertically aligned nanowires is determined by their unique and extreme optical properties. Depending on the nanowire filling fraction and their diameter, layers of nanowires form strongly birefringent media. This large birefringence gives rise to sharp angle

  18. 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

  19. 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...

  20. Annealing of UV-Induced Birefringence in Hydrogen Loaded Germanosilicate Fibres

    DEFF Research Database (Denmark)

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

    2005-01-01

    UV-reduced birefringence in germanosilicate optical fibres loaded with hydrogen is annealed out at low temperatures (125o C). Annealing for induced birefringence in gratings written by either s or p polarised UV light are identical. The results are incosistent with previous models for the origin ...

  1. Achromatic and high-resolution full-field X-ray microscopy based on total-reflection mirrors.

    Science.gov (United States)

    Matsuyama, Satoshi; Emi, Yoji; Kino, Hidetoshi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2015-04-20

    We developed an achromatic and high-resolution full-field X-ray microscope based on advanced Kirkpatrick-Baez mirror optics that comprises two pairs of elliptical mirrors and hyperbolic mirrors utilizing the total reflection of X-rays. Performance tests to investigate the spatial resolution and chromatic aberration were performed at SPring-8. The microscope clearly resolved the pattern with ~100-nm feature size. Imaging the pattern by changing the X-ray energy revealed achromatism in the wide energy range of 8-11 keV.

  2. GOCO05c: A New Combined Gravity Field Model Based on Full Normal Equations and Regionally Varying Weighting

    Science.gov (United States)

    Fecher, T.; Pail, R.; Gruber, T.

    2017-05-01

    GOCO05c is a gravity field model computed as a combined solution of a satellite-only model and a global data set of gravity anomalies. It is resolved up to degree and order 720. It is the first model applying regionally varying weighting. Since this causes strong correlations among all gravity field parameters, the resulting full normal equation system with a size of 2 TB had to be solved rigorously by applying high-performance computing. GOCO05c is the first combined gravity field model independent of EGM2008 that contains GOCE data of the whole mission period. The performance of GOCO05c is externally validated by GNSS-levelling comparisons, orbit tests, and computation of the mean dynamic topography, achieving at least the quality of existing high-resolution models. Results show that the additional GOCE information is highly beneficial in insufficiently observed areas, and that due to the weighting scheme of individual data the spectral and spatial consistency of the model is significantly improved. Due to usage of fill-in data in specific regions, the model cannot be used for physical interpretations in these regions.

  3. Multi-kernel deconvolution for contrast improvement in a full field imaging system with engineered PSFs using conical diffraction

    Science.gov (United States)

    Enguita, Jose M.; Álvarez, Ignacio; González, Rafael C.; Cancelas, Jose A.

    2018-01-01

    The problem of restoration of a high-resolution image from several degraded versions of the same scene (deconvolution) has been receiving attention in the last years in fields such as optics and computer vision. Deconvolution methods are usually based on sets of images taken with small (sub-pixel) displacements or slightly different focus. Techniques based on sets of images obtained with different point-spread-functions (PSFs) engineered by an optical system are less popular and mostly restricted to microscopic systems, where a spot of light is projected onto the sample under investigation, which is then scanned point-by-point. In this paper, we use the effect of conical diffraction to shape the PSFs in a full-field macroscopic imaging system. We describe a series of simulations and real experiments that help to evaluate the possibilities of the system, showing the enhancement in image contrast even at frequencies that are strongly filtered by the lens transfer function or when sampling near the Nyquist frequency. Although results are preliminary and there is room to optimize the prototype, the idea shows promise to overcome the limitations of the image sensor technology in many fields, such as forensics, medical, satellite, or scientific imaging.

  4. Full field tomography using interference fringes casting of a non spatially-coherent extended spectrally modulated broadband light source

    Science.gov (United States)

    Arieli, Yoel; Epshtein, Shlomi; Harris, Alon; Yaacubov, Igor; Cohen, Yoel

    2018-01-01

    A method for full field tomographic measurements using a fully non spatially-coherent extended broadband light source and a common path interferometry is described. A layered object's is being tomographed by acquiring multiple images of the object while modulating the spectrum of the extended broadband light source. In order to overcome the non spatially-coherence of the light source, interference fringes are created by amplitude division interferometry at a focal plane of the illuminating optical system and are casted on the measured object. In addition, due to exploiting one of the object's layers as a reference layer for the interference the need for an auxiliary reference beam is avoided and inherent Full Field ;en-face; common path interferometry measurements are obtained. Another advantage is that by using spectrally modulated broadband illumination and obviating the reference beam, the requirement that the object should be used as one of the interferometer arms as in common dual beam interferometry is also avoided. This enables to relay the spectrally modulated light to illuminate the measured object which is just being imaged using a simplified imaging system while modulating the light. However, since there is no reference arm, the tomography of the object is calculated by a complex iterative algorithm where some knowledge on the object's structure is required.

  5. Noninvasive, three-dimensional full-field body sensor for surface deformation monitoring of human body in vivo.

    Science.gov (United States)

    Chen, Zhenning; Shao, Xinxing; He, Xiaoyuan; Wu, Jialin; Xu, Xiangyang; Zhang, Jinlin

    2017-09-01

    Noninvasive, three-dimensional (3-D), full-field surface deformation measurements of the human body are important for biomedical investigations. We proposed a 3-D noninvasive, full-field body sensor based on stereo digital image correlation (stereo-DIC) for surface deformation monitoring of the human body in vivo. First, by applying an improved water-transfer printing (WTP) technique to transfer optimized speckle patterns onto the skin, the body sensor was conveniently and harmlessly fabricated directly onto the human body. Then, stereo-DIC was used to achieve 3-D noncontact and noninvasive surface deformation measurements. The accuracy and efficiency of the proposed body sensor were verified and discussed by considering different complexions. Moreover, the fabrication of speckle patterns on human skin, which has always been considered a challenging problem, was shown to be feasible, effective, and harmless as a result of the improved WTP technique. An application of the proposed stereo-DIC-based body sensor was demonstrated by measuring the pulse wave velocity of human carotid artery. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  6. Full-field displacement and strain measurement of small complex bony structures with digital speckle pattern interferometry and shearography

    Science.gov (United States)

    Soons, Joris; Dirckx, Joris J. J.

    2010-09-01

    We have developed a simple digital speckle pattern interferometry (DSPI) and shearography setup to measure the displacement and the corresponding strains of small complex bony structures. We choose both optical techniques because we want to obtain very small deformations (+/- 20 μm) of small objects (+/- 1cm). Furthermore full field and in situ measurements are preferred. We first use a Michelson DSPI arrangement with phase shifting. In this way we can obtain the out-of-plane displacements precisely. Second, shearography is introduced to measure the derivative of the out-ofplane displacement. In this way some intrinsic disadvantages of DSPI can be overcome. We have developed these setups to measure the out-of-plane deformations of (small) bird beaks when realistic external forces are applied. In this way, we have a full field validation measurement to which we can compare the outcome of realistic finite element models. The aim is to determine whether the shape, and not only the size, of the bird beaks are optimized to deal with the biting forces that a species encounters. This quantitative analysis will help biologists to investigate if beak morphology is adapted to feeding habits. Applying the method to the famous evolution model of the Darwin's finches will provide scientific proof of functional evolution. In this paper we will present both the DSPI and shearography setup, a comparison of the performance of both techniques on a simple deflection of a cantilever beam and the first results obtained on loaded bird beaks.

  7. Defect visualization of aircraft UHF antenna radome using full-field pulse-echo ultrasonic propagation imaging system

    Science.gov (United States)

    Shin, H. J.; Hong, S. C.; Lee, J. R.; Kim, J. H.

    2016-10-01

    Most of aircraft antennas usually have various types of radome made of composite materials for protecting antenna structures. However, these antenna radome structures, which are installed on the outside of airplane, are easy to be damaged by external forces such as drag, foreign object, bird strike and others. In this study, full-field pulse-echo ultrasonic propagation imaging (PE UPI) system is proposed as the non-destructive inspection technique to visualize manufacturing defects in composite antenna radome. Based on the results of the sample case study, it is shown that the ultrasonic wave propagation imaging (UWPI) that is generated by the proposed full-field PE UPI system is able to highlight the intact internal condition of antenna structure and its defect area. Additional damage visualization techniques like ultrasonic energy mapping (UEM), variable time window amplitude map (VTWAM) and also ultrasonic spectral imaging (USI) algorithms are applied to improve the reliability of the damage visualization. It can be concluded that the proposed PE UPI system is an effective non-destructive inspection technique for the composite radome structures.

  8. Noninvasive, three-dimensional full-field body sensor for surface deformation monitoring of human body in vivo

    Science.gov (United States)

    Chen, Zhenning; Shao, Xinxing; He, Xiaoyuan; Wu, Jialin; Xu, Xiangyang; Zhang, Jinlin

    2017-09-01

    Noninvasive, three-dimensional (3-D), full-field surface deformation measurements of the human body are important for biomedical investigations. We proposed a 3-D noninvasive, full-field body sensor based on stereo digital image correlation (stereo-DIC) for surface deformation monitoring of the human body in vivo. First, by applying an improved water-transfer printing (WTP) technique to transfer optimized speckle patterns onto the skin, the body sensor was conveniently and harmlessly fabricated directly onto the human body. Then, stereo-DIC was used to achieve 3-D noncontact and noninvasive surface deformation measurements. The accuracy and efficiency of the proposed body sensor were verified and discussed by considering different complexions. Moreover, the fabrication of speckle patterns on human skin, which has always been considered a challenging problem, was shown to be feasible, effective, and harmless as a result of the improved WTP technique. An application of the proposed stereo-DIC-based body sensor was demonstrated by measuring the pulse wave velocity of human carotid artery.

  9. 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.

  10. Development of a full waveform digital sonic tool and its field application; Full wave onpa kenso sochi no kaihatsu to genchi tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Inazaki, T. [Geological Survey of Japan, Tsukuba (Japan); Kurahashi, T. [Public Works Research Institute, Tsukuba (Japan); Goebuchi, T. [OYO Corp., Tokyo (Japan)

    1997-10-22

    Full waveform digital sonic tool (OYO) has been developed for the purpose of accurately measuring geophysical anomalies in the rockbed containing cracks, and its performance is evaluated by comparing its measurements with those obtained by the conventional sonic logging device (DBM). Modification involves the following. While gain is fixed in the DBM, it is variable in a times10-times200 range in the OYO. Analog transfer:ground surface A/D in the DBM is replaced by digital transfer:intra-probe A/D in the OYO. In the DBM, only a special program running on the MS-DOS can analyze waveform data but, in the OYO, waveforms are recorded in the SEG-Y format enabling the import of the data into generally available waveform processing software. In the OYO, a high-speed communication board is incorporated into the probe, which realizes high-speed communication. There is a very excellent agreement between the two in P-wave velocity distribution as reckoned from the initial run. Regarding the OYO, however, it is pointed out that gain control be performed with the greatest care to prevent waveforms from distortion. 5 figs.

  11. Complete data preparation flow for Massively Parallel E-Beam lithography on 28nm node full-field design

    Science.gov (United States)

    Fay, Aurélien; Browning, Clyde; Brandt, Pieter; Chartoire, Jacky; Bérard-Bergery, Sébastien; Hazart, Jérôme; Chagoya, Alexandre; Postnikov, Sergei; Saib, Mohamed; Lattard, Ludovic; Schavione, Patrick

    2016-03-01

    Massively parallel mask-less electron beam lithography (MP-EBL) offers a large intrinsic flexibility at a low cost of ownership in comparison to conventional optical lithography tools. This attractive direct-write technique needs a dedicated data preparation flow to correct both electronic and resist processes. Moreover, Data Prep has to be completed in a short enough time to preserve the flexibility advantage of MP-EBL. While the MP-EBL tools have currently entered an advanced stage of development, this paper will focus on the data preparation side of the work for specifically the MAPPER Lithography FLX-1200 tool [1]-[4], using the ASELTA Nanographics Inscale software. The complete flow as well as the methodology used to achieve a full-field layout data preparation, within an acceptable cycle time, will be presented. Layout used for Data Prep evaluation was one of a 28 nm technology node Metal1 chip with a field size of 26x33mm2, compatible with typical stepper/scanner field sizes and wafer stepping plans. Proximity Effect Correction (PEC) was applied to the entire field, which was then exported as a single file to MAPPER Lithography's machine format, containing fractured shapes and dose assignments. The Soft Edge beam to beam stitching method was employed in the specific overlap regions defined by the machine format as well. In addition to PEC, verification of the correction was included as part of the overall data preparation cycle time. This verification step was executed on the machine file format to ensure pattern fidelity and accuracy as late in the flow as possible. Verification over the full chip, involving billions of evaluation points, is performed both at nominal conditions and at Process Window corners in order to ensure proper exposure and process latitude. The complete MP-EBL data preparation flow was demonstrated for a 28 nm node Metal1 layout in 37 hours. The final verification step shows that the Edge Placement Error (EPE) is kept below 2.25 nm

  12. Field Testing of a Wet FGD Additive for Enhanced Mercury Control - Task 5 Full-Scale Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Gary Blythe; MariJon Owens

    2007-12-01

    This Topical Report summarizes progress on Cooperative Agreement DE-FC26-04NT42309, 'Field Testing of a Wet FGD Additive'. The objective of the project is to demonstrate the use of two flue gas desulfurization (FGD) additives, Evonik Degussa Corporation's TMT-15 and Nalco Company's Nalco 8034, to prevent the re-emission of elemental mercury (Hg{sup 0}) in flue gas exiting wet FGD systems on coal-fired boilers. Furthermore, the project intends to demonstrate whether the additive can be used to precipitate most of the mercury (Hg) removed in the wet FGD system as a fine salt that can be separated from the FGD liquor and bulk solid byproducts for separate disposal. The project is conducting pilot- and full-scale tests of the additives in wet FGD absorbers. The tests are intended to determine required additive dosages to prevent Hg{sup 0} re-emissions and to separate mercury from the normal FGD byproducts for three coal types: Texas lignite/Powder River Basin (PRB) coal blend, high-sulfur Eastern bituminous coal, and low-sulfur Eastern bituminous coal. The project team consists of URS Group, Inc., EPRI, Luminant Power (was TXU Generation Company LP), Southern Company, IPL (an AES company), Evonik Degussa Corporation and the Nalco Company. Luminant Power has provided the Texas lignite/PRB co-fired test site for pilot FGD tests and cost sharing. Southern Company has provided the low-sulfur Eastern bituminous coal host site for wet scrubbing tests, as well as the pilot- and full-scale jet bubbling reactor (JBR) FGD systems tested. IPL provided the high-sulfur Eastern bituminous coal full-scale FGD test site and cost sharing. Evonik Degussa Corporation is providing the TMT-15 additive, and the Nalco Company is providing the Nalco 8034 additive. Both companies are also supplying technical support to the test program as in-kind cost sharing. The project is being conducted in six tasks. Of the six project tasks, Task 1 involves project planning and Task 6

  13. Full-zone spectral envelope function formalism for the optimization of line and point tunnel field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Verreck, Devin, E-mail: devin.verreck@imec.be; Groeseneken, Guido [imec, Kapeldreef 75, 3001 Leuven (Belgium); Department of Electrical Engineering, KU Leuven, 3001 Leuven (Belgium); Verhulst, Anne S.; Mocuta, Anda; Collaert, Nadine; Thean, Aaron [imec, Kapeldreef 75, 3001 Leuven (Belgium); Van de Put, Maarten; Magnus, Wim [imec, Kapeldreef 75, 3001 Leuven (Belgium); Department of Physics, Universiteit Antwerpen, 2020 Antwerpen (Belgium); Sorée, Bart [imec, Kapeldreef 75, 3001 Leuven (Belgium); Department of Physics, Universiteit Antwerpen, 2020 Antwerpen (Belgium); Department of Electrical Engineering, KU Leuven, 3001 Leuven (Belgium)

    2015-10-07

    Efficient quantum mechanical simulation of tunnel field-effect transistors (TFETs) is indispensable to allow for an optimal configuration identification. We therefore present a full-zone 15-band quantum mechanical solver based on the envelope function formalism and employing a spectral method to reduce computational complexity and handle spurious solutions. We demonstrate the versatility of the solver by simulating a 40 nm wide In{sub 0.53}Ga{sub 0.47}As lineTFET and comparing it to p-n-i-n configurations with various pocket and body thicknesses. We find that the lineTFET performance is not degraded compared to semi-classical simulations. Furthermore, we show that a suitably optimized p-n-i-n TFET can obtain similar performance to the lineTFET.

  14. Three dimensional evaluation of aluminum plates with wall-thinning by full-field pulse-echo laser ultrasound

    Science.gov (United States)

    Hong, Seung-Chan; Abetew, Ayalsew-Dagnew; Lee, Jung-Ryul; Ihn, Jeong-Beom

    2017-12-01

    We propose a full-field pulse-echo laser ultrasonic wave propagation imager (FF-PE-UPI) for the evaluation of structural defects. The FF-PE-UPI consists of a Q-switched laser for the generation of thermoelastic waves, a laser Doppler vibrometer (LDV) for sensing, and a two-axis translation stage for raster scanning of the combined generation and sensing laser beams. A-scan, B-scan, and C-scan data representations are used for the evaluation of structural defects. Three specimens were tested: a 4-mm aluminum plate with an area of 50% thickness reduction, a 6-mm aluminum plate with an area of 25% thickness reduction, and an 8-mm aluminum plate with engraved letters. The damages on the tested specimens were successfully visualized.

  15. High-dynamic-range microscope imaging based on exposure bracketing in full-field optical coherence tomography.

    Science.gov (United States)

    Leong-Hoi, Audrey; Montgomery, Paul C; Serio, Bruno; Twardowski, Patrice; Uhring, Wilfried

    2016-04-01

    By applying the proposed high-dynamic-range (HDR) technique based on exposure bracketing, we demonstrate a meaningful reduction in the spatial noise in image frames acquired with a CCD camera so as to improve the fringe contrast in full-field optical coherence tomography (FF-OCT). This new signal processing method thus allows improved probing within transparent or semitransparent samples. The proposed method is demonstrated on 3 μm thick transparent polymer films of Mylar, which, due to their transparency, produce low contrast fringe patterns in white-light interference microscopy. High-resolution tomographic analysis is performed using the technique. After performing appropriate signal processing, resulting XZ sections are observed. Submicrometer-sized defects can be lost in the noise that is present in the CCD images. With the proposed method, we show that by increasing the signal-to-noise ratio of the images, submicrometer-sized defect structures can thus be detected.

  16. Feasibility of full-field optical coherence microscopy in ultra-structural imaging of human colon tissues

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Eun Seo [Chosun University, Gwangju (Korea, Republic of); Choi, Woo June; Ryu, Seon Young; Lee, Byeong Ha [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Lee, Jae Hyuk; Bom, Hee Seung; Lee, Byeong Il [Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2010-06-15

    We demonstrated the imaging feasibility of full-field optical coherence microscopy (FF-OCM) in pathological diagnosis of human colon tissues. FF-OCM images with high transverse resolution were obtained at different depths of the samples without any dye staining or physical slicing, and detailed microstructures of human colon tissues were visualized. Morphological differences in normal tissues, cancer tissues, and tissues under transition were observed and matched with results seen in conventional optical microscope images. The optical biopsy based on FF-OCM could overcome the limitations on the number of physical cuttings of tissues and could perform high-throughput mass diagnosis of diseased tissues. The proved utility of FF-OCM as a comprehensive and efficient imaging modality of human tissues showed it to be a good alternative to conventional biopsy.

  17. Feasibility of full-field optical coherence microscopy in ultra-structural imaging of human colon tissues

    International Nuclear Information System (INIS)

    Choi, Eun Seo; Choi, Woo June; Ryu, Seon Young; Lee, Byeong Ha; Lee, Jae Hyuk; Bom, Hee Seung; Lee, Byeong Il

    2010-01-01

    We demonstrated the imaging feasibility of full-field optical coherence microscopy (FF-OCM) in pathological diagnosis of human colon tissues. FF-OCM images with high transverse resolution were obtained at different depths of the samples without any dye staining or physical slicing, and detailed microstructures of human colon tissues were visualized. Morphological differences in normal tissues, cancer tissues, and tissues under transition were observed and matched with results seen in conventional optical microscope images. The optical biopsy based on FF-OCM could overcome the limitations on the number of physical cuttings of tissues and could perform high-throughput mass diagnosis of diseased tissues. The proved utility of FF-OCM as a comprehensive and efficient imaging modality of human tissues showed it to be a good alternative to conventional biopsy.

  18. Defect Localization Capabilities of a Global Detection Scheme: Spatial Pattern Recognition Using Full-field Vibration Test Data in Plates

    Science.gov (United States)

    Saleeb, A. F.; Prabhu, M.; Arnold, S. M. (Technical Monitor)

    2002-01-01

    Recently, a conceptually simple approach, based on the notion of defect energy in material space has been developed and extensively studied (from the theoretical and computational standpoints). The present study focuses on its evaluation from the viewpoint of damage localization capabilities in case of two-dimensional plates; i.e., spatial pattern recognition on surfaces. To this end, two different experimental modal test results are utilized; i.e., (1) conventional modal testing using (white noise) excitation and accelerometer-type sensors and (2) pattern recognition using Electronic speckle pattern interferometry (ESPI), a full field method capable of analyzing the mechanical vibration of complex structures. Unlike the conventional modal testing technique (using contacting accelerometers), these emerging ESPI technologies operate in a non-contacting mode, can be used even under hazardous conditions with minimal or no presence of noise and can simultaneously provide measurements for both translations and rotations. Results obtained have clearly demonstrated the robustness and versatility of the global NDE scheme developed. The vectorial character of the indices used, which enabled the extraction of distinct patterns for localizing damages proved very useful. In the context of the targeted pattern recognition paradigm, two algorithms were developed for the interrogation of test measurements; i.e., intensity contour maps for the damaged index, and the associated defect energy vector field plots.

  19. Qualitative and quantitative assessment of cartilage degeneration using full-field optical coherence tomography ex vivo.

    Science.gov (United States)

    Pailhé, R; Mounier, A; Boisson, B; Rouchy, R C; Voros, S; Chipon, E; Boudry, I; Medici, M; Hughes, C; Moreau-Gaudry, A

    2018-02-01

    The purpose of this study was to investigate the ability of full-field optical coherence tomography (FFOCT) to qualitatively and quantitatively evaluate cartilage degeneration using the qualitative evaluation of histology sections as the reference. Thirty-three human knee cartilage samples of variable degeneration were included in the study. A closely matching histology and FFOCT image was acquired for each sample. The cartilage degeneration was qualitatively evaluated by assigning a grade to each histology and FFOCT image. The relevance of the performed grading was assessed by calculating the intra- and inter-observer reproducibility and calculating the concordance between the histology and FFOCT grades. A near-automatic algorithm was developed to quantitatively characterize the cartilage surface in each image. The correlation between the quantitative results and the reference qualitative histology was calculated. An almost perfect agreement was achieved for both the intra- and inter-reproducibility of the histology and FFOCT qualitative grading (κ ≥ 0.91). A high and statistically significant level of agreement was measured between the histology and FFOCT grades (W = 0.95, P quantitative results and the reference qualitative histology grades (ρ ≥ 0.75, P qualitative and quantitative assessment of human cartilage as the reference gold standard - histology. This study constitutes the first promising results towards developing a new diagnostic tool in the field of osteoarthritis. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  20. 3D palmprint and hand imaging system based on full-field composite color sinusoidal fringe projection technique.

    Science.gov (United States)

    Zhang, Zonghua; Huang, Shujun; Xu, Yongjia; Chen, Chao; Zhao, Yan; Gao, Nan; Xiao, Yanjun

    2013-09-01

    Palmprint and hand shape, as two kinds of important biometric characteristics, have been widely studied and applied to human identity recognition. The existing research is based mainly on 2D images, which lose the third-dimensional information. The biological features extracted from 2D images are distorted by pressure and rolling, so the subsequent feature matching and recognition are inaccurate. This paper presents a method to acquire accurate 3D shapes of palmprint and hand by projecting full-field composite color sinusoidal fringe patterns and the corresponding color texture information. A 3D imaging system is designed to capture and process the full-field composite color fringe patterns on hand surface. Composite color fringe patterns having the optimum three fringe numbers are generated by software and projected onto the surface of human hand by a digital light processing projector. From another viewpoint, a color CCD camera captures the deformed fringe patterns and saves them for postprocessing. After compensating for the cross talk and chromatic aberration between color channels, three fringe patterns are extracted from three color channels of a captured composite color image. Wrapped phase information can be calculated from the sinusoidal fringe patterns with high precision. At the same time, the absolute phase of each pixel is determined by the optimum three-fringe selection method. After building up the relationship between absolute phase map and 3D shape data, the 3D palmprint and hand are obtained. Color texture information can be directly captured or demodulated from the captured composite fringe pattern images. Experimental results show that the proposed method and system can yield accurate 3D shape and color texture information of the palmprint and hand shape.

  1. Computer-aided detection of masses in full-field digital mammography using screen-film mammograms for training

    International Nuclear Information System (INIS)

    Kallenberg, Michiel; Karssemeijer, Nico

    2008-01-01

    It would be of great value when available databases of screen-film mammography (SFM) images can be used to train full-field digital mammography (FFDM) computer-aided detection (CAD) systems, as compilation of new databases is costly. In this paper, we investigate this possibility. Firstly, we develop a method that converts an FFDM image into an SFM-like representation. In this conversion method, we establish a relation between exposure and optical density by simulation of an automatic exposure control unit. Secondly, we investigate the effects of using the SFM images as training samples compared to training with FFDM images. Our FFDM database consisted of 266 cases, of which 102 were biopsy-proven malignant masses and 164 normals. The images were acquired with systems of two different manufacturers. We found that, when we trained our FFDM CAD system with a small number of images, training with FFDM images, using a five-fold crossvalidation procedure, outperformed training with SFM images. However, when the full SFM database, consisting of 348 abnormal cases (including 204 priors) and 810 normal cases, was used for training, SFM training outperformed FFDMA training. These results show that an existing CAD system for detection of masses in SFM can be used for FFDM images without retraining.

  2. Peak-locking error reduction by birefringent optical diffusers

    Science.gov (United States)

    Kislaya, Ankur; Sciacchitano, Andrea

    2018-02-01

    The use of optical diffusers for the reduction of peak-locking errors in particle image velocimetry is investigated. The working principle of the optical diffusers is based on the concept of birefringence, where the incoming rays are subject to different deflections depending on the light direction and polarization. The performances of the diffusers are assessed via wind tunnel measurements in uniform flow and wall-bounded turbulence. Comparison with best-practice image defocusing is also conducted. It is found that the optical diffusers yield an increase of the particle image diameter up to 10 µm in the sensor plane. Comparison with reference measurements showed a reduction of both random and systematic errors by a factor of 3, even at low imaging signal-to-noise ratio.

  3. 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.

  4. Directional eye fixation sensor using birefringence-based foveal detection

    Science.gov (United States)

    Gramatikov, Boris I.; Zalloum, Othman H. Y.; Wu, Yi Kai; Hunter, David G.; Guyton, David L.

    2007-04-01

    We recently developed and reported an eye fixation monitor that detects the fovea by its radial orientation of birefringent nerve fibers. The instrument used a four-quadrant photodetector and a normalized difference function to check for a best match between the detector quadrants and the arms of the bow-tie pattern of polarization states surrounding the fovea. This function had a maximum during central fixation but could not tell where the subject was looking relative to the center. We propose a linear transformation to obtain horizontal and vertical eye position coordinates from the four photodetector signals, followed by correction based on a priori calibration information. The method was verified on both a computer model and on human eyes. The major advantage of this new eye-tracking method is that it uses true information coming from the fovea, rather than reflections from other structures, to identify the direction of foveal gaze.

  5. Two-dimensional electronic spectroscopy with birefringent wedges

    Science.gov (United States)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio

    2014-12-01

    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.

  6. Full Field Deformation Measurements in Tensile Kolsky Bar Experiments: Studies and Detailed Analysis of the Early Time History

    Science.gov (United States)

    Sutton, M. A.; Gilat, A.; Seidt, J.; Rajan, S.; Kidane, A.

    2018-01-01

    The very early stages of high rate tensile loading are important when attempting to characterize the response of materials during the transient loading time. To improve understanding of the conditions imposed on the specimen during the transient stage, a series of high rate loading experiments are performed using a Kolsky tensile bar system. Specimen forces and velocities during the high rate loading experiment are obtained by performing a thorough method of characteristics analysis of the system employed in the experiments. The in-situ full-field specimen displacements, velocities and accelerations during the loading process are quantified using modern ultra-high-speed imaging systems to provide detailed measurements of specimen response, with emphasis on the earliest stages of loading. Detailed analysis of the image-based measurements confirms that conditions are nominally consistent with those necessary for use of the one-dimensional wave equation within the relatively thin, dog-bone shaped tensile specimen. Specifically, measurements and use of the one-dimensional wave equation show clearly that the specimen has low inertial stresses in comparison to the applied transmitted force. Though the accelerations of the specimen continue for up to 50 μs, measurements show that the specimen is essentially in force equilibrium beginning a few microseconds after initial loading. These local measurements contrast with predictions based on comparison of the wave-based incident force measurements, which suggest that equilibrium occurs much later, on the order of 40-50 μs .

  7. Comparing search patterns in digital breast tomosynthesis and full-field digital mammography: an eye tracking study.

    Science.gov (United States)

    Aizenman, Avi; Drew, Trafton; Ehinger, Krista A; Georgian-Smith, Dianne; Wolfe, Jeremy M

    2017-10-01

    As a promising imaging modality, digital breast tomosynthesis (DBT) leads to better diagnostic performance than traditional full-field digital mammograms (FFDM) alone. DBT allows different planes of the breast to be visualized, reducing occlusion from overlapping tissue. Although DBT is gaining popularity, best practices for search strategies in this medium are unclear. Eye tracking allowed us to describe search patterns adopted by radiologists searching DBT and FFDM images. Eleven radiologists examined eight DBT and FFDM cases. Observers marked suspicious masses with mouse clicks. Eye position was recorded at 1000 Hz and was coregistered with slice/depth plane as the radiologist scrolled through the DBT images, allowing a 3-D representation of eye position. Hit rate for masses was higher for tomography cases than 2-D cases and DBT led to lower false positive rates. However, search duration was much longer for DBT cases than FFDM. DBT was associated with longer fixations but similar saccadic amplitude compared with FFDM. When comparing radiologists' eye movements to a previous study, which tracked eye movements as radiologists read chest CT, we found DBT viewers did not align with previously identified "driller" or "scanner" strategies, although their search strategy most closely aligns with a type of vigorous drilling strategy.

  8. 50-nm-resolution full-field X-ray microscope without chromatic aberration using total-reflection imaging mirrors.

    Science.gov (United States)

    Matsuyama, Satoshi; Yasuda, Shuhei; Yamada, Jumpei; Okada, Hiromi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2017-04-13

    X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick-Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10 keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20 h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles.

  9. Studies Comparing Screen-Film Mammography and Full-Field Digital Mammography in Breast Cancer Screening: Updated Review

    International Nuclear Information System (INIS)

    Skaane, P.

    2009-01-01

    Full-field digital mammography (FFDM) has several potential benefits as compared with screen-film mammography (SFM) in mammography screening. Digital technology also opens for implementation of advanced applications, including computer-aided detection (CAD) and tomosynthesis. Phantom studies and experimental clinical studies have shown that FFDM is equal or slightly superior to SFM for detection and characterization of mammographic abnormalities. Despite obvious advantages, the conversion to digital mammography has been slower than anticipated, and not only due to higher costs. Until very recently, some countries did not even permit the use of digital mammography in breast cancer screening. The reason for this reluctant attitude was concern about lower spatial resolution and about using soft-copy reading. Furthermore, there was a lack of data supporting improved diagnostic accuracy using FFDM in a screening setting, since two pioneer trials both showed nonsignificantly lower cancer detection rate at FFDM. The 10 studies comparing FFDM and SFM in mammography screening published so far have shown divergent and rather conflicting results. Nevertheless, there is a rapid conversion to digital mammography in breast cancer screening in many western countries. The aim of this article is to give an updated review of these studies, discuss the conflicting findings, and draw some conclusions from the results

  10. Compartmentalization of the Coso East Flank geothermal field imaged by 3-D full-tensor MT inversion

    Science.gov (United States)

    Lindsey, Nathaniel J.; Kaven, Joern; Davatzes, Nicholas C.; Newman, Gregory A.

    2017-01-01

    Previous magnetotelluric (MT) studies of the high-temperature Coso geothermal system in California identified a subvertical feature of low resistivity (2–5 Ohm m) and appreciable lateral extent (>1 km) in the producing zone of the East Flank field. However, these models could not reproduce gross 3-D effects in the recorded data. We perform 3-D full-tensor inversion and retrieve a resistivity model that out-performs previous 2-D and 3-D off-diagonal models in terms of its fit to the complete 3-D MT data set as well as the degree of modelling bias. Inclusion of secondary Zxx and Zyy data components leads to a robust east-dip (60†) to the previously identified conductive East Flank reservoir feature, which correlates strongly with recently mapped surface faults, downhole well temperatures, 3-D seismic reflection data, and local microseismicity. We perform synthetic forward modelling to test the best-fit dip of this conductor using the response at a nearby MT station. We interpret the dipping conductor as a fractured and fluidized compartment, which is structurally controlled by an unmapped blind East Flank fault zone.

  11. Performance of computer-aided detection applied to full-field digital mammography in detection of breast cancers

    International Nuclear Information System (INIS)

    Sadaf, Arifa; Crystal, Pavel; Scaranelo, Anabel; Helbich, Thomas

    2011-01-01

    Objective: The aim of this retrospective study was to evaluate performance of computer-aided detection (CAD) with full-field digital mammography (FFDM) in detection of breast cancers. Materials and Methods: CAD was retrospectively applied to standard mammographic views of 127 cases with biopsy proven breast cancers detected with FFDM (Senographe 2000, GE Medical Systems). CAD sensitivity was assessed in total group of 127 cases and for subgroups based on breast density, mammographic lesion type, mammographic lesion size, histopathology and mode of presentation. Results: Overall CAD sensitivity was 91% (115 of 127 cases). There were no statistical differences (p > 0.1) in CAD detection of cancers in dense breasts 90% (53/59) versus non-dense breasts 91% (62/68). There was statistical difference (p 20 mm 97% (22/23). Conclusion: CAD applied to FFDM showed 100% sensitivity in identifying cancers manifesting as microcalcifications only and high sensitivity 86% (71/83) for other mammographic appearances of cancer. Sensitivity is influenced by lesion size. CAD in FFDM is an adjunct helping radiologist in early detection of breast cancers.

  12. Observer variability in screen-film mammography versus full-field digital mammography with soft-copy reading

    Energy Technology Data Exchange (ETDEWEB)

    Skaane, Per; Young, Kari [Ullevaal University Hospital, Department of Radiology, Breast Imaging Center, Oslo (Norway); Diekmann, Felix; Diekmann, Susanne [University Charite, Department of Diagnostic Radiology, Berlin (Germany); Balleyguier, Corinne [Institut Gustave Roussy, Villejuif (France); Piguet, Jean-Charles [Institut Imagerive, Geneva (Switzerland); Abdelnoor, Michael [Ullevaal University Hospital, Center for Clinical Research, Section of Epidemiology and Biostatistics, Oslo (Norway); Niklason, Loren [Hologic Inc., Hillsborough, NC (United States)

    2008-06-15

    Full-field digital mammography (FFDM) with soft-copy reading is more complex than screen-film mammography (SFM) with hard-copy reading. The aim of this study was to compare inter- and intraobserver variability in SFM versus FFDM of paired mammograms from a breast cancer screening program. Six radiologists interpreted mammograms of 232 cases obtained with both techniques, including 46 cancers, 88 benign lesions, and 98 normals. Image interpretation included BI-RADS categories. A case consisted of standard two-view mammograms of one breast. Images were scored in two sessions separated by 5 weeks. Observer variability was substantial for SFM as well as for FFDM, but overall there was no significant difference between the observer variability at SFM and FFDM. Mean kappa values were lower, indicating less agreement, for microcalcifications compared with masses. The lower observer agreement for microcalcifications, and especially the low intraobserver concordance between the two imaging techniques for three readers, was noticeable. The level of observer agreement might be an indicator of radiologist performance and could confound studies designed to separate diagnostic differences between the two imaging techniques. The results of our study confirm the need for proper training for radiologists starting FFDM with soft-copy reading in breast cancer screening. (orig.)

  13. Compartmentalization of the Coso East Flank geothermal field imaged by 3-D full-tensor MT inversion

    Science.gov (United States)

    Lindsey, Nathaniel J.; Kaven, Joern Ole; Davatzes, Nicholas; Newman, Gregory A.

    2017-02-01

    Previous magnetotelluric (MT) studies of the high-temperature Coso geothermal system in California identified a subvertical feature of low resistivity (2-5 Ohm m) and appreciable lateral extent (>1 km) in the producing zone of the East Flank field. However, these models could not reproduce gross 3-D effects in the recorded data. We perform 3-D full-tensor inversion and retrieve a resistivity model that out-performs previous 2-D and 3-D off-diagonal models in terms of its fit to the complete 3-D MT data set as well as the degree of modelling bias. Inclusion of secondary Zxx and Zyy data components leads to a robust east-dip (60†) to the previously identified conductive East Flank reservoir feature, which correlates strongly with recently mapped surface faults, downhole well temperatures, 3-D seismic reflection data, and local microseismicity. We perform synthetic forward modelling to test the best-fit dip of this conductor using the response at a nearby MT station. We interpret the dipping conductor as a fractured and fluidized compartment, which is structurally controlled by an unmapped blind East Flank fault zone.

  14. Fast subsurface fingerprint imaging with full-field optical coherence tomography system equipped with a silicon camera.

    Science.gov (United States)

    Auksorius, Egidijus; Boccara, A Claude

    2017-09-01

    Images recorded below the surface of a finger can have more details and be of higher quality than the conventional surface fingerprint images. This is particularly true when the quality of the surface fingerprints is compromised by, for example, moisture or surface damage. However, there is an unmet need for an inexpensive fingerprint sensor that is able to acquire high-quality images deep below the surface in short time. To this end, we report on a cost-effective full-field optical coherent tomography system comprised of a silicon camera and a powerful near-infrared LED light source. The system, for example, is able to record 1.7  cm×1.7  cmen face images in 0.12 s with the spatial sampling rate of 2116 dots per inch and the sensitivity of 93 dB. We show that the system can be used to image internal fingerprints and sweat ducts with good contrast. Finally, to demonstrate its biometric performance, we acquired subsurface fingerprint images from 240 individual fingers and estimated the equal-error-rate to be ∼0.8%. The developed instrument could also be used in other en face deep-tissue imaging applications because of its high sensitivity, such as in vivo skin imaging. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  15. Impact of full-field digital mammography on pre-operative diagnosis and surgical treatment of mammographic microcalcification.

    Science.gov (United States)

    Bundred, S M; Zhou, J; Whiteside, S; Morris, J; Wilson, M; Hurley, E; Bundred, N

    2014-01-01

    Accurate pre-operative diagnosis of impalpable breast lesions correlates closely with the number of surgical procedures required for treatment. Correct diagnosis of mammographic microcalcification (MM) as ductal carcinoma in situ (DCIS) or invasive breast cancer is important because lesions upgraded to malignant diagnosis at surgery require repeat surgical procedures in 44 % of cases. Despite correct pre-operative diagnosis of MM, 26 % require second therapeutic operations to achieve surgical clearance. Theoretically, improved conspicuity of malignant MM using digital mammography could improve diagnostic work-up and improve surgical outcomes for MM. To determine the impact of full-field digital mammography (FFDM) on the diagnostic accuracy and positive predictive value (PPV) of biopsy of MM and surgical management of MM, screening and symptomatic cases with MM (n = 1,479) were reviewed for women imaged between August 2007 and March 2010 using screen-film mammography (SFM) (n = 711), and using FFDM, imaged between April 2010 to March 2012 (n = 768). Demographic information including pre and postoperative diagnosis, and number and types of surgical procedures were recorded. Overall, 302 (128 invasive) and 251 (110 invasive) malignant lesions were diagnosed using SFM and FFDM, respectively. Reduction in PPV of biopsy was observed (SFM 42.5 %; FFDM 32.7 %, p cancers over two centimetres. This will increase concerns about treatment of lesions detected in the screening programme with widespread use of digital mammography.

  16. Effect of Pupil Size on Flicker ERGs Recorded With RETeval System: New Mydriasis-Free Full-Field ERG System.

    Science.gov (United States)

    Kato, Kumiko; Kondo, Mineo; Sugimoto, Masahiko; Ikesugi, Kengo; Matsubara, Hisashi

    2015-06-01

    We studied whether pupil size affects the flicker electroretinograms (ERGs) recorded by RETeval, a new mydriasis-free full-field flicker ERG system. We studied 10 healthy subjects. The RETeval manufacturer claims that the system delivers a constant flash retinal illuminance by adjusting the flash luminance to compensate for changes in the pupil size. Two experiments were performed. First, the flicker ERG was recorded every 3 minutes after the instillation of mydriatics. Second, the flicker ERG was recorded while the subjects wore soft contact lenses with two different artificial pupil sizes. The first experiment showed that as pupil size increased, the amplitudes of the fundamental component of the flicker ERG did not change significantly, but the implicit times of the fundamental component were significantly prolonged for larger pupil sizes. There was a significant positive correlation between the pupillary area and implicit time of the fundamental component (r = 0.93, P flicker ERG were significantly longer with larger artificial pupil. The results suggest that the effective retinal illuminance of the stimulus delivered by the RETeval system decreases for large pupil sizes. However, in most clinical testing situations, patients' undilated pupils will likely be sufficiently small to fall within the range for which the system delivers a stimulus of constant retinal illuminance.

  17. Applying neutron transmission physics and 3D statistical full-field model to understand 2D Bragg-edge imaging

    Science.gov (United States)

    Xie, Q.; Song, G.; Gorti, S.; Stoica, A. D.; Radhakrishnan, B.; Bilheux, J. C.; Kirka, M.; Dehoff, R.; Bilheux, H. Z.; An, K.

    2018-02-01

    Bragg-edge imaging, which is also known as neutron radiography, has recently emerged as a novel crystalline characterization technique. Modelling of this novel technique by incorporating various features of the underlying microstructure (including the crystallographic texture, the morphological texture, and the grain size) of the material remains a subject of considerable research and development. In this paper, Inconel 718 samples made by additive manufacturing were investigated by neutron diffraction and neutron radiography techniques. The specimen features strong morphological and crystallographic textures and a highly heterogeneous microstructure. A 3D statistical full-field model is introduced by taking details of the microstructure into account to understand the experimental neutron radiography results. The Bragg-edge imaging and the total cross section were calculated based on the neutron transmission physics. A good match was obtained between the model predictions and experimental results at different incident beam angles with respect to the sample build direction. The current theoretical approach has the ability to incorporate 3D spatially resolved microstructural heterogeneity information and shows promise in understanding the 2D neutron radiography of bulk samples. With further development to incorporate the heterogeneity in lattice strain in the model, it can be used as a powerful tool in the future to better understand the neutron radiography data.

  18. 50-nm-resolution full-field X-ray microscope without chromatic aberration using total-reflection imaging mirrors

    Science.gov (United States)

    Matsuyama, Satoshi; Yasuda, Shuhei; Yamada, Jumpei; Okada, Hiromi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2017-04-01

    X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick-Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10 keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20 h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles.

  19. Optical low-cost and portable arrangement for full field 3D displacement measurement using a single camera

    Science.gov (United States)

    López-Alba, E.; Felipe-Sesé, L.; Schmeer, S.; Díaz, F. A.

    2016-11-01

    In the current paper, an optical low-cost system for 3D displacement measurement based on a single camera and 3D digital image correlation is presented. The conventional 3D-DIC set-up based on a two-synchronized-cameras system is compared with a proposed pseudo-stereo portable system that employs a mirror system integrated in a device for a straightforward application achieving a novel handle and flexible device for its use in many scenarios. The proposed optical system splits the image by the camera into two stereo images of the object. In order to validate this new approach and quantify its uncertainty compared to traditional 3D-DIC systems, solid rigid in and out-of-plane displacements experiments have been performed and analyzed. The differences between both systems have been studied employing an image decomposition technique which performs a full image comparison. Therefore, results of all field of view are compared with those using a stereoscopy system and 3D-DIC, discussing the accurate results obtained with the proposed device not having influence any distortion or aberration produced by the mirrors. Finally, the adaptability of the proposed system and its accuracy has been tested performing quasi-static and dynamic experiments using a silicon specimen under high deformation. Results have been compared and validated with those obtained from a conventional stereoscopy system showing an excellent level of agreement.

  20. Three-dimensional seismic full waveform inversion of ocean bottom cable data from the Valhall oil field

    Science.gov (United States)

    Etienne, V.; Hu, G.; Operto, S.; Virieux, J.

    2012-04-01

    In the past few years, the ability to reconstruct accurate 3D velocity models by full waveform inversion (FWI) has been shown by the academic research and the oil industry. In this study, we present a massively parallel algorithm for 3D seismic FWI together with an application to the ocean bottom cable (OBC) data from the Valhall oil field (North Sea). To achieve a computational efficiency and a flexible algorithm, we design a process, which can combine various forward modelling engines (such as finite-difference or finite-element methods) in time or frequency domains and an inversion core formulated in the frequency domain. Our algorithm relies on two key features: (1) the parametrizations of the subsurface for the seismic modeling and the inversion are uncoupled, that allows to interface different modeling engines with the inversion, and to consider target-oriented imaging. (2) Two nested levels of parallelism, by source distribution and domain decomposition, are implemented for the optimization of the performances of the scheme with respect to the computational platform, the dimensions of the model and the acquisition geometry. We present an application of our algorithm to OBC data recorded in the Valhall oil field. A total of 49 954 air-gun sources and 2 302 receivers located at the sea-floor (70 m depth) are used in this seismic experiment. The dimensions of the inverted target are 9.6 x 16.6 x 4.8 km. For the forward modelling, we adopt a finite-difference method in time to solve the acoustic wave equation, and monochromatic solutions are extracted from time signals. For the inversion, three overlapping groups of frequencies, [3.5 - 4], [4 - 5] and [5 - 7] Hz, respectively, are inverted successively to build a P-wave velocity model from the hydrophone component. The algorithm is performed on a IBM Blue Gene computer, by combining source distribution and domain decomposition over several hundreds of processors. The final FWI model exhibits remarkable

  1. Assessing tumor extent on contrast-enhanced spectral mammography versus full-field digital mammography and ultrasound.

    Science.gov (United States)

    Patel, Bhavika K; Garza, Sandra Alheli; Eversman, Sarah; Lopez-Alvarez, Yania; Kosiorek, Heidi; Pockaj, Barbara A

    To compare breast cancer size measurements on full-field digital mammography (FFDM), contrast-enhanced spectral mammography (CEDM), and ultrasound (US), with histologic tumor size used as the reference standard. Material and methods The HIPAA complaint, IRB approved study comprised 88 women with newly diagnosed breast cancer who underwent FFDM and CEDM;74 also had US. Breast density, histologic subtype, and maximum tumor measurements were recorded. Pearson correlation coefficients for FFDM, US, and CEDM vs histopathology were 0.598, 0.639, and 0.859, respectively (P<0.001). The following correlation coefficients were calculated for dense breasts (n=48): histopathology vs FFDM (0.555), US (0.633), and CEDM (0.843) (P<0.001); for nondense breasts (n=40), they were FFDM (0.618), US (0.512), and CEDM (0.885) (P<0.001). For size difference, the mean (SD) for histopathology vs FFDM, US, and CEDM was -1.3 (11.9) mm, -2.8 (11.1) mm, and 2.9 (9.5) mm, respectively. Limits of agreement were -24.8 to 22.0mm, -24.5 to 18.8mm, and -15.6 to 21.4mm, respectively. In patients with biopsy-proven malignancy, size measurements correlated well with histopathologic size, and were higher on CEDM than those for FFDM and US in patients with dense or nondense breasts. The added value of CEDM as a supplement to FFDM in determining tumor size, however, was greater in patients with dense breasts. CEDM may be a promising alternative preoperative measurement tool for breast cancer patients with dense breasts and/or limited access or contraindications to MRI. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Interior tomography in microscopic CT with image reconstruction constrained by full field of view scan at low spatial resolution

    Science.gov (United States)

    Luo, Shouhua; Shen, Tao; Sun, Yi; Li, Jing; Li, Guang; Tang, Xiangyang

    2018-04-01

    In high resolution (microscopic) CT applications, the scan field of view should cover the entire specimen or sample to allow complete data acquisition and image reconstruction. However, truncation may occur in projection data and results in artifacts in reconstructed images. In this study, we propose a low resolution image constrained reconstruction algorithm (LRICR) for interior tomography in microscopic CT at high resolution. In general, the multi-resolution acquisition based methods can be employed to solve the data truncation problem if the project data acquired at low resolution are utilized to fill up the truncated projection data acquired at high resolution. However, most existing methods place quite strict restrictions on the data acquisition geometry, which greatly limits their utility in practice. In the proposed LRICR algorithm, full and partial data acquisition (scan) at low and high resolutions, respectively, are carried out. Using the image reconstructed from sparse projection data acquired at low resolution as the prior, a microscopic image at high resolution is reconstructed from the truncated projection data acquired at high resolution. Two synthesized digital phantoms, a raw bamboo culm and a specimen of mouse femur, were utilized to evaluate and verify performance of the proposed LRICR algorithm. Compared with the conventional TV minimization based algorithm and the multi-resolution scout-reconstruction algorithm, the proposed LRICR algorithm shows significant improvement in reduction of the artifacts caused by data truncation, providing a practical solution for high quality and reliable interior tomography in microscopic CT applications. The proposed LRICR algorithm outperforms the multi-resolution scout-reconstruction method and the TV minimization based reconstruction for interior tomography in microscopic CT.

  3. Validation of image quality in full-field digital mammography: is the replacement of wet by dry laser printers justified?

    Science.gov (United States)

    Schueller, Gerd; Kaindl, Elisabeth; Langenberger, Herbert; Stadler, Alfred; Schueller-Weidekamm, Claudia; Semturs, Friedrich; Helbich, Thomas H

    2007-05-01

    Dry laser printers have replaced wet laser printers to produce hard copies of high-resolution digital images, primarily because of environmental concerns. However, no scientific research data have been published that compare the image quality of dry and wet laser printers in full-field digital mammography (FFDM). This study questions the image quality of these printers. Objective image quality parameters of both printers were evaluated using a standardized printer test image, i.e., optical density and detectability of specific image elements (lines, curves, and shapes). Furthermore, mammograms of 129 patients with different breast tissue composition patterns were imaged with both printers. A total of 1806 subjective image quality parameters (brightness, contrast, and detail detection of anatomic structures), the detectability of breast lesions, as well as diagnostic performance according to the BI-RADS classification were evaluated. In addition, the presence of film artifacts was investigated. Optical density values were equal for the dry and the wet laser printer. Detection of specific image elements on the printer test image was not different. Ratings of subjective image quality parameters were equal, as were the detectability of breast lesions and the diagnostic performance. Dry laser printer images showed more artifacts (164 versus 27). However, these artifacts did not influence image quality. Based on the evidence of objective and subjective parameters, a dry laser printer equals the image quality of a wet laser printer in FFDM. Therefore, not only for reasons of environmental preference, the replacement of wet laser printers by dry laser printers in FFDM is justified.

  4. Validation of image quality in full-field digital mammography: Is the replacement of wet by dry laser printers justified?

    International Nuclear Information System (INIS)

    Schueller, Gerd; Kaindl, Elisabeth; Langenberger, Herbert; Stadler, Alfred; Schueller-Weidekamm, Claudia; Semturs, Friedrich; Helbich, Thomas H.

    2007-01-01

    Objective: Dry laser printers have replaced wet laser printers to produce hard copies of high-resolution digital images, primarily because of environmental concerns. However, no scientific research data have been published that compare the image quality of dry and wet laser printers in full-field digital mammography (FFDM). This study questions the image quality of these printers. Materials and methods: Objective image quality parameters of both printers were evaluated using a standardized printer test image, i.e., optical density and detectability of specific image elements (lines, curves, and shapes). Furthermore, mammograms of 129 patients with different breast tissue composition patterns were imaged with both printers. A total of 1806 subjective image quality parameters (brightness, contrast, and detail detection of anatomic structures), the detectability of breast lesions, as well as diagnostic performance according to the BI-RADS classification were evaluated. In addition, the presence of film artifacts was investigated. Results: Optical density values were equal for the dry and the wet laser printer. Detection of specific image elements on the printer test image was not different. Ratings of subjective image quality parameters were equal, as were the detectability of breast lesions and the diagnostic performance. Dry laser printer images showed more artifacts (164 versus 27). However, these artifacts did not influence image quality. Conclusion: Based on the evidence of objective and subjective parameters, a dry laser printer equals the image quality of a wet laser printer in FFDM. Therefore, not only for reasons of environmental preference, the replacement of wet laser printers by dry laser printers in FFDM is justified

  5. Microcalcification detection in full-field digital mammograms with PFCM clustering and weighted SVM-based method

    Science.gov (United States)

    Liu, Xiaoming; Mei, Ming; Liu, Jun; Hu, Wei

    2015-12-01

    Clustered microcalcifications (MCs) in mammograms are an important early sign of breast cancer in women. Their accurate detection is important in computer-aided detection (CADe). In this paper, we integrated the possibilistic fuzzy c-means (PFCM) clustering algorithm and weighted support vector machine (WSVM) for the detection of MC clusters in full-field digital mammograms (FFDM). For each image, suspicious MC regions are extracted with region growing and active contour segmentation. Then geometry and texture features are extracted for each suspicious MC, a mutual information-based supervised criterion is used to select important features, and PFCM is applied to cluster the samples into two clusters. Weights of the samples are calculated based on possibilities and typicality values from the PFCM, and the ground truth labels. A weighted nonlinear SVM is trained. During the test process, when an unknown image is presented, suspicious regions are located with the segmentation step, selected features are extracted, and the suspicious MC regions are classified as containing MC or not by the trained weighted nonlinear SVM. Finally, the MC regions are analyzed with spatial information to locate MC clusters. The proposed method is evaluated using a database of 410 clinical mammograms and compared with a standard unweighted support vector machine (SVM) classifier. The detection performance is evaluated using response receiver operating (ROC) curves and free-response receiver operating characteristic (FROC) curves. The proposed method obtained an area under the ROC curve of 0.8676, while the standard SVM obtained an area of 0.8268 for MC detection. For MC cluster detection, the proposed method obtained a high sensitivity of 92 % with a false-positive rate of 2.3 clusters/image, and it is also better than standard SVM with 4.7 false-positive clusters/image at the same sensitivity.

  6. A comparison of the accuracy of film-screen mammography, full-field digital mammography, and digital breast tomosynthesis

    International Nuclear Information System (INIS)

    Michell, M.J.; Iqbal, A.; Wasan, R.K.; Evans, D.R.; Peacock, C.; Lawinski, C.P.; Douiri, A.; Wilson, R.; Whelehan, P.

    2012-01-01

    Aim: To measure the change in diagnostic accuracy of conventional film-screen mammography and full-field digital mammography (FFDM) with the addition of digital breast tomosynthesis (DBT) in women recalled for assessment following routine screening. Materials and methods: Ethics approval for the study was granted. Women recalled for assessment following routine screening with screen-film mammography were invited to participate. Participants underwent bilateral, two-view FFDM and two-view DBT. Readers scored each lesion separately for probability of malignancy on screen-film mammography, FFDM, and then DBT. The scores were compared with the presence or absence of malignancy based on the final histopathology outcome. Results: Seven hundred and thirty-eight women participated (93.2% recruitment rate). Following assessment 204 (26.8%) were diagnosed as malignant (147 invasive and 57 in-situ tumours), 286 (37.68%) as benign, and 269 (35.4%) as normal. The diagnostic accuracy was evaluated by using receiving operating characteristic (ROC) and measurement of area under the curve (AUC). The AUC values demonstrated a significant (p = 0.0001) improvement in the diagnostic accuracy with the addition of DBT combined with FFDM and film-screen mammography (AUC = 0.9671) when compared to FFDM plus film-screen mammography (AUC = 0.8949) and film-screen mammography alone (AUC = 0.7882). The effect was significantly greater for soft-tissue lesions [AUC was 0.9905 with the addition of DBT and AUC was 0.9201 for FFDM with film-screen mammography combined (p = 0.0001)] compared to microcalcification [with the addition of DBT (AUC = 0.7920) and for FFDM with film-screen mammography combined (AUC = 0.7843; p = 0.3182)]. Conclusion: The addition of DBT increases the accuracy of mammography compared to FFDM and film-screen mammography combined and film-screen mammography alone in the assessment of screen-detected soft-tissue mammographic abnormalities.

  7. Mapping 3D breast lesions from full-field digital mammograms using subject-specific finite element models

    Science.gov (United States)

    García, E.; Oliver, A.; Diaz, O.; Diez, Y.; Gubern-Mérida, A.; Martí, R.; Martí, J.

    2017-03-01

    Patient-specific finite element (FE) models of the breast have received increasing attention due to the potential capability of fusing images from different modalities. During the Magnetic Resonance Imaging (MRI) to X-ray mammography registration procedure, the FE model is compressed mimicking the mammographic acquisition. Subsequently, suspicious lesions in the MRI volume can be projected into the 2D mammographic space. However, most registration algorithms do not provide the reverse information, avoiding to obtain the 3D geometrical information from the lesions localized in the mammograms. In this work we introduce a fast method to localize the 3D position of the lesion within the MRI, using both cranio-caudal (CC) and medio-lateral oblique (MLO) mammographic projections, indexing the tetrahedral elements of the biomechanical model by means of an uniform grid. For each marked lesion in the Full-Field Digital Mammogram (FFDM), the X-ray path from source to the marker is calculated. Barycentric coordinates are computed in the tetrahedrons traversed by the ray. The list of elements and coordinates allows to localize two curves within the MRI and the closest point between both curves is taken as the 3D position of the lesion. The registration errors obtained in the mammographic space are 9.89 +/- 3.72 mm in CC- and 8.04 +/- 4.68 mm in MLO-projection and the error in the 3D MRI space is equal to 10.29 +/- 3.99 mm. Regarding the uniform grid, it is computed spending between 0.1 and 0.7 seconds. The average time spent to compute the 3D location of a lesion is about 8 ms.

  8. Investigating compression failure mechanisms in composite laminates with a transparent fiberglass-epoxy birefringent materials

    Science.gov (United States)

    Shuart, M. J.; Williams, J. G.

    1984-01-01

    The response and failure of a + or - 45s class laminate was studied by transparent fiberglass epoxy composite birefringent material. The birefringency property allows the laminate stress distribution to be observed during the test and also after the test if permanent residual stresses occur. The location of initial laminate failure and of the subsequent failure propagation are observed through its transparency characteristics. Experimental results are presented.

  9. 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

  10. 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.

  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. Quantitative comparison of clustered microcalcifications in for-presentation and for-processing mammograms in full-field digital mammography.

    Science.gov (United States)

    Wang, Juan; Nishikawa, Robert M; Yang, Yongyi

    2017-07-01

    Mammograms acquired with full-field digital mammography (FFDM) systems are provided in both "for-processing'' and "for-presentation'' image formats. For-presentation images are traditionally intended for visual assessment by the radiologists. In this study, we investigate the feasibility of using for-presentation images in computerized analysis and diagnosis of microcalcification (MC) lesions. We make use of a set of 188 matched mammogram image pairs of MC lesions from 95 cases (biopsy proven), in which both for-presentation and for-processing images are provided for each lesion. We then analyze and characterize the MC lesions from for-presentation images and compare them with their counterparts in for-processing images. Specifically, we consider three important aspects in computer-aided diagnosis (CAD) of MC lesions. First, we quantify each MC lesion with a set of 10 image features of clustered MCs and 12 textural features of the lesion area. Second, we assess the detectability of individual MCs in each lesion from the for-presentation images by a commonly used difference-of-Gaussians (DoG) detector. Finally, we study the diagnostic accuracy in discriminating between benign and malignant MC lesions from the for-presentation images by a pretrained support vector machine (SVM) classifier. To accommodate the underlying background suppression and image enhancement in for-presentation images, a normalization procedure is applied. The quantitative image features of MC lesions from for-presentation images are highly consistent with that from for-processing images. The values of Pearson's correlation coefficient between features from the two formats range from 0.824 to 0.961 for the 10 MC image features, and from 0.871 to 0.963 for the 12 textural features. In detection of individual MCs, the FROC curve from for-presentation is similar to that from for-processing. In particular, at sensitivity level of 80%, the average number of false-positives (FPs) per image region is 9

  13. Validating Laser-Induced Birefringence Theory with Plasma Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cecilia [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cornell Univ., Ithaca, NY (United States)

    2015-09-02

    Intense laser beams crossing paths in plasma is theorized to induce birefringence in the medium, resulting from density and refractive index modulations that affect the polarization of incoming light. The goal of the associated experiment, conducted on Janus at Lawrence Livermore’s Jupiter Laser Facility, was to create a tunable laser-plasma waveplate to verify the relationship between dephasing angle and beam intensity, plasma density, plasma temperature, and interaction length. Interferometry analysis of the plasma channel was performed to obtain a density map and to constrain temperature measured from Thomson scattering. Various analysis techniques, including Fast Fourier transform (FFT) and two variations of fringe-counting, were tried because interferograms captured in this experiment contained unusual features such as fringe discontinuity at channel edges, saddle points, and islands. The chosen method is flexible, semi-automated, and uses a fringe tracking algorithm on a reduced image of pre-traced synthetic fringes. Ultimately, a maximum dephasing angle of 49.6° was achieved using a 1200 μm interaction length, and the experimental results appear to agree with predictions.

  14. Preliminary Sensorimotor and Cardiovascular Results from the Joint Russian/U.S. Pilot Field Test in Preparation for the Full Field Test

    Science.gov (United States)

    Reschke, M. F.; Kozlovskaya, I. B.; Tomilovskaya, E. S.; Bloomberg, J. J.; Platts, S. H.; Rukavishnikov, I. V.; Fomina, E. V.; Stenger, M. B.; Lee, S. M. C.; Wood, S. J.; hide

    2014-01-01

    Ongoing collaborative research efforts between NASA's Neuroscience and Cardiovascular Laboratories, and the Institute of Biomedical Problems' (IBMP) Sensory-Motor and Countermeasures Laboratories have been measuring functional sensorimotor, cardiovascular and strength responses following bed rest, dry immersion, short-duration (Space Shuttle) and long-duration (Mir and International Space Station [ISS]) space flights. While the unloading paradigms associated with dry immersion and bed rest does serve as acceptable flight analogs, testing of crew responses following the long-duration flights previously has not been possible until a minimum of 24 hours after landing. As a result, it is not possible to estimate the nonlinear trend of the early (the full impact of the decrements associated with long-duration flight. To overcome these limitations, both the Russian and U.S. programs have implemented testing at the landing site. By joint agreement, this research effort has been identified as the functional Field Test (FT). For practical reasons the FT has been divided into two phases: the full FT and a preliminary pilot version (PFT) of the FT that is reduced in both length and scope. The primary goal of this research is to determine functional abilities in long-duration space-flight crews beginning as soon after landing as possible (one to three immediate follow-up measurements on the day of landing. This goal has both sensorimotor and cardiovascular elements, including evaluations of NASA's new anti-orthostatic compression garment and the Russian Kentavr garment. Functional sensorimotor measurements will include, but are not limited to, assessing hand/eye coordination, egressing from a seated position, walking normally without falling, measuring of dynamic visual acuity, discriminating different forces generated with both the hands and legs, recovering from a fall, coordinated walking involving tandem heel-to-toe placement, and determining postural ataxia while standing

  15. Analyzing panel acoustic contributions toward the sound field inside the passenger compartment of a full-size automobile.

    Science.gov (United States)

    Wu, Sean F; Moondra, Manmohan; Beniwal, Ravi

    2015-04-01

    The Helmholtz equation least squares (HELS)-based nearfield acoustical holography (NAH) is utilized to analyze panel acoustic contributions toward the acoustic field inside the interior region of an automobile. Specifically, the acoustic power flows from individual panels are reconstructed, and relative contributions to sound pressure level and spectrum at any point of interest are calculated. Results demonstrate that by correlating the acoustic power flows from individual panels to the field acoustic pressure, one can correctly locate the panel allowing the most acoustic energy transmission into the vehicle interior. The panel on which the surface acoustic pressure amplitude is the highest should not be used as indicative of the panel responsible for the sound field in the vehicle passenger compartment. Another significant advantage of this HELS-based NAH is that measurements of the input data only need to be taken once by using a conformal array of microphones in the near field, and ranking of panel acoustic contributions to any field point can be readily performed. The transfer functions between individual panels of any vibrating structure to the acoustic pressure anywhere in space are calculated not measured, thus significantly reducing the time and effort involved in panel acoustic contributions analyses.

  16. Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors: Automated measurement development for full field digital mammography

    International Nuclear Information System (INIS)

    Fowler, E. E.; Sellers, T. A.; Lu, B.; Heine, J. J.

    2013-01-01

    Purpose: The Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors are used for standardized mammographic reporting and are assessed visually. This reporting is clinically relevant because breast composition can impact mammographic sensitivity and is a breast cancer risk factor. New techniques are presented and evaluated for generating automated BI-RADS breast composition descriptors using both raw and calibrated full field digital mammography (FFDM) image data.Methods: A matched case-control dataset with FFDM images was used to develop three automated measures for the BI-RADS breast composition descriptors. Histograms of each calibrated mammogram in the percent glandular (pg) representation were processed to create the new BR pg measure. Two previously validated measures of breast density derived from calibrated and raw mammograms were converted to the new BR vc and BR vr measures, respectively. These three measures were compared with the radiologist-reported BI-RADS compositions assessments from the patient records. The authors used two optimization strategies with differential evolution to create these measures: method-1 used breast cancer status; and method-2 matched the reported BI-RADS descriptors. Weighted kappa (κ) analysis was used to assess the agreement between the new measures and the reported measures. Each measure's association with breast cancer was evaluated with odds ratios (ORs) adjusted for body mass index, breast area, and menopausal status. ORs were estimated as per unit increase with 95% confidence intervals.Results: The three BI-RADS measures generated by method-1 had κ between 0.25–0.34. These measures were significantly associated with breast cancer status in the adjusted models: (a) OR = 1.87 (1.34, 2.59) for BR pg ; (b) OR = 1.93 (1.36, 2.74) for BR vc ; and (c) OR = 1.37 (1.05, 1.80) for BR vr . The measures generated by method-2 had κ between 0.42–0.45. Two of these measures were significantly

  17. Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors: Automated measurement development for full field digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, E. E.; Sellers, T. A.; Lu, B. [Department of Cancer Epidemiology, Division of Population Sciences, H. Lee Moffitt Cancer Center, Tampa, Florida 33612 (United States); Heine, J. J. [Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center, Tampa, Florida 33612 (United States)

    2013-11-15

    Purpose: The Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors are used for standardized mammographic reporting and are assessed visually. This reporting is clinically relevant because breast composition can impact mammographic sensitivity and is a breast cancer risk factor. New techniques are presented and evaluated for generating automated BI-RADS breast composition descriptors using both raw and calibrated full field digital mammography (FFDM) image data.Methods: A matched case-control dataset with FFDM images was used to develop three automated measures for the BI-RADS breast composition descriptors. Histograms of each calibrated mammogram in the percent glandular (pg) representation were processed to create the new BR{sub pg} measure. Two previously validated measures of breast density derived from calibrated and raw mammograms were converted to the new BR{sub vc} and BR{sub vr} measures, respectively. These three measures were compared with the radiologist-reported BI-RADS compositions assessments from the patient records. The authors used two optimization strategies with differential evolution to create these measures: method-1 used breast cancer status; and method-2 matched the reported BI-RADS descriptors. Weighted kappa (κ) analysis was used to assess the agreement between the new measures and the reported measures. Each measure's association with breast cancer was evaluated with odds ratios (ORs) adjusted for body mass index, breast area, and menopausal status. ORs were estimated as per unit increase with 95% confidence intervals.Results: The three BI-RADS measures generated by method-1 had κ between 0.25–0.34. These measures were significantly associated with breast cancer status in the adjusted models: (a) OR = 1.87 (1.34, 2.59) for BR{sub pg}; (b) OR = 1.93 (1.36, 2.74) for BR{sub vc}; and (c) OR = 1.37 (1.05, 1.80) for BR{sub vr}. The measures generated by method-2 had κ between 0.42–0.45. Two of these

  18. Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors: automated measurement development for full field digital mammography.

    Science.gov (United States)

    Fowler, E E; Sellers, T A; Lu, B; Heine, J J

    2013-11-01

    The Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors are used for standardized mammographic reporting and are assessed visually. This reporting is clinically relevant because breast composition can impact mammographic sensitivity and is a breast cancer risk factor. New techniques are presented and evaluated for generating automated BI-RADS breast composition descriptors using both raw and calibrated full field digital mammography (FFDM) image data. A matched case-control dataset with FFDM images was used to develop three automated measures for the BI-RADS breast composition descriptors. Histograms of each calibrated mammogram in the percent glandular (pg) representation were processed to create the new BR(pg) measure. Two previously validated measures of breast density derived from calibrated and raw mammograms were converted to the new BR(vc) and BR(vr) measures, respectively. These three measures were compared with the radiologist-reported BI-RADS compositions assessments from the patient records. The authors used two optimization strategies with differential evolution to create these measures: method-1 used breast cancer status; and method-2 matched the reported BI-RADS descriptors. Weighted kappa (κ) analysis was used to assess the agreement between the new measures and the reported measures. Each measure's association with breast cancer was evaluated with odds ratios (ORs) adjusted for body mass index, breast area, and menopausal status. ORs were estimated as per unit increase with 95% confidence intervals. The three BI-RADS measures generated by method-1 had κ between 0.25-0.34. These measures were significantly associated with breast cancer status in the adjusted models: (a) OR = 1.87 (1.34, 2.59) for BR(pg); (b) OR = 1.93 (1.36, 2.74) for BR(vc); and (c) OR = 1.37 (1.05, 1.80) for BR(vr). The measures generated by method-2 had κ between 0.42-0.45. Two of these measures were significantly associated with breast cancer

  19. Isochromate fringes simulation by Cassini-like curves for photoelastic analysis of birefringent crystals

    International Nuclear Information System (INIS)

    Rinaldi, D.; Pietroni, P.; Davi, F.

    2009-01-01

    In optically birefringent uniaxial and biaxial crystals, analyzed by plane polariscope, isochromate interference fringes can be observed. By means of the classical electromagnetic theory a Cassini-like analytical equation of the isochromate fringes, depending on the refraction indexes, has been obtained. The proposed analytical equation is a useful tool to evaluate the internal stress state, as it is related to the isochromate shapes owing to the induced variation of the refraction indexes. Uniaxial crystals can assume complex biaxial behaviour due to particular stress configurations. PbWO 4 (PWO) uniaxial scintillating crystals have been studied. The Cassini-like curves fit well experimental measurements in the case of uniaxial stress. In this research work, a simple model has been proved in the case of strong isochromate fringes distortion due to a stress gradient induced by the bending load. The model fits well the interference pattern, acquired experimentally. This study can pave the way for the quality control on scintillating crystals, used in the fields of high-energy detectors, security and biomedical applications, with complex internal stress state.

  20. A birefringent polarization modulator: Application to phase measurement in conoscopic interference patterns

    Science.gov (United States)

    Veiras, F. E.; Garea, M. T.; Perez, L. I.

    2016-04-01

    Conoscopic interferometry for crystal characterization is a very well-known technique with increasing applications in different fields of technology. The advantage of the scheme proposed here is the introduction of a polarization modulator that allows the recovery of the phase information contained in conoscopic interferograms. This represents a real advantage since the most relevant physical information of the sample under study is usually contained in the phase of the fringe pattern. Moreover, this technique works successfully even when there are no visible fringes. The setup employed is a simple conoscopic interferometer where the elements under study correspond to two birefringent crystal slabs and a commercial mica wave plate. It allows the crystals to be characterized and the wave plate retardance to be measured as a function of the angle of incidence. The modulator itself consists of a single tiltable crystal plate which, by means of phase shifting techniques, permits the recovery of a phase map for each sample. It is inexpensive and it can be easily calibrated, so it works with a wide range of phase shifting interferometry algorithms. We show that our scheme is easily adaptable to algorithms that require either a low or high amount of interferograms.

  1. Coupled thermal-optic effects and electrical modulation mechanism of birefringence crystal with Gaussian laser incidence

    International Nuclear Information System (INIS)

    Zhou Ji; He Zhi-Hong; Ma Yu; Dong Shi-Kui

    2015-01-01

    We study the Gaussian laser transmission in lithium niobate crystal (LiNbO 3 ) by using the finite element method to solve the electromagnetic field’s frequency domain equation and energy equation. The heat generated is identified by calculating the transmission loss of the electromagnetic wave in the birefringence crystal, and the calculated value of the heat generated is substituted into the energy equation. The electromagnetic wave’s energy losses induced by its multiple refractions and reflections along with the resulting physical property changes of the lithium niobate crystal are considered. Influences of ambient temperature and heat transfer coefficient on refraction and walk-off angles of O-ray and E-ray in the cases of different incident powers and crystal thicknesses are analyzed. The E-ray electrical modulation instances, in which the polarized light waveform is adjusted to the rated condition via an applied electrical field in the cases of different ambient temperatures and heat transfer coefficients, are provided to conclude that there is a correlation between ambient temperature and applied electrical field intensity and a correlation between surface heat transfer coefficient and applied electrical field intensity. The applicable electrical modulation ranges without crystal breakdown are proposed. The study shows that the electrical field-adjustable heat transfer coefficient range becomes narrow as the incident power decreases and wide as the crystal thickness increases. In addition, it is pointed out that controlling the ambient temperature is easier than controlling the heat transfer coefficient. The results of the present study can be used as a quantitative theoretical basis for removing the adverse effects induced by thermal deposition due to linear laser absorption in the crystal, such as depolarization or wave front distortion, and indicate the feasibility of adjusting the refractive index in the window area by changing the heat transfer

  2. Digital image processing for quantification through full flow field tracing (FFFT) in narrow geometries at low Reynolds numbers

    Science.gov (United States)

    Braun, M. J.; Batur, C.; Karavelakis, G.

    1988-01-01

    This paper introduces a computer based image processing technique to the field of nonintrusive velocity measurements in fluid mechanics. The method is presented with two alternatives: the first is involving intense interaction between the operator and the computer system; the second is a first generation artificial intelligence based system, where a set of initially imputed rules replaces the operator. The methods are applied to flow in narrow gaps.

  3. Reversible Luminescence Modulation upon an Electric Field on a Full Solid-State Device Based on Lanthanide Dimers.

    Science.gov (United States)

    Yi, Xiaohui; Shang, Jie; Pan, Liang; Tan, Hongwei; Chen, Bin; Liu, Gang; Huang, Gang; Bernot, Kevin; Guillou, Olivier; Li, Run-Wei

    2016-06-22

    Switching luminescence of lanthanide-based molecules through an external electric field is considered as a promising approach toward novel functional molecule-based devices. Classic routes use casted films and liquid electrolyte as media for redox reactions. Such protocol, even if efficient, is relatively hard to turn into an effective solid-state device. In this work, we explicitly synthesize lanthanide-based dimers whose luminescent behavior is affected by the presence of Cu(2+) ions. Excellent evaporability of the dimers and utilization of Cu(2+)-based solid-state electrolyte makes it possible to reproduce solution behavior at the solid state. Reversible modulation of Cu(2+) ions transport can be achieved by an electric field in a solid-state device, where lanthanide-related luminescence is driven by an electric field. These findings provide a proof-of-concept alternative approach for electrically driven modulation of solid-state luminescence and show promising potential for information storage media in the future.

  4. Historical sketches of Sandia National Laboratories nuclear field testing. Volume 1: Full discussion except for sensitive references

    International Nuclear Information System (INIS)

    Banister, J.R.

    1994-10-01

    This report contains historical sketches that cover the major activities of Sandia nuclear field testing, from early atmospheric shots until 1990. It includes a chronological overview followed by more complete discussions of atmospheric, high-altitude, underwater, cratering, and underground nuclear testing. Other activities related to nuclear testing and high-explosive tests are also described. A large number of references are cited for readers who wish to learn more about technical details. Appendices, written by several authors, provide more insight for a variety of special aspects of nuclear testing and related work. Two versions of this history were published: volume 1 has an unlimited distribution, and volume 2 has a limited distribution

  5. Study of one-dimensional nanolayered graded photonic crystal consisting of birefringent and dielectric materials

    Science.gov (United States)

    Kumar, Rajeev; Kumar, Dhananjay; Kushwaha, Angad S.; Srivastava, S. K.

    2018-02-01

    In the present paper, we have studied a comparison between dielectric-dielectric photonic crystal (PhC) and birefringent-dielectric PhC structure with, and without, gradation in the thickness of the layers of the proposed structure. Graded birefringent-dielectric PhC has a linear change in the thickness of the layers. With the help of the transfer matrix method, the proposed structures have been extensively investigated. It is found that photonic band gap (PBG) width and omnidirectional reflection band width has been widely enhanced, in graded birefringent-dielectric PhC structure as compared to the non-graded birefringent-dielectric PhC structure, for both TE and TM polarizations. We have also found that the gradation in the thickness of the birefringent layer is more effective, as compare the gradation in the thickness of the dielectric layer, for enhancement of reflection band width. The results obtained are quite good and thus, it may be widely used as broad band optical and omnidirectional reflector.

  6. Induced birefringence in optically isotropic glass by a short pulsed Nd:YAG laser

    Science.gov (United States)

    Deb, Paramita; Gupta, K. C.; Murali, C. G.; Dhareshwar, L. J.; Godwal, B. K.

    2006-10-01

    We have observed laser induced birefringence in optically isotropic glasses as well as in Nd:YAG crystal using polarized pulses of wavelength 1.06 µm and duration 100 ps with an intensity near 109 W cm-2. The laser used in the experiment was a Nd:YAG oscillator-amplifier system. The change in the material induced by the laser was not a permanent change but existed for as long as the laser pulse lasted. We observed conoscopic patterns when the laser was passed through glass or the Nd:YAG crystal. These patterns are typically seen when light is passed through birefringent materials kept between a polarizer and analyser. This observation immediately suggests that the glass or the crystal possesses optical birefringence. This birefringence is demonstrated in fused silica glass, Nd:glass and Nd:YAG crystal. The circular symmetric conoscopic patterns show that the optic axis is formed along the direction of laser propagation. The laser induced birefringence depended on the laser intensity and we characterized the magnitude of this change by measuring the output pulse at the end of the crossed polarizer.

  7. Development of full-field x-ray phase-tomographic microscope based on laboratory x-ray source

    Science.gov (United States)

    Takano, H.; Wu, Y.; Momose, A.

    2017-09-01

    An X-ray phase tomographic microscope that can quantitatively measure the refractive index of a sample in three dimensions with a high spatial resolution was developed by installing a Lau interferometer consisting of an absorption grating and a π/2 phase grating into the optics of an X-ray microscope. The optics comprises a Cu rotating anode X-ray source, capillary condenser optics, and a Fresnel zone plate for the objective. The microscope has two optical modes: a large-field-of-view mode (field of view: 65 μm x 65 μm) and a high-resolution mode (spatial resolution: 50 nm). Optimizing the parameters of the interferometer yields a self-image of the phase grating with 60% visibility. Through the normal fringe-scanning measurement, a twin phase image, which has an overlap of two phase image of opposite contrast with a shear distance much larger than system resolution, is generated. Although artifacts remain to some extent currently when a phase image is calculated from the twin phase image, this system can obtain high-spatial-resolution images resolving 50-nm structures. Phase tomography with this system has also been demonstrated using a phase object.

  8. Large-area full field x-ray differential phase-contrast imaging using 2D tiled gratings

    Science.gov (United States)

    Schröter, Tobias J.; Koch, Frieder J.; Kunka, Danays; Meyer, Pascal; Tietze, Sabrina; Engelhardt, Sabine; Zuber, Marcus; Baumbach, Tilo; Willer, Konstantin; Birnbacher, Lorenz; Prade, Friedrich; Pfeiffer, Franz; Reichert, Klaus-Martin; Hofmann, Andreas; Mohr, Jürgen

    2017-06-01

    Grating-based x-ray differential phase-contrast imaging (DPCI) is capable of acquiring information based on phase-shift and dark-field signal, in addition to conventional x-ray absorption-contrast. Thus DPCI gives an advantage to investigate composite materials with component wise similar absorption properties like soft tissues. Due to technological challenges in fabricating high quality gratings over a large extent, the field of view (FoV) of the imaging systems is limited to a grating area of a couple of square centimeters. For many imaging applications (e.g. in medicine), however, a FoV that ranges over several ten centimeters is needed. In this manuscript we propose to create large area gratings of theoretically any extent by assembling a number of individual grating tiles. We discuss the precision needed for alignment of each microstructure tile in order to reduce image artifacts and to preserve minimum 90% of the sensitivity obtainable with a monolithic grating. To achieve a reliable high precision alignment a semiautomatic assembly system consisting of a laser autocollimator, a digital microscope and a force sensor together with positioning devices was built. The setup was used to tile a first four times four analyzer grating with a size of 200 mm  ×  200 mm together with a two times two phase grating. First imaging results prove the applicability and quality of the tiling concept.

  9. A Dissipation Gap Method for full-field measurement-based identification of elasto-plastic material parameters

    KAUST Repository

    Blaysat, Benoît

    2012-05-18

    Using enriched data such as displacement fields obtained from digital image correlation is a pathway to the local identification of material parameters. Up to now, most of the identification techniques for nonlinear models are based on Finite Element Updating Methods. This article explains how an appropriate use of the Dissipation Gap Method can help in this context and be an interesting alternative to these classical techniques. The Dissipation Gap Methods rely on the concept of error in dissipation that has been used mainly for the verification of finite element simulations. We provide here an original application of these founding developments to the identification of material parameters for nonlinear behaviors. The proposed technique and especially the main technical keypoint of building the admissible fields are described in detail. The approach is then illustrated through the identification of heterogeneous isotropic elasto-plastic properties. The basic numerical features highlighted through these simple examples demonstrate this approach to be a promising tool for nonlinear identification. © 2012 John Wiley & Sons, Ltd.

  10. Characterization of the failure in Callovo-Oxfordian argillite under plane strain compression using full field measurements

    International Nuclear Information System (INIS)

    Besuelle, P.

    2012-01-01

    Document available in extended abstract form only. Failure by strain localization is commonly observed in geo-materials. Cracks are detected in Underground Research Laboratories (URL) on the walls of galleries (e.g., Andra in Meuse/Haute Marne laboratory, SCK-CEN in Mol), they have been induced by the stress relaxation that results from the excavation. The cracks represent material discontinuities which could impact the flow properties of the rock mass in some circumstances. Generally, experimental characterization of the localization in rocks is performed with classical axisymmetric triaxial compression tests. The effect of the confining pressure can be observed on several aspects: onset of localization, pattern of localization, porosity evolution inside bands or cracks aperture, grain scale mechanisms of deformation (e.g., [1]). However the history (time evolution) of the localization is not accessible because the observations are post-mortem. Strain field measurement and evolution in time of the strain field are particularly useful to study the strain localization (initiation of the deformation bands) and the post-localization regime. Such tools have been developed for soils (e.g., sand specimens in plane strain condition [2] or in triaxial conditions using X-ray tomography [3]). Similar developments for rocks are still difficult, especially because the pertinent confining pressure to reproduce in situ stresses are higher than for soils. We present here first results obtained in a new true triaxial apparatus that allows observation of the rock specimen under loading and especially the complex development of deformation bands and faults. As for [4] and [5], the three principal stresses are different. However, for selected tests discussed here, the intermediate stress is controlled in order to impose a plane strain condition (zero strain in this direction). Observation of a specimen under load is possible as one surface of the prismatic specimen, which is

  11. Summary report on close-coupled subsurface barrier technology: Initial field trials to full-scale demonstration

    International Nuclear Information System (INIS)

    Heiser, J.H.

    1997-09-01

    The primary objective of this project was to develop and demonstrate the installation and measure the performance of a close-coupled barrier for the containment of subsurface waste or contaminant migration. A close-coupled barrier is produced by first installing a conventional, low-cost, cement-grout containment barrier followed by a thin lining of a polymer grout. The resultant barrier is a cement-polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. The technology has matured from a regulatory investigation of the issues concerning the use of polymers to laboratory compatibility and performance measurements of various polymer systems to a pilot-scale, single column injection at Sandia to full-scale demonstration. The feasibility of the close-coupled barrier concept was proven in a full-scale cold demonstration at Hanford, Washington and then moved to the final stage with a full-scale demonstration at an actual remediation site at Brookhaven National Laboratory (BNL). At the Hanford demonstration the composite barrier was emplaced around and beneath a 20,000 liter tank. The secondary cement layer was constructed using conventional jet grouting techniques. Drilling was completed at a 45 degree angle to the ground, forming a cone-shaped barrier. The primary barrier was placed by panel jet-grouting with a dual-wall drill stem using a two part polymer grout. The polymer chosen was a high molecular weight acrylic. At the BNL demonstration a V-trough barrier was installed using a conventional cement grout for the secondary layer and an acrylic-gel polymer for the primary layer. Construction techniques were identical to the Hanford installation. This report summarizes the technology development from pilot- to full-scale demonstrations and presents some of the performance and quality achievements attained

  12. Summary report on close-coupled subsurface barrier technology: Initial field trials to full-scale demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Heiser, J.H. [Brookhaven National Lab., Upton, NY (United States). Environmental and Waste Technology Center; Dwyer, B. [Sandia National Lab., Albuquerque, NM (United States)

    1997-09-01

    The primary objective of this project was to develop and demonstrate the installation and measure the performance of a close-coupled barrier for the containment of subsurface waste or contaminant migration. A close-coupled barrier is produced by first installing a conventional, low-cost, cement-grout containment barrier followed by a thin lining of a polymer grout. The resultant barrier is a cement-polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. The technology has matured from a regulatory investigation of the issues concerning the use of polymers to laboratory compatibility and performance measurements of various polymer systems to a pilot-scale, single column injection at Sandia to full-scale demonstration. The feasibility of the close-coupled barrier concept was proven in a full-scale cold demonstration at Hanford, Washington and then moved to the final stage with a full-scale demonstration at an actual remediation site at Brookhaven National Laboratory (BNL). At the Hanford demonstration the composite barrier was emplaced around and beneath a 20,000 liter tank. The secondary cement layer was constructed using conventional jet grouting techniques. Drilling was completed at a 45{degree} angle to the ground, forming a cone-shaped barrier. The primary barrier was placed by panel jet-grouting with a dual-wall drill stem using a two part polymer grout. The polymer chosen was a high molecular weight acrylic. At the BNL demonstration a V-trough barrier was installed using a conventional cement grout for the secondary layer and an acrylic-gel polymer for the primary layer. Construction techniques were identical to the Hanford installation. This report summarizes the technology development from pilot- to full-scale demonstrations and presents some of the performance and quality achievements attained.

  13. Real-time full-field characterization of transient dissipative soliton dynamics in a mode-locked laser

    Science.gov (United States)

    Ryczkowski, P.; Närhi, M.; Billet, C.; Merolla, J.-M.; Genty, G.; Dudley, J. M.

    2018-04-01

    Dissipative solitons are remarkably localized states of a physical system that arise from the dynamical balance between nonlinearity, dispersion and environmental energy exchange. They are the most universal form of soliton that can exist, and are seen in far-from-equilibrium systems in many fields, including chemistry, biology and physics. There has been particular interest in studying their properties in mode-locked lasers, but experiments have been limited by the inability to track the dynamical soliton evolution in real time. Here, we use simultaneous dispersive Fourier transform and time-lens measurements to completely characterize the spectral and temporal evolution of ultrashort dissipative solitons as their dynamics pass through a transient unstable regime with complex break-up and collisions before stabilization. Further insight is obtained from reconstruction of the soliton amplitude and phase and calculation of the corresponding complex-valued eigenvalue spectrum. These findings show how real-time measurements provide new insights into ultrafast transient dynamics in optics.

  14. Full-field Measurements of Strain Localisation in Sandstone by Neutron Tomography and 3D-Volumetric Digital Image Correlation

    Science.gov (United States)

    Tudisco, E.; Hall, S. A.; Charalampidou, E. M.; Kardjilov, N.; Hilger, A.; Sone, H.

    Recent studies have demonstrated that the combination of x-ray tomography during triaxial tests (;in-situ; tests) and 3D- volumetric Digital Image Correlation (3D-DIC) can provide important insight into the mechanical behaviour and deformation processes of granular materials such as sand. The application of these tools to investigate the mechanisms of failure in rocks is also of obvious interest. However, the relevant applied confining pressures for triaxial testing on rocks are higher than those on sands and therefore stronger pressure containment vessels, i.e., made of thick metal walls, are required. This makes in-situ x-ray imaging of rock deformation during triaxial tests a challenge. One possible solution to overcome this problem is to use neutrons, which should better penetrate the metal-walls of the pressure vessels. In this perspective, this work assesses the capability of neutron tomography with 3D-DIC to measure deformation fields in rock samples. Results from pre- and post-deformation neutron tomography of a Bentheim sandstone sample deformed ex-situ at 40 MPa show that clear images of the internal structure can be achieved and utilised for 3D-DIC analysis to reveal the details of the 3D strain field. From these results the character of the localised deformation in the study sample can thus be described. Furthermore, comparison with analyses based on equivalent x-ray tomography imaging of the same sample confirms the effectiveness of the method in relation to the more established x-ray based approach.

  15. The GOODS UV Legacy Fields: A Full Census of Faint Star-Forming Galaxies at z~0.5-2

    Science.gov (United States)

    Oesch, Pascal

    2014-10-01

    Deep HST imaging has shown that the overall star formation density and UV light density at z>3 is dominated by faint, blue galaxies. Remarkably, very little is known about the equivalent galaxy population at lower redshifts. Understanding how these galaxies evolve across the epoch of peak cosmic star-formation is key to a complete picture of galaxy evolution. While we and others have been making every effort to use existing UV imaging data, a large fraction of the prior data were taken without post-flash and are not photometric. We now propose to obtain a robust legacy dataset for a complete census of faint star-forming galaxies at z~0.5-2, akin to what is achieved at z>3, using the unique capabilities of the WFC3/UVIS camera to obtain very deep UV imaging to 27.5-28.0 mag over the CANDELS Deep fields in GOODS North and South. We directly sample the FUV at z>~0.5 and we make these prime legacy fields for JWST with unique and essential UV/blue HST coverage. Together with the exquisite ancillary multi-wavelength data at high spatial resolution from ACS and WFC3/IR our program will result in accurate photometric redshifts for very faint sources and will enable a wealth of research by the community. This includes tracing the evolution of the FUV luminosity function over the peak of the star formation rate density from z~3 down to z~0.5, measuring the physical properties of sub-L* galaxies, and characterizing resolved stellar populations to decipher the build-up of the Hubble sequence from sub-galactic clumps. The lack of a future UV space telescope makes the acquisition of such legacy data imperative for the JWST era and beyond.

  16. Introduction to the level-set full field modeling of laths spheroidization phenomenon in α/β titanium alloys

    Directory of Open Access Journals (Sweden)

    Polychronopoulou D.

    2016-01-01

    Full Text Available Fragmentation of α lamellae and subsequent spheroidization of α laths in α/β titanium alloys occurring during and after deformation are well known phenomena. We will illustrate the development of a new finite element methodology to model them. This new methodology is based on a level set framework to model the deformation and the ad hoc simultaneous and/or subsequent interfaces kinetics. We will focus, at yet, on the modeling of the surface diffusion at the α/β phase interfaces and the motion by mean curvature at the α/α grain interfaces.

  17. Noise-Source Separation Using Internal and Far-Field Sensors for a Full-Scale Turbofan Engine

    Science.gov (United States)

    Hultgren, Lennart S.; Miles, Jeffrey H.

    2009-01-01

    Noise-source separation techniques for the extraction of the sub-dominant combustion noise from the total noise signatures obtained in static-engine tests are described. Three methods are applied to data from a static, full-scale engine test. Both 1/3-octave and narrow-band results are discussed. The results are used to assess the combustion-noise prediction capability of the Aircraft Noise Prediction Program (ANOPP). A new additional phase-angle-based discriminator for the three-signal method is also introduced.

  18. Guiding and birefringent properties of a hybrid PDMS/silica photonic crystal fiber

    Science.gov (United States)

    Markos, Christos; Vlachos, Kyriakos; Kakarantzas, George

    2011-02-01

    In this work, we demonstrate a highly birefringent (Hi-Bi) photonic crystal fiber (PCF) infiltrated with PDMS elastomer in order to enhance the sensitivity of the fiber to external temperature variations. Index guiding mechanism of the new PDMS/Silica structure and birefringent properties were investigated numerically and experimentally. We investigated the temperature dependance of birefringence from 20-120°C. For the particular design of Hi-Bi PCF, the cut-off operating wavelength of the hybrid fiber was found to be around 750 nm. We also experimentally demonstrate the effect of the elastomer inclusions to the polarization of the fiber. The sensitivity of the PDMS/Silica Hi-Bi fiber was found to be ~ 0.37 rad/K/cm for temperatures ranging from 20 to 80°C. The total length of the hybrid PCF examined was about 1.4 cm.

  19. Effect of salinity on the ultrasonic absorption and flow birefringence of microemulsions

    OpenAIRE

    Hirsch, E.; Debeauvais, F.; Candau, F.; Lang, J.; Zana, R.

    1984-01-01

    The behaviour of microemulsions made of toluene, brine, sodium dodecylsulfate and butanol has been investigated as a function of salinity by means of ultrasonic absorption and flow birefringence techniques. As the salinity is increased in the system, phase transitions from Winsor I → Winsor III and Winsor III → Winsor II occur at S1 = 5.5 and S2 = 8 g NaCl/100 g water respectively. At both S1 and S2 salinities, the flow birefringence exhibits a divergence which demonstrates the existence of a...

  20. A parameterization study for elastic VTI Full Waveform Inversion of hydrophone components: synthetic and North Sea field data examples

    KAUST Repository

    Guitton, Antoine

    2017-08-15

    Choosing the right parameterization to describe a transversely isotropic medium with a vertical symmetry axis (VTI) allows us to match the scattering potential of these parameters to the available data in a way that avoids potential tradeoff and focus on the parameters to which the data are sensitive. For 2-D elastic full waveform inversion in VTI media of pressure components and for data with a reasonable range of offsets (as with those found in conventional streamer data acquisition systems), assuming that we have a kinematically accurate NMO velocity (vnmo) and anellipticity parameter η (or horizontal velocity, vh) obtained from tomographic methods, a parameterization in terms of horizontal velocity vh, η and ε is preferred to the more conventional parameterization in terms of vh, δ and ε. In the vh, η, ε parameterization and for reasonable scattering angles (<60o), ε acts as a “garbage collector” and absorbs most of the amplitude discrepancies; between modeled and observed data, more so when density ρ and shear-wave velocity vs are not inverted for (a standard practice with streamer data). On the contrary, in the vv, δ, ε parameterization, ε is mostly sensitive to large scattering angles, leaving vv exposed to strong leakages from ρ mainly. There assertions will be demonstrated on the synthetic Marmousi II as well as a North Sea OBC dataset, where inverting for the horizontal velocity rather than the vertical velocity yields more accurate models and migrated images.

  1. 3D elastic full waveform inversion using P-wave excitation amplitude: Application to OBC field data

    KAUST Repository

    Oh, Juwon

    2017-12-05

    We propose an efficient elastic full waveform inversion (FWI) based on the P-wave excitation amplitude (maximum energy arrival) approximation in the source wavefields. Because, based on the P-wave excitation approximation (ExA), the gradient direction is approximated by the cross-correlation of source and receiver wavefields at only excitation time, it estimates the gradient direction faster than its conventional counterpart. In addition to this computational speedup, the P-wave excitation approximation automatically ignores SP and SS correlations in the approximated gradient direction. In elastic FWI for ocean bottom cable (OBC) data, the descent direction for the S-wave velocity is often degraded by undesired long-wavelength features from the SS correlation. For this reason, the P-wave excitation approach increases the convergence rate of multi-parameter FWI compared to the conventional approach. The modified 2D Marmousi model with OBC acquisition is used to verify the differences between the conventional method and ExA. Finally, the feasibility of the proposed method is demonstrated on a real OBC data from North Sea.

  2. 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.

  3. Genetic variation in carbon isotope discrimination and its relationship to growth under field conditions in full-sib families of Picea mariana

    Science.gov (United States)

    Lawrence B. Flanagan; Kurt H. Johnsen

    1995-01-01

    Measurements of the stable carbon isotope composition of leaf tissue were made on Picea mariana (Mill.) B.S.P. trees from four full-sib families grown on three different field sites at the Petawawa National Forestry Institute, Ontario, Canada. The four families chosen exhibited genetic variation for growth characteristics. Genetic...

  4. A Fault-Tolerant Parallel Structure of Single-Phase Full-Bridge Rectifiers for a Wound-Field Doubly Salient Generator

    DEFF Research Database (Denmark)

    Chen, Zhihui; Chen, Ran; Chen, Zhe

    2013-01-01

    The fault-tolerance design is widely adopted for high-reliability applications. In this paper, a parallel structure of single-phase full-bridge rectifiers (FBRs) (PS-SPFBR) is proposed for a wound-field doubly salient generator. The analysis shows the potential fault-tolerance capability of the PS...

  5. Electric Field Gradients of Light Impurities in TiO{sub 2} Calculated by the Full Potential KKR Green's Function Method

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, M., E-mail: agura@phys.sci.osaka-u.ac.jp; Akai, H. [Osaka University, Department of Physics, Graduate School of Science (Japan)

    2004-11-15

    The electric field gradients (EFGs) of B, N, O and Na in TiO{sub 2} were calculated by the full potential Korringa-Kohn-Rostoker (KKR) Greens function method in the framework of the density functional theory. The agreement with the experiments was much improved from the previous calculations that were based on the muffin-tin potential model.

  6. 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...

  7. 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

    of the circular cladding confines most of the power in the fiber-core. The fiber structure reported in this letter exhibits simultaneously ultrahigh modal birefringence of 7.5 × 10−2 and a very low effective absorption loss of 0.07 cm−1 for y-polarization mode at an operating frequency of 1 THz. It is highly...

  8. Conoscopic evaluation of the birefringence of gradient-index lenses: infidelity sources.

    Science.gov (United States)

    Tentori, Diana; Camacho, Javier

    2002-12-01

    Gradient-index lenses are samples whose special characteristics must be taken into account to design the optical polariscopes that can be applied in the evaluation of their birefringence. We discuss the main infidelity sources that modify the conoscopic patterns when a traditional polariscopic setup is used.

  9. Conoscopic evaluation of the birefringence of gradient-index lenses: infidelity sources

    Science.gov (United States)

    Tentori, Diana; Camacho, Javier

    2002-12-01

    Gradient-index lenses are samples whose special characteristics must be taken into account to design the optical polariscopes that can be applied in the evaluation of their birefringence. We discuss the main infidelity sources that modify the conoscopic patterns when a traditional polariscopic setup is used.

  10. 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

  11. Low-cost and easy to setup experiment to deter-mine birefringence ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 2. Birefringence of Mica. Sarmistha Sahu. Classroom Volume 15 Issue 2 February 2010 pp 165-169 ... Author Affiliations. Sarmistha Sahu1. Department of Physics, Maharani Lakshmi Ammani College for Women, Bangalore 560 012, India.

  12. Artificial high birefringence in all-dielectric gradient grating for broadband terahertz waves.

    Science.gov (United States)

    Chen, Meng; Fan, Fei; Xu, Shi-Tong; Chang, Sheng-Jiang

    2016-12-09

    Subwavelength dielectric gratings are widely applied in the phase and polarization manipulation of light. However, the dispersion of the normal dielectric gratings is not flat while their birefringences are not enough in the THz regime. In this paper, we have fabricated two all-dielectric gratings with gradient grids in the THz regime, of which artificial birefringence is much larger than that of the equal-grid dielectric grating demonstrated by both experiments and simulations. The transmission and dispersion characteristics are also improved since the gradient grids break the periodicity of grating lattices as a chirp feature. From 0.6-1.4 THz, a broadband birefringence reaches 0.35 with a low dispersion and good linearity of phase shift, and the maximum phase shift is 1.4π. Furthermore, these gradient gratings are applied as half-wave plates and realize a linear polarization conversion with a conversion rate over 99%, also much higher than the equal-grid gratings. These gradient gratings show great advantages compared to the periodic gratings and provide a new way in the designing of artificial birefringence material.

  13. Full-field mapping of internal strain distribution in red sandstone specimen under compression using digital volumetric speckle photography and X-ray computed tomography

    Directory of Open Access Journals (Sweden)

    Lingtao Mao

    2015-04-01

    Full Text Available It is always desirable to know the interior deformation pattern when a rock is subjected to mechanical load. Few experimental techniques exist that can represent full-field three-dimensional (3D strain distribution inside a rock specimen. And yet it is crucial that this information is available for fully understanding the failure mechanism of rocks or other geomaterials. In this study, by using the newly developed digital volumetric speckle photography (DVSP technique in conjunction with X-ray computed tomography (CT and taking advantage of natural 3D speckles formed inside the rock due to material impurities and voids, we can probe the interior of a rock to map its deformation pattern under load and shed light on its failure mechanism. We apply this technique to the analysis of a red sandstone specimen under increasing uniaxial compressive load applied incrementally. The full-field 3D displacement fields are obtained in the specimen as a function of the load, from which both the volumetric and the deviatoric strain fields are calculated. Strain localization zones which lead to the eventual failure of the rock are identified. The results indicate that both shear and tension are contributing factors to the failure mechanism.

  14. Full splitting of the first zero-field steps in the I-V curve of Josephson junctions of intermediate length

    International Nuclear Information System (INIS)

    Hansen, J.B.; Divin, Y.Y.; Mygind, J.

    1986-01-01

    We report on the observation of full splitting of the first zero-field steps in the I-V curves of Josephson transmission lines of intermediate length Lroughly-equal(3--5)lambda/sub J/, where lambda/sub J/ is the Josephson penetration length. We study in detail how this splitting of the step into two branches depends on the temperature of the junction and on a weak applied magnetic field. We relate the splitting to excitations in the junctions whose behavior is described by the perturbed Sine-Gordon equation

  15. Full splitting of the first zero-field steps in the I-V curve of Josephson junctions of intermediate length

    DEFF Research Database (Denmark)

    Hansen, Jørn Bindslev; Divin, Yu. Ya.; Mygind, Jesper

    1986-01-01

    We report on the observation of full splitting of the first zero-field steps in the I-V curves of Josephson transmission lines of intermediate length L≊(3–5)λJ, where λJ is the Josephson penetration length. We study in detail how this splitting of the step into two branches depends...... on the temperature of the junction and on a weak applied magnetic field. We relate the splitting to excitations in the junctions whose behavior is described by the perturbed sine-Gordon equation....

  16. Highly sensitive distributed birefringence measurements based on a two-pulse interrogation of a dynamic Brillouin grating

    Science.gov (United States)

    Soto, Marcelo A.; Denisov, Andrey; Angulo-Vinuesa, Xabier; Martin-Lopez, Sonia; Thévenaz, Luc; Gonzalez-Herraez, Miguel

    2017-04-01

    A method for distributed birefringence measurements is proposed based on the interference pattern generated by the interrogation of a dynamic Brillouin grating (DBG) using two short consecutive optical pulses. Compared to existing DBG interrogation techniques, the method here offers an improved sensitivity to birefringence changes thanks to the interferometric effect generated by the reflections of the two pulses. Experimental results demonstrate the possibility to obtain the longitudinal birefringence profile of a 20 m-long Panda fibre with an accuracy of 10-8 using 16 averages and 30 cm spatial resolution. The method enables sub-metric and highly-accurate distributed temperature and strain sensing.

  17. Use of retinal nerve fiber layer birefringence as an addition to absorption in retinal scanning for biometric purposes

    Science.gov (United States)

    Agopov, Mikael; Gramatikov, Boris I.; Wu, Yi-Kai; Irsch, Kristina; Guyton, David L.

    2008-03-01

    We built a device sensitive to the birefringence of the retinal nerve fiber layer for biometric purposes. A circle of 20° diameter on the retina was scanned around the optic disk with a spot of light from a 785 nm laser diode. The nonbirefringent blood vessels indenting or displacing the retinal nerve fiber layer were seen as “blips” in the measured birefringence-derived signal. For comparison, the reflection-absorption signature of the blood vessel pattern in the scanned circle was also measured. The birefringence-derived signal proved to add useful information to the reflectance-absorption signature for retinal biometric scanning.

  18. Evaluation of patient dose saving in grid-less x-ray mammography acquisition compared with full field digital mammography (FFDMG) acquisition

    DEFF Research Database (Denmark)

    Abdi, Ahmed Jibril; Mussmann, Bo Redder

    2017-01-01

    Purpose: To investigate the patient radiation dose saving of grid-less X-ray mammography acquisitions compared with conventional full-field digital X-ray mammography (FFDMG). Methods and materials: The Siemens Inspiration MAMMOMAT PRIME system with Software Based Scatter Correction (SBSC) was used...... to investigate the dose saving in grid-less acquisition compared with conventional full-field digital mammography (FFDMG) acquisitions. A Piranha 657 was used to measure the entrance exposure. The entrance exposure was directly measured on different PMMA thicknesses of 20-70mm in steps of 10mm. The PMMA block...... thicknesses were then converted to an equivalent compressed breast tissue thicknesses. The average glandular dose (AGD) is calculated. Results: Dose reduction in both the directly measured entrance exposure and the calculated AGD is between 13% and 32% in the grid-less mammography acquisition. The contrast...

  19. Role of field testing and shaking table test on full scale structure for NPP seismic-safety, and its relation to computational mechanics

    International Nuclear Information System (INIS)

    Shibata, Heki

    1988-01-01

    Field testing on the dynamic behavior of actual structures is significant for the seismic safety of nuclear power plants. For their mechanical components and piping systems, the full scale testings are also important as well as the in-situ test of buildings. In general, it is often observed that they don't behave as that of analytical model for the design. This article tries to discuss how such discrepancy is occurring, and how to overcome it. (author)

  20. A novel mosaicking algorithm for in vivo full-field thickness mapping of the human tympanic membrane using low coherence interferometry (Conference Presentation)

    Science.gov (United States)

    Pande, Paritosh; Shelton, Ryan L.; Monroy, Guillermo L.; Nolan, Ryan M.; Boppart, Stephen A.

    2016-02-01

    Tympanic membrane (TM) thickness can provide crucial information for diagnosing several middle ear pathologies. An imaging system integrating low coherence interferometry (LCI) with the standard video otoscope has been shown as a promising tool for quantitative assessment of in-vivo TM thickness. The small field-of-view (FOV) of TM surface images acquired by the combined LCI-otoscope system, however, makes the spatial registration of the LCI imaging sites and their location on the TM difficult to achieve. It is therefore desirable to have a tool that can map the imaged points on to an anatomically accurate full-field surface image of the TM. To this end, we propose a novel automated mosaicking algorithm for generating a full-field surface image of the TM with co-registered LCI imaging sites from a sequence of multiple small FOV images and corresponding LCI data. Traditional image mosaicking techniques reported in the biomedical literature, mostly for retinal imaging, are not directly applicable to TM image mosaicking because unlike retinal images, which have several distinctive features, TM images contain large homogeneous areas lacking in sharp features. The proposed algorithm overcomes these challenges of TM image mosaicking by following a two-step approach. In the first step, a coarse registration based on the correlation of gross image features is performed. Subsequently, in the second step, the coarsely registered images are used to perform a finer intensity-based co-registration. The proposed algorithm is used to generate, for the first time, full-field thickness distribution maps of in-vivo human TMs.

  1. Physical optics and full-wave simulations of transmission of electromagnetic fields through electrically large planar meta-sheets

    Directory of Open Access Journals (Sweden)

    E. Öziş

    2017-09-01

    Full Text Available Ultra-thin metamaterials, called meta-surfaces or meta-sheets, open up new opportunities in designing microwave radomes, including an improved transmission over a broader range of antenna scan angles, tailorable and reconfigurable frequency bands, polarization transformations, one-way transmission and switching ability. The smallness of the unit cells combined with the large electrical size of microwave radomes significantly complicates full-wave numerical simulations as a very fine sampling over an electrically large area is required. Physical optics (PO can be used to approximately describe transmission through the radome in terms of the homogenized transmission coefficient of the radome wall. This paper presents the results of numerical simulations of electromagnetic transmission through planar meta-sheets (infinite and circularly shaped obtained by using a full-wave electromagnetic field simulator and a PO-based solution.

  2. SANS, SAXS, rheology and birefringence-strengths and weaknesses in probing phase behaviour of a diblock copolymer

    DEFF Research Database (Denmark)

    Vigild, Martin Etchells; Eskimergen, Rüya; Mortensen, Kell

    2004-01-01

    Asymmetrically composed diblock copolymers exhibit multiphase behaviour and transit the lamellae, gyroid and hexagonal cylindrical phases before reaching the order–disorder temperature, TODT. During a heating experiment towards TODT we observe that birefringence measurements are more sensitive th...

  3. Vapor Sensor Realized in an Ultracompact Polarization Interferometer Built of a Freestanding Porous-Silicon Form Birefringent Film

    National Research Council Canada - National Science Library

    O, Beom-Hoan; Liu, Rong; Li, Yang Y; Sailor, Michael J; Fainman, Yeshaiahu

    2005-01-01

    .... The simulation accurately predicts the polarization interference signal, which is used to estimate the effective refractive indexes characterizing the form birefringence of a porous-silicon film with 0.001 accuracy...

  4. Dual-cladding high-birefringence and high-nonlinearity photonic crystal fiber with As2S3 core

    Science.gov (United States)

    Zhang, Xuedian; He, Menghui; Chang, Min; Chen, Hui; Chen, Nan; Qi, Ningning; Yuan, Manman; Qin, Xiaofei

    2018-03-01

    A novel dual-cladding photonic crystal fiber (PCF) with elliptical As2S3 core has been proposed to obtain high-birefringence and high-nonlinearity in PCFs. As2S3 has a high refractive index and a high nonlinear refractive index, as a result, it has a desired application on strengthening birefringence and nonlinearity. Then outer cladding of the PCF contains a hexagonal array of circular air holes. A circular array of circular air holes is introduced near the core as the inner cladding. We find that inner cladding could heighten birefringence and nonlinearity obviously. The simulation results show that the birefringence is as high as 0.307 at a wavelength of 1550 nm, and the nonlinearities of X- and Y-polarized reach 28660 km-1 W-1 and 38080 km-1 W-1 at the same wavelength, respectively.

  5. 3-D TECATE/BREW: Thermal, stress, and birefringent ray-tracing codes for solid-state laser design

    Science.gov (United States)

    Gelinas, R. J.; Doss, S. K.; Nelson, R. G.

    1994-07-01

    This report describes the physics, code formulations, and numerics that are used in the TECATE (totally Eulerian code for anisotropic thermo-elasticity) and BREW (birefringent ray-tracing of electromagnetic waves) codes for laser design. These codes resolve thermal, stress, and birefringent optical effects in 3-D stationary solid-state systems. This suite of three constituent codes is a package referred to as LASRPAK.

  6. Estimates of peak electric fields induced by Transcranial magnetic stimulation in pregnant women as patients using an FEM full-body model.

    Science.gov (United States)

    Yanamadala, J; Noetscher, G M; Makarov, S N; Pascual-Leone, A

    2017-07-01

    Transcranial magnetic stimulation (TMS) for treatment of depression during pregnancy is an appealing alternative to fetus-threatening drugs. However, no studies to date have been performed that evaluate the safety of TMS for a pregnant mother patient and her fetus. A full-body FEM model of a pregnant woman with about 100 tissue parts has been developed specifically for the present study. This model allows accurate computations of induced electric field in every tissue given different locations of a shape-eight coil, a biphasic pulse, common TMS pulse durations, and using different values of the TMS intensity measured in SMT (Standard Motor Threshold) units. Our simulation results estimate the maximum peak values of the electric field in the fetal area for every fetal tissue separately and for the TMS intensity of one SMT unit.

  7. Full-field fan-beam x-ray fluorescence computed tomography system design with linear-array detectors and pinhole collimation: a rapid Monte Carlo study

    Science.gov (United States)

    Zhang, Siyuan; Li, Liang; Li, Ruizhe; Chen, Zhiqiang

    2017-11-01

    We present the design concept and initial simulations for a polychromatic full-field fan-beam x-ray fluorescence computed tomography (XFCT) device with pinhole collimators and linear-array photon counting detectors. The phantom is irradiated by a fan-beam polychromatic x-ray source filtered by copper. Fluorescent photons are stimulated and then collected by two linear-array photon counting detectors with pinhole collimators. The Compton scatter correction and the attenuation correction are applied in the data processing, and the maximum-likelihood expectation maximization algorithm is applied for the image reconstruction of XFCT. The physical modeling of the XFCT imaging system was described, and a set of rapid Monte Carlo simulations was carried out to examine the feasibility and sensitivity of the XFCT system. Different concentrations of gadolinium (Gd) and gold (Au) solutions were used as contrast agents in simulations. Results show that 0.04% of Gd and 0.065% of Au can be well reconstructed with the full scan time set at 6 min. Compared with using the XFCT system with a pencil-beam source or a single-pixel detector, using a full-field fan-beam XFCT device with linear-array detectors results in significant scanning time reduction and may satisfy requirements of rapid imaging, such as in vivo imaging experiments.

  8. Multiple scattering of polarized light in birefringent slab media: experimental verifications and simulations.

    Science.gov (United States)

    Otsuki, Soichi

    2018-02-01

    The effective scattering Mueller matrices were measured for backward and forward scattering by applying a narrow polarized light on a polyacrylamide slab gel, which was strained vertically to generate birefringence inside. Monte Carlo simulations were performed in conditions that were the same as possible. The measured and simulated matrices were simplified to the reduced ones. They agreed well in both original and reduced forms. While they approximately take reciprocal forms for backward scattering, they approximately satisfy matrix forms that correspond to a reciprocal position of the mirror image for forward scattering. The reduced matrices were factorized by the Lu-Chipman polar decomposition to obtain the polarization parameters. The polarization parameters were in good agreement between the measurement and simulation and showed characteristic features of anisotropic slab media with a birefringence axis parallel to the slab surface.

  9. 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

  10. Polarized light imaging of birefringence and diattenuation at high resolution and high sensitivity

    International Nuclear Information System (INIS)

    Mehta, Shalin B; Shribak, Michael; Oldenbourg, Rudolf

    2013-01-01

    Polarized light microscopy provides unique opportunities for analyzing the molecular order in man-made and natural materials, including biological structures inside living cells, tissues, and whole organisms. 20 years ago, the LC-PolScope was introduced as a modern version of the traditional polarizing microscope enhanced by liquid crystal devices for the control of polarization, and by electronic imaging and digital image processing for fast and comprehensive image acquisition and analysis. The LC-PolScope is commonly used for birefringence imaging, analyzing the spatial and temporal variations of the differential phase delay in ordered and transparent materials. Here we describe an alternative use of the LC-PolScope for imaging the polarization dependent transmittance of dichroic materials. We explain the minor changes needed to convert the instrument between the two imaging modes, discuss the relationship between the quantities measured with each instrument, and touch on the physical connection between refractive index, birefringence, transmittance, diattenuation, and dichroism. (special issue article)

  11. 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.

  12. 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)

  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. The Nonlinear Changes of Temperature Response Birefringence of Side-Hole Fiber

    Science.gov (United States)

    Wang, Ning; Fu, Jianbo; Li, Dailin; Zhu, Huafeng; Wang, Tao

    2017-10-01

    For deeply investigate the birefringence responding of side-hole fiber caused by temperature, the response performance are analyzed by finite element method and elastic-optic theory, especially the nonlinear changes. The simulation results showed that the response birefringence is linear with temperature no matter how the geometry changed, but the response sensitivity is nonlinear with geometry parameters. The hole radius and hole-core distance both have their limit value to get obvious temperature sensitivity. Large hole radius and small hole-core distance is good to get high response sensitivity. Furthermore some interesting results are discussed about the response sensitivity changed with the square value of hole-core separation angle. The sensitivity is nonlinear with the square of hole-core separation angle for temperature, which is different to pressure response sensitivity.

  15. Evaluation of polycarbonate substrate hologram recording medium regarding implication of birefringence and thermal expansion

    Science.gov (United States)

    Toishi, Mitsuru; Tanaka, Tomiji; Fukumoto, Atsushi; Sugiki, Mikio; Watanabe, Kenjiro

    2007-02-01

    In this paper, we evaluate photopolymer media using a polycarbonate (PC) substrate. In holographic data storage medium, substrates that sandwich the photopolymer material are needed to protect the photopolymer material against exogenous shock and open air. An optical glass such as BK-7 is normally used as a substrate, but a PC substrate has a cost advantage and is easy to fabricate compared with optical glass. For holographic recording and reading, however, the high birefringence and high thermal expansion of a PC substrate are significant problems. First, we analyze the degree of degradation of output power by the polarization change and estimate the threshold value of birefringence to record hologram normally. Next, we estimate the temperature tolerance of hologram readout with polycarbonate substrate hologram medium. These analyses results indicate the possible usage of the PC substrate as holographic recording media.

  16. 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.

  17. 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.

  18. Brain refractive index measured in vivo with high-NA defocus-corrected full-field OCT and consequences for two-photon microscopy.

    Science.gov (United States)

    Binding, Jonas; Ben Arous, Juliette; Léger, Jean-François; Gigan, Sylvain; Boccara, Claude; Bourdieu, Laurent

    2011-03-14

    Two-photon laser scanning microscopy (2PLSM) is an important tool for in vivo tissue imaging with sub-cellular resolution, but the penetration depth of current systems is potentially limited by sample-induced optical aberrations. To quantify these, we measured the refractive index n' in the somatosensory cortex of 7 rats in vivo using defocus optimization in full-field optical coherence tomography (ff-OCT). We found n' to be independent of imaging depth or rat age. From these measurements, we calculated that two-photon imaging beyond 200 µm into the cortex is limited by spherical aberration, indicating that adaptive optics will improve imaging depth.

  19. Trace Element Mapping of a Biological Specimen by a Full-Field X-ray Fluorescence Imaging Microscope with a Wolter Mirror

    International Nuclear Information System (INIS)

    Hoshino, Masato; Yamada, Norimitsu; Ishino, Toyoaki; Namiki, Takashi; Watanabe, Norio; Aoki, Sadao

    2007-01-01

    A full-field X-ray fluorescence imaging microscope with a Wolter mirror was applied to the element mapping of alfalfa seeds. The X-ray fluorescence microscope was built at the Photon Factory BL3C2 (KEK). X-ray fluorescence images of several growing stages of the alfalfa seeds were obtained. X-ray fluorescence energy spectra were measured with either a solid state detector or a CCD photon counting method. The element distributions of iron and zinc which were included in the seeds were obtained using a photon counting method

  20. 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)

  1. Semiconductor laser with a birefringent external cavity for information systems with wavelength division multiplexing

    Energy Technology Data Exchange (ETDEWEB)

    Paranin, V D; Matyunin, S A; Tukmakov, K N [S.P. Korolev Samara State Aerospace University, Samara (Russian Federation)

    2013-10-31

    The spectrum of a semiconductor laser with a birefringent external Gires – Tournois cavity is studied. The generation of two main laser modes corresponding to the ordinary and extraordinary wave resonances is found. It is shown that the radiation spectrum is controlled with a high energy efficiency without losses for spectral filtration. The possibility of using two-mode lasing in optical communication systems with wavelength division multiplexing is shown. (control of laser radiation parameters)

  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. X-ray absorption spectroscopy by full-field X-ray microscopy of a thin graphite flake: Imaging and electronic structure via the carbon K-edge

    Directory of Open Access Journals (Sweden)

    Carla Bittencourt

    2012-04-01

    Full Text Available We demonstrate that near-edge X-ray-absorption fine-structure spectra combined with full-field transmission X-ray microscopy can be used to study the electronic structure of graphite flakes consisting of a few graphene layers. The flake was produced by exfoliation using sodium cholate and then isolated by means of density-gradient ultracentrifugation. An image sequence around the carbon K-edge, analyzed by using reference spectra for the in-plane and out-of-plane regions of the sample, is used to map and spectrally characterize the flat and folded regions of the flake. Additional spectral features in both π and σ regions are observed, which may be related to the presence of topological defects. Doping by metal impurities that were present in the original exfoliated graphite is indicated by the presence of a pre-edge signal at 284.2 eV.

  4. Novel laser machining of optical fibers for long cavities with low birefringence.

    Science.gov (United States)

    Takahashi, Hiroki; Morphew, Jack; Oručević, Fedja; Noguchi, Atsushi; Kassa, Ezra; Keller, Matthias

    2014-12-15

    We present a novel method of machining optical fiber surfaces with a CO₂ laser for use in Fiber-based Fabry-Perot Cavities (FFPCs). Previously FFPCs were prone to large birefringence and limited to relatively short cavity lengths (≤ 200 μm). These characteristics hinder their use in some applications such as cavity quantum electrodynamics with trapped ions. We optimized the laser machining process to produce large, uniform surface structures. This enables the cavities to achieve high finesse even for long cavity lengths. By rotating the fibers around their axis during the laser machining process the asymmetry resulting from the laser's transverse mode profile is eliminated. Consequently we are able to fabricate fiber mirrors with a high degree of rotational symmetry, leading to remarkably low birefringence. Through measurements of the cavity finesse over a range of cavity lengths and the polarization dependence of the cavity linewidth, we confirmed the quality of the produced fiber mirrors for use in low-birefringence FFPCs.

  5. Collagen birefringence assessment in heart chordae tendineae through PS-OCT

    Science.gov (United States)

    Real, Eusebio; Revuelta, José M.; González-Vargas, Nieves; Pontón, Alejandro; Calvo-Díez, Marta; López-Higuera, José M.; Conde, Olga M.

    2017-02-01

    Degenerative mitral regurgitation is a serious and frequent human heart valve disease. Malfunctioning of this valve brings the left-sided heart through a significant increase of pressure and volume overload. Severe degenerative mitral incompetence generally requires surgical repair or valve replacement with a bioprosthesis or mechanical heart valve. Degenerative disease affects the leaflets or/and the chordae tendineae, which link both leaflets to the papillary muscles. During mitral valve surgical repair, reconstruction of the valve leaflets, annulus and chordae are provided to prevent postoperative recurrence of valve regurgitation. The operative evaluation of the diseased and apparently normal chordae tendineae mainly depends of the surgeońs experience, without any other objective diagnosis tool. In this work, PS-OCT (Polarization Sensitive-Optical Coherence Tomography) is applied for the first time to evaluate the pathological condition of human chordae coming from the mitral valve. It consists on a prospective study to test the viability of this technique for the evaluation of the collagen core of chords. This core presents a strong birefringence due to the longitudinal and organized arrangement of its collagen bundles. Different densities and organizations of the collagen core translate into different birefringence indicators whose measurement become an objective marker of the core structure. Ex-vivo mitral degenerative chordae tendineae have been analyzed with PS-OCT. Intensity OCT is used to obtain complementary morphological information of the chords. Birefringence results correlate with the previously reported values for human tendinous tissue.

  6. Transient magnetic birefringence for determining magnetic nanoparticle diameters in dense, highly light scattering media

    Science.gov (United States)

    Köber, Mariana; Moros, Maria; Grazú, Valeria; de la Fuente, Jesus M.; Luna, Mónica; Briones, Fernando

    2012-04-01

    The increasing use of biofunctionalized magnetic nanoparticles in biomedical applications calls for further development of characterization tools that allow for determining the interactions of the nanoparticles with the biological medium in situ. In cell-incubating conditions, for example, nanoparticles may aggregate and serum proteins adsorb on the particles, altering the nanoparticles’ performance and their interaction with cell membranes. In this work we show that the aggregation of spherical magnetite nanoparticles can be detected with high sensitivity in dense, highly light scattering media by making use of magnetically induced birefringence. Moreover, the hydrodynamic particle diameter distribution of anisometric nanoparticle aggregates can be determined directly in these media by monitoring the relaxation time of the magnetically induced birefringence. As a proof of concept, we performed measurements on nanoparticles included in an agarose gel, which scatters light in a similar way as a more complex biological medium but where particle-matrix interactions are weak. Magnetite nanoparticles were separated by agarose gel electrophoresis and the hydrodynamic diameter distribution was determined in situ. For the different particle functionalizations and agarose concentrations tested, we could show that gel electrophoresis did not yield a complete separation of monomers and small aggregates, and that the electrophoretic mobility of the aggregates decreased linearly with the hydrodynamic diameter. Furthermore, the rotational particle diffusion was not clearly affected by nanoparticle-gel interactions. The possibility to detect nanoparticle aggregates and their hydrodynamic diameters in complex scattering media like cell tissue makes transient magnetic birefringence an interesting technique for biological applications.

  7. Radiation exposure in full-field digital mammography with a selenium flat-panel detector; Strahlenexposition bei der digitalen Vollfeldmammographie mit einem Selen-Flachdetektor

    Energy Technology Data Exchange (ETDEWEB)

    Gosch, D.; Jendrass, S.; Scholz, M.; Kahn, T. [Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Leipzig AoeR (Germany)

    2006-07-15

    Purpose: calculation of the average glandular dose for mammography on a full-field digital mammography system using a selenium flat-panel detector. Materials and methods: mammographic examinations were carried out using the selenia digital mammographic system from Lorad/Hologic. 1992 mammographies of 500 patients in cranio-caudal and medio-lateral projections were evaluated. Based on the recorded exposure conditions (tube voltage, tube loading, filtration, compressed breast thickness), the entrance surface air kerma was calculated by multiplying the tube loading by the measured tube output and was corrected according to the inverse square law. The average glandular dose was determined for each exposure by multiplying the entrance surface air kerma value by the relevant conversion factor for a breast composition of 50% adipose tissue and 50% glandular tissue by weight. Results: the mean values for patient age and compressed breast thickness were 61 years and 58 mm, respectively. The average glandular dose was 1.57 mGy for a single view (1.46 mGy for cranio-caudal view images and 1.68 mGy for medio-lateral view images). Conclusion: full-field digital mammography with a selenium flat-panel detector requires a dose similar to that of units with a flat-panel detector based on amorphous silicon and a dose approximately 20% lower than that of conventional screen/film mammography. (orig.)

  8. Waveform-based Bayesian full moment tensor inversion and uncertainty determination for the induced seismicity in an oil/gas field

    Science.gov (United States)

    Gu, Chen; Marzouk, Youssef M.; Toksöz, M. Nafi

    2018-03-01

    Small earthquakes occur due to natural tectonic motions and are induced by oil and gas production processes. In many oil/gas fields and hydrofracking processes, induced earthquakes result from fluid extraction or injection. The locations and source mechanisms of these earthquakes provide valuable information about the reservoirs. Analysis of induced seismic events has mostly assumed a double-couple source mechanism. However, recent studies have shown a non-negligible percentage of non-double-couple components of source moment tensors in hydraulic fracturing events, assuming a full moment tensor source mechanism. Without uncertainty quantification of the moment tensor solution, it is difficult to determine the reliability of these source models. This study develops a Bayesian method to perform waveform-based full moment tensor inversion and uncertainty quantification for induced seismic events, accounting for both location and velocity model uncertainties. We conduct tests with synthetic events to validate the method, and then apply our newly developed Bayesian inversion approach to real induced seismicity in an oil/gas field in the sultanate of Oman—determining the uncertainties in the source mechanism and in the location of that event.

  9. Non-contact full-field optical coherence tomography: a novel tool for in vivo imaging of the human cornea (Conference Presentation)

    Science.gov (United States)

    Mazlin, Viacheslav; Dalimier, Eugénie; Grieve, Katharine F.; Irsch, Kristina; Sahel, José-Alain; Fink, Mathias; Boccara, A. Claude

    2017-02-01

    According to the World Health Organization (WHO), corneal diseases alongside with cataract and retinal diseases are major causes of blindness worldwide. For the 95.5% of corneal blindness cases, prevention or rehabilitation could have been possible without negative consequences for vision, provided that disease is diagnosed early. However, diagnostics at the early stage requires cellular-level resolution, which is not achieved with routinely used Slit-lamp and OCT instruments. Confocal microscopy allows examination of the cornea at a resolution approaching histological detail, however requires contact with a patient's eye. The recently developed full-field OCT technique, in which 2D en face tangential optical slices are directly recorded on a camera, was successfully applied for ex vivo eye imaging. However, in vivo human eye imaging has not been demonstrated yet. Here we present a novel non-contact full-field OCT system, which is capable of imaging in air and, therefore, shows potential for in vivo cornea imaging in patients. The first cellular-level resolution ex vivo images of cornea, obtained in a completely non-contact way, were demonstrated. We were able to scan through the entire cornea (400 µm) and resolve epithelium, Bowman's layer, stroma and endothelium. FFOCT images of the human cornea in vivo were obtained for the first time. The epithelium structures and stromal keratocyte cells were distinguishable. Both ex vivo and in vivo images were acquired with a large (1.26 mm x 1.26 mm) field of view. Cellular details in obtained images make this device a promising candidate for realization of high-resolution in vivo cornea imaging.

  10. Non-linear polarization and chiral effects in birefringent solitons

    Indian Academy of Sciences (India)

    the Kerr effect, which is characterized by having a refraction index depending on the intensity of the applied field. An index of this type, for the case of optical fiber, means that there is a phase shift depending on the intensity and thus the temporal changes of phase are also temporal changes of frequency. Thus the Kerr-type ...

  11. 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.

  12. 3D nanoscale imaging of the yeast, Schizosaccharomyces pombe, by full-field transmission x-ray microscopy at 5.4 keV

    Science.gov (United States)

    Chen, Jie; Yang, Yunhao; Zhang, Xiaobo; Andrews, Joy C.; Pianetta, Piero; Guan, Yong; Liu, Gang; Xiong, Ying; Wu, Ziyu; Tian, Yangchao

    2010-01-01

    Three-dimensional (3D) nanoscale structures of the fission yeast, Schizosaccharomyces pombe, can be obtained by full-field transmission hard x-ray microscopy with 30 nm resolution using synchrotron radiation sources. Sample preparation is relatively simple and the samples are portable across various imaging environments, allowing for high throughput sample screening. The yeast cells were fixed and double stained with Reynold’s lead citrate and uranyl acetate. We performed both absorption contrast and Zernike phase contrast imaging on these cells in order to test this method. The membranes, nucleus and subcellular organelles of the cells were clearly visualized using absorption contrast mode. The x-ray images of the cells could be used to study the spatial distributions of the organelles in the cells. These results show unique structural information, demonstrating that hard x-ray microscopy is a complementary method for imaging and analyzing biological samples. PMID:20349228

  13. X-ray and visible light transmission as two-dimensional, full-field moisture-sensing techniques: A preliminary comparison

    International Nuclear Information System (INIS)

    Tidwell, V.C.; Glass, R.J.

    1992-01-01

    Two independent high-resolution moisture-sensing techniques, x-ray absorption and light transmission, have been developed for use in two-dimensional, thin-slab experimental systems. The techniques yield full-field measurement capabilities with exceptional resolution of moisture content in time and space. These techniques represent powerful tools for the experimentalist to investigate processes governing unsaturated flow and transport through fractured and nonfractured porous media. Evaluation of these techniques has been accomplished by direct comparison of data obtained by means of the x-ray and light techniques as well as comparison with data collected by gravimetric and gamma-ray densitometry techniques. Results show excellent agreement between data collected by the four moisture-content measurement techniques. This program was established to support the Yucca Mountain Site Characterization Project

  14. A new full-field digital mammography system with and without the use of an advanced post-processing algorithm: comparison of image quality and diagnostic performance.

    Science.gov (United States)

    Ahn, Hye Shin; Kim, Sun Mi; Jang, Mijung; Yun, Bo La; Kim, Bohyoung; Ko, Eun Sook; Han, Boo-Kyung; Chang, Jung Min; Yi, Ann; Cho, Nariya; Moon, Woo Kyung; Choi, Hye Young

    2014-01-01

    To compare new full-field digital mammography (FFDM) with and without use of an advanced post-processing algorithm to improve image quality, lesion detection, diagnostic performance, and priority rank. During a 22-month period, we prospectively enrolled 100 cases of specimen FFDM mammography (Brestige®), which was performed alone or in combination with a post-processing algorithm developed by the manufacturer: group A (SMA), specimen mammography without application of "Mammogram enhancement ver. 2.0"; group B (SMB), specimen mammography with application of "Mammogram enhancement ver. 2.0". Two sets of specimen mammographies were randomly reviewed by five experienced radiologists. Image quality, lesion detection, diagnostic performance, and priority rank with regard to image preference were evaluated. Three aspects of image quality (overall quality, contrast, and noise) of the SMB were significantly superior to those of SMA (p processing algorithm may improve image quality with better image preference in FFDM than without use of the software.

  15. Characterization of wet pad surface in chemical mechanical polishing (CMP) process with full-field optical coherence tomography (FF-OCT).

    Science.gov (United States)

    Choi, Woo June; Jung, Sung Pyo; Shin, Jun Geun; Yang, Danning; Lee, Byeong Ha

    2011-07-04

    Chemical mechanical polishing (CMP) is a key process for global planarization of silicon wafers for semiconductors and AlTiC wafers for magnetic heads. Removal rate of wafer material is directly dependent on the surface roughness of a CMP pad, thus the structure of the pad surface has been evaluated with variable techniques. However, under in situ CMP process, the measurements have been severely limited due to the existence of polishing fluids including the slurry on the pad surface. In here, we newly introduce ultra-high resolution full-field optical coherence tomography (FF-OCT) to investigate the surface of wet pads. With FF-OCT, the wet pad surface could be quantitatively characterized in terms of the polishing pad lifetime, and also be three-dimensionally visualized. We found that reasonable polishing span could be evaluated from the surface roughness measurement and the groove depth measurement made by FF-OCT.

  16. Deep learning in breast cancer risk assessment: evaluation of convolutional neural networks on a clinical dataset of full-field digital mammograms.

    Science.gov (United States)

    Li, Hui; Giger, Maryellen L; Huynh, Benjamin Q; Antropova, Natalia O

    2017-10-01

    To evaluate deep learning in the assessment of breast cancer risk in which convolutional neural networks (CNNs) with transfer learning are used to extract parenchymal characteristics directly from full-field digital mammographic (FFDM) images instead of using computerized radiographic texture analysis (RTA), 456 clinical FFDM cases were included: a "high-risk" BRCA1/2 gene-mutation carriers dataset (53 cases), a "high-risk" unilateral cancer patients dataset (75 cases), and a "low-risk dataset" (328 cases). Deep learning was compared to the use of features from RTA, as well as to a combination of both in the task of distinguishing between high- and low-risk subjects. Similar classification performances were obtained using CNN [area under the curve [Formula: see text]; standard error [Formula: see text

  17. Effective mass approximation versus full atomistic model to calculate the output characteristics of a gate-all-around germanium nanowire field effect transistor (GAA-GeNW-FET)

    Science.gov (United States)

    Bayani, Amir Hossein; Voves, Jan; Dideban, Daryoosh

    2018-01-01

    Here, we compare the output characteristics of a gate-all-around germanium nanowire field effect transistor (GAA-GeNW-FET) with 2.36 nm2 square cross-section area using tight-binding (TB) sp3d5s∗ model (full atomistic model (FAM)) and effective mass approximation (EMA). Synopsys/QuantumWise Atomistix ToolKit (ATK) and Silvaco Atlas3D are used to consider the TB model and EMA, respectively. Results show that EMA predicted only one quantum state (QS) for quantum transport, whereas FAM predicted three QSs. A cosine function behavior is obtained by both methods for the first quantum state. The calculated bandgap value by EMA is almost twice smaller than that of the FAM. Also, a fluctuating current is predicted by both methods but in different oscillation values.

  18. Method for the unique identification of hyperelastic material properties using full-field measures. Application to the passive myocardium material response.

    Science.gov (United States)

    Perotti, Luigi E; Ponnaluri, Aditya V S; Krishnamoorthi, Shankarjee; Balzani, Daniel; Ennis, Daniel B; Klug, William S

    2017-11-01

    Quantitative measurement of the material properties (eg, stiffness) of biological tissues is poised to become a powerful diagnostic tool. There are currently several methods in the literature to estimating material stiffness, and we extend this work by formulating a framework that leads to uniquely identified material properties. We design an approach to work with full-field displacement data-ie, we assume the displacement field due to the applied forces is known both on the boundaries and also within the interior of the body of interest-and seek stiffness parameters that lead to balanced internal and external forces in a model. For in vivo applications, the displacement data can be acquired clinically using magnetic resonance imaging while the forces may be computed from pressure measurements, eg, through catheterization. We outline a set of conditions under which the least-square force error objective function is convex, yielding uniquely identified material properties. An important component of our framework is a new numerical strategy to formulate polyconvex material energy laws that are linear in the material properties and provide one optimal description of the available experimental data. An outcome of our approach is the analysis of the reliability of the identified material properties, even for material laws that do not admit unique property identification. Lastly, we evaluate our approach using passive myocardium experimental data at the material point and show its application to identifying myocardial stiffness with an in silico experiment modeling the passive filling of the left ventricle. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Screening mammography-detected cancers: the sensitivity of the computer-aided detection system as applied to full-field digital mammography

    International Nuclear Information System (INIS)

    Yang, Sang Kyu; Cho, Nariya; Ko, Eun Sook; Kim, Do Yeon; Moon, Woo Kyung

    2006-01-01

    We wanted to evaluate the sensitivity of the computer-aided detection (CAD) system for performing full-field digital mammography (FFDM) on the breast cancers that were originally detected by screening mammography. The CAD system (Image Checker v3.1, R2 Technology, Los Altos, Calif.) together with a full-field digital mammography system (Senographe 2000D, GE Medical Systems, Buc, France) was prospectively applied to the mammograms of 70 mammographically detected breast cancer patients (age range, 37-69; median age, 51 years) who had negative findings on their clinical examinations. The sensitivity of the CAD system, according to histopathologic findings and radiologic primary features (i.e, mass, microcalcifications or mass with microcalcifications) and also the false-positive marking rate were then determined. The CAD system correctly depicted 67 of 70 breast cancer lesions (97.5%). The CAD system marked 29 of 30 breast cancers that presented with microcalcifications only (sensitivity 96.7%) and all 18 breast cancers the presented with mass together with microcalcifications (sensitivity 100%). Twenty of the 22 lesions that appeared as a mass only were marked correctly by the CAD system (sensitivity 90.9%). The CAD system correctly depicted all 22 lesions of ductal carcinoma in situ (sensitivity: 100%), all 13 lesions of invasive ductal carcinoma with ductal carcinoma in situ (sensitivity: 100%) and the 1 lesion of invasive lobular carcinoma (sensitivity: 100%). Thirty one of the 34 lesions of invasive ductal carcinoma were marked correctly by the CAD system (sensitivity: 91.8%). The rate of false-positive marks was 0.21 mass marks per image and 0.16 microcalcification marks per image. The overall rate of false-positive marks was 0.37 per image. The CAD system using FFDM is useful for the detection of asymptomatic breast cancers, and it has a high overall tumor detection rate. The false negative cases were found in relatively small invasive ductal carcinoma

  20. Screening mammography-detected cancers: the sensitivity of the computer-aided detection system as applied to full-field digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Sang Kyu; Cho, Nariya; Ko, Eun Sook; Kim, Do Yeon; Moon, Woo Kyung [College of Medicine Seoul National University and The Insititute of Radiation Medicine, Seoul National University Research Center, Seoul (Korea, Republic of)

    2006-04-15

    We wanted to evaluate the sensitivity of the computer-aided detection (CAD) system for performing full-field digital mammography (FFDM) on the breast cancers that were originally detected by screening mammography. The CAD system (Image Checker v3.1, R2 Technology, Los Altos, Calif.) together with a full-field digital mammography system (Senographe 2000D, GE Medical Systems, Buc, France) was prospectively applied to the mammograms of 70 mammographically detected breast cancer patients (age range, 37-69; median age, 51 years) who had negative findings on their clinical examinations. The sensitivity of the CAD system, according to histopathologic findings and radiologic primary features (i.e, mass, microcalcifications or mass with microcalcifications) and also the false-positive marking rate were then determined. The CAD system correctly depicted 67 of 70 breast cancer lesions (97.5%). The CAD system marked 29 of 30 breast cancers that presented with microcalcifications only (sensitivity 96.7%) and all 18 breast cancers the presented with mass together with microcalcifications (sensitivity 100%). Twenty of the 22 lesions that appeared as a mass only were marked correctly by the CAD system (sensitivity 90.9%). The CAD system correctly depicted all 22 lesions of ductal carcinoma in situ (sensitivity: 100%), all 13 lesions of invasive ductal carcinoma with ductal carcinoma in situ (sensitivity: 100%) and the 1 lesion of invasive lobular carcinoma (sensitivity: 100%). Thirty one of the 34 lesions of invasive ductal carcinoma were marked correctly by the CAD system (sensitivity: 91.8%). The rate of false-positive marks was 0.21 mass marks per image and 0.16 microcalcification marks per image. The overall rate of false-positive marks was 0.37 per image. The CAD system using FFDM is useful for the detection of asymptomatic breast cancers, and it has a high overall tumor detection rate. The false negative cases were found in relatively small invasive ductal carcinoma.

  1. A full-field residual stress estimation scheme for fitness-for-service assessment of pipe girth welds: Part II – A shell theory based implementation

    International Nuclear Information System (INIS)

    Song, Shaopin; Dong, Pingsha; Pei, Xianjun

    2015-01-01

    With the two key controlling parameters identified and their effectiveness demonstrated in Part I of this study series for constructing a continuous residual stress profile at weld region, a classical shell theory based model is proposed in this paper (Part II) for describing through-thickness residual stress distributions of both axial and hoop components at any axial location beyond weld region. The shell theory based model is analytically constructed through an assembly of two parts: One represents weld region and the other represents the remaining component section away from weld. The final assembly of the two parts leads to a closed form solution to both axial and hoop residual stress components as a function of axial distance from weld toe position. The effectiveness of the full-field residual stress estimation scheme is demonstrated by comparing with a series of finite element modeling results over a broad range of pipe weld geometries and welding conditions. The present development should provide a consistent and effective means for estimating through-thickness residual stress profile as a continuous function of pipe geometry, welding heat input, as well as material characteristics. - Highlights: • A shell theory based two-part assembly model is developed for generalizing residual stress distributions. • A full-field estimation of through-thickness residual stress profiles can be achieved. • The proposed estimation scheme offers both consistency and mechanics basis in residual stress profile generation. • An estimation scheme for welding-induced plastic zone size is proposed and validated. • The shell theory based estimation scheme can also provide a reasonable estimate on distortion in radial direction

  2. Full vector archaeomagnetic records from Anatolia between 2400 and 1350 BCE: Implications for geomagnetic field models and the dating of fires in antiquity

    Science.gov (United States)

    Ertepinar, P.; Langereis, C. G.; Biggin, A. J.; de Groot, L. V.; Kulakoğlu, F.; Omura, S.; Süel, A.

    2016-01-01

    Anatolia, as one of the busiest crossroads of ancient civilizations, provides an ideal platform for archaeomagnetic studies. Previous results from the Middle East have suggested the occurrence of a strong peak in geomagnetic intensity at ∼1000 BCE associated with dramatic field strength variations that could require a radical rethinking of geodynamo theory. The behavior of the field in the centuries preceding this peak remains poorly constrained, however. Here we present the results of full-vector archaeomagnetic experiments performed on 18 sets of samples from three archaeological sites belonging to Assyrian Trade Colony and Hittite periods. Associated rock magnetic analyses showed that the major magnetic carrier is magnetite chemically stable up to 700 °C and the magnetic mineral assemblage is composed mostly of non-interacting PSD grains. The directional results are compared with existing data and with the most recent global geomagnetic field models pfm9k.1b and SHA.DIF.14k. The directions are in remarkably good agreement with SHA.DIF.14k which is based on archaeomagnetic and lava flow data. Together with our earlier results from Anatolia, we triple the existing database of directions for the 700 year long period 2200-1500 BCE, over a large region from Greece to Azerbaijan, and from Moldavia/Ukraine to Egypt. Three archaeointensity methods: thermal IZZI-Thellier, microwave Thellier and the multi-specimen protocol (MSP) produced virtual axial dipole moment estimates (9.0- 10.9 ×1022 Am2) that are somewhat higher than contemporaneous (regional and global) data and model predictions suggesting that the field was already substantially stronger than today more than 800 years prior to the reported peak. In addition to constraining geomagnetic variability, our data also allow us to assign relative dates to inferred fire events in the Assyrian Trade Colony Period sites. This allows us to conclude that the fire events at the largest site, Kültepe, were not all

  3. Comparing the diagnostic efficacy of full field digital mammography with digital breast tomosynthesis using BIRADS score in a tertiary cancer care hospital

    Directory of Open Access Journals (Sweden)

    Divya Singla

    2018-01-01

    Full Text Available Introduction: Breast cancer is one of the leading cancers in females worldwide, and its incidence has been rising at an exponential pace in the last 10 years even in India. Mammography has been the mainstay for detection of breast cancer over decades and has gradually advanced from screen film to full-field digital mammography. Recently, tomosynthesis has evolved as an advanced imaging investigation for early diagnosis of breast lesions in both diagnostic and screening settings. Aim of Study: To compare and evaluate the impact of digital breast tomosynthesis (DBT compared to full-field digital mammography (FFDM in the interpretation of BIRADS score in both diagnostic and screening settings. Settings and Design: A 1-year prospective longitudinal study was conducted in the Department of Radio-diagnosis in our institute using Hologic Selenia Dimensions for mammography as well as tomosynthesis. Materials and Methods: One hundred women known or suspected (opportunistic screening for breast cancer were evaluated either with FFDM alone or both FFDM and DBT. Sensitivity, specificity, positive predictive value, negative predictive value, and P value were used to assess the various diagnostic criteria in our study. Results: Addition of DBT to FFDM results in a statistically significant increase in the sensitivity, specificity, and positive predictive value, and a statistically significant decrease in the false positive rates. Similar results were noted in both diagnostic and screening cases. It was observed that, in most cases, i.e. a total of 47, DBT did not change the BIRADS scoring; however, its addition increased the diagnostic confidence. BIRADS was upgraded and downgraded in 14 and 31 cases, respectively, with the addition of DBT to FFDM. New lesions were seen with addition of DBT to FFDM in 8 cases. Conclusion: Addition of DBT to FFDM results in increase in sensitivity, specificity, positive predictive value, and a statistically significant

  4. 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.

  5. 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.

  6. 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.

  7. Exploiting cellophane birefringence to generate radially and azimuthally polarised vector beams

    International Nuclear Information System (INIS)

    Kalwe, Johnston; Ominde, Calvine; Rurimo, Geoffrey; Neugebauer, Martin; Leuchs, Gerd; Banzer, Peter

    2015-01-01

    We exploit the birefringence of cellophane to convert a linearly polarised Gaussian beam into either a radially or azimuthally polarised beam. For that, we fabricated a low-cost polarisation mask consisting of four segments of cellophane. The fast axis of each segment is oriented appropriately in order to rotate the polarisation of the incident linearly polarised beam as desired. To ensure the correct operation of the polarisation mask, we tested the polarisation state of the generated beam by measuring the spatial distribution of the Stokes parameters. Such a device is very cost efficient and allows for the generation of cylindrical vector beams of high quality. (paper)

  8. Computer-aided detection system for clustered microcalcifications: comparison of performance on full-field digital mammograms and digitized screen-film mammograms

    International Nuclear Information System (INIS)

    Ge Jun; Hadjiiski, Lubomir M; Sahiner, Berkman; Wei Jun; Helvie, Mark A; Zhou Chuan; Chan Heangping

    2007-01-01

    We have developed a computer-aided detection (CAD) system to detect clustered microcalcifications automatically on full-field digital mammograms (FFDMs) and a CAD system for screen-film mammograms (SFMs). The two systems used the same computer vision algorithms but their false positive (FP) classifiers were trained separately with sample images of each modality. In this study, we compared the performance of the CAD systems for detection of clustered microcalcifications on pairs of FFDM and SFM obtained from the same patient. For case-based performance evaluation, the FFDM CAD system achieved detection sensitivities of 70%, 80% and 90% at an average FP cluster rate of 0.07, 0.16 and 0.63 per image, compared with an average FP cluster rate of 0.15, 0.38 and 2.02 per image for the SFM CAD system. The difference was statistically significant with the alternative free-response receiver operating characteristic (AFROC) analysis. When evaluated on data sets negative for microcalcification clusters, the average FP cluster rates of the FFDM CAD system were 0.04, 0.11 and 0.33 per image at detection sensitivity level of 70%, 80% and 90% compared with an average FP cluster rate of 0.08, 0.14 and 0.50 per image for the SFM CAD system. When evaluated for malignant cases only, the difference of the performance of the two CAD systems was not statistically significant with AFROC analysis

  9. A Survey On Mean Glandular Dose From Full-Field Digital Mammography Systems, Operate Using Mo/ Mo And W/Rh Target/ Filter Combinations

    International Nuclear Information System (INIS)

    Noriah Jamal; Siti Selina Abdul Hamid; Humairah Samad Cheung; Siti Kamariah Che Mohamed; Ellyda Muhammed Nordin; Radhiana Hassan; Rehir Dahalan

    2013-01-01

    We had conducted a survey on Mean Glandular Dose (MGD) from Full-Field Digital Mammography systems (FFDM) operate using Molybdenum/ Molybdenum (Mo/ Mo) and Tungsten/ Rhodium (W/ Rh) target/ filter combinations. A survey was carried out at two randomly selected mammography centres in Malaysia, namely National Cancer Society and International Islamic University of Malaysia. The first centre operates using a W/ Rh, while the second centre operates using an Mo/ Mo target/ filter combinations. On the basis of recorded information, data on mammographic views, MGD, age and Compressed Breast Thickness (CBT) were recorded for 100 patients, for each mammographic centre respectively. The MGD data were analyzed for variation with age group, with 5 years increment. The MGD data were also analyzed for variation with CBT, with 5 mm increment. We found that for both CC and MLO views, FFDM systems operated using Mo/ Mo and W/ Rh target/ filter combinations present the same trend on MGD. The average MGD decreases as age increases. While average MGD increases with the increasing of CBT. However, FFDM system operates using Mo/ Mo gives higher MGD as compared with FFDM system operates using W/ Rh. (author)

  10. Revealing the cellular metabolism and microstructural changes in vivo in senescing Acer saccharum leaves using two-photon FLIM and full-field OCM

    Science.gov (United States)

    Chakraborty, Sandeep; Anna, Tulsi; Kuo, Wen-Chuan; Chiou, Arthur

    2016-10-01

    Seasonal as well as climate changes have immense effect on bud burst, leaf color and leaf abscission. Autumn phenology of leaves is clearly distinguishable in deciduous plant leaves where the leaf color changes from green to red (leaf senescence). In this work, two-photon fluorescence lifetime imaging microscopy (2P-FLIM) and full-field optical coherence microscopy (FF-OCM) were applied to study mitochondrial activity and microstructural changes, respectively, in the senescence of Acer saccharum (Sugar maple) leaves. Fluorescence lifetime of reduced nicotinamide adenine dinucleotide phosphate [NAD(P)H] was recorded using 2P-FLIM to quantify the cellular metabolic changes. Compared to the green leaves, the red leaves showed a 19% increase (P fluorescence lifetime of NAD(P)H, and a 52% decrease (p protein-bound NAD(P)H ratio. This infers a significant change in mitochondrial metabolic regulation in red leaves in contrast to green leaves. Additionally, en-face sectional images at 0.8 μm axial resolutions of the green and the red color Acer saccharum leaves via FF-OCM using white light emitting diode (WLED) showed a well-defined microstructure of epicuticular waxy layer in green leaves as compared to red leaves where disintegrated microstructure was observed. Our approach can potentially be used to correlate mitochondrial activity with epicuticular microstructural changes in senescing leaves and other biological tissues.

  11. A new full-field digital mammography system with and without the use of an advanced post-processing algorithm: Comparison of image quality and diagnostic performance

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Hye Shin; Kim, Sun Mi; Jang, Mi Jung; Yun, Bo La; Kim, Boh Young [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Ko, Eun Sook; Han, Boo Kyung [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Chang, Jung Min; Yi, Ann; Cho, Nariya; Moon, Woo Kyung [Dept. of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of); Choi, Hye Young [Dept. of Radiology, Gyeongsang National University Hospital, Jinju (Korea, Republic of)

    2014-06-15

    To compare new full-field digital mammography (FFDM) with and without use of an advanced post-processing algorithm to improve image quality, lesion detection, diagnostic performance, and priority rank. During a 22-month period, we prospectively enrolled 100 cases of specimen FFDM mammography (Brestige), which was performed alone or in combination with a post-processing algorithm developed by the manufacturer: group A (SMA), specimen mammography without application of {sup M}ammogram enhancement ver. 2.0{sup ;} group B (SMB), specimen mammography with application of {sup M}ammogram enhancement ver. 2.0{sup .} Two sets of specimen mammographies were randomly reviewed by five experienced radiologists. Image quality, lesion detection, diagnostic performance, and priority rank with regard to image preference were evaluated. Three aspects of image quality (overall quality, contrast, and noise) of the SMB were significantly superior to those of SMA (p < 0.05). SMB was significantly superior to SMA for visualizing calcifications (p < 0.05). Diagnostic performance, as evaluated by cancer score, was similar between SMA and SMB. SMB was preferred to SMA by four of the five reviewers. The post-processing algorithm may improve image quality with better image preference in FFDM than without use of the software.

  12. 3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map

    Science.gov (United States)

    Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Franzen, P.; Fantz, U.; Minea, T.

    2014-02-01

    Decreasing the co-extracted electron current while simultaneously keeping negative ion (NI) current sufficiently high is a crucial issue on the development plasma source system for ITER Neutral Beam Injector. To support finding the best extraction conditions the 3D Particle-in-Cell Monte Carlo Collision electrostatic code ONIX (Orsay Negative Ion eXtraction) has been developed. Close collaboration with experiments and other numerical models allows performing realistic simulations with relevant input parameters: plasma properties, geometry of the extraction aperture, full 3D magnetic field map, etc. For the first time ONIX has been benchmarked with commercial positive ions tracing code KOBRA3D. A very good agreement in terms of the meniscus position and depth has been found. Simulation of NI extraction with different e/NI ratio in bulk plasma shows high relevance of the direct negative ion extraction from the surface produced NI in order to obtain extracted NI current as in the experimental results from BATMAN testbed.

  13. Non-destructive analysis of flake properties in automotive paints with full-field optical coherence tomography and 3D segmentation.

    Science.gov (United States)

    Zhang, Jinke; Williams, Bryan M; Lawman, Samuel; Atkinson, David; Zhang, Zijian; Shen, Yaochun; Zheng, Yalin

    2017-08-07

    Automotive coating systems are designed to protect vehicle bodies from corrosion and enhance their aesthetic value. The number, size and orientation of small metallic flakes in the base coat of the paint has a significant effect on the appearance of automotive bodies. It is important for quality assurance (QA) to be able to measure the properties of these small flakes, which are approximately 10μm in radius, yet current QA techniques are limited to measuring layer thickness. We design and develop a time-domain (TD) full-field (FF) optical coherence tomography (OCT) system to scan automotive panels volumetrically, non-destructively and without contact. We develop and integrate a segmentation method to automatically distinguish flakes and allow measurement of their properties. We test our integrated system on nine sections of five panels and demonstrate that this integrated approach can characterise small flakes in automotive coating systems in 3D, calculating the number, size and orientation accurately and consistently. This has the potential to significantly impact QA testing in the automotive industry.

  14. Comparison of full field and anomaly initialisation for decadal climate prediction: towards an optimal consistency between the ocean and sea-ice anomaly initialisation state

    Science.gov (United States)

    Volpi, Danila; Guemas, Virginie; Doblas-Reyes, Francisco J.

    2017-08-01

    Decadal prediction exploits sources of predictability from both the internal variability through the initialisation of the climate model from observational estimates, and the external radiative forcings. When a model is initialised with the observed state at the initial time step (Full Field Initialisation—FFI), the forecast run drifts towards the biased model climate. Distinguishing between the climate signal to be predicted and the model drift is a challenging task, because the application of a-posteriori bias correction has the risk of removing part of the variability signal. The anomaly initialisation (AI) technique aims at addressing the drift issue by answering the following question: if the model is allowed to start close to its own attractor (i.e. its biased world), but the phase of the simulated variability is constrained toward the contemporaneous observed one at the initialisation time, does the prediction skill improve? The relative merits of the FFI and AI techniques applied respectively to the ocean component and the ocean and sea ice components simultaneously in the EC-Earth global coupled model are assessed. For both strategies the initialised hindcasts show better skill than historical simulations for the ocean heat content and AMOC along the first two forecast years, for sea ice and PDO along the first forecast year, while for AMO the improvements are statistically significant for the first two forecast years. The AI in the ocean and sea ice components significantly improves the skill of the Arctic sea surface temperature over the FFI.

  15. Label-free characterization of vitrification-induced morphology changes in single-cell embryos with full-field optical coherence tomography

    Science.gov (United States)

    Zarnescu, Livia; Leung, Michael C.; Abeyta, Michael; Sudkamp, Helge; Baer, Thomas; Behr, Barry; Ellerbee, Audrey K.

    2015-09-01

    Vitrification is an increasingly popular method of embryo cryopreservation that is used in assisted reproductive technology. Although vitrification has high post-thaw survival rates compared to other freezing techniques, its long-term effects on embryo development are still poorly understood. We demonstrate an application of full-field optical coherence tomography (FF-OCT) to visualize the effects of vitrification on live single-cell (2 pronuclear) mouse embryos without harmful labels. Using FF-OCT, we observed that vitrification causes a significant increase in the aggregation of structures within the embryo cytoplasm, consistent with reports in literature based on fluorescence techniques. We quantify the degree of aggregation with an objective metric, the cytoplasmic aggregation (CA) score, and observe a high degree of correlation between the CA scores of FF-OCT images of embryos and of fluorescence images of their mitochondria. Our results indicate that FF-OCT shows promise as a label-free assessment of the effects of vitrification on embryo mitochondria distribution. The CA score provides a quantitative metric to describe the degree to which embryos have been affected by vitrification and could aid clinicians in selecting embryos for transfer.

  16. Analysis of the Unsteady Flow Field in a Centrifugal Compressor from Peak Efficiency to Near Stall with Full-Annulus Simulations

    Directory of Open Access Journals (Sweden)

    Yannick Bousquet

    2014-01-01

    Full Text Available This study concerns a 2.5 pressure ratio centrifugal compressor stage consisting of a splittered unshrouded impeller and a vaned diffuser. The aim of this paper is to investigate the modifications of the flow structure when the operating point moves from peak efficiency to near stall. The investigations are based on the results of unsteady three-dimensional simulations, in a calculation domain comprising all the blade. A detailed analysis is given in the impeller inducer and in the vaned diffuser entry region through time-averaged and unsteady flow field. In the impeller inducer, this study demonstrates that the mass flow reduction from peak efficiency to near stall leads to intensification of the secondary flow effects. The low momentum fluid accumulated near the shroud interacts with the main flow through a shear layer zone. At near stall condition, the interface between the two flow structures becomes unstable leading to vortices development. In the diffuser entry region, by reducing the mass flow, the high incidence angle from the impeller exit induces a separation on the diffuser vane suction side. At near stall operating point, vorticity from the separation is shed into vortex cores which are periodically formed and convected downstream along the suction side.

  17. 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.

  18. High birefringence and near-zero dispersion photonic crystal fiber at the wavelength of 1.55μm

    Science.gov (United States)

    Song, Peng; Wu, Limin; Wang, Jing; Zhou, Cheng

    2016-03-01

    We investigate a photonic crystal fiber (PCF) which consists of squeezed triangle lattice and elliptical air holes. Birefringence and dispersion properties of this PCF have been numerically estimated by the supercell lattice method. Numerical results show that the birefringence is on the order of 10-2 over ultrabroad wavelength rang from1.3μm to 1.7μm and birefringence can be reached 1.71×10-2 at the operating wavelength of 1.55μm. It is also demonstrated that two near-zero dispersion of -1.75(ps/nm/km) (x-polarized mode) and-0.33(ps/nm/km) (y-polarized mode) at 1.55μm can be achieved. Morever, the fluctuations of the dispersion with fiber parameters are very small. The simulation results show that our proposed PCF are robust to fabrication imperfections.

  19. 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.

  20. 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.

  1. Multi-scale full-field measurements and near-wall modeling of turbulent subcooled boiling flow using innovative experimental techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Yassin A., E-mail: y-hassan@tamu.edu

    2016-04-01

    Highlights: • Near wall full-field velocity components under subcooled boiling were measured. • Simultaneous shadowgraphy, infrared thermometry wall temperature and particle-tracking velocimetry techniques were combined. • Near wall velocity modifications under subcooling boiling were observed. - Abstract: Multi-phase flows are one of the challenges on which the CFD simulation community has been working extensively with a relatively low success. The phenomena associated behind the momentum and heat transfer mechanisms associated to multi-phase flows are highly complex requiring resolving simultaneously for multiple scales on time and space. Part of the reasons behind the low predictive capability of CFD when studying multi-phase flows, is the scarcity of CFD-grade experimental data for validation. The complexity of the phenomena and its sensitivity to small sources of perturbations makes its measurements a difficult task. Non-intrusive and innovative measuring techniques are required to accurately measure multi-phase flow parameters while at the same time satisfying the high resolution required to validate CFD simulations. In this context, this work explores the feasible implementation of innovative measuring techniques that can provide whole-field and multi-scale measurements of two-phase flow turbulence, heat transfer, and boiling parameters. To this end, three visualization techniques are simultaneously implemented to study subcooled boiling flow through a vertical rectangular channel with a single heated wall. These techniques are listed next and are used as follow: (1) High-speed infrared thermometry (IR-T) is used to study the impact of the boiling level on the heat transfer coefficients at the heated wall, (2) Particle Tracking Velocimetry (PTV) is used to analyze the influence that boiling parameters have on the liquid phase turbulence statistics, (3) High-speed shadowgraphy with LED illumination is used to obtain the gas phase dynamics. To account

  2. 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.

  3. 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.

  4. Multiparameter full waveform inversion of multicomponent ocean-bottom-cable data from the Valhall field. Part 1: imaging compressional wave speed, density and attenuation

    Science.gov (United States)

    Prieux, Vincent; Brossier, Romain; Operto, Stéphane; Virieux, Jean

    2013-09-01

    Multiparameter full waveform inversion (FWI) is a challenging quantitative seismic imaging method for lithological characterization and reservoir monitoring. The difficulties in multiparameter FWI arise from the variable influence of the different parameter classes on the phase and amplitude of the data, and the trade-off between these. In this framework, choosing a suitable parametrization of the subsurface and designing the suitable FWI workflow are two key methodological issues in non-linear waveform inversion. We assess frequency-domain visco-acoustic FWI to reconstruct the compressive velocity (VP), the density (ρ) or the impedance (IP) and the quality factor (QP), from the hydrophone component, using a synthetic data set that is representative of the Valhall oil field in the North Sea. We first assess which of the (VP, ρ) and (VP, IP) parametrizations provides the most reliable FWI results when dealing with wide-aperture data. Contrary to widely accepted ideas, we show that the (VP, ρ) parametrization allows a better reconstruction of both the VP, ρ and IP parameters, first because it favours the broad-band reconstruction of the dominant VP parameter, and secondly because the trade-off effects between velocity and density at short-to-intermediate scattering angles can be removed by multiplication, to build an impedance model. This allows for the matching of the reflection amplitudes, while the broad-band velocity model accurately describes the kinematic attributes of both the diving waves and reflections. Then, we assess different inversion strategies to recover the quality factor QP, in addition to parameters VP and ρ. A difficulty related to attenuation estimation arises because, on the one hand the values of QP are on average one order of magnitude smaller than those of VP and ρ, and on the other hands model perturbations relative to the starting models can be much higher for QP than for VP and ρ during FWI. In this framework, we show that an

  5. 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.

  6. New, simple theory-based, accurate polarization microscope for birefringence imaging of biological cells

    Science.gov (United States)

    Shin, In Hee; Shin, Sang-Mo; Kim, Dug Young

    2010-01-01

    We propose a new, simple theory-based, accurate polarization microscope for birefringence imaging of cytoskeletal structures of biological cells. The new theory lets us calculate very easily the phase retardation and the orientation of the principal axis of a particular area of a biological living cell in media by simply measuring the intensity variation of a pixel of a CCD camera while rotating a single polarizer. Just from the measured intensity maxima and minima, the amount of phase retardation δ between the fast and the slow axis of the sample area is obtained with an accuracy of 5.010+/-0.798×10-3 rad. The orientation of the principal axis is calculated from the angle of the polarizer for the intensity maximum. We have compared our microscopes with two previously reported polarization microscopes for birefringence imaging of cytoskeletal structures and demonstrated the utility of our microscope with the phase retardation and orientation images of weakly invasive MCF7 and highly invasive MDA MB 231 human breast cancer cells as an example.

  7. 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.

  8. In situ remediation of chlorinated solvent-contaminated groundwater using ZVI/organic carbon amendment in China: field pilot test and full-scale application.

    Science.gov (United States)

    Yang, Jie; Meng, Liang; Guo, Lin

    2018-02-01

    Chlorinated solvents in groundwater pose threats to human health and the environment due to their carcinogenesis and bioaccumulation. These problems are often more severe in developing countries such as China. Thus, methods for chlorinated solvent-contaminated groundwater remediation are urgently needed. This study presents a technique of in situ remediation via the direct-push amendment injection that enhances the reductive dechlorination of chlorinated solvents in groundwater in the low-permeability aquifer. A field-based pilot test and a following real-world, full-scale application were conducted at an active manufacturing facility in Shanghai, China. The chlorinated solvents found at the clay till site included 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethane (1,1-DCA), 1,1-dichloroethylene (1,1-DCE), vinyl chloride (VC), and chloroethane (CA). A commercially available amendment (EHC ® , Peroxychem, Philadelphia, PA) combining zero-valent iron and organic carbon was used to treat the above pollutants. Pilot test results showed that direct-push EHC injection efficiently facilitated the in situ reductive remediation of groundwater contaminated with chlorinated solvents. The mean removal rates of 1,1,1-TCA, 1,1-DCA, and 1,1-DCE at 270 days post-injection were 99.6, 99.3, and 73.3%, respectively, which were obviously higher than those of VC and CA (42.3 and 37.1%, respectively). Clear decreases in oxidation-reduction potential and dissolved oxygen concentration, and increases in Fe 2+ and total organic carbon concentration, were also observed during the monitoring period. These indicate that EHC promotes the anaerobic degradation of chlorinated hydrocarbons primarily via long-term biological reductive dechlorination, with instant chemical reductive dechlorination acting as a secondary pathway. The optimal effective time of EHC injection was 0-90 days, and its radius of influence was 1.5 m. In full-scale application, the maximum concentrations of 1,1,1-TCA

  9. X-ray induced formation of γ-H2AX foci after full-field digital mammography and digital breast-tomosynthesis.

    Directory of Open Access Journals (Sweden)

    Siegfried A Schwab

    Full Text Available PURPOSE: To determine in-vivo formation of x-ray induced γ-H2AX foci in systemic blood lymphocytes of patients undergoing full-field digital mammography (FFDM and to estimate foci after FFDM and digital breast-tomosynthesis (DBT using a biological phantom model. MATERIALS AND METHODS: The study complies with the Declaration of Helsinki and was performed following approval by the ethic committee of the University of Erlangen-Nuremberg. Written informed consent was obtained from every patient. For in-vivo tests, systemic blood lymphocytes were obtained from 20 patients before and after FFDM. In order to compare in-vivo post-exposure with pre-exposure foci levels, the Wilcoxon matched pairs test was used. For in-vitro experiments, isolated blood lymphocytes from healthy volunteers were irradiated at skin and glandular level of a porcine breast using FFDM and DBT. Cells were stained against the phosphorylated histone variant γ-H2AX, and foci representing distinct DNA damages were quantified. RESULTS: Median in-vivo foci level/cell was 0.086 (range 0.067-0.116 before and 0.094 (0.076-0.126 after FFDM (p = 0.0004. In the in-vitro model, the median x-ray induced foci level/cell after FFDM was 0.120 (range 0.086-0.140 at skin level and 0.035 (range 0.030-0.050 at glandular level. After DBT, the median x-ray induced foci level/cell was 0.061 (range 0.040-0.081 at skin level and 0.015 (range 0.006-0.020 at glandular level. CONCLUSION: In patients, mammography induces a slight but significant increase of γ-H2AX foci in systemic blood lymphocytes. The introduced biological phantom model is suitable for the estimation of x-ray induced DNA damages in breast tissue in different breast imaging techniques.

  10. Multiparameter full waveform inversion of multicomponent ocean-bottom-cable data from the Valhall field. Part 2: imaging compressive-wave and shear-wave velocities

    Science.gov (United States)

    Prieux, Vincent; Brossier, Romain; Operto, Stéphane; Virieux, Jean

    2013-09-01

    Multiparameter elastic full waveform inversion (FWI) is a promising technology that allows inferences to be made on rock and fluid properties, which thus narrows the gap between seismic imaging and reservoir characterization. Here, we assess the feasibility of 2-D vertical transverse isotropic visco-elastic FWI of wide-aperture multicomponent ocean-bottom-cable data from the Valhall oil field. A key issue is to design a suitable hierarchical data-driven and model-driven FWI workflow, the aim of which is to reduce the nonlinearity of the FWI. This nonlinearity partly arises because the shear (S) wavespeed can have a limited influence on seismic data in marine environments. In a preliminary stage, visco-acoustic FWI of the hydrophone component is performed to build a compressional (P)-wave velocity model, a density model and a quality-factor model, which provide the necessary background models for the subsequent elastic inversion. During the elastic FWI, the P and S wavespeeds are jointly updated in two steps. First, the hydrophone data are inverted to mainly update the long-to-intermediate wavelengths of the S wavespeeds from the amplitude-versus-offset variations of the P-P reflections. This S-wave velocity model is used as an improved starting model for the subsequent inversion of the better-resolving data recorded by the geophones. During these two steps, the P-wave velocity model is marginally updated, which supports the relevance of the visco-acoustic FWI results. Through seismic modelling, we show that the resulting visco-elastic model allows several P-to-S converted phases recorded on the horizontal-geophone component to be matched. Several elastic quantities, such as the Poisson ratio, and the ratio and product between the P and S wavespeeds, are inferred from the P-wave and S-wave velocity models. These attributes provide hints for the interpretation of an accumulation of gas below lithological barriers.

  11. Diagnostic performance of digital breast tomosynthesis with a wide scan angle compared to full-field digital mammography for the detection and characterization of microcalcifications

    Energy Technology Data Exchange (ETDEWEB)

    Clauser, Paola, E-mail: paola.clauser@meduniwien.ac.at [Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Nagl, Georg [Department for Radiology and Interventional Radiology, Landesklinikum Horn, Spitalgasse 10, 3580 Horn (Austria); Helbich, Thomas H., E-mail: thomas.helbich@meduniwien.ac.at [Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Pinker-Domenig, Katja [Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Weber, Michael [Department of Biomedical Imaging and Image-Guided Therapy, Division of General and Pediatric Radiology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Kapetas, Panagiotis; Bernathova, Maria; Baltzer, Pascal A.T. [Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria)

    2016-12-15

    Highlights: • Wide scan-angle DBT alone shows a high detection rate for microcalcifications. • DBT and FFDM can characterize microcalcifications at a comparable level. • Characterization is influenced by reader and by lesion type (benign vs malignant). • DBT might be used as a stand-alone technique for the assessment of microcalcifications. - Abstract: Objectives: To assess the diagnostic performance of digital breast tomosynthesis (DBT), with a wide scan-angle, compared to full-field digital mammography (FFDM), for the detection and characterization of microcalcifications. Methods: IRB approval was obtained for this retrospective study. We selected 150 FFDM and DBT (50 benign and 50 malignant histologically verified microcalcifications, 50 cases classified as BI-RADS 1). Four radiologists evaluated, in separate sessions and blinded to patients’ history and histology, the presence of microcalcifications. Cases with microcalcifications were assessed for visibility, characteristics, and grade of suspicion using BI-RADS categories. Detection rate and diagnostic performance were calculated. Visibility, lesions’ characteristics and reading time were analysed. Results: Detection rate and visibility were good for both FFDM and DBT, without intra-reader differences (P = 0.510). Inter-reader differences were detected (P < 0.018). Only two lesions were not detected by any reader on either FFDM or DBT. Diagnostic performance with DBT was as good as that of FFDM, but a significant inter-reader difference was found (P = 0.041). High inter-reader variability in the use of the descriptors was found. Reading time for DBT was almost twice that for FFDM (44 and 25 s, respectively). Conclusion: Wide scan-angle DBT enabled the detection and characterization of microcalcifications with no significant differences from FFDM. Inter-reader variability was seen.

  12. A methodology to evaluate differential costs of full field digital as compared to conventional screen film mammography in a clinical setting

    International Nuclear Information System (INIS)

    Ciatto, S.; Brancato, B.; Baglioni, R.; Turci, M.

    2006-01-01

    Purpose: The use of full field digital mammography (FFDM) in alternative to conventional screen film mammography (SFM) in the current practice is delayed by the high costs of FFDM. The present study, performed at the Centro per lo Studio e la Prevenzione Oncologica of Florence, using both FFDM and SFM, was aimed at estimating the impact of introducing the new FFDM technique on overall mammography costs. Material and methods: We estimated the differential costs of both methods, based on real expenditures, as provided by the administrative department, and on radiologists, radiographers and other staff's working time. Two different workload scenarios (5000 and 10,000 tests/year per mammography equipment) were considered. Common costs of both techniques were censored for study purpose. Results: Beside a higher cost due to purchase and hire/leasing costs of equipment, FFDM implies a greater workload for radiologists (reading time almost doubled). SFM implies a greater workload for the administrative staff to run the archive and for loading/unloading films of the roller viewer, whereas no different workload has been observed for radiographers. Overall FFDM costs Euro 24.22-26.46 for examination more than SFM for the 5000 tests scenario and Euro 9.91-12.15 more for the 10,000 tests scenario. Discussion: Although present study estimates cannot easily be generalised to any local setting, the model for cost calculation is easy to be exported to another scenario by applying different local parameters. The advantages made available by FFDM (computerised data recording, tele-transmission, tele-reporting, tele-consulting, automatic display on monitor of previous exams and use of CAD) may justify the higher cost, but a limited reduction in purchase and assistance costs could easily allow a turnover, with FFDM being more convenient than SFM even on the cost side

  13. Deep-water Reservoir Modelling Using a volume-based approach on Full-Offset Seismic Data: Etim Field, Offshore Nigeria

    International Nuclear Information System (INIS)

    Nwaeri, E.; Zimbrick, G.; Proett, B.

    2002-01-01

    Reservoir characterization of deep-water deposits is a challenging task. Major issues to address include: (1) prediction of sand distribution away from well control, (2) definition of reservoir geometry and size, and (3) spatial placement of sand bodies in the geologic model. In a typical deep-water setting, lithostratigraphic correlation using well logs has been found to be unreliable. Seismic correlation is critical, but complications from mixed-impedance reservoir, and variations in frequency/phase content of available full stack data can arise.We describe a reservoir description workflow that utilizes both volume-and map-based conditioning tools, in the absence of AVO products. A good density of interpreted horizons was used to provide stratigraphic control on the volume interpretation techniques. Map pattern analysis of horizon slices helped focus environment of deposition (EOD) interpretations on key areas of reservoir development.A seismic wedge model helped develop an interpretation strategy and assess seismic data quality. Results showed that seed detection of trough-peak pairs gave a reasonable prediction of reservoir distribution at Etim.Seismic attributes were used to calibrate and predict net sand thickness. The predictions were integrated with EOD maps and well control to provide final net sand maps. Extracted geobodies from the sculpted seismic data were used to place sands in their proper position in the geologic model.The resulting geologic model preserves spatial positioning of the seismically derived reservoir elements and provides better definition of reservoir connectivity. This workflow is appropriate for fields where multi-volume (AVO) seismic data are unavailable and 3-D positioning of reservoir elements is required

  14. Which Phantom Is Better for Assessing the Image Quality in Full-Field Digital Mammography?: American College of Radiology Accreditation Phantom versus Digital Mammography Accreditation Phantom

    International Nuclear Information System (INIS)

    Song, Sung Eun; Seo, Bo Kyoung; Ku, Bon Kyung; Kim, Hee Young; Cho, Kyu Ran; Chung, Hwan Hoon; Lee, Seung Hwa; Hwang, Kyu Won; Yie, An

    2012-01-01

    To compare between the American College of Radiology (ACR) accreditation phantom and digital mammography accreditation phantom in assessing the image quality in full-field digital mammography (FFDM). In each week throughout the 42-week study, we obtained phantom images using both the ACR accreditation phantom and the digital mammography accreditation phantom, and a total of 42 pairs of images were included in this study. We assessed the signal-to-noise ratio (SNR) in each phantom image. A radiologist drew a square-shaped region of interest on the phantom and then the mean value of the SNR and the standard deviation were automatically provided on a monitor. SNR was calculated by an equation, measured mean value of SNR-constant coefficient of FFDM/standard deviation. Two breast radiologists scored visible objects (fibers, specks, and masses) with soft-copy images and calculated the visible rate (number of visible objects/total number of objects). We compared SNR and the visible rate of objects between the two phantoms and calculated the k-coefficient for interobserver agreement. The SNR of the ACR accreditation phantom ranged from 42.0 to 52.9 (Mean, 47.3 ± 2.79) and that of Digital Phantom ranged from 24.8 to 54.0 (Mean, 44.1 ± 9.93) (p = 0.028). The visible rates of all three types of objects were much higher in the ACR accreditation phantom than those in the digital mammography accreditation phantom (p < 0.05). Interobserver agreement for visible rates of objects on phantom images was fair to moderate agreement (k-coefficients: 0.34-0.57). The ACR accreditation phantom is superior to the digital mammography accreditation phantom in terms of SNR and visibility of phantom objects. Thus, ACR accreditation phantom appears to be satisfactory for assessing the image quality in FFDM.

  15. Interval breast cancer characteristics before, during and after the transition from screen-film to full-field digital screening mammography.

    Science.gov (United States)

    van Bommel, Rob M G; Weber, Roy; Voogd, Adri C; Nederend, Joost; Louwman, Marieke W J; Venderink, Dick; Strobbe, Luc J A; Rutten, Matthieu J C; Plaisier, Menno L; Lohle, Paul N; Hooijen, Marianne J H; Tjan-Heijnen, Vivianne C G; Duijm, Lucien E M

    2017-05-05

    To determine the proportion of "true" interval cancers and tumor characteristics of interval breast cancers prior to, during and after the transition from screen-film mammography screening (SFM) to full-field digital mammography screening (FFDM). We included all women with interval cancers detected between January 2006 and January 2014. Breast imaging reports, biopsy results and breast surgery reports of all women recalled at screening mammography and of all women with interval breast cancers were collected. Two experienced screening radiologists reviewed the diagnostic mammograms, on which the interval cancers were diagnosed, as well as the prior screening mammograms and determined whether or not the interval cancer had been missed on the most recent screening mammogram. If not missed, the cancer was considered an occult ("true") interval cancer. A total of 442 interval cancers had been diagnosed, of which 144 at SFM with a prior SFM (SFM-SFM), 159 at FFDM with a prior SFM (FFDM-SFM) and 139 at FFDM with a prior FFDM (FFDM-FFDM). The transition from SFM to FFDM screening resulted in the diagnosis of more occult ("true") interval cancers at FFDM-SFM than at SFM-SFM (65.4% (104/159) versus 49.3% (71/144), P mammography. However, this increase seems temporary and is no longer detectable after the second round of digital screening. Tumor characteristics and type of surgery are comparable for interval cancers detected prior to, during and after the transition from SFM to FFDM screening mammography, except of a lower proportion of invasive ductal cancers after the transition.

  16. Two-view digital breast tomosynthesis screening with synthetically reconstructed projection images: comparison with digital breast tomosynthesis with full-field digital mammographic images.

    Science.gov (United States)

    Skaane, Per; Bandos, Andriy I; Eben, Ellen B; Jebsen, Ingvild N; Krager, Mona; Haakenaasen, Unni; Ekseth, Ulrika; Izadi, Mina; Hofvind, Solveig; Gullien, Randi

    2014-06-01

    To compare the performance of two versions of reconstructed two-dimensional (2D) images in combination with digital breast tomosynthesis (DBT) versus the performance of standard full-field digital mammography (FFDM) plus DBT. This trial had ethical committee approval, and all participants gave written informed consent. Examinations (n = 24 901) in women between the ages of 50 and 69 years (mean age, 59.2 years) were interpreted prospectively as part of a screening trial that included independent interpretations of FFDM plus DBT and reconstructed 2D images plus DBT. Reconstructed 2D images do not require radiation exposure. Using analyses for binary data that accounted for correlated interpretations and were adjusted for reader-specific volume, two versions (initial and current) of reconstructed 2D images used during trial periods 1 (from November 22, 2010, to December 21, 2011; 12 631 women) and 2 (from January 20, 2012, to December 19, 2012; 12 270 women) were compared in terms of cancer detection and false-positive rates with the corresponding FFDM plus DBT interpretations. Cancer detection rates were 8.0, 7.4, 7.8, and 7.7 per 1000 screening examinations for FFDM plus DBT in period 1, initial reconstructed 2D images plus DBT in period 1, FFDM plus DBT in period 2, and current reconstructed 2D images plus DBT in period 2, respectively. False-positive scores were 5.3%, 4.6%, 4.6%, and 4.5%, respectively. Corresponding reader-adjusted paired comparisons of false-positive scores revealed significant differences for period 1 (P = .012) but not for period 2 (ratio = 0.99; 95% confidence interval: 0.88, 1.11; P = .85). The combination of current reconstructed 2D images and DBT performed comparably to FFDM plus DBT and is adequate for routine clinical use when interpreting screening mammograms.

  17. Full-color wide field-of-view holographic helmet-mounted display for pilot/vehicle interface development and human factors studies

    Science.gov (United States)

    Burley, James R., II; LaRussa, Joseph A.

    1990-10-01

    A Helmet-Mounted Display (HMD) which utilizes highly efficient trichromatic holographic elements has been designed to support pilot vechicle interface development and human factors studies at the NASA-Langley Research Center. While the optics are fully color corrected, the miniature CRT's are monochromatic. This design provides an upgrade path to full-color when miniature display technology matures to color. The optical design conforms to the helmet shape and provides a 50 degree field-of-view (FOV) to each eye. Built-in adjustments allow each ocular to be independently moved so that the overall horizontal FOV may be varied from 50 degrees to 100 degrees with a corresponding change in the stereo overlap region. The helmet design and interpupillary adjustment allow for the 5th through 95th percentile male and female wearer. Total head-borne weight is approximately 4.2 pounds. The high-resolution monochromatic CRTs are driven by a set of multisync electronics with a maximum video bandwidth of 88 Mhz and supports bith raster and stroke modes. The electronics are designed to be compatiable with the Silicon Graphics IRIS 4D graphics workstations and the ADAGE 340 stroke graphics computer. A Polhemus magnetic tracking device is used to determine the helmet line-of-sight. The helmet will be used to develop innovative new display concepts for the F- 1 8 High-Alpha Research Vehicle (HARV) which make use of the unique display properties of the HMD. Pictorial displays, which convey the appropriate information intuitively, are envisioned. Human factors studies are also planned to evaluate the utility of stereopsis and determine the FOV requirements for different tasks. Concepts proven in the simulator will be carried to flight test in 1993 with a lighter weight, "hardened" version of this HMD design.

  18. Automatic Estimation of Volumetric Breast Density Using Artificial Neural Network-Based Calibration of Full-Field Digital Mammography: Feasibility on Japanese Women With and Without Breast Cancer.

    Science.gov (United States)

    Wang, Jeff; Kato, Fumi; Yamashita, Hiroko; Baba, Motoi; Cui, Yi; Li, Ruijiang; Oyama-Manabe, Noriko; Shirato, Hiroki

    2017-04-01

    Breast cancer is the most common invasive cancer among women and its incidence is increasing. Risk assessment is valuable and recent methods are incorporating novel biomarkers such as mammographic density. Artificial neural networks (ANN) are adaptive algorithms capable of performing pattern-to-pattern learning and are well suited for medical applications. They are potentially useful for calibrating full-field digital mammography (FFDM) for quantitative analysis. This study uses ANN modeling to estimate volumetric breast density (VBD) from FFDM on Japanese women with and without breast cancer. ANN calibration of VBD was performed using phantom data for one FFDM system. Mammograms of 46 Japanese women diagnosed with invasive carcinoma and 53 with negative findings were analyzed using ANN models learned. ANN-estimated VBD was validated against phantom data, compared intra-patient, with qualitative composition scoring, with MRI VBD, and inter-patient with classical risk factors of breast cancer as well as cancer status. Phantom validations reached an R 2 of 0.993. Intra-patient validations ranged from R 2 of 0.789 with VBD to 0.908 with breast volume. ANN VBD agreed well with BI-RADS scoring and MRI VBD with R 2 ranging from 0.665 with VBD to 0.852 with breast volume. VBD was significantly higher in women with cancer. Associations with age, BMI, menopause, and cancer status previously reported were also confirmed. ANN modeling appears to produce reasonable measures of mammographic density validated with phantoms, with existing measures of breast density, and with classical biomarkers of breast cancer. FFDM VBD is significantly higher in Japanese women with cancer.

  19. Full-field digital mammography: Is the apparent increased detection of microcalcification leading to over-investigation and over-diagnosis?

    Science.gov (United States)

    Porter, Alan J; Evans, Elizabeth B; Erzetich, Lisa M

    2017-08-01

    Modern full-field digital mammography (FFDM) appears to have increased the detection of breast microcalcification. This retrospective study aimed to assess whether this is associated with over-investigation and possible over-diagnosis of breast pathology of lesser significance. Three 2-year periods were studied, in which different mammographic technologies were used exclusively viz., classical screen-film mammography (SFM) in 2003-04, computed radiography (CR) in 2009-10 and FFDM in 2012-13. The study was limited to women in whom biopsy was done for indeterminate, suspicious or malignant (ISM) calcification as the only mammographic abnormality. Between the first and the third time periods, the use of core biopsies and vacuum-assisted biopsies (VABs) for 'ISM calcification only' increased from 0. 6% to 1.4% of all mammograms, and biopsies with malignant results increased from 0.18% to 0.33% of all mammograms. VAB became the preferred technique for biopsy over the study period. The proportion of cores and VABs with a malignant result did not change significantly over the three time periods (24-28%), nor did the proportion of invasive cancers, ductal carcinoma in situ (DCIS) (60-63%) or atypia on subsequent excision. The proportion of DCIS which was of high grade was greatest in the FFDM era (69%). Less than 9% of DCIS were of low grade in all three time periods. Despite increased numbers of biopsies being performed, there was no increase in findings of breast pathology of lesser significance. Improved technology (FFDM and VAB) allows immediate biopsy of small clusters of indeterminate microcalcification, rather than using mammographic surveillance, and this study found no evidence that this has been associated with over-investigation or over-diagnosis. © 2017 The Royal Australian and New Zealand College of Radiologists.

  20. Estimation of percentage breast tissue density: comparison between digital mammography (2D full field digital mammography) and digital breast tomosynthesis according to different BI-RADS categories

    Science.gov (United States)

    Cavagnetto, F; Calabrese, M; Houssami, N

    2013-01-01

    Objective: To compare breast density estimated from two-dimensional full-field digital mammography (2D FFDM) and from digital breast tomosynthesis (DBT) according to different Breast Imaging–Reporting and Data System (BI-RADS) categories, using automated software. Methods: Institutional review board approval and written informed patient consent were obtained. DBT and 2D FFDM were performed in the same patients to allow within-patient comparison. A total of 160 consecutive patients (mean age: 50±14 years; mean body mass index: 22±3) were included to create paired data sets of 40 patients for each BI-RADS category. Automatic software (MedDensity©, developed by Giulio Tagliafico) was used to compare the percentage breast density between DBT and 2D FFDM. The estimated breast percentage density obtained using DBT and 2D FFDM was examined for correlation with the radiologists' visual BI-RADS density classification. Results: The 2D FFDM differed from DBT by 16.0% in BI-RADS Category 1, by 11.9% in Category 2, by 3.5% in Category 3 and by 18.1% in Category 4. These differences were highly significant (pBI-RADS categories and the density evaluated using 2D FFDM and DBT (r=0.56, pBI-RADS categories. These data are relevant for clinical practice and research studies using density in determining the risk. Advances in knowledge: On DBT, breast density values were lower than with 2D FFDM, with a non-linear relationship across the classical BI-RADS categories. PMID:24029631

  1. Application of a simplified calculation for full-wave microtremor H/ V spectral ratio based on the diffuse field approximation to identify underground velocity structures

    Science.gov (United States)

    Wu, Hao; Masaki, Kazuaki; Irikura, Kojiro; Sánchez-Sesma, Francisco José

    2017-12-01

    Under the diffuse field approximation, the full-wave (FW) microtremor H/ V spectral ratio ( H/ V) is modeled as the square root of the ratio of the sum of imaginary parts of the Green's function of the horizontal components to that of the vertical one. For a given layered medium, the FW H/ V can be well approximated with only surface waves (SW) H/ V of the "cap-layered" medium which consists of the given layered medium and a new larger velocity half-space (cap layer) at large depth. Because the contribution of surface waves can be simply obtained by the residue theorem, the computation of SW H/ V of cap-layered medium is faster than that of FW H/ V evaluated by discrete wavenumber method and contour integration method. The simplified computation of SW H/ V was then applied to identify the underground velocity structures at six KiK-net strong-motion stations. The inverted underground velocity structures were used to evaluate FW H/ Vs which were consistent with the SW H/ Vs of corresponding cap-layered media. The previous study on surface waves H/ Vs proposed with the distributed surface sources assumption and a fixed Rayleigh-to-Love waves amplitude ratio for horizontal motions showed a good agreement with the SW H/ Vs of our study. The consistency between observed and theoretical spectral ratios, such as the earthquake motions of H/ V spectral ratio and spectral ratio of horizontal motions between surface and bottom of borehole, indicated that the underground velocity structures identified from SW H/ V of cap-layered medium were well resolved by the new method.[Figure not available: see fulltext.

  2. Estimation of percentage breast tissue density: comparison between digital mammography (2D full field digital mammography) and digital breast tomosynthesis according to different BI-RADS categories.

    Science.gov (United States)

    Tagliafico, A S; Tagliafico, G; Cavagnetto, F; Calabrese, M; Houssami, N

    2013-11-01

    To compare breast density estimated from two-dimensional full-field digital mammography (2D FFDM) and from digital breast tomosynthesis (DBT) according to different Breast Imaging-Reporting and Data System (BI-RADS) categories, using automated software. Institutional review board approval and written informed patient consent were obtained. DBT and 2D FFDM were performed in the same patients to allow within-patient comparison. A total of 160 consecutive patients (mean age: 50±14 years; mean body mass index: 22±3) were included to create paired data sets of 40 patients for each BI-RADS category. Automatic software (MedDensity(©), developed by Giulio Tagliafico) was used to compare the percentage breast density between DBT and 2D FFDM. The estimated breast percentage density obtained using DBT and 2D FFDM was examined for correlation with the radiologists' visual BI-RADS density classification. The 2D FFDM differed from DBT by 16.0% in BI-RADS Category 1, by 11.9% in Category 2, by 3.5% in Category 3 and by 18.1% in Category 4. These differences were highly significant (pBI-RADS categories and the density evaluated using 2D FFDM and DBT (r=0.56, pBI-RADS categories. These data are relevant for clinical practice and research studies using density in determining the risk. On DBT, breast density values were lower than with 2D FFDM, with a non-linear relationship across the classical BI-RADS categories.

  3. Estudo normativo do eletrorretinograma de campo total em adultos jovens Normative values for full-field electroretinogram in healthy young adults

    Directory of Open Access Journals (Sweden)

    Josenilson Martins Pereira

    2003-01-01

    Full Text Available OBJETIVOS: A proposta deste estudo é estabelecer valores normativos para o eletrorretinograma (ERG de campo total, em um grupo de voluntários adultos jovens segundo o protocolo padrão recomendado pela Sociedade Internacional de Eletrofisiologia Visual Clínica (ISCEV. MÉTODOS: Participaram deste estudo 42 voluntários normais com idades variando de 15 a 26 anos, sendo 20 homens e 22 mulheres. Os eletrorretinogramas de campo total foram obtidos com eletrodos de lente de contato bipolares e seguiram as 5 etapas do protocolo da Sociedade Internacional de Eletrofisiologia Visual Clinica: a resposta de bastonetes; b reposta máxima; c potenciais oscilatórios; d resposta máxima de cones; e resposta de cones ao flicker 30 Hz. Os parâmetros analisados foram a amplitude de resposta do pico da onda-a até o pico da onda-b (pico a pico em miV e o tempo de culminação da onda-b (ms. RESULTADOS: As médias (± 1 desvio padrão da amplitude pico a pico foram: resposta de bastonetes - 241,1 ± 66,9 µV; resposta máxima - 385,4 ± 71,8 µV; potenciais oscilatórios - 180,6 ± 48,6 µV; resposta de cones -102,8 ± 36,3 µV e flicker 30 Hz - 69,2 ± 26,6 µV. Para o tempo implícito da onda-b os valores foram: resposta de bastonetes - 85,2 ± 7,6 ms; resposta máxima -45,6 ± 2,0ms; resposta de cones - 27,8 ± 1,2ms e flicker 30 Hz - 27,9 ± 1,2 ms. Os resultados foram comparáveis entre os grupos masculino e feminino, exceto para a resposta máxima em que as mulheres obtiveram amplitudes estatisticamente maiores (t=2,06; P=0,046. CONCLUSÃO: Os valores encontrados estão de acordo com dados normativos da literatura e são fundamentais para o diagnóstico correto de disfunções retinianas em pacientes na mesma faixa etária. Inclusão de outras faixas etárias e o aumento no número de sujeitos testados são necessários para estender valores normativos para o eletrorretinograma.PURPOSE: To determine normative data for full-field electroretinogram (ERG

  4. Padronização do eletrorretinograma de campo total em cães Full field electrorretinogram standartization in dogs

    Directory of Open Access Journals (Sweden)

    Angélica M.V. Safatle

    2010-09-01

    ável quando se objetiva comparar resultados de laboratórios distintos. A confiabilidade e reprodutibilidade deste protocolo foi demonstrada com a obtenção de registros de ótima qualidade utilizando protocolo padrão da ISCEV, eletrorretinógrafo Veris, Ganzfeld e eletrodos Burian Allen nos cães submetidos à sedação.Electroretinogram (ERG is an objective non invasive diagnostic method to evaluate retinal function which permits the early detection of lesions at retinal external layers, even before the appearance of clinical signs. In dogs, ERG is mostly utilized for preoperative evaluation in patients presenting cataracts; characterization of disturbances causing blindness, among the utilization of dogs as animal models in scientific research. Several factors interfere in ERG responses, such as the ERG machine, light stimulation, electrode, time spent on dark adaptation, pupil size, means opacity, sedation or anesthetization, species, breed and age. The purpose of this study was to standardize the full field ERG in sedated dogs, according to the International Society for Clinical Electrophysiology of Vision (ISCEV protocol, using Ganzfeld and bipolar electrodes. Two hundred thirty threes ERGs were performed in 147 female and 86 male with ages from 1 to 14 years old. Among those 233 dogs, 100 presented cataracts in different stages of maturation, 72 were diabetic and presented mature or hypermature cataracts, 26 presented ERG compatible to progressive retinal degeneration, 3 presented ERG compatible to sudden acquired retinal degeneration syndrome; for 32 dogs no abnormal ERG was registered and they were considered as having normal retinal function. Sedation was capable to induce a good immobilization with no bulb rotation, resulting uniform retinal stimulation, using Ganzfeld. Veris system successfully registered all 5 ISCEV responses, simultaneously from both eyes, at the same time. Full field ERG became a fundamental ophthalmic exam, then, its standardization is

  5. Effect of the Availability of Prior Full-Field Digital Mammography and Digital Breast Tomosynthesis Images on the Interpretation of Mammograms.

    Science.gov (United States)

    Hakim, Christiane M; Catullo, Victor J; Chough, Denise M; Ganott, Marie A; Kelly, Amy E; Shinde, Dilip D; Sumkin, Jules H; Wallace, Luisa P; Bandos, Andriy I; Gur, David

    2015-07-01

    To assess the effect of and interaction between the availability of prior images and digital breast tomosynthesis (DBT) images in decisions to recall women during mammogram interpretation. Verbal informed consent was obtained for this HIPAA-compliant institutional review board-approved protocol. Eight radiologists independently interpreted twice deidentified mammograms obtained in 153 women (age range, 37-83 years; mean age, 53.7 years ± 9.3 [standard deviation]) in a mode by reader by case-balanced fully crossed study. Each study consisted of current and prior full-field digital mammography (FFDM) images and DBT images that were acquired in our facility between June 2009 and January 2013. For one reading, sequential ratings were provided by using (a) current FFDM images only, (b) current FFDM and DBT images, and (c) current FFDM, DBT, and prior FFDM images. The other reading consisted of (a) current FFDM images only, (b) current and prior FFDM images, and (c) current FFDM, prior FFDM, and DBT images. Fifty verified cancer cases, 60 negative and benign cases (clinically not recalled), and 43 benign cases (clinically recalled) were included. Recall recommendations and interaction between the effect of prior FFDM and DBT images were assessed by using a generalized linear model accounting for case and reader variability. Average recall rates in noncancer cases were significantly reduced with the addition of prior FFDM images by 34% (145 of 421) and 32% (106 of 333) without and with DBT images, respectively (P images resulted in a smaller reduction in recall rates (false-positive interpretations) of 19% (76 of 409) and 26% (71 of 276) without and with prior FFDM images, respectively (P = .001). Availability of DBT images resulted in 4% (15 of 338) and 8% (25 of 322) increases in sensitivity, respectively (P = .007). The effects of the availability of prior FFDM images or DBT images did not significantly change regardless of the sequence in presentation (P = .81 and P

  6. Computer-aided detection of microcalcification clusters on full-field digital mammograms: multiscale pyramid enhancement and false positive reduction using an artificial neural network

    Science.gov (United States)

    Ge, Jun; Wei, Jun; Hadjiiski, Lubomir M.; Sahiner, Berkman; Chan, Heang-Ping; Helvie, Mark A.; Zhou, Chuan

    2005-04-01

    We are developing a computer-aided detection (CAD) system to detect microcalcification clusters automatically on full field digital mammograms (FFDMs). The CAD system includes five stages: preprocessing, image enhancement and/or box-rim filtering, segmentation of microcalcification candidates, false positive (FP) reduction, and clustering. In this study, we investigated the performance of a nonlinear multiscale Laplacian pyramid enhancement method in comparison with a box-rim filter at the image enhancement stage and the use of a new error metric to improve the efficiency and robustness of the training of a convolution neural network (CNN) at the FP reduction stage of our CAD system. A data set of 96 cases with 200 images was collected at the University of Michigan. This data set contained 215 microcalcification clusters, of which 64 clusters were proven by biopsy to be malignant and 151 were proven to be benign. The data set was separated into two independent data sets. One data set was used to train and validate the CNN in our CAD system. The other data set was used to evaluate the detection performance. For this data set, Laplacian pyramid multiscale enhancement did not improve the performance of the microcalcification detection system in comparison with our box-rim filter previously optimized for digitized screen-film mammograms. With the new error metric, the training of CNN could be accelerated and the classification performance in validation was improved from an Az value of 0.94 to 0.97 on average. The CNN in combination with rule-based classifiers could reduce FPs with a small tradeoff in sensitivity. By using the free-response receiver operating characteristic (FROC) methodology, it was found that our CAD system can achieve a cluster-based sensitivity of 70%, 80%, and 88% at 0.23, 0.39, and 0.71 FP marks/image, respectively. For case-based performance evaluation, a sensitivity of 80%, 90%, and 98% can be achieved at 0.17, 0.27, and 0.51 FP marks

  7. Magnetic field induced assembling of nanoparticles in ferrofluidic ...

    Indian Academy of Sciences (India)

    Unknown

    The effect of a magnetic field on these thin films will have a profound influence on the birefringent properties of these fluid films. If an external magnetic field is applied parallel to .... mission through ferrofluid thin film (Normal incidence and de- tection with respect to ... lation, only the Zeeman energy term (Ez = –µH cosθ) is.

  8. Demodulation of DPSK signals up to 40 Gb/s using a highly birefringent photonic bandgap fiber

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Geng, Yan; Zsigri, Beata

    2006-01-01

    Phase-to-intensity modulation conversion of differential phase-shift keying signals is successfully demonstrated at 10 and 40 Gb/s using a polarization Mach-Zehnder delay interferometer implemented with only 2.4 m of a highly birefringent air-guiding photonic bandgap (PBG) fiber. Such a PBG fiber...

  9. All-solid birefringent hybrid photonic crystal fiber based interferometric sensor for measurement of strain and temperature

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Scott Wu; Zhang, A. Ping

    2011-01-01

    A highly sensitive fiber-optic interferometric sensor based on an all-solid birefringent hybrid photonic crystal fiber (PCF) is demonstrated for measuring strain and temperature. A strain sensitivity of similar to 23.8 pm/mu epsilon and a thermal sensitivity of similar to-1.12 nm/degrees C...

  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. Follow-up and Final Results of the Oslo I Study Comparing Screen-Film Mammography and Full-field Digital Mammography with Soft-Copy Reading

    Energy Technology Data Exchange (ETDEWEB)

    Skaane, P.; Skjennald, A.; Young, K. [Ullevaal Univ. Hospital, Oslo (Norway). Dept. of Radiology] [and others

    2005-11-01

    Purpose: To compare cancer detection rates of screen-film (SFM) and full-field digital mammography (FFDM) with soft-copy reading in a screening program including the initial positive scores for interval cancers and cancers in the subsequent screening round, and to analyze the false-negative FFDM interpretations. Material and Methods: Using a paired study design, 3683 women underwent SFM and FFDM in a population-based screening program. Two standard views of each breast were acquired. The images were interpreted without previous films for comparison. Independent double reading using a 5-point rating scale for probability of cancer was used for each modality. An examination was defined as positive if at least one of the two independent readers scored 2 or higher on the 5-point rating scale. SFM-positive cases were discussed in a SFM consensus meeting and FFDM-positive cases in a separate FFDM consensus meeting before recall. The study population was followed for more than 2 years so that interval cancers and screen-detected cancers in the subsequent screening round could be included. Cancer detection rates were compared using the McNemar test for paired proportions. The kappa statistic and Wilcoxon signed-rank test for matched pairs were used for comparing rating scores. The reading time was recorded for all FFDM interpretations. Results: A total of 31 cancers (detection rate 0.84%) were diagnosed initially, of which SFM detected 28 and FFDM 23 (McNemar test P 0.23, discordant pair 8 and 3). Two cancers with a positive score at initial SFM reading and three with a positive score at initial FFDM reading were dismissed at SFM and FFDM consensus meetings, respectively. The difference in cancer detection after recall (discordant pair 11 and 5) was not significant (McNemar test, P = 0.21). Of the 10 interval cancers and 16 screen-detected cancers in the subsequent round, 3 had true-positive SFM scores while 4 had true-positive FFDM scores in the initial reading session. A

  12. Early experience in the use of quantitative image quality measurements for the quality assurance of full field digital mammography x-ray systems

    International Nuclear Information System (INIS)

    Marshall, N W

    2007-01-01

    Quantitative image quality results in the form of the modulation transfer function (MTF), normalized noise power spectrum (NNPS) and detective quantum efficiency (DQE) are presented for nine full field digital mammography (FFDM) systems. These parameters are routinely measured as part of the quality assurance (QA) programme for the seven FFDM units covered by our centre. Just one additional image is required compared to the standard FFDM protocol; this is the image of an edge, from which the MTF is calculated. A variance image is formed from one of the flood images used to measure the detector response and this provides useful information on the condition of the detector with respect to artefacts. Finally, the NNPS is calculated from the flood image acquired at a target detector air kerma (DAK) of 100 μGy. DQE is then estimated from these data; however, no correction is currently made for effects of detector cover transmission on DQE. The coefficient of variation (cov) of the 50% point of the MTF for five successive MTF results was 1%, while the cov for the 50% MTF point for an a-Se system over a period of 17 months was approximately 3%. For four a-Se based systems, the cov for the NNPS at 1 mm -1 for a target DAK of 100 μGy was approximately 4%; the same result was found for four CsI based FFDM units. With regard to the stability of NNPS over time, the cov for four NNPS results acquired over a period of 12 months was also approximately 4%. The effect of acquisition geometry on NNPS was also assessed for a CsI based system. NNPS data acquired with the antiscatter grid in place showed increased noise at low spatial frequency; this effect was more severe as DAK increased. DQE results for the three detector types (a-Se, CsI and CR) are presented as a function of DAK. Some reduction in DQE was found for both the a-Se and CsI based systems at a target DAK of 12.5 μGy when compared to DQE data acquired at 100 μGy. For the CsI based systems, DQE at 1 mm -1 fell from 0

  13. Birefringent static Fourier-transform spectrometer for flow cytometry and imaging spectroscopy.

    Science.gov (United States)

    Hegyi, Alex

    2017-07-24

    A new concept for a birefringent static Fourier-transform spectrometer, applicable to both spectral flow cytometry and hyperspectral imaging, is introduced. Biological particles or scenes in relative motion are imaged onto a polarization interferometer consisting of a calcite Wollaston prism between crossed polarizers, with polarization axes at 45° with respect to the optical axes of the Wollaston prism. Due to the position-dependent optical path delay of the interferometer, interferograms are generated by the relative motion. These interferograms are recorded either by a flow cytometer detector, or in the case of hyperspectral imaging, by a CMOS focal plane array. Fourier-transforming the interferograms with respect to time yields the optical spectrum of each particle or scene position. The concept has applicability to situations where linear motion is already present, including flow cytometers, conveyor belt systems, fixed-wing aircraft, and nanosatellites.

  14. Soliton-mediated orientational ordering of gold nanorods and birefringence in plasmonic suspensions.

    Science.gov (United States)

    Ren, Yu-Xuan; Kelly, Trevor S; Zhang, Chensong; Xu, Huizhong; Chen, Zhigang

    2017-02-01

    We report on the soliton-mediated orientational ordering of gold nanorods in a colloidal plasmonic suspension. Due to the nonlinear optical response of the suspension, a light beam forms an optical spatial soliton which creates an effective optical waveguide. The orientation of the nanorods along the waveguide is regulated by the optical torque exerted by the linearly polarized soliton beam. By measuring the polarization transmission spectrum of a probe beam at a wavelength far from the plasmonic resonance, we observe orientation-enhanced birefringence along the soliton channel, suggesting a disorder-to-order transition of nanorods due to the action of the soliton beam. This approach may be applied in other colloidal systems with optical force-induced nonlinearity.

  15. Semiconductor optical amplifier direct modulation with double-stage birefringent fiber loop

    Science.gov (United States)

    Engel, Thomas; Rizou, Zoe V.; Zoiros, Kyriakos E.; Morel, Pascal

    2016-06-01

    The feasibility of cascading two birefringent fiber loops (BFLs) for directly modulating a conventional semiconductor optical amplifier (SOA) at a faster data rate than that being possible by its limited electrical bandwidth is demonstrated for the first time. The experimental results reveal the improvements in the quality characteristics of the encoded signal compared to those achieved with a single-stage BFL. The observed trends are complemented by numerical simulations, which allow to investigate the impact of the double-stage BFL detuning and specify how this critical parameter must be selected for enhanced performance. Provided that it is properly tailored, the proposed optical notch filtering scheme efficiently compensates for the pattern-dependent SOA response and enables this element to be employed as intensity modulator with improved performance at enhanced data speeds.

  16. 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)

  17. ARTICLES: Polarization effects in birefringent fiber waveguides with an elliptic borosilicate cladding

    Science.gov (United States)

    Grigor'yants, V. V.; Zalogin, A. N.; Ivanov, G. A.; Isaev, Victor A.; Kozel, S. M.; Listvin, V. N.; Chamorovskiĭ, Yu K.

    1986-10-01

    Single-mode fiber waveguides with an elliptic borosilicate cladding were developed and their polarization characteristics were studied. It was found that the mode birefringence was independent of the radiation frequency and varied linearly with the fiber waveguide temperature. The length of the beats was ~10 mm at λ = 0.85μ, whereas the dispersion of the polarization modes was 300 psec/km. The losses were 5-10 dB/km at λ = 0.85μ and the mode coupling parameter was h = 2×10-4m-1. A study was made of the possibility of using single-mode fiber waveguides for the depolarization of nonmonochromatic radiation and also as tunable delay lines.

  18. Polarization effects in birefringent fiber-optic waveguides with an elliptical borosilicate cladding

    Science.gov (United States)

    Grigoriants, V. V.; Zalogin, A. N.; Ivanov, G. A.; Isaev, V. A.; Kozel, S. M.

    1986-10-01

    Single-mode fiber-optic waveguides (SFW) with an elliptical borosilicate cladding are developed and their polarization characteristics are studied. It is shown that their mode birefringence, while independent of the radiation frequency, depends linearly on the SFW temperature. The beat length is about 10 mm at a wavelength of 0.85 micron and the dispersion of the polarization modes is about 300 ps/km. The losses amount to 5-10 dB/km at 0.85 micron and the mode coupling parameter is 0.0002/m. Consideration is given to the possibility of using SFW for the depolarization of nonmonochromatic radiation and as tunable delay lines.

  19. Theory and computation of the matrix elements of the full interaction of the electromagnetic field with an atomic state: Application to the Rydberg and the continuous spectrum

    International Nuclear Information System (INIS)

    Komninos, Yannis; Mercouris, Theodoros; Nicolaides, Cleanthes A.

    2002-01-01

    We develop practical formulas for the calculation of the matrix elements of the interaction of the electromagnetic field with an atomic state, beyond the long-wavelength approximation. The atom-plus-field Hamiltonian is chosen to have the multipolar form, containing the electric, paramagnetic, and diamagnetic operators. The final workable expressions include the interactions to all orders and are derived by first expanding the fields in partial waves. The electric-field operator reaches a constant value as the radial variable becomes large, contrary to the result of the electric-dipole approximation (EDA) where the value of the corresponding operator increases indefinitely. Applications are given for Rydberg states of hydrogen up to n=50 and for free-free transitions in a Coulomb potential. Such matrix elements are relevant to a number of real and virtual processes occurring during laser-atom interactions. The computation is done numerically, using a combination of analytic with numerical techniques. By comparing the results of the EDA with those of the exact treatment, it is shown that the former is inadequate in such cases. This finding has repercussions on the theory and understanding of the physics of quantum systems in high-lying Rydberg levels and wave packets or in scattering states

  20. Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

    OpenAIRE

    Liu, Xinming; Shaw, Chris C.; Lai, Chao-Jen; Wang, Tianpeng

    2010-01-01

    Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging.

  1. 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.

  2. First demonstration and field trial on multi-user UDWDM-PON full duplex PSK-PSK with single monolithic integrated dual-output-DFB-SOA based ONUs.

    Science.gov (United States)

    Chu, GuangYong; Maho, Anaëlle; Cano, Iván; Polo, Victor; Brenot, Romain; Debrégeas, Hélène; Prat, Josep

    2016-10-15

    We demonstrate a monolithically integrated dual-output DFB-SOA, and conduct the field trial on a multi-user bidirectional coherent ultradense wavelength division multiplexing-passive optical network (UDWDM-PON). To the best of our knowledge, this is the first achievement of simplified single integrated laser-based neighboring coherent optical network units (ONUs) with a 12.5 GHz channel spaced ultra-dense access network, including both downstream and upstream, taking the benefits of low footprint and low-temperature dependence.

  3. High-resolution NMR field-cycling device for full-range relaxation and structural studies of biopolymers on a shared commercial instrument

    International Nuclear Information System (INIS)

    Redfield, Alfred G.

    2012-01-01

    Improvements are described in a shuttling field-cycling device (Redfield in Magn Reson Chem 41:753–768, 2003), designed to allow widespread access to this useful technique by configuring it as a removable module to a commercial 500 MHz NMR instrument. The main improvements described here, leading to greater versatility, high reliability and simple construction, include: shuttling provided by a linear motor driven by an integrated-control servomotor; provision of automated bucking magnets to allow fast two-stage cycling to nearly zero field; and overall control by a microprocessor. A brief review of history and publications that have used the system is followed by a discussion of topics related to such a device including discussion of some future applications. A description of new aspects of the shuttling device follows. The minimum round trip time to 1T and above is less than 0.25 s and to 0.002 T is 0.36 s. Commercial probes are used and sensitivity is that of the host spectrometer reduced only by relaxation during travel. A key element is development of a linkage that prevents vibration of the linear motor from reaching the probe.

  4. 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.

  5. The Sensitivity of Atmospheric Dispersion Calculations in Near-field Applications: Modeling of the Full Scale RDD Experiments with Operational Models in Canada, Part I.

    Science.gov (United States)

    Lebel, Luke; Bourgouin, Pierre; Chouhan, Sohan; Ek, Nils; Korolevych, Volodymyr; Malo, Alain; Bensimon, Dov; Erhardt, Lorne

    2016-05-01

    Three radiological dispersal devices were detonated in 2012 under controlled conditions at Defence Research and Development Canada's Experimental Proving Grounds in Suffield, Alberta. Each device comprised a 35-GBq source of (140)La. The dataset obtained is used in this study to assess the MLCD, ADDAM, and RIMPUFF atmospheric dispersion models. As part one of a two-part study, this paper focuses on examining the capabilities of the above three models and evaluating how well their predictions of air concentration and ground deposition match observations from the full-scale RDD experiments.

  6. Digital mammography with high-resolution storage plates (CR) versus full-field digital mammography (CCD) (DR) for microcalcifications and focal lesions - a retrospective clinical histologic analysis (n = 102)

    International Nuclear Information System (INIS)

    Schulz-Wendtland, R.; Lell, M.; Wenkel, E.; Boehner, C.; Dassel, M.S.; Bautz, W.

    2005-01-01

    Purpose: to determine the diagnostic accuracy of microcalcifications and focal lesions in a retrospective clinical-histological study using high-resolution digital phosphor storage plates (hard copy) and full-field digital mammography (hard copy). Materials and methods: from May 2003 to September 2003, 102 patients underwent digital storage plate mammography (CR), using a mammography unit (Mammomat 3000 N, Siemens) in combination with a high resolution (9 lp/mm) digital storage phosphor plate system (pixel size 50 μm) (Fuji/Siemens). After diagnosis and preoperative wire localization, full-field digital mammography (CCD) (DR) was performed with the same exposure parameters. The full-field digital mammography used a CCD-detector (SenoScan) (fisher imaging) with a resolution of 10 Ip/mm and a pixel size of 50 μm. Five investigators determined the diagnosis (BI-RADS trademark I-V) retrospectively after the operation from randomly distributed mediolateral views (hard copy reading). These results were correlated with the final histology. Results: the diagnostic accuracy of digital storage plate mammography (CR) and full-field digital mammography (CCD) (DR) was 73% and 71% for all findings (n = 102), 73% and 71% for microcalcifications (n = 51), and 72% and 70% for focal lesions (n = 51). The overall results showed no difference. Conclusion: our findings indicate the equivalence of high-resolution digital phosphor storage plate mammography (CR) and full-field digital mammography (CCD) (DR). (orig.)

  7. Measurement of the magnetically-induced QED birefringence of the vacuum and an improved search for laboratory axions: Technical report. Project definition study of the use of assets and facilities of the Superconducting Super Collider Laboratory

    International Nuclear Information System (INIS)

    Lee, S.A.; Fairbank, W.M. Jr.; Toki, W.H.; Kraushaar, P.F. Jr.; Jaffery, T.S.

    1994-01-01

    The Colorado State Collaboration has studied the feasibility of a high sensitivity QED birefringence/axion search measurement. The objective of this work is to measure, for the first time, the birefringence induced in the vacuum on a light beam travelling in a powerful magnetic field. The same experimental setup also allows a highly sensitive search for axion or axion-like particles. The experiment would combined custom-designed optical heterodyne interferometry with a string of six SSC prototype superconducting dipole magnets at the N-15 site of the SSC Laboratory. With these powerful laser tools, sensitivity advances of 10 7 to 10 9 over previous optical experiments will be possible. The proposed experiment will be able to measure the QED light-by-light scattering effect with a 0.5% accuracy. The increased sensitivity for the axion-two photon interaction will result in a bound on this process rivaling the results based on astrophysical arguments. In the technical report the authors address the scientific significance of these experiments and examine the limiting technical parameters which control their feasibility. The proposed optical/electronic scheme is presented in the context of a background of the known and projected systematic problems which will confront any serious attempt to make such measurements

  8. Realization of a free-space 2 × 4 90° optical hybrid based on the birefringence and electro-optic effects of crystals

    International Nuclear Information System (INIS)

    Wan, Lingyu; Zhou, Yu; Liu, Liren; Sun, Jianfeng

    2013-01-01

    A free-space 2 × 4 90° optical hybrid with electro-optic modulation is presented. The hybrid principally consists of two pairs of electro-optic crystal plates coated with gold electrodes and a polarization analyzer. The optical hybrid uses the birefringence effect of a crystal to split and combine a signal beam and a local oscillator beam, uses the electro-optic effect to introduce a phase modulation and produce a phase shift, and outputs four-channel signal/local oscillator mixed beams whose phase difference can be adjusted continuously. A LiNbO 3 crystal is used to design and manufacture the space optical hybrid, and an experimental system is used to verify its performance. The results show that the output phase of the hybrid is continuously adjustable, enabling the hybrid to function perfectly as a 2 × 4 90° space optical hybrid under an appropriate electric field, and that the phase error can be compensated for by an electric field adjustment. (paper)

  9. 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)

  10. 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.

  11. 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.

  12. 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.

  13. Preliminary Sensorimotor and Cardiovascular Results from the Joint Russian and U.S. Pilot Field Test with Planning for the Full Field Test Beginning with the Year Long Intenational Space Station

    Science.gov (United States)

    Reschke, M. F.; Kozlovskaya, I. B.; Tomilovskaya, E. S.; Bloomberg, J. J.; Platts, S. H.; Rukavishnikov, I. V.; Fomina, E. V.; Stenger, M. B.; Lee, S. M. C.; Wood, S. J.; hide

    2014-01-01

    Ongoing collaborative research efforts between NASA's Neuroscience and Cardiovascular Laboratories, and the Institute of Biomedical Problems' (IBMP) Sensory-Motor and Countermeasures Laboratories have been measuring functional sensorimotor, cardiovascular and strength responses following bed rest, dry immersion, short duration (Space Shuttle) and long duration (Mir and International Space Station) space flights. While the unloading paradigms associated with dry immersion and bed rest does serve as acceptable flight analogs, testing of crew responses following the long duration flights previously has not been possible until a minimum of 24 hours after landing. As a result, it is not possible to estimate the nonlinear trend of the early (the full impact of the decrements associated with long duration flight. To overcome these limitations, both the Russian and U.S. sides have implemented testing at landing site. By joint agreement, this research effort has been identified as the functional Field Test (FT). For practical reasons the FT has been divided into two phases: the full FT and a preliminary pilot version (PFT) of the FT that is reduced in both length and scope. The primary goal of this research is to determine functional abilities in long duration space flight crews beginning as soon after landing as possible (one to three immediate follow-up measurements on the day of landing. This goal has both sensorimotor and cardiovascular elements, including evaluations of NASA's new anti-orthostatic compression garment and the Russian Kentavr garment. Functional sensorimotor measurements will include, but are not limited to, assessment of hand/eye coordination, ability to egress from a seated position, walk normally without falling, measurement of dynamic visual acuity, ability to discriminate different forces generated with both the hands and legs, recovery from a fall, a coordinated walk involving tandem heel-to-toe placement, and determination of postural ataxia while

  14. 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.

  15. High-speed polarized light microscopy for in situ, dynamic measurement of birefringence properties

    Science.gov (United States)

    Wu, Xianyu; Pankow, Mark; Shadow Huang, Hsiao-Ying; Peters, Kara

    2018-01-01

    A high-speed, quantitative polarized light microscopy (QPLM) instrument has been developed to monitor the optical slow axis spatial realignment during controlled medium to high strain rate experiments at acquisition rates up to 10 kHz. This high-speed QPLM instrument is implemented within a modified drop tower and demonstrated using polycarbonate specimens. By utilizing a rotating quarter wave plate and a high-speed camera, the minimum acquisition time to generate an alignment map of a birefringent specimen is 6.1 ms. A sequential analysis method allows the QPLM instrument to generate QPLM data at the high-speed camera imaging frequency 10 kHz. The obtained QPLM data is processed using a vector correlation technique to detect anomalous optical axis realignment and retardation changes throughout the loading event. The detected anomalous optical axis realignment is shown to be associated with crack initiation, propagation, and specimen failure in a dynamically loaded polycarbonate specimen. The work provides a foundation for detecting damage in biological tissues through local collagen fiber realignment and fracture during dynamic loading.

  16. Probing Stress-Induced Optical Birefringence of Glassy Polymers by Whispering Gallery Modes Light Localization.

    Science.gov (United States)

    Milenko, Karolina; Pissadakis, Stavros; Gkantzounis, Georgios; Aluculesei, Alina; Fytas, George

    2017-12-31

    An optical resonance method for the determination of the strain- and stress-optical coefficients of optically transparent polymers is presented and exemplified for monodisperse and bidisperse molecular weight polystyrene (PS). This method employs whispering gallery modes (WGMs) resonation inside a spheroid polymeric cavity, suspended on an optical fiber taper waist, which, in turn, is used for subjecting the polymeric resonator to controlled strain conditions. The wavelength shifts of equal order transverse electric and transverse magnetic polarization WGMs are measured, as well as their relative birefringence versus applied strain. For monodisperse PS microspheroids (2 and 50 kDa) the stress-optical coefficient is negative, contrary to the results for bulk PS in the glassy state indicating different phenyl group orientation of the PS monomer with respect to the strain direction. In the bidisperse (2 and 50 kDa) spheroid with a symmetric monomer composition, local structural irregularities are probably responsible for the observed coupling between WGMs. The method possesses metrological capabilities for probing the molecular orientation of polymer-based resonators.

  17. Performance tolerance analysis of birefringent fiber loop for semiconductor optical amplifier pattern effect suppression

    Science.gov (United States)

    Rizou, Zoe V.; Zoiros, Kyriakos E.; Hatziefremidis, Antonios; Connelly, Michael J.

    2015-05-01

    In this paper, we analyze the performance of the birefringent fiber loop (BFL) when the settings of the components that construct this module are not perfect. The BFL is employed for suppressing the pattern effect on directly amplified data in a semiconductor optical amplifier (SOA). The analysis is conducted by describing the non-optimum BFL transmission response using Jones matrix method. This allows to formulate a comprehensive model, which is validated by comparing it to the experiment. Then we investigate and specify how sensitive the BFL is to imperfections of its building components by assessing its performance against the output amplitude modulation, power penalty, and crosstalk. For each critical operating parameter, we derive the tolerance range within which these performance metrics are acceptable. The obtained results suggest that the BFL can efficiently mitigate the SOA pattern effect even if it is built from non-ideal components. This can be achieved provided that these components are designed according to their extracted operating conditions, which are practically satisfiable.

  18. 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.

  19. Circular birefringence/dichroism measurement of optical scattering samples using amplitude-modulation polarimetry

    Science.gov (United States)

    Liu, Wei-Chun; Lo, Yu-Lung; Phan, Quoc-Hung

    2018-03-01

    A method is proposed for extracting the circular birefringence (CB), circular dichroism (CD) and depolarization (Dep) properties of optical scattering samples using an amplitude-modulation polarimetry technique. The validity of the proposed method is demonstrated by extracting the CB property of pure glucose aqueous samples, the CB/Dep properties of glucose solutions containing 0.02% lipofundin particles, and the CD/Dep properties of chlorophyllin solutions containing suspended polystyrene microspheres. The results show that the proposed technique has the ability to detect pure glucose with a resolution of 66 mg/dL over a concentration range of 0-500 mg/dL. Moreover, the glucose concentration of the CB/Dep samples can be detected over the same range with a resolution of 168 mg/dL. Finally, the chlorophyllin concentration of the CD/Dep sample can be detected over the range of 0-200 μg/dL with a resolution of 6.5 × 10-5. In general, the results show that the proposed technique provides a reliable and accurate means of measuring the CB/CD properties of optical samples with scattering effects, and thus has significant potential for biological sensing applications.

  20. Low-birefringent and highly tough nanocellulose-reinforced cellulose triacetate.

    Science.gov (United States)

    Soeta, Hiroto; Fujisawa, Shuji; Saito, Tsuguyuki; Berglund, Lars; Isogai, Akira

    2015-05-27

    Improvement of the mechanical and thermal properties of cellulose triacetate (CTA) films is required without sacrificing their optical properties. Here, poly(ethylene glycol) (PEG)-grafted cellulose nanofibril/CTA nanocomposite films were fabricated by casting and drying methods. The cellulose nanofibrils were prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and amine-terminated PEG chains were grafted onto the surfaces of the TEMPO-oxidized cellulose nanofibrils (TOCNs) by ionic bonds. Because of the nanosize effect of TOCNs with a uniform width of ∼3 nm, the PEG-TOCN/CTA nanocomposite films had high transparency and low birefringence. The grafted PEG chains enhanced the filler-matrix interactions and crystallization of matrix CTA molecules, resulting in the Young's modulus and toughness of CTA film being significantly improved by PEG-grafted TOCN addition. The coefficient of thermal expansion of the original CTA film was mostly preserved even with the addition of PEG-grafted TOCNs. These results suggest that PEG-TOCNs are applicable to the reinforcement for transparent optical films.

  1. Research on the detection system of liquid concentration base on birefringence light transmission method

    Science.gov (United States)

    Li, Tianze; Zhang, Xia; Hou, Luan; Jiang, Chuan

    2010-10-01

    The characteristics of the beam transmitting in the optical fiber and the liquid medium are analyzed in this paper. On this basis, a new type of semiconductor optical position sensitive detector is used for a receiving device, a light transmission method of birefringence is presented,and a set of opto-electrical detection system which is applied to detect liquid concentration is designed. The system is mainly composed of semiconductor lasers,optical systems, Psd signal conditioning circuit, Single-chip System, A/D conversion circuit and display circuit. Through theoretical analysis and experimental simulations, the accuracy of this system has been verified. Some main factors affecting the test results are analyzed detailedly in this paper. The experiments show that the temperature drift and the light intensity have a very small impact on this system. The system has some advantages, such as the simple structure, high sensitivity, good stability, fast response time, high degree of automation, and so on. It also can achieve the real-time detection of liquid concentration conveniently and accurately. The system can be widely applied in chemical, food, pharmacy and many other industries. It has broad prospects of application.

  2. 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.

  3. POINT-BY-POINT INSCRIPTION OF FIBER BRAGG GRATINGS INTO BIREFRINGENT OPTICAL FIBER THROUGH PROTECTIVE ACRYLATE COATING BY TI:SA FEMTOSECOND LASER

    Directory of Open Access Journals (Sweden)

    S. V. Arkhipov,

    2016-05-01

    Full Text Available The paper deals withpoint-by-point inscriptionof fiber Bragg gratings by the 800 nm Ti:Sa femtosecond laser pulses into a unique birefringent fiber with elliptical stress cladding of home manufacture. The proposed inscriptionmethod has advantages over the conventional phase mask method. The possibility to create complex grating structures and relatively high transparency of acrylate coating to the Ti:Sa femtosecond laser radiation of 800 nm gives the possibility for inscriptionof phase shifting gratings, chirped grating and superstructures without stripping the fiber. Also, this method makes it possible to inscribethese diffractive structures with and without co-doping of GeO2 in the fiber core. Achieved reflectance was 10%. The microscopic image of the diffractive structure in the fiber core is presented. The grating of 1.07 µm is realized by pulling the fiber with constant speed while the laser pulses are applied with a repetition frequency of 1 kHz. The results are usable in the sphere of creation of different fiber optic sensitive elements based on Bragg gratings.

  4. High-birefringence photonic crystal fiber polarization filter with gold-coated and liquid-filled air holes based on surface plasmon resonance

    Science.gov (United States)

    Lou, Junbo; Li, Shuguang; Cheng, Tonglei; Yan, Xin; Zhang, Xuenan

    2018-01-01

    A high-birefringence photonic crystal fiber polarization filter is proposed. The coupling theory is used to explain full and incomplete couplings. The resonance point can be adjusted to the communication band by optimizing the fiber structure parameters. Numerical simulation results indicate that the resonance strength can reach 924.96 and 710.28 dB.cm-1 at the communication wavelength of 1.31 and 1.55 μm in x- and y-polarized directions, respectively. By filling liquid analyte, the confinement loss can reach 804.52 dB.cm-1 at the wavelength of 1.55 μm. Furthermore, when the fiber length of L equals 500 μm, the peak value of the cross talk (CT) can reach 389.15 and -280.52 dB, respectively. When the length of the fiber L equals 200 μm, the bandwidth of the CT better than 20 dB is up to 120 nm at the wavelength of 1.31 μm, and the bandwidth of the CT<-20 dB is up to 140 nm at the wavelength of 1.55 μm. These properties make it a good candidate for designing types of polarization filter devices.

  5. 3D full-field quantification of cell-induced large deformations in fibrillar biomaterials by combining non-rigid image registration with label-free second harmonic generation.

    Science.gov (United States)

    Jorge-Peñas, Alvaro; Bové, Hannelore; Sanen, Kathleen; Vaeyens, Marie-Mo; Steuwe, Christian; Roeffaers, Maarten; Ameloot, Marcel; Van Oosterwyck, Hans

    2017-08-01

    To advance our current understanding of cell-matrix mechanics and its importance for biomaterials development, advanced three-dimensional (3D) measurement techniques are necessary. Cell-induced deformations of the surrounding matrix are commonly derived from the displacement of embedded fiducial markers, as part of traction force microscopy (TFM) procedures. However, these fluorescent markers may alter the mechanical properties of the matrix or can be taken up by the embedded cells, and therefore influence cellular behavior and fate. In addition, the currently developed methods for calculating cell-induced deformations are generally limited to relatively small deformations, with displacement magnitudes and strains typically of the order of a few microns and less than 10% respectively. Yet, large, complex deformation fields can be expected from cells exerting tractions in fibrillar biomaterials, like collagen. To circumvent these hurdles, we present a technique for the 3D full-field quantification of large cell-generated deformations in collagen, without the need of fiducial markers. We applied non-rigid, Free Form Deformation (FFD)-based image registration to compute full-field displacements induced by MRC-5 human lung fibroblasts in a collagen type I hydrogel by solely relying on second harmonic generation (SHG) from the collagen fibrils. By executing comparative experiments, we show that comparable displacement fields can be derived from both fibrils and fluorescent beads. SHG-based fibril imaging can circumvent all described disadvantages of using fiducial markers. This approach allows measuring 3D full-field deformations under large displacement (of the order of 10 μm) and strain regimes (up to 40%). As such, it holds great promise for the study of large cell-induced deformations as an inherent component of cell-biomaterial interactions and cell-mediated biomaterial remodeling. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Prudente, Alessandro; Fávaro, Wágner José; Latuf, Paulo; Riccetto, Cássio Luis Zanettini

    2016-01-01

    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. PMID:27286125

  7. Three-band, 1.9-μm axial resolution full-field optical coherence microscopy over a 530-1700 nm wavelength range using a single camera

    OpenAIRE

    Federici, Antoine; Dubois, Arnaud

    2014-01-01

    International audience; Full-field optical coherence microscopy is an established optical technology based on low-coherence interference microscopy for high-resolution imaging of semitransparent samples. In this Letter, we demonstrate an extension of the technique using a visible to short-wavelength infrared camera and a halogen lamp to image in three distinct bands centered at 635, 870, and 1170 nm. Reflective microscope objectives are employed to minimize chromatic aberrations of the imagin...

  8. 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.

  9. A compact fiber sensor based on the high birefringence polarization maintaining fiber for simultaneous strain and temperature measurement

    Science.gov (United States)

    Li, Kang; Cao, Zhigang; Zhang, Guosheng; Wang, Jian; Lin, Jiping; Yu, Benli

    2017-10-01

    A compact high birefringence polarization maintaining fiber (PMF) sensor for simultaneous strain and temperature measurement is proposed. This sensor is a modal interferometer (MI) sensor which is composed of a segment of high birefringence polarization maintaining fiber. One side of the fiber is spliced to the pigtail of a polarization beam splitter (PBS) with core-offset and axes alignment, the other end is spliced to the standard single-mode fiber (SMF) with core alignment and forms a fiber bubble. In experiments, an optical switch and the PBS are used to generate two orthogonal linear polarized lights. When the two orthogonal linear polarized lights enter the sensing fiber respectively, two different interference spectra will be achieved and own different response to the strain and temperature. Using these properties, the sensor realizes the simultaneous strain and temperature measurement. For 0.01 nm wavelength resolution, the strain and temperature resolution of the sensor are 10 uɛ and 0.285°C, respectively.

  10. 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

  11. Radiation exposure in full-field digital mammography with a flat-panel X-ray detector based on amorphous silicon in comparison with conventional screen-film mammography

    International Nuclear Information System (INIS)

    Hermann, K.P.; Obenauer, S.; Grabbe, E.

    2000-01-01

    Comparison of radiation exposure between a digital amorphous silicon and a screen-film based mammography system. Evaluation of a possible potential of full-field digital mammography in order to decrease the radiation dose. Methods: The average glandular dose for phantom thicknesses from 30 to 60 mm was calculated from experimentally determined entrance surface air kerma for a digital and a conventional mammography system. The effect of reducing the detector dose and of changing the radiation quality on radiation exposure and on image quality were investigated. Results: By using the delivered settings of the automatic exposure control (AEC) devices, both mammographic systems needed nearly the same doses. Regulations and guidelines on radiation doses were complied. With the digital system, a reduction of radiation exposure of up to 40% by using a higher radiation quality and decreasing slightly the detector dose without loss of diagnostic image quality, might be possible. Conclusion: The potential of full-field digital mammography for radiation dose reduction, as shown in the present phantom study, needs however, a careful examination under clinical conditions. (orig.) [de

  12. Controlled Terahertz Birefringence in Stretched Poly(lactic acid) Films Investigated by Terahertz Time-Domain Spectroscopy and Wide-Angle X-ray Scattering.

    Science.gov (United States)

    Iwasaki, Hotsumi; Nakamura, Madoka; Komatsubara, Nozomu; Okano, Makoto; Nakasako, Masayoshi; Sato, Harumi; Watanabe, Shinichi

    2017-07-20

    We report a correlation between the dielectric property and structure of stretched poly(lactic acid) (PLA) films, revealed by polarization-sensitive terahertz time-domain spectroscopy and two-dimensional (2D) wide-angle X-ray scattering (WAXS). The experiments evidence that the dielectric function of the PLA film becomes more anisotropic with increasing draw ratio (DR). This behavior is explained by a classical Lorentz oscillator model assuming polarization-dependent absorption. The birefringence can be systematically altered from 0 to 0.13 by controlling DR. The combination of terahertz spectroscopy and 2D WAXS measurement reveals a clear correlation between the birefringence in the terahertz frequency domain and the degree of orientation of the PLA molecular chains. These findings imply that the birefringence is a result of the orientation of the PLA chains with anisotropic macromolecular vibration modes. Because of a good controllability of the birefringence, polymer-based materials will provide an attractive materials system for phase retarders in the terahertz frequency range.

  13. A QM/MM and QM/QM/MM study of Kerr, Cotton-Mouton and Jones linear birefringences in liquid acetonitrile

    DEFF Research Database (Denmark)

    Fahleson, Tobias; Olsen, Jógvan Magnus Haugaard; Norman, Patrick

    2018-01-01

    QM/MM and QM/QM/MM protocols are applied to the ab initio study of the three linear birefringences Kerr, Cotton-Mouton, and Jones, as shown by acetonitrile in the gas and pure liquid phases. The relevant first-order properties as well as linear, quadratic, and cubic frequency-dependent response...

  14. Determination of the photoinduced birefringence and of the refractive index by Brewster method of epoxy resin doped with CdS

    Science.gov (United States)

    Silveira, J. B.; Reynoso, V. C. S.; Aquino, H. A.; Carvalho, C. L.

    2012-09-01

    This work describes the synthesis of polymeric composites based on epoxy resin doped with different concentrations of cadmium sulfide (CdS). We studied the photoinduced birefringence and the refractive index by Brewster method as a function of the CdS concentration. UV-Vis spectroscopy was used to determine the absorption bands of the samples. An experimental arrangement to ascertain the photoinduced birefringence used a writing LASER (ion Ar+ of λ = 457 nm) and a reading LASER (He-Ne of λ = 632.8 nm). The results were quantified using the theoretical model purposed by Debye, where it was observed that the pure epoxy resin presented photoinduced birefringence, which increased with the addition of the CdS. Therefore, it was verified that the variation of the power of the writing LASER directly contributes to the amount of photoinduced birefringence. In addition, the behavior of the refractive index of the composite as a function of the addition of CdS was verified by the Brewster angle technique to provide a wavelength of 650 nm using a radiation source with a monochromator. We observed a linear increase in the refractive index with the addition of CdS.

  15. Evolution of full stokes parameters in polarized radiative transfer of electron cyclotron waves on LHD

    Energy Technology Data Exchange (ETDEWEB)

    Idei, H.; Kubo, S.; Shimozuma, T.; Tsumori, K.; Watari, T.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Takita, Y.; Yoshimura, Y.; Ohkubo, K.; Sakakibara, S.; Narihara, K.; Yamada, I.; Tanaka, K.; Morisaki, T.; Watanabe, K. Y.; Nakanishi, H.; Ohdachi, S.; Emoto, M.; Matsuoka, K.; Motojima, O.; Fujiwara, M. [LHD Experimental Group, National Institute for Fusion Science, Toki, 509-5292 (Japan); Notake, T. [Nagoya University, Faculty of Engineering, Nagoya, 464-8603 (Japan)

    2003-07-01

    To study polarized radiative transfer of electron cyclotron waves, a general equation of polarization evolution that includes the effects of both birefringence and dichroism is dealt with. Full Stokes parameters are used to describe the polarization state and the absorption rate in the equation. The evolution equation on polarization state is able to treat general cases in which two polarization states of Eigenmodes are not necessary to be orthogonal. Using this equation, a single absorption rate in second harmonic electron cyclotron heating is investigated on the Large Helical Device. (authors)

  16. Change in Knowledge of Kindergarten Employees Participating in the Course “Diet full of life” in the Field of Children’s Nutrition, as Assessed by Generalized Estimating Equations

    Directory of Open Access Journals (Sweden)

    Zalewska Magdalena

    2016-12-01

    Full Text Available Nutrition is one of the most important environmental factors affecting the physical development and health of children. Education in this area and the development of proper eating habits are priorities. A prerequisite for the proper nutrition of preschool children is knowledge of proper nutrition of people working there. The aim of this study was an evaluation of the knowledge of kindergarten employees participating in the course “Diet full of life – courses in the field of children’s nutrition”. The study included 90 employees of nurseries and kindergartens, participants of the course in the field of children’s nutrition. The research tool was an original questionnaire. Study I (pre-test was performed before the beginning of the course, while study II (post-test was performed after its completion. Generalized Linear Models with a Generalized Estimating Equations extension was used to estimate the impact of the number of covariates on knowledge of course participants, taking into consideration the correlation between before- and after-course results. An increase in the knowledge of the participants of the investigated course on children’s nutritional standards was significant and reached 2.053 points on average. No relationship between age, job position, and knowledge level was determined. In the area of principles of proper nutrition for children, older participants had a lower level of knowledge compared to younger ones, and participants with higher education showed a significantly higher knowledge increase as compared to those with vocational education. A significant knowledge increase in the field of dietary behaviors of children was obtained during the course by all examined women, 1.6 points on average (p < 0.001. Younger participants obtained significantly more knowledge from the course than older ones (p < 0.001. Thus, it can be concluded that realization of the course entitled “Diet full of life” specifically relating to

  17. Stimulated Brillouin scattering in highly birefringent multimode tapered chalcogenide photonic crystal fiber for distributed optical sensors (Retraction Notice)

    Science.gov (United States)

    Baili, Amira; Cherif, Rim; Zghal, Mourad

    2016-09-01

    This paper, originally published on September 15, 2016, was retracted from the SPIE Digital Library on October 5, 2016, due to a high degree of similarity between specific portions of the text of the paper to the following publications: J. Tchahame, J. Beugnot, A. Kudlinski, and T. Sylvestre, "Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber," Opt. Lett. 40, 4281-4284 (2015). doi: 10.1364/OL.40.004281 W. W. Ke, X. J. Wang and X. Tang, "Stimulated Brillouin Scattering Model in Multi-Mode Fiber Lasers," in IEEE Journal of Selected Topics in Quantum Electronics, vol. 20, no. 5, pp. 305-314, Sept.-Oct. 2014. doi: 10.1109/JSTQE.2014.2303256.

  18. Coherent Pair Production by Photons in the 20-170 GeV Energy Range Incident on Crystals and Birefringence

    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

    The cross section for coherent pair production by linearly polarised photons in the 20-170 GeV energy range was measured for photon aligned incidence on ultra-high quality diamond and germanium crystals. The theoretical description of coherent bremsstrahlung and coherent pair production phenomena is an area of active theoretical debate and development. However, under our experimental conditions, the theory predicted the combined cross section and polarisation experimental observables very well indeed. In macroscopic terms, our experiment measured a birefringence effect in pair production in a crystal. This study of this effect also constituted a measurement of the energy dependent linear polarisation of photons produced by coherent bremsstrahlung in aligned crystals. New technologies for manipulating high energy photon beams can be realised based on an improved understanding of QED phenomena at these energies. In particular, this experiment demonstrates an efficient new polarimetry technique. The pair product...

  19. Entanglement networks of 1,2-polybutadiene crosslinked in states of strain. VII. Stress-birefringence relations. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kan, H.C.; Carpenter, R.L.; Ferry, J.D.

    1979-11-01

    Crosslinks are introduced by ..gamma.. irradiation into 1,2-polybutadiene while strained in uniaxial extension near T/sub g/ with stretch ratio lambda/sub 0/, thereby trapping a proportion of the entanglements originally present. The stress at any subsequent strain lambda is accurately given by the sum sigma/sub N/ + sigma/sub x/, where sigma/sub N/ is the stress contributed by a trapped entanglement network with lambda = 1 as reference and a Mooney-Rivlin stress-strain relation, and sigma/sub x/ is that contributed by a crosslink network with lambda = lambda/sub 0/ as reference and neo-Hookean stress-strain relation. The birefringence is accurately given as ..delta..n = C/sub N/sigma/sub N/ + C/sub x/sigma/sub x/, where the C's are the respective stress-optical coefficients. From measurements at lambda = lambda/sub 0/ where sigma/sub x/ = 0, C/sub N/ can be determined separately. For polymer with 88% 1,2-microstructure, C/sub N/ and C/sub x/ are nearly equal and independent of irradiation dose, though strongly dependent on temperature. For polymer with (95-96)% 1,2, C/sub N/ and C/sub x/ are different (even opposite in sign) and dependent on dose. This behavior is associated with a side reaction of cyclization by the ..gamma.. irradiation, which is inhibited by the 1,4 moiety in the polymer with lesser 1,2 content. It is responsible for residual birefringence in the state of ease (lambda = lambda/sub s/) where sigma/sub N/ = -sigma/sub x/ and the stress is zero.

  20. Comparison of the Detection Rate of Simulated Microcalcifications in Full-Field Digital Mammography, Digital Breast Tomosynthesis, and Synthetically Reconstructed 2-Dimensional Images Performed With 2 Different Digital X-ray Mammography Systems.

    Science.gov (United States)

    Peters, Sabine; Hellmich, Martin; Stork, Alexander; Kemper, Jörn; Grinstein, Olga; Püsken, Michael; Stahlhut, Leandra; Kinner, Sonja; Maintz, David; Krug, Kathrin Barbara

    2017-04-01

    The aim of this study was to compare the microcalcification detectability in an anthropomorphic phantom model regarding number, size, and shape in full-field digital mammography (FFDM), synthetically reconstructed 2-dimensional (Synthetic-2D) images, and digital breast tomosynthesis (DBT) performed with 2 different x-ray mammography systems. Simulated microcalcifications of different numbers (0 to >39), sizes (diameter, 100-800 μm), and shapes (round vs heterogeneous) were scattered by random distribution on 50 film phantoms each divided in 4 quadrants. The FFDM and DBT x-rays were taken from each of these 50 films with both x-ray mammography systems (SenoClaire; GE Healthcare, Selenia Dimensions, Hologic) using an anthropomorphic scattering body and automatic exposure control. The resulting exposure factors were similar to a clinical setting. The synthetically reconstructed 2D images were generated automatically on both systems. All FFDM, Synthetic-2D, and DBT images were interpreted in randomized order and independently of each other by 6 radiologists using a structured questionnaire. The number categories of simulated microcalcifications were correctly evaluated in 55.3% of instances (quadrant by reader) in FFDM, 50.9% in the Synthetic-2D views, and 59.5% in DBT, summarized for 200 quadrants per reader for each Device A and B, respectively. Full-field digital mammography was superior to Synthetic-2D (mean difference, 4%; 95% confidence interval [CI], 2%-7%; P mammography was superior to synthetically reconstructed 2-dimensional images in the detection of simulated microcalcifications. In view of these results, it is questionable whether Synthetic-2D images can replace FFDM in clinical examinations at the present time. Further investigations are needed to assess the clinical impact of the in vitro results.

  1. download full text

    African Journals Online (AJOL)

    The fields of ethical and value-based leadership have gained momentum over the last three decades. Many scholars have made major contributions in this field of scientific inquiry. (Burns 1978, O'Toole 1996, Dean 2008). Ethical leadership practice refers to how people conduct their affairs as moral agents at individual and ...

  2. Full-Field Calcium K-Edge X-ray Absorption Near-Edge Structure Spectroscopy on Cortical Bone at the Micron-Scale: Polarization Effects Reveal Mineral Orientation.

    Science.gov (United States)

    Hesse, Bernhard; Salome, Murielle; Castillo-Michel, Hiram; Cotte, Marine; Fayard, Barbara; Sahle, Christoph J; De Nolf, Wout; Hradilova, Jana; Masic, Admir; Kanngießer, Birgit; Bohner, Marc; Varga, Peter; Raum, Kay; Schrof, Susanne

    2016-04-05

    Here, we show results on X-ray absorption near edge structure spectroscopy in both transmission and X-ray fluorescence full-field mode (FF-XANES) at the calcium K-edge on human bone tissue in healthy and diseased conditions and for different tissue maturation stages. We observe that the dominating spectral differences originating from different tissue regions, which are well pronounced in the white line and postedge structures are associated with polarization effects. These polarization effects dominate the spectral variance and must be well understood and modeled before analyzing the very subtle spectral variations related to the bone tissue variations itself. However, these modulations in the fine structure of the spectra can potentially be of high interest to quantify orientations of the apatite crystals in highly structured tissue matrices such as bone. Due to the extremely short wavelengths of X-rays, FF-XANES overcomes the limited spatial resolution of other optical and spectroscopic techniques exploiting visible light. Since the field of view in FF-XANES is rather large the acquisition times for analyzing the same region are short compared to, for example, X-ray diffraction techniques. Our results on the angular absorption dependence were verified by both site-matched polarized Raman spectroscopy, which has been shown to be sensitive to the orientation of bone building blocks and by mathematical simulations of the angular absorbance dependence. As an outlook we further demonstrate the polarization based assessment of calcium-containing crystal orientation and specification of calcium in a beta-tricalcium phosphate (β-Ca3(PO4)2 scaffold implanted into ovine bone. Regarding the use of XANES to assess chemical properties of Ca in human bone tissue our data suggest that neither the anatomical site (tibia vs jaw) nor pathology (healthy vs necrotic jaw bone tissue) affected the averaged spectral shape of the XANES spectra.

  3. Full closure strategic analysis.

    Science.gov (United States)

    2014-07-01

    The full closure strategic analysis was conducted to create a decision process whereby full roadway : closures for construction and maintenance activities can be evaluated and approved or denied by CDOT : Traffic personnel. The study reviewed current...

  4. Existence of an isotropic point and birefringence dispersion study in (C2H5NH3)2CuCl4 crystal near its thermochromic phase transition

    Science.gov (United States)

    Fernandez, J.; Gomez Cuevas, A.; Arriandiaga, M. A.; Socias, C.; Tello, M. J.

    1985-04-01

    The anomalous optical dispersion and the existence of an isotropic point in the organic-inorganic double-halide (C2H5NH3)2CuCl4 crystal (in short EACuC) around its thermochromic low-temperature phase transition were investigated by means of birefringence, thermal expansion, and calorimetric measurements as well as by direct conoscopic and orthoscopic observations under polarized light. The birefringence dispersion data are analyzed using a simple two-oscillator model based on the optical band structure of EACuC. The model adjustable parameters are related with the oscillator strength and average positions, respectively. The thermal behavior of the involved parameters is compatible with the existence of the isotropic point below the thermochromic phase transition. These results, together with the optical extinction measurements and the domain pattern observations, suggest a complicated structural phase-transition sequence which is also discussed.

  5. 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.

  6. Detecting central fixation by means of artificial neural networks in a pediatric vision screener using retinal birefringence scanning.

    Science.gov (United States)

    Gramatikov, Boris I

    2017-04-27

    Reliable detection of central fixation and eye alignment is essential in the diagnosis of amblyopia ("lazy eye"), which can lead to blindness. Our lab has developed and reported earlier a pediatric vision screener that performs scanning of the retina around the fovea and analyzes changes in the polarization state of light as the scan progresses. Depending on the direction of gaze and the instrument design, the screener produces several signal frequencies that can be utilized in the detection of central fixation. The objective of this study was to compare artificial neural networks with classical statistical methods, with respect to their ability to detect central fixation reliably. A classical feedforward, pattern recognition, two-layer neural network architecture was used, consisting of one hidden layer and one output layer. The network has four inputs, representing normalized spectral powers at four signal frequencies generated during retinal birefringence scanning. The hidden layer contains four neurons. The output suggests presence or absence of central fixation. Backpropagation was used to train the network, using the gradient descent algorithm and the cross-entropy error as the performance function. The network was trained, validated and tested on a set of controlled calibration data obtained from 600 measurements from ten eyes in a previous study, and was additionally tested on a clinical set of 78 eyes, independently diagnosed by an ophthalmologist. In the first part of this study, a neural network was designed around the calibration set. With a proper architecture and training, the network provided performance that was comparable to classical statistical methods, allowing perfect separation between the central and paracentral fixation data, with both the sensitivity and the specificity of the instrument being 100%. In the second part of the study, the neural network was applied to the clinical data. It allowed reliable separation between normal subjects

  7. Time to return to full training is delayed and recurrence rate is higher in intratendinous ('c') acute hamstring injury in elite track and field athletes: clinical application of the British Athletics Muscle Injury Classification.

    Science.gov (United States)

    Pollock, Noel; Patel, Anish; Chakraverty, Julian; Suokas, Anu; James, Stephen L J; Chakraverty, Robin

    2016-03-01

    The British Athletics Muscle Injury Classification describes acute muscle injuries and their anatomical site within muscle based on MRI parameters of injury extent. It grades injuries from 0 to 4 and classifies location based on a myofascial (a), musculotendinous (b) or intratendinous (c) description. This is a retrospective cohort study that assessed time to return to full training (TRFT) and injury recurrence in the different British Athletics classifications for hamstring injuries sustained by elite track and field (T&F) athletes over a 4-year period. The electronic medical records (EMRs) of 230 elite British T&F athletes were reviewed. Athletes who sustained an acute hamstring injury, with MRI investigation within 7 days of injury, were included. MRI were graded by two musculoskeletal radiologists using the British Athletics Muscle Injury Classification. The EMRs were reviewed by 2 sports physicians, blinded to the new classification; TRFT and injury recurrence were recorded. There were 65 hamstring injuries in 44 athletes (24±4.4 years; 28 male, 16 female). TRFT differed among grades (pinjuries and 'c' injuries took significantly longer and grade 0 injuries took less TRFT. There were 12 re-injuries; the injury recurrence rate was significantly higher in intratendinous (c) injuries (pinjury rate between number grades 1-3, hamstring muscle affected, location (proximal vs central vs distal), age or sex. This study describes the clinical application of the British Athletics Muscle Injury Classification. Different categories of hamstring injuries had different TRFT and recurrence rate. Hamstring injuries that extend into the tendon ('c') are more prone to re-injury and delay TRFT. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  8. Toward full spectrum speciation of silver nanoparticles and ionic silver by on-line coupling of hollow fiber flow field-flow fractionation and minicolumn concentration with multiple detectors.

    Science.gov (United States)

    Tan, Zhi-Qiang; Liu, Jing-Fu; Guo, Xiao-Ru; Yin, Yong-Guang; Byeon, Seul Kee; Moon, Myeong Hee; Jiang, Gui-Bin

    2015-08-18

    The intertransformation of silver nanoparticles (AgNPs) and ionic silver (Ag(I)) in the environment determines their transport, uptake, and toxicity, demanding methods to simultaneously separate and quantify AgNPs and Ag(I). For the first time, hollow fiber flow field-flow fractionation (HF5) and minicolumn concentration were on-line coupled together with multiple detectors (including UV-vis spectrometry, dynamic light scattering, and inductively coupled plasma mass spectrometry) for full spectrum separation, characterization, and quantification of various Ag(I) species (i.e., free Ag(I), weak and strong Ag(I) complexes) and differently sized AgNPs. While HF5 was employed for filtration and fractionation of AgNPs (>2 nm), the minicolumn packed with Amberlite IR120 resin functioned to trap free Ag(I) or weak Ag(I) complexes coming from the radial flow of HF5 together with the strong Ag(I) complexes and tiny AgNPs (90% of tiny AgNPs to free Ag(I) and trapped in the minicolumn. The excellent performance was verified by the good agreement of the characterization results of AgNPs determined by this method with that by transmission electron microscopy, and the satisfactory recoveries (70.7-108%) for seven Ag species, including Ag(I), the adduct of Ag(I) and cysteine, and five AgNPs with nominal diameters of 1.4 nm, 10 nm, 20 nm, 40 nm, and 60 nm in surface water samples.

  9. ROOT ANATOMICAL PLASTICITY IN RESPONSE TO SALT STRESS UNDER REAL AND FULL-SEASON FIELD CONDITIONS AND DETERMINATION OF NEW ANATOMIC SELECTION CHARACTERS FOR BREEDING SALT-RESISTANT RICE (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Mehmet AYBEKE

    2016-12-01

    Full Text Available Specific understanding of root anatomy plasticity under salt stress is lacking and requires creation of efficient screening techniques for stress condition s. To fill this gap, this study aimed to determine the anatomical plasticity in root chracteristics of 31 different rice cultivars (from ‘Best’ to ‘Low’ yielding grown under real field conditions (saline and non-saline from planting to harvesting and to reveal detailed root anatomical parameters that can be used to select and breed salt-tolerant rice. Anatomical and histochemical features of all cultivars and thin structures of the apoplastic barriers were investigated. The amount of silica (Si, 35 different anatomical characteristics, anatomical plasticity characteristics, plasticity rates, plasticity trends and changes and strategies of each group under saline and non-saline conditions were compared. The results showed that protective anatomical characters improved/remained equal to, and worsened/remained equal to those of the controls, in the ‘Best’ and other groups, respectively, from non-saline to saline conditions. Anatomical plasticity is essentially directly related to apoplastic barrier features. High genotypic variation was observed in root anatomy in all cultivars, but foremost traits were as follows: (1 cell size, (2 Si presence, (3 Si accumulation shape, (4 Si distribution towards root stele, (5 xylem arch features, (6 lignification-suberization properties in apoplastic barriers and their degrees, (7 presence/absence of idioblast cells filled with gummic and phenolic substances and (8 moderate anatomical plasticity. Cultivars with the most stabile anatomy under saline and non-saline conditions should be used to select and breed salt-resistant rice.

  10. Modeling Interferometric Structures with Birefringent Elements: A Linear Vector-Space Formalism

    Science.gov (United States)

    2013-11-12

    the input field from the ideal phase-matched condition . V APPLICATION Generalizing earlier work Earlier work[7] introduced a formalism using 4× 4...The carets in the equations above signify that the scalar matrix elements are to be linked to their respective time-delayed field operands . Once they...ψ〉 = cos θ2 e −j(φ̄+φ/2). Generalization to operators with overall phase Operators which preserve the norm of the vector operands are unitary, so that

  11. The Full Inclusion Movement.

    Science.gov (United States)

    Machado, Rodney E.; And Others

    1996-01-01

    Overviews background of the movement toward full inclusion of special education students into regular classrooms, including legal issues and successful educational practices. Suggests that full inclusion does not benefit all students and that inclusion should be one of several alternatives to meeting students' educational needs. Of approximately…

  12. A no-moving-parts sensor for the detection of eye fixation using polarised light and retinal birefringence information.

    Science.gov (United States)

    Gramatikov, Boris I; Guyton, David L

    2017-05-01

    Polarised near-infra-red light is reflected from the foveal area in a detectable bow-tie pattern of polarisation states, offering the opportunity for eye tracking. A coaxial optical transducer was developed, consisting of a laser diode, a polariser, a filter, and a photodetector. Several such transducers may be used to interrogate different spots on the retina, thus eliminating the requirement for scanning systems with moving parts. To test the signal quality obtainable, using just one transducer, a test subject was asked to fixate successively on twelve targets located on a circle around the transducer, to simulate the retina's being interrogated by twelve sensors placed on a 3 0 diameter circle surrounding the projection of the fovea. The resulting signal is close to the "ideal" sine wave that would have been recorded from a propeller-type birefringence pattern from a human fovea. The transducer can be used in the detection of fixation for medical and other purposes. It does not require calibration, strict restrictions on head position, or head-mounted appliances.

  13. 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.

  14. Adjustment errors of sunstones in the first step of sky-polarimetric Viking navigation: studies with dichroic cordierite/ tourmaline and birefringent calcite crystals.

    Science.gov (United States)

    Száz, Dénes; Farkas, Alexandra; Blahó, Miklós; Barta, András; Egri, Ádám; Kretzer, Balázs; Hegedüs, Tibor; Jäger, Zoltán; Horváth, Gábor

    2016-01-01

    According to an old but still unproven theory, Viking navigators analysed the skylight polarization with dichroic cordierite or tourmaline, or birefringent calcite sunstones in cloudy/foggy weather. Combining these sunstones with their sun-dial, they could determine the position of the occluded sun, from which the geographical northern direction could be guessed. In psychophysical laboratory experiments, we studied the accuracy of the first step of this sky-polarimetric Viking navigation. We measured the adjustment error e of rotatable cordierite, tourmaline and calcite crystals when the task was to determine the direction of polarization of white light as a function of the degree of linear polarization p. From the obtained error functions e(p), the thresholds p* above which the first step can still function (i.e. when the intensity change seen through the rotating analyser can be sensed) were derived. Cordierite is about twice as reliable as tourmaline. Calcite sunstones have smaller adjustment errors if the navigator looks for that orientation of the crystal where the intensity difference between the two spots seen in the crystal is maximal, rather than minimal. For higher p (greater than p crit) of incident light, the adjustment errors of calcite are larger than those of the dichroic cordierite (p crit=20%) and tourmaline (p crit=45%), while for lower p (less than p crit) calcite usually has lower adjustment errors than dichroic sunstones. We showed that real calcite crystals are not as ideal sunstones as it was believed earlier, because they usually contain scratches, impurities and crystal defects which increase considerably their adjustment errors. Thus, cordierite and tourmaline can also be at least as good sunstones as calcite. Using the psychophysical e(p) functions and the patterns of the degree of skylight polarization measured by full-sky imaging polarimetry, we computed how accurately the northern direction can be determined with the use of the Viking

  15. Full Service Leasing

    OpenAIRE

    Richter, Ján

    2009-01-01

    Aim of this master thesis is to describe the service of Full Service Leasing, as a modern form of financing and management of assets, primarily automobile fleet. Description of full service leasing is designed as a comprehensive and complete guide to support reader's position when deciding to finance and manage a fleet by this service. Whether the reader is an entrepreneur, CFO, fleet manager, new employee of leasing company, or anyone who is interested in this service, this master thesis wil...

  16. full on riot

    Directory of Open Access Journals (Sweden)

    Moses Iten

    2005-08-01

    Full Text Available “hey moses full on riot in lawson st the station’s on fire! been going since 4. molotov and more. full on,” reads an SMS message received on the backseat of a Tasmanian bus. What follows is a journey through the landscape of a Gunavidji, whose brothers have all gone to the land of the dead; metallic scraping in the glass cases of the Hobart Museum; a Palestinian woman giving up on her people; land-snails exposing cultural inaccuracies; photographing Australia’s war zone; entering the St Peter’s Basilica of Rome with bulldozers - all in the name of preparing to interview prominent Israeli writer Etgar Keret.

  17. Compressive full waveform lidar

    Science.gov (United States)

    Yang, Weiyi; Ke, Jun

    2017-05-01

    To avoid high bandwidth detector, fast speed A/D converter, and large size memory disk, a compressive full waveform LIDAR system, which uses a temporally modulated laser instead of a pulsed laser, is studied in this paper. Full waveform data from NEON (National Ecological Observatory Network) are used. Random binary patterns are used to modulate the source. To achieve 0.15 m ranging resolution, a 100 MSPS A/D converter is assumed to make measurements. SPIRAL algorithm with canonical basis is employed when Poisson noise is considered in the low illuminated condition.

  18. Full page insight

    DEFF Research Database (Denmark)

    Cortsen, Rikke Platz

    2014-01-01

    Alan Moore and his collaborating artists often manipulate time and space by drawing upon the formal elements of comics and making alternative constellations. This article looks at an element that is used frequently in comics of all kinds – the full page – and discusses how it helps shape spatio-t...

  19. Full page fax print

    Indian Academy of Sciences (India)

    user

    different classes, alkaloids, terpenes, oxygen heterocycles and other systems. It is impossible to do full justice to his work and this article provides only a selection ...... India is home to bounteous varieties of plants. However, very few of them have been studied, a vast majority being untouched. The scope for research in this ...

  20. Full Length Research Article

    African Journals Online (AJOL)

    Administrator

    Out of the 320 male sheep examined, 87(27.2%) were infected, while 9(19.1%) of the 47 females examined were infected (Table 2). Infection varied from one abattoir to another. Age related distribution of P. cervi is shown in Table 3. Out of 356 adult sheep (>2yrs) examined, 35. Full Length Research Article. 12 ...