WorldWideScience

Sample records for dispersed interferometry edi

  1. EDI.

    Bluh, Pamela; And Others

    1996-01-01

    This special section on EDI (Electronic Data Interchange) in libraries includes eight articles that discuss experiences in libraries in the United Kingdom, EDI and the acquisitions process in Europe, a Canadian viewpoint, the ILS (Integrated Library Systems) vendor and EDI, public libraries, and EDI in the information services industry. (LRW)

  2. Noise Studies of Externally Dispersed Interferometry for Doppler Velocimetry

    Erskine, D J; Edelstein, J; Lloyd, J; Muirhead, P

    2006-01-01

    Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. Both regular and high-frequency spectral components can be recovered from the data--the moire component carries additional information that increases the signal to noise for velocimetry and spectroscopy. Here we present simulations and theoretical studies of the photon limited Doppler velocity noise in an EDI. We used a model spectrum of a 1600K temperature star. For several rotational blurring velocities 0, 7.5, 15 and 25 km/s we calculated the dimensionless Doppler quality index (Q) versus wavenumber v. This is the normalized RMS of the derivative of the spectrum and is proportional to the photon-limited Doppler signal to noise ratio

  3. Chromatic dispersion effects in ultra-low coherence interferometry

    Lychagov, V V; Ryabukho, V P [N.G.Chernyshevsky Saratov State University (Russian Federation)

    2015-06-30

    We consider the properties of an interference signal shift from zero-path-difference position in the presence of an uncompensated dispersive layer in one of the interferometer arms. It is experimentally shown that in using an ultra-low coherence light source, the formation of the interference signal is also determined by the group velocity dispersion, which results in a nonlinear dependence of the position of the interference signal on the geometrical thickness of the dispersive layer. The discrepancy in the dispersive layer and compensator refractive indices in the third decimal place is experimentally shown to lead to an interference signal shift that is an order of magnitude greater than the pulse width. (interferometry)

  4. Interferometry

    Totzeck, Michael

    The intention of this chapter is to provide a fast and comprehensive overview of the principles of interferometry and the various types of interferometer, including interferogram evaluation and applications. Due to the age and the importance of the subject, you can find a number of monographs [16.1,2,3,4] and book chapters [16.5] in the literature. The number of original papers on optical interferometry is far too large to even attempt complete coverage in this chapter. Whenever possible, review papers are cited. Original papers are cited according to their aptness as starting points into the subject. This, however, reflects my personal judgment. Even if you do not share my opinion, you should find the references therein useful.

  5. Interferometry

    Ridgway, Stephen; Wilson, Robert W.; Begelman, Mitchell C.; Bender, Peter; Burke, Bernard F.; Cornwell, Tim; Drever, Ronald; Dyck, H. Melvin; Johnston, Kenneth J.; Kibblewhite, Edward

    1991-01-01

    The following recommended programs are reviewed: (1) infrared and optical interferometry (a ground-based and space programs); (2) compensation for the atmosphere with adaptive optics (a program for development and implementation of adaptive optics); and (3) gravitational waves (high frequency gravitational wave sources (LIGO), low frequency gravitational wave sources (LAGOS), a gravitational wave observatory program, laser gravitational wave observatory in space, and technology development during the 1990's). Prospects for international collaboration and related issues are also discussed.

  6. Measuring the Dispersion in Laser Cavity Mirrors using White-Light Interferometry

    2008-03-01

    mirrors. Two AlGaInP (aluminum gallium indium phosphide ) diode lasers are aligned such that one is polarized vertically while one is polarized...linear crystals, where the index of refraction depends on beam intensity. Short pulses with high peak intensities are well 14 suited to induce the...MEASURING THE DISPERSION OF LASER CAVITY MIRRORS USING WHITE-LIGHT INTERFEROMETRY THESIS Allison S

  7. Projekt EDI / Priit Põdra

    Põdra, Priit, 1963-

    2000-01-01

    Projekt EDI töötab välja programmisüsteemi rahvusvaheliste kaubavedude korraldamiseks, dokumentide vormistamiseks ja firmade arvutiprogrammide koostöö korraldamiseks. Projekti tutvustab AS-i EDI VEKTOR juhatuse esimees Priit Põdra

  8. EDIS Investigation Filing Information

    US International Trade Commission — This dataset contains investigation, document and attachment metadata from the USITC's Electronic Document Information System (EDIS), as well as access to attached...

  9. Absolute distance measurement with correction of air refractive index by using two-color dispersive interferometry.

    Wu, Hanzhong; Zhang, Fumin; Liu, Tingyang; Li, Jianshuang; Qu, Xinghua

    2016-10-17

    Two-color interferometry is powerful for the correction of the air refractive index especially in the turbulent air over long distance, since the empirical equations could introduce considerable measurement uncertainty if the environmental parameters cannot be measured with sufficient precision. In this paper, we demonstrate a method for absolute distance measurement with high-accuracy correction of air refractive index using two-color dispersive interferometry. The distances corresponding to the two wavelengths can be measured via the spectrograms captured by a CCD camera pair in real time. In the long-term experiment of the correction of air refractive index, the experimental results show a standard deviation of 3.3 × 10-8 for 12-h continuous measurement without the precise knowledge of the environmental conditions, while the variation of the air refractive index is about 2 × 10-6. In the case of absolute distance measurement, the comparison with the fringe counting interferometer shows an agreement within 2.5 μm in 12 m range.

  10. EDI-The Future.

    Rusk, Harriet J.

    1991-01-01

    Considered are standardization efforts of the American National Standards Institute's Accredited Standards Committee X12 concerned with electronic data interchange (EDI). These efforts will effect dentistry first in the transmission of academic records, and then in communications between dental offices and businesses, including major insurance…

  11. EDI in the Public Sector

    Falch, Morten

    1998-01-01

    Introduction of EDI in the public administration is apriority for the Danish Government. EDI is both seen as a catlyst for development towards an information society ans as a means for more efficient use of scarce resources. EDI in the banking sector and the retail sector is reviewed, drivers...

  12. Measurement of the influence of dispersion on white-light interferometry

    Pavlíček, Pavel; Soubusta, Jan

    2004-01-01

    Roč. 43, č. 4 (2004), s. 766-770 ISSN 0003-6935 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010921 Keywords : white-light interferometry * height profile * smooth surface Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.799, year: 2004

  13. Introduction of EDI in the public sector

    Falch, Morten

    1997-01-01

    Reviews the status of EDI in the sectors of health, public transport and taxation and public administration. The impact of this on the diffusion of EDI in other sectors is analysed.......Reviews the status of EDI in the sectors of health, public transport and taxation and public administration. The impact of this on the diffusion of EDI in other sectors is analysed....

  14. Measurement of chromatic dispersion of microstructured polymer fibers by white-light spectral interferometry

    Hlubina, Petr; Ciprian, Dalibor; Frosz, Michael Henoch

    2009-01-01

    We present a white-light spectral interferometric method for measuring the chromatic dispersion of microstructured fibers made of polymethyl methacrylate (PMMA). The method uses an unbalanced Mach-Zehnder interferometer with the fiber of known length placed in one of the interferometer arms...... of the method by measuring the wavelength dependence of the differential group refractive index of a pure silica fiber. We apply a five-term power series fit to the measured data and confirm by its differentiation that the chromatic dispersion of pure silica glass agrees well with theory. Second, we measure...... the chromatic dispersion for the fundamental mode supported by two different PMMA microstructured fibers, the multimode fiber and the large-mode area one....

  15. EDI and the Technical Communicator.

    Eiler, Mary Ann

    1994-01-01

    Assesses the role of technical communicators in electronic data interchange (EDI). Argues that, as experts in information design, human factors, instructional theory, and professional writing, technical communicators should be advocates of standard documentation protocols and should rethink the traditional concepts of "document" to…

  16. THEORY OF DISPERSED FIXED-DELAY INTERFEROMETRY FOR RADIAL VELOCITY EXOPLANET SEARCHES

    Van Eyken, Julian C.; Ge Jian; Mahadevan, Suvrath

    2010-01-01

    The dispersed fixed-delay interferometer (DFDI) represents a new instrument concept for high-precision radial velocity (RV) surveys for extrasolar planets. A combination of a Michelson interferometer and a medium-resolution spectrograph, it has the potential for performing multi-object surveys, where most previous RV techniques have been limited to observing only one target at a time. Because of the large sample of extrasolar planets needed to better understand planetary formation, evolution, and prevalence, this new technique represents a logical next step in instrumentation for RV extrasolar planet searches, and has been proven with the single-object Exoplanet Tracker (ET) at Kitt Peak National Observatory, and the multi-object W. M. Keck/MARVELS Exoplanet Tracker at Apache Point Observatory. The development of the ET instruments has necessitated fleshing out a detailed understanding of the physical principles of the DFDI technique. Here we summarize the fundamental theoretical material needed to understand the technique and provide an overview of the physics underlying the instrument's working. We also derive some useful analytical formulae that can be used to estimate the level of various sources of error generic to the technique, such as photon shot noise when using a fiducial reference spectrum, contamination by secondary spectra (e.g., crowded sources, spectroscopic binaries, or moonlight contamination), residual interferometer comb, and reference cross-talk error. Following this, we show that the use of a traditional gas absorption fiducial reference with a DFDI can incur significant systematic errors that must be taken into account at the precision levels required to detect extrasolar planets.

  17. Internal control in an EDI environment.

    Bae, Dal Hyeoung

    1991-01-01

    Approved for public release; distribution in unlimited. Electronic Data Interchange(EDI) is the electronic transmission of standard business documents in machine-readable format between parent companies and respective trading partners. As the use of EDI has grown, there have been the associated risks due to an uncontrolled environment. Accordingly, the necessity for effective internal controls in an EDI environment is on the rise. This thesis evaluates and analyzes the feasi...

  18. Characterization and control of the electro-optic phase dispersion in lithium niobate modulators for wide spectral band interferometry applications in the mid-infrared.

    Heidmann, S; Ulliac, G; Courjal, N; Martin, G

    2017-05-10

    Mid-infrared wideband modulation (3.2-3.7 μm) is achieved in an electro-optic Y-junction using lithium niobate waveguides in TE polarized light. Comparison between external (scanning mirror) and internal (electro-optical) modulation allows studying the chromatic polynomial dependence of the relative phase. Internal modulation consists on a V AC ramp up to 370 V at 0.25 Hz, applied over 14 mm long electrodes with 14 μm separation. The overall V π L π obtained is 17.5 V·cm, meaning that using a 300 V generator we can actively scan and track the whole L-band (3.4-4.1 μm) wideband fringes. We observe a dramatic reduction of the coherence length under electro-optic modulation, which is attributed to a strong nonlinear dependence of the electro-optic effect on the wavelength upon application of such high voltages. We study the effect of applying a V DC offset, from -50  V to 200 V (50 V step). We characterize this dispersion and propose an improved dispersion model that is used to show active dispersion compensation in wideband fringe modulation in the mid-infrared. This can be useful for long baseline interferometry or pulse compression applications when light propagates along fibers, in order to compensate for chromatic effects that induce differential dispersion or pulse spreading, respectively.

  19. Efficient Processing Of Voluminous EDI Documents

    Risse, T.; Wombacher, Andreas; Aberer, K.

    Business data is frequently exchanged between heterogeneous information systems using standard EDI formats like EDIFACT, X12 and in the future also XML/EDI. For inhouse use, data represented in these formats must be converted to inhouse data formats by message converters. With the growing usage of

  20. Measuring polarization dependent dispersion of non-polarizing beam splitter cubes with spectrally resolved white light interferometry

    Csonti, K.; Hanyecz, V.; Mészáros, G.; Kovács, A. P.

    2017-06-01

    In this work we have measured the group-delay dispersion of an empty Michelson interferometer for s- and p-polarized light beams applying two different non-polarizing beam splitter cubes. The interference pattern appearing at the output of the interferometer was resolved with two different spectrometers. It was found that the group-delay dispersion of the empty interferometer depended on the polarization directions in case of both beam splitter cubes. The results were checked by inserting a glass plate in the sample arm of the interferometer and similar difference was obtained for the two polarization directions. These results show that to reach high precision, linearly polarized white light beam should be used and the residual dispersion of the empty interferometer should be measured at both polarization directions.

  1. Kaon interferometry

    Roldao, C.G.; Padula, S.S.

    1994-01-01

    Preliminary results of the χ 2 analysis where data on kaon interferometry, obtained from the E859 Collaboration of the AGS/Brookhaven Nat.Lab., are compared with results of a hadronic resonance production model are presented. The main goal is to test the resolution power of the method here discussed when applied to the two-dimensional kaon interferometry

  2. Parsimonious Surface Wave Interferometry

    Li, Jing

    2017-10-24

    To decrease the recording time of a 2D seismic survey from a few days to one hour or less, we present a parsimonious surface-wave interferometry method. Interferometry allows for the creation of a large number of virtual shot gathers from just two reciprocal shot gathers by crosscoherence of trace pairs, where the virtual surface waves can be inverted for the S-wave velocity model by wave-equation dispersion inversion (WD). Synthetic and field data tests suggest that parsimonious wave-equation dispersion inversion (PWD) gives S-velocity tomograms that are comparable to those obtained from a full survey with a shot at each receiver. The limitation of PWD is that the virtual data lose some information so that the resolution of the S-velocity tomogram can be modestly lower than that of the S-velocity tomogram inverted from a conventional survey.

  3. Parsimonious Surface Wave Interferometry

    Li, Jing; Hanafy, Sherif; Schuster, Gerard T.

    2017-01-01

    To decrease the recording time of a 2D seismic survey from a few days to one hour or less, we present a parsimonious surface-wave interferometry method. Interferometry allows for the creation of a large number of virtual shot gathers from just two reciprocal shot gathers by crosscoherence of trace pairs, where the virtual surface waves can be inverted for the S-wave velocity model by wave-equation dispersion inversion (WD). Synthetic and field data tests suggest that parsimonious wave-equation dispersion inversion (PWD) gives S-velocity tomograms that are comparable to those obtained from a full survey with a shot at each receiver. The limitation of PWD is that the virtual data lose some information so that the resolution of the S-velocity tomogram can be modestly lower than that of the S-velocity tomogram inverted from a conventional survey.

  4. Electronic Transcripts--EDI in Academic Administration.

    Carson, E. W.

    1991-01-01

    Newly developed electronic data interchange (EDI) standards for exchanging academic records between colleges and universities are explained. It is argued that implementation of the new standards in college registrar and admissions offices can improve speed, costs, and accuracy and provide a prototype for a variety of campus business applications.…

  5. Ability of EDI-2 and EDI-3 to correctly identify patients and subjects at risk for eating disorders.

    Segura-García, Cristina; Aloi, Matteo; Rania, Marianna; Ciambrone, Paola; Palmieri, Antonella; Pugliese, Valentina; Ruiz Moruno, Antonio José; De Fazio, Pasquale

    2015-12-01

    The prevention and early recognition of eating disorders (EDs) are important topics in public health. This study aims to compare the efficacy of the Eating Disorder Inventory 2 (EDI-2) with the new version, EDI-3 in recognising patients and identifying subjects at risk for EDs. The EDI-2 and EDI-3 were administered to 92 female patients with ED and 265 females from a population at risk for EDs. Experienced psychiatrists in this field held blind interviews with participants by means of the SCID-I to determine the diagnosis. According to the cut-offs suggested by the authors, the EDI-3 correctly identified nearly all of the ED patients (99%), while the EDI-2 divulged less than half (48%). Both versions of the test showed comparable capability to identify participants at risk for EDs but the EDI-3 seemed slightly more reliable than the EDI-2. The EDI-2 remains a valid and very specific test. However, the new EDI-3 seems to be experimentally superior, because it typifies nearly all patients across the ED span, including those with Binge Eating Disorder and Eating Disorder Not Otherwise Specified. In addition, it appears to be more reliable. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Atomic interferometry

    Baudon, J.; Robert, J.

    2004-01-01

    Since the theoretical works of L. De Broglie (1924) and the famous experiment of Davisson and Germer (1927), we know that a wave is linked with any particle of mass m by the relation λ = h/(mv), where λ is the wavelength, v the particle velocity and h is the Planck constant. The basic principle of the interferometry of any material particle, atom, molecule or aggregate is simple: using a simple incident wave, several mutually consistent waves (with well-defined relative phases) are generated and controllable phase-shifts are introduced between them in order to generate a wave which is the sum of the previous waves. An interference figure is obtained which consists in a succession of dark and bright fringes. The atomic interferometry is based on the same principle but involves different techniques, different wave equations, but also different beams, sources and correlations which are described in this book. Because of the small possible wavelengths and the wide range of possible atomic interactions, atomic interferometers can be used in many domains from the sub-micron lithography to the construction of sensors like: inertial sensors, gravity-meters, accelerometers, gyro-meters etc. The first chapter is a preliminary study of the space and time diffraction of atoms. The next chapters is devoted to the description of slit, light separation and polarization interferometers, and the last chapter treats of the properties of Bose-Einstein condensates which are interesting in atomic interferometry. (J.S.)

  7. Electronic Data Interchange (EDI) for Libraries and Publishers.

    Santosuosso, Joe

    1992-01-01

    Defines electronic data interchange (EDI) as the exchange of data between computer systems without human intervention or interpretation. Standards are discussed; and the implementation of EDI in libraries and the serials publishing community in the areas of orders and acquisitions, claims, and invoice processing is described. (LRW)

  8. Cinco translações, 10 edições

    Ângela Tonietto; Bruno Telles; Charles A. Andrade; Claudemir R. Dias Filho; Juliano A. Gomes

    2016-01-01

    Após cinco translações em torno da estrela do Sistema Solar e nove edições publicadas, a Revista Brasileira de Criminalística entrega hoje o terceiro número do seu quinto volume, completando assim cinco anos ininterruptos de publicações com sua décima edição.

  9. Speckle interferometry

    Sirohi, Rajpal S.

    2002-03-01

    Illumination of a rough surface by a coherent monochromatic wave creates a grainy structure in space termed a speckle pattern. It was considered a special kind of noise and was the bane of holographers. However, its information-carrying property was soon discovered and the phenomenon was used for metrological applications. The realization that a speckle pattern carried information led to a new measurement technique known as speckle interferometry (SI). Although the speckle phenomenon in itself is a consequence of interference among numerous randomly dephased waves, a reference wave is required in SI. Further, it employs an imaging geometry. Initially SI was performed mostly by using silver emulsions as the recording media. The double-exposure specklegram was filtered to extract the desired information. Since SI can be configured so as to be sensitive to the in-plane displacement component, the out-of-plane displacement component or their derivatives, the interferograms corresponding to these were extracted from the specklegram for further analysis. Since the speckle size can be controlled by the F number of the imaging lens, it was soon realized that SI could be performed with electronic detection, thereby increasing its accuracy and speed of measurement. Furthermore, a phase-shifting technique can also be incorporated. This technique came to be known as electronic speckle pattern interferometry (ESPI). It employed the same experimental configurations as SI. ESPI found many industrial applications as it supplements holographic interferometry. We present three examples covering diverse areas. In one application it has been used to measure residual stress in a blank recordable compact disk. In another application, microscopic ESPI has been used to study the influence of relative humidity on paint-coated figurines and also the effect of a conservation agent applied on top of this. The final application is to find the defects in pipes. These diverse applications

  10. Business Process Redesign Using EDI: the BHP steel experience

    Paula Swatman

    1994-05-01

    Full Text Available EDI should not be seen as a competitive weapon - it does not offer a sustainable competitive advantage to its users as did the earlier inter-organisational systems (such as the various airline reservation systems. Instead EDI provides a standardised infrastructure upon which an adopting organisation can reengineer its business processes and thus confers a long-term, strategic and comparative advantage upon such an adopter. The potential for sustained competitive advantage to be derived from EDI arises from its integration with the organisational structure of its implementor, depending upon the implementing organisation's ability to redesign its business processes appropriately. This paper examines the case of (arguably the most sophisticated EDI-using company in Australia, BHP Steel, demonstrating the advantages obtainable by an organisation using EDI as a foundation for its reengineered organisational structure and business processes and concludes that: • there are real benefits to be obtained from an inter organisational electronic trading strategy founded on EDI as the enabling mechanism - benefits which are considerably more extensive than EDI's comparatively simple technical nature would appear to offer; • organisational gateways utilising an Application Generic approach to system integration and isolating the communications issue by insisting on the use of international data communications standards do offer a realistic and successful solution to the problem of internal and external trade for large and sophisticated organisations; • the majority of these achievements would have been either unlikely or totally impossible without BHP Steel's commitment to organisation-wide Business Process Redesign.

  11. Development of the Electron Drift Instrument (EDI) for Cluster

    Quinn, Jack; Christensen, John L. (Technical Monitor)

    2001-01-01

    The Electron Drift Instrument (EDI) is a new technique for measuring electric fields in space by detecting the effect on weak beams of test electrons. This U.S. portions of the technique, flight hardware, and flight software were developed for the Cluster mission under this contract. Dr. Goetz Paschmann of the Max Planck Institute in Garching, Germany, was the Principle Investigator for Cluster EDI. Hardware for Cluster was developed in the U.S. at the University of New Hampshire, Lockheed Palo Alto Research Laboratory, and University of California, San Diego. The Cluster satellites carrying the original EDI instruments were lost in the catastrophic launch failure of first flight of the Arianne-V rocket in 1996. Following that loss, NASA and ESA approved a rebuild of the Cluster mission, for which all four satellites were successfully launched in the Summer of 2000. Limited operations of EDI were also obtained on the Equator-S satellite, which was launched in December, 1997. A satellite failure caused a loss of the Equator-S mission after only 5 months, but these operations were extremely valuable in learning about the characteristics and operations of the complex EDI instrument. The Cluster mission, satellites, and instruments underwent an extensive on-orbit commissioning phase in the Fall of 2000, carrying over through January 2001. During this period all elements of the instruments were checked and careful measurements of inter-experiments interferences were made. EDI is currently working exceptionally well in orbit. Initial results verify that all aspects of the instrument are working as planned, and returning highly valuable scientific information. The first two papers describing EDI on-orbit results have been submitted for publication in April, 2001. The principles of the EDI technique, and its implementation on Cluster are described in two papers by Paschmann et al., attached as Appendices A and B. The EDI presentation at the formal Cluster Commissioning

  12. Speckle Interferometry

    Chiang, F. P.; Jin, F.; Wang, Q.; Zhu, N.

    Before the milestone work of Leedertz in 1970 coherent speckles generated from a laser illuminated object are considered noise to be eliminated or minimized. Leedertz shows that coherent speckles are actually information carriers. Since then the speckle technique has found many applications to fields of mechanics, metrology, nondestructive evaluation and material sciences. Speckles need not be coherent. Artificially created socalled white light speckles can also be used as information carriers. In this paper we present two recent developments of speckle technique with applications to micromechanics problems using SIEM (Speckle Interferometry with Electron Microscopy), to nondestructive evaluation of crevice corrosion and composite disbond and vibration of large structures using TADS (Time-Average Digital Specklegraphy).

  13. Binary trading relations and the limits of EDI standards

    Damsgaard, Jan; Truex, D.

    2000-01-01

    This paper provides a critical examination of electronic data interchange (EDI) standards and their application in different types of trading relationships. It argues that EDI standards are not directly comparable to more stable sets of technical standards in that they are dynamically tested...... and negotiated in use with each trading exchange. It takes the position that EDI standards are an emergent language form and must mean different things at the institutional and local levels. Using the lens of emergent linguistic analysis it shows how the institutional and local levels must always be distinct...... and yet can coexist. EDI standards can never represent the creation of an 'Esperanto of institutional communication'. Instead we believe that standards must be developed such that they support and accommodate general basic grammatical forms that can be customised to individual needs. The analysis...

  14. [A German version of the Eating Disorder Inventory EDI-2].

    Thiel, A; Jacobi, C; Horstmann, S; Paul, T; Nutzinger, D O; Schüssler, G

    1997-01-01

    The paper presents a German version of the second revised edition of the Eating Disorder Inventory EDI-2 (Garner 1991). The EDI-2 is a self-rating inventory (self-report measure) with 91 items and 11 subscales designed for the assessment of attitudinal and behavioural dimensions relevant to anorexia and bulimia nervosa. It consists of the eight original subscales: drive for thinness, bulimia, body dissatisfaction, ineffectiveness, perfectionism, interpersonal distrust, interoception and maturity fears, and the three new subscales: asceticism, impulse regulation and social insecurity. The German EDI-2 was given to 71 patients with anorexia or bulimia nervosa, 30 patients with binge eating disorder, a control group of 186 women and a further control group of 102 men. In comparison to the female control group, patient groups showed significantly elevated means on all subscales. Item analysis revealed sufficient internal consistencies for all subscales except subscale 9 (asceticism) with Cronbachs alpha ranging from 0.58 to 0.90. Twelve of the 91 items showed poor item total scale correlations below 0.40. Factor analysis supported a six-factor-structure. Hence, the reliability and validity of the three new subscales was confirmed only partially. The use of the EDI-2 in therapy research and clinical practice is critically discussed.

  15. The ISO Edi Conceptual Model Activity and Its Relationship to OSI.

    Fincher, Judith A.

    1990-01-01

    The edi conceptual model is being developed to define common structures, services, and processes that syntax-specific standards like X12 and EDIFACT could adopt. Open Systems Interconnection (OSI) is of interest to edi because of its potential to help enable global interoperability across Electronic Data Interchange (EDI) functional groups. A…

  16. Interferometry with polarised neutrons

    Badurek, G.

    1978-01-01

    This paper aimed to give an outline of what might be expected from an extension of polarized beam techniques in neutron interferometry and how it could be achieved properly and what is the present state of this special field of interferometry

  17. Optical interferometry in astronomy

    Monnier, John D

    2003-01-01

    Here I review the current state of the field of optical stellar interferometry, concentrating on ground-based work although a brief report of space interferometry missions is included. We pause both to reflect on decades of immense progress in the field as well as to prepare for a new generation of large interferometers just now being commissioned (most notably, the CHARA, Keck and VLT Interferometers). First, this review summarizes the basic principles behind stellar interferometry needed by the lay-physicist and general astronomer to understand the scientific potential as well as technical challenges of interferometry. Next, the basic design principles of practical interferometers are discussed, using the experience of past and existing facilities to illustrate important points. Here there is significant discussion of current trends in the field, including the new facilities under construction and advanced technologies being debuted. This decade has seen the influence of stellar interferometry extend beyond classical regimes of stellar diameters and binary orbits to new areas such as mapping the accretion discs around young stars, novel calibration of the cepheid period-luminosity relation, and imaging of stellar surfaces. The third section is devoted to the major scientific results from interferometry, grouped into natural categories reflecting these current developments. Lastly, I consider the future of interferometry, highlighting the kinds of new science promised by the interferometers coming on-line in the next few years. I also discuss the longer-term future of optical interferometry, including the prospects for space interferometry and the possibilities of large-scale ground-based projects. Critical technological developments are still needed to make these projects attractive and affordable

  18. Optomechanical fabrication of EDiFiSE spectrometer

    Arredondo-Vega, Luis; Pérez-Santos, Carlos; Pompa-Carrera, Octavio; Ruiz-Márquez, Armando; Hurtado-Ortega, José; Paez, Gonzalo

    2011-09-01

    The purpose of this work is to describe some optical and mechanical issues relating to the fabrication of the camera and the collimator of the Equalized and Diffraction-Limited Field Spectrograph Experiment (EDiFiSE), an instrument which forms part of a bigger project of the Instituto de Astrofísica de Canarias (IAC), Spain, and that was designed and manufactured within the facilities of Centro de Investigaciones en Óptica in León, México.

  19. Edição Especial: 6 V-EEGAM

    João Cândido André da Silva Neto; Thiago Oliveira Neto

    2017-01-01

    A sexta edição especial da Revista Geonorte acaba de ser publicada, contemplando os trabalhos submetidos e aceitos ao V Encontro dos Estudantes de Geografia do Amazonas-EEGAM com o tema: Geografia da Circulação, realizado nas dependências do Instituto de Ciências Humanas e Letras-ICHL entre 29 e 30 de novembro e 01 e 02 de dezembro de 2016.

  20. Edição Especial: 6 V-EEGAM

    João Cândido André da Silva Neto

    2017-05-01

    Full Text Available A sexta edição especial da Revista Geonorte acaba de ser publicada, contemplando os trabalhos submetidos e aceitos ao V Encontro dos Estudantes de Geografia do Amazonas-EEGAM com o tema: Geografia da Circulação, realizado nas dependências do Instituto de Ciências Humanas e Letras-ICHL entre 29 e 30 de novembro e 01 e 02 de dezembro de 2016.

  1. Principles of Stellar Interferometry

    Glindemann, Andreas

    2011-01-01

    Over the last decade, stellar interferometry has developed from a specialist tool to a mainstream observing technique, attracting scientists whose research benefits from milliarcsecond angular resolution. Stellar interferometry has become part of the astronomer’s toolbox, complementing single-telescope observations by providing unique capabilities that will advance astronomical research. This carefully written book is intended to provide a solid understanding of the principles of stellar interferometry to students starting an astronomical research project in this field or to develop instruments and to astronomers using interferometry but who are not interferometrists per se. Illustrated by excellent drawings and calculated graphs the imaging process in stellar interferometers is explained starting from first principles on light propagation and diffraction wave propagation through turbulence is described in detail using Kolmogorov statistics the impact of turbulence on the imaging process is discussed both f...

  2. Determinants of EDI (Electronic Data Interchange) Adoption and Integration in the US and Japanese Automobile Suppliers

    Sam Kurokawa; Seiji Manabe

    2002-01-01

    This paper examines determinants of EDI adoption and integration in the US and Japanese automobile suppliers. The paper constructs several hypotheses based on the transaction-cost and resource- dependence approaches, and tests these hypotheses by using data from the automobile suppliers. Our study shows: (1) the resource-dependence approach seemed more effective in explaining EDI adoption, while the transaction-cost approach seemed more effective in explaining EDI integration; (2) the transac...

  3. Pro EDI in BizTalk Server 2006 R2 electronic document interchange solutions

    Beckner, Mark

    2008-01-01

    As business becomes more dependent on working with partners, suppliers, and other organizations in a streamlined way, Electronic Data Interchange (EDI) is one of the next big waves in connected systems. Microsoft BizTalk Server 2006 R2 offers an efficient, integrated way to deploy EDI solutions, and with the help of this book, readers will see how EDI can be used in their business and how best to get it set up with BizTalk. This book offers insights into the brand-new Biztalk 2006 R2--based EDI functionality, including the far greater flexibility in handling interchange. It gives advice coveri

  4. The new Exponential Directional Iterative (EDI) 3-D Sn scheme for parallel adaptive differencing

    Sjoden, G.E.

    2005-01-01

    The new Exponential Directional Iterative (EDI) discrete ordinates (Sn) scheme for 3-D Cartesian Coordinates is presented. The EDI scheme is a logical extension of the positive, efficient Exponential Directional Weighted (EDW) Sn scheme currently used as the third level of the adaptive spatial differencing algorithm in the PENTRAN parallel discrete ordinates solver. Here, the derivation and advantages of the EDI scheme are presented; EDI uses EDW-rendered exponential coefficients as initial starting values to begin a fixed point iteration of the exponential coefficients. One issue that required evaluation was an iterative cutoff criterion to prevent the application of an unstable fixed point iteration; although this was needed in some cases, it was readily treated with a default to EDW. Iterative refinement of the exponential coefficients in EDI typically converged in fewer than four fixed point iterations. Moreover, EDI yielded more accurate angular fluxes compared to the other schemes tested, particularly in streaming conditions. Overall, it was found that the EDI scheme was up to an order of magnitude more accurate than the EDW scheme on a given mesh interval in streaming cases, and is potentially a good candidate as a fourth-level differencing scheme in the PENTRAN adaptive differencing sequence. The 3-D Cartesian computational cost of EDI was only about 20% more than the EDW scheme, and about 40% more than Diamond Zero (DZ). More evaluation and testing are required to determine suitable upgrade metrics for EDI to be fully integrated into the current adaptive spatial differencing sequence in PENTRAN. (author)

  5. Cost-Effective Magnetoencephalography Based on Time Encoded Optical Fiber Interferometry for Epilepsy and Tinnitus

    2016-09-01

    respectively. A length of dispersive fiber and a computer are used to first “decode” the optical interference signal into dispersed optical wave-packet...AWARD NUMBER: W81XWH-15-1-0008 TITLE: Cost-Effective Magnetoencephalography Based on Time-Encoded Optical Fiber Interferometry for Epilepsy...10 Dec 2014 - 9 Jun 2016 4. TITLE AND SUBTITLE 5a.16 CONTRACT NUMBER Encoded Optical Fiber Interferometry for Epilepsy and Tinnitus Diagnosis 5b

  6. Measurement Invariance of Early Development Instrument (EDI) Domain Scores across Gender and ESL Status

    Mousavi, Amin; Krishnan, Vijaya

    2016-01-01

    The Early Development Instrument (EDI) is a widely used teacher rating tool to assess kindergartners' developmental outcomes in Canada and a number of other countries. This paper examines the measurement invariance of EDI domains across ESL status and gender by means of multi-group confirmatory factor analysis. The results suggest evidence of…

  7. Does the EDI Equivalently Measure Facets of School Readiness for Aboriginal and Non-Aboriginal Children?

    Muhajarine, Nazeem; Puchala, Chassidy; Janus, Magdalena

    2011-01-01

    The aim of the current paper was to examine the equivalence of the Early Development Instrument (EDI), a teacher rating measure of school readiness, for Aboriginal and non-Aboriginal children. The current study used an approach, which analyzes the structure and properties of the EDI at the subdomain level. Similar subdomain score distributions…

  8. 41 CFR 102-118.550 - How does a TSP file an administrative claim using EDI or other electronic means?

    2010-07-01

    ... administrative claim using EDI or other electronic means? 102-118.550 Section 102-118.550 Public Contracts and... EDI or other electronic means? The medium and precise format of data for an administrative claim filed electronically must be approved in advance by the GSA Audit Division. GSA will use an authenticating EDI...

  9. Statistical properties of effective drought index (EDI) for Seoul, Busan, Daegu, Mokpo in South Korea

    Park, Jong-Hyeok; Kim, Ki-Beom; Chang, Heon-Young

    2014-08-01

    Time series of drought indices has been considered mostly in view of temporal and spatial distributions of a drought index so far. Here we investigate the statistical properties of a daily Effective Drought Index (EDI) itself for Seoul, Busan, Daegu, Mokpo for the period of 100 years from 1913 to 2012. We have found that both in dry and wet seasons the distribution of EDI as a function of EDI follows the Gaussian function. In dry season the shape of the Gaussian function is characteristically broader than that in wet seasons. The total number of drought days during the period we have analyzed is related both to the mean value and more importantly to the standard deviation. We have also found that according to the distribution of the number of occasions where the EDI values of several consecutive days are all less than a threshold, the distribution follows the exponential distribution. The slope of the best fit becomes steeper not only as the critical EDI value becomes more negative but also as the number of consecutive days increases. The slope of the exponential distribution becomes steeper as the number of the city in which EDI is simultaneously less than a critical EDI in a row increases. Finally, we conclude by pointing out implications of our findings.

  10. Iterative supervirtual refraction interferometry

    Al-Hagan, Ola

    2014-05-02

    In refraction tomography, the low signal-to-noise ratio (S/N) can be a major obstacle in picking the first-break arrivals at the far-offset receivers. To increase the S/N, we evaluated iterative supervirtual refraction interferometry (ISVI), which is an extension of the supervirtual refraction interferometry method. In this method, supervirtual traces are computed and then iteratively reused to generate supervirtual traces with a higher S/N. Our empirical results with both synthetic and field data revealed that ISVI can significantly boost up the S/N of far-offset traces. The drawback is that using refraction events from more than one refractor can introduce unacceptable artifacts into the final traveltime versus offset curve. This problem can be avoided by careful windowing of refraction events.

  11. Vibration insensitive interferometry

    Millerd, James; Brock, Neal; Hayes, John; Kimbrough, Brad; North-Morris, Michael; Wyant, James C.

    2017-11-01

    The largest limitation of phase-shifting interferometry for optical testing is the sensitivity to the environment, both vibration and air turbulence. An interferometer using temporal phase-shifting is very sensitive to vibration because the various phase shifted frames of interferometric data are taken at different times and vibration causes the phase shifts between the data frames to be different from what is desired. Vibration effects can be reduced by taking all the phase shifted frames simultaneously and turbulence effects can be reduced by averaging many measurements. There are several techniques for simultaneously obtaining several phase-shifted interferograms and this paper will discuss two such techniques: 1) Simultaneous phase-shifting interferometry on a single detector array (PhaseCam) and 2) Micropolarizer phase-shifting array. The application of these techniques for the testing of large optical components, measurement of vibrational modes, the phasing of segmented optical components, and the measurement of deformations of large diffuse structures is described.

  12. Iterative supervirtual refraction interferometry

    Al-Hagan, Ola; Hanafy, Sherif M.; Schuster, Gerard T.

    2014-01-01

    In refraction tomography, the low signal-to-noise ratio (S/N) can be a major obstacle in picking the first-break arrivals at the far-offset receivers. To increase the S/N, we evaluated iterative supervirtual refraction interferometry (ISVI), which is an extension of the supervirtual refraction interferometry method. In this method, supervirtual traces are computed and then iteratively reused to generate supervirtual traces with a higher S/N. Our empirical results with both synthetic and field data revealed that ISVI can significantly boost up the S/N of far-offset traces. The drawback is that using refraction events from more than one refractor can introduce unacceptable artifacts into the final traveltime versus offset curve. This problem can be avoided by careful windowing of refraction events.

  13. Scope of neutron interferometry

    Rauch, H.

    1978-01-01

    This paper deals with the interferometry of well separated coherent beams, where the phase of the beams can be manipulated individually. The basic equation of the dynamical neutron diffraction theory are recalled. The various contributions to the interaction of as low neutron with its surroundings are discussed: the various terms denote the nuclear, magnetic, electromagnetic, intrinsic, gravitational, and weak interaction respectively. Applications to nuclear physics, fundamental physics and solid state physics are successively envisaged

  14. Space Interferometry Science Working Group

    Ridgway, Stephen T.

    1992-12-01

    Decisions taken by the astronomy and astrophysics survey committee and the interferometry panel which lead to the formation of the Space Interferometry Science Working Group (SISWG) are outlined. The SISWG was formed by the NASA astrophysics division to provide scientific and technical input from the community in planning for space interferometry and in support of an Astrometric Interferometry Mission (AIM). The AIM program hopes to measure the positions of astronomical objects with a precision of a few millionths of an arcsecond. The SISWG science and technical teams are described and the outcomes of its first meeting are given.

  15. Magnetic field gradients inferred from multi-point measurements of Cluster FGM and EDI

    Teubenbacher, Robert; Nakamura, Rumi; Giner, Lukas; Plaschke, Ferdinand; Baumjohann, Wolfgang; Magnes, Werner; Eichelberger, Hans; Steller, Manfred; Torbert, Roy

    2013-04-01

    We use Cluster data from fluxgate magnetometer (FGM) and electron drift instrument (EDI) to determine the magnetic field gradients in the near-Earth magnetotail. Here we use the magnetic field data from FGM measurements as well as the gyro-time data of electrons determined from the time of flight measurements of EDI. The results are compared with the values estimated from empirical magnetic field models for different magnetospheric conditions. We also estimated the spin axis offset of FGM based on comparison between EDI and FGM data and discuss the possible effect in determining the current sheet characteristics.

  16. Interhemispheric differences in ionospheric convection: Cluster EDI observations revisited

    Förster, M.; Haaland, S.

    2015-07-01

    The interaction between the interplanetary magnetic field and the geomagnetic field sets up a large-scale circulation in the magnetosphere. This circulation is also reflected in the magnetically connected ionosphere. In this paper, we present a study of ionospheric convection based on Cluster Electron Drift Instrument (EDI) satellite measurements covering both hemispheres and obtained over a full solar cycle. The results from this study show that average flow patterns and polar cap potentials for a given orientation of the interplanetary magnetic field can be very different in the two hemispheres. In particular during southward directed interplanetary magnetic field conditions, and thus enhanced energy input from the solar wind, the measurements show that the southern polar cap has a higher cross polar cap potential. There are persistent north-south asymmetries, which cannot easily be explained by the influence of external drivers. These persistent asymmetries are primarily a result of the significant differences in the strength and configuration of the geomagnetic field between the Northern and Southern Hemispheres. Since the ionosphere is magnetically connected to the magnetosphere, this difference will also be reflected in the magnetosphere in the form of different feedback from the two hemispheres. Consequently, local ionospheric conditions and the geomagnetic field configuration are important for north-south asymmetries in large regions of geospace.

  17. Antihydrogen Experiment Gravity Interferometry Spectroscopy

    Trezzi, D; Dassa, L; Rienacker, B; Khalidova, O; Ferrari, G; Krasnicky, D; Perini, D; Cerchiari, G; Belov, A; Boscolo, I; Sacerdoti, M G; Ferragut, R O; Nedelec, P; Hinterberger, A; Al-qaradawi, I; Malbrunot, C L S; Brusa, R S; Prelz, F; Manuzio, G; Riccardi, C; Fontana, A; Genova, P; Haider, S; Haug, F; Turbabin, A; Castelli, F; Testera, G; Lagomarsino, V E; Doser, M; Penasa, L; Gninenko, S; Cataneo, F; Zenoni, A; Cabaret, L; Comparat, D P; Zmeskal, J; Scampoli, P; Nesteruk, K P; Dudarev, A; Kellerbauer, A G; Mariazzi, S; Carraro, C; Zavatarelli, S M

    The AEGIS experiment (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) has the aim of carrying out the first measurement of the gravitational interaction of antimatter to a precision of 1%, by applying techniques from atomic physics, laser spectroscopy and interferometry to a beam of antihydrogen atoms. A further goal of the experiment is to carry out spectroscopy of the antihydrogen atoms in flight.

  18. Basics of interferometry

    Hariharan, P

    1992-01-01

    This book is for those who have some knowledge of optics, but little or no previous experience in interferometry. Accordingly, the carefully designed presentation helps readers easily find and assimilate the interferometric techniques they need for precision measurements. Mathematics is held to a minimum, and the topics covered are also summarized in capsule overviews at the beginning and end of each chapter. Each chapter also contains a set of worked problems that give a feel for numbers.The first five chapters present a clear tutorial review of fundamentals. Chapters six and seven discus

  19. Interferometry with atoms

    Helmcke, J.; Riehle, F.; Witte, A.; Kisters, T.

    1992-01-01

    Physics and experimental results of atom interferometry are reviewed and several realizations of atom interferometers are summarized. As a typical example of an atom interferometer utilizing the internal degrees of freedom of the atom, we discuss the separated field excitation of a calcium atomic beam using four traveling laser fields and demonstrate the Sagnac effect in a rotating interferometer. The sensitivity of this interferometer can be largely increased by use of slow atoms with narrow velocity distribution. We therefore furthermore report on the preparation of a laser cooled and deflected calcium atomic beam. (orig.)

  20. Speckle interferometry of asteroids

    Drummond, J.

    1988-01-01

    By studying the image two-dimensional power spectra or autocorrelations projected by an asteroid as it rotates, it is possible to locate its rotational pole and derive its three axes dimensions through speckle interferometry under certain assumptions of uniform, geometric scattering, and triaxial ellipsoid shape. However, in cases where images can be reconstructed, the need for making the assumptions is obviated. Furthermore, the ultimate goal for speckle interferometry of image reconstruction will lead to mapping albedo features (if they exist) as impact areas or geological units. The first glimpses of the surface of an asteroid were obtained from images of 4 Vesta reconstructed from speckle interferometric observations. These images reveal that Vesta is quite Moon-like in having large hemispheric-scale albedo features. All of its lightcurves can be produced from a simple model developed from the images. Although undoubtedly more intricate than the model, Vesta's lightcurves can be matched by a model with three dark and four bright spots. The dark areas so dominate one hemisphere that a lightcurve minimum occurs when the maximum cross-section area is visible. The triaxial ellipsoid shape derived for Vesta is not consistent with the notion that the asteroid has an equilibrium shape in spite of its having apparently been differentiated

  1. Time-Delay Interferometry

    Massimo Tinto

    2014-08-01

    Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  2. Precision measurement with atom interferometry

    Wang Jin

    2015-01-01

    Development of atom interferometry and its application in precision measurement are reviewed in this paper. The principle, features and the implementation of atom interferometers are introduced, the recent progress of precision measurement with atom interferometry, including determination of gravitational constant and fine structure constant, measurement of gravity, gravity gradient and rotation, test of weak equivalence principle, proposal of gravitational wave detection, and measurement of quadratic Zeeman shift are reviewed in detail. Determination of gravitational redshift, new definition of kilogram, and measurement of weak force with atom interferometry are also briefly introduced. (topical review)

  3. Parsimonious refraction interferometry

    Hanafy, Sherif

    2016-09-06

    We present parsimonious refraction interferometry where a densely populated refraction data set can be obtained from just two shot gathers. The assumptions are that the first arrivals are comprised of head waves and direct waves, and a pair of reciprocal shot gathers is recorded over the line of interest. The refraction traveltimes from these reciprocal shot gathers can be picked and decomposed into O(N2) refraction traveltimes generated by N virtual sources, where N is the number of geophones in the 2D survey. This enormous increase in the number of virtual traveltime picks and associated rays, compared to the 2N traveltimes from the two reciprocal shot gathers, allows for increased model resolution and better condition numbers in the normal equations. Also, a reciprocal survey is far less time consuming than a standard refraction survey with a dense distribution of sources.

  4. Interferometry with Vortices

    P. Senthilkumaran

    2012-01-01

    Full Text Available Interference of optical beams with optical vortices is often encountered in singular optics. Since interferometry makes the phase observable by intensity measurement, it brings out a host of applications and helps to understand the optical vortex. In this article we present an optical vortex interferometer that can be used in optical testing and has the potential to increase the accuracy of measurements. In an optical vortex interferometer (OVI, a lattice of vortices is formed, and the movement of the cores of these vortices is tracked when one of the interfering beams is deformed. Instead of multiple vortices in an OVI, an isolated single vortex also finds applications in optical testing. Finally, singularity in scalar and vector fields is presented, and the relation between them is illustrated by the superposition of these beams.

  5. Parsimonious refraction interferometry

    Hanafy, Sherif; Schuster, Gerard T.

    2016-01-01

    We present parsimonious refraction interferometry where a densely populated refraction data set can be obtained from just two shot gathers. The assumptions are that the first arrivals are comprised of head waves and direct waves, and a pair of reciprocal shot gathers is recorded over the line of interest. The refraction traveltimes from these reciprocal shot gathers can be picked and decomposed into O(N2) refraction traveltimes generated by N virtual sources, where N is the number of geophones in the 2D survey. This enormous increase in the number of virtual traveltime picks and associated rays, compared to the 2N traveltimes from the two reciprocal shot gathers, allows for increased model resolution and better condition numbers in the normal equations. Also, a reciprocal survey is far less time consuming than a standard refraction survey with a dense distribution of sources.

  6. Interferometry using undulator sources

    Beguiristain, R.; Goldberg, K.A.; Tejnil, E.; Bokor, J.; Medecki, H.; Attwood, D.T.; Jackson, K.

    1996-01-01

    Optical systems for extreme ultraviolet (EUV) lithography need to use optical components with subnanometer surface figure error tolerances to achieve diffraction-limited performance [M.D. Himel, in Soft X-Ray Projection Lithography, A.M. Hawryluk and R.H. Stulen, eds. (OSA, Washington, D.C., 1993), 18, 1089, and D. Attwood et al., Appl. Opt. 32, 7022 (1993)]. Also, multilayer-coated optics require at-wavelength wavefront measurement to characterize phase effects that cannot be measured by conventional optical interferometry. Furthermore, EUV optical systems will additionally require final testing and alignment at the operational wavelength for adjustment and reduction of the cumulative optical surface errors. Therefore, at-wavelength interferometric measurement of EUV optics will be the necessary metrology tool for the successful development of optics for EUV lithography. An EUV point diffraction interferometer (PDI) has been developed at the Center for X-Ray Optics (CXRO) and has been already in operation for a year [K. Goldberg et al., in Extreme Ultra Lithography, D.T. Attwood and F. Zernike, eds. (OSA, Washington, D.C., 1994), K. Goldberg et al., Proc. SPIE 2437, to be published, and K. Goldberg et al., J. Vac. Sci. Technol. B 13, 2923 (1995)] using an undulator radiation source and coherent optics beamline at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. An overview of the PDI interferometer and some EUV wavefront measurements obtained with this instrument will be presented. In addition, future developments planned for EUV interferometry at CXRO towards the measurement of actual EUV lithography optics will be shown. copyright 1996 American Institute of Physics

  7. Parsimonious Refraction Interferometry and Tomography

    Hanafy, Sherif; Schuster, Gerard T.

    2017-01-01

    We present parsimonious refraction interferometry and tomography where a densely populated refraction data set can be obtained from two reciprocal and several infill shot gathers. The assumptions are that the refraction arrivals are head waves

  8. Phase Referencing in Optical Interferometry

    Filho, Mercedes E.; Garcia, Paulo; Duvert, Gilles; Duchene, Gaspard; Thiebaut, Eric; Young, John; Absil, Olivier; Berger, Jean-Phillipe; Beckert, Thomas; Hoenig, Sebastian; Schertl, Dieter; Weigelt, Gerd; Testi, Leonardo; Tatuli, Eric; Borkowski, Virginie

    2008-01-01

    One of the aims of next generation optical interferometric instrumentation is to be able to make use of information contained in the visibility phase to construct high dynamic range images. Radio and optical interferometry are at the two extremes of phase corruption by the atmosphere. While in radio it is possible to obtain calibrated phases for the science objects, in the optical this is currently not possible. Instead, optical interferometry has relied on closure phase techniques to produce...

  9. Extreme ultraviolet interferometry

    Goldberg, Kenneth A. [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-12-01

    EUV lithography is a promising and viable candidate for circuit fabrication with 0.1-micron critical dimension and smaller. In order to achieve diffraction-limited performance, all-reflective multilayer-coated lithographic imaging systems operating near 13-nm wavelength and 0.1 NA have system wavefront tolerances of 0.27 nm, or 0.02 waves RMS. Owing to the highly-sensitive resonant reflective properties of multilayer mirrors and extraordinarily tight tolerances set forth for their fabrication, EUV optical systems require at-wavelength EUV interferometry for final alignment and qualification. This dissertation discusses the development and successful implementation of high-accuracy EUV interferometric techniques. Proof-of-principle experiments with a prototype EUV point-diffraction interferometer for the measurement of Fresnel zoneplate lenses first demonstrated sub-wavelength EUV interferometric capability. These experiments spurred the development of the superior phase-shifting point-diffraction interferometer (PS/PDI), which has been implemented for the testing of an all-reflective lithographic-quality EUV optical system. Both systems rely on pinhole diffraction to produce spherical reference wavefronts in a common-path geometry. Extensive experiments demonstrate EUV wavefront-measuring precision beyond 0.02 waves RMS. EUV imaging experiments provide verification of the high-accuracy of the point-diffraction principle, and demonstrate the utility of the measurements in successfully predicting imaging performance. Complementary to the experimental research, several areas of theoretical investigation related to the novel PS/PDI system are presented. First-principles electromagnetic field simulations of pinhole diffraction are conducted to ascertain the upper limits of measurement accuracy and to guide selection of the pinhole diameter. Investigations of the relative merits of different PS/PDI configurations accompany a general study of the most significant sources

  10. An arithmetic transference proof of a relative Szemer\\'edi theorem

    Zhao, Yufei

    2013-01-01

    Recently Conlon, Fox, and the author gave a new proof of a relative Szemer\\'edi theorem, which was the main novel ingredient in the proof of the celebrated Green-Tao theorem that the primes contain arbitrarily long arithmetic progressions. Roughly speaking, a relative Szemer\\'edi theorem says that if S is a set of integers satisfying certain conditions, and A is a subset of S with positive relative density, then A contains long arithmetic progressions, and our recent results show that S only ...

  11. Rancang Bangun Aplikasi Transaksi Elektronik Ritel Pupuk Dengan Metode Electronic Data Interchange (EDI

    Nelly Oktavia Adiwijaya

    2015-03-01

    Full Text Available Fertilizer distribution from distributor to agents, are required to be responsive in addressing the demand for fertilizers. Distributors are also required to be able to manage inventory in the warehouse, to avoid overstocking of fertilizer. Design and implementation of a fertilizer retail electronic commerce applications using electronic data interchange (EDI method is applied in this study. The system is built to help distributors to control the existence of the stock of fertilizer so no excess stock. In addition, the use of EDI can provide information quickly (real-time without having to go directly to the warehouse locations.

  12. The EDIE method – towards an approach to collaboration-based persuasive design

    Hansen, Sandra Burri Gram

    2016-01-01

    This paper presents the initial steps towards a collaboration-based method for persuasive design – the EDIE method (Explore, Design, Implement, Evaluate). The method is inspired by Design-Based Research, but developed to combine different design approaches that have dominated the persuasive...... technology field over the past decade. The rhetorical notion of Kairos is considered a key element in the EDIE method, resulting in a distinct focus on participatory design and constructive ethics. The method is explained through a practical example of developing persuasive learning designs in collaboration...

  13. JST Thesaurus Headwords and Synonyms: EDI [MeCab user dictionary for science technology term[Archive

    Full Text Available MeCab user dictionary for science technology term EDI 名詞 一般 * * * * EDI【情報交換】 EDI イーディーアイ Thesaurus2015 200906091295492920 C EG01 UNKNOWN_1 EDI

  14. Landau-Zener-Stueckelberg interferometry

    Shevchenko, S.N., E-mail: sshevchenko@ilt.kharkov.u [B.Verkin Institute for Low Temperature Physics and Engineering, Kharkov (Ukraine); RIKEN Advanced Science Institute, Wako-shi, Saitama (Japan); Ashhab, S.; Nori, Franco [RIKEN Advanced Science Institute, Wako-shi, Saitama (Japan); Department of Physics, The University of Michigan, Ann Arbor, MI (United States)

    2010-07-15

    A transition between energy levels at an avoided crossing is known as a Landau-Zener transition. When a two-level system (TLS) is subject to periodic driving with sufficiently large amplitude, a sequence of transitions occurs. The phase accumulated between transitions (commonly known as the Stueckelberg phase) may result in constructive or destructive interference. Accordingly, the physical observables of the system exhibit periodic dependence on the various system parameters. This phenomenon is often referred to as Landau-Zener-Stueckelberg (LZS) interferometry. Phenomena related to LZS interferometry occur in a variety of physical systems. In particular, recent experiments on LZS interferometry in superconducting TLSs (qubits) have demonstrated the potential for using this kind of interferometry as an effective tool for obtaining the parameters characterizing the TLS as well as its interaction with the control fields and with the environment. Furthermore, strong driving could allow for fast and reliable control of the quantum system. Here we review recent experimental results on LZS interferometry, and we present related theory.

  15. Landau-Zener-Stueckelberg interferometry

    Shevchenko, S.N.; Ashhab, S.; Nori, Franco

    2010-01-01

    A transition between energy levels at an avoided crossing is known as a Landau-Zener transition. When a two-level system (TLS) is subject to periodic driving with sufficiently large amplitude, a sequence of transitions occurs. The phase accumulated between transitions (commonly known as the Stueckelberg phase) may result in constructive or destructive interference. Accordingly, the physical observables of the system exhibit periodic dependence on the various system parameters. This phenomenon is often referred to as Landau-Zener-Stueckelberg (LZS) interferometry. Phenomena related to LZS interferometry occur in a variety of physical systems. In particular, recent experiments on LZS interferometry in superconducting TLSs (qubits) have demonstrated the potential for using this kind of interferometry as an effective tool for obtaining the parameters characterizing the TLS as well as its interaction with the control fields and with the environment. Furthermore, strong driving could allow for fast and reliable control of the quantum system. Here we review recent experimental results on LZS interferometry, and we present related theory.

  16. Numerical simulation of the electrodeionization (EDI) process accounting for water dissociation

    Lu Jun; Wang Yuxin; Zhu Jia

    2010-01-01

    The electrodeionization process (EDI) is usually operated at overlimiting current density, and is thus characterized by water dissociation and concentration polarization. We attempt to study the useful and harmful effects of water dissociation on the EDI process. A numerical steady state model was established to simulate the process of EDI, accounting for the effects of water dissociation. The differences in concentration polarization of membranes were investigated to study the effects of water dissociation on cation and anion membranes. Protons produced by water dissociation caused the resin to transform into the H-form. The H-form resin, which has high conductivity and high transport number, depletes protons in the interstitial solution. This explains the experimentally detected phenomenon that at high current densities, the pH value of the effluency of the dilute compartment (DC) stops decreasing when current increases. We suggest that the useful role of water dissociation in EDI is due to the H-form resin bringing more salt cations of the interstitial solution into the resin phase, thus producing a high conductivity channel for the electro-migration of the salt cations. This mechanism avoids the decrease in salt ion conductivity brought about by concentration polarization. The disadvantageous effect of concentration polarization on the transportation of salt ions in interstitial solution is thus lessened. An intermediate point between the useful and harmful effects of water dissociation was determined by the dependence of current efficiency and removal rate for both cations and anions as a function of current density.

  17. Identification of Disciplines and Fields. Edis Task I Report, Work Unit 1.4.

    Howard Research Co., Arlington, VA.

    This report presents the identification and definitions of subject oriented engineering and scientific disciplines and fields which are included in the EDIS Subject Categories. The discussion is extended to include the mix of subjects with other orientations, such as Item, Mission-Project, Expertise and Data Bank Categories. Sample queries are…

  18. Validation of Multilevel Constructs: Validation Methods and Empirical Findings for the EDI

    Forer, Barry; Zumbo, Bruno D.

    2011-01-01

    The purposes of this paper are to highlight the foundations of multilevel construct validation, describe two methodological approaches and associated analytic techniques, and then apply these approaches and techniques to the multilevel construct validation of a widely-used school readiness measure called the Early Development Instrument (EDI;…

  19. Kaon interferometry; Interferometria de kaons

    Roldao, C.G.; Padula, S.S. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil)

    1994-06-01

    Preliminary results of the {chi}{sup 2} analysis where data on kaon interferometry, obtained from the E859 Collaboration of the AGS/Brookhaven Nat.Lab., are compared with results of a hadronic resonance production model are presented. The main goal is to test the resolution power of the method here discussed when applied to the two-dimensional kaon interferometry. 11 refs., 2 figs.; e-mail: roldao at axp.ift.unesp.br; padula at axp.ift.unesp.br.

  20. Phase estimation in optical interferometry

    Rastogi, Pramod

    2014-01-01

    Phase Estimation in Optical Interferometry covers the essentials of phase-stepping algorithms used in interferometry and pseudointerferometric techniques. It presents the basic concepts and mathematics needed for understanding the phase estimation methods in use today. The first four chapters focus on phase retrieval from image transforms using a single frame. The next several chapters examine the local environment of a fringe pattern, give a broad picture of the phase estimation approach based on local polynomial phase modeling, cover temporal high-resolution phase evaluation methods, and pre

  1. From master slave interferometry to complex master slave interferometry: theoretical work

    Rivet, Sylvain; Bradu, Adrian; Maria, Michael; Feuchter, Thomas; Leick, Lasse; Podoleanu, Adrian

    2018-03-01

    A general theoretical framework is described to obtain the advantages and the drawbacks of two novel Fourier Domain Optical Coherence Tomography (OCT) methods denoted as Master/Slave Interferometry (MSI) and its extension denoted as Complex Master/Slave Interferometry (CMSI). Instead of linearizing the digital data representing the channeled spectrum before a Fourier transform can be applied to it (as in OCT standard methods), channeled spectrum is decomposed on the basis of local oscillations. This replaces the need for linearization, generally time consuming, before any calculation of the depth profile in the range of interest. In this model two functions, g and h, are introduced. The function g describes the modulation chirp of the channeled spectrum signal due to nonlinearities in the decoding process from wavenumber to time. The function h describes the dispersion in the interferometer. The utilization of these two functions brings two major improvements to previous implementations of the MSI method. The paper details the steps to obtain the functions g and h, and represents the CMSI in a matrix formulation that enables to implement easily this method in LabVIEW by using parallel programming with multi-cores.

  2. Complete positivity and neutron interferometry

    Benatti, F.; Floreanini, R.

    1999-01-01

    We analyze the dynamics of neutron beams in interferometry experiments using quantum dynamical semigroups. We show that these experiments could provide stringent limits on the non-standard, dissipative terms appearing in the extended evolution equations. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. EdiPy: a resource to simulate the evolution of plant mitochondrial genes under the RNA editing.

    Picardi, Ernesto; Quagliariello, Carla

    2006-02-01

    EdiPy is an online resource appropriately designed to simulate the evolution of plant mitochondrial genes in a biologically realistic fashion. EdiPy takes into account the presence of sites subjected to RNA editing and provides multiple artificial alignments corresponding to both genomic and cDNA sequences. Each artificial data set can successively be submitted to main and widespread evolutionary and phylogenetic software packages such as PAUP, Phyml, PAML and Phylip. As an online bioinformatic resource, EdiPy is available at the following web page: http://biologia.unical.it/py_script/index.html.

  4. Ediţii ale Clasificării Zecimale Dewey

    Zenovia Niculescu

    2009-01-01

    Full Text Available Studiul abordează evoluţia ediţiilor C.Z.D. din perspective actualizării terminologiei, realocărilor şi extinderii structurii principale şi auxiliare a limbajului de indexare Dewey. Analiza comparativă a ediţiilor C.Z.D. reflectă amplificarea şi eficientizarea schemei Dewey din punct de vedere al îmbunătăţirii ofertei informaţionale, prin indici de bază revizuiţi şi dezvoltaţi, precum şi a valorizării notaţiilor auxiliare.

  5. Choroidal Thickness Analysis in Patients with Usher Syndrome Type 2 Using EDI OCT

    Colombo, L.; Sala, B.; Montesano, G.; Pierrottet, C.; De Cillà, S.; Maltese, P.; Bertelli, M.; Rossetti, L.

    2015-01-01

    To portray Usher Syndrome type 2, analyzing choroidal thickness and comparing data reported in published literature on RP and healthy subjects. Methods. 20 eyes of 10 patients with clinical signs and genetic diagnosis of Usher Syndrome type 2. Each patient underwent a complete ophthalmologic examination including Best Corrected Visual Acuity (BCVA), intraocular pressure (IOP), axial length (AL), automated visual field (VF), and EDI OCT. Both retinal and choroidal measures were measured. Stati...

  6. DOD Electronic Commerce (EC)/Electronic Data Interchange (EDI) in contracting report

    1993-12-01

    Use of Electronic Commerce (EC)/Electronic Data Interchange (EDI) to support Department of Defense (DoD) procurement processes has been under consideration for some time. A 1988 Deputy Secretary of Defense memo calls for maximum use of EDI, based on 10 years of DoD EDI investigation and experiments. In 1990, Defense Management Review Decision 941 stated, 'The strategic goal of DoD's current efforts is to provide the department with the capability to initiate, conduct, and maintain its external business related transactions and internal logistics, contracting, and financial activities without requiring the use of hard copy media.' The EC in Contracting PAT membership reflected a broad cross section of Military Services and Defense Agencies working on a full-time basis for 60 days. The diversity of the EC in Contracting PAT ensured that the needs and concerns of all DoD components were addressed during the creation of the report. The resultant plan, therefore, represents a comprehensive approach for implementing EC throughout the DoD.

  7. Precision Geodesy via Radio Interferometry.

    Hinteregger, H F; Shapiro, I I; Robertson, D S; Knight, C A; Ergas, R A; Whitney, A R; Rogers, A E; Moran, J M; Clark, T A; Burke, B F

    1972-10-27

    Very-long-baseline interferometry experiments, involving observations of extragalactic radio sources, were performed in 1969 to determine the vector separations between antenna sites in Massachusetts and West Virginia. The 845.130-kilometer baseline was estimated from two separate experiments. The results agreed with each other to within 2 meters in all three components and with a special geodetic survey to within 2 meters in length; the differences in baseline direction as determined by the survey and by interferometry corresponded to discrepancies of about 5 meters. The experiments also yielded positions for nine extragalactic radio sources, most to within 1 arc second, and allowed the hydrogen maser clocks at the two sites to be synchronized a posteriori with an uncertainty of only a few nanoseconds.

  8. Holographic interferometry in construction analysis

    Hartikainen, T.

    1995-12-31

    In this work techniques for visualizing phase and opaque objects by ruby laser interferometry are introduced. A leakage flow as a phase object is studied by holographic interferometry and the intensity distribution of the interferograms presenting the leakage flow are computer-simulated. A qualitative and quantitative analysis of the leakage flow is made. The analysis is based on the experimental and theoretical results presented in this work. The holographic setup and the double pass method for visualizing leakage flow are explained. A vibrating iron plate is the opaque object. Transient impact waves are generated by a pistol bullet on the iron plate and visualized by holographic interferometry. An apparatus with the capability of detecting and calculating the delays necessary for laser triggering is introduced. A time series of interferograms presenting elastic wave formation in an iron plate is shown. A computer-simulation of the intensity distributions of these interferograms is made. An analysis based on the computer-simulation and the experimental data of the transient elastic wave is carried out and the results are presented. (author)

  9. Holographic interferometry of high pressure

    McIlwain, M.E.

    1987-01-01

    Measurements in turbulent flows have been historically performed using various types of probes and optical diagnostic methods. In general, probes suffer from plasma perturbation effects and are single point determination methods. Optical methods appear to be better suited to determinations in turbulent flows, however interpretation of the resulting data can often be complex. Methods such as laser Doppler anemometry, which relies on entrained particles, suffers from the fact that particles small enough to be swept along by the plasma are usually melted or sublimed in the plasma. Light refraction or diffraction methods such as shadow photography, interferometry, and holography have also been used to observe plasma flows. These methods typically suffer from the difficulty of interpreting line of sight images and obtaining quantitative data. A new method based on multi-pass holographic interferometry will be discussed. This method has certain advantages which can significantly simplify the complexity of line of sight interferometry image deconvolution. When the method employs high speed cinematography, time resolved images of the plasma flow can be obtained. This method has been applied to both transferred and non-transferred arcs and various types of DC-plasma torch produced jets. These studies and conclusions as to the usefulness of the technique are presented

  10. Investigation of the effect of heated ethanol fuel on combustion and emissions of an ethanol direct injection plus gasoline port injection (EDI + GPI) engine

    Huang, Yuhan; Hong, Guang

    2016-01-01

    Highlights: • Effect of EDI heating on the EDI + GPI engine performance was investigated. • CO and HC were significantly reduced and NO was slightly increased by EDI heating. • IMEP and combustion speed were slightly reduced by EDI heating. • EDI heating is effective to address the evaporation and over-cooling issues of EDI + GPI engine. - Abstract: Ethanol direct injection plus gasoline port injection (EDI + GPI) is a new technology to utilise ethanol fuel more efficiently and flexibly in spark ignition engines. One issue needs to be addressed in the development of EDI + GPI is the ethanol fuel’s low vapour pressure and large latent heat which slow down the ethanol’s evaporation and result in the mixture unready for combustion by the time of spark ignition and the consequent increase of CO and HC emissions. Heating the ethanol fuel to be directly injected (EDI heating) has been proposed to address this issue. This paper reports the investigation of the effect of EDI heating on the combustion and emissions of a research engine equipped with EDI + GPI. The results showed that EDI heating effectively reduced the CO and HC emissions of the engine due to the increase of evaporation rate and reduced fuel impingement and local over-cooling. The reduction of CO and HC became more significant with the increase of ethanol ratio. When the temperature of the ethanol fuel was increased by 40 °C, the CO and HC were reduced by as much as 43% and 51% respectively in EDI only condition at the original spark timing of 15 CAD BTDC, and 15% and 47% respectively at the minimum spark advance for best torque (MBT) timing of 19 CAD BTDC. On the other hand, the NO emission was slightly increased, but still much smaller than that in GPI only condition due to the strong cooling effect and low combustion temperature of EDI. The IMEP and combustion speed were slightly reduced by EDI heating due to the decrease of injector fuel flow rate and spray collapse of flash-boiling. The

  11. Attosecond electron wave packet interferometry

    Remetter, T.; Ruchon, T.; Johnsson, P.; Varju, K.; Gustafsson, E.

    2006-01-01

    Complete test of publication follows. The well controlled generation and characterization of attosecond XUV light pulses provide an unprecedented tool to study electron wave packets (EWPs). Here a train of attosecond pulses is used to create and study the phase of an EWP in momentum space. There is a clear analogy between electronic wave functions and optical fields. In optics, methods like SPIDER or wave front shearing interferometry, allow to measure the spectral or spatial phase of a light wave. These two methods are based on the same principle: an interferogram is produced when recombining two sheared replica of a light pulse, spectrally (SPIDER) or spatially (wave front shearing interferometry). This enables the comparison of two neighbouring different spectral or spatial slices of the original wave packet. In the experiment, a train of attosecond pulses is focused in an Argon atomic gas jet. EWPs are produced from the single XUV photon ionization of Argon atoms. If an IR beam is synchronized to the EWPs, it is possible to introduce a shear in momentum space between two consecutive s wave packets. A Velocity Map Imaging Spectrometer (VMIS) enables us to detect the interference pattern. An analysis of the interferograms will be presented leading to a conclusion about the symmetry of the studied wave packet.

  12. Direct Observations of ULF and Whistler-Mode Chorus Modulation of 500eV EDI Electrons by MMS

    Paulson, K. W.; Argall, M. R.; Ahmadi, N.; Torbert, R. B.; Le Contel, O.; Ergun, R.; Khotyaintsev, Y. V.; Strangeway, R. J.; Magnes, W.; Russell, C. T.

    2016-12-01

    We present here direct observations of chorus-wave modulated field-aligned 500 eV electrons using the Electron Drift Instrument (EDI) on board the Magnetospheric Multiscale mission. These periods of wave activity were additionally observed to be modulated by Pc5-frequency magnetic perturbations, some of which have been identified as drifting mirror-mode structures. The spacecraft encountered these mirror-mode structures just inside of the duskside magnetopause. Using the high sampling rate provided by EDI in burst sampling mode, we are able to observe the individual count fluctuations of field-aligned electrons in this region up to 512 Hz. We use the multiple look directions of EDI to generate both pitch angle and gyrophase plots of the fluctuating counts. Our observations often show unidirectional flow of these modulated electrons along the background field, and in some cases demonstrate gyrophase bunching in the wave region.

  13. Research-Based Teacher Education and Professional Development. Achievements and Contributions of EDiTE

    Rozalia Małgorzata Ligus

    2013-12-01

    Full Text Available This article’s aim is to describe some of the sources of the European debate over the third cycle studies in teacher education in Europe. Then it will introduce the international Project EDiTE as one of the collaborative initiatives concerning the European scientific proposal of the teachers’ lifelong learning development. Next, some good practices of promoting the doctoral research based teacher education on national levels will be presented. Finally, in the article, there will be revealed selected findings of the EDiTE team that are focused on the current needs in teacher education that have been pointed by different stakeholders of five European countries represented by the project consortium, while interviewing them in 2013 y. The main goal of this article is to involve the stakeholders in a thought provoking debate for future roles of teachers in Europe, but not through looking for a ‘standardized teacher model’ or to create a ‘European super teacher’, but to see the dilemmas that should be shared while questioning ‘What makes a teacher European?,’ as Michael Schratz underlines, in a diversity of national identities and in the face of challenges of 21st century.

  14. Conventional resin cation exchangers versus EDI for CACE measurement in power plants. Feasibility and practical field results

    Sigrist, Manuel [Swan Systeme AG, Hinwil (Switzerland)

    2017-10-15

    The conductivity measurement after a cation exchanger in power plants with steam turbines was introduced soon after 1950 by Larson and Lane. Due to the simple measuring principle, the sensitivity to ionic contaminations and to its high reliability, the conductivity measurement after a cation exchanger (CACE) has become the most commonly used online analytical method in power plants with steam generators. Swan has investigated electro deionisation (EDI) as substitution of the conventional cation exchange resin and has developed a new conductivity instrument using this principle. This paper provides a description of the conventional method for cation conductivity measurements as well as of the new AMI CACE using EDI method.

  15. Conventional resin cation exchangers versus EDI for CACE measurement in power plants. Feasibility and practical field results

    Sigrist, Manuel

    2017-01-01

    The conductivity measurement after a cation exchanger in power plants with steam turbines was introduced soon after 1950 by Larson and Lane. Due to the simple measuring principle, the sensitivity to ionic contaminations and to its high reliability, the conductivity measurement after a cation exchanger (CACE) has become the most commonly used online analytical method in power plants with steam generators. Swan has investigated electro deionisation (EDI) as substitution of the conventional cation exchange resin and has developed a new conductivity instrument using this principle. This paper provides a description of the conventional method for cation conductivity measurements as well as of the new AMI CACE using EDI method.

  16. Dispersion cancellation in a triple Laue interferometer

    Lemmel, Hartmut

    2014-01-01

    The concept of dispersion cancellation has been established in light optics to improve the resolution of interferometric measurements on dispersive media. Odd order dispersion cancellation allows to measure phase shifts without defocusing the interferometer due to wave packet displacements, while even order dispersion cancellation allows to measure time lags without losing resolution due to wave packet spreading. We report that either type of dispersion cancellation can be realized very easily in a triple Laue interferometer. Such interferometers are Mach–Zehnder interferometers based on Bragg diffraction, and are commonly used for neutrons and x-rays. Although the first x-ray interferometer was built nearly five decades ago, the feature of dispersion cancellation hasn't been recognized so far because the concept was hardly known in the neutron and x-ray community. However, it explains right away the surprising decoupling of phase shift and spatial displacement that we have discovered recently in neutron interferometry (Lemmel and Wagh 2010 Phys. Rev. A 82 033626). Furthermore, this article might inspire the light optics community to consider whether a triple Laue interferometer for laser light would be useful and feasible. We explain how dispersion cancellation works in neutron interferometry, and we describe the setup rigorously by solving the Schrödinger equation and by calculating the path integral. We point out, that the latter has to be evaluated with special care since in our setup the beam trajectory moves with respect to the crystal lattice of the interferometer. (paper)

  17. Analysis of Dream in Gholamhossein Sa'edi's Short Stories: A Model for Dream Analysis in Literary Works

    Veskari, Hassan; Pouralkhas, Shokrollah; Moharrami, Ramin; Ranjbar, Ebrahim

    2017-01-01

    Gholam Hussein Sa'edi is one of the greatest Iranian writers of short stories in the present era. Sa'edi's stories are based on the existence of fanciful and dreamlike settings in which he attempts to establish the endings of the stories to be the direct result of the characters' psychological reaction against their dreams. The linguistic and…

  18. Space Interferometry Mission Instrument Mechanical Layout

    Aaron, K.; Stubbs, D.; Kroening, K.

    2000-01-01

    The Space Interferometry Mission, planned for launch in 2006, will measure the positions of celestial objects to an unprecedented accuracy of 4x10 to the power of negative six arc (about 1 billionth of a degree).

  19. Some applications of holographic interferometry in biomechanics

    Ebbeni, Jean P. L.

    1992-03-01

    Holographic interferometry is well adapted for the determination of 2D strain fields in osseous structures. The knowledge of those strain fields is important for the understanding of structure behavior such as arthrosis.

  20. Interferometry of high energy nuclear collisions

    Padula, S.S.

    1990-01-01

    The interferometry is used for determining large space time dimensions of the Quark Gluon Plasma formed in high energy nuclear collisions or in high multiplicity fluctuations in p-barp collisions. (M.C.K.)

  1. Analytic approximations for inside-outside interferometry

    Padula, S.S.; Gyulassy, M. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)

    1990-07-30

    Analytical expressions for pion interferometry are derived illustrating the competing effects of various non-ideal aspects of inside-outside cascade dynamics at energies {proportional to}200 AGeV. (orig.).

  2. High-contrast Nulling Interferometry Techniques Project

    National Aeronautics and Space Administration — "We are developing rotating-baseline nulling-interferometry techniques and algorithms on the single-aperture Hale and Keck telescopes at near-infrared wavelengths,...

  3. Fundamental physics research and neutron interferometry

    Ioffe, A. [Hahn-Meitner-Institut Berlin GmbH (Germany)

    1996-08-01

    The possibility of the use of an extremely sensitive neutron interferometry technique for the study of electromagnetic structure of the neutron and the parity non-conservative effects in neutron spin rotation is discussed. (author)

  4. Novel Polarimetric SAR Interferometry Algorithms, Phase I

    National Aeronautics and Space Administration — Polarimetric radar interferometry (PolInSAR) is a new SAR imaging mode that is rapidly becoming an important technique for bare earth topographic mapping, tree...

  5. Mining inter-organizational business process models from EDI messages : a case study from the automotive sector

    Engel, R.; Aalst, van der W.M.P.; Zapletal, M.; Pichler, C.; Werthner, H.; Ralyté, J.; Franch, X.; Brinkkemper, S.; Wrycza, S.

    2012-01-01

    Traditional standards for Electronic Data Interchange (EDI), such as EDIFACT and ANSI X12, have been employed in Business-to-Business (B2B) e-commerce for decades. Due to their wide industry coverage and long-standing establishment, they will presumably continue to play an important role for some

  6. Inter-Organizational Trust in EDI Adoption: The Case of Ford Motor Company and PBR Limited in Australia.

    Ratnasingam, Pauline

    2001-01-01

    This study examines behavioral dimensions of trading partner trust in EDI (electronic data interchange) adoption via a qualitative interpretative case study conducted between an automotive manufacturer (Ford Motor Company) in Australia and their first tier supplier, PBR Limited. Findings suggest that trust is important for cooperative long-term…

  7. 2. Interferometry and polarimetry. 2.1. Principle of interferometry and polarimetry

    Kawahata, Kazuo; Okajima, Shigeki

    2000-01-01

    Laser interferometry and polarimetry are useful diagnostics for measuring electron density and the internal magnetic field distribution in the plasma. In this section, principles of interferometry and polarimetry and their applications to plasma diagnostics on LHD (section 2.2) and JT-60 (section 2.3) are descried. (author)

  8. O Encheirídion de Epicteto: Edição Bilíngue

    Aldo Lopes Dinucci

    2012-02-01

    Full Text Available Edição bilíngue do Encheirídion de Epicteto, obra do aluno de Epicteto (55-135 e cidadão romano de origem grega Lúcio Flávio Arriano de Nicomédia (86-160. Tal tradução, produzida por Aldo Dinucci (doutor em filosofia pela PUC-RJ e professor associado do Departamento de Filosofia da UFS e Alfredo Julien (doutor em história pela USP e professor adjunto do Departamento de História da UFS, foi financiada pelo CNPq (edital MCT/CNPq 02/2009 - Ciências Humanas, Sociais e Sociais Aplicadas.

  9. Millisecond resolution electron fluxes from the Cluster satellites: Calibrated EDI ambient electron data

    Förster, Matthias; Rashev, Mikhail; Haaland, Stein

    2017-04-01

    The Electron Drift Instrument (EDI) onboard Cluster can measure 500 eV and 1 keV electron fluxes with high time resolution during passive operation phases in its Ambient Electron (AE) mode. Data from this mode is available in the Cluster Science Archive since October 2004 with a cadence of 16 Hz in the normal mode or 128 Hz for burst mode telemetry intervals. The fluxes are recorded at pitch angles of 0, 90, and 180 degrees. This paper describes the calibration and validation of these measurements. The high resolution AE data allow precise temporal and spatial diagnostics of magnetospheric boundaries and will be used for case studies and statistical studies of low energy electron fluxes in the near-Earth space. We show examples of applications.

  10. Drought severity in intensive agricultural areas by means of the EDI index

    Procházková, Petra; Chuchma, Filip; Středa, Tomáš

    2016-12-01

    The aim of this work was the evaluation of drought severity development in the Czech Republic for the period 1971-2015 by the means of the Effective Drought Index (EDI). Annual values of the EDI index were determined using the method of effective precipitation for 14 localities spread throughout the Czech Republic (Central Europe). The seven categories were created according to obtained index values for the drought conditions determination for years during the period 1971-2015 through the percentile method. The annual index values were compared with acquired 2nd, 15th, 45th, 55th, 85th and 98th percentiles. Both the years with precipitation unfavourable conditions: 1972, 1973, 1984, 1990, 1991, 1992, 1993 and 2015 and the years with precipitation favourable conditions: 1977, 1987, 1995, 2001, 2002 and 2010 were determined. Precipitation conditions in the growing season from 61st to 180th day of the year were also analysed. This evaluation was conducted during the period 1971-2015 through the ten-day index values which were compared with acquired 2nd, 15th, 45th, 55th, 85th and 98th percentiles. Dry growing seasons occurred in 1973, 1974, 1976 and 1993. Wet growing seasons occurred in 1987, 2006 and 2010. Trend analysis of annual index values was performed through the Mann-Kendall test. Highly statistically significant increasing linear trends (P < 0.01) were found for four localities (Uherský Ostroh, Vysoká, Znojmo-Oblekovice and Žatec); statistically significant increasing trends (P < 0.05) were found for three localities (Brno-Chrlice, Lednice and Lípa). Based on the extrapolation of the trend, a slightly higher effective precipitation can be expected during the year in a substantial part of the country. However, these findings do not necessarily mean an optimal supply of agricultural land with water. Precipitation exhibits considerable unevenness of distribution through time. Given the increasing evapotranspiration demands of the environment their

  11. Space beam combiner for long-baseline interferometry

    Lin, Yao; Bartos, Randall D.; Korechoff, Robert P.; Shaklan, Stuart B.

    1999-04-01

    An experimental beam combiner (BC) is being developed to support the space interferometry program at the JPL. The beam combine forms the part of an interferometer where star light collected by the sidestats or telescopes is brought together to produce white light fringes, and to provide wavefront tilt information via guiding spots and beam walk information via shear spots. The assembly and alignment of the BC has been completed. The characterization test were performed under laboratory conditions with an artificial star and optical delay line. Part of each input beam was used to perform star tracking. The white light interference fringes were obtained over the selected wavelength range from 450 nm to 850 nm. A least-square fit process was used to analyze the fringe initial phase, fringe visibilities and shift errors of the optical path difference in the delay line using the dispersed white-light fringes at different OPD positions.

  12. Theory of supervirtual refraction interferometry

    Bharadwaj, Pawan; Schuster, Gerard T.; Mallinson, Ian; Dai, Wei

    2012-01-01

    Inverting for the subsurface velocity distribution by refraction traveltime tomography is a well-accepted imaging method by both the exploration and earthquake seismology communities. A significant drawback, however, is that the recorded traces become noisier with increasing offset from the source position, and so accurate picking of traveltimes in far-offset traces is often prevented. To enhance the signal-to-noise ratio (SNR) of the far-offset traces, we present the theory of supervirtual refraction interferometry where the SNR of far-offset head-wave arrivals can be theoretically increased by a factor proportional to; here, N is the number of receiver or source positions associated with the recording and generation of the head-wave arrival. There are two steps to this methodology: correlation and summation of the data to generate traces with virtual head-wave arrivals, followed by the convolution of the data with the virtual traces to create traces with supervirtual head-wave arrivals. This method is valid for any medium that generates head-wave arrivals recorded by the geophones. Results with both synthetic traces and field data demonstrate the feasibility of this method. There are at least four significant benefits of supervirtual interferometry: (1) an enhanced SNR of far-offset traces so the first-arrival traveltimes of the noisy far-offset traces can be more reliably picked to extend the useful aperture of the data, (2) the SNR of head waves in a trace that arrive later than the first arrival can be enhanced for accurate traveltime picking and subsequent inversion by later-arrival traveltime tomography, (3) common receiver-pair gathers can be analysed to detect the presence of diving waves in the first arrivals, which can be used to assess the nature of the refracting boundary, and (4) the source statics term is eliminated in the correlation operations so that the timing of the virtual traces is independent of the source excitation time. This suggests the

  13. Transfer of Air Force technical procurement bid set data to small businesses, using CALS and EDI: Test report

    NONE

    1994-08-15

    This report documents a test transfer of three Air Force technical procurement bid sets to one large and twelve small businesses, using the Department of Defense (DoD) Continuous Acquisition and Life-cycle Support (CALS) and ANSI ASC X12 Electronic Data Interchange (EDI) standards. The main goal of the test was to evaluate the effectiveness of using CALS technical data within the context of the DoD`s EDI-based standard approach to electronic commerce in procurement, with particular emphasis on receipt and use of the data by small contractors. Air Force procurement data was provided by the Sacramento Air Logistics Center at McClellan Air Force Base; the manufacturing participants were selected from among McClellan`s ``Blue Ribbon`` contractors, located throughout the US. The test was sponsored by the Air Force CALS Test Network, headquartered at Wright-Patterson Air Force Base. The test successfully demonstrated the technical feasibility of including CALS MIL-R-28002 (Raster) engineering data in an EDI Specification/Technical Information transaction set (ANSI ASC X12 841) when issuing electronic requests for quotation to small businesses. In many cases, the data was complete enough for the contractor participant to feel comfortable generating a quote. Lessons learned from the test are being fed back to the CALS and EDI standards organizations, and to future implementors of CALS-EDI based acquisition or contracting systems, which require the transfer of technical information, such as engineering data, manufacturing process data, quality test data, and other product or process data, in the form of a CALS or other digital datafile.

  14. Spectral Interferometry with Electron Microscopes

    Talebi, Nahid

    2016-01-01

    Interference patterns are not only a defining characteristic of waves, but also have several applications; characterization of coherent processes and holography. Spatial holography with electron waves, has paved the way towards space-resolved characterization of magnetic domains and electrostatic potentials with angstrom spatial resolution. Another impetus in electron microscopy has been introduced by ultrafast electron microscopy which uses pulses of sub-picosecond durations for probing a laser induced excitation of the sample. However, attosecond temporal resolution has not yet been reported, merely due to the statistical distribution of arrival times of electrons at the sample, with respect to the laser time reference. This is however, the very time resolution which will be needed for performing time-frequency analysis. These difficulties are addressed here by proposing a new methodology to improve the synchronization between electron and optical excitations through introducing an efficient electron-driven photon source. We use focused transition radiation of the electron as a pump for the sample. Due to the nature of transition radiation, the process is coherent. This technique allows us to perform spectral interferometry with electron microscopes, with applications in retrieving the phase of electron-induced polarizations and reconstructing dynamics of the induced vector potential. PMID:27649932

  15. Parsimonious Refraction Interferometry and Tomography

    Hanafy, Sherif

    2017-02-04

    We present parsimonious refraction interferometry and tomography where a densely populated refraction data set can be obtained from two reciprocal and several infill shot gathers. The assumptions are that the refraction arrivals are head waves, and a pair of reciprocal shot gathers and several infill shot gathers are recorded over the line of interest. Refraction traveltimes from these shot gathers are picked and spawned into O(N2) virtual refraction traveltimes generated by N virtual sources, where N is the number of geophones in the 2D survey. The virtual traveltimes can be inverted to give the velocity tomogram. This enormous increase in the number of traveltime picks and associated rays, compared to the many fewer traveltimes from the reciprocal and infill shot gathers, allows for increased model resolution and a better condition number with the system of normal equations. A significant benefit is that the parsimonious survey and the associated traveltime picking is far less time consuming than that for a standard refraction survey with a dense distribution of sources.

  16. The Lindley paradox in optical interferometry

    Mauri, Camillo; Paris, Matteo G.A.

    2016-01-01

    The so-called Lindley paradox is a counterintuitive statistical effect where the Bayesian and frequentist approaches to hypothesis testing give radically different answers, depending on the choice of the prior distribution. In this paper we address the occurrence of the Lindley paradox in optical interferometry and discuss its implications for high-precision measurements. In particular, we focus on phase estimation by Mach–Zehnder interferometers and show how to mitigate the conflict between the two approaches by using suitable priors. - Highlights: • We address the occurence of Lindley paradox in interferometry and discuss its implications for high-precision measurements. • We show how to mitigate the conflict between Bayesian and frequentist approach to interferometry using suitable priors. • Our results apply to calibration of homodyne detectors for quantum tomography.

  17. A system for airborne SAR interferometry

    Madsen, Søren Nørvang; Skou, Niels; Granholm, Johan

    1996-01-01

    Interferometric synthetic aperture radar (INSAR) systems have already demonstrated that elevation maps can be generated rapidly with single pass airborne across-track interferometry systems (XTT), and satellite repeat track interferometry (RTT) techniques have been used to map both elevation...... and perturbations of the surface of the Earth. The Danish Center for Remote Sensing (DCRS) has experimented with airborne INSAR since 1993. Multiple track data are collected in a special mode in which the radar directly steers the aircraft which allows for very precise control of the flight path. Such data sets......) the status of the airborne interferometry activities at DCRS, including the present system configuration, recent results, and some scientific applications of the system....

  18. Samuel A. Werner Pioneer of Neutron Interferometry

    Klein, Anthony

    2005-01-01

    Full text: In 1975, Sam Werner and his collaborators on the staff of the Scientific Laboratory of the Ford Motor Company carried out one of the pioneering experiments in neutron interferometry at the 2MW University of Michigan research reactor. It was the famous COW Experiment on gravitationally induced quantum interference. Shortly thereafter he moved to the University of Missouri in Columbia, to set up a program of neutron scattering research, including neutron interferometry. In the 25 years until his retirement a large number of beautiful experiments have been performed by Sam, with his group, his numerous students and many international collaborators. The Interferometry and Coherence session at this conference has been organized in his honour and the collected papers presented by his friends, collaborators and former students form his Festschrift. (author)

  19. Soft x-ray interferometry

    1993-09-01

    The purpose of the soft x-ray interferometry workshop held at Lawrence Berkeley Laboratory was to discuss with the scientific community the proposed technical design of the soft x-ray Fourier-transform spectrometer being developed at the ALS. Different design strategies for the instrument's components were discussed, as well as detection methods, signal processing issues, and how to meet the manufacturing tolerances that are necessary for the instrument to achieve the desired levels of performance. Workshop participants were encouraged to report on their experiences in the field of Fourier transform spectroscopy. The ALS is developing a Fourier transform spectrometer that is intended to operate up to 100 eV. The motivation is solely improved resolution and not the throughput (Jaquinot) or multiplex (Fellgett) advantage, neither of which apply for the sources and detectors used in this spectral range. The proposed implementation of this is via a Mach-Zehnder geometry that has been (1) distorted from a square to a rhombus to get grazing incidence of a suitable angle for 100 eV and (2) provided with a mirror-motion system to make the path difference between the interfering beams tunable. The experiment consists of measuring the emergent light intensity (I(x)) as a function of the path difference (x). The resolving power of the system is limited by the amount of path difference obtainable that is 1 cm (one million half-waves at 200 angstrom wavelength) in the design thus allowing a resolving power of one million. The free spectral range of the system is limited by the closeness with which the function I(x) is sampled. It is proposed to illuminate a helium absorption cell with roughly 1%-band-width light from a monochromator thus allowing one hundred aliases without spectral overlap even for sampling of I(x) at one hundredth of the Nyquist frequency

  20. Global astrometry with the space interferometry mission

    Boden, A.; Unwin, S.; Shao, M.

    1997-01-01

    The prospects for global astrometric measurements with the space interferometry mission (SIM) are discussed. The SIM mission will perform four microarcsec astrometric measurements on objects as faint as 20 mag using the optical interferometry technique with a 10 m baseline. The SIM satellite will perform narrow angle astrometry and global astrometry by means of an astrometric grid. The sensitivities of the SIM global astrometric performance and the grid accuracy versus instrumental parameters and sky coverage schemes are reported on. The problems in finding suitable astrometric grid objects to support microarcsec astrometry, and related ground-based observation programs are discussed.

  1. Ultrafast and Doppler-free femtosecondoptical ranging based on dispersivefrequency-modulated interferometry.

    Xia, Haiyun; Zhang, Chunxi

    2010-03-01

    An ultrafast and Doppler-free optical ranging system based on dispersive frequency-modulated interferometry is demonstrated. The principle is similar to the conventional frequency-modulated continuous-wave interferometry where the range information is derived from the beat frequency between the object signal and the reference signal. However, a passive and static frequency scanning is performed based on the chromatic dispersion of a transform-limited femtosecond pulse in the time domain. We point out that the unbalanced dispersion introduced in the Mach-Zehnder interferometer can be optimized to eliminate the frequency chirp in the temporal interferograms pertaining to the third order dispersion of the all-fiber system, if the dynamic range being considered is small. Some negative factors, such as the polarization instability of the femtosecond pulse, the power fluctuation of the optical signal and the nonuniform gain spectrum of the erbium-doped fiber amplifier lead to an obvious envelope deformation of the temporal interferograms from the Gaussian shape. Thus a new data processing method is proposed to guarantee the range resolution. In the experiment, the vibration of a speaker is measured. A range resolution of 1.59 microm is achieved with an exposure time of 394 fs at a sampling rate of 48.6 MHz.

  2. Cold neutron interferometry and its application. 2. Coherency and cold neutron spin interferometry

    Achiwa, Norio; Ebisawa, Toru

    1998-03-01

    The second workshop entitled 'Interference studies and cold neutron spin interferometry' was held on 10 and 11 March 1998 at KUR (Kyoto University Research Reactor Institute, Kumatori). Cold neutron spin interferometry is a new field. So it is very important for its development to learn the studies of X-ray and neutron optics which are rapidly developing with long history. In the workshop, the issues related to interference were reviewed such as experimental studies on cold neutron spin interferometry, theoretical and experimental approach on tunneling time, interference experiments by neutrons and its application, interference studies using synchrotron radiation, topics on silicon interferometry and quantum measurement problem and cold neutron interference experiment related to quantum measurement problem. The 8 of the presented papers are indexed individually. (J.P.N.)

  3. Transfer of Air Force technical procurement bid set data to small businesses, using CALS and EDI. Summary report. Revision 1

    NONE

    1995-01-10

    This report provides a summary of the Air Force CALS Test Network (AFCTN) Test Report Transfer of Air Force Technical Procurement Bid Set Data to Small Businesses, Using CALS and EDI (AFCTN Test Report 94-034, UCRL-ID-118619). It represents a synthesis of the results, conclusions, and recommendations, as well as a more concise presentation of the issues and strategies as viewed from AFCTN`s perspective. This report documents a test transfer of three Air Force technical procurement bid sets to one large and twelve small businesses, using the Department of Defense (DoD) Continuous Acquisition and Life-cycle Support (CALS) and ANSI ASC X12 Electronic Data Interchange (EDI) standards. The main goal of the test was to evaluate the effectiveness of using CALS technical data within the context of the DoD`s EDI-based standard approach to electronic commerce in procurement, with particular emphasis on receipt and use of the data by small contractors. Air Force procurement data was provided by the Sacramento Air Logistics Center at McClellan Air Force Base; the manufacturing participants were selected from among McClellan`s {open_quote}Blue Ribbon{close_quote} contractors, located throughout the United States. The test was sponsored by the Air Force CALS Test Network, headquartered at Wright-Patterson Air Force Base. The test successfully demonstrated the technical feasibility of including CALS MIL-R-28002 (Raster) engineering data in an EDI Specification/Technical Information transaction set (ANSI ASC X12 841) when issuing electronic requests for quotation to small businesses. In many cases, the data was complete enough for the contractor participant to feel comfortable generating a quote.

  4. Calibrating MMS Electron Drift Instrument (EDI) Ambient Electron Flux Measurements and Characterizing 3D Electric Field Signatures of Magnetic Reconnection

    Shuster, J. R.; Torbert, R. B.; Vaith, H.; Argall, M. R.; Li, G.; Chen, L. J.; Ergun, R. E.; Lindqvist, P. A.; Marklund, G. T.; Khotyaintsev, Y. V.; Russell, C. T.; Magnes, W.; Le Contel, O.; Pollock, C. J.; Giles, B. L.

    2015-12-01

    The electron drift instruments (EDIs) onboard each MMS spacecraft are designed with large geometric factors (~0.01cm2 str) to facilitate detection of weak (~100 nA) electron beams fired and received by the two gun-detector units (GDUs) when EDI is in its "electric field mode" to determine the local electric and magnetic fields. A consequence of the large geometric factor is that "ambient mode" electron flux measurements (500 eV electrons having 0°, 90°, or 180° pitch angle) can vary depending on the orientation of the EDI instrument with respect to the magnetic field, a nonphysical effect that requires a correction. Here, we present determinations of the θ- and ø-dependent correction factors for the eight EDI GDUs, where θ (ø) is the polar (azimuthal) angle between the GDU symmetry axis and the local magnetic field direction, and compare the corrected fluxes with those measured by the fast plasma instrument (FPI). Using these corrected, high time resolution (~1,000 samples per second) ambient electron fluxes, combined with the unprecedentedly high resolution 3D electric field measurements taken by the spin-plane and axial double probes (SDP and ADP), we are equipped to accurately detect electron-scale current layers and electric field waves associated with the non-Maxwellian (anisotropic and agyrotropic) particle distribution functions predicted to exist in the reconnection diffusion region. We compare initial observations of the diffusion region with distributions and wave analysis from PIC simulations of asymmetric reconnection applicable for modeling reconnection at the Earth's magnetopause, where MMS will begin Science Phase 1 as of September 1, 2015.

  5. Choroidal Thickness Analysis in Patients with Usher Syndrome Type 2 Using EDI OCT.

    Colombo, L; Sala, B; Montesano, G; Pierrottet, C; De Cillà, S; Maltese, P; Bertelli, M; Rossetti, L

    2015-01-01

    To portray Usher Syndrome type 2, analyzing choroidal thickness and comparing data reported in published literature on RP and healthy subjects. Methods. 20 eyes of 10 patients with clinical signs and genetic diagnosis of Usher Syndrome type 2. Each patient underwent a complete ophthalmologic examination including Best Corrected Visual Acuity (BCVA), intraocular pressure (IOP), axial length (AL), automated visual field (VF), and EDI OCT. Both retinal and choroidal measures were measured. Statistical analysis was performed to correlate choroidal thickness with age, BCVA, IOP, AL, VF, and RT. Comparison with data about healthy people and nonsyndromic RP patients was performed. Results. Mean subfoveal choroidal thickness (SFCT) was 248.21 ± 79.88 microns. SFCT was statistically significant correlated with age (correlation coefficient -0.7248179, p patients (p = 0.2138). Conclusions. Our study demonstrated in vivo choroidal thickness reduction in patients with Usher Syndrome type 2. These data are important for the comprehension of mechanisms of disease and for the evaluation of therapeutic approaches.

  6. Plasma convection in the magnetotail lobes: statistical results from Cluster EDI measurements

    S. Haaland

    2008-08-01

    Full Text Available A major part of the plasma in the Earth's magnetotail is populated through transport of plasma from the solar wind via the magnetotail lobes. In this paper, we present a statistical study of plasma convection in the lobes for different directions of the interplanetary magnetic field and for different geomagnetic disturbance levels. The data set used in this study consists of roughly 340 000 one-minute vector measurements of the plasma convection from the Cluster Electron Drift Instrument (EDI obtained during the period February 2001 to June 2007. The results show that both convection magnitude and direction are largely controlled by the interplanetary magnetic field (IMF. For a southward IMF, there is a strong convection towards the central plasma sheet with convection velocities around 10 km s−1. During periods of northward IMF, the lobe convection is almost stagnant. A By dominated IMF causes a rotation of the convection patterns in the tail with an oppositely directed dawn-dusk component of the convection for the northern and southern lobe. Our results also show that there is an overall persistent duskward component, which is most likely a result of conductivity gradients in the footpoints of the magnetic field lines in the ionosphere.

  7. Choroidal Thickness Analysis in Patients with Usher Syndrome Type 2 Using EDI OCT

    L. Colombo

    2015-01-01

    Full Text Available To portray Usher Syndrome type 2, analyzing choroidal thickness and comparing data reported in published literature on RP and healthy subjects. Methods. 20 eyes of 10 patients with clinical signs and genetic diagnosis of Usher Syndrome type 2. Each patient underwent a complete ophthalmologic examination including Best Corrected Visual Acuity (BCVA, intraocular pressure (IOP, axial length (AL, automated visual field (VF, and EDI OCT. Both retinal and choroidal measures were measured. Statistical analysis was performed to correlate choroidal thickness with age, BCVA, IOP, AL, VF, and RT. Comparison with data about healthy people and nonsyndromic RP patients was performed. Results. Mean subfoveal choroidal thickness (SFCT was 248.21±79.88 microns. SFCT was statistically significant correlated with age (correlation coefficient −0.7248179, p<0.01. No statistically significant correlation was found between SFCT and BCVA, IOP, AL, VF, and RT. SFCT was reduced if compared to healthy subjects (p<0.01. No difference was found when compared to choroidal thickness from nonsyndromic RP patients (p=0.2138. Conclusions. Our study demonstrated in vivo choroidal thickness reduction in patients with Usher Syndrome type 2. These data are important for the comprehension of mechanisms of disease and for the evaluation of therapeutic approaches.

  8. Precision measurements with atom interferometry

    Schubert, Christian; Abend, Sven; Schlippert, Dennis; Ertmer, Wolfgang; Rasel, Ernst M.

    2017-04-01

    Interferometry with matter waves enables precise measurements of rotations, accelerations, and differential accelerations [1-5]. This is exploited for determining fundamental constants [2], in fundamental science as e.g. testing the universality of free fall [3], and is applied for gravimetry [4], and gravity gradiometry [2,5]. At the Institut für Quantenoptik in Hannover, different approaches are pursued. A large scale device is designed and currently being set up to investigate the gain in precision for gravimetry, gradiometry, and fundamental tests on large baselines [6]. For field applications, a compact and transportable device is being developed. Its key feature is an atom chip source providing a collimated high flux of atoms which is expected to mitigate systematic uncertainties [7,8]. The atom chip technology and miniaturization benefits from microgravity experiments in the drop tower in Bremen and sounding rocket experiments [8,9] which act as pathfinders for space borne operation [10]. This contribution will report about our recent results. The presented work is supported by the CRC 1227 DQ-mat, the CRC 1128 geo-Q, the RTG 1729, the QUEST-LFS, and by the German Space Agency (DLR) with funds provided by the Federal Ministry of Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under Grant No. DLR 50WM1552-1557. [1] P. Berg et al., Phys. Rev. Lett., 114, 063002, 2015; I. Dutta et al., Phys. Rev. Lett., 116, 183003, 2016. [2] J. B. Fixler et al., Science 315, 74 (2007); G. Rosi et al., Nature 510, 518, 2014. [3] D. Schlippert et al., Phys. Rev. Lett., 112, 203002, 2014. [4] A. Peters et al., Nature 400, 849, 1999; A. Louchet-Chauvet et al., New J. Phys. 13, 065026, 2011; C. Freier et al., J. of Phys.: Conf. Series 723, 012050, 2016. [5] J. M. McGuirk et al., Phys. Rev. A 65, 033608, 2002; P. Asenbaum et al., arXiv:1610.03832. [6] J. Hartwig et al., New J. Phys. 17, 035011, 2015. [7] H. Ahlers et al., Phys. Rev. Lett. 116, 173601

  9. A novel PSB-EDI system for high ammonia wastewater treatment, biomass production and nitrogen resource recovery: PSB system.

    Wang, Hangyao; Zhou, Qin; Zhang, Guangming; Yan, Guokai; Lu, Haifeng; Sun, Liyan

    A novel process coupling photosynthetic bacteria (PSB) with electrodeionization (EDI) treatment was proposed to treat high ammonia wastewater and recover bio-resources and nitrogen. The first stage (PSB treatment) was used to degrade organic pollutants and accumulate biomass, while the second stage (EDI) was for nitrogen removal and recovery. The first stage was the focus in this study. The results showed that using PSB to transform organic pollutants in wastewater into biomass was practical. PSB could acclimatize to wastewater with a chemical oxygen demand (COD) of 2,300 mg/L and an ammonia nitrogen (NH4(+)-N) concentration of 288-4,600 mg/L. The suitable pH was 6.0-9.0, the average COD removal reached 80%, and the biomass increased by an average of 9.16 times. The wastewater COD removal was independent of the NH4(+)-N concentration. Moreover, the PSB functioned effectively when the inoculum size was only 10 mg/L. The PSB-treated wastewater was then further handled in an EDI system. More than 90% of the NH4(+)-N was removed from the wastewater and condensed in the concentrate, which could be used to produce nitrogen fertilizer. In the whole system, the average NH4(+)-N removal was 94%, and the average NH4(+)-N condensing ratio was 10.0.

  10. Inter-instrument calibration using magnetic field data from Flux Gate Magnetometer (FGM) and Electron Drift Instrument (EDI) onboard Cluster

    Nakamura, R.; Plaschke, F.; Teubenbacher, R.; Giner, L.; Baumjohann, W.; Magnes, W.; Steller, M.; Torbert, R. B.; Vaith, H.; Chutter, M.; Fornaçon, K.-H.; Glassmeier, K.-H.; Carr, C.

    2013-07-01

    We compare the magnetic field data obtained from the Flux-Gate Magnetometer (FGM) and the magnetic field data deduced from the gyration time of electrons measured by the Electron Drift Instrument (EDI) onboard Cluster to determine the spin axis offset of the FGM measurements. Data are used from orbits with their apogees in the magnetotail, when the magnetic field magnitude was between about 20 nT and 500 nT. Offset determination with the EDI-FGM comparison method is of particular interest for these orbits, because no data from solar wind are available in such orbits to apply the usual calibration methods using the Alfvén waves. In this paper, we examine the effects of the different measurement conditions, such as direction of the magnetic field relative to the spin plane and field magnitude in determining the FGM spin-axis offset, and also take into account the time-of-flight offset of the EDI measurements. It is shown that the method works best when the magnetic field magnitude is less than about 128 nT and when the magnetic field is aligned near the spin-axis direction. A remaining spin-axis offset of about 0.4 ~ 0.6 nT was observed between July and October 2003. Using multi-point multi-instrument measurements by Cluster we further demonstrate the importance of the accurate determination of the spin-axis offset when estimating the magnetic field gradient.

  11. Interinstrument calibration using magnetic field data from the flux-gate magnetometer (FGM) and electron drift instrument (EDI) onboard Cluster

    Nakamura, R.; Plaschke, F.; Teubenbacher, R.; Giner, L.; Baumjohann, W.; Magnes, W.; Steller, M.; Torbert, R. B.; Vaith, H.; Chutter, M.; Fornaçon, K.-H.; Glassmeier, K.-H.; Carr, C.

    2014-01-01

    We compare the magnetic field data obtained from the flux-gate magnetometer (FGM) and the magnetic field data deduced from the gyration time of electrons measured by the electron drift instrument (EDI) onboard Cluster to determine the spin-axis offset of the FGM measurements. Data are used from orbits with their apogees in the magnetotail, when the magnetic field magnitude was between about 20 and 500 nT. Offset determination with the EDI-FGM comparison method is of particular interest for these orbits, because no data from solar wind are available in such orbits to apply the usual calibration methods using the Alfvén waves. In this paper, we examine the effects of the different measurement conditions, such as direction of the magnetic field relative to the spin plane and field magnitude in determining the FGM spin-axis offset, and also take into account the time-of-flight offset of the EDI measurements. It is shown that the method works best when the magnetic field magnitude is less than about 128 nT and when the magnetic field is aligned near the spin-axis direction. A remaining spin-axis offset of about 0.4 ∼ 0.6 nT was observed for Cluster 1 between July and October 2003. Using multipoint multi-instrument measurements by Cluster we further demonstrate the importance of the accurate determination of the spin-axis offset when estimating the magnetic field gradient.

  12. Green's function representations for seismic interferometry

    Wapenaar, C.P.A.; Fokkema, J.T.

    2006-01-01

    The term seismic interferometry refers to the principle of generating new seismic responses by crosscorrelating seismic observations at different receiver locations. The first version of this principle was derived by Claerbout (1968), who showed that the reflection response of a horizontally layered

  13. Basic radio interferometry for future lunar missions

    Aminaei, Amin; Klein Wolt, Marc; Chen, Linjie; Bronzwaer, Thomas; Pourshaghaghi, Hamid Reza; Bentum, Marinus Jan; Falcke, Heino

    2014-01-01

    In light of presently considered lunar missions, we investigate the feasibility of the basic radio interferometry (RIF) for lunar missions. We discuss the deployment of two-element radio interferometer on the Moon surface. With the first antenna element is envisaged to be placed on the lunar lander,

  14. Monitoring civil infrastructure using satellite radar interferometry

    Chang, L.

    2015-01-01

    Satellite radar interferometry (InSAR) is a precise and efficient technique to monitor deformation on Earth with millimeter precision. Most InSAR applications focus on geophysical phenomena, such as earthquakes, volcanoes, or subsidence. Monitoring civil infrastructure with InSAR is relatively new,

  15. 3D super-virtual refraction interferometry

    Lu, Kai; AlTheyab, Abdullah; Schuster, Gerard T.

    2014-01-01

    Super-virtual refraction interferometry enhances the signal-to-noise ratio of far-offset refractions. However, when applied to 3D cases, traditional 2D SVI suffers because the stationary positions of the source-receiver pairs might be any place

  16. Photopolymer for Optical Holography and Holographic Interferometry

    Květoň, M.; Lédl, Vít; Havránek, A.; Fiala, P.

    2010-01-01

    Roč. 295, č. 1 (2010), s. 107-113 ISSN 1022-1360 Institutional research plan: CEZ:AV0Z20430508 Keywords : holographic interferometry * holography * photopolymerization * recording material * refractive index Subject RIV: BH - Optics, Masers, Lasers http://onlinelibrary.wiley.com/doi/10.1002/masy.200900093/pdf

  17. Assisted editing od SensorML with EDI. A bottom-up scenario towards the definition of sensor profiles.

    Oggioni, Alessandro; Tagliolato, Paolo; Fugazza, Cristiano; Bastianini, Mauro; Pavesi, Fabio; Pepe, Monica; Menegon, Stefano; Basoni, Anna; Carrara, Paola

    2015-04-01

    Sensor observation systems for environmental data have become increasingly important in the last years. The EGU's Informatics in Oceanography and Ocean Science track stressed the importance of management tools and solutions for marine infrastructures. We think that full interoperability among sensor systems is still an open issue and that the solution to this involves providing appropriate metadata. Several open source applications implement the SWE specification and, particularly, the Sensor Observation Services (SOS) standard. These applications allow for the exchange of data and metadata in XML format between computer systems. However, there is a lack of metadata editing tools supporting end users in this activity. Generally speaking, it is hard for users to provide sensor metadata in the SensorML format without dedicated tools. In particular, such a tool should ease metadata editing by providing, for standard sensors, all the invariant information to be included in sensor metadata, thus allowing the user to concentrate on the metadata items that are related to the specific deployment. RITMARE, the Italian flagship project on marine research, envisages a subproject, SP7, for the set-up of the project's spatial data infrastructure. SP7 developed EDI, a general purpose, template-driven metadata editor that is composed of a backend web service and an HTML5/javascript client. EDI can be customized for managing the creation of generic metadata encoded as XML. Once tailored to a specific metadata format, EDI presents the users a web form with advanced auto completion and validation capabilities. In the case of sensor metadata (SensorML versions 1.0.1 and 2.0), the EDI client is instructed to send an "insert sensor" request to an SOS endpoint in order to save the metadata in an SOS server. In the first phase of project RITMARE, EDI has been used to simplify the creation from scratch of SensorML metadata by the involved researchers and data managers. An interesting by

  18. Hydrodynamic disperser

    Bulatov, A.I.; Chernov, V.S.; Prokopov, L.I.; Proselkov, Yu.M.; Tikhonov, Yu.P.

    1980-01-15

    A hydrodynamic disperser is suggested which contains a housing, slit nozzles installed on a circular base arranged opposite from each other, resonators secured opposite the nozzle and outlet sleeve. In order to improve the effectiveness of dispersion by throttling the flow, each resonator is made in the form of a crimped plate with crimpings that decrease in height in a direction towards the nozzle.

  19. Future Looks Bright for Interferometry

    2008-09-01

    First Light for the PRIMA instrument The PRIMA instrument [1] of the ESO Very Large Telescope Interferometer (VLTI) recently saw "first light" at its new home atop Cerro Paranal in Chile. When fully operational, PRIMA will boost the capabilities of the VLTI to see sources much fainter than any previous interferometers, and enable astrometric precision unmatched by any other existing astronomical facility. PRIMA will be a unique tool for the detection of exoplanets. First Light of the PRIMA Instrument ESO PR Photo 29a/08 Preparing for PRIMA "PRIMA is specifically designed to see if one star 'wobbles' to and fro because it is has unseen planetary companions", says instrument scientist Gerard van Belle. "This allows us to not only detect exoplanets, but to measure their mass." PRIMA's expected astrometric precision of tens of micro-arcseconds is unmatched by any other existing astronomical facility, whether on the ground or in orbit [2]. In addition to taking astrometric measurements PRIMA will be the key to the imaging of faint sources with the VLTI using the science instruments AMBER and MIDI. Interferometry combines the light received by two or more telescopes, concentrating on tiny differences between the signals to measure angles with exquisite precision. Using this technique PRIMA can pick out details as sharply as a single telescope with a diameter equivalent to the largest distance between the telescopes. For the VLTI, the distance between the two telescope elements is about 200 metres. The PRIMA instrument is unique amongst the VLTI instruments, in that it is effectively two interferometers in one. PRIMA will take data from two sources on the sky simultaneously: the brighter source can be used for tracking, allowing the interferometer to "stare" at the fainter source for longer than is now possible with conventional interferometers. Although there have been earlier pathfinder experiments to test this technique, PRIMA represents the first facility

  20. Direct UV-Written Integrated Optical Beam Combiner for Stellar Interferometry

    Olivero, Massimo; Svalgaard, Mikael; Jocou, L.

    2007-01-01

    In this paper, we report the fabrication of an optical-beam combiner for stellar interferometry by means of direct ultraviolet (UV) writing. The component is shown to have good performance (fringe contrast > 95%, total loss similar to 0.7, -40-dB crosstalk, broadband operation covering at least...... the range 1.49-1.65 mu m, and low differential chromatic dispersion). The overall performance exceeds that of similar components currently used for astronomical research. This result, combined with the fast-prototyping ability of UV writing, opens up new possibilities for the realization of highly optimized...

  1. Dispersion Forces

    Buhmann, Stefan Yoshi

    2012-01-01

    In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

  2. Kinetic Titration Series with Biolayer Interferometry

    Frenzel, Daniel; Willbold, Dieter

    2014-01-01

    Biolayer interferometry is a method to analyze protein interactions in real-time. In this study, we illustrate the usefulness to quantitatively analyze high affinity protein ligand interactions employing a kinetic titration series for characterizing the interactions between two pairs of interaction patterns, in particular immunoglobulin G and protein G B1 as well as scFv IC16 and amyloid beta (1–42). Kinetic titration series are commonly used in surface plasmon resonance and involve sequential injections of analyte over a desired concentration range on a single ligand coated sensor chip without waiting for complete dissociation between the injections. We show that applying this method to biolayer interferometry is straightforward and i) circumvents problems in data evaluation caused by unavoidable sensor differences, ii) saves resources and iii) increases throughput if screening a multitude of different analyte/ligand combinations. PMID:25229647

  3. Optical interferometry for biology and medicine

    Nolte, David D

    2012-01-01

    This book presents the fundamental physics of optical interferometry as applied to biophysical, biological and medical research. Interference is at the core of many types of optical detection and is a powerful probe of cellular and tissue structure in interfererence microscopy and in optical coherence tomography. It is also the root cause of speckle and other imaging artefacts that limit range and resolution. For biosensor applications, the inherent sensitivity of interferometry enables ultrasensitive detection of molecules in biological samples for medical diagnostics. In this book, emphasis is placed on the physics of light scattering, beginning with the molecular origins of refraction as light propagates through matter, and then treating the stochastic nature of random fields that ultimately dominate optical imaging in cells and tissue. The physics of partial coherence plays a central role in the text, with a focus on coherence detection techniques that allow information to be selectively detected out of ...

  4. Permafrost Active Layer Seismic Interferometry Experiment (PALSIE).

    Abbott, Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knox, Hunter Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); James, Stephanie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Rebekah [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cole, Chris [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We present findings from a novel field experiment conducted at Poker Flat Research Range in Fairbanks, Alaska that was designed to monitor changes in active layer thickness in real time. Results are derived primarily from seismic data streaming from seven Nanometric Trillium Posthole seismometers directly buried in the upper section of the permafrost. The data were evaluated using two analysis methods: Horizontal to Vertical Spectral Ratio (HVSR) and ambient noise seismic interferometry. Results from the HVSR conclusively illustrated the method's effectiveness at determining the active layer's thickness with a single station. Investigations with the multi-station method (ambient noise seismic interferometry) are continuing at the University of Florida and have not yet conclusively determined active layer thickness changes. Further work continues with the Bureau of Land Management (BLM) to determine if the ground based measurements can constrain satellite imagery, which provide measurements on a much larger spatial scale.

  5. Enhanced Interferometry with Programmable Spatial Light Modulator

    2010-06-07

    Interferometry, Spatial Light Modulator, Surface Accuracy, Optics, Mirror, Zernike , Freeform Optics, Null Testing, Hartman, Wavefront 16. SECURITY...S L M P ix e l- c a m Tilted Flat Mirror L a s e r PV. ± 3.4 λ -Tilt by the flat mirror, ~7 waves ~ 14 fringes Interferogram 3D view (Various...Interferogram ( 3D view) x- profile y- profile (Various waveplates and telescopes not shown) SLM can compensate tilted wavefronts with an accuracy of

  6. Laser interferometry for the Big Bang Observer

    Harry, Gregory M.; Fritschel, Peter; Shaddock, Daniel A.; Folkner, William; Phinney, E. Sterl

    2006-01-01

    The Big Bang Observer is a proposed space-based gravitational-wave detector intended as a follow on mission to the Laser Interferometer Space Antenna (LISA). It is designed to detect the stochastic background of gravitational waves from the early universe. We discuss how the interferometry can be arranged between three spacecraft for this mission and what research and development on key technologies are necessary to realize this scheme.

  7. Laser interferometry for the Big Bang Observer

    Harry, Gregory M [LIGO Laboratory, Massachusetts Institute of Technology, NW17-161, Cambridge, MA 02139 (United States); Fritschel, Peter [LIGO Laboratory, Massachusetts Institute of Technology, NW17-161, Cambridge, MA 02139 (United States); Shaddock, Daniel A [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Folkner, William [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Phinney, E Sterl [California Institute of Technology, Pasadena, CA 91125 (United States)

    2006-08-07

    The Big Bang Observer is a proposed space-based gravitational-wave detector intended as a follow on mission to the Laser Interferometer Space Antenna (LISA). It is designed to detect the stochastic background of gravitational waves from the early universe. We discuss how the interferometry can be arranged between three spacecraft for this mission and what research and development on key technologies are necessary to realize this scheme.

  8. Interferometry and synthesis in radio astronomy

    Thompson, A Richard; Swenson Jr , George W

    2017-01-01

    This book is open access under a CC BY-NC 4.0 license. The third edition of this indispensable book in radio interferometry provides extensive updates to the second edition, including results and technical advances from the past decade; discussion of arrays that now span the full range of the radio part of the electromagnetic spectrum observable from the ground, 10 MHz to 1 THz; an analysis of factors that affect array speed; and an expanded discussion of digital signal-processing techniques and of scintillation phenomena and the effects of atmospheric water vapor on image distortion, among many other topics. With its comprehensiveness and detailed exposition of all aspects of the theory and practice of radio interferometry and synthesis imaging, this book has established itself as a standard reference in the field. It begins with an overview of the basic principles of radio astronomy, a short history of the development of radio interferometry, and an elementary discussion of the operation of an interferomete...

  9. Development of Speckle Interferometry Algorithm and System

    Shamsir, A. A. M.; Jafri, M. Z. M.; Lim, H. S.

    2011-01-01

    Electronic speckle pattern interferometry (ESPI) method is a wholefield, non destructive measurement method widely used in the industries such as detection of defects on metal bodies, detection of defects in intergrated circuits in digital electronics components and in the preservation of priceless artwork. In this research field, this method is widely used to develop algorithms and to develop a new laboratory setup for implementing the speckle pattern interferometry. In speckle interferometry, an optically rough test surface is illuminated with an expanded laser beam creating a laser speckle pattern in the space surrounding the illuminated region. The speckle pattern is optically mixed with a second coherent light field that is either another speckle pattern or a smooth light field. This produces an interferometric speckle pattern that will be detected by sensor to count the change of the speckle pattern due to force given. In this project, an experimental setup of ESPI is proposed to analyze a stainless steel plate using 632.8 nm (red) wavelength of lights.

  10. Comparing Laser Interferometry and Atom Interferometry Approaches to Space-Based Gravitational-Wave Measurement

    Baker, John; Thorpe, Ira

    2012-01-01

    Thoroughly studied classic space-based gravitational-wave missions concepts such as the Laser Interferometer Space Antenna (LISA) are based on laser-interferometry techniques. Ongoing developments in atom-interferometry techniques have spurred recently proposed alternative mission concepts. These different approaches can be understood on a common footing. We present an comparative analysis of how each type of instrument responds to some of the noise sources which may limiting gravitational-wave mission concepts. Sensitivity to laser frequency instability is essentially the same for either approach. Spacecraft acceleration reference stability sensitivities are different, allowing smaller spacecraft separations in the atom interferometry approach, but acceleration noise requirements are nonetheless similar. Each approach has distinct additional measurement noise issues.

  11. Numerical investigation to the dual-fuel spray combustion process in an ethanol direct injection plus gasoline port injection (EDI + GPI) engine

    Huang, Yuhan; Hong, Guang; Huang, Ronghua

    2015-01-01

    Highlights: • A 5D PDF table was used to model the dual-fuel turbulence–chemistry interactions. • The cooling effect of ethanol direct injection (EDI) was examined. • The higher flame speed of ethanol in EDI + GPI increased the thermal efficiency. • The partially premixed combustion in EDI + GPI reduced the combustion temperature. • Ethanol’s low evaporation rate in low temperature led to incomplete combustion. - Abstract: Ethanol direct injection plus gasoline port injection (EDI + GPI) is a new technology to make the use of ethanol fuel more effective and efficient in spark ignition engines. Multi-dimensional computational fluid dynamics modelling was conducted on an EDI + GPI engine in both single and dual fuelled conditions. The in-cylinder flow field was solved in the realizable k−ε turbulence model with detailed engine geometry. The temporal and spatial distributions of the liquid and vapour fuels were simulated with the spray breakup and evaporation models. The combustion process was modelled with the partially premixed combustion concept in which both mixture fraction and progress variable were solved. The three-dimensional and five-dimensional presumed Probability Density Function (PDF) look-up tables were used to model the single-fraction-mixture and two-fraction-mixture turbulence–chemistry interactions respectively. The model was verified by comparing the numerical and experimental results of spray pattern and cylinder pressure. The simulation results showed that the combustion process of EDI + GPI dual-fuelled condition was partially premixed combustion because of the low evaporation rate of ethanol spray in low temperature environment before combustion. Compared with GPI only, the higher flame speed of ethanol fuel contributed to the greater pressure rise rate and maximum cylinder pressure in EDI + GPI condition, which consequently resulted in higher power output and thermal efficiency. The lower adiabatic flame temperature of

  12. Livros do Brasil e a edição de romances brasileiros em Portugal nos anos 1940

    Thiago Mio Salla

    2017-12-01

    Full Text Available Enquanto esforço de historiografia literária e editorial, o presente artigo tem como objetivo lançar luz sobre as edições portuguesas de romances brasileiros realizadas pela editora Livros do Brasil, casa fundada em Lisboa, em 1944, por António de Sousa Pinto. A partir da recuperação de fontes primárias (com destaque para cartas e contratos, examinam-se, sobretudo, as negociações travadas entre Sousa Pinto e José Olympio no que diz respeito à edição, em Portugal, de títulos de dois importantes autores de nossa chamada geração de 1930: José Lins do Rego e Rachel de Queiroz. Mais especificamente, recupera-se o embate travado entre a atitude interventiva do editor luso, que defendia a necessidade de se ajustar o texto das obras de ambos os escritores à variante europeia do idioma, de modo a aproximá-las do leitorado português, e a recusa inicial dos romancistas, que exigiam o respeito estrito aos “brasileirismos” por eles empregados.

  13. Phase-shift interferometry with a digital photocamera

    Vannoni, Maurizio; Trivi, Marcelo; Molesini, Giuseppe

    2007-01-01

    A phase-shift interferometry experiment is proposed, working on a Twyman-Green optical configuration with additional polarization components. A guideline is provided to modern phase-shift interferometry, using concepts and laboratory equipment at the level of undergraduate optics courses

  14. Atom Interferometry for Fundamental Physics and Gravity Measurements in Space

    Kohel, James M.

    2012-01-01

    Laser-cooled atoms are used as freefall test masses. The gravitational acceleration on atoms is measured by atom-wave interferometry. The fundamental concept behind atom interferometry is the quantum mechanical particle-wave duality. One can exploit the wave-like nature of atoms to construct an atom interferometer based on matter waves analogous to laser interferometers.

  15. Chemical dispersants

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil

  16. Fast sub-electron detectors review for interferometry

    Feautrier, Philippe; Gach, Jean-Luc; Bério, Philippe

    2016-08-01

    New disruptive technologies are now emerging for detectors dedicated to interferometry. The detectors needed for this kind of applications need antonymic characteristics: the detector noise must be very low, especially when the signal is dispersed but at the same time must also sample the fast temporal characteristics of the signal. This paper describes the new fast low noise technologies that have been recently developed for interferometry and adaptive optics. The first technology is the Avalanche PhotoDiode (APD) infrared arrays made of HgCdTe. In this paper are presented the two programs that have been developed in that field: the Selex Saphira 320x256 [1] and the 320x255 RAPID detectors developed by Sofradir/CEA LETI in France [2], [3], [4]. Status of these two programs and future developments are presented. Sub-electron noise can now be achieved in the infrared using this technology. The exceptional characteristics of HgCdTe APDs are due to a nearly exclusive impaction ionization of the electrons, and this is why these devices have been called "electrons avalanche photodiodes" or e-APDs. These characteristics have inspired a large effort in developing focal plan arrays using HgCdTe APDs for low photon number applications such as active imaging in gated mode (2D) and/or with direct time of flight detection (3D imaging) and, more recently, passive imaging for infrared wave front correction and fringe tracking in astronomical observations. In addition, a commercial camera solution called C-RED, based on Selex Saphira and commercialized by First Light Imaging [5], is presented here. Some groups are also working with instruments in the visible. In that case, another disruptive technology is showing outstanding performances: the Electron Multiplying CCDs (EMCCD) developed mainly by e2v technologies in UK. The OCAM2 camera, commercialized by First Light Imaging [5], uses the 240x240 EMMCD from e2v and is successfully implemented on the VEGA instrument on the CHARA

  17. Probing dark energy with atom interferometry

    Burrage, Clare; Copeland, Edmund J.; Hinds, E.A.

    2015-01-01

    Theories of dark energy require a screening mechanism to explain why the associated scalar fields do not mediate observable long range fifth forces. The archetype of this is the chameleon field. Here we show that individual atoms are too small to screen the chameleon field inside a large high-vacuum chamber, and therefore can detect the field with high sensitivity. We derive new limits on the chameleon parameters from existing experiments, and show that most of the remaining chameleon parameter space is readily accessible using atom interferometry

  18. Probing dark energy with atom interferometry

    Burrage, Clare; Copeland, Edmund J. [School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Hinds, E.A., E-mail: Clare.Burrage@nottingham.ac.uk, E-mail: Edmund.Copeland@nottingham.ac.uk, E-mail: Ed.Hinds@imperial.ac.uk [Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

    2015-03-01

    Theories of dark energy require a screening mechanism to explain why the associated scalar fields do not mediate observable long range fifth forces. The archetype of this is the chameleon field. Here we show that individual atoms are too small to screen the chameleon field inside a large high-vacuum chamber, and therefore can detect the field with high sensitivity. We derive new limits on the chameleon parameters from existing experiments, and show that most of the remaining chameleon parameter space is readily accessible using atom interferometry.

  19. Baseline-dependent averaging in radio interferometry

    Wijnholds, S. J.; Willis, A. G.; Salvini, S.

    2018-05-01

    This paper presents a detailed analysis of the applicability and benefits of baseline-dependent averaging (BDA) in modern radio interferometers and in particular the Square Kilometre Array. We demonstrate that BDA does not affect the information content of the data other than a well-defined decorrelation loss for which closed form expressions are readily available. We verify these theoretical findings using simulations. We therefore conclude that BDA can be used reliably in modern radio interferometry allowing a reduction of visibility data volume (and hence processing costs for handling visibility data) by more than 80 per cent.

  20. Frequency scanning interferometry for CLIC component fiducialisation

    Kamugasa, Solomon William; Mainaud Durand, Helene; CERN. Geneva. ATS Department

    2016-01-01

    We present a strategy for the fiducialisation of CLIC’s Main Beam Quadrupole (MBQ) magnets using Frequency Scanning Interferometry (FSI). We have developed complementary device for a commercial FSI system to enable coordinate determination via multilateration. Using spherical high index glass retroreflectors with a wide acceptance angle, we optimise the geometry of measurement stations with respect to fiducials -- thus improving the precision of coordinates. We demonstrate through simulations that the 10 μm uncertainty required in the vertical and lateral axes for the fiducialisation of the MBQ can be attained using FSI multilateration.

  1. Balanced detection for self-mixing interferometry.

    Li, Kun; Cavedo, Federico; Pesatori, Alessandro; Zhao, Changming; Norgia, Michele

    2017-01-15

    We propose a new detection scheme for self-mixing interferometry using two photodiodes for implementing a differential acquisition. The method is based on the phase opposition of the self-mixing signal measured between the two laser diode facet outputs. The subtraction of the two outputs implements a sort of balanced detection that improves the signal quality, and allows canceling of unwanted signals due to laser modulation and disturbances on laser supply and transimpedance amplifier. Experimental results demonstrate the benefits of differential acquisition in a system for both absolute distance and displacement-vibration measurement. This Letter provides guidance for the design of self-mixing interferometers using balanced detection.

  2. Spin dynamics in polarized neutron interferometry

    Buchelt, R.J.

    2000-05-01

    Since its first implementation in 1974, perfect crystal neutron interferometry has become an extremely successful method applicable to a variety of research fields. Moreover, it proved as an illustrative and didactically valuable experiment for the demonstration of the fundamental principles of quantum mechanics, the neutron being an almost ideal probe for the detection of various effects, as it interacts by all four forces of nature. For instance, the first experimental verification of the 4-pi-periodicity of spinor wave functions was performed with perfect crystal neutron interferometry, and it remains the only method known which demonstrates the quantum mechanical wave-particle-duality of massive particles at a macroscopic separation of the coherent matter waves of several centimeters. A particular position is taken herein by polarized neutron interferometry, which as a collective term comprises all techniques and experiments which not only aim at the coherent splitting and macroscopic separation of neutron beams in the interferometer with the purpose of their separate treatment, but which aim to do so with explicit employment of the spin-magnetic properties of the neutron as a fermion. Remarkable aspects may arise, for example, if nuclear and magnetic potentials are concurrently applied to a partial beam of the interferometer: among other results, it is found that - in perfect agreement to the theoretical predictions - the neutron beam leaving the interferometer features non-zero polarization, even if the incident neutron beam, and hence either of the partial beams, is unpolarized. The main emphasis of the present work lies on the development of an appropriate formalism that describes the effect of simultaneous occurrence of nuclear and magnetic interaction on the emerging intensity and polarization for an arbitrary number of sequential magnetic regions, so-called domains. The confrontation with subtle theoretical problems was inevitable during the experimental

  3. Phase-conjugate resonant holographic interferometry applied to NH concentration measurements in a 2D diffusion flame

    Tzannis, A P; Beaud, P; Frey, H M; Gerber, T; Mischler, B; Radi, P P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Resonant Holographic Interferometry is a method based on the anomalous dispersion of light having a frequency close to an electronic transition of a molecule. We propose a novel single-laser, two-colour setup for recording resonant holograms and apply it to 2D species concentration measurements. The second colour is generated by optical phase-conjugation from Stimulated Brillouin scattering in a cell. Phase-Conjugate Resonant Holographic Interferometry (PCRHI) is demonstrated in a 2D NH{sub 3}/O{sub 2} flame yielding interferograms that contain information on the NH radical distribution in the flame. Experimental results are quantified by applying a numerical computation of the Voigt profiles. (author) 1 fig., 3 refs.

  4. Omnidirectional Internal Fixation by Double Approaches for Treating Rüedi-Allgöwer Type III Pilon Fractures.

    Dai, Chong-Hua; Sun, Jun; Chen, Kun-Quan; Zhang, Hui-Bo

    In the present study, we explored the effectiveness and complications of omnidirectional internal fixation using a double approach for treating Rüedi-Allgöwer type III pilon fractures. A retrospective analysis was performed of 19 cases of Rüedi-Allgöwer type III unilateral closed pilon fracture. With preoperative preparation and correct surgical timing, the reduction was performed using anteromedial and posterolateral approaches, and the fracture fragments were fixed by omnidirectional internal fixation. Imaging evaluation was performed using the Burwell-Charnley scoring system. The Johner-Wruhs scoring system was used to assess the functional status of the patients. A comprehensive evaluation of efficacy was performed using a 5-point Likert score. The complications were also recorded and analyzed. All patients were followed up for an average of 16.2 months. The operative incisions of 15 cases healed by primary intent and with delayed healing in 4. All patients had achieved bony union at an average of 16 weeks postoperatively. No deep infection, broken nail or withdrawn nail, exposed plate, or skin flap necrosis occurred. The Burwell-Charnley imaging evaluation showed that 14 patients had anatomic reduction of the articular surface and 5 had acceptable reduction. Using the Johner-Wruhs scoring system, the results were excellent for 8, good for 7, fair for 2, and poor for 2 patients; the combined rate of excellent and good results was 78.9%. The Likert score of efficacy self-reported by the patients was 3 to 4 points for 12 patients, 2 points for 4 patients, and 0 to 1 point for 3 patients. The Likert score of therapeutic efficacy reported by the physicians was 3 to 4 points for 10 patients, 2 points for 5 patients, and 0 to 1 point for 4 patients. Omnidirectional internal fixation using double approaches was an effective method to treat Rüedi-Allgöwer type III pilon fractures with satisfactory reduction and rigid fixation, good joint function recovery, and

  5. Persistent Scatterer Interferometry using Sentinel-1 Data

    Monserrat, Oriol; Crosetto, Michele; Devanthery, Nuria; Cuevas-Gonzalez, Maria; Qihuan, Huang; Barra, Anna; Crippa, Bruno

    2016-04-01

    This work will be focused on the deformation measurement and monitoring using SAR imagery from the C-band Sentinel-1, a space mission funded by the European Union and carried out by the European Space Agency (ESA) within the Copernicus Programme. The work will firstly address the data processing and analysis procedure implemented by the authors. This includes both Persistent Scatterer Interferometry (PSI) tools to analyse large stacks of SAR images (say, typically more than 20 images), and Differential SAR Interferometry (DInSAR) tools to analyse short SAR image stacks. The work will discuss the characteristics of the main products derived by using Sentinel-1 DInSAR and PSI: deformation maps, deformation velocity maps, deformation time series, residual topographic error, etc. The analysis will be carried out over different types of land use area, e.g. urban, peri-urban and rural areas. The deformation monitoring based on Sentinel-1 data will be compared with the monitoring based on data from pre-existing missions, e.g. C-band ERS and Envisat, X-band TerraSAR-X and CosmoSkyMed, etc. The comparison will concern different study areas, mainly located in Italy and Spain.

  6. Astronomical optical interferometry, II: Astrophysical results

    Jankov S.

    2011-01-01

    Full Text Available Optical interferometry is entering a new age with several ground- based long-baseline observatories now making observations of unprecedented spatial resolution. Based on a great leap forward in the quality and quantity of interferometric data, the astrophysical applications are not limited anymore to classical subjects, such as determination of fundamental properties of stars; namely, their effective temperatures, radii, luminosities and masses, but the present rapid development in this field allowed to move to a situation where optical interferometry is a general tool in studies of many astrophysical phenomena. Particularly, the advent of long-baseline interferometers making use of very large pupils has opened the way to faint objects science and first results on extragalactic objects have made it a reality. The first decade of XXI century is also remarkable for aperture synthesis in the visual and near-infrared wavelength regimes, which provided image reconstructions from stellar surfaces to Active Galactic Nuclei. Here I review the numerous astrophysical results obtained up to date, except for binary and multiple stars milliarcsecond astrometry, which should be a subject of an independent detailed review, taking into account its importance and expected results at microarcsecond precision level. To the results obtained with currently available interferometers, I associate the adopted instrumental settings in order to provide a guide for potential users concerning the appropriate instruments which can be used to obtain the desired astrophysical information.

  7. Observations of binary stars by speckle interferometry

    Morgan, B.L.; Beckmann, G.K.; Scaddan, R.J.

    1980-01-01

    This is the second paper in a series describing observations of binary stars using the technique of speckle interferometry. Observations were made using the 2.5-m Isaac Newton Telescope and the 1-m telescope of the Royal Greenwich Observatory and the 1.9-m telescope of the South African Astronomical Observatory. The classical Rayleigh diffraction limits are 0.050 arcsec for the 2.5-m telescope, 0.065 arcsec for the 1.9-m telescope and 0.125 arcsec for the 1-m telescope, at a wavelength of 500 nm. The results of 29 measurements of 26 objects are presented. The objects include long period spectroscopic binaries from the 6th Catalogue of Batten, close visual binary systems from the 3rd Catalogue of Finsen and Worley and variable stars. Nine of the objects have not been previously resolved by speckle interferometry. New members are detected in the systems β Cep, p Vel and iota UMa. (author)

  8. GLINT. Gravitational-wave laser INterferometry triangle

    Aria, Shafa; Azevedo, Rui; Burow, Rick; Cahill, Fiachra; Ducheckova, Lada; Holroyd, Alexa; Huarcaya, Victor; Järvelä, Emilia; Koßagk, Martin; Moeckel, Chris; Rodriguez, Ana; Royer, Fabien; Sypniewski, Richard; Vittori, Edoardo; Yttergren, Madeleine

    2017-11-01

    When the universe was roughly one billion years old, supermassive black holes (103-106 solar masses) already existed. The occurrence of supermassive black holes on such short time scales are poorly understood in terms of their physical or evolutionary processes. Our current understanding is limited by the lack of observational data due the limits of electromagnetic radiation. Gravitational waves as predicted by the theory of general relativity have provided us with the means to probe deeper into the history of the universe. During the ESA Alpach Summer School of 2015, a group of science and engineering students devised GLINT (Gravitational-wave Laser INterferometry Triangle), a space mission concept capable of measuring gravitational waves emitted by black holes that have formed at the early periods after the big bang. Morespecifically at redshifts of 15 big bang) in the frequency range 0.01 - 1 Hz. GLINT design strain sensitivity of 5× 10^{-24} 1/√ { {Hz}} will theoretically allow the study of early black holes formations as well as merging events and collapses. The laser interferometry, the technology used for measuring gravitational waves, monitors the separation of test masses in free-fall, where a change of separation indicates the passage of a gravitational wave. The test masses will be shielded from disturbing forces in a constellation of three geocentric orbiting satellites.

  9. Spaceborne intensity interferometry via spacecraft formation flight

    Ribak, Erez N.; Gurfil, Pini; Moreno, Coral

    2012-07-01

    Interferometry in space has marked advantages: long integration times and observation in spectral bands where the atmosphere is opaque. When installed on separate spacecraft, it also has extended and flexible baselines for better filling of the uv plane. Intensity interferometry has an additional advantage, being insensitive to telescope and path errors, but is unfortunately much less light-sensitive. In planning towards such a mission, we are experimenting with some fundamental research issues. Towards this end, we constructed a system of three vehicles floating on an air table in formation flight, with an autonomous orbit control. Each such device holds its own light collector, detector, and transmitter, to broadcast its intensity signal towards a central receiving station. At this station we implement parallel radio receivers, analogue to digital converters, and a digital three-way correlator. Current technology limits us to ~1GHz transmission frequency, which corresponds to a comfortable 0.3m accuracy in light-bucket shape and in its relative position. Naïve calculations place our limiting magnitude at ~7 in the blue and ultraviolet, where amplitude interferometers are limited. The correlation signal rides on top of this huge signal with its own Poisson noise, requiring a very large dynamic range, which needs to be transmitted in full. We are looking at open questions such as deployable optical collectors and radio antennae of similar size of a few meters, and how they might influence our data transmission and thus set our flux limit.

  10. Tulevast aastast alustab tööd elektrooniline andmevahetussüsteem EDI : piiriületus muutub kiiremaks / Margo Kokerov

    Kokerov, Margo, 1978-

    2001-01-01

    Eesti kaubaveo logistika elektroonilise andmevahetussüsteemi EDI (Electronic Data Interchange) projekti esimese etapina käivitub piiriületuse dokumentatsiooni ja kaubadeklaratsioonide elektroonilise esitamise võimalus. Toivo Jürgenson ja Jaan Pillesaar e-piiriületuse eelistest

  11. Isotope Analysis of Uranium by Interferometry; Analyse isotopique de l'uranium par interferometrie

    Leicknam, J P [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-07-01

    Among the optical methods which may be used to make isotopic measurements of {sup 235}U interferometry gives promising results. An apparatus is described which has a photomultiplier as receiver; the source must therefore have characteristics (intensity, stability, fineness of emitted rays) which have led to the use of electrode-less discharge tubes whose methods of production and excitation are given. An example of calibration is given. (author) [French] Parmi les methodes optiques permettant le dosage isotopique de l'uranium 235, l'interferometrie est une technique qui donne des resultats prometteurs. On decrit ici un appareil ayant un photo-multiplicateur comme recepteur; la source doit donc avoir des caracteristiques (intensite, stabilite, finesse des raies emises) qui ont conduit a utiliser des tubes a decharge sans electrode dont on indique la fabrication et le mode d'excitation. Un exemple d'etalonnage est enfin donne. (auteur)

  12. Resolving power test of 2-D K+ K+ interferometry

    Padula, Sandra S.; Roldao, Christiane G.

    1999-01-01

    Adopting a procedure previously proposed to quantitatively study pion interferometry 1 , an equivalent 2-D X 2 analysis was performed to test the resolving power of that method when applied to less favorable conditions, when no significant contribution from long lived resonances is expected, as in kaon interferometry. For that purpose, use is made of the preliminary E859 K + K + interferometry data from Si+Au collisions at 14.6 A GeV/c. Less sensitivity is achieved in the present case, although it is shown that it is still possible to distinguish two distinct decoupling geometries. (author)

  13. Generalized interferometry - I: theory for interstation correlations

    Fichtner, Andreas; Stehly, Laurent; Ermert, Laura; Boehm, Christian

    2017-02-01

    We develop a general theory for interferometry by correlation that (i) properly accounts for heterogeneously distributed sources of continuous or transient nature, (ii) fully incorporates any type of linear and nonlinear processing, such as one-bit normalization, spectral whitening and phase-weighted stacking, (iii) operates for any type of medium, including 3-D elastic, heterogeneous and attenuating media, (iv) enables the exploitation of complete correlation waveforms, including seemingly unphysical arrivals, and (v) unifies the earthquake-based two-station method and ambient noise correlations. Our central theme is not to equate interferometry with Green function retrieval, and to extract information directly from processed interstation correlations, regardless of their relation to the Green function. We demonstrate that processing transforms the actual wavefield sources and actual wave propagation physics into effective sources and effective wave propagation. This transformation is uniquely determined by the processing applied to the observed data, and can be easily computed. The effective forward model, that links effective sources and propagation to synthetic interstation correlations, may not be perfect. A forward modelling error, induced by processing, describes the extent to which processed correlations can actually be interpreted as proper correlations, that is, as resulting from some effective source and some effective wave propagation. The magnitude of the forward modelling error is controlled by the processing scheme and the temporal variability of the sources. Applying adjoint techniques to the effective forward model, we derive finite-frequency Fréchet kernels for the sources of the wavefield and Earth structure, that should be inverted jointly. The structure kernels depend on the sources of the wavefield and the processing scheme applied to the raw data. Therefore, both must be taken into account correctly in order to make accurate inferences on

  14. Advanced Differential Radar Interferometry (A-DInSAR) as integrative tool for a structural geological analysis

    Crippa, B.; Calcagni, L.; Rossi, G.; Sternai, P.

    2009-04-01

    Advanced Differential SAR interferometry (A-DInSAR) is a technique monitoring large-coverage surface deformations using a stack of interferograms generated from several complex SLC SAR images, acquired over the same target area at different times. In this work are described the results of a procedure to calculate terrain motion velocity on highly correlated pixels (E. Biescas, M. Crosetto, M. Agudo, O. Monserrat e B. Crippa: Two Radar Interferometric Approaches to Monitor Slow and Fast Land Deformation, 2007) in two area Gemona - Friuli, Northern Italy, Pollino - Calabria, Southern Italy, and, furthermore, are presented some consideration, based on successful examples of the present analysis. The choice of these pixels whose displacement velocity is calculated depends on the dispersion index value (DA) or using coherence values along the stack interferograms. A-DInSAR technique allows to obtain highly reliable velocity values of the vertical displacement. These values concern the movement of minimum surfaces of about 80m2 at the maximum resolution and the minimum velocity that can be recognized is of the order of mm/y. Because of the high versatility of the technology, because of the large dimensions of the area that can be analyzed (of about 10000Km2) and because of the high precision and reliability of the results obtained, we think it is possible to exploit radar interferometry to obtain some important information about the structural context of the studied area, otherwise very difficult to recognize. Therefore we propose radar interferometry as a valid investigation tool whose results must be considered as an important integration of the data collected in fieldworks.

  15. Multi-Axis Heterodyne Interferometry (MAHI)

    Thorpe, James

    The detection and measurement of gravitational waves represents humanity’s next, and final, opportunity to open an entirely new spectrum with which to view the universe. The first steps of this process will likely take place later this decade when the second-generation ground-based instruments such as Advanced LIGO approach design sensitivity. While these events will be historic, it will take a space-based detector to access the milliHertz gravitational wave frequency band, a band that is rich in both number and variety of sources. The Laser Interferometer Space Antenna (LISA) concept has been developed over the past two decades in the US and Europe to provide access to this band. The European Space Agency recently selected The Gravitational Universe as the science theme for the 3rd Large-class mission in the Cosmic Visions Programme, with the assumption that a LISA-like instrument would be implemented for launch in 2034. NASA has expressed interest in partnering on this effort and the US community has made its own judgment on the scientific potential of a space-based gravitational wave observatory through the selection of LISA as the 3rd flagship mission in the 2010 Decadal Survey. Much of the effort has been in retiring risk for the unique technologies that comprise a gravitational wave detector. A prime focus of this effort is LISA Pathfinder (LPF), a dedicated technology demonstrator mission led by ESA with contributions from NASA and several member states. LPF’s primary objective is to validate drag-free flight as an approach to realizing an inertial reference mass. Along the way, several important technologies will be demonstrated, including picometer-level heterodyne interferometry. However, there are several important differences between the interferometry design for LISA and that for LPF. These mostly result from the fact that LISA interferometry involves multiple lasers on separate spacecraft whereas LPF can use a single laser on a single spacecraft

  16. Atom-surface potentials and atom interferometry

    Babb, J.F.

    1998-01-01

    Long-range atom-surface potentials characterize the physics of many actual systems and are now measurable spectroscopically in deflection of atomic beams in cavities or in reflection of atoms in atomic fountains. For a ground state, spherically symmetric atom the potential varies as -1/R 3 near the wall, where R is the atom-surface distance. For asymptotically large distances the potential is weaker and goes as -1/R 4 due to retardation arising from the finite speed of light. This diminished interaction can also be interpreted as a Casimir effect. The possibility of measuring atom-surface potentials using atomic interferometry is explored. The particular cases studied are the interactions of a ground-state alkali-metal atom and a dielectric or a conducting wall. Accurate descriptions of atom-surface potentials in theories of evanescent-wave atomic mirrors and evanescent wave-guided atoms are also discussed. (author)

  17. Real time processor for array speckle interferometry

    Chin, G.; Florez, J.; Borelli, R.; Fong, W.; Miko, J.; Trujillo, C.

    1989-01-01

    With the construction of several new large aperture telescopes and the development of large format array detectors in the near IR, the ability to obtain diffraction limited seeing via IR array speckle interferometry offers a powerful tool. We are constructing a real-time processor to acquire image frames, perform array flat-fielding, execute a 64 x 64 element 2D complex FFT, and to average the power spectrum all within the 25 msec coherence time for speckles at near IR wavelength. The processor is a compact unit controlled by a PC with real time display and data storage capability. It provides the ability to optimize observations and obtain results on the telescope rather than waiting several weeks before the data can be analyzed and viewed with off-line methods

  18. Unification of nonclassicality measures in interferometry

    Yuan, Xiao; Zhou, Hongyi; Gu, Mile; Ma, Xiongfeng

    2018-01-01

    From an operational perspective, nonclassicality characterizes the exotic behavior in a physical process which cannot be explained with Newtonian physics. There are several widely used measures of nonclassicality, including coherence, discord, and entanglement, each proven to be essential resources in particular situations. There exists evidence of fundamental connections among the three measures. However, the sources of nonclassicality are still regarded differently and such connections are yet to be elucidated. Here, we introduce a general framework of defining a unified nonclassicality with an operational motivation founded on the capability of interferometry. Nonclassicality appears differently as coherence, discord, and entanglement in different scenarios with local measurement, weak basis-independent measurement, and strong basis-independent measurement, respectively. Our results elaborate how these three measures are related and how they can be transformed from each other. Experimental schemes are proposed to test the results.

  19. Compressed-sensing wavenumber-scanning interferometry

    Bai, Yulei; Zhou, Yanzhou; He, Zhaoshui; Ye, Shuangli; Dong, Bo; Xie, Shengli

    2018-01-01

    The Fourier transform (FT), the nonlinear least-squares algorithm (NLSA), and eigenvalue decomposition algorithm (EDA) are used to evaluate the phase field in depth-resolved wavenumber-scanning interferometry (DRWSI). However, because the wavenumber series of the laser's output is usually accompanied by nonlinearity and mode-hop, FT, NLSA, and EDA, which are only suitable for equidistant interference data, often lead to non-negligible phase errors. In this work, a compressed-sensing method for DRWSI (CS-DRWSI) is proposed to resolve this problem. By using the randomly spaced inverse Fourier matrix and solving the underdetermined equation in the wavenumber domain, CS-DRWSI determines the nonuniform sampling and spectral leakage of the interference spectrum. Furthermore, it can evaluate interference data without prior knowledge of the object. The experimental results show that CS-DRWSI improves the depth resolution and suppresses sidelobes. It can replace the FT as a standard algorithm for DRWSI.

  20. Edge effects in composites by moire interferometry

    Czarnek, R.; Post, D.; Herakovich, C.

    1983-01-01

    The very high sensitivity of moire interferometry has permitted the present edge effect experiments to be conducted at a low average stress and strain level, assuring linear and elastic behavior in the composite material samples tested. Sensitivity corresponding to 2450 line/mm moire was achieved with a 0.408 micron/fringe. Simultaneous observations of the specimen face and edge displacement fields showed good fringe definition despite the 1-mm thickness of the specimens and the high gradients, and it is noted that the use of a carrier pattern and optical filtering was effective in even these conditions. Edge effects and dramatic displacement gradients were confirmed in angle-ply composite laminates.

  1. The digital holographic interferometry in resonant acoustic spectroscopy

    GAPONOV, V.E.; AZAMATOV, Z.T.; REDKORECHEV, V.I.; ISAEV, A.M.

    2014-01-01

    The opportunities of application of digital holographic interferometry method for studies of shapes of resonant modes in resonant acoustic spectroscopy are shown. The results of experimental measurements and analytical calculations are submitted. (authors)

  2. Investigation of surface deformations by double exposure holographic interferometry

    Ecevit, F.N.; Guven, H.; Aydin, R.

    1990-01-01

    Surface deformations of rigid bodies produced by thermal as well as mechanical strains have been investigated using double-exposure holographic interferometry. The recorded interference fringes have been discussed qualitatively. (author). 9 refs, 4 figs

  3. Two-dimensional χ2 analysis in kaon interferometry

    Roldao, C.G.; Padula, S.S.

    1997-01-01

    This work presents preliminary results obtained from the χ 2 analysis performed on the E 859 Joint Work data. The work objective is to quantify the resolution power of the kaon two-dimension interferometry

  4. Observational Model for Precision Astrometry with the Space Interferometry Mission

    Turyshev, Slava G; Milman, Mark H

    2000-01-01

    The Space Interferometry Mission (SIM) is a space-based 10-m baseline Michelson optical interferometer operating in the visible waveband that is designed to achieve astrometric accuracy in the single digits of the microarcsecond domain...

  5. Dispersion strengthening

    Scattergood, R.O.; Das, E.S.P.

    1976-01-01

    Using digital computer-based methods, models for dispersion strengthening can now be developed which take into account many of the important effects that have been neglected in the past. In particular, the self interaction of a dislocation can be treated, and a computer simulation method was developed to determine the flow stress of a random distribution of circular, impenetrable obstacles, taking into account all such interactions. The flow stress values depended on the obstacle sizes and spacings, over and above the usual 1/L dependence where L is the average obstacle spacing. From an analysis of the results, it was found that the main effects of the self interactions can be captured in a line tension analogue in which the obstacles appear to be penetrable

  6. Hydrodynamic dispersion

    Pryce, M.H.L.

    1985-01-01

    A dominant mechanism contributing to hydrodynamic dispersion in fluid flow through rocks is variation of travel speeds within the channels carrying the fluid, whether these be interstices between grains, in granular rocks, or cracks in fractured crystalline rocks. The complex interconnections of the channels ensure a mixing of those parts of the fluid which travel more slowly and those which travel faster. On a macroscopic scale this can be treated statistically in terms of the distribution of times taken by a particle of fluid to move from one surface of constant hydraulic potential to another, lower, potential. The distributions in the individual channels are such that very long travel times make a very important contribution. Indeed, while the mean travel time is related to distance by a well-defined transport speed, the mean square is effectively infinite. This results in an asymmetrical plume which differs markedly from a gaussian shape. The distribution of microscopic travel times is related to the distribution of apertures in the interstices, or in the microcracks, which in turn are affected in a complex way by the stresses acting on the rock matrix

  7. High-latitude plasma convection during Northward IMF as derived from in-situ magnetospheric Cluster EDI measurements

    M. Förster

    2008-09-01

    Full Text Available In this study, we investigate statistical, systematic variations of the high-latitude convection cell structure during northward IMF. Using 1-min-averages of Cluster/EDI electron drift observations above the Northern and Southern polar cap areas for six and a half years (February 2001 till July 2007, and mapping the spatially distributed measurements to a common reference plane at ionospheric level in a magnetic latitude/MLT grid, we obtained regular drift patterns according to the various IMF conditions. We focus on the particular conditions during northward IMF, where lobe cells at magnetic latitudes >80° with opposite (sunward convection over the central polar cap are a permanent feature in addition to the main convection cells at lower latitudes. They are due to reconnection processes at the magnetopause boundary poleward of the cusp regions. Mapped EDI data have a particular good coverage within the central part of the polar cap, so that these patterns and their dependence on various solar wind conditions are well verified in a statistical sense. On average, 4-cell convection pattern are shown as regular structures during periods of nearly northward IMF with the tendency of a small shift toward negative clock angles. The positions of these high-latitude convection foci are within 79° to 85° magnetic latitude and 09:00–15:00 MLT. The MLT positions are approximately symmetric ±2 h about 11:30 MLT, i.e. slightly offset from midday toward prenoon hours, while the maximum (minimum potential of the high-latitude cells is at higher magnetic latitudes near their maximum potential difference at ≈−10° to −15° clock angle for the North (South Hemisphere. With increasing clock angle distances from ≈IMFBz+, a gradual transition occurs from the 4-cell pattern via a 3-cell to the common 2-cell convection pattern, in the course of which one of the medium-scale high-latitude dayside cells diminishes and disappears while the

  8. Frequency-Shifted Interferometry — A Versatile Fiber-Optic Sensing Technique

    Fei Ye

    2014-06-01

    Full Text Available Fiber-optic sensing is a field that is developing at a fast pace. Novel fiber-optic sensor designs and sensing principles constantly open doors for new opportunities. In this paper, we review a fiber-optic sensing technique developed in our research group called frequency-shifted interferometry (FSI. This technique uses a continuous-wave light source, an optical frequency shifter, and a slow detector. We discuss the operation principles of several FSI implementations and show their applications in fiber length and dispersion measurement, locating weak reflections along a fiber link, fiber-optic sensor multiplexing, and high-sensitivity cavity ring-down measurement. Detailed analysis of FSI system parameters is also presented.

  9. Using Seismic Interferometry to Investigate Seismic Swarms

    Matzel, E.; Morency, C.; Templeton, D. C.

    2017-12-01

    Seismicity provides a direct means of measuring the physical characteristics of active tectonic features such as fault zones. Hundreds of small earthquakes often occur along a fault during a seismic swarm. This seismicity helps define the tectonically active region. When processed using novel geophysical techniques, we can isolate the energy sensitive to the fault, itself. Here we focus on two methods of seismic interferometry, ambient noise correlation (ANC) and the virtual seismometer method (VSM). ANC is based on the observation that the Earth's background noise includes coherent energy, which can be recovered by observing over long time periods and allowing the incoherent energy to cancel out. The cross correlation of ambient noise between a pair of stations results in a waveform that is identical to the seismogram that would result if an impulsive source located at one of the stations was recorded at the other, the Green function (GF). The calculation of the GF is often stable after a few weeks of continuous data correlation, any perturbations to the GF after that point are directly related to changes in the subsurface and can be used for 4D monitoring.VSM is a style of seismic interferometry that provides fast, precise, high frequency estimates of the Green's function (GF) between earthquakes. VSM illuminates the subsurface precisely where the pressures are changing and has the potential to image the evolution of seismicity over time, including changes in the style of faulting. With hundreds of earthquakes, we can calculate thousands of waveforms. At the same time, VSM collapses the computational domain, often by 2-3 orders of magnitude. This allows us to do high frequency 3D modeling in the fault region. Using data from a swarm of earthquakes near the Salton Sea, we demonstrate the power of these techniques, illustrating our ability to scale from the far field, where sources are well separated, to the near field where their locations fall within each other

  10. Reduction of chromatic aberration influences in vertical scanning white-light interferometry

    Lehmann, Peter; Kühnhold, Peter; Xie, Weichang

    2014-01-01

    Vertical scanning white-light interferometry (SWLI) is a well-established method that is widely used in high precision surface topography measurement. However, SWLI results show characteristic slope-dependent errors due to dispersion effects and lateral chromatic aberrations of the optical imaging system. In this paper, we present methods to characterize these systematic errors related to dispersion and lateral colour. Lateral colour leads to field-dependent systematic discrepancies of the topography data obtained from the envelope position of a low-coherence interference signal and the data resulting from its interference phase. Hence, an erroneous fringe order obtained from the envelope position leads to a 2π phase jump and thus to a so-called ghost step in the measured topography. Our first approach to solve this problem is based on the measurement of a surface standard of well-known geometry. By comparison of measurement results related to the envelope position and the phase of SWLI signals, the systematic error is estimated and a numerical error compensation method is proposed. Both experimental and simulation results confirm the validity of this numerical method. In addition, using an improved design of a white-light Michelson interferometer we demonstrate experimentally that lateral chromatic aberrations and dispersion influences can be reduced also in a physical way. In this context, a conventional long working distance microscope objective is used which was not originally designed for a Michelson interference microscope. (paper)

  11. Interhemispheric differences and solar cycle effects of the high-latitude ionospheric convection patterns deduced from Cluster EDI observations

    Förster, Matthias; Haaland, Stein

    2015-04-01

    Here, we present a study of ionospheric convection at high latitudes that is based on satellite measurements of the Electron Drift Instrument (EDI) on-board the Cluster satellites, which were obtained over a full solar cycle (2001-2013). The mapped drift measurements are covering both hemispheres and a variety of different solar wind and interplanetary magnetic field (IMF) conditions. The large amount of data allows us to perform more detailed statistical studies. We show that flow patterns and polar cap potentials can differ between the two hemispheres on statistical average for a given IMF orientation. In particular, during southward directed IMF conditions, and thus enhanced energy input from the solar wind, we find that the southern polar cap has a higher cross polar cap potential. We also find persistent north-south asymmetries which cannot be explained by external drivers alone. Much of these asymmetries can probably be explained by significant differences in the strength and configuration of the geomagnetic field between the Northern and Southern Hemisphere. Since the ionosphere is magnetically connected to the magnetosphere, this difference will also be reflected in the magnetosphere in the form of different feedback from the two hemispheres. Consequently, local ionospheric conditions and the geomagnetic field configuration are important for north-south asymmetries in large regions of geospace. The average convection is higher during periods with high solar activity. Although local ionospheric conditions may play a role, we mainly attribute this to higher geomagnetic activity due to enhanced solar wind - magnetosphere interactions.

  12. Principles and methods of neutron interferometry

    Bonse, U.

    1978-01-01

    The merits of Angstrom range interferometry with neutrons are briefly outlined. The energy (wavelength) range which is accessible with the triple Laue case (LLL) crystal interferometer is estimated, assuming a neutron source with flux characteristics similar to that of the HFR at Grenoble. It appears that a range in E from roughly 2.3 meV to 8.2eV (lambda approximatly equal to 6A to 0.1A) can be covered with LLL interferometers manufactured with presently available perfect crystals of silicon. Within this range there exists a number of scattering resonances that it seems worth while to investigate interferometrically. The attainable resolution ΔE/E is estimated to be at least 10 -3 for E -2 above. The essentials of zero absorption Bragg diffraction optics of the neutron LLL interferometer are described. Virtues and weaknesses of different LLL geometries are discussed. The influence of geometrical abberrations, strain and position instabilities are surveyed. Aspects of coherent scattering length measurements and of neutron phase topography are discussed

  13. 3D super-virtual refraction interferometry

    Lu, Kai

    2014-08-05

    Super-virtual refraction interferometry enhances the signal-to-noise ratio of far-offset refractions. However, when applied to 3D cases, traditional 2D SVI suffers because the stationary positions of the source-receiver pairs might be any place along the recording plane, not just along a receiver line. Moreover, the effect of enhancing the SNR can be limited because of the limitations in the number of survey lines, irregular line geometries, and azimuthal range of arrivals. We have developed a 3D SVI method to overcome these problems. By integrating along the source or receiver lines, the cross-correlation or the convolution result of a trace pair with the source or receiver at the stationary position can be calculated without the requirement of knowing the stationary locations. In addition, the amplitudes of the cross-correlation and convolution results are largely strengthened by integration, which is helpful to further enhance the SNR. In this paper, both synthetic and field data examples are presented, demonstrating that the super-virtual refractions generated by our method have accurate traveltimes and much improved SNR.

  14. On marginally resolved objects in optical interferometry

    Lachaume, R.

    2003-03-01

    With the present and soon-to-be breakthrough of optical interferometry, countless objects shall be within reach of interferometers; yet, most of them are expected to remain only marginally resolved with hectometric baselines. In this paper, we tackle the problem of deriving the properties of a marginally resolved object from its optical visibilities. We show that they depend on the moments of flux distribution of the object: centre, mean angular size, asymmetry, and curtosis. We also point out that the visibility amplitude is a second-order phenomenon, whereas the phase is a combination of a first-order term, giving the location of the photocentre, and a third-order term, more difficult to detect than the visibility amplitude, giving an asymmetry coefficient of the object. We then demonstrate that optical visibilities are not a good model constraint while the object stays marginally resolved, unless observations are carried out at different wavelengths. Finally, we show an application of this formalism to circumstellar discs.

  15. High-Speed Interferometry Under Impacting Drops

    Langley, Kenneth R.; Li, Erqiang; Thoroddsen, Sigurdur T

    2017-01-01

    Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

  16. Time delay interferometry with moving spacecraft arrays

    Tinto, Massimo; Estabrook, F.B.; Armstrong, J.W.

    2004-01-01

    Space-borne interferometric gravitational wave detectors, sensitive in the low-frequency (millihertz) band, will fly in the next decade. In these detectors the spacecraft-to-spacecraft light-travel-times will necessarily be unequal, time varying, and (due to aberration) have different time delays on up and down links. The reduction of data from moving interferometric laser arrays in solar orbit will in fact encounter nonsymmetric up- and down-link light time differences that are about 100 times larger than has previously been recognized. The time-delay interferometry (TDI) technique uses knowledge of these delays to cancel the otherwise dominant laser phase noise and yields a variety of data combinations sensitive to gravitational waves. Under the assumption that the (different) up- and down-link time delays are constant, we derive the TDI expressions for those combinations that rely only on four interspacecraft phase measurements. We then turn to the general problem that encompasses time dependence of the light-travel times along the laser links. By introducing a set of noncommuting time-delay operators, we show that there exists a quite general procedure for deriving generalized TDI combinations that account for the effects of time dependence of the arms. By applying our approach we are able to re-derive the 'flex-free' expression for the unequal-arm Michelson combinations X 1 , and obtain the generalized expressions for the TDI combinations called relay, beacon, monitor, and symmetric Sagnac

  17. High-Speed Interferometry Under Impacting Drops

    Langley, Kenneth R.

    2017-08-31

    Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

  18. Bounding the Higgs boson width through interferometry.

    Dixon, Lance J; Li, Ye

    2013-09-13

    We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for gg→γγ. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson width at the Large Hadron Collider through "interferometry." We investigate how the shift depends on the Higgs width, in a model that maintains constant Higgs boson signal yields. At Higgs widths above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the width. The apparent mass shift could be measured by comparing with the ZZ* channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum.

  19. Experimental demonstration of deep frequency modulation interferometry.

    Isleif, Katharina-Sophie; Gerberding, Oliver; Schwarze, Thomas S; Mehmet, Moritz; Heinzel, Gerhard; Cervantes, Felipe Guzmán

    2016-01-25

    Experiments for space and ground-based gravitational wave detectors often require a large dynamic range interferometric position readout of test masses with 1 pm/√Hz precision over long time scales. Heterodyne interferometer schemes that achieve such precisions are available, but they require complex optical set-ups, limiting their scalability for multiple channels. This article presents the first experimental results on deep frequency modulation interferometry, a new technique that combines sinusoidal laser frequency modulation in unequal arm length interferometers with a non-linear fit algorithm. We have tested the technique in a Michelson and a Mach-Zehnder Interferometer topology, respectively, demonstrated continuous phase tracking of a moving mirror and achieved a performance equivalent to a displacement sensitivity of 250 pm/Hz at 1 mHz between the phase measurements of two photodetectors monitoring the same optical signal. By performing time series fitting of the extracted interference signals, we measured that the linearity of the laser frequency modulation is on the order of 2% for the laser source used.

  20. Quasar Astrophysics with the Space Interferometry Mission

    Unwin, Stephen; Wehrle, Ann; Meier, David; Jones, Dayton; Piner, Glenn

    2007-01-01

    Optical astrometry of quasars and active galaxies can provide key information on the spatial distribution and variability of emission in compact nuclei. The Space Interferometry Mission (SIM PlanetQuest) will have the sensitivity to measure a significant number of quasar positions at the microarcsecond level. SIM will be very sensitive to astrometric shifts for objects as faint as V = 19. A variety of AGN phenomena are expected to be visible to SIM on these scales, including time and spectral dependence in position offsets between accretion disk and jet emission. These represent unique data on the spatial distribution and time dependence of quasar emission. It will also probe the use of quasar nuclei as fundamental astrometric references. Comparisons between the time-dependent optical photocenter position and VLBI radio images will provide further insight into the jet emission mechanism. Observations will be tailored to each specific target and science question. SIM will be able to distinguish spatially between jet and accretion disk emission; and it can observe the cores of galaxies potentially harboring binary supermassive black holes resulting from mergers.

  1. Geometric phase modulation for stellar interferometry

    Roy, M.; Boschung, B.; Tango, W.J.; Davis, J.

    2002-01-01

    Full text: In a long baseline optical interferometer, the fringe visibility is normally measured by modulation of the optical path difference between the two arms of the instruments. To obtain accurate measurements, the spectral bandwidth must be narrow, limiting the sensitivity of the technique. The application of geometric phase modulation technique to stellar interferometry has been proposed by Tango and Davis. Modulation of the geometric phase has the potential for improving the sensitivity of optical interferometers, and specially the Sydney University Stellar Interferometer (SUSI), by allowing broad band modulation of the light signals. This is because a modulator that changes the geometric phase of the signal is, in principle, achromatic. Another advantage of using such a phase modulator is that it can be placed in the common path traversed by the two orthogonally polarized beams emerging from the beam combiner in a stellar interferometer. Thus the optical components of the modulator do not have to be interferometric quality and could be relatively easily introduced into SUSI. We have investigated the proposed application in a laboratory-based experiment using a Mach-Zehnder interferometer with white-light source. This can be seen as a small model of an amplitude stellar interferometer where the light source takes the place of the distant star and two corner mirrors replaces the entrance pupils of the stellar interferometer

  2. Spectral phase shift and residual angular dispersion of an accousto-optic programme dispersive filter

    Boerzsoenyi, A.; Meroe, M.

    2010-01-01

    Complete text of publication follows. There is an increasing demand for active and precise dispersion control of ultrashort laser pulses. In chirped pulse amplification (CPA) laser systems, the dispersion of the optical elements of the laser has to be compensated at least to the fourth order to obtain high temporal contrast compressed pulses. Nowadays the most convenient device for active and programmable control of spectral phase and amplitude of broadband laser pulses is the acousto-optic programmable dispersive filter (AOPDF), claimed to be able to adjust the spectral phase up to the fourth order. Although it has been widely used, surprisingly enough there has been only a single, low resolution measurement reported on the accuracy of the induced spectral phase shift of the device. In our paper we report on the first systematic experiment aiming at the precise characterization of an AOPDF device. In the experiment the spectral phase shift of the AOPDF device was measured by spectrally and spatially resolved interferometry, which is especially powerful tool to determine small dispersion values with high accuracy. Besides the spectral phase dispersion, we measured both the propagation direction angular dispersion (PDAD) and the phase front angular dispersion (PhFAD). Although the two quantities are equal for plane waves, there may be noticeable difference for Gaussian pulses. PDAD was determined simply by focusing the beam on the slit of an imaging spectrograph, while PhFAD was measured by the use of an inverted Mach-Zehnder interferometer and an imaging spectrograph. In the measurements, the spectral phase shift and both types of angular dispersion have been recorded upon the systematic change of all the accessible functions of the acousto-optic programmable dispersive filter. The measured values of group delay dispersion (GDD) and third order dispersion (TOD) have been found to agree with the preset values within the error of the measurement (1 fs 2 and 10 fs 3

  3. Digital Double-Pulse Holographic Interferometry for Vibration Analysis

    H.J. Tiziani

    1996-01-01

    Full Text Available Different arrangements for double-pulsed holographic and speckle interferometry for vibration analysis will be described. Experimental results obtained with films (classical holographic interferometry and CCD cameras (digital holographic interferometry as storage materials are presented. In digital holography, two separate holograms of an object under test are recorded within a few microseconds using a CCD camera and are stored in a frame grabber. The phases of the two reconstructed wave fields are calculated from the complex amplitudes. The deformation is obtained from the phase difference. In the case of electronic speckle pattern interferometry (or image plane hologram, the phase can be calculated by using the sinusoid-fitting method. In the case of digital holographic interferometry, the phase is obtained by digital reconstruction of the complex amplitudes of the wave fronts. Using three directions of illumination and one direction of observation, all the information necessary for the reconstruction of the 3-dimensional deformation vector can be recorded at the same time. Applications of the method for measuring rotating objects are discussed where a derotator needs to be used.

  4. Seed dispersal in fens

    Middleton, Beth; van Diggelen, Rudy; Jensen, Kai

    Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and

  5. Absolute marine gravimetry with matter-wave interferometry.

    Bidel, Y; Zahzam, N; Blanchard, C; Bonnin, A; Cadoret, M; Bresson, A; Rouxel, D; Lequentrec-Lalancette, M F

    2018-02-12

    Measuring gravity from an aircraft or a ship is essential in geodesy, geophysics, mineral and hydrocarbon exploration, and navigation. Today, only relative sensors are available for onboard gravimetry. This is a major drawback because of the calibration and drift estimation procedures which lead to important operational constraints. Atom interferometry is a promising technology to obtain onboard absolute gravimeter. But, despite high performances obtained in static condition, no precise measurements were reported in dynamic. Here, we present absolute gravity measurements from a ship with a sensor based on atom interferometry. Despite rough sea conditions, we obtained precision below 10 -5  m s -2 . The atom gravimeter was also compared with a commercial spring gravimeter and showed better performances. This demonstration opens the way to the next generation of inertial sensors (accelerometer, gyroscope) based on atom interferometry which should provide high-precision absolute measurements from a moving platform.

  6. Threshold secret sharing scheme based on phase-shifting interferometry.

    Deng, Xiaopeng; Shi, Zhengang; Wen, Wei

    2016-11-01

    We propose a new method for secret image sharing with the (3,N) threshold scheme based on phase-shifting interferometry. The secret image, which is multiplied with an encryption key in advance, is first encrypted by using Fourier transformation. Then, the encoded image is shared into N shadow images based on the recording principle of phase-shifting interferometry. Based on the reconstruction principle of phase-shifting interferometry, any three or more shadow images can retrieve the secret image, while any two or fewer shadow images cannot obtain any information of the secret image. Thus, a (3,N) threshold secret sharing scheme can be implemented. Compared with our previously reported method, the algorithm of this paper is suited for not only a binary image but also a gray-scale image. Moreover, the proposed algorithm can obtain a larger threshold value t. Simulation results are presented to demonstrate the feasibility of the proposed method.

  7. A publication database for optical long baseline interferometry

    Malbet, Fabien; Mella, Guillaume; Lawson, Peter; Taillifet, Esther; Lafrasse, Sylvain

    2010-07-01

    Optical long baseline interferometry is a technique that has generated almost 850 refereed papers to date. The targets span a large variety of objects from planetary systems to extragalactic studies and all branches of stellar physics. We have created a database hosted by the JMMC and connected to the Optical Long Baseline Interferometry Newsletter (OLBIN) web site using MySQL and a collection of XML or PHP scripts in order to store and classify these publications. Each entry is defined by its ADS bibcode, includes basic ADS informations and metadata. The metadata are specified by tags sorted in categories: interferometric facilities, instrumentation, wavelength of operation, spectral resolution, type of measurement, target type, and paper category, for example. The whole OLBIN publication list has been processed and we present how the database is organized and can be accessed. We use this tool to generate statistical plots of interest for the community in optical long baseline interferometry.

  8. Pipeline monitoring with interferometry in non-arid regions

    McCardle, Adrian; Rabus, Bernhard; Ghuman, Parwant [MacDonald Dettwiler, Richmond, BC (Canada); Freymueller, Jeff T. [University of Alaska, Fairbanks (United States)

    2005-07-01

    Interferometry has become a proven technique for accurately measuring ground movements caused by subsidence, landslides, earthquakes and volcanoes. Using space borne sensors such as the ERS, ENVISAT and RADARSAT satellites, ground deformation can be monitored on a millimeter level. Traditionally interferometry has been limited to arid areas however new technology has allowed for successful monitoring in vegetated regions and areas of changing land-cover. Analysis of ground movement of the Trans-Alaskan pipeline demonstrates how these techniques can offer pipeline engineers a new tool for observing potential dangers to pipeline integrity. Results from Interferometric Point Target Analysis were compared with GPS measurements and speckle tracking interferometry was demonstrated to measure a major earthquake. (author)

  9. Practical optical interferometry imaging at visible and infrared wavelengths

    Buscher, David F

    2015-01-01

    Optical interferometry is a powerful technique to make images on angular scales hundreds of times smaller than is possible with the largest telescopes. This concise guide provides an introduction to the technique for graduate students and researchers who want to make interferometric observations and acts as a reference for technologists building new instruments. Starting from the principles of interference, the author covers the core concepts of interferometry, showing how the effects of the Earth's atmosphere can be overcome using closure phase, and the complete process of making an observation, from planning to image reconstruction. This rigorous approach emphasizes the use of rules-of-thumb for important parameters such as the signal-to-noise ratios, requirements for sampling the Fourier plane and predicting image quality. The handbook is supported by web resources, including the Python source code used to make many of the graphs, as well as an interferometry simulation framework, available at www.cambridg...

  10. Deghosting, Demultiple, and Deblurring in Controlled-Source Seismic Interferometry

    Joost van der Neut

    2011-01-01

    Full Text Available With controlled-source seismic interferometry we aim to redatum sources to downhole receiver locations without requiring a velocity model. Interferometry is generally based on a source integral over cross-correlation (CC pairs of full, perturbed (time-gated, or decomposed wavefields. We provide an overview of ghosts, multiples, and spatial blurring effects that can occur for different types of interferometry. We show that replacing cross-correlation by multidimensional deconvolution (MDD can deghost, demultiple, and deblur retrieved data. We derive and analyze MDD for perturbed and decomposed wavefields. An interferometric point spread function (PSF is introduced that can be obtained directly from downhole data. Ghosts, multiples, and blurring effects that may populate the retrieved gathers can be locally diagnosed with the PSF. MDD of perturbed fields can remove ghosts and deblur retrieved data, but it leaves particular multiples in place. To remove all overburden-related effects, MDD of decomposed fields should be applied.

  11. Progress in electron- and ion-interferometry

    Hasselbach, Franz [Institut fuer Angewandte Physik der Universitaet Tuebingen, Auf der Morgenstelle 10, D-72076 Tuebingen (Germany)], E-mail: franz.hasselbach@uni-tuebingen.de

    2010-01-15

    In the 1970s the prominent goal was to overcome the limitations of electron microscopy caused by aberrations of electron lenses by the development of electron holography. In the meantime this problem has been solved, not only in the roundabout way of holography, but directly by correcting the aberrations of the lenses. Nevertheless, many quantitative electron microscopical measurement methods-e.g. mapping and visualization of electric and magnetic fields-were developed within the context of holography and have become fields of their own. In this review we focus on less popular electron interferometric experiments which complement the field of electron holography. The paper is organized as follows. After a short sketch of the development of electron biprism interferometry after its invention in 1954, recent advances in technology are discussed that made electron biprism interferometry an indispensable tool for solving fundamental and applied questions in physics: the development and preparation of conventional and single-atom field electron and field ion sources with their extraordinary properties. Single- and few-atom sources exhibit spectacular features: their brightness at 100 keV exceeds that of conventional field emitters by two orders in magnitude. Due to the extremely small aberrations of diode field emitter extraction optics, the virtual source size of single-atom tips is on the order of 0.2 nm. As a consequence it illuminates an area 7 cm in diameter on a screen at a distance of 15 cm coherently. Projection electron micrographs taken with these sources reach spatial resolutions of atomic dimensions and in-line holograms are-due to the absence of lenses with their aberrations-not blurred. Their reconstruction is straightforward. By addition of a carbon nanotube biprism into the beam path of a projection microscope a lensless electron interferometer has been realized. In extremely ultrahigh vacuum systems flicker noise is practically absent in the new sources

  12. Progress in electron- and ion-interferometry

    Hasselbach, Franz

    2010-01-01

    In the 1970s the prominent goal was to overcome the limitations of electron microscopy caused by aberrations of electron lenses by the development of electron holography. In the meantime this problem has been solved, not only in the roundabout way of holography, but directly by correcting the aberrations of the lenses. Nevertheless, many quantitative electron microscopical measurement methods-e.g. mapping and visualization of electric and magnetic fields-were developed within the context of holography and have become fields of their own. In this review we focus on less popular electron interferometric experiments which complement the field of electron holography. The paper is organized as follows. After a short sketch of the development of electron biprism interferometry after its invention in 1954, recent advances in technology are discussed that made electron biprism interferometry an indispensable tool for solving fundamental and applied questions in physics: the development and preparation of conventional and single-atom field electron and field ion sources with their extraordinary properties. Single- and few-atom sources exhibit spectacular features: their brightness at 100 keV exceeds that of conventional field emitters by two orders in magnitude. Due to the extremely small aberrations of diode field emitter extraction optics, the virtual source size of single-atom tips is on the order of 0.2 nm. As a consequence it illuminates an area 7 cm in diameter on a screen at a distance of 15 cm coherently. Projection electron micrographs taken with these sources reach spatial resolutions of atomic dimensions and in-line holograms are-due to the absence of lenses with their aberrations-not blurred. Their reconstruction is straightforward. By addition of a carbon nanotube biprism into the beam path of a projection microscope a lensless electron interferometer has been realized. In extremely ultrahigh vacuum systems flicker noise is practically absent in the new sources

  13. Atmospheric Phase Delay in Sentinel SAR Interferometry

    Krishnakumar, V.; Monserrat, O.; Crosetto, M.; Crippa, B.

    2018-04-01

    The repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR) Interferometry (InSAR) has been a widely used geodetic technique for observing the Earth's surface, especially for mapping the Earth's topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth's atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere) are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC) of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR). To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET) and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC) images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate height and deformation

  14. ATMOSPHERIC PHASE DELAY IN SENTINEL SAR INTERFEROMETRY

    V. Krishnakumar

    2018-04-01

    Full Text Available The repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR Interferometry (InSAR has been a widely used geodetic technique for observing the Earth’s surface, especially for mapping the Earth’s topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth’s atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR. To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate

  15. Monitoring Unstable Glaciers with Seismic Noise Interferometry

    Preiswerk, L. E.; Walter, F.

    2016-12-01

    Gravity-driven glacier instabilities are a threat to human infrastructure in alpine terrain, and this hazard is likely to increase with future changes in climate. Seismometers have been used previously on hazardous glaciers to monitor the natural englacial seismicity. In some situations, an increase in "icequake" activity may indicate fracture growth and thus an imminent major break-off. However, without independent constraints on unstable volumes, such mere event counting is of little use. A promising new approach to monitor unstable masses in Alpine terrain is coda wave interferometry of ambient noise. While already established in the solid earth, application to glaciers is not straightforward, because the lack of inhomogeneities typically suppresses seismic coda waves in glacier ice. Only glaciers with pervasive crevasses provide enough scattering to generate long codas. This is requirement is likely met for highly dynamic unstable glaciers. Here, we report preliminary results from a temporary 5-station on-ice array of seismometers (corner frequencies: 1 Hz, array aperture: 500m) on Bisgletscher (Switzerland). The seismometers were deployed in shallow boreholes, directly above the unstable tongue of the glacier. In the frequency band 4-12 Hz, we find stable noise cross-correlations, which in principle allows monitoring on a subdaily scale. The origin and the source processes of the ambient noise in these frequencies are however uncertain. As a first step, we evaluate the stability of the sources in order to separate effects of changing source parameters from changes of englacial properties. Since icequakes occurring every few seconds may dominate the noise field, we compare their temporal and spatial occurrences with the cross-correlation functions (stability over time, the asymmetry between causal and acausal parts of the cross-correlation functions) as well as with results from beamforming to assess the influence of these transient events on the noise field.

  16. Super-virtual refraction interferometry: Theory

    Bharadwaj, Pawan

    2011-01-01

    Inverting for the subsurface velocity distribution by refraction traveltime tomography is a well-accepted imaging method by both the exploration and earthquake seismology communities. A significant drawback, however, is that the recorded traces become noisier with increasing offset from the source position, and so prevents accurate picking of traveltimes in far-offset traces. To enhance the signal-to-noise ratio of the far-offset traces, we present the theory of super-virtual refraction interferometry where the signal-to-noise ratio (SNR) of far-offset head-wave arrivals can be theoretically increased by a factor proportional to N; here, N is the number of receiver and source positions associated with the recording and generation of the head-wave arrival. There are two steps to this methodology: correlation and summation of the data to generate traces with virtual head-wave arrivals, followed by the convolution of the data with the virtual traces to create traces with super-virtual head-wave arrivals. This method is valid for any medium that generates head-wave arrivals. There are at least three significant benefits to this methodology: 1). enhanced SNR of far-offset traces so the first-arrival traveltimes of the noisy far-offset traces can be more reliably picked to extend the useful aperture of data, 2). the SNR of head waves in a trace that arrive after the first arrival can be enhanced for accurate traveltime picking and subsequent inversion by traveltime tomography, and 3). common receiver-pair gathers can be analyzed to detect the presence of diving waves in the first arrivals, which can be used to assess the nature of the refracting boundary. © 2011 Society of Exploration Geophysicists.

  17. Photon exchange and decoherence in neutron interferometry

    Sulyok, G.

    2011-01-01

    The general subject of the present work concerns the action of time-dependent, spatially restricted magnetic fields on the wave function of a neutron. Special focus lies on their application in neutron interferometry. For arbitrary time-periodic fields, the corresponding Schroedinger equation is solved analytically. It is then shown, how the occurring exchange of energy quanta between the neutron and the modes of the magnetic field appears in the temporal modulation of the interference pattern between the original wavefunction and the wavefunction altered by the magnetic field. By Fourier analysis of the time-resolved interference pattern, the transition probabilities for all possible energy transfers are deducible. Experimental results for fields consisting of up to five modes are presented. Extending the theoretical approach by quantizing the magnetic field allows deeper insights on the underlying physical processes. For a coherent field state with a high mean photon number, the results of the calculation with classical fields is reproduced. By increasing the number of field modes whose relative phases are randomly distributed, one approaches the noise regime which offers the possibility of modelling decoherence in the neutron interferometer. Options and limitations of this modelling procedure are investigated in detail both theoretically and experimentally. Noise sources are applied in one or both interferometer path, and their strength, frequency bandwidth and position to each other is varied. In addition, the influence of increasing spatial separation of the neutron wave packet is examined, since the resulting Schroedinger cat-like states play an important role in decoherence theory. (author) [de

  18. Interferometry correlations in central p+Pb collisions

    Bożek, Piotr; Bysiak, Sebastian

    2018-01-01

    We present results on interferometry correlations for pions emitted in central p+Pb collisions at √{s_{NN}}=5.02 TeV in a 3+1-dimensional viscous hydrodynamic model with initial conditions from the Glauber Monte Carlo model. The correlation function is calculated as a function of the pion pair rapidity. The extracted interferometry radii show a weak rapidity dependence, reflecting the lack of boost invariance of the pion distribution. A cross term between the out and long directions is found to be nonzero. The results obtained in the hydrodynamic model are in fair agreement with recent data of the ATLAS Collaboration.

  19. Modulated Source Interferometry with Combined Amplitude and Frequency Modulation

    Gutierrez, Roman C. (Inventor)

    1998-01-01

    An improved interferometer is produced by modifying a conventional interferometer to include amplitude and/or frequency modulation of a coherent light source at radio or higher frequencies. The phase of the modulation signal can be detected in an interfering beam from an interferometer and can be used to determine the actual optical phase of the beam. As such, this improvement can be adapted to virtually any two-beam interferometer, including: Michelson, Mach-Zehnder, and Sagnac interferometers. The use of an amplitude modulated coherent tight source results in an interferometer that combines the wide range advantages of coherent interferometry with the precise distance measurement advantages of white light interferometry.

  20. Interferometry correlations in central p+Pb collisions

    Bozek, Piotr; Bysiak, Sebastian [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Krakow (Poland)

    2018-01-15

    We present results on interferometry correlations for pions emitted in central p+Pb collisions at √(s{sub NN}) = 5.02 TeV in a 3 + 1-dimensional viscous hydrodynamic model with initial conditions from the Glauber Monte Carlo model. The correlation function is calculated as a function of the pion pair rapidity. The extracted interferometry radii show a weak rapidity dependence, reflecting the lack of boost invariance of the pion distribution. A cross term between the out and long directions is found to be nonzero. The results obtained in the hydrodynamic model are in fair agreement with recent data of the ATLAS Collaboration. (orig.)

  1. The compact and inexpensive arrowhead setup for holographic interferometry

    Ladera, Celso L; Donoso, Guillermo, E-mail: clladera@usb.v [Departamento de Fisica, Universidad Simon BolIvar, Apdo. 89000, Caracas 1086 (Venezuela, Bolivarian Republic of)

    2011-07-15

    Hologram recording and holographic interferometry are intrinsically sensitive to phase changes, and therefore both are easily perturbed by minuscule optical path perturbations. It is therefore very convenient to bank on holographic setups with a reduced number of optical components. Here we present a compact off-axis holographic setup that requires neither a collimator nor a beam-splitter, and whose layout is reminiscent of an arrowhead. We show that this inexpensive setup is a good alternative for the study and applications of scientific holography by measuring small displacements and deformations of a body. The arrowhead setup will be found particularly useful for holography and holographic interferometry experiments and projects in teaching laboratories.

  2. Mechanical Strain Measurement from Coda Wave Interferometry

    Azzola, J.; Schmittbuhl, J.; Zigone, D.; Masson, F.; Magnenet, V.

    2017-12-01

    Coda Wave Interferometry (CWI) aims at tracking small changes in solid materials like rocks where elastic waves are diffusing. They are intensively sampling the medium, making the technique much more sensitive than those relying on direct wave arrivals. Application of CWI to ambient seismic noise has found a large range of applications over the past years like for multiscale imaging but also for monitoring complex structures such as regional faults or reservoirs (Lehujeur et al., 2015). Physically, observed changes are typically interpreted as small variations of seismic velocities. However, this interpretation remains questionable. Here, a specific focus is put on the influence of the elastic deformation of the medium on CWI measurements. The goal of the present work is to show from a direct numerical and experimental modeling that deformation signal also exists in CWI measurements which might provide new outcomes for the technique.For this purpose, we model seismic wave propagation within a diffusive medium using a spectral element approach (SPECFEM2D) during an elastic deformation of the medium. The mechanical behavior is obtained from a finite element approach (Code ASTER) keeping the mesh grid of the sample constant during the whole procedure to limit numerical artifacts. The CWI of the late wave arrivals in the synthetic seismograms is performed using both a stretching technique in the time domain and a frequency cross-correlation method. Both show that the elastic deformation of the scatters is fully correlated with time shifts of the CWI differently from an acoustoelastic effect. As an illustration, the modeled sample is chosen as an effective medium aiming to mechanically and acoustically reproduce a typical granitic reservoir rock.Our numerical approach is compared to experimental results where multi-scattering of an acoustic wave through a perforated loaded Au4G (Dural) plate is performed at laboratory scale. Experimental and numerical results of the

  3. Time-delay interferometry for LISA

    Tinto, Massimo; Estabrook, F.B.; Armstrong, J.W.

    2002-01-01

    LISA (Laser Interferometer Space Antenna) is a mission to detect and study low-frequency cosmic gravitational radiation through its influence on the phases or frequencies of laser beams exchanged between three remote spacecraft. We previously showed how, with lasers of identical frequencies on stationary spacecraft, the measurement of twelve time series of Doppler shifts could be combined to cancel exactly the phase noise of the lasers and the Doppler fluctuations due to noninertial motions of the six optical benches, while preserving gravitational wave signals. Here we generalize those results on gravitational wave detection with time-delay interferometry to the expected LISA instrument. The six lasers have different center frequencies (in the nominal LISA configuration these center frequencies may well differ by several hundred megahertz) and the distances between spacecraft pairs will change with time (these slowly varying orbital Doppler shifts are expected to be up to tens of megahertz). We develop time-delay data combinations which, as previously, preserve gravitational waves and exactly cancel the leading noise source (phase fluctuations of the six lasers); these data combinations then imply transfer functions for the remaining system noises. Using these, we plot frequency and phase power spectra for modeled system noises in the unequal Michelson combination X and the symmetric Sagnac combination ζ. Although optical bench noise can no longer be cancelled exactly, with the current LISA specifications it is suppressed to negligible levels. It is known that the presently anticipated laser center frequency differences and the orbital Doppler drifts introduce another source of phase noise, arising from the onboard oscillators required to track the photodetector fringes. For the presently planned mission, our analysis indeed demonstrates that noise from current-generation ultrastable oscillators would, if uncorrected, dominate the LISA noise budget. To meet the

  4. Laser interferometry of radiation driven gas jets

    Swanson, Kyle James; Ivanov, Vladimir; Mancini, Roberto; Mayes, Daniel C.

    2017-06-01

    In a series of experiments performed at the 1MA Zebra pulsed power accelerator of the Nevada Terawatt Facility nitrogen gas jets were driven with the broadband x-ray flux produced during the collapse of a wire-array z-pinch implosion. The wire arrays were comprised of 4 and 8, 10μm-thick gold wires and 17μm-thick nickel wires, 2cm and 3cm tall, and 0.3cm in diameter. They radiated 12kJ to 16kJ of x-ray energy, most of it in soft x-ray photons of less than 1keV of energy, in a time interval of 30ns. This x-ray flux was used to drive a nitrogen gas jet located at 0.8cm from the axis of the z-pinch radiation source and produced with a supersonic nozzle. The x-ray flux ionizes the nitrogen gas thus turning it into a photoionized plasma. We used laser interferometry to probe the ionization of the plasma. To this end, a Mach-Zehnder interferometer at the wavelength of 266 nm was set up to extract the atom number density profile of the gas jet just before the Zebra shot, and air-wedge interferometers at 266 and 532 nm were used to determine the electron number density of the plasma right during the Zebra shot. The ratio of electron to atom number densities gives the distribution of average ionization state of the plasma. A python code was developed to perform the image data processing, extract phase shift spatial maps, and obtain the atom and electron number densities via Abel inversion. Preliminary results from the experiment are promising and do show that a plasma has been created in the gas jet driven by the x-ray flux, thus demonstrating the feasibility of a new experimental platform to study photoionized plasmas in the laboratory. These plasmas are found in astrophysical scenarios including x-ray binaries, active galactic nuclei, and the accretion disks surrounding black holes1. This work was sponsored in part by DOE Office of Science Grant DE-SC0014451.1R. C. Mancini et al, Phys. Plasmas 16, 041001 (2009)

  5. Theoretical trends in interferometry of ultrarelativistic nuclear collisions

    Padula, S.S.

    1990-01-01

    A review is made of the main concepts of interferometry, since its discovery in the mid 50's as the HBT effect, until recently, where some new approaches to the field were suggested. A few modifications on the correlation function in the case of high energy collisions are discussed and illustrated. (author)

  6. A new polarized neutron interferometry facility at the NCNR

    Shahi, C.B. [Physics and Engineering Physics Department, Tulane University, New Orleans, LA 70188 (United States); Arif, M. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Cory, D.G. [Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON, Canada N2L 2Y5 (Canada); Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Canadian Institute for Advanced Research, Toronto, ON, Canada M5G 1Z8 (Canada); Mineeva, T. [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Canadian Institute for Advanced Research, Toronto, ON, Canada M5G 1Z8 (Canada); Nsofini, J.; Sarenac, D. [Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Williams, C.J. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Huber, M.G., E-mail: michael.huber@nist.gov [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Pushin, D.A., E-mail: dmitry.pushin@uwaterloo.ca [Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada)

    2016-03-21

    A new monochromatic beamline and facility has been installed at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) devoted to neutron interferometry in the research areas of spin control, spin manipulation, quantum mechanics, quantum information science, spintronics, and material science. This facility is possible in part because of advances in decoherence free subspace interferometer designs that have demonstrated consistent contrast in the presence of vibrational noise; a major environmental constraint that has prevented neutron interferometry from being applied at other neutron facilities. Neutron interferometry measures the phase difference between a neutron wave function propagating along two spatially separated paths. It is a practical example of self interference and due to its modest path separation of a few centimeters allows the insertion of samples and macroscopic neutron spin rotators. Phase shifts can be caused by gravitational, magnetic and nuclear interactions as well as purely quantum mechanical effects making interferometer a robust tool in neutron research. This new facility is located in the guide hall of the NCNR upstream of the existing Neutron Interferometry and Optics Facility (NIOF) and has several advantages over the NIOF including higher incident flux, better neutron polarization, and increased accessibility. The long term goal for the new facility is to be a user supported beamline and makes neutron interferometer more generally available to the scientific community. This paper addresses both the capabilities and characteristics of the new facility.

  7. Matter wave interferometry in the light of Schroedinger's wave mechanics

    1987-01-01

    This is a pre-conference abstracts collection for 67 oral presentations and posters, 62 of them are in INIS scope and are treated individually. The subject matters are interferometers (mainly neutron), interferometry experiments and the related interpretation - and epistemological problems of quantum theory. (qui)

  8. Deformation measurement of a pressure vessel flange by holographic interferometry

    Goncalves Junior, Armando A.; Schneider, C.A.

    1984-01-01

    An automatic metodology used for the measurement of displacement through the holographic interferometry is presented. In order to shown its performance and potentiality, the displacement field from a pipe's and flange, when submited to an internal pressure, is experimentally found. Holography's results are compared with other technique's results. (Author) [pt

  9. Time-lapse controlled-source electromagnetics using interferometry

    Hunziker, J.W.; Slob, E.C.; Wapenaar, C.P.A.

    In time-lapse controlled-source electromagnetics, it is crucial that the source and the receivers are positioned at exactly the same location at all times of measurement. We use interferometry by multidimensional deconvolution (MDD) to overcome problems in repeatability of the source location.

  10. Generation of Bell, NOON and W states via atom interferometry

    Islam, Rameez-ul; Saif, Farhan [Department of Electronics, Quaid-i-Azam University, Islamabad (Pakistan); Khosa, Ashfaq H [Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2008-02-14

    We propose atom interferometric techniques for the generation of Bell, NOON and W states of an electromagnetic field in high-Q cavities. The fundamental constituent of these techniques is off-resonant Bragg diffraction of atomic de Broglie waves. We show good success probabilities for these schemes under the currently available experimental environment of atom interferometry.

  11. Radio astronomical interferometry and x-ray's computerized tomography

    Rodriguez, L F [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1982-01-01

    Radio astronomical interferometry and computerized tomography are techniques of great importance for astronomy and medicine, respectively. In this paper we emphasize that both techniques are based on the same mathematical principles, and present them as an example of interaction between basic and applied science.

  12. Michelson wide-field stellar interferometry : Principles and experimental verification

    Montilla, I.; Pereira, S.F.; Braat, J.J.M.

    2005-01-01

    A new interferometric technique for Michelson wide-field interferometry is presented that consists of a Michelson pupil-plane combination scheme in which a wide field of view can be achieved in one shot. This technique uses a stair-shaped mirror in the intermediate image plane of each telescope in

  13. Back scattering interferometry revisited – A theoretical and experimental investigation

    Jørgensen, Thomas Martini; Jepsen, S. T.; Sørensen, Henrik Schiøtt

    2015-01-01

    A refractive index based detector based on so called back scattering interferometry (BSI) has been described in the literature as a unique optical method for measuring biomolecular binding interactions in solution. In this paper, we take a detailed look at the optical principle underlying this te...

  14. Global-scale seismic interferometry : Theory and numerical examples

    Ruigrok, E.N.; Draganov, D.S.; Wapenaar, K.

    2008-01-01

    Progress in the imaging of the mantle and core is partially limited by the sparse distribution of natural sources; the earthquake hypocenters are mainly along the active lithospheric plate boundaries. This problem can be approached with seismic interferometry. In recent years, there has been

  15. Pion interferometry theory for the hydrodynamic stage of multiple processes

    Makhlin, A.N.; Sinyukov, Yu.M.

    1986-01-01

    The double pion inclusive cross section for identical particles is described in hydrodynamical theory of multiparticle production. The pion interferometry theory is developed for the case when secondary particles are generated against the background of internal relativistic motion of radiative hadron matter. The connection between correlation functions in various schemes of experiment is found within the framework of relativistic Wigner functions formalism

  16. Variantes textuais no Livro do Desassossego: edição, codificação e interpretação

    Diego Giménez

    2016-09-01

    Full Text Available http://dx.doi.org/10.5007/1807-9288.2016v12n1p54 Em 1988, Ivo Castro, responsável pela edição crítica da obra de Fernando Pessoa para a Imprensa Nacional Casa da Moeda, perguntava, numa comunicação intitulada “Edição Crítica de Pessoa: O Modelo Editorial Adoptado”: “como negar ao leitor o máximo de conhecimento sobre o que está escrito por Pessoa nos manuscritos, quando sabemos que dentro de uma geração, provavelmente, nem o leitor, nem nós, seremos ainda capazes de decifrar a tinta sumida dos papéis?”. Neste artigo mantenho que a codificação das fases de escrita no Livro do Desassossego permite representar o processo de composição textual que é interpretado de maneira diferente pelos especialistas. A especificidade da escrita pessoana presenta uma série de dificuldades que os especialistas enfrentam de forma diferente. Desta forma, a comparação entre o trabalho realizado com a edição crítica e o trabalho realizado com a codificação informática permite pôr em paralelo os problemas e soluções adotados em dois momentos diferenciados dos estudos pessoanos e dos estudos humanísticos em geral.

  17. A ansiedade da unidade: uma teoria da edição / L’ansia di unità: Una teoria dell’edizione

    Jerónimo Pizarro

    2016-12-01

    Full Text Available Em 1973 Harold Bloom publicou o livro The Anxiety of Influence: A Theory of Poetry. Uma variação sobre este título poderá ser-nos hoje útil para abordar um outro tipo de ansiedade: o da unidade. Os campos da edição e da interpretação vivem imersos nesse outro tipo de ansiedade. Tanto a interpretação, preocupada com a intenção do autor, da obra ou do leitor, como a edição, angustiada com as intenções finais do autor e o estabelecimento do copy-text, parecem, por vezes, pouco capazes de se libertarem desse ensejo de unidade e de se adaptarem à existência da multiplicidade. Neste artigo, procuro fazer um novo apelo a uma necessária mudança de paradigma, atendendo, em especial, às novas e libertadoras possibilidades potenciadas pela edição electrónica. In 1973 Harold Bloom published his book The Anxiety of Influence: A Theory of Poetry. A variation on this title might be useful for us today to refer to another kind of anxiety: the anxiety of unity. The fields of editing and interpretation lie within this other kind of anxiety. Interpretation, concerned with the author’s, the reader’s or the work’s intention, and editing, worried about the author’s final intentions and the setting up of the copy-text, seem, at times, unable to free themselves from the need to attain unity and adapt to the existence of multiplicity. In this article I intend to make a new appeal on behalf of a change of paradigm, addressing, especially, the new and liberating possibilities of electronic editing

  18. The Psychology of Music, editado por Diana Deutsch, 3ª edição: resenha dos capítulos 10 a 13

    Ricieri Carlini Zorzal

    2016-03-01

    Full Text Available O presente texto traz uma resenha de quatro capítulos da terceira edição do livro The Psychology of Music, editado por Diana Deutsch. Nominalmente, são analisados os seguintes capítulos: 10 Performance musical: movimento e coordenação, de autoria de Caroline Palmer; 11 Desenvolvimento musical, de autoria de Laurel Trainor e Erin Hannon; 12 Música e habilidades cognitivas, de autoria de Glenn Schellenberg e Michael Weiss; e 13 As fundações biológicas da música: insights da amusia congênita, de autoria de Isabelle Peretz.

  19. EDI Performance Statistics

    U.S. Department of Health & Human Services — This section contains statistical information and reports related to the percentage of electronic transactions being sent to Medicare contractors in the formats...

  20. Clock synchronization and dispersion

    Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo; Wong, Franco N C

    2002-01-01

    We present a method to defeat effects of dispersion of timing signals when synchronizing clocks. It is based on the recently proposed 'conveyor belt synchronization' scheme and on the quantum dispersion cancellation effect

  1. Dispersing powders in liquids

    Nelson, RD

    1988-01-01

    This book provides powder technologists with laboratory procedures for selecting dispersing agents and preparing stable dispersions that can then be used in particle size characterization instruments. Its broader goal is to introduce industrial chemists and engineers to the phenomena, terminology, physical principles, and chemical considerations involved in preparing and handling dispersions on a commercial scale. The book introduces novices to: - industrial problems due to improper degree of dispersion; - the nomenclature used in describing particles; - the basic physica

  2. Verification of time-delay interferometry techniques using the University of Florida LISA interferometry simulator

    Mitryk, Shawn J; Wand, Vinzenz; Mueller, Guido, E-mail: smitryk@phys.ufl.ed, E-mail: mueller@phys.ufl.ed [Department of Physics, University of Florida, PO Box 118440, Gainesville, FL 32611-8440 (United States)

    2010-04-21

    Laser Interferometer Space Antenna (LISA) is a cooperative NASA/ESA mission proposed to directly measure gravitational waves (GW) in the frequency range from 30 muHz to 1 Hz with an optimal strain sensitivity of 10{sup -21}/sq root(Hz) at 3 mHz. LISA will utilize a modified Michelson interferometer to measure length changes of 40 pm/sq root(Hz) between drag-free proof masses located on three separate spacecraft (SC) separated by a distance of 5 Gm. The University of Florida has developed a hardware-in-the-loop simulator of the LISA constellation to verify the laser noise cancellation technique known as time-delay interferometry (TDI). We replicate the frequency stabilization of the laser on the local SC and the phase-locking of the lasers on the far SC. The laser photodetector beatnotes are electronically delayed, Doppler shifted and applied with a mock GW signal to simulate the laser link between the SC. The beatnotes are also measured with a LISA-like phasemeter and the data are used to extract the laser phase and residual phase-lock loop noise in post-processing through TDI. This uncovers the GW modulation signal buried under the laser noise. The results are then compared to the requirements defined by the LISA science collaboration.

  3. Um 13 de maio antecipado: edições temáticas, atualidade e memória no circuito TRIP e TPM

    Frederico de Mello Brandão Tavares

    2016-05-01

    Full Text Available Em abril de 2014, as revistas brasileiras TRIP e TPM publicaram uma edição temática, sob o mesmo título base – “Ser negro/negra no Brasil é f*da”, e estabeleceram um diálogo editorial a partir de um gancho temporal: o dia 13 de maio, quando se comemora a abolição da escravatura no país. Com um mês de antecedência e a partir de coberturas estruturadas por conteúdos específicos, em contato ou não, as publicações anteciparam o acontecimento, previsto, encerrando-o em uma “totalidade” de pautas, acionada por seções e provocadora de um circuito que, antes do “acontecer do acontecimento”, atualizou-o como temática, indicando seus sentidos. Neste contexto, o presente artigo observa relações existentes em acionamentos acontecimentais no jornalismo, mesmo quando estes não partem de uma cobertura factual. Tendo como objeto as edições de TRIP e TPM indicadas, busca-se percorrer a transversalidade originada pela tematização das revistas e compreender as afetações e/ou “determinações” que nela aparecem.

  4. Theory of dispersive microlenses

    Herman, B.; Gal, George

    1993-01-01

    A dispersive microlens is a miniature optical element which simultaneously focuses and disperses light. Arrays of dispersive mircolenses have potential applications in multicolor focal planes. They have a 100 percent optical fill factor and can focus light down to detectors of diffraction spot size, freeing up areas on the focal plane for on-chip analog signal processing. Use of dispersive microlenses allows inband color separation within a pixel and perfect scene registration. A dual-color separation has the potential for temperature discrimination. We discuss the design of dispersive microlenses and present sample results for efficient designs.

  5. A novel plasmonic interferometry and the potential applications

    Ali, J.; Pornsuwancharoen, N.; Youplao, P.; Aziz, M. S.; Chiangga, S.; Jaglan, J.; Amiri, I. S.; Yupapin, P.

    2018-03-01

    In this article, we have proposed the plasmonic interferometry concept and analytical details given. By using the conventional optical interferometry, which can be simply calculated by using the relationship between the electric field and electron mobility, the interference mobility visibility (fringe visibility) can be observed. The surface plasmons in the sensing arm of the Michelson interferometer is constructed by the stacked layers of the silicon-graphene-gold, allows to characterize the spatial resolution of light beams in terms of the electron mobility down to 100-nm scales, with measured coherence lengths as low as ∼100 nm for an incident wavelength of 1550 nm. We have demonstrated a compact plasmonic interferometer that can apply to the electron mean free paths measurement, from which the precise determination can be used for the high-resolution mean free path measurement and sensing applications. This system provides the practical simulation device parameters that can be fabricated and tested by the experimental platform.

  6. A recent history of science cases for optical interferometry

    Defrère, Denis; Aerts, Conny; Kishimoto, Makoto; Léna, Pierre

    2018-04-01

    Optical long-baseline interferometry is a unique and powerful technique for astronomical research. Since the 1980's (with I2T, GI2T, Mark I to III, SUSI, ...), optical interferometers have produced an increasing number of scientific papers covering various fields of astrophysics. As current interferometric facilities are reaching their maturity, we take the opportunity in this paper to summarize the conclusions of a few key meetings, workshops, and conferences dedicated to interferometry. We present the most persistent recommendations related to science cases and discuss some key technological developments required to address them. In the era of extremely large telescopes, optical long-baseline interferometers will remain crucial to probe the smallest spatial scales and make breakthrough discoveries.

  7. Phase and fringe order determination in wavelength scanning interferometry.

    Moschetti, Giuseppe; Forbes, Alistair; Leach, Richard K; Jiang, Xiang; O'Connor, Daniel

    2016-04-18

    A method to obtain unambiguous surface height measurements using wavelength scanning interferometry with an improved repeatability, comparable to that obtainable using phase shifting interferometry, is reported. Rather than determining the conventional fringe frequency-derived z height directly, the method uses the frequency to resolve the fringe order ambiguity, and combine this information with the more accurate and repeatable fringe phase derived z height. A theoretical model to evaluate the method's performance in the presence of additive noise is derived and shown to be in good agreement with experiments. The measurement repeatability is improved by a factor of ten over that achieved when using frequency information alone, reaching the sub-nanometre range. Moreover, the z-axis non-linearity (bleed-through or ripple error) is reduced by a factor of ten. These order of magnitude improvements in measurement performance are demonstrated through a number of practical measurement examples.

  8. X-ray Talbot interferometry with capillary plates

    Momose, Atsushi; Kawamoto, Shinya

    2006-01-01

    An X-ray Talbot interferometer consisting of two capillary plates, which were used as X-ray amplitude gratings, was evaluated for X-ray phase imaging. A theoretical aspect of capillary X-ray Talbot interferometry is presented with a preliminary operation result using synchrotron radiation. A two-dimensional X-ray Talbot effect, or self-imaging effect, which was the basis of Talbot interferometry, was observed with the capillary plate, and moire images formed by the X-ray Talbot interferometer exhibited contrasts corresponding to the differential phase shift caused by phase objects placed in front of the interferometer. Finally, the possibility of quantitative phase measurement with a fringe scanning technique is discussed. (author)

  9. MAGIA - using atom interferometry to determine the Newtonian gravitational constant

    Stuhler, J; Fattori, M; Petelski, T; Tino, G M

    2003-01-01

    We describe our experiment MAGIA (misura accurata di G mediante interferometria atomica), in which we will use atom interferometry to perform a high precision measurement of the Newtonian gravitational constant G. Free-falling laser-cooled atoms in a vertical atomic fountain will be accelerated due to the gravitational potential of nearby source masses (SMs). Detecting this acceleration with techniques of Raman atom interferometry will enable us to assign a value to G. To suppress systematic effects we will implement a double-differential measurement. This includes launching two atom clouds in a gradiometer configuration and moving the SMs to different vertical positions. We briefly summarize the general idea of the MAGIA experiment and put it in the context of other high precision G-measurements. We present the current status of the experiment and report on analyses of the expected measurement accuracy

  10. Polarimetric SAR interferometry applied to land ice: modeling

    Dall, Jørgen; Papathanassiou, Konstantinos; Skriver, Henning

    2004-01-01

    This paper introduces a few simple scattering models intended for the application of polarimetric SAR interfer-ometry to land ice. The principal aim is to eliminate the penetration bias hampering ice sheet elevation maps generated with single-channel SAR interferometry. The polarimetric coherent...... scattering models are similar to the oriented-volume model and the random-volume-over-ground model used in vegetation studies, but the ice models are adapted to the different geometry of land ice. Also, due to compaction, land ice is not uniform; a fact that must be taken into account for large penetration...... depths. The validity of the scattering models is examined using L-band polarimetric interferometric SAR data acquired with the EMISAR system over an ice cap located in the percolation zone of the Greenland ice sheet. Radar reflectors were deployed on the ice surface prior to the data acquisition in order...

  11. Demystifying back scatter interferometry: a sensitive refractive index detector

    Jepsen, Søren Terpager; Jørgensen, Thomas Martini; Trydal, Torleif

    2014-01-01

    BACKGROUND: Back Scatter Interferometry (BSI) is a sensitive method for detecting changes of the refractive index (RI) in small capillaries. The method was originally developed as an off-axial column detector for use in Liquid Chromatography or Capillary Electrophoresis systems, but it has been...... acting like a common-path interferometer. METHODS: A HeNe laser is directed at a glass capillary with inner diameter of 1.4 mm and reflected light from air/glass and liquid/glass interfaces interfere to form an RI dependent intensity fringe pattern at a CCD detector. The fringe shift relative...... a common-path interferometer. The sensitivity of the BSI system is given by twice the inner diameter of the capillary times the wavenumber of the light source. Our results suggest that Back Scatter Interferometry does not provide a unique measurement principle for sensing biochemical bindings compared...

  12. Neutron interferometry: The pioneering contributions of Samuel A. Werner

    Klein, A.G.

    2006-01-01

    In 1975, Sam Werner, while on the staff of the Scientific Laboratory of the Ford Motor Company, and his collaborators from Purdue University, Roberto Colella and Albert Overhauser, carried out one of the pioneering experiments in neutron interferometry at the 2 MW University of Michigan research reactor. It was the famous COW Experiment [Colella et al., Phys. Rev. Lett. 34 (1975) 1472] on gravitationally induced quantum interference. Shortly thereafter he moved to University of Missouri in Columbia, to set up a program of neutron scattering research, including neutron interferometry. In the 25 years until his retirement a large number of beautiful experiments have been performed by Sam, with his group, his numerous students and many international collaborators. This work and its history are briefly reviewed in this paper

  13. Holodiagram: elliptic visualizing interferometry, relativity, and light-in-flight.

    Abramson, Nils H

    2014-04-10

    In holographic interferometry, there is usually a static distance separating the point of illumination and the point of observation. In Special Relativity, this separation is dynamic and is caused by the velocity of the observer. The corrections needed to compensate for these separations are similar in the two fields. We use the ellipsoids of the holodiagram for measurement and in a graphic way to explain and evaluate optical resolution, gated viewing, radar, holography, three-dimensional interferometry, Special Relativity, and light-in-flight recordings. Lorentz contraction together with time dilation is explained as the result of the eccentricity of the measuring ellipsoid, caused by its velocity. The extremely thin ellipsoid of the very first light appears as a beam aimed directly at the observer, which might explain the wave or ray duality of light and entanglement. Finally, we introduce the concept of ellipsoids of observation.

  14. Application of synchrotron radiation to X-ray interferometry

    Hart, M [King' s Coll., London (UK). Wheatstone Physics Lab.

    1980-05-01

    X-ray interferometry has been attempted with synchrotron radiation at Hamburg and at Orsay. Experiments will start this year at the Storage Ring Source at Daresbury. This review covers work which has already been completed and outlines the likely trends in phase sensitive X-ray polarimetry, high resolution spectroscopy (including real and imaginary-part EXAFS) and novel experiments with many-beam-case interferometers.

  15. Heterodyne Angle Deviation Interferometry in Vibration and Bubble Measurements

    Ming-Hung Chiu; Jia-Ze Shen; Jian-Ming Huang

    2016-01-01

    We proposed heterodyne angle deviation interferometry (HADI) for angle deviation measurements. The phase shift of an angular sensor (which can be a metal film or a surface plasmon resonance (SPR) prism) is proportional to the deviation angle of the test beam. The method has been demonstrated in bubble and speaker’s vibration measurements in this paper. In the speaker’s vibration measurement, the voltage from the phase channel of a lock-in amplifier includes the vibration level and frequency. ...

  16. Using Atom Interferometry to Search for New Forces

    Wacker, Jay G.

    2009-01-01

    Atom interferometry is a rapidly advancing field and this Letter proposes an experiment based on existing technology that can search for new short distance forces. With current technology it is possible to improve the sensitivity by up to a factor of 10 2 and near-future advances will be able to rewrite the limits for forces with ranges from 100 (micro)m to 1km.

  17. Pion interferometry of ultra-relativistic hadronic collisions

    Kolehmainen, K.

    1986-05-01

    Pion interferometry of ultra-relativistic hadronic collisions is described in the context of the inside-outside cascade model using a current ensemble method capable of describing an arbitrary distribution of pion sources with an arbitrary velocity distribution. The results are quite distinct from the usual Gaussian and Kopylov parameterizations. Extraction of the temperature parameter, effective source lifetime, and transverse size requires a full three-dimensional analysis of the correlation function in terms of the momentum difference. 7 refs., 4 figs

  18. Using atom interferometry to search for new forces

    Wacker, Jay G.

    2010-01-01

    Atom interferometry is a rapidly advancing field and this Letter proposes an experiment based on existing technology that can search for new short distance forces. With current technology it is possible to improve the sensitivity by up to a factor of 10 2 and near-future advances may be able to rewrite the limits for forces with ranges from 1 mm to 100 m.

  19. Atomic Interferometry with Detuned Counter-Propagating Electromagnetic Pulses

    Tsang, Ming -Yee [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-09-05

    Atomic fountain interferometry uses atoms cooled with optical molasses to 1 μK, which are then launched in a fountain mode. The interferometer relies on the nonlinear Raman interaction of counter-propagating visible light pulses. We present models of these key transitions through a series of Hamiltonians. Our models, which have been verified against special cases with known solutions, allow us to incorporate the effects of non-ideal pulse shapes and realistic laser frequency or wavevector jitter.

  20. HBT interferometry and the parton-hadron phase transition

    Soff, S.

    2002-01-01

    We discuss predictions for the pion and kaon interferometry measurements in relativistic heavy ion collisions at SPS and RHIC energies. In particular, we confront relativistic transport model calculations that include explicitly a first-order phase transition from a thermalized quark-gluon plasma to a hadron gas with recent data from the RHIC experiments. We critically examine the HBT puzzle both from the theoretical as well as from the experimental point of view. Alternative scenarios are briefly explained. (orig.)

  1. Pion interferometry and resonances in pp and AA collisions

    Padula, S.S. (UNESP, Inst. de Fisica Teorica, Sao Paulo (Brazil)); Gyulassy, M. (Lawrence Berkeley Lab., Nuclear Science Div., CA (United States))

    1992-07-20

    We study the sensitivity of pion interferometry in pp and anti pp collisions at ISR energies to the resonance abundance. We show that those data are not compatible with the full resonance fractions predicted by the Lund model. The preliminary S+S and O+Au data at 200 A GeV are, however, not incompatible with the Lund predictions, although their sensitivity to resonances is significantly weaker than in the pp/anti pp case. (orig.).

  2. Pion interferometry and resonances in pp and AA collisions

    Padula, S.S.; Gyulassy, M.

    1992-01-01

    We study the sensitivity of pion interferometry in pp and anti pp collisions at ISR energies to the resonance abundance. We show that those data are not compatible with the full resonance fractions predicted by the Lund model. The preliminary S+S and O+Au data at 200 A GeV are, however, not incompatible with the Lund predictions, although their sensitivity to resonances is significantly weaker than in the pp/anti pp case. (orig.)

  3. Pion interferometry and resonances in pp and AA collisions

    Padula, S.S.

    1991-01-01

    We study the sensitivity of pion interferometry in bar pp and bar pp collisions at ISR energies to the resonance abundance. We show that those data are not compatible with the full resonance fractions predicted by the Lund model. The preliminary S+S and O+Au data at 200 GeV are, however, not incompatible with the Lund predictions, although their sensitivity to resonances is significantly weaker than in the pp/bar pp case

  4. Deformation Measurement Of Lumbar Vertebra By Holographic Interferometry

    Matsumoto, Toshiro; Kojima, Arata; Ogawa, Ryoukei; Iwata, Koichi; Nagata, Ryo

    1988-01-01

    The mechanical properties of normal lumbar vertebra and one with the interarticular part cut off to simulate hemi-spondylolysis were measured by the double exposure holographic interferometry. In the normal lumbar vertebra, displacement due to the load applied to the inferior articular process was greater than that of superior articular process under the same load. The interarticular part was subjected to the high stress. From these points, one of the valuable data to consider the cause of spondylolysis was obtained.

  5. Special topics in infrared interferometry. [Michelson interferometer development

    Hanel, R. A.

    1985-01-01

    Topics in IR interferometry related to the development of a Michelson interferometer are treated. The selection and reading of the signal from the detector to the analog to digital converter is explained. The requirements for the Michelson interferometer advance speed are deduced. The effects of intensity modulation on the interferogram are discussed. Wavelength and intensity calibration of the interferometer are explained. Noise sources (Nyquist or Johnson noise, phonon noise), definitions of measuring methods of noise, and noise measurements are presented.

  6. Real-time laser holographic interferometry for aerodynamics

    Lee, G.

    1987-01-01

    Recent developments in thermoplastic recording holograms and advancements in automated image digitalization and analysis make real-time laser holographic interferometry feasible for two-dimensional flows such as airfoil flows. Typical airfoil measurements would include airfoil pressure distributions, wake and boundary layer profiles, and flow field density contours. This paper addresses some of the problems and requirements of a real-time laser holographic interferometer. 13 references

  7. Use of the shearing interferometry for dense inhomogeneous plasma diagnostics

    Zakharenkov, Yu.A.; Sklizkov, G.V.; Shikanov, A.S.

    1980-01-01

    Investigated is a possibility of applying the shearing interferometry for diagnostics of a dense inhomogeneous laser plasma which makes it possible to measure the electron density without losses in accuracy near the critical surface. A shearing interferogram is formed upon interference of two identical images of the object under study shifted at some fixed distance. The value of the interference band deflection inside phase inhomogeneity depends on the gradient of the index of refraction in the direction of shift. It has been found that for studying the inner region of the laser plasma a small shift should be used, and for the external one - a large one. The version of a radial shift interferometry is shown to be optimum. For the inner region of the interferogram the error of the electron density restoration does not exceed 10%, and for the external one the error is comparable with that for the version of standard interferometry. A systematic analysis of the optimum type interferometers shows advantages of shearing interferometers. The maximum electron density recorded in experiments makes up approximately equal to 10 20 cm -3 , which is 3-5 times higher than the corresponding value obtained by a standard double-slit type interferometer at equal limiting parameters of the optical system applied

  8. PNO-apparatus and its test use for neutron interferometry

    Tomimitsu, Hiroshi; Aizawa, Kazuya; Hasegawa, Yuji; Kikuta, Seishi.

    1993-01-01

    Special apparatus 'PNO' of multiutility in the so-called precise neutron optics, such as double or triple crystal diffractometry, interferometry, etc., including neutron diffraction topography, was settled at 3G beam hole in the JRR-3M. In the symposium, several applications of the PNO apparatus are presented as 1) very small angle neutron scattering tool with double crystal arrangement, 2) the characterization of the quality of artificial multilayer lattices made of Ti-Ni by a triple crystal arrangement, 3) the characterization of Ni-base superalloy single crystals by the diffraction topography, which are presented in individual sessions. Preliminary test of the neutron interferometry was also tried with the PNO apparatus. Usual monolithic Si LLL- type interferometer was used with an Al phase shifter in the neutron beam paths. The periodicity of the measured intensity curve was well corresponded to the expected one. The best contrast of the intensity curve was measured as high as 43%. The utility of the PNO-apparatus for neutron interferometry was, thus, approved. (author)

  9. Neutron Interferometry at the National Institute of Standards and Technology

    Huber, M. G.; Sarenac, D.; Nsofini, J.; Pushin, D. A.; Arif, M.; Wood, C. J.; Cory, D. G.; Shahi, C. B.

    2015-01-01

    Neutron interferometry has proved to be a very precise technique for measuring the quantum mechanical phase of a neutron caused by a potential energy difference between two spatially separated neutron paths inside interferometer. The path length inside the interferometer can be many centimeters (and many centimeters apart) making it very practical to study a variety of samples, fields, potentials, and other macroscopic medium and quantum effects. The precision of neutron interferometry comes at a cost; neutron interferometers are very susceptible to environmental noise that is typically mitigated with large, active isolated enclosures. With recent advances in quantum information processing especially quantum error correction (QEC) codes we were able to demonstrate a neutron interferometer that is insensitive to vibrational noise. A facility at NIST’s Center for Neutron Research (NCNR) has just been commissioned with higher neutron flux than the NCNR’s older interferometer setup. This new facility is based on QEC neutron interferometer, thus improving the accessibility of neutron interferometry to the greater scientific community and expanding its applications to quantum computing, gravity, and material research

  10. Characterization methods of integrated optics for mid-infrared interferometry

    Labadie, Lucas; Kern, Pierre Y.; Schanen-Duport, Isabelle; Broquin, Jean-Emmanuel

    2004-10-01

    his article deals with one of the important instrumentation challenges of the stellar interferometry mission IRSI-Darwin of the European Space Agency: the necessity to have a reliable and performant system for beam combination has enlightened the advantages of an integrated optics solution, which is already in use for ground-base interferometry in the near infrared. Integrated optics provides also interesting features in terms of filtering, which is a main issue for the deep null to be reached by Darwin. However, Darwin will operate in the mid infrared range from 4 microns to 20 microns where no integrated optics functions are available on-the-shelf. This requires extending the integrated optics concept and the undergoing technology in this spectral range. This work has started with the IODA project (Integrated Optics for Darwin) under ESA contract and aims to provide a first component for interferometry. In this paper are presented the guidelines of the characterization work that is implemented to test and validate the performances of a component at each step of the development phase. We present also an example of characterization experiment used within the frame of this work, is theoretical approach and some results.

  11. Analysis of surface absorbed dose in X-ray grating interferometry

    Wang, Zhili, E-mail: wangnsrl@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Wu, Zhao; Gao, Kun; Wang, Dajiang; Chen, Heng; Wang, Shenghao [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Wu, Ziyu, E-mail: wuzy@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2014-10-15

    Highlights: • Theoretical framework for dose estimation in X-ray grating interferometry. • Potential dose reduction of X-ray grating interferometry compared to conventional radiography. • Guidelines for optimization of X-ray grating interferometry for dose-sensitive applications. • Measure to compare various existing X-ray phase contrast imaging techniques. - Abstract: X-ray phase contrast imaging using grating interferometry has shown increased contrast over conventional absorption imaging, and therefore the great potential of dose reduction. The extent of the dose reduction depends on the geometry of grating interferometry, the photon energy, the properties of the sample under investigation and the utilized detector. These factors also determine the capability of grating interferometry to distinguish between different tissues with a specified statistical certainty in a single raw image. In this contribution, the required photon number for imaging and the resulting surface absorbed dose are determined in X-ray grating interferometry, using a two-component imaging object model. The presented results confirm that compared to conventional radiography, phase contrast imaging using grating interferometry indeed has the potential of dose reduction. And the extent of dose reduction is strongly dependent on the imaging conditions. Those results provide a theoretical framework for dose estimation under given imaging conditions before experimental trials, and general guidelines for optimization of grating interferometry for those dose-sensitive applications.

  12. Analysis of surface absorbed dose in X-ray grating interferometry

    Wang, Zhili; Wu, Zhao; Gao, Kun; Wang, Dajiang; Chen, Heng; Wang, Shenghao; Wu, Ziyu

    2014-01-01

    Highlights: • Theoretical framework for dose estimation in X-ray grating interferometry. • Potential dose reduction of X-ray grating interferometry compared to conventional radiography. • Guidelines for optimization of X-ray grating interferometry for dose-sensitive applications. • Measure to compare various existing X-ray phase contrast imaging techniques. - Abstract: X-ray phase contrast imaging using grating interferometry has shown increased contrast over conventional absorption imaging, and therefore the great potential of dose reduction. The extent of the dose reduction depends on the geometry of grating interferometry, the photon energy, the properties of the sample under investigation and the utilized detector. These factors also determine the capability of grating interferometry to distinguish between different tissues with a specified statistical certainty in a single raw image. In this contribution, the required photon number for imaging and the resulting surface absorbed dose are determined in X-ray grating interferometry, using a two-component imaging object model. The presented results confirm that compared to conventional radiography, phase contrast imaging using grating interferometry indeed has the potential of dose reduction. And the extent of dose reduction is strongly dependent on the imaging conditions. Those results provide a theoretical framework for dose estimation under given imaging conditions before experimental trials, and general guidelines for optimization of grating interferometry for those dose-sensitive applications

  13. The D18 diffractometer for neutron interferometry at the I.L.L

    Bauspiess, W.

    1978-01-01

    Three things are needed for neutron interferometry: an interferometer (a crystal in the case of Bragg diffraction interferometry), a neutron source, and a device to select and handle the neutrons that shall be used. It is this last technical aspect of neutron interferometry which is discussed in the paper, using as an example the new diffractometer for neutron interferometry that is being built at the I.L.L. Results of performance tests are not presently available but its characteristics are visible from the design. The experimental figures given in the paper refer to experiments performed with the prototype machine, or are extrapolated from said experiments

  14. Matter-wave interferometry with complex nanoparticles

    Geyer, P.

    2015-01-01

    Quantum Mechanics is one of the most thoroughly tested theories in physics; however the quantum phenomena that appear on the microscopic scale are incompatible with the behavior of the macroscopic world. Whether the transition between quantum and classical behavior is virtual or real is still an open question. During my thesis I have built, together with my colleagues, a Talbot-Lau interferometer with light gratings that is capable of handling very large and complex particles. With this device it will be possible to test some of the hypotheses that postulate mechanisms for the quantum to classic transition. During my thesis I have designed the experimental setup using CAD and we assembled the apparatus. I have designed and implemented the data acquisition and experiment control software system MOPS (Molecular Optics Programming System). Furthermore, I have implemented and tested various particle sources for the experiment to bring neutral particles into the gas phase at a velocity and with a beam flux that meets the requirements of the experiment. The Optical Time-domain Interferometer for Matter-waves (OTIMA) is made up of 3 retro-reflected, ⁓7 ns short excimer laser pulses with a wavelength of 157.6 nm, i.e. a grating period of 78.8 nm. The purely optical and pulsed diffraction elements avoid all dispersive interactions that would reduce the interference contrast. Therefore, we expect a high fringe contrast even for large particles; under realistic conditions on earth this type of interferometer is conceptually capable of exploring the wave-particle duality with particles up to 106 amu or even beyond. During my PhD thesis we successfully showed interference for single-photon ionizable molecular clusters up to 2300 amu. Furthermore, we have demonstrated that single-photon fragmentation gratings enable interference experiments with a new class of weakly bound particles and provided interesting perspectives for biomolecules. (author) [de

  15. Electronic speckle-pattern interferometry (ESPI) applied to the study of mechanical behavior of human jaws

    Roman, Juan F.; Moreno de las Cuevas, Vincente; Salgueiro, Jose R.; Suarez, David; Fernandez, Paula; Gallas, Mercedes; Blanchard, Alain

    1996-01-01

    The study of the mechanical behavior of the human jaw during chewing is helpful in several specific medical fields that cover the maxillo-facial area. In this work, electronic speckle pattern interferometry has been applied to study dead jaw bones under external stress which simulates the deformations induced during chewing. Fringes obtained after subtraction of two images of the jaw, the image of the relaxed jaw and that of the jaw under stress, give us information about the most stressed zones. The interferometric analysis proposed here is attractive as it can be done in real time with the jaw under progressive stress. Image processing can be applied for improving the quality of fringes. This research can be of help in orthognathic surgery, for example in diagnosis and treatment of fractured jaws, in oral surgery, and in orthodontics because it would help us to know the stress dispersion when we insert an osseointegrated implant or place an orthodontic appliance, respectively. Studying fragments of human jaw some results about its elasticity and flexibility were obtained.

  16. Wave packet interferometry and quantum state reconstruction by acousto-optic phase modulation

    Tekavec, Patrick F.; Dyke, Thomas R.; Marcus, Andrew H.

    2006-01-01

    Studies of wave packet dynamics often involve phase-selective measurements of coherent optical signals generated from sequences of ultrashort laser pulses. In wave packet interferometry (WPI), the separation between the temporal envelopes of the pulses must be precisely monitored or maintained. Here we introduce a new (and easy to implement) experimental scheme for phase-selective measurements that combines acousto-optic phase modulation with ultrashort laser excitation to produce an intensity-modulated fluorescence signal. Synchronous detection, with respect to an appropriately constructed reference, allows the signal to be simultaneously measured at two phases differing by 90 deg. Our method effectively decouples the relative temporal phase from the pulse envelopes of a collinear train of optical pulse pairs. We thus achieve a robust and high signal-to-noise scheme for WPI applications, such as quantum state reconstruction and electronic spectroscopy. The validity of the method is demonstrated, and state reconstruction is performed, on a model quantum system - atomic Rb vapor. Moreover, we show that our measurements recover the correct separation between the absorptive and dispersive contributions to the system susceptibility

  17. A review of recent work in sub-nanometre displacement measurement using optical and X-ray interferometry.

    Peggs, G N; Yacoot, A

    2002-05-15

    This paper reviews recent work in the field of displacement measurement using optical and X-ray interferometry at the sub-nanometre level of accuracy. The major sources of uncertainty in optical interferometry are discussed and a selection of recent designs of ultra-precise, optical-interferometer-based, displacement measuring transducers presented. The use of X-ray interferometry and its combination with optical interferometry is discussed.

  18. Edição Temática “Cidades inteligentes: planejamento e gestão da sustentabilidade”

    Cláudia Terezinha Kniess

    2016-01-01

    É com satisfação que apresentamos a edição temática da revista Gestão e Secretariado – Revista GeSec - com foco em “Cidades inteligentes: planejamento e gestão da sustentabilidade”. Os estudos nesta temática respondem a uma forte demanda da sociedade para o enfrentamento dos desafios atuais relacionados à crescente concentração da população nos centros urbanos e à diversidade de problemas técnicos e políticos relacionados a esta dinâmica.   A revista GeSeC é classificada como Qualis B...

  19. Integrating effective drought index (EDI) and remote sensing derived parameters for agricultural drought assessment and prediction in Bundelkhand region of India

    Padhee, S. K.; Nikam, B. R.; Aggarwal, S. P.; Garg, V.

    2014-11-01

    Drought is an extreme condition due to moisture deficiency and has adverse effect on society. Agricultural drought occurs when restraining soil moisture produces serious crop stress and affects the crop productivity. The soil moisture regime of rain-fed agriculture and irrigated agriculture behaves differently on both temporal and spatial scale, which means the impact of meteorologically and/or hydrological induced agriculture drought will be different in rain-fed and irrigated areas. However, there is a lack of agricultural drought assessment system in Indian conditions, which considers irrigated and rain-fed agriculture spheres as separate entities. On the other hand recent advancements in the field of earth observation through different satellite based remote sensing have provided researchers a continuous monitoring of soil moisture, land surface temperature and vegetation indices at global scale, which can aid in agricultural drought assessment/monitoring. Keeping this in mind, the present study has been envisaged with the objective to develop agricultural drought assessment and prediction technique by spatially and temporally assimilating effective drought index (EDI) with remote sensing derived parameters. The proposed technique takes in to account the difference in response of rain-fed and irrigated agricultural system towards agricultural drought in the Bundelkhand region (The study area). The key idea was to achieve the goal by utilizing the integrated scenarios from meteorological observations and soil moisture distribution. EDI condition maps were prepared from daily precipitation data recorded by Indian Meteorological Department (IMD), distributed within the study area. With the aid of frequent MODIS products viz. vegetation indices (VIs), and land surface temperature (LST), the coarse resolution soil moisture product from European Space Agency (ESA) were downscaled using linking model based on Triangle method to a finer resolution soil moisture product

  20. Estudo comparativo sobre as atividades experimentais em coleções de Física coincidentes recomendados nas edições 2012 e 2015 do PNLD

    Wendel Fajardo Reis

    2016-09-01

    Full Text Available http://dx.doi.org/10.5007/2175-7941.2016v33n2p462   O Ensino Médio pressupõe uma aprendizagem abrangente e significativa dos conteúdos, em que o professor deve valer-se de recursos didáticos disponíveis e adequados à sua prática. Nessa perspectiva, a atividade experimental torna-se um importante instrumento de ensino a ser explorado no estudo da Física, que também pode ser vivenciado pelos alunos por meio do livro didático (LD. Nesta pesquisa, realiza-se uma análise comparativa das atividades experimentais nas coleções de Física coincidentes nas edições de 2012 e 2015 do Programa Nacional do Livro Didático (PNLD. Para isso, aplica-se a classificação proposta por Barros (2009, fundamentada em competências e habilidades dos Parâmetros Curriculares Nacionais para o Ensino Médio (PCNEM (BRASIL, 1999 e nos temas estruturadores de suas orientações educacionais complementares (PCN+ (BRASIL, 2002. Os resultados mostram uma distribuição não uniforme dos experimentos nos temas da Física, em que ainda prevalecem os arranjos relacionados aos movimentos dos corpos. Para as categorias e dimensões de análise, verifica-se que os autores procuram evidenciar as competências e habilidades do PCNEM, entretanto os aspectos históricos sociais continuam pouco contemplados nas duas edições do Programa. Por fim, espera-se que as informações apresentadas nesse trabalho possam contribuir para a prática docente, com foco nas atividades experimentais dos livros didáticos de Física.

  1. Electromagnetic interferometry in wavenumber and space domains in a layered earth

    Hunziker, J.W.; Slob, E.C.; Fan, Y.; Snieder, R.; Wapenaar, C.P.A.

    2013-01-01

    With interferometry applied to controlled-source electromagnetic data, the direct field and the airwave and all other effects related to the air-water interface can be suppressed in a data-driven way. Interferometry allows for retreival of the scattered field Green’s function of the subsurface or,

  2. Visualization and direct comparison of large displacements using difference holographic interferometry

    Necati Ecevit, F.; Aydin, R.

    1994-01-01

    The difference holographic interferometry provides the possibility of direct comparison of large displacements and deformations of two similar but different objects by application of a special kind of illumination. In this work, the principles of the difference holographic interferometry and the experimental results obtained by applying the single beam technique to large displacements is presented. (author). 10 refs, 4 figs

  3. Dispersal of forest insects

    Mcmanus, M. L.

    1979-01-01

    Dispersal flights of selected species of forest insects which are associated with periodic outbreaks of pests that occur over large contiguous forested areas are discussed. Gypsy moths, spruce budworms, and forest tent caterpillars were studied for their massive migrations in forested areas. Results indicate that large dispersals into forested areas are due to the females, except in the case of the gypsy moth.

  4. Improved new generation dispersants

    Anon.

    1993-01-01

    The use of dispersants to combat oil spills has attracted controversy over the years, and there has been a number of accusations of the chemicals involved doing more harm than good. A new study by the International Petroleum Industry Environmental Conservation Association discusses the positive and the negatives of dispersant use to be considered when drawing up spill contingency plans. (author)

  5. Seed dispersal in fens

    Middleton, B.; Van Diggelen, R.; Jensen, K.

    2006-01-01

    Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and reducing genetic exchange. Species in fragmented wetlands may have lower reproductive success, which can lead to biodiversity loss. While fens may have always been relatively isolated from each other, they have become increasingly fragmented in modern times within agricultural and urban landscapes in both Europe and North America. Dispersal by water, animals and wind has been hampered by changes related to development in landscapes surrounding fens. Because the seeds of certain species are long-lived in the seed bank, frequent episodes of dispersal are not always necessary to maintain the biodiversity of fens. However, of particular concern to restoration is that some dominant species, such as the tussock sedge Carex stricta, may not disperse readily between fens. Conclusions: Knowledge of seed dispersal can be used to maintain and restore the biodiversity of fens in fragmented landscapes. Given that development has fragmented landscapes and that this situation is not likely to change, the dispersal of seeds might be enhanced by moving hay or cattle from fens to damaged sites, or by reestablishing lost hydrological connections. ?? IAVS; Opulus Press.

  6. New developments in NDT through electronic speckle pattern interferometry

    Mohan, S.; Murugesan, P; Mas, R.H.

    2007-01-01

    Full text: Optical holography and speckle interferometry are the emerging optical techniques that can be used for the measurements of microscopic parameters such as displacement, strain, stress and slope. These techniques are applied in various fields such as surface studies, non destructive testing, speckle metrology and steller interferometry. Even though many new NDT methods are available, the suitability for a specific application is based on the material property, nature of defects and sensitivity of detection. Difficulty in radiographic technique is that it fails in detecting tight cracks, planar defects and debonds. Microwave techniques has limited sensitivity for the defect detection and it is not suitable for the objects with metallic cases since the metals are perfect reflectors for the microwaves. Low modulus material attenuates the acoustic energy completely, making ultrasonic testing techniques not feasible. The recently evolved optoelectronic technique namely Electronic Speckle Pattern interferometry (ESPI) is a fast developing optical technique widely used for measuring displacement components, their derivatives, surface roughness, surface contours, shape and others. Due to non contact nature and high sensitivity, this technique has been used as a powerful on line inspection tool for non destructive pattern of materials in industrial environment. The salient feature of ESPI is its capability to display the correlation fringes in a real time on a monitor without the need of photographic processing or optical filtering. ESPI is an alternate non destructive technique suitable for propellant grains and other low modulus materials used in space vehicle systems. The optoelectronic technique can be used to detect cracks, voids and residual stresses etc.., in the components in the industrial environment. In the present investigation, speckle non destructive testing has been carried out on some selected low modulus materials used in space vehicles. The

  7. Application of Phase Shifted, Laser Feedback Interferometry to Fluid Physics

    Ovryn, Ben; Eppell, Steven J.; Andrews, James H.; Khaydarov, John

    1996-01-01

    We have combined the principles of phase-shifting interferometry (PSI) and laser-feedback interferometry (LFI) to produce a new instrument that can measure both optical path length (OPL) changes and discern sample reflectivity variations. In LFI, coherent feedback of the incident light either reflected directly from a surface or reflected after transmission through a region of interest will modulate the output intensity of the laser. LFI can yield a high signal-to-noise ratio even for low reflectivity samples. By combining PSI and LFI, we have produced a robust instrument, based upon a HeNe laser, with high dynamic range that can be used to measure either static (dc) or oscillatory changes along the optical path. As with other forms of interferometry, large changes in OPL require phase unwrapping. Conversely, small phase changes are limited by the fraction of a fringe that can be measured. We introduce the phase shifts with an electro-optic modulator (EOM) and use either the Carre or Hariharan algorithms to determine the phase and visibility. We have determined the accuracy and precision of our technique by measuring both the bending of a cantilevered piezoelectric bimorph and linear ramps to the EOM. Using PSI, sub-nanometer displacements can be measured. We have combined our interferometer with a commercial microscope and scanning piezoelectric stage and have measured the variation in OPL and visibility for drops of PDMS (silicone oil) on coated single crystal silicon. Our measurement of the static contact angle agrees with the value of 68 deg stated in the literature.

  8. Dispersion interferometer for controlled fusion devices

    Drachev, V.P.; Krasnikov, Yu.I.; Bagryansky, P.A.

    1992-01-01

    A common feature in interferometry is the presence of two independent optical channels. Since wave phase in a medium depends on the geometrical path, polarization and radiation frequency, respectively, one can distinguish three types of interferometric schemes when the channels are geometrically separated, or separation occurs in polarizations or radiation frequencies. We have developed a measurement scheme based on a dispersion interferometer (DI) for plasma diagnostics in the experiments on controlled fusion. DI optical channels have the same geometrical path and are separated in radiation frequency. Use of a common optical path causes the main advantage of the DI technique - low sensitivity to vibrations of optical elements. The use of the DI technique for diagnostics of a laser spark in air and of arc discharges has shown its essential advantages as compared to classical interferometers. Interest in the DI technique from the viewpoint of its application in controlled fusion devices is determined also generated by the possibility of developing a compact multichannel interferometer not requiring a vibration isolation structure. (author) 14 refs., 3 figs

  9. Optical polarimetry for noninvasive glucose sensing enabled by Sagnac interferometry.

    Winkler, Amy M; Bonnema, Garret T; Barton, Jennifer K

    2011-06-10

    Optical polarimetry is used in pharmaceutical drug testing and quality control for saccharide-containing products (juice, honey). More recently, it has been proposed as a method for noninvasive glucose sensing for diabetic patients. Sagnac interferometry is commonly used in optical gyroscopes, measuring minute Doppler shifts resulting from mechanical rotation. In this work, we demonstrate that Sagnac interferometers are also sensitive to optical rotation, or the rotation of linearly polarized light, and are therefore useful in optical polarimetry. Results from simulation and experiment show that Sagnac interferometers are advantageous in optical polarimetry as they are insensitive to net linear birefringence and alignment of polarization components.

  10. IMAP: Interferometry for Material Property Measurement in MEMS

    Jensen, B.D.; Miller, S.L.; de Boer, M.P.

    1999-03-10

    An interferometric technique has been developed for non-destructive, high-confidence, in-situ determination of material properties in MEMS. By using interferometry to measure the full deflection curves of beams pulled toward the substrate under electrostatic loads, the actual behavior of the beams has been modeled. No other method for determining material properties allows such detailed knowledge of device behavior to be gathered. Values for material properties and non-idealities (such as support post compliance) have then been extracted which minimize the error between the measured and modeled deflections. High accuracy and resolution have been demonstrated, allowing the measurements to be used to enhance process control.

  11. Sandwich Hologram Interferometry For Determination Of Sacroiliac Joint Movements

    Vukicevic, S.; Vinter, I.; Vukicevic, D.

    1983-12-01

    Investigations were carried out on embalmed and fresh specimens of human pelvisis with preserved lumbar spines, hip joints and all the ligaments. Specimens were tested under static vertical loading by pulsed laser interferometry. The deformations and behaviour of particular pelvic parts were interpreted by providing computer interferogram models. Results indicate rotation and tilting of the sacrum in the dorso-ventral direction and small but significant movements in the cranio-caudal direction. Sandwich holography proved to be the only applicable method when there is a combination of translation and tilt in the range of 200 μm to 1.5 mm.

  12. Precision Gravity Tests with Atom Interferometry in Space

    Tino, G.M.; Sorrentino, F. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Aguilera, D. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Battelier, B.; Bertoldi, A. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Bodart, Q. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Bongs, K. [Midlands Ultracold Atom Research Centre School of Physics and Astronomy University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Bouyer, P. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Braxmaier, C. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Cacciapuoti, L. [European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Gaaloul, N. [Institute of Quantum Optics, Leibniz Universitaet Hannover, Welfengarten 1, D 30167 Hannover (Germany); Gürlebeck, N. [University of Bremen, Centre of Applied Space Technology and Microgravity (ZARM), Am Fallturm, D - 29359 Bremen (Germany); Hauth, M. [Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); and others

    2013-10-15

    Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. This paper presents two possible implementations of a dual {sup 85}Rb-{sup 87}Rb atom interferometer to perform differential gravity measurements in space, with the primary goal to test the Weak Equivalence Principle. The proposed scheme is in the framework of two projects of the European Space Agency, namely Q-WEP and STE-QUEST. The paper describes the baseline experimental configuration, and discusses the technology readiness, noise and error budget for the two proposed experiments.

  13. Weld evaluation on spherical pressure vessels using holographic interferometry

    Boyd, D.M.; Wilcox, W.W.

    1980-01-01

    Waist welds on spherical experimental pressure vessels have been evaluated under pressure using holographic interferometry. A coincident viewing and illumination optical configuration coupled with a parabolic mirror was used so that the entire weld region could be examined with a single hologram. Positioning the pressure vessel at the focal point of the parabolic mirror provides a relatively undistorted 360 degree view of the waist weld. Double exposure and real time holography were used to obtain displacement information on the weld region. Results are compared with radiographic and ultrasonic inspections

  14. Holographic interferometry using a digital photo-camera

    Sekanina, H.; Hledik, S.

    2001-01-01

    The possibilities of running digital holographic interferometry using commonly available compact digital zoom photo-cameras are studied. The recently developed holographic setup, suitable especially for digital photo-cameras equipped with an un detachable object lens, is used. The method described enables a simple and straightforward way of both recording and reconstructing of a digital holographic interferograms. The feasibility of the new method is verified by digital reconstruction of the interferograms acquired, using a numerical code based on the fast Fourier transform. Experimental results obtained are presented and discussed. (authors)

  15. Mapping small elevation changes over large areas - Differential radar interferometry

    Gabriel, Andrew K.; Goldstein, Richard M.; Zebker, Howard A.

    1989-01-01

    A technique is described, based on synthetic aperture radar (SAR) interferometry, which uses SAR images for measuring very small (1 cm or less) surface motions with good resolution (10 m) over swaths of up to 50 km. The method was applied to a Seasat data set of an imaging site in Imperial Valley, California, where motion effects were observed that were identified with movements due to the expansion of water-absorbing clays. The technique can be used for accurate measurements of many geophysical phenomena, including swelling and buckling in fault zones, residual displacements from seismic events, and prevolcanic swelling.

  16. Modelling of a holographic interferometry based calorimeter for radiation dosimetry

    Beigzadeh, A. M.; Vaziri, M. R. Rashidian; Ziaie, F.

    2017-08-01

    In this research work, a model for predicting the behaviour of holographic interferometry based calorimeters for radiation dosimetry is introduced. Using this technique for radiation dosimetry via measuring the variations of refractive index due to energy deposition of radiation has several considerable advantages such as extreme sensitivity and ability of working without normally used temperature sensors that disturb the radiation field. We have shown that the results of our model are in good agreement with the experiments performed by other researchers under the same conditions. This model also reveals that these types of calorimeters have the additional and considerable merits of transforming the dose distribution to a set of discernible interference fringes.

  17. Model-based multi-fringe interferometry using Zernike polynomials

    Gu, Wei; Song, Weihong; Wu, Gaofeng; Quan, Haiyang; Wu, Yongqian; Zhao, Wenchuan

    2018-06-01

    In this paper, a general phase retrieval method is proposed, which is based on one single interferogram with a small amount of fringes (either tilt or power). Zernike polynomials are used to characterize the phase to be measured; the phase distribution is reconstructed by a non-linear least squares method. Experiments show that the proposed method can obtain satisfactory results compared to the standard phase-shifting interferometry technique. Additionally, the retrace errors of proposed method can be neglected because of the few fringes; it does not need any auxiliary phase shifting facilities (low cost) and it is easy to implement without the process of phase unwrapping.

  18. Self-calibration in optical/infrared interferometry

    Millour, Florentin; Dalla Vedova, Gaetan

    2015-08-01

    Optical interferometry produces nowadays images of the observed stars. However, the image quality of the current facilities (VLTI, CHARA) is impaired by the lack of phases measurements. We will describe here a method used to improve the image reconstruction that takes profit of a badly used observable: the wavelength differential phase. This phase shares some properties with the interferometric phase. That method is parent to the self-calibration which was developed in the 80's for radio astronomy to get rid of calibratioon artifacts, and produces a significant improvement on image quality over the current available methods.

  19. Theory of decoherence in Bose-Einstein condensate interferometry

    Dalton, B J [ARC Centre for Quantum-Atom Optics and Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne, Victoria 3122 (Australia)

    2007-05-15

    A full treatment of decoherence and dephasing effects in BEC interferometry has been developed based on using quantum correlation functions for treating interferometric effects. The BEC is described via a phase space distribution functional of the Wigner type for the condensate modes and the positive P type for the non-condensate modes. Ito equations for stochastic condensate and non-condensate field functions replace the functional Fokker-Planck equation for the distribution functional and stochastic averages of field function products determine the quantum correlation functions.

  20. Rapid prototyping of versatile atom chips for atom interferometry applications.

    Kasch, Brian; Squires, Matthew; Olson, Spencer; Kroese, Bethany; Imhof, Eric; Kohn, Rudolph; Stuhl, Benjamin; Schramm, Stacy; Stickney, James

    2016-05-01

    We present recent advances in the manipulation of ultracold atoms with ex-vacuo atom chips (i.e. atom chips that are not inside to the UHV chamber). Details will be presented of an experimental system that allows direct bonded copper (DBC) atom chips to be removed and replaced in minutes, requiring minimal re-optimization of parameters. This system has been used to create Bose-Einstein condensates, as well as magnetic waveguides with precisely tunable axial parameters, allowing double wells, pure harmonic confinement, and modified harmonic traps. We investigate the effects of higher order magnetic field contributions to the waveguide, and the implications for confined atom interferometry.

  1. Spherical grating based x-ray Talbot interferometry

    Cong, Wenxiang, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Xi, Yan, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Wang, Ge, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu [Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-11-15

    Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

  2. From linear optical quantum computing to Heisenberg-limited interferometry

    Lee, Hwang; Kok, Pieter; Williams, Colin P; Dowling, Jonathan P

    2004-01-01

    The working principles of linear optical quantum computing are based on photodetection, namely, projective measurements. The use of photodetection can provide efficient nonlinear interactions between photons at the single-photon level, which is technically problematic otherwise. We report an application of such a technique to prepare quantum correlations as an important resource for Heisenberg-limited optical interferometry, where the sensitivity of phase measurements can be improved beyond the usual shot-noise limit. Furthermore, using such nonlinearities, optical quantum non-demolition measurements can now be carried out easily at the single-photon level

  3. Speckle Interferometry with the OCA Kuhn 22" Telescope

    Wasson, Rick

    2018-04-01

    Speckle interferometry measurements of double stars were made in 2015 and 2016, using the Kuhn 22-inch classical Cassegrain telescope of the Orange County Astronomers, a Point Grey Blackfly CMOS camera, and three interference filters. 272 observations are reported for 177 systems, with separations ranging from 0.29" to 2.9". Data reduction was by means of the REDUC and Speckle Tool Box programs. Equipment, observing procedures, calibration, data reduction, and analysis are described, and unusual results for 11 stars are discussed in detail.

  4. Spherical grating based x-ray Talbot interferometry

    Cong, Wenxiang; Xi, Yan; Wang, Ge

    2015-01-01

    Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

  5. North and northeast Greenland ice discharge from satellite radar interferometry

    Rignot, E.J.; Gogineni, S.P.; Krabill, W.B.

    1997-01-01

    Ice discharge from north and northeast Greenland calculated from satellite radar interferometry data of 14 outlet glaciers is 3.5 times that estimated from iceberg production. The satellite estimates, obtained at the grounding line of the outlet glaciers, differ from those obtained at the glacier...... front, because basal melting is extensive at the underside of the floating glacier sections. The results suggest that the north and northeast parts of the Greenland ice sheet may be thinning and contributing positively to sea-level rise....

  6. Frequency Noise Properties of Lasers for Interferometry in Nanometrology

    Hrabina, Jan; Lazar, Josef; Holá, Miroslava; Číp, Ondřej

    2013-01-01

    Roč. 13, č. 2 (2013), s. 2206-2219 ISSN 1424-8220 R&D Projects: GA ČR GPP102/11/P820; GA ČR GA102/09/1276; GA AV ČR KAN311610701; GA MŠk ED0017/01/01; GA MŠk(CZ) LC06007 Institutional support: RVO:68081731 Keywords : nanometrology * laser noise * interferometry * nanopositioning * AFM Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.048, year: 2013

  7. Meson interferometry and the quest for quark-gluon matter

    Soff, Sven

    2001-01-01

    We point out what we may learn from the investigation of identical two-particle interferometry in ultrarelativistic heavy ion collisions if we assume a particular model scenario by the formation of a thermalized quark-gluon plasma hadronizing via a first-order phase transition to an interacting hadron gas. The bulk properties of the two-pion correlation functions are dominated by these late and soft resonance gas rescattering processes. However, we show that kaons at large transverse momenta have several advantages and a bigger sensitivity to the QCD phase transition parameters

  8. Dispersal and metapopulation stability

    Shaopeng Wang

    2015-10-01

    Full Text Available Metapopulation dynamics are jointly regulated by local and spatial factors. These factors may affect the dynamics of local populations and of the entire metapopulation differently. Previous studies have shown that dispersal can stabilize local populations; however, as dispersal also tends to increase spatial synchrony, its net effect on metapopulation stability has been controversial. Here we present a simple metapopulation model to study how dispersal, in interaction with other spatial and local processes, affects the temporal variability of metapopulations in a stochastic environment. Our results show that in homogeneous metapopulations, the local stabilizing and spatial synchronizing effects of dispersal cancel each other out, such that dispersal has no effect on metapopulation variability. This result is robust to moderate heterogeneities in local and spatial parameters. When local and spatial dynamics exhibit high heterogeneities, however, dispersal can either stabilize or destabilize metapopulation dynamics through various mechanisms. Our findings have important theoretical and practical implications. We show that dispersal functions as a form of spatial intraspecific mutualism in metapopulation dynamics and that its effect on metapopulation stability is opposite to that of interspecific competition on local community stability. Our results also suggest that conservation corridors should be designed with appreciation of spatial heterogeneities in population dynamics in order to maximize metapopulation stability.

  9. Vibration Analysis Of Automotive Structures Using Holographic Interferometry

    Brown, G. M.; Wales, R. R.

    1983-10-01

    Since 1979, Ford Motor Company has been developing holographic interferometry to supplement more conventional test methods to measure vehicle component vibrations. An Apollo PHK-1 Double Pulse Holographic Laser System was employed to visualize a variety of complex vibration modes, primarily on current production and prototype powertrain components. Design improvements to reduce powertrain response to problem excitations have been deter-mined through pulsed laser holography, and have, in several cases, been put into production in Ford vehicles. Whole-field definition of vibration related deflections provide continuity of information missed by accelerometer/modal analysis techniaues. Certain opera-tional problems, common among pulsed ruby holographic lasers, have reauired ongoing hardware and electronics improvements to minimize system downtime. Real-time, time-averaged and stroboscopic C. W. laser holographic techniques are being developed at Ford to complement the double pulse capabilities and provide rapid identification of modal frequencies and nodal lines for analysis of powertrain structures. Methods for mounting and exciting powertrains to minimize rigid body motions are discussed. Work at Ford will continue toward development of C. W. holographic techniques to provide refined test methodology dedicated to noise and vibration diagnostics with particular emphasis on semi-automated methods for quantifying displacement and relative phase using high resolution digitized video and computers. Continued use of refined pulsed and CW laser holographic interferometry for the analysis of complex structure vibrations seems assured.

  10. Electron density interferometry measurement in laser-matter interaction

    Popovics-Chenais, C.

    1981-05-01

    This work is concerned with the laser-interferometry measurement of the electronic density in the corona and the conduction zone external part. Particularly, it is aimed at showing up density gradients and at their space-time localization. The first chapter recalls the density profile influence on the absorption principal mechanisms and the laser energy transport. In chapter two, the numerical and analytical hydrodynamic models describing the density profile are analysed. The influence on the density profile of the ponderomotive force associated to high oscillating electric fields is studied, together with the limited thermal conduction and suprathermal electron population. The mechanism action, in our measurement conditions, is numerically simulated. Calculations are made with experimental parameters. The measurement interaction conditions, together with the diagnostic method by high resolution laser interferometry are detailed. The results are analysed with the help of numerical simulation which is the experiment modeling. An overview of the mechanisms shown up by interferometric measurements and their correlation with other diagnostics is the conclusion of this work [fr

  11. Algorithms and Array Design Criteria for Robust Imaging in Interferometry

    Kurien, Binoy George

    Optical interferometry is a technique for obtaining high-resolution imagery of a distant target by interfering light from multiple telescopes. Image restoration from interferometric measurements poses a unique set of challenges. The first challenge is that the measurement set provides only a sparse-sampling of the object's Fourier Transform and hence image formation from these measurements is an inherently ill-posed inverse problem. Secondly, atmospheric turbulence causes severe distortion of the phase of the Fourier samples. We develop array design conditions for unique Fourier phase recovery, as well as a comprehensive algorithmic framework based on the notion of redundant-spaced-calibration (RSC), which together achieve reliable image reconstruction in spite of these challenges. Within this framework, we see that classical interferometric observables such as the bispectrum and closure phase can limit sensitivity, and that generalized notions of these observables can improve both theoretical and empirical performance. Our framework leverages techniques from lattice theory to resolve integer phase ambiguities in the interferometric phase measurements, and from graph theory, to select a reliable set of generalized observables. We analyze the expected shot-noise-limited performance of our algorithm for both pairwise and Fizeau interferometric architectures and corroborate this analysis with simulation results. We apply techniques from the field of compressed sensing to perform image reconstruction from the estimates of the object's Fourier coefficients. The end result is a comprehensive strategy to achieve well-posed and easily-predictable reconstruction performance in optical interferometry.

  12. Atomic interactions in precision interferometry using Bose-Einstein condensates

    Jamison, Alan O.; Gupta, Subhadeep; Kutz, J. Nathan

    2011-01-01

    We present theoretical tools for predicting and reducing the effects of atomic interactions in Bose-Einstein condensate (BEC) interferometry experiments. To address mean-field shifts during free propagation, we derive a robust scaling solution that reduces the three-dimensional Gross-Pitaevskii equation to a set of three simple differential equations valid for any interaction strength. To model the other common components of a BEC interferometer--condensate splitting, manipulation, and recombination--we generalize the slowly varying envelope reduction, providing both analytic handles and dramatically improved simulations. Applying these tools to a BEC interferometer to measure the fine structure constant, α[S. Gupta, K. Dieckmann, Z. Hadzibabic, and D. E. Pritchard, Phys. Rev. Lett. 89, 140401 (2002)], we find agreement with the results of the original experiment and demonstrate that atomic interactions do not preclude measurement to better than part-per-billion accuracy, even for atomic species with relatively large scattering lengths. These tools help make BEC interferometry a viable choice for a broad class of precision measurements.

  13. A novel plasmonic interferometry and the potential applications

    J. Ali

    2018-03-01

    Full Text Available In this article, we have proposed the plasmonic interferometry concept and analytical details given. By using the conventional optical interferometry, which can be simply calculated by using the relationship between the electric field and electron mobility, the interference mobility visibility (fringe visibility can be observed. The surface plasmons in the sensing arm of the Michelson interferometer is constructed by the stacked layers of the silicon-graphene-gold, allows to characterize the spatial resolution of light beams in terms of the electron mobility down to 100-nm scales, with measured coherence lengths as low as ∼100 nm for an incident wavelength of 1550 nm. We have demonstrated a compact plasmonic interferometer that can apply to the electron mean free paths measurement, from which the precise determination can be used for the high-resolution mean free path measurement and sensing applications. This system provides the practical simulation device parameters that can be fabricated and tested by the experimental platform.

  14. High speed digital holographic interferometry for hypersonic flow visualization

    Hegde, G. M.; Jagdeesh, G.; Reddy, K. P. J.

    2013-06-01

    Optical imaging techniques have played a major role in understanding the flow dynamics of varieties of fluid flows, particularly in the study of hypersonic flows. Schlieren and shadowgraph techniques have been the flow diagnostic tools for the investigation of compressible flows since more than a century. However these techniques provide only the qualitative information about the flow field. Other optical techniques such as holographic interferometry and laser induced fluorescence (LIF) have been used extensively for extracting quantitative information about the high speed flows. In this paper we present the application of digital holographic interferometry (DHI) technique integrated with short duration hypersonic shock tunnel facility having 1 ms test time, for quantitative flow visualization. Dynamics of the flow fields in hypersonic/supersonic speeds around different test models is visualized with DHI using a high-speed digital camera (0.2 million fps). These visualization results are compared with schlieren visualization and CFD simulation results. Fringe analysis is carried out to estimate the density of the flow field.

  15. Multi-link laser interferometry architecture for interspacecraft displacement metrology

    Francis, Samuel P.; Lam, Timothy T.-Y.; McClelland, David E.; Shaddock, Daniel A.

    2018-03-01

    Targeting a future Gravity Recovery and Climate Experiment (GRACE) mission, we present a new laser interferometry architecture that can be used to recover the displacement between two spacecraft from multiple interspacecraft measurements. We show it is possible to recover the displacement between the spacecraft centers of mass in post-processing by forming linear combinations of multiple, spatially offset, interspacecraft measurements. By canceling measurement error due to angular misalignment of the spacecraft, we remove the need for precise placement or alignment of the interferometer, potentially simplifying spacecraft integration. To realize this multi-link architecture, we propose an all-fiber interferometer, removing the need for any ultrastable optical components such as the GRACE Follow-On mission's triple mirror assembly. Using digitally enhanced heterodyne interferometry, the number of links is readily scalable, adding redundancy to our measurement. We present the concept, an example multi-link implementation and the signal processing required to recover the center of mass displacement from multiple link measurements. Finally, in a simulation, we analyze the limiting noise sources in a 9 link interferometer and ultimately show we can recover the 80 {nm}/√{ {Hz}} displacement sensitivity required by the GRACE Follow-On laser ranging interferometer.

  16. Controlled-source seismic interferometry with one way wave fields

    van der Neut, J.; Wapenaar, K.; Thorbecke, J. W.

    2008-12-01

    In Seismic Interferometry we generally cross-correlate registrations at two receiver locations and sum over an array of sources to retrieve a Green's function as if one of the receiver locations hosts a (virtual) source and the other receiver location hosts an actual receiver. One application of this concept is to redatum an area of surface sources to a downhole receiver location, without requiring information about the medium between the sources and receivers, thus providing an effective tool for imaging below complex overburden, which is also known as the Virtual Source method. We demonstrate how elastic wavefield decomposition can be effectively combined with controlled-source Seismic Interferometry to generate virtual sources in a downhole receiver array that radiate only down- or upgoing P- or S-waves with receivers sensing only down- or upgoing P- or S- waves. For this purpose we derive exact Green's matrix representations from a reciprocity theorem for decomposed wavefields. Required is the deployment of multi-component sources at the surface and multi- component receivers in a horizontal borehole. The theory is supported with a synthetic elastic model, where redatumed traces are compared with those of a directly modeled reflection response, generated by placing active sources at the virtual source locations and applying elastic wavefield decomposition on both source and receiver side.

  17. Real-time trichromatic holographic interferometry: preliminary study

    Albe, Felix; Bastide, Myriam; Desse, Jean-Michel; Tribillon, Jean-Louis H.

    1998-08-01

    In this paper we relate our preliminary experiments on real- time trichromatic holographic interferometry. For this purpose a CW `white' laser (argon and krypton of Coherent- Radiation, Spectrum model 70) is used. This laser produces about 10 wavelengths. A system consisting of birefringent plates and polarizers allows to select a trichromatic TEM00 triplet: blue line ((lambda) equals 476 nm, 100 mW), green line ((lambda) equals 514 nm, 100 mW) and red line ((lambda) equals 647 nm, 100 mW). In a first stage we recorded a trichromatic reflection hologram with a separate reference beam on a single-layer silver-halide panchromatic plate (PFG 03C). After processing, the hologram is put back into the original recording set-up, as in classical experiments on real-time monochromatic holographic interferometry. So we observe interference fringes between the 3 reconstructed waves and the 3 actual waves. The interference fringes of the phenomenon are observed on a screen and recorded by a video camera at 25 frames per second. A color video film of about 3 minutes of duration is presented. Some examples related to phase objects are presented (hot airflow from a candle, airflow from a hand). The actual results show the possibility of using this technique to study, in real time, aerodynamic wakes and mechanical deformation.

  18. Interferometry in the era of time-domain astronomy

    Schaefer, Gail H.; Cassan, Arnaud; Gallenne, Alexandre; Roettenbacher, Rachael M.; Schneider, Jean

    2018-04-01

    The physical nature of time variable objects is often inferred from photometric light-curves and spectroscopic variations. Long-baseline optical interferometry has the power to resolve the spatial structure of time variable sources directly in order to measure their physical properties and test the physics of the underlying models. Recent interferometric studies of variable objects include measuring the angular expansion and spatial structure during the early stages of novae outbursts, studying the transits and tidal distortions of the components in eclipsing and interacting binaries, measuring the radial pulsations in Cepheid variables, monitoring changes in the circumstellar discs around rapidly rotating massive stars, and imaging starspots. Future applications include measuring the image size and centroid displacements in gravitational microlensing events, and imaging the transits of exoplanets. Ongoing and upcoming photometric surveys will dramatically increase the number of time-variable objects detected each year, providing many potential targets to observe interferometrically. For short-lived transient events, it is critical for interferometric arrays to have the flexibility to respond rapidly to targets of opportunity and optimize the selection of baselines and beam combiners to provide the necessary resolution and sensitivity to resolve the source as its brightness and size change. We discuss the science opportunities made possible by resolving variable sources using long baseline optical interferometry.

  19. A costal dispersion model

    Rahm, L.; Nyberg, L.; Gidhagen, L.

    1990-01-01

    A dispersion model to be used off costal waters has been developed. The model has been applied to describe the migration of radionuclides in the Baltic sea. A summary of the results is presented here. (K.A.E)

  20. Wave-equation dispersion inversion

    Li, Jing; Feng, Zongcai; Schuster, Gerard T.

    2016-01-01

    We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained

  1. Reactimeter dispersion equation

    A.G. Yuferov

    2016-01-01

    The aim of this work is to derive and analyze a reactimeter metrological model in the form of the dispersion equation which connects reactimeter input/output signal dispersions with superimposed random noise at the inlet. It is proposed to standardize the reactimeter equation form, presenting the main reactimeter computing unit by a convolution equation. Hence, the reactimeter metrological characteristics are completely determined by this unit hardware function which represents a transient re...

  2. Fickian dispersion is anomalous

    Cushman, John H.; O'Malley, Dan

    2015-12-01

    The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.

  3. [Case-control study on effects of external fixation combined with limited internal fixation for the treatment of Pilon fractures of Rüedi-Allgower type III].

    Duan, Da-Peng; You, Wu-Lin; Ji, Le; Zhang, Yong-Tao; Dang, Xiao-Qian; Wang, Kun-Zheng

    2014-01-01

    To analyze the effects of three surgical operations in the treatment of Pilon fracture of Rüedi-Allgower type III, and put forward the best therapeutic method. The clinical data of 33 patients with Pilon fracture who received surgical operations (plaster immobilization group, 10 cases; distal tibia anatomical plate group, 11 cases; external fixation with limited internal fixation group, 12 cases) from October 2009 to January 2012 were analyzed. There were 5 males and 5 females, ranging in age from 24 to 61 years in the plaster immobilization group. There were 7 males and 4 females, ranging in age from 21 to 64 years in the distal tibia anatomical plate group. There were 7 males and 5 females, ranging in age from 23 to 67 years in the external fixation with limited internal fixation group. The Ankle X-ray of Pilon fracture after operation, ankle score, early and late complications were collected. Bourne system was used to evaluate ankle joint function. After 8 months to 3 years follow-up, it was found that three kinds of treatment had significant differences in the outcomes and complications (P external fixation with limited internal fixation group got the best results. The number of anatomic reduction cases in the external fixation with limited internal fixation group (7 cases) and the distal tibia anatomical plate group (8 cases) was more than the plaster immobilization group (2 cases). According to the ankle score, 8 patients got an excellent result, 3 good and 1 poor in the limited internal fixation group ,which was better than those of distal tibia anatomical plate group (5 excellent, 4 good and 2 poor) and the plaster immobilization group (3 excellent, 4 good and 3 poor). The number of early and late complications in the external fixation with limited internal fixation group was more than those in the plaster immobilization group and the distal tibia anatomical plate group (Pexternal fixation with limited internal fixation in the treatment of Pilon fracture

  4. JAMSTEC E-library of Deep-sea Images (J-EDI) Realizes a Virtual Journey to the Earth's Unexplored Deep Ocean

    Sasaki, T.; Azuma, S.; Matsuda, S.; Nagayama, A.; Ogido, M.; Saito, H.; Hanafusa, Y.

    2016-12-01

    The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) archives a large amount of deep-sea research videos and photos obtained by JAMSTEC's research submersibles and vehicles with cameras. The web site "JAMSTEC E-library of Deep-sea Images : J-EDI" (http://www.godac.jamstec.go.jp/jedi/e/) has made videos and photos available to the public via the Internet since 2011. Users can search for target videos and photos by keywords, easy-to-understand icons, and dive information at J-EDI because operating staffs classify videos and photos as to contents, e.g. living organism and geological environment, and add comments to them.Dive survey data including videos and photos are not only valiant academically but also helpful for education and outreach activities. With the aim of the improvement of visibility for broader communities, we added new functions of 3-dimensional display synchronized various dive survey data with videos in this year.New Functions Users can search for dive survey data by 3D maps with plotted dive points using the WebGL virtual map engine "Cesium". By selecting a dive point, users can watch deep-sea videos and photos and associated environmental data, e.g. water temperature, salinity, rock and biological sample photos, obtained by the dive survey. Users can browse a dive track visualized in 3D virtual spaces using the WebGL JavaScript library. By synchronizing this virtual dive track with videos, users can watch deep-sea videos recorded at a point on a dive track. Users can play an animation which a submersible-shaped polygon automatically traces a 3D virtual dive track and displays of dive survey data are synchronized with tracing a dive track. Users can directly refer to additional information of other JAMSTEC data sites such as marine biodiversity database, marine biological sample database, rock sample database, and cruise and dive information database, on each page which a 3D virtual dive track is displayed. A 3D visualization of a dive

  5. Resolving power test of 2-D K{sup +} K{sup +} interferometry

    Padula, Sandra S.; Roldao, Christiane G. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil)

    1999-07-01

    Adopting a procedure previously proposed to quantitatively study pion interferometry {sup 1} , an equivalent 2-D X{sup 2} analysis was performed to test the resolving power of that method when applied to less favorable conditions, when no significant contribution from long lived resonances is expected, as in kaon interferometry. For that purpose, use is made of the preliminary E859 K{sup +}K{sup +} interferometry data from Si+Au collisions at 14.6 A GeV/c. Less sensitivity is achieved in the present case, although it is shown that it is still possible to distinguish two distinct decoupling geometries. (author)

  6. Refractometry and interferometry in chemical analysis; Refractometrie et interferometrie en analyse chimique

    Veret, C [Faculte des Sciences de Paris, 75 (France)

    2000-03-01

    In vacuum, an electromagnetic radiation is propagated at a constant velocity. But, when it has to pass through a physical medium, it is submitted to different interactions (for instance: absorption, diffusion, refraction, polarization, dispersion, fluorescence) which lead to a modification of its propagation. In the frequency ranges of the radiation for which the absorption is not very important, the modifications of the propagation velocity of a radiation can bring data on the nature and/or the physical conditions (pressure, temperature) of a medium, whatever its state be: gas, liquid or solid. Thus, the absolute refractive index of a medium in relation to vacuum is defined as the ratio c/v of the propagation velocity c of a monochromatic electromagnetic radiation in vacuum at its velocity v in this medium. The photonic refractometry (field of ultraviolet, visible and infrared radiations) is the set of the measure techniques of the refractive indexes having a role in chemical analysis. The refractometry measures can only be applied to media which are optically transparent. After having described these techniques, the author presents their uses in chemical analysis. (O.M.)

  7. Utilization of coincidence criteria in absolute length measurements by optical interferometry in vacuum and air

    Schödel, R

    2015-01-01

    Traceability of length measurements to the international system of units (SI) can be realized by using optical interferometry making use of well-known frequencies of monochromatic light sources mentioned in the Mise en Pratique for the realization of the metre. At some national metrology institutes, such as Physikalisch-Technische Bundesanstalt (PTB) in Germany, the absolute length of prismatic bodies (e.g. gauge blocks) is realized by so-called gauge-block interference comparators. At PTB, a number of such imaging phase-stepping interference comparators exist, including specialized vacuum interference comparators, each equipped with three highly stabilized laser light sources. The length of a material measure is expressed as a multiple of each wavelength. The large number of integer interference orders can be extracted by the method of exact fractions in which the coincidence of the lengths resulting from the different wavelengths is utilized as a criterion. The unambiguous extraction of the integer interference orders is an essential prerequisite for correct length measurements. This paper critically discusses coincidence criteria and their validity for three modes of absolute length measurements: 1) measurements under vacuum in which the wavelengths can be identified with the vacuum wavelengths, 2) measurements under air in which the air refractive index is obtained from environmental parameters using an empirical equation, and 3) measurements under air in which the air refractive index is obtained interferometrically by utilizing a vacuum cell placed along the measurement pathway. For case 3), which corresponds to PTB’s Kösters-Comparator for long gauge blocks, the unambiguous determination of integer interference orders related to the air refractive index could be improved by about a factor of ten when an ‘overall dispersion value,’ suggested in this paper, is used as coincidence criterion. (paper)

  8. Imaging and Measuring Electron Beam Dose Distributions Using Holographic Interferometry

    Miller, Arne; McLaughlin, W. L.

    1975-01-01

    Holographic interferometry was used to image and measure ionizing radiation depth-dose and isodose distributions in transparent liquids. Both broad and narrowly collimated electron beams from accelerators (2–10 MeV) provided short irradiation times of 30 ns to 0.6 s. Holographic images...... and measurements of absorbed dose distributions were achieved in liquids of various densities and thermal properties and in water layers thinner than the electron range and with backings of materials of various densities and atomic numbers. The lowest detectable dose in some liquids was of the order of a few k......Rad. The precision limits of the measurement of dose were found to be ±4%. The procedure was simple and the holographic equipment stable and compact, thus allowing experimentation under routine laboratory conditions and limited space....

  9. Super-virtual refraction interferometry: an engineering field data example

    Hanafy, Sherif M.

    2012-10-01

    The theory of super-virtual refraction interferometry (SVI) was recently developed to enhance the signal-to-noise ratio (SNR) of far-offset traces in refraction surveys. This enhancement of the SNR is proportional to √N and can be as high as N if an iterative procedure is used. Here N is the number of post-critical shot positions that coincides with the receiver locations. We now demonstrate the SNR enhancement of super-virtual refraction traces for one engineering-scale synthetic data and two field seismic data sets. The field data are collected over a normal fault in Saudi Arabia. Results show that both the SNR of the super-virtual data set and the number of reliable first-arrival traveltime picks are significantly increased. © 2012 European Association of Geoscientists & Engineers.

  10. Vegetation Parameter Extraction Using Dual Baseline Polarimetric SAR Interferometry Data

    Zhang, H.; Wang, C.; Chen, X.; Tang, Y.

    2009-04-01

    For vegetation parameter inversion, the single baseline polarimetric SAR interferometry (POLinSAR) technique, such as the three-stage method and the ESPRIT algorithm, is limited by the observed data with the minimum ground to volume amplitude ration, which effects the estimation of the effective phase center for the vegetation canopy or the surface, and thus results in the underestimated vegetation height. In order to remove this effect of the single baseline inversion techniques in some extend, another baseline POLinSAR data is added on vegetation parameter estimation in this paper, and a dual baseline POLinSAR technique for the extraction of the vegetation parameter is investigated and improved to reduce the dynamic bias for the vegetation parameter estimation. Finally, the simulated data and real data are used to validate this dual baseline technique.

  11. Very Long Baseline Interferometry: Dependencies on Frequency Stability

    Nothnagel, Axel; Nilsson, Tobias; Schuh, Harald

    2018-04-01

    Very Long Baseline Interferometry (VLBI) is a differential technique observing radiation of compact extra-galactic radio sources with pairs of radio telescopes. For these observations, the frequency standards at the telescopes need to have very high stability. In this article we discuss why this is, and we investigate exactly how precise the frequency standards need to be. Four areas where good clock performance is needed are considered: coherence, geodetic parameter estimation, correlator synchronization, and UT1 determination. We show that in order to ensure the highest accuracy of VLBI, stability similar to that of a hydrogen maser is needed for time-scales up to a few hours. In the article, we are considering both traditional VLBI where extra-galactic radio sources are observed, as well as observation of man-made artificial radio sources emitted by satellites or spacecrafts.

  12. Speckle interferometry application for erosion measurements in fusion devices

    Gauthier, E.; Roupillard, R. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2003-07-01

    In order to measure erosion/redeposition in fusion devices, a new diagnostic based on speckle interferometry is investigated. First experiments performed on carbon fibre composite (CFC) materials have shown that this technique is able to measure a modification of the surface in the range of 1 {mu}m. Further experiments have been performed on different materials using a second wavelength in order to carry out 3-dimensional measurements of the surface and to increase the dynamic range of the depth measurement. A diagnostic, based on two-wavelength TV-holography to measure in situ erosion/redeposition during long duration discharges on the CIEL limiter in Tore Supra, is under development at CEA Cadarache. (authors)

  13. Damage monitoring in historical murals by speckle interferometry

    Hinsch, Klaus D.; Gulker, Gerd; Joost, Holger

    2003-11-01

    In the conservation of historical murals it is important to identify loose plaster sections that threaten to fall off. Electronic speckle interferometry in combination with acoustic excitation of the object has been employed to monitor loose areas. To avoid disadvantages of high sound irradiation of the complete building a novel directional audio-sound source based on nonlinear mixing of ultrasound has been introduced. The optical system was revised for optimum performance in the new environment. Emphasis is placed on noise suppression to increase sensitivity. Furthermore, amplitude and phase data of object response over the frequency-range inspected are employed to gain additional information on the state of the plaster or paint. Laboratory studies on sample specimen supplement field campaigns at historical sites.

  14. High-speed digital holographic interferometry for vibration measurement

    Pedrini, Giancarlo; Osten, Wolfgang; Gusev, Mikhail E.

    2006-01-01

    A system based on digital holographic interferometry for the measurement of vibrations is presented. A high-power continuous laser(10 W) and a high-speed CCD camera are used. Hundreds of holograms of an object that has been subjected to dynamic deformation are recorded. The acquisition speed and the time of exposure of the detector are determined by the vibration frequency. Two methods are presented for triggering the camera in order to acquire at a given phase of the vibration. The phase of the wavefront is calculated from the recorded holograms by use of a two-dimensional digital Fourier-transform method. The deformation of the object is obtained from the phase. By combination of the deformations recorded at different times it is possible to reconstruct the vibration of the object

  15. Point source atom interferometry with a cloud of finite size

    Hoth, Gregory W., E-mail: gregory.hoth@nist.gov; Pelle, Bruno; Riedl, Stefan; Kitching, John; Donley, Elizabeth A. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2016-08-15

    We demonstrate a two axis gyroscope by the use of light pulse atom interferometry with an expanding cloud of atoms in the regime where the cloud has expanded by 1.1–5 times its initial size during the interrogation. Rotations are measured by analyzing spatial fringe patterns in the atom population obtained by imaging the final cloud. The fringes arise from a correlation between an atom's initial velocity and its final position. This correlation is naturally created by the expansion of the cloud, but it also depends on the initial atomic distribution. We show that the frequency and contrast of these spatial fringes depend on the details of the initial distribution and develop an analytical model to explain this dependence. We also discuss several challenges that must be overcome to realize a high-performance gyroscope with this technique.

  16. Permutational symmetries for coincidence rates in multimode multiphotonic interferometry

    Khalid, Abdullah; Spivak, Dylan; Sanders, Barry C.; de Guise, Hubert

    2018-06-01

    We obtain coincidence rates for passive optical interferometry by exploiting the permutational symmetries of partially distinguishable input photons, and our approach elucidates qualitative features of multiphoton coincidence landscapes. We treat the interferometer input as a product state of any number of photons in each input mode with photons distinguished by their arrival time. Detectors at the output of the interferometer count photons from each output mode over a long integration time. We generalize and prove the claim of Tillmann et al. [Phys. Rev. X 5, 041015 (2015), 10.1103/PhysRevX.5.041015] that coincidence rates can be elegantly expressed in terms of immanants. Immanants are functions of matrices that exhibit permutational symmetries and the immanants appearing in our coincidence-rate expressions share permutational symmetries with the input state. Our results are obtained by employing representation theory of the symmetric group to analyze systems of an arbitrary number of photons in arbitrarily sized interferometers.

  17. Laboratory demonstration of Stellar Intensity Interferometry using a software correlator

    Matthews, Nolan; Kieda, David

    2017-06-01

    In this talk I will present measurements of the spatial coherence function of laboratory thermal (black-body) sources using Hanbury-Brown and Twiss interferometry with a digital off-line correlator. Correlations in the intensity fluctuations of a thermal source, such as a star, allow retrieval of the second order coherence function which can be used to perform high resolution imaging and source geometry characterization. We also demonstrate that intensity fluctuations between orthogonal polarization states are uncorrelated but can be used to reduce systematic noise. The work performed here can readily be applied to existing and future Imaging Air-Cherenkov telescopes to measure spatial properties of stellar sources. Some possible candidates for astronomy applications include close binary star systems, fast rotators, Cepheid variables, and potentially even exoplanet characterization.

  18. AMiBA: BROADBAND HETERODYNE COSMIC MICROWAVE BACKGROUND INTERFEROMETRY

    Chen, M.-T.; Li, C.-T.; Hwang, Y.-J.; Jiang Homin; Altamirano, Pablo; Chang, C.-H.; Chang, S.-H.; Chang, S.-W.; Han, C.-C.; Huang, Y.-D.; Kubo, Derek; Martin-Cocher, Pierre; Oshiro, Peter; Raffin, Philippe; Wei Tashun; Chiueh, T.-D.; Chu, T.-H.; Wang Huei; Kesteven, Michael; Wilson, Warwick

    2009-01-01

    The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first results on the detection of galaxy clusters via the Sunyaev-Zel'dovich effect. The objectives required small reflectors in order to sample large-scale structures (20'), while interferometry provided modest resolutions (2'). With these constraints, we designed for the best sensitivity by utilizing the maximum possible continuum bandwidth matched to the atmospheric window at 86-102 GHz, with dual polarizations. A novel wide-band analog correlator was designed that is easily expandable for more interferometer elements. Monolithic millimeter-wave integrated circuit technology was used throughout as much as possible in order to miniaturize the components and to enhance mass production. These designs will find application in other upcoming astronomy projects. AMiBA is now in operation since 2006, and we are in the process to expand the array from seven to 13 elements.

  19. All-optical optoacoustic microscope based on wideband pulse interferometry.

    Wissmeyer, Georg; Soliman, Dominik; Shnaiderman, Rami; Rosenthal, Amir; Ntziachristos, Vasilis

    2016-05-01

    Optical and optoacoustic (photoacoustic) microscopy have been recently joined in hybrid implementations that resolve extended tissue contrast compared to each modality alone. Nevertheless, the application of the hybrid technique is limited by the requirement to combine an optical objective with ultrasound detection collecting signal from the same micro-volume. We present an all-optical optoacoustic microscope based on a pi-phase-shifted fiber Bragg grating (π-FBG) with coherence-restored pulsed interferometry (CRPI) used as the interrogation method. The sensor offers an ultra-small footprint and achieved higher sensitivity over piezoelectric transducers of similar size. We characterize the spectral bandwidth of the ultrasound detector and interrogate the imaging performance on phantoms and tissues. We show the first optoacoustic images of biological specimen recorded with π-FBG sensors. We discuss the potential uses of π-FBG sensors based on CRPI.

  20. Interferometry and MHD turbulence measurements in toroidal pinches

    Dutt, T.L.; Evans, D.E.; Wilcock, P.D.

    1976-01-01

    A 10.6 micron interferometer produced 2 to 3 good quality fringes in the HBTX plasma. There is substantial agreement in the electron densities determined by interferometry and by Thomson scattering, but since the former is an absolute measurement and is systematically lower than the Thomson scattering values, the latter may be too great by about 35%. In RF Pinches, turbulence associated with the instability deflects the beam and corrupts the interferogram. However, if the intensity fluctuations induced in this beam by the turbulence, are measured, as is done in the second experiment performed in the FRSX plasma with a HCN laser, the frequency spectrum of the turbulence can be deduced. In this plasma, rms fluctuations in the density were measured by this means to be 20%, and the dominant frequency of the fluctuations multiplied by the tube diameter was approximately Alfven speed, favouring an interpretation of the gross turbulence in this plasma in terms of Alfen waves. (U.K.)

  1. Intensity interferometry at the X13A undulator beamline

    Gluskin, E.; McNulty, I.; Yang, L.; Randall, K.J.; Johnson, E.D.

    1993-01-01

    We are constructing a soft x-ray intensity interferometer and an undulator based beamline to demonstrate intensity interferometry in the x-ray region. The 10-period soft x-ray undulator at the NSLS provides the necessary coherent flux; the X13A beamline is designed to preserve the spatial coherence of the bright x-ray beam and provide sufficient temporal coherence using a horizontally deflecting spherical grating monochromator. Using the interferometer, which consists of an array of small slits, a wedge-shaped beamsplitter and two fast microchannel plate detectors, we expect to measure the spatial coherence of the undulator beam and therefore the size of the source in the vertical plane. Details of the bean-dine design and the interferometer experiment are discussed

  2. Rapid microcantilever-thickness determination by optical interferometry

    Salmon, Andrew R; Capener, Matthew J; Elliott, Stephen R; Baumberg, Jeremy J

    2014-01-01

    Silicon microcantilevers are widely used in scanning-probe microscopy and in cantilever-sensing applications. However, the cantilever thickness is not well controlled in conventional lithography and, since it is also difficult to measure, it is the most important undefined factor in mechanical variability. An accurate method to measure this parameter is thus essential. We demonstrate the capability to measure microcantilever thicknesses rapidly (>1 Hz) and accurately (±2 nm) by optical interferometry. This is achieved with standard microscopy equipment and so can be implemented as a standard technique in both research and in batch control for commercial microfabrication. In addition, we show how spatial variations in the thickness of individual microcantilevers can be mapped, which has applications in the precise mechanical calibration of cantilevers for force spectroscopy. (paper)

  3. Optical transition radiation interferometry for the A0 photoinjector

    Kazakevich, G.; Novosibirsk, IYF; Edwards, H.; Fliller, R.; Nagaitsev, S.; Ruan, J.; Thurman-Keup, R.; Fermilab

    2008-01-01

    Optical Transition Radiation Interferometry (OTRI) is a promising diagnostic technique and has been successfully developed and used for investigation of relativistic beams. For mid-energy accelerators the technique is traditionally based on thin polymer films (the first one is being transparent for visible light), which causes beam multiple scattering of about 1 mrad. A disadvantage of those films is unacceptable vacuum properties for photoinjectors and accelerators using superconducting cavities. We have studied the application of thin mica sheets for the OTRI diagnostics at the A0 Photoinjector in comparison with 2.5 (micro)m thick Mylar films. This diagnostic is also applicable for the ILCTA-NML accelerator test facility that is planned at Fermilab. This report discusses the experimental setups of the OTR interferometer for the A0 Photoinjector and presents comparisons of simulations and measurements obtained using Mylar and mica-based interferometers

  4. Super-virtual refraction interferometry: an engineering field data example

    Hanafy, Sherif M.; Alhagan, Ola

    2012-01-01

    The theory of super-virtual refraction interferometry (SVI) was recently developed to enhance the signal-to-noise ratio (SNR) of far-offset traces in refraction surveys. This enhancement of the SNR is proportional to √N and can be as high as N if an iterative procedure is used. Here N is the number of post-critical shot positions that coincides with the receiver locations. We now demonstrate the SNR enhancement of super-virtual refraction traces for one engineering-scale synthetic data and two field seismic data sets. The field data are collected over a normal fault in Saudi Arabia. Results show that both the SNR of the super-virtual data set and the number of reliable first-arrival traveltime picks are significantly increased. © 2012 European Association of Geoscientists & Engineers.

  5. Thermal strain measurements in graphite using electronic speckle pattern interferometry

    Tamulevicius, S.; Augulis, L.; Augulis, R.; Zabarskas, V.; Levinskas, R.; Poskas, P.

    2001-01-01

    Two 1500 MW(e) RBMK Units are operated at Ignalina NPP in Lithuania. Due to recent decision of the Parliament on the earlier closure of Unit 1, preparatory work for decommissioning have been initiated. Preferred decommissioning strategy is based on delayed dismantling after rather long safe enclosure period. Since graphite is one of the basic and probably the most voluminous components of the reactor internals, a sufficient information on status and behaviour of graphite moderator and reflector during long time safe enclosure period is of special significance. In this context, thermal strain in graphite is one of the parameters requiring particular interest. Electronic speckle pattern interferometry has been proposed and successfully tested to control this parameter using the real samples of graphite from Ignalina NPP Units. (author)

  6. The photographic edition as a visual narrative construction A edição fotográfica como construção de uma narrativa visual

    Fernanda Jansen Mira Catanho

    2007-01-01

    Full Text Available This article, based on the concept of intellectual montage, developed by russian movie director Sergei Eisenstein, works in the premises that the photographic edition may be responsible for the construction of a visual narrative. Thus, it adopts a photographic essay composed of 26 pictures and sends it to three specialists for edition. The results are three different narratives. With this, it becomes evident that the photographic message may undergo a creative rearrange and compose distinctive enunciation discourses. At the end, the work shows that the differences between the discourses elaborated by the editors are captured by the receiver of the photographic message. Este artigo, baseado no conceito de montagem intelectual, desenvolvido pelo cineasta russo Sergei Eisenstein, trabalha com a premissa de que a edição fotográfica pode ser responsável pela construção de uma narrativa visual. Para tanto, adota um ensaio fotográfico composto por 26 fotografias e o passa para três especialistas editá-lo. O resultado são três narrativas diferentes. Com isso, torna-se evidente que a mensagem fotográfica pode passar por uma re-elaboração criativa e formar discursos enunciativos distintos. Ao final, o trabalho mostra que as diferenças entre os discursos elaborados pelos editores são apreendidos pelo receptor da mensagem fotográfica.

  7. Examining the extreme 2017 spring drought event in South Korea using a suite of drought indices (SPI, SC-PDSI, SPEI, EDI)

    Nam, W. H.; Hayes, M. J.; Svoboda, M. D.; Fuchs, B.; Tadesse, T.; Wilhite, D. A.; Hong, E. M.; Kim, T.

    2017-12-01

    South Korea has experienced extreme droughts in 1994-1995, 2000-2001, 2012, 2015, and 2016-2017. The 2017 spring drought (with especially low winter precipitation recorded in winter 2016) affected a large portion of central and western South Korea, and was one of the most severe droughts in the region since the 2000-2001 drought. The spring drought of 2017 was characterized by exceptionally low precipitation with total precipitation from January to June being 50% lower than the mean normal precipitation record (1981-2010) over most of western South Korea. It was the climatologically driest spring over the 1961-2016 record period. Effective drought monitoring and management depends on which drought indices are selected because each drought index has different drought criteria or levels of drought severity, associated with drought responses. In this study, for the quantitative analysis of the spring 2017 drought event in South Korea, four widely-used drought indices, including the Standardized Precipitation Index (SPI), the Standardized Precipitation Evapotranspiration Index (SPEI), the Self-Calibrated Palmer Drought Severity Index (SC-PDSI), and the Effective Drought Index (EDI) are compared with observed drought damaged areas in the context of agricultural drought impacts. The South Korean government (Ministry of Agriculture, Food and Rural Affairs (MAFRA) and Korea Rural Community Corporation (KRC)) has been operating a government-level drought monitoring system since 2016. Results from this study can be used to improve the drought monitoring applications, as well as drought planning and preparedness in South Korea.

  8. Multi Temporal Interferometry as Tool for Urban Landslide Hazard Assessment

    Vicari, A.; Colangelo, G.; Famiglietti, N.; Cecere, G.; Stramondo, S.; Viggiano, D.

    2017-12-01

    Advanced Synthetic Aperture Radar Differential Interferometry (A-DInSAR) are Multi Temporal Interferometry(MTI) techniques suitable for the monitoring of deformation phenomena in slow kinematics. A-DInSAR methodologies include both Coherence-based type, as well as Small Baseline Subset (SBAS) (Berardino et al., 2002, Lanari et al., 2004) and Persistent/Permanent Scatterers (PS), (Ferretti et al., 2001). Such techniques are capable to provide wide-area coverage (thousands of km2) and precise (mm-cm resolution), spatially dense information (from hundreds to thousands of measurementpoints/km2) on groundsurfacedeformations. SBAS and PShavebeenapplied to the town of Stigliano (MT) in Basilicata Region (Southern Italy), where the social center has been destroyed after the reactivation of a known landslide. The comparison of results has shown that these techniques are equivalent in terms of obtained coherent areas and displacement patterns, although lightly different velocity values for individual points (-5/-25 mm/y for PS vs. -5/-15 mm/y for SBAS) have been pointed out. Differences are probably due to scattering properties of the ground surface (e.g. Lauknes et al., 2010). Furthermore, on the crown of the landslide body, a Robotics Explorer Total Monitoring Station (Leica Nova TM50) that measures distance values with 0.6 mm of resolution has been installed. In particular, 20 different points corresponding to that identified through satellite techniques have been chosen, and a sampling time of 15 minutes has been fixed. The displacement values obtained are in agreement with the results of the MTI analysis, showing as these techniques could be a useful tool in the case of early - warning situations.

  9. Self-mixing interferometry: a novel yardstick for mechanical metrology

    Donati, Silvano

    2016-11-01

    A novel configuration of interferometry, SMI (self-mixing interferometry), is described in this paper. SMI is attractive because it doesn't require any optical part external to the laser and can be employed in a variety of measurements - indeed it is sometimes indicated as the "interferometer for measuring without an interferometer". On processing the phase carried by the optical field upon propagation to the target under test, a number of applications have been developed, including traditional measurements related to metrology and mechanical engineering - like displacement, distance, small-amplitude vibrations, attitude angles, velocity, as well as new measurements, like mechanical stress-strain hysterisis and microstructure/MEMS electro-mechanical response. In another field, sensing of motility finds direct application in a variety of biophysical measurements, like blood pulsation, respiratory sounds, chest acoustical impedance, and blood velocity profile. And, we may also look at the amplitude of the returning signal in a SMI, and we can measure weak optical echoes - for return loss and isolation factor measurements, CD readout and scroll sensing, and THz-wave detection. Last, the fine details of the SMI waveform reveal physical parameters of the laser like the laser linewidth, coherence length, and alpha factor. Worth to be noted, SMI is also a coherent detection scheme, and measurement close to the quantum limit of received field with minimum detectable displacements of 100 pm/√Hz are currently achieved upon operation on diffusive targets, whereas in detection mode returning signal can be sensed down to attenuations of -80dB.

  10. CMP reflection imaging via interferometry of distributed subsurface sources

    Kim, D.; Brown, L. D.; Quiros, D. A.

    2015-12-01

    The theoretical foundations of recovering body wave energy via seismic interferometry are well established. However in practice, such recovery remains problematic. Here, synthetic seismograms computed for subsurface sources are used to evaluate the geometrical combinations of realistic ambient source and receiver distributions that result in useful recovery of virtual body waves. This study illustrates how surface receiver arrays that span a limited distribution suite of sources, can be processed to reproduce virtual shot gathers that result in CMP gathers which can be effectively stacked with traditional normal moveout corrections. To verify the feasibility of the approach in practice, seismic recordings of 50 aftershocks following the magnitude of 5.8 Virginia earthquake occurred in August, 2011 have been processed using seismic interferometry to produce seismic reflection images of the crustal structure above and beneath the aftershock cluster. Although monotonic noise proved to be problematic by significantly reducing the number of usable recordings, the edited dataset resulted in stacked seismic sections characterized by coherent reflections that resemble those seen on a nearby conventional reflection survey. In particular, "virtual" reflections at travel times of 3 to 4 seconds suggest reflector sat approximately 7 to 12 km depth that would seem to correspond to imbricate thrust structures formed during the Appalachian orogeny. The approach described here represents a promising new means of body wave imaging of 3D structure that can be applied to a wide array of geologic and energy problems. Unlike other imaging techniques using natural sources, this technique does not require precise source locations or times. It can thus exploit aftershocks too small for conventional analyses. This method can be applied to any type of microseismic cloud, whether tectonic, volcanic or man-made.

  11. Monitoring Seasonal Changes in Permafrost Using Seismic Interferometry

    James, S. R.; Knox, H. A.; Abbott, R. E.

    2015-12-01

    The effects of climate change in polar regions and their incorporation in global climate models has recently become an area of great interest. Permafrost holds entrapped greenhouse gases, e.g. CO2 and CH4, which are released to the atmosphere upon thawing, creating a positive feedback mechanism. Knowledge of seasonal changes in active layer thickness as well as long term degradation of permafrost is critical to the management of high latitude infrastructures, hazard mitigation, and increasing the accuracy of climate predictions. Methods for effectively imaging the spatial extent, depth, thickness, and discontinuous nature of permafrost over large areas are needed. Furthermore, continuous monitoring of permafrost over annual time scales would provide valuable insight into permafrost degradation. Seismic interferometry using ambient seismic noise has proven effective for recording velocity changes within the subsurface for a variety of applications, but has yet to be applied to permafrost studies. To this end, we deployed 7 Nanometrics Trillium posthole broadband seismometers within Poker Flat Research Range, located 30 miles north of Fairbanks, Alaska in a zone of discontinuous permafrost. Approximately 2 years worth of nearly continuous ambient noise data was collected. Using the python package MSNoise, relative changes in velocity were calculated. Results show high amounts of variability throughout the study period. General trends of negative relative velocity shifts can be seen between August and October followed by a positive relative velocity shift between November and February. Differences in relative velocity changes with both frequency and spatial location are also observed, suggesting this technique is sensitive to permafrost variation with depth and extent. Overall, short and long term changes in shallow subsurface velocity can be recovered using this method proposing seismic interferometry is a promising new technique for permafrost monitoring. Sandia

  12. Implementation of time-delay interferometry for LISA

    Tinto, Massimo; Shaddock, Daniel A.; Sylvestre, Julien; Armstrong, J.W.

    2003-01-01

    We discuss the baseline optical configuration for the Laser Interferometer Space Antenna (LISA) mission, in which the lasers are not free-running, but rather one of them is used as the main frequency reference generator (the master) and the remaining five as slaves, these being phase-locked to the master (the master-slave configuration). Under the condition that the frequency fluctuations due to the optical transponders can be made negligible with respect to the secondary LISA noise sources (mainly proof-mass and shot noises), we show that the entire space of interferometric combinations LISA can generate when operated with six independent lasers (the one-way method) can also be constructed with the master-slave system design. The corresponding hardware trade-off analysis for these two optical designs is presented, which indicates that the two sets of systems needed for implementing the one-way method, and the master-slave configuration, are essentially identical. Either operational mode could therefore be implemented without major implications on the hardware configuration. We then derive the required accuracies of armlength knowledge, time synchronization of the onboard clocks, sampling times and time-shifts needed for effectively implementing time-delay interferometry for LISA. We find that an armlength accuracy of about 16 meters, a synchronization accuracy of about 50 ns, and the time jitter due to a presently existing space qualified clock will allow the suppression of the frequency fluctuations of the lasers below to the level identified by the secondary noise sources. A new procedure for sampling the data in such a way to avoid the problem of having time shifts that are not integer multiples of the sampling time is also introduced, addressing one of the concerns about the implementation of time-delay interferometry

  13. Coping with power dispersion?

    2014-01-01

    The last decades have witnessed a significant shift in policy competences away from central governments in Europe. The reallocation of competences spans over three dimensions: upwards; sideways; and downwards. This collection takes the dispersion of powers as a starting point and seeks to assess...... how the actors involved cope with the new configurations. In this introduction, we discuss the conceptualization of power dispersion and highlight the ways in which the contributions add to this research agenda. We then outline some general conclusions and end by indicating future avenues of research....... Taken together, the collection contributes some answers to the challenge of defining and measuring – in a comparative way – the control and co-ordination mechanisms which power dispersion generates. It also explores the tension between political actors' quest for autonomy and the acknowledgement...

  14. Neutron interferometry lessons in experimental quantum mechanics, wave-particle duality, and entanglement

    Rauch, Helmut

    2015-01-01

    The quantum interference of de Broglie matter waves is probably one of the most startling and fundamental aspects of quantum mechanics. It continues to tax our imaginations and leads us to new experimental windows on nature. Quantum interference phenomena are vividly displayed in the wide assembly of neutron interferometry experiments, which have been carried out since the first demonstration of a perfect silicon crystal interferometer in 1974. Since the neutron experiences all four fundamental forces of nature (strong, weak, electromagnetic, and gravitational), interferometry with neutrons provides a fertile testing ground for theory and precision measurements. Many Gedanken experiments of quantum mechanics have become real due to neutron interferometry. Quantum mechanics is a part of physics where experiment and theory are inseparably intertwined. This general theme permeates the second edition of this book. It discusses more than 40 neutron interferometry experiments along with their theoretical motivation...

  15. Kaon versus pion interferometry signatures of quark-gluon plasma formation

    Gyulassy, M.; Padula, S.S.

    1990-01-01

    The advantages of kaon versus pion interferometry as a probe of quark-gluon plasma formation in high energy nuclear collisions are studied by comparing predictions of Lund resonance gas and plasma hydrodynamic models

  16. Physically-Based Interactive Flow Visualization Based on Schlieren and Interferometry Experimental Techniques

    Brownlee, C.; Pegoraro, V.; Shankar, S.; McCormick, Patrick S.; Hansen, C. D.

    2011-01-01

    Understanding fluid flow is a difficult problem and of increasing importance as computational fluid dynamics (CFD) produces an abundance of simulation data. Experimental flow analysis has employed techniques such as shadowgraph, interferometry

  17. Accelerometer for Space Applications Based on Light-Pulse Atom Interferometry, Phase II

    National Aeronautics and Space Administration — We propose to build a compact, high-precision single-axis accelerometer based on atom interferometry that is applicable to operation in space environments. Based on...

  18. Very long baseline interferometry applied to polar motion, relativity, and geodesy. Ph.D. thesis

    Ma, C.

    1978-01-01

    The causes and effects of diurnal polar motion are described. An algorithm was developed for modeling the effects on very long baseline interferometry observables. A selection was made between two three-station networks for monitoring polar motion. The effects of scheduling and the number of sources observed on estimated baseline errors are discussed. New hardware and software techniques in very long baseline interferometry are described

  19. Analysis of reconstructed interference fields in digital holographic interferometry using the polynomial phase transform

    Gorthi, Sai Siva; Rastogi, Pramod

    2009-01-01

    A noisy wrapped phase map is the end-output of commonly employed phase estimation methods in digital holographic interferometry. Hence filtering and unwrapping are necessary to obtain continuous phase distributions. This paper introduces a new approach for phase estimation in digital holographic interferometry using the polynomial phase transform. The proposed approach directly provides an accurate estimation of the unwrapped phase distribution from a noisy reconstructed interference field, thereby bypassing cumbersome and error-prone filtering and 2D phase unwrapping procedures

  20. Precise signal amplitude retrieval for a non-homogeneous diagnostic beam using complex interferometry approach

    Krupka, M.; Kálal, M.; Dostál, Jan; Dudžák, Roman; Juha, Libor

    2017-01-01

    Roč. 12, Aug (2017), s. 1-6, č. článku C08012. ISSN 1748-0221 EU Projects: European Commission(XE) 654148 - LASERLAB-EUROPE Institutional support: RVO:68378271 Keywords : magnetic-field measurements * fully automated-analysis * laser-produced plasmas * image processing * interferometry * plasma diagnostics - interferometry * spectroscopy and imaging Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.220, year: 2016

  1. Potential of the McMath-Pierce 1.6-Meter Solar Telescope for Speckle Interferometry

    Harshaw, Richard; Jones, Gregory; Wiley, Edward; Boyce, Patrick; Branston, Detrick; Rowe, David; Genet, Russell

    2015-09-01

    We explored the aiming and tracking accuracy of the McMath-Pierce 1.6 m solar telescope at Kitt Peak National Observatory as part of an investigation of using this telescope for speckle interferometry of close visual double stars. Several slews of various lengths looked for hysteresis in the positioning system (we found none of significance) and concluded that the 1.6 m telescope would make a useful telescope for speckle interferometry.

  2. Beam-modulation methods in quantitative and flow-visualization holographic interferometry

    Decker, Arthur J.

    1986-01-01

    Heterodyne holographic interferometry and time-average holography with a frequency shifted reference beam are discussed. Both methods will be used for the measurement and visualization of internal transonic flows where the target facility is a flutter cascade. The background and experimental requirements for both methods are reviewed. Measurements using heterodyne holographic interferometry are presented. The performance of the laser required for time-average holography of time-varying transonic flows is discussed.

  3. Beam-modulation methods in quantitative and flow visualization holographic interferometry

    Decker, A.

    1986-01-01

    This report discusses heterodyne holographic interferometry and time-average holography with a frequency shifted reference beam. Both methods will be used for the measurement and visualization of internal transonic flows, where the target facility is a flutter cascade. The background and experimental requirements for both methods are reviewed. Measurements using heterodyne holographic interferometry are presented. The performance of the laser required for time-average holography of time-varying transonic flows is discussed.

  4. Interface, a dispersed architecture

    Vissers, C.A.

    1976-01-01

    Past and current specification techniques use timing diagrams and written text to describe the phenomenology of an interface. This paper treats an interface as the architecture of a number of processes, which are dispersed over the related system parts and the message path. This approach yields a

  5. Psychorheology of food dispersions

    Štern, Petr; Panovská, Z.; Pokorný, J.

    2010-01-01

    Roč. 58, č. 1 (2010), s. 29-35 ISSN 0042-790X R&D Projects: GA AV ČR IAA2060404 Institutional research plan: CEZ:AV0Z20600510 Keywords : psychorheology * food dispersions * tomato ketchup * rheology * sensory analysis Subject RIV: BK - Fluid Dynamics Impact factor: 0.553, year: 2010

  6. Dispersal of sticky particles

    Reddy, Ramana; Kumar, Sanjeev

    2007-12-01

    In this paper, we show through simulations that when sticky particles are broken continually, particles are dispersed into fine dust only if they are present in a narrow range of volume fractions. The upper limit of this range is 0.20 in the 2D and 0.10 in the 3D space. An increase in the dimensionality of space reduces the upper limit nearly by a factor of two. This scaling holds for dispersal of particles in hyperdimensional space of dimensions up to ten, the maximum dimension studied in this work. The maximum values of volume fractions obtained are significantly lower than those required for close packing and random packing of discs in 2D and spheres in 3D space. These values are also smaller than those required for critical phenomena of cluster percolation. The results obtained are attributed to merger cascades of sticky particles, triggered by breakup events. A simple theory that incorporates this cascade is developed to quantitatively explain the observed scaling of the upper limit with the dimensionality of space. The theory also captures the dynamics of the dispersal process in the corresponding range of particle volume fractions. The theory suggests that cascades of order one and two predominantly decide the upper limit for complete dispersal of particles.

  7. Application of seismic interferometry to an exploration of subsurface structure by using microtremors. Estimation of deep ground structures in the Wakasa bay region

    Sato, Hiroaki; Kuriyama, Masayuki; Higashi, Sadanori; Shiba, Yoshiaki; Okazaki, Atsushi

    2015-01-01

    We carried out continuous measurements of microtremors to synthesize Green's function based on seismic interferometry in order to estimate deep subsurface structures of the Ohshima peninsula (OSM) and the Otomi peninsula (OTM) in the Wakasa bay region. Using more than 80 days of data, dispersive waveforms in the cross correlations were identified as a Green's function based on seismic interferometry. Rayleigh-wave phase velocities at OSM and OTM were estimated by two different method using microtremors: first, by analyzing microtremor array data, and second, by applying the f-k spectral analysis to synthesized Green's functions derived from cross-correlation with a common observation station. Relatively longer period of phase velocities were estimated by the f-k spectral analysis using the synthesized Green's functions with a common observation station. This suggests that the synthesized Green's functions from seismic interferometry can provide a valuable data for phase velocity inversion to estimate a deep subsurface structure. By identifying deep subsurface structures at OSM and OTM based on an inversion of phase velocity from both methods, the depth of S wave velocity of about 3.5 km/s, considered as a top of seismogenic layer, were determined to be 3.8 - 4.0 km at OSM and 4.4 - 4.6 km at OTM, respectively. Love- and Rayleigh-wave group velocities were estimated from the multiple filtering analysis of the synthesized Green's functions. From the comparison of observed surface wave group velocities and theoretical group velocities of OSM and OTM, we demonstrated that the observed group velocities were in good agreement with the average of theoretical group velocities calculated by identified deep subsurface structures at OSM and OTM. It is suggested that the deep subsurface structure of the shallow sea region between two peninsulas is continuous structure from OSM to OTM and that Love- and Rayleigh-wave group velocities using

  8. Assessing ScanSAR Interferometry for Deformation Studies

    Buckley, S. M.; Gudipati, K.

    2007-12-01

    There is a trend in civil satellite SAR mission design to implement an imaging strategy that incorporates both stripmap mode and ScanSAR imaging. This represents a compromise between high resolution data collection and a desire for greater spatial coverage and more frequent revisit times. However, mixed mode imaging can greatly reduce the number of stripmap images available for measuring subtle ground deformation. Although ScanSAR-ScanSAR and ScanSAR-stripmap repeat-pass interferometry have been demonstrated, these approaches are infrequently used for single interferogram formation and nonexistent for InSAR time series analysis. For future mission design, e.g., a dedicated US InSAR mission, the effect of various ScanSAR system parameter choices on InSAR time series analysis also remains unexplored. Our objective is to determine the utility of ScanSAR differential interferometry. We will demonstrate the use of ScanSAR interferograms for several previous deformation studies: localized and broad-scale urban land subsidence, tunneling, volcanic surface movements and several examples associated with the seismic cycle. We also investigate the effect of various ScanSAR burst synchronization levels on our ability to detect and make quality measurements of deformation. To avoid the issues associated with Envisat ScanSAR burst alignment and to exploit a decade of InSAR measurements, we simulate ScanSAR data by bursting (throwing away range lines of) ERS-1/2 data. All the burst mode datasets are processed using a Modified SPECAN algorithm. To investigate the effects of burst misalignment, a number of cases with varying degrees of burst overlap are considered. In particular, we look at phase decorrelation as a function of percentage of burst overlap. Coherence clearly reduces as the percentage of overlap decreases and we find a useful threshold of 40-70% burst overlap depending on the study site. In order to get a more generalized understanding for different surface conditions

  9. Seeing Stars - Intensity Interferometry in the Laboratory & on the Ground

    Carlile, Colin; Dravins, Dainis

    2018-04-01

    In many ways it is a golden age for astronomy. Spectacular new discoveries, for example the detection of gravitational waves, are very dependent upon instrumental development. The specific instrument development we propose, Intensity Interferometry (II), aims toimprove the spatial resolution of optical telescopes by 100x to 50µas [1]. This is impractical to achieve by increasing the size of telescopes or by extending the capabilities of phase interferometry. II, if implemented on the Cherenkov Telescope Array (CTA) currently being installed in La Palma and Paranal, would record the light intensity – the photon train - from many different telescopes, up to 2 km apart, on a nanosecond timescale and compare them. The signal from the many pairs of telescopes would quantify the degree of correlation by extracting the second-order correlation function, and thus create an image. This is not a real space image. However we can invert the data by Fourier Transform and create a real image. The more telescopes, the better resolved and more physical is the image, enabling the study of sunspots on nearby stars; orbiting binary stars; or exoplanets traversing the disc of their own star. We understand the Sun well but we have little experimental knowledge of how representative it is of main sequence stars. To test the II method, at Lund Observatory we have set up a laboratory analogue comprising ten small telescopes observing an artificial star created by light from a laser. The method has been shown to work [2] and the telescope array has now been extended to two dimensions. We are in discussion with other groups to explore the possibility of implementing this method on real telescopes observing actual stars. We plan to do this with the prototype Small Size Telescopes being built by groups in Europe, and ultimately with the CTA itself. A Science Working Group for II has now been set up within the CTA Consortium, of which Lund University is an integral part. A Letter of Intent

  10. Carta do editor de edições especiais da Encontros Bibli 10.5007/1518-2924.2011v16nesp1piv

    Francisco das Chagas de Souza

    2011-06-01

    Full Text Available Dos horizontes arquivísticos e de seu sentido É significativo observar que a discussão sobre Arquivologia e sobre as práticas profissionais arquivisticas tem avançado muito nos últimos anos no Brasil, e as razões são claramente apontadas pelos organizadores desta edição especial de Encontros Bibli em seu texto editorial. Contendo sete artigos, esta edição temática traz o título Horizontes Arquivísticos.Para dar vida a este número, foi desenvolvido um trabalho de quase dois anos, liderado pelo pesquisador José Maria Jardim e colaboração de Renata Silva Borges. Aqui estão reunidos nove autores e seis avaliadores, todos vinculados a instituições de ensino e de pesquisa ligadas ao Serviço Público Federal, com sede nas cidades de Brasilia, Rio de Janeiro, Niteroi e Florianópolis: UNB, UNIRIO, UFF, UFRJ, UFSC, Arquivo Nacional e FIOCRUZ.Neste momento da história brasileira ─ em que se anunciam políticas governamentais em prol da cidadania, em que se diz da disposição de resgate da verdade sobre os fatos políticos acontecidos na gestão do estado brasileiro dos anos de 1964 a 1989 ─ os arquivos e seus profissionais passam a divisar um relevante protagonismo. Pode-se dizer que, de certa maneira, deu-se um movimento de preparação deste protagonismo e que, simultaneamente, essa preparação alicerçou a percepção de segmentos importantes do setor público para oferecer essa perspectiva para a sociedade nacional.Nesse sentido, tem peso relevante a instalação de novos cursos de bacharelado na área, totalizando, em 2011, o número de 14 universidades que os oferecem: UNIRIO, UFF, UFSM, UFES, UNB, UEL, UFBA ,UNESP/MARÍLIA, UFRGS, UEPB, UFAM, FURG, UFMG, UFSC. Uma nota marcante é que todas essas Instituições de Ensino Superior têm vínculos governamentais, sendo onze federais e três estaduais. Esse movimento não se faz por outro caminho senão o da pesquisa histórica e social. Em áreas como a História, Educa

  11. Novel methods for matter interferometry with nanosized objects

    Arndt, Markus

    2005-05-01

    We discuss the current status and prospects for novel experimental methods for coherence^1,2 and decoherence^3 experiments with large molecules. Quantum interferometry with nanosized objects is interesting for the exploration of the quantum-classical transition. The same experimental setup is also promising for metrology applications and molecular nanolithography. Our coherence experiments with macromolecules employ a Talbot-Lau interferometer. We discuss some modifications to this scheme, which are required to extend it to particles with masses in excess of several thousand mass units. In particular, the detection in all previous interference experiments with large clusters and molecules, was based on either laser ionization^1 (e.g. Fullerenes) or electron impact ionization^2 (e.g. Porphyrins etc.). However, most ionization schemes run into efficiency limits when the mass and complexity of the target particle increases. Here we present experimental results for an interference detector which is truly scalable, i.e. one which will even improve with increasing particle size and complexity. ``Mechanically magnified fluorescence imaging'' (MMFI), combines the high spatial resolution, which is intrinsic to Talbot Lau interferometry with the high detection efficiency of fluorophores adsorbed onto a substrate. In the Talbot Lau setup a molecular interference pattern is revealed by scanning the 3^rd grating across the molecular beam^1. The number of transmitted molecules is a function of the relative position between the mask and the molecular density pattern. Both the particle interference pattern and the mechanical mask structure may be far smaller than any optical resolution limit. After mechanical magnification by an arbitrary factor, in our case a factor 5000, the interference pattern can still be inspected in fluorescence microscopy. The fluorescent molecules are collected on a surface which is scanned collinearly and synchronously behind the 3rd grating. The

  12. Laser Micromachining and Information Discovery Using a Dual Beam Interferometry

    Theppakuttaikomaraswamy, Senthil P. [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Lasers have proven to be among the most promising tools for micromachining because they can process features down to the size of the laser wavelength (smaller than 1 micrometer) and they provide a non-contact technology for machining. The demand for incorporating in-situ diagnostics technology into the micromachining environment is driven by the increasing need for producing micro-parts of high quality and accuracy. Laser interferometry can be used as an on-line monitoring tool and it is the aim of this work to enhance the understanding and application of Michelson interferometry principle for the in-situ diagnostics of the machining depth on the sub-micron and micron scales. micromachining is done on two different materials and a comprehensive investigation is done to control the width and depth of the machined feature. To control the width of the feature, laser micromachining is done on copper and a detailed analysis is performed. The objective of this experiment is to make a precision mask for sputtering with an array of holes on it using an Nd:YAG laser of 532 nm wavelength. The diameter of the hole is 50 μm and the spacing between holes (the distance between the centers) is 100 μm. Michelson interferometer is integrated with a laser machining system to control the depth of machining. An excimer laser of 308 nm wavelength is used for micromachining. A He-Ne laser of 632.8 nm wavelength is used as the light source for the interferometer. Interference patterns are created due to the change in the path length between the two interferometer arms. The machined depth information is obtained from the interference patterns on an oscilloscope detected by a photodiode. To compare the predicted depth by the interferometer with the true machining depth, a surface profilometer is used to measure the actual machining depth on the silicon. It is observed that the depths of machining obtained by the surface profile measurement are in accordance with the interferometer

  13. Nonlinear Kalman filters for calibration in radio interferometry

    Tasse, C.

    2014-06-01

    The data produced by the new generation of interferometers are affected by a wide variety of partially unknown complex effects such as pointing errors, phased array beams, ionosphere, troposphere, Faraday rotation, or clock drifts. Most algorithms addressing direction-dependent calibration solve for the effective Jones matrices, and cannot constrain the underlying physical quantities of the radio interferometry measurement equation (RIME). A related difficulty is that they lack robustness in the presence of low signal-to-noise ratios, and when solving for moderate to large numbers of parameters they can be subject to ill-conditioning. These effects can have dramatic consequences in the image plane such as source or even thermal noise suppression. The advantage of solvers directly estimating the physical terms appearing in the RIME is that they can potentially reduce the number of free parameters by orders of magnitudes while dramatically increasing the size of usable data, thereby improving conditioning. We present here a new calibration scheme based on a nonlinear version of the Kalman filter that aims at estimating the physical terms appearing in the RIME. We enrich the filter's structure with a tunable data representation model, together with an augmented measurement model for regularization. Using simulations we show that it can properly estimate the physical effects appearing in the RIME. We found that this approach is particularly useful in the most extreme cases such as when ionospheric and clock effects are simultaneously present. Combined with the ability to provide prior knowledge on the expected structure of the physical instrumental effects (expected physical state and dynamics), we obtain a fairly computationally cheap algorithm that we believe to be robust, especially in low signal-to-noise regimes. Potentially, the use of filters and other similar methods can represent an improvement for calibration in radio interferometry, under the condition that

  14. Applications of atom interferometry - from ground to space

    Schubert, Christian; Rasel, Ernst Maria; Gaaloul, Naceur; Ertmer, Wolfgang

    2016-07-01

    Atom interferometry is utilized for the measurement of rotations [1], accelerations [2] and for tests of fundamental physics [3]. In these devices, three laser light pulses separated by a free evolution time coherently manipulate the matter waves which resembles the Mach-Zehnder geometry in optics. Atom gravimeters demonstrated an accuracy of few microgal [2,4], and atom gradiometers showed a noise floor of 30 E Hz^{-1/2} [5]. Further enhancements of atom interferometers are anticipated by the integration of novel source concepts providing ultracold atoms, extending the free fall time of the atoms, and enhanced techniques for coherent manipulation. Sources providing Bose-Einstein condensates recently demontrated a flux compatible with precision experiments [6]. All of these aspects are studied in the transportable quantum gravimeter QG-1 and the very long baseline atom interferometry teststand in Hannover [7] with the goal of surpassing the microgal regime. Going beyond ground based setups, the QUANTUS collaboration exploits the unique features of a microgravity environment in drop tower experiments [8] and in a sounding rocket mission. The payloads are compact and robust atom optics experiments based on atom chips [6], enabling technology for transportable sensors on ground as a byproduct. More prominently, they are pathfinders for proposed satellite missions as tests of the universality of free fall [9] and gradiometry based on atom interferometers [10]. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM1552-1557 (QUANTUS-IV-Fallturm) and by the Deutsche Forschungsgemeinschaft in the framework of the SFB 1128 geo-Q. [1] PRL 114 063002 2015 [2] Nature 400 849 1999 [3] PRL 112 203002 2014 [4] NJP 13 065026 2011 [5] PRA 65 033608 2002 [6] NJP 17 065001 2015 [7] NJP 17 035011 2015 [8] PRL 110 093602 2013 [9

  15. Prosthetic clone and natural human tooth comparison by speckle interferometry

    Slangen, Pierre; Corn, Stephane; Fages, Michel; Raynal, Jacques; Cuisinier, Frederic J. G.

    2010-09-01

    New trends in dental prosthodontic interventions tend to preserve the maximum of "body" structure. With the evolution of CAD-CAM techniques, it is now possible to measure "in mouth" the remaining dental tissues. The prosthetic crown is then designed using this shape on which it will be glued on, and also by taking into account the contact surface of the opposite jaw tooth. Several theories discuss on the glue thickness and formulation, but also on the way to evolve to a more biocompatible crown and also new biomechanical concepts. In order to validate these new concepts and materials, and to study the mechanical properties and mechanical integrity of the prosthesis, high resolution optical measurements of the deformations of the glue and the crown are needed. Samples are two intact premolars extracted for orthodontics reasons. The reference sample has no modifications on the tooth while the second sample tooth is shaped to receive a feldspathic ceramic monoblock crown which will be glued. This crown was manufactured with a chairside CAD-CAM system from an intra-oral optical print. The software allows to realize a nearly perfect clone of the reference sample. The necessary space for the glue is also entered with ideal values. This duplication process yields to obtain two samples with identical anatomy for further processing. The glue joint thickness can also be modified if required. The purpose is to compare the behaviour of a natural tooth and its prosthetic clone manufactured with "biomechanical" concepts. Vertical cut samples have been used to deal with planar object observation, and also to look "inside" the tooth. We have developed a complete apparatus enabling the study of the compressive mechanical behaviour of the concerned tooth by speckle interferometry. Because in plane displacements are of great interest for orthodontic measurements1, an optical fiber in-plane sensitive interferometer has been designed. The fibers are wrapped around piezoelectric

  16. Dispersed flow film boiling

    Andreani, M.; Yadigaroglu, G.

    1989-12-01

    Dispersed flow film boiling is the heat transfer regime that occurs at high void fractions in a heated channel. The way this transfer mode is modelled in the NRC computer codes (RELAP5 and TRAC) and the validity of the assumption and empirical correlations used is discussed. An extensive review of the theoretical and experimental work related with heat transfer to highly dispersed mixtures reveals the basic deficiencies of these models: the investigation refers mostly to the typical conditions of low rate bottom reflooding, since the simulation of this physical situation by the computer codes has often showed poor results. The alternative models that are available in the literature are reviewed, and their merits and limits are highlighted. The modification that could improve the physics of the models implemented in the codes are identified. (author) 13 figs., 123 refs

  17. Working document dispersion models

    Dop, H. van

    1988-01-01

    This report is a summary of the most important results from June 1985 of the collaboration of the RIVM (Dutch National Institute for Public Health and Environment Hygiene) and KNMI (Royal Dutch Meteorologic Institute) on the domain of dispersion models. It contains a short description of the actual SO x /NO x -model. Furthermore it contains recommendations for modifications of some numerical-mathematical aspects and an impulse to a more complete description of chemical processes in the atmosphere and the (wet) deposition process. A separate chapter is devoted to the preparation of meteorologic data which are relevant for dispersion as well as atmospheric chemistry and deposition. This report serves as working document for the final formulation of a acidifying- and oxidant-model. (H.W.). 69 refs.; 51 figs.; 13 tabs.; 3 schemes

  18. Spatially Dispersed Employee Recovery

    Hvass, Kristian Anders; Torfadóttir, Embla

    2014-01-01

    Employee recovery addresses either employee well-being or management's practices in aiding employees in recovering themselves following a service failure. This paper surveys the cabin crew at a small, European, low-cost carrier and investigates employees' perceptions of management practices to aid...... personnel achieve service recovery. Employee recovery within service research often focuses on front-line employees that work in a fixed location, however a contribution to the field is made by investigating the recovery of spatially dispersed personnel, such as operational personnel in the transport sector......, who have a work place away from a fixed or central location and have minimal management contact. Results suggest that the support employees receive from management, such as recognition, information sharing, training, and strategic awareness are all important for spatially dispersed front...

  19. Heat dispersion in rivers

    Shaw, T.L.

    1974-01-01

    One of the tasks of the Sonderforschungsbereich 80 is to study the dispersion of heat discharged into rivers and other bodies of water and to develop methods which permit prediction of detrimental effects caused by the heated discharges. In order to help the SFB 80 to specify this task, Dr. Shaw, lecturer of Civil Engineering at the Bristol University, conducted a literature survey on heat-dispersion studies during the two months which he spent as a visiting research fellow with the SFB 80 at the University of Karlsruhe in the summer of 1973. The following report is the outcome of this survey. It gives Dr. Shaw's assessment of the present state of knowledge - based almost exclusively on literature in the English language - and compares this with the knowledge required by river planners. The apparent discrepancy leads to suggestions for future research. Selected references as well as a representative bibliography can be found at the end of the report. (orig.) [de

  20. Taylor dispersion of nanoparticles

    Balog, Sandor; Urban, Dominic A.; Milosevic, Ana M.; Crippa, Federica; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

    2017-08-01

    The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical extinction, translational diffusion, and sheer-enhanced dispersion of nanoparticles subjected to a steady laminar flow. The interplay of these defines the apparent size. Considering that particles in fact are never truly uniform nor monodisperse, we rigorously address particle polydispersity and calculate the apparent particle size measured by Taylor dispersion analysis. We conducted case studies addressing aqueous suspensions of model particles and large-scale-produced "industrial" particles of both academic and commercial interest of various core materials and sizes, ranging from 15 to 100 nm. A comparison with particle sizes determined by transmission electron microscopy confirms that our approach is model-independent, non-parametric, and of general validity that provides an accurate account of size polydispersity—independently on the shape of the size distribution and without any assumption required a priori.

  1. Precision displacement interferometry with stabilization of wavelength on air

    Buchta Z.

    2013-05-01

    Full Text Available We present an interferometric technique based on differential interferometry setup for measurement in the subnanometer scale in atmospheric conditions. The motivation for development of this ultraprecise technique is coming from the field of nanometrology. The key limiting factor in any optical measurement are fluctuations of the refractive index of air representing a source of uncertainty on the 10-6level when evaluated indirectly from the physical parameters of the atmosphere. Our proposal is based on the concept of overdetermined interferometric setup where a reference length is derived from a mechanical frame made from a material with very low thermal coefficient on the 10-8level. The technique allows to track the variations of the refractive index of air on-line directly in the line of the measuring beam and to compensate for the fluctuations. The optical setup consists of three interferometers sharing the same beam path where two measure differentially the displacement while the third represents a reference for stabilization of the wavelength of the laser source. The principle is demonstrated on an experimental setup and a set of measurements describing the performance is presented.

  2. Atom interferometry in space: Thermal management and magnetic shielding

    Milke, Alexander; Kubelka-Lange, André; Gürlebeck, Norman, E-mail: norman.guerlebeck@zarm.uni-bremen.de; Rievers, Benny; Herrmann, Sven [Center of Applied Space Technology and Microgravity (ZARM), University Bremen, Am Fallturm, 28359 Bremen (Germany); Schuldt, Thilo [DLR Institute for Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Braxmaier, Claus [Center of Applied Space Technology and Microgravity (ZARM), University Bremen, Am Fallturm, 28359 Bremen (Germany); DLR Institute for Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany)

    2014-08-15

    Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 × 10{sup −4} % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 10{sup 5}. We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space.

  3. Development of a Multi-Point Microwave Interferometry (MPMI) Method

    Specht, Paul Elliott [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Marcia A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jilek, Brook Anton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    A multi-point microwave interferometer (MPMI) concept was developed for non-invasively tracking a shock, reaction, or detonation front in energetic media. Initially, a single-point, heterodyne microwave interferometry capability was established. The design, construction, and verification of the single-point interferometer provided a knowledge base for the creation of the MPMI concept. The MPMI concept uses an electro-optic (EO) crystal to impart a time-varying phase lag onto a laser at the microwave frequency. Polarization optics converts this phase lag into an amplitude modulation, which is analyzed in a heterodyne interfer- ometer to detect Doppler shifts in the microwave frequency. A version of the MPMI was constructed to experimentally measure the frequency of a microwave source through the EO modulation of a laser. The successful extraction of the microwave frequency proved the underlying physical concept of the MPMI design, and highlighted the challenges associated with the longer microwave wavelength. The frequency measurements made with the current equipment contained too much uncertainty for an accurate velocity measurement. Potential alterations to the current construction are presented to improve the quality of the measured signal and enable multiple accurate velocity measurements.

  4. Multi - band Persistent Scatterer Interferometry data integration for landslide analysis

    Bianchini, Silvia; Mateos, Rosa; Mora, Oscar; García, Inma; Sánchez, Ciscu; Sanabria, Margarita; López, Maite; Mulas, Joaquin; Hernández, Mario; Herrera, Gerardo

    2013-04-01

    We present a methodology to perform a geomorphological assessment of ground movements over wide areas, by improving Persistent Scatterer Interferometry (PSI) analysis for landslide studies. The procedure relies on the integrated use of multi-band EO data acquired by different satellite sensors in different time intervals, to provide a detailed investigation of ground displacements. The methodology, throughout the cross-comparison and integration of PS data in different microwave bands (ALOS in L-band, ERS1/2 and ENVISAT in C-band, COSMOSKY-MED in X-band), is applied on the Tramontana Range in the northwestern part of Mallorca island (Spain), extensively affected by mass movements across time, especially during the last years. We increase the confidence degree of the available interferometric data and we homogenize all PS targets by implementing and classifying them through common criteria. Therefore, PSI results are combined with geo-thematic data and pre-existing landslide inventories of the study area, in order to improve the landslide database, providing additional information on the detected ground displacements. The results of this methodology are used to elaborate landslide activity maps, permitting to jointly exploit heterogeneous PS data for analyzing landslides at regional scale. Moreover, from a geomorphological perspective, the proposed approach exploits the implemented PS data to achieve a reliable spatial analysis of movement rates, whatever referred to certain landslide phenomena or to other natural processes, in order to perform ground motion activity maps within a wide area.

  5. Spaceborne Differential SAR Interferometry: Data Analysis Tools for Deformation Measurement

    Michele Crosetto

    2011-02-01

    Full Text Available This paper is focused on spaceborne Differential Interferometric SAR (DInSAR for land deformation measurement and monitoring. In the last two decades several DInSAR data analysis procedures have been proposed. The objective of this paper is to describe the DInSAR data processing and analysis tools developed at the Institute of Geomatics in almost ten years of research activities. Four main DInSAR analysis procedures are described, which range from the standard DInSAR analysis based on a single interferogram to more advanced Persistent Scatterer Interferometry (PSI approaches. These different procedures guarantee a sufficient flexibility in DInSAR data processing. In order to provide a technical insight into these analysis procedures, a whole section discusses their main data processing and analysis steps, especially those needed in PSI analyses. A specific section is devoted to the core of our PSI analysis tools: the so-called 2+1D phase unwrapping procedure, which couples a 2D phase unwrapping, performed interferogram-wise, with a kind of 1D phase unwrapping along time, performed pixel-wise. In the last part of the paper, some examples of DInSAR results are discussed, which were derived by standard DInSAR or PSI analyses. Most of these results were derived from X-band SAR data coming from the TerraSAR-X and CosmoSkyMed sensors.

  6. Atmospheric pressure loading parameters from very long baseline interferometry observations

    Macmillan, D. S.; Gipson, John M.

    1994-01-01

    Atmospheric mass loading produces a primarily vertical displacement of the Earth's crust. This displacement is correlated with surface pressure and is large enough to be detected by very long baseline interferometry (VLBI) measurements. Using the measured surface pressure at VLBI stations, we have estimated the atmospheric loading term for each station location directly from VLBI data acquired from 1979 to 1992. Our estimates of the vertical sensitivity to change in pressure range from 0 to -0.6 mm/mbar depending on the station. These estimates agree with inverted barometer model calculations (Manabe et al., 1991; vanDam and Herring, 1994) of the vertical displacement sensitivity computed by convolving actual pressure distributions with loading Green's functions. The pressure sensitivity tends to be smaller for stations near the coast, which is consistent with the inverted barometer hypothesis. Applying this estimated pressure loading correction in standard VLBI geodetic analysis improves the repeatability of estimated lengths of 25 out of 37 baselines that were measured at least 50 times. In a root-sum-square (rss) sense, the improvement generally increases with baseline length at a rate of about 0.3 to 0.6 ppb depending on whether the baseline stations are close to the coast. For the 5998-km baseline from Westford, Massachusetts, to Wettzell, Germany, the rss improvement is about 3.6 mm out of 11.0 mm. The average rss reduction of the vertical scatter for inland stations ranges from 2.7 to 5.4 mm.

  7. Enhancing core-diffracted arrivals by supervirtual interferometry

    Bharadwaj, P.

    2013-12-03

    A supervirtual interferometry (SVI) method is presented that can enhance the signal-to-noise ratio (SNR) of core diffracted waveforms by as much as O( √ N), where N is the number of inline receivers that record the core-mantle boundary (CMB) diffractions from more than one event. Here, the events are chosen to be approximately inline with the receivers along the same great circle. Results with synthetic and teleseismic data recorded by USArray stations demonstrate that formerly unusable records with low SNR can be transformed to high SNR records with clearly visible CMB diffractions. Another benefit is that SVI allows for the recording of a virtual earthquake at stations not deployed during the time of the earthquake. This means that portable arrays such as USArray can extend the aperture of one recorded earthquake from the West coast to the East coast, even though the teleseism might have only been recorded during theWest coast deployment. In summary, SVI applied to teleseismic data can significantly enlarge the catalogue of usable records both in SNR and available aperture for analysing CMB diffractions. A potential drawback of this method is that it generally provides the correct kinematics of CMB diffractions, but does not necessarily preserve correct amplitude information. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society.

  8. Synthetic LISA: Simulating time delay interferometry in a model LISA

    Vallisneri, Michele

    2005-01-01

    We report on three numerical experiments on the implementation of Time-Delay Interferometry (TDI) for LISA, performed with Synthetic LISA, a C++/Python package that we developed to simulate the LISA science process at the level of scientific and technical requirements. Specifically, we study the laser-noise residuals left by first-generation TDI when the LISA armlengths have a realistic time dependence; we characterize the armlength-measurement accuracies that are needed to have effective laser-noise cancellation in both first- and second-generation TDI; and we estimate the quantization and telemetry bitdepth needed for the phase measurements. Synthetic LISA generates synthetic time series of the LISA fundamental noises, as filtered through all the TDI observables; it also provides a streamlined module to compute the TDI responses to gravitational waves according to a full model of TDI, including the motion of the LISA array and the temporal and directional dependence of the armlengths. We discuss the theoretical model that underlies the simulation, its implementation, and its use in future investigations on system-characterization and data-analysis prototyping for LISA

  9. Mesospheric gravity wave momentum flux estimation using hybrid Doppler interferometry

    A. J. Spargo

    2017-06-01

    Full Text Available Mesospheric gravity wave (GW momentum flux estimates using data from multibeam Buckland Park MF radar (34.6° S, 138.5° E experiments (conducted from July 1997 to June 1998 are presented. On transmission, five Doppler beams were symmetrically steered about the zenith (one zenith beam and four off-zenith beams in the cardinal directions. The received beams were analysed with hybrid Doppler interferometry (HDI (Holdsworth and Reid, 1998, principally to determine the radial velocities of the effective scattering centres illuminated by the radar. The methodology of Thorsen et al. (1997, later re-introduced by Hocking (2005 and since extensively applied to meteor radar returns, was used to estimate components of Reynolds stress due to propagating GWs and/or turbulence in the radar resolution volume. Physically reasonable momentum flux estimates are derived from the Reynolds stress components, which are also verified using a simple radar model incorporating GW-induced wind perturbations. On the basis of these results, we recommend the intercomparison of momentum flux estimates between co-located meteor radars and vertical-beam interferometric MF radars. It is envisaged that such intercomparisons will assist with the clarification of recent concerns (e.g. Vincent et al., 2010 of the accuracy of the meteor radar technique.

  10. Multiwavelength interferometry system for the Orion laser facility.

    Patankar, S; Gumbrell, E T; Robinson, T S; Lowe, H F; Giltrap, S; Price, C J; Stuart, N H; Kemshall, P; Fyrth, J; Luis, J; Skidmore, J W; Smith, R A

    2015-12-20

    We report on the design and testing of a multiwavelength interferometry system for the Orion laser facility based upon the use of self-path matching Wollaston prisms. The use of UV corrected achromatic optics allows for both easy alignment with an eye-safe light source and small (∼ millimeter) offsets to the focal lengths between different operational wavelengths. Interferograms are demonstrated at wavelengths corresponding to first, second, and fourth harmonics of a 1054 nm Nd:glass probe beam. Example data confirms the broadband achromatic capability of the imaging system with operation from the UV (263 nm) to visible (527 nm) and demonstrates that features as small as 5 μm can be resolved for object sizes of 15 by 10 mm. Results are also shown for an off-harmonic wavelength that will underpin a future capability. The primary optics package is accommodated inside the footprint of a ten-inch manipulator to allow the system to be deployed from a multitude of viewing angles inside the 4 m diameter Orion target chamber.

  11. Mesospheric gravity wave momentum flux estimation using hybrid Doppler interferometry

    Spargo, Andrew J.; Reid, Iain M.; MacKinnon, Andrew D.; Holdsworth, David A.

    2017-06-01

    Mesospheric gravity wave (GW) momentum flux estimates using data from multibeam Buckland Park MF radar (34.6° S, 138.5° E) experiments (conducted from July 1997 to June 1998) are presented. On transmission, five Doppler beams were symmetrically steered about the zenith (one zenith beam and four off-zenith beams in the cardinal directions). The received beams were analysed with hybrid Doppler interferometry (HDI) (Holdsworth and Reid, 1998), principally to determine the radial velocities of the effective scattering centres illuminated by the radar. The methodology of Thorsen et al. (1997), later re-introduced by Hocking (2005) and since extensively applied to meteor radar returns, was used to estimate components of Reynolds stress due to propagating GWs and/or turbulence in the radar resolution volume. Physically reasonable momentum flux estimates are derived from the Reynolds stress components, which are also verified using a simple radar model incorporating GW-induced wind perturbations. On the basis of these results, we recommend the intercomparison of momentum flux estimates between co-located meteor radars and vertical-beam interferometric MF radars. It is envisaged that such intercomparisons will assist with the clarification of recent concerns (e.g. Vincent et al., 2010) of the accuracy of the meteor radar technique.

  12. Multi-static MIMO along track interferometry (ATI)

    Knight, Chad; Deming, Ross; Gunther, Jake

    2016-05-01

    Along-track interferometry (ATI) has the ability to generate high-quality synthetic aperture radar (SAR) images and concurrently detect and estimate the positions of ground moving target indicators (GMTI) with moderate processing requirements. This paper focuses on several different ATI system configurations, with an emphasis on low-cost configurations employing no active electronic scanned array (AESA). The objective system has two transmit phase centers and four receive phase centers and supports agile adaptive radar behavior. The advantages of multistatic, multiple input multiple output (MIMO) ATI system configurations are explored. The two transmit phase centers can employ a ping-pong configuration to provide the multistatic behavior. For example, they can toggle between an up and down linear frequency modulated (LFM) waveform every other pulse. The four receive apertures are considered in simple linear spatial configurations. Simulated examples are examined to understand the trade space and verify the expected results. Finally, actual results are collected with the Space Dynamics Laboratorys (SDL) FlexSAR system in diverse configurations. The theory, as well as the simulated and actual SAR results, are presented and discussed.

  13. X-ray laser interferometry: A new tool for AGEX

    Wan, A.S.; Moreno, J.C.; Libby, S.B.

    1995-10-01

    Collisionally pumped soft x-ray lasers now operate over a wavelength range extending from 4--40 nm. With the recent advances in the development of multilayer mirrors and beamsplitters in the soft x-ray regime, we can utilize the unique properties of x-ray lasers to study large, rapidly evolving laser-driven plasmas with high electron densities. By employing a shorter wavelength x-ray laser, as compared to using conventional optical laser as the probe source, we can access a much higher density regime while reducing refractive effects which limit the spatial resolution and data interpretation. Using a neon-like yttrium x-ray laser which operates at a wavelength of 15.5 mn, we have performed a series of soft x-ray laser interferometry experiments, operated in the skewed Mach-Zehnder configuration, to characterize plasmas relevant to both weapons and inertial confinement fusion. The two-dimensional density profiles obtained from the interferograms allow us to validate and benchmark our numerical models used to study the physics in the high-energy density regime, relevant to both weapons and inertial confinement fusion

  14. Temporal intensity interferometry: photon bunching in three bright stars

    Guerin, W.; Dussaux, A.; Fouché, M.; Labeyrie, G.; Rivet, J.-P.; Vernet, D.; Vakili, F.; Kaiser, R.

    2017-12-01

    We report the first intensity correlation measured with starlight since the historical experiments of Hanbury Brown and Twiss. The photon bunching g(2)(τ, r = 0), obtained in the photon-counting regime, was measured for three bright stars: α Boo, α CMi and β Gem. The light was collected at the focal plane of a 1-m optical telescope, transported by a multi-mode optical fibre, split into two avalanche photodiodes and correlated digitally in real time. For total exposure times of a few hours, we obtained contrast values around 2 × 10-3, in agreement with the expectation for chaotic sources, given the optical and electronic bandwidths of our set-up. Comparing our results with the measurement of Hanbury Brown et al. for α CMi, we argue for the timely opportunity to extend our experiments to measuring the spatial correlation function over existing and/or foreseen arrays of optical telescopes diluted over several kilometres. This would enable microarcsec long-baseline interferometry in the optical, especially in the visible wavelengths, with a limiting magnitude of 10.

  15. Symmetric large momentum transfer for atom interferometry with BECs

    Abend, Sven; Gebbe, Martina; Gersemann, Matthias; Rasel, Ernst M.; Quantus Collaboration

    2017-04-01

    We develop and demonstrate a novel scheme for a symmetric large momentum transfer beam splitter for interferometry with Bose-Einstein condensates. Large momentum transfer beam splitters are a key technique to enhance the scaling factor and sensitivity of an atom interferometer and to create largely delocalized superposition states. To realize the beam splitter, double Bragg diffraction is used to create a superposition of two symmetric momentum states. Afterwards both momentum states are loaded into a retro-reflected optical lattice and accelerated by Bloch oscillations on opposite directions, keeping the initial symmetry. The favorable scaling behavior of this symmetric acceleration, allows to transfer more than 1000 ℏk of total differential splitting in a single acceleration sequence of 6 ms duration while we still maintain a fraction of approx. 25% of the initial atom number. As a proof of the coherence of this beam splitter, contrast in a closed Mach-Zehnder atom interferometer has been observed with up to 208 ℏk of momentum separation, which equals a differential wave-packet velocity of approx. 1.1 m/s for 87Rb. The presented work is supported by the CRC 1128 geo-Q and the DLR with funds provided by the Federal Ministry of Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under Grant No. DLR 50WM1552-1557 (QUANTUS-IV-Fallturm).

  16. Design of multichannel laser interferometry for W7-X

    Kornejew, P.; Hirsch, M.; Bindemann, T.; Dinklage, A.; Dreier, H.; Hartfuss, H.-J.

    2006-01-01

    An eight channel interferometer is developed for density feedback control and the continuous measurement of electron density profiles in the stellarator W7-X. An additional sightline is launched in the geometry of the Thomson scattering for cross calibration. Due to the W7-X coil geometry access is strongly restricted. This motivates the optimization of the sightline geometry and design studies for supplementary chords. In-vessel retroreflectors will be used and inserted in the first wall elements. To cope with associated mechanical vibrations and thermal drifts during the discharges with envisaged duration of 30 min either two-color or second harmonic interferometry techniques must be applied. Optimum wavelengths are found to be about 10 and 5 μm. A CO 2 /CO interferometer (10 μm/5 μm) will be tested and compared with an existing CO 2 /HeNe test interferometer. A special difficulty of remotely operated diagnostics is the need of long transmission lines with a path length of about 60 m required from the diagnostics location to the torus hall and back. Different arrangements will be compared

  17. On the resolving power of 2-D interferometry

    Padula, Sandra S. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil)

    1996-12-31

    A resonance gas model previously proposed is here briefly reviewed in order to illustrate some of the geometrical and dynamical effects that could distort the behavior of the two pion correlation function. The main of these effects - the resonance decaying into pions - has earlier been conceived as a possible means to probe resonance abundances at different energy ranges. However, reinforcing previous studies, we show here that the conventional 1-D projection of the correlation function does not allow for clear conclusions. Instead, we propose to use the 2-D projection associated to a 2-D {sub X}{sup 2} analysis, which substantially enhances the resolving power of interferometry to differentiate decoupling geometries of distinct dynamical models. This result is achieved by studying the variation of the mean {sub X}{sup 2} per degrees of freedom with respect to the range of the analysis in the ({sub qT}, {sub qL}) plane. The preliminary E802 data on Si + Au at 14.6 A GeV/c, used here for illustrating the method, seem to rule out dynamical models with high {omega}, {eta} resonance formation yields. (author) 24 refs., 5 figs.

  18. On the resolving power of 2-D interferometry

    Padula, Sandra S.

    1996-01-01

    A resonance gas model previously proposed is here briefly reviewed in order to illustrate some of the geometrical and dynamical effects that could distort the behavior of the two pion correlation function. The main of these effects - the resonance decaying into pions - has earlier been conceived as a possible means to probe resonance abundances at different energy ranges. However, reinforcing previous studies, we show here that the conventional 1-D projection of the correlation function does not allow for clear conclusions. Instead, we propose to use the 2-D projection associated to a 2-D X 2 analysis, which substantially enhances the resolving power of interferometry to differentiate decoupling geometries of distinct dynamical models. This result is achieved by studying the variation of the mean X 2 per degrees of freedom with respect to the range of the analysis in the ( qT , qL ) plane. The preliminary E802 data on Si + Au at 14.6 A GeV/c, used here for illustrating the method, seem to rule out dynamical models with high ω, η resonance formation yields. (author)

  19. Research on long-range grating interferometry with nanometer resolution

    Chu, Xingchun; Zhao, Shanghong; Lü, Haibao

    2008-01-01

    Grating interferometry that features long range and nanometer resolution is presented. The optical system was established based on a single long metrology grating. The large fringe multiplication was achieved by properly selecting two high-order diffraction beams to form a fringe pattern. The fringe pattern collected by a linear array was first tailored to a few multiples of fringes in order to suppress the effect of the energy leakage on phase-extracting precision when the fast Fourier transform (FFT) algorithm was used to calculate its phase. Thus, the phase-extracting precision of a tailored fringe pattern by FFT was greatly improved. Based on this, a novel subdividing method, which exploited the time-shift property of FFT, was developed to subdivide the fringe with large multiple and high accuracy. Numerical results show that the system resolution reaches 1 nm. The experimental results obtained against a capacitive sensor in the sub-mm range show that the measurement precision of the system is less than 10 nm. (technical design note)

  20. Mapping Arctic Bottomfast Sea Ice Using SAR Interferometry

    Dyre O. Dammann

    2018-05-01

    Full Text Available Bottomfast sea ice is an integral part of many near-coastal Arctic ecosystems with implications for subsea permafrost, coastal stability and morphology. Bottomfast sea ice is also of great relevance to over-ice travel by coastal communities, industrial ice roads, and marine habitats. There are currently large uncertainties around where and how much bottomfast ice is present in the Arctic due to the lack of effective approaches for detecting bottomfast sea ice on large spatial scales. Here, we suggest a robust method capable of detecting bottomfast sea ice using spaceborne synthetic aperture radar interferometry. This approach is used to discriminate between slowly deforming floating ice and completely stationary bottomfast ice based on the interferometric phase. We validate the approach over freshwater ice in the Mackenzie Delta, Canada, and over sea ice in the Colville Delta and Elson Lagoon, Alaska. For these areas, bottomfast ice, as interpreted from the interferometric phase, shows high correlation with local bathymetry and in-situ ice auger and ground penetrating radar measurements. The technique is further used to track the seasonal evolution of bottomfast ice in the Kasegaluk Lagoon, Alaska, by identifying freeze-up progression and areas of liquid water throughout winter.

  1. Distortion of two-pion interferometry by multipion correlations

    Zhang, W.N.; Liu, Y.M.; Wang, S.; Liu, Q.J.; Jiang, J.; Keane, D.; Shao, Y.; Chu, S.Y.; Fung, S.Y.

    1993-01-01

    Multipion correlations arising from the symmetrization of the n-pion wave function affect the extracted information from two-pion correlation measurements. The influence of multipion correlations on a sample of like-pion pairs can be expressed as a multipion correlation factor, the distribution of which offers good sensitivity to the multipion correlation effect. Analyses of the multipion correlation factor for two Bevalac streamer chamber data samples of 2.1A GeV Ne+Pb and 1.8A GeV Ar+Pb collisions show that the multipion correlation effect in the former sample is greater than in the latter. This result mainly arises from the fact that the pion source for Ne projectiles is smaller than for Ar projectiles. The residual correlations in the reference sample are related to the multipion correlation factor in multipion events, which can be expressed as a residual correlation factor. The influence of multipion correlations on two-pion interferometry analyses arises from the ratio of the residual correlation factor to the multipion correlation factor

  2. Distributed gas sensing with optical fibre photothermal interferometry.

    Lin, Yuechuan; Liu, Fei; He, Xiangge; Jin, Wei; Zhang, Min; Yang, Fan; Ho, Hoi Lut; Tan, Yanzhen; Gu, Lijuan

    2017-12-11

    We report the first distributed optical fibre trace-gas detection system based on photothermal interferometry (PTI) in a hollow-core photonic bandgap fibre (HC-PBF). Absorption of a modulated pump propagating in the gas-filled HC-PBF generates distributed phase modulation along the fibre, which is detected by a dual-pulse heterodyne phase-sensitive optical time-domain reflectometry (OTDR) system. Quasi-distributed sensing experiment with two 28-meter-long HC-PBF sensing sections connected by single-mode transmission fibres demonstrated a limit of detection (LOD) of ∼10 ppb acetylene with a pump power level of 55 mW and an effective noise bandwidth (ENBW) of 0.01 Hz, corresponding to a normalized detection limit of 5.5ppb⋅W/Hz. Distributed sensing experiment over a 200-meter-long sensing cable made of serially connected HC-PBFs demonstrated a LOD of ∼ 5 ppm with 62.5 mW peak pump power and 11.8 Hz ENBW, or a normalized detection limit of 312ppb⋅W/Hz. The spatial resolution of the current distributed detection system is limited to ∼ 30 m, but it is possible to reduce down to 1 meter or smaller by optimizing the phase detection system.

  3. Disentangling stellar activity from exoplanetary signals with interferometry

    Ligi Roxanne

    2015-01-01

    Full Text Available Stellar activity can express as many forms at stellar surfaces: dark spots, convective cells, bright plages. Particularly, dark spots and bright plages add noise on photometric data or radial velocity measurements used to detect exoplanets, and thus lead to false detection or disrupt their derived parameters. Since interferometry provides a very high angular resolution, it may constitute an interesting solution to distinguish the signal of a transiting exoplanet and that of stellar activity. It has also been shown that granulation adds bias in visibility and closure phase measurements, affecting in turn the derived stellar parameters. We analyze the noises generated by dark spots on interferometric observables and compare them to exoplanet signals. We investigate the current interferometric instruments able to measure and disentangle these signals, and show that there is a lack in spatial resolution. We thus give a prospective of the improvements to be brought on future interferometers, which would also significantly extend the number of available targets.

  4. Gravity sensing using Very Long Baseline Atom Interferometry

    Schlippert, D.; Wodey, E.; Meiners, C.; Tell, D.; Schubert, C.; Ertmer, W.; Rasel, E. M.

    2017-12-01

    Very Long Baseline Atom Interferometry (VLBAI) has applications in high-accuracy absolute gravimetry, gravity-gradiometry, and for tests of fundamental physics. Thanks to the quadratic scaling of the phase shift with increasing free evolution time, extending the baseline of atomic gravimeters from tens of centimeters to meters puts resolutions of 10-13g and beyond in reach.We present the design and progress of key elements of the VLBAI-test stand: a dual-species source of Rb and Yb, a high-performance two-layer magnetic shield, and an active vibration isolation system allowing for unprecedented stability of the mirror acting as an inertial reference. We envisage a vibration-limited short-term sensitivity to gravitational acceleration of 1x10-8 m/s-2Hz-1/2 and up to a factor of 25 improvement when including additional correlation with a broadband seismometer. Here, the supreme long-term stability of atomic gravity sensors opens the route towards competition with superconducting gravimeters. The operation of VLBAI as a differential dual-species gravimeter using ultracold mixtures of Yb and Rb atoms enables quantum tests of the universality of free fall (UFF) at an unprecedented level of <10-13, potentially surpassing the best experiments to date.

  5. Wave-particle dualism in matter wave interferometry

    Rauch, H.

    1984-01-01

    Neutron interferometry is a unique tool for investigations in the field of particle-wave dualism because massive elementary particles behave like waves within the interferometer. The invention of perfect crystal neutron interferometers providing widely separated coherent beams stimulated a great variety of experiments with matter waves in the field of basic quantum mechanics. The phase of the spatial and spinor wave function become a measurable quantity and can be influenced individually. High degrees of coherence and high order interferences have been observed by this technique. The 4π-symmetry of a spinor wave function and the mutual modulation of nuclear and magnetic phase shifts have been measured in the past. Recent experiments dealt with polarized neutron beams, which are handled to realize the spin-superposition of two oppositionally polarized subbeams resulting in final polarization perpendicular to both initial beam polarizations. The different action on the coherent beams of static and dynamic flippers have been visualized. Monolithic multicrystal arrangements in Laue position can also be used to achieve an extremely high energy (10 -9 eV) or angular resolution (0.001 sec of arc). This feature is based on the Pendelloesung interference within the perfect crystal. A transverse coherence length up to 6.5 mm is deduced from single slit diffraction experiments. (Auth.)

  6. Sensitivity analysis of periodic errors in heterodyne interferometry

    Ganguly, Vasishta; Kim, Nam Ho; Kim, Hyo Soo; Schmitz, Tony

    2011-01-01

    Periodic errors in heterodyne displacement measuring interferometry occur due to frequency mixing in the interferometer. These nonlinearities are typically characterized as first- and second-order periodic errors which cause a cyclical (non-cumulative) variation in the reported displacement about the true value. This study implements an existing analytical periodic error model in order to identify sensitivities of the first- and second-order periodic errors to the input parameters, including rotational misalignments of the polarizing beam splitter and mixing polarizer, non-orthogonality of the two laser frequencies, ellipticity in the polarizations of the two laser beams, and different transmission coefficients in the polarizing beam splitter. A local sensitivity analysis is first conducted to examine the sensitivities of the periodic errors with respect to each input parameter about the nominal input values. Next, a variance-based approach is used to study the global sensitivities of the periodic errors by calculating the Sobol' sensitivity indices using Monte Carlo simulation. The effect of variation in the input uncertainty on the computed sensitivity indices is examined. It is seen that the first-order periodic error is highly sensitive to non-orthogonality of the two linearly polarized laser frequencies, while the second-order error is most sensitive to the rotational misalignment between the laser beams and the polarizing beam splitter. A particle swarm optimization technique is finally used to predict the possible setup imperfections based on experimentally generated values for periodic errors

  7. Sensitivity analysis of periodic errors in heterodyne interferometry

    Ganguly, Vasishta; Kim, Nam Ho; Kim, Hyo Soo; Schmitz, Tony

    2011-03-01

    Periodic errors in heterodyne displacement measuring interferometry occur due to frequency mixing in the interferometer. These nonlinearities are typically characterized as first- and second-order periodic errors which cause a cyclical (non-cumulative) variation in the reported displacement about the true value. This study implements an existing analytical periodic error model in order to identify sensitivities of the first- and second-order periodic errors to the input parameters, including rotational misalignments of the polarizing beam splitter and mixing polarizer, non-orthogonality of the two laser frequencies, ellipticity in the polarizations of the two laser beams, and different transmission coefficients in the polarizing beam splitter. A local sensitivity analysis is first conducted to examine the sensitivities of the periodic errors with respect to each input parameter about the nominal input values. Next, a variance-based approach is used to study the global sensitivities of the periodic errors by calculating the Sobol' sensitivity indices using Monte Carlo simulation. The effect of variation in the input uncertainty on the computed sensitivity indices is examined. It is seen that the first-order periodic error is highly sensitive to non-orthogonality of the two linearly polarized laser frequencies, while the second-order error is most sensitive to the rotational misalignment between the laser beams and the polarizing beam splitter. A particle swarm optimization technique is finally used to predict the possible setup imperfections based on experimentally generated values for periodic errors.

  8. Spaceborne Polarimetric SAR Interferometry: Performance Analysis and Mission Concepts

    Shane R. Cloude

    2005-12-01

    Full Text Available We investigate multichannel imaging radar systems employing coherent combinations of polarimetry and interferometry (Pol-InSAR. Such systems are well suited for the extraction of bio- and geophysical parameters by evaluating the combined scattering from surfaces and volumes. This combination leads to several important differences between the design of Pol-InSAR sensors and conventional single polarisation SAR interferometers. We first highlight these differences and then investigate the Pol-InSAR performance of two proposed spaceborne SAR systems (ALOS/PalSAR and TerraSAR-L operating in repeat-pass mode. For this, we introduce the novel concept of a phase tube which enables (1 a quantitative assessment of the Pol-InSAR performance, (2 a comparison between different sensor configurations, and (3 an optimization of the instrument settings for different Pol-InSAR applications. The phase tube may hence serve as an interface between system engineers and application-oriented scientists. The performance analysis reveals major limitations for even moderate levels of temporal decorrelation. Such deteriorations may be avoided in single-pass sensor configurations and we demonstrate the potential benefits from the use of future bi- and multistatic SAR interferometers.

  9. All-Sky Interferometry with Spherical Harmonic Transit Telescopes

    Shaw, J.Richard [Canadian Inst. Theor. Astrophys.; Sigurdson, Kris [British Columbia U.; Pen, Ue-Li [Canadian Inst. Theor. Astrophys.; Stebbins, Albert [Fermilab; Sitwell, Michael [British Columbia U.

    2013-02-01

    In this paper we describe the spherical harmonic transit telescope, a novel formalism for the analysis of transit radio telescopes. This all-sky approach bypasses the curved sky complications of traditional interferometry and so is particularly well suited to the analysis of wide-field radio interferometers. It enables compact and computationally efficient representations of the data and its statistics that allow new ways of approaching important problems like map-making and foreground removal. In particular, we show how it enables the use of the Karhunen-Loeve transform as a highly effective foreground filter, suppressing realistic foreground residuals for our fiducial example by at least a factor twenty below the 21cm signal even in highly contaminated regions of the sky. This is despite the presence of the angle-frequency mode mixing inherent in real-world instruments with frequency-dependent beams. We show, using Fisher forecasting, that foreground cleaning has little effect on power spectrum constraints compared to hypothetical foreground-free measurements. Beyond providing a natural real-world data analysis framework for 21cm telescopes now under construction and future experiments, this formalism allows accurate power spectrum forecasts to be made that include the interplay of design constraints and realistic experimental systematics with twenty-first century 21cm science.

  10. Nozzle for electric dispersion reactor

    Sisson, W.G.; Basaran, O.A.; Harris, M.T.

    1995-11-07

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

  11. Impacto da tecnologia de informação no Supply Chain Management: um estudo multicaso sobre a adoção de EDI entre varejo e indústria agroalimentar The impact of information technology on the Supply Chain Management: a multicase study in EDI adoption between the agrifood industry and retailers

    Andrea Lago da Silva

    1999-12-01

    Full Text Available As tecnologias de informação têm alterado as formas de coordenação entre os diferentes elos da cadeia de suprimentos. A coordenação pode ser entendida como a habilidade de transmitir informação, estímulos e controles ao longo das etapas seqüenciais que integram o conjunto de atividades necessárias para atender o mercado (FARINA & ZYLBERSZTAJN, 1994. O conjunto destas etapas é o que tem sido chamado de Supply Chain ou Cadeia de Suprimentos. Neste artigo, discute-se alguns casos de adoção de uma tecnologia de informação, o EDI (troca eletrônica de dados como ferramenta de coordenação entre varejistas e indústrias agroalimentares. Conclui-se que o processo de adoção é relativamente recente para que se possa mensurar resultados quantitativos e qualitativos significativos, mas já se observa alterações na freqüência de desabastecimento, em estoques melhor dimensionados e vendas maiores em decorrência da maior disponibilidade de mercadorias. Sinalizam-se também mudanças qualitativas, como alteração na função do vendedor tradicional, maior interação entre as áreas técnicas, com um aprendizado comum das novas formas de usar a tecnologia e o importante papel da confiança nos relacionamentos interorganizações.Information technology has changed the patterns of coordination among the different linkages of supply-chains. Coordination can be understood as the ability to transfer information, incentives and controls throughout the sequential stages which integrate the set of activities indispensable to serve the market (FARINA & ZYLBERSZTAJN, 1994. The sum of these stages is currently known as Supply-Chains. This paper discusses cases of adopting a specific information technology, EDI (Electronic Data Interchange, as an integration tool between the food industry and retailers. It was found that the adoption process is too recent to measure significative quantitative results, but it is possible to observe changes in the

  12. Application of deconvolution interferometry with both Hi-net and KiK-net data

    Nakata, N.

    2013-12-01

    Application of deconvolution interferometry to wavefields observed by KiK-net, a strong-motion recording network in Japan, is useful for estimating wave velocities and S-wave splitting in the near surface. Using this technique, for example, Nakata and Snieder (2011, 2012) found changed in velocities caused by Tohoku-Oki earthquake in Japan. At the location of the borehole accelerometer of each KiK-net station, a velocity sensor is also installed as a part of a high-sensitivity seismograph network (Hi-net). I present a technique that uses both Hi-net and KiK-net records for computing deconvolution interferometry. The deconvolved waveform obtained from the combination of Hi-net and KiK-net data is similar to the waveform computed from KiK-net data only, which indicates that one can use Hi-net wavefields for deconvolution interferometry. Because Hi-net records have a high signal-to-noise ratio (S/N) and high dynamic resolution, the S/N and the quality of amplitude and phase of deconvolved waveforms can be improved with Hi-net data. These advantages are especially important for short-time moving-window seismic interferometry and deconvolution interferometry using later coda waves.

  13. HIGH-PRECISION ASTROMETRIC MILLIMETER VERY LONG BASELINE INTERFEROMETRY USING A NEW METHOD FOR MULTI-FREQUENCY CALIBRATION

    Dodson, Richard; Rioja, María J. [International Centre for Radio Astronomy Research, M468, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009 (Australia); Molina, Sol N.; Gómez, José L., E-mail: richard.dodson@icrar.org [Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, E-18008 Granada (Spain)

    2017-01-10

    In this paper we describe a new approach for millimeter Very Long Baseline Interferometry (mm-VLBI) calibration that provides bona-fide astrometric alignment of the millimeter-wavelength images from a single source, for the measurement of frequency-dependent effects, such as “core-shifts” near the black hole of active galactic nucleus jets. We achieve our astrometric alignment by solving first for the ionospheric (dispersive) contributions using wide-band centimeter-wavelength observations. Second, we solve for the tropospheric (non-dispersive) contributions by using fast frequency-switching at the target millimeter-wavelengths. These solutions can be scaled and transferred from low frequency to the high frequency. To complete the calibration chain an additional step is required to remove a residual constant phase offset on each antenna. The result is an astrometric calibration and the measurement of the core-shift between 22 and 43 GHz for the jet in BL Lacertae to be −8 ± 5, 20 ± 6 μ as, in R.A. and decl., respectively. By comparison to conventional phase referencing at centimeter-wavelengths we are able to show that this core shift at millimeter-wavelengths is significantly less than what would be predicted by extrapolating the low-frequency result, which closely followed the predictions of the Blandford and Königl conical jet model. As such it would be the first demonstration for the association of the VLBI core with a recollimation shock, normally hidden at low frequencies due to the optical depth, which could be responsible for the γ -ray production in blazar jets.

  14. HIGH-PRECISION ASTROMETRIC MILLIMETER VERY LONG BASELINE INTERFEROMETRY USING A NEW METHOD FOR MULTI-FREQUENCY CALIBRATION

    Dodson, Richard; Rioja, María J.; Molina, Sol N.; Gómez, José L.

    2017-01-01

    In this paper we describe a new approach for millimeter Very Long Baseline Interferometry (mm-VLBI) calibration that provides bona-fide astrometric alignment of the millimeter-wavelength images from a single source, for the measurement of frequency-dependent effects, such as “core-shifts” near the black hole of active galactic nucleus jets. We achieve our astrometric alignment by solving first for the ionospheric (dispersive) contributions using wide-band centimeter-wavelength observations. Second, we solve for the tropospheric (non-dispersive) contributions by using fast frequency-switching at the target millimeter-wavelengths. These solutions can be scaled and transferred from low frequency to the high frequency. To complete the calibration chain an additional step is required to remove a residual constant phase offset on each antenna. The result is an astrometric calibration and the measurement of the core-shift between 22 and 43 GHz for the jet in BL Lacertae to be −8 ± 5, 20 ± 6 μ as, in R.A. and decl., respectively. By comparison to conventional phase referencing at centimeter-wavelengths we are able to show that this core shift at millimeter-wavelengths is significantly less than what would be predicted by extrapolating the low-frequency result, which closely followed the predictions of the Blandford and Königl conical jet model. As such it would be the first demonstration for the association of the VLBI core with a recollimation shock, normally hidden at low frequencies due to the optical depth, which could be responsible for the γ -ray production in blazar jets.

  15. Tracer dispersion - experiment and CFD

    Zitny, R.

    2004-01-01

    Description of tracer distribution by means of dispersion models is a method successfully used in process engineering for fifty years. Application of dispersion models in reactor engineering for characterization of flows in column apparatus, heat exchangers, etc. is summarized and experimental tracer techniques as well as CFD methods for dispersion coefficients evaluation are discussed. Possible extensions of thermal axial dispersion model (ADM) and a core-wall ADM model suitable for description of tracer dispersion in laminar flows are suggested as well as CFD implementation as 1D finite elements. (author)

  16. High density dispersion fuel

    Hofman, G.L.

    1996-01-01

    A fuel development campaign that results in an aluminum plate-type fuel of unlimited LEU burnup capability with an uranium loading of 9 grams per cm 3 of meat should be considered an unqualified success. The current worldwide approved and accepted highest loading is 4.8 g cm -3 with U 3 Si 2 as fuel. High-density uranium compounds offer no real density advantage over U 3 Si 2 and have less desirable fabrication and performance characteristics as well. Of the higher-density compounds, U 3 Si has approximately a 30% higher uranium density but the density of the U 6 X compounds would yield the factor 1.5 needed to achieve 9 g cm -3 uranium loading. Unfortunately, irradiation tests proved these peritectic compounds have poor swelling behavior. It is for this reason that the authors are turning to uranium alloys. The reason pure uranium was not seriously considered as a dispersion fuel is mainly due to its high rate of growth and swelling at low temperatures. This problem was solved at least for relatively low burnup application in non-dispersion fuel elements with small additions of Si, Fe, and Al. This so called adjusted uranium has nearly the same density as pure α-uranium and it seems prudent to reconsider this alloy as a dispersant. Further modifications of uranium metal to achieve higher burnup swelling stability involve stabilization of the cubic γ phase at low temperatures where normally α phase exists. Several low neutron capture cross section elements such as Zr, Nb, Ti and Mo accomplish this in various degrees. The challenge is to produce a suitable form of fuel powder and develop a plate fabrication procedure, as well as obtain high burnup capability through irradiation testing

  17. «Dos benefícios de Deus»: três edições de um capítulo do tratado medieval português

    Rita de Cássia Ribeiro Queiroz

    2010-12-01

    Full Text Available Resumo: O tratado “Dos benefícios de Deus” integra a obra da literatura medieval portuguesa intitulada Castelo perigoso, a qual é uma adaptação do texto francês escrito por Frère Robert, monge cartuxo, à sua prima Soeur Rose, da Ordem Fontevrault. A versão em língua portuguesa foi realizada no Mosteiro de Alcobaça, provavelmente no século XV, existindo dois códices (ALC 197 e ALC 214, os quais se encontram na Biblioteca Nacional de Portugal. O tratado “Dos benefícios de Deus” é o segundo na ordem dos textos que compõem a obra Castelo perigoso. Propõem-se, neste trabalho, três edições de um capítulo do tratado“Dos benefícios de Deus”, a saber: uma edição conservadora ou semidiplomática; uma edição crítica, executada a partir da collatio entre os códices ALC 197 e ALC 214 e a edição realizada por Augusto Magne na década de 1940; e, por último, uma edição modernizada. Palavras-chave: Crítica textual; edição; português medieval.  Résumé: Le traité “Dos benefícios de Deus” intègre l’oeuvre de la littérature médiévale potugaise Chastel périlleux, qui est une adaptation du texte français écrit par Robert Frère, moine chartreux, à sa cousine Soeur Rose, de l’Ordre Fontevrault. La version en langue portugaise a été réalisée au Monastère d’Alcobaça, probablement au XVe siècle: il y a deux codex (ALC 197 et ALC 214, qui sont à la Bibliothèque Nationale du Portugal. Le traité “Dos benefícios de Deus” est le deuxième dans l’ordre des textes qui constituent l’oeuvre Chastel périlleux. Sont proposées dans le présent travail trois éditions d’un chapitre du traité “Dos benefícios de Deus”, à savoir: une édition conservatrice ou semidiplomatique; une édition critique, faite à partir de la collation des manuscrits entre les codex 197 et 214 et l’édition faite par Augusto Magne en 1940; et, enfin, une édition modernisée. Mots-clés: Critique textuelle

  18. Spurious dispersion effects at FLASH

    Prat, Eduard

    2009-07-01

    The performance of the Free-Electron Laser (FEL) process imposes stringent demands on the transverse trajectory and size of the electron beam. Since transverse dispersion changes off-energy particle trajectories and increases the effective beam size, dispersion must be controlled. This thesis treats the concept of dispersion in linacs, and analyses the impact of dispersion on the electron beam and on the FEL process. It presents generation mechanisms for spurious dispersion, quantifying its importance for FLASH (Free-electron Laser in Hamburg) and the XFEL (European X-ray Free-Electron Laser). A method for measuring and correcting dispersion and its implementation in FLASH is described. Experiments of dispersion e ects on the transverse beam quality and on the FEL performance are presented. (orig.)

  19. Spurious dispersion effects at FLASH

    Prat, Eduard

    2009-07-15

    The performance of the Free-Electron Laser (FEL) process imposes stringent demands on the transverse trajectory and size of the electron beam. Since transverse dispersion changes off-energy particle trajectories and increases the effective beam size, dispersion must be controlled. This thesis treats the concept of dispersion in linacs, and analyses the impact of dispersion on the electron beam and on the FEL process. It presents generation mechanisms for spurious dispersion, quantifying its importance for FLASH (Free-electron Laser in Hamburg) and the XFEL (European X-ray Free-Electron Laser). A method for measuring and correcting dispersion and its implementation in FLASH is described. Experiments of dispersion e ects on the transverse beam quality and on the FEL performance are presented. (orig.)

  20. Dispersion stability of thermal nanofluids

    Fan Yu

    2017-10-01

    Full Text Available Thermal nanofluids, the engineered fluids with dispersed functional nanoparticles, have exhibited extraordinary thermophysical properties and added functionalities, and thus have enabled a broad range of important applications. The poor dispersion stability of thermal nanofluids, however, has been considered as a long-existing issue that limits their further development and practical application. This review overviews the recent efforts and progresses in improving the dispersion stability of thermal nanofluids such as mechanistic understanding of dispersion behavior of nanofluids, examples of both water-based and oil-based nanofluids, strategies to stabilize nanofluids, and characterization techniques for dispersion behavior of nanofluids. Finally, on-going research needs, and possible solutions to research challenges and future research directions in exploring stably dispersed thermal nanofluids are discussed. Keywords: Thermal nanofluids, Dispersion, Aggregation, Electrostatic stabilization, Steric stabilization

  1. Měření indexu lomu vzduchu pomocí interferometrie nízké koherence

    Pikálek, Tomáš; Buchta, Zdeněk

    2017-01-01

    Roč. 62, č. 10 (2017), s. 253-256 ISSN 0447-6441 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : air refractive index * laser interferometry * low-coherence interferometry Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics)

  2. Phonon dispersion in vanadium

    Ivanov, A.S.; Rumiantsev, A.Yu.

    1999-01-01

    Complete text of publication follows. Phonon dispersion curves in Vanadium metal are investigated by neutron inelastic scattering using three-axis spectrometers. Due to extremely low coherent scattering amplitude of neutrons in natural isotope mixture of vanadium the phonon frequencies could be determined in the energy range below about 15 meV. Several phonon groups were measured with the polarised neutron scattering set-up. It is demonstrated that the intensity of coherent inelastic scattering observed in the non-spin-flip channel vanishes in the spin-flip channel. The phonon density of states is measured on a single crystal keeping the momentum transfer equal to a vector of reciprocal lattice where the coherent inelastic scattering is suppressed. Phonon dispersion curves in vanadium, as measured by neutron and earlier by X-ray scattering, are described in frames of a charge-fluctuation model involving monopolar and dipolar degrees of freedom. The model parameters are compared for different transition metals with body-centred cubic-structure. (author)

  3. Dispersion and current measurements

    Boelskifte, S.

    1986-04-01

    A model for the simulation of particle movements in water should incorporate the mutual distance dependent correlation. As long as reliable data are given accessible a model can be created of the dispersion in a given area from a statistical description of turbulence. Current measurements have been performed in an area north of the Swedish nuclear power plant Barsebaeck, and statistical time series analysis have made it possible to estimate multivariate autoregressive moving-average (ARMA) models for these data using the Box-Jenkins method. The correlation structure for the area has been investigated in detail. Transport and dispersion models for the marine environment are used in estimating doses to the population from the aquatic food chain. Some of these models are described with special emphasis on the time and length scales they cover. Furthermore, to illustrate the background of the simulation model, short introductuions are given to health physics, time series analysis, and turbulence theory. Analysis of the simulation model shows the relative importance of the different parameters. The model can be expanded to conditional simulation, where the current measurements are used directly to simulate the movement of one of the particles. Results from the model are also compared to results from a sampling of bioindicators (Fucus vesiculosus) along the Danish coast. The reliability of bioindicators in this kind of experiment is discussed. (author)

  4. Quantum optical rotatory dispersion

    Tischler, Nora; Krenn, Mario; Fickler, Robert; Vidal, Xavier; Zeilinger, Anton; Molina-Terriza, Gabriel

    2016-01-01

    The phenomenon of molecular optical activity manifests itself as the rotation of the plane of linear polarization when light passes through chiral media. Measurements of optical activity and its wavelength dependence, that is, optical rotatory dispersion, can reveal information about intricate properties of molecules, such as the three-dimensional arrangement of atoms comprising a molecule. Given a limited probe power, quantum metrology offers the possibility of outperforming classical measurements. This has particular appeal when samples may be damaged by high power, which is a potential concern for chiroptical studies. We present the first experiment in which multiwavelength polarization-entangled photon pairs are used to measure the optical activity and optical rotatory dispersion exhibited by a solution of chiral molecules. Our work paves the way for quantum-enhanced measurements of chirality, with potential applications in chemistry, biology, materials science, and the pharmaceutical industry. The scheme that we use for probing wavelength dependence not only allows one to surpass the information extracted per photon in a classical measurement but also can be used for more general differential measurements. PMID:27713928

  5. O Brasil através dos Para-brisas: O Turismo na Primeira Edição da Revista Quatro Rodas

    Maria Henriqueta S. Garcia Gimenes-Minasse

    2014-07-01

    Full Text Available É grande a importância dos guias turísticos na construção da imagem de destinos turísticos, pois auxiliam a organização de viagens, selecionando o que merece ser visto e visitado. No Brasil, um dos mais respeitados pelos turistas domésticos é o Guia Quatro Rodas, publicado anualmente pela Editora Abril, desde setembro de 1965. Contudo, já em 1960 a revista Quatro Rodas, criada nesse ano, e da qual o Guia nasceu, já vinha desempenhando o papel de informar e orientar o leitor sobre passeios e roteiros que poderiam ser feitos de automóvel. Este artigo tem o objetivo de analisar o conteúdo relacionado ao Turismo da primeira edição da Revista Quatro Rodas. Os principais resultados encontrados evidenciam a transformação social do Brasil com o advento de uma matriz econômica pautada na indústria do automóvel e com a incorporação das viagens de lazer como uma forma de descoberta desse ‘novo’ país.  Brazil through the Windshield: Tourism in the First Edition of Quatro Rodas Magazine - Tour guides are very important in building the image of touristic attractions, as they help with travel arrangements and selection of attractions to be seen and visited. In Brazil Guia Quatro Rodas is one of the guides most respected by domestic tourists. It is annually published by Editora Abril, since September 1965. Nevertheless, since 1960 the newly formed Quatro Rodas magazine, and from which the Guia Quatro Rodas was borne, was already playing the role of informing and guiding its readers in relation to tours that could be made by car. The scope of this article is to analyze the first edition of Quatro Rodas magazine with respect to its tourism-related content. The main results show the social transformation of Brazil with the advent of an economic matrix based on the automotive industry and the incorporation of leisure travel as a way to discover the ‘new’ country.

  6. Esta tenzon fezeron Pero da Ponte e Afonso Anes do Coton. Edição e estudo do debate B969/V556

    Déborah González Martínez

    2013-07-01

    Full Text Available Pero da Ponte e Afonso Eanes do Coton são dois destacados autores de cantigas transmitidas nos cancioneiros galego-portugueses: o Cancioneiro da Ajuda, o Cancioneiro da Biblioteca Nacional (Cód. 10991 e o Cancioneiro da Biblioteca Vaticana (Vat. Lat. 4803. A estreita relação entre estes dois trovadores confirma-se pelas menções a ambos no interior de vários textos de natureza satírica e pela interação em duas cantigas dialogadas. O presente trabalho consiste numa nova edição crítica da tenção entre Afonso Eanes do Coton e Pero da Ponte (Pero da Pont’, e[n] un vosso cantar, B969 / V556, oferecendo novas respostas a velhas dificuldades ecdóticas. O texto vai acompanhado de anotação e estudo, pois o diálogo desenvolve vários temas de especial interesse para os estudos trovadorescos: a classe social e a atividade profissional dos interlocutores.Pero da Ponte and Afonso Eanes do Coton are two renowned authors of cantigas contained in the galician-portuguese songbooks: the Cancioneiro da Ajuda, the Cancioneiro da Biblioteca Nacional (Cód. 10991 and the Cancioneiro da Biblioteca Vaticana (Vat. Lat. 4803. The close relationship between these troubadours is confirmed by some references in satirical texts and, mainly, by the dialogued song Pero da Pont’, e[n] un vosso cantar (B969 / V556. This work offers a new critical edition of this tenção with notes and literary study. The dialogue develops several topics of interest for the studies about troubadours: social class and professional activity of the interlocutors.  

  7. Employee-Driven Innovation (EDI)

    Kesting, Peter; Ulhøi, John Parm

      The responsibility to be innovative and think of useful ideas and the privilege of making decisions in processes of innovation are typically restricted to specifically assigned R&D functions and/or upper echelon managers. Given the importance of innovation to most organizations, it may seem...

  8. Phase shifting white light interferometry using colour CCD for optical metrology and bio-imaging applications

    Upputuri, Paul Kumar; Pramanik, Manojit

    2018-02-01

    Phase shifting white light interferometry (PSWLI) has been widely used for optical metrology applications because of their precision, reliability, and versatility. White light interferometry using monochrome CCD makes the measurement process slow for metrology applications. WLI integrated with Red-Green-Blue (RGB) CCD camera is finding imaging applications in the fields optical metrology and bio-imaging. Wavelength dependent refractive index profiles of biological samples were computed from colour white light interferograms. In recent years, whole-filed refractive index profiles of red blood cells (RBCs), onion skin, fish cornea, etc. were measured from RGB interferograms. In this paper, we discuss the bio-imaging applications of colour CCD based white light interferometry. The approach makes the measurement faster, easier, cost-effective, and even dynamic by using single fringe analysis methods, for industrial applications.

  9. A portable magneto-optical trap with prospects for atom interferometry in civil engineering

    Hinton, A.; Perea-Ortiz, M.; Winch, J.; Briggs, J.; Freer, S.; Moustoukas, D.; Powell-Gill, S.; Squire, C.; Lamb, A.; Rammeloo, C.; Stray, B.; Voulazeris, G.; Zhu, L.; Kaushik, A.; Lien, Y.-H.; Niggebaum, A.; Rodgers, A.; Stabrawa, A.; Boddice, D.; Plant, S. R.; Tuckwell, G. W.; Bongs, K.; Metje, N.; Holynski, M.

    2017-06-01

    The high precision and scalable technology offered by atom interferometry has the opportunity to profoundly affect gravity surveys, enabling the detection of features of either smaller size or greater depth. While such systems are already starting to enter into the commercial market, significant reductions are required in order to reach the size, weight and power of conventional devices. In this article, the potential for atom interferometry based gravimetry is assessed, suggesting that the key opportunity resides within the development of gravity gradiometry sensors to enable drastic improvements in measurement time. To push forward in realizing more compact systems, techniques have been pursued to realize a highly portable magneto-optical trap system, which represents the core package of an atom interferometry system. This can create clouds of 107 atoms within a system package of 20 l and 10 kg, consuming 80 W of power. This article is part of the themed issue 'Quantum technology for the 21st century'.

  10. Testing the resolving power of 2-D K+ K+ interferometry at Ags energies

    Roldao, Cristiane G.; Padula, Sandra S.

    1998-01-01

    Adopting a procedure previously proposed to quantitatively study pion interferometry, an equivalent 2-D X 2 analysis was performed to test the resolving power of that method when applied to less favorable conditions, i.e., when non significant contribution from long lived resonances is expected, as in kaon interferometry. For that purpose, use is made of the preliminary E859 K + K + interferometry data from Si+Au collisions at 14.6 A GeV/c. Less sensitivity is achieved in the present case, although it is shown that it is still possible to distinguish two distinct decoupling geometries. The possible compatibility of the data with zero decoupling proper time interval, suggested by the experimental fit, is also investigated and seems to be ruled out when considering dynamical models with expanding sources. (author)

  11. Developing Wide-Field Spatio-Spectral Interferometry for Far-Infrared Space Applications

    Leisawitz, David; Bolcar, Matthew R.; Lyon, Richard G.; Maher, Stephen F.; Memarsadeghi, Nargess; Rinehart, Stephen A.; Sinukoff, Evan J.

    2012-01-01

    Interferometry is an affordable way to bring the benefits of high resolution to space far-IR astrophysics. We summarize an ongoing effort to develop and learn the practical limitations of an interferometric technique that will enable the acquisition of high-resolution far-IR integral field spectroscopic data with a single instrument in a future space-based interferometer. This technique was central to the Space Infrared Interferometric Telescope (SPIRIT) and Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) space mission design concepts, and it will first be used on the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). Our experimental approach combines data from a laboratory optical interferometer (the Wide-field Imaging Interferometry Testbed, WIIT), computational optical system modeling, and spatio-spectral synthesis algorithm development. We summarize recent experimental results and future plans.

  12. The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

    Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

    2015-10-01

    Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

  13. Interferometry with particles of non-zero rest mass: topological experiments

    Opat, G.I.

    1994-01-01

    Interferometry as a space-time process is described, together with its topology. Starting from this viewpoint, a convenient unified formalism for the phase shifts which arise in particle interferometry is developed. This formalism is based on a covariant form of Hamilton's action principle and Lagrange's equations of motion. It will be shown that this Lorentz invariant formalism yields a simple perturbation theoretic expression for the general phase shift that arises in matter-wave interferometry. The Lagrangian formalism is compared with the more usual formalism based on the wave propagation vector and frequency. The resulting formalism will be used to analyse the Sagnac effect, gravitational field measurements, and several Aharonov-Bohm-like topological phase shifts. Several topological interferometric experiments using particles of non-zero rest mass are discussed. These experiments involve the use of electrons, neutrons and neutral atoms. Neutron experiments will be emphasised. 45 refs., 15 figs

  14. Theoretical investigations on dual-beam illumination electronic speckle pattern interferometry

    Goudemand, Nicolas

    2006-01-01

    Contrary to what is found in most of the existing scientific literature,where a specific frame is developed, the theory of speckle interferometry is (conveniently) presented here as a particular case of the more general theory of holographic interferometry. In addition to the intellectual benefit of dealing with a single unified theory, this brings about many advantages when it comes to discuss fundamental topics such as the three-dimensional evolution of the complex amplitude of the diffuse optical wave fronts, the degree of approximation of the leading formulas, the loss of fringe contrast,the decorrelation effects, the real influence of the terms generally neglected in out-of-focus regions. In the same way, the statistical properties of the speckle fields, usually treated as a separate subject matter, are also integrated in the theory, thus providing a comprehensive knowledge of the qualitative features of speckle interferometry methods, otherwise difficult to understand

  15. Theoretical investigations on dual-beam illumination electronic speckle pattern interferometry

    Goudemand, Nicolas

    2006-07-01

    Contrary to what is found in most of the existing scientific literature, where a specific frame is developed, the theory of speckle interferometry is (conveniently) presented here as a particular case of the more general theory of holographic interferometry. In addition to the intellectual benefit of dealing with a single unified theory, this brings about many advantages when it comes to discuss fundamental topics such as the three-dimensional evolution of the complex amplitude of the diffuse optical wavefronts, the degree of approximation of the leading formulas, the loss of fringe contrast, the decorrelation effects, the real influence of the terms generally neglected in out-of-focus regions. In the same way, the statistical properties of the speckle fields, usually treated as a separate subject matter, are also integrated in the theory, thus providing a comprehensive knowledge of the qualitative features of speckle interferometry methods, otherwise difficult to understand.

  16. Using high resolution satellite multi-temporal interferometry for landslide hazard detection in tropical environments: the case of Haiti

    Wasowski, Janusz; Nutricato, Raffaele; Nitti, Davide Oscar; Bovenga, Fabio; Chiaradia, Maria Teresa; Piard, Boby Emmanuel; Mondesir, Philemon

    2015-04-01

    Synthetic aperture radar (SAR) multi-temporal interferometry (MTI) is one of the most promising satellite-based remote sensing techniques for fostering new opportunities in landslide hazard detection and assessment. MTI is attractive because it can provide very precise quantitative information on slow slope displacements of the ground surface over huge areas with limited vegetation cover. Although MTI is a mature technique, we are only beginning to realize the benefits of the high-resolution imagery that is currently acquired by the new generation radar satellites (e.g., COSMO-SkyMed, TerraSAR-X). In this work we demonstrate the potential of high resolution X-band MTI for wide-area detection of slope instability hazards even in tropical environments that are typically very harsh (eg. coherence loss) for differential interferometry applications. This is done by presenting an example from the island of Haiti, a tropical region characterized by dense and rapidly growing vegetation, as well as by significant climatic variability (two rainy seasons) with intense precipitation events. Despite the unfavorable setting, MTI processing of nearly 100 COSMO-SkyMed (CSK) mages (2011-2013) resulted in the identification of numerous radar targets even in some rural (inhabited) areas thanks to the high resolution (3 m) of CSK radar imagery, the adoption of a patch wise processing SPINUA approach and the presence of many man-made structures dispersed in heavily vegetated terrain. In particular, the density of the targets resulted suitable for the detection of some deep-seated and shallower landslides, as well as localized, very slow slope deformations. The interpretation and widespread exploitation of high resolution MTI data was facilitated by Google EarthTM tools with the associated high resolution optical imagery. Furthermore, our reconnaissance in situ checks confirmed that MTI results provided useful information on landslides and marginally stable slopes that can represent a

  17. A Transportable Gravity Gradiometer Based on Atom Interferometry

    Yu, Nan; Thompson, Robert J.; Kellogg, James R.; Aveline, David C.; Maleki, Lute; Kohel, James M.

    2010-01-01

    A transportable atom interferometer-based gravity gradiometer has been developed at JPL to carry out measurements of Earth's gravity field at ever finer spatial resolutions, and to facilitate high-resolution monitoring of temporal variations in the gravity field from ground- and flight-based platforms. Existing satellite-based gravity missions such as CHAMP and GRACE measure the gravity field via precise monitoring of the motion of the satellites; i.e. the satellites themselves function as test masses. JPL's quantum gravity gradiometer employs a quantum phase measurement technique, similar to that employed in atomic clocks, made possible by recent advances in laser cooling and manipulation of atoms. This measurement technique is based on atomwave interferometry, and individual laser-cooled atoms are used as drag-free test masses. The quantum gravity gradiometer employs two identical atom interferometers as precision accelerometers to measure the difference in gravitational acceleration between two points (Figure 1). By using the same lasers for the manipulation of atoms in both interferometers, the accelerometers have a common reference frame and non-inertial accelerations are effectively rejected as common mode noise in the differential measurement of the gravity gradient. As a result, the dual atom interferometer-based gravity gradiometer allows gravity measurements on a moving platform, while achieving the same long-term stability of the best atomic clocks. In the laboratory-based prototype (Figure 2), the cesium atoms used in each atom interferometer are initially collected and cooled in two separate magneto-optic traps (MOTs). Each MOT, consisting of three orthogonal pairs of counter-propagating laser beams centered on a quadrupole magnetic field, collects up to 10(exp 9) atoms. These atoms are then launched vertically as in an atom fountain by switching off the magnetic field and introducing a slight frequency shift between pairs of lasers to create a moving

  18. Dynamic Corneal Surface Mapping with Electronic Speckle Pattern Interferometry

    Iqbal, S.; Gualini, M. M. S.

    2013-06-01

    In view of the fast advancement in ophthalmic technology and corneal surgery, there is a strong need for the comprehensive mapping and characterization techniques for corneal surface. Optical methods with precision non-contact approaches have been found to be very useful for such bio measurements. Along with the normal mapping approaches, elasticity of corneal surface has an important role in its characterization and needs to be appropriately measured or estimated for broader diagnostics and better prospective surgical results, as it has important role in the post-op corneal surface reconstruction process. Use of normal corneal topographic devices is insufficient for any intricate analysis since these devices operate at relatively moderate resolution. In the given experiment, Pulsed Electronic Speckle Pattern Interferometry has been utilized along with an excitation mechanism to measure the dynamic response of the sample cornea. A Pulsed ESPI device has been chosen for the study because of its micron-level resolution and other advantages in real-time deformation analysis. A bovine cornea has been used as a sample in the subject experiment. The dynamic response has been taken on a chart recorder and it is observed that it does show a marked deformation at a specific excitation frequency, which may be taken as a characteristic elasticity parameter for the surface of that corneal sample. It was seen that outside resonance conditions the bovine cornea was not that much deformed. Through this study, the resonance frequency and the corresponding corneal deformations are mapped and plotted in real time. In these experiments, data was acquired and processed by FRAMES plus computer analysis system. With some analysis of the results, this technique can help us to refine a more detailed corneal surface mathematical model and some preliminary work was done on this. Such modelling enhancements may be useful for finer ablative surgery planning. After further experimentation

  19. Geodesy and astrometry by transatlantic long base line interferometry

    Cannon, W.H.; Langley, R.B.; Petrachenko, W.T.; Kouba, J.

    1979-01-01

    We report geodetic and astrometric results from the analysis of fringe frequency observations from a series of three long base line interferometry (LBI) experiments carried out in 1973 between the 46-m antenna of the Algonquin Radio Observatory, Lake Traverse, Canada, and the 25-m antenna at Chilbolton Field Station, Chilbolton, England. The rms deviation from the mean of the estimates of the length and orientation of the 5251-km equatorial component of the base line from all three experiments is 1.05-m and 0.015'', respectively. The experiments also yielded positions of five extragalactic radio sources. The reported positions, each of which is from only a single experiment, have uncertainties of about 0.2'' in declination (except for low declination sources) and about 0.01 s in right ascension. The LBI determination of the length and orientation of the equatorial component of the base line is compared to the corresponding values derived from Naval Weapons Laboratory 9D (NWL-9D) coorinates for the antennae. The two length measurements agree in scale within quoted experimental errors; however, the NWL-9D coordinate frame is found to be rotated 0.867'' +- 0.1'' to the east relative to the average terrestrial frame of the Bureau Internationale de l'Heure (BIH),(LBI coordinate frame). This is in good agreement with the expected misalignment of 0.65'' +- 0.2''. The differences in the rates of the clocks used at each end of the base line were also determined and compared to Loran-C observations

  20. MEGARA Optics: Sub-aperture Stitching Interferometry for Large Surfaces

    Aguirre-Aguirre, Daniel; Carrasco, Esperanza; Izazaga-Pérez, Rafael; Páez, Gonzalo; Granados-Agustín, Fermín; Percino-Zacarías, Elizabeth; Gil de Paz, Armando; Gallego, Jesús; Iglesias-Páramo, Jorge; Villalobos-Mendoza, Brenda

    2018-04-01

    In this work, we present a detailed analysis of sub-aperture interferogram stitching software to test circular and elliptical clear apertures with diameters and long axes up to 272 and 180 mm, respectively, from the Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía (MEGARA). MEGARA is a new spectrograph for the Gran Telescopio Canarias (GTC). It offers a resolution between 6000 and 20000 via the use of volume phase holographic gratings. It has an integral field unit and a set of robots for multi-object spectroscopy at the telescope focal plane. The output end of the fibers forms the spectrograph pseudo-slit. The fixed geometry of the collimator and camera configuration requires prisms in addition to the flat windows of the volume phase holographic gratings. There are 73 optical elements of large aperture and high precision manufactured in Mexico at the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) and the Centro de Investigaciones en Óptica (CIO). The principle of stitching interferometry is to divide the surface being tested into overlapping small sections, which allows an easier analysis (Kim & Wyant 1981). This capability is ideal for non-contact tests for unique and large optics as required by astronomical instruments. We show that the results obtained with our sub-aperture stitching algorithm were consistent with other methods that analyze the entire aperture. We used this method to analyze the 24 MEGARA prisms that could not be tested otherwise. The instrument has been successfully commissioned at GTC in all the spectral configurations. The fulfillment of the irregularity specifications was one of the necessary conditions to comply with the spectral requirements.

  1. The effects of orbital motion on LISA time delay interferometry

    Cornish, Neil J; Hellings, Ronald W

    2003-01-01

    In an effort to eliminate laser phase noise in laser interferometer spaceborne gravitational wave detectors, several combinations of signals have been found that allow the laser noise to be cancelled out while gravitational wave signals remain. This process is called time delay interferometry (TDI). In the papers that defined the TDI variables, their performance was evaluated in the limit that the gravitational wave detector is fixed in space. However, the performance depends on certain symmetries in the armlengths that are available if the detector is fixed in space, but that will be broken in the actual rotating and flexing configuration produced by the LISA orbits. In this paper we investigate the performance of these TDI variables for the real LISA orbits. First, addressing the effects of rotation, we verify Daniel Shaddock's result that the Sagnac variables α (t), β (t) and γ (t) will not cancel out the laser phase noise, and we also find the same result for the symmetric Sagnac variable ζ (t). The loss of the latter variable would be particularly unfortunate since this variable also cancels out gravitational wave signal, allowing instrument noise in the detector to be isolated and measured. Fortunately, we have found a set of more complicated TDI variables, which we call Δ Sagnac variables, one of which accomplishes the same goal as ζ (t) to good accuracy. Finally, however, as we investigate the effects of the flexing of the detector arms due to non-circular orbital motion, we show that all variables, including the interferometer variables, X(t), Y(t) and Z(t), which survive the rotation-induced loss of direction symmetry, will not completely cancel laser phase noise when the armlengths are changing with time. This unavoidable problem will place a stringent requirement on laser stability of ∼5 Hz Hz -1/2

  2. MULTI-TEMPORAL SAR INTERFEROMETRY FOR LANDSLIDE MONITORING

    R. Dwivedi

    2016-06-01

    Full Text Available In the past few years, SAR Interferometry specially InSAR and D-InSAR were extensively used for deformation monitoring related applications. Due to temporal and spatial decorrelation in dense vegetated areas, effectiveness of InSAR and D-InSAR observations were always under scrutiny. Multi-temporal InSAR methods are developed in recent times to retrieve the deformation signal from pixels with different scattering characteristics. Presently, two classes of multi-temporal InSAR algorithms are available- Persistent Scatterer (PS and Small Baseline (SB methods. This paper discusses the Stanford Method for Persistent Scatterer (StaMPS based PS-InSAR and the Small Baselines Subset (SBAS techniques to estimate the surface deformation in Tehri dam reservoir region in Uttarkhand, India. Both PS-InSAR and SBAS approaches used sixteen ENVISAT ASAR C-Band images for generating single master and multiple master interferograms stack respectively and their StaMPS processing resulted in time series 1D-Line of Sight (LOS mean velocity maps which are indicative of deformation in terms of movement towards and away from the satellites. From 1D LOS velocity maps, localization of landslide is evident along the reservoir rim area which was also investigated in the previous studies. Both PS-InSAR and SBAS effectively extract measurement pixels in the study region, and the general results provided by both approaches show a similar deformation pattern along the Tehri reservoir region. Further, we conclude that StaMPS based PS-InSAR method performs better in terms of extracting more number of measurement pixels and in the estimation of mean Line of Sight (LOS velocity as compared to SBAS method. It is also proposed to take up a few major landslides area in Uttarakhand for slope stability assessment.

  3. Sensor influence in digital 3λ holographic interferometry

    Desse, J M; Picart, P; Tankam, P

    2011-01-01

    In digital holographic interferometry, the resolution of the reconstructed hologram depends on the pixel size and pixel number of the sensor used for recording. When different wavelengths are simultaneously used as a luminous source for the interferometer, the shape and the overlapping of three filters of a color sensor strongly influence the three reconstructed images. This problem can be directly visualized in 2D Fourier planes on red, green and blue channels. To better understand this problem and to avoid parasitic images generated at the reconstruction, three different sensors have been tested: a CCD sensor equipped with a Bayer filter, a Foveon sensor and a 3CCD sensor. The first one is a Bayer mosaic where one half of the pixels detect the green color and only one-quarter detect the red or blue color. As the missing data are interpolated among color detection positions, offsets and artifacts are generated. The second one is a specific sensor constituted with three stacked photodiode layers. Its technology is different from that of the classical color mosaic sensor because each pixel location detects the three colors simultaneously. So, the three colors are recorded simultaneously with identical spatial resolution, which corresponds to the spatial resolution of the sensor. However, the spectral curve of the sensor is large along each wavelength since the color segmentation is based on the penetration depth of the photons in silicon. Finally, with a 3CCD sensor, each image is recorded on three different sensors with the same resolution. In order to test the sensor influence, we have developed a specific optical bench which allows the near wake flow around a circular cylinder at Mach 0.45 to be characterized. Finally, best results have been obtained with the 3CDD sensor

  4. Quantum interferometry with multiports: entangled photons in optical fibres

    Reck, M. H. A.

    1996-07-01

    This thesis is the result of theoretical and experimental work on the physics of optical multiports, which are the logical generalization of the beam splitter in classical and quantum optics. The experimental results are discussed in the context of Bell's inequalities and the physics of entanglement. The theoretical results show that multiport interferometers can be used to realize any discrete unitary transformation operating on modes of a classical or a quantum radiation field. Tests of a Bell-type inequality for higher-dimensional entangled states are thus possible using entangled photon pairs from a parametric downconversion source. The experimental work measured the nonclassical interferences at the fiber-optical three-way beam splitters (tritters) and three-path fiber interferometers. An experiment with a three-path all-fiber interferometer with HeNe laser light revealed the typical features of multipath interferometry. In another experiment, entangled photon pairs from the spontaneous parametric downconversion process were used to demonstrate a purely quantum effect, the antibunching of photon pairs at the output of an integrated fiber multiport. In the main experiment, time-energy entanglement of photon pairs from a parametric downconversion source in two threepath interferometers was used to built the first realization of an entangled three-state system. The interferences measured in this experiment are the first demonstration of two-photon three-path interferences. The quantum and classical pictures of the experiment are discussed giving an outlook to new experiments. Technical details about the experiments, a MATHEMATICA program for the design of unitary interferometers, some calculations, and photographs of type-II downconversion light are included in the appendices. (author)

  5. Ka-band SAR interferometry studies for the SWOT mission

    Fernandez, D. E.; Fu, L.; Rodriguez, E.; Hodges, R.; Brown, S.

    2008-12-01

    The primary objective of the NRC Decadal Survey recommended SWOT (Surface Water and Ocean Topography) Mission is to measure the water elevation of the global oceans, as well as terrestrial water bodies (such as rivers, lakes, reservoirs, and wetlands), to answer key scientific questions on the kinetic energy of ocean circulation, the spatial and temporal variability of the world's surface freshwater storage and discharge, and to provide societal benefits on predicting climate change, coastal zone management, flood prediction, and water resources management. The SWOT mission plans to carry the following suite of microwave instruments: a Ka-band interferometer, a dual-frequency nadir altimeter, and a multi-frequency water-vapor radiometer dedicated to measuring wet tropospheric path delay to correct the radar measurements. We are currently funded by the NASA Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) to reduce the risk of the main technological drivers of SWOT, by addressing the following technologies: the Ka-band radar interferometric antenna design, the on-board interferometric SAR processor, and the internally calibrated high-frequency radiometer. The goal is to significantly enhance the readiness level of the new technologies required for SWOT, while laying the foundations for the next-generation missions to map water elevation for studying Earth. The first two technologies address the challenges of the Ka-band SAR interferometry, while the high- frequency radiometer addresses the requirement for small-scale wet tropospheric corrections for coastal zone applications. In this paper, we present the scientific rational, need and objectives behind these technology items currently under development.

  6. Landslide Activity Maps Generation by Means of Persistent Scatterer Interferometry

    Silvia Bianchini

    2013-11-01

    Full Text Available In this paper a methodology is proposed to elaborate landslide activity maps through the use of PS (Persistent Scatterer data. This is illustrated through the case study of Tramuntana Range in the island of Majorca (Spain, where ALOS (Advanced Land Observing Satellite images have been processed through a Persistent Scatterer Interferometry (PSI technique during the period of 2007–2010. The landslide activity map provides, for every monitored landslide, an assessment of the PS visibility according to the relief, land use, and satellite acquisition parameters. Landslide displacement measurements are projected along the steepest slope, in order to compare landslide velocities with different slope orientations. Additionally, a ground motion activity map is also generated, based on active PS clusters not included within any known landslide phenomenon, but even moving, potentially referred to unmapped landslides or triggered by other kinds of geomorphological processes. In the Tramuntana range, 42 landslides were identified as active, four as being potential to produce moderate damage, intersecting the road Ma-10, which represents the most important road of the island and, thus, the main element at risk. In order to attest the reliability of measured displacements to represent landslide dynamics, a confidence degree evaluation is proposed. In this test site, seven landslides exhibit a high confidence degree, medium for 93 of them, and low for 51. A low confidence degree was also attributed to 615 detected active clusters with a potential to cause moderate damage, as their mechanism of the triggering cause is unknown. From this total amount, 18 of them intersect the Ma-10, representing further potentially hazardous areas. The outcomes of this work reveal the usefulness of landslide activity maps for environmental planning activities, being exportable to other radar data and different geomorphological settings.

  7. Metapopulation extinction risk: dispersal's duplicity.

    Higgins, Kevin

    2009-09-01

    Metapopulation extinction risk is the probability that all local populations are simultaneously extinct during a fixed time frame. Dispersal may reduce a metapopulation's extinction risk by raising its average per-capita growth rate. By contrast, dispersal may raise a metapopulation's extinction risk by reducing its average population density. Which effect prevails is controlled by habitat fragmentation. Dispersal in mildly fragmented habitat reduces a metapopulation's extinction risk by raising its average per-capita growth rate without causing any appreciable drop in its average population density. By contrast, dispersal in severely fragmented habitat raises a metapopulation's extinction risk because the rise in its average per-capita growth rate is more than offset by the decline in its average population density. The metapopulation model used here shows several other interesting phenomena. Dispersal in sufficiently fragmented habitat reduces a metapopulation's extinction risk to that of a constant environment. Dispersal between habitat fragments reduces a metapopulation's extinction risk insofar as local environments are asynchronous. Grouped dispersal raises the effective habitat fragmentation level. Dispersal search barriers raise metapopulation extinction risk. Nonuniform dispersal may reduce the effective fraction of suitable habitat fragments below the extinction threshold. Nonuniform dispersal may make demographic stochasticity a more potent metapopulation extinction force than environmental stochasticity.

  8. Precise signal amplitude retrieval for a non-homogeneous diagnostic beam using complex interferometry approach

    Krupka, Michal; Kálal, Milan; Dostál, Jan; Dudžák, Roman; Juha, Libor

    2017-01-01

    Roč. 12, August (2017), č. článku C08012. ISSN 1748-0221. [European Conference on Plasma Diagnostics (ECPD2017)/2./. Bordeaux, 18.04.2017-21.04.2017] R&D Projects: GA MŠk(CZ) LM2015083 Institutional support: RVO:61389021 Keywords : Image processing * Interferometry * Plasma diagnostics - interferometry * Spectroscopy and imaging Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: 2.11 Other engineering and technologies Impact factor: 1.220, year: 2016

  9. Heterodyne Interferometry in InfraRed at OCA-Calern Observatory in the seventies

    Gay, J.; Rabbia, Y.

    2014-04-01

    We report on various works carried four decades ago, so as to develop Heterodyne Interferometry in InfraRed (10 μm) at Calern Observatory (OCA, France), by building an experiment, whose the acronym "SOIRDETE" means "Synthese d'Ouverture en InfraRouge par Detection hETErodyne". Scientific and technical contexts by this time are recalled, as well as basic principles of heterodyne interferometry. The preliminary works and the SOIRDETE experiment are briefly described. Short comments are given in conclusion regarding the difficulties which have prevented the full success of the SOIRDETE experiment.

  10. Heisenberg-limited interferometry with pair coherent states and parity measurements

    Gerry, Christopher C.; Mimih, Jihane

    2010-01-01

    After reviewing parity-measurement-based interferometry with twin Fock states, which allows for supersensitivity (Heisenberg limited) and super-resolution, we consider interferometry with two different superpositions of twin Fock states, namely, two-mode squeezed vacuum states and pair coherent states. This study is motivated by the experimental challenge of producing twin Fock states on opposite sides of a beam splitter. We find that input two-mode squeezed states, while allowing for Heisenberg-limited sensitivity, do not yield super-resolutions, whereas both are possible with input pair coherent states.

  11. Relativistic plasma dispersion functions

    Robinson, P.A.

    1986-01-01

    The known properties of plasma dispersion functions (PDF's) for waves in weakly relativistic, magnetized, thermal plasmas are reviewed and a large number of new results are presented. The PDF's required for the description of waves with small wave number perpendicular to the magnetic field (Dnestrovskii and Shkarofsky functions) are considered in detail; these functions also arise in certain quantum electrodynamical calculations involving strongly magnetized plasmas. Series, asymptotic series, recursion relations, integral forms, derivatives, differential equations, and approximations for these functions are discussed as are their analytic properties and connections with standard transcendental functions. In addition a more general class of PDF's relevant to waves of arbitrary perpendicular wave number is introduced and a range of properties of these functions are derived

  12. Characterization of hidden defects of an original XVI century painting on wood by Electronic Speckle Pattern Interferometry (Electronic Speckle Pattern Interferometry survey on a wooden painting)

    Arena, G.

    2015-01-01

    Electronic Speckle Pattern Interferometry, a non-contact and nondestructive optical diagnostic technique, was employed for evaluating the conservation state of a XVI century painting on wood. The whole structure alterations, induced by the laboratory temperature and relative humidity variations, were evaluated. Long-term analysis, by sequential recording and subsequent off-line processing of the fringes progression, was carried out. Local flaws and hidden detachments of pictorial layers from the support, which could not be recognized by traditional art-restorer survey methods, were also easily revealed. In such a case, a simple measurement approach was utilized, with the aim to get a user-friendly method for art conservators. The results demonstrate that the interferometry method can largely improve the traditional art conservation survey techniques.

  13. Statistical Thermodynamics of Disperse Systems

    Shapiro, Alexander

    1996-01-01

    Principles of statistical physics are applied for the description of thermodynamic equilibrium in disperse systems. The cells of disperse systems are shown to possess a number of non-standard thermodynamic parameters. A random distribution of these parameters in the system is determined....... On the basis of this distribution, it is established that the disperse system has an additional degree of freedom called the macro-entropy. A large set of bounded ideal disperse systems allows exact evaluation of thermodynamic characteristics. The theory developed is applied to the description of equilibrium...

  14. Geometry of physical dispersion relations

    Raetzel, Dennis; Rivera, Sergio; Schuller, Frederic P.

    2011-01-01

    To serve as a dispersion relation, a cotangent bundle function must satisfy three simple algebraic properties. These conditions are derived from the inescapable physical requirements that local matter field dynamics must be predictive and allow for an observer-independent notion of positive energy. Possible modifications of the standard relativistic dispersion relation are thereby severely restricted. For instance, the dispersion relations associated with popular deformations of Maxwell theory by Gambini-Pullin or Myers-Pospelov are not admissible. Dispersion relations passing the simple algebraic checks derived here correspond to physically admissible Finslerian refinements of Lorentzian geometry.

  15. A gripe suína na Wikipédia em português: análise da dinâmica de edições e qualificação do conteúdo de dois artigos

    Bernardo Esteves Gonçalves da Costa; Carlos Frederico de Brito d'Andréa

    2011-01-01

    Este artigo tem como objetivo analisar e comparar a edição colaborativa de dois artigos sobre pandemia de gripe A (H1N1) — ou gripe suína — na Wikipédia em português. Monitoramos as edições feitas nos dois artigos ao longo de um mês após a criação de ambos, em 25 de abril de 2009. Caracterizamos o processo de edição dos textos e a dinâmica de interações entre os editores e, de forma complementar, analisamos seu conteúdo a partir de três critérios: autoridade, verificabilidade e atualidade....

  16. Avaliação da anotação semântica do PALAVRAS e sua pós-edição manual para o Corpus Summ-it

    Élen Cátia Tomazela

    2011-01-01

    Full Text Available Este artigo apresenta uma avaliação da anotação semântica automática do parser PALAVRAS e sua pós-edição manual para um corpus de textos em português – o Corpus Summ-it. Essa pós-edição visou ao aprimoramento de um modelo linguístico para a sumarização automática de textos e buscou atribuir  etiquetas semânticas mais adequadas aos itens lexicais, comparadas às empregadas pelo parser. Essa tarefa foi realizada por linguistas e os casos problemáticos são apresentados neste artigo, os quais levam a considerações sobre o próprio modelo de etiquetagem do PALAVRAS. O corpus revisado estará disponível para a comunidade e poderá ser útil para várias aplicações de Processamento de Línguas Naturais.

  17. Avaliação da anotação semântica do PALAVRAS e sua pós-edição manual para o Corpus Summ-it

    Élen Cátia Tomazela

    2011-01-01

    Full Text Available Este artigo apresenta uma avaliação da anotação semântica automática do parser PALAVRAS e sua pós-edição manual para um corpus de textos em português – o Corpus Summ-it. Essa pós-edição visou ao aprimoramento de um modelo linguístico para a sumarização automática de textos e buscou atribuir  etiquetas semânticas mais adequadas aos itens lexicais, comparadas às empregadas pelo parser. Essa tarefa foi realizada por linguistas e os casos problemáticos são apresentados neste artigo, os quais levam a considerações sobre o próprio modelo de etiquetagem do PALAVRAS. O corpus revisado estará disponível para a comunidade e poderá ser útil para várias aplicações de Processamento de Línguas Naturais.

  18. "Economia e sociedade": a herança de Max Weber à luz da edição de sua Obra completa (MWG "Economy and society": Max Weber's legacy following the publication of his Complete works (MWG

    M. Rainer Lepsius

    2012-01-01

    Full Text Available O artigo relata o entendimento atual do conjunto de textos conhecido como Economia e sociedade, procurando esclarecer em que consistia originalmente; como foi organizado nas edições anteriores por Marianne Weber e Johannes Winckelmann; como foi tratado no âmbito da nova edição da MWG. Para tanto, procura indicar como Max Weber situava os diversos textos, as diversas versões e fases de concepção e composição desses escritos. A partir daí, sistematiza os principais aspectos dos textos evidenciados na MWG, assim como os principais campos de discussão que se abrem para a pesquisa, em especial a sociologia econômica.The article reviews the current understanding of the set of texts known as Economy and Society, looking to identify the original content, how these texts were edited in previous editions by Marianne Weber and Johannes Winckelmann, and how they have been dealt with in the new edition of the MWG. These aims in mind, the text looks to show how Max Weber himself situated the various texts, including the different versions and phases of conception and composition of the writings. The article then summarizes the main aspects of the works, as evinced in the MWG, as well as the principal fields of discussion opened up for research, especially in economic sociology.

  19. O, 5 mm: a nova edição brasileira de Problemas da poética de Dostoiévski/0.5 mm: The New Brazilian Edition of Problems of Dostoevsky’s Poetics

    Adriana Pucci Penteado de Faria e Silva

    2011-11-01

    Full Text Available RESUMO: Neste artigo, retomo brevemente a história da recepção de Problemas da poética de Dostoiévski, de Mikhail Bakhtin, no Brasil, estabelecendo alguns paralelos com aspectos da recepção da obra na Itália, na França e nos Estados Unidos, para, então, descrever os acréscimos da nova edição brasileira e analisar, considerando a relevância da obra para os estudos da linguagem, algumas modificações efetuadas pelo tradutor Paulo Bezerra na quarta edição da obra, lançada em 2008. ABSTRACT: In this article I briefly review the history of the Brazilian reception of Mikhail Bakhtin’s Problems of Dostoevsky’s Poetics, establishing a few parallels with aspects of this work’s reception in Italy, France, and the United States in order to describe the additions made to the new Brazilian edition and, considering the relevance of this work to Language Studies, analyze some changes proposed by translator Paulo Bezerra in its

  20. (Desmetaforizando significados na pós-edição: um estudo exploratório do esforço despendido por estudantes de tradução

    Adriana Silvina Pagano

    2014-03-01

    Full Text Available Este artigo examina dados de um experimento-piloto e tem por objetivo investigar o esforço despendido por estudantes de tradução em uma tarefa de pós-edição, a partir da análise de pausas e movimentos recursivos registrados durante a produção textual em tempo real para instâncias gramaticalmente metafóricas (cf. HALLIDAY,1998. O estudo contempla o processo e o produto da pós-edição de três alunos de pós-graduação em tradução. Para se proceder à análise, foram observados os registros de uso de teclado e movimentos de cursor mapeados pelo programa Translog 2006 para a produção textual em tempo real. Como resultado, verificou-se um grande esforço para se processar algumas instâncias gramaticalmente metafóricas, sendo que esse esforço não resultou em uma maior adequação dos significados produzidos.

  1. Dispersion bias, dispersion effect, and the aerosol-cloud conundrum

    Liu Yangang; Daum, Peter H; Guo Huan; Peng Yiran

    2008-01-01

    This work examines the influences of relative dispersion (the ratio of the standard deviation to the mean radius of the cloud droplet size distribution) on cloud albedo and cloud radiative forcing, derives an analytical formulation that accounts explicitly for the contribution from droplet concentration and relative dispersion, and presents a new approach to parameterize relative dispersion in climate models. It is shown that inadequate representation of relative dispersion in climate models leads to an overestimation of cloud albedo, resulting in a negative bias of global mean shortwave cloud radiative forcing that can be comparable to the warming caused by doubling CO 2 in magnitude, and that this dispersion bias is likely near its maximum for ambient clouds. Relative dispersion is empirically expressed as a function of the quotient between cloud liquid water content and droplet concentration (i.e., water per droplet), yielding an analytical formulation for the first aerosol indirect effect. Further analysis of the new expression reveals that the dispersion effect not only offsets the cooling from the Twomey effect, but is also proportional to the Twomey effect in magnitude. These results suggest that unrealistic representation of relative dispersion in cloud parameterization in general, and evaluation of aerosol indirect effects in particular, is at least in part responsible for several outstanding puzzles of the aerosol-cloud conundrum: for example, overestimation of cloud radiative cooling by climate models compared to satellite observations; large uncertainty and discrepancy in estimates of the aerosol indirect effect; and the lack of interhemispheric difference in cloud albedo.

  2. Sources of Artefacts in Synthetic Aperture Radar Interferometry Data Sets

    Becek, K.; Borkowski, A.

    2012-07-01

    In recent years, much attention has been devoted to digital elevation models (DEMs) produced using Synthetic Aperture Radar Interferometry (InSAR). This has been triggered by the relative novelty of the InSAR method and its world-famous product—the Shuttle Radar Topography Mission (SRTM) DEM. However, much less attention, if at all, has been paid to sources of artefacts in SRTM. In this work, we focus not on the missing pixels (null pixels) due to shadows or the layover effect, but rather on outliers that were undetected by the SRTM validation process. The aim of this study is to identify some of the causes of the elevation outliers in SRTM. Such knowledge may be helpful to mitigate similar problems in future InSAR DEMs, notably the ones currently being developed from data acquired by the TanDEM-X mission. We analysed many cross-sections derived from SRTM. These cross-sections were extracted over the elevation test areas, which are available from the Global Elevation Data Testing Facility (GEDTF) whose database contains about 8,500 runways with known vertical profiles. Whenever a significant discrepancy between the known runway profile and the SRTM cross-section was detected, a visual interpretation of the high-resolution satellite image was carried out to identify the objects causing the irregularities. A distance and a bearing from the outlier to the object were recorded. Moreover, we considered the SRTM look direction parameter. A comprehensive analysis of the acquired data allows us to establish that large metallic structures, such as hangars or car parking lots, are causing the outliers. Water areas or plain wet terrains may also cause an InSAR outlier. The look direction and the depression angle of the InSAR system in relation to the suspected objects influence the magnitude of the outliers. We hope that these findings will be helpful in designing the error detection routines of future InSAR or, in fact, any microwave aerial- or space-based survey. The

  3. SOURCES OF ARTEFACTS IN SYNTHETIC APERTURE RADAR INTERFEROMETRY DATA SETS

    K. Becek

    2012-07-01

    Full Text Available In recent years, much attention has been devoted to digital elevation models (DEMs produced using Synthetic Aperture Radar Interferometry (InSAR. This has been triggered by the relative novelty of the InSAR method and its world-famous product—the Shuttle Radar Topography Mission (SRTM DEM. However, much less attention, if at all, has been paid to sources of artefacts in SRTM. In this work, we focus not on the missing pixels (null pixels due to shadows or the layover effect, but rather on outliers that were undetected by the SRTM validation process. The aim of this study is to identify some of the causes of the elevation outliers in SRTM. Such knowledge may be helpful to mitigate similar problems in future InSAR DEMs, notably the ones currently being developed from data acquired by the TanDEM-X mission. We analysed many cross-sections derived from SRTM. These cross-sections were extracted over the elevation test areas, which are available from the Global Elevation Data Testing Facility (GEDTF whose database contains about 8,500 runways with known vertical profiles. Whenever a significant discrepancy between the known runway profile and the SRTM cross-section was detected, a visual interpretation of the high-resolution satellite image was carried out to identify the objects causing the irregularities. A distance and a bearing from the outlier to the object were recorded. Moreover, we considered the SRTM look direction parameter. A comprehensive analysis of the acquired data allows us to establish that large metallic structures, such as hangars or car parking lots, are causing the outliers. Water areas or plain wet terrains may also cause an InSAR outlier. The look direction and the depression angle of the InSAR system in relation to the suspected objects influence the magnitude of the outliers. We hope that these findings will be helpful in designing the error detection routines of future InSAR or, in fact, any microwave aerial- or space

  4. Analysis of error functions in speckle shearing interferometry

    Wan Saffiey Wan Abdullah

    2001-01-01

    Electronic Speckle Pattern Shearing Interferometry (ESPSI) or shearography has successfully been used in NDT for slope (∂w/ (∂x and / or (∂w/ (∂y) measurement while strain measurement (∂u/ ∂x, ∂v/ ∂y, ∂u/ ∂y and (∂v/ (∂x) is still under investigation. This method is well accepted in industrial applications especially in the aerospace industry. Demand of this method is increasing due to complexity of the test materials and objects. ESPSI has successfully performed in NDT only for qualitative measurement whilst quantitative measurement is the current aim of many manufacturers. Industrial use of such equipment is being completed without considering the errors arising from numerous sources, including wavefront divergence. The majority of commercial systems are operated with diverging object illumination wave fronts without considering the curvature of the object illumination wavefront or the object geometry, when calculating the interferometer fringe function and quantifying data. This thesis reports the novel approach in quantified maximum phase change difference analysis for derivative out-of-plane (OOP) and in-plane (IP) cases that propagate from the divergent illumination wavefront compared to collimated illumination. The theoretical of maximum phase difference is formulated by means of three dependent variables, these being the object distance, illuminated diameter, center of illuminated area and camera distance and illumination angle. The relative maximum phase change difference that may contributed to the error in the measurement analysis in this scope of research is defined by the difference of maximum phase difference value measured by divergent illumination wavefront relative to the maximum phase difference value of collimated illumination wavefront, taken at the edge of illuminated area. Experimental validation using test objects for derivative out-of-plane and derivative in-plane deformation, using a single illumination wavefront

  5. On the focusing conditions in time-reversed acoustics, seismic interferometry, and Marchenko imaging

    Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.; Vasconcelos, I.; Van Manen, D.J.; Ravasi, M.

    2014-01-01

    Despite the close links between the fields of time-reversed acoustics, seismic interferometry and Marchenko imaging, a number of subtle differences exist. This paper reviews the various focusing conditions of these methods, the causality/acausality aspects of the corresponding focusing wavefields,

  6. First Beam Test of Nanometer Spot Size Monitor Using Laser Interferometry

    Walz, D

    2003-01-01

    The nanometer spot size monitor based on the laser interferometry (Laser-Compton Spot Size Monitor) has been tested in FFTB beam line at SLAC. A low emittance beam of 46 GeV electrons, provided by the two-mile linear accelerator, was focused into nanometer spot in the FFTB line, and its transverse dimensions were precisely measured by the spot size monitor.

  7. First Beam Test of Nanometer Spot Size Monitor Using Laser Interferometry

    Walz, Dieter R

    2003-01-01

    The nanometer spot size monitor based on the laser interferometry (Laser-Compton Spot Size Monitor) has been tested in FFTB beam line at SLAC. A low emittance beam of 46 GeV electrons, provided by the two-mile linear accelerator, was focused into nanometer spot in the FFTB line, and its transverse dimensions were precisely measured by the spot size monitor

  8. Inter-source seismic interferometry by multidimensional deconvolution (MDD) for borehole sources

    Liu, Y.; Wapenaar, C.P.A.; Romdhane, A.

    2014-01-01

    Seismic interferometry (SI) is usually implemented by crosscorrelation (CC) to retrieve the impulse response between pairs of receiver positions. An alternative approach by multidimensional deconvolution (MDD) has been developed and shown in various studies the potential to suppress artifacts due to

  9. Azimuthally sensitive Hanbury Brown-Twiss interferometry measured with the ALICE experiment

    Gramling, Johanna Lena

    2011-07-01

    Bose-Einstein correlations of identical pions emitted in high-energy particle collisions provide information about the size of the source region in space-time. If analyzed via HBT Interferometry in several directions with respect to the reaction plane, the shape of the source can be extracted. Hence, HBT Interferometry provides an excellent tool to probe the characteristics of the quark-gluon plasma possibly created in high-energy heavy-ion collisions. This thesis introduces the main theoretical concepts of particle physics, the quark gluon plasma and the technique of HBT interferometry. The ALICE experiment at the CERN Large Hadron Collider (LHC) is explained and the first azimuthallyintegrated results measured in Pb-Pb collisions at √(s{sub NN})=2.76 TeV with ALICE are presented. A detailed two-track resolution study leading to a global pair cut for HBT analyses has been performed, and a framework for the event plane determination has been developed. The results from azimuthally sensitive HBT interferometry are compared to theoretical models and previous measurements at lower energies. Oscillations of the transverse radii in dependence on the pair emission angle are observed, consistent with a source that is extended out-of-plane.

  10. Measurement of picometre non-linearity in an optical grating encoder using x-ray interferometry

    Yacoot, Andrew; Cross, Nigel

    2003-01-01

    X-ray interferometry has been used to characterize the non-linearity in an optical encoder displacement measuring system. Traceable measurements of the non-linearity have been made and an estimation of the uncertainty associated with the measurements is given. Cyclic errors with a magnitude of up to 50 pm and periodicity of the encoder system (128 nm) have been recorded.

  11. Direct measurements of air layer profiles under impacting droplets using high-speed color interferometry

    van der Veen, Roeland; Tran, Tuan; Lohse, Detlef; Sun, Chao

    2012-01-01

    A drop impacting on a solid surface deforms before the liquid makes contact with the surface. We directly measure the time evolution of the air layer profile under the droplet using high-speed color interferometry, obtaining the air layer thickness before and during the wetting process. Based on the

  12. Thermo-mechanical analysis of retro-reflectors for interferometry and polarimetry in W7-X

    Köppen, M.; Hirsch, M.; Ernst, J.; Vliegenthart, W.A.; Ye, M.Y.; Bykov, V.; Schauer, F.

    2011-01-01

    The stellarator Wendelstein 7-X (W7-X) is presently under construction at the Max-Planck-Institut für Plasmaphysik in Greifswald, Germany. The plasma density profile will be measured by two-colour interferometry where for each line of sight through the plasma the phase shifts of two far-infrared

  13. Preliminary interferometry measurements of a flow field around fluttering NACA0015 profile

    Vlček, Václav; Kozánek, Jan

    2011-01-01

    Roč. 56, č. 4 (2011), s. 379-387 ISSN 0001-7043 R&D Projects: GA ČR GA101/09/1522 Institutional research plan: CEZ:AV0Z20760514 Keywords : self-excited vibration * airfoil * aerodynamic tunnel * interferometry Subject RIV: BI - Acoustics http://journal.it.cas.cz

  14. On seismic interferometry, the generalized optical theorem, and the scattering matrix of a point scatterer

    Wapenaar, C.P.A.; Slob, E.C.; Snieder, R.

    2010-01-01

    We have analyzed the far-field approximation of the Green's function representation for seismic interferometry. By writing each of the Green's functions involved in the correlation process as a superposition of a direct wave and a scattered wave, the Green's function representation is rewritten as a

  15. Reflection imaging of the Moon's interior using deep-moonquake seismic interferometry

    Nishitsuji, Y.; Rowe, CA; Wapenaar, C.P.A.; Draganov, D.S.

    2016-01-01

    The internal structure of the Moon has been investigated over many years using a variety of seismic methods, such as travel time analysis, receiver functions, and tomography. Here we propose to apply body-wave seismic interferometry to deep moonquakes in order to retrieve zero-offset reflection

  16. Seismic interferometry by crosscorrelation and by multidimensional deconvolution: a systematic comparison

    Wapenaar, Kees; van der Neut, Joost; Ruigrok, Elmer; Draganov, Deyan; Hunziker, Jürg; Slob, Evert; Thorbecke, Jan; Snieder, Roel

    2011-06-01

    Seismic interferometry, also known as Green's function retrieval by crosscorrelation, has a wide range of applications, ranging from surface-wave tomography using ambient noise, to creating virtual sources for improved reflection seismology. Despite its successful applications, the crosscorrelation approach also has its limitations. The main underlying assumptions are that the medium is lossless and that the wavefield is equipartitioned. These assumptions are in practice often violated: the medium of interest is often illuminated from one side only, the sources may be irregularly distributed, and losses may be significant. These limitations may partly be overcome by reformulating seismic interferometry as a multidimensional deconvolution (MDD) process. We present a systematic analysis of seismic interferometry by crosscorrelation and by MDD. We show that for the non-ideal situations mentioned above, the correlation function is proportional to a Green's function with a blurred source. The source blurring is quantified by a so-called interferometric point-spread function which, like the correlation function, can be derived from the observed data (i.e. without the need to know the sources and the medium). The source of the Green's function obtained by the correlation method can be deblurred by deconvolving the correlation function for the point-spread function. This is the essence of seismic interferometry by MDD. We illustrate the crosscorrelation and MDD methods for controlled-source and passive-data applications with numerical examples and discuss the advantages and limitations of both methods.

  17. Using Airborne SAR Interferometry to Measure the Elevation of a Greenland Ice Cap

    Dall, Jørgen; Keller, K.; Madsen, S.N.

    2000-01-01

    A digital elevation model (DEM) of an ice cap in Greenland has been generated from airborne SAR interferometry data, calibrated with a new algorithm, and compared with airborne laser altimetry profiles and carrier-phase differential GPS measurements of radar reflectors deployed on the ice cap...... with GPS data and calibrated laser data....

  18. Speckle Interferometry with the McMath-Pierce East Auxiliary Telescope

    Harshaw, Richard; Ray, Jimmy; Douglass, David; Prause, Lori; Genet, Russell

    2015-09-01

    Engineering runs and tests on the McMath-Pierce 0.8 meter East Auxiliary telescope successfully configured the telescope for speckle interferometry observations of close visual double stars. This paper reports the procedure and results of the speckle analysis of four double stars.

  19. Electronic speckle pattern interferometry observation of brick–mortar interface behaviour under compression

    Vermeltfoort, A.T.; Martens, D.R.W; Zijl, van G.P.A.G.

    2007-01-01

    The brick–mortar interaction is important in the mechanical behaviour of masonry. It affects the load transfer considerably, as shown by detailed deformation measurements taken using electronic speckle pattern interferometry (ESPI), a laser speckle interference technique. A companion paper [Canadian

  20. Development of IR single mode optical fibers for DARWIN-nulling interferometry

    Chakkalakkal Abdulla, S.M.; Cheng, L.K.; Bosch, B. van den; Dijkhuizen, N.; Nieuwland, R.A.; Gielesen, W.L.M.; Lucas, J.; Boussard-Plédel, C.; Conseil, C.; Bureau, B.; Carmo, J.P. do

    2014-01-01

    The DARWIN mission aims to detect weak infra-red emission lines from distant orbiting earth-like planets using nulling interferometry. This requires filtering of wavefront errors using single mode waveguides operating at a wavelength range of 6.5-20 μm. This article describes the optical design of

  1. Quantification of the neutron dark-field imaging signal in grating interferometry

    Grünzweig, C.; Kopeček, Jaromír; Betz, B.; Kaestner, A.; Jefimovs, K.; Kohlbrecher, J.; Gasser, U.; Bunk, O.; David, C.; Lehmann, E.; Donath, T.; Pfeiffer, F.

    2012-01-01

    Roč. 88, č. 12 (2012), "125104-1"-"125104-6" ISSN 1098-0121 Institutional support: RVO:68378271 Keywords : neutron scattering (including small-angle scattering) * atom and neutron interferometry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.767, year: 2012

  2. Time-Lapse Monitoring of Subsurface Fluid Flow using Parsimonious Seismic Interferometry

    Hanafy, Sherif; Li, Jing; Schuster, Gerard T.

    2017-01-01

    of parsimonious seismic interferometry with the time-lapse mentoring idea with field examples, where we were able to record 30 different data sets within a 2-hour period. The recorded data are then processed to generate 30 snapshots that shows the spread of water

  3. Strain localization band width evolution by electronic speckle pattern interferometry strain rate measurement

    Guelorget, Bruno [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)], E-mail: bruno.guelorget@utt.fr; Francois, Manuel; Montay, Guillaume [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

    2009-04-15

    In this paper, electronic speckle pattern interferometry strain rate measurements are used to quantify the width of the strain localization band, which occurs when a sheet specimen is submitted to tension. It is shown that the width of this band decreases with increasing strain. Just before fracture, this measured width is about five times wider than the shear band and the initial sheet thickness.

  4. Tutorial on seismic interferometry : Part 1 — Basic principles and applications

    Wapenaar, C.P.A.; Draganov, D.S.; Snieder, R.; Campman, X.; Verdel, A.

    2010-01-01

    Seismic interferometry involves the crosscorrelation of responses at different receivers to obtain the Green's function between these receivers. For the simple situation of an impulsive plane wave propagating along the x-axis, the crosscorrelation of the responses at two receivers along the x-axis

  5. Evaluation of back scatter interferometry, a method for detecting protein binding in solution

    Jepsen, S. T.; Jørgensen, Thomas Martini; Zong, Weiyong

    2015-01-01

    Back Scatter Interferometry (BSI) has been proposed to be a highly sensitive and versatile refractive index sensor usable for analytical detection of biomarker and protein interactions in solution. However the existing literature on BSI lacks a physical explanation of why protein interactions in ...

  6. Monitoring Line-Infrastructure With Multisensor SAR Interferometry : Products and Performance Assessment Metrics

    Chang, L.; Dollevoet, R.P.B.J.; Hanssen, R.F.

    2018-01-01

    Satellite radar interferometry (InSAR) is an emerging technique to monitor the stability and health of line-infrastructure assets, such as railways, dams, and pipelines. However, InSAR is an opportunistic approach as the location and occurrence of its measurements (coherent scatterers) cannot be

  7. Landau-Zener-Stückelberg Interferometry of a Single Electronic Spin in a Noisy Environment

    Pu Huang

    2011-08-01

    Full Text Available We demonstrate quantum coherent control of single electronic spins in a nitron-vacancy center in diamond by exploiting and implementing the general concept of Landau-Zener-Stückelberg interferometry at room temperature. The interferometry manipulates an effective two-level system of electronic spins which are coupled to the nearby ^{14}N nuclear spin in the nitron-vacancy center as well as the nuclear spin bath in the diamond. With a microwave field to control the energy gap between the two levels and an AC field as the time-dependent driving field in Landau-Zener-Stückelberg interferometry, the interference pattern can be generated and controlled by controlling a number of parameters in the fields, corresponding to coherent control of the state of the electronic spins. In particular, the interference pattern is observed oscillating as a function of the frequency of the microwave field. Decays in the visibility of the interference pattern are also observed and well explained by numerical simulation which takes into account the thermal fluctuations arising from the nuclear bath. Therefore, our work also demonstrates that Landau-Zener-Stückelberg interferometry can be used for probing decoherence processes of electronic spins.

  8. Auroral electron time dispersion

    Kletzing, C.A.

    1989-01-01

    A sounding rocket flight was launched from Greenland in 1985 to study high latitude, early morning auroral physics. The payload was instrumented with electron and ion detectors, AC and DC electric field experiments, a plasma density experiment, and a magnetometer to measure the ambient field. The rocket was launched during disturbed conditions, when the polar cap was in a contracted state with visible aurora overhead. The electron data contained numerous signatures indicative of time-of-flight energy dispersion characterized by a coherent structure in which lower energy electrons arrived at the rocket after higher energy electrons. A model was constructed to explain this phenomena by the sudden application of a region of parallel electric field along a length of magnetic field line above the rocket. The model incorporates detector response and uses an altitudinal density profile based on auroral zone measurements. Three types of potential structures were tried: linear, quadratic and cubic. Of the three it was found that the cubic (electric field growing in a quadratic manner moving up the field line) produced the best fit to the data. The potential region was found to be approximately 1-2 R e in extent with the lower edge 3000-4000 km away from the rocket. The background electron temperature in the model which produced the best fit to the data was of the order of 15 eV

  9. Dispersal and migration

    Schwarz, C.

    2004-06-01

    Full Text Available Ringing of birds unveiled many aspects of avian migration and dispersal movements. However, there is even much more to be explored by the use of ringing and other marks. Dispersal is crucial in understanding the initial phase of migration in migrating birds as it is to understand patterns and processes of distribution and gene flow. So far, the analysis of migration was largely based on analysing spatial and temporal patters of recoveries of ringed birds. However, there are considerable biases and pitfalls in using recoveries due to spatial and temporal variation in reporting probabilities. Novel methods are required for future studies separating the confounding effects of spatial and temporal heterogeneity of recovery data and heterogeneity of the landscape as well. These novel approaches should aim a more intensive and novel use of the existing recovery data by taking advantage of, for instance, dynamic and multistate modeling, should elaborate schemes for future studies, and should also include other marks that allow a more rapid data collection, like telemetry, geolocation and global positioning systems, and chemical and molecular markers. The latter appear to be very useful in the delineating origin of birds and connectivity between breeding and non–breeding grounds. Many studies of migration are purely descriptive. However, King and Brooks (King & Brooks, 2004 examine if movement patterns of dolphins change after the introduction of a gillnet ban. Bayesian methods are an interesting approach to this problem as they provide a meaningful measure of the probability that such a change occurred rather than simple yes/no response that is often the result of classical statistical methods. However, the key difficulty of a general implementation of Bayesian methods is the complexity of the modelling —there is no general userfriendly package that is easily accessible to most scientists. Drake and Alisauskas (Drake & Alisauskas, 2004 examine the

  10. Progress in urban dispersion studies

    Batchvarova, E.; Gryning, Sven-Erik

    2006-01-01

    The present Study addresses recent achievements in better representation Of the urban area structure in meteorology and dispersion parameterisations. The setup and Main Outcome of several recent dispersion experiments in Urban areas and their use in model validation are discussed. The maximum con...

  11. Nest-mediated seed dispersal

    Robert J. Warren; Jason P. Love; Mark A. Bradford

    2017-01-01

    Many plant seeds travel on the wind and through animal ingestion or adhesion; however, an overlooked dispersal mode may lurk within those dispersal modes. Viable seeds may remain attached or embedded within materials birds gather for nest building. Our objective was to determine if birds inadvertently transport seeds when they forage for plant materials to...

  12. Definition of global dispersion coefficients

    Naff, R.L.

    1983-10-01

    For estimation of a global longitudinal dispersivity at the Gorleben site, data available primarily consist of suites of geophysical logs from wells penetrating the Quaternary aquifer. A length scale for the principle aquifer at Gorleben is to be found. Samples are to be taken separately to estimate the variance in hydraulic conductivity (Taylor Analysis, Fickian dispersion process). (DG)

  13. Tracking changes in volcanic systems with seismic Interferometry

    Haney, Matt; Alicia J. Hotovec-Ellis,; Bennington, Ninfa L.; Silvio De Angelis,; Clifford Thurber,

    2014-01-01

    use ambient noise tomography (ANT) to map the 3D structure of a volcanic interior (at Piton de la Fournaise). Subsequent studies have imaged volcanoes with ANT at Okmok (Masterlark et al. 2010), Toba (Stankiewicz et al. 2010), Katmai (Thurber et al. 2012), Asama (Nagaoka et al. 2012), Uturuncu (Jay et al. 2012), and Kilauea (Ballmer et al. 2013b). In addition, Ma et al. (2013) have imaged a scatterer in the volcanic region of southern Peru by applying array techniques to ambient noise correlations. Prior to and in tandem with the development of ANT, researchers discovered that repeating earthquakes, which often occur at volcanoes, could be used to monitor subtle time-dependent changes with a technique known as the doublet method or coda wave interferometry (CWI) (Poupinet et al. 1984; Roberts et al. 1992; Ratdomopurbo and Poupinet 1995; Snieder et al. 2002; Pandolfi et al. 2006; Wegler et al. 2006; Martini et al. 2009; Haney et al. 2009; De Angelis 2009; Nagaoka et al. 2010; Battaglia et al. 2012; Erdem and Waite 2005; Hotovec-Ellis et al. 2014). Chaput et al. (2012) have also used scattered waves from Strombolian eruption coda at Erebus volcano to image the reflectivity of the volcanic interior with body wave interferometry. However, CWI in its original form was limited in that repeating earthquakes, or doublets, were not always guaranteed to occur. With the widespread use of noise correlations in seismology following the groundbreaking work by Campillo and Paul (2003) and Shapiro et al. (2005), it became evident that the nature of the ambient seismic field, due to its oceanic origin, enabled the continuous monitoring of subtle, time-dependent changes at both fault zones (Wegler and Sens-Schönfelder 2007; Brenguier et al. 2008b; Wegler et al. 2009; Sawazaki et al. 2009; Tatagi et al. 2012) and volcanoes (Sens-Schönfelder and Wegler 2006; Brenguier et al. 2008a) without the need for repeating earthquakes. Seismic precursors to eruptions based on ambient noise we

  14. Dispersive detection of radio-frequency-dressed states

    Jammi, Sindhu; Pyragius, Tadas; Bason, Mark G.; Florez, Hans Marin; Fernholz, Thomas

    2018-04-01

    We introduce a method to dispersively detect alkali-metal atoms in radio-frequency-dressed states. In particular, we use dressed detection to measure populations and population differences of atoms prepared in their clock states. Linear birefringence of the atomic medium enables atom number detection via polarization homodyning, a form of common path interferometry. In order to achieve low technical noise levels, we perform optical sideband detection after adiabatic transformation of bare states into dressed states. The balanced homodyne signal then oscillates independently of field fluctuations at twice the dressing frequency, thus allowing for robust, phase-locked detection that circumvents low-frequency noise. Using probe pulses of two optical frequencies, we can detect both clock states simultaneously and obtain population difference as well as the total atom number. The scheme also allows for difference measurements by direct subtraction of the homodyne signals at the balanced detector, which should technically enable quantum noise limited measurements with prospects for the preparation of spin squeezed states. The method extends to other Zeeman sublevels and can be employed in a range of atomic clock schemes, atom interferometers, and other experiments using dressed atoms.

  15. Signal Processing in Cold Atom Interferometry-Based INS

    2014-03-27

    angular rotation. Additionally, because of their particle nature, the atoms may be treated as inertial masses and their movement is used to determine the...G(τ)δβ(τ) = Φ(∆t)xi + wdi where β(t) is a Brownian motion process with dispersion Q, andΦ is the discrete-time state transition matrix [14]. That is...identity matrix, I. βA and βG are 3 × 1 vectors of independent, unity Brownian motions, that is, βA(t) ∼ N (0, t · I) and βG(t) ∼ N (0, t · I). The rate

  16. Wave-equation dispersion inversion

    Li, Jing

    2016-12-08

    We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained from Rayleigh waves recorded by vertical-component geophones. Similar to wave-equation traveltime tomography, the complicated surface wave arrivals in traces are skeletonized as simpler data, namely the picked dispersion curves in the phase-velocity and frequency domains. Solutions to the elastic wave equation and an iterative optimization method are then used to invert these curves for 2-D or 3-D S-wave velocity models. This procedure, denoted as wave-equation dispersion inversion (WD), does not require the assumption of a layered model and is significantly less prone to the cycle-skipping problems of full waveform inversion. The synthetic and field data examples demonstrate that WD can approximately reconstruct the S-wave velocity distributions in laterally heterogeneous media if the dispersion curves can be identified and picked. The WD method is easily extended to anisotropic data and the inversion of dispersion curves associated with Love waves.

  17. Dispersion Decay and Scattering Theory

    Komech, Alexander

    2012-01-01

    A simplified, yet rigorous treatment of scattering theory methods and their applications Dispersion Decay and Scattering Theory provides thorough, easy-to-understand guidance on the application of scattering theory methods to modern problems in mathematics, quantum physics, and mathematical physics. Introducing spectral methods with applications to dispersion time-decay and scattering theory, this book presents, for the first time, the Agmon-Jensen-Kato spectral theory for the Schr?dinger equation, extending the theory to the Klein-Gordon equation. The dispersion decay plays a crucial role i

  18. Velocity Dispersions Across Bulge Types

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David

    2010-01-01

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (σ*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  19. Practical implementation of spectral-intensity dispersion-canceled optical coherence tomography with artifact suppression

    Shirai, Tomohiro; Friberg, Ari T.

    2018-04-01

    Dispersion-canceled optical coherence tomography (OCT) based on spectral intensity interferometry was devised as a classical counterpart of quantum OCT to enhance the basic performance of conventional OCT. In this paper, we demonstrate experimentally that an alternative method of realizing this kind of OCT by means of two optical fiber couplers and a single spectrometer is a more practical and reliable option than the existing methods proposed previously. Furthermore, we develop a recipe for reducing multiple artifacts simultaneously on the basis of simple averaging and verify experimentally that it works successfully in the sense that all the artifacts are mitigated effectively and only the true signals carrying structural information about the sample survive.

  20. Application of virtual phase-shifting speckle-interferometry for detection of polymorphism in the Chlamydia trachomatis omp1 gene

    Feodorova, Valentina A.; Saltykov, Yury V.; Zaytsev, Sergey S.; Ulyanov, Sergey S.; Ulianova, Onega V.

    2018-04-01

    Method of phase-shifting speckle-interferometry has been used as a new tool with high potency for modern bioinformatics. Virtual phase-shifting speckle-interferometry has been applied for detection of polymorphism in the of Chlamydia trachomatis omp1 gene. It has been shown, that suggested method is very sensitive to natural genetic mutations as single nucleotide polymorphism (SNP). Effectiveness of proposed method has been compared with effectiveness of the newest bioinformatic tools, based on nucleotide sequence alignment.